scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
All-sky imaging observation of interacting mesospheric frontal systems
Narayanan Viswanathan Lakshmi, Gurubaran Subramanian
Equatorial Geophysical Research Laboratory, Indian Institute of Geomagnetism
On the night of February 8, 2007, mesospheric OH imaging observations from low
latitude Indian site, Tirunelveli (8.7 o N, 77.8 o E), revealed development of a frontal system
moving approximately towards North (designated as Front 1). About an hour later, it collided
with another frontal system (Front 2). Front 2 had entered from northwest and was moving
towards Southeast. The collision also involved a third frontal system (Front 3) which was
relatively weaker and moving almost exactly opposite to front 1. Interestingly, the measured
wavelengths and time periods indicate a loss of energy for Front 1 and gain of energy for the
other two systems. Especially the parameters appear to get almost exchanged between front 1
and front 2. The background wind information revealed wind reversal during the event. The
temperature information obtained approximately two hours before the interaction of fronts
from SABER snapshot measurements shows an inversion layer partially covering the OH
emission heights. In this work an attempt is made to understand the event. This is a very rare
observation that appears analogous to collision of particles. Hence, understanding of such
events is expected to improve our conceptions on the different types of atmospheric wave
processes and their interactions especially at high frequency limit.