Temporal–spatial variability of atmospheric and hydrological natural disasters during recent 500 years in Inner Mongolia, China

Inner Mongolia, located in the northern China, is a natural disaster-prone region. This study is dedicated to making a comprehensive and quantitative analysis of the temporal–spatial patterns and its scale dependence of atmospheric and hydrological natural disaster frequency and intensity and its trend and correlation among them at 10-, 50- and 100-year cycle during recent 500 years by spatial statistics and geographical information system. The results indicated that the occurrence frequency and intensity were generally increased during last 500 years, with accelerating rate in recent one century, more obviously for drought and flood. The parts in southwest, middle and northeast region have suffered severe disaster pressure with an evident ascending trend. The scale dependence in temporal and spatial patterns of atmospheric and hydrological natural disasters was found. Totally, the disasters showed a clustered distribution during recent 500 years while snow dispersed during 1516–1615 and 1816–1915. By M–K test, the intensity of drought at 10-year cycle and flood at 50-year cycle, the frequency of hail and flood at 50-year cycle have significant increasing trend. Flood and hail mainly appeared in the middle, north and northeast parts, while wind appeared in most counties and snow scattered in the region. It is also found a close association among various disasters in either occurrence or intensity. Snow, hail and wind have significant opportunities to simultaneously happen at 10- and 50-year cycles. Hail has more chances to occur with flood, snow at all cycles, with drought at 10- and 100-year cycle, and wind at 10- and 50-year cycle. This study is anticipated to support the mitigation of natural disasters and to improve the management practices of environment system in a large-scale region.