Cloud microphysical and rainfall responses to zonal perturbations of sea surface temperature: A cloud-resolving modeling study

The cloud microphysical and rainfall responses to zonal perturbations of sea surface temperature (SST) are investigated by analyzing the equilibrium simulation data (from day 31–40) obtained from a series of two-dimensional cloud-resolving simulations with a zonal model domain of 768 km. Four experiments imposed by zonal SST perturbations of wavenumbers 1 (SST29Z1), 2 (SST29Z2), 4 (SST29Z4), and 8 (SST29Z8) are compared to the control experiment imposed by zonally uniform SST (SST29). The model domain mean SST is 29 C, and the two-dimensional cloud-resolving model with a cyclic lateral boundary is also imposed by zero vertical velocity and constant zonal wind. The time and model domain mean surface rain rates in SST29Z1, SST29Z2, and SST29Z8 are about 10% larger than those in SST29, whereas the mean surface rain rates in SST29Z4 and SST29 are similar. The analysis of mean surface rainfall budgets shows that local water vapor and hydrometeor changes play important roles in determining the differences and similarities in mean surface rain rate between the perturbation experiments and the control experiment. Both convective and stratiform rain rates are larger in SST29Z1 and SST29Z2 than in SST29 due to the smaller advection of rain from convective regions into raining stratiform regions and the larger vapor condensation rates associated with the larger water vapor convergence over raining stratiform regions in SST29Z1 and SST29Z2. The convective rain rates are larger in SST29Z4 and SST29Z8 than in SST29 because of the larger condensation rates associated with the larger water vapor convergence over convective regions in SST29Z4 and SST29Z8. The stratiform rain rates in SST29Z4 and SST29Z8 are smaller than in SST29 due to the smaller vapor condensation rates and smaller collection rates of cloud water by rain over raining stratiform regions in SST29Z4 and SST29Z8.     

洱海净入水量与降雨量关系分析

对洱海各方面资料进行了认真收集整理，通过计算得到净入水量资料，并对净入水量的分布特点进行了分析，再对洱海净入水量与降雨量关系进行了定性讨论．之后又用分段相关法对洱海净入水量与降雨量关系进行了定量分析，得出净入水量与降雨量之间具有较好而稳定的相关关系，并建立了用降雨量估计净入水量的定量关系。     

基于GIS的华北地区降雨量空间变异性

根据华北地区1971年至2000年48个气象站降水空间观测数据,其降水稀疏且分布 不均匀,应用地理信息系统IDRISI软件对降雨量进行空间变异性分析,首先将数据进行处理,生成矢量数据文件,使用IDRISI软件中空间依赖性建模器对矢量数据文件进行分析,生成半方差表面图和方向方差图,进而分析华北地区降雨量空间变异性,总结降雨分布规律.即在127度方向上降雨量变异性最大,在同一条37度斜线附近气象站的降雨量变异性最小.     

长汀县2010年6月21日暴雨局部大暴雨天气分析

0引言 受低层低涡切变东移南压影响,2010年6月21日全县出现了大范围的暴雨天气（表1）,全县18个乡镇有13个乡镇的降雨量大于50毫米,最大降雨量在铁长乡108毫米,超过80毫米的站点有馆前、庵杰、铁长、古城、大同、新桥、南岩、河田、举河、三洲。此次暴雨过程造成全县直接经济损失300万元。本文利用常规气象资料、区域自动站资料及新一代天气雷达回波图、卫星云图等资料对此次全县性暴雨天气做了分析。     

“不要绿化沙漠”——连续多年干旱，促使以色列重新审视水资源利用

今年是以色列发生持续干旱的第四个年头.去年冬季,以色列的降雨量仅为过去年平均降雨量的65%.在以色列境内,大约30%的淡水来自太巴列湖,但目前该湖的水位正在接近警戒线.     

Comparison of semivariogram models for kriging monthly rainfall in eastern China

An exploratory spatial data analysis method(ESDA) was designed Apr.28,2002 for kriging monthly rainfall.Samples were monthly rainfall observed at 61 weather stations in eastern China over the period 1961-1998.Comparison of five semivariogram models(Spherical,Exponential,Linear,Gaussian and Rational Quadratic)indicated that kriging fulfills the objective of finding better ways to estimate interpolation weights and can provide error information for monthly rainfall interpolation.ESDA yielded the three most common forms of experimental semivariogram for monthly rainfall in the erea.All five models were appropriate for monthly rainflaa interpolation but under different circumstances.Spherical,Exponential and Linear models perform as smoothing interpolator of the data,whereas Gaussian and Rational Quadratic models serve as an exact interpolator.Spherical,Exponential and Linear models tend to underestimate the values,On the contrayr,Gaussian and Rational Quadratic models tend to overestimate the values.On the contrary,Gaussian and Rational Quadratic models tend to overestimate the values,Since the suitable model for a specific month usually is not unique and each model does not show any bias toward one or more specific months,an ESDA is recommended for a better interpolation result.     

方形土楼夯土墙的风驱雨量分布

对方形土楼进行风洞试验和数值模拟,在数值模拟风场和试验风场达到较好一致性时引入降雨过程的计算模型.采用该方法研究方形土楼在不同风速、不同降雨量,以及不同屋檐悬挑长度下迎风墙面风驱雨量的分布特征.研究结果表明:风驱雨侵蚀因子与风速和降雨量有关,并随风速及雨强的增加而增加;悬挑屋盖对屋盖附近区域的墙面形成有效的遮蔽作用.     

雪松对降雨截留容量的试验研究

提出了树冠对降雨截留容量的概念,截留容量不仅反映树冠特征对降雨截留作用的大小,还可以用于不同林分之间的比较。通过对雪松树冠截留降雨的观测资料,近似确定出了雪松截留容量与降雨量的关系。借鉴水文学中"流域蓄水容量面积分配曲线"概念,建立了雪松截留容量与降雨量的半经验公式,给出了公式中3个参数的确定方法,经检验效果较好。     

浅谈柠条育苗造林技术要点

柠条（小叶锦鸡儿）属蝶形花科。它适应性强，耐干旱瘠薄，根系发达，萌蘖力强，保水性能好；嫩枝绿叶可作饲料；枝条坚实。发火力旺，湿材也能燃烧。它喜光、耐寒、耐高温，在上方庇荫下生长不良。甚至不能结实，是强阳性树种；冬季能耐-32℃的低温，夏季地表温度达55℃时，不见日灼；能在年降雨量350毫米左右的干旱荒山上形成茂密的灌木林．但在年降雨量250毫米左右的荒山上。不能形成林分，只能稀疏生长。它对土壤要求不严，不论是在水土冲刷严重的石质山地、黄土丘陵．还是风蚀强烈的沙地、荒漠地带，都能生长繁殖。它为深根性树种，侧根发达，荫芽力很强，平茬后可从伐根上发出大量枝条，柠条幼年生长缓慢，第三年后生长显著增快，平茬后生长更为茂盛．是干旱半干旱地区退耕还林及荒山造林的重要灌木树种，也是深受群众欢迎的水保林、薪碳林树种。     

埃及农业蓄水抗旱巧用"尿不湿"

埃及是一个沙漠面积占95%以上的国家,土地资源弥足珍贵.全年平均降雨量不足200毫米,全国不少土地异常干涸,沙漠不断成胁和蚕食着绿洲等可耕地.