Parametric Sensitivity of Hemispheric Albedo Symmetry Weakly Constrains Shortwave Cloud Radiative Feedbacks in the Community Atmosphere Model Version 6
Year: 2025
Type: article
Abstract: Earth's albedo is symmetric between the northern and southern hemispheres (NH and SH, respectively) because SH clouds compensate for higher NH clear‐sky albedo, a feature that climate models have difficulty capturing. We assess how parameterized processes affect a model's cloud albedo and albedo symmetry using a perturbed parameter ensemble (PPE) of atmospheric simulations. Parameters most significant to simulated albedo symmetry impact precipitation, turbulent dissipation, and sea salt aerosol emissions. Constraining the PPE's shortwave cloud feedbacks using the observed albedo symmetry yields a range of +0.61 0.24 W m −2 K −1 (66% confidence), which is stronger than that of the model's control simulation due to parameter settings that lead to greater loss of subtropical low clouds and weaker negative cloud phase feedback. Although these settings would reduce cloud albedo bias compared to the control simulation, we find that albedo symmetry has limited potential as a constraint for cloud feedbacks on its own.
Source: Geophysical Research Letters
DOI: 10.1029/2025gl115948
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $3,190
Awards: Collaborative Research: Evolving Hemispheric Albedo Asymmetry, CLOUDS ARE A CRITICAL PART OF WEATHER AND CLIMATE PREDICTION. UNCERTAINTIES IN CLOUD PROCESSES DOMINATE THE WATER CYCLE AND THE FORMATION OF PRECIPITATION AND EXTREME WEATHER EVENTS. POTENTIAL CHANGES TO CLOUDS IN RESPONSE TO CLIMATE FORCING (CLOUD FEEDBACKS) ARE ALSO THE LARGEST UNCERTAINTY IN OUR UNDERSTANDING OF THE FUTURE EVOLUTION OF THE CLIMATE SYSTEM. WE PROPOSE TO IMPROVE THE REPRESENTATIONS OF CLOUDS AND CLOUD SYSTEMS IN EARTH SYSTEM MODELS (ESMS) FOR BOTH WEATHER AND CLIMATE SCALES. IN PARTICULAR WE WILL FOCUS ON THE REPRESENTATION OF CLOUD MICROPHYSICS IN BOTH DEEP CONVECTIVE CLOUDS CRITICAL FOR THE WATER CYCLE AND LOWER SHALLOW CONVECTIVE CLOUDS THAT ARE IMPORTANT TO CLIMATE SENSITIVITY. THE GOAL IS A SEAMLESS TREATMENT OF CLOUD MICROPHYSICS THAT CAN WORK FOR BOTH WEATHER AND CLIMATE AND INTEGRATE WITH DIFFERENT TURBULENCE SCHEMES FOR DIFFERENT TYPES OF CLOUDS. WE WILL DO THIS JOINTLY IN THE NASA GODDARD EARTH OBSERVATION SYSTEM (GEOS) AND NCAR COMMUNITY EARTH SYSTEM MODEL (CESM). THE GOAL IS A UNIFIED TREATMENT OF CLOUD MICROPHYSICS THAT WILL WORK WITH NON-HYDROSTATIC MODELS DOWN TO CLOUD PERMITTING SCALES. WE WILL BRING TO BEAR ADVANCED EVALUATION TOOLS AND METHODS TO CHARACTERIZE UNCERTAINTY AND PERFORM EVALUATION AGAINST NASA SATELLITE AND SUB-ORBITAL SETS AND WE WILL DELIVER MODEL CODE AND EVALUATION TOOLS TO THE COMMUNITY IN TWO ESMS., Clouds, inter-hemispheric albedo symmetry, and climate stability, G6712788720, G7827550617
OpenAlex ID: W4412663244