Regional differences in cloud characteristics at different depth, intensity and horizontal scale over South Asia during Indian summer monsoon using CloudSat and reanalysis data

• Published in: Theoretical and applied climatology 2024-12, Vol.155 (12), p.10089-10116
• Main Author: Kumar, Shailendra
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Area; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Climatology; Cloud clusters; Cloud systems; Clouds; Convective systems; Earth and Environmental Science; Earth Sciences; Foothills; Height; Hydrometeors; Meteorological conditions; Monsoons; Precipitation; Radar; Radar data; Radar reflectivity; Rainfall; Reflectance; Spatial distribution; Summer; Summer monsoon; Thresholds; Vertical profiles; Waste Water Technology; Water Management; Water Pollution Control; Wavelength
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-024-05203-2

CloudSat CPR is a mm wavelength (W-band) radar and suitable for measuring the cloud sized hydrometeors. It provides the two-dimensional attenuated corrected radar reflectivity factor (Ze) and cloud mask value to identify the clouds. We used these data to explore the cloud characteristics e.g., their vertical structure, top height at different Ze thresholds, total cloud width, intensity and horizontal span over South Asia during the Indian summer monsoon seasons (June-July–August and September) for the years between 2006 to 2018. We defined four types of the cloud systems based on Ze and height thresholds namely deep convective core (DCC), deep & intense convective systems (DCSs & ICSs), and cloud clusters (CCs). DCCs are the individual CPR vertical profiles, whose tops are crossing 12 km altitude, with base height less than 3 km. CCs are the continuous area of Ze (> -28 dBZ) with no constraint on their base and top height and Ze. DCSs are defined with a minimum cloud base height (CBH  8 km), whereas ICSs consist of atleast on pixel Ze > 10 dBZ in the continuous area of Ze. . The locations and characteristics of the cloud systems vary based on their vertical depth, size and intensity, and characteristics of cloud systems depend the thresholds used in the present study. The major fraction of CCs is concentrated along the north-East part, Himalayan foothills and Indian west coast. However DCCs are mostly observed at head of Bay, Bay of Bengal, Eastern Himalaya Foothills and Gulf of Thailand. DCSs are concentrated at the land dominated and topographic areas and are observed at the Myanmar, land area of north east, Himalayan Foothills, central India and Western Ghats. ICSs are concentrated along the Himalayan foothills and Western Ghats. ICSs have less horizontal span and CTH compared to DCSs, and reveals that in intense precipitation the rainfall is falling down at early stage which do not allow them grow more horizontally and vertically. It is very rare that cloud systems could be large as well as intense over the western side/coast of India compared to eastern side/coast of India, where cloud systems could be intense as well large also. DCSs show that east–west differences in horizontal span but not in CTH, whereas ICSs show the major difference in CTH, not in horizontal span. The oceanic cloud tops are characterized by the cloud sized particles, whereas land and orographic cloud tops are dominated by the precipitat