东亚地区降水离子成分时空分布及其特征分析

利用东亚酸沉降监测网(EANET)观测资料,对2001年东亚地区降水成分的时空分布特征进行了分析,通过与过去的观测进行对比,揭示东亚各地酸雨分布情况及降水化学特性差异,为东亚酸沉降长距离输送模式比较计划提供前期分析资料.分析结果表明:(1)东亚地区降水化学成分表现出明显的地域特征,滨海地区的日本降水含量中Na+、Cl-分别为219、208μmol·L-1居东亚地区之首,而中国西北地区Ca2+、NO-3、NH4+、SO24-、Mg2+、K+含量最高各为755、168、260、768、59.3、53.6 μmol·L-1;降水酸度主要受阳离子Ca2+、NH4+和阴离子SO24-、NO3-的影响.(2)东亚地区降水化学成分季节变化明显,除部分源自人为或工业排放源影响外(如北部地区冬季取暖),东亚地区气候呈季节变化也是影响的主要因子之一.春季沙尘源区沙尘、扬沙频繁,其上空存在较强的西风带,在天气系统冷锋影响下,沙尘粒子易随大风扬起而由锋前强烈抬升气流输送到对流层中层,在高空西风急流作用下输送到下游地区.(3)东亚地区酸雨区降水与以往主要以硫酸型酸雨为主的降水性质不同,除中国西南工业欠发达地区仍为硫酸型外,其他酸雨区均为硫酸和硝酸混合型.表征酸雨类型的特征参量[SO24-]/[NO3-]的比值在中国西南地区为3～5,东南和华南地区为0.5～3;其他各国均在0.5～3之间.     

辽宁农村代表区域降水离子组成及与气态污染物相关性

对辽宁农村代表区域站点——辽中县马龙村观测站2007年2月至2008年1月酸雨、气态污染物浓度观测资料进行了研究。结果表明：辽中站降水的化学组成阴离子主要为SO4^2-和NO3-阳离子主要为NH4和Ca2＋,SO4^2-／NO3-比值为2．9．Na＋／Cl-比值较大,大于1。各种离子浓度冬春季高,夏秋季较低,表明研究区域降水酸化与污染关系不显著。实测的9种主要阴离子、阳离子总浓度比（∑阴离子／∑阳离子）与降水pH值相关性不高,表明目前酸雨研究观测的主要9种阴阳离子不能完全包括降水中的离子组成。降水酸性与近地面污染气体浓度相关各异,pH与NOx、CO、NO2和O3浓度有较明显的负相关,与SO2浓度负相关不明显;降水pH值与颗粒物等碱性污染物浓度正相关明显。降水中主要致酸离子SO4^2-和NO3-的浓度与相应酸性气体污染物SO2和NOx近地面浓度的相关不明显。     

瓦里关大气降水的化学特征

利用2007—2009年瓦里关本底台降水化学观测资料,分析了瓦里关降水的pH值、电导率及Cl-、NO-3、SO2-4、NH+4、K+、Na+、Ca2+、Mg2+等离子成分的分布特征。结果表明,瓦里关pH值和电导率的年平均值分别为6.60和21.26μs/cm,2007—2009年呈逐年升高趋势。根据pH值,瓦里关降水以中性降水为主,占总降水的65.13%,其次为碱性降水,酸雨最少。离子浓度大小排序依次为Ca2+SO2-4Na+NH+4Cl-Mg2+NO-3K+,且存在明显的季节变化特征,K+、Na+、Ca2+、Mg2+有相似的来源。瓦里关降水中SO2-4/NO3-的范围为0.35~16.48,平均值为3.07;2007—2009年SO2-4/NO-3值呈逐年下降趋势;SO2-4/NO-3全年存在两个峰值,分别在4月和9—10月。     

南京气溶胶水溶性离子粒径分布及其随高度的变化

2009年1月对南京市河西生活区距地面1．5、54和80m3处同步进行了大气颗粒物采样,并用离子色谱对样品进行了分析。结果显示,随着高度的增加,PM10和PM2.1的质量浓度逐渐降低,而总离子浓度随高度增加而增大。气溶胶中最主要的3种水溶性离子分别为N03、SO4 2-、Ca2＋,且3个高度的NO3-与SO4 2-浓度之比均大于1,表明该生活区移动排放源已经成为大气气溶胶离子的主要来源。3个高度处各离子粒径分布规律为：SO4 2-、NO3-、K＋在0．43-1．1um出现峰值;Ca2＋、Mg2＋、NO2-在4．7～5．8um出现峰值;Na＋、Cl-、F-在0．43～1．1um和4．7～5．8um出现双峰。     

合肥市降水化学组成成分分析

为研究合肥市降水的化学组成成分,于2010年4—9月在合肥市国家基本气象站设立了采样点,进行降水的采集,对降水化学组成成分进行了测定,并系统分析了化学组成成分的特点。结果表明:合肥降水中阴离子主要为SO24-,阳离子主要为NH4+和Ca2+,[SO24-]/[NO3-]当量浓度比值范围为1.23～6.33,大部分样本的比值<3,说明酸雨类型以硝硫混合型为主。降水的酸度与单一离子当量浓度的相关性并不明显,应该是受多种离子综合影响的结果,SO24-与NO3-,Ca2+与Mg2+,NH4+与SO24-,NH4+与NO3-均表现出较好的相关性。     

一次罕见的辐射-平流雾研究(Ⅱ)——雾水化学性质分析

利用2006年12月24-27日南京市持续浓雾的雾水样品资料,结合雾滴谱仪观测的雾的微物理结构和系留气球探测的边界层资料,分析了本次浓雾雾水的化学特征.结果表明:酸雾的频率达61.5%,平均pH值为5.63;雾水中主要阳离子是NH+4、Na+、Ca2+,主要阴离子是SO42-、NO-3,其次是Cl-;雾水中总离子和SO2-4浓度水平较高,说明本次过程大气污染比较严重;雾水的Na+/Cl-为3.09,明显高于其它地区,Cl-亏损严重,主要是因为此次雾是辐射-平流雾,受到东南海面上吹来的暖湿平流的影响;雾水中的离子浓度远高于雨水中的浓度,但雨水比雾水更酸;雾水离子总浓度与雾滴粒径呈反相关趋势(r=-0.71);浓雾发展过程中,pH值先升后降,前后出现三次起伏,其趋势与各离子和总离子浓度的变化大体相反.     

呼和浩特市降水化学特征分析

对2006年呼和浩特市降水离子监测资料进行分析,结果表明:降水呈碱性,季节分布明显,夏季降水集中且pH值为全年最低,冬季降水量少,pH值较高;SO42-离子为主要致酸离子,阳离子中Ca2+,Mg2+离子的浓度很高;降水中主要成分之间相关性显著,Ca2+的中和作用较强;降水气团的后向轨迹分析表明蒙古国的沙漠地区是呼和浩特冬春季碱性降水的主要来源,夏季较低的pH值降水则部分源于我国的华中、华北地区的酸性污染物中长距离输送。     

岭南山地气溶胶物理化学特征研究

对岭南山地收集的气溶胶样品的质量谱与水溶性离子成分谱的分析表明:总气溶胶质量与诸离子浓度大体在华南大陆的清洁点均值与大中城市均值之间,其分布主要表现为明显的三峰分布,分别位于巨粒子段,大粒子段与亚微米粒子段,主峰值位于巨粒子段。K 的分布最为特殊,仅仅在细粒子段位于0.065~1.1μm处表现为一个明显的峰。气溶胶中均以SO42-为主要阴离子成分,Ca2 为主要阳离子成分,较之华南乡村清洁对照点,除离子浓度成倍增加外,SO42-浓度占了阴离子含量的绝大部分。另外,NO3-、NH4 的含量比华南城市显著减少是其主要特点。在雨季无论是总浓度还是SO42-、Ca2 、Mg2 的浓度均比旱季时明显减少,与降水的清除过程有关。气溶胶中水溶性NH4 、K 、SO42-较多地存在于细粒态粒子中,它们的质量中值直径在旱季比广州大,在雨季略小于广州的情况;而F-、Ca2 、Cl-、Na 较多地存在于粗粒态粒子中。相对于华南土壤而言,旱季的大瑶山和白云山气溶胶中Mg2 、Ca2 有明显富集,SO42-也有一定程度的富集,雨季仅仅白云山上Mg2 有富集现象。通过离子中和情况的讨论,岭南山地气溶胶应呈酸性,对雨水酸化的缓冲能力较差,会加重该区的酸雨危害。     

Real-Time Observation on Water-Soluble Ions of PM_(2.5)in Beijing under the Influences of Different Air Masses in Summer

To further understand the variations of water-soluble ions in PM2.5 in Beijing,the authors observed their concentrations continuously and in high temporal resolution by the system for rapid collection of fine particles and ion chromatography(RCFP-IC) during 12–18 July 2010.These results combined with those of earlier backward trajectory research are used analyzed to determine the causes of concentration changes in water-soluble ions under the influences of two kinds of air masses in summer.The results indicate that concentrations of NO3-,SO42-,and NH4+ were influenced strongly by the continental air mass than by the marine air mass.Cl- and Na+ were not changed significantly.Because the sources of K+,Mg2+,and Ca2+ are mainly concentrated on land,their concentration levels were slightly higher under the control of continental air mass than that of the marine air mass.Variations of NO2- during the observation differed from those of other ions;its concentration was significantly higher under the influence of marine air mass.Moreover,the authors obtain the diurnal variations of eight water-soluble inorganic ions including NH4+,K+,Mg2+,Ca2+,Cl-,NO2-,NO3-,and SO42-.Diurnal variations of NH4+,NO3-,and Cl- showed single peak,which appeared before noon,while SO42- showed two peaks that appeared during rush hours.Those of Mg2+,Ca2+,and K+ showed single peak that appeared in the afternoon.That of NO2- showed with a peak appearing at sunrise and a valley appearing at sunset.     

中国南极长城站1998年大气降水化学特征的初步研究

文中报告了 1998年 1～ 12月 ,在中国南极长城站 (6 2°13′S ,5 8°5 8′W ,海拔 10 .0m)采集的 115个有效降水样品的 pH值、电导率和化学组分分析结果。长城站地区降水的年平均 pH值为 5 .6 2 ,电导率年平均值为 85 .16 μS/cm。秋季期间降水的 pH值和电导率较高 ,其它季节较低。降水中最主要的离子为Cl-,Na+ ,其他离子按平均浓度值依次排列为SO42 -,Mg2 + ,Ca2 + ,K+ ,NO3 -,NH4+ 。除NO3 -,NH4+ 外 ,各主要离子浓度间呈显著正相关 ,表明其来源具有同一性。降水样品的离子组成比例与周围海区的海水接近 ,显示了海盐是降水中可溶性离子的主要来源 ,而其它源只对Ca2 + 有一定贡献。该地区的降水具有较典型的海洋性降水的化学特征     

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.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

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.     

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     

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。     

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.     

Retrieval of outgoing longwave radiation from COMS narrowband infrared imagery

Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed.