Atmosphere (Feb 2022)

Observed Climatology and Trend in Relative Humidity, CAPE, and CIN over India

  • Pathan Imran Khan,
  • Devanaboyina Venkata Ratnam,
  • Perumal Prasad,
  • Ghouse Basha,
  • Jonathan H. Jiang,
  • Rehana Shaik,
  • Madineni Venkat Ratnam,
  • Pangaluru Kishore

DOI
https://doi.org/10.3390/atmos13020361
Journal volume & issue
Vol. 13, no. 2
p. 361

Abstract

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Water vapor is the most dominant greenhouse gas in the atmosphere and plays a critical role in Earth’s energy budget and hydrological cycle. This study aims to characterize the long-term seasonal variation of relative humidity (RH), convective available potential energy (CAPE), and convective inhibition (CIN) from surface and radiosonde observations from 1980–2020. The results show that during the monsoon season, very high RH values are depicted while low values are depicted during the pre-monsoon season. West Coast stations represent large RH values compared to other stations throughout the year. Irrespective of the season, the coastal regions show higher RH values during monsoon season. Regardless of season, the coastal regions have higher RH values during the monsoon season. During the pre-monsoon season, the coastal region has high RH values, whereas other regions have high RH values during the monsoon season. The rate of increase in RH in North-West India is 5.4%, followed by the West Coast, Central, and Southern parts of India. An increase in water vapor leads to raised temperature, which alters the instability conditions. In terms of seasonal variation, our findings show that CAPE follows a similar RH pattern. CAPE increases sharply in Central India and the West Coast region, while it declines in South India. Opposite features are observed in CIN with respect to CAPE variability over India. The results of the study provide additional evidence with respect to the role of RH as an influencing factor for an increase in CAPE over India.

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