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《干旱气象》2016,(2)
利用2013~2014年石家庄逐小时PM2.5监测浓度与地面及探空等气象观测资料,从大气的垂直扩散、水平扩散和地面局地环流等方面,探讨气象条件对PM2.5浓度的定量影响关系。结果表明:(1)石家庄PM2.5浓度具有明显的日、月和季节变化特征,早晨08时前后PM2.5浓度最高,下午16时前后浓度最低;冬季PM2.5浓度最高,夏季最低;(2)2 a共出现485 d逆温,其中10~12月出现频率最多,达82.8%~86.2%,逆温致使低层大气垂直运动受阻,不利于污染物扩散;(3)大气混合层高度与PM2.5浓度呈反相关,PM2.5浓度75μg/m3(空气质量优良),对应大气混合层高度平均为1 448 m,而PM2.5浓度≥150μg/m3(空气重污染)的混合层高度降到878 m;(4)受地形影响,石家庄地面风与边界层附近风对污染物的影响明显不同:925 h Pa西南风、地面偏东风不利于污染物扩散;925 h Pa西北风、地面偏西风有利于污染物浓度降低。925 h Pa风速4 m/s、地面偏西风风速2 m/s、地面偏东风风速3 m/s,有利于污染物扩散;(5)降水对污染物有湿清除作用,清除量不仅与降水量有关,还与前期PM2.5浓度有关,且冬季降雪过程对PM2.5的清除作用是降雨的4倍。 相似文献
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对雾-霾过程的综合探测 总被引：3，自引：3，他引：0
通过大气细粒子激光雷达和台站探测仪器,探测北京一次雾 霾天气过程,结合地面观测和高空探测气象要素的变化,分析了该雾 霾天气过程能够持续的气象条件：(1)温度持续上升,相对湿度维持在50%以上,风速基本在2 m·s-1以下,高温、高湿、小风速等气象条件不利于颗粒物的迅速扩散;(2)逆温层的持续存在,大气对流减弱,阻止了颗粒物向高空扩散,颗粒物大量积累。以上两个主要原因造成了该雾 霾天气过程的持续。降水对颗粒物的冲刷、湿沉降作用以及冷空气的到来造成地面风力增大,促使了雾 霾天气过程的最终消散。从细粒子激光雷达探测结果发现,在每天中午雾 霾垂直高度都会降低,整个过程中细粒子激光雷达和地面仪器探测的结果基本一致,但通过激光雷达和L波段探空资料对比发现,在存在饱和水汽天气状况时,细粒子激光雷达探测雾 霾高度偏低。 相似文献
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在北京城区布点实测了冬季 (2000年1月26日~2月2日) 主要空气污染物 (SO2、NOx) 浓度的垂直分布以及边界层气象要素的分布, 并对该时间段内气象条件和污染物浓度分布之间的关系做了初步分析。结果表明:在不利于扩散的气象条件下, 污染物浓度剧增; 随着气象状况的交替变化, 污染物浓度也呈交替变化的规律; 在同一建筑物的不同高度, 污染物浓度分布存在差别; 在同一建筑物不同朝向处, 污染物浓度也存在差异, 特别是在不利扩散的气象条件下, 空气质量差异可达一个级别。此外, 城南和城北处的污染物浓度也有显著的差异。 相似文献
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空气污染的天气形势分析和预报 总被引：4，自引：1，他引：4
空气污染与气象条件有密切的关系。准确地做好与污染有关的天气形势预报,是空气污染气象条件预报的重要依据之一。本文根据北京地区两期试验资料,对试验期间出现的天气形势与二氧化硫浓度做了分析,并在此基础上试做了利于和不利于二氧化硫扩散的地面天气形势分型,得出各种类型天气形势下的气象参数及其临界值。 相似文献
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基于1961—2017年的地面常规气象观测资料以及ERA-Interim再分析资料等数据,采用大气自净能力指数（ASI）建立了重污染气象条件等级判别方法。通过对京津冀及周边“2+26”城市秋冬季大气重污染气象条件的长年代变化特征及其成因的分析,得出以下结论：从大气重污染气象条件多年平均水平来看,山西晋城从发生频次到极端性均为最高,北京、河北廊坊和河南郑州多发,河北保定、石家庄和衡水极端性较高。自1961年以来,虽然京津冀及周边“2+26”城市秋冬季大气重污染气象条件在历史上均有发生,但发生次数在2010年后显著增加,这是导致大气重污染频发的重要因素之一。相比2013—2016年,2017年秋冬季京津冀及周边“2+26”城市大气对污染物的清除能力相对较好,虽然北京不利于污染物扩散的气象条件仍然多发,但极端性明显降低。20世纪80年代和2010年以来京津冀及周边地区大气重污染气象条件发生频次均较多,这受到了气候变化背景下冷空气强度和大气滞留条件变化的明显影响,同时也在一定程度上受到了城市化的影响。 相似文献
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利用NCEP/NCAR再分析资料、地面气象观测资料,重点分析了2013年1月成都地区一次重污染天气过程的天气背景以及地面气象要素演变。结果表明:(1)此次持续的污染天气出现在高空为弱脊控制且位势高度场异常偏高,地面处于变性高压脊或均压场且近地面层风速较弱的静稳天气背景下。(2)产生此次高污染(高AQI)的地面气象条件为:地面冷高压逐渐变性,近地面温度升高,海平面气压降低,近地面相对湿度升高至80%左右,无降水或弱降水,能见度将降低至于10km以下,地面风速减弱。(3)中低层弱风速,弱的水平风垂直切变,700h Pa层附近和近地面层的逆温层,不利于污染物在垂直方向上的扩散,使得污染进一步加剧。 相似文献
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苏州市一次重霾污染天气过程的数值模拟 总被引：1，自引：1，他引：0
本文对苏州地区2015年12月13—15日发生的一次典型的重霾污染天气过程进行了数值模拟,分析了颗粒物及其组分的时空变化特征及其气象影响因子,以期为该区域空气污染治理和预防提供科学依据。结果表明:(1)利用WRF-Chem模式对此次重霾污染天气过程的污染气体成分进行数值模拟后发现,小时平均的PM_(2.5)、PM_(10)、CO、SO_2、NO_2模拟值与实测值的相关系数较高,达到0.68以上,通过了P0.01的显著性检验,且日变化过程对应也较好。(2)通过分析此次污染过程的天气背景,发现污染形成期高空环流比较平直,中层为均匀的弱高压控制,地面受弱高压脊控制,这种形势容易导致颗粒物的堆积。后期地面等压线密集时,风速大,有利于污染物的输送与扩散。(3)通过分析此次污染过程期间气象要素的变化发现,有逆温、风速小、相对湿度大等不利的气象条件是导致此次污染过程发生的重要原因之一。(4)HYSPLIT轨迹分析显示,此次重霾过程主要受北方大范围灰霾颗粒物南下影响,北方污染气团逐步南推,14至15日本地大气扩散条件差、污染物累积,最终导致本地污染加重,从而发生重霾事件。(5)火点图的分布进一步验证了此次重霾污染过程是由外来污染气团输入所导致。 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
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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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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(Stl), 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. 相似文献
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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. 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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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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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