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41.
以中国280个城市市辖区为研究对象,从暴露度、敏感性、适应能力3个维度构建城市高温脆弱性评价指标体系,利用气象观测数据、人口普查数据、社会经济统计数据等,量化城市高温脆弱性指数,揭示1990、2000和2010年中国城市高温脆弱性格局,并探讨其影响因素。结果显示：1）在时间维度上,1990－2010年中国城市高温暴露度呈升高趋势,敏感性先升高后降低,而适应能力呈缓慢降低趋势;空间维度上,暴露度整体呈南高北低的集聚态势,敏感性与适应能力分布则较分散。2）1990－2000年,中国城市高温脆弱性格局变化较小,2010年中国城市高温暴露度和敏感度均升高,适应能力却有所下降,导致高脆弱性城市数量骤增,分布范围呈由南向北扩大趋势,1990、2000、2010年高脆弱性城市占比依次为24%、28%、62%。3）区域气候条件、自然环境和城市发展水平的差异是影响城市高温脆弱性的重要因素,夏季月平均气温、热岛强度对城市高温脆弱性具有显著正向影响,人均地方财政收入、夏季月平均降水量、第二产业产值占GDP比重、高程、最大风速和人均固定资产投资额对城市高温脆弱性具有显著负向影响。气温对于城市高温脆弱性正向效应远大于城市社会经济条件的负向效应,城市高温脆弱性主要受区域温度环境的影响。 相似文献
42.
徐飞鹏副厅长在5月31日召开的全省国土资源法制工作培训班上强调,新形势、新任务对国土资源管理工作提出了新的更加严格的要求。各级国土资源法制工作者要认清形势,明确任务,努力提高适应能力,实现国土资源法制工作新跨越。 相似文献
43.
Over the last several decades,various sediment transport capacity formulations have been used by geomorphologists and engineers to calculate fluvial morphological changes.However,it remains poorly understood if the adaptation to capacity could be fulfilled instantly in response to differing inflow discharges and sediment supplies,and thus if the calculation of morphological changes in rivers based on the assumed capacity status is fully justified.Here we present a numerical investigation on this issue.The distance required for sediment transport to adapt to capacity（i.e.,adaptation-to-capacity length） of both bed load and suspended sediment transport is computationally studied using a coupled shallow water hydrodynamic model,in line with varied inlet sediment concentrations.It is found that the adaptation-to-capacity length generally decreases as the Rouse number increases,irrespective of whether the inlet sediment concentration increases or reduces.For cases with vanishing inlet sediment concentration a unified relationship is found between the adaptation-to-capacity length and the Rouse number.Quantitatively,the adaptation-to-capacity length of bed load sediment is limited to tens of times of the flow depth,whilst that of suspended sediment increases substantially with decreasing Rouse number and can be up to hundreds of times of the flow depth.The present finding concurs that bed load sediment transport can adapt to capacity much more rapidly than suspended sediment transport,and it facilitates a quantitative criterion on which the applicability of bed load or suspended sediment transport capacity for natural rivers can be readily assessed. 相似文献
44.
