基于概率密度分析长江三角洲降水随时间的演变规律

将长江三角洲旱涝等级资料转换成降水概率随时间的演化,揭示了长江三角洲降水概率随时间演变的各层次的分布特征。结果表明：长江三角洲降水存在明显的年际、年代际以及世纪以上时间尺度的准周期变化,而且都超过0.05的信度检验。在530年旱涝等级序列中,虽然长江三角洲各地区发生旱、涝的小概率事件的频数不太相同,但由气候态背景(世纪尺度)所激发的小概率事件频数相同;这一研究结果充分说明作为背景状态的气候演变对小概率事件（干旱、洪涝）的发生具有非常重要的影响,对气候预测理论与提高气候预测准确率具有积极的指导作用。     

湖北省历史时期旱涝灾害的特点与规律分析

通过分析大量的历史文献材料 ,总结了湖北省水旱灾害的发生具有严重性、区域性、季节性、持续性、连锁性、周期性和人为性的特点 .分析了水旱灾害的发生时间变化规律和区域差异 ,特别是严重水旱灾害的时空变化规律 ,认为湖北省大旱与大涝常以交替的形式出现 ,其中水灾明显多于旱灾 ,同时水旱灾害发生的次数有不断增加的趋势 ,2 0世纪以来湖北省已进入大旱、大涝的集中多发期     

基于LST_LAI特征空间的农田干旱监测研究

农田干旱具有范围广且对农业生产影响巨大的特点,对农田干旱的遥感实时动态监测是目前公认的难题。利用MODIS的地表温度(LST)产品和叶面积指数(LAI)产品,构建LST-LAI光谱特征空间,提出温度—叶面积干旱指数(temperature LAI drought index,TLDI)监测农田水分含量,并利用宁夏实测的0～10 cm平均土壤含水量验证该指数的精度,结果表明：它们之间具有良好的相关性,R2的变化范围为0.43～0.86。与TVDI相比,TLDI弥补了作物封垄后TVDI因归一化植被指数(NDVI)饱和对农田水分监测精度降低的缺陷。此外,利用MODIS数据产品LST和LAI进行农田干旱监测,避免了使用MODIS原始数据的繁杂处理过程,初步为MODIS数据产品在农田干旱监测业务化运行探索出一条技术流程。     

水文气象极值事件研究进展

随着经济的增长和人口的增多, 中国对各类气象灾害的脆弱性逐渐增大.同时在全球气候变化的背景下, 水文气象极值事件日趋频繁, 日益成为制约经济社会可持续发展的主要瓶颈.当前水文气象极值事件时空演变特征及其风险评估的研究已受到国内外学者的广泛关注, 本文从干旱、极端降水以及径流变化特征3个方面, 对近年来国内外在水文气象极值事件的研究进展进行分析总结及展望.     

遥感数据在农业旱情监测中的应用研究进展

在全球变暖的背景下,农业干旱频发不仅严重影响区域粮食安全和生态安全,同时还威胁社会经济稳定和可持续发展。农业旱情遥感监测是预防农业旱灾发生发展的重要途径,可以为科学制定旱灾风险管理措施提供有力支撑。因此,厘清农业旱情遥感监测研究进展对于今后更好地开展农业旱情监测及预警研究以及进一步促进社会经济的可持续发展具有重要的现实意义。基于此,系统梳理了当前遥感数据在农业旱情监测中的应用研究进展。针对不同的农业旱情评价对象,将旱情监测指标分为降水监测指标、土壤含水量监测指标和作物需水监测指标,并对不同指标涉及的遥感数据源和评价方法进行了归纳和总结。重点针对农业旱情监测涉及的最主要的两种典型地物（土壤和植被）的光谱特性差异和对水分变化的敏感波段不同,系统总结了微波遥感监测法,可见光、近红外与热红外遥感监测法和高光谱遥感监测法用于农业典型地物旱情监测的近今进展,并探讨了未来农业旱情遥感监测研究的主要发展方向,以期为今后更好地开展农业旱情预警和调控管理工作提供参考。     

Relationship between water use efficiency (WUE) and production of different wheat genotypes at soil water deficit

Through 2-year field experiments, 7 wheat genotypes were better in their field yield. These 7 wheat genotypes and other 3 wheat species, which are being popularized on a large scale in different locations of China, were selected as experimental materials for the sake of measuring their difference in WUE and production and comparing their relationship at soil water deficits, future more, providing better drought resistance lines and theoretical guide for wheat production and practices and exploring anti-drought physiological mechanisms of different wheat genotypes. Under the condition of 3 soil–water–stress treatments (75% field capacity (FC), 55% FC, 45% FC, named level 1, level 2 and level 3, respectively), pot experiments for them were conducted and the related data were collected from their life circle. The main results were as followed: (1) according to the selected soil stress levels, water use efficiency (WUE) of 10 different wheat genotypes was divided into two groups (A and B); group A included genotypes 2, 3, 4, 5, 6, 7, 8, whose WUE decreased basically from level 1 to level 3 and reached individual peak of WUE at level 1; Group 2 included genotypes 1, 9, 10, whose WUE reached their individual peak at level 2; (2) based on total water consumption through all life circle, genotypes 1, 4, 8, 9 had lower water consumption (TWC) at level 1, genotypes 2, 3, 5, 6, 7 lower TWC at level 2, genotype 10 lower TWC at level 3; (3) at level 1, genotypes 2, 3, 4, 5, 6, 7, 8 had higher grain weight of single spike (GWSS), genotypes 1, 9, 10 better GWSS at level 2, which was in good line with individual WUE of different wheat genotypes; (4) by analyzing the indexes related to examining cultivars, it was found that genotypes 1, 2, 3, 4, 5, 6, 9, 10 had longer plant length (PL), spike length (SL), bigger grain number (GN) except genotypes 7 and 8 at level 1, RL was in better line with genotypes 1, 2, 3, 8, 9, 10, but not in the other genotypes at level 1.     

Gordon Research Conference: Isotopes in Biological and Chemical Sciences, 14–19February 2010, Galveston,TX, USA

The natural flow properties of the Yangtze River have been changed completely following the construction of the Three Gorges Dam. The dam's operation has affected the resources and environment in the middle and lower reaches of the Yangtze River, changing the hydrological conditions and ecological environment of the Dongting Lake. During three different dispatching periods of the reservoir, we took triplicate samples of the river and lake water. All the samples were analysed for δ²H and δ¹⁸O to determine the relationship between the lake and the Yangtze River (and other rivers), and to evaluate objectively the influence of the dam's operation on the lake. During the period of water-supply dispatch, the Four Rivers and Miluo River are the main recharge sources of the lake. During the flood-storage dispatching period, the Dongting Lake is recharged largely by the Three Outlets and the Four Rivers, whereas during the period of water-storage dispatch, most of the lake's water originates from the Miluo, Xiang, Zi, and Yuan rivers. Although the Yangtze River only contributes significantly to the lake's recharge through the Three Outlets during the flood-storage dispatching period, the lake discharges large amounts of water into the Yangtze River during all three periods. Through the operation of the reservoir, it should be ensured that the water level of the Dongting Lake is not too low during the dry season, nor too high during the wet season, thus preventing the lake region from future flood and drought disasters.     

梭梭幼苗抗旱性与生物自由基,膜伤害关系初探

梭梭幼苗同化枝的相对含水量和束／自比值随着幼苗生长而增加，渗透势与相对电导率却下降．ＳＯＤ在梭梭幼苗同化枝中的定位表明随着幼苗的生长过程各细胞器中ＳＯＤ的活性也在不断变化，但总趋势是随着生长、细胞质和叶绿体中的ＳＯＤ活性以及总ＳＯＤ活性不断增高，只有线粒体中的ＳＯＤ活性呈现下降趋势。另外梭梭种子的ＳＯＤ活性明显高于子叶和幼苗ＭＤＡ和叶绿素含量以及叶绿素ａ／ｂ的值随着生长在不断增高，相反呼吸速率却降低．