ADVANCES IN REGIONAL CLIMATE MODELING SINCE 1990

Due to the close relationship between regional climate anomalies and social-economy andsociety development,climatologists worldwide paid great attention to the regional climateanomalies over a long period of time and the corresponding investigation of regional climatemodeling has made great progresses.Since 1990 the regional climate simulations have made a moresubstantial achievement.This paper will focus on the reliability and uncertainties of regionalclimate modeling by global climate models,the advances on regional climate modeling in the worldand the outlook of regional climate modeling.     

CHARACTERISTICS OF CLIMATE WARMING AND IMPACT ON CLIMATE ZONES CHANGE IN GUANGDONG

Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature warms by 0.16 °C/10a in Guangdong. The range of warming was lower than the average of nationwide and global land surface. Furthermore, the temperature has a larger increase tendency in winter and spring and coastal areas than in summer and autumn and inland areas. Climate zones move towards the north obviously. North tropical zone is expanding, south subtropical zone is reducing and central subtropical zone is relatively stable. Under the global climate warming, characteristics of climate warming in Guangdong were influenced by atmosphere general circulation, sea surface temperature and human activities etc.     

广东气候变暖若干特征及其对气候带变化的影响

对广东省近50年的气温资料统计结果表明,广东省陆面气温增暖率为0．16℃／10年,低于全国和全球陆面增暖率;气候变暖的时空特征表现为冬季和春季明显大于夏季和秋季,沿海地区明显大于内陆地区,气候带向北移动的趋向明显,北热带区域面积在扩大,南亚热带区域面积在缩小,中亚热带区面积相对稳定。分析认为,在全球气候变暖的背景下,广东气候变暖具有地方性特征,主要是受大气环流、海温和人类活动等方面的综合影响。     

中国近代土地利用变化对区域气候影响的数值模拟

利用国家气候中心改进的高分辨率区域气候模式(RegCM-NCC)模拟研究了中国近代历史时期土地利用/覆盖变化对中国区域气候的影响,模拟结果显示,1700年以来,以森林砍伐、草地退化及相应耕地面积扩大为主的土地利用变化可能对中国区域降水、温度产生了显著影响。1700—1900年期间,由于土地利用的变化使华北、西南等地区降水呈减少趋势,其他区域变化不明显,但近50年来却使长江中下游地区、西北、东北部分地区降水有所增加。1700—1800年间的土地利用变化使得除东北及长江流域地区外的大部分地区温度呈下降趋势,1900年以后有所升高,特别是近50年来中国大部分区域平均气温升高,与这一时期由于大气中温室气体排放浓度增加造成的温度升高相一致。另外,土地利用变化不仅使大气温度、湿度发生变化,还可引起基本流场的变化,使东亚冬、夏季风气流有所增强,这主要是由于植被变化改变了地面温度,使海、陆温差进一步增大的结果。因此,土地利用变化对区域尺度气候变化的影响是不容忽视的。     

AN ANALYSIS OF THE WINTER EXTREME PRECIPITATION EVENTS ON THE BACKGROUND OF CLIMATE WARMING IN SOUTHERN CHINA

Based on daily precipitation and monthly temperature data in southern China, the winter extreme precipitation changes in southern China have been investigated by using the Mann-Kendall test and the return values of Generalized Pareto Distribution. The results show that a winter climate catastrophe in southern China occurred around 1991, and the intensity of winter extreme precipitation was strengthened after climate warming. The anomalous circulation characteristics before and after the climate warming was further analyzed by using the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. It is found that the tropical winter monsoon over East Asia is negatively correlated with the precipitation in southeastern China. After climate warming the meridionality of the circulations in middle and high latitudes increases, which is favorable for the southward movement of the cold air from the north. In addition, the increase of the temperature over southern China may lead to the decrease of the differential heating between the continent and the ocean. Consequently, the tropical winter monsoon over East Asia is weakened, which is favorable for the transport of the warm and humid air to southeastern China and the formation of the anomalous convergence of the moisture flux, resulting in large precipitation over southeastern China. As a result, the interaction between the anomalous circulations in the middle and high latitudes and lower latitudes after the climate warming plays a major role in the increase of the winter precipitation intensity over southeastern China.     

CLIMATE WARMING IN GUANGDONG PROVINCE AND ITS INFLUENCES ON AGRICULTURE AND COUNTER MEASURES

Climate changes in Guangdong are studied based on temperature data of 86 meteorological stations in Guangdong Province during 1961 – 2000, temperature data in Guangzhou during 1908 – 2002, and sea level data in the South China Sea during 1958 – 2001.…     

气候变暖对中国水稻生产可能影响的研究

利用随机天气模型,将大气环流模式预测的气候情景与水稻模式相链接,研究了气候变暖对中国水稻生产的可能影响。结果表明,大气中ＣＯ２浓度加倍,中国水稻主产区适宜水稻生长的日数将延长６～１１ｄ,积温增加２２０～３３０℃·ｄ。积温的相对增长率由南向北呈增长趋势。水稻产量形成期低温天气出现频率将减少,而高温天气出现的频率增加。若品种与播种、移栽期不变,水稻产量将下降;而若通过改变品种使作物生育期基本保持目前的状况,减产幅度将比品种不变时明显偏小,部分地区还有可能增产。     

CLIMATE CHANGE AND NATURAL VEGETATION IN CHINA

The climate change scenarios due to the human activity for East Asia and China by 2050 have been estimated bymeans of a simple global social-economic-climate-impact model combined with seven GCMs.The climate change sce-narios present that the annual mean temperature might increase obviously,by about 1.4℃,and the annual total precipi-tation might increase by about 4% in whole China in comparison with the present climate.The change of the precipita-tion might be much smaller than that of the temperature.The potential impacts of human activity-induced climate change on natural vegetation in China were estimated us-ing the vegetation-climate model developed specially for Chinese vegetation types and different climate change scenariosderived from seven GCMs for 2050.All scenarios suggest a great change in natural vegetation although details of pre-dicted types vary among the scenarios.There will be a northward shift of the vegetation types,with increase in the arealextent of tropical rainforests and decrease of the cold temperate coniferous forest and tundra.Consequently,consideringthese changes and shifts,especially in combination with the likely negative balance of precipitation andevapotranspiration,the moisture stress,i.e.,less water availability arises,the possible influences of climate change onChinese agriculture is also assessed roughly in this paper.     

广东地区的气候变暖及其对农业的影响与对策

根据广东省86个站1961～2000年气温资料、广州市1908～2002年气温资料以及1958～2001年南海海平面资料,论证了广东省气候变暖的明显趋势;从热量资源、作物和品种布局、作物产量、病虫草害、农业气象灾害等方面论述了气候变暖对广东农业的可能影响,并提出了防范和适应气候变暖的农业对策.     

北半球增暖对我国气侯的影响

本文在分析100多年来北半球平均气温长期变化基本特征的基础上,讨论了北半球气温变化对我国气候变化的影响。结果表明,我国大范围气温距平与北半球平均气温有显著的正相关,长江中下游和华北平原的温度距平值平均为北半球平均气温距平的1.4-1.6倍。还表明,我国降水距平分布与北半球气温变化也有一定的联系。在北半球平均气温偏高和偏低年份,欧亚地区500hPa环流特征的差异是显著的。这表明,我国大范围气候距平与北半球平均气温距平的统计相关是有一定的物理基础的。     

IMPACT OF SUMMER WARMING ON DYNAMICS-STATISTICS-COMBINED METHOD TO PREDICT THE SUMMER TEMPERATURE IN CHINA

Based on NCEP/NCAR daily reanalysis data, climate trend rate and other methods are used to quantitatively analyze the change trend of China's summer observed temperature in 1983—2012. Moreover, a dynamics-statistics-combined seasonal forecast method with optimal multi-factor portfolio is applied to analyze the impact of this trend on summer temperature forecast. The results show that: in the three decades, the summer temperature shows a clear upward trend under the condition of global warming, especially over South China, East China, Northeast China and Xinjiang Region, and the trend rate of national average summer temperature was 0.27℃ per decade. However, it is found that the current business model forecast(Coupled Global Climate Model) of National Climate Centre is unable to forecast summer warming trends in China, so that the post-processing forecast effect of dynamics-statistics-combined method is relatively poor. In this study, observed temperatures are processed first by removing linear fitting trend, and then adding it after forecast to offset the deficiency of model forecast indirectly. After test, ACC average value in the latest decade was 0.44 through dynamics-statistics-combined independent sample return forecast. The temporal correlation(TCC) between forecast and observed temperature was significantly improved compared with direct forecast results in most regions, and effectively improved the skill of the dynamics-statistics-combined forecast method in seasonal temperature forecast.     

THE IMPACT OF CLIMATE CHANGE ON WATER DEFICIT AND PRODUCTION OF WINTER WHEAT IN NORTH CHINA

The water deficits in different development stages and the whole growing season of winterwheat in North China under climate change scenarios are analyzed based on the meteorological da-ta,crop phenomenon and soil hydrological data of 30 weather stations.The results show that ifthe temperature rises,the potential evapotranspiration and crop maximum transpiration will in-crease 8%-10%;the actual evapotranspiration in whole growing season will increase about 1%-2%;and it seems to decrease in spring.Therefore the water deficit status would deteriorate.Theamount of water deficit in whole growing season would increase 14%-30%,and the water deficitisolines might shift southward with maximum shift distance being 190 km.As a result the climaticsuitability of winter wheat would change,and the variation rate of yield reduction will be 8%-20% of the present value which results in the declining output values.The irrigation amountwould increase 25%-33%,and the agriculture cost might increase owing to additional irrigation.     

北京气候变暖与主要极端气温指数的归因分析

在对资料进行均一化处理的基础上,分析了北京1960—2008 年气候变暖及主要极端气温指数的统计特征,并应用格兰杰检验法对其进行归因分析。结果表明:(1) 近49 a 来北京年平均气温增速约为0.39 ℃/(10 a),气候增暖具有明显的非对称性。(2) 霜冻指数和气温年较差呈下降趋势,降幅为3.9 d/(10 a)和0.8 ℃/(10 a)。生长季指数、暖夜指数及热浪指数则呈上升趋势,增幅平均达3.0 d/(10 a)、0.75%/(10 a)和1.5 d/(10 a)。(3) 北京年平均气温是霜冻指数、生长季指数及暖夜指数发生变化的格兰杰原因。虽然年平均气温与热浪指数在不同滞后期均具强相关性,但是检验表明它们之间并无显著的因果关系,很可能是由于某种原因导致的一种统计上的伪相关现象。      

我国南方冬季气候变暖前后极端降水事件分析

利用我国南方逐日降水资料及逐月温度资料,采用Mann-Kendall突变检验方法,并计算极端降水的GPD(Generalized Pareto Distribution)重现值,讨论了气候变暖前后我国南方冬季极端降水事件的变化。结果表明,我国南方冬季气候变暖的突变发生在1991年前后,且气候变暖后我国南方冬季的极端降水强度普遍有所增加。利用NCEP/NCAR再分析资料进一步分析气候变暖前后的环流场特征,发现东亚热带冬季风异常与我国华南、江南地区降水异常有显著的相关关系。东亚热带冬季风偏强(弱),华南、江南地区降水偏少(多)。气候变暖后中高纬度环流经向度加大,有利于北方的冷空气向南输送。此外,气候变暖后我国南方地面气温升高,海陆热力差异减小,东亚热带冬季风减弱,有利于西太平洋的暖湿气流向我国大陆东南部输送,并在东南部形成异常的水汽通量辐合,有利于形成强降水。气候变暖后,中高纬度与中低纬度异常环流系统的相互作用是我国东南部降水强度增加的主要原因。     

ONSET AND RETREAT DATES OF THE SOUTH CHINA SEA SUMMER MONSOON AND THEIR RELATIONSHIPS WITH THE MONSOON INTENSITY IN THE CONTEXT OF CLIMATE WARMING

Global gridded daily mean data from the NCEP/NCAR Reanalysis(1948-2012) are used to obtain the onset date,retreat date and duration time series of the South China Sea summer monsoon(SCSSM) for the past 65 years.The summer monsoon onset(retreat) date is defined as the time when the mean zonal wind at 850 hPa shifts steadily from easterly(westerly) to westerly(easterly) and the pseudo-equivalent potential temperature at the same level remains steady at greater than 335 K(less than 335 K) in the South China Sea area[110-120°E(10-20°N)].The clockwise vortex of the equatorial Indian Ocean region,together with the cross-equatorial flow and the subtropical high,plays a decisive role in the burst of the SCSSM.The onset date of the SCSSM is closely related to its intensity.With late(early) onset of the summer monsoon,its intensity is relatively strong(weak),and the zonal wind undergoes an early(late) abrupt change in the upper troposphere.Climate warming significantly affects the onset and retreat dates of the SCSSM and its intensity.With climate warming,the number of early-onset(-retreat) years of the SCSSM is clearly greater(less),and the SCSSM is clearly weakened.     

ADVANCES IN APPLIED RESEARCH OF THE OUTGOING LONGWAVE RADIATION IN CHINA

The outgoing longwave radiation(OLR)observed by NOAA satellite series has widely applied in various researchfields since the 1980s in China.In this paper,advances of the applied research of OLR are described in the following re-spects:(1)Studies of the global ITCZ;(2)Climatology of the subtropical high over northern Pacific;(3)Studies of the tropical cyclone over West Pacific;(4)Characteristics of the intraseasonal variation(ISV)of tropical convective activities;(5)Divergence wind and large scale circulation over the tropics;(6)Studies of the air-sea interaction;(7)Estimation of precipitation over the Tibetan Plateau and the Yangtze River(Changjiang River)basin during therainy season;(8)Analyses of regional climates of China;(9)Studies of prediction of the severe and disastrous weather and climate;(10)Atlas of OLR.The distinctive features of these advances are reviewed and the focal points of the OLR applied research in futureare also suggested.     

我国能源消费结构变化与气候特征

文章利用多项式法将气候耗能量从能源消费总量中分离出来，用统计分析的方法探讨了气候耗能量与气候因子之间的关系及其变化。研究表明：从20世纪50年代到80年代初期，旱涝灾害是影响我国气候耗能量的主要气候因子，它们之间存在显著的线性相关关系，随着经济的发展和人民生活水平的提高，旱涝灾害对气候耗能量的影响逐渐减弱，气温对气候耗能量的影响日趋显著，目前正处于过渡时期。     

IMPACTS OF CLIMATE CHANGE ON CROPPING SYSTEM AND ITS IMPLICATION FOR AGRICULTURE IN CHINA

Based on the analyses on amplitudes of historical variation of temperature and precipitation inthe past 500 years and latest 100 years,according to the regional climate change scenarios forChina estimated by composite GCM,the potential impacts of climate change on cropping systemsin China in future are simulated and assessed using the cropping system model developmentspecially for the Chinese cropping patterns.It is shown that under the projected future climatechange by 2050 the most parts of the present double cropping area would be replaced by thedifferent triple cropping patterns while the current double cropping area would shift towards thecentral part of the present single cropping area.More explicitly,the northern boundary of triplecropping area would shift from its current border at the Changjing River to the Huanghe River,ashift of more than 5 degrees of latitude.And the shift of multiple cropping areas leads to asignificant decrease of single cropping area.Furthermore,considering the changes mentioned above in combination with the likely negativebalance of precipitation and evapotranspiration and,therefore,increase of moisture stress(i.e.less water availability),as well as the possible increase of heat stress disaster and decrease of LGS(length of growing season),the potential implication of climate change for agriculture in China arealso analyzed roughly in this paper.As a result,however,it is still very difficult to reach a specific conclusion that the futureclimate change will he favorable or unfavorable to farm in China because of the complicated Chinesefarming patterns,the complex-various social and economic environment of agriculturaldevelopment and,especially,a great scientific uncertainties in the investigation/prediction ofclimate change.     

华南热带气旋影响时段的短期气候集成预测

利用华南沿海代表站逐日历史资料和南海附近区域再分析格点资料,采用灰色拓扑预测、天文周期、阴阳历叠加等方法,建立非线性综合集成预测模型,对上述站点和区域的逐日气压、降水量等要素进行气候预测;通过分析沿海各代表站气压谷值、降水峰值的出现时间、以及南海区域气压场中低压环流的位置和动态,综合确定年内影响华南的热带气旋可能出现的时间段和区域。该方法在广东省气象台投入业务应用多年,经检验近5年(7—9月台风活跃季节)热带气旋影响时段的平均预测准确率达到70%左右。     

DECADAL VARIABILITY OF SUBSURFACE OCEAN TEMPERATURE ANOMALY IN TROPICAL PACIFIC AND ITS IMPACT ON CLIMATE OF CHINA

In this study,we investigate the decadal variability of subsurface ocean temperature anomaly(SOTA)in the tropical Pacific and associated anomalous atmospheric circulation over Asia-North Pacific-North America by analyzing 50 years of atmosphere-ocean data from the National Center for Environmental Prediction(NCEP)reanalysis project and Simple Ocean Data Assimilation(SODA).Relationship between the ENSO-Like variability and climate of China is also revealed.The results show that the decadal variability of tropical Pacific SOTA has two dominant ENSO-like modes:the primary mode is an ENSO-Like mature phase pattern,and the second mode is associated with the ENSO-like transition(developing or decaying)phase.These two modes consist of a cycle of ENSO-Like variability,which exhibits a quasi-40a fluctuation,superimposed with an oscillation of a 13a period.The ENSO-Like variability in the tropical Pacific influences the atmosphere system at the mid-and higher-latitudes and subtropical regions,resulting in decadal variability of south wind over North China,the East Asian monsoon and climate of China.During the mature phase of El Ni o-Like variability,the anomalous north wind prevails over the north part of China and the East Asian monsoon weakens,with little rain in North China but much rain in the middle-and lower-reaches of the Yangtze River.With El Ni o-Like decaying(La Ni a-Like developing),anomalous northerly wind also prevails over North China,then the East Asian monsoon weakens with drought occurring in North China.The situation during the La Ni a-Like variability is the opposite.The pattern of anomalous climate of China is primarily dominated by the first ENSO-like variability,while the second mode can modulate the contribution of the first one,depending on whether its phase agrees with that of the first mode.The climate shift in China around 1978 and successive occurrence of drought for more than 20 years in North China are primarily induced by the first two ENSO-like variabilities.The latest La Ni a-Like phase starts from 1998 and will presumably end around 2018.It is expected that more rainfall would be in North China and less rainfall would appear in the middle-and lower-reaches of the Yangtze River valley during this period.