INVESTIGADORES
DE LA TORRE Alejandro
congresos y reuniones científicas
Título:
A global analysis of gravity wave activity in the upper troposphere and lower stratosphere region derived from GPS radio occultation data
Autor/es:
T. SCHMIDT1, A. DE LA TORRE2, S. HEISE1, AND J. WICKERT1
Lugar:
Montreal, Canada
Reunión:
Congreso; IAMAS MOCA 09; 2009
Resumen:
Global gravity wave (GW) potential energy distributions are retrieved from GPS radio occultation (RO) data from CHAMP for the time period 2001-2008. The RO technique uses GPS signals received aboard low 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. The specific potential energy as a measure of GW activity is usually deduced from the temperature profile for each occultation event up to 35 km. To separate the GWs from the background a band-pass filter associated to different vertical wave lengths is applied to the measured temperature profiles for the complete altitude range. This GW analysis technique introduces significant artificial enhancement of wave activity at the tropopause, mainly in the tropics, depending on the ability of the filter to reproduce the tropopause kink. As an alternative to the usage of the complete temperature profile we discuss a ‘separate method’: the GW analysis is considered for the troposphere and lower stratosphere separately by applying the band-pass filter up to the tropopause and from the tropopause to the end of the temperature profile. This method gives more realistic GW activity in the tropopause region. The specific potential energy derived from the different methods will be discussed globally and error sources will be pointed out. The specific potential energy as a measure of GW activity is usually deduced from the temperature profile for each occultation event up to 35 km. To separate the GWs from the background a band-pass filter associated to different vertical wave lengths is applied to the measured temperature profiles for the complete altitude range. This GW analysis technique introduces significant artificial enhancement of wave activity at the tropopause, mainly in the tropics, depending on the ability of the filter to reproduce the tropopause kink. As an alternative to the usage of the complete temperature profile we discuss a ‘separate method’: the GW analysis is considered for the troposphere and lower stratosphere separately by applying the band-pass filter up to the tropopause and from the tropopause to the end of the temperature profile. This method gives more realistic GW activity in the tropopause region. The specific potential energy derived from the different methods will be discussed globally and error sources will be pointed out.