DEVEX-disdrometer evaluation experiment: Basic results and implications for hydrologic studies

Increasing our understanding of the small scale variability of drop size distributions (DSD), and therefore of several bulk characteristics of rainfall processes, has major implications for our interpretation of the remote sensing based estimates of precipitation and its uncertainty. During the spring and summer of 2002 the authors conducted the DEVEX experiment (disdrometer evaluation experiment) to compare measurements of natural rain made with three different types of disdrometers collocated at the Iowa City Municipal Airport in Iowa City, Iowa in the Midwestern United States. This paper focuses on the evaluation of the instruments rather than analysis of the hydrometeorological aspects of the observed events. The comparison demonstrates discrepancies between instruments. The authors discuss the systematic and random effects in terms of rainfall quantities, drop size distribution properties, and the observed drop size vs. velocity relationships. Since the instruments were collocated, the effects of the natural variability of rain are reduced some with time integration, isolating the instrumental differences. The authors discuss the status of DSD measurement technologies and the implications for a range of hydrologic applications from remote sensing of rainfall to atmospheric deposition to soil erosion and sediment transport in the environment. The data set collected during the DEVEX experiment is made available to the research community.     

新一代飞机人工增雨作业指挥系统研制与应用

飞机人工增雨的地面指挥是保证作业安全、科学作业的重要条件,为此研制了具有黑龙江省特色的指挥系统。该系统借鉴了国内同类系统的思路,吸收了其中的优点,突出了多普勒天气雷达资料的应用,决策子系统实现了作业预案的自动生成和输出,通信子系统利用嵌套在电子地理信息系统(GIS)上的实时雷达资料和卫星云图资料跟踪飞机进行指挥,随时根据作业云系的变化调整作业方案,改变飞行航线,达到安全和科学作业的目的。2年的业务运行表明该系统实用、可靠。     

中国人工增雨研究进展

随着全球气候变暖的加剧,水资源短缺问题表现得越来越突出,如何有效地开发利用空中水资源已成为人们关注的热点问题之一。本文回顾了人工增雨的发展历史,概述了当今国内外人工增雨的发展状况,归纳了各地区云状、积云特征、液态含水量、冰晶浓度等云物理特征,并在此基础上对我国各地区尤其是西北地区的增雨潜力进行了分析,最后归纳总结了人工增雨的常用手段、经验和检验人工增雨效果的方法。     

东北冷涡云系人工增雨作业效果的检验和分析

根据辽宁地区的东北冷涡降水天气过程的规律和特点,利用气象台站网的常规观测资料,用事后划分影响区和对比区的移动分区区域回归方法,对东北冷涡降水云系的人工增雨作业效果进行了综合分析。结果表明:(1)辽宁省1992—2004年6~8月对东北冷涡云系人工增雨作业的平均增雨效果为22.44%。(2)有95%以上的可信度证明辽宁省的人工增雨有正效果。(3)物理检验分析证明,作业方法及催化部位基本是合理的,催化作业是有效的。     

“资源一号”卫星星内粒子探测器对扰动事件的观测

本文比较了在太阳平静和扰动时期“资源一号”卫星星内粒子探测器对卫星舱内高能粒子的观测结果，发现在平静时期观测结果很好地反映了辐射带高能粒子在该高度上的分布情况.在扰动时期，粒子探测器观测到高能粒子分布出现重大变化，本文进一步讨论了影响高能粒子在近地空间分布的可能因素.     

小波同态滤波用于南极遥感影像阴影信息增强

介绍了同态滤波方法的原理、实现过程和特点,给出适用的滤波器和表达式,引入基于小波变换的同态滤波方法,采用同态滤波器对小波分解系数进行处理,实现了在保持南极遥感影像总体面貌的基础上增强阴影信息的效果.     

STUDY ON THE CAUSE OF HEAVY RAIN 200506 （HR200506） IN GUANGDONG

A continuous heavy rain visited Guangdong province during June 18-25, 2005 (named Heavy Rain 200506, HR200506) and had resulted in enormous economic loss. The ageostropic Q vectors, θse,meridional circulation, computed from the NCEP reanalysis, and TBB are used to study the rainfall processes. The results indicated that a convective system moved northwards from the South China Sea (SCS)and stayed in Guangdong for several days, which was a direct cause of HR200506. The process is a result of the activity of the South China Sea summer monsoon. There were two rainbands of HR200506 in Guangdong. One laid in the north of Guangdong that produced frontal rainfall; another situated on the south of Guangdong which produced monsoon rainfall.     

Correcting superconducting gravity time-series using rainfall modelling at the Vienna and Membach stations and application to Earth tide analysis

We demonstrate the possibility to improve the signal-to-noise ratio of superconducting gravity time-series by correcting for local hydrological effects. Short-term atmospheric events associated with heavy rain induce step-like gravity signals that deteriorate the frequency spectrum estimates. Based on 4D modeling constrained by high temporal resolution rain gauge data, rainfall admittances for the Vienna and Membach superconducting gravity stations are calculated. This allows routine correction for Newtonian rain water effects, which reduces the standard deviation of residuals after tidal parameter adjustment by 10%. It also improves the correction of steps of instrumental origin when they coincide with step-like water mass signals.     

Photobleaching of chromophoric dissolved organic matter (CDOM) in rainwater

Significant photodegradation of chromophoric dissolved organic matter (CDOM) in rainwater was observed after exposure to simulated sunlight. Fluorescence excitation emission spectra (EEMS) of precipitation revealed the presence of four major peaks all of which degraded upon photolysis with the greatest loss in the region characteristic of marine CDOM. Photobleaching of absorbance also occurred in the wavelength region between 250 and 375 nm with the greatest loss of absorbance in the upper end of the UV-A region near 275 nm. There was a strong positive correlation between absorbance loss and total integrated fluorescence loss suggesting these optical properties and the degree to which they are photobleached in rainwater are directly related. The quantum yield of CDOM photodegradation in rainwater decreased dramatically with increasing wavelength and decreasing energy of incoming radiation with the average quantum yield at 325 nm approximately an order of magnitude greater than at 460 nm. The similarity of photolytic response between rainwater and Cape Fear estuarine CDOM indicates that some fraction of the compounds that make up rainwater CDOM may be derived from surface sources and/or that the processes that produce or modify humic-like substances in the atmosphere result in similar types of compounds as non-atmospheric processes.