Effects of meridional sea surface temperature changes on stratospheric temperature and circulation   总被引：4，自引：1，他引：3  

HU Dingzhu  TIAN Wenshou  XIE Fei  SHU Jianchuan  Sandip  DHOMSE 《大气科学进展》2014,31(4):888-900

Using a state-of-the-art chemistry-climate model,we analyzed the atmospheric responses to increases in sea surface temperature （SST）.The results showed that increases in SST and the SST meridional gradient could intensify the subtropical westerly jets and significantly weaken the northern polar vortex.In the model runs,global uniform SST increases produced a more significant impact on the southern stratosphere than the northern stratosphere,while SST gradient increases produced a more significant impact on the northern stratosphere.The asymmetric responses of the northern and southern polar stratosphere to SST meridional gradient changes were found to be mainly due to different wave properties and transmissions in the northern and southern atmosphere.Although SST increases may give rise to stronger waves,the results showed that the effect of SST increases on the vertical propagation of tropospheric waves into the stratosphere will vary with height and latitude and be sensitive to SST meridional gradient changes.Both uniform and non-uniform SST increases accelerated the large-scale Brewer-Dobson circulation （BDC）,but the gradient increases of SST between 60°S and 60°N resulted in younger mean age-of-air in the stratosphere and a larger increase in tropical upwelling,with a much higher tropopause than from a global uniform 1.0 K SST increase.  相似文献   

An Overview of BCC Climate System Model Development and Application for Climate Change Studies          下载免费PDF全文

WU Tongwen  SONG Lianchun  LI Weiping  WANG Zaizhi  ZHANG Hu  XIN Xiaoge  ZHANG Yanwu  ZHANG Li  LI Jianglong  WU Fanghu  LIU Yiming  ZHANG Fang  SHI Xueli  CHU Min  ZHANG Jie  FANG Yongjie  WANG Fang  LU Yixiong  LIU Xiangwen  WEI Min  LIU Qianxi  ZHOU Wenyan  DONG Min  ZHAO Qigeng  JI Jinjun  Laurent LI  ZHOU Mingyu 《Acta Meteorologica Sinica》2014,28(1):34-56

This paper reviews recent progress in the development of the Beijing Climate Center Climate System Model(BCC-CSM) and its four component models(atmosphere,land surface,ocean,and sea ice).Two recent versions are described:BCC-CSM1.1 with coarse resolution(approximately 2.8125°×2.8125°) and BCC-CSM1.1(m) with moderate resolution(approximately 1.125°×1.125°).Both versions are fully coupled climate-carbon cycle models that simulate the global terrestrial and oceanic carbon cycles and include dynamic vegetation.Both models well simulate the concentration and temporal evolution of atmospheric CO_2 during the 20th century with anthropogenic CO2 emissions prescribed.Simulations using these two versions of the BCC-CSM model have been contributed to the Coupled Model Intercomparison Project phase five(CMIP5) in support of the Intergovernmental Panel on Climate Change(IPCC) Fifth Assessment Report(AR5).These simulations are available for use by both national and international communities for investigating global climate change and for future climate projections.Simulations of the 20th century climate using BCC-CSMl.l and BCC-CSMl.l(m) are presented and validated,with particular focus on the spatial pattern and seasonal evolution of precipitation and surface air temperature on global and continental scales.Simulations of climate during the last millennium and projections of climate change during the next century are also presented and discussed.Both BCC-CSMl.l and BCC-CSMl.l(m) perform well when compared with other CMIP5 models.Preliminary analyses indicate that the higher resolution in BCC-CSM1.1(m) improves the simulation of mean climate relative to BCC-CSMl.l,particularly on regional scales.  相似文献   

Climatology of Lightning Activity over the Indian Seas     

M.I.R. Tinmaker  M.Y. Aslam 《大气与海洋》2014,52(4):314-320

The climatology of lightning activity over the Indian seas (Arabian Sea (AS) and Bay of Bengal (BoB)) has been studied using monthly satellite-based lightning flash count grid (0.5°?×?0.5°) data from 1998 to 2007. These data have been used to investigate the annual and seasonal variations in lightning activity over the Indian seas. It was found that annual variations in flash rate density and sea surface temperature (SST) show a bimodal pattern with the first peak occurring in May and the second in October. The correlation coefficients between flash rate density and SSTs are 0.76 and 0.65 for the AS and BoB, respectively. Further, the relationship between flash rate density and a low pressure system (LPS) over the BoB shows that the formation of severe tropical cyclonic storms starts during April with the maximum number of storms forming during August. The performance of monsoon on a seasonal and monthly basis depends on the total number of lows, the formation of a depression in the monsoon trough, and the number of days with an LPS. Secular decreases in the number of lows and monsoon depressions were observed in 2000, 2002, and 2004. Overall, results indicate that the peaks in SST during April and September/October over the AS and the BoB may be responsible for advancing the onset of the southwest and northeast monsoon by 30–40 days.  相似文献   

Western Arctic Cyclones and Equilibrium between the Atmospheric Boundary Layer and the Sea Surface     

R. L. Raddatz  R. J. Galley  B. G. Else  T. N. Papakyriakou  M. G. Asplin  L. M. Candlish 《大气与海洋》2014,52(2):125-141

The data-collection campaign for the 2008 International Polar Year–Circumpolar Flaw Lead System Study saw the Canadian Coast Guard Ship (CCGS) Amundsen, a research icebreaker, overwinter in high-concentration unconsolidated sea ice in Amundsen Gulf. Environmental monitoring continued into the open-water season. During this period, the Amundsen registered five relatively deep mean sea-level pressure minima (less than 100?kPa). Three were selected for further analysis based on season and the nature of the underlying ocean or sea-ice surface: (1) a winter pressure minimum over unconsolidated sea ice, (2) a spring pressure minimum which likely contributed to the break-up of the sea-ice cover on Amundsen Gulf, and (3) a summer pressure minimum over open water. The characteristics of these pressure minima and the impact of their passage on the atmospheric boundary layer and on the sea-ice cover as they crossed Amundsen Gulf were examined. Several features were revealed by the analysis. (1) The winter and summer pressure minima were migratory cyclones accompanied by Arctic frontal waves with characteristics very similar to the polar frontal waves associated with the migratory cyclones found at more southerly latitudes, whereas the spring pressure minimum was attributed to an Arctic frontal trough of low pressure with the cyclonic centre remaining south of the Gulf. (2) The passage of the frontal-wave cyclone in winter and the frontal trough of low pressure in spring disrupted the equilibrium that had been established during more settled periods between the atmospheric boundary layer and the mosaic surface (leads, polynyas, and sea ice); however, equilibrium was quickly re-established. (3) In summer, the thermal structure of the lower atmospheric boundary layer persisted through the passage of the frontal-wave cyclone over the open-water surface. (4) The passage of the frontal-wave cyclone in winter and the frontal trough of low pressure in spring modified the mesoscale sea-icescape.  相似文献   

The Observed and Simulated Major Summer Climate Features in Northwest China and Their Sensitivity to Land Surface Processes          下载免费PDF全文

LI Qian  XUE Yongkang 《Acta Meteorologica Sinica》2014,28(5):836-848

Northwest China （NWC） is a typical arid and semi-arid region. In this study, the main summer climate features over NWC are presented and the performance of an atmospheric general circulation model （NCEP GCM/SSiB） over this region is evaluated. Satellite-derived vegetation products are applied in the model. Based on comparison with observational data and Reanalysis II data, the model generally captures major features of the NWC summer energy balance and circulation. These features include： a high surface tem- perature center dominating the planetary boundary layer; widespread descending motion; an anticyclone （cyclone） located in the lower and middle （upper） troposphere, covering most parts of central NWC; and the precipitation located mainly in the high elevation areas surrounding NWC.
The sensitivity of the summer energy balance and circulation over NWC and surrounding regions to land surface processes is assessed with specified land cover change. In the sensitivity experiment, the degradation over most parts of NWC, except the Taklimakan desert, decreases the surface-absorbed radiation and leads to weaker surface thermal effects. In northern Xinjiang and surrounding regions, less latent heating causes stronger anomalous lower-level anticyclonic circulation and upper-level cyclonic circulation, leading to less summer precipitation and higher surface temperature. Meanwhile, the dry conditions in the Hexi Corridor produce less change in the latent heat flux. The circulation change to the north of this area plays a domi- nant role in indirectly changing lower-level cyclonic conditions, producing more convergence, weaker vertical descending motion, and thus an increase in the precipitation over this region.  相似文献   

北京气候中心气候系统模式研发进展——在气候变化研究中的应用   总被引：4，自引：2，他引：2  

吴统文  宋连春  李伟平  王在志  张华  辛晓歌  张艳武  张莉  李江龙  吴方华  刘一鸣  张芳  史学丽  储敏  张洁  房永杰  汪方  路屹雄  刘向文  魏敏  刘茜霞  周文艳  董敏  赵其庚  季劲钧  Laurent Li  周明煜 《气象学报》2014,72(1):12-29

较全面地介绍了北京气候中心气候系统模式(BCC_CSM)研发所取得的一些进展及其在气候变化研究中的应用,重点介绍了全球近280 km较低分辨率的全球海-陆-气-冰-生物多圈层耦合的气候系统模式BCC_CSM1.1和110 km中等大气分辨率的BCC_CSM1.1(m),以及大气、陆面、海洋、海冰各分量模式的发展。BCC_CSM1.1和BCC_CSM1.1(m)气候系统模式均包含了全球碳循环和动态植被过程。当给定全球人类活动导致的碳源排放后,就可以模拟和预估人类活动对气候变化的影响。BCC_CSM1.1和BCC_CSM1.1(m)已应用于IPCC AR5模式比较,为中外开展气候变化机理分析和未来气候变化预估提供了大量的试验数据。还介绍了BCC_CSM1.1和BCC_CSM1.1(m)参与国际耦合模式比较计划(CMIP5)的大量试验分析评估结果,BCC_CSM能够较好地模拟20世纪气温和降水等气候平均态和季节变化特征,以及近1000年的历史气候变化,所预估的未来100年气候变化与国际上其他模式的CMIP5试验预估结果相当。初步的分析表明,分辨率相对高的BCC_CSM1.1(m)在区域气候平均态的模拟上优于分辨率较低的BCC_CSM1.1。  相似文献   

基于多时相遥感的鄂尔多斯市不透水面变化分析     

赵传武  吴子若  张玉环  郭伟 《测绘通报》2022,(5):56-61

不透水面作为城市发展和生态环境的重要评估因子,在保障生态环境健康和城市可持续发展中具有重大意义。本文以鄂尔多斯为研究区,通过融合多时相Landsat和夜间灯光数据,提取1990—2019年的不透水面信息,并利用重心分析法、标准差椭圆理论和景观指数理论分析时空演变规律。研究结果表明:①1990—2019年鄂尔多斯市不透水面经历了快速扩张;东北部不透水面覆盖度高于西南部;不透水面的扩张模式总体上表现为“向外扩张-向内加密”。②东北部扩张速度减缓,西南部扩张速度增快。③不透水面扩张的方向性减弱;不透水面扩张的方向有由“东北-西南”向“东-西”转变的趋势。④斑块数量及边缘斑块破碎度增加,城市与郊区的连通性增强,城市有向周边郊区扩张的趋势。本文研究对于进一步了解城市生态环境健康与城市可持续发展的相关关系具有一定的参考价值。  相似文献   

基于空间变异修正普通克里金的矿区复杂地形高精度建模     

于广婷  刘同文  王琦  潘懋  李涛  宋冠涵  刘善伟 《测绘通报》2022,(11):106-111

普通克里金法是构建矿区三维地形模型并揭示地表沉陷形变场动态变化规律的有效方法。但普通克里金法存在平滑效应的问题,导致估计值的空间变异程度小于实际,无法真实反映矿区复杂地表形态的空间变化特征。本文结合矿区实际地形采样数据,提出了一种空间变异修正的普通克里金法,并将其应用于矿区复杂地形的高精度建模,并与已有方法在建模精度和空间变异性复现方面进行了对比分析。研究结果表明,空间变异修正的普通克里金法能够很好地处理平滑效应对建模的影响,具有更高的建模精度和空间变异性复现能力,在矿区复杂地形高精度建模应用中具有较强的适用性,可以作为一种可靠的建模工具用于矿区复杂地形沉陷形变场动态变化规律分析。  相似文献   

多空间尺度下城市热环境与不透水面聚集密度响应关系     

孟庆岩  王子安  张琳琳  孙震辉  胡蝶  杨天梁 《遥感学报》2022,26(9):1789-1801

针对以往城市热环境与不透水面聚集密度响应规律研究不足的问题,本文以北京市为例,基于MODIS 数据计算城建区与边缘区平均温度差值为热岛强度,结合热岛强度等级特征,选取热岛强度等级期望值较高的6个典型区域（Ⅰ西二旗、西三旗、回龙观,Ⅱ东四、地安门、新街口,Ⅲ丰台区中部,Ⅳ四惠、定福庄、东坝,Ⅴ石景山区,Ⅵ北四环四季青桥附近）,研究热岛强度等级与不透水面聚集密度的响应关系;进而利用Landsat数据反演地表温度,研究城建区与精细尺度下地表温度对不透水面聚集密度响应临界点与最优尺度。结果表明：（1）不同热岛强度等级的出现频率、其在白天与夜间的变化程度与不透水面聚集密度有一定相关性,且相近的不透水面聚集密度下所表现出热岛强度的变化特征相似。（2）主要城建区内地表平均温度与不透水面聚集密度的分布特征存在较显著的一致性,随着尺度半径r的增大其响应越明显。且地表温度对不透水面聚集密度的响应存在一个临界点,随着尺度半径r减小,响应临界点逐渐增大：尺度半径r=1000 m时,不透水面聚集密度达到60%后其影响趋于减弱;r=500 m、r=300 m时临界点分别为69%与83%。（3）不同典型区域的最优尺度存在差异,西二旗、西三旗、回龙观最优尺度为150 m,东四、地安门、新街口与四环四季青桥附近为60 m,而季节变化对最优尺度的影响较小。该最优尺度可在一定程度上衡量不同区域不透水面分布的破碎程度及地表类型的单一程度。本研究可为城市规划与管理、城市热岛治理提供参考依据。  相似文献   

岩溶峰丛洼地勘察方法研究     

咸云尚 《四川地质学报》2014,(2):225-227

以桂林市郊区某变电站工程为例,在地面调查、钻探及高密度电法测试的基础上,分析了峰丛洼地的岩溶发育特征。强调了地面调查在岩溶勘察中的重要性。  相似文献