干旱半干旱气候条件下夏季地表城市热岛特征与影响因素研究

利用MODIS土地利用产品提取城市建成区和郊区，以2013年6、7、8三个月的MODIS地表温度产品以及植被覆盖产品分析夏季甘肃省内干旱半干旱气候条件下的地表城市热岛特征，讨论影响地表城市热岛的主要因素。结果表明，在干旱半干旱气候条件下，地表城市热岛具有显著的昼夜差距与区域特点，表现为夜晚地表城市热岛强度大于白天；城市周围的农田、草地等生态屏障可以避免建成区地表被荒漠裸地直接包围，对于控制地表城市热岛具有重要作用，传统计算城郊温度差的方法对于衡量干旱半干旱气候条件下的地表城市热岛具有明显局限性；影响地表城市热岛的主要因素在一天中会产生变化，城郊植被覆盖度差异与夏季白天的地表城市热岛有显著相关性，夜晚地表城市热岛则可能与人类活动强度和人为热源排放有关。

Characteristics and influence factors of summer surface urban heat island under arid and semi-arid climate

Urban and rural areas were extracted from MODIS land product, the mean surface temperature of June, July, August in 2013 of the MODIS land surface temperature product and MODIS vegetation indices composite product were used to study the characteristics and factors influenced surface urban heat in summer under arid and semi-arid climate of Gansu province. Results show that in arid and semi-arid climate, surface urban heat island had significant difference between day and night and regional characteristics. Surface urban heat island intensity in nighttime is greater than daytime; Cropland, grassland and other ecological barrier avoided urban area directly surrounded by desert bare land and plays an important role to control the surface urban heat island, Traditional method to measure surface urban heat island under arid and semi-arid climate has obvious limitations; The main factors influenced surface urban heat island were changing in one day, the differences of vegetation coverage between urban and rural areas in summer were significantly correlated with surface urban heat island intensity in the daytime, for nighttime, the surface urban heat island may be related to the intensity of human activities and human heat emission.