Water and heat flux characteristics and driving factors of dune ecosystem in Horqin Sandy Land
In this study,we investigated the surface energy fluxes in a typical dune ecosystem of the Horqin Sandy Land using an Eddy Covariance(EC)system for continuous monitoring from 2013 to 2022.The Ordinary Least Squares linear regression(OLS)and the Energy Balance Ratio(EBR)were applied to evaluate the energy balance closure,including monitoring of the diurnal,seasonal,and interannual variations in energy flux during the growing season(April to October),calculating Bowen ratio(β)and the energy balance,and assessing influences of environmental factors on the variations in latent heat flux(LE),sensible heat flux(H),and soil heat flux(G).The results reveal that the multi-year average annual net radiation(Rg)was observed at 1592.8MJ/m2,contributed by H,LE,and G as 614.0,636.2,and 117.8MJ/m2,respectively.The dominant component of the annual energy budget was found to be latent heat flux,constituting 40％of the total energy.The diurnal dynamic curve of β exhibited a unimodal pattern with relatively mild fluctuations.The multi-year annual mean EBR ranged from 0.75 to 0.90,indicating a 13％residual in energy balance closure.The study demonstrates that vapor pressure deficit(VPD)was the primary factor influencing energy flux,followed by air temperature(Ta)and soil temperature(Ts),all showing significant positive correlations with energy flux.Additionally,the impact of vegetation on energy flux was observed to be a positive correlation between LE and leaf area index(LAI),while H exhibited a negative relationship with LAI.
万方数据
维普
