The OI 557.7 nm temperature behaviour during winter stratospheric warming events
Abstract
The behaviour of temperature lower thermosphere is considered during minor type stratospheric warming above Northeast Siberia in January-February and March 2000. The temperature measurements were carried out with the Fabry-Perot spectrometer on a thermal broadening of 557.7 nm [OI] emission in moonless nights at optical station Maimaga near Yakutsk (63 N, 129.7 E, geogr.). The spectrometer had an aperture of 140 mm and the telescope with a focal range of 1200 mm, free spectral interval is 0.0104 nm, tool width - 0.0015 nm. Also used the NOAA stratospheric temperature data at levels 50, 10 and 2 mb. A minor stratospheric warming in January-February 2000 began at high heights and it, apparently, enveloped large on thickness layer including lower thermosphere, mesosphere and stratosphere and propagated downwards with decreasing amplitude. The lower thermosphere temperature was raised approximately on 40 K (20 %) in a maximum of warming and was maintained, at least, up to the end of February, though warming to this time already has disappeared. The temperature measurements results show, that the lower thermosphere warming has stopped at the end of February, but in this time the second wave of warming of stratosphere began. It is supposed, that from this moment the penetration the planetary scale wave perturbations in lower thermosphere became impossible, that has led to its monotonic cooling with velocity 8 K/day at absence of other additional sources of a thermal energy. These results allow making a deduction that the planetary scale wave perturbations under certain satisfactory conditions can penetrate up to heights of lower thermosphere.
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E2221I