Abstract:
Background To study the spatial and temporal distribution characteristics of potential evapotranspiration (PET) and drying index (IA) in Xilingol League and to understand the drought situation in this area are of great significance for further study of vegetation status, environmental change and agricultural water resources management in this area.
Methods Based on the meteorological data of 11 weather stations in and around the study area from 1957 to 2016, the PET and IA values were obtained using Penman-Montes model (P-M model) and IA formulas. Three mutation detection methods, radial basis function interpolation method and partial correlation analysis were used to explore the temporal and spatial characteristics of PET and IA and their influencing factors.
Results From 1957 to 2016, the average PET was 875.82 mm and IA was 0.615 6, which showed an increasing trend; the distribution of P ET was mainly concentrated in summer, accounting for 46.28%, the smallest in winter, accounting for only 4.15%, the largest in spring, the driest in summer, the smallest in relative humidity. Both PET and IA showed an increasing trend from northeast to southwest; the mutation of PET occurred in 1984 and 1998, IA abrupt change occurred in 1998 and 2001; PET and IA were the most sensitive to wind speed.
Conclusions The degree of drought in the study area increased from 1957 to 2016. Statistics for many years showed that the drought was the most severe in spring, and the degree of drought in spatial distribution increased from northeast to southwest.
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