Effect of Urban Expansion Indices Change by (R.S.) on Height of Convective Radix Layer around Baghdad Airport (Iraq)
Keywords:Built Up Index, Radix Layer, Convective Layer, Remote Sensing, Baghdad
Change in structure of land surface can affect atmospheric boundary layer and formation of internal boundary layer. This will change shear stresses and turbulent boundary layer. Change in low level wind shear and turbulent can affect air craft performance and has potentially adverse effects on flight safety during landing and taking-off stages. In this study, change in land area around Baghdad Airport and its effects on structure of boundary layer and radix layer through summer season (July from years 1985 and 2014) is examined. The examination is done through atmospheric data of radiosonde (at altitude more than 1500 m) and remote sensing by Landsat 5 and 8 images (circular region around airport has radius 3.250 km and the airport is considered the center of this circle). From analysis of hourly wind speed and temperature profile with height observed by radiosonde, change in convective radix layer can be determined at this period resulted from change structure of boundary layer depending on characteristic of landcover used in supervised classification. Building area increases from 18% in 1985 to 41% in 2014. These results enforced by positive values of built up index BI, that showed a decreases in 2014. All these elements changed convective radix layer from less than 500 m in summer 1985 to more than 700 m. There is a large fluctuation in radix layer height depended on convective and friction velocity at 2014 data. Thus indirect change in structure of convective layer will affect navigation movement of Baghdad International Airport.