华北地区秋冬季气溶胶污染与不同类型降水的关系     

肖之盛  缪育聪  朱少斌  于扬  杜晓惠  车慧正 《气象学报》2022,80(6):986-998

气溶胶对降水的影响具有很大的不确定性,正确理解和认识气溶胶对不同类型降水的影响对提高天气预报的准确度和全球气候变化具有重要意义。利用GPM-DPR观测资料和MERRA-2再分析资料分析了气溶胶污染与华北地区2014—2020年秋、冬季对流云降水和层状云降水的关系。结果表明:与清洁状况相比,气溶胶污染状况下对流云降水的降水强度有所增强,雨顶高度更高。在污染状态下对流云降水具有粒径小但数浓度高的降水粒子,潜热加热率更高。气溶胶污染与层状云降水的降水强度、雨顶高度等宏观特征不存在明显相关。层状云降水相比对流云降水更容易受到大气水汽条件和垂直上升运动的影响。因此,在气象条件主导降水的情况下,气溶胶污染对华北地区层状云降水的影响很难通过GPM-DPR和MERRA-2数据观测到。   相似文献   

Impacts of Boundary-Layer Structure and Turbulence on the Variations of PM2.5 During Fog–Haze Episodes     

Ju  Tingting  Wu  Bingui  Zhang  Hongsheng  Wang  Zhaoyu  Liu  Jingle 《Boundary-Layer Meteorology》2022,183(3):469-493

Boundary-Layer Meteorology - The precise cause of PM2.5 (fine particular matter with a diameter smaller than 2.5 μm) explosive growth and the contribution of intermittent turbulence...  相似文献   

Effects of convective available potential energy,temperature and humidity on the variability of thunderstorm frequency over Bangladesh     

Wahiduzzaman  Md  Ali  Md. Arfan  Luo  Jing-Jia  Wang  Yu  Uddin  Md. Jalal  Shahid  Shamsuddin  Islam  A. R. M. Towfiqul  Mondal  Sanjit Kumar  Siddiki  Ubaydur Rahaman  Bilal  Muhammad  Qiu  Zhongfeng  Dambul  Ramzah  Eibek  Kutubuddin  Haque  Md. Emdadul 《Theoretical and Applied Climatology》2022,147(1-2):325-346

Theoretical and Applied Climatology - The present study examines the effects of convective available potential energy (CAPE), temperature and humidity on the spatiotemporal variation of...  相似文献   

Changes in air pollutants during the COVID-19 lockdown in Beijing:Insights from a machine-learning technique and implications for future control policy          下载免费PDF全文

Jiabao Hu  Yuepeng Pan  Yuexin He  Xiyuan Chi  Qianqian Zhang  Tao Song  Weishou Shen 《大气和海洋科学快报》2021,14(4):63-69

基于2015-2020年北京35个环境空气站和20个气象站观测资料,应用机器学习方法(随机森林算法)分离了气象条件和源排放对大气污染物浓度的影响.结果发现,为应对疫情采取的隔离措施使北京2020年春节期间大气污染物浓度降低了35.1％-51.8％;其中,背景站氮氧化物和一氧化碳浓度的降幅最大,超过了以往报道较多的交通站点.同时,2020年春节期间的气象条件不利于污染物扩散,导致多次霾污染事件发生.为进一步改善北京空气质量,未来需要优化减排策略.  相似文献   

Comparative research on visibility and light extinction of PM2.5 components during 2014–17 in the North China plain: 2014-2017年华北平原PM2.5组分消光与能见度对比研究          下载免费PDF全文

《大气和海洋科学快报》2021,14(2):100034

Severe air pollution with visibility deterioration has long been a focus in the North China Plain (NCP). In this study, concentration and light extinction analysis of PM_2.5 chemical components were carried out from 2014 to 2017 to study the pollution characteristics in Baoding, a case city of the NCP. The annual average concentration of total PM_2.5 components showed a declining trend, decreasing by 11 µg m⁻³ (water-soluble inorganic ions), 23 µg m⁻³ (carbonaceous aerosols), and 1796 ng m⁻³ (inorganic elements). Contributing 82.9% to the concentration of total ions, the dominant components, NH₄⁺, NO₃⁻, and SO₄²⁻ became the main pollutants in PM_2.5 pollution. Based on the IMPROVE algorithm, the average reconstructed PM_2.5 mass concentration was 93 ± 69 µg m⁻³ during the observation period. Meanwhile, the light extinction coefficients were 373.8 ± 233.6 M m⁻¹, 405.3 ± 300.1 M m⁻¹, 554.3 ± 378.2 M m⁻¹ and 1005.2 ± 750.3 M m⁻¹, in spring, summer, autumn, and winter, respectively. Ammonium sulfate, ammonium nitrate, and organic matter were the largest contributors to light extinction, accounting for a total of 55%–77% in the four seasons. The b_sca (light scattering by particles and gases) reconstructed from PM_2.5 components (Rb_sca) and the b_sca converted from visibility (Vb_sca) were compared to evaluate the performance of the IMPROVE algorithm, revealing a high correlation coefficient of 0.84. The high values of Vb_sca were underestimated while the low values were overestimated, as determined through comparison with the one-to-ne line. Especially, when Rb_sca > 1123 M m⁻¹ (corresponding to < 2.0 km, approximately), Vb_sca was underestimated by 17.6%. PM_2.5 mass concentration and relative humidity also had an impact on the estimation.摘要华北平原大气污染与低能见度状况一直是人们关切的问题.本文通过分析2014 - 2017年PM_2.5化学成分的浓度和消光效果, 研究了华北平原典型城市保定市的大气污染特征.结果表明, PM_2.5组分的年均浓度显示下降趋势, 水溶性无机离子,碳质气溶胶和金属元素分别减少了11 µg m⁻³, 23 µg m⁻³和1796 ng m⁻³.NH₄⁺,NO₃⁻和SO₄²⁻是PM_2.5污染的主要污染物, 三者之和占总离子浓度的82.9%.基于IMPROVE方程对细颗粒物进行重构, 在观测期间PM_2.5质量浓度平均为93 ± 69 µg m^−3, 春季,夏季,秋季和冬季的消光系数分别为373.8 ± 233.6 M m⁻¹,405.3 ± 300.1 M m⁻¹,554.3 ± 378.2 M m⁻¹和1005.2 ± 750.3 M m⁻¹.硫酸铵,硝酸铵和有机物对消光的贡献最大, 不同季节下占比达55% ~77%.通过PM_2.5组分进行重构, 利用IMPROVE算法计算得到Rbsca, 用能见度测量值转换得到Vbsca, 二者具有较高的相关性 (r²=0.84) ;但存在Vbsca的高值被低估, Vbsca的低值被高估的现象;特别是当Rbsca > 1123 M m⁻¹ (对应能见度约小于2.0 km) 时, Vbsca的值被低估了17.6%.高浓度PM_2.5和高湿度对IMPROVE算法结果有显著的影响.  相似文献   

Simulation of the QBO in IAP-AGCM: Analysis of momentum budget: IAP-AGCM对QBO模拟的动量收支分析          下载免费PDF全文

《大气和海洋科学快报》2021,14(3):100021

The quasi-biennial oscillation (QBO), a dominant mode of the equatorial stratospheric (~100–1 hPa) variability, is known to impact tropospheric circulation in the middle and high latitudes. Yet, its realistic simulation in general circulation models remains a challenge. The authors examine the simulated QBO in the 69-layer version of the Institute of Atmospheric Physics Atmospheric General Circulation Model (IAP-AGCML69) and analyze its momentum budget. The authors find that the QBO is primarily caused by parameterized gravity-wave forcing due to tropospheric convection, but the downward propagation of the momentum source is significantly offset by the upward advection of zonal wind by the equatorial upwelling in the stratosphere. Resolved-scale waves act as a positive contribution to the total zonal wind tendency of the QBO over the equator with comparable magnitude to the gravity-wave forcing in the upper stratosphere. Results provide insights into the mechanism of the QBO and possible causes of differences in models.摘要平流层准两年振荡 (QBO) 是赤道平流层 (~100–1 hPa) 变率的主要模态, 可对中高纬地区的环流产生重要影响, 但目前利用通用大气环流模式 (GCM) 对其进行准确模拟仍然是一个挑战.本文利用IAP大气环流模式 (IAP-AGCM) 的中高层大气模式版本 (IAP-AGCML69) 对QBO进行模拟, 并对其动量收支情况进行分析.研究发现, QBO主要是由对流活动引起的重力波强迫 (参数化) 引起的, 但该动量强迫被平流层赤道上升流所引起的平流过程显著削弱.模式可分辨尺度的波动强迫对赤道上空的QBO的总纬向风倾向有正贡献, 在上平流层, 其量值大小与参数化的重力波强迫相当.以上结果提供了对QBO形成机制以及模式模拟差异可能原因的认识.  相似文献   

A high-top version of IAP-AGCM: Preliminary assessment and sensitivity IAP-AGCM: 中高层大气环流模式的初步评估与敏感性分析          下载免费PDF全文

《大气和海洋科学快报》2021,14(2):100025

Extending the atmospheric model top to high altitude is important for simulation of upper atmospheric phenomena, such as the stratospheric quasi-biennial oscillation. The high-top version of the Institute of Atmospheric Physics Atmospheric General Circulation Model with 91 vertical layers (IAP-AGCML91) extends to the mesopause at about 0.01 hPa (~80 km). The high-top model with a fully resolved stratosphere is found to simulate a warmer stratosphere than the low-top version, except near the South Pole, thus reducing its overall cold bias in the stratosphere, and significantly in the upper stratosphere. This sensitivity is shown to be consistent with two separate mechanisms: larger shortwave heating and larger poleward stratospheric meridional eddy heat flux in the high-top model than in the low-top model. Results indicate a significant influence of vertical resolution and model top on climate simulations in IAP-AGCM.摘要提高大气环流模式的模式顶层高度对中高层大气 (如平流层准两年振荡) 的准确模拟至关重要. 本研究将IAP大气环流模型 (IAP-AGCM) 延伸至中层大气顶 (~0.01 hPa, ~80 km) 并提高垂直方向分辨率 (91层) , 发展了一个中高层大气环流模型 (IAP-AGCML91) . 结果表明, 与低层模式相比, 该中高层大气模式在整体上显著减小了平流层尤其是上平流层的冷偏差.研究发现这种改善与两种机制有关:与低层模式相比, 高层模式模拟的短波加热更大, 极区平流层附近的经向涡动热通量更大.上述结果表明, 垂直分辨率和模式顶层高度对IAP-AGCML91的气候模拟有重要影响.  相似文献   

长江三角洲地区大气气溶胶柱单次散射反照率特性研究     

张小林  许梦婕 《南京气象学院学报》2021,13(2):252-256

利用OMI卫星资料2006—2017年的483.5 nm波长的气溶胶柱单次散射反照率日均数据,分析了整层大气气溶胶单次散射反照率在长三角地区的时空分布特征,特别是其年际、月、季节变化特征.长江三角洲地区的大气气溶胶柱单次散射反照率越靠近海洋越大,而越靠近内陆越小.日均气溶胶柱单次散射反照率在0.881~0.971范围内变化,多年的平均值为0.939±0.024,最大分布概率出现在0.965~0.970区间,其值约为25％.长三角地区大气气溶胶柱单次散射反照率的年平均值集中于0.938~0.940之间,年际变化很小,变化值小于1％;月均柱单次散射反照率在6、8、9月有最大值,其值为0.968,而在2月有最小值,其值为0.915;季节平均单次散射反照率在夏季最大,其值为0.968,而在冬季最小,其值为0.919.  相似文献   

西安市PM_2.5城乡差异及与城市热岛的关联研究          下载免费PDF全文

李煜斌  姜蕴聪  杨元建  张建彬  赵纯  高志球 《大气科学学报》2022,45(6):904-916

依据一种基于建筑用地比例和土地利用信息熵的城乡站点划分方法,将西安市环境与气象站点划分为城区、郊区和两类乡村站,讨论其PM_2.5的城乡分布特征及与城市热岛效应强度(Urban Heat Island Intensity,UHII)间的相关关系。结果表明,不同季节西安市呈现不同的PM_2.5城乡分布特征和日变化特征,两类乡村站点PM_2.5差异明显且下风向乡村站点(乡村D)对应的UHII_D对城区和乡村的影响程度大于上风向乡村站点(乡村U)对应的UHII_U。在城区较多本地排放的影响下,乡村PM_2.5浓度与 UHII_U(或UHII_D)相关系数均大于城区。随着UHII_D的增加,城乡PM_2.5相对浓度差值(RUPII_D)整体呈下降趋势且UHII_D与RUPII_D在春夏秋季显著负相关。UHII_D增大,城区近地面PM_2.5的水平扩散能力减弱,但PM_2.5的垂直扩散能力较乡村更强,从而UHII_D通过影响PM_2.5的传输扩散特征,进一步影响西安市RUPII_D。  相似文献   

积雪升华过程对高寒湿地陆气相互作用的影响     

张海宏  苏永玲  姜海梅  晁红艳  苏文将 《冰川冻土》2018,40(6):1223-1230

利用青海玉树隆宝地区2014年12月积雪升华过程的观测资料,分析了积雪升华过程中高寒湿地陆气相互作用特征及积雪深度对陆气相互作用的影响。结果表明：在降雪和积雪升华过程中,高寒湿地浅层土壤温度在短时期内有所升高,而深层土壤温度和土壤体积含水量对降雪过程的响应不敏感。积雪升华过程中净辐射、感热通量和潜热通量的日平均值增加,向上短波辐射的日平均值减少。积雪逐渐升华导致地表吸收的能量增加,同时地表向大气传递的能量也随之增加。随着积雪的逐步升华,感热占比和潜热占比逐渐升高,而土壤热通量占比和热储存占比逐渐降低。积雪深度增加会导致地表反照率和地表比辐射率增大,感热输送系数减小。  相似文献