A search for global atmospheric patterns through principal component analysis on radio occultation data

DE LA TORRE, A.; ALEXANDER, P.; LLAMEDO, P.; BURGOS FONSECA, Y.; HIERRO, R.

Graz

Workshop; OPAC-IROWG 2016; 2016

The GPS Radio Occultation (RO) technique provides diverse atmospheric variables of interest for the study of atmospheric patterns. We analyze the behavior of temperatureand humidity at different levels of pressure obtained from reprocessed GPSRO for the period 2001-2014 grouped and averaged in specific time and space cells. The huge amount of data from 14 years of retrievals urges for the use of a specific method that may be able to locate and extract the most significant information. A principal component analysis (PCA) was first applied in S-mode to determine regions where given time variabilities occurred. Thereafter, PCA was applied in T-mode to extract the temporal evolution of given spatial patterns in the analyzed period. We searched for associations with known patterns as the QBO, ENSO, NAO and others possibly unknown, trying to discard false positive cases. PCA resultsfrom GPSRO were also compared with those from reanalysis data at the selected levels in order to find any significant differences.