Long-term observations of gravity wave activity in the lower stratosphere with GPS radio occultation data

97. T. SCHMIDT , A. DE LA TORRE, P. LLAMEDO, P. ALEXANDER, F. LILIENTHAL, C. JACOBI, J. WICKERT

Praga

Congreso; IUGG; 2015

Global gravity wave (GW) parameters (potential energy and vertical flux of absolutehorizontal momentum) are retrieved from GPS radio occultation (RO) data. The ROtechnique uses GPS signals received aboard low Earth orbiting satellites foratmospheric limb sounding. Atmospheric temperature profiles are derived with highvertical resolution whereas the GPS RO technique is sensitive to GWs with smallratios of vertical to horizontal wavelengths. Since 2006 the six-satellite U.S./TaiwanFORMOSAT-3/COSMIC mission delivers about 2000 global distributed radiooccultations daily. This gives the possibility for the determination of absolutemomentum flux (MF) as the most important parameter for the quantification of GWactivity. In this presentation we discuss MF distributions in the lower stratospherederived from closely spatio-temporal RO temperature fluctuation profiles. The resultsfor different seasons are compared with other MF climatologies (e.g. SABER) andlimitations of the method will be addressed. In addition to MF the variability ofpotential energy derived from several RO missions since 2001 will be discussed.