Identification of Regional Drought Processes in North China Using MCI Analysis

Abstract

Comprehensive identification of drought events is of great significance for monitoring and evaluating drought processes. Based on the date of daily precipitation, temperature and drought-affected area of 403 meteorological stations in North China from 1960 to 2019, the Comprehensive Drought Process Intensity Index (CDPII) has been developed by using the Meteorological-drought Composite Index (MCI) and regional drought process identification method, as well as the EIDR theory method. The regional drought processes in the past 60 years in North China, including Beijing, Tianjin, Hebei, Shanxi and Middle Inner Mongolia, were analyzed and identified. The result shows that the distribution characteristic of droughts with different intensities is as follows: The number of days of all annual-average mild droughts, moderate droughts and severe droughts was highest in Tianjin and that of extreme droughts was highest in Shanxi. The number of days of mild droughts was highest in May and lowest in January. The number of days of moderate droughts was highest in June. The number of days with mild and moderate drought showed an overall increasing trend, while the number of days with severe drought and above showed an overall decreasing trend (through a 95% significance test). The number of drought days was the highest in the 1990s. The annual frequency of drought is between 66.7% and 86.7%; the drought frequency in Hebei is the highest at 86.7%, followed by Beijing at 80%. There were 75 regional drought processes in North China from 1960 to 2019, and the correlation coefficient between process intensity and the drought-affected area was 0.55, which passed the 99% significance test. The comprehensive intensity of drought process from 27 April to 1 September 1972 was the strongest. From 18 May to 31 October 1965, the drought lasted 167 days. The overall drought intensity had a slight weakening trend in the past 60 years. A total of 75 regional drought processes occurred in North China, and the process intensity showed a trend of wavy decline with a determination coefficient (R2) of 0.079 (95% significance test). Overall, the regional drought process identification method and strength assessment result tally with the drought disaster, which can better identify the regional drought process. Furthermore, including the last days, the average intensity, average scope comprehensive strength, there are many angles to monitor and evaluate the drought and drought process. These provide a reference for drought control and decision-making.

Multidimensional identification of single and regional meteorological drought considering flash‐season synthesis employed daily standardized effective precipitation and drought index in Guangxi, China

“…(2012) proposed an objective identification method for regional extreme events (OITREE), which reasonably “strings” the daily impact range into a string to form a complete regional event, that is, the “sugar gourd string” model. At present, this method has been widely used in the study of regional extreme events such as drought, extreme heavy precipitation in China and has achieved good results (Li et al ., 2014; Wu et al ., 2019; Cai et al ., 2021). Zhang et al .…”

“…For this purpose, Ren et al (2012) proposed an objective identification method for regional extreme events (OITREE), which reasonably "strings" the daily impact range into a string to form a complete regional event, that is, the "sugar gourd string" model. At present, this method has been widely used in the study of regional extreme events such as drought, extreme heavy precipitation in China and has achieved good results (Li et al, 2014;Wu et al, 2019;Cai et al, 2021). Zhang et al (2021) improved the OITREE method and then carried out research on regional drought process identification and assessment techniques in the middle and lower reaches of the Yangtze River.…”