我国农业水旱灾害的时间分布及重灾年景趋势预测

分析了我国 1970～ 1999年农业水旱灾害的时间分布特征。分析结果表明 :在研究时段内 ,我国农业自然灾害总体上呈增长态势。该时段可划分为两个明显的阶段 :80年代中期以前 ,总灾、水灾及旱灾对农业生产的危害较轻 ;80年代中期之后 ,呈现出影响范围广、损失增大的趋势 ,重灾年份明显增加。旱灾和水灾是威胁我国农业生产最为严重的自然灾害 ,尤以旱灾为甚。我国农业遭受旱灾威胁的范围多年基本不变 ,而旱灾受灾率波动明显 ,成灾率逐年增长 ,这与近几年农田水利设施建设缓慢、灌溉能力降低有关 ;水灾受灾率和成灾率具有特别显著的同步特点 ,表明水灾致灾能力强 ,一旦发生 ,极易成灾 ,水灾危害加剧与防洪、抗洪能力低下及生态环境恶化有关。各灾种的受灾率和成灾率呈正相关关系 ,表明我国农业生产系统的抗灾能力总体上较弱。　　本文还用灰色系统理论的建模方法 ,建立了农业总受灾率 -总成灾率、水灾受灾率 -成灾率、旱灾受灾率 -成灾率的重灾年景灰色灾变GM(1,1)预测模型 ,对未来 10年我国农业灾害趋势进行了预测分析。灰色预测结果表明 ,2 0 10年之前 ,除 2 0 0 3,2 0 0 6年水旱灾害危害较小外 ,其它年份均为灾情严重年份 ,其受灾率和成灾率均高于近 30年的平均水平。其中 ,2 0 0 4 ,2 0 0 7年将为水灾重

Temporal distribution and trend prediction of agricultural flood and drought disasters in China

This article analyzes the temporal distribution characters of agricultural flood and drought disasters during the period from 1970 to 1999 in China. It can be seen from the analysis that agricultural natural disasters increased in the research period. Two phases can be evidently indicated: total disasters and flood and drought had lower harm to agriculture before the middle of 1980s; great disaster, influenced area and losses increased evidently after the middle of 1980s. Drought and flood were the more harmful natural disasters to agriculture and drought was the most in particular. The area suffered from drought were not changed in general. The ratio of drought-affected area fluctuated evidently and the ratio of disaster-suffering area increased year after year. This trend may relate to the slow development of farmland irrigation facilities. The ratio of flood-affected area was synchronous with the ratio of the disaster-suffering area. It shows that flood can easily causes disaster once it happens. The increase of harmfulness caused by flood may attribute to the lower capacity of protection and the deterioration of eco-environment. The ratio of suffering area and the ratio of affected area for all kinds disasters are positive correlative. This indicates the resistance capacity of agriculture system in China is faintish in general. Based upon the gray system method, models are established for predicting the ratios of affected area to suffering area in agricultural total disaster, flood and drought, and their trends in the future ten years. Gray modeling results indicate that heavy disasters will occur in all the ten years except for 2003 and 2006. The ratios of disaster affected area and of disaster suffering area will be over the average levels in the past 30 years. Great flood will happen in 2004 and 2007, and drought and flood will occur simultaneously in 2002 and 2009.