基于降水Z指数的朝鲜降水及旱涝时空特征

利用TRMM（Tropical Rainfall Measuring Mission,TRMM）3B43月降水数据,并结合降水Z指数,研究朝鲜1998—2018年的降水和旱涝时空格局。结果表明：TRMM与站点观测降水数据有显著的相关性。朝鲜降水季节性特征明显,57.29%的降水集中在夏季,空间上自东北部沿海岸线向东南递增。朝鲜的区域综合旱涝等级基本处于正常状态,偏旱和偏涝发生的频率最高,其次是大旱和大涝,极旱和极涝发生的频率最低,夏季和冬季干旱发生最为频繁,而洪涝在秋季频发。朝鲜北部发生旱涝事件的频率明显高于南部,咸镜山脉和盖马高原是旱涝的多发地区,温泉平原则最不易受到旱涝影响。春季、夏季和秋季均呈现洪涝强度增强的趋势。夏季洪涝强度加剧的趋势明显,中北部地区通过95%的显著性检验。

Spatiotemporal patterns of precipitation and drought and flood using Z-index in Democratic People's Republic of Korea

Drought and flood are the main agrometeorological disasters in the Democratic People's Republic of Korea (DPRK), which have great influences on the growth of the crops and directly affect grain yield. The level of agricultural production is low because of insufficient investment and poor irrigation installation. Drought and flood are prone to a reduction in grain yield in DPRK. The food security issue in DPRK is not only related to this country's domestic stability but also related to the geo-security in Northeast Asia. Therefore, understanding the spatial and temporal patterns of drought and flood is very important for preventing disasters in this country. In this study, the Tropical Rainfall Measuring Mission (TRMM) 3B43 time series dataset was used to reveal the spatial and temporal patterns of drought and flood in DPRK from 1998 to 2018. The drought and flood levels were developed by a Z-index. In addition, the trend of Z-index is tested by the Mann-Kendall (M-K) method. The result shows that the precipitation in the study area has an obvious seasonal pattern, with more than 57.29% of the rainfall concentrated in summer, and only 6.90% in winter. The precipitation in spring is slightly higher than that in autumn. Both interannual and seasonal precipitation show increasing trends during the study period. The spatial pattern of precipitation increases from the northeast to the southeast along the coastline. Generally, the regional comprehensive drought and flood levels in DPRK are normal at the national scale. Moderate drought and flood levels occur most frequently, followed by severe drought and flood, and the frequency of extreme drought and flood eventd is the lowest. The floods frequently occur in autumn, and droughts frequently occur in summer and winter. The frequency of drought and flood events appear in the north of DPRK, particularly in Hamgyeong Mountains and the Gaema Plateau. Flood intensity shows an increasing trend in spring, summer, and autumn, while drought and flood level tended to be normal in winter. The central and northern regions passed the significance of 95%. It is expected that the trend of drought and flood in DPRK will be consistent in future. The results of the study provide a unique insight for understanding the agricultural production in DPRK.