Surface Temperature Simluation And Driving Mechanism Analysis Of Wuding River Basin Based On CLM

Land surface temperature(LST),as one of the important variables in the land atmosphere coupling process,its spatiotemporal distribution is influenced by climate change and human activities.By using the CLM(Community Land Model)model to simulate the surface temperature of the Wuding River Basin,the spatiotemporal distribution pattern of surface temperature from 2005 to 2021 was obtained.Based on the simulated data of surface temperature,meteorological factors,land use types,leaf area index(LAI)and other types,the driving mechanism of surface temperature elements in the Wuding River Basin was explored.The main research results are as follows:(1)The main meteorological elements of LST in the Wuding River Basin are solar radiation and temperature.From the results of uncertain analysis,it can be seen that the solar radiation and temperature elements in driving data such as ERA5,CMFD,and GSWP3 have good applicability in the Wuding River region and can be used to drive the CLM model to simulate LST,Taking into account the uncertainty analysis of atmospheric forcing data,the evaluation of LST simulation effectiveness,and the availability of the data itself,ERA5 was ultimately determined as the optimal atmospheric driving dataset.(2)The year of LST mutation in the Wuding River Basin is 2009.During the two periods before and after the mutation,the LST in the Wuding River Basin showed a cooling trend,but overall from 2005 to 2021,the LST in the Wuding River Basin showed an increasing trend.LST showed an upward trend in spring,autumn,and winter,with only a downward trend in summer.In terms of spatial distribution,LST shows high in the southeast and low in the northwest.(3)The LAI in the Wuding River Basin mainly shows a significant growth trend.The spatial characteristics show a low northwest and high southeast.The solar radiation mainly shows a downward trend,while the temperature shows an increasing trend.The temperature gradually decreases from southeast to northwest,and the spatial distribution characteristics of solar radiation gradually decrease from south to north.Between 2005 and 2020,the area of construction land,grassland,and forest land increased,while the area of unused land and arable land decreased.The main types of human activities in the watershed were grass planting and reclamation,with restoration human activities accounting for 56.93%.(4)After improving vegetation conditions,the LST in the Wuding River Basin mainly manifests as cooling.Δ LST and Δ LAI shows a trend of increasing first and then decreasing at the seasonal scale.Solar radiation and temperature are mainly positively correlated with LST,with a higher correlation with temperature before the sudden change year;After the mutation year,the main meteorological factor affecting LST is solar radiation.Human activities have a cooling effect on the Wuding River Basin,and after a sudden change in year,the cooling effect of human activities weakens.(5)The LST changes in the Wuding River Basin are mainly regulated by human activities;After the mutation,the driving force of climate change on LST change has increased,with 37.14%of the region transforming into a joint impact of climate change and human activities.Based on the types of human activities in the region and the LST simulation results under different conditions,the cooling trend of LST changes in the Wuding River Basin before and after the mutation year is closely related to restorative human activities.