Detection, Causes and Projection of Climate Change over China： An Overview of Recent Progress

This article summarizes the main results and findings of studies conducted by Chinese scientists in the past five years.It is shown that observed climate change in China bears a strong similarity with the global average.The country-averaged annual mean surface air temperature has increased by 1.1℃over the past 50 years and 0.5-0.8℃over the past 100 years,slightly higher than the global temperature increase for the same periods.Northern China and winter have experienced the greatest increases in surface air temperature.Although no significant trend has been found in country-averaged annual precipitation, interdecadal variability and obvious trends on regional scales are detectable,with northwestern China and the mid and lower Yangtze River basin having undergone an obvious increase,and North China a severe drought.Some analyses show that frequency and magnitude of extreme weather and climate events have also undergone significant changes in the past 50 years or so. Studies of the causes of regional climate change through the use of climate models and consideration of various forcings,show that the warming of the last 50 years could possibly be attributed to an increased atmospheric concentration of greenhouse gases,while the temperature change of the first half of the 20th century may be due to solar activity,volcanic eruptions and sea surface temperature change.A significant decline in sunshine duration and solar radiation at the surface in eastern China has been attributed to the increased emission of pollutants. Projections of future climate by models of the NCC(National Climate Center,China Meteorological Administration)and the IAP(Institute of Atmospheric Physics,Chinese Academy of Sciences),as well as 40 models developed overseas,indicate a potential significant warming in China in the 21st century,with the largest warming set to occur in winter months and in northern China.Under varied emission scenarios,the country-averaged annual mean temperature is projected to increase by 1.5-2.1℃by 2020,2.3-3.3℃by 2050, and by 3.9-6.0℃by 2100,in comparison to the 30-year average of 1961 1990.Most models project a 10% 12% increase in annual precipitation in China by 2100,with the trend being particularly evident in Northeast and Northwest China,but with parts of central China probably undergoing a drying trend.Large uncertainty exists in the projection of precipitation,and further studies are needed.Furthermore,anthropogenic climate change will probably lead to a weaker winter monsoon and a stronger summer monsoon in eastern Asia.     

植被对环境气候影响的数值模拟研究思路综述

介绍了用数值模拟方法研究植被对环境气候影响的基本思路。气候模式中植被作用的模拟思路分为考虑植被的物理特性、生物过程和化学过程三类，按照三类过程分别介绍了国内外有关数值试验的进展及主要结论，评论了各类研究思路的不足和局限，提出今后可能改进的方向。     

Chinese Contribution to CMIP5：An Overview of Five Chinese Models’Performances

An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 （CMIP5） is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 pro ject are assessed in the context of climate mean states, seasonal cycle, intraseasonal oscillation, interan-nual variability, interdecadal variability, global monsoon, Asian-Australian monsoon, 20th-century historical climate simulation, climate change pro jection, and climate sensitivity. Both the strengths and weaknesses of the models are evaluated. The models generally show reasonable performances in simulating sea surface tem-perature （SST） mean state, seasonal cycle, spatial patterns of Madden-Julian oscillation （MJO） amplitude and tropical cyclone Genesis Potential Index （GPI）, global monsoon precipitation pattern, El Ni-no-Southern Oscillation （ENSO）, and Pacific Decadal Oscillation （PDO） related SST anomalies. However, the perfor-mances of the models in simulating the time periods, amplitude, and phase locking of ENSO, PDO time periods, GPI magnitude, MJO propagation, magnitude of SST seasonal cycle, northwestern Pacific mon-soon and North American monsoon domains, as well as the skill of large-scale Asian monsoon precipitation need to be improved. The model performances in simulating the time evolution and spatial pattern of the 20th-century global warming and the future change under representative concentration pathways pro jection are compared to the multimodel ensemble of CMIP5 models. The model discrepancies in terms of climate sensitivity are also discussed.     

A Numerical Simulation Study of Impacts of Historical Land-Use Changes on the Regional Climate in China Since 1700

By using the improved regional climate model (BCC_RegCM1.0), a series of modeling experiments are undertaken to investigate the impacts of historical land-use changes (LUCs) on the regional climate in China. Simulations are conducted for 2 years using estimated land-use for 1700, 1800, 1900, 1950, and 1990. The conversion of land cover in these periods was extensive over China, where large areas were altered from forests to either grass or crops, or from grasslands to crops. Results show that, since 1700, historical LUCs have significant effects on regional climate change, with rainfall increasing in the middle and lower reaches of the Yangtze River Basin, Northwest China, and Northeast China, but decreasing by different degrees in other regions. The air temperature shows significant warming over large areas in recent hundred years, especially from 1950 to 1990, which is consistent with the warming caused by increasing greenhouse gases. On the other hand, historical LUCs have obvious effects on mean circulation, with the East Asian winter and summer monsoonal flows becoming more intensive, which is mainly attributed to the amplifled temperature difference between ocean and land due to vegetation change. Thus, it would be given more attention to the impacts of LUCs on regional climate change.     

Application and Study of Precipitation Schemes in Weather Simulation in Summer and Winter over China

Through simulation of summer and winter precipitation cases in China, the cloud precipitation schemes of model were examined. Results indicate that it is discrepant between convective precipitation simulated by the Kain-Fritsch (KF) scheme and Betts-Miller (BM) scheme in summer, the former scheme is better than the latter in this case. The ambient atmosphere may be varied by different convective schemes. The air is wetter and the updraft is stronger in the KF scheme than in the BM scheme, which can induce the more grid scale precipitation in the KF scheme, i.e., the different cumulus schemes may have the different and important effect on the grid scale precipitation. However, there is almost no convective rain in winter in northern China, so the effect of cumulus precipitation on the grid scale precipitation can be disregarded. Therefore, the gird scale precipitation is primary in the winter of northern China.     

Atmospheric Environmental Capacity of SO2 in Winter over Lanzhou in China： A Case Study

The total emission control method based on atmospheric environmental capacity is the most effective in air pollution mitigation. The atmospheric environmental capacities of SO2 on representative days over Lanzhou are estimated using the numerical models RAMS, HYPACT and a linear programming model, according to the national ambient air quality standard of China （NAAQSCHN）. The results show that the fields of meteorological elements and SO2 simulated by the models agree reasonably well with observations. The atmospheric environmental capacity of SO2 over Lanzhou is around 111.7 × 10^3 kg d^-1, and in order to meet the air quality level Ⅱ of the NAAQSCHN, SO2 emissions need to be reduced by 20%.     

Land-Air Interaction over Arid/Semi-arid Areas in China and Its Impact on the East Asian Summer Monsoon. Part I： Calibration of the Land Surface Model （BATS） Using Multicriteria Methods

To improve the land surface simulation in the arid and semi-arid areas of northern China, the observational data from two field experiments in Dunhuang and Tongyu are used to optimize the parameters in the land surface model, BATS, through calibration with the multicriteria method. Sensitivity analysis to the parameters in Dunhuang and Tongyu indicates that different parameters need to be calibrated in two sites with different environmental and climate regimes. Comparison of observed sensible heat flux, latent heat flux, and ground surface temperature with the simulated ones shows the simulations with the optimized parameters have been substantially improved. Especially, the holistic simulations with the calibration of the parameter values are much closer to the observations in the arid region (Dunhuang), and the energy partition with the calibrated parameters can also be simulated well in the semi-arid region (Tongyu). Whole results demonstrate that the parameter calibration of the land surface model is important when the model is to be used to investigate the land-air interaction.     

大气遥感与卫星气象学研究的进展与回顾

大气遥感作为大气科学中的重要基础与技术支柱,是20世纪60年代以来迅速发展的一门年轻学科.中国大气科学工作者在这方面也紧密结合国家需求与国际学术前沿,从20世纪60年代开始在理论研究,技术发展与实验研究,以及在气象、环境和国防应用等多方面开展了活跃的研究与发展工作.作者主要对中国科学界在大气遥感与卫星气象学发展方面作简要回顾,并着重介绍中国科学院大气物理研究所在大气遥感的基础与方法研究方面的一些进展,以及对大气遥感发展中的作用.主要内容包括:中国大气遥感的简要发展过程、卫星气象的早期发展、卫星红外遥感的基     

基于MODIS多通道资料的白天雾监测

根据云雾微物理性质的差别,用SBDART辐射传输模式模拟了MODIS通道1、6、20、31的云雾光谱辐射特性。模拟结果表明,这4个通道的辐射值中都包含有云雾的信息,能体现出云雾的微物理性质差异,可以用来区分中高云、雾和无云地表,从而实现白天雾的监测。在模拟分析的基础上提出一种白天雾监测的方案,并进行了实例分析。实例分析结果表明,这种多通道雾监测方法提高了白天卫星识别低云和大雾的能力。     

上海一次连续大雾过程的成因分析

利用上海市遥测能见度数据、常规气象资料和T213、GFS分析资料以及GPS-PWV资料,分析了2008年1月5-11日发生在上海地区的一次连续大雾天气过程.分析表明当有天气尺度西风槽频繁活动、槽前暖湿气流不断向气层输入暖湿空气,如再遇特定暖水面或暖海面从近地面向气层输送暖湿气流时,在晴天和微风的早晨极易形成辐射雾;当东、黄海暖湿空气从近地面流向冷水面或冷陆面,如再遇江南低空偏南暖湿气流辐合聚积时,极易形成平流雾.雾区登陆距离与东风气流强弱有关,东风气流越强,雾区西进距离越长.在平流雾期间,0～300 m平均相对湿度的高湿区与雾区吻合.当绝对湿度小于3 g/kg时不会有大雾发生,绝对湿度在9～1 5 g/kg和GPS-PWV值在15 mm左右时,在合适的大气条件下容易形成大雾.     

广西沿海地区大范围雾气候特征与天气形势分析

利用广西沿海地区7站多年的雾日、雾发生时间、雾维持时间及地面观测资料,统计分析该地区雾的气候特征。结果表明,该地区雾地理分布极不均匀;在多年雾日变化上,北海、防城和防港3站呈上升趋势,另4站则呈下降趋势;月际变化明显,12月至次年4月是雾的高发期;雾多发于6至12时且绝大部分雾的维持时间都在1h以上;雾最小能见度低至30m;总结了产生该地区大范围雾的五种天气形势,供短期预报参考。     

EOS—MODIS卫星资料在北疆大雾监测中的应用分析

根据雾与云、积雪、裸地等地表物在可见光、长波红外和中红外波段的反射及辐射特性差异,利用MODIS卫星多通道多光谱探测数据,采用最佳波段组合法和量化判识指标法,对2006年3月8日到10日北疆大雾天气进行判识检验试验和动态监测分析。结果:发现较利于雾与背景(地物、云、雪)分离的最佳波段是可见光B0.65μm和近红外B0.85μm、短红外B1.64μm、中红外B3.7μm、热红外B11μm,综合判识就可以将云、雾、雪、裸地有效的区分;雾在夜间的有效温度在中红外波段比热红外波段低,可采用中红外和热红外波段的组合方法,根据两通道的亮温差进行雾的监测。     

华南霾日和雾日的气候特征及变化

利用华南192个测站1961-2008年的地面气象观测资料,采用线性趋势分析、Mann-Kendall检验、计算气候趋势系数等统计诊断方法,分析了华南年霾日、雾日的时空特征和变化.结果表明:珠江三角洲、广东西北部和广西东北部为多霾区,海南为极少霾区;华南有三个多雾区,分别位于海南中西部地区,两广的西北部地区.两广雾日呈...     

1960—2009年石河子垦区雾天气气候特征及与气象条件的关系分析

利用1960-2009年石河子垦区3个国家级气象站的气象资料,分析大雾天气的气候变化特征。结果表明：石河子垦区年均雾日空间分布特征明显,西北多,东南少,时间分布极不均匀,石河子站雾日呈逐渐减少型,莫索湾站和炮台站呈逐步增多型;石河子垦区雾日在全年的分布状况是春季最多,冬季次之,秋季最少;大雾的逐月变化呈显著季节性特征,集中出现在10-3月,而4-9月,基本无发生;下半夜至翌日上午较易出现大雾,起雾时间为00：00-13：00,其中10：00-12：00最易起雾,雾消时间为14：00-23：00,16：00-22：00雾最易消散;温度在-10～-20℃、相对湿度在91%～100%、风速0～2m/s、风向偏东风和偏南风下石河子雾最易发生。雾天气气候特征及气象条件的分析是预报其发生时间和地点的基础,充分认识其特征和规律是提高雾天预报准确率的前提。     

秦皇岛地区雾天气气候特征及预报

随着交通线路的快速发展,雾对交通运输的影响越来越大,浓雾天气常常引发交通事故,给人民的生命财产造成严重损失,危害性极大.应用秦皇岛1957-2006年气表-1资料,统计分析秦皇岛内陆、沿海地区雾天气时空分布特征,返查1981-2000年历史天气图,得出本地区出现雾的主要天气类型,筛选出影响雾的主要天气要素,建立MOS预报方程,为雾预报及临近预警信号的发布、解除提供有利依据,达到监测、预报之目的.     

中国不同等级雾日的气候特征

利用1961-2005年中国300个台站的逐日雾资料及能见度资料,分析了不同等级雾的时空分布及基本气候特征、雾生时间和持续时间的年代际变化。结果表明：雾的空间分布范围随着能见度的降低而减小;随时间的变化多呈减少趋势,但沿长江及东部沿海的重浓雾日在20世纪70年代发生突变,雾日增多;内陆、南部沿海雾生时间多在清晨06:00-08:00,东部及沿海多发生在夜间20:00-21:00;雾生频次经历少-多-少的年代际变化,90年代后频次减少,个别区域雾生时间随着年代的延伸而推后;大部分地区雾的持续时间在3 h内,12 h以上的雾区多集中在沿海、华北和陇东-山西地区,沿海、四川盆地、云贵地区90年代12 h以上雾的发生频次最高。     

中国不同等级雾日的气候特征

 利用1961-2005年中国300个台站的逐日雾资料及能见度资料,分析了不同等级雾的时空分布及基本气候特征、雾生时间和持续时间的年代际变化。结果表明：雾的空间分布范围随着能见度的降低而减小;随时间的变化多呈减少趋势,但沿长江及东部沿海的重浓雾日在20世纪70年代发生突变,雾日增多;内陆、南部沿海雾生时间多在清晨06:00-08:00,东部及沿海多发生在夜间20:00-21:00;雾生频次经历少-多-少的年代际变化,90年代后频次减少,个别区域雾生时间随着年代的延伸而推后;大部分地区雾的持续时间在3 h内,12 h以上的雾区多集中在沿海、华北和陇东-山西地区,沿海、四川盆地、云贵地区90年代12 h以上雾的发生频次最高。