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Research On The Problems Of Regional Atmospheric Environmental Quality

Posted on:2009-01-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:C H ChenFull Text:PDF
GTID:1101360242994089Subject:Environmental Engineering
Abstract/Summary:PDF Full Text Request
Regional atmospheric environmental quality in China's economic development is a new important issue. Some researchers began to give attention about regional air environmental quality.To research the characteristics and causes of regional air quality, it's significant that for Government's scientific policy decisions to provide technical support and ultimately achieve regional air quality improvement.To study the formation cause and mechanism of regional air pollution, the air pollution index (API) sequences and the synoptic pressure patterns during autumn and winter from 2002 to 2006 were analyzed with diagnostic and statistical methods in this paper. The results showed that the atmospheric environment has the characteristics of multi-time scale and spatial scales, synoptic patterns of different seasons affects the space-time evolution of pressure field in the boundary layer, which lead to the turn of valley and peak for API value and the concentration of pollutants , in a certain topography and atmospheric conditions, the cumulative increase in the concentration of pollutants results the process, regional and cumulative feature of atmospheric environmental quality. The evolutions of pressure systems in the boundary layer are active factors of regional atmospheric environment. Regional atmospheric environmental quality has the regional synchronous evolutionary characteristics, which is significantly correlated with the evolution of pressure systems.API values increase from the valley to peak and decrease to the valley, which is defined as an environmental process. According to the analysis of regional air pollution process, disadvantageous synoptic patterns to the pollution diffuse lead to the increment of pollutant concentration, which is accumulated daily and forms the peak of the environmental process. Based on a large number of studies and statistics, API increasing phase, peak, decreasing phase are corresponding to high pressure, low pressure field and front zone, which are the mainly synoptic patterns in autumn and winter that affect the atmospheric environmental quality of boundary layer and appear as the evolutionary process.The major weather systems affected the quality of regional atmospheric environment in summer and autumn are typhoons and subtropical high. During the period of Typhoon near the sea or landing China in 2002-2006, We analyzed the important pollutant PM10 and the meteorological data relatively. Results show that there were obvious pollutant processes in the cities in China.Based on the daily mean and increase (decrease) figures of atmospheric environmental monitoring data during 2000-2006, we analyze the subtropical high, results show that the temporal and spatial evolvements of these systems have important influence on the environmental qualities in China because high pressures and transports of wind field lead to accumulate pollutant. Moreover, rain can clear the atmosphere pollutant. The periodic evolvements of synoptic systems form the regional characteristic and periodic evolvements of atmospheric environment. This paper chose and analyze typical example. In the region of the isohypse 5880 geopotential meter at 500 hPa and high pressure at the sea surface , there were large-scale stable and regional pollution process.PM10 values are low in the marginal area of subtropical high.To study synoptic patterns and pollutant transports in regional air environmental processes in North China, typical pollution processes were discussed .Results show that the south-west pathway is dominant in the API increasing phase, pollutant disperse from north to south during the API decreasing phase,the air qualities of most of cities turn good in the influence of front. Results show that south-west pathway is the main transport to cause the regional pollution process with the influence of topography and synoptic patterns.These facts and rules were explained with theory and modeled with WRF in this paper. The Results show that large-scale high and low pressure ,its vertical structure,and long-time stable influence lead to regional air pollution process easily. Typhoon systems are the important reason for the heavy pollution in China for it's very useful to accumulate pollutant in the marginal part and inland in the influence of Typhoon.Modeling results are consistent with diagnose results.WRF can model the meteorological systems of different scales and vertical structure,which can be reparative of observe data for weather stations.
Keywords/Search Tags:Pressure fields, Synoptic patterns, Regional pollution, Tropical pressure, Typhoon, Transport pathway
PDF Full Text Request
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