2011年6月大气环流和天气分析

2011年6月环流特征如下：北半球高纬度地区为单一极涡,强度较常年同期偏弱,西太平洋副热带高压较常年偏强,欧亚中高纬环流较平直,多短波槽活动,季风槽较常年略偏弱,槽前西南气流明显。6月,全国平均降水量为102.8mm,比常年同期（97.1mm）偏多5.9%。全国平均气温为20.5℃,比常年同期（19.5℃）偏高1.0℃。月内,我国主要天气气候事件有：长江中下游、华南、西北地区东南部、川渝地区、华北、黄淮、东北南部等地发生暴雨洪涝;有3个热带气旋生成并登陆我国;黄淮等地出现极端高温天气;西北东部、华北、黄淮、江淮北部等地上中旬气象干旱持续发展,下旬干旱缓解;全国23个省（市、区）遭受风雹灾害。     

2011年7月大气环流和天气分析

2011年7月环流特征如下：北半球高纬度地区极涡呈多极型分布,西太平洋副热带高压较常年偏弱,欧亚中高纬盛行纬向环流,多短波槽活动。7月,全国平均降水量为105.8 mm,较常年同期（115.9mm）偏少8.7%。全国平均气温为22.1℃,较常年同期（21.4℃）偏高0.7℃。月内,我国主要天气气候事件有：全国共出现7次强降水过程,但没有发生大范围持续性的严重洪涝灾害;4个热带气旋生成但只有一个登陆我国;新疆、内蒙占西部、江南、华南、江汉、江淮、黄淮、华北等地相继出现高温天气。     

2015年7月大气环流和天气分析

2015年7月环流特征如下：北半球极涡呈多极型,中高纬西风呈5波型分布。西太平洋副热带高压强度偏强。7月全国平均降水量88.7 mm,较常年同期偏少26.5%,为1951年来历史同期最少;全国平均气温为22.1℃,较常年同期偏高0.2℃。月内共出现7次主要降水过程,多站出现极端日降水量。7月共有5个热带气旋在西北太平洋和南海活动,生成个数与常年同期基本持平,并有2个台风(莲花和灿鸿)在我国登陆。新疆出现持续高温天气;华北、黄淮等地出现气象干旱;全国24个省（区、市）遭受风雹灾害。     

2019年7月大气环流和天气分析

2019年7月北半球的大气环流主要特征表现为,极涡呈偶极型分布,较常年同期偏强;欧洲高空冷涡异常偏强,中上旬西太平洋副热带高压位置偏南,下旬北抬。7月全国平均降水量为126.3 mm,较历史常年同期偏多4.7%,江南大部以及西南地区较历史同期显著偏多1倍以上,黄淮、江淮地区降水较常年同期偏少5成以上;全国平均气温为22.1℃,较历史同期略偏高。平均高温日数多于常年同期（4.3 d）,达到了5.7 d,华北南部、黄淮、江淮以及南疆等地高温日数显著偏多,山西、辽宁、新疆、广东等地共61站发生极端高温事件。本月内有7次区域性暴雨天气过程,主要出现在我国南方地区,多站出现极端日降水量。共有4个台风生成,接近历史同期水平,只有1个台风登陆我国,较历史同期偏少。     

2011年1月大气环流和天气分析

2011年1月大气环流主要特征如下:北半球极涡中心位于北美北部,强度比常年同期偏弱.中高纬度地区环流呈现三波型分布,东亚大槽、北美槽强度偏弱,西欧槽接近常年同期,东亚锋区明显南压.南支槽位于90°E附近,强度与常年相当.西北太平洋副热带高压明显偏弱.1月主要气候特点:全国平均气温为-8.3℃,比常年同期(-5.9℃)偏低2.4℃,全国平均降水量为8.2 mm,比常年同期(12.1 mm)偏少3.9 mm.华北、黄淮等地区干旱持续发展,冷空气活动频繁,南方雨雪冰冻灾害严重.月内有3次中等强度冷空气及6次降水过程.     

2017年7月大气环流和天气分析

2017年7月大气环流特征为,极涡呈偶极型分布,主体强度较常年偏强;中高纬环流呈5波型分布,北半球副热带高压强度偏强,西太平洋副热带高压整体位置偏北,脊线持续北抬。7月我国平均气温为23.2℃,较常年同期（21.9℃）偏高1.3℃。全国平均降水量112.5 mm,较常年同期（120.6 mm）偏少6.7%,东北地区西部、江南地区东北部、江淮地区西南部和新疆北部等地降水偏少显著。强降水天气主要出现在东北地区和南方,7月我国出现9次区域性暴雨天气过程,7月13—14日降水过程多方面突破历史极值。7月西北太平洋地区有8个台风生成,其中7个台风活跃,3个台风登陆我国,数量较历史同期明显偏多;台风生成个数与1994、1967和1971年并列为历史同期最多。内蒙古东部出现气象干旱,江淮江汉伏旱发展。中东部地区和新疆持续高温天气,最长持续天数为20 d,1884站出现35℃以上高温天气;高温极值为49℃,发生在吐鲁番站。     

2018年7月大气环流和天气分析

2018年7月大气环流的主要特征是极涡偏强且呈单极型分布,中高纬环流呈4波型,西太平洋副热带高压强度较常年明显偏强,位置较常年明显偏北。7月全国平均气温22.9℃,较常年同期偏高1.1℃,为1961年以来历史同期第三高;全国平均降水量133.8 mm,比常年同期（120.6 mm）偏多11%,与历史同期相比呈现北多南少的分布特征。月内我国有7次区域性暴雨天气过程,多站出现极端日降水量。7月共有5个热带气旋在西北太平洋和南海活动,并有“玛莉亚”、“山神”、“安比”3个台风登陆,生成和登陆个数均较常年偏多。我国中东部出现持续性高温天气,同时强对流天气频发,影响范围较广。     

2016年7月大气环流和天气分析

2016年7月大气环流特征为,极涡呈偏心型分布,主体强度较常年偏强;中高纬环流呈4波型分布,北半球副热带高压强度偏强,西太平洋副热带高压整体位置偏南,脊线南北振荡。7月我国平均气温为22.6℃,较常年同期（21.9℃）偏高0.7℃。全国平均降水量131.8 mm,较常年同期（120.6 mm）偏多9.3%,华北、江淮和江南等地偏多显著。强降水天气主要出现在华北地区和南方,7月我国出现8次区域性暴雨天气过程,7月18—22日降水过程多方面突破历史极值。7月西北太平洋地区有4个台风生成,3个台风活跃,2个台风登陆我国,数量较历史同期明显偏少。第一号台风是1949年以来生成时间第二晚的首个台风。内蒙古东北部出现气象干旱。中东部地区和新疆持续高温天气,最长持续天数为11 d,最大影响1075个站点;高温极值为46.8℃,发生在吐鲁番站。     

2017年3月大气环流和天气分析

2017年3月大气环流的主要特征是极涡偏强且呈单极型分布,中高纬环流呈4波型,西太平洋副热带高压强度较常年偏弱,南支槽强度较常年偏强。3月全国平均气温4.5℃,较常年同期偏高0.4℃;全国平均降水量36.2 mm,比常年同期（29.5 mm）偏多22.7%。月内我国东部地区有2次中等强度冷空气过程;南方地区有3次区域性暴雨天气过程;北方地区有2次沙尘天气过程;江苏、湖南等省局地遭受风雹袭击。     

2012年3月大气环流和天气分析

2012年3月大气环流主要特征是:北半球极涡呈多极型分布,强度较常年同期略偏强;中高纬度环流呈4波型分布,中低纬地区南支槽略偏强,有利西南暖湿空气向我国的输送;西太平洋副热带高压强度偏弱。3月全国平均气温为3.5℃,比常年同期(3.8℃)略偏低0.3℃。全国平均降水量为31.4 mm,较常年同期(28.9 mm)偏多8.7%。月内我国出现了3次主要的冷空气过程,北方出现今年首次沙尘天气过程,南方持续低温阴雨天气。     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on     

Information for Authors

正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography.     

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.     

Connections between the Eurasian teleconnection and concurrent variation of upper-level jets over East Asia

The variation of the East Asian jet stream(EAJS) associated with the Eurasian(EU) teleconnection pattern is investigated using 60-yr NCEP–NCAR daily reanalysis data over the period 1951–2010. The EAJS consists of three components: the polar front jet(PFJ); the plateau subtropical jet(PSJ); and the ocean subtropical jet(OSJ). Of these three jets over East Asia,the EU pattern exhibits a significant influence on the PFJ and OSJ. There is a simultaneous negative correlation between the EU pattern and the PFJ. A significant positive correlation is found between the EU pattern and the OSJ when the EU pattern leads the OSJ by about 5 days. There is no obvious correlation between the EU pattern and the PSJ. The positive EU phase is accompanied by a weakened and poleward-shifted PFJ, which coincides with an intensified OSJ. A possible mechanism for the variation of the EAJS during different EU phases is explored via analyzing the effects of 10-day high-and low-frequency eddy forcing. The zonal wind tendency due to high-frequency eddy forcing contributes to the simultaneous negative correlation between the EU pattern and the PFJ, as well as the northward/southward shift of the PFJ. High- and low-frequency eddy forcing are both responsible for the positive correlation between the EU pattern and the OSJ, but only high-frequency eddy forcing contributes to the lagged variation of the OSJ relative to the EU pattern. The negative correlation between the EU pattern and winter temperature and precipitation anomalies in China is maintained only when the PFJ and OSJ are out of phase with each other. Thus, the EAJS plays an important role in transmitting the EU signal to winter temperature and precipitation anomalies in China.     

<p>PARTITION OF SEASON BASED ON MULTIELEMENTS AND THE DECADAL CHANGE OF SEASON DURATION IN CHINA</p>

<p>Using the multielements similarity measurement method and 1950–C2017 NCEP/NCAR gridded daily reanalysis datasets, we analyzed season duration in China during 1950–C2016, and we defined the element with maximum absolute sensitivity as the key impact element at each point using the sensitivity analysis method. The decadal change of season duration and its key impact element before and after 1980 were studied. The results indicated obvious meridional and zonal differences in the distribution of season duration for the 67-year average, and that the key impact element has the same distribution characteristics as season duration. In addition, complementary relationships were found between the durations of spring and summer, autumn and winter, and the cold and warm seasons. Of those, the complementary relationship between the durations of spring and summer was strongest and the regions of complementarity were numerous. The complementary regions of autumn and winter durations were found mainly in western China. In the cold and warm seasons, the complementary regions were widespread and the complementary relationship was generally weak. Comparison of the periods before and after 1980 revealed an east–Cwest difference in the interdecadal variation of season duration. Interdecadal variation in spring and summer was found concentrated in northern and western regions, while that in autumn and winter was concentrated in the western region. Areas of significant interdecadal variation of the key elements were found concentrated in northern and western regions, corresponding well with the areas of significant interdecadal variation of season duration.</p>     

THE INFLUENCES OF SSTA OVER KUROSHIO AND ITS EXTENSION ON RAINFALL IN NORTHEAST CHINA UNDER THE BACKGROUND OF TWO DIFFERENT EL NIO CASES

By using the gauged rainfall in 160 stations within mainland China and the NCEP/NCAR reanalysis data, the impacts of anomalous SST in Kuroshio and its extension on precipitation in Northeast China were investigated. The results show that a difference in the meridional circulation such as the East Asia/Pacific teleconnection pattern(EAP)may be responsible for the difference in rainfall between 1998 and 2010. In comparison with 1998, the anomalous meridional circulation pattern in 2010 shifted northeastward, and then the western subtropical high, the mid-latitudinal trough and the northeastern Asia blocking high also shifted northeastward, causing intensified convergence of the cold and warm air masses at the southern region and thus more rainfall in the southwestern region and less in the northwestern region. In 1998, the anomalous cyclone, one component of the meridional pattern, located at the Songhuajiang-Nengjiang River basin, resulted in more rainfall in the majority of the area. The results of observation and the model show that the difference in SSTA in Kuroshio and its extension under the background of different El Ni觡o events is the key point:(1) The anomalous warmth moved westward from the mid-Pacific to the east of the Philippine Sea during the central event, which led the heat resources shifting to the northeast in 2010; subsequently, a shift occurred to the north of the anomalous ascent and decent, followed by a warm SSTA in the region of Kuroshio's extension in 2010 and Kuroshio in 1998.(2) The warm SSTA in the Kuroshio extension causing the Rossby wave activity flux strengthened in 2010, and then the westerly jet shifted northward and extended eastward. A warm SSTA in Kuroshio and cold SSTA in its extension in 1998 caused the westerly jet to shift southward and weaken. As a result,the anomalous anticyclone and cyclone shifted northward in 2010, and the blocking high also shifted northward.     

Land-use and sustainability under intersecting global change and domestic policy scenarios: Trajectories for Australia to 2050

Understanding potential future influence of environmental, economic, and social drivers on land-use and sustainability is critical for guiding strategic decisions that can help nations adapt to change, anticipate opportunities, and cope with surprises. Using the Land-Use Trade-Offs (LUTO) model, we undertook a comprehensive, detailed, integrated, and quantitative scenario analysis of land-use and sustainability for Australia’s agricultural land from 2013–2050, under interacting global change and domestic policies, and considering key uncertainties. We assessed land use competition between multiple land-uses and assessed the sustainability of economic returns and ecosystem services at high spatial (1.1 km grid cells) and temporal (annual) resolution. We found substantial potential for land-use transition from agriculture to carbon plantings, environmental plantings, and biofuels cropping under certain scenarios, with impacts on the sustainability of economic returns and ecosystem services including food/fibre production, emissions abatement, water resource use, biodiversity services, and energy production. However, the type, magnitude, timing, and location of land-use responses and their impacts were highly dependent on scenario parameter assumptions including global outlook and emissions abatement effort, domestic land-use policy settings, land-use change adoption behaviour, productivity growth, and capacity constraints. With strong global abatement incentives complemented by biodiversity-focussed domestic land-use policy, land-use responses can substantially increase and diversify economic returns to land and produce a much wider range of ecosystem services such as emissions abatement, biodiversity, and energy, without major impacts on agricultural production. However, better governance is needed for managing potentially significant water resource impacts. The results have wide-ranging implications for land-use and sustainability policy and governance at global and domestic scales and can inform strategic thinking and decision-making about land-use and sustainability in Australia. A comprehensive and freely available 26 GB data pack (http://doi.org/10.4225/08/5604A2E8A00CC) provides a unique resource for further research. As similarly nuanced transformational change is also possible elsewhere, our template for comprehensive, integrated, quantitative, and high resolution scenario analysis can support other nations in strategic thinking and decision-making to prepare for an uncertain future.     

碳交易政策的经济影响:以广东省为例

通过构建广东省两区域动态模型,对广东省碳交易及其他政策措施进行定量评估,分析实施可调控总量的碳交易政策机制对广东省及参与交易部门的经济影响。研究结果表明,按照减排情景到2015年广东完成19.5%的碳强度下降目标,相比基准情景,GDP将减少0.7%;按照强减排情景到2015年将完成20.5%的碳强度下降目标,相比基准情景GDP将减少0.9%;如果在强减排情景的基础上实施碳交易政策,GDP相对基准情景减少0.8%,到2015年实施碳交易政策可减少GDP损失约90亿元,说明广东建立碳排放权交易机制能够发挥支持经济发展和节能减碳双赢的作用。     

Characterization and source apportionment of volatile organic compounds in urban and suburban Tianjin,China

Tianjin is the third largest megacity and the fastest growth area in China, and consequently faces the problems of surface ozone and haze episodes. This study measures and characterizes volatile organic compounds(VOCs), which are ozone precursors, to identify their possible sources and evaluate their contribution to ozone formation in urban and suburban Tianjin,China during the Ha Chi(Haze in China) summer campaign in 2009. A total of 107 species of ambient VOCs were detected,and the average concentrations of VOCs at urban and suburban sites were 92 and 174 ppbv, respectively. Of those, 51 species of VOCs were extracted to analyze the possible VOC sources using positive matrix factorization. The identified sources of VOCs were significantly related to vehicular activities, which specifically contributed 60% to urban and 42% to suburban VOCs loadings in Tianjin. Industrial emission was the second most prominent source of ambient VOCs in both urban and suburban areas, although the contribution of industry in the suburban area(36%) was much higher than that at the urban area(16%). We conclude that controlling vehicle emissions should be a top priority for VOC reduction, and that fast industrialization and urbanization causes air pollution to be more complex due to the combined emission of VOCs from industry and daily life, especially in suburban areas.