长江中下游地区城市化进程中地表植被变化气候效应的数值模拟  

Numerical simulation of the climate effect of the urbanization course along the middle and lower reaches of Yangtze River

作　　者：董喜春[1] 汤剑平[1] 王元[1] 俞剑蔚[2] 

机构地区：[1]南京大学大气科学系 [2]江苏省气象台,南京210008

出　　处：《气象科学》2008年第2期147-154,共8页Journal of the Meteorological Sciences

基　　金：江苏省自然科学基金(BKD2005081、BK99020)

摘　　要：利用高分辨率区域气候模式RegCM3,对长江中下游地区城市化进程中土地利用的变化引起的地气能量交换和水份收支改变的气候效应进行模拟研究。结果表明:下垫面由农田变为城市后近地层大气水汽含量减小,气温升高。但增温幅度存在明显的时空差异,总体而言西部高于东部、夏季高于冬季。对能量平衡的各因子的分析表明,因地表水份蒸发引起的潜热释放减少是地表温度增加最主要的原因。流场差异场的特点是以试验区域为中心,低层呈气旋性而高层呈反气旋性环流,这种结构特征有利于试验区域以外中低层大气以补偿性平流的形式流入试验区,补充地表水份损失,导致退化试验和控制试验相比低层云水量减少而中高层云水量增加。受环流场和水汽场异常的共同影响,夏季试验区域西部平均降水减少而东部增加。绿化试验和过渡试验结果则表明,当城市绿化面积超过50%时,能够有效地减小城市化进程对局地气候的影响。A new regional climate model-RegCM3 is used to simulate the climatic effects of vegetation type changes on the process of the urbanization course along the middle and lower reaches of Yangtze River. The results show that vegetation type changes from cropland to urban underlying surface results in the decrease of moisture and increase of the temperature in the surface layer. The apparent spatial and temporal differences are found that the heating rate in summer is higher than in winter, and the west subregion is warmer than the east. This paper shows that the decrease of latent heat release is the chief factor causing the ground temperature rising. For the difference of wind field, the pattern is featured as cyclonic flow at low level and anticyclonic flow at high level. This structure may be helpful to the flow from outside to inside with a compensation current character. The result of moisture supplementation is the increase of cloud cover fraction at high level. Both the abnormality of the circulation and moisture field affect the precipitation distribution. It is also found from the comparison of the greening experiment and control experiment that the climate effect of the urbanization course may be significantly depressed.

关 键 词：城市化 植被类型 气候效应 绿化 

分 类 号：P461.7[天文地球—大气科学及气象学]