气象与农业干旱指数研究进展

Advance in the Study on Meteorological and Agricultural Drought Indices

干旱是世界上最常见也是危害最大的自然灾害,是制约我国农业生产的主要自然因素。在监测与评估干旱对农业生产造成的影响工作中,选取合理的干旱指数显得尤为重要。干旱影响范围很广,波及到农业、生态、林业、水文等行业。不同行业有不同的干旱指数,而气象干旱指数是其他行业干旱指数的基础。气象干旱指数分早期干旱指数,Palmer干旱指数,标准化的干旱指数,综合气象干旱指数。农业干旱指数分为土壤水分指数类、作物生理生态指数类和卫星遥感干旱指数。气象干旱指数关注的是水分偏离常态的程度,而农业干旱更强调土壤水分满足农田蒸散的程度。关注点的差异限制了气象干旱指数在农业干旱监测评估中的应用效果。理想的农业干旱指数应具备以下三个特点:良好的时空分辨率、反映农田水分平衡机理和空间上相对稳定的阈值。结合气象和遥感数据,针对降水与农田蒸散需水量之间的矛盾设计干旱指数,是满足干旱监测对时空分辨率要求,准确反映干旱对作物胁迫及危害的可行途径。

Drought is a most common natural disaster,and it is also the main natural factor restricting China’s agricultural production.In monitoring and assessing the impact of drought on agricultural production,it is very important to select a reasonable drought index.Drought affects a wide range of industries,including agriculture,ecology,forestry,and water conservancy.Different industries have different drought indices,and the meteorological drought index is the basis of drought indices for other industries.The meteorological drought index is divided into four categories:early drought index,Palmer drought index,standardized drought index,and comprehensive meteorological drought.The agricultural drought index is divided into soil water index,crop physiological index and satellite remote sensing drought index.The meteorological drought index focuses on degree of water deviation from the normal state,while the agricultural drought index emphasizes more on the degree of soil moisture to satisfy the farmland evapotranspiration.The difference in concerns limits the application of the meteorological drought index in agriculture drought monitoring and assessment.The ideal agricultural drought index should have the following three characteristics:good spatial and temporal resolution,reaction farmland water balance mechanism and relatively stable threshold in space.Based on meteorological and remote sensing data,designing drought index by contradiction between precipitation and evapotranspiration water demand in farmland can meet the requirements of time-space resolution of drought monitoring,and has a good performance in indicating water stress intensity on crops.