Spatiotemporal variations in damages to cropland from agrometeorological disasters in mainland China during 1978-2018

摘要

Drought, flood, hail, low temperature, and frost (LTF) are the main agrometeorological disasters (AMDs) in China; however, comprehensive and quantitative studies on cropland damage induced by AMDs across the whole country in terms of long-term trends are still lacking and urgently needed. Based on historical statistical data from yearbooks and bulletins, the overall characteristics of cropland damage by AMDs during 1978-2018 were analyzed using a pre-whitening procedure and a Mann-Kendall trend test at yearly and provincial scales in China. The results showed that drought was the most severe, with an average covered area of 22.2 million ha and an affected area of 11.2 million ha every year during 1978-2018, followed by flood, hail, and LTF. A decreasing trend was observed in covered area and affected area by drought, flood, and hail, while only LTF showed an increasing trend. On provincial scale, more than 70% of the covered area by AMDs was induced by drought and flood in most provincial districts. In all provincial districts of northern China, more than 50% of the covered area was induced by drought. In most provincial districts of southern China, more than 40% of the covered area was induced by flood. Hail disasters were prominent in Xinjiang, with significant increasing trends among all parameters. Compared with the other three AMDs, LTF covered and affected the smallest cropland area, but significant increasing trends were observed in the northwest and middle parts of China. The results of this study systematically display the characteristics of damage to cropland by four main AMDs, which are critical and necessary for disaster risk reduction and adaptive strategy development.