ANALYSIS OF ATMOSPHERIC BOUNDARY LAYER AND LAKE-LAND INTERACTION

Abstract

This study focuses on water and energy balance over the Central Anatolian's Lake Area. Analysis of meteorological parameters recorded in the atmospheric boundary layer with an instrumented aircraft (Vilga) during the measuring campaign between 29 and 31 August, 1999 are presented in this project. This paper presents some defiled results on 30 August 1998. Measurements are carried out over the Lake Egirdir (Latitude: 37.8 and 38.4 N, Longitude: 38.3 and 31.4 E, Altitude: 919m (msl)) and near vicinity of Central Anatolia. Sampling interval of measurements is one second. All flight and meteorological data is automatically recorded. Time variations of pressure (P), air temperature (Ta), Surface temperature (Ts), relative humidity (RH), turbulent fluxes of heat (SH) and moisture (LH) measured over the lake area are analyzed with respect to the distribution with height and horizontal scale, intercorrelation and relation to synoptic weather systems. Air temperature values change in the range of 25C and 35C. Lower values of air temperature (25C) are recorded over the Lake Egirdir during measuring campaign. Relative humidity values increases to 40% over the lake surface. Air pressure values are between 800hPa and 900hPa. Convective motions and turbulence are observed between 11:00am and 2:00pm. Surface temperature values change between 25C and 35C in late moming. Their range is between 30C and 55C afternoon. Deviations of temperature and relative humidity values from the averages are higher over land area. Mean value of lake surface temperature is 17C in the moming and 20.5C in the aftemoon. Effects of spatial and vertical variation of meteorological parameters on dry and wet convection are presented in this study. During the last measuring campaign beginning from 11:00am developing convective clouds cause some decreasing trend over temperature values. Flight measurements are reanalyzed together with boat measurements and conventional surface data over the lake and near vicinity of it. Spatial and time variation of flux values. Bowen Ratio (SH/LH), Ri Number and Monin Obukhov Length are analyzed to define the lake surface effects on convective activities over the study area. The role of fluxes on moisture balance is discussed.