The Study of Near-surface wind and pollution characteristics in Yuxi Center District

The pilot balloon observation system with dual theodolite was used to investigate the effect of near-surface wind characteristics on pollutant diffusion in Yuxi NO.1 middle school, and by using the meteorological observation data analysis of the different weather characteristic and the impact on the pollutant concentration distribution. The experimental results showed that the predominant wind direction was not so apparent due to the affection of channels to the wind and the valley of the wind. During the observation, the regional atmospheric stability is more unstable and neutral stability, and longer duration of neutral stability would not be good at contamination diffusion. Winds profile observed four types of irregular, reverse, extreme value, normal. Under neutral stability conditions, the degree of fitting of wind profile exponent P in normal-type wind velocity is good, and its value is 0.608. The mountain-valley wind relates to daily range of temperature and the greater this difference in temperature is, the more frequency of mountain-valley wind blowing. In the morning and evening is the transition of mountain-valley wind, the period of time due to wind direction changes, causing the circulate accumulation of the pollutants in the air over the city. (paper)