Climatology of the stationary planetary waves seen in the SABER/TIMED temperatures (2002-2007)

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Abstract

[1] The paper focuses on the global spatial structure, seasonal and interannual variability of the stationary planetary waves (SPW) with zonal wavenumber s = 1 (SPW1) and s = 2 (SPW2) derived from the SABER/TIMED temperature measurements for 6 full years (January 2002–December 2007). The monthly mean climatological (multiyear average, 2002–2007) depictions of SPW temperature field extending between 20 and 120 km altitude and ±50° latitude are derived. A special attention is paid to the SPW temperature field in the lower thermosphere where the SPW1 amplifies in May and December–January in the northern hemisphere (NH) and in April–May and November in the southern hemisphere (SH). Amplitudes in both hemispheres are similar in strato-mesosphere; however, in the lower thermosphere SH amplitudes are significantly larger (∼30 K) than those in NH (∼20 K). The NH SPW1 is able to propagate up to 115 km altitude contributing to the winter amplification of the lower thermospheric SPW1, but that from the SH cannot penetrate above ∼90–100 km. In the lower thermosphere (above h = 100 km) mainly trapped SPW signal is observed. The SPW1 are almost out of phase in both hemispheres; the average (2002–2007) phases are ∼100°W in NH and ∼120°E in SH. Strong evidence indicates that auroral heating is a main origin of the lower thermospheric SPW temperature field.

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