Spatio-temporal evolution of surface heat flux during new urbanization in mountainous region: A case study of Yuelai New City

In order to explore the spatio-temporal evolution law of surface heat flux during the urbanization process in new mountainous development city, the spatio-temporal evolution law of heat balance process of different land use types and heat flux process before, during and after urbanization in Yuelai New City were analyzed by satellite remote sensing image data and SEBAL model, the effect of land use/vegetation cover on surface heat flux was also discussed. The results include (1) the net radiation flux and difference of various land use types in Yuelai New City reached the maximum in July and the minimum in January, vegetation coverage was one of the factors affected sensible heat flux of different land use types. The order of latent heat flux was woodland > farmland > bare land > residential land, and the order of soil heat flux was bare land > residential land > woodland > farmland. (2)The urbanization process increased the area of low net radiation value in Yuelai New City, and sensible heat flux showed an increasing trend and accounted for the largest proportion in the energy output. The low value area of latent heat flux gradually expanded to the north and south. Soil heat flux and sensible heat flux were higher in the area with low latent heat flux. The distribution rules of soil heat flux and sensible heat were basically consistent, and both showed an increasing trend. (3)The correlation between soil heat flux and land use area was the best among the energy output factors. Fractional vegetation cover( FVC ) had a greater impact on heat fluxes than land use area. Residential combined land was most closely related to FVC , and latent heat flux was most affected by FVC .