Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 16, 4497-4509, 2016
https://doi.org/10.5194/acp-16-4497-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
12 Apr 2016
Characteristics of monsoon inversions over the Arabian Sea observed by satellite sounder and reanalysis data sets
Sanjeev Dwivedi1, M. S. Narayanan1, M. Venkat Ratnam2, and D. Narayana Rao1 1Department of Physics, SRM University, Kattankulathur, Chennai, India
2National Atmospheric Research Laboratory (NARL), Gadanki, Tirupati, India
Abstract. Monsoon inversion (MI) over the Arabian Sea (AS) is one of the important characteristics associated with the monsoon activity over Indian region during summer monsoon season. In the present study, we have used 5 years (2009–2013) of temperature and water vapour measurement data obtained from satellite sounder instrument, an Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp satellite, in addition to ERA-Interim data, to study their characteristics. The lower atmospheric data over the AS have been examined first to identify the areas where MIs are predominant and occur with higher strength. Based on this information, a detailed study has been made to investigate their characteristics separately in the eastern AS (EAS) and western AS (WAS) to examine their contrasting features. The initiation and dissipation times of MIs, their percentage occurrence, strength, etc., has been examined using the huge database. The relation with monsoon activity (rainfall) over Indian region during normal and poor monsoon years is also studied. WAS ΔT values are  ∼  2 K less than those over the EAS, ΔT being the temperature difference between 950 and 850 hPa. A much larger contrast between the WAS and EAS in ΔT is noticed in ERA-Interim data set vis-à-vis those observed by satellites. The possibility of detecting MI from another parameter, refractivity N, obtained directly from another satellite constellation of GPS Radio Occultation (RO) (COSMIC), has also been examined. MI detected from IASI and Atmospheric Infrared Sounder (AIRS) onboard the NOAA satellite have been compared to see how far the two data sets can be combined to study the MI characteristics. We suggest MI could also be included as one of the semipermanent features of southwest monsoon along with the presently accepted six parameters.

Citation: Dwivedi, S., Narayanan, M. S., Venkat Ratnam, M., and Narayana Rao, D.: Characteristics of monsoon inversions over the Arabian Sea observed by satellite sounder and reanalysis data sets, Atmos. Chem. Phys., 16, 4497-4509, https://doi.org/10.5194/acp-16-4497-2016, 2016.
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Short summary
Monsoon inversion (MI) over the Arabian Sea is one of the important characteristics associated with the monsoon activity over Indian region. The initiation and dissipation times of MI, their percentage of occurrence, strength etc., has been examined. We suggest MI could also be included as one of the semi-permanent features of southwest monsoon.
Monsoon inversion (MI) over the Arabian Sea is one of the important characteristics associated...
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