Energy exchange in a dense urban environment - Part I: Temporal variability of long-term observations in central London
Energy exchange in a dense urban environment - Part I: Temporal variability of long-term observations in central London
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DOI：
10.1016/j.uclim.2013.10.002
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发表时间：
2014-12-01
期刊：
影响因子：
6.4
通讯作者：
Grimmond, C. S. B.
中科院分区：
文献类型：
--
作者：
Kotthaus, Simone;Grimmond, C. S. B.
虽然在人口密集的城市地区，人类活动对边界层气候的影响预计会很大，但迄今为止，关于能流观测的研究很少。我们报告收集在英国伦敦市中心的3.5年的测量。在不同的时间尺度上并结合云量等气象条件，对两个相邻地点不同高度的辐射计和涡动协方差观测结果进行了分析。虽然由于低水分可用性和主要不透水表面，蒸发通量通常较小，但降雨后的增强通常持续12-18 h。由于下午潜热通量和感热通量都较大，因此它们在整个中午保持相对一致的鲍文比。强的储存和人为热通量维持高的和持续的正感热通量。在月时间尺度上，城市地表通过这种湍流热通量损失的能量往往比从净全波辐射中获得的能量要多。辅助的人为热通量信息表明，在研究区域的人类活动足以提供这种能量。(C)2013 Elsevier B.V.
Though anthropogenic impacts on boundary layer climates are expected to be large in dense urban areas, to date very few studies of energy flux observations are available. We report on 3.5 years of measurements gathered in central London, UK. Radiometer and eddy covariance observations at two adjacent sites, at different heights, were analysed at various temporal scales and with respect to meteorological conditions, such as cloud cover. Although the evaporative flux is generally small due to low moisture availability and a predominately impervious surface, the enhancement following rainfall usually lasts for 12-18 h. As both the latent and sensible heat fluxes are larger in the afternoon, they maintain a relatively consistent Bowen ratio throughout the middle of the day. Strong storage and anthropogenic heat fluxes sustain high and persistently positive sensible heat fluxes. At the monthly time scale, the urban surface often loses more energy by this turbulent heat flux than is gained from net all-wave radiation. Auxiliary anthropogenic heat flux information suggest human activities in the study area are sufficient to provide this energy. (C) 2013 Elsevier B.V.