拉萨一次浮尘天气过程分析

2007年1月15—17日拉萨地区出现了一次浮尘天气,造成空气质量污染,能见度下降;拉萨地区的生产、生活及交通运输受到了较大影响。应用欧洲中心客观分析场资料和逐日观测资料,主要从天气形势和气候特征分析了拉萨浮尘天气形成的原因和空气污染的局地气象条件。结果表明,由于冷暖空气在高原地区对峙,温度梯度和锋区加强;以及200hPa高空西风急流的影响,引发西藏地区大风,使干燥、疏松的地表形成扬沙、沙尘暴,大量的细小沙尘粒子随高空偏西气流携带至拉萨。加之拉萨本地低空处于弱辐合区,大气层结稳定,风速较小或静风,导致了拉萨浮尘天气形成。最后,给出了拉萨浮尘天气预报的思路,为拉萨浮尘天气的准确预报提供了一些参考信息。     

北京地区沙尘天气气溶胶飞机观测特征

利用3次沙尘天气期间的气溶胶飞机观测资料,分析了北京地区在3种沙尘天气下气溶胶垂直分布特征。结果显示:逆温层的存在对扬沙个例的垂直分布有影响。数密度谱的分布基本呈单调递减,但边界层内扬沙、浮尘和沙尘暴个例都在0.13~0.3μm间存在峰值,而扬沙个例在0.8μm,浮尘个例在6.5μm以及沙尘暴个例在2.8和6.5μm处出现次峰值。沙尘中细粒子的有效直径是人为源气溶胶粒子的4到10倍。浮尘天气整个粒子谱宽从近地面层开始随高度先增大后减小,到3000m达到最大,这与高空输送有关;扬沙个例沙尘粒子谱分布显示近地面层大于50μm段粒子谱无论数浓度还是谱宽都明显高于浮尘和沙尘暴个例,这与扬沙是局地大风扬尘引起有关;沙尘暴个例谱宽在接近云底达到最大,说明大粒子已经被携带到一定高度,与蒙古气旋云系的上升运动有关。     

2006年北京一次持续浮尘天气过程的分析

使用NCEP/NCAR再分析资料对2006年4月7~11日北京浮尘天气过程的持续性进行分析,指出此次浮尘天气过程主要受500 hPa西西伯利亚冷涡、鄂霍次克海暖高压以及青藏高原高压脊影响;700 hPa有干冷空气不断向北京地区输送,冷平流和斜压性都很强,大风和沙尘暴发生在强冷平流区域;由于华北南部地区近地面至中低层存在弱的不稳定层结,容易产生弱的上升运动。在近地面低压前部偏东风的作用下将沙尘粒子向北京地区输送,北京地区上空大气在中低层基本处于中性或不稳定层结状态,沙尘粒子不易在北京上空沉降,造成较长时间的浮尘天气。     

甘肃省春季一次连续浮尘天气过程分析

2013年3月8~9日甘肃省出现了一次区域性的大风沙尘暴天气过程,此后到14日甘肃中东部一直维持浮尘天气,这样范围广、持续时间长的沙尘天气为近年来罕见。本文分析了此次沙尘天气过程的天气气候特征以及特殊气象条件对连续浮尘天气的影响,并以兰州市为例基于HYSPLIT-4轨迹模式探讨了浮尘天气过程的沙尘颗粒传输特征。结果表明:(1)前期暖干的气候背景有利于此次大范围沙尘天气的发生;(2)8~9日冷锋后的偏北大风引发甘肃省出现区域性大风沙尘暴天气,11日河西再次出现扬沙、沙尘暴天气,沙尘粒子沿西北气流向下游地区输送,致使12日河东出现浮尘天气的站数明显增多;(3)9日大风沙尘暴天气过后,甘肃省中东部边界层处在弱的偏东风环境中,大气层结长时间较稳定,沙尘污染物不易扩散;(4)在连续浮尘天气期间,甘肃省各地上空频繁出现逆温层,且逆温层高度在9日沙尘暴天气过后有明显抬升,阻挡了低层空气的上升运动,以致沙尘粒子聚集在700 h Pa以下。同时还发现,边界层上部逆温层的逆温温差越大,厚度越厚,造成浮尘天气的强度越强;(5)兰州市9~10日出现的浮尘天气起源于8日河西走廊及蒙古地区的沙尘暴,11日河西走廊再次爆发的沙尘暴天气对河东的浮尘天气影响较大。此外,10~13日陕西南部也出现了浮尘天气,"东高西低"的地面形势使此地上空漂浮的沙尘粒子处在偏东风的环境中,对甘肃中东部地区的浮尘天气有一定的回流输送作用。     

北京春季一次持续浮尘和污染天气过程分析

2001年4月底5月初北京地区出现了一次以浮尘天气为主，夹杂轻雾、雷阵雨、烟幕等复杂天气过程的持续重污染事件，给北京地区的生产和生活带来了较大的影响。文章主要从天气形势上分析了北京浮尘天气形成的原因和持续空气污染的气象条件。结果表明，此次过程是由于高空冷涡发展东移，蒙古气旋发展和地面冷锋移动经过蒙古国南部和华北北部等干燥、疏松的地表形成扬沙、沙尘暴，大量的细小沙尘粒子随高空偏西气流携带而至北京，形成浮尘天气。本地低空处于弱辐合区，层结稳定，风速小、逆温频繁，这些均不利于沙尘粒子和本地污染物的扩散，导致连续可吸入颗粒物重污染的形成。     

贺兰山地区沙尘气溶胶粒子谱分布的观测研究

1996年至1999年4年间的4月和5月，在贺兰山的东西两侧沙漠地区用APS-3310A型激光空气动力学粒子谱仪进行了大气气溶胶数浓度和质量浓度的观测，取得了大量背景大气、浮尘、扬沙和沙尘暴天气条件下的沙尘粒子谱分布资料，通过统计分析研究，总结出不同沙漠地区不同沙尘天气条件下的大气气溶胶粒子谱的分布规律。     

2010年杭州地区一次持续浮尘天气成因分析

利用National Centers for Environmental Prediction及环境监测站大气成分监测资料,分析了2010年3月21—22日杭州地区浮尘天气的影响系统及污染特征,得出"3.21"浮尘天气发生时,空气质量等级为重度污染,吸入颗粒物的浓度达到罕见的高值;浮尘天气源自北方蒙古的沙尘暴,并随着强冷空气先自西向东、后自北向南先后影响到我国西北、华北、东北至华东北部地区、长江中下游等地区。当700 hPa高空槽过境,干冷空气侵入且配合下沉运动时,大量沙砾被带到近地面,"浮尘"天气爆发;之后在高压系统控制下,近地面风向的迅速变化,较湿的偏东气流阻滞及弱的湍流作用,使得沙尘粒子难以扩散,不易沉降,浮尘天气维持。     

德州一次沙尘天气过程成因及气溶胶粒子的输送路径分析

利用NCEP 1°×1°再分析资料分析了2017年5月4日浮尘和5月5日扬沙天气的成因。结果表明：3日20时—4日08时,蒙古气旋在有利的环流背景下迅速发展,配合冷锋在内蒙古中部和东部形成大范围的强沙尘天气;4日20时—5日08时沙尘通过高空气流输送到华北地区,在自身沉降和较强下沉气流的共同作用下,迅速沉降形成华北地区大范围的浮尘天气;5日08—14时由于西北路冷空气影响,横槽转竖,冷锋加速南下,将大量沙源地的沙尘输送到德州造成扬沙天气。通过HYSPLIT模式对本次过程中气团后向轨迹的模拟,证实以上两个阶段沙尘天气过程中的输送方式及路径。通过分析影响系统、物理量和气象要素发现,蒙古国、我国内蒙古中部沙源地天气系统强度、位置的变化直接影响沙尘天气的类型,高层气流变化与沙尘天气的类型有很好的对应关系。     

一次浮尘过程气溶胶光学特性及其辐射效应的研究

利用激光雷达对2006年6月17日出现浮尘天气进行观测,反演分析浮尘天气气溶胶消光系数特征,并将其消光系数放入LOWTRAN模式中模拟了大气长波冷却率。结果表明:浮尘刚出现时沙尘的消光系数较小,其峰值在地面附近,相应光学厚度也较小。浮尘发展时沙尘的消光系数增大,沙尘粒子慢慢从地面上升至高空,边界层高度达1 500 m左右,边界层内部沙尘气溶胶充分混合,消光系数趋于一致,光学厚度最大达0.41;17日浮尘期间(19:00—23:00),2 200 m以下20:00 h和21:00 h冷却率较其它时刻大,这两个时刻的沙尘浓度也较大;有浮尘时长波冷却率较无浮尘时增加,最大增加值在2 250 m的高度层达到0.04 K/h。      

贺兰山地区沙尘气溶胶瞬时谱分析及拟合

利用APS-3310A型激光空气动力学粒子谱仪，1998年4、5月和1999年4月在贺兰山附近的巴音浩特、盐池、银川等地采集了具有代表性的背景大气、浮尘、扬沙、沙尘暴天气条件下沙尘粒子谱分布资料。对粒子瞬时谱的统计分析发现：不同的沙尘天气过程中，气溶胶的瞬时浓度存在很大差别。扬沙、沙尘暴天气过程中，气溶胶浓度变化较大；浮尘天气过程中，气溶胶浓度变化较小。沙尘现象越强，粗粒子（d〉2．5μm）越多，各粒径段浓度变化越明显。不同过程，粗细粒子对粒子表面积浓度贡献程度不一。沙尘气溶胶粒子谱型为单峰结构，对粒子的瞬时谱进行了谱型拟合，其具有对数正态分布函数的特征。     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

<正>The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth’s climate and environment.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

IMPACT OF ATMOSPHERIC LOW-FREQUENCY OSCILLATION ON THE IMMIGRATION OF NILAPARVATA LUGENS(STL) IN HUNAN AND JIANGXI PROVINCES

Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration.     

A COMPARATIVE ANALYSIS OF ATMOSPHERIC AND OCEANIC CONDITIONS BEFORE THE OCCURRENCE OF TWO TYPES OF EL NIO EVENTS

The atmospheric and oceanic conditions before the onset of EP El Ni?o and CP El Ni?o in nearly 30 years are compared and analyzed by using 850 hPa wind, 20℃ isotherm depth, sea surface temperature and the Wheeler and Hendon index. The results are as follows: In the western equatorial Pacific, the occurrence of the anomalously strong westerly winds of the EP El Ni?o is earlier than that of the CP El Ni?o. Its intensity is far stronger than that of the CP El Ni?o. Two months before the El Ni?o, the anomaly westerly winds of the EP El Ni?o have extended to the eastern Pacific region, while the westerly wind anomaly of the CP El Ni?o can only extend to the west of the dateline three months before the El Ni?o and later stay there. Unlike the EP El Ni?o, the CP El Ni?o is always associated with easterly wind anomaly in the eastern equatorial Pacific before its onset. The thermocline depth anomaly of the EP El Ni?o can significantly move eastward and deepen. In addition, we also find that the evolution of thermocline is ahead of the development of the sea surface temperature for the EP El Ni?o. The strong MJO activity of the EP El Ni?o in the western and central Pacific is earlier than that of the CP El Ni?o. Measured by the standard deviation of the zonal wind square, the intensity of MJO activity of the EP El Ni?o is significantly greater than that of the CP El Ni?o before the onset of El Ni?o.     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

Analysis of Atmospheric Boundary Layer Height Characteristics over the Arctic Ocean Using the Aircraft and GPS Soundings

正ERRATUM to: Atmospheric and Oceanic Science Letters, 4(2011), 124-130 On page 126 of the printed edition (Issue 2, Volume 4), Fig. 2 was a wrong figure because the contact author made mistake giving the wrong one. The corrected edition has been updated on our website. The editorial office is sincerely sorry for any     

Index to Vol.31

正AN Junling;see LI Ying et al.;(5),1221—1232AN Junling;see QU Yu et al.;(4),787-800AN Junling;see WANG Feng et al.;(6),1331-1342Ania POLOMSKA-HARLICK;see Jieshun ZHU et al.;(4),743-754Baek-Min KIM;see Seong-Joong KIM et al.;(4),863-878BAI Tao;see LI Gang et al.;(1),66-84BAO Qing;see YANG Jing et al.;(5),1147—1156BEI Naifang;     

Information for Contributors

正Journal of Meteorological Research is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press,sponsored by the Chinese Meteorological Society.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists and aiming at introduction of the current advancements in atmospheric sciences in China.The journal columns include Articles.Note and Correspondence,and research letters.Contributions from all over the world are welcome.