| Atmospheric boundary layer (ABL) is one of the important layer in the research of atmospher, because human live in this layer and this layer take an role of transporting of matter and energy between underlying surface and the free atmosphere. Otherwise, the height of ABL is one of the most key parameters of atmospheric models, climate models and pollutant dispersion models. Its precision has a crucial effect on the accuracy of model output results. Wind Profiler Radar (WPR) is one of effective observing instruments in boundary layer detection, which can be used to detect the real-time variation of the height of atmospheric boundary layer characteristics. In this paper, WPR data from Dianbai National Climate Observatory, and Bohe Oceanic&Meteorological Science experiment site during summer monsoon in the South China Sea, have been discussed to detect the structure of boundary layer combining with GPS radiosonde data, surface energy balance observations, and automatic weather station data. The variation characteristics of the height of atmospheric boundary layer and meteorological factors that affect the boundary layer height have been analyzed to provide a reference for boundary layer parameterization scheme design and pollution prevention in that areas. Besides, using the WPR data from Shenzhen Shiyan weather station, Jan,2010, wind circulation characteristics in winter was studied, in order to control air pollution in Shenzhen and improving the weather forecast accuracy. The main conclusions are as follows:(1) From the height of ABL which were determined by WPR data and GPS radiosonde data were compared, the results show that the refractive index structure constant and turbulent kinetic energy dissipation rate can determine the boundary layer height very well, and the combination of the two can be better obtianed the turbulent structure of atmospheric boundary layer and the evolution of boundary layer height.(2) The study of WPR data applied in South Sea Mosoon showed that, during the break-in period of monsoon (June29,2012), the boundary layer showed a obvious diurnal variation. At the inland observation site, the turbulence was weak, horizontal wind speed was more strong then daytime, vertical updraft magnitude was smaller at night. In the daytime, turbulence was more stronger, horizontal wind speed had been reduced, by the increasing of vertical speed. The boundary layer height increased first and then decreased, reached a maximum height at around15:00(about1600m). At the coastal observation site, its boundary was affected by offshore wind and onshore wind. Boundary layer height was lower than the result of inland.(3) During the active monsoon period (July2,2012), due to the impact of the prevailing wind, the observed wind of both sites are exhibited a uniform horizontal wind of SE within the boundary layer. Diurnal variation of wind speed was small. Prevailing downdraft affected by the subtropical high prevalence. During in the daytim turbulent activities were significantly weakened in the break-in period of monsoon. Boundary layer height during the period was significantly lower than the break-in period. And diurnal variation is not obvious. Boundary layer height at around11:00reached the heightest level and keeped the height until15:00. The ABL height of inland was about750m, the coastal areas of700m.(4) During the break-in period of monsoon, the height of boundary layer was proportional to the net radiation and the surface temperature, and it was inversely proportional to the relative humidity.(5) The study of WPR data applied in Sea-land breeze showed that, the winter sea-land breeze in Shenzhen had obviously diurnal variation characteristics. The period of sea breeze was9:00-20:00, and the period of sea breeze was21:30-08:00. The main wind direction of sea breeze was WS, the main wind direction of land breeze was NE. The wind speed of land and sea breeze was about the same size, but the sea breeze depth was significantly greater than the land breeze depth, the average depth of the sea breeze was about950m, the average depth of the land breeze was about480m. The height of maximum wind speed increased over time during the period of the sea-land breeze, the maximum wind speed of sea breeze was get at afternoon (about14:00), the maximum wind speed of land breeze was get in the morning (about6:00). |
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