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A Monthly Atmospheric Circulation Classification and Its Relationship with Climate in Harbin 认领 引用
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作者 贾丽伟 李维京 +1 位作者 陈德亮 安晓存 《Acta meteorologica Sinica》 2006年第4期402-412,共11页
In this study, the classification scheme developed by Jenkinson and Collison （1977） based on a typing scheme of Lamb （1950） is applied to obtain circulation types from the mean sea-level pressure on a monthly basi... In this study, the classification scheme developed by Jenkinson and Collison （1977） based on a typing scheme of Lamb （1950） is applied to obtain circulation types from the mean sea-level pressure on a monthly basis. Monthly mean sea-level pressure data from 1951 to 2002 are used to derive six circulation indices and to provide a circulation catalogue with 27 circulation types. Five major types （N, NW, C, CSW, and SW） which occurred most frequently are analyzed to reveal their relationships with the temperature of Harbin on various time scales. Stepwise multiple regression is used to reconstruct temperature anomaly. The monthly mean rainfall of all types occurring and the composite maps of three major types （C, CSW, and SW） relevant to Harbin＇s precipitation are studied. The results show that the dominant types in winter are types N and NW. types C, CSW, and SW occur frequently in summer. Types N and NW favor a negative temperature anomaly and correspond to less rainfall, while types C, CSW, and SW often induce a positive temperature anomaly and correspond to more rainfall. Moreover, a successful statistical model can be established with only one of the six indices and large-scale mean temperature. Using the model, 77.3% of the total variance in the temperature anomaly between 1951 and 2002 can be reconstructed. Type C has a close relationship with total rainfall and type C precipitation plays a major role in determining the total rainfall of Harbin in recent years. This classification scheme is a statistical downscaling model and its relationships with temperature and precipitation can be used to forecast regional climate. 展开更多
关键词 atmospheric circulation classification temperature precipitation statistical downscaling Harbin
Influences of synoptic circulations on regional transport,local accumulation and chemical transformation for PM2.5heavy pollution over Twain-Hu Basin,central China 认领 引用
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作者 Jingyan Yao Yongqing Bai +7 位作者 Tianliang Zhao Yan Zhu Xiaoyun Sun Chenghao Tan Jie Xiong Yuehan Luo Weiyang Hu Tong Yang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2025年第8期41-51,共11页
The Twain-Hu Basin(THB),located in Central China,serves as a key juncture where the northerly“polluted”airflows of the East Asian winter monsoon meet the southerly warm and humid airflows.Using the T-PCA(T-mode Prin... The Twain-Hu Basin(THB),located in Central China,serves as a key juncture where the northerly“polluted”airflows of the East Asian winter monsoon meet the southerly warm and humid airflows.Using the T-PCA(T-mode Principal Component Analysis)objective synoptic pattern classification,Flexible Particle-Weather Research and Forecasting(FLEXPARTWRF)model,and Random Forest model,we investigate the influences of synoptic circulations on regional transport,local accumulation,and chemical transformation of PM2.5during heavy air pollution over the THB in January of 2015-2022.The results show that the transport-type synoptic pattern accounts for 65.16%of heavy PM2.5pollution,indicating that regional transport of PM2.5dominates the THB’s heavy air pollution.The PM2.5/CO ratio is higher in the transport-type pattern and positively correlated with PM2.5concentrations,reflecting a higher efficiency of chemical transformation to secondary PM2.5in transport-type pollution compared with the accumulation-type pollution.Transport-type heavy PM2.5pollution is predominantly influenced by upstream anomalous northerly and easterly airflows at the bottom of the high-pressure system,converging with the southern wind in the receptor area over the THB.Accumulation-type heavy pollution exhibits weak wind anomalies in central and eastern China under the control of a uniform pressure field.Furthermore,thermally-induced vertical circulations with sinking airflows in the middle and lower troposphere suppress the vertical air pollutant dispersions.The relative contributions of atmospheric factors for transport-type PM2.5heavy pollution events are 38.0%for dynamical driver,26.8%for thermal driver,and 35.1%for chemical transformation,while in accumulation-type,the contribution rates are 33.9%,36.3%,and 29.7%,respectively.This study elucidates the influences of synoptic patterns on regional transport,local accumulation,and chemical transformation of PM2.5for heavy air pollution,with implications for understanding changes of air quality in the receptor region of regional transport. 展开更多
关键词 Central China PM2.5pollution Regional transport Circulation classification FLEXPART-WRF Random Forest
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Variation Trend of Heavy Pollution Weather Frequency and Its Correlation with Climatic Factors 认领 引用
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作者 SHANG Zhanjun JIN Xiaoxue 《外文科技期刊数据库（文摘版）自然科学》 2026年第2期011-015,共5页
Based on the data of heavy pollution days in the Beijing-Tianjin-Hebei region from 2013 to 2022, combined with climatic factors and circulation classification, this study reveals the formation mechanism and long-term ... Based on the data of heavy pollution days in the Beijing-Tianjin-Hebei region from 2013 to 2022, combined with climatic factors and circulation classification, this study reveals the formation mechanism and long-term variation characteristics of heavy pollution frequency. The results show that the annual number of heavy pollution days presents a three-stage attenuation trend (68 d in 2013 → 19 d in 2021). The number of heavy pollution days in the heating period (32.5 d) is significantly higher than that in the non-heating period (8.7 d) (p<0.001). Spatially, a continuous high-incidence hotspot is formed along Shijiazhuang-Baoding-Tangshan (Moran’s I = 0.37, p < 0.001). Among climatic factors, the 850 hPa geopotential height with a one-month lag shows the strongest correlation with heavy pollution days (r = 0.58, p < 0.01), and the GAM model confirms that its contribution rate to pollution reaches 34%. High-pressure circulation leads to 62% of heavy pollution days through subsidence inversion and weakened wind speed (surface wind speed 1.8 m/s), forming a complete driving chain. This study further discusses the impacts of emission reduction policies, terrain blocking, regional transport, and climate change on heavy pollution weather and provides a scientific basis for precise early warning and hierarchical control of air pollution. 展开更多
关键词 heavy pollution weather climatic factors Beijing-Tianjin-Hebei circulation classification generalized additive model spatial-temporal pattern pollution prevention
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Genetic climatic regionalization of the Balkan Peninsula using cluster analysis 认领 引用 被引量：2
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作者 Peter NOJAROV 《Journal of Geographical Sciences》 SCIE CSCD 2017年第1期43-61,共19页
Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses ... Sea Level Pressure（SLP） data for the period 1950–2012 at 61 stations located in or around the Balkan Peninsula was used. The main concept is that intra-annual course of SLP represents the best different air masses that are situated over the Balkan Peninsula during the year. The method for differentiation of climatic zones is cluster analysis. A hierarchical clustering technique–average linkage between groups with Pearson correlation for measurement of intervals was employed in the research. The climate of the Balkan Peninsula is transitional between oceanic and continental and also between subtropical and temperate climates. Several major changes in atmospheric circulation over the Balkan Peninsula have happened over the period 1950–2012. There is a serious increase of the influence of the Azores High in the period January–Marchwhich leads to an increase of SLP and enhances oceanic influence. There is an increase of the influence of the north-west extension of the monsoonal low in the period June–September. This leads to more continental climatebut also to more tropical air masses over the Balkan Peninsula. Accordinglythe extent of subtropical climate widens in northern direction. There is an increase of the influence of the Siberian High in the period October–December. This influence covers central and eastern part of the peninsula in October and Novemberand it reaches western parts in December. Thusthe climate becomes more continental. 展开更多
关键词 genetic classification regionalization Balkan Peninsula cluster analysis Sea Level Pressure circulation indices
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Influence of the Boundary Forcing on the Internal Variability of a Regional Climate Model 认领 引用 被引量：1
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作者 Kevin Sieck Daniela Jacob 《American Journal of Climate Change》 2016年第3期373-382,共10页
The internal variability of a ten-member ensemble of the regional climate model REMO over Europe is investigated. It is shown that the annual cycle of internal variability behaves differently compared to earlier studi... The internal variability of a ten-member ensemble of the regional climate model REMO over Europe is investigated. It is shown that the annual cycle of internal variability behaves differently compared to earlier studies that focused on other regions. To gain better insight into the dependence of the internal variability on the boundary forcing variability, a circulation type classification is performed on the forcing data. It can be shown that especially in the winter season internal variability is dependent on the circulation type included in the boundary forcing, whereas in the summer season the level and pattern of internal variability is rather independent from the circulation type of the driving field. It is concluded that for Europe the internal variability of REMO in winter is governed by circulation patterns related to the North-Atlantic Oscillation, whereas in summer local processes play a bigger role. 展开更多
关键词 Regional Climate Model Internal Variability Boundary Forcing Circulation Type Classification
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Objective Analysis of Circulation Extremes During the 21 July 2012Torrential Rain in Beijing 认领 引用 被引量：11
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作者 赵洋洋 张庆红 +2 位作者 杜宇 江漫 张季平 《Acta meteorologica Sinica》 2013年第5期626-635,共10页
It has been reported that the heaviest rain event since 1951 hit Beijing on 21 July 2012 （henceforth referred to as the 721 case）.The frequency and extreme attributes of the large-scale circulation patterns observed... It has been reported that the heaviest rain event since 1951 hit Beijing on 21 July 2012 （henceforth referred to as the 721 case）.The frequency and extreme attributes of the large-scale circulation patterns observed during the 721 case are explored by using obliquely rotated T-mode principle component analysis （PCA） and reanalysis data from NCEP/NCAR.The occurrence frequency of the 721-type circulation during the summers of 1951-2012 is 10.9%,while the frequency of torrential rain under this type of circulation is 4.51%.Relative to other rainstorms with similar large-scale circulations during the study period,the 721 case is characterized by a more westward extension of the subtropical high over the western North Pacific,a stronger low-level jet in the lower troposphere over the south of Beijing,a larger amount of ambient precipitable water,and a stronger vertical wind shear over Beijing.Among the 621 days with the 721-type circulation during the study period,the 721 case ranks the 54th in terms of the 925-hPa low-level jet south of Beijing,the 209th in terms of the local vertical wind shear,and the 8th in terms of the local precipitable water.The 721 case is particularly extreme with respect to the 925-hPa low-level jet south of Beijing and local precipitable water.Cases with similar circulations and equal or greater values of the 925-hPa low-level jet south of Beijing and local precipitable water have occurred thrice during the summers of 1951-2012 （i.e.,once every 21 years）. 展开更多
关键词 torrential rain circulation classification low-level jet vertical wind shear precipitable water
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