Regional and seasonal differences of radar reflectivity slopes in lower troposphere in convective and stratiform precipitation using TRMM PR data

• Published in: Theoretical and applied climatology 2024-04, Vol.155 (4), p.2719-2728
• Main Author: Kumar, Shailendra
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Climatology; Convective precipitation; Earth and Environmental Science; Earth Sciences; Echoes; Foothills; Freezing; Height; Lower troposphere; Monsoons; Oceans; Parameter estimation; Precipitation; Radar; Radar data; Radar reflectivity; Rainfall; Reflectance; Seasonal variations; Slope; Slopes; Summer; Summer monsoon; TRMM satellite; Tropical Rainfall Measuring Mission (TRMM); Troposphere; Vertical profiles; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-023-04750-4

Slopes of radar reflectivity below freezing height (FZH) is a critical parameter to estimate the correct rainfall near the surface. TRMM PR-based radar reflectivity slopes are presented here, during Indian and Austral summer monsoon by calculating them in the lower troposphere (< 4 km). Slopes are either positive or negative, which means that the radar reflectivity either decreases (positive slopes) or increases (negative slopes) towards the surface. In the majority of cases, slopes decrease towards the surface over land, but over oceans increase towards the surface. In general, the slopes in convective tropical precipitation are negative where the Arabian Ocean has the highest fraction (~89%) of negative slopes.  However, Bay of Bengal has the highest fraction of positive slopes (~21%). Western Himalaya Foothills has the highest fraction of positive slopes in convective precipitation and shows that ~76% and ~83% of convective and stratiform profiles decrease towards the surface. During the Austral summer monsoon, the Maritime Continent has the highest fraction of negative slopes (~92%) in convective precipitation followed by the Equatorial Indian Ocean. Land vs ocean and regional differences in radar reflectivity slopes are higher in convective precipitation compared to stratiform precipitation. Vertical profiles with extreme positive (>1 dBZ/km) slopes have higher echo top height (ETH) in convective precipitation over the tropical ocean during both the seasons, whereas over land, higher ETHs are associated with negative slopes.