山地新城市化进程的地表热通量时空演变--以悦来新城为例

Spatio-temporal Evolution of Surface Heat Flux During New Urbanization in Mountainous Areas:A Case Study of Yuelai New City

山地城市通常因为地形复杂、气候多变使得局地的地表热通量分布规律与平原城市有较大区别。为探求山地新开发区城市化进程中的地表热通量时空演变规律,利用卫星遥感影像资料和LUMPS、SEBS模型,对代表重庆市未来发展窗口的悦来新城不同土地利用类型的热平衡过程和城市化前、中、后3期的各热通量过程时空演变规律进行了分析,并探讨了土地利用/植被覆盖对各地表热通量的影响,结果表明:(1)悦来新城各土地利用类型的净辐射通量及差值在7月份最大,1月份最小,植被覆盖度是不同土地利用类型显热通量存在差异的因素之一,潜热通量依次为:林地>农田>未利用土地>居民用地,土壤热通量依次为:未利用土地>居民用地>林地>农田;(2)城市化进程使得悦来新城的净辐射低值区域增多,显热通量呈增加趋势且在能量输出中占比最多,潜热通量的低值区有向南北逐渐扩张的趋势,在潜热通量较低的地区土壤热通量和显热通量较高;土壤热通量与显热的分布规律基本一致,均呈增大趋势;(3)土壤热通量与土地利用面积的相关关系是各能量输出因子中最好的;植被覆盖度对各热通量的影响远大于土地利用面积,居民组合用地与植被覆盖度关系最为密切,潜热通量受植被覆盖度的影响最大。

The distribution of local surface heat flux in mountainous cities is quite different from that in plain cities because of complex terrain and changing climate.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,LUMPS and SEBAL model,the effect of land use/vegetation cover on surface heat flux was also discussed.The results show that,(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 affectied sensible heat flux of different land use types.the order of latent heat flux was forest land>farmland>unused land>residential land,and the order of soil heat flux was unused land>residential land>forest land>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.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.