华北平原干旱事件特征及农业用地暴露度演变分析

摘要

根据1961-2014年华北平原52个气象观测站月降水数据和区域气候模式COSMO-CLM（CCLM）输出的逐月降水预估数据，利用标准化降水指数，结合“强度-面积-持续时间”（Intensity-Area-Duration, IAD）方法，研究了华北平原过去（1961-2014年）和未来（2016-2050年）3种排放情景(RCP2.6、4.5、8.5）下，不同持续时间的区域最强干旱事件的强度-面积特征及其时空分布规律。同时，基于2000年的土地利用数据，分析了2016-2050年华北平原农业用地暴露度的演变。研究表明：（1）1961-2014年，华北平原干旱中心在空间上呈由南向北迁移的趋势。（2）相比基准期（1961-2005年），过去45a未遇的干旱事件在2016-2050年RCP3种情景下均有可能发生；RCP2.6情景下发生频率最高。（3）2016-2050年，RCP2.6和RCP 4.5情景下，华北平原农业用地干旱暴露度（即暴露面积）呈增大趋势，RCP4.5情景下干旱暴露面积增加的速率更大，RCP8.5情景下则与之相反，呈减小趋势。3种情景下暴露度峰值分别出现在2040s后期，2040s前期及2020s中期。%s: Based on the observed monthly precipitation data of 52 meteorological stations for 1961-2014 and the projected data of regional climate model COSMO-CLM (CCLM), the standardized precipitation index (SPI) and the Intensity-Area-Duration method (IAD method) were used to analyze the characteristics and spatial-temporal distribution of the drought events in the past (1961-2014) and future (2016-2050) under RCP scenarios(RCP2.6, 4.5,8.5 ). And the evolution of agricultural land exposure to these drought events in 2016-2050 was estimated by applying the land use data in 2000. Results showed that: (1) from 1961 to 2014, the spatial distribution of drought center migrated from south to north in the North China Plain. (2)The unprecedented drought events are projected to occur in all three RCP scenarios in 2016-2050,and probably happens more frequently in RCP2.6 than other scenarios. (3) Under RCP2.6 and 4.5 scenarios, the exposure of agricultural land to drought is expected to raise, and that of RCP4.5 scenario increases comparatively faster. While, the trend of agriculture land exposure might decrease under RCP8.5 scenario for 2016-2050. The peak value of agricultural exposure under three RCP scenarios will occur in the late 2040s, the early 2040s, and the mid-2020s, respectively.