珠三角城市群热岛及其气象影响因子研究

STUDY ON THE URBAN HEAT ISLANDS AND METEOROLOGICAL ELEMENTS OVER THE PEARL RIVER DELTA

城市群热岛效应的合理评估关系到城市化对区域气候和环境的影响研究。以珠三角城市群为分析对象,并将其划分为东中西三个区,分析1999—2008年20个气象观测站资料,利用实测气温标准差方法定量选取郊区代表站,通过城郊对比方法研究热岛的时空特征及其气象影响因子,结果表明:珠三角平均热岛强度为0.71℃,线性增加趋势为0.29℃/(10 a)。热岛强度空间结构呈纬向三极子分布,广州、佛山、东莞和深圳等经济发达城市为高强度带,东西两侧逐渐减弱为两个低强度中心。热岛强度秋强(1.06℃)春弱(0.39℃)的季节变化和夜强(0.91℃)昼弱(0.53℃)的日变化特征明显。影响热岛出现频率的气象因子依次为低云量、相对湿度、风速和降雨量,并表现为负相关。研究结果对珠三角城市群的发展规划及气象和环境风险区划有良好借鉴意义。

Scientific evaluation of urban heat islands（UHI） over city clusters is important for the study of urbanization effects on regional climate and environment. In this paper, UHI and meteorological elements over the Pearl River Delta（PRD） are investigated using data measured at 20 meteorological observation stations during the period of 1999—2008. A standard deviation method is adopted to choose suburb stations by calculating UHI intensity over three zones in PRD. The average UHI intensity is 0.71 ℃ and the linear trend is 0.29 ℃/（10 a）. The spatial distribution of UHI presents a tri-pole pattern, in which the UHI intensity in the middle zone of PRD is higher than in the east and west zone. The average UHI shows clearly seasonal and diurnal changes, which is weakest in spring（0.39 ℃） and strongest in autumn（1.06 ℃）, and higher during nighttime（0.91 ℃） than in daytime（0.53 ℃）. The UHI intensity decreases with increasing low-cloud cover, relative humidity, wind speed and precipitation. The results may contribute to urban planning and zoning of meteorological and environmental risk in PRD.