Sources of inter-model scatter in TRACMIP, the Tropical Rain belts with an Annual cycle and a Continent Model Intercomparison Project

TL;DR

This study investigates the sources of variability among climate models in predicting surface temperature changes due to quadrupled CO2 levels, using idealized simulations from the TRACMIP project to understand tropical rainfall dynamics.

Contribution

It identifies the fundamental sources of inter-model scatter in tropical climate responses within idealized GCM simulations, enhancing understanding of model differences.

Findings

Inter-model scatter primarily arises from differences in tropical rainfall response.

Idealized simulations help isolate fundamental dynamics affecting climate response.

Results inform improvements in climate model accuracy and reliability.

Abstract

We analyze the source of inter-model scatter in the surface temperature response to quadrupling CO2 in two sets of GCM simulations from the Tropical Rain Belts with an Annual cycle and a Continent Model Intercomparison Project (TRACMIP; Voigt et al, 2016). TRACMIP provides simulations of idealized climates that allow for studying the fundamental dynamics of tropical rainfall and its response to climate change. One configuration is an aquaplanet atmosphere (i.e., with zonally-symmetric boundary conditions) coupled to a slab ocean (AquaCTL and Aqua4x). The other includes an equatorial continent represented by a thin slab ocean with increased surface albedo and decreased evaporation (LandCTL and Land4x).