城市地表净辐射通量的季相变化及与地表覆盖格局的关系研究

本研究利用厦门市4个季节的Landsat-5 TM遥感影像和气象资料,反演地表净辐射通量,进而分析其季相变化特征;使用景观格局指数表征和描述地表覆盖的空间组成与配置,采用相关分析、偏相关分析、逐步回归和方差分解相结合的方法,从多季节角度研究地表覆盖格局对地表净辐射通量的影响。结果表明：① 厦门市地表净辐射通量平均值夏季最高,春季次之,秋季和冬季较低,地表净辐射通量在水体和林地区域较高,建设用地和裸地等其他地表覆盖类型区域较低;② 地表覆盖的空间配置对地表净辐射通量没有显著影响;③ 地表覆盖的空间组成对地表净辐射通量产生重要影响,全年内林地和裸地所占面积比例对地表净辐射通量的影响最显著,林地所占面积比例是影响和解释地表净辐射通量跨季节差异的最重要和持续有效的因素。该研究加深了关于地表覆盖格局对地表净辐射通量的影响的科学认知,有助于探索城市热岛的形成和演变机制,也可为城市规划和可持续发展提供理论依据和实践指导。

Seasonal Variations of Urban Surface Net Radiation and Its Relationship to Land Cover Pattern

Rapid urbanization has led to land cover pattern changes which alter the surface net radiation and eventually influence surface energy balance. This process has been accompanied by a series of ecological and environmental problems, one of which is the urban heat island effect. Therefore, research on the seasonal variations of urban surface net radiation and its relationship to land cover pattern can provide important insights for exploring the formation and evolution mechanism of urban heat island. Taking Xiamen city as a study area, this research retrieved surface net radiation using Landsat-5 TM remote sensing images and meteorological data of the four seasons. Then the seasonal variation characteristics of surface net radiation were further analyzed. Landscape metrics were used to characterize and describe the spatial composition and allocation of land cover pattern. The correlation analysis, partial correlation analysis, stepwise regression analysis and variance partitioning were applied to explore the relationship between surface net radiation and land cover pattern from multi-seasonal perspective. The results suggest that: (1) the highest mean value of surface net radiation was found in summer, followed by spring, fall and winter. Surface net radiation is higher for the land cover types of water and forestland, while lower for built-up land and bare land. (2) The spatial allocation of land cover pattern has no significant influence on surface net radiation. (3) The spatial composition of land cover pattern shows significant influence on surface net radiation. The proportions of bare land and the proportion of forest land are effective and important factors which affect the changes of surface net radiation all the year round. And the proportion of forest land is the most important and continuously effective factor which affects and explains the cross-seasonal differences of surface net radiation. This research expands our scientific understanding of the effects of land cover pattern on surface net radiation. And it is helpful in exploring the formation and evolution mechanism of urban heat island. In addition, it may provide theoretical hints and realistic guidance for urban planning and sustainable development.