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Numerical study of the effects of local atmospheric circulations on a pollution event over Beijing–Tianjin–Hebei, China

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Journal of Environmental Sciences 2015年第4期27卷 9-20页

作者： Yucong Miao Shuhua Liu Yijia Zheng Shu Wang Bicheng Chen Hui Zheng Jingchuan Zhao department of atmospheric and Oceanic Sciences School of Physics Peking University department of Meteorology The Pennsylvania State University University Park Key Laboratory of Regional Climate–Environment Research for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences department of atmospheric Sciences Yunnan University

Currently, the Chinese central government is considering plans to build a trilateral economic sphere in the Bohai Bay area, including Beijing, Tianjin and Hebei（BTH）, where haze pollution frequently occurs. To achieve sustainable development, it is necessary to understand the physical mechanism of the haze pollution there. Therefore, the pollutant transport mechanisms of a haze event over the BTH region from 23 to 24 September 2011 were studied using the Weather Research and Forecasting model and the FLEXible-PARTicle dispersion model to understand the effects of the local atmospheric circulations and atmospheric boundary layer structure. Results suggested that the penetration by sea-breeze could strengthen the vertical dispersion by lifting up the planetary boundary layer height（PBLH） and carry the local pollutants to the downstream areas; in the early night, two elevated pollution layers（EPLs） may be generated over the mountain areas： the pollutants in the upper EPL at the altitude of 2–2.5 km were favored to disperse by long-range transport, while the lower EPL at the altitude of 1 km may serve as a reservoir, and the pollutants there could be transported downward and contribute to the surface air *** intensity of the sea–land and mountain–valley breeze circulations played an important role in the vertical transport and distribution of pollutants. It was also found that the diurnal evolution of the PBLH is important for the vertical dispersion of the pollutants,which is strongly affected by the local atmospheric circulations and the distribution of urban areas.

关键词： Air pollution Sea–land breeze circulation Mountain–valley breeze circulation WRF model FLEXPART model

Indirect Radiative Forcing and Climatic Effect of the Anthropogenic Nitrate Aerosol on Regional Climate of China

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Advances in atmospheric Sciences 2009年第3期26卷 543-552页

作者：李树王体健庄炳亮韩永 department of atmospheric Science Nanjing UniversityNanjing 210093

The regional climate model （RegCM3） and a tropospheric atmosphere chemistry model （TACM） were coupled, thus a regional climate chemistry modeling system （RegCCMS） was constructed, which was applied to investigate the spatial distribution of anthropogenic nitrate aerosols, indirect radiative forcing, as well as its climatic effect over China. TACM includes the thermodynamic equilibrium model ISORROPIA and a condensed gas-phase chemistry model. Investigations show that the concentration of nitrate aerosols is relatively high over North and East China with a maximum of 29μg m-3 in January and 8 μg m-3 in July. Due to the influence of air temperature on thermodynamic equilibrium, wet scavenging of precipitation and the monsoon climate, there are obvious seasonal differences in nitrate concentrations. The average indirect radiative forcing at the tropopause due to nitrate aerosols is -1.63 W m 2 in January and -2.65 W m 2 in July, respectively. In some areas, indirect radiative forcing reaches -10 W m-2. Sensitivity tests show that nitrate aerosols make the surface air temperature drop and the precipitation reduce on the national level. The mean changes in surface air temperature and precipitation are 0.13 K and -0.01 mm d-1 in January and -0.09 K and -0.11 mm d-1 in July, respectively, showing significant differences in different regions.

关键词： nitrate aerosol indirect radiative forcing indirect climate effect regional climate atmosphericchemistry

A Hybrid Coupled Ocean-Atmosphere Model and ENSO Prediction Study

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Advances in atmospheric Sciences 1999年第3期16卷 405-418页

作者：吴爱明倪允琪 department of atmospheric Sciences Nanjing University 210093 Nanjing

A hybrid coupled ocean-atmosphere model is designed, which consists of a global AGCM and a simple anomaly ocean model in the tropical Pacific. Retroactive experimental predictions initiated in each season from 1979 to 1994 are performed. Analyses indicate that: (1) The overall predictive capability of this model for SSTA over the central-eastern tropical Pacific can reach one year, and the error is not larger than 0.8 degrees C. (2) The prediction skill depends greatly on the season when forecasts start. However, the phenomenon of SPB (spring prediction barrier) is not found in the model. (3) The ensemble forecast method can effectively improve prediction results. A new initialization scheme is discussed.

关键词： hybrid coupled ocean-atmosphere model ENSO prediction seasonal dependence ensemble forecast

A Condensed Gas-Phase Chemical Model and Its Application

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Advances in atmospheric Sciences 1999年第4期16卷 608-618页

作者：王体健孙照渤李宗恺 department of atmospheric Sciences Nanjing University 210093 Nanjing

Using the 'lumped mechanism' and 'counting species' methods, we developed a condensed gas-phase chemical model based on a simplified one. The modified quasi-steady-state approximation (QSSA) scheme and the error redistribution mass conservation technique are adopted to solve the atmospheric chemistry kinetic equations. Results show that the condensed model can well simulate concentration variations of gas species such as SO2, NOX, O-3, H2O2 and conversion rates of SO2 and NOX transformation to H2SO4 and HNO3. These results are in good agreement with those from the simplified model. The conversion rates of SO2 and NOX under different initial concentrations and meteorological conditions are computed, and the results can be directly applied to regional acid deposition model.

关键词： gas-phase chemistry conversion rate

Deduction of the Sensible Heat Flux from SODAR Data

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Advances in atmospheric Sciences 2008年第2期25卷 253-266页

作者：潘乃先李成才 department of atmospheric Sciences School of Physics Peking University

A new method for deduction of the sensible heat flux is validated with three sets of published SODAR （sound detection and ranging） data. Although the related expressions have previously been confirmed by the author with surface layer data, they have not yet been validated with observations from the boundary layer before this work. In the study, selected SODAR data are used to test the method for the convective boundary layer. The sensible heat flux （SHF） retrieved from SODAR data is found to decrease linearly with height in the mixed layer. The surface sensible heat fluxes derived from the deduced sensible heat flux profiles under convective conditions agree well with those measured by the eddy correlation method. The characteristics of SHF profiles deduced from SODAR data in different places reflect the background meteorology and terrain. The upper part of the SHF profile （SHFP） for a complicated terrain is found to have a different slope from the lower part. It is suggested that the former reflects the advective characteristic of turbulence in upwind topography. A similarity relationship for the estimation of SHFP in a well mixed layer with surface SHF and zero-heat-flux layer height is presented.

关键词： mixed layer sensible heat flux similarity relationship SODAR zero-heat-flux layer

Analysis of the Simulated Climatic Characters of the South Asia High with a Flexible Coupled Ocean-Atmosphere GCM

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Advances in atmospheric Sciences 2007年第1期24卷 136-146页

作者：黄樱钱永甫 department of atmospheric Sciences Nanjing UniversityNanjing 210093

The ability of a climate model to reproduce the climatic characters of the South Asia High （SAH） is assessed by analyzing the 110-yr output of a Flexible Coupled GCM, version 0 （FGCM-0）. Comparing the results of FGCM-0 with the NCEP/NCAR reanalysis data, the major findings show that FGCM-0 has better results in simulation of the geopotential height field at 100 hPa, and reproduces fairly the main atmospheric circulation centers. However, there are still some differences in the simulated results compared with the reanalysis data. The coupled model also successfully reproduces the mean seasonal variation of the SAH, that is, it moves from the Pacific Ocean to the Asian continent, remaining over the Tibetan Plateau from winter to summer, and then withdraws from the Tibetan Plateau to the Pacific Ocean from summer to winter. However, such observed relationships between the SAH positions and the summer precipitation patterns cannot be fairly reproduced in the FGCM-0.

关键词： South Asia High (SAH) FGCM-0 geopotential height seasonal variation SAH characteristic parameters

Interdecadal Change in Extreme Precipitation over South China and Its Mechanism

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Advances in atmospheric Sciences 2009年第1期26卷 109-118页

作者：宁亮钱永甫 department of atmospheric Sciences Nanjing University Nanjing 210093

Based on the daily precipitation data taken from 17 stations over South China during the period of 1961-2003,a sudden change in summer extreme precipitation events over South China in the early 1990s along with the possible mechanism connected with the anomalies of the latent heat flux over the South China Sea and the sensible heat flux over the Indochina peninsula are *** results show that both the annual and summer extreme precipitation events have obvious interdecadal variations and have increased significantly since the early ***,the latent heat flux over the South China Sea and the sensible heat flux over the Indochina peninsula also have obvious interdecadal variations consistent with that of the extreme precipitation,and influence different months’ extreme precipitation,*** effects are achieved by the interdecadal increases of the strengthening convection over South China through the South China Sea Summer Monsoon.

关键词： extreme precipitation interdecadal change South China sensible heat flux latent heat flux

Numerical Simulations of Intense Meiyu Rainfall in 1991 over the Changjiang and Huaihe River Valleys by a Regional Climate Model with p-σ Incorporated Coordinate System

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Advances in atmospheric Sciences 1999年第3期16卷 395-404页

作者：刘华强钱永甫 department of atmospheric Sciences Nanjing University 210093 Nanjing

Based on the primitive equation model with p- σ incorporated coordinate system originally developed by Qian et al., a one-way nested fine mesh limited area model is developed. This model is nested with ECMWF T42 data to simulate the extra-intensive rainfall event occurring in the Changjiang and Huaihe River valleys in summer of 1991. The results show that the model has certain capacity to fairly reproduce the regional distribution and the movement of the main rainfall belts. Therefore it can be used as a regional climate model to simulate and predict the short-range regional climate changes.

关键词： Regional model Intensive Meiyu rainfall Numerical simulation

Seasonal Variation of the East Asian Subtropical Westerly Jet and Its Association with the Heating Field over East Asia

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Advances in atmospheric Sciences 2005年第6期22卷 831-840页

作者：况雪源张耀存 department of atmospheric Sciences Nanjing University Nanjing 210093

The structure and seasonal variation of the East Asian Subtropical Westerly Jet （EAWJ） and associations with heating fields over East Asia are examined by using NCEP/NCAR reanalysis data. Obvious differences exist in the westerly jet intensity and location in different regions and seasons due to the ocean-land distribution and seasonal thermal contrast, as well as the dynamic and thermodynamic impacts of the Tibetan Plateau. In winter, the EAWJ center is situated over the western Pacific Ocean and the intensity is reduced gradually from east to west over the East Asian region. In summer, the EAWJ center is located over the north of the Tibetan Plateau and the jet intensity is reduced evidently compared with that in winter. The EAWJ seasonal evolution is characterized by the obvious longitudinal inconsistency of the northward migration and in-phase southward retreat of the EAWJ axis. A good correspondence between the seasonal variations of EAWJ and the meridional differences of air temperature （MDT） in the mid-upper troposphere demonstrates that the MDT is the basic reason for the seasonal variation of EAWJ. Correlation analyses indicate that the Kuroshio Current region to the south of Japan and the Tibetan Plateau are the key areas for the variations of the EAWJ intensities in winter and in summer, respectively. The strong sensible and latent heating in the Kuroshio Current region is closely related to the intensification of EAWJ in winter. In summer, strong sensible heating in the Tibetan Plateau corresponds to the EAWJ strengthening and southward shift, while the weak sensible heating in the Tibetan Plateau is consistent with the EAWJ weakening and northward migration.

关键词： East Asian subtropical westerly jet seasonal variation meridional difference of temperature,heating fields over East Asia