农业旱灾及其指标系统研究

广泛查阅前人工作,发现国内外研究农业旱灾采用的各种各样定性或定量的指标,其侧重点各有不同,这使农业旱灾的时空特征在一定程度上依赖于所用的指标,针对同一问题可能出现不一致的结论.本文依据自然灾害系统理论,对农业干旱和旱灾进行了系统性分析,指出农业旱灾具有时间尺度和空间尺度特征,依据前人提出农业旱灾具有的"三维"特征的说法,总结出农业旱灾可被看作是一个"五维"系统,即对于任何一次农业旱灾都可以认为是在特定的孕灾环境下,由于一段时间内降水量相对缺少导致农作物无法正常生长,产量减少.这种现象具有空间上的分布性,对国内外研究农业旱灾所采用的各种各样定性、定量的指标,在不同的时闻、空间尺度上,从致灾因子、孕灾环境以及承灾体或灾损角度对农业旱灾指标进行系统分类,以期为在不同时空尺度下选择适当的指标进行农业旱灾的深入研究提供依据.

Systematic study on agricultural drought disaster and its indices

It is found that the spatial-temporal features of agricultural drought disaster is dependent on the indices applied to some degree,because of so many of all kinds of indices,which put different emphasis on quality and quantity,so for a special agricultural drought disaster,it can be drawn in different conclusions because of different indices applied.According to system theory of natural disaster,agricultural drought disaster is systematically analyzed,and the temporal and spatial characteristics of which are put forward,so agricultural drought disaster can be seen as a 5-dimension system,that is,any one time agricultural drought disaster can be seen as the decrease of grain yield caused by the deficit or shortage of precipitation in a special inducing hazard environment during a time period,and which is spatially various.According to systematic characteristics of agricultural drought disaster,the indices for agricultural drought disaster can be classified into three types from the perspective of formative factor,environment of breeding disasters and disaster-affected bodies separately at different time and space scale.