Rayleigh lidar observations of enhanced stratopause temperature over Gadanki (13.5° N, 79.2° E) during major stratospheric warming in 2006

S Sridharan,K Raghunath,Solomon Sathishkumar

doi:10.5194/angeo-27-373-2009

S Sridharan, K Raghunath + Show 1 more

Open Access

https://doi.org/10.5194/angeo-27-373-2009

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Journal: Annales Geophysicae	Publication Date: Jan 22, 2009
Citations: 5	License type: CC BY 3.0

Affiliation: National Atmospheric Research Laboratory

Abstract

Abstract. Rayleigh lidar observations of temperature structure and gravity wave activity were carried out at Gadanki (13.5° N, 79.2° E) during January–February 2006. A major stratospheric warming event occurred at high latitude during the end of January and early February. There was a sudden enhancement in the stratopause temperature over Gadanki coinciding with the date of onset of the major stratospheric warming event which occurred at high latitudes. The temperature enhancement persisted even after the end of the high latitude major warming event. During the same time, the UKMO (United Kingdom Meteorological Office) zonal mean temperature showed a similar warming episode at 10° N and cooling episode at 60° N around the region of stratopause. This could be due to ascending (descending) motions at high (low) latitudes above the critical level of planetary waves, where there was no planetary wave flux. The time variation of the gravity wave potential energy computed from the temperature perturbations over Gadanki shows variabilities at planetary wave periods, suggesting a non-linear interaction between gravity waves and planetary waves. The space-time analysis of UKMO temperature data at high and low latitudes shows the presence of similar periodicities of planetary wave of zonal wavenumber 1.

Highlights

Includes the period of major warming event occurred at high latitudes
The stratopause temperature over the low latitude site, Gadanki (13.5◦ N, 79.2◦ E) suddenly increases on the onset date of the sudden stratospheric warming event occurring at high latitudes
The present study reports the enhancement of stratopause temperature simultaneously with the warming event at high latitude lower stratosphere

Summary

Introduction

A sudden stratospheric warming event is a dramatic event of the high latitude middle atmosphere which involves sudden change of temperature, wind and circulation (Matsuno, 1971; Andrews et al, 1987) and has been observed at mid(Hauchecorne and Chanin, 1983) and high latitudes (Whiteway and Carswell, 1994; Whiteway et al, 1997; Duck et al, 1998; Walterscheid et al, 2000). The daily UKMO temperature data are used to infer the presence of planetary waves at 10◦ N and 60◦ N

Rayleigh lidar temperature data

UKMO data

NCEP data

Results

Discussion and conclusions