合肥市城、郊气象要素及地气交换通量差异的观测研究

Experimental study on differences of meteorological elements and surface fluxes in urban and suburban Hefei

利用2013年1月5日~10月10日城、郊自动气象站和涡度相关系统观测数据,从气象要素、城市热岛强度、地表能量平衡三个方面定量分析了合肥市城、郊的差异.结果表明:①四个季节夜间热岛强度总是强于白天,而白天城市热岛并不明显.四季夜间热岛强度大小关系为冬季>秋季>春季>夏季.冬季晴天夜间热岛强度均值达到最大值1.97℃,夏季晴天夜间热岛强度均值达到最小值0.76℃.②城区以感热通量为能量支配的主要方式,郊区以潜热通量为能量支配的主要方式,城区日均形成不稳定层结时间比郊区长2.3 h.城区站点四季波文比起伏较大,冬季晴天最大为8.66,秋季晴天最小为0.95,四季波文比大小关系为冬季>春季>夏季>秋季.郊区站点四季波文比起伏较小,冬季晴天最大为1.65,秋季晴天最小为0.49.

Based on the data collected by the automatic weather station and the eddy correlation system from the urban and suburban areas in Hefei from 5 May to 10 October,2013,differences in the urban and suburban areas are quantitatively analyzed from three aspects:meteorological factors,urban heat island(UHI)intensity,and surface energy balance.The result shows:①UHI in the evening is stronger than that in the daytime,but not obvious in the daytime.The order of intensity of UHI in four seasons at night is winter>autumn>spring>summer.The average value of UHI intensity at night reached the maximum of 1.97℃on clear winter nights,and the minimum of 0.76℃was reached on clear summer nights.②The sensible heat flux played a major role in urban energy budget,while the latent heat flux played a major role in suburban energy budgets.The daily average time of unstable stratification in urban sites is 2.3 h longer than that in suburban areas.The Bowen ratio of the four seasons in the urban area fluctuated greatly,reaching the maximum of 8.66 on sunny days in winter,and the minimum of 0.95 on sunny days in autumn.The order of the Bowen ratio of four seasons in the urban area is winter>spring>summer>autumn.The Bowen ratio in the suburban area had less fluctuations in four seasons with the maximum being 1.65 on sunny days in winter and the minimum being 0.49 on sunny days in autumn.