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Characteristics of ozone vertical profile observed in the boundary layer around Beijing in autumn

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Journal of Environmental Sciences 2011年第8期23卷 1316-1324页

作者： Zhiqiang Ma Xiaoling Zhang Jing Xu xiujuan Zhao Wei Meng institute of Urban meteorology China Meteorological Administration Beijing 100089 China.

In the autumn of 2008, the vertical profiles of ozone and meteorological parameters in the low troposphere （0-1000 m） were observed at two sites around Beijing, specifically urban Nanjiao and rural Shangdianzi. At night and early morning, the lower troposphere divided into two stratified layers due to temperature inversion. Ozone in the lower layer showed a large gradient due to the titration of NO. Air flow from the southwest brought ozone-rich air to Beijing, and the ozone profiles were marked by a continuous increase in the residual layer at night. The accumulated ozone in the upper layer played an important role in the next day＇s surface peak ozone concentration, and caused a rapid increase in surface ozone in the morning. Wind direction shear and wind speed shear exhibited different influences on ozone profiles and resulted in different surface ozone concentrations in Beijing.

关键词： ozonesonde ground-level ozone in Beijing wind shear

On Constructions of Optimal Truncated Low-Dimensional Dynamical Systems of Navier-Stokes Equations

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Communications in Nonlinear Science and Numerical Simulation 1996年第3期1卷 27-31页

作者： Chuijie WU Hongliang ZRAO(Air Force institute of meteorology Nanjing, 211101)(LNM, institute of Mechanics, CAS, Beijing, 100080)E-mail: wucj@*** Air Force institute of meteorology Nanjing 211101 China

An optimal metliod in constructing low-dimensional dynahacal systems ofNavier-Stokes equations has been outlined in this communication. Results on closed oropen domain viscous flows show that the new method is better ... 详细信息

关键词： Navier-Stokes equations Dynamical system. Optimization

Diagnosis of a Moist Thermodynamic Advection Parameter in Heavy-Rainfall Events

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Advances in Atmospheric Sciences 2011年第4期28卷 957-972页

作者：吴贤笃冉令坤楚艳丽 Wenzhou meteorology Bureau Nanjing University of Information Science and Technology institute of Atmospheric Physics Chinese Academy of Sciences institute of Urban meteorology China Meteorological Administration

A moist thermodynamic advection parameter, defined as an absolute value of the dot product of hori- zontal gradients of three-dimensional potential temperature advection and general potential temperature, is introduced to diagnose frontal heavy rainfall events in the north of China. It is shown that the parameter is closely related to observed 6-h accumulative surface rainfall and simulated cloud hydrometeors. Since the parameter is capable of describing the typical vertical structural characteristics of dynamic, thermodynamic and water vapor fields above a strong precipitation region near the front surface, it may serve as a physical tracker to detect precipitable weather systems near to a front. A tendency equation of the parameter was derived in Cartesian coordinates and calculated with the simulation output data of a heavy rainfall event. Results revealed that the advection of the parameter by the three-dimensional velocity vector, the covariance of potential temperature advection by local change of the velocity vector and general potential temperature, and the interaction between potential temperature advection and the source or sink of general potential temperature, accounted for local change in the parameter. This indicated that the parameter was determined by a combination of dynamic processes and cloud microphysical processes.

关键词： moist thermodynamic advection parameter potential temperature advection general potential temperature heavy rainfall event

Study on the Dynamic Process of the Onset of South China Sea Summer Monsoon

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Acta meteorologica Sinica 2008年第4期22卷 511-521页

作者：张立凤张永垂张铭 institute of meteorology PLA University of Science and Technology

By using the NCEP/NCAR reanalysis data from 1958 to 1997, we first looked into the atmospheric flow conditions in the one month immediately prior to the onset of the South China Sea summer monsoon （SCSSM） each year. A monthly-averaged zonal basic flow of 40-yr composite was then calculated. The stability of Rossby wave in the basic flow was studied based on the spherical barotropic vorticity equation. Furthermore, the spectral function expansion method was adopted to define and compute the evolvement of a developing wave packet. The results indicate that there exists barotropic instability of spherical Rossby wave in the climatically-averaged flow field before the SCSSM onset. The instability is triggered by the westerly jet stream in the Southern Hemisphere, and the strongest instable perturbation lies to the south of the westerly jet stream. The peak of the developing spherical Rossby wave packet propagates from mid and high latitudes to low latitudes, though not crossing the equator, spurring the cumulus convection in the tropical zones. The eruption of the cumulus convection and its spread to monsoon regions help to speed up the adjustment of the general circulation and the SCSSM onset. It is concluded that elements that contribute to the SCSSM onset are on global scale, albeit the onset itself looks like a local phenomenon.

关键词： SCSSM onset spherical barotropic instability- tropic cumulus convection developing wave packet dynamic process

A NUMERICAL STUDY ON THE MECHANISM OF BLOCKING HIGH FORMATION

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Science China Chemistry 1990年第5期33卷 606-612页

作者：罗哲贤 Nanjing institute of meteorology Nanjing 210044 PRC

Numerical integration is performed of the KDV equation of the forced dissipation with the result that it takes about 10 days to transform a high-index circulation into a blocking pattern, in whose establishment and maintenance the thermal forcing and dissipation, nonlinoear advection, and linear dispersion are equally important and serve as three factors of essentiality.

关键词： index cycle blocking forced and dissipative KDV equation.

Association of retreating monsoon and extreme air pollution in a megacity

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Journal of Environmental Sciences 2021年第8期33卷 97-104页

作者： Gufran Beig Aditi Rathod Suvarna Tikle Sujit Maji S.B.Sobhana Indian institute of Tropical meteorology Ministry of Earth SciencesPune 411008India

The world’s top ranked mega city Delhi is known for deteriorated air ***,the analysis of air pollution data of 5 years(2014–2018)reveals that years 2016 and 2017,which were marked by an unusual delayed withdrawal of monsoon,witnessed an unprecedented extreme levels of toxic PM2.5 particles(≤2.5μm in diameter)touching a peak level of~760μg/m3(24 hr average),immediately after the monsoon retreat,surpassing WHO standards by~30 time and Indian national standards by~12 times,jeopardising lives of its ***,the normal monsoon withdrawal years do not show such extreme levels of *** high resolution WRF-Chem model along with meteorological data are used in this work to understand that how the delayed monsoon withdrawal and associated vagarious anticyclonic circulation resulted in trapping externally generated pollutants ceaselessly under colder conditions,leading to historic air quality crisis in landlocked mega city in these selected *** sensitivity analysis confirmed that when WRF-chem model forced the climatology of normal monsoon year(2015)to simulate the pollution scenario of 2016 and 2017 for the above time period,the crisis *** findings suggest that such unusual monsoon patterns are on the hook to spur extreme pollution events in recent time.

关键词： Monsoon Air pollution Climatology WRF-Chem Extreme events PM2.5

PREDICTION OF SEA FOG OF GUANGDONG COASTLAND USING THE VARIABLE FACTORS OUTPUT BY GRAPES MODEL

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Journal of Tropical meteorology 2011年第2期17卷 166-174页

作者：黄辉军黄健刘春霞袁金南毛伟康廖菲 Guangzhou institute of Tropical and Marine meteorology CMA

By analyzing the NCEP 1°×1° reanalysis (2004–2008), a number of predictors (factors of variables) are established with the output from the GRAPES model and with reference to the sea fog data from observational stations (2004–2008) and field observations (2006–2008). Based on the criteria and conditions for sea fog appearance at the stations of Zhanjiang, Zhuhai and Shantou, a Model Output Statistics (MOS) scheme for distinguishing and forecasting 24-h sea fog is established and put into use for three representative coastal areas of Guangdong. As shown in an assessment of the forecasts for Zhanjiang and Shantou (March of 2008) and Zhuhai (April of 2008), the scheme was quite capable of forecasting sea fog on the coast of the province, with the accuracy ranging from 84% to 90%, the threat score from 0.40 to 0.50 and the Heidke skill from 0.52 to 0.56.

关键词： sea fog forecast coastal Guangdong MOS-based distinguishing scheme variable predictors

SURFACE OBSERVATIONS IN THE TROPICAL CYCLONE ENVIRONMENT OVER THE SOUTH CHINA SEA

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Journal of Tropical meteorology 2012年第2期18卷 263-274页

作者：刘春霞万齐林廖菲赵中阔 Guangzhou institute of Tropical and Marine meteorology CMA

In this paper, the observational data from Marine and Meteorological Observation Platform （MMOP） at Bohe, Maoming and buoys located in Shanwei and Maoming are used to study the characteristics of air-sea temperature and specific humidity difference and the relationship between wind and wave with the tropical cyclones over the South China Sea （SCS）. The heat and momentum fluxes from eddy covariance measurement （EC） are compared with these fluxes calculated by the COARE 3.0 algorithm for Typhoon Koppu. The results show that at the developing and weakening stages of Koppu, both these differences between the sea surface and the near-surface atmosphere from the MMOP are negative, and data from the buoys also indicate that the differences are negative between the sea surface and near-surface atmosphere on the right rear portion of tropical cyclones （TCs） Molave and Chanthu. However, the differences are positive on the left fi＇ont portion of Molave and Chanthu. These positive differences suggest that the heat flux is transferred from the ocean to the atmosphere, thus intensifying and maintaining the two TCs. The negative differences indicate that the ocean removes heat fluxes from the atmosphere, thus weakening the TCs. The wind-wave curves of TCs Molave and Chanthu show that significant wave height increases linearly with 2-min wind speed at 10-m height when the wind speed is less than 25 m/s, but when the wind speed is greater than 25 m/s, the significant wave height increases slightly with the wind speed. By comparing the observed sensible heat, latent heat, and friction velocity from EC with these variables from COARE 3.0 algorithm, a great bias between the observed and calculated sensible heat and latent heat fluxes is revealed, and the observed friction velocity is found to be almost the same as the calculated friction velocity.

关键词： tropical cyclones over the South China Sea temperature and specific humidity difference wind-wave

WindSat satellite comparisons with nearshore buoy wind data near the U.S. west and east coasts

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Acta Oceanologica Sinica 2016年第7期35卷 50-58页

作者： ZHANG Lei SHI Hanqing YU Hong YI Xin institute of meteorology and Oceanography People's Liberation Army University of Science and Technology Nanjing 211101 China Beijing institute of Applied meteorology Beijing 100029 China

Nearshore wind speeds retrieved by WindSat are validated by a comparison with the moored buoy observations near the U.S. west and east coasts. A 30 min and 25 km collection window is used for the WindSat wind data and buoy measurements from ]anuary 2004 to December 2014. Comparisons show that the overall root-mean-square error is better than 1.44 m/s near the U.S. coasts, and the result for the east coast is better than that for the west coast. The retrieval accuracy of the descending portions is slightly better than that of the ascending portions. Most buoy-to-buoy variations are not significantly correlated with the coastal topography, the longitude and the distance from the shore or satellite-buoy separation distance. In addition, comparisons between a polarimetric microwave radiometer and a microwave scatterometer are accomplished with the nearshore buoy observations from 2007 to 2008. The WindSat-derived winds tend to be lower than the buoy observations near the U.S. coasts. In contrast, the QuikSCAT-derived winds tend to be higher than the buoy observations. Overall, the retrieval accuracy of WindSat is slightly better than that of QuikSCAT, and these satellite-derived winds are sufficiently accurate for scientific studies.

关键词： WindSat polarimetric microwave radiometer nearshore wind validation