土地利用/覆被的剧烈变化对深圳市气温的影响
Impacts of Dramatic Land Use Change on the Near-Surface Air Temperature in Shenzhen

摘要 基于Landsat遥感影像解译得到1986年和2011年深圳市土地利用/覆被数据, 采用中尺度气候模式WRF/UCM, 在较高分辨率的地形资料和城市冠层参数支持下, 将两个时期的土地利用/覆被作为模式强迫参量, 分别进行两组数值模拟试验。将模拟结果与自动气象站点观测数据进行对比和验证, 发现WRF模式能够较准确地反映深圳市月平均气温西高东低的空间分布特征。1986—2011年, 深圳市在快速城市化进程中发生大规模的土地利用/覆被变化, 引起近地表气温整体上呈现增高趋势。其中, 7月增温幅度(0.91℃)普遍大于1月(0.42℃), 各种自然植被覆盖型用地转变成城镇建设用地的升温幅度大多为0.70~1.57℃。主要原因是城镇建设用地扩张导致地表反照率减小, 净辐射和感热通量增加, 潜热交换变弱。
Abstract Based on the Landsat remote sensing images of 1986 and 2011, higher resolution terrain data and 2-D urban fraction values, the impact of land use and land cover change (LUCC) on the near-surface air temperature is investigated for Shenzhen by carrying out two sets of numerical experiments using the weather research and forecasting model (WRF) coupled with the Noah urban canopy model. Comparison with measured near-surface air temperatures of 40 ground-based atmospheric observatories in the region shows a good agreement between observed and simulated data for the simulation periods. The results indicate significant contributions of urban sprawl and accompanying LUCC to the near-surface air temperature. Simulations suggest that LUCC has caused average temperatures with an increase of up to 0.42°C in January and 0.91°C in July respectively. The conversion from natural vegetation covers into urban and built-up area results in a decrease in surface albedo and thereby enhances the surface net solar radiation and the sensible heat flux, which leads to the most obvious warming effect.