The Mixing Height (MH), Convective Condensation Level (CCL), and Convective Available Potential Energy (CAPE) are computed with different methods and we examined whether these parameters can help to discriminate between weak and strong convection. The observational data set contains soundings released from Stony Plain in Alberta and The Pas in Manitoba for the summers of 2006 and 2007. The major findings were: 1) The Mixing Height values computed with the Heffter method were reliable provided the critical inversion criterion was adjusted for Prairie conditions. 2) The Mixing Height values computed with the Moist Mixed layer method were in good agreement with Mixing Heights computed with the Heffter method. 3) The Mixing Height values computed with the Holzworth parcel method were less useful in that often the potential temperature did not decrease with height above the ground. 4) Observed convective cloud base heights tended to be lower than the CCL computed using the surface parcel method, the 50 mb mixed parcel method, and the moist mixed parcel method. 5) The MH, the sounding-based CCL, and the CAPE did not differentiate between weak and strong convection. 6) We derived a new parameter: the difference between the convective cloud base and the Moist Air Mixing Height. This parameter did discriminate between the likely occurrence of strong and weak convection.

No description available.

ABSTRACT Seven air quality basins are classified in Taiwan according to landforms¡Bweather conditions and atmosphere diffusion. The data showed that the percentages of fractional number of days that PSI is greater than 100 (unhealthful) are 11.4%, 10.5% and 15.3% in three parts of Southern Taiwan (including Kaohsiung City, Kaohsiung County and Pintung County) in the years of 1999, 2000and 2001. For Kao-Ping area alone, the percentages of unhealthful days are, 12.1% , 10.7%and 8.2% in recent three years. The air pollutants in ambient air in Kao-Ping area are particulate matter (PM10) and ozone (O3). Particulate matter (PM10) is a primary pollutant and derivative aerosol, the mainly were factory stack¡Bmobile vehicles¡Bconstruction site and emission the surface of the earth. O3 is a secondary pollutant that is generated by its precursors such as hydrocarbons (HC) and nitrogen oxides (NOx) through complex photo-chemical reactions. Accordingly, attention has been shifted to the source and control of ozone in recently years in southern part of Taiwan, instead of PM10 alone. In order to improve the air quality, the deteriorated reason and pollution condition must be understood. The purpose of this proposal is thus to identify the O3 trend variation and weather pattern and mixing height. This proposal contains two parts: Collect the meteorological data (including pressure¡Btemperature¡Bwind velocity¡Bwind direction¡Bhumidity and sunshine time) and air quality data. Then we analyze the relationship between meteorological factors and air quality. Analyze the high O3 episodes based on the characteristics of hourly¡Bmonthly and seasonally data and to investigate the effects of mixing height and Ventilation index on air quality in Kao-Ping area.

The United States has arbitrary weather criteria for a prescribed burn day to happen. This arbitrary criteria gives prescribed-burn managers a limited amount of days they can burn. To solve this, I established a 30-year climatology based on daily mixing height (m). I then calculated burn-day thresholds based on different mixing heights. I found seasonal and spatial patterns of the amount of days that are prescribed burns. Southeastern United States was my study area. A small decrease in threshold values will lead to large increases in prescribed burn days. Digital maps were created to show the spatial variability of prescribed burn days and the effects of lowering thresholds for prescribed burn days. This research will aid policy makers in lessening the criteria for burn days.