09:00 - 10:10
Conference Room
Oral presentations
On the nature of latitudinal distribution of mesospheric temperatures during sudden stratospheric warming events
Ravindra Pratap Singh1, 2, Duggirala Pallamraju1
1Space and Atmospheric Sciences Division, Physical Research Laboratory, Navrangpura, Ahmedabad, India
2Department of Physics, Sardar Patel University, Vallabh Vidyanagar, India

A Near Infrared Imaging Spectrograph (NIRIS) has been developed in-house which measures O2(0-1) and OH(6-2) band nightglow emissions using which the rotational temperatures are derived. NIRIS is being operated from a low-latitude location, Mount Abu (24.60N, 72.80E), in India. NIRIS data revealed significant enhancements in mesospheric temperatures over low-latitudes during the major sudden stratospheric warming (SSW) event of January 2013. This motivated us to carry out detailed investigations to understand the mesospheric temperature distribution over different latitudes during SSW events. In order to do that, we have used satellite-based mesospheric temperature measurements that were obtained from three different instruments namely, Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), Optical Spectrograph and InfraRed Imaging System (OSIRIS) and Solar Occultation For Ice Experiment (SOFIE). The variations in the mesospheric temperatures at different latitudes have been characterized based on northern hemispheric stratospheric temperature enhancements at high-latitudes during SSW periods. Using the long term (2004-2013) analysis of satellite-based measurements, new features, such as the formation of “double-humped” structure in the mesospheric to stratospheric temperature ratios with respect to latitude during major SSW events with two crests over tropical- to mid-latitudes and a trough over the geographic equator has been revealed. In this study a hitherto unknown aspect of the relationship between stratospheric temperatures at high-latitude and mesospheric temperatures at different latitudes has been brought to light. These results strongly support the interactions in stratospheric-mesospheric coupling and high- to low-latitude coupling of mesosphere lower thermosphere regions, especially during SSW events.


Reference:
Fr-AM-1-O-03
Session:
Observations V
Presenter/s:
Ravindra Pratap Singh
Topic:
1) Observed trends and long term variations in the middle atmosphere
Presentation type:
Oral communication 15 min
Room:
Conference Room
Chair/s:
Bernd Funke
Date:
Friday, 23 September 2016
Time:
09:40 - 09:55