Sudden stratospheric warmings observed in the last decade by satellite measurements

Abstract

In the present study, the influence of sudden stratospheric warming (SSW) that occurred in the last decade (2001/02–2012/13) in the northern hemisphere, simultaneously on the tropopause, stratopause, and mesopause is investigated for the first time using multi-satellite measurements. Multi-satellites include GPS Radio Occultation (GPS RO), Microwave Limb Sounder (MLS) and Sounding of the Atmosphere using the Broadband Emission Radiometry (SABER) onboard the Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) mission. Emphasis have been made to investigate up to what latitudes the effect of SSW will be seen on these pauses. This study also presents the characteristics, intensity and duration of the SSW events. A total of 9 SSW events are identified out of the 12 winters. The altitude of tropopause is observed to have decrease by ~ 0.7 km during SSW events in NH high latitudes and restricted to 60°N and above. As expected, significant increase in the stratopause altitude is noticed, which reaches to almost ~ 80 km when compared to non-warming years and this effect was observed up to 50°N. Thus, SSW effects on the tropopause and stratopause noticed at polar latitudes may not be felt directly at the tropical latitudes. Interestingly, large reduction in the mesopause altitudes (by 3–4 km) is observed during SSW events, which propagates to the tropical latitudes in some of the SSW winters. The gravity wave (GW) activity is also examined during these SSW events.