The 2012 Flash Drought Threatened US Midwest Agroecosystems
The 2012 Flash Drought Threatened US Midwest Agroecosystems
复制标题
2012 年突发干旱威胁美国中西部农业生态系统
DOI：
10.1007/s11769-019-1066-7
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发表时间：
2019-10-01
影响因子：
3.4
通讯作者：
Zhao, Deyu
中科院分区：
文献类型：
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作者：
Jin, Cui;Luo, Xue;Zhao, Deyu
2012年夏天，全球生产力最高的农业地区美国中西部遭遇了近百年来最严重、最广泛的干旱。 2012年的干旱以“骤旱”为特征，5月份开始出现，随后迅速加剧，7月中旬达到顶峰。类似地，76%的农作物区和60%的草原和牧区已处于中度至重度干旱条件下。本研究使用多种证据，即原位 AmeriFlux 测量、空间卫星观测和比例生态系统模型，对 2012 年突发干旱对美国中西部植被绿度和光合作用碳吸收的影响进行独立和补充分析。三个数据集一致表明：1）与 2010-2014 年其他年份相比，2012 年所有生物群落的物候活动提前了 1-2 周； 2）干旱对农业生态系统（农作物和草地）的影响比对森林的影响更为严重； 3）从6月份开始，农作物和草地的生长受到抑制，植被指数、太阳荧光（SIF）和总初级生产力（GPP）显着下降，直到生长季末才恢复。模型结果显示，2012年地区GPP总量是2010-2014年期间最低的（1.76 Pg C/年），与其他年份平均水平相比下降了63 Tg C。农业生态系统占区域 GPP 同化的 84%，受到 2012 年干旱的影响最大，玉米、大豆、耕地和草地的 GPP 总量分别下降了 9%、7%、6% 和 29%。预计未来干旱的频率和严重程度将会增加。结果表明研究突发干旱对植被生产力和陆地碳循环影响的重要性。
In the summer of 2012, the US Midwest, the most productive agricultural region in the world, experienced the most intense and widespread drought on record for the past hundred years. The 2012 drought, characterized as 'flash drought', developed in May with a rapid intensification afterwards, and peaked in mid-July. similar to 76% of crop region and 60% of grassland and pasture regions have been under moderate to severe dry conditions. This study used multiple lines of evidences, i.e., in-situ AmeriFlux measurements, spatial satellite observations, and scaled ecosystem modeling, to provide independent and complementary analysis on the impact of 2012 flash drought on the US Midwest vegetation greenness and photosynthesis carbon uptake. Three datasets consistently showed that 1) phenological activities of all biomes advanced 1-2 weeks earlier in 2012 compared to the other years of 2010-2014; 2) the drought had a more severe impact on agroecosystems (crop and grassland) than on forests; 3) the growth of crop and grassland was suppressed from June with significant reduction of vegetation index, sun-induced fluorescence (SIF) and gross primary production (GPP), and did not recover until the end of growing season. The modeling results showed that regional total GPP in 2012 was the lowest (1.76 Pg C/yr) during 2010-2014, and decreased by 63 Tg C compared with the other-year mean. Agroecosystems, accounting for 84% of regional GPP assimilation, were the most impacted by 2012 drought with total GPP reduction of 9%, 7%, 6%, and 29% for maize, soybean, cropland, and grassland, respectively. The frequency and severity of droughts have been predicted to increase in future. The results imply the importance to investigate the influences of flash droughts on vegetation productivity and terrestrial carbon cycling.