Evaluation of Drought Hazard Area of GharehAghaj Basin in Iran, Using GIS

In GharehAghaj basin drought has the most profound effect on the way of living and regional economy. Drought Hazard by nature is a result of interrelated parameters concerned. The objective of this paper presents a model to assess hazard of drought using the Geographical Information System (GIS). The data analyzed have been gathered from the records, reports and maps published by the governmental offices of Iran. Various drought hazard indicators have different severity classification in different models. The drought hazard indicator maps take into account the meteorological, hydrological, physical and socioeconomic characteristics that related to drought hazard. Each of the hazard indicator maps and also final hazard map are classified into 4 hazard classes of drought: mild, moderate, severe and very severe. The final hazard classes were defined on the basis of hazard scores arrived at by assigning the appropriate attributes to the indicators and the final hazard map was prepared by overlaying different hazard indicator maps in the GIS, deploying the new model. The final Hazard Map shows that moderate hazard areas (89.87% of the basin) are much widespread than areas under severe hazard (10.13% of the basin) which are observed in the Southeast of the region.

渭北旱原农田承灾力综合评价

陕西省渭北地区旱原农田旱灾承受力的综合评价，选取了１６项参评指标，采用层次评判法对该地区２３县（市）及该地区不同耕作制度区的农田旱灾承受力作了综合评价。

1961—2010年中国旱灾时空分布特征研究

采用《中国统计年鉴》和中国农业灾情数据库中的统计资料，重建了1961—2010年中国旱灾的时空分布特征．通过对旱灾时间分布特征的研究结果表明，近50年我国的干旱化程度呈上升趋势．干旱的时间分布存在几个明显的高值区和低值区，旱灾严重年份大多分布在高值区内，旱灾较轻年份大多分布在低值区内．对旱灾空间分布特征的研究结果表明，中国旱灾的空间格局存在东西分异，且以东部型为主．旱灾在不同省（市、区）的分布有很大的差异，山西、河北、内蒙古、山东等省份的旱情比较严重．另外，中国各区域旱灾的季节分布差异也很大，东北、华北和西北地区多发生春、夏旱，长江中下游地区多发生夏、秋旱，华南和西南地区多发生冬春连旱，青藏高原地区的干旱主要发生在5—7月和10月．

武陵山地区干旱时空特征分析

利用1960~2012年降水气象资料,计算了武陵山区各个季节的降水距平指数,在此基础上,分季节分析了该区域干旱发生时空分布特点,其中,在春季和夏季,轻旱和中旱发生频率略高,中北部地区较重;在秋季和冬季,各个等级干旱均有较高频率分布,且不同等级分布格局有所不同。通过构建旱灾危害度指数,分析了各个季节及年度旱灾危险性空间分布特点,认为春旱和夏旱北部风险度较高,秋旱中东部风险度较高,冬旱在东北部及中部局部风险较高,年尺度旱灾风险区域整体较低。在此基础上,通过将各季节旱灾危害度与地形要素进行关系分析,认为春旱和夏旱与海拔相关度较高,各季节干旱与坡度及地形起伏度相关性不显著。本研究结论对武陵山区合理规划建设,发展农业生产具有一定参考意义。