民勤干旱区冬季浓雾形成的边界层条件分析

利用民勤县气象站过程地面小时观测资料、逐日08时和20时每隔50 m探空资料和NECP再分析资料,对2015年11月9—13日出现在干旱区民勤县的一次罕见浓雾天气过程进行了研究分析。结果表明:前期降水后地面相对湿度增大,为大雾形成提供了必要的水汽条件,稳定的高低层环流配置提供了大雾形成的稳定层结和弱风条件。雾层的厚度和强度与近地面逆温层的强度和厚度、边界层高度、水汽垂直运动以及夜间地气温差绝对值密切相关,边界层高度越高,逆温层越厚,雾层越厚;逆温层越强,夜间地气温差绝对值越小,雾层越强。高空环流形势稳定少动,近地层强逆温层、稳定等温层以及饱和湿层长时间维持,导致此次大雾强度和持续时间异常罕见。     

微波辐射计资料在乌鲁木齐机场持续浓雾天气中的试验应用

利用HTG-3型微波辐射计在乌鲁木齐机场进行试验验证期间获得的数据资料,采集了2016年10月—2017年1月出现的多个持续浓雾天气个例进行分析,结果表明:1)微波辐射计可以实时监测边界层温湿条件演变,有效弥补常规探空资料时间分辨率低的问题,可以在监测持续浓雾演变,研究持续浓雾的形成发展机制,提高临近预报能力上发挥有效作用;2)综合水汽含量(IWV)能够反映空中水汽消长情况。持续浓雾多是水汽缓慢耗散的过程。液态水路径(LWP)的增长波动变化与持续浓雾的生消变化有一定的对应;3)持续浓雾时地面到500～1000 m多为相对湿度95%以上高湿高饱和状态;4)贴地逆温的建立或加强是持续浓雾形成的关键。     

天津城区大雾过程近地面层特征研究

地面倒槽、华北地形槽和地面弱高压是天津冬季雾日多见的地面气压系统。为了解雾事件在上述三种天气系统下近地面层气象要素的演变规律,利用天津市250m气象铁塔梯度观测和常规气象观测资料,分别选取2002、2003和2004年相应气压场下的雾个例,比较分析了冬季雾天近地面层结构及低层水汽分布特征。结果表明:(1)三种天气系统条件下,均存在近地层逆位温层结和增湿现象,近地面40m以下高度为弱风。(2)地面倒槽形势下的平流雾过程中,逆温层结稳定且厚达千米,近地层呈多层逆温或弱逆位温层结;80m以上,雾前风力较强,雾中风力较弱;低空各层水汽显著上升时间提前于起雾时间约15h,且日夜增速持续均匀,雾中呈现出逆湿特征,雾顶超过250m。(3)华北地形槽和地面弱高压下的辐射雾过程中,日落后近地面浅薄逆温层结生成并于05时(北京时间,下同)左右达最强,日出后减弱,于11时左右消散;仅夜间近地层水汽显著增加,且塔层250m逆温强度达到3.0℃时才开始出现,距起雾时间约2～9h;雾形成后,逆温层底抬升,雾体中逐渐演变呈不稳定层结;雾中呈现下湿上干特征,雾厚分别为80m和60m左右。(4)华北地形槽和地面弱高压下的风廓线演变规律有显著差异,即前者80m以上6m.s-1左右南风和北风呈规律性日变化转换特征,而后者250m低层大气恒为弱风控制。     

成都双流机场夏季大雾天气特点及形成机理

利用NCEP 1°×1°再分析资料、成都双流机场自动观测资料,统计分析了2003～2015年双流机场夏季大雾出现时气象要素的特征,并对2003～2015年出现的大雾天气过程进行合成分析,以探寻双流机场夏季大雾的特征和形成机理。结果表明:双流机场夏季大雾均为辐射雾,持续时间较短,风向多为偏南风和西南风,风速较小;大雾发生在降水系统后部的负渦度区内,前期降水为大雾形成提供了充足的水汽条件,前一日20时相对湿度在80%以上,大雾出现时相对湿度在92%以上;在高压系统稳定维持的天气背景下,中高层干空气侵入促使双流机场上空维持上干下湿的结构;下沉气流的存在有利于下沉增温和近地面辐射降温共同形成等温或逆温结构,促进稳定层结的建立,有利于大雾的维持。      

江西省区域性平流雾气象要素特征分析及预报思路

利用江西省2000—2012年常规地面观测资料及探空资料,采用合成和统计方法,分析了54次区域性平流雾的天气形势及气象要素,得到了平流雾逆温层、温湿条件、低层风场及影响系统等统计特征。结果表明:(1)江西省区域性平流雾主要发生于2—3月,北部多于南部。(2)其形势特征为:江南地区低层有较明显的暖湿平流。850 hPa上的切变线或辐合区位于长江流域到江淮一带,925和850 hPa西南风速分别达3~8和7~15 m·s~(-1)。地面形势多为弱低压倒槽和锋面前部的低压,其次为高压底部。(3)850 hPa以下低层有相对湿度≥80%的湿层,500 hPa中层多数有相对湿度≤50%的干层。地面气温和露点多在10~16℃,且达到近饱和。(4)平流雾的逆温结构以单层逆温为主,多数比辐射雾逆温层高、厚度大。逆温强度主要在1~3℃。最后给出了江西平流雾(我国南方)的预报着眼点或预报思路。     

乌鲁木齐机场2021年首场强浓雾特征及成因分析

摘要：利用欧洲中心ERA5 0.25°×0.25°再分析、机场HTG-3微波辐射计、FY4A新一代静止气象卫星、机场跑道自动观测系统(AWOS)等多源观测资料,对2021年11月16日乌鲁木齐机场浓雾天气进行观测、诊断分析。结果表明：机场历年首场强浓雾多出现和维持在11月的早晨-午后,以辐射雾为主,持续3～4 h,此场强浓雾呈现持续时间偏长,辐射和平流兼有的特点。降水后高湿、夜间辐射作用及地面西北风增大至4～5 m·s-1时,利于机场辐射雾形成和上游辐射雾的平流;地面辐合带与强浓雾区有较好对应关系,辐合带北侧为偏北风,南侧为偏南风,当近地面逆温层建立,利于辐合带内雾体爆发性增强;近地层小高压维持静稳流场、近地层东南风层、暖平流和逆温层加强并维持、300 m以下相对湿度95%以上及地面偏北风0～2 m·s-1,利于强浓雾维持;机场升温破坏贴地逆温,地面风速加大至2～4 m·s-1,破坏地面静稳状态,地面辐合带东移至城区一带,逆温层减弱抬升至城区上空时,机场强浓雾消散。对于浓雾监测,综合使用FY4A 的10.8μm-3.75μm通道差、0.83μm、2.2μm、3.75μm能很好的显示雾区范围、雾区温度、雾区移动、雾的消散等特征,利于浓雾区的识别和预报预警。     

一次持续性浓雾天气过程的水汽输送及逆温特征分析

利用地面站观测、大气边界层观测及NCEP再分析资料,对2006年2月13～14日华北中南部一次持续性浓雾过程的水汽输送和逆温特征进行了计算和分析,研究了其与浓雾生、消发展之间的联系.结果表明:暖性弱高压脊和地面变性冷高压的高低空系统配置为浓雾的形成提供了有利的逆温层结和近地面弱风条件;在深厚逆温条件下,南支暖湿水汽的输送和辐合使毛毛雨滴下降过程中蒸发,在近地面较冷气层中再次凝结导致了浓雾的生成;加强北上的低空西南急流为浓雾的启动和长时间维持提供了大量的水汽,有利于逆温层顶抬升,湿层增厚,进而促进了浓雾的生成和发展;西北干冷空气自上而下破坏了深厚浓雾所依存的高湿条件,使雾顶下降雾层变薄,加之日出后的短波辐射使近地层空气升温,近地面的稳定层结被破坏,上下层气流交换增强,从而导致了雾最终消散.结果还表明:在近地面逆温、微风等有利成雾天气条件下,当低层持续适量的水汽辐合时,浓雾同时伴随有毛毛雨现象,当低层水汽辐散时,毛毛雨现象消失.     

2019年1月陕西关中平原一次持续性浓雾天气特征及其爆发性增强成因分析

选用气象自动观测站5 min加密观测资料、探空秒级资料、风廓线雷达资料及欧洲中心ERA5逐小时再分析资料,对2019年1月10—12日陕西关中平原一次持续性浓雾天气的环流形势、生消演变特征及其爆发性增强成因进行分析。结果表明：此次浓雾过程具有强度大、持续时间长、多地爆发性增强的特征。雨后的高湿环境,为此次浓雾过程提供了有利的水汽条件;稳定维持的强逆温层,使大量水汽积聚在近地表不易扩散,为此次浓雾的爆发增强和持续提供了有利的层结条件;关中平原特殊地形作用形成的风场辐合,使水汽充分凝结,有利于强浓雾的发展。触发因子是此次浓雾多地短时爆发性增强的可能原因,如风向的突然转变和近地面冷空气回流等。浓雾爆发增长前静稳指数的提前跃增,静稳天气背景条件下925 hPa高度以下近地面东风回流,可作为该地区大雾爆发增强的参考指标。     

乌鲁木齐机场持续浓雾低空气象要素特征分析

利用乌鲁木齐市L波段雷达系统探空资料，对2014—2016年冬季12月至次年2月乌鲁木齐机场雾日、非雾日，雾日中持续浓雾日和非持续浓雾日的低空温、湿、风等气象要素特征进行了对比分析，结果表明：（1）雾日较之非雾日，近地层湿润层更厚，贴地逆温更厚更强（顶高950 m,强度0.55 ℃/100 m)。风速普遍略小于非雾日，地面为西南风，低空东南风厚度大，起始高度低于500 m，最大风速层低于1200 m。（2）持续浓雾日较非持续浓雾日，贴地逆温或悬垂逆温的第一逆温层底高和顶高更低，平均逆温强度更强，地面西南和近地层偏南风频数大，低空型东南风较强。第一逆温顶高低于600 m，悬垂逆温底高低于100 m，逆温强度大于0.55 ℃/100 m，低空型东南风起始高度高低于300 m，600 m高度以上东南风风速大于等于8 m/s等条件有利于持续浓雾的发生。     

河北省高速公路秋冬季浓雾特征及预报

利用河北省高速公路沿线交通气象站的观测资料,统计2013年和2014年秋冬季浓雾(能见度500 m)过程个例,分析高速公路沿线浓雾的时间分布特征和各气象要素变化。结果表明:(1)18:00—20:00(北京时,下同),浓雾开始出现的频率最高;(2)08:00—10:00,浓雾结束的频率最高;(3)浓雾过程持续时间在12~24 h的频率最高;(4)相对湿度在95%~100%之间,温度露点差在-1.0~2.0℃,风速在0~5.8 m·s~(-1),即相对湿度越大、温度露点差越低、风速越小,则出现低能见度的可能性越大。分析各气象要素与能见度的相关性,最后选定相对湿度、温度露点差、风速、风向、气压、气温、能见度7个气象因子作为网络输入建立BP神经网络模型,并以武强、衡水单站2次浓雾过程中能见度变化为例进行检验,取得较好的试验效果。     

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.