INVESTIGADORES
ALEXANDER Pedro Manfredo
congresos y reuniones científicas
Título:
A filtering method to improve the global gravity wave activity calculation in the troposphere and stratosphere from radio occultations
Autor/es:
ALEXANDER, P.; DE LA TORRE, A.; LLAMEDO, P.; HIERRO, R.; SCHMIDT, T.; WICKERT, J.; HASER, A.
Lugar:
Taipei
Reunión:
Congreso; 5th FORMOSAT-3/COSMIC Data Users Workshop and International Conference on GPS Radio Occultation; 2011
Institución organizadora:
National Space Organization (Taiwan)
Resumen:
Reliable estimations of global gravity wave activity
from GPS radio occultations are needed in order to obtain realistic climatologies.
We study the global tropospheric and stratospheric
gravity wave activity by the calculation of the specific potential energy
derived from GPS radio occultation data, as retrieved by COSMIC low Earth orbit
satellites between 2006 and 2010. Systematic annual and interannual features as
a function of longitude, latitude and time are shown. Possible artifacts produced
by the temperature data processing around the tropopause due to the sharp
change in lapse rate are remarked. Our work aims an improvement in the
extraction of the perturbation components of the individual measured profiles. Different
filtering options were tested. A new double filtering procedure that
considerably reduces a systematically observed bias in the gravity
wave activity around the tropopause in standard filtering methods is presented.
After applying a bandpass filter, the perturbation component is processed again
with a low pass filter. The suggested method was tested with synthetic
perturbation components added to known background temperature profiles. It was found
that the performance of the other filtering methods that were used was lower. The
new climatologies were compared with previous ones in order to assess the
changes implied by the new filtering method. The possible improvements may
allow the inclusion of waves with longer vertical wavelengths in future
calculations along the troposphere and stratosphere.