Diurnal Variation of the Lower Tropospheric Water Vapor Observed Using Microwave Radiometer Over Darjeeling (27.05°N, 88.26°E)

  • Shyam MehtaEmail author
  • Soumendra Singh
  • Amitabha Mitra
  • Sanjay K. Ghosh
  • Sibaji Raha
Research Article


In this paper, diurnal variation in tropospheric water vapor is studied using two instruments, namely water vapor (WV) radiometer (WVR-1100) and micro rain radar (MRR-2). It is observed that the WV and RH are maximum during wet hours while minimum during dry hours. The mean diurnal variation of WV shows greater value in the wet period due to high evaporation and convection rates. In addition, frequent saturation of WV leads to phases change and occurrence of precipitation in the wet periods. During the dry periods (October to March), the WV does not reach its saturation level observe to be varying from month to month. WV increases by 2 cm, while RH changes from 80 to 100%. In all seasons, the mean diurnal variation of the WV shows maximum value during daytime and minimum value during nighttime. Hence, mean diurnal water vapor cycle which is driven by thermally induced circulation from valley to mountain region shows RH near saturation level (~ 100%) throughout the active spells of the rainfall over Darjeeling.


Microwave radiometer Relative humidity Water vapor Rainfall 



This work was fully supported by Intensification of Research in High Priority Area (IRHPA), Department of Science and Technology (DST), Govt. of India. We thank technical team members for the IRHPA project at Bose Institute for taking the MRR and WVR observation. The first author (SM) is thankful to DST for providing the fellowship under IRHPA Project.


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Copyright information

© Indian Society of Remote Sensing 2018

Authors and Affiliations

  1. 1.Physics, Center for Astroparticle Physics and Space ScienceBose InstituteKolkataIndia

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