2000年冬季阿勒泰区域性大-暴雪成因分析

对形成2000年冬季阿勒泰地区出现的6场区域性大－暴雪天气过程的欧亚大尺度环流与天气尺度影响系统的特征、水汽条件及垂直运动条件等进行综合分析，得出形成阿勒泰区域性大－暴雪天气的重要指标，从而进一步提高阿勒泰区域性大－暴雪天气的预报准确率，对防灾减灾具有重要意义。     

阿山雪灾空前南疆旱象露头

2000年入冬以来，北疆北部的阿勒泰和塔城地区已经出现严重的雪灾。进入 2001年 1月份，该地区又连续遭受北方路径的极地强冷空气活动的侵袭，降水量持续偏多，温度持续偏低，受 1月 5～ 7日寒潮天气的影响，上述各地 1月上旬旬内极端日最低气温竟降至近年来的最低值。同时，阿勒泰本站 1月上旬最大积雪深度达 76cm，突破历史记录，塔城 1月中旬最大积雪深度也达到 59cm，为历史同期第二位。至此，有气象记录以来空前罕见的特大雪灾在北疆北部的阿勒泰和塔城地区酝酿形成，损失极为惨重。而南疆大部地区自 2000年秋季以来至 2001年 1、 2月…     

阿勒泰夏季大降水过程中高潜能场的时空变化特征分析

以大降水过程中触发高潜能量释放的天气系统为背景条件，以高潜能场为起报信息，对40个大降水个例进行统计、分析和归纳，概括出阿勒泰夏季大降水过程中，高潜能场的时空变化特征，从中得出预报阿勒泰夏季大降水的新指标，进一步提高了大降水预报的准确率。     

阿勒泰夏季短期大降水落区的分析和预报

利用１９９８～２０００年６～８月常规高空资料、Ｔ１０６物理量场资料、ＧＭＳ－５卫星云图资料对阿勒泰夏季短期大降水落区的预报进行综合分析,结果表明：把三方面资料结合起来做阿勒泰夏季短期大降水落区预报效果较好。     

低空急流与阿勒泰暖区大--暴雪

分析了冬季产生新疆低空急流的大型环流特征及低空急流与阿勒泰暖区大-暴雪的关系。结果表明，在中高纬度欧亚范围内呈现“双阻型”，中亚中纬度高空维持纬向强急流锋区的情况下，若有巴尔喀什湖以南的暖湿气流向北输送，则有利于造成阿勒泰暖区大-暴雪的新疆低空急流产生。高低空急流的位置及强度可作为降雪量和大-暴雪落区的短期预报指标。     

新疆物候(候鸟)与气候因子关系分析

通过对新疆10个站4种候鸟物候及相应气候因子变化的关系分析,得出候鸟停留时间与同期日照时数及≥0℃的积温关系密切,并经过数理统计,得出用气候因子预测候鸟停留时间的数学模式,对预知一定生态环境中鸟类的迁徙具有一定指导意义。     

集思广益做预报 草原盛开气象花

阿勒泰地域辽阔,地形复杂,气候寒冷,冬季积雪厚,维持时间长,各种灾害性天气频繁,强度大,对当地生产和人民的生活,尤其是对畜牧业生产影响极大.地区发展国民经济的方针是:农林牧副渔综合经营,以牧为主,以农养牧,以牧补农.以畜牧业生产为主是当地国民经济的主要特点.1984年7月胡耀邦总书记视察阿勒泰时指示要把阿勒泰建设成为三个基地,畜牧业就是其     

新疆阿勒泰地区大到暴雪日数气候变化特征

基于新疆阿勒泰地区7个测站1961-2011年逐日降水量,运用线性趋势法、Cubic函数、M—K突变检验、R／S分析、Morlet小波变换法,研究了该地区大到暴雪日数的气候特征。结果表明：该地区大到暴雪日数沿阿尔泰和萨吾尔山脉较多,河谷平原较少,阿勒泰站为大到暴雪高发区,福海站为低发区,11月发生频次最高;各站中,除阿勒泰和福海站变化不显著外,其它站均呈显著增多的趋势;Cubic函数拟合显示：1980年代末到1990年代初大到暴雪日数发生了由少到多的转型,各站在1980年代中期到1990年代初发生了转型,但没有发生突变;Morlet小波分析表明,大到暴雪日数存在着显著的年代际和年际尺度的周期变化;R／S分析表明,在未来该地区大到暴雪日数将逐渐转为减少的趋势,尤其是吉木乃和阿勒泰站。     

阿勒泰山脉对新疆北部地区强暴雪过程影响的数值模拟研究

本文利用中尺度数值模式WRFV3.1对2010年1月6-8日新疆阿勒泰地区的强暴雪过程进行了敏感性数值模拟实验,来研究阿勒泰山脉地形对此次暴雪的影响。结果表明,阿勒泰地形对此次暴雪过程的形成和发展有明显的作用：（1）削减阿勒泰地区地形20%后,在阿勒泰山脉以西会导致降水减少,而在其以东则会导致降水增加;（2）对流层低层垂直速度的分布显示,在此次暴雪过程中,阿勒泰地区存在由于山脉地形引起的地形波,削减地形后会导致山脉地形波的强度减弱;（3）削减阿勒泰地区的地形后,在对流层低层700hPa,会出现气旋式环流增强的特征,而涡度场的表现则比较凌乱,同时也会对水汽场及云微物理量场产生影响。     

阿勒泰地区的降水变化特征

通过对阿勒秦地区近43年来降水资料的分析和研究，得出阿勒秦地区43年来降水变化的规律，并从时空角度揭示出阿勒泰降水量的变化存在区域性。结果表明：从80年代开始降水呈现上升趋势，90年代达最大；降水量的增多主要表现在冬季，其次是秋季和夏季；山麓丘陵、萨吾尔山区是降水量增加趋势较快的地区，平原地区的降水量增加趋势较慢。     

我国近30年龙卷风研究进展

从3方面总结了龙卷风研究成果:①研究概况,最初的龙卷风灾后调查到开展天气气候特征分析至近年来开展龙卷风本体结构、产生机制的探讨,获得了丰硕成果;②研究方法提高,从事实调查到利用统计方法,从利用台站常规观测资料到运用卫星、多普勒雷达、风廓线仪等非常规资料开展分析,近年数值模式WRF、ARPS等也被用来研究龙卷风,研究的方法手段不断得到改进;③龙卷风研究、预报面临的困难和未来展望。     

Trends in Temperature Extremes in Association with Weather-Intraseasonal Fluctuations in Eastern China

Trends in the frequencies of four temperature extremes (the occurrence of warm days, cold days, warm nights and cold nights) with respect to a modulated annual cycle (MAC), and those associated exclusively with weather-intraseasonal fluctuations (WIF) in eastern China were investigated based on an updated homogenized daily maximum and minimum temperature dataset for 1960–2008. The Ensemble Empirical Mode Decomposition (EEMD) method was used to isolate the WIF, MAC, and longer-term components from the temperature series. The annual, winter and summer occurrences of warm (cold) nights were found to have increased (decreased) significantly almost everywhere, while those of warm (cold) days have increased (decreased) in northern China (north of 40°N). However, the four temperature extremes associated exclusively with WIF for winter have decreased almost everywhere, while those for summer have decreased in the north but increased in the south. These characteristics agree with changes in the amplitude of WIF. In particular, winter WIF of maximum temperature tended to weaken almost everywhere, especially in eastern coastal areas (by 10%–20%); summer WIF tended to intensify in southern China by 10%–20%. It is notable that in northern China, the occurrence of warm days has increased, even where that associated with WIF has decreased significantly. This suggests that the recent increasing frequency of warm extremes is due to a considerable rise in the mean temperature level, which surpasses the effect of the weakening weather fluctuations in northern China.     

城市气象研究进展

中国数十年来在城市气象研究这一新兴学科领域开展了大量研究并获得了多方面的丰硕成果。文中从城市气象观测网与观测试验、城市气象多尺度模式、城市气象与大气环境相互影响、城市化对天气气候的影响等4个方面论述了城市气象的主要研究进展:中国各大城市已建立或正在完善具有多平台、多变量、多尺度、多重链接、多功能等特点的城市气象综合观测网;北京、南京、上海等地开展了大型城市气象观测科学试验,被世界气象组织列入研究示范项目;成功开展了风洞实验、缩尺度外场实验研究;建立了多尺度城市气象和空气质量预报数值模式,并应用于业务;在城市热岛效应、城市对降水影响、城市气象与城市规划、城市化对区域气候及空气质量的影响、城市气象与大气环境相互作用等研究领域取得长足进展。最后指出,未来需要重点从新观测技术及观测资料同化应用、城市系统模式研究、城市化对天气气候的影响机理、城市化对大气环境和人体健康的影响、城市水文气象气候与环境综合服务等方面开展科学研究与应用,为中国城市化、生态文明建设、防灾减灾和应对气候变化等国家需求提供科技支撑。      

Recent advances in monsoon studies in China

This review provides a synopsis of the major progress that has been made in monsoon studies in China and to further bridge the gap between the Chinese and international meteorological community. It consists of seven major sections. After the introduction, the second section begins with the global monsoon systems and their seasonal variation, based on some new methods proposed in recent years. Besides, some major intraseasonal features of East Asian monsoon, including the onset of South China Sea summer monsoon are discussed. In the third section, we review the interactions between ENSO and the East Asian monsoon, focusing in particular on the results of Chinese meteorologists that indicate the influence of ENSO on the East Asian summer monsoon(EASM) is obviously different from that on the tropical monsoon. Besides the tropical Pacific,other ocean basins, such as the Indian Ocean and the Atlantic Ocean, are also important to the East Asian monsoon, and this topic is discussed in the fourth section. In the fifth section, we address the role of land surface processes in East Asian monsoon. For example, we describe work that has shown more snow cover in spring on the Tibetan Plateau is followed by a weakened EASM and more summer rainfall in the Yangtze River valleys. The sixth section focuses on the influence of atmospheric circulation in the Southern Hemisphere(SH) on EASM, demonstrating how the signal from the SH is likely to provide new clues for the seasonal forecasting of summer rainfall in China. Finally, in the seventh section, we concentrate on the interdecadal variations of EASM. In particular, we look at a significant interdecadal variation that occurred at the end of the 1970 s, and how our understanding of this feature could affect forecasting ability.     

Changes in polar amplification in response to increasing warming in CMIP6

由于全球变暖,极地地区的气候经历了明显的变暖放大.在本项研究中,我们根据CMIP6模式的三种变暖情景(SSP1-2,6,SSP2-4.5和SSP5-8.5)下,极地放大变化对各个反馈机制(包括普朗克,温度递减率,云,水蒸气,反照率反馈,CO2强迫,海洋热吸收和大气热传输)的响应进行了分析.结果表明,通过用“辐射核”方法...     

1956-2007年河南省降水和水资源变化及评估

利用河南省103个气象站的降水量和各省辖市的水资源资料,分析了河南省1956-2007年降水和水资源变化特点,对降水资源量和水资源量进行了丰枯评估;分别采用线性相关法和产水系数法以降水量估算水资源量,并对估算效果进行了对比分析。结果表明：1) 52年来河南省年降水资源量呈不明显的减少趋势,减少速率为2.32亿m3/10a;省内不同区域降水资源量的变化趋势不太一致,豫北、豫西和豫中为减少趋势,豫东、豫西南和豫南呈不同程度的增加趋势。2) 52年来全省水资源总量呈减少趋势,减少速率为10.85亿m3/10a,大于降水资源量的减少速率,省内各区域水资源量均呈弱减少趋势,减少速率为豫西最大,豫北次之,豫中最少;全省水资源总量的年代际变化特点与降水资源量基本一致。3) 水资源总量与降水量关系密切,用年降水量估算水资源总量,平均相对误差为10%～22%;将线性相关法和产水系数法两种估算模式分别用于不同丰枯程度年景的估算,可减小估算误差。     

Stable isotopic variations in precipitation in Southwest China

This study analyzes the relationships of stable isotopes in precipitation with temperature, air pressure and humidity at different altitudes, and the potential influencing mechanisms of control factors on the stable isotopes in precipitation in Southwest China. There appear marked negative correlations of the δ18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW)at the Mengzi, Simao and Tengchong stations on the synoptic timescale; the marked negative correlations between the δ18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850hPa are different from the temperature effect in middle-high-latitude inland areas. In addition, the notable positive correlation between the δ18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. Precipitation is not the only factor generating an amount effect. Probably,the amount effect is related to the variations of atmospheric circulation and vapor origins. On the annual timescale, the annual precipitation amount weighted-mean δ18O displays negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with an abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in Southwest China and generates abnormally strong rainfall on the way. Meanwhile, the abnormally strong condensation process will release more condensed latent heat in the atmosphere, and this will lead to a rise of atmospheric temperature during rainfall but a decline of δ18O in the precipitation. On the other hand, in the years with an abnormally weak summer monsoon, the precipitation and the atmospheric temperature during rainfalls decrease abnormally but the δ18O in precipitation increases.     

近44年南京温度变化的特征及其可能原因的分析

利用1957～2000年的气候观测资料,研究南京的平均温度、平均最高温度、平均最低温度和平均日较差及炎热日和寒冷日的变化趋势和特点,并分析可能的原因;以滁县和溧阳为对比城市站,分析了三种不同类型城市温度变化的异同.结果表明,近44年来南京平均温度显著上升,其中冬季增暖幅度最大,但夏季呈变凉趋势.与全国平均温度相比,线性变化趋势大体相似,但也存在一定差别.最高温度趋势与平均温度一致,夏季降温更为明显;最低温度除夏季外增暖都非常显著,表明气候变暖在最低温度上表现更加明显;年和各季日较差均明显减小;炎热日和寒冷日趋于减少,其开始和结束时间较以前有明显提前.大气环流系统的变异和调整可能是温度显著升高的直接原因.同样,长江中下游夏季降水天气增多、云量增加、日照时间减少以及伴随的温度下降可能也与环流系统的调整有关.南京与滁县、溧阳的温度差值分别为减小趋势或趋势变化不明显.三种类型城市增暖幅度的相对大小存在着年代际差异.由于不同类型城市间温度变化差异的复杂特点及其所反映出的城市化影响的复杂性,在研究温度变化和考虑城市化的影响时,不仅要考虑大城市,还应该充分注意中、小城市的发展所带来的影响.     

Progress in Semi-arid Climate Change Studies in China

This article reviews recent progress in semi-arid climate change research in China.Results indicate that the areas of semiarid regions have increased rapidly during recent years in China,with an increase of 33%during 1994-2008 compared to 1948-62.Studies have found that the expansion rate of semi-arid areas over China is nearly 10 times higher than that of arid and sub-humid areas,and is mainly transformed from sub-humid/humid regions.Meanwhile,the greatest warming during the past 100 years has been observed over semi-arid regions in China,and mainly induced by radiatively forced processes.The intensity of the regional temperature response over semi-arid regions has been amplified by land-atmosphere interactions and human activities.The decadal climate variation in semi-arid regions is modulated by oceanic oscillations,which induce land-sea and north-south thermal contrasts and affect the intensities of westerlies,planetary waves and blocking frequencies.In addition,the drier climates in semi-arid regions across China are also associated with the weakened East Asian summer monsoon in recent years.Moreover,dust aerosols in semi-arid regions may have altered precipitation by affecting the local energy and hydrological cycles.Finally,semi-arid regions in China are projected to continuously expand in the 21st century,which will increase the risk of desertification in the near future.     

Characteristics of Chemical Speciation in PM_1 in Six Representative Regions in China

A better knowledge of aerosol properties is of great significance for elucidating the complex mechanisms behind frequently occurring haze pollution events. In this study, we examine the temporal and spatial variations in both PM_1 and its major chemical constituents using three-year field measurements that were collected in six representative regions in China between 2012 and 2014. Our results show that both PM_1 and its chemical compositions varied significantly in space and time, with high PM_1 loadings mainly observed in the winter. By comparing chemical constituents between clean and polluted episodes, we find that the elevated PM_1 mass concentration during pollution events should be largely attributable to significant increases in organic matter(OM) and inorganic aerosols like sulfate, nitrate, and ammonium(SNA),indicative of the critical role of primary emissions and secondary aerosols in elevating PM_1 pollution levels. The ratios of PM_1/PM_(2.5) are found to be generally high in Shanghai and Guangzhou, while relatively low ratios are seen in Xi'an and Chengdu, indicating anthropogenic emissions were more likely to accumulate in forms of finer particles. With respect to the relative importance of chemical components and meteorological factors quantified via statistical modeling practices, we find that primary emissions and secondary aerosols were the two leading factors contributing to PM_1 variations, though meteorological factors also played important roles in regulating the dispersion of atmospheric PM.