Chinese Journal of Agrometeorology

Discussion on Scientificalness Problem of Accumulated Temperature and Its Unit

ZHENG Da-wei1,SUN Zhong-fu2(1.Department of Agrometeorology,China Agricultural University,Beijing 100193,China;2.Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081)

2010, 31(02): 165-169.

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Accumulated temperature is a basic specialized term in agrometeorology and other relative subjects which often occurs in papers of different journals. But there has been a big confusion of its scientificalness and unit for hundred years. Its origin,development,problem of scientificalness and improvement were reviewed in this paper. J.L.Monteith's theory was particularly introduced,in which the essential aspect of thermal time was discovered and explained. Paper titles with term of accumulated temperature and other terms with the same meaning i.e. thermal time,degree-day and heat unit in CAB Literature from 1990 to Oct. 2008 were retrieved. Results showed that there were less and less scientists using accumulated temperature,most using degree-day but more and more using thermal time. Considering the term of accumulated temperature had been using in China for dozens years and was very popular,in order to solve the problem of scientificalness and to keep agreed with physical principles,it was suggested to be replaced by "integrated temperature" ,which had the same Chinese characters and pronunciation,and the unit of "℃" should be also replaced by "℃·d". At the same time,the term explanation of "heat resource" in revised edition of Chinese Agronomic Terms(1993)was renewed as the following:a type of climatic resource different with heat energy in physics,i.e. combination of usable temperature conditions in agriculture and its continued time,usually expressed as integration of temperature to time.

Analysis of Extreme Precipitation and Temperature Events in Hebei Province over Last 50 Years

WANG Xiao-dong1,2,PAN Xue-biao1,2,LONG Bu-ju2,LI Chun-qiang1(1.Key Laboratory of Ecology and Environment Observation of Hebei Province,Shijiazhuang 050021,China; 2.College of Resources and Environmental Science,China Agricultural University,Beijing 100193 )

2010, 31(02): 170-175.

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There were important impacts of extreme climate events on agriculture. Based on the daily mean temperature,daily maximum temperature,daily minimum temperature and daily precipitation data at 17 stations in Hebei Province(include Beijing and Tianjin)from 1957 to 2006,using linear analysis combined with GIS spatial analysis methods,the spatial and temporal characteristics of changes in weather and climate extremes in Hebei Province over last 50 years were studied. The results showed that both the numbers of heavy rain days and the extreme intense precipitation events decreased,and dry spell events increased,however its increasing tendency was not distinct. There were obvious differences in trends of the extreme intense precipitation and the number of heavy rain days between the east and west parts of Hebei Province. The extreme hot days increased,while the extreme cold days decreased,and the tendency of winter warming was remarkable. Low temperature days significantly decreased,but high temperature days increased a little,it had a very good consistency in the spatial distribution of the extreme temperature events. There were warming and drying trends in Hebei,and the adapting agricultural technique should be taken.

Variation of Extreme Precipitation Index(Maximum Consecutive 5-day Precipitation Totals) in the Three Gorges during 1961-2007 and Scenario Projections

ZHANG Tian-yu1,FAN Li1,CHENG Bing-yan1,TANG Hong-yu1,LIU Xiao-ran1,XU Chong-hai2(1.Chongqing Climate Center,Chongqing 401147,China;2. National Climate Center,CMA,Beijing 100081)

2010, 31(02): 176-182.

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Based on the daily precipitation data during 1961-2007 from 17 stations in the Three Gorges area,temporal variation of Maximum consecutive 5-day precipitation totals (referred to as R5d)was analyzed. Through evaluating the simulation ability of 9 IPCC-AR4 Coupled Climate Models,the results of R5d in 2001-2100 relative to the average of 1980-1999 in the Three Gorges,projected by the 5 models under the A2,A1B,and B1 emissions scenarios of SRES were showed. The results showed that the linear trend of R5d was not obvious and existed obvious 2 years and 5 years periods of inter-annual variation in recent 47 years. The decadal change of R5d,1960s and 2001-2007 was relatively small,1970s,1980s and 1990s on the high side relative. Compared to the current climate (1980-1999),R5d in the Three Gorges would be increased in the majority of time in the 21st century under different SRES,especially increased more significantly in the late 21st century than the early and the middle 21st century. Under the A2,A1B,and B1 emissions scenarios,in the early 21st century R5d would be increased by 0.5~5.4mm,in the middle 21st century increased by 9.3~14.8mm,and in the late 21st century increased by 12.7~26.4mm.

Efficiency Evaluation of Precipitation Generated by CLIGEN in North China

LI Ming-cai,GUO Jun(Tianjin Climate Center,Tianjin 300074,China)

2010, 31(02): 183-187.

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To determine the efficiency of precipitation generated by CLIGEN in North China,precipitation records from 15 weather stations from 1951 to 2008 in North China and 150 years of CLIGEN generated data were used to evaluate the CLIGEN weather generator. Results showed that the means of annual and daily precipitation amount and days of precipitation were all well generated by CLIGEN,whereas extremes of precipitation were not adequately preserved. Mean Absolute Relative Errors (MARE)of annual and daily maximum precipitation were both higher compared with that of annual and daily average precipitation. Nonparametric tests indicated CLIGEN had the ability to simulate probability distribution of annual and daily precipitation. In general,CLIGEN could generate statistical characteristics of average annual and daily precipitation,as well as variability of precipitation.

Spatio-temporal Evolvement of Frostless Period in Liaoning Province in Recent 50 Years

CAI Fu1,MING Hui-qing2,JI Rui-peng1,ZHANG Shu-jie1,FENG Rui1,WU Jin-wen1,ZHANG Yu-shu1,WANG Yang3(1.Institute of Atmospheric Environment,CMA,Shenyang 110016,China; 2.Service Center of Meteorological Science and Technology in Liaoning Province,Shenyang 110016; 3. Meteorological Bureau of Fushun City,Fushun 113100)

2010, 31(02): 188-193.

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Based on daily ordinal observation data of the temperature from 52 stations in Liaoning Province over the recent 50 years (1961-2007),the spatio-temporal evolvement characteristics of frostless period in Liaoning Province were investigated by using GIS technique,climatic trend rate and abrupt change analysis methods. Results demonstrated that in terms of regional average,frostless period initial date ordinal (FLPIDO)moved up 2.2 days per 10 years,with a climate abrupt change happened around 1989,and frostless period ending date ordinal (FLPEDO)and duration (FLPD)postponed and increased significantly by 1.9 days and 3.9 days per 10 years,respectively. Abrupt change for FLPEDO happened around 1975. FLPD increased significantly with rate of 3 to 4 days per 10 years in most past of Liaoning. Second,there were significant difference for different periods' average (period A:1961-1990;period B:1971-2000). The FLPIDO in period B was earlier and FLPEDO was later and FLPD was longer than that of in period A. Third,the large and small values of area of FLPD were larger in 1970s than that of in 1960s in the GIS map,and the large value area enlarged continue but the small value area shrank in 1980s,and there was no significant difference between 1980s and 1990s,and the large value areas covered most of Liaoning and small value areas shrank remarkably after 2000.

Research on Climate Change in Zunyi City in Recent 48 Years

YAO Zheng-lan,YAO Yi (Zunyi Meteorological Administration of Guizhou Province,Zunyi 563002,China )

2010, 31(02): 194-199.

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Climate change is a objective reality,but varies in different regions. By using climate variability,trend coefficient and accumulative anomaly method,temperature,precipitation and sunshine-based characteristics and tendency of climate change in Zunyi City dating from 1961 to 2008 were measured. The results showed that the temperature had an increasing tendency in the recent 48 years with seasonal and regional diversity,mainly in February and November (P<0.05). But in July and August,the temperature had an obvious decreasing tendency (P<0.05),and in other months,there was no obvious change (P>0.05). The temperature in urban areas,Meitan and Wuchuan had an increasing tendency,but that in Chishui and Yuqing had a decreasing tendency. Increasing temperature in winter and decreasing temperature in summer resulted in a year-by-year drop trend of the annual mean temperature in the whole region. There was no obvious precipitation change tendency (P>0.05),but there was a marked decrease tendency of sunshine duration (P<0.05)in the whole region,especially in summer. The changing environment around the meteorological observing station and human activities also influenced the change of temperature and sunshine duration.

Advances in Research of Impacts of Climate Change on Agriculture

ZHAO Jun-fang1,GUO Jian-ping1,ZHANG Yan-hong2,XU Jing-wen3(1. Chinese Academy of Meteorological Sciences,Beijing 100081,China; 2. National Meteorological Center,Beijing 100081; 3. College of Resource and Environment,Sichuan Agricultural University,Yaan 625014)

2010, 31(02): 200-205.

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In this paper we summarized a series of scientific achievements about the impacts of climate change on agriculture in recent decades,mainly about the impacts of climate change on crop growth,yield,quality,planting distribution,agriculture cost,and so on. Finally,based on the current researches,we pointed out the insufficiency which existed at present studies and some areas to be improved,and then put forward prospects in the future.

Characters of Evapotranspiration and Water Supply-demand Relation for Chinese Ephedra in Mu Us Sandy Land

WANG He-song1,SANG Yu-qiang2,DAI Xi-hong3,ZHANG Jin-song1,MENG Ping1,GAO Jun1(1.Research Institute of Forestry,CAF/Key Laboratory of Forest Silviculture of the State Forestry Administration,Bejing 100091,China; 2. Forestry and Horticulture College,Henan Agricultural University,Zhengzhou 450002; 3.Yulin Meteorological Bureau,Yulin 719000)

2010, 31(02): 206-210.

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Monitoring and calculating the evapotranspiration and the relationship between supply and demand of water for Chinese Ephedra,an important medicinal plant in Mu Us Sandy Land,were conductive to better understanding of characters of water consumption and water physio-ecology. Evapotranspiration (ET) of Chinese Ephedra and its canopy micrometeorological factors in Mu Us Sandy Land was calculated and measured by eddy covariance technique and meteorology automatic monitoring system respectively in the growing season of 2004. ET and the relationship between supply and demand of water for Chinese Ephedra were analyzed. Main results were showed as follows:(1) in growing season,ET exhibited a large temporal variation. Its diurnal variation showed a single peak change in clear/cloudy days,a multi-peak change in overcast days. Regarding the daily variation,it increased in the beginning of the growing season,getting to peak in June and July,and decreased gradually in August,reaching the bottom in September. The average value and total amount of ET was 0.60mm/d and 93.6mm respectively. (2) There was a well multiple correlation (P<0.01,R2=0.731) between ET and the micrometeorology factors:global radiation (Ra),air temperature (Ta),relative humidity (RH) and wind speed (V). Ra was the most important micrometeorology factor that effected ET by the partial correlation coefficient. (3) The ratio of (R/TR) was 2.9. In terms of annual value,there was no water supply and demand conflict,or water shortage and water stress in the experiment area. However,in the beginning of the growing season,precipitation was not sufficient for water consumption,imposing constraint to the growing of Chinese Ephedra in its earlier growing season.

Measurement and Calculation of Photosynthetically Active Radiation at Luancheng Region

BAI Jian-hui(Key Laboratory of Middle Atmosphere and Globe Environment Observation,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)

2010, 31(02): 211-218.

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Integrated measurement on the solar radiation (including photosynthetically active radiation (QPAR),visible radiation (QVIS),global radiation (Q),and etc.),meteorological parameters at Luancheng were made four times during July 19,2005 to September 31,2006. The variation characteristics of QPAR and QVIS were obtained. The results showed that the ratios of hourly sum of QPAR to Q,QVIS to Q,QPAR to QVIS were relatively stable,averaging at 1.94 mol MJ-1,0.39,4.95 mol MJ-1,respectively. These ratios displayed obvious diurnal,daily and seasonal variations,and were influenced by water vapor,aerosol,clouds and etc. The empirical formulas were built up for calculating hourly sums of QPAR and QVIS and their relationship under actual sky conditions. The calculated QPAR and QVIS were in accordance with the observed data,and their relative biases were 14.4% and 13.9%,respectively,when water vapor and scattering factor were considered. In the actual condition with only water vapor factor considered,their relative biases were 15.2% and 14.2%,respectively. Water vapor played a very important role for the estimation of hourly sums of QPAR and QVIS by using the ratio of QPAR/Q,QVIS/Q. Aerosol's role is less important,but it should also be considered.

Sensitivity Analysis on the Soil Water Parameters in Maize Growth Model in Northeast China

WANG Dong-ni1,MA Yu-ping2,WANG Shi-li2,GUO Chun-ming1(1.Jilin Institute of Meteorological Sciences,Changchun 130062,China;2.Chinese Academy of Meteorological Sciences,Beijing 100081)

2010, 31(02): 219-224.

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In order to improve and optimize the drought evaluation ability of the maize growth simulation model in Northeast China,and to scale up its use on larger region,the sensitivity analysis of parameters in soil water sub-module was carried out.Based on the case study in Yushu (subhumid) and Baicheng (semiarid) weather stations of Jilin province in typical dry years ( 2000,2001) and years with enough or normal precipitation (1998,2002),it showed that:soil moisture was the most sensitive to wilting point,field capacity and crop coefficient and available soil moisture in root zone came second to that.The effects of wilting point,field capacity and initial amount of available soil moisture in root zone on soil moisture were positive.In addition,the results were consistent with different climatic regions and precipitation year patterns. It was difficult to apply the crop growth simulation model on regional scale due to limited measured values of soil and crop parameters mentioned above. And inaccurate estimation of parameters in soil water sub-module could lead to error in soil water content,and further to crop simulation.Simulation precision should be further improved by optimizing parameters according to the results of sensitivity analysis.

Heat Flux Analysis of Inner Surface of North Wall in Solar Greenhouse

WANG Qian,CHEN Jing-ling,SUN Zhi-qiang,ZHAO Yong,WU Ming-zuo,YANG Xi-tian,MIAO Lei(Henan Agricultural University,Zhengzhou 450002,China)

2010, 31(02): 225-229.

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To find out the heat flux of the north wall of the greenhouse,and identify proper thickness of the wall,the temperatures of different depth at top,middle and bottom of the wall,and the air temperatures near inner/outer surface of the wall,were measured. It was showed there were constant temperature layers at the depth of 40-50cm.The heat fluxes at the depth of 40cm were mere 4W·m-2. The calculation result showed that the natural convection of the air near inner surface of the wall was on turbulent flow state,and the convection heat index was 1.69~4.43W·m-2·K-1. The maximum convection heat flux of the inner surface of the wall was 26.5W·m-2 in clear daytime and the wall absorbed radiation 83.6W·m-2 maximally. The conduction heat flux reduced and the phase of the heat flux lagged along with the increase of the depth. The heat flux decreased sharply from clear day to cloudy day. The conclusion was that 60cm was a reasonable thickness of the north wall of the solar greenhouse in zhengzhou,Henan province.

Seasonal Dynamics Model of Aboveground Biomass and Leaf Area Index on Alpine Kobresia humilis Meadow in Qinghai-Tibet Plateau

SUN Jian-wen1,2,LI Ying-nian1,3 ,SONG Cheng-gang1,2,WANG Jian-lei1,2,ZHANG Fa-wei1,3,WANG Qin-xue4(1.Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,China;2.Graduate University of Chinese Academy of Sciences,Beijing 100049;3. Key Laboratory of Adaptation and Evolution of Plateau Biota,Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001;4.National Institute for Environmental Studies,Tsukuba,Ibaraki 3050053,Japan)

2010, 31(02): 230-234.

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Based on the alpine Kobresia humilis meadow vegetation and weather data obtained at Haibei Alpine Meadow Ecosystem Research Station,CAS in 2007,we discussed the seasonal dynamic changes of the Leaf Area Index (LAI) and Aboveground Biomass (AB),analyzed and simulated the correlation between LAI and AB,as well as the influence of climate on the process of LAI and AB. The results showed that during the plant growing season,the seasonal dynamic variation of AB could be fitted by the Logistic Regression model,and the seasonal dynamic variation of LAI could be fitted perfectly by cubic function LAI showed significant correlation with temperature and precipitation and they could be modeled by a binary quadratic function. The relationship of LAI and AB could be stated with a quadratic function.

Effects of No-tillage on the Photosynthesis and Transpiration of Maize in the Semi-arid Area of Northern Shanxi Province

SUN Dong-bao1,SUN Gao-dong2,WANG Qing-suo1 (1.Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences/Key Laboratory of Dryland Agriculture,Ministry of Agriculture,Beijing 100081,China; 2.Animal Husbandry Bureau of Hunyuan County,Shanxi Province,Hunyuan 037400)

2010, 31(02): 235-239.

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The experiment was carried out in the field with three treatments i.e. conventional till (CT),non-till with retaining maize stubble (NT) and mulch-till with un-chopped maize straw mulch (MT).The soil temperature,soil water content,transpiration and photosynthesis of maize in CT,NT and MT were observed. The soil temperature of maize field in no-tillage practices including MT and NT decreased comparing to that in CT. The decrease of the soil temperature was high in MT,and low in NT. The differences of the soil temperature among MT,NT and CT gradually became smaller with the growth of maize. MT and NT could improve the soil water content,especially in 0-60cm depth,comparing to CT. At the seedling stage,the photosynthesis and transpiration rates of maize in MT significantly reduced by 8.5% and 9.7%,respectively,but insignificantly reduced in MT,comparing to CT. At the early jointing stage,the photosynthesis and transpiration rates of maize showed no significant difference among MT,NT and CT. The photosynthesis and transpiration rates of maize in MT were significantly increased at the later jointing stage,the heading stage and the filling stage,respectively while those in NT significantly enhanced only at the filling stage,comparing to CT.

Dynamic Effects on Sugar Metabolism of Soybean Seeds under Acid Rain Stress

ZHANG Fan,ZHOU Qing(Key Laboratory of Industrial Biotechnology,Ministry of Education,Jiangnan University/Environment and Civil Engineering,Jiangnan University,Wuxi 214122,China)

2010, 31(02): 240-243.

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In order to explore the dynamic effects on sugar metabolism of soybean seeds under acid rain stress,in this experiment soybean seeds were leached by distilled water and then treated with simulated acid rain(pH2.5 and pH4.5). The effect of acid rain stress strength on the contents of soluble sugar,reducing sugar,sucrose,starch and α,β-amylase activity of soybean seeds were studied in this paper. The results showed that the content of soluble sugar of AR group rose sharply on the first day and declined significantly on the second day and decreased slowly from then on. The content of reducing sugar of AR group was high in the first 4 days,but declined from the 3rd to 5th day. The content of sucrose of pH2.5 group decreased from the 2nd to 5th day. The content of starch of AR group declined from the 2nd to 4th day. The α-amylase activity of pH4.5 group was higher than CK,but that target of pH2.5 group was lower than CK after the 4th day. The β-amylase activity was higher or equal to CK from the 1st to 6th day,pH2.5 group was lower than CK on the 7th day. All targets of sugar metabolism and amylase activity indicated that the contents of soluble sugar,reducing sugar and sucrose increased with increasing acid rain stress strength,however,the starch was contrary. The effect of acid rain on amylase activity was one of the reasons of germination change.

Effect of Straw Mulch Amount on Dynamic Changes of Soil Moisture and Temperature in Farmland

WANG Zhao-wei1,HAO Wei-ping2,GONG Dao-zhi2,MEI Xu-rong2,WANG Chun-tang1(1.College of Water Conservancy and Civil Engineering,Shandong Agriculture University,Taian 271018,China;2.Institute of Environment and Sustainable Development in Agriculture/Key Laboratory of Dryland Agriculture,MOA,Beijing 100081)

2010, 31(02): 244-250.

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The effects of straw mulch amount on soil water and temperature were studied in dryland agriculture areas in Shouyang of Shanxi province. The dynamic changes of soil moisture,and temperature conditions beneath mulches of maize straw applied at different amount(1500,3000,4500,6000kg/ha ) and soil transpiration were investigated from April to November in 2009,the whole growth season of spring maize. The results showed that straw mulch had a beneficial effect on soil transpiration and temperature of topsoil lay within 40cm at the early growth stage,while had no significant effect at the later stage after reaching the maximum LAI,the beneficial effect of straw mulch on reducing evaporation and improving soil water retention were increased significantly with the increasing applied amount of straw mulch. On the other hand,we found that there were adverse effects of high application mulch amount on soil moisture by interception loss and suspending infiltration of rainfall,and interception and field infiltration of rainfall under mulch condition were related to climate conditions,rainfall intensity,soil hydraulic characteristic etc.,how the straw mulch amount affect field infiltration and interception of rainfall should be further studied. Similarly,Straw mulch affected topsoil temperature,mulch exceed certain amount could lead to low temperature to affect crop growth and yield. In this study,the recommended amount of straw mulch for the studied areas was 4500kg/ha with taking into consideration of integrated effect on both soil water content and temperature. These findings are important for identifying the best straw mulch practices for dryland agriculture,and would provide useful reference for further studies in this field.

Distribution Characteristics of PAR in Rice Canopy and Relationship between PAR and LAI

ZHANG Tao,YIN Hong,XIN Ming-yue(Shenyang Agricultural University,Shenyan 110161,China)

2010, 31(02): 251-254.

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In this research,the PAR (photosynthetically Active Radiation) of rice canopies (incident PAR,reflective PAR of the canopy,the transmitted PAR and the reflective PAR of water surface) of different colonies was observed. On the basis of the observation results,the reflectance of canopy,the reflectance of water surface,the absorbed photosynthetically active radiation (APAR) and the fraction of photosynthetically active Radiation (FAPAR) were calculated and the variation regularities of them were studied. The results showed that,the FAPAR of rice canopy and LAI had extremely strong correlations,with an accuracy of the correlation equation up to 88.48%. This result could be applied to linking the ground data and remote data in large-scale global change research.

Micro-climate Characteristics of Cotton Field under Different Plant Density

LOU Shan-wei1,2,RAO Cui-ting3,ZHAO Qiang1,WANG Hong-wei3 ,GUO Ren-song1 ,GAO Yun-guang1,ZHANG Ju-song1 (1.Xinjiang Agricultural University,Urumqi 830052,China;2.The National Engineering Research Center of Cotton,Urumqi 830091;3. Aksu Agricultural Technology Promotion Center,Aksu 843000)

2010, 31(02): 255-260.

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In order to study the effect of density on micro-climate in the cotton field,temperature,air humidity,soil moisture of different canopy structure with different density (9.0×104,13.5×104,18×104,22.5×104,27.0×104 plant/ha) were assessed through field trial in Akesu region in 2008. The results showed that the height of cotton plant was between 55-75cm with the designed density,and the height,stem diameter,boll-bearing branch decreased with the rise of density. During the flowering and cotton-blowing period,the cotton canopy air temperature was higher over in the other periods(the highest was more than 31℃). The diurnal temperature increased first and reduced later. The temperature in the narrow row was higher than the wider line,and the temperature was higher in height of 40cm than in the height of 20cm in the canopy. Relative humidity was in line with the upward opening parabola model,high in the flowering stage with small change and lowest at noon,which was only 40% or so and 10% higher than in the cotton wool period. The relative humidity under middle density was steady. In terms of the soil moisture,surface evaporation was serious under small density,and the transpiration from leaf was heavy with oversized density. Therefore,with moderate density treatment,soil moisture could be maintained at a good and steady condition. The soil temperature under dense canopy treatment was higher at the depth of 15cm in the early stage and then getting low due to the shadow of leaves and rising again in the later stage. However,the difference (less than 1℃) was not obvious among these treatments.

Analysis on the Temporal-spatial Variations of Differences between Evapotranspiration and Precipitation(DEP) During the Growth Period of Winter Wheat in Hebei Province

KANG Xi-yan,LI Chun-qiang,GAO Jian-hua,WANG Xin(Hebei Key Laboratory for Meteorology and Eco-Environment/Meteorological Sciences Institute of Hebei Province,Shijiazhuang 050021,China)

2010, 31(02): 261-266.

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Evapotranspiration and precipitation are two main parameters during the growth period of winter wheat and also important for irrigation planning. Based on the climate data of 48 weather stations throughout the winter wheat areas of Hebei Province from 1965 to 2007 and Penman-Monteith equation recommended by FAO,the Differences between Evapotranspiration and Precipitation (DEP) during the growth period of winter wheat and its temporal-spatial variations and the relationships with meteorological factors were analyzed. The results showed that the DEP were positive during whole winter wheat growth period,which meaning the water deficit of winter wheat growing. The times of the most water deficit was in the middle period of winter wheat growing and had little variation,and the largest region of water deficit was located in the southeastern part of Hebei Province. Water deficit in the medium-term of growth period was most serious and less variable. Under the climate change,the DEP had a declining tendency during the whole growth period,and it declines significantly at 0.01 level of statistical test in the late term,but not significant in other times of growth period,and the changing rate of DEP was little in the whole growing seasons for winter wheat during 1965 to 2007. The main reasons that caused the DEP decline was the reduction of sunshine duration and wind speed in the whole growth period,although minimum temperature had a limited impact. At the same time,the advancement of agrotechniques such as crop variety and management practices also played a role for the variation of DEP.

Effect of Climatic Conditions on Summer Soybean Growth in Huaibei Region

QI Shang-en,SUN You-feng,QI Huan,LI De,LU Qin-qin(Suzhou Meterological Bureau,Suzhou 234000,China)

2010, 31(02): 267-270.

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Based on 14 years data of growth and development of summer soybean and agro-meteorological observation from Suzhou station,the impact of reproductive stages and the key meteorological factors on summer soybean growth was analyzed using SAS software. The results showed that summer soybean flowering to filling was the most sensitive stage to changes of meteorological factors,and the fitting model was at the very significant level,and that the average diurnal temperature range,rainfall and rainfall days were main factors in the stage. Other stages were not sensitive to climatic factors.

Calculation and Comparison of Vegetation Net Primary Productivity(NPP) in Zhejiang Province with Three Models

SUN Shan-lei1,2,ZHOU Suo-quan1,2,SHI Jian-hong3,LIN Yi4,XUE Gen-yuan5,LAI An-wei6,LI Hong-li1,2(1.Jiangsu Key Laboratory of Meteorological Disaster,Nanjing 210044,China; 2.Nanjing University of Information Science & Technology,College of Atmospheric Sciences,Nanjing 210044;3. Wenzhou City Meteorological Bureau in Zhejiang Province,Wenzhou 325000; 4. Liaoning Province Meteorological TV Center,Shenyang 110015; 5. Ningbo Meteorological Bureau,Ningbo315012; 6.Institute of Heavy Rain,CMA,Wuhan 450001)

2010, 31(02): 271-276.

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Using Miami model,Thornthwaite model and Comprehensive model,NPP in Zhejiang Province was calculated to find an optimal model through comparing the calculating results with the values by IBP recommended. Then,the characters of annual and decadal NPP were analyzed. Based on the multiplex regression equation,the NPP was carried out spatial interpolation with longitude,latitude,DEM and its derived data. And spatial distribution of NPP was investigated. The results showed that (1) the calculation of comprehensive model was between 952.722 and 1376.971g m-2 per year,which was most close to the recommended values,and NPP wavelike ascended with time. (2) For the three NPP models,the maximum appeared in Jiaxing of the north and the minimum value appeared in Wenzhou of the south. NPP's spatial distribution of the three models all showed that the lower value appeared in northwest and the higher appeared in southeast. (3)Comprehensive model were more feasible to calculate NPP of Zhejiang Province.

Research Progress on Agricultural Climatic Division Methods in China

WANG Lian-xi1,CHEN Huai-liang2,LI Qi1,YU Wei-dong2(1. Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of Information Science and Technology,Nanjing 210044,China; 2. Henan Institute of Meteorological Sciences/Key Laboratory of Agrometeorological Safeguard and Applied Technique,CMA,Zhengzhou 450003)

2010, 31(02): 277-281.

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Agricultural climatic division is one of the effective approaches for the reasonable use of the agricultural climatic resource,so it is widely focused and utilized. In this paper,the research progress on agricultural climatic division methods in China was discovered from the index selection methods of agricultural climatic division,agricultural climatic division methods and the application of geographic information system on the agricultural climatic division,and the advantages and disadvantages for the different division methods were discussed. Furthermore,potential directions were pointed out in this research field to provide some reference for researchers.

Research Progress of Pollen Variable Models for Forecasting Crop Yield

SHAN Kun,LIU Bu-chun,LI Mao-song,WU Yong-feng( Institute of Environment and Sustainable Development of Agriculture,Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment & Climate Change/Key Laboratory of Dryland Agriculture,Ministry of Agriculture,Beijing 100081,China)

2010, 31(02): 282-287.

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In order to explore the potential of models introduced with pollen variable for forecasting harvest yields,progress in the forecast model research was summarized. It was indicated that the accuracy of the forecasting results could be enhanced by introducing pollen variable in traditional statistical models which were composed only of meteorological variables. Due to the limitation in the monitoring technologies,the forecast model was more applicable to the single crop in the same growing period. In the area where various crops were separated in small size fields in the same growing period,the forecasting accuracy of this kind of model was largely depended on the quality and quantity of the pollen data obtained by using the relevant monitoring technologies. In order to improve the application potential of pollen variable models in China.It is necessary to build the complete monitoring network,improve and develop the pollen recognition technology,and also accumulate enough pollen variable data for a stable and comprehensive yield forecast model.

Spatio-temporal Changes of NDVI and Their Relationships with Runoff in the Poyang Lake Basin

SHAO Bu-fen,ZHOU Suo-quan,GU Ting-ting,LI Qiang(Nanjing University of Information Science &Technology/Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing 210044,China)

2010, 31(02): 288-294.

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Based on the 8km resolution multi-temporal NOAA AVHRR-NDVI datasets and the daily runoff data from four hydrometrical stations during 1982-1999,the characteristics of NDVI and runoff and their relationships in four sub-regions of Poyang Lake Basin were studied at annual and inter-annual scales by using the methods of inter-decadal variations,correlation analysis and Morlet wavelet analysis. The results indicated that the mean annual NDVI increased all in four sub-regions from 1982 to 1999 and the inter-annual NDVI varied with the same trend. NDVI was mainly influenced by precipitation and runoff. The correlation coefficient between NDVI and runoff were positive and significant statistically in the whole region,and NDVI maximally respond to the variation of runoff with a lag of about 3 months. The runoff generally oscillated with a cycle of about 12 months in all sub-regions,and in several sub-regions,it oscillated with the cycle of about 35 and 62 months. The frequency distribution of each oscillation signal was different,not only in time domain but also in intensity,of which the cycle of 12 months was the strongest of all and the short cycle was stronger than the long cycle. The NDVI had the same characteristics of cycle oscillation as that of runoff.

GIS-based Analysis on the Relationship between Land Use/cover and Land Surface Temperature in Zhejiang Province

ZHANG Xiao-wei,HE Yue,CAI Ju-zhen,LI Zheng-quan(Zhejiang Climate Center,Hangzhou 310017,China)

2010, 31(02): 295-299.

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Land surface temperature (LST) was retrieved from MODIS data by using split-window algorithm of Zhejiang Province in 2008. With the support of remote sensing and geographical information system (GIS),the temporal and spatial character of LST was analyzed. The relationship between LST and land use/cover types was quantitatively investigated as well as the relationship between LST and normalized difference vegetation index (NDVI). The results showed that ①spatial heterogeneity of LST was determined by the altitude and land use/cover types; ②there were distinct differences among different land use/cover types while the trend of the month change was similar. The annual average LST of different land use/cover types present:LSTbuilt>LSTcrop> LSTforest>LSTwater; ③The results of regressive analysis showed an inverse correlation relationship between LST and NDVI within all land use/cover types except water. The study on the distribution and seasonal fluctuation of LST was of important value in providing new way of dynamic monitor the disaster,such as high temperature shock and low temperature frozen. It was also important for the disaster prevention and reduction as well as for the land planning of the local government.

Research on the Characteristics of the Air Temperature of Lower Landlocked Mountain Slopes in Winter

CHEN Hui1,XU Zong-huan1,PAN Wei-hua1,WANG Jia-yi1,LIN Liang-fa2,DENG Yi-min3,CAI Wen-hua1 (1.Institute of Meteorological Science in Fujian,Fuzhou 350001,China;2.Zhangzhou Meteorological Office,Zhangzhou 363000;3.Longhai Meteorological Office,Longhai 363100)

2010, 31(02): 300-304.

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According to the air temperature data over the last 50 years in Longhai weather station,the freezing damage for Litchi trees could be avoided. But in the year of 1991/1992 and 1999/2000,the Litchi trees were suffered serious freezing damage in Shuangdi Overseas Chinese Farm,11 km away to south-southwest of Longhai Station. To make clear of cause for freezing damage,the air temperature data in winter of 2008/2009 in Longhai weather station and auto weather station of Shuangdi Overseas Chinese Farm (lied in lower parts of landlocked mountain slopes) were comparatively analyzed. The results showed that the average temperature and the minimum temperature of weather station of Shuangdi Overseas Chinese Farm were lower than those of Longhai weather station. However,the maximum temperature observed by the latter station was higher and the daytime temperature differences between the two weather stations were wider accordingly. Moreover,there was linear relation of minimum daytime temperature of two weather stations (r=0.9468>r0.001,n=90),and with the decreasing of the minimum temperature of Longhai weather station,the difference value of the minimum temperature between the two weather stations presented increasing trend,and the minimum temperature of Shuangdi Overseas Chinese Farm was even lower than that of Longhai county. Furthermore,the annual extreme minimum air temperature data from the new and old weather stations in Longhai were adjusted homogeneously by difference method. By using the linear regression analysis,the minimum temperature of weather station of Shuangdi Overseas Chinese Farm in 1991/1992 and in 1999/2000 were -5.8℃ and -4.8℃ respectively,which was the real reason for the freezing damage to Litchi trees.

Study on the Anti-freezing Effects of Mulching in the Tea Plantation

YANG Shu-yun1,JIANG Chang-jun1,SUN Ya-dong2(1.Anhui Agricultural University,Hefei 230036,China;2.Hefei Meteorological Bureau,Hefei 230061)

2010, 31(02): 305-309.

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The role of surface coverage in tea plantation was studied in the paper. The experiment was conducted in January 2009,the coldest month in Hefei with four kinds of experiments dealing:thick straw mulching,thin straw mulching,plastic film mulching and CK. The analysis showed that there was anti-correlation between the daily minimum temperature of each experiments and solar radiation,and the anti-correlation between the mulching surface,s minimum temperature and solar radiation was stronger than that between the surface,s minimum temperature and solar radiation. The average minimum temperature was:thick straw mulching,1.2℃,thin straw mulching,1.1℃ and plastic film mulching -1.4℃,4.4℃,4.3℃ and 1.8℃ higher than CK,respectively. It indicated that the heat-preservation role of the straw mulching was stronger than plastic film mulching,and the thickness of straw mulching caused little difference. The maximum temperature of ground surface under straw mulching was lower than the plastic film mulching,mainly due to the plastic film,s permeability to the solar radiation. The difference of canopy,s leave frostbite was not obvious among each treatment. The earliest germination of spring tea was the plastic film mulching,followed by the CK and the last was the straw mulching. It could be concluded that the plastic film,s permeability was superior and the warming capacity was better than straw mulching and bare ground.

A Review on Response of Plant to Low Temperature and its Cold Resistance

CAO Hui-ming1,SHI Zuo-min1,ZHOU Xiao-bo2,LEI Peng-zhi2,DONG sheng-gang2(1. Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry /Key Lab on Forest Ecology and Environmental Sciences,State Forestry Administration,Beijing 100091,China;2. Forestry Bureau of Lixian County,Lixian 623100)

2010, 31(02): 310-314.

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Low temperature is a key limiting factor for growth,development and distribution of plant species. From eco-physiological point of view,the responses of plant morphological characteristics,biochemical matters,and photosynthetic process to low temperature were reviewed. The relationships between the adaptation capacity of plant to low temperature,cold resistance,and environmental factors including light,water and temperature were also reviewed respectively. Key points for the future research on plant cold resistance were suggested at the end of this paper.

Research on the Drought Disasters in Tangshan Region over the Recent 800 Years

GONG Yu1,2,HUA Jia-jia1,WANG Ai-jun1(1.Tangshan Meteorological Bureau,Tangshan 063000,China; 2.Laboratory of Meteorological and Ecology Environment,Hebei Province,Shijiazhuang 050021)

2010, 31(02): 315-319.

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In order to study the regularity of drought damage at Tangshan region,the data of drought from A.D. 1164 to 2000 in this area was collected and analyzed in the paper. The results showed that drought struck this area 127 times in total and occurred every 6.6 years. The low-grade,middling-grade,serious-grade and the worst-grade of drought damage according to the percentage of happening times,were 45.7%,25.2%,17.3%,11.8%,respectively. The frequency of drought was marked into four levels:very little,little,much and very much in according to time interval( 46 years,5 years,10 years and 2.5 years respectively). The frequency of the drought after A.D. 1800 was 3.6 times than it was before. The emergence of drought was in line with the climate abnormal change and rainfall distribution character.

Analysis on the Red Spider-prone Weather Conditions in Shiyang River Basin

MA Xing-xiang1,2,LI Wan-xi2,LAN Xiao-bo3,LIU Hui-lan2(1. Lanzhou Institute of Arid Meteorology,China Meteorological Administration/ Key Laboratory of Arid Climate Change and Reducing Disaster of Gansu Province/ Key Laboratory of Arid Climate Change and Reducing Disaster,China Meteorological Administration,Lanzhou 730020,China; 2. Wuwei Agro-meterorogical Experiment Station,Wuwei 733000;3. Meteorological Bureau of Wuwei City,Wuwei 733000)

2010, 31(02): 320-323.

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In order to grasp the change regularity of meteorological conditions under which the corn spider mite is prone to happen and dissipate,and to effectively mitigate the red spider corn hazards,the influence of meteorological condition on red spider-hit time,degree and key time to yield were analyzed based on the observation data of red spider and meteorological data from 1991 to 2007. Statistical analysis showed that there was relationship between the spider's harming fastigium and mean temperature in autumn. Mean temperature had increased rate 0.2 ℃ per year in Autumn,surpassing the date of suitable growing temperature for red spiders and,the peak of spider mite's attack against maize were tending be later. The number of overwinter spider mites,first appearing period,harming fastigium,injury ration of plant and loss of yield were investigated and relationship between these factors and meteorological factors such as mean temperature of ten-days,month air temperature,the ground temperature,relative humidity,transpiration,precipitation,sunshine duration were assessed. The model for forecasting the red spider' action had been set up,which could be applied into practical production.

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