Regional cloud analysis finds stronger monsoon-season atmospheric warming

A regional analysis of atmospheric cloud radiative effects across India, the North Indian Ocean and adjacent areas found that clouds produced net atmospheric warming in every season, with the largest effects during the monsoon. For 2000–2024, maximum net atmospheric cloud radiative effect (NCREA) was estimated at about 55 W/m² in a monsoon-dominated region and 23 W/m² in an “other region.” The study associated the particularly strong monsoon values with the dominance of high clouds. These results describe modeled and satellite-derived regional estimates rather than direct measurements at every location, and the supplied abstract does not report uncertainty ranges for the main trend estimates.

The analysis combined three gridded data products: ERA5 cloud-cover data at 0.25° × 0.25° resolution, ISCCP cloud-cover data at 1° × 1° resolution, and CERES EBAF Edition 4 radiation and cloud-properties data at 1° × 1° resolution. The Indian and adjacent regions, including the North Indian Ocean, were divided into monsoon-dominated and other areas. Across both subregions and all seasons, the calculated net effect indicated atmospheric warming and was dominated by the long-wave cloud radiative effect (LWCREA).

Monsoon-season NCREA reached approximately 55 W/m² in the monsoon-dominated region and 23 W/m² in the other region, the highest values reported for the respective subregions. The study attributed this seasonal maximum to the dominance of high clouds. The relationship between high-cloud cover and LWCREA was also quantified: a 1% increase in high-cloud cover was associated with increases of 0.86 W/m² in LWCREA over the monsoon-dominated region and 0.81 W/m² over the other region.

These are statistical associations in the analyzed regional data, and the supplied evidence does not establish a separate causal mechanism for the long-term trends. Interannual changes differed between the two areas. In the other region, NCREA had a significant estimated net-warming trend of 0.09 W/m² per year, associated with increasing cloud cover, particularly clouds with higher tops.

The monsoon-dominated region instead showed a significant decrease in net warming of 0.07 W/m² per year. Cloud cover and cloud properties there did not follow the same decreasing trend. The opposing trend directions show that the average behavior over the full study domain depends on which subregion is examined: a broadly warming NCREA trend outside the monsoon-dominated area coexisted with declining net warming within it.

The study is a multidecadal regional analysis constrained by the coverage, spatial resolution and record length of its input products. ERA5 provided higher-resolution cloud-cover information than the 1° × 1° ISCCP and CERES EBAF data, while the interpretation of interannual changes relied on relationships among cloud cover, cloud properties and radiation. The reported evidence does not provide uncertainty ranges, mechanism-specific short-wave contributions or a complete causal account of the differing trends.

Even so, the results offer a consistent quantitative picture: clouds had a calculated net warming influence throughout the seasons, the influence peaked during the monsoon, and long-term NCREA trends changed sign between the monsoon-dominated and other regions. The analysis also links the strongest LWCREA values to high-cloud cover, with similar 1% sensitivity estimates in the two subregions despite their contrasting multi-year trends.

Subject of Research: Spatiotemporal cloud radiative effects over India, the North Indian Ocean and adjacent regions

Article Title: Spatiotemporal variations of atmospheric cloud radiative effects over the Indian and adjacent regions

Article References: Naskar, P. R., & Singh, G. P. (2026). Spatiotemporal variations of atmospheric cloud radiative effects over the Indian and adjacent regions. Theoretical and Applied Climatology, 157(11), Article 735. https://doi.org/10.1007/s00704-026-06668-z

Image Credits: AI Generated

DOI: 10.1007/s00704-026-06668-z

Keywords: atmospheric cloud radiative effects, Indian monsoon, North Indian Ocean, high-cloud cover, long-wave radiation, ERA5, CERES EBAF, ISCCP, regional climate, spatiotemporal trends, Spatiotemporal, variations