Analysis of the Radiative Response of Clouds to El Nino/Southern Oscillation (ENSO) Climate Fluctuations

Texas A&M Research Foundation, College Station TX

Investigators

Abstract

Cloud feedbacks are an important regulator of Earth's climate, as changes in incoming solar and outgoing longwave radiation are expected to have an influence on clouds, and changes in clouds are expected to have further influences on atmospheric radiation. Such feedbacks are the most prominent source of differences between climate model projections of temperature increases due to increased greenhouse-gas concentrations from one model to another. However, the physics and dynamics which determine the sign and strength of cloud feedbacks are not well known, and it is difficult to measure such feedbacks in the real world and determine whether cloud feedbacks in climate models are represented accurately. In this project, cloud feedbacks accompanying El Nino/Southern Oscillation (ENSO) events are examined in observations and model output, so that ENSO events can be used to assess the fidelity of cloud feedbacks, and a better understanding of the factors determining cloud feedbacks can be achieved in a real-world context. Cloud feedbacks are determined from satellite observations, reanalysis products, and climate models, and attention is devoted to determining which meteorological variables are most important in determining the sign and strength of the feedback. The work has broader impacts due to the importance of cloud feedbacks as a source of uncertainty in climate model projections of the extent to which the Earth's temperature will increase due to increasing greenhouse gas concentrations. In addition, the work will support and train a graduate student, thereby promoting the next generation of scientists.