一个区域地气耦合柱状模式的发展及其对半干旱区的模拟

在现有的区域气候模式的基础上构建了用于研究地气耦合模拟的区域柱状模式,其中包括了详细的物理过程,可以作为研究半干旱区地气相互作用过程的工具。通过区域柱状模式与不同陆面模式的耦合,检验了不同陆面模式在非耦合和耦合两种情况下对半干旱区的模拟性能。结果表明,陆面模式在耦合后对感热的模拟偏差放大,而潜热的模拟效果得到了改进,不同的陆面模式对区域柱状模式的模拟性能影响较大,耦合了CoLM后的区域柱状模式对地表气象要素的模拟得到了较大的改进。     

Global and Regional Impacts of Vegetation on the Hydrological Cycle and Energy Budget as Represented by the Community Atmosphere Model （CAM3）

The effects of vegetation and its seasonal variation on energy and the hydrological cycle were examined using a state-of-the-art Community Atmosphere Model （CAM3）. Three 15-year numerical experiments were completed： the first with realistic vegetation characteristics varying monthly （VEG run）, the second without vegetation over land （NOVEG run）, and the third with the vegetation characteristics held at their annual mean values （VEGMEAN run）. In these models, the hydrological cycle and land surface energy budget were widely affected by vegetation. Globaland annual-mean evapotranspiration significantly increased compared with the NOVEG by 11.8% in the VEG run run, while runoff decreased by 13.2% when the realistic vegetation is incorporated. Vegetation plays different roles in different regions. In tropical Asia, vegetation-induced cooling of the land surface plays a crucial role in decreasing tropical precipitation. In middle latitudes and the Amazon region, however, the vegetation-induced increase of evapotranspiration plays a more important role in increasing precipitation. The seasonal variation of vegetation also shows clear influences on the hydrological cycle and energy budget. In the boreal mid-high latitudes where vegetation shows a strong seasonal cycle, evapotranspiration and precipitation are higher in the summer in the VEG run than in the VEGMEAN run.     

全球变化与区域干旱化

本文总结了已完成的国家重点基础研究发展规划计划项目(“973”项目)“我国生存环境演变和北方干旱化趋势预测”(1999～2004年)和正在执行的“973”项目“北方干旱化与人类适应”的有关干旱化问题研究的部分成果。主要是中国科学院大气物理研究所最近几年在近代区域干旱化的事实及全球联系方面的研究进展,并对全球增暖背景下区域干旱化的形成机理展开讨论。     

中国当代土地利用变化对黄河流域径流影响

使用区域气候模式(RegCM3)和大尺度汇流模型(LRM),研究中国地区土地利用/植被覆盖变化对黄河流域降雨径流过程的影响。RegCM3嵌套于欧洲数值预报中心(ECMWF)再分析资料ERA40,分别进行了中国区域在实际植被和理想植被分布情况下两个各15年(1987～2001年)时间长度的积分试验。随后,RegCM3 两个试验的输出径流结果分别用来驱动LRM。与观测资料的对比分析表明,在实际土地利用状况下,LRM能较好地模拟黄河河川径流的季节和年际变化。研究结果指出,当代土地利用引起了冬季黄河上游部分地区降水减少,中下游地区降水增加;引起夏季整个黄河流域降水的减少。总体来说,当代土地利用变化引起黄河流域年平均降水的减少。对于水文站河川径流量,除了冬春季略有增加外,其他月份河川径流均会减少,并且在9月减少最多。土地利用引起的植被退化造成黄河径流的大幅度减少,并且越向下游减少幅度越大,这可能是引起黄河下游断流的重要原因之一。     

Role of reservoir regulation and groundwater feedback in a simulated ground-soil-vegetation continuum: A long-term regional scale analysis

The regional terrestrial water cycle is strongly altered by human activities. Among them, reservoir regulation is a way to spatially and temporally allocate water resources in a basin for multi-purposes. However, it is still not sufficiently understood how reservoir regulation modifies the regional terrestrial- and subsequently, the atmospheric water cycle. To address this question, the representation of reservoir regulation into the terrestrial component of fully coupled regional Earth system models is required. In this study, an existing process-based reservoir network module is implemented into NOAH-HMS, that is, the terrestrial component of an atmospheric–hydrologic modelling system, namely, the WRF-HMS. It allows to quantitatively differentiate role of reservoir regulation and of groundwater feedback in a simulated ground-soil-vegetation continuum. Our study focuses on the Poyang Lake basin, where the largest freshwater lake of China and reservoirs of different sizes are located. As compared to streamflow observations, the newly extended NOAH-HMS slightly improves the streamflow and streamflow duration curves simulation for the Poyang Lake basin for the period 1979–1986. The inclusion of reservoir regulation leads to major changes in the simulated groundwater recharges and evaporation from reservoirs at local scale, but has minor effects on the simulated soil moisture and surface runoff at basin scale. The performed groundwater feedback sensitivity analysis shows that the strength of the groundwater feedback is not altered by the consideration of reservoir regulation. Furthermore, both reservoir regulation and groundwater feedback modify the partitioning of the simulated evapotranspiration, thus affecting the atmospheric water cycle in the Poyang Lake region. This finding motivates future research with our extended fully coupled atmospheric–hydrologic modelling system by the community.     

江苏数字地震台网P波谱震级和地震辐射能的计算

基于江苏数字地震台网的宽频带记录,对38次M≥5.0地震的P波谱震级M_P进行测定,对地震的辐射能量进行了估算。结果表明:本文测定的M_P与中国地震台网中心(CENC)测定的MS、德国地学中心(GFZ)测定的MW具有很好的一致性,与该2种震级之间的平均偏差分别约为0.17和0.10级,基本小于世界主要地震机构之间对同一震级的测定误差(约0.2级);同时,基于M_P估算的地震辐射能与基于修正G-R关系由MS震级换算获得的结果十分接近,两者平均能量之比约为1.1,表明M_P与P波群(P+pP+sP)能量流是基本等效的。因此,基于宽频带数字记录测定中强地震的P波谱震级以及地震辐射能是可行的,且测定过程简便。     

人工主余震作用下桥墩结构损伤预测评估分析

主余震作用下,断层距（R_JB）和余震次数的不同对结构造成的损伤也大不相同,进行主余震序列下桥梁损伤评估时需要考虑断层距、余震次数等影响因素。基于OpenSees平台,以一座连续梁桥为例,根据人工主余震构造时不同的影响因素,选用余震衰减和PGA调幅的人工主余震构造法构造主余震序列进行结构损伤分析,并与实际主余震事件的损伤结果作对比,研究人工构造主余震序列预测结构损伤的可行性。结果表明：基于PGA调幅构造主余震的方法,当考虑余震衰减时,能够较好模拟出结构在实际主余震地震作用下造成的最终损伤,能够较合理的预测结构在实际主余震序列中的损伤指标;对区域主余震作用下的桥梁进行损伤评估时,需要考虑断层距和余震次数影响因素,桥梁距断层距R_JB越近时结构的损伤状态越严重,余震发生次数越多则结构的损伤增量就越大,并且结构在人工主余震作用下R_JB越大的地方,结构损伤增量误差程度越小,预测的损伤状态就越接近实际的损伤状态。     

湖南省地市经济差异综合评价及分区研究

文章运用主成分分析的数理统计方法,选择14项指标,对湖南省地市经济发展水平的区域差异进行了综合评价和区域聚类划分。评价结果表明:湖南各地市的经济发展水平存在明显差异,可划分为5个层次。在此基础上,文章还提出了实现地市经济协调发展的对策:重视经济发展效率;坚持"点-轴"开发模式,优化空间开发结构;加快长株潭发展极产业一体化发展步伐等。     

基于城市竞争力提高的旅游业发展研究--以苏州市为例

中国城市的旅游黄金时代即将到来。城市决策者应当意识到,旅游业的发展并不只是旅游专业部门的事情,旅游业作为一种经济“催化剂”,将成为城市产业发展乃至增强城市竞争力的一个制高点。文章把旅游业发展和城市整体联系起来,以苏州市为例,指出苏州应充分利用其优越的旅游资源,延伸旅游产业的外在价值。最后,从提高城市竞争力的角度,对苏州旅游业的发展提出了战略构想。