Investigating the relationship between El Niño Southern Oscillation and cirrus clouds - Preprint

[Geoengineering News]

https://essopenarchive.org/doi/full/10.22541/essoar.177046317.77830770

Authors: Ehsan Erfani

07 February 2026

Abstract 

Cirrus clouds, consisted entirely of ice particles and found at the highest levels of the troposphere, play a critical role in Earth's energy balance. By reflecting incoming sunlight and trapping outgoing longwave radiation, they regulate planetary heating and cooling. Although cirrus clouds cover about a quarter of Earth's surface at any given time, their formation mechanisms and sensitivity to atmospheric variability remain among the least understood in atmospheric science. This project investigates how the El Niño-Southern Oscillation (ENSO), a recurring pattern of ocean warming (El Niño) and cooling (La Niña) in the tropical Pacific, modulates cirrus cloud properties over the Pacific Ocean and parts of the Americas. Leveraging over three decades of NASA satellite observations and reanalysis data, we analyzed changes in cloud and radiation properties such as cloud radiative effects, cloud fraction, and cloud top height under different ENSO phases. We also examined the meteorological conditions such as convection, temperature, moisture, and wind fields to understand the physical mechanisms driving these cloud changes.

Source: ESS Open Archive