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1.
利用常规气象观测资料、探空资料、污染物浓度及AQI资料、NCEP再分析资料等,对2018年11月24日至12月3日夜间常州持续11 d的强浓雾和严重霾天气过程进行了分析。结果表明：（1）此次雾-霾过程持续时间长、范围广、强度大、污染重。（2）中纬度地区高层持续纬向环流控制、中低层暖脊稳定存在,地面持续受均压场或弱倒槽顶部、弱冷锋前部影响,是这次持续性雾-霾过程的重要天气条件。（3）边界层内弱辐散、负涡度及弱的下沉气流是此次雾-霾天气得以长时间维持、发展的动力因子。近地层长时间水汽饱和且维持小风速利于雾-霾的长时间维持。（4）近地面高强度的贴地逆温长时间维持和持续较低的混合层高度是此次雾-霾形成、发展和长时间维持的重要热力条件。雾比霾的平均混合层高度明显偏低且霾等级越高混合层高度越低,混合层高度的变化先于能见度变化,对雾-霾临近预警有较好的指导作用。（5）弱冷空气渗透、风速适当增加、混合层高度的先期快速下降、负净辐射曝辐量绝对值的明显增大是雾爆发性增强的主要原因。 相似文献
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利用空气质量监测资料、NCEP分析场资料、常规气象观测资料,对2014年1月22日~2月4日四川盆地一次持续性雾霾天气过程的特点及环流背景进行了分析。结果表明:此次持续14天的雾霾天气过程发生在中高纬纬向型环流背景下,青藏高原到四川盆地的西风气流不利于冷空气南下以及降水的产生,同时我国大部分地方处于地面高压内的均压场中,气压梯度力小,近地面风速小,有利于雾霾的形成和维持。大气混合层高度的变化对雾霾之间的转换有很好的指示作用,霾的混合层高度比大雾和轻雾的高,且霾的相对湿度比低,温度露点差比雾大,逆温强度比雾弱,这些都为雾霾之间的转换预报提供了很好的参考依据。 相似文献
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2013年初江苏连续性雾-霾天气的特征分析 总被引：7，自引：1，他引：6
利用FNL资料、污染物颗粒浓度资料以及常规气象资料对2013年1月12—16日江苏地区的连续性雾 霾天气过程的环流形势、地面气象要素特征、大气边界层结构及大气污染状况等进行了分析。结果表明：高空形势变化平稳、中低层的暖平流配合稳定少动的地面气压场为雾 霾天气的发生提供了有利的环流形势;持续变化较小的气压梯度和较低的风速以及相对湿度的增大和PM2.5、PM10的浓度的变化为雾 霾形成和发展提供了条件;雾 霾期间低层都存在不同程度的逆温现象,混合层高度与AQI呈反相关关系,当混合层高度越低,AQI就越高,污染就越严重,能见度就越差;相对湿度的升高和PM2.5在污染物颗粒中的富集,是导致能见度下降和持续污染的首要原因,而强冷空气带来的大风降温是污染物颗粒被快速清除的重要动力机制;影响南京的污染物来源为：黄海、安徽地区、北方污染物的输送和本地的局地污染。 相似文献
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利用常规地面观测资料及气象探空资料,分析了2016年11月3—5日关中地区霾天气过程,结果表明:高空500hPa锋区偏北,中纬度无明显冷空气活动,850hPa暖空气控制,地面弱气压场是导致关中地区霾出现的主要天气背景;近地层为正涡度平流,而925~850hPa为负涡度平流是大范围霾持续的动力结构;霾出现前有暖干空气向关中地区输送,而逆温层持续存在,是霾天气持续的重要原因;气压场稳定,风速偏小,大气混合层高度持续低于650m,致使大气水平和垂直交换能力弱,引发了此次霾天气。霾出现前后气象要素变化特征明显,可为霾的预报提供重要参考。 相似文献
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上海地区低能见度特征分析 总被引：5，自引：1，他引：4
利用上海机场气象观测资料以及同时段的探空资料、大气污染资料,分析了上海地区低能见度的季节和日变化特征,以及影响低能见度的天气因子和大气污染浓度,结果表明:低能见度在12月出现次数最多,其次是1月、11月,6-9月出现最少;05:00-08:00出现频率最高,维持时间在1-5 h内的累积频率达到84.4%.降水、雾、霾等是造成低能见度的天气因子.低能见度日空气污染比较严重.冬季大气边界层稳定比例较高、多层逆温频繁发生、混合层高度低,是上海地区低能见度发生频率较高的主要原因. 相似文献
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江苏盐城地区一次持续雾-霾天气过程的综合分析 总被引：7，自引：3，他引：4
2013年12月上旬江苏盐城地区出现了一次历史罕见的持续重度雾-霾天气,利用盐城市常规气象观测资料、NCEP再分析资料(1°×1°)及环境监测中心站的污染物浓度资料等,对此次过程的环流背景、气象要素、大气层结特征以及动力条件、污染情况等进行了综合性分析。结果发现:12月上旬中高层冷空气势力弱,以纬向环流为主;低层弱的水平风场为雾-霾的发生发展提供了有利的环流背景;稳定的层结特征,近地面高强度的贴地逆温和持续较低的混合层高度是此次雾-霾天气长时间维持的重要因素;边界层内弱正散度及负涡度是此次雾-霾天气得以维持发展的动力因子;通过后向轨迹分型和火点监测资料分析发现:污染物的长距离输送在此次重污染天气的形成过程中起到了一定作用。最后,文中建立了能见度和PM_(2.5)浓度、相对湿度的非线性回归方程,对能见度的预报效果较好,为实际业务应用中雾-霾的预报提供了有利的依据。 相似文献
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根据2007—2013年宁波市每日8次地面观测气象资料,运用罗氏法和统计分析法计算大气混合层高度,分析其在霾日和非霾日的不同日变化特征。结果表明宁波市霾日与非霾日混合层高度均呈白天高,夜晚低的日变化特征,夏季两者差值的日变化波动最明显,波峰时间比其他季节晚3 h。混合层高度日变化趋势与风速、气温、能见度趋于一致,霾等级越重,混合层高度越低。霾日与非霾日的气温差值除冬季呈正变温外,其他季节呈负变温,冬季14时差值最小,夜间加大,春夏季凌晨差值最小,14时最大,秋季波动不明显;风速差值除冬季夜间为正值外,其余季节为负值,秋冬季差值最小、夏季最大。大气处于不稳定状态时,混合层高度随着稳定度增加而逐渐处于稳定状态时,随着稳定度增加而降低,中性大气是宁波易致霾的大气层结。霾日与非霾日大气稳定度表现不一致,中午霾日中性大气占多数,非霾日则是不稳定大气;夜间霾日稳定—弱稳定大气和中性大气所占比例相当,非霾日稳定—弱稳定大气占多数。另外,PM_(2.5)浓度在霾日和非霾日均为白天低、夜间高的日变化特征,但霾日波动大,波峰时间晚于非霾日2 h,峰值浓度也高于非霾日2.7倍;早晨或下午到上半夜是霾日的PM_(2.5)浓度两个上升时段,上午为下降时段;非霾日的两个浓度缓升(降)时段分别出现凌晨和下午(上午和前半夜)。研究成果有助于预报员了解大气混合层高度及其对霾的可能影响,从而提高霾预报预警能力。 相似文献
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浙江省大气混合层高度变化特征分析 总被引：2，自引：0，他引：2
利用2000—2013年浙江4个站点(杭州、舟山、衢州和大陈)每日8个时次的气象数据,采用罗氏法计算分析了混合层高度总体变化特征。结果表明,浙江大气混合层总体呈现北部低、南部高,海岛最高的空间分布特征,舟山最低954m,其次杭州1073m、衢州1181m,大陈最高1631m,具有混合层高度越低,起伏变化越小的特征。混合层高度具有较明显时间特征,杭州、舟山、衢州表现为双峰双谷型,即春季(3—4月)和夏季(7—8月)较高、初夏(6月)和秋冬季(11月至次年2月)较低,大陈为单峰单谷型,即秋冬季较高(12月至次年1月)、春末夏初(5月)较低的季节(月)特征,以及白天高、夜间低的日变化特征。2002年杭州混合层高度明显上升的主要与风速加大、1月和6月日照雨日减少、以及9月雨日偏少和2月日照时数偏多密切相关。风速和大气稳定度是影响混合层高度主要因子,风速3m/s以上时,大气即呈不稳定状态,有利混合层高度抬升。大风速决定大陈最高混合层高度,舟山气温较衢州明显偏低导致其混合层高度偏低,杭州混合层高度高于舟山得益于较高的气温。混合层高度越低,雨日、雨量越明显,(轻)雾越多、能见度越低,反之亦然,另外,轻雾、霾共存频率最高的杭州,混合层高度降低除利于出现雾外,更需警惕中度霾以上天气。研究结果对于认知浙江大气质量评估、污染物扩散能力分布现状具有参考价值,为区域内污染源合理分布提供科学依据。 相似文献
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雾霾天气个例气象条件对比分析 总被引：3，自引：0，他引：3
应用常规观测资料、NCEP 1°×1°再分析资料和L波段探空资料从环流形势、扩散条件和边界层特征3个方面对2013年两次雾、霾天气个例进行对比分析,结果表明:500hPa西北气流冷平流、地面弱风场、垂直速度呈弱上升-下沉的垂直分层特点和逆温是两次雾、霾天气出现和维持的共同特征。地面西北风、850hPa弱冷平流、近地层浅薄的接地逆温(100~200m)和湿层与霾天气对应,地面偏东风、850hPa暖平流、925hPa以下深厚的悬浮逆温(400m)和湿层与雾天气对应,霾过程较雾过程逆温强度强,上升运动高度高。消散时雾较霾下沉运动中心高度低,强度弱;霾消散时接地逆温特征变化不大,雾消散时悬浮逆温有底部抬升和大气稳定层结向中性层结转变的变化特征;但均有下沉气流接地、垂直风切变较强和高层低露点干空气下传到地面的特点。 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Fei LIU Chen XING Jinbao LI Bin WANG Jing CHAI Chaochao GAO Gang HUANG Jian LIU Deliang CHEN 《大气科学进展》2020,37(7):663-670
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. 相似文献
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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. 相似文献
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Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei Lü Yang SUN Tao SONG Wendell W. WALTERS Xuejun LIU Nicholas A. MARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 《大气科学进展》2020,37(9):933-938
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 相似文献
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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。 相似文献
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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 Nio3.4 index in summer and autumn but negatively correlated in spring and winter. 相似文献
20.
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. 相似文献