Quantitative analysis of causal relationship between meteorological factors and evapotranspiration in the upstream basin of Dong Nai river

Abstract

Evapotranspiration (ET) in the basin results from the complex interaction between meteorological factors and surface conditions. This study quantitatively analyzes the aforementioned causal relationships spatially and temporally using the Convergent Cross Mapping (CCM) method. Meteorological data series from 1984 to 2023 at four meteorological stations in the Upstream basin of Dong Nai River were statistically processed and analyzed using the CCM method. The rEDM package in R software was utilized for calculations. The results indicate that in this basin, solar radiation n ( ρ = 0,3 2 ) has the strongest causal relationship with ET and is positively correlated ( ???? ???? = 0 , 26 ). Next, relative humidity RH has a negative correlation and is the second strongest causal relationship ( ???? = 0 , 23 , ???? ???? = − 0 , 38 ). Wind speed u ( ρ = 0, 04 ) has a causal relationship but no correlation with ET ( ???? ???? = − 0 , 03 ). Precipitation R ( ρ = 0,0 9 ) has no causal relationship with ET. Causal analysis among meteorological variables sh ows an indirect causal relationship between n and T with ET through RH. Specifically, n is positively correlated and has a strong causal relationship with T ( ???? = 0 , 30 , ???? ???? = 0 , 31 ), T is negatively correlated and has a strong causal relationship with RH ( ???? = 0 , 21 , ???? ???? = − 0 , 34 ), and RH is negatively correlated with ET ( ???? = 0 , 23 , ???? ???? = − 0 , 38 ). The weak relationship between u and RH ( ???? = 0 , 03 , ???? ???? = 0 , 03 ) indicates that RH has no association with u. Therefore, when calculating ET using forecasting models, attention sho uld be paid to the data of n, T, and RH for this basin.