降雨量

降雨量是指一定时空范围内,专门容器测得的降水量(mm)。降雨的衡量指标有两个,一个是累积雨量,一个是降雨强度。中国气象局规定:24小时内的降雨量称之日降雨量,凡是日降雨量在10毫米以下称为小雨,10.0～24.9毫米为中雨,25.0～49.9毫米为大雨,暴雨为50.0～99.9毫米,大暴雨为     

井灌区地下水开采量与降雨量关系研究

在多年对太原盆地井灌区地下水开采量和降雨量监测的基础上,分析了井灌区54a降雨量的特征,利用典型井计算原理统计了井灌区的地下水开采量,论述了不同水平年地下水开采量的特征,最后通过回归分析法研究了井灌区地下水开采量与降雨量的关系.研究结果表明,年开采量与年降雨量关系显著,年开采量随年降雨量的减小而增大;年开采量与4、9月份降雨量相关性最为显著;通过年开采量、年降雨量与基准年的比值分析表明,开采量比值和降雨量比值呈线性关系.     

"春雨贵如油"?

我国华北地区有句家喻户晓的农谚:“春雨贵如油”。因为华北春雨很少,在自然情况下,主要作物冬小麦的产量几乎和降雨量成正比:“下雨就是下粮食！”这是另一句农谚。     

3种亚高山森林群落林冠截留量及穿透雨量与降雨量的关系

研究了岷江冷杉林、川滇高山栎林及灌竹林等3种典型亚高山森林群落的林冠截留、穿透雨和径流的月动态变化,分析了林冠截留量、穿透雨量与总降雨量的数量关系.结果表明:川滇高山栎林、灌竹林、岷江冷杉林林冠平均截留量分别为278.2,362.1和353.7mm;林冠平均截留率分别占降雨量的35.77%,46.55%和45.47%.岷江冷杉林径流量为5.9mm,仅占降雨量的0.76%.3种群落穿透雨量分别占降雨量的53.77%,53.45%和64.23%.另外,建立了3种群落类型的穿透雨量、林冠截留量与大气降雨量之间的回归模型,用于定量评价该地区亚高山森林的生态水文效应.     

Climatic regionalization mapping of the Murrumbidgee Irrigation Area,Australia

In this study,spatial analysis techniques were used to generate climatic zoning maps of the East Murrumbidgee Irrigation Area (MIA),Australia.Long term climate data were used to analyze and assess regional climatic variation by cluster analysis in a GIS environment.Based on thermal and moisture factors,four variables were chosen to develop climate zones.These variables include annual average rainfalls,annual average ETc,annual average Growing Day Degree (GDD) and daily average temperature generated from daily climate data of 36 years (1971-2006) on 12 local weather stations as the fundamental elements of regional climate characteristics.GIS-based spatial analysis models are used to map climate sub-regions from sets of climatic parameters derived from regional climate data sources.Two climate zoning schemes are presented by integration of spatial interpolation,spatial cluster analysis and climate indices methods.One scheme comes with the two climate zones of the West and the East based on spatial cluster analysis according to selected climatic variables,and the other comes with the three comprehensive hydro-thermal zones and the six hydro-thermal balance zones.     

区域降雨的丰枯特性及其补偿特性分析

利用天津市北三河境内18个雨量站、1960--2005年共46年的年降雨量资料,依次对北运河、潮白河、蓟运河流域的年降雨进行了丰枯判别、连丰、连枯概率和稳定概率计算,并利用Kriging插值模型和集对理论对各流域间的降雨补偿特性进行了分析．结果表明：连续两年出现平水年的概率为最大;北运河流域的丰枯交替比其他流域频繁;北三河系各流域间的降雨量基本是正相关的,即遭遇的机会较多,存在一定的丰枯同步性,即自产水不利于补偿调节,易产生区域性的洪涝灾害和干旱缺水问题．     

陕北黄土区山地苹果园土壤水分动态变化特征研究

以八年生矮化红富士果树为试材,采用野外定位观测法,对陕西省延安地区苹果园0～100 cm不同深度土壤水分与温度及相应气象要素进行连续1年的定位观测分析,对土壤水分的动态变化规律、时空变化及影响因子进行研究。采用方差分析、相关性和主成分分析方法探讨土壤水分的主导因素及其相互关系。研究表明：观测期土壤墒情的季节变化可划分为水分快速消耗期（4—6月）、水分恢复期（7—10月）、稳定期（11—次年3月）;土壤体积含水量由浅到深呈先增后减、稳定性增强、垂直变化季节差异显著等特点;主成分分析结果表明,第一主成分中土壤温度及电导率所占比重较大,第二主成分中大气温度和湿度指标权系数的绝对值在所有主成分指标系数中是最大的,降雨量是第三主成分中标权系数最大的;研究区降雨量季节分配极不均匀,主要集中在生长季7—9月,占全年降雨量的73.5%,不同月份、深度的土壤水分变异系数均属于中等程度变异,土壤水分与大气温度、电导率降雨量、相对湿度、降雨量表现出极显著正相关关系,而与风速呈极显著负相关（P<0.01）。该研究揭示了山地苹果园土壤水分的变化规律,可为黄土高原地区果园的建设和管理提供理论依据。     

临沧地区暴雨气候特征分析

暴雨及其引发的洪涝、泥石流、滑坡等是临沧地区的主要自然灾害，对全区工农业生产和人民生命财产造成的损失十分严重。统计41年来临沧地区8县逐日雨量资料，分析暴雨天气的气候特征，探索暴雨发生的一般规律，对进一步地提高暴雨天气预报准确率，提供防灾减灾的科学依据 有十分重要的意义。     

A physically-based statistical forecast model for the middle-lower reaches of the Yangtze River Valley summer rainfall

A new approach to forecast the middle-lower reaches of the Yangtze River Valley summer rainfall in June-August （JJA） is proposed in this paper. The year-to-year increment of the middle-lower reaches of the Yangtze River Valley is forecasted and hence the summer precipitation could be predicted. In this paper, DY is defined as the difference of a variable between the current year and the preceding year （year-to-year increment）. YR denotes the seasonal mean precipitation rate of the middle-lower reaches of the Yangtze River Valley summer rainfall. After analyzing the atmospheric circulation anomalies in winter and spring that were associated with the DY of YR, six key predictors for the DY of YR have been identified. Then the forecast model for the DY of YR is established by using the multi-linear regression method. The predictors for the DY of YR are Antarctic Oscillation, the meridional wind shear between 850hPa and 200hPa over the Indo-Australian region, and so on. The prediction model shows a high skill for the hindcast during 1997-2006, with the average relative root mean square error is at 18%. The model can even reproduce the upward and downward trends of YR during 1984--1998 and 1998--2006. Considering that the current operational forecast models of the summer precipitation over the China region have the average forecast scores at 60%--70% and that the prediction skill for the middle-lower reaches of Yangtze River Valley summer precipitation remains quite limited up to now, thus this new approach to predict the year-to-year increment of the summer precipitation over the Yangtze River Valley （and hence the summer precipitation itself） has the potential to significantly increase the operational forecast skill of the summer precipitation.     

抗旱造林技术探讨

神木县位于陕西省北部，这里十年九旱，平均年降雨量260—390mm之间，而且多集中在七至九月份，春季干旱少雨，时有大风，沙尘暴侵袭，夏季干热、冬季干冷，属于典型的干旱、半干旱地区，这样的气候环境，要提高造林成活率，必须做好以下这几方面的工作。