New Study: Water Vapor Heats the Atmosphere Much More Than Aerosols in the Indo-Gangetic Plain

Tech News, New Delhi, January 08, 2026: A significant scientific study has revealed that Water Vapor (WV) plays a much more dominant role in heating the atmosphere over the Indo-Gangetic Plain (IGP) than Aerosols (particulate matter like dust and smoke). This discovery is crucial for refining climate projections and understanding the dynamics of the Indian summer monsoon.

The Research Team & Collaboration

The study was a massive collaborative effort led by premier Indian autonomous institutes under the Department of Science and Technology (DST):

• Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital

• Indian Institute of Astrophysics (IIA), Bengaluru

The research also included international expertise from the University of Western Macedonia (Greece) and Soka University (Japan). The lead researchers included Dr. Umesh Chandra Dumka (ARIES) and Dr. Shantikumar S. Ningombam (IIA), alongside international collaborators Dimitris G. Kaskaoutis, R.E.P. Sotiropoulou, E. Tagaris, and Dr. Pradeep Khatri.

Methodology: How the Data was Gathered

To ensure high accuracy, the team utilized advanced monitoring and simulation tools:

• AERONET Data: Researchers leveraged data from six sites of the Aerosol Robotic Network (AERONET) across the IGP. These are ground-based Sun Photometers that measure aerosol properties with high precision.

• SBDART Modeling: The team employed the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model to run radiative transfer simulations, allowing them to calculate the specific heating rates of different atmospheric components.

Key Findings: The “Clean Air” Paradox

The study, published in the Atmospheric Research Journal, highlights several groundbreaking points:

1. Dominant Heating: Water vapor has a significantly greater impact on atmospheric heating than aerosols do in the densely populated IGP region.

2. Aerosol Interaction: The radiative effect of water vapor is strongly modulated by the presence of aerosols.

3. Intensity in Clean Air: Interestingly, the heating effect of water vapor is much more intense in aerosol-free (clean) atmospheres compared to conditions heavily laden with pollution.

4. Top of the Atmosphere: When aerosols are present, the water vapor effect becomes more noticeable at the top of the atmosphere, highlighting a complex interrelation between the two.

Why It Matters for India

The Indo-Gangetic Plain is a global “hotspot” for aerosol loading. However, this study proves that ignoring the radiative forcing of water vapor leads to inaccurate climate models. By understanding how water vapor and aerosols interact, scientists can now provide more reliable predictions for regional weather patterns and the long-term stability of the Indian climate. – Source: PIB