基于MODIS数据的辽西北地区玉米干旱脆弱性评价研究

THE STUDY OF VULNERABILITY ASSESSMENT ON MAIZE DROUGHT IN THE NORTHWEST OF LIAONING PROVINCE BASED ON MODIS

关键词:  MODIS影像 玉米干旱 脆弱性 植被状态指数 温度条件指数

Key words:  MODIS image  maize drought  vulnerability  Vegetation Condition Index  Temperature Condition Index

摘要:

传统区域作物脆弱性的研究主要基于气象资料、作物生长观测资料和社会经济统计资料，忽略了作物对极端事件的反应在时空分布上的差异性。众多研究表明，植被指数能够表征水分胁迫下的植被特征，在对旱情的表达上比常规的间接方法更为直接，监测精度更高。研究以辽西北地区2006年玉米干旱为例，基于MODIS数据计算植被状态指数VCI和温度条件指数TCI，根据二者在旱情表达上不同的侧重和研究目的，确定模型参数，构建辽西北地区玉米干旱脆弱性模型，计算玉米干旱脆弱性，并将玉米干旱脆弱性划分为4级，借助GIS技术绘制辽西北地区玉米各生育阶段干旱脆弱性的空间分布图。结果表明，随着时间的推移，辽西北地区玉米干旱脆弱性空间分布也在发生着变化。研究实现了玉米干旱脆弱性在时间变化和空间分布上的差异变化描述，为区域因地制宜地制定防灾减灾规划提供科学依据。

Abstract:

The traditional studies on crop vulnerability were based on meteorological data, observational data and social and economic statistics, which overlooked the differences of spatial and temporal distribution because of the crop reaction to extremely event. Many studies indicated that vegetation index can directly express crop drought condition, which was more precision than the traditional method. Taking maize drought in 2006 in the northwest of Liaoning province as an example, this paper calculated the Vegetation Condition Index and Temperature Condition Index based on MODIS data. The model of vulnerability of maize drought in the study area was established and the model parameters were determined based on the different expression on drought between VCI and TCI. The vulnerability indexes were calculated and divided into 4 grades. The spatial distribution maps of vulnerability at different growth stages were drawn using GIS. It showed that the spatial and temporal vulnerability distribution of maize at each growth stage changed over time. The results can be used to describe maize drought vulnerability differences in spatial distribution and temporal variation, and provide a scientific basis for making drought defense strategies based on local conditions.