基于实际蒸散构建的干旱指数在黄淮海地区的适用性

基于NOAH陆面模式模拟的实际蒸散产品,分析了2002—2010年黄淮海地区实际蒸散的时空分布特征.同时,结合MOD17潜在蒸散数据和MOD13 NDVI构建了2002—2010年的农业干旱指数——干旱敏感性指数(DSI),并以2002年1—12月为例,利用帕默尔干旱指数(PDSI)、冬小麦减产率以及实际旱情资料,分析了DSI在该地区干旱监测的适用性.结果表明: 黄淮海地区年均实际蒸散从西北向东南递增,最高值出现在研究区域东南部(800~900 mm),最低值出现在西北部(<300 mm);DSI、PDSI两种干旱指数的年际变化呈正相关(R²=0.61)和变化趋势的一致性,均在2002年达到最低(-0.61和-1.33),2003年最高(0.81和0.92),DSI与冬小麦减产率的相关性(R²=0.43)明显优于PDSI(R²=0.06),且表征干旱的空间分辨率较高,对区域农业干旱程度的判断和旱情的指示比较可靠.

Applicability of established drought index in Huang-Huai-Hai region based on actual evapotranspiration.

Based on the modeled products of actual evapotranspiration with NOAH land surface model, the temporal and spatial variations of actual evapotranspiration were analyzed for the Huang-Huai-Hai region in 2002-2010. In the meantime, the agricultural drought index, namely, drought severity index (DSI) was constructed, incorporated with products of MOD17 potential evapotranspiration and MOD13 NDVI. Furthermore, the applicability of established DSI in this region in the whole year of 2002 was investigated based on the Palmer drought severity index (PDSI), the yield reduction rate of winter wheat, and drought severity data. The results showed that the annual average actual evapotranspiration within the survey region increased from the northwest to the southeast, with the maximum of 800-900 mm in the southeast and the minimum less than 300 mm in the northwest. The DSI and PDSI had positive correlation (R²=0.61) and high concordance in change trend. They all got the low point (-0.61 and -1.33) in 2002 and reached the peak (0.81 and 0.92) in 2003. The correlation between DSI and yield reduction rate of winter wheat (R²=0.43) was more significant than that between PDSI and yield reduction rate of winter wheat (R²=0.06). So, the DSI reflected a high spatial resolution of drought pattern and could reflect the region agricultural drought severity and intensity more accurately.