New Study Reveals Significant Below-Cloud Evaporation During Indian Monsoon
A recent study published in Atmospheric Chemistry and Physics has investigated the phenomenon of below-cloud evaporation during the Indian summer monsoon. The research, conducted in Pune on the leeward side of the Western Ghats, utilized stable water isotopes to track the journey of raindrops from cloud to ground. Scientists found that not all raindrops reach the surface intact; a significant portion evaporates as they fall through warmer, drier air. The study estimated that, on average, 23% of rainwater mass evaporated between the cloud base and the ground. This evaporation rate varied considerably between individual storms, ranging from 4% to 61%, primarily influenced by atmospheric temperature, relative humidity, and rainfall intensity. The isotopic signatures of hydrogen and oxygen in rainwater provided clear evidence of this otherwise invisible process, as lighter isotopes evaporate more readily, leaving the remaining water enriched in heavier isotopes.
