冬季影响北疆高速公路行车安全的气象要素特征分析     

吴彦  江远安  王胜利 《沙漠与绿洲气象(新疆气象)》2010,4(2):6-11

利用1961—2007年长达47a高速、高等级公路沿线气象站的资料,重点研究北疆高速、高等级公路沿线冬季影响车辆安全行驶的气象要素的气候特征,分析该路段降雪、积雪、结冰、冻雨等气象要素的时间和空间分布,并依据气候分布特点从气候的角度将北疆高速、高等级公路沿线路段按降雪、积雪、结冰、冻雨等对行车安全影响程度划分为极易打滑路段、较易打滑路段、易打滑路段和不易打滑路段,为公路管理部门提供科学的、合理的防御和减少冬季交通事故的理论依据。  相似文献   

乌鲁木齐及周边城市空气质量变化特征及影响因素分析     

刘新春  钟玉婷  何清  郭志忠 《沙漠与绿洲气象(新疆气象)》2010,4(2):12-17

利用美英等国5个海气耦合气候模式对黑龙江省(主要包括哈尔滨、齐齐哈尔、牡丹江和佳木斯4个地区)年、季平均气温前后近100 a进行模拟和预测结果,预估黑龙江省哈尔滨、齐齐哈尔、牡丹江和佳木斯4个城市气候变暖情景下未来100 a的采暖降温气候条件.可以为黑龙江省适应未来气候变化提供依据,为政府决策和能源公司做长远规划提供参考.  相似文献   

Consistency Problem with Tracer Advection in the Atmospheric Model GAMIL     

ZHANG Kai  WAN Hui  WANG Bin  ZHANG Meigen 《大气科学进展》2008,25(2):306-318

The radon transport test, which is a widely used test case for atmospheric transport models, is carried out to evaluate the tracer advection schemes in the Grid-Point Atmospheric Model of IAP-LASG （GAMIL）. Two of the three available schemes in the model are found to be associated with significant biases in the polar regions and in the upper part of the atmosphere, which implies potentially large errors in the simulation of ozone-like tracers. Theoretical analyses show that inconsistency exists between the advection schemes and the discrete continuity equation in the dynamical core of GAMIL and consequently leads to spurious sources and sinks in the tracer transport equation. The impact of this type of inconsistency is demonstrated by idealized tests and identified as the cause of the aforementioned biases. Other potential effects of this inconsistency are also discussed. Results of this study provide some hints for choosing suitable advection schemes in the GAMIL model. At least for the polax-region-concentrated atmospheric components and the closely correlated chemical species, the Flux-Form Semi-Lagrangian advection scheme produces more reasonable simulations of the large-scale transport processes without significantly increasing the computational expense.  相似文献   

山东省远距离热带气旋暴雨研究   总被引：22，自引：2，他引：20  

杨晓霞  陈联寿  刘诗军  薛德强  陈文选 《气象学报》2008,66(2):236-250

应用1971-2003年的山东降水资料、常规天气图资料、台风年签和NCEP资料,对在华南沿海登陆和活动的热带气旋在山东造成远距离暴雨的气候特征进行统计分析,对环流形势场进行合成分析.建立了山东省远距离热带气旋暴雨的天气学模型.分别计算分析了山东有和无远距离热带气旋暴雨合成的水汽和温湿能的收支.结果表明:在华南沿海登陆和活动的热带气旋与西风带环流系统和副热带高压相互作用在山东造成的远距离热带气旋暴雨年均2.5次.暴雨的范围广、强度大.出现暴雨的时间比热带气旋登陆时间滞后.在山东造成远距离暴雨的热带气旋在华南沿海登陆时,中心东部有一股东南风或偏南风低空急流指向内陆.中高纬度中低层西风带环流弱,位置偏北.500 hPa西风带中的偏北气流与副高边缘的偏南气流在山东境内汇合.低层850-700 hPa伴有低值系统影响,山东为气旋性环流控制.热带气旋登陆后其中心附近的中低层偏南风急流向北伸展,绕过副高脊线直达山东.在台风中心附近至山东之间建立起水汽和温湿能的输送通道,把高温高湿的暖湿空气源源不断地向山东输送.在台风登陆后12-48小时内,山东暴雨区上空有大量的水汽和温湿能的净流入.暖湿气流与西风带气流相汇合,产生辐合上升,造成暴雨.  相似文献   

印度夏季风与中国华北降水的遥相关分析及数值模拟   总被引：4，自引：0，他引：4  

刘芸芸  丁一汇 《气象学报》2008,66(5):789-799

20世纪80年代中国学者揭示了印度夏季风与中国华北降水的正相关关系,以后国内外又有一些研究证实了这种正相关关系的存在.文中利用1951-2005年多种气象资料和数值模拟方法,详细讨论了印度夏季风和中国华北地区夏季降水的关系,并针对由印度西北部经青藏高原到中国华北地区形成的正、负、正的遥相关型,从动力因子和热力因子两方面探讨了其中的内在联系,所得结果不但确证了以往的结论,而且进一步揭示了印度夏季风对华北地区降水的影响机制.结果表明:(1)印度夏季风强(弱)时,华北地区容易出现降水偏多(少)的天气;华北地区降水偏多(少)时,印度夏季风偏强(弱)的机率却低一些,这说明印度夏季风的异常变化对华北地区夏季降水有更大的影响.(2)印度夏季风强度主要受印度季风槽的影响,在印度季风槽加深的同时,中高纬的低压槽也加深发展,而这时西太平洋高压脊西伸,来自低纬的西南风水汽输送和源于西太平洋的副热带高压南侧的东南风水汽输送共同作用,有利于华北地区的降水偏多;反之则不利于华北地区的降水.(3)区域气候模式模拟结果也很好地模拟出印度夏季风和华北夏季降水的遥相关关系,其相应的环流异常系统与诊断分析结果非常一致,这从另一方面证实了这种遥相关关系的存在和可靠性.  相似文献   

MM5 Simulations of the China Regional Climate During the LGM.Ⅰ: Influence of CO2 and Earth Orbit Change          下载免费PDF全文

LIU yu  HE Jinhai  LI Weiliang  CHEN Longxun   《Acta Meteorologica Sinica》2008,22(1):8-21

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Prediction Research of Climate Change Trends over North China in the Future 30 Years   总被引：1，自引：0，他引：1       下载免费PDF全文

LIU Yanxiang  YAN Jinghui  WU Tongwen  GUO Yufu  CHEN Lihu  WANG Jianping 《Acta Meteorologica Sinica》2008,22(1):42-50

A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 （Global Ocean-Atmosphere-Land system coupled model）, developed by the State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP）, Chinese Academy of Sciences （CAS）. In order to validate the model, the modern climate during 1951-2000 was first simulated by the GOALS model with the actual greenhouse gas concentration, and the simulation results were compared with observed data. The simulation results basically reproduce the lower temperature from the 1960s to mid-1970s and the warming from the 1980s for the globe and Northern Hemisphere, and better the important cold （1950 1976） and warm （1977-2000） periods in the past 50 years over North China. The correlation coefficient is 0.34 between simulations and observations （significant at a more than 0.05 confidence level）. The range of winter temperature departures for North China is between those for the eastern and western China＇s Mainland. Meanwhile, the summer precipitation trend turning around the 1980s is also successfully simulated. The climate change trends in the future 30 years were simulated with the CO2 concentration under IPCC SRES-B2 emission scenario. The results show that, in the future 30 years, winter temperature will keep a warming trend in North China and increase by about 2.5~C relative to climate mean （1960-1990）. Meanwhile, summer precipitation will obviously increase in North China and decrease in South China, displaying a south-deficit-north-excessive pattern of precipitation.  相似文献   

An Assessment on the Performance of IPCC AR4 Climate Models in Simulating Interdecadal Variations of the East Asian Summer Monsoon   总被引：3，自引：0，他引：3       下载免费PDF全文

SUN Ying  DING Yihui 《Acta Meteorologica Sinica》2008,22(4):472-488

Observations from several data centers together with a categorization method are used to evaluate the IPCC AR4 （Intergovernmental Panel on Climate Change, the Fourth Assessment Report） climate models＇ performance in simulating the interdecadal variations of summer precipitation and monsoon circulation in East Asia. Out of 19 models under examination, 9 models can relatively well reproduce the 1979-1999 mean June-July-August （JJA） precipitation in East Asia, but only 3 models （Category-1 models） can capture the interdecadal variation of precipitation in East Asia. These 3 models are： GFDL-CM2.0, MIROC3.2 （hires）, and MIROC3.2 （medres）, among which the GFDL-CM2.0 gives the best performance. The reason for the poor performance of most models in simulating the East Asian summer monsoon interdecadal variation lies in that the key dynamic and thermal-dynamic mechanisms behind the East Asian monsoon change are missed by the models, e.g., the large-scale tropospheric cooling and drying over East Asia. In contrast, the Category-1 models relatively well reproduce the variations in vertical velocity and water vapor over East Asia and thus show a better agreement with observations in simulating the pattern of ＂wet south and dry north＂ in China in the past 20 years.
It is assessed that a single model＇s performance in simulating a particular variable has great impacts on the ensemble results. More realistic outputs can be obtained when the multi-model ensemble is carried out using a suite of well-performing models for a specific variable, rather than using all available models. This indicates that although a multi-model ensemble is in general better than a single model, the best ensemble mean cannot be achieved without looking into each member model＇s performance.  相似文献   

Regional climate change experiments over southern South America. I: present climate   总被引：2，自引：2，他引：0  

Silvina A. Solman  Mario N. Nuñez  María Fernanda Cabré 《Climate Dynamics》2008,30(5):533-552

We present an analysis of a regional simulation of present-day climate (1981–1990) over southern South America. The regional model MM5 was nested within time-slice global atmospheric model experiments conducted by the HadAM3H model. We evaluate the capability of the model in simulating the observed climate with emphasis on low-level circulation patterns and surface variables, such as precipitation and surface air mean, maximum and minimum temperatures. The regional model performance was evaluated in terms of seasonal means, seasonal cycles, interannual variability and extreme events. Overall, the regional model is able to capture the main features of the observed mean surface climate over South America, its seasonal evolution and the regional detail due to topographic forcing. The observed regional patterns of surface air temperatures (mean, maxima and minima) are well reproduced. Biases are mostly within 3°C, temperature being overestimated over central Argentina and underestimated in mountainous regions during all seasons. Biases in northeastern Argentina and southeastern Brazil are positive during austral spring season and negative in other seasons. In general, maximum temperatures are better represented than minimum temperatures. Warm bias is larger during austral summer for maximum temperature and during austral winter for minimum temperature, mainly over central Argentina. The broad spatial pattern of precipitation and its seasonal evolution are well captured; however, the regional model overestimates the precipitation over the Andes region in all seasons and in southern Brazil during summer. Precipitation amounts are underestimated over the La Plata basin from fall to spring. Extremes of precipitation are better reproduced by the regional model compared with the driving model. Interannual variability is well reproduced too, but strongly regulated by boundary conditions, particularly during summer months. Overall, taking into account the quality of the simulation, we can conclude that the regional model is capable in reproducing the main regional patterns and seasonal cycle of surface variables. The present reference simulation constitutes the basis to examine the climate change simulations resulting from the A2 and B2 forcing scenarios which are being reported in a separate study.  相似文献   

Consistency of observed winter precipitation trends in northern Europe with regional climate change projections   总被引：1，自引：0，他引：1  

Jonas Bhend  Hans von Storch 《Climate Dynamics》2008,31(1):17-28

Often it is claimed that the recent changes in northern European climate are at least partly anthropogenic even though a human influence has not yet been successfully detected. Hence we investigate whether the recent changes are consistent with regional climate change projections. Therefore, trends in winter (DJF) mean precipitation in northern Europe are compared to human induced changes as predicted by a set of four regional climate model simulations. The patterns of recent trends and predicted changes match reasonably well as indicated by pattern correlation and the similarity is very likely not random. However, the model projections generally underestimate the recent change in winter precipitation. That is, the signal-to-noise ratio of the anthropogenic precipitation change is either rather low or the presently used simulations are significantly flawed in their ability to project changes into the future. European trends contain large signals related to the North Atlantic Oscillation (NAO), of which a major unknown part may be unrelated to the anthropogenic signal. Therefore, we also examine the consistency of recent and projected changes after subtracting the NAO signal in both the observations and in the projections. It turns out that even after the removal of the NAO signal, the pattern of trends in the observations is similar to those projected by the models. At the same time, the magnitude of the trends is considerably reduced and closer to the magnitude of the change in the projections.  相似文献