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

SCHMIDT TORSTEN; FAVER, ANTONIA; DE LA TORRE ALEJANDRO; LLAMEDO PABLO; ALEXANDER PEDRO; WICKERT JENS

QUEENSTOWN

Congreso; SPARC 2014; 2014

SPARC (Stratosphere-troposphere Processes And their Role in Climate)

Global gravity wave (GW) parameters (potential energy and vertical flux of absolute horizontal momentum) are retrieved from GPS radio occultation (RO) data. The RO technique uses GPS signals received aboard low Earth orbiting satellites for atmospheric limb sounding. Atmospheric temperature profiles are derived with high vertical resolution. The GPS RO technique is sensitive to GWs with small ratios of vertical to horizontal wavelengths. Since 2006 the six-satellite U.S./Taiwan FORMOSAT-3/COSMIC mission delivers about 2000 global distributed radio occultations daily. This gives the possibility for the determination of absolute momentum flux (MF) as an important parameter for the quantification of GWs to the atmospheric circulation. In this presentation we discuss MF distributions in the lower stratosphere derived from triples of spatio-temporal nearby temperature fluctuation profiles for different seasons. The results are compared with other MF climatologies. Possibilities and limitations of the method will be addressed. In addition to the MF results long-term climatologies and trends of the potential energy and vertical wavelengths derived from several RO missions since 2001 will be presented.