Abstract
Abstract. To study the mesospheric temperature inversion, daily temperature profiles obtained from the Halogen Occultation Experiment (HALOE) aboard the Upper Atmospheric Research Satellite (UARS) during the period 1991-2001 over the Indian tropical region (0-30° N, 60-100° E) have been analyzed for the altitude range 34-86km. The frequency of occurrence of inversion is found to be 67% over this period, which shows a strong semiannual cycle, with a maximum occurring one month after equinoxes (May and November). Amplitude of inversion is found to be as high as 40K. Variation of monthly mean peak and bottom heights along with amplitude of inversions also show the semiannual cycle. The inversion layer is detected most frequently in the altitude range of 70-85km, with peak height ranging from 80 to 83km and that of the bottom height from 72 to 74km. A comparison of frequency of temperature inversion with that obtained from Rayleigh lidar observations over Gadanki (13.5° N, 60-100° E) is found to be reasonable. The seasonal variation of amplitude and frequency of occurrence of temperature inversion indicates a good correlation with seasonal variation of average ozone concentration over the altitude range of the inversion layer.
Highlights
The “Thermal Inversion Layer” is a region of enhanced temperature within the upper mesosphere and is frequently observed and reported over the years with a variety of sensing instruments
The Halogen Occultation Experiment (HALOE) temperature data is for the period from October 1991 to September 2001, over the altitude range of 34–86 km with vertical resolution of about 2.3 km, and this data have been analyzed in this study
Results indicate that the frequency of occurrence of temperature inversions over the Indian tropical region is found to be 67% during this period
Summary
1997; Clancy et al, 1989, 1994), etc., have repeatedly detected this mesospheric inversion layer phenomenon. Whiteway et al (1995) reported that inversion layers are associated with an overlying, nearly adiabatic laps rate, which is an indication of a well mixed turbulent layer that is confirmed by a one-dimensional numerical model. Thomas et al (1996) observed the mesospheric structures both above and below the temperature inversion. Later Thomas et al (2001) observed MILs during both night and day, with a downward progression at 0.40±0.06 km/hr with overlying adiabatic lapse rate They correlated the amplitude of inversion with gravity wave activity. Kumar et al (2003) compared Rayleigh lidar temperature profiles with HALOE temperature measurements over the same location at Gadanki They reported that in the mesospheric inversion region of 70–80 km magnitude of temperature data obtained by lidar is about 5–10 K warmer than that of the HALOE data. Nee et al (2002) presented atmospheric temperature profiles from lidar measurements over Taiwan (25◦ N, 121◦ E) and Gadanki (13.5◦ N, 79.2◦ E) and compared them with HALOE profiles They observed the presence of a mesospheric inversion layer in both lidar and HALOE profiles. Present results are compared with the results obtained by other workers over the Indian region
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
