Slayt 1 - RTC, Regional Training Centre - Turkey

South-to-North ComponentThis equation determines time changes in the south-to-north component of the windcaused byHorizontal advection of south-to-north windVertical advection of south-to-north windDeviations from geostrophic balance of the west-to-east wind component. Imbalancesbetween the west-to-east pressure gradient force and the Coriolis force acting on thesouth-to-north wind will change the west-to-east windOther physical processes, such as surface friction and turbulent mixing acting on thesouth-to-north wind. The models also include empirical approximations to try to accountfor atmospheric processes that cannot be forecast directly, although some of the effectsare indirect. For example, radiation and convection are applied only to the temperatureand moisture equations and are not included explicitly in the wind forecast equations.However, the changes in temperature at one time will cause changes in the pressuregradient, which in turn will affect the wind at a later timeNote that the two wind components are interrelated -- each is affected by geostrophicimbalances in the other.