基于ERA-Interim资料的中国天山山区云水含量空间分布特征

利用欧洲数值预报中心(ECMWF)发布的第一代全球分辨率ERA-Interim再分析数据,分析了1979—2014年天山山区水汽含量和云水含量的空间分布特征。结果显示:(1)水汽含量的高值中心出现博罗科努山迎风坡,中心值域在10~11 mm之间,低值区位于天山中部的巴音布鲁克附近,中心值域在5~6 mm之间;夏季水汽含量最丰富,在8~11 mm之间。(2)云液水含量的高值区出现在博格达山北坡,而云冰水含量的高值区在西天山海拔较高的托木尔峰地区,低值区均在伊犁河谷等海拔低的地区;夏季云液水含量、云冰水含量均呈减少趋势,云冰水含量较云液水减少得更为明显,下降速率为0.28×10-3 g·kg~(-1)/10 a;(3)垂直分布上,云液水含量在600 h Pa左右的高空出现高值区,中心最大值为10×10~(-3) g·kg~(-1);云冰水含量的高值区则出现在500 h Pa左右的高空,为11×10~(-3) g·kg~(-1);在对流层大气中云冰水含量值远大于云液水,且云冰水发展的高度较云液水更高。     

基于ERA-Interim资料的青海省空中云水资源评估

利用ERA-interim再分析资料分析2009—2018年青海省云液水含量和云冰水含量时空分布特征。结果表明:青海省云液水含量和云冰水含量自西北向东南逐渐增多,玉树南部、果洛东南部和祁连山区为云水资源较为丰富的地区,夏秋季节云水资源最为丰富,可达60～70 g·m~(-2)。从云水资源的垂直分布来看,云液水含量和云冰水含量随海拔高度增高呈先增多后减少的变化趋势,云液水含量在海拔4～6 km高度较多,云冰水含量在海拔7～8 km高度较多,云冰水含量峰值所在高度高于云液水含量峰值所在高度。夏秋季节,青南高原云液水含量和云冰水含量垂直变化幅度大,柴达木盆地云液水含量和云冰水含量垂直变化幅度小。从年际变化趋势来看,2009—2018年青海省大部地区云液水含量、云冰水含量呈增多趋势,且秋季增多趋势最为显著。从月际变化看,云液水含量和云冰水含量9月最高,1月最低。柴达木盆地云液水含量和云冰水含量的月际差异最小,东部农业区云液水含量月际差异最大,青南高原云冰水含量月际差异最大。     

地基微波辐射计探测空中水个例分析

为了解层状云降水天气过程中水汽、液水含量的变化 ,在西安地区利用双波长地基微波辐射计进行空中水汽、液态水的连续探测。通过对 2 0 0 3 - 0 9- 1 7的层状云降水天气过程跟踪探测 ,分析得到空中水汽、液水含量的变化特征 :在降水开始前 5 h,水汽、液水含量出现低值段     

用微波辐射计作云降水潜力的估算

1997年7—11月，用单点双波长地基微波辐射计对西安上空的降水云作汽态水、液态水的连续探测，分析发现云中水汽和液水含量在降水开始前有明显变化。将变化的时间轴转化成空间轴，得到：在云的降水区前有一较宽的液水含量高值区，在高值区和降水区连接处存在一液水含量低值区。云的总降水量与高值区的水汽和液水含量值有一定关系，参数Rk代表云的可降水潜力，当Rk大于2．7时，云才有被人工催化增雨作业的潜力；Rk大于3．5时，人工增雨效率最高。     

基于CloudSat卫星分析西太平洋台风云系的垂直结构及其微物理特征

基于2012—2014年CloudSat卫星数据,按照热带气旋强度分类的6个等级以及沿台风中心的径向距离,分析西太平洋台风云系的垂直结构及其微物理特征。研究表明:(1)不同强度的台风云系中均是单层云占主导,多层云中双层云出现比例最高;随着台风强度的增强,距离台风中心250km之内,单层云分布位置更加集中且垂直厚度较厚,而450km之外的单层云一直集中在7~15km,厚度较薄;随着台风强度的增强,距离台风中心250km之内的双层云中的底层云和顶层云均增厚且分布位置更加趋于集中,云间距变窄,而450km之外顶层云和底层云较薄,云间距一直较大。(2)台风云系中,深对流云、高层云、卷云与其他云类型相比,分布的垂直范围较广,出现频率较高,分布的位置会随着台风强度变化和沿台风中心径向距离的增加有明显的变化。(3)随着台风强度的增强,近台风中心5km以上的回波有明显增强,除此高值区外,发展较为成熟的台风,距台风中心450km之外也会出现多个明显的柱状回波高值区。(4)近台风中心液水含量的值和冰水含量的值随强度变化均有明显增加,但外围云系中也有分散的冰水含量高值中心但分布高度相对较低,在10km附近;液水粒子数浓度的高值区域与液水含量的高值区非常对应,而冰水含量的高值区位于冰粒子数浓度的高值区下方,表明小的冰粒子被较强的对流活动带到了高处,而大的冰粒子集中在云系较低处。     

基于CERES资料的中国西南地区云水含量和粒子有效半径分布及变化特征

利用NASA/CERES发布的2001～2015年云参数资料,选取高层云、雨层云、层积云的云水含量和云粒子有效半径,统计分析了西南地区云参数的时空分布特征和变化趋势。结果表明:从年均空间分布来看,西南地区液水和冰水含量均东部高于西部,海拔低的地区高于海拔高的地区;高层云和雨层云液相和冰相云粒子有效半径在川西高原最大。从数值大小来看,雨层云液水和冰水含量最多,分别介于90～230 g/m2和100～300 g/m2,层积云最少,分别介于0～80 g/m2和0～60 g/m2;冰相云粒子有效半径高于液相2～6 μm。从季节分布来看,雨层云液水和冰水含量秋季和冬季偏高,夏季和春季偏少,高层云和层积云季节差异较小;液相云粒子有效半径均夏季最大。从变化趋势来看,西南地区各地液水和冰水含量均呈减少趋势,液相和冰相云粒子有效半径有呈减少或增加趋势。     

二维粒子形状分类技术在云微物理特征分析中的应用

本文介绍了一种针对飞机粒子探测系统中云二维图像探头开发的二维粒子形状分类技术。该技术利用粒子形状几何参数特征把云粒子分为8种类型,分别为微小状、线形状、聚合状、霰状、球状、六角形状、不规则状和枝状。同时结合冰水质量关系,给出了探头液水含量和冰水含量的计算方法。最后应用该技术对2006年4月6日一次飞机探测获取的数据进行了云微物理结构分析,聚合状、霰状、六角形状、不规则状的总出现频率为78%,其中霰状粒子的出现频率随着温度的降低而增加。非降水云中的液水含量、液滴粒子浓度、冰晶浓度明显小于降水云,非降水云中液水含量的平均值为0.01 g m-3,冰水含量的平均值0.007 g m-3,冰晶粒子浓度的平均值为11.9 L-1。     

基于微波辐射计数据的秦岭南北水汽和云底高度等参量的差异

利用微波辐射计分析了秦岭南北的水汽、液态水含量、湿度、云底高度等特征,结果表明:秦岭北垂直积分水汽量年平均为18.52 kg·m-2,秦岭南为20.94 kg·m-2,90％以上水汽秦岭北平均高度为4.26 km,秦岭南为3.87 km;垂直积分液水含量,秦岭南年平均为0.13 kg·m-2,秦岭北年平均为0.12 k...     

西北地区不同类型云的时空分布及其与降水的关系

利用1983年7月～2001年9月国际卫星云气候计划ISCCP D2的月平均资料，对西北不同区域不同类型云的云量和云水路径的时空分布及其与降水的关系进行了研究。结果表明:高原气候区是各种云出现最多的地区，特别是积状云的云量明显高于其他两区，但这些云的云水路径值低；西北地区大多数云云量的高值区出现在天山山区、北疆地区、陕西东南部和青藏高原的部分地区。高云和部分中云云量空间分布特征与降水有着较好的一致性:沿着天山—昆仑山—祁连山一带以及陕南和／或陇南地区是高值区，低值区在塔里木盆地—内蒙古西部戈壁沙漠—黄土高原西北部一带；绝大多数云类春夏季节云量维持较高，秋冬季节云量较少。云水路径值较大的层状云类的云量多寡与降水多寡相一致；积状云类和层积云类云量多少与降水没有一定的关系，在降水偏少时，这类云的云量大多与降水正常时相近，有些云的云量甚至比降水偏多时还要多。     

西北地区空中云水资源的时空分布特征

利用1983年7月至1998年12月国际卫星云气候计划ISCCP D2的月平均云资料,对西北地区空中云水资源的时空分布特征进行了系统的研究。结果表明:三个不同区域的月平均总云量、光学厚度和云水路径的区域平均值分别在52.5%~58.3%,2.6~6.6和44.9~77.6 g.m-2之间;西北地区空中云水资源多年平均分布有其沿地形分布的特点,总云量、中云量、总光学厚度和总云水路径的高值区均在天山、昆仑山、祁连山一带,而低值中心一般分布在塔里木盆地—内蒙古西部戈壁沙漠—黄土高原西北部一带。此外,祁连山、青海所在的高原气候区云水资源近年呈上升趋势,特别是总光学厚度和总云水路径15年来呈明显上升趋势,分别约上升了0.8和16.4 g.m-2。     

Water erosion control

Under natural conditions, balanced ecological systems develop in which the soil is protected by a cover of different plants. When man modifies the environment, in his attempts to produce more food, fiber and fuel, the ecological system is changed.This often results in the soil being exposed to the processes of accelerated water erosion. In this way, millions of hectares of land, particularly in the semi arid areas are now eroding.This paper stresses that the most important principle in controlling water erosion is to develop a new balanced system which is not only productive but which is also stable.Water erosion control schemes should therefore be based on the selection and introduction of correct land use.Examples are given of the types of measures that may be needed for cultivated, grazing and forestry lands.In some cases, a change in land use may also have to be supported by the construction of physical conservation measures. Some common examples of such measures are briefly described.     

Global Warming and Water Management: Water Allocation and Project Evaluation

This paper explores the sensitivity of the benefits of alternative water allocation schemes and of project evaluation to global warming. If global warming shifts the mean of annual water supplies, there could be large impacts on the expected values of alternative water allocation schemes. The first section of the paper explores how well alternative schemes (such as market mechanisms, prior rights, or percentage flows) perform if the distribution of flows changes. In a case study of the Colorado River, market mechanisms and flow guarantees result in smaller impacts than rules which allocate inefficient percentages of flows to heterogeneous users. The second part of the paper explores the effect of a gradually changing distribution of flows on project evaluations. Project evaluation is sensitive to predicted future changes in mean flows. Project evaluation is not sensitive to changes in the variance of future flows unless the variance increase is large and the benefit measure is highly curvilinear. Because basin-specific changes in runoff from global warming are currently uncertain and much delayed, most project analyses will be unaffected by global warming. The most important response by water managers to climate change may simply be to closely monitor runoff and incorporate flexible rules in order to adapt their behavior to observed changes.     

区域水资源配置中供水预测计算方法研究

供水预测是区域水资源配置中的重要组成部分,供水预测结果直接决定着水资源配置结果。由于常规的预测方法不能适应区域的实际情况,因此在考虑水质和水权条件下,定义了可供水量概念,并结合区域实际情况,提出以可供水量预测为基础的供水预测的实际计算步骤和方法及遇到实际问题的解决方法。由该方法对新郑市供水进行预测,预测结果符合实际,可为新郑市水资源配置及水系规划提供参考依据。     

大气水分循环方程

任何地点的降水量可能来自地球的任何地点的水分蒸发。为了定量描述大气中的这种水分循环的复杂过程,我们引入了两个概念性的工具:大气水分辐合函数和大气水分辐散函数,并且建立了用它们描述大气水分循环的方程组。     

Island Wakes in Shallow Water

Island wakes in shallow water are investigated using the Regional Ocean Modeling System (ROMS). In contrast to deep water where bottom stress can be neglected in island wakes, shallow water implies that inhomogeneity in the bottom stress plays an important role in the wake vorticity generation. A series of numerical experiments are conducted to investigate wake formation and evolution in shallow water. It is found that the vertical structures of shallow-water and deep-water wakes are significantly different because of the presence of a density frontal jet, which results from the interaction between stratification and bottom topography. The frontal jet reaches its maximum within the bottom boundary layer over the shelf, giving rise to vorticity. The potential vorticity (PV) balance analysis reveals that frictional and diapycnal processes play different roles in the PV anomalies. With the absence of lateral stress (i.e., a sea mountain case), the surface vorticity becomes much weaker than that in the presence of an island.     

Assessing Urban Water Use and the Role of Water Conservation Measures under Climate Uncertainty

There has been substantial analysis of the possible impact of climate change on water supply, especially with respect to runoff and river flows. Less attention has been given to urban water use. Little is known of the suitability of various water use forecasting models for predicting climate impacts or of the best procedures for assessing this issue. This paper will: (1) demonstrate the feasibility of a scenario approach to describing possible changes in climate, (2) evaluate the IWR-MAIN model as a source of plausible water use forecasts given uncertain future climate, (3) test the effectiveness of conservation and pricing interventions in reversing the postulated effects of climate change, and (4) assess the significance of climate change for future urban water management. Other possible responses to climate change, such as supply augmentation, are not explicitly considered. Using data for the Washington (DC) metropolitan area, the study reveals problems with IWR-MAIN version 5.1 when used for this purpose, but results in a reasonable assessment of the possible water use consequences of climate change. Variation in future water use due to climate uncertainty was found to be moderate compared to other uncertain influences, and well within reach of feasible policy interventions.     

Climate and Water: From Climate Models to Water Resources Management and Vice Versa

This article reviews the recent developments in the functional chain from climate models to climate scenarios, through hydrology all the way to water resources management, design and policy making. Although climate models, such as Global Circulation Models (GCMs) continue to evolve, their outputs remain crude and often even inappropriate to watershed-scale hydrological analyses. The bridging techniques are evolving, though. Many families of regionalization technologies are under progress in parallel. Perhaps the most important advances are in the field of regional weather patterns, such as ENSO (El Niño-Southern Oscillation), NAO (North Atlantic Oscillation) and many more. The gap from hydrology to water resources development is by far not that wide. The traditional and contemporary practices are well in place. In climate change studies, the bottleneck is not in this link itself but in the climatic input. The tendency seems to be towards integrated water resources assessments, where climate is only one among many changes that are expected to occur, such as demography, land cover and land use, economy, technologies, and so forth. In such a pragmatic setting a risk–analytic interpretation of those scenarios is often called for. The above-outlined continuum from climate to water is a topic where the physically based modelers, the empiricists and the pragmatists should not get restricted to their own way of thinking. The issues should develop hand in hand. Perhaps the greatest challenge is to incorporate and respect the pragmatic policy-related component to the two other branches. For this purpose, it is helpful to reverse the direction of thinking from time to time to start—instead of climate models—from practical needs and think how the climate scenarios and models help really in the difficult task of designing better water structures, outline better policies and formulate better operational rules in the water field.     

E601B型蒸发器观测后加水与汲水问题分析

针对台站E601B型蒸发器观测后加水与汲水的问题,通过分析,找出主要原因是蒸发器蒸发桶内标准水面高度的位置确立,是解决问题的关键所在.     

利用双频微波辐射计测空中水汽和云液水含量的个例分析

利用23.8GHz和31.65GHz双频地基微波辐射计观测资料,结合卫星云图、雷达、探空和自记雨量计等资料分析了2005年4月在河南新乡观测的不同云系影响时大气垂直积分含水量(V)和云中液态含水量(L)的演变特征,对4月8日低槽云系影响时V、L的特征进行了分析。结果表明:双频辐射计对空中水汽和液态水反映灵敏,不同天气背景时对应有不同的V、L值分布。云液水含量L的变化与云量的增减有关。降水开始之前,水汽含量V值有明显波动,液态水含量L值也有明显增加,一般增大到0.4mm时即出现降水。这些现象对降水开始有指示意义,可预测云系正处于降水产生的阶段,可应用于人工增雨作业。此外,根据微波辐射计观测资料分析了大气水汽、云液水和地面降水之间的定量关系,云中液态水仅占汽态水的8.7‰左右,落回地面的降水占空中水汽量的18%左右。