Prolonged dry spells in recent decades over north-central China
INTERNATIONAL JOURNAL OF CLIMATOLOGY Int.J.Climatol.35:4829–4842(2015)
Published online21April2015in Wiley Online Library (https://www.wendangku.net/doc/3013245701.html,)DOI:
10.1002/joc.4337
Prolonged dry spells in recent decades over north-central China and their association with a northward shift
in planetary waves
Jie Zhang,a,b*Laurent Li,a,c Zhiwei Wu a and Xingmin Li d
a Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster of Ministry
of Education,Nanjing University of Information Science&Technology,Nanjing,China
b Key Laboratory of Arid Climati
c Changing an
d Reducing Disaster of Gansu Provinc
e and CMA,Lanzhou,China
c Laboratoire de Météorologie Dynamique,IPSL/CNRS,UniversitéPierre et Marie Curie,Paris,France
d Institut
e o
f ShanXi Meteorology,Xi’an,China
ABSTRACT:Summer rainfall in north-central China,accounted for70%of the annual rainfall,is sensitive to anomalies in the East Asian summer monsoon(EASM)and westerlies due to lying in the EASM marginal belt.Summer rainfall and the durations and frequency of dry spells were investigated using daily rainfall data from332weather stations,the European Centre for Medium-range Weather Forecasting(ECMWF)re-analysis data and Climate Research Unit(CRU)surface temperature data.The results demonstrate that summer rainfall exhibits an‘early wetting later drying’pattern with a weak increasing in June and a dramatic decreasing trend in July and August(JA).Decreased rainfall in JA is associated with prolonged dry spells;
the frequency and durations of dry spells exceeding7days increase,especially for dry spells exceeding15days.This increase in dry spell duration is positively correlated with a northward shift in planetary waves expressed by the5700-gpm isoline at500hPa and the westerly jet at200hPa,which lead north-central China to close to the left of jet entrance and a positive vorticity convergence region on the high level,it is helpful to downward movements and less rainfall.The northward shift in planetary waves is affected by boundary forcing.Dramatic increases in temperature over the Tibetan Plateau(TP)result in a large temperature gradient and thermal contrast between the TP and mid-high latitude,and likely strengthening and widening the South Asian High(SAH)pattern and pressure gradient.These conditions contribute to the northward shift in planetary waves and prolonging dry spells.
KEY WORDS prolonged dry spells;planetary wave;temperature gradient;northward shift
Received7December2014;Revised12March2015;Accepted13March2015
1.Introduction
Northern China is the main agricultural,industrial and cultural centre in China.The region is situated within the marginal belt of the East Asian summer monsoon(EASM) or to the north of the EASM;therefore,the climate in this region is sensitive to anomalies in the EASM and to westerly.In the past30years,northern China has under-gone severe dry spells during the rainy season(Cheng and Zhou,2013).Dry spells are characterized by continuous days without substantial rainfall(>1mm day?1)(Zolina et al.,2013).Long-duration or persistent dry spells lead to droughts,and several droughts have occurred in northern China over the past30years.Moreover,it is well know that eastern China exhibits a‘southern flooding and north-ern drought’pattern,which refers to the increased rainfall over the middle to lower reaches of the Yangtze River basin and the decreased rainfall over Northern China *Correspondence to:J.Zhang,College of Atmospheric Science, Key Laboratory of Meteorological Disaster,Ministry of Education (KLME),Nanjing University of Information Science&Technol-ogy(NUIST),Ningliu Road219,Nanjing210044,China.E-mail: gs-zhangjie@https://www.wendangku.net/doc/3013245701.html, (Zhao et al.,2010).Especially during the recent period of substantial global warming,droughts have become more intense and more frequent,such as the droughts in2005 and2010in northern Shanxi province and Henan province (https://www.wendangku.net/doc/3013245701.html,/wiki/2010–11_China_drought). Droughts have major effects on agriculture,the ecologi-cal environment and the social economy.Therefore,the effective prediction of extreme droughts can minimize losses of goods and lives.Dry spells can be used as a reference index for potential droughts(Groisman and Knight,2008).Moreover,it is important to understand the physical mechanisms involved in dry spell dynamics. However,less attention has been given to the long-term variability in the duration of dry spells.
Dry spells are natural events that are associated with the duration of wet periods,which are the results of rain-fall.That is first decided by moisture transports mainly transported by EASM,therefore,many previous studies addressed the rainfall change in northern China and its relations with EASM.For example,the‘southern flooding and northern drought’pattern is associated with the weak-ening of the EASM circulation(Hu et al.,2003),which is forced by either a phase transition of the Pacific Decadal
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Oscillation(PDO)or recent warming of the tropical Pacific and Indian Oceans(Li et al.,2010a,2010b),furthermore, approximately70%of the drying trend with multi-decadal variability is related to the PDO-negative phase(Cheng and Zhou,2013).EASM circulation is affected by the land–ocean temperature gradients and thermal contrast(Li et al.,2010a,2010b),anomaly land thermal also leads to EASM circulation change,especially thermal anomalies in spring and summer over the Tibetan Plateau(TP),reduc-tions in the sensible heat flux over the TP have weak-ened the EASM circulation and postponed its seasonal changes(Duan et al.,2012).As a factor affecting the TP temperatures,TP snow cover(TPSC)exerts an effect on El Ni?o-Southern Oscillation(ENSO)tele-connections with East Asia,whereas the ENSO only exhibits a signif-icant positive correlation with the EASM during reduced TPSC summers(Wu et al.,2012a).In addition,Yu et al. (2004)attributed the decreased rainfall pattern over north-ern China to the summertime cooling in the upper tropo-sphere over extra tropical East Asia,which was assumed to be associated with stratosphere–troposphere interactions. Decreased rainfall and frequent droughts in northern China are associated not only with the EASM circulation but also with wave activities associated with wester-lies because northern China just located in the northern marginal belt of the EASM.Moreover,frontal precipita-tion primarily contributes to wet conditions in summer due to the convergence of cold masses by westerlies and warm moist masses by EASM.The effects of the EASM and the westerlies exhibit non-uniform in northern China, north-east China is largely influenced by the EASM, whereas north-west China is primarily influenced by the westerlies.In recent decades,rainfall over north-west China has exhibited an increasing trend(Chen and Huang, 2012),which contradicts the rainfall trend over north-east China.Decreased rainfall and droughts over north-central China are commonly influenced by Rossby waves gen-erated by the westerlies and EASM moisture transport. Through westerly circulation,the North Atlantic Oscil-lation(NAO)related to the North Atlantic sea surface temperature(SST)distribution modifies the effects of the ENSO on the EASM,by enhancing a distinct Rossby wave train within the prevailing westerlies over northern Eurasia(Wu et al.,2012b).The positive anomalies in the northwestern North Atlantic SST pattern also excites a distinct Rossby wave train,which leads to an anticyclonic anomaly near Lake Baikal;this phenomenon is related to drought/flood over north-central China(Hu and Feng, 2008;Zhang et al.,2013).With respect to high-latitude forcing,Arctic ice loss is favourable for cyclonic anoma-lies in the lower troposphere over the Arctic,which results in a weaker polar cell and a stronger Ferrel cell.The final result is a strengthening of the anticyclonic anomaly near Lake Baikal,which is related to meridional shifts or a northward elongation and anomaly in planetary wave ridges near Lake Baikal(Zhang et al.,2014).All the previous findings suggest that anomalous Rossby waves in the mid-latitude are related to rainfall and drought in north-central China.
Reduced rainfall and drought in north-central China is primarily associated with the decreased frequency of precipitation events(Zhai et al.,2005),which corresponds to an increase in dry spells.In the present work,we investigate the possible mechanisms underlying drought and decreased rainfall based on the characteristics of dry spells,including the duration and frequency of dry spells during the rainy season in north-central China,because prolonged dry spells increase the frequency of droughts. Furthermore,the potential relationship between dry spells and atmospheric circulation anomalies is investigated to explore relevant mechanisms of drought events on decadal scales.In this study,the data and methods are described in Section2.The temporal and spatial variability of dry spells and their relationships with planetary waves are discussed in Section3.The possible mechanisms of planetary waves and prolonged dry spells are explored,and the surface temperature differences between the most recent three decades and the preceding three decades are analysed in Section3.The model sensitivity simulations are also discussed in Section3.Finally,conclusions are presented in Section4.
2.Data and methods
2.1.Study area
Northern China corresponds to the northern extent of China,encompassing the eastern,central and western por-tions of the country.Summer precipitation over northern China accounts for more than70%of the annual precipita-tion.Summer rainfall over north-east China is primarily affected by the EASM.Moreover,summer rainfall over north-central China is affected by both the EASM and the westerlies.Western China is generally regarded as north-western China,which corresponds to the plateau climate and arid climate.Summer rainfall in this region is mainly influenced by the westerlies.In this study,we focus on the region east of100°E,the332weather stations are pre-sented in Figure1and the study region is also showed in the Figure1(rectangular region,north-central China is defined by37°–45°N and104°–114°E).North-central China encompasses the middle reaches of the Yellow River,the second largest river,and the climatic variabil-ity in this region is large.We selectively analyse rainfall events and dry spells over north-central China.
2.2.Datasets and methods
Three datasets are used in this study.Daily precipitation data in summer(JJA)from356weather stations in northern China are used,which correspond to53a of data from1961 to2013,24stations from356stations are rejected due to discontinuous or moving stations,and finally332stations are selected.The discontinuous data include the rainfall gaps in the data records during JJA due to uncertainty rea-sons,and such gaps cannot be ensured whether it is rainy day or not,and there are more than two continuous days with gap in the data records,or total days exceed5days in JJA.Other gaps in the data records are revised according to
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Figure 1.Location of north-central China (rectangle;37°–45°N,
104°–114°E)and 332stations distribution in Northern China.
daily temperature and relative humidity within continuous lead-lag 2dry days,because temperature and humidity are recorded at that very day.If temperature difference at that very day with gap rainfall record with averaged temperature in continuous 5days is less than 1°and rel-ative humidity difference is less than 5%,the gap record day must be dry day,otherwise it is uncertainty day.The data are used for calculating summer rainfall events and dry spells,which are two parameters that reflect dry/wet conditions.Dry spell is characterized by continuous days without substantial rainfall (>1mm day ?1)in JJA,this threshold excludes very light precipitation and partially accounts for the limited accuracy of rain gauges (Klein and Konnen,2003;Zolina et al.,2013),and it is calculated for all stations.The study mainly aimed at the duration of dry spells longer than 7days,so as to investigate its relations with planetary wave movements,because long-time dry spells correspond to stable and large-scale circulation of planetary wave.The European Centre for Medium-range Weather Forecasting (ECMWF)re-analysis Interim (ERA-Interim)data are used to analyse atmospheric cir-culation anomalies,such as potential heights and Rossby waves at 500hPa,the westerly jet at 200hPa (Bromwich et al.,2007).For comparison with the atmospheric circu-lation before 1980,ERA40data are used to represent the mean Rossby wave position before 1980(i.e.1958–1980).Although the ERA40resolution is lower than that of the ERA-Interim dataset,the ERA40dataset can be regarded as a reference state,by comparing the 5700-gpm latitude positions of ERA40with ERA-Interim in JJA during the overlapping periods (from 1979to 2002)around our study region (70°–150°E,30°–50°N),the systematic bias of latitude positions is 0.38°,?0.17°and 0.31°N corresponding to June,July and August,respectively,it is regarded as reference for the difference of 5700-gpm
isoline between ERA40and ERA-Interim.The surface air temperature data are from the Climate Research Unit (CRU)Ts 3.10.01dataset,which encompasses the period from 1901to 2011(Harris et al.,2014).The data error is calculated based on the CRU 3.10dataset at a reso-lution of 0.5°×0.5°(https://www.wendangku.net/doc/3013245701.html,/view/https://www.wendangku.net/doc/3013245701.html,_ATOM_dataent).Surface air temperatures are used to analyse the temperature gradient over northern China and the adjacent regions.
The following statistical metrics and methods are applied in this study:correlation coefficients,trend anal-ysis and diagnostic analysis.Reliability tests are also performed by using Mente Carlo test,and it is proved that Mente Carlo method is better than Pearson’s correlation (Stephen,1998).The article also shows correlation coeffi-cient between trend line (linear and nonlinear)and original data distribution,and some correlation coefficients are showed in the Figures 3,4,and 7,and 90%confidence level is 0.28,95%confidence level is 0.32.2.3.
CAM5model and experiments
The atmospheric module of the community earth system model,i.e.the Community Atmospheric Model version 5.1(CAM 5.1)(Neale et al.,2011),was developed at the National Center for Atmospheric Research.The dynam-ical scheme includes four frameworks,including a finite volume method,a spectral element method,an Euler method and a half-Lagrange method.This study applies the finite volume dynamic framework with a horizontal resolution of 1.9°×2.5°with 30vertical layers in the σ-p vertical coordinate.CAM 5.1is coupled to the CLM4land process model.In this study,several physical processes,including radiation processes,cloud effects,convection,boundary layer effects and other physical processes,are represented in the model according to the default options.Only the land surface data are changed in the sensitivity experiments.A detailed description of the model is avail-able at https://www.wendangku.net/doc/3013245701.html,/models/atm-cam/.This study attempts to change the surface characteristics over the TP to simulate increases in air temperature over the TP.The surface character changes include receding glaciers,permafrost degradation,desertification,decreased soil moisture and vegetation degradation.One of the sensitiv-ity experiments includes a decrease in vegetation cover by 30%(25°–40°N,70°–100°E);the decrease corresponds to a fit for the vegetation trend throughout the first of 21st century (Zhang et al.,2014).The initial background data are the mean values from the recent three decades (i.e.1980–2010),including atmospheric data and surface data.The control simulation and sensitivity simulation are performed for 15a;the results in JA for the last 10a are analysed in this study.2.4.
CMIP5historical simulation
In order to further test statistical results and CAM5results,we analyse the historical simulations (1950–2005)from global warming A1B stabilization experiments (with an atmospheric CO 2concentration of history ppm)conducted
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?0.0100.010.020.03Figure 2.Spatial distributions of the mean duration of dry spells exceeding 7days (a,unit:days),the number of dry spells exceeding 7days (b),and the trend in the duration (c)and number (d)of dry spells exceeding 7days.The black dashed lines in (c)and (d)represent the 95%confidence level
by Mente Carlo test.The blue rectangle represents north-central China,and the thin pink lines represent provincial boundaries.
by 2state-of-the-art ocean–atmosphere general circula-tion models that participated in the Fifth Assessment Report (AR5)coordinated by the Intergovernmental Panel on Climate Change (IPCC).The models include the God-dard Institute for Space Studies Model E2-H (GISS-E2H)and L’Institut Pierre-Simon Laplace Coupled Model,ver-sion 5(IPSL CM5A).The reasons to select CMIP5models are that increasing temperature over TP is the result from nature variability and greenhouse gasses and its decadal variable is synchronous with anomaly SST and global warming (Klein et al.,2004).AR5historical simulation can realize their synchronous change due to considering SST and greenhouse gasses contents.3.Results and discussion
3.1.
Dry spell distribution over northern China
The duration of dry spells is opposite to the trend for rain-fall variability,therefore,the duration of dry spells could reflect dry/wet condition and drought/flood.Figure 2(a)shows the spatial distribution in the mean duration of dry spells exceeding 7days;the maximum of the mean dura-tion is longer than 16days,occurring over the northern portion of northwestern China.Moreover,the minimum of the mean duration is 9.3days,occurring over the southern portion of northwestern China.Duration in north-central China is 12.1days.There are three peak centres in the mean duration of dry spells,in northwestern (39°–42°N,
100°–105°E),northeastern (40°–45°N,120°–125°E)and eastern (34°–38°N,114°–120°E)China,those durations are 18.1,13.5and 14.1days,respectively.Moreover,two minima centres occur in the east of the TP and North China,i.e.near Beijing (37°–42°N,112°–118°E).These minima centres occur near mountains;therefore,the rel-atively low duration of dry spells is related to orographic precipitation.Figure 2(b)shows the number of dry spells with the duration exceeding 7days in summer.Most regions in northern China have exceeding three times dry spells;one maximum centred in the north-central China,it is 5.6times;the other maximum and minimum val-ues agree with the duration of dry spells presented in Figure 2(a).The maximum values are 4.2,3.3and 3.9times,respectively.By multiplying by the duration of the dry spells,we find that the dry spells exceeding 7days lasted for 76,45and 58days for three maximum centres,respectively,and 68days in north-central China,encom-passing 83,48,63and 74%of the summertime (JJA).These long durations could lead to summer droughts.Figures 2(c)shows the duration trend rate of dry spells.The duration trend rate of dry spells exhibits pronounced zonal variability.For example,dry spells occur more fre-quently in north of 37°N and east of 108°E;however,these events occur less often south of 37°N.The trend rate is 0.025days per event per year;however,except for the east portion,increasing trend rate is not significant at the 95%confidence level.In Figure 2(d),the trend in the number of dry spells increases in most regions of northern
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Figure 3.Temporal trend in summer (JJA)rainfall (a)and the mean number of rainfall events in north-central China (b),dotted line is mean value and thick line is three order trend line,r is correlation coefficient of rainfall and the numbers of rainfall events with its three order trend,respectively,
90%confidence is 0.28and 95%confidence is 0.32for one-sided regression (it is similar hereinafter).
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Figure 4.Temporal trends in June and JA rainfall (a)and the mean number of rainfall events in June and JA in north-central China (b).The top lines are for JA;the bottom lines are for June,dotted line is mean value and thick line is trend line.r is correlation coefficient of rainfall and the numbers
of rainfall events with its three order trend,respectively.
China;there are a few small regions in which the increase rate is not observed.The pronounced increasing trend is significant at the 95%confidence level,in the region with an increasing occurrence of dry spells (35°–45°N,104°–123°E).The increasing dry spells events and weak increasing duration of dry spells suggest that drought events are becoming more likely in northern China.
The study region [blue rectangle,north-central China (37°–45°N,104°–114°E)]is one of the regions exhibit-ing an obvious increase in the number of dry spells and partly weak increase in duration.Similarly,another region exhibiting an increase in both the duration and number of dry spells is defined by the boundaries of north-east China (38°–42°N,115°–123°E).Rainfall and dry spells in the
north-east China are primarily affected by the EASM (Li et al.,2010a,2010b);however,rainfall and dry spells in the north-central China need further exploration.3.2.Temporal change in summer rainfall over north-central China
Figure 2shows a pronounced increasing trend in both the duration and number of dry spells over north-central China;these trends are associated with rainfall.Figure 3shows the time series of total JJA rainfall (Figure 3(a))and the number of JJA rainfall events (Figure 3(b))over north-central China.The total JJA rainfall and the num-ber of rainfall events exhibit the following variability:a decrease trend after 1990,which precedes a mean value
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S t a r t d a t e o f d r y 15+ e p i s o d e Figure 5.Dry spells histogram (a,unit:%)and duration of dry spells exceeding 7days for all stations in north-central China in JJA (b,unit:days).The duration of dry spells exceeding 15days for all stations in north-central China in JJA (c,unit:days)and the corresponding start date (d,date)
are also depicted.
of rainfall,and infrequent rainfall events occurred after 1990.The decrease rainfall and rainfall events contrast the increase trend in the duration and number of dry spells events.The time series of rainfall for each month,i.e.June,July and August,is also analysed (Figure 4).The trend for each month differs,especially in June,it exhibits a dif-ferent rainfall trend compared with which in the other 2months.Rainfall and rainfall events in June exhibit a weak increasing trend,whereas rainfall and rainfall events in JA (July and August)have the same trend as the JJA rainfall trend.This pattern about summer rainfall exhibits an ‘early wetting later drying’pattern,which suggests that rainfall in JJA is affected by different mechanisms.A decrease in the number of rainfall events corresponds to prolonged dry spells,which possibly explains the ‘early wetting later dry-ing’pattern.Therefore,we can explore decrease rainfall through prolonging dry spells and its mechanism.3.3.Temporal change in dry spells over north-central China
To explore the change regulation of dry spells,the duration of every dry spell from all stations over north-central China (i.e.the study region)is plotted.Figure 5(a)shows a histogram of dry spell events from 1day to 49days in length;the occurrence frequency decreases as the duration increases.There are four peak frequency showing four time periods,those are 3–6days,8days,12–15days and 19–20days.Moreover,51%of the events are longer than 7days,36%of the events are longer than 12days and events exceeding 15days account for 18%of the events.These longer dry spell events should be given more attentions because they can more easily lead to droughts.
Figure 5shows the duration of dry spells exceeding 7days (Figure 5(b)),indicating that these longer duration events ranged from 8to more than 50days.From the scatter diagram,we can conclude that the durations of dry spell is highly asymmetrical as a function of time,i.e.most stations have recently reported longer dry spells than those during the early period;the average duration in the region is approximately 12days.Moreover,the annual average duration of dry spell exhibits a pronounced increasing trend.Furthermore,events exceeding the mean value increase with time.
Figure 5(c)shows a scatter diagram of events with a duration exceeding 15days.This figure demonstrates that fewer dry spells exceeding 25days are found before 1977.However,after 1977,an increasing frequency of longer dry spell events occurs.This trend suggests that increasing stations experience prolonged dry spells or dry spells are more frequent at individual stations.Specifically,events exceeding 20days account for 42%of all those events with longer than 15days durations (figure omitted);these events are primarily found after 1977.Does prolonged dry spell related to global warming?It is worthy of paying attentions,because global warming signal was just clear during the period.Figure 5(d)shows the start dates of long dry spells (exceeding 15days);the start dates are primar-ily distributed in June (150–180)before 1977,however,most cases occurred in JA (181–240)after 1977.This shift shows that prolonged dry spells in JA is an impor-tant factor that contributes to decrease rainfall in JA,and it is favourable for an ‘early wetting later drying’pattern.This pattern is associated with an anomalous circulation of the EASM and Rossby waves caused by the prevailing
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Figure 6.The 5700-gpm isoline at 500hPa from June to August for the recent three decades,mean from 1958to 1980,and anomaly years of dry spells (a–c).The westerly jet position obtained from the U component of the wind at 200hPa from June to August for the recent three decades and
anomaly years of dry spells (d–f).
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Figure 7.Correlation coefficients between dry spells exceeding 7days in length and the position of the mean 5700-gpm isoline (100°–114°E)at 500hPa (left panel),and mean westerly jet at 200hPa (middle panel),and the EASM index from Shi in JA (right panel).Blue rectangle is the study
region in north-central China.
westerlies because long dry spells are also related to plan-etary wave anomalies.
3.4.Decadal change of planetary waves
Fields of 500hPa are selected for analysing anomaly circulation because numerous radiosondes and satellite retrievals information are constrained in the fields,the atmosphere is free from surface effects and upper-level wave patterns appear in the fields,all these ensure the high precision information about planetary wave movement.The 5700-gpm isoline at 500hPa passes through north-central China in July and August,therefore,5700-gpm
isoline is selected for reflecting planetary wave anomality that directly related to dry spells in JA over north-central China.
Figure 6(a)–(c)shows the 5700-gpm isolines in summer over the recent three decades from ERA-Interim and the mean isoline before 1980from ERA40dataset.The figure also presents isolines from six anomalous years (i.e.1991,1999,2001,2002,2005,2010);the anomalous years with longer dry spells in JA are selected according to the duration of the dry spells longer than mean duration from those more than 15days duration in JA.The isolines in the three decades are similar,exhibiting a slight northward
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Figure 8.JA U velocity distributions (unit:m s ?1)from ERA-Interim,JA Westerly jet position with larger than 30m s ?1from mean U velocity (thin black line,unit:m s ?1),the JA jet centre in 1980s (blue thick line)and after 2000s (red thick line),Yellow rectangle is the study region in north-central
China.
shift in June to the east of 100°E (Figure 6(a)).However,this pattern is different from the isolines in https://www.wendangku.net/doc/3013245701.html,pared with the 1980s and the mean isoline before 1980,the 5700-gpm isolines in JA (Figure 6(b)and (c))in the 1990s and the 2000s exhibit northward shifts between 80°and 120°E.Moreover,at approximately 120°E or to the east of this location,the 5700-gpm isolines are either similar or are shifted southward over the recent two decades.This result is in accordance with the findings presented in Figure 5and decrease rainfall in JA in Figure 4,i.e.the northward shift in the 5700-gpm isoline is possibly associated with prolonged dry spells.
The westerly jet is a component of the planetary system.To reveal further the northward shift in the atmospheric circulation,the westerly jet position is also analysed over the recent three decades (Figure 6(d)–(f)).Compared with the 1980s,the westerly jet during the recent two decades exhibits a northward shift to the west of 95°E;however,a southward shift is found between 95°and 130°E in June (Figure 6(d)).Moreover,the westerly jet exhibits a northward shift during the recent two decades between 80°and 140°E (except at approximately 120°E)in July (Figure 6(e)).Furthermore,the westerly jet exhibits a northward shift between 90°and 110°E and to the east of 130°E during the recent two decades;however,a south-ward shift is observed between 110°and 130°E in August (Figure 6(f)).These changes indicate that the westerly jet movement on the synoptic to planetary scale is within approximately 20–50longitudes;the westerly jet nearing the north-central China exhibits a northward shift in JA and a southward shift in June.
3.5.Correlation of dry spells with planetary waves We first explore the ‘early wetting later drying’pattern by exploring direct circulations using the 5700-gpm iso-line position (latitude).Figure 7(a)shows the correlation coefficients of the regional average location (latitude)of 5700-gpm isoline (100°–114°E)over north-central China with the duration of dry spells in JA,and the reason to select the regional average location of 5700-gpm isoline is that the isoline location just located between the ridge and rough of one planetary wave under 30years on aver-age condition,and the meridional changes of the position is almost synchronous,so,regional average positions are used to reflect wave movements and its relations with dry spells.A majority of northern China exhibits positive cor-relations,specifically,both the north-central and western regions exhibit high correlations that surpass the 95%sig-nificance level of Mente Carlo test.This finding suggests that prolonged dry spells correspond to a northward shifts in the 5700-gpm isoline.
The regional average of westerly jet in the range (100°–110°E)is also performed,and the location of west-erly jet is smaller than the location of 5700-gpm isoline,because westerly jet from 110°to 114°E in August has different decadal change with the location from 100°to 110°E,the reason to select the regional average of westerly jet location is the same as selection of 5700-gpm isoline location.Figure 7(b)shows the correlation coefficients of the averaged jet location with the duration of dry spells in JA.A majority of northern China exhibits positive correlation distributions,and both the north-central and
NORTHW ARD PLANETARY W A VES CONTRIBUTE TO PROLONGED DRY SPELLS OVER NORTH-CENTRAL CHINA
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Figure 9.Temporal trend in the location of the 5700-gpm isoline at 500hPa and the westerly jet in JA (a)and a scatter plot of their relationship and one-sided regression line (b).The temporal trend in the geopotential height at 500hPa in JA (c)and a scatter diagram between the 5700-gpm isoline
and the geopotential height are also depicted.r in (b)and (d)is the correlation coefficient of one-sided regression,respectively.
western regions exhibit high correlations that surpass the 95%significance level of Mente Carlo test.This finding suggests that prolonged dry spells also correspond to a northward anomaly of westerly jet position,and this relation is the same as dry spells with 5700-gpm isoline shift.Both the analysis announces that dry spells are associated with north shift in planetary wave.
Dry spells are also associated with moisture transport from Pacific and Indian ocean,which decided by EASM intensity and the position of the western Pacific subtropical high (WPSH),the study analyses correlation coefficients between the EASM index and the duration of dry spells in JA,so as to explore the effect of EASM intensity on dry spells in northern China.The EASM index from Shi and Zhu (1996)as summarized and assessed by Wang et al.(2008)is used in this study.A strong positive index reflects strong EASM and heavy rainfall.In a comparison of the recent 60a of the EASM,the EASM index shows that the EASM has been undergoing a weak period over the recent three decades.Furthermore,the correlation between the duration of dry spells and the EASM exhibits an east–west
distribution (Figure 7(c)),which is similar to that of the Mei Yu frontal pattern,i.e.a negative correlation belt is at 33°–38°N;however,the correlation is positive in the north of this belt,which shows that a strong EASM corresponds to increased rainfall and decreased dry spells in the south of 38°N;this pattern is not favourable for rainfall in the north of 38°N and over north-central China,and a weakened EASM is not a unique contributor to prolonged dry spells,because the correlation coefficient between the EASM and dry spells does not pass the 95%significance level of Mente Carlo test in large range,except for some regional locations.A possible reason for reversed correlation between north-central China and south 38°N is that the EASM could not extend to north-central China.The Figure 7also indicates that planetary waves from the prevailing westerlies are the primary contributors to prolonged dry spells over north-central China.
EASM contributes main moisture transport for rainfall in northern China,however,planetary waves contribute circulation background and vertical upward movement for rainfall,and good relationship between dry spells
4838J.ZHANG et al.
and planetary waves position shows that vertical upward movements change with northward shift in planetary waves.Westerly jet positions can reflect vertical move-ment and rainfall positions,the U vector larger than30 m s?1shows westerly jet range and the largest U vector position shows jet core position.Figure8shows U vector distribution at200hPa,and jet centre position from mean U in1980s and after2000s.It is found that jet in the west of120°E is northward shift after2000s by comparing with jet in1980s;jet(covers the range within30m s?1) is wide,it is from71°E to the east boundary and from 29°to43°N,the jet core with U larger than37m s?1is in the east of110°E.North-central China just lies on the left of jet entrance,north shift of westerly jet results in north-central China closed to jet entrance,where there are cyclonic shear,positive vorticity and negative relative vorticity advection,which are favourable for convergence at high levels and divergence at low levels,and all which are further for downward movement and decreasing rain-fall.Therefore,northward shift in westerly jet is one of important reasons leading to prolonged dry spells.
The planetary system is the background of synoptic-scale systems,and a northward shift in the planetary wave necessarily leads to a northward shift in synoptic-scale systems in mid-latitude,such as shortwave troughs,which are directly related to rainfall.Therefore,a northward shift in planetary system is inferred favourable for a northward shift in shortwave trough,which also contributes to dry spells.Without doubt this inference still needs to be testified hereafter.
3.6.A possible mechanism underlying the northward shift in planetary waves
The decadal change in westerly jet is related to decadal change in northward shift in the location of5700-gpm iso-line,and what the mechanism about the northward shift in planetary wave is worthy of discussion.Figure9shows that the JA westerly jet and5700-gpm isoline locations (Figure9(a))exhibit a positive correlation(Figure9(b)). The westerly jet and the5700-gpm isoline locations in JA exhibit the same variations,which means that the westerly jet possibly follows the northward shift in the planetary wave.As noted above,global warming possibly leads to a lifting of the entire atmosphere,which assists in increas-ing the potential height(Hu,1997).Figure9(c)shows the potential height at500hPa in JA,which is indica-tive of an approximate location for the5700-gpm isoline over north-central China.The potential height exhibits an increasing trend,i.e.it is low in the1980s and high in the1990s and the2000s.The correlation with the position of the5700-gpm isoline(Figure9(d))is weak;however, this relationship is not significant at the95%significance level.Which indicates increasing height in low-middle tro-posphere is not the primary factor resulting in north shift in planetary wave,but other https://www.wendangku.net/doc/3013245701.html,ing orthogonal regres-sion analysis,the total relation between the wave position and jet position and potential height is expressed(Equation (1)).The equation shows that the potential height item is ignored by orthogonal regression analysis,due to no significant level,which further shows good correlations between the jet positions and wave positions,in addition, increasing in the potential height was not the main contrib-utor to wave position.
L w=0.578L j
(
R2=0.21,F=7.577,P=0.0095
)
(1) Where,L w is wave latitude position,L j is jet latitude position,R2is multiple correlation coefficient,F and P are F statistic and its probability(P)value,respectively.
As one of planetary systems,the westerly jet exhibits regional changes in the location throughout the mid-latitudes(figure omitted)in a global warming scenario.In some regions,the westerly jet shifts northward,whereas in other regions,the jet steam shifts southward.Such a position change may lead to the spatial coexistence of floods and droughts through the mid-latitudes,which may be associated with the Indus River flood in Pakistan in 2010and other extreme events,such as the European heat wave in2003and the heat wave in the United States in 2011(Petoukhov et al.,2013).Li et al.(2010a,2010b) found that the EASM rainfall responses to global warm-ing are not related to changes in rainfall intensity but, rather,to changes in the rainfall location.EASM rainfall is also associated with a southward shift in the westerly jet over East Asia(considering only regions between120°and 130°E).A meridional asymmetric warming with the sur-face warming over the mid-to high-latitude regions could explain southward shift in the westerly jet over East Asia. Moreover,Woollings et al.(2010)found a northward shift in the North Atlantic eddy-driven pole-ward westerly jet over the North Atlantic.These findings not only describe regional characteristics of westerly jet shifts but also reveal the different mechanisms related to location and time-scale changes of the westerly jet.
Considering that circulation changes are typically inti-mately coupled with low boundary forcing anomalies,it is possible that inter-decadal changes in low boundary forc-ing lead to inter-decadal northward shifts.To explore the possible mechanisms underlying the northward shift in the westerly jet over north-central China,we first analyse the boundary forcing using the surface temperature differ-ence between the most recent three decades(1981–2011) and the preceding three decades(1951–1980).The sur-face temperature data used in this study are from the CRU Ts3.10.01dataset(Figure10).The temperature in recent three decades indicates the effects of global warm-ing,and it indicates spatial coexistence in a global warm-ing scenario.West of105°E,there is a small increase or decrease in temperature in the mid-to high-latitudes (40°–60°N,80°–105°E).Moreover,there is a concor-dant increase in temperature over the TP(28°–40°N, 80°–100°E).These spatial differences in increase tem-peratures result in an anomaly in the increase temper-ature gradient between TP and the north of TP,which opposes the north–south temperature gradient anomaly to the east of105°E.The zonally averaged temperature dif-ferences between80°and105°E are plotted(Figure10(b)).
?1?0.500.51 temperature difference between the most recent three
(a)and the absolute temperature difference
shifts in inter-tropical convergence zone(ITCZ)with an anomalously strong north-minus-south SST gradient over the eastern equatorial Indian Ocean(90°–110°E)(Weller et al.,2014).Whether SST gradient in Indian ocean drives north shift ITCZ,and then it also contributes to north shift subtropical zone and north shift planetary waves in the mid-latitude,except for increasing TP temperature?Or, northward shift in westerly jets and SAH are the common results of ITCZ in Indian Ocean and increasing TP temper-ature?These questions also need further exploration.
3.7.Simulation of the northward shift and anomaly rainfall
To simulate the planetary wave shift caused by the pro-nounced increase in temperature over the TP that ulti-mately resulted in a larger temperature gradient,this study attempts to change the surface characteristics over the TP to simulate increases in air temperature over the TP.The surface character changes include receding glaciers,per-mafrost degradation,desertification,decreased soil mois-ture and vegetation degradation.One of the sensitiv-ity experiments includes a decrease in vegetation cover by30%(25°–40°N,70°–100°E)in the study area;the initial background data are the mean values from the most recent three decades(1980–2010),including rele-vant atmospheric data and surface data.The control sim-ulation and the sensitivity simulations are performed for rainfall.The same as data section definition of dry spell, rainfall in model data is characterized by>1mm day?1, Figure11(b)shows mean JA rainfall calculated from con-trol simulations(thin thick line),and anomaly JA rainfall (shadow),which is the difference between sensitivity and control simulations.It is found that north-central China exhibits negative anomaly rainfall,which is helpful for prolonging dry spells,and this result is agreed with our analysis as https://www.wendangku.net/doc/3013245701.html,paring anomaly rainfall centres with mean rainfall centres,the anomaly rainfall centre is northward shift in the west China but south shift in the east China,and positive anomaly rainfall over TP occurred in the north of the rainfall centre over TP,negative anomaly rainfall covered wide range in the Asian mid-latitude (35°–55°N,70°–115°E),showing obvious climate shift on the planetary scale;positive anomaly rainfall over east China(30°–40°N,east of110°E)occurred in the south of the rainfall centre(35°–45°N).Anomaly rainfall shifts show the same change with5700-gpm isoline and westerly jet(figure omitted).Increasing temperature around Lake Baikal is significantly related to decreased intensity of northern EASM(Zhu et al.,2012);however, the increasing temperature located in the east of Lake Baikal in CAM5,it would affect the precipitation.
In order to decrease uncertainty of CAM5simulation, the study also analysis ensemble mean of two histori-cal simulation results(1950–2005)from global warming A1B stabilization experiments conducted in the IPCC AR5
?2
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80°E 90°E
100°E 110°E 120°E 130°E
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6
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?3
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123Figure 11.The air temperature difference at 2m (unit:°C)and the 5700isoline of control (blue thick line)and sensitivity (pink thick line)simulation (a),mean precipitation (black line,unit:mm)and anomaly precipitation (shadow,unit:mm)between the sensitivity and control simulations from the CAM5model and 5700isoline (b).Red rectangle is the study region in north-central China.Blue thin line is lake-land boundary,pink dash line
is province boundary.
(see Figure 12).The difference between the most recent three decades (1981–2005)and the preceding three decades (1951–1980)is analysed.There are positive temperature centres over the TP,south of Lake Baikal,whereas negative temperatures are located in the mid-to high-latitudes (40°–60°N)and south of East Asia (south of 40°N and the east of 100°E).The 5700-gpm isoline exhibits a northward shift (from 70°to 110°E).North-central China exhibits negative anomaly rainfall,which is helpful for prolonging dry spells,this result is well agreed with our analysis and CAM5results as above,how-ever,no obvious shifts in the position of anomaly rainfall.In all,increasing temperature over TP and temperature gradient between TP and mid-high latitude are helpful for northward shift in planetary waves,which further leads to decreasing rainfall and prolonging dry spells over north-central China.According to the above analysis,an increased temperature gradient between the TP and the mid-to high-latitudes is favourable for an increase in the thermal contrast and pressure gradient,which likely strengthens and widens the SAH and is also favourable for a northward shift in the westerly jet,furthermore,north-central China is closed to the left of jet entrance,
negative relative vorticity advection leads convergence at the high level and downward movement,and finally prolonging dry spells.Therefore,increased temperature over the TP should exhibit nonlinear relationships with dry spells or rainfall events in the study region.However,the mechanism how increase temperature over the TP is related to a strengthened and widened SAH requires additional exploration.
4.Summary and conclusions
Summer rainfall in north-central China exhibits an ‘early wetting later drying’pattern,which is indicated by a slight increase in rainfall in June and a subsequent decrease in JA.The JA rainfall trend is the same as the JJA rainfall trend.The pattern shows that rainfall in JJA is affected by different mechanism.Rainfall in JA is associated with dry spells.Two large regions exhibit an increasing trend in both the duration and number of dry spells;these regions include north-central China and north-east China.In our study region,the durations and numbers of dry spells exceeding 7days exhibit a pronounced increase,especially
NORTHW ARD PLANETARY W A VES CONTRIBUTE TO PROLONGED DRY SPELLS OVER NORTH-CENTRAL CHINA
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Figure 12.The air temperature difference at 2m (unit:°C)and the 5700isoline of control (blue thick line)and sensitivity (pine thick line)simulation
(a),mean precipitation (black line,unit:mm)and anomaly precipitation (shadow,unit:mm)between the sensitivity and control simulations from two Cmip5models and 5700isoline (b).Red rectangle is the study region in north-central China.Blue thin line is lake-land boundary,pink dash line
is province boundary.
those dry spells exceeding 15days.Such prolonged dry spells and dry events are favourable for droughts and heat waves.
Prolonged dry spells in north-central China are directly associated with anomalous atmospheric circulation pat-terns and the location of the planetary waves,which can be directly reflected by the location of the 5700-gpm isoline at 500hPa over north-central China.A correla-tion analysis shows that there is a consistently positive correlation between the 5700-gpm isoline location over north-central China (90°–114°E)in JA and the duration of dry spells in JA.High correlation regions are found in north-central China and to the west of this region.More-over,the position of 5700-gpm isoline exhibits a north-ward shift during the recent two decades,which agrees well with prolonged dry spells in north-central China.This study also analyses the position of the westerly jet.The westerly jet over north-central China also exhibits a northward shift;therefore,the northward shift in the plan-etary waves near north-central China is a primary cause of the prolonged dry spells,and northward shift leads
north-central China just to close to the left of jet entrance,with the stronger positive vorticity,negative relative vortic-ity advection and convergence at high levels,and then the stronger downward movement at low levels,which is help-ful to decreasing rainfall and prolonging dry spells;in addi-tion,Asian mid-latitude just located downward movement climate and negative anomaly rainfall belt (35°–55°N,70°–115°E),which is also conductive dry spells.We also analyse the correlation between the duration of dry spells and the EASM index from Shi.A positive correlation is primarily found in north-central China;however,this cor-relation is not significant at the 95%confidence level,which shows that water vapour transport from a weakened EASM is not the main contributor to the prolonged dry spells.
Northward shift in the westerly jet is generally related to the temperature gradient.These anomalies are also associated with global warming (Li et al.,2010a,2010b).The mechanism explored by using a global atmospheric general circulation model shows that a pronounced increase in temperature over the TP,on the one hand,acts
4842J.ZHANG et al.
to increase the temperature gradient to the north,which is favourable for strengthening northward shift in the westerly jet;on the other hand,it is likely strengthening and widening SAH to northward,which leads to north-ward shift waves and westerly jet on the north of SAH. This indicates that the increasing temperature over the TP exhibits nonlinear relationships with dry spells and rainfall over the north-central China.However,the prolonged dry spells are weakly associated with water transport by the EASM in late July.Future work will perform quantitative evaluation for each function of the EASM and the north-ward shift in the planetary waves.On inter-annual scale, ENSO,PDO and WPSH would lead to anomaly circula-tion and anomaly dry/wet(Cheng and Zhou,2013).We also hope to explore other forcing sources or wave trains that may affect the northward shift in the planetary waves, because planetary wave shifts show disaccord change over the mid-latitude regions in Northern Hemisphere. Planetary waves are the background of the synoptic system.A northward shift in planetary waves may lead to a northward shift in shortwave troughs,which are directly related to rainfall.Does a northward shift in these troughs reduce rainfall in north-central China?In addition,how does increase temperature over TP strengthen the SAH? Does north shift in westerly jet and SAH associate with ITCZ north shift in Indian Ocean?These questions should be explored thereafter.
Acknowledgements
Data to support this article are from the China Meteo-rological Administration website(https://www.wendangku.net/doc/3013245701.html,/ home.do).The data can be downloaded as the sec-ondary usage.This research was jointly supported by the National Natural Science Foundation of China under Grant No.91437107and No.41375155,by Arid Project (IAM201403),by Meteorological Foundation of China (GYHY201006038),by the Priority Academic Program Development of the Jiangsu Higher Education Institutions (PAPD).We thank the two anonymous reviewers for their constructive comments and suggestions,which greatly improved the manuscript.
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法国葡萄酒主要葡萄品种介绍
法国葡萄酒主要葡萄品种介绍 贝露娃（中国称呼为黑比诺）- Pinot Noir 贝露娃是名贵红酒用葡萄的皇后。其酒体温柔清雅，其特点是年轻时清雅芳香，成熟时温柔雅致，果味充盈而复合，并带有较明显的草莓和樱桃的香气。贝露娃可以酿出全世界最令人兴奋的红酒，但美玉有瑕，贝露娃是公认难以栽植的葡萄品种，其果粒虽成熟较早，但脆弱、皮薄、易腐烂。 嘉本纳沙威浓（民国时期开始，中国人也称为赤霞珠）- Cabernet Sauvignon 嘉本纳沙威浓是高贵的红酒葡萄品种之王，在全世界广为种植。其颗粒小、皮厚、晚熟，酿成的酒色泽深浓。葡萄酒浅嫩时单宁酸味激烈，有藏酿之质。其特点是最能表现黑加仑子味，蜜瓜味、甘草味，酒体结构丰厚结实，酒力强劲。
上图为嘉本纳沙威浓（也称为赤霞珠Cabernet Sauvignon） 穗乐仙- Shiraz( Syrah ) 穗乐仙是古典红酒用葡萄中的王子。属中浓度酒体,在嘉本纳沙威浓与贝露娃之间，具藏酿价值。完全成熟时，如上等贝露娃一样质地柔滑而浓郁。穗乐仙是一种晚熟品种，色泽较深，在温暖的土质如花岗岩土壤中生长最佳。但如种植过密，它所特有的桑椹果香和黑胡椒味就会变淡。 上图为穗乐仙，也称为设拉子-Shiraz（Syrah） 梅乐- Merlot 梅乐也是最受欢迎的红葡萄品种。梅乐之所以受欢迎是因为它早熟、鲜嫩且多产，可以用来大量酿制美味而柔滑的葡萄酒。也可以广泛用作与其它葡萄品种混合成成熟平衡的红酒。梅乐在较凉的地方长势良好。
上图为梅乐（Merlot） 佳美- Gamay 佳美原产自法国布根地，现在主要产于宝祖利村。所产葡萄酒颜色呈淡紫红色，单宁含量非常低，口感清淡，富含新鲜果香。用佳美酿制的葡萄酒简单易饮，通常不适宜久存，属于酒龄年轻时饮用的葡萄酒。但若生长在火成页岩、石灰含量少的土质上，佳美也能生产出丰厚浓郁耐久存的红酒，如几个宝祖利村的特级产区Moulin-a-Vent、St. Amour等等。除宝祖利村之外，以卢雅雨河谷种植最多。至于加州产的Gamay Beaujolais是贝露娃（Pinot Noir)的一种，并非真正的佳美种。 添帕尼优- Tempranillo 添帕尼优原产于西班牙北部，字源学上意指“早熟”之意。贫瘠坡地的石灰黏土是其最佳的种植条件，不同于其它西班牙品种，适合较凉爽温和的气候。添帕尼优是里奥哈最重要的品种，主要种植于上里奥哈Rioja Alta和Rioja Alavesa，另外在西班牙北部也普遍种植，但在他国并不著名。添帕尼优的品质不差，酸度不足是其常有的缺点，酿酒有时与其它葡
葡萄品种介绍
葡萄品种介绍 葡萄品种Chardonnay霞多丽Sauvignon Blanc 长相思 葡 萄 园 中 葡萄特征果粒大，呈黄色，边缘带棕色斑点 萌芽早，早熟，有高糖潜力（高酒精度），容 易种植，适应能力强，产量高 中等大小果粒，果串紧凑（不通风，容易霜霉菌）， 高酸度，萌芽晚，早熟，特别茂盛。 容易感染白粉霉，霜冻，晚季时酸度下降孢菌，白粉霉，黑霉 气候适合多种气候，在温暖环境中会成熟过快适应凉爽气候 土壤适合多种土壤，最适合石灰质土壤（碱性土 壤），石灰石，白垩土，砂石。 不适合潮湿或肥沃的土壤 白垩土，沙烁，粘土，燧石（火石），泥灰土 酒 厂 中 苹果酸乳酸 发酵 被广泛应用，添加黄油质感，奶油未：保持清爽的酸度和辛辣的香味（植物香气） 发酵：口感柔和（西班牙，智利）调配调配：添加塞美容，柔和口感和增添香味（波尔 多产区，有很强的陈年能力）橡木熟成与橡木接触，加深颜色，带有烤面包木材味添加烤面包的风味，使香气变得柔和。 塞美容Semillon+长相思 惰性容器熟 成 保留矿物质和水果特征保持新鲜的香气 窖藏能力大部分出厂后饮用，顶级酒可窖藏10+年大部分年轻时饮用苏玳出产的可窖藏数几十年。 主要著名产区法国勃艮第（夏布利Chablis，默尔索 Meursault，布衣富塞Pouill-Fuisse），香槟产区 Champagne 法国卢瓦尔河（桑塞尔Sancerre，布衣富美 Pouillu-Fume）清爽，无橡木风格。 法国波尔多（苏玳Sauternes）贵腐甜酒。经常与 塞美容调配，橡木风格 美国加州California：浓郁，橡木风格 澳大利亚Australia：热带水果，橡木风格 新西兰（马尔伯勒Mrlborough）清爽，无橡木风 格。 智利Chile，阿根廷Argentina，新西兰New Zealand，南非South Africa，俄勒冈州Oregon 智力：非常辛辣的香气 加州：有时候标为：Fume Blanc 南非South Africa，澳大利亚Australia 外观 Appearance 中等稻草黄/绿色 中等到深金/黄色(用过橡木桶) 浅等稻草黄/绿色
1、公司及产品介绍●
一、公司介绍 XX幸福缘农业生产开发XX于2009年9月正式成立，是XX灾后一个新型的，健康的农业项目，是利国利民的绿色项目。公司的所在地仁寿县曹家镇地理位置特殊，资源丰富，被誉为“中国枇杷之乡”、“中国百年梨乡”。公司通过农业产业化经营建立的无公害产品基地，坚持实施土壤改良、品种优化为方针，整个生产过程中不施用农药、化肥、不使用除草剂，被XX市定点为绿色食品配送基地。公司现有研发、种植等科技示X园区一万多亩，原料供应保障基地五万多亩，并将在政府的扶持下三年内大规模的扩充原料保障种植基地。公司的前景： 第一、顺应天意（天时） 我们国家提倡绿色生态，低碳生活，号召我们吃绿色产品，享受健康，而且国家对农业这方面投资力度非常大，特别是XX灾区，地震灾后，国家政策大力倾斜灾区，灾后重建家园，在国家和政府的大力支持下，许多专家踊跃参加灾区建设，我们公司在这个好的政策下，根据营养免疫学专家陈昭妃博士的理论和营养专家的指导下，根据当地的自然资源，科学合理的配方，通过物理冷冻加工的方式，配置了两款产品，营养餐和福缘茶。 第二、自然资源丰富（地利） XX仁寿地处XX大山环抱的山区，自然环境非常好，天然的自然资源，充足了阳光，清泉的河流，沐浴着仁寿的整个现场，到处是绿色，没有任何污染，没有污染企业，大山上都是天然的魔芋产地，到处是葛根，特别是金花梨香脆可口，营养丰富，自然资源非常丰富，公司陈总在专家的精心指导下，充分利用当地的自然资源，建立幸福缘食品加工厂，生产出幸福缘营养餐和福缘茶。 第三、人性化的制度（人和） 公司领导，为了把我们的产品广泛的宣传出去，就把做广告的钱直接或间接返给大家，也就是说让有钱的没钱的都能吃到绿色的、营养丰富的、低廉的产品，所以公司在三年时间内做了一个人性化的制度，就是谁吃我们产品，谁就有资格得到公司的奖金，只要一次性购买公司11盒产品，就能得到公司每个月300元的补助，或者累计达到11盒产品，同样得到公司的补助，这样一来，有钱的能吃到我们这么好的产品，没钱的也能吃到。 公司：.zgxfy.
常用网络设备设备
物理层设备 1.调制解调器 调制解调器的英文名称为modem，来源于Modulator/Demodulator，即调制器/解调器。 ⑴工作原理 调制解调器是由调制器与解调器组合而成的，故称为调制解调器。调制器的基本职能就是把从终端设备和计算机送出的数字信号转变成适合在电话线、有线电视线等模拟信道上传输的模拟信号；解调器的基本职能是将从模拟信道上接收到的模拟信号恢复成数字信号，交给终端计算机处理。 ⑵调制与解调方式 调制，有模拟调制和数字调制之分。模拟调制是对载波信号的参量进行连续地估值；而数字调制使用载波信号的某些离散状态来表征所传送的信息，在接收端对载波信号的离散参量进行检测。调制是指利用载波信号的一个或几个参数的变化来表示数字信号的一种过程。 调制方式相应的有：调幅、调频和调相三种基本方式。 调幅：振幅调制其载波信号将随着调制信号的振幅而变化。 调频：载波信号的频率随着调制信号而改变。 调相：相位调制有两相调制、四相调制和八相调制几种方式。 ⑶调制解调器的分类 按安装位置：调解解调器可以分为内置式和外置式 按传输速率分类：低速调制解调器，其传输速率在9600bps以下；中速调制解调器，其传输速率在9.6～19.2kbps之间；高速调制解调器，传输速率达到19.2～56kbps。 ⑷调制解调器的功能 ?差错控制功能：差错控制为了克服线路传输中出现的数据差错，实现调制解调器至远端调制解调器的无差错数据传送。 ?数据压缩功能：数据压缩功能是为了提高线路传输中的数据吞吐率，使数据更快地传送至对方。 ⑸调制解调器的安装 调制解调器的安装由两部分组成，线路的连接和驱动程序的安装。 线路连接： ?将电话线引线的一端插头插入调制解调器后面LINE端口。
关于葡萄的营养价值介绍
关于葡萄的营养价值介绍 1.葡萄的营养价值很高，葡萄汁被科学家誉为“植物奶”。葡萄含糖量达8%～10%，以葡萄糖为主。在葡萄所含的较多的糖分中，大部分是容易被人体直接吸收的葡萄糖，所以葡萄成为消化能力较弱者的理想果品 2.葡萄中含有矿物质钙、钾、磷、铁以及多种维生素B1、B2、B6、C和P等，还含有多种人体所需的氨基酸。 3.葡萄中含较多酒石酸。 4.葡萄干含水量较低，约17%，糖和铁的含量均相对增加，是儿童、妇女和体虚贫血者的滋补佳品。葡萄中大部分营养在葡萄干中被浓缩。 5.葡萄籽95%的成份为原青花素其抗氧化的功效比维生素C高出18倍之多，比维生素E高出50倍。 1、有很多时候，腹泻的原因是食用完葡萄就立即饮用水。葡萄本身就是一种通便润肠的食物，吃完后即刻喝水，葡萄在胃中还没有消化吸收，水就稀释了胃酸。葡萄、水、胃酸搅拌在一起，立刻氧化发酵，使肠道加快活动，导致腹泻的结果。因为这种腹泻是食物引起来的，所以，泻完之后，人体就会恢复，不会有大问题出现。 2、不能在吃完葡萄后即刻饮用牛奶。葡萄中富含维C，而牛奶中的某种物质会和维C 发生化学反应，对胃的伤害是极其明显的，轻时会产生腹泻，重则会上吐下泻。因此，葡萄和牛奶不可同时食用。 3、在吃完葡萄后，最少要在4小时之后再吃海鲜类产品，谨防两种食物中的物质相互反应，影响健康。 4、食用葡萄的量是要有限制的，不可以过多。葡萄中有极其丰富的营养物质，是水果中的皇者。它的身体里有游离水、胶体结合水、生命水，还有很多糖类、有机酸和矿物质、氨基酸等，这些，都是人体必需的营养物质。 1、清除自由基、抗衰老、增强免疫力 清除自由基，阻止自由基对人体细胞的破坏。保护人体器官和组织，防治心脏病、癌症、早衰、糖尿病、动脉硬化等100多种由自由基所引起的疾病。 2、保护皮肤、美容养颜 有“皮肤维他命”和“口服化妆品”的美誉，保护胶原蛋白，改善皮肤弹性与光泽，美白、保湿、祛斑;减少皱纹、保持皮肤的柔润光滑;清除痤疮、愈合疤痕。
最新整理初一介绍葡萄的说明文范文3篇
最新整理初一介绍葡萄的说明文范文3篇范文一 我家院子里种了一株葡萄。前几天，我和妈妈给葡萄搭了一个大架子，又给它施了许多肥。去年冬天，葡萄枯死了，就剩下一条长长的老藤，我想把它挖出来，妈妈说：“等天明年春天，葡萄就会发出新芽，长出嫩绿的叶子。”春天，春姐姐给葡萄披上了绿色的衣裳，葡萄藤发芽了，长出了嫩绿的叶子。春风轻轻地吹着，葡萄叶在春风的吹动下像一双小手摇摇摆摆。四月份，葡萄开出一串串的白花，像一团团雪花，美丽极了。爸爸说：“葡萄开过花后就会长出一串串葡萄。”我每天都要到院子里观察葡萄。不过多久，葡萄长出来了！“一串、二串、三串、四串……”我认真地数着。葡萄圆圆的，和桂圆一样大小，葡萄的表皮先是青的，再变成紫色，葡萄就长成熟了。 收下葡萄，我津津有味品尝着，剥开表皮，就会看见淡青色的果肉，它的果肉又酸又甜，非常好吃。吃着吃着，我想起了我小时候吃葡萄的故事。 有一次，妈妈去买菜，我在家里一边看动画片一边吃葡萄。突然，我不小心把葡萄籽吞进了肚子里，我看见电视机上的小朋友也把西瓜籽吞进了肚子里，不久就长出了西瓜。我想：“我的肚子里会不会长出葡萄？”我越想越怕。突然，我想了一个好办法，喝多一些水，想把它淹死。于是我一口气喝了十多杯水，肚子胀得要命。妈妈回来了，我把事情的经过告诉了妈妈，弄得妈妈哭笑不得，说：“肚子里没有阳光，没有土壤，葡萄怎么会生长呢？”听了妈妈的话，我才松了口气。每当想起这个往事时，我就会哈哈大笑起来。 我爱葡萄，它不仅好吃，还具有顽强的生命力。
范文二 我家有一棵葡萄树，他已经在我家生活了3年了，我非常喜欢他，我每天给他浇水，因此，它在我们家茁壮成长。 春天，是万物复苏的季节。葡萄树一身绿叶，仿佛穿上了一件天然纯绿色的衣衫。远处与近处的效果决然不同，远看，葡萄树像一个坚守岗位的战士，而近看，它在阳光的照耀下又向一个美丽的精灵。 夏天，天气十分炎热，而在葡萄树下却感觉不到炎热，扑鼻传来阴凉的气息。这个季节，是葡萄树生长最旺盛的季节，葡萄树的叶子越来越茂盛了。而葡萄树也长出了新的果实，但这果实呈淡绿色，有一点偏黄，剥开绿皮，有一团绿色的果肉，酸酸的，可以让你“酸掉牙”。当然，没有尝试过的人不知道他的滋味，但这也是可以令你欣慰的。 秋天，是成熟的季节，是植物收成的季节。葡萄树的叶子开始凋落，但果实变成了黑紫色，这时的葡萄才是成熟的葡萄。剥开紫色的皮，有一团黑色的果肉，一口吞掉它。（要注意有葡萄里有小籽，千万不要全吞，要吐出小籽）。吃着美味的葡萄，我的心里甜滋滋的，这时我也感受到了丰收的喜悦，感受到了农民伯伯们的辛苦。 冬天，葡萄树的叶子全凋落了，只剩下枝条和枝干，但它也像梅花一样不惧严寒，也像冬眠动物们一样轻轻睡着了，等待这春妈妈把它“叫醒”。 这就是我家的葡萄树。
葡萄说明文
小学作文范文五年级第三单元学写说明文。介绍一种水果 我最喜欢的水果-----草莓 说起水果，我就会不由自主地高兴起来，因为从小我就非常喜欢吃水果，像西瓜呀、桃呀、葡萄和苹果等等，有的时候我饭吃得不多，但是每天我都要吃很多的水果，家长还老说我是吃水 果长大的漂亮的女儿呢。 在我爱吃的水果当中，草莓是我的爱，因为它不仅成熟早，可以在所有瓜果中率先上市，而且新鲜味美，酸味不大，甜味清淡， 酸甜可口，还不伤肠胃。 为了了解草莓是怎样生长的，我还专门上网查看了很多草莓的资料呢，从中我知道了草莓属蔷薇科多年生草本植物，又叫洋莓，原产于南美洲。草莓品种繁多，有2000多个品种。草莓喜欢温暖的天气，不耐寒冷。我国的河北省、山东省和很多南方省市都有草莓的种植。 草莓的果实是球形或椭圆球形。成熟的果实红艳艳的，表面疙疙瘩瘩,附有许多小种子，小时候我还以为那是很多的芝麻粘在上面呢。草莓的果实鲜艳红嫩,柔软多汁,甜酸可口，含有丰富的维生素c，此外还含胡萝卜素、多种维生素、葡萄糖、蛋白质、脂肪、铁钙、磷等，所以有人管草莓又叫“美容果”，拿起一个放到口中轻轻的嚼动，那粉红色的汁液伴随着鲜嫩的果肉在嘴里有一种甜滋滋、酸溜溜、凉爽爽的美妙感觉，唯一感到遗憾的就是那附在草莓表面上的小种子吃起来没有什么味道。 每当家长买回草莓的时候，只要我有时间，我都要亲手把草莓下面的绿叶摘下来，如果叶子是水灵灵鲜绿色的，那么草莓一定是新鲜的，我真希望有机会去种植草莓的地方亲眼看看草莓是怎样 生长的。 我还有很多种吃草莓的方法呢，有的是家长告诉我的，有的是我自己发明的，比如：把草莓洗净用小刀切成四块放入盘中，在上面洒上一点白糖，这样吃起来就算是不太熟的草莓，也不会感到很酸了。还可以把切好的草莓和切好的黄瓜和小西红柿放在一起，放入沙拉酱拌好，就成了一道美味的水果沙拉了。 总之，草莓是我非常喜欢吃的水果之一，虽然写了这么多，但好 像我还是有点意犹未尽。 ....那个，自己加一点呗 葡萄（谢成斌） 葡萄是一种像徽章大小的水果，外形可爱，味道可口，是世 界上最古老的植物之一。 葡萄原产于欧洲，西亚和北非一带。据考古资料显示，最早栽培葡萄的地区是小亚细亚里海和黑海之间及其南岸地区。大约 在7000年以前，南高加索、中亚细亚、叙利亚、伊拉克等地区也开始了葡萄的栽培。希腊是欧洲最早开始种植葡萄并进行葡萄 酒酿造的国家。 葡萄在我国长江流域以北各地均有，主要产于新疆、甘肃、山西、河北、山东等地。葡萄茎长达10米到20米。花很小， 是黄绿色的。 葡萄有很多种类，有白、青、红、褐、紫、黑等不同果色。果熟期8到10月，中国栽培葡萄已有2000多年历史，相传为 汉代人张骞引入。
无线网络工作原理剖析
无线网络工作原理 概念 科技的飞速发展，信息时代的网络互联已不再是简单地将计算机以物理的方式连接起来，取而代之的是合理地规划及设计整个网络体系、充分利用现有的各种资源，建立遵循标准的高效可靠、同时具备扩充性的网络系统。无线网络的诸多特性，正好符合了这一需求。 一般而言，凡采用无线传输的计算机网络都可称为无线网。从WLAN到蓝牙、从红外线到移动通信，所有的这一切都是无线网络的应用典范。就本文的主角——WLAN 而言，从其定义上可以看到，它是一种能让计算机在无线基站覆盖范围内的任何地点（包括户内户外）发送、接收数据的局域网形式，说得通俗点，就是局域网的无线连接形式。 接着，让我们来认识一下Wi-Fi。就目前的情况来看，Wi-Fi已被公认为WLAN的代名词。但要注意的是，这二者之间有着根本的差异：Wi-Fi是一种无线局域网产品的认证标准；而WLAN则是无线局域网的技术标准，二者都保持着同步更新的状态。 Wi-Fi的英文全称为“Wireless Fidelity”，即“无线相容性认证”。之所以说它是一种认证标准，是因为它并不是只针对某一WLAN规范的技术标准。例如，IEEE 802.11b是较早出台的无线局域网技术标准，因此当时人们就把IEEE 802.11b标准等同于Wi-Fi。但随着无线技术标准的多样
化，Wi-Fi的内涵也就相应地发生了变化，因为它针对的是整个WLAN领域。 由于无线技术标准的多样化出现，所使频段和调频方式的不尽相同，造成了各种标准的无线网络设备互不兼容，这就给无线接入技术的发展带来了相当大的不确定因素。为此。1999年8月组建的WECA（无线以太网兼容性联盟）推出了Wi-Fi标准，以此来统一和规范整个无线网络市场的产品认证。只有通过了WECA认证，厂家生产的无线产品才能使用Wi-Fi认证商标，有了Wi-Fi认证，一切兼容性问题就变得简单起来。用户只需认准Wi-Fi标签，便可保证他们所购买的无线AP、无线网卡等无线周边设备能够很好地协同工作。 原理 尽管各类无线网所遵循的标准和规范有所不同，但就其传输方式来看则不外两种，即无线电波方式和红外线方式。其中红外线传输方式是目前应用最广泛的一种无线网技术，我们所使用的家电遥控器几乎都是采用红外线传输技术。作为一种无线局域网的传输方式，红外线传输的最大优点是不受无线电波的干扰，而且红外线的使用也不会被国家无线电管理委员会加以限制。然而，红外线传输方式的传输质量受距离的影响非常大，并且红外线对非透明物体的穿透性也非常差，这就直接导致了红外线传输技术与计算机无线网的“主角地位”无缘；相比之下，无线电波传输方式的应用则广泛得多。基于本文的定位，在此笔者仅简单介绍无线电波的调制方式。
葡萄的基本介绍
葡萄的基本介绍 在西方古老的传说中，葡萄果实是由乐善好施的神Osiris把它带到人间来的，葡萄酒“Vi n"一词，其实就是人们心中“神”的另一种说法。葡萄属落叶藤本植物，葡萄科植物葡萄的果实，是地球上最古老的植物之一，也是人类最早栽培的果树之一。大约在100万年以前，葡萄树就在地中海沿岸自然地生长着，法国南部阳光充沛的普罗旺斯地区就是葡萄的起源地，并从这里开始向东西方传播。在中国，葡萄是由汉朝张骞在公元前138年出使西域时从波斯引进的，后来经丝绸之路把这个绿色使者引向了不毛之地的戈壁。如今在全世界的果品生产中，葡萄的产量及栽培面积一直居于首位，成为人们心中真正的“水果之神”。 世界各地生产的葡萄有上千种，总体上可以分为酿酒葡萄和食用葡萄两大类： 酿酒葡萄可以分为酿造白葡萄酒、酿造红葡萄酒和调色调香三大品种，这些葡萄的主要产区分布在法国南部、意大利东部、美国加洲和南美洲各国。 食用葡萄的品种更加繁多，市场上常见的巨峰、龙眼、玫瑰香等品种都是物美价廉的食用葡萄，而闻名中外的我国新疆马奶葡萄、河北白牛奶葡萄、山东龙眼葡萄以及四川的绿葡萄则都是口感甘甜、营养丰富的葡萄佳品。一般来说，食用葡萄生长地区的日照越充足、气候越干燥、早晚温差越大，则果实越饱满、口味越浓郁、营养价值越高。葡萄与提子实质上都是葡萄的果实。“提子”是香港等地对葡萄的别称。 葡萄的功效与作用 1.缓解低血糖 葡萄中的糖主要是葡萄糖，能很快的被人体吸收。当人体出现低血糖时，若及时饮用葡萄汁，可很快使症状缓解。 2.预防血栓 法国科学家研究发现，葡萄能比阿斯匹林更好地阻止血栓形成，并且能降低人体血清胆固醇水平，降低血小板的凝聚力，对预防心脑血管病有一定作用。 3.抗衰老 葡萄籽可说是真正的抗氧化巨星。抗氧化是抗老化的方法，因此，葡萄籽能抗衰老，并可清除体内自由基，让您永葆青春。 4.有助康复 葡萄中含有一种抗癌微量元素(白藜芦醇)，可以防止健康细胞癌变，阻止癌细胞扩散。葡萄汁可以帮助器官植手术患者减少排异反应，促进早日康复。 5.健脾和胃 有助于消化，适当多吃些葡萄，能健脾和胃。 6.缓解疲劳 对神经衰弱、疲劳过度大有裨益。 葡萄的营养价值 1.葡萄的营养价值很高，葡萄汁被科学家誉为“植物奶”。葡萄含糖量达8%～10%，以葡萄糖为主。在葡萄所含的较多的糖分中，大部分是容易被人体直接吸收的葡萄糖，所以葡萄成为消化能力较弱者的理想果品 2.葡萄中含有矿物质钙、钾、磷、铁以及多种维生素B1、B2、B6、C和P等，还含有多种人体所需的氨基酸。
网络通信的工作原理 教案课程
第三章第二节 课题：3.2 网络通信的工作原理 教学目标：1.了解OSI模型中的各个层次；2.了解TCP/IP协议在OSI模型的位置； 3.了解数据交换技术的电路交换、报文交换、分组交换的工作原理，能进行不同的数据交换技术比较； 4.使用数据交换技术的电路交换、报文交换、分组交换的工作原理解释生活中技术问题，培养学生探究能力，合作能力、观察能力； 5.通过体验、感悟电路交换、报文交换、分组交换的工作原理的学习过程，体验技术发展的过程和思维，体验突破技术，改造技术、创新技术的成就感。 教学重点：OSI模型的理解、TCP/IP协议的重要地位、电路交换、报文交换、分组交换三者的特点与区别 教学难点：OSI模型的理解 课时安排：2课时 教学方法：演示法，讲授法，任务驱动法 教学过程： 第一课时：数据传输过程 一、OSI参考模型 1、很多同学都非常喜欢玩网络游戏，比如魔兽世界，梦幻西游。不知道同学们想不想了解这些网络游戏在网上的一个工作原理，了解游戏是如何在网上运作的。 2、在了解游戏之前，我们先来看看现实生活中的邮政系统，参照这个邮政系统能加快我们对网络游戏的一个理解。课本上的P55页上3.2.1数据传输过程中，图3-3 邮政系统的分层模型。大家可以想象一下我们平时的写信寄信的一个过程。
首先我们写好信后，要让这封信能寄出去，我们就得贴邮票。而邮票，就是我们和邮政局的约定，我交8毛钱给你邮政局，那么你要负责帮我把信送到。而邮政局呢，也和运输部门有个类似的约定。通过这一系列的约定，我们可以保证我们所写的信能送到我们想要送到的目的地。但是这里注意一个问题：邮票做为约定不是一成不变的。比如说，刚刚解放前，也许送信只需要几分前。而现在人民的生活富裕了，相应的，一封信是8毛钱。也就是说，协议，或者约定完全是按照当时的情况做出的适当的处理。如果情况出现变化，协议一样可以随着情况而做出改变。 3、实际上，网络上数据的传输过程和现实中是非常类似的，我们可以来想象一下： 我现在有一批水果，准备运到罗马。如果我想实现这个目标，我需要什么条件？ （1）首先我要有一条路，不管是马路还是铁路，这条路要能从出发点连接到目标点。 （2）路是有了，我要保证这条路是通畅的，不能说走进死胡同，我要保证这条路能够通车，假设我是用火车来运的话，不会出现半路出轨的现象（3）路永远不会只有一条。条条道路通罗马，那么，我要保证我要走的道路能最快，最省钱的到达目的地。因此，我要选择一条近路。 路已经有了，基本条件已经具备，我们现在可以开始送东西了，但是是不是有了路就万无一失了。我们还需要有什么？ （4）路是有了，我们现在坐火车把东西送过去，结果送到半中间被强盗打劫了，或者是被人偷了，所以我们要保证在送过去的途中要原封不动的送到，少一
7.常见的葡萄品种介绍
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(设备管理)VIP基本原理与常见设备
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红葡萄酒。这类酒的色泽应该是桃红色、或玫瑰红、淡红色。 葡萄酒按含二氧化碳压力分类 平静葡萄酒也称静止葡萄酒或静酒，是指不含二氧化碳或很少含二氧化碳（在20℃时二氧化碳的压力小于0.05MPa）的葡萄酒。 起泡葡萄酒葡萄酒经密闭二次发酵产生二氧化碳，在20℃时二氧化碳的压力大于或等于0.35MPa。 加气起泡葡萄酒也称为葡萄汽酒，是指由人工添加了二氧化碳的葡萄酒，在20℃时二氧化碳的压力大于或等于0.35MPa。 葡萄酒按含糖量分类 A．对于平静葡萄酒 干葡萄酒干葡萄酒是指含糖量（以葡萄糖计，下同）小于或等于4.0g/L 的葡萄酒。由于颜色的不同，又分为干红葡萄酒、干白葡萄酒、干桃红葡萄酒。 半干葡萄酒半干葡萄酒是指含糖量4.1～12.0g/L的葡萄酒。由于颜色的不同，又分为半干红葡萄酒、半干白葡萄酒、半干桃红葡萄酒。 半甜葡萄酒半甜葡萄酒是指含糖量12.1～50.0g/L的葡萄酒。由于颜色的不同，又分为半甜红葡萄酒、半甜白葡萄酒、半甜桃红葡萄酒。 甜葡萄酒甜葡萄酒是指含糖量大于或等于50.1g/L的葡萄酒。由于颜色的不同，又分为甜红葡萄酒、甜白葡萄酒、甜桃红葡萄酒。 B．对于起泡葡萄酒 天然起泡葡萄酒含糖量小于或等于12.0g/L的起泡葡萄酒。 绝干起泡葡萄酒含糖量12.1～20.0g/L的起泡葡萄酒。 干起泡葡萄酒含糖量20.1～35.0g/L的起泡葡萄酒。 半干起泡葡萄酒含糖量35.1～50.0g/L的起泡葡萄酒。 甜起泡葡萄酒含糖量大于或等于50.1g/L的起泡葡萄酒。 葡萄酒按酿造方法分类 A．天然葡萄酒完全用葡萄为原料发酵而成，不添加糖分、酒精及香料的葡萄酒。 B．特种葡萄酒特种葡萄酒是指用新鲜葡萄或葡萄汁在采摘或酿造工艺中使用特种方法酿成的葡萄酒。 利口葡萄酒在天然葡萄酒中加入白兰地、食用精馏酒精或葡萄酒精、浓缩葡萄汁等，酒精度在15％～22％的葡萄酒。 加香葡萄酒以葡萄原酒为酒基，经浸泡芳香植物或加入芳香植物的浸出液（或蒸馏液）而制成的葡萄酒。 冰葡萄酒将葡萄推迟采收，当气温低于-7℃，使葡萄在树体上保持一定时间，
葡萄基本知识介绍
南方葡萄的栽培技术与投资效益分析 葡萄为葡萄科植物葡萄的果实。原产西亚，在我国长江流域南北各地均有产，主要产于新疆、甘肃、山西、河北等地。 葡萄品种很多，根据其原产地不同，分为欧美品种和欧亚品种。每年6～10月果实成熟时采摘. 1、葡萄是见效最快的果树之一，具有高产、稳产等优势，在正常管理条件下，一般无大小年现象，产量相当稳定。葡萄的种植效益较为可观。葡萄生育期150天—160天左右（育苗需30-40天左右），葡萄的寿命和经济栽培年限一般可达３０到５０年。 2、葡萄的作用：葡萄果色鲜艳，汁多味美； 营养丰富：它含糖量高，还含有机酸，蛋白质，无机盐，并含有多种的维生素，和人体所需的氨基酸；葡萄除可制葡萄干和葡萄汁以外，也可酿酒；制罐头与果酱；美化、遮荫：在住家顶楼平台种植葡萄既可美化楼顶。 葡萄营养分析： 1.葡萄中的糖主要是葡萄糖，能很快的被人体吸收。当人体出现低血糖时，若及时饮用葡萄汁，可很快使症状缓解； 2.科学家研究发现，葡萄能比阿斯匹林更好地阻止血栓形成，并且能降低人体血清胆固醇水平，降低血小板的凝聚力，对预防心脑血管病有一定作用； 3.葡萄中含的类黄酮是一种强力抗氧化剂，可抗衰老，并可清除体内自由基； 4.葡萄中含有一种抗癌微量元素，可以防止健康细胞癌变，阻止癌细胞扩散。葡萄汁可以帮助器官植手术患者减少排异反应，促进早日康复。 1. 葡萄避雨栽培技术 葡萄避雨栽培技术 避雨栽培是以防止和减轻葡萄病害发生，提高葡萄品质和生产效益为主要目的一种栽培技术。主要做法是：在葡萄的生长季节用塑料大棚将葡萄扣起来，或在葡萄树冠顶部用简易的塑料棚架覆盖起来，使葡萄株蔓、花果处于避雨状态，从而防止和减轻葡萄病害发生。我国是典型的大陆季风气候，冬季干寒多风、夏秋季多雨，给葡萄生产带来很多不利因素，尤其长江以南地区雨水丰沛，特别是在新梢生长、开花座果期间正值梅雨季节，高温高湿的气候条件极易使露地栽培葡萄发生较为严重的葡萄病害。避雨栽培，让葡萄枝叶能很好地避开自然降雨，可大大减轻因雨水飞溅多种病害的侵染，如白腐病、炭疽病、霜霉病等；同时，可以减少农药使用量，提高葡萄的安全质量，确保生产出无公害、绿色葡萄。因此，推广葡萄的避雨栽培技术具有重要意义和作用。近几年来，该项技术在我省得到了较快地推广。为了进一步推广该项技术，我们将该技术的几个关键性的技术整理如下，供大家参考。 一、避雨设施的构建 避雨设施的构建，根据各种植企业、农户的经济条件决定。一般分三种构：
公司产品介绍与工作中相关注意事项
公司产品介绍和工作中相关注意事项制作：刘宁（制造一部）日期：2006-05-31 一、公司主要产品为各类可充电电池和充电器产品。主要有以下几大类： 1、記本電腦電池塊 2、攝錄機電池塊 3、數碼相機電池塊 4、電鑽機電池塊 5、手機電池塊 6、外置電池包 7、專業攝錄機電池塊 8、手寫電腦電池塊 9、MP3、MP4、扫描仪等内置电池块 10、各类充电器 11、开关电源 二、所使用的电池粒的分类： (1).锂离子电池粒 Lithium-ion cell=Li-ion (2).镍氢电池粒 Nickel Metal-hydrogen cell=Ni-MH (3).镍镉电池粒 Nickel-Cadmium cell=Ni-CD （4）. 產品名稱的命名規則： 3.1、CL/CB产品介绍和生产注意事项： 1、此类产品的线路板较复杂，表面元件较多，生产时应注意到下事项： A、部分产品的线路板共用，外形完全相同，只是内部烧写的程式不同。在产前注意确认品保部LQC做的相关标识 （ CL507和508、CL51和CL52等）。 B、连接电池与PCM 的焊接作业时必需从低电位到高电位，反之则会造成线路板损坏或内部程序错误 C、同时在焊接时一定不可以焊错，尤其是不可以漏焊中间端的焊点（例如标“T2、T3、T4”字样的焊接位置），由于若 漏焊则亦可以通过LQC的测试架测试，但却不能正常使用 D、在装线路板和焊接过程中一定不可以造成任何短路，否则会造成元件损坏。 3.2、pl/pb普通电产品介绍和生产注意事项 A、采用普通的保护芯片（如S8232、MM1292、S8231、S8234、FTD2210、TPC8208、F2450等）组成的电池充放电保护。功能单一，线路较简单。在焊接作业时需注意元件的安装方向和焊接质量 B、分线路板五金部分为外漏（主要是一些数码相机电池）在生产PCM时需在贴装前注意抽查，装配时需注意过程的防护 （如打电工序、焊接线路板工序、清洗工序等）时注意检查外观，清洁、有无刮花、生锈等不良； C、部分产品为内置型（电池全部放入原装机内则为内置），对于尺寸要求较高。在生产时需注意产品内部的清洁和其它特别工序的作业标准有没有完全落实并达成。 D、PLX系列产品为在装配时小电池使用大胶壳生产，如PLX408就是使用PL416的胶壳生产，其它方面相同； E、PB系列产品使用镍氢、镍铬电池粒，不加保护电路。生产时需特别注意打电、备电池、装压五金片、合壳工序，这些工序最容易产生不良。 3.3、PL聪明电产品介绍和生产注意事项 A、此类产品的线路板较复杂，除具有基本的保护功能外均有软件程式于MCU或EEPROM内，为智能电池。在生产中要特别注意静电防护和焊接的顺序，以确保内部程式的完整性。
网络设备与调试-交换机的管理方式和工作原理
第十九课时 教学内容： 交换机的管理方式和工作原理 教学目的： 1. 掌握交换机的管理方式。 2. 掌握交换机的工作原理。 教学重难点： 1. 掌握交换机的管理方式。 2. 掌握交换机的工作原理。 教学方法： 讲授法、 教学学法： 接受法、 教学过程 一、引入 在上一节课我们了解了超级终端软件的使用，超级终端来调试配置交换机，这其实是一种交换机管理方式，那么交换机有哪些管理方式呢？ 二、新课 <一> 交换机的管理方式 不可网管交换机 telnet 拨号管理 交换机分为带内管理网管软件管理（不需要配置线） 网络浏览器（必须有可视化窗口） 可网管交换机带外管理： console口的软件管理管理
1. 交换机管理的管理指：通过管理端口执行监控交换机端口、划分vlan、设置trunk端口等管理功能。 2. 可管理的交换机都具有console口。 3. 可网管交换机还可以通过网络浏览器或telnet管理，但是必须给交换机指定一个ip地址，这个ip地址除了供管理交换机使用之外，没有其他用途。带内管理交换机，则交换机都必须要有一个ip地址。 NVRAM：非易失性随机访问存储器，指断电后数据不丢失的一种ram。 4. 可网管交换机均遵循snmp（简单网络管理协议），snmp协议是一整套的符合国际标准的网络设备管理协议，可以通过网管软件管理。是一种带内管理。 <二> 交换机的工作原理 1．端口交换 端口交换技术最早出现在插槽式的集线器中，这类集线器的背板通常划分有多条以太网段（每条网段为一个广播域），不用网桥或路由连接，网络之间是互不相通的。以大主模块插入后通常被分配到某个背板的网段上，端口交换用于将以太模块的端口在背板的多个网段之间进行分配、平衡。根据支持的程度，端口交换还可细分为： ·模块交换：将整个模块进行网段迁移。 ·端口组交换：通常模块上的端口被划分为若干组，每组端口允许进行网段迁移。 ·端口级交换：支持每个端口在不同网段之间进行迁移。这种交换技术是基于OSI第一层上完成的，具有灵活性和负载平衡能力等优点。如果配置得当，那么还可以在一定程度进行客错，但没有改变共享传输介质的特点，自而未能称之为真正的交换。 2．帧交换 帧包括三部分：帧头，数据部分，帧尾。其中，帧头和帧尾包含一些必要得控制信息，比如同步信息、地址信息、差错控制信息等；数据部分则包含网络层传下来的数据，比如ip数据包。 帧交换是目前应用最广的局域网交换技术，它通过对传统传输媒介进行微分段，提供并行传送的机制，以减小冲突域，获得高的带宽。一般来讲每个公司的产品的实现技术均会有差异，但对网络帧的处理方式一般有以下几种：