北京冬夏降水系统中的云水量及其统计特征分析

根据地基双通道微波辐射计观测的降水天气下大气水汽、液水含量的变化 ,分析了北京1 989年夏季 1次降水过程和 1 990年冬季 5次降雪过程的云水量资料 ,讨论了降水过程中汽态水和液态水含量的一些统计特征及其随时间的变化 ,并估算了夏季降水中凝结水向降水的转化率。结合极轨气象卫星的遥感云顶温度资料 ,以及冬季地面降雪强度的观测 ,对北京冬季降水系统中的液水含量与降水的相关进行了分析 。

西南地区云水量与可降水量比值的分布特征和变化趋势

采用1980～2009年云水量和可降水量的NCEP逐月再分析资料，通过统计分析，研究30a来西南地区（云南、贵州、讴庆、四川）云水量与可降水量比值的时空分布特征和变化趋势。结果表明：（1）西南地区年、季17孟水量与可降水比值均具有明显的地区性差异，由西北向东南递减，高值区位于川西高原；（2）云水量与可降水比值年内分布不均匀，从2月到8月逐渐减小，9月至1月逐渐增大，同时，季节差异较大，夏季最小，冬季最大；（3）30a来，整个西南地区年、夏季和秋季云水量与可降水量比值呈显著减少趋势。

西南地区空中云水量分布特征及变化趋势

为了能更好的合理开发空中水资源,采用NCEP 1980～ 2009年云水量的逐月再分析资料,通过统计和EOF分析等方法,研究了30年来西南地区（云南、贵州、重庆、四川）云水量的时空分布特征和变化趋势.结果表明：西南地区年和季节云水量分布均具有明显的地区性差异,东南多,西北少,最小值出现在四川西部高原地区;云水量在夏季最多,春季略高于秋季,冬季最少;逐月云水量呈近似的正态分布,1月到6月逐渐增加,7月到12月逐渐减少;西南地区云水量的空间变化既存在南部与北部相反的变化趋势,也存在整体一致型.

基于ERA-Interim的中国云水量时空分布和变化趋势

利用欧洲中期天气预报中心(ECMWF)发布的新一代全球分辨率ERA-Interim再分析数据,用九点平滑、一元线性回归法分析了1979-2016年中国云水量时空分布特征和变化趋势。结果表明:(1)中国云水含量和云液水含量大值区主要位于四川东部-湖南850～500 h Pa,量值达0. 015～0. 045 g·kg^(-1),这一分布与该地区层状云的富集有关。云冰水含量大值区主要位于中东部地区(27°N-35°N,97°E-110°E) 500～250 hPa,量值达0. 006～0. 025 g·kg^(-1)。三者小值区均位于西北地区西部。(2)中国多年平均整层云水量无明显线性趋势。春季云水量呈略减少,秋、冬季呈略增加趋势,夏季无明显趋势。云水量有明显年际变化,夏季年际变化远小于其他季节;干旱区、半干旱区整层云液态水含量的年际变化大于湿润区,云冰水含量相反。云水量空间变化呈西增东减趋势。(3)云水量大值区对应水汽输送辐合和低层上升运动,且对流层中低层水汽通量散度可在一定程度上表征云水含量。从而为认识和理解气候变化对中国水资源的影响提供一定依据。

全球云水量气候分布及变化趋势特征分析

采用20世纪再分析版本2c数据集的云水量逐月再分析数据,通过数理统计方法,分析了1960~2014年全球、海洋和陆地上空云水量的分布和变化特征及其与水汽通量的关系。结果表明:1)全球云水量空间分布不均,海洋高于陆地且比例约为4﹕3,中低纬海洋、陆地上空云水量变化趋势分别为0.07 g m^(−2)(10 a)^(−1)和−0.04 g m^(−2)(10 a)^(−1),季节性差异主要体现于夏季在热带辐合带和南半球海洋高,冬季在北半球海洋和南半球陆地高。2)对比六大洲发现,云水量最高的南美洲有最快增加趋势,为0.46 g m^(−2)(10 a)^(−1),同时云水量最低的非洲有最快降低趋势,为−0.59 g m^(−2)(10 a)^(−1)。3)中低层整层水汽通量散度场的辐合、辐散区和云水量的高、低值区相对应,云水量与水汽通量散度变化呈负相关(相关系数为−0.44),负相关关系在赤道附近的低纬地区显著。本文揭示了在全球变暖背景下,大气中云水量分布和变化的时空格局,为模式参数化和未来气候预估提供参考。

近21年丹江口流域空中云水量特征及与面雨量的关系

利用2001~2021年丹江口流域降水资料及MODIS云水路径产品,采用统计方法分析地面降水与空中云水的时空演变特征及相关关系。结果表明:(1)近21年丹江口流域面雨量略有增加,空间分布西南多东北少、季节特征显著。(2)丹江口流域平均液水路径小于300 g/m^(2),季节变化不明显,空间差异不大,与反演算法的局限性有关;而平均冰水路径和云水路径分别为150~500 g/m^(2)和250~750 g/m^(2),均在夏季出现峰值、季节特征与面雨量吻合,且由于受地形影响、地域分布特征明显。定量分析显示,云水路径与面雨量存在较好的相关性(相关系数为0.73)。(3)丹江口流域冬季云水更新周期较长,12月可达34.5 h,夏季云水循环较快,7月云水更新周期仅为2.7 h。

祁连山区云光学特征的遥感反演与云水资源的分布特征分析

利用Terra和Aqua卫星上载的MODIS探测器接收资料和祁连山区及周边气象台站6 h降水量资料, 应用6S辐射传输模式和Mie模式, 针对2002-2005年以来的18次大范围云覆盖的祁连山区, 反演了云的光学厚度、云粒子有效半径以及云液态含水量等参数, 结合地理信息系统分析了其随海拔高度变化的分布特征及其与地面降雨量的关系. 结果表明： 祁连山区云的光学厚度、云粒子有效半径以及云液态含水量分布受地形影响具有显著的地域差异, 最大值分布在海拔4 300 m以下的山区, 是云水资源丰富区和易降水区; 云宏观特征参数与地面6 h降水量成正相关关系, 产生降水概率较大的云光学厚度在8～20之间, 云粒子有效半径在6～12 μm之间, 云液态含水量在0.04 g·m^-3就能产生降水. 祁连山区云液态含水量可高达0.15 g·m^-3, 表明山区云水资源具有很大的开发潜力.

碘化银消除过冷低云试验结果

给出了用碘化银(AgI)消除过冷低云时微物理量随时间演变的详细过程。飞机播撒 AgI 后,云滴数浓度不断减少,对应的云含水量随时间呈指数衰减;冰雪晶数浓度不断增加;由于冰雪晶凝华、撞冻、聚并导致冰雪晶尺度谱明显拓宽,最大雪晶尺度可达5400μm。这些过程并非瞬时发生而是缓慢进行的,一般在播撒后5分钟才有明显变化。

石家庄地区一次秋季冷锋云系垂直微物理结构的观测研究

利用2008年10月4～5日石家庄一次降水性层状云系的飞机探测资料,结合实时天气、卫星、雷达等资料,分析了降水过程的天气背景条件、降水初期云中的液态含水量、云粒子平均直径和粒子谱等要素的垂直分布与变化特征,以及云系的垂直微物理结构。结合云中冰雪晶二维粒子图像的增长和地面降水特征,初步探讨了该层状云系降水形成的物理机制。结果表明,此次降水为北方秋季典型的较稳定性冷锋降水过程,云系由高层卷云、中层高层云、低层层积云组成,垂直结构特征明显;云系微物理要素的垂直分布结构与粒子增长过程符合顾震潮先生的三层模型的冷云降水形成机制。

机载近红外偏振激光雷达探测过冷云研究

针对过冷云分布的探测,设计了一种近红外机载偏振同轴微脉冲激光雷达系统。该系统采用波长1550 nm激光激励,可有效减少云中小尺度气溶胶粒子的消光,从而提高大尺度云粒子的探测距离和效率。通过非球形粒子的退偏比来甄别云粒子相态,同时提出了云含水量的激光雷达反演算法,并结合机载温度数据和对流层特征,反演过冷云的空间分布。基于标准大气模型和机载仪器的云粒子谱数据,仿真分析了不同激励波长偏振微脉冲激光雷达在两种对流层云中的探测性能,结果表明下层云中的探测距离约为1.1 km,而上层云中的探测距离可达1.5 km。

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。

鄂东南夏季积状云的雨滴谱特征

通过对鄂东南夏季积状云雨滴谱资料的计算分析,得到了此地积状云的降水历时、滴浓度、云含水量等参数,对滴谱谱型、降水过程中的谱型变化特征进行了研究,拟合降水强度与含水量、降水强度与滴浓度关系发现,前者比后者关系要好,它们分别呈指数关系.

山东省春秋季降水系统的云物理概念特征

山东省春秋季降水既受南方天气系统的影响，又受北方天气系统的频繁作用，降水过程较为复杂。本文通过对不同天气系统的分析表明，北方天气系统的降水微物理过程基本符合Ｂｅｒｇｅｒｏｎ提出的催化云－洪水云相互作用导致降水的总体概念。本文给出了南、北天气系统降水的概念特征，降水过程在北方天气系统个例中均通过冰晶过程（冷雨过程）发动；南方天气系统中难以通过云水的自动转化形成有效的降水，可以将这类系统中高空云带中存在的过冷水作为冷雨过程的供水云进行催化。

毫米波测云雷达在晴雨观测中的初步应用

利用平和县气象观测站2018年8~11月地面观测资料,结合毫米波测云雷达的观测结果,初步分析了回波强度、云含水量和云场分布在晴雨观测中的应用。结果表明,晴天回波强度在-39.3^-5.3dBz,云含水量0.1g/m^3,以层云和层积云为主。多云和阴天回波强度增大,回波中心达-5.3~17.3dBz,云含水量1.0~2.0g/m^3,以层云、雨层云和层积云为主。雨天回波强度17.3~27.8dBz,呈片状分布,云含水量1.5~2.5g/m^3,积雨云深厚且覆盖全天空,回波强度和云含水量中心出现时间与地面降水时段相吻合。

台风远距离影响下的大暴雨对流涡度矢量分析

利用常规观测资料、NCEP再分析资料、自动站资料和卫星云图资料,对2010年7月16—19日台风远距离影响下的川陕大暴雨天气过程从对流涡度矢量进行诊断分析。结果表明:高θe区位于西南涡偏南侧暖湿气流端,大暴雨区即位于此处;大暴雨中心等θe线随高度近于垂直分布,θe高值区呈"漏斗"状结构,从低层到对流层顶均为90%的相对湿度。东北—西南向的倾斜高空急流加强了急流入口区右侧的高层辐散,造成大暴雨区强而深厚的垂直上升运动。强降水中心低层为东南风,中层为西南风,高层为西北风,对流不稳定性很大;西风分量u在中层垂直切变较大,南风分量v在中高层垂直切变较大。大暴雨出现在对流涡度矢量(CVV)垂直分量和气柱云水量二者大值重合区。

Effect of Reducing Chemical Fertilizer on Rice Yield,Output Value,Content of Soil Carbon and Nitrogen after Utilizing the Milk Vetch

A located field experiment was carried out to study the effects of different amount of chemical fertilizer usage on rice yield,economic benefits of rice,soil carbon（C） and total nitrogen（TN） under ploughing back of Chinese milk vetch for 5consecutive years.Six treatments were included in the experiment,they are CK（unfertilized）,CF（100% chemical fertilizer with the amount of N,P2O5,K2 O being150,75,120 kg/hm^2respectively）,A1（22 500 kg/hm^2 Chinese milk vetch and 100%chemical fertilizer）,A2（Chinese milk vetch and 80% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A3（Chinese milk vetch and 60% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A4（Chinese milk vetch and 40% nitrogen and potassium fertilizer and 100% phosphate fertilizer）.The results were as follows：application of fertilizer could increase the yield of rice,while Chinese milk vetch combined with fertilizer application had a much more increase effect in rice yield.Under the condition of milk vetch application with 22 500 kg/hm^2,the early rice yield of the treatment A1 was significantly increased by 7.7% compared with that of CF.And the yield of treatment A3 was basically identical to or slight increase in comparison with that of CF.Decreasing amount of fertilizers cloud improve output value of rice in the case of the utilization of Chinese milk vetch.The treatment A1 increased output value of rice by 5.92% in comparison of CF,and treatment A2 was by 4.08% in the next.Treatment A4 showed much better effect in increasing soil organic carbon and total nitrogen in the paddy soil than those of treatments applying mineral fertilizer only.There was a significant reduction on soil organic carbon and TN in treatment A2 in comparison with that of CF.In general,amount of application of milk vetch with 22 500 kg/hm^2 could replace chemical fertilizer partially,it also could improve rice yield,decrease the production cost,and raise the utilization efficiency of nutrients.

Effects of Ploughing Astragalus sinicus at Maturity Stage on Rice Yield and Soil Properties of Paddy Field

[Objective] The effects of ploughing Astragalus sinicus at maturity stage as green manure on paddy soil properties were studied to provide references for ad- vancing the green manure production and field sustainable development. [Methods] A three-year field positioning experiment was carried out. In the first year, five differ- ent levels （0, 2.81, 5.61, 8.42, 11.23 t/hm~） of Astragalus sinicus ploughed at matu- rity stage were designed. And in the next two years, the amounts of ploughed As- tragalus sinicus at maturity stage were based on the natural growth amounts of As- tragalus sinicus at maturity stage of the former year in each plot field. The yields of Astragalus sinicus at maturity stage were estimated and ploughed directly before rice transplanting. Rice yield, soil nutrients, biological properties and water-stable aggre- gates of paddy fields were measured as well. [Results] The effective panicles and rice yields increased significantly after ploughing Astragalus sinicus at maturity stage. Meanwhile, the organic acid content in paddy field increased and the activities of soil phosphatases, invertase and catalase were higher. The soil dissolved organic carbon also increased with the increasing application of green manure. However, excess amount of green manure inhibited the soil microbial biomass carbon content. The macro aggregates and micro aggregates gathered to middle aggregates. [Conclusion] As green manure, the use of Astragalus sinicus at maturity stage could improve soil physiochemical and biological properties, improve soil fertility and increase rice yield significantly. But the ploughing amount of Astragalus sinicus at maturity stage before rice transplanting should be less than 8.42 t/hm2 （dry weight.

Energy Consumption in Comminution of Mica with Cavitation Abrasive Water Jet

We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.

Analysis of Variation Characteristics of Sunshine in Recent 56 Years in Huanren Area

On the basis of 56 years of measured data concerning sunshine duration in Huanren County, the decadal, annual, seasonal, and monthly variation characteristics of sunshine duration in recent 56 years and its relationship with relative sunshine, total cloudiness, lower cloudiness and water vapour pressure in Huanren area are interpreted in this paper. It demonstrates that the annual, seasonal and monthly sunshine duration show a decreasing trend, decreasing with rapidest speed in spring and slowest speed in winter. The sunshine hours in each month in Huanren area tend to decline, among which the decreasing trend is more obvious in May and less in February. The annual variation of sunshine duration is consistent with sunshine percentage. Sudden change of sunshine duration occurred around 1992. Annual low cloudiness and vapour pressure are slightly increasing. The significantly negative correlation exists between sunshine hours and low cloudiness, and total cloud cover and water vapour pressure are the major factors responsible for decline in sunshine hours in Huanren area.

Characterization of cloud microphysical properties in different cloud types over East Asia based on CloudSat/CALIPSO satellite products

By using four-year CloudSat/CALIPSO satellite data,the authors investigated cloud microphysical properties in three representative regions over East Asia,where models commonly suffer from great biases in simulations of cloud radiative effects.This study aims to provide an observational basis of cloud microphysical properties for the modeling community,against which the model simulations can be validated.The analyzed cloud microphysical properties include mass,number concentration,and effective radius for both liquid and ice phases.For liquid clouds,both cloud mass and number concentration gradually decrease with height,leading to the effective radius being nearly uniformly spread in the range of 8-14μm.For ice clouds,the cloud mass and effective radius decrease with height,whereas the number concentration is nearly uniform in the vertical.The cloud microphysical properties show remarkable differences among different cloud types.Cloud mass and number concentration are larger in cumuliform clouds,whereas smaller in cirrus clouds.By comparing cloud properties among the Tibetan Plateau,East China,and the western North Pacific,results show the values are overall smaller for liquid clouds but larger for ice clouds over the Tibetan Plateau.