| Popis: |
For the purposes of detailed horizontal and vertical wind field analysis, monthly-mean wind fields were derived from radio occultation (RO) measurements. The wind fields were validated in comparison with European Centre for Medium-Range Weather Forecasts ERA5 reanalysis data.For estimating wind fields outside of the tropics, the geostrophic wind approximation was used. In equatorial regions, due to the Quasi-Biennial Oscillation, thermal wind balance could be used to estimate mean (zonal) stratospheric winds. For both approximations, wind fields were derived from monthly-mean geopotential height fields on isobaric surfaces with 2.5°x2.5° horizontal resolution, in the period from 2007 to 2020.We examined the geographic and vertical range of validity of both approximations for wind field derivation by inter-comparing to the ‘true’ ERA5 wind data. Evaluating the systematic and random aspects of differences, we investigated in which regions the RO-derived geostrophic and thermal wind balances hold reasonably well (within ±2 m/s accuracy) and otherwise break down. Also, a long-term data record validation between RO and ERA5 winds was performed, analyzing the consistency of the approximate and ‘true’ wind fields at the decadal time scale |
