It is still not well understood if subseasonal variability of the local PM_(2.5) in the Beijing-Tianjin-Hebei(BTH)region is affected by the stratospheric state.Using PM_(2.5) observations and the ERA5 reanalysis,the e...It is still not well understood if subseasonal variability of the local PM_(2.5) in the Beijing-Tianjin-Hebei(BTH)region is affected by the stratospheric state.Using PM_(2.5) observations and the ERA5 reanalysis,the evolution of the air quality in BTH during the January 2021 sudden stratospheric warming(SSW)is explored.The subseasonal variability of the PM_(2.5) concentration after the SSW onset is evidently enhanced.Stratospheric circumpolar easterly anomalies lasted for 53 days during the January-February 2021 SSW with two evident stratospheric pulses arriving at the ground.During the tropospheric wave weakening period and the intermittent period of dormant stratospheric pulses,the East Asian winter monsoon weakened,anomalous temperature inversion developed in the lower troposphere,anomalous surface southerlies prevailed,atmospheric moisture increased,and the boundary layer top height lowered,all of which favor the accumulation of pollutant particulates,leading to two periods of pollution processes in the BTH region.In the phase of strengthened East Asian winter monsoon around the very beginning of the SSW and another two periods when stratospheric pulses had reached the near surface,opposite-signed circulation patterns and meteorological conditions were observed,which helped to dilute and diffuse air pollutants in the BTH region.As a result,the air quality was excellent during the two periods when the stratospheric pulse had reached the near surface.The increased subseasonal variation of the regional pollutant particulates after the SSW onset highlights the important role of the stratosphere in the regional environment and provides implications for the environmental prediction.展开更多
2022年8月重庆月最高气温达41.3℃,高温日数长达28 d,在此高温天气下8月重庆市区臭氧未出现超标情况,7月整体气温低于8月,出现7 d臭氧超标的情况。利用观测资料、天气研究与预报(Weather Research and Forecasting,WRF)模式,对此现象进...2022年8月重庆月最高气温达41.3℃,高温日数长达28 d,在此高温天气下8月重庆市区臭氧未出现超标情况,7月整体气温低于8月,出现7 d臭氧超标的情况。利用观测资料、天气研究与预报(Weather Research and Forecasting,WRF)模式,对此现象进行分析,并综合探讨不同片区臭氧与气象条件的关系,结果表明:(1)8月的气温和边界层高度偏高、风速偏大,而相对湿度偏低,这可能有利于8月臭氧污染状况改善。整体来看,重庆臭氧质量浓度随气温和边界层高度升高均呈现先升高再降低的趋势,当气温高于30℃、边界层高度高于1000 m、相对湿度低于59%、风速小于6.3 m·s^(-1)时,臭氧质量浓度及超标率均显著上升,而当气温、边界层高度、相对湿度、风速分别超过39℃、2800 m、59%、6.3 m·s^(-1)时,臭氧质量浓度及超标率均显著下降。(2)主城区和郊区县(区)的气温分别超过38℃和37℃后,臭氧质量浓度升幅变小或出现下降,个别县(区)气温为38~40℃时,臭氧质量浓度仍保持上升趋势。(3)沙坪坝区和长寿区在污染日臭氧和边界层高度2 h升幅峰值同时出现在11时或13时,合川区和荣昌区在污染日臭氧和边界层高度2 h升幅峰值出现时间不一致。研究成果可为重庆夏季臭氧污染的预测、防控和管控提供参考。展开更多
使用2008~2012年逐日地面观测资料,揭示了安徽不同地区雾、霾、晴空天气气象条件的差异,指出不同地区要根据本地特点建立雾、霾预报指标和预报方法。3类天气差异最大的地面气象要素是能见度和相对湿度。根据3种天气前一日和当日能见度...使用2008~2012年逐日地面观测资料,揭示了安徽不同地区雾、霾、晴空天气气象条件的差异,指出不同地区要根据本地特点建立雾、霾预报指标和预报方法。3类天气差异最大的地面气象要素是能见度和相对湿度。根据3种天气前一日和当日能见度和相对湿度分布特征,全省站点可以分为3类:1)从雾、霾到晴空,能见度递增、相对湿度递减,且差异显著,如合肥站;2)雾、霾天的能见度和相对湿度均很接近,但与晴空天差别较大,如阜阳站;3)能见度在雾、霾天无明显差别,但相对湿度在雾、霾天差异显著,如安庆站。地级市测站雾后即霾的可能性较大(大于50%),县城测站雾后即霾的可能性较低(低于25%)。垂直方向,雾时相对湿度随高度下降很快,850 h Pa中位值已降到20%(安庆)和45%(阜阳)以下,霾时相对湿度随高度下降缓慢,850 h Pa中位值仍在60%左右;另外,霾天边界层中上部风切变较小,雾天和晴空天边界层中上部都存在较大的风切变。展开更多
This work presents an overall introduction to the Station for Observing Regional Processes of the EarthSystem - SORPES in Nanjing, East China, and gives an overview about main scientific findings instudies of air poll...This work presents an overall introduction to the Station for Observing Regional Processes of the EarthSystem - SORPES in Nanjing, East China, and gives an overview about main scientific findings instudies of air pollution-weather/climate interactions obtained since 2011. The main results summarizedin this paper include overall characteristics of trace gases and aerosols, chemical transformationmechanisms for secondary pollutants like O3, HONO andsecondary ingrganic aerosols, and the airpollution- weather/climate interactions and feedbacks in mixed air pollution plumes from sources likefossil fuel combustion, biomass burning and dust storms. The future outlook of the development plan on instrumentation, networking and data-sharing for the SORPES station is also discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42088101 and 42175069)the National Key R&D Program of China(Grant No.2018YFC1505602).
文摘It is still not well understood if subseasonal variability of the local PM_(2.5) in the Beijing-Tianjin-Hebei(BTH)region is affected by the stratospheric state.Using PM_(2.5) observations and the ERA5 reanalysis,the evolution of the air quality in BTH during the January 2021 sudden stratospheric warming(SSW)is explored.The subseasonal variability of the PM_(2.5) concentration after the SSW onset is evidently enhanced.Stratospheric circumpolar easterly anomalies lasted for 53 days during the January-February 2021 SSW with two evident stratospheric pulses arriving at the ground.During the tropospheric wave weakening period and the intermittent period of dormant stratospheric pulses,the East Asian winter monsoon weakened,anomalous temperature inversion developed in the lower troposphere,anomalous surface southerlies prevailed,atmospheric moisture increased,and the boundary layer top height lowered,all of which favor the accumulation of pollutant particulates,leading to two periods of pollution processes in the BTH region.In the phase of strengthened East Asian winter monsoon around the very beginning of the SSW and another two periods when stratospheric pulses had reached the near surface,opposite-signed circulation patterns and meteorological conditions were observed,which helped to dilute and diffuse air pollutants in the BTH region.As a result,the air quality was excellent during the two periods when the stratospheric pulse had reached the near surface.The increased subseasonal variation of the regional pollutant particulates after the SSW onset highlights the important role of the stratosphere in the regional environment and provides implications for the environmental prediction.
文摘使用2008~2012年逐日地面观测资料,揭示了安徽不同地区雾、霾、晴空天气气象条件的差异,指出不同地区要根据本地特点建立雾、霾预报指标和预报方法。3类天气差异最大的地面气象要素是能见度和相对湿度。根据3种天气前一日和当日能见度和相对湿度分布特征,全省站点可以分为3类:1)从雾、霾到晴空,能见度递增、相对湿度递减,且差异显著,如合肥站;2)雾、霾天的能见度和相对湿度均很接近,但与晴空天差别较大,如阜阳站;3)能见度在雾、霾天无明显差别,但相对湿度在雾、霾天差异显著,如安庆站。地级市测站雾后即霾的可能性较大(大于50%),县城测站雾后即霾的可能性较低(低于25%)。垂直方向,雾时相对湿度随高度下降很快,850 h Pa中位值已降到20%(安庆)和45%(阜阳)以下,霾时相对湿度随高度下降缓慢,850 h Pa中位值仍在60%左右;另外,霾天边界层中上部风切变较小,雾天和晴空天边界层中上部都存在较大的风切变。
基金The work was supported by the National Natural Science Foundation of China （Grant Nos. D0512/91544231, D0512/ 41422504, and D0510/41505109）, National Key Research and Development Program in China （No. 2016YFC0200506）, and Jiangsu Provincial Science Fund （No. BK20140021）. We thank L.F. Zheng, Z.N. Xu, L.S. Jin, E. Herrmann, Y.N. Xie, X.M. Qi, A. Virkkula, Z. Peng, Y.C. Shen, J.P. Wang, H. Shi, L. Wang, C.J. Zhu and H. Shi for their contributions on instrumental maintenance and field campaigns.
文摘This work presents an overall introduction to the Station for Observing Regional Processes of the EarthSystem - SORPES in Nanjing, East China, and gives an overview about main scientific findings instudies of air pollution-weather/climate interactions obtained since 2011. The main results summarizedin this paper include overall characteristics of trace gases and aerosols, chemical transformationmechanisms for secondary pollutants like O3, HONO andsecondary ingrganic aerosols, and the airpollution- weather/climate interactions and feedbacks in mixed air pollution plumes from sources likefossil fuel combustion, biomass burning and dust storms. The future outlook of the development plan on instrumentation, networking and data-sharing for the SORPES station is also discussed.
