珠江三角洲大气灰霾导致能见度下降问题研究

大气气溶胶的气候效应和环境效应研究是当今国际科技界的热门话题.近年来珠江三角洲地区的气溶胶污染日趋严重,一年四季长期稳定存在气溶胶云,重污染区偏于珠江口以西的珠江三角洲西侧.灰霾天气主要出现在10月至次年4月.大气灰霾导致能见度恶化.自20世纪80年代初开始,该地区的能见度急剧恶化,灰霾天气显著增加,其中有3次大的波动,分别代表与珠江三角洲经济发展相伴随的气溶胶污染、硫酸盐加气溶胶污染、光化学过程的细粒子加硫酸盐加气溶胶的复合污染时期.雾和轻雾造成的低能见度的长期变化趋势,没有由于人类活动影响或经济发展影响带来的趋势性变化,其波动主要反映了气候波动固有的年际和年代际变化.珠江三角洲能见度的恶化主要与细粒子关系比较大,PM10有一半月均值超过国家二级标准的日均值浓度限值(150 μg/m3),而PM2.5月均值全部超过美国国家标准的日均值浓度限值(65 μg/m3),尤其是10月至次年1月的月均值浓度几乎超过标准限值的1倍,细粒子浓度甚高.另外PM2.5占PM10的比重非常高(58%-77%),尤其是旱季比雨季更高.与15 a前的资料相比较,细粒子在气溶胶中的比重有明显增加,因而在目前珠江三角洲的气溶胶污染中,主要是细粒子的污染.     

南海夏季风撤退期的气候特征I——40年平均

近年来广州地区的气溶胶污染日趋严重,灰霾天气主要出现在10月～次年4月。大气灰霾导致能见度恶化。自1980年代初开始,该地区的能见度急剧恶化,灰霾天气显著增加,其中有3次大的波动,分别代表广州地区经济发展相伴随的粉尘污染、硫酸盐加粉尘污染、光化学过程的细粒子加硫酸盐加粉尘的复合污染时期。雾和轻雾造成的低能见度的长期变化趋势,没有由于人类活动影响或经济发展影响带来的趋势性变化,其波动主要反映了气候波动固有的年际和年代际变化。广州地区能见度的恶化主要与细粒子有关,PM10有一半季均值超过国家二级标准的日均值浓度限值,而PM2.5季均值全部超过美国国家标准的日均值浓度限值,细粒子浓度甚高。另外PM2.5占PM10的比重非常高,可达62%～69%,尤其是旱季比雨季更高。     

广州地区旱季一次典型灰霾过程的特征及成因分析

通过研究2009年11月广州市气溶胶颗粒物质量浓度(PM10、PM2.5、PM1)、黑碳浓度、散射系数(Scatter)等大气成分要素,以及微波辐射计、激光雷达及风廓线雷达所探测的风、温、湿等边界层结构,统计分析广州旱季一次典型灰霾过程(2009年11月23—29日)中气溶胶颗粒物及其光学特性的时空变化特征,并配合天气形势背景、边界层结构对其形成原因进行详细分析。在典型灰霾过程中,黑碳浓度高达58.7μg/m3,散射系数高达1 902.7 Mm-1,PM10浓度高达423.5μg/m3,PM2.5浓度高达355.7μg/m3,PM1浓度高达286.5μg/m3。通过对同期的气象条件分析表明在广州地区旱季,区域性污染过程,特别是灰霾天气的形成具有以下三种气象条件:大气边界层高度较低;高压变性出海的天气形势与之密切相关;在偏东和偏南气流带来的高湿度环境下,气溶胶吸湿增长效应显著,导致出现严重灰霾天气。     

一次热带气旋外围下沉气流造成的珠三角地区连续灰霾天气过程分析

通过研究广州番禺大气成分站的气溶胶颗粒物质量浓度(PM10和PM2.5)、黑碳浓度、臭氧浓度等大气成分要素,常规地面气象要素以及气流后向轨迹、垂直速度、位温和边界层高度等资料,结合热带气旋路径和天气形势对热带气旋外围下沉气流造成的一次珠三角地区连续灰霾天气过程的形成原因和变化特征进行了分析.由于热带气旋移动缓慢,其外围下沉气流使珠三角地区形成了层结稳定、静小风和晴朗少云的天气条件,导致珠三角地区出现连续的灰霾天气.在这次灰霾过程中,气溶胶粒子来源以本地源为主,并且以细粒子为主,PM2.5占PM10的比例接近70％,黑碳浓度占PM10的6.0％左右;在凌晨,由于边界层高度降至最低,垂直扩散条件差,同时相对湿度也达到峰值,气溶胶吸湿增长明显,易出现能见度低值.     

沿海工业城市灰霾天气增多与海盐气溶胶粒子的关系

我国28年前在粉尘污染时代建立的空气质量评价体系,已经远远不能描述新型复合空气污染类型,尤其是不能描述细粒子污染的情况,能见度（vis）的恶化主要与细粒子的质量浓度关系比较大,而与气溶胶的质量浓度关系不大。vis与PM2.5,尤其是PM1有非常好的关系,因而目前用vis来描述灰霾天气是最好的指标。2008年珠三角灰霾的减少与大气环流形势有关,东亚环流径向度较大,冷空气影响岭南地区较为频繁;与2008年下半年爆发的金融海啸引发的加工业开工不足、物流减少亦有关联;另外各级政府对大气环境的治理收到成效也是灰霾天气减少的重要原因。尤其值得注意的是沿海工业城市灰霾天气增长较快,沿海工业城市灰霾天气增多与海盐气溶胶粒子的氯损耗机制关系密切。     

2013年1月华北平原重霾成因模拟分析

2013年1月华北平原出现了罕见的重污染天气过程,并引发连续多天大范围重霾现象。利用中华人民共和国环境保护部公布的空气污染指数日值数据和气象常规观测数据,结合区域空气质量模式系统RAMS-CMAQ的模拟结果,对1月10~15日污染过程的气象要素和关键气溶胶物种时空分布特征进行了详细分析,并对灰霾成因进行了探讨。结果表明,受本次污染过程影响的区域主要分布在北京-天津-唐山、河北省中南部和山东省大部。这些地区细颗粒物(即PM2.5)日均质量浓度超过120μg m–3,且基本被灰霾覆盖,日均能见度在5~8 km之间。其中在北京、天津、石家庄和济南市及周边地区细颗粒物日均质量浓度可达250~300μg m–3,部分市区可超过300μg m–3,而日均能见度则可下降至3 km以下,形成重度灰霾。此外,对气象场的分析显示,本次污染过程期间华北平原大部分地区水平风速较多年平均值偏小约20%,且有明显逆温层覆盖,北京-天津-唐山、河北省南部和山东省北部的相对湿度则较多年平均值偏高达10%~40%。这样的气象条件不仅造成污染物易于堆积,而且有利于吸湿性粒子消光效应的快速增长,使能见度明显下降,是引发灰霾的重要因素之一。在北京地区引发灰霾的主要气溶胶物种为硫酸盐、硝酸盐和铵盐,这3种无机盐对近地面的消光贡献比率达到50%以上。其中硝酸盐的消光贡献比率最高,可达总体效应的1/4,表明在这次污染过程中除相关工业源排放外,交通源排放也是北京地区主要的污染源之一。     

天津一次持续低能见度事件的影响因素分析

2009年1月天津发生了一次持续低能见度事件,从气象条件、污染演化过程和气流后向轨迹等方面分析该次事件是由以细粒子为主的灰霾天气所引起。分析表明,细粒子质量浓度是影响大气能见度的主要因素;细粒子在可吸人颗粒物中的富集,是造成持续性污染和能见度连续下降的主要原因;西南暖湿气流控制下的静稳天气有利于污染物聚集,而以大风降温为标志的冷锋过境是细粒子清除的重要机制;能见度的周期性变化主要依赖于细粒子的富集和污染物的快速清除,并且这一过程受到周期性天气系统的影响。     

珠江三角洲空气质量与能见度数值预报模式系统

珠三角已构建并准业务运行的空气质量与能见度(大气灰霾)数值预报模式系统能反映污染物的产生、聚集和消亡,能模拟大气灰霾的形成过程;预报结果与观测结果随时间演变的趋势比较一致,较好地体现了污染物的日变化特征。通过对2009年11月严重大气灰霾过程的模拟分析表明,广州地区引起灰霾天气的气溶胶主要是细粒子即硫酸盐气溶胶、碳气溶胶(黑碳与有机碳)与铵盐气溶胶的消光作用;在高湿度条件下硫酸盐的消光作用明显增大。     

江西省中北部地区一次典型灰霾天气过程分析

利用气象观测资料、南昌市PM2.5资料并结合HYSPLIT轨迹模型,对2013年12月4—10日江西省中北部地区一次典型、持续性灰霾天气过程进行了分析,综合讨论了灰霾天气发生过程中的天气形势、风速、能见度、低层相对湿度、层结稳定度等气象要素和物理量特征,分析了PM2.5浓度等环境要素的变化特征以及导致此次灰霾天气的污染源。结果表明:1)此次灰霾天气过程的500 h Pa高度层平均环流形势为"两槽一脊"型,江西省受西北偏西气流控制;弱冷空气、静稳天气是灰霾天气得以形成和发展的主要天气背景场。2)较小的近地面风速和较大的相对湿度以及中低层逆温层的存在均是此次灰霾形成和维持的重要条件,且此次灰霾天气过程中能见度分别与近地面风速和相对湿度、PM2.5浓度呈正、反相位关系,湿度升高、污染物浓度较高、风速较低的气象条件容易形成低能见度。3)灰霾天气气溶胶颗粒物浓度的升高可能是由本地污染源和甘肃省、内蒙古自治区一带以及四川省东南部污染源共同造成的;前期整体出现在2 km以下,随着时间的推移,浓度升高。     

2007年春季广州城区黑碳气溶胶污染特征的初步研究

2007年4月利用黑碳仪（Aethalometer）、颗粒物在线观测仪（TEOM1400a）和现时天气现象传感器（PWD22）获得了大气细粒子中每5 min黑碳气溶胶（BC）浓度以及每30 min PM2.5浓度及大气能见度观测数据。结果发现：黑碳日均值浓度为7.4±2.9 μg·m－3,变化范围分别为2.1～11.6 μg·m－3。PM2.5日均值浓度为77.4±35.9 μg·m－3,浓度变化范围分别为29.6～183.3 μg·m－3。黑碳小时浓度变化具有2个明显的峰值,主要与机动车尾气排放密切相关。黑碳浓度与PM2.5浓度呈正相关,与大气能见度呈负相关,相关系数为分别为0.707和－0.529,表明黑碳是PM2.5中的重要组成部分,对大气能见度的影响较显著。     

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.