Temporal and vertical distributions of the occurrence of cirrus clouds over a coastal station in the Indian monsoon region

Abstract. Knowledge of the spatiotemporal coverage cirrus clouds is vital in quantifying radiation budget Earth–atmosphere system. In this paper, we present diurnal and vertical distributions occurrence during different seasons as well interannual variation over Kattankulathur (12.82∘ N, 80.04∘ E) on west coast Bay Bengal. Long-term (2016–2018) continuous micropulse lidar (MPL) observations demonstrate laminar descending that occur either single or multiple layers. The single-layer shows a pattern with frequent late evening (∼ 30 %–40 %), whereas multilayer early morning 10 %–20 %). For cloud occurrences, convective processes dominate pre-monsoon, southwest (SW) monsoon, northeast (NE) monsoon seasons, while freeze-drying process favorable winter season. However, both are dominant occurrences. reaches maximum 40 %) SW NE it minimum 25 indicate confined within tropical tropopause layer (TTL) all seasons. Cirrus rarely occurs above tropopause; however, frequently below TTL extent has broader altitudinal 8–17 km) December–March June–September, narrower April–May 10–17 October–November 9–15 km). also exhibits variations, higher 2016 compared 2017 2018, association El Niño–Southern Oscillation (ENSO).