条件植被指数在海河流域干旱评价中的应用

鉴于海河流域干旱问题突出,根据2001~2013年MODIS的NNDVI数据构建了条件植被指标(VVCI)对海河流域进行月尺度干旱评价,并采用标准化降水指数(SSPI)和河北省农业干旱受灾面积(AADAA)资料与其对比验证,在此基础上,进一步分析了海河流域近13年干旱特征。结果表明,VVCI指标较传统的SSPI指标在海河流域具有更好的适用性;海河流域整体干旱呈减缓趋势,而平原区白洋淀平原和子牙河平原的干旱均呈加剧趋势;3~6月和10~12月是海河流域干旱易发期,表明海河流域冬小麦受干旱影响的风险较大,尤其是春旱问题突出。

Application of Vegetation Condition Index in Drought Estimation of Haihe Basin

Haihe basin is a typical drought-prone area of China. Based on the monthly NNDVI data deriving from MODIS during 2001-2013, the vegetation condition index VVCI have been calculated to estimate the drought in Haihe basin. Then the VVCI were compared with the standard precipitation index SSPI and agriculture drought affected area AADAA in Hebei Province. Furthermore, the recent 13 years drought feature of Haihe basin was analyzed according to the VVCI. The results show that the VVCI performs better than SSPI in describing the drought condition of Haihe basin. The drought appears a decreasing trend in Haihe basin, while the drought in Baiyangdian plain and Ziyahe basin plain appear an increasing trend. Additionally, the monthly drought characteristics of Haihe basin indicates that the high incidence of drought focus on March to June and October to December, which shows that drought risk on winter wheat will be serious, especially in spring.