Abstract
Drought refers to a meteorological disaster that causes insufficient soil moisture and damage to crop water balance due to long-term lack of precipitation. With the increasing shortage of water resources, drought has become one of the hot issues of global concern. The standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) can effectively reflect the changes in drought characteristics of different geomorphologies in Sichuan on time and space scales, to explore the difference in drought characteristics between different physiognomy types in Sichuan Province, We calculated the SPI and SPEI values based on the data of 44 meteorological stations in Sichuan Province from 1961 to 2019 and used Mann–Kendall trend test and multivariable linear regression method (MLR) to quantify the significance of the drought characteristic trends at different time and space scales. The results as follow: (1) The SPEI drought trend in plain and hilly regions was greater than that in plateau and mountain regions on all time scales (− 0.039 year−1 for 1-month in hilly, − 0.035 year−1 for 1-month in plain, − 0.14 year−1 for 1-month in plateau, − 0.026 year−1 for 1-month in mountain) and the magnitude of trend of eastern (− 4.4 to 0.1 year−1) was lager than western (− 2.1 to 2.7 year−1), means that the drought trends transfer from northwest to east. (2) The drought intensity in the western region gradually increased (0.54–1.05) and drought events mainly occurred in the southwest plateau and central mountainous regions (24–47 times), means that drought meteorological hotspots were mainly concentrated in the Sichuan basin. (3) The MLR indicated altitude (H) is not the main influencing factor that causes the spatial unevenness of precipitation in Sichuan Province, but altitude (H), temperature (T), longitude (Lo) and latitude (La) can co-determined the precipitation. The results of this study are instructive and practical for drought assessment, risk management and application decision-making in Sichuan Province, and have guiding significance for agricultural disaster prevention, mitigation and agricultural irrigation in Sichuan Province.
Highlights
Drought has been one of the major natural disasters faced by human beings since ancient times
The main research purpose in the article as follows: (1) Calculate standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) at different time scales based on precipitation and evapotranspiration, and use Mann–Kendall test (M–K trend test) to determine the drought trend of different geographical features, (2) calculate drought intensity, drought frequency and precipitation trend coefficient to analyze the spatiotemporal distributions of drought hotspots in Sichuan Province, (3) analyze the influencing factors leading to the difference of drought precipitation trend among different topography by using multivariable linear regression method (MLR)
Wu based on the principle of vegetation water supply index (VWSI) test the Sichuan drought spatial distribution and in-site time series analysis, the results show that drought meteorological hotspots are mainly concentrated in the Sichuan basin, because this area is surrounded by mountains, which is difficult for the continental monsoon to release after the basin sinks, causing this area to become a hotspot with frequent droughts[19]
Summary
Drought has been one of the major natural disasters faced by human beings since ancient times. Mckee[10] replaces PDSI with standardized precipitation index (SPI), which has well applicability in time, space and rainfall probability distribution, and can detect the characteristics of drought activity over a wide area on different time scales, the SPI determined that precipitation is the main factor affecting drought intensity and duration[11]. The main research purpose in the article as follows: (1) Calculate SPI and SPEI at different time scales based on precipitation and evapotranspiration, and use Mann–Kendall test (M–K trend test) to determine the drought trend of different geographical features, (2) calculate drought intensity, drought frequency and precipitation trend coefficient to analyze the spatiotemporal distributions of drought hotspots in Sichuan Province, (3) analyze the influencing factors leading to the difference of drought precipitation trend among different topography by using multivariable linear regression method (MLR). The results may be a reliable reference for the government to improve the specificity of drought prevention areas when considering ecological protection in the future
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