A STUDY ON THE IONOSPHERE AND THERMOSPHERE INTERACTION BASED ON NCAR-TIEGCM: DEPENDENCE OF THE INTERPLANETARY MAGNETIC FIELD (IMF) ON THE MOMENTUM FORCING IN THE HIGH-LATITUDE LOWER THERMOSPHERE

摘要: To understand the physical processes that control high-latitude lower thermospheric dynamics, we quantify forces are mainly responsible for maintaining wind system with aid of National Center Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM). Momentum forcing is statistically analyzed in magnetic coordinates, and its behavior respect to magnitude orientation interplanetary field (IMF) further examined. By subtracting values zero IMF from those non-zero IMF, obtained difference winds 1ower thermosphere( > 0.8| |) or negative( IMF- conditions, maximum appearing around -80 latitude. Difference negative positive have an opposite sign similar strength each other. For positive( 0.3125||) conditions noted subauroral latitudes. condition. Those stronger than indicating has a effect on momentum does At higher altitudes(>125 km) primary determine variations tile neutral pressure gradient, Coriolis rotational Pedersen ion drag forces; however, at various locations times significant contributions can be made by horizontal advection force. On other hand, altitudes(108-125 non-rotational Hall winds. altitudes( condition force tends generate warm clockwise circulation downward vertical motion associated adiabatic compress heating polar cap region. it cold anticlockwise upward expansion cooling dawn sector.