(Online First)A study of temperature profiles and trends as revealed by COSMIC RO technique and balloon –borne radiosonde instrument

Abstract

This research presents atmospheric temperature profiles and trends retrieved using COSMIC RO techniqueand balloon-borne radiosonde instrument in 2007 and a few cases during 2017. By effectively using ‘wet’ temperatureproduct available at COSMIC Data Analysis and Archive Center (CDAAC) website, an analysis has been made topresent temperature profiles and trends at various regions including, Indian, Taiwan and Japan. A one-to-onecorrespondence is, clearly, seen between temperature profiles retrieved with COSMIC RO and radiosonde instrument. But, few and dominant differences in temperature profiles are found below at an altitude of ~5 km and above aroundtropopause (~16-17 km). The dominant differences found at below ~5km could be due to the inhomogeneousdistribution of humidity present, generally, at the tropical regions, whereas above the tropopause altitudes, differencesmight be due to the ionospheric residual correction as reported by other researchers. Further, temperature monthlytrends at various regions show distinct characteristics including, a sharp temperature inversion up to tropopause altitude. In addition, it is also observed maximum temperatures (peaks) during the northern summer seasons (May, June, July, and August) and minimum temperatures (troughs) during the northern winter seasons (November, December, January, and February) near to the surface of the Earth. Interestingly, although it is generally observed that the tropopausealtitude is located at ~ 16-17 km at various regions, a keen observation reveals that distinct seasonal and latitudinalvariations can be witnessed. With this case study, it may be concluded that the COSMIC RO technique is able toprovide very accurate measurement, which reiterates its importance as a powerful tool to explore the Earth’s atmosphereon the local and global scale.