湖南主要土壤酸沉降敏感性初步研究

通过对湖南省主要土壤类型在模拟酸雨条件的敏感性大小进行研究，根据酸害阈值、酸害变化率等敏感性指标，对土壤敏感性进行比较发现，在酸雨pH值大于4．5时，处于土壤酸雨缓冲范围，而当酸雨pH值低于3．5或3时，土壤的pH值变化相当明显。不同土壤母质对酸雨的敏感性表现为：第四纪红土红壤＞砂岩红壤＞花岗岩红壤＞紫色砂页岩红壤；由于垂直地域分异作用，山地红壤的敏感生较大，其次为山地黄棕壤，山地黄壤为不敏感土壤；另外不同土层的敏感差异不明显，受耕作过的土壤酸缓冲性能明显增强。     

暴雨信号发布思路

深圳2000年4月份出现了4次暴雨和大暴雨，其中“4.14”为打破历史纪录的特大暴雨。深圳市气象台所发布的黄、红、蓝色暴雨信号是历史上次数最多，最频繁之一。本文通过对这几次不同量级的暴雨过程中暴雨信号发布情况以及短期天气预报和云图、雷达和自动站等中尺度资料在暴雨预警信号发布中所发挥作用的分析，总结发布暴雨信号的发布思路；并得到十分有益的经验。     

2000年首场特大暴雨过程浅析

本文从天气形势的角度出发，对本次特大暴雨过程进行分析，并统计了物理量场的分布，得到较好的对应关系。在此基础上，结合数值预报产品，对前汛期暴雨的预报提出一些粗浅的看法。     

Effects of collision-induced breakup on drop size distributions in steady state rainshafts

New equations and techniques for dealing with drop breakups are developed and applied to the modelling of the evolution of raindrop spectra in rainshafts. Breakup experiments byMcTaggart-Cowan andList (1975) served as data base.No matter what the original size distribution, the spectrum evolution will always lead to a Marshall-Palmer type equilibrium di tributionN=N ₀e^–D, with =constant andN ₀ proportional to the rainfall rateR. (D stands for raindrop diameter.) ForR29 mm h^–1 and an original Marshall-Palmer distribution, the required fall height to reach equilibrium is 2 km.The equilibrium distributions are characterized by linear relationships betweenR, the radar reflectivity factorZ, the liquid water content LWC and theN ₀ of the Marshall-Palmer distribution. Possible explanations for the discrepancy with observations are given.The fact that the all-water processes cannot produce drops withD2.5 mm (as confirmed by observations) leads to the conclusion that observed large raindrops withD5 mm represent melted hailstones and have not yet reached an equilibrium distribution. These latter conclusions were reached within the original assumption of videspread, steady state precipitation.     

中山市"9·16"特大暴雨分析

本文用各种气象观测资料对2002年9月16日发生在中山的特大暴雨进行了分析.结果表明,这次暴雨发生的主要原因是地面低压环流系统受到西风槽、切变线和低层弱冷空气侵入的影响而在中山附近加强引起的,同时这次特大暴雨降水具有明显的中尺度特征.     

The Analysis of the Seasonal,Spatial, and Compositional Distribution of Humic Substances in a Subtropical Shallow Lake

The spatial and temporal distribution of humic substances in aquatic ecosystems can have important effects on ecosystem productivity, negatively impacting primary productivity while positively impacting secondary productivity. In the present investigation, a large shallow lake ecosystem was studied to determine the spatial and seasonal variation of the composition and concentration of humic substances. Concentrations of total dissolved organic matter, humic acid, and fulvic acid were found to display significant spatial distributions (1.3…13.5 mg/L, DOM; 0.1…5.4 mg/L, HA). The distribution is described by using mapping techniques and the analysis of the spatial distribution of the lake. An analysis of the seasonal variations also indicated the dependence of the occurrence of these compounds on meteorological and hydrological conditions. To identify the potential sources of these organic materials, an analysis was made of the ratio of humic and fulvic acid fractions and total DOM. It was found that areas of high DOM concentration coincided with the areas of highest HA percentage of total DOM. Furthermore using the ratio of the normalised concentrations of HA, FA, and residual DOM (< 5000 g/mol) it was found that areas dominated by each are spatially distinct. This confirms the hypothesis that in these shallow lakes, photodegradation and bacterioplankton activity will create a residence time dependent zonation of each component of the total DOM.     

Origin of Dissolved Organic Carbon Studied by UV‐vis Spectroscopy

Dissolved organic carbon (DOC) distributions in water from Lake Ipê, MS, Brazil, were investigated. The samplings were performed monthly (surface, 1 m depth, and bottom) from June 1999 to June 2000. Absorbance at 285 nm and DOC concentrations in mg dm^—3, p(DOC), were highly correlated for the three depths. 77% of the surface, 85% for 1 m and bottom samples presented a variation between 20 dm³ g^—1 cm^—1 and 50 dm³ g^—1 cm^—1 of A(285 nm)/p(DOC), that characterizes the dissolved organic matter in lake water as essentially fulvic. The ratio A(254 nm)/p(DOC) was also sensitive for fulvic matter, and an A(250 nm)/A(365 nm) = 4 ratio was characteristic of strongly colored waters. The ratios A(436 nm)/p(DOC) for the three depths also showed a significant correlation. The predominance of fulvic acid is explained by environmental characteristics such as the tropical climate, temperatures above 18 °C, and the lake environment. It was demonstrated that the variation in the water carbon content due to different compartments in the lake can be monitored by UV‐vis spectroscopy ratios.     

用GPROF算法反演降水强度和水凝物垂直结构

对NASA应用于TMI的业务降水反演算法(GPROF算法)作了简单分析，并对采用该算法反演的2002年夏季我国湖南常德地区的暴雨结构和2001年7月上旬袭击中国香港地区的尤特台风结构进行了分析。对常德暴雨个例，用地面雷达数据作为实况资料进行了真实性检验。检验结果表明:该算法的整体反演效果较好，可较好地反演常德地区的地面雨强及降水结构，雨区的反演精度与降水性质有关。对尤特台风个例，将反演结果与测雨雷达的反演产品进行了定性比较，结果表明:二者反映的降水结构基本一致；GPROF算法反演的潜热垂直结构也较好地反映了台风的热力结构。最后对算法可能的改进方向进行了讨论。     

Biodegradability of Photographic Developers and Ingredients of Photographic Developers,especially of Hydroquinone and Isoascorbic Acid

The biodegradability of 5 different commercially available common photographic developers and their ingredients hydroquinone, isoascorbic acid, and its sodium salt was determined in parallel using the OECD-screening-test (OECD 301E). The results obtained from the degradation test on hydroquinone were compared with the results of other laboratories. Biodegradability of developers containing isoascorbic acid was in the same range as of comparable products containing hydroquinone.     

重庆市酸沉降污染造成的植被受害状况遥感监测研究

运用遥感技术,对重庆市酸沉降污染造成的植被受害状况进行了全面监测研究。建立了植物遥感监测、植物常规监测以及大气监测结果之间的相关关系。通过彩红外航空遥感调查,划分、圈定并计算了重庆市植被受害类型及其分布面积。