中文摘要：

基于城市流强度模型测算2000年以来长江经济带126个地级以上城市在全国范围内的对外服务能力,进而采用改良锡尔系数、马尔可夫链和ESDA方法对城市对外服务能力的时空演变特征进行探讨。结果表明：研究时段内长江经济带各市城市流强度都有显著提升,但区域间的非均衡现象明显,城市对外服务能力呈现出由东部向西部的梯度递减;省内差异对城市对外服务能力的差异贡献率最高,是空间尺度差异的主要来源;对外服务能力存在明显的俱乐部趋同现象和空间自相关性,对外服务能力相似的区域聚集分布,东、中、西部分别形成长三角、武汉-长沙、成渝等对外服务区域中心;时空演变表现出阶段性特征,经历由极化向均衡的转变。最后指出多中心发展和寻找新增长点应成为长江经济带城市对外服务能力提升的方向。

英文摘要：

Increasing researches have focused on the Yangtze Economic Belt because this economic belt is recognized as the key point for regional development. Studying urban external service capability is an important subject on the Yangtze Economic Belt. The urban external capability is the embodiment of a city＇s agglomeration and radiation function. It refers to the city＇s ability to provide goods and services for the surrounding areas and can reflect the central position of the city in the region. In this article we quantitatively measured urban external service capability based on the urban flow intensity model, then comprehensively used the modified Theil index, Markov chains and exploratory spatial data analysis to analyze the spatio-temporal evolution of external service capabilities of 126 prefecture-level cities of 11 provinces and municipalities in the Yangtze Economic Belt since 2000. Results showed that：（1） Urban flow intensity value had an obvious increase during the study period, but different cities had different growing characteristics. The incremental and the increasing speed of eastern cities were the greatest which overtook both the central and the western region. The urban flow intensity of the urban agglomerations in the Yangtze Delta accounted for nearly half of the all.（2） The modified Theil Index showed that external service capabilities of the Yangtze Economic Belt presented spatial differentiation within province, which had a contribution of 41–48% to the total variation. The contributions at different spatial scales had different evolution trends. The contribution of differences within province increased, the contribution of differences between provinces first increased then decreased, and the contribution of differences between regions decreased.（3） There existed an obvious phenomenon of ‘Club Convergence＇ in urban external service capability in the Yangtze Economic Belt,combining with ESDA analysis; the spatial and temporal patterns were significant. Urban external servic