一次雾霾过程中气象因子与细颗粒物浓度关系的研究

利用常规气象观测资料及逐小时地面自动气象观测和环境监测部门的PM2．5浓度等资料,对2014年1月15～19日河北省持续雾霾天气期间气象因子与PM2．5浓度的关系进行统计分析。结果表明,PM2．5是造成霾阶段水平能见度下降的主要因素,相对湿度在40％～60％之间时,能见度与PM2．5浓度相关性最好,随着相对湿度的增大,PM2．5浓度对能见度的作用呈减小趋势;雾阶段能见度与相对湿度的相关性明显好于PM2．5浓度值。西北大风对河北PM2．5浓度的平均清除率在94．3％,去除时间平均为3．7 h,可使PM2．5空气质量分指数达到优或良的等级,降雪对PM2．5浓度的清除作用明显小于大风,很难将PM2．5空气质量分指数降到优或良。     

GPCP全球降水资料数据集介绍

南京大气资料服务中心最近收到GPCP全球降水资料,包括1°×1°的逐月、逐日全球降水资料和2．5°×2．5°逐月全球降水资料。逐月的资料数据集延伸时段从1979年1月到2008年4月;逐日资料数据集延伸时段从1996年10月到2008年4月。区域范围覆盖全球（0．5°E-359．5°E,89．5°S～89．5°N）;为地面一层,一个变量。统计内容见表1：     

清远地区汛期西南低涡型暴雨统计特征

利用1990～1999年Mieaps和ECMWF2．5°×2．5°再分析资料,对清远汛期暴雨与西南低涡活动进行了统计研究。结果表明,西南低涡中心位于107．0°～113．0°E、22．5°～26．0°N和117．5°～121．0°E、30．0°～33．0°N时,清远地区当日最容易出现区域性暴雨降水,并给出西南低涡型清远地区汛期区域性暴雨预报思路,为该类型暴雨预报提供依据。     

白城市2005年春季第一场透雨天气过程分析

1引言 2005年5月5日-6日白城市出现了入春以来的第一场透雨。降水面积广、持续时间长、降水分布不均匀。各市县雨量为：洮北区19．5mm、洮南市37．7mm、通榆县19.9mm、镇赉县13．7mm、大安市11．5mm，平均降水量为20．5mm。从雨量分布情况看，北部和东部雨量偏小。     

气温 7月偏高8月正常 降水 两月偏少旱象严重

今年7－8月份主要的气候特点是：气温偏高，降水偏少，局地旱情严重。两月中共有7场较明显的天气过程影响我区。1月平均气温和月总降水量7月份月平均气温，北疆地区平均为22．5℃，与常年相比偏高0．5℃。南疆地区平均为26．8℃，与常年相比偏高0．9℃。北疆北部除阿勒泰偏低0．2℃外，北部其它地区均偏高0．2－l．6℃。北疆西部偏高l．0－2．5℃。北疆沿天山一带除奇台偏低0．5℃外，其它地区均偏高0．2－0．8℃。南疆地区：哈密偏低0．2℃，其他地区均偏高0．4－1．5℃，其中和田偏高幅度较大，为2．It，居历史同期第三位。3－7月平均气…     

中低纬度高原山地气候变暖对海拔高度的依赖性

本文利用美国国家大气研究中心（NCAR）T85水平分辨率（～140km）的气候系统模式（CCSM3）在大气CO2含量每年增加1％情景下的模拟输出结果,分析了以青藏高原为代表的中低纬高原山地的温度变化特征。结果表明,随着大气CO2含量的增加,中低纬高原山地气候会显著变暖。地面温度的增加以最低气温最大,其次是平均气温,而最高气温最小。同时,寒冷季节的增温大于温暖季节。而且,气候变暖对海拔高度具有明显的依赖性,即增温幅度通常随海拔高度的增加而增大。青藏高原及其邻近地区（25°～42°N,70°110°E）1～1．5km,3～3．5km和5～5．5km三个高程范围内年平均（最低）气温的增温率分别为3．0（3．3）,3．5（3．7）和4．6（5．4）℃／100a,而冬半年平均（最低）气温的增温率分别达到3．1（3．7）,3．8（4．2）和4．9（5．9）℃／100a。     

深圳市龙华新区PM2．5质量浓度分布特征及来源分析

通过对龙华新区2个监测站点2012年的PM2．5监测数据进行分析,得出新区PM2．5年均质量浓度值为0．043mg／m^3,全年总超标天数为30d,超标率为8．2％。PM2．5污染具有明显的季节性特征,干季污染严重,雨季则较轻。新区常年盛行偏北风,处于东莞、惠州等污染严重区域的下风向,且风速偏小,是新区PM2．5来源及质量浓度升高的重要原因之一。同时,利用大气环境影响评价系统的AERMOD模型对新区PM2,污染质量浓度分布进行模拟,结果显示新区PM2．5主要来自本地污染源,贡献率为51．2％,外地污染源贡献率为48．8％。其中,PM2．5污染主要受机动车尾气和道路扬尘影响,贡献率为32．0％,其次是施工项目和裸露土地影响,贡献率为18．2％,工业污染源影响非常小。     

长江三角洲夏季持续性高温预报方法的研究

采用1999～2008年逐日最高气温观测资料和NCEP逐日再分析资料,统计分析了长江三角洲地区近10a夏季温度的低频周期,揭示了对该地区夏季温度变化产生影响的区域和特征。研究表明,该地区夏季温度的低频周期为10-30d。通过相关分析在42．50～47．5°N、82．5°～90°E,42．5°～47．5°N、80°～90...     

PM2.5有了规范的中文名称

PM2．5是指悬浮于空气中粒径小于等于2．5μm的颗粒物,由于对大气环境质量和人体健康的影响而备受关注。但是PM2．5是字母词,一直没有统一的中文名称,媒体和学界使用的名称较混乱,大多直接用“PM2．5”,也有用“细颗粒物”“可入肺颗粒物”“空气细颗粒物”等。     

青藏铁路青海段夏季温度预测的精度检验

利用高原夏季温度(代用)、年太阳黑子相对数、西宁年平均气温,以及青藏铁路青海段夏季温度制作1990-2000年预测,得出最优子集预测的定性和定量评分高于周期外推,但低于均生函数。周期外推、均生函数、最优子集定性趋势预测的平均评分分别为60％～67％、80％和67．5％,而定量预测误差≤1．0℃的平均评分分别为40％～57％、77．5％～82．5％和70％～72．5％。     

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.     

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.     

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.     

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.