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Seasonal variability of low, mid, and high level cloud properties over southern Western Ghats, India: a lidar ceilometer analysis.

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Title: Seasonal variability of low, mid, and high level cloud properties over southern Western Ghats, India: a lidar ceilometer analysis.
Authors: Pramitha, M.1 (AUTHOR) pramitha@iisertvm.ac.in, Aathira, K. P.1,2 (AUTHOR), Riya Raju, K.1,2 (AUTHOR)
Source: International Journal of Remote Sensing. Jan2026, Vol. 47 Issue 1, p266-287. 22p.
Subjects: Ceilometer, Monsoons, Attenuation coefficients, Seasonal temperature variations, Cloud droplets
Geographic Terms: Western Ghats (India), India
Abstract: The influence of clouds and their vertical structures on the radiative budget, hydrological cycle, and climate is significant, yet its quantification remains uncertain. Present study utilizes ceilometer data from August 2023 to October 2024, and performed the first comprehensive study of low, mid, and high level clouds Cloud Base Height (CBH) and Linear Depolarization Ratio (LDR) over the Southern Western Ghat region, Vithura. In the present study, CBH were categorized as low-level clouds (LLC < 2 km), mid-level clouds (MLC, 2–6 km), and high level clouds (HLC > 6 km). CBH and LDR observations were aggregated into 1 hour bins, with periods containing precipitation for more than 60% of the time excluded from the analysis to minimize the impact of signal attenuation. Overall cloud occurrence (including low, mid and high level clouds) peaks in the Monsoon season (87.3%), followed by post monsoon (84%), pre-monsoon season (59%) and minimum occurrence during winter season (55%). During the monsoon, moisture-rich southerly winds from the Arabian Sea interact with the Western Ghats and produce abundant cloud cover. In the post monsoon, reduced but adequate humidity sustains notable cloud formation. Winter clouds arise mainly from orographic lifting, while in the pre monsoon, high surface heating with limited moisture favours dry convection, resulting in reduced cloudiness. Diurnal variations of CBH of LLC shows that in every season, the average CBH rises substantially during the daytime but in case of MLC and HLC, the mean CBH exhibit a noticeable decrease during the daytime hours, observation of HLC in the daytime is very less, this shows the inability of Ceilometer to detect HLC because of signal attenuation. Also the LDR analysis of each cloud type obeys the well-established understanding that hydrometeors transition from liquid raindrops to ice crystals as cloud altitude increases. KEY POINTS: First time ceilometer observation over a southern Western Ghat region of India, Vithura. In each season, both MLC's and HLC's mean CBH exhibit a noticeable decrease in cloud base height during the daytime hours. LDR values increase with CBH with a clear daytime enhancement. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:The influence of clouds and their vertical structures on the radiative budget, hydrological cycle, and climate is significant, yet its quantification remains uncertain. Present study utilizes ceilometer data from August 2023 to October 2024, and performed the first comprehensive study of low, mid, and high level clouds Cloud Base Height (CBH) and Linear Depolarization Ratio (LDR) over the Southern Western Ghat region, Vithura. In the present study, CBH were categorized as low-level clouds (LLC < 2 km), mid-level clouds (MLC, 2–6 km), and high level clouds (HLC > 6 km). CBH and LDR observations were aggregated into 1 hour bins, with periods containing precipitation for more than 60% of the time excluded from the analysis to minimize the impact of signal attenuation. Overall cloud occurrence (including low, mid and high level clouds) peaks in the Monsoon season (87.3%), followed by post monsoon (84%), pre-monsoon season (59%) and minimum occurrence during winter season (55%). During the monsoon, moisture-rich southerly winds from the Arabian Sea interact with the Western Ghats and produce abundant cloud cover. In the post monsoon, reduced but adequate humidity sustains notable cloud formation. Winter clouds arise mainly from orographic lifting, while in the pre monsoon, high surface heating with limited moisture favours dry convection, resulting in reduced cloudiness. Diurnal variations of CBH of LLC shows that in every season, the average CBH rises substantially during the daytime but in case of MLC and HLC, the mean CBH exhibit a noticeable decrease during the daytime hours, observation of HLC in the daytime is very less, this shows the inability of Ceilometer to detect HLC because of signal attenuation. Also the LDR analysis of each cloud type obeys the well-established understanding that hydrometeors transition from liquid raindrops to ice crystals as cloud altitude increases. KEY POINTS: First time ceilometer observation over a southern Western Ghat region of India, Vithura. In each season, both MLC's and HLC's mean CBH exhibit a noticeable decrease in cloud base height during the daytime hours. LDR values increase with CBH with a clear daytime enhancement. [ABSTRACT FROM AUTHOR]
ISSN:01431161
DOI:10.1080/01431161.2025.2593713