VEGETATION PATTERN OF ISTANBUL FROM THE LANDSAT DATA AND THE RELATIONSHIP WITH METEOROLOGICAL PARAMETERS

This paper discusses the preliminary results of a study on the vegetat ion pattern and its relationship with meteorological parameters in and around Istanbul. The study covers an area of over 6800 km2 consisting of urban and suburban centers, and uses the visible and near-infrared bands of Landsat. The spatial variation of the Normalized Difference Vegetation Index (NDVI) and meteorological parameters such as sensible heat flux, momentum flux, relative humidity, moist static energy, rai nfall rate and temperature have been investigated based on observation s in ten stations in the European (Thracian) and Anatolian parts of Is tanbul. NDVI values have been evaluated from the Landsat data for a si ngle day, viz. 24 October 1986, using ERDAS in ten different classes. The simultaneous spatial variations of sensible heat and momentum flux es have been computed from the wind and temperature profiles using the Monin-Obukhov similarity theory. The static energy variations are bas ed on the surface meteorological observations. There is very good corr elation between NDVI and rainfall rate. Good correlation also exists b etween: NDVI and relative humidity; NDVI, sensible heat flux and relat ive humidity. NDVI, momentum flux and emissivity; and NDVI, sensible h eat flux and emissivity. The study suggests that the momentum flux has only marginal impact on NDVI. Due to rapid urbanization, the coastal belt is characterized by reduced NDVI compared to the interior areas, suggesting that thermodynamic discontinuities considerably influence t he vegetation pattern. This study is useful for the investigation of s mall-scale circulation models, especially in urban and suburban areas where differential heating leads to the formation of heat islands. In the long run, such studies on a global scale are vital to gain accurat e, timely information on the distribution of vegetation on the earth's surface. This may lead to an understanding of how changes in land cov er affect phenomena as diverse as the atmospheric CO2 concentrations, the hydrological cycle and the energy balance at the surface-atmospher e interface.