Sensitivity of Tropical Extreme Precipitation to Surface Warming in Aquaplanet Experiments Using a Global Nonhydrostatic Model

Abstract

Increases of atmospheric water vapor holding capacity with temperature (7% K −1 -8% K −1 , CC-rate) can lead to increasing extreme precipitation (EP). Observations show that tropical EP has increased during the last five decades with a rate higher than in the extratropics. Global climate models (GCM's) diverge in the magnitude of increase in the tropics, and cloud-resolving models (CRM's) indicate correlations between changes in tropical EP and organization of deep convection. We conducted globalscale aquaplanet experiments at a wide range of resolutions with explicit and parameterized convection to bridge the gap between GCM's and CRM's. We found increases of tropical EP beyond the CC rate, with similar magnitudes when using explicit convection and parametrized convection at the resolution it is tuned for. Those super-CC rates are produced due to strengthening updrafts where extreme precipitation occurs, and they do not exhibit relations with changes in convective organization. Plain Language Summary Theory and observations indicate tropical extreme precipitationmight increase with global warming. Projections from climate models agree on increases in the extratropics, but not in the tropics. More idealized simulations indicate links between increases of tropical extreme precipitation and changes in the spatial organization of the meteorological systems producing those extremes. Using a novel model approach, we found that tropical extreme precipitation increases with warming more than expected due to increases in the dynamics of the extreme precipitation systems, whereas changes in the spatial organization have a small role.

Sensitivity of Tropical Extreme Precipitation to Surface Warming in Aquaplanet Experiments Using a Global Nonhydrostatic Model

“…The primary data for this study, that is, the ICON-A model is described in Giorgetta et al (2018) and its source code and components are available on https://mpimet.mpg.de/en/science/modeling-with-icon/ code-availability. The configuration scripts to run the model, the data and scripts to reproduce the figures can be found in Uribe et al (2020)…”

“…The configuration scripts to run the model, the data and scripts to reproduce the figures can be found in Uribe et al. (2020).…”

Early Development and Tuning of a Global Coupled Cloud Resolving Model, and its Fast Response to Increasing CO2

“…With the advent of computers such simulations became applicable to both weather forecasting and climate modeling in the 1950's and 1960's (Charney et al, 1950;Bolin, 1955;Phillips, 1956;Manabe et al, 1965;Manabe and Bryan, 1969). A limitation of climate modeling is that important small scale motions, not resolved by the computational grid, must be parameterised which is a leading source of uncertainty and a limitation to our ability to understand the results (Hohenegger and Stevens, 2018;Retsch et al, 2019;Hohenegger et al, 2020;Uribe et al, 2021). In this paper we describe the development of a coupled climate model with sufficient resolution to represent atmospheric moist convection, gravity wave drag and ocean eddies and so can dispose of their parameterisations (Figure 1).…”

“…There is vast experience that this approach can be fruitful from studies of limited area simulations, or stand alone atmosphere or ocean models (e.g. Deardorff, 1970;Klemp and Wilhelmson, 1978;Smith et al, 2000;Tomita et al, 2005;Heinze et al, 2017;Stevens et al, 2019;Retsch et al, 2019;Uribe et al, 2021). In particular horizontal ocean eddies, moist convection and various forms of gravity wave drag are for the most part parameterised in contemporary climate models, but at kilometer scale resolutions the effect of these processes can largely be represented by resolved motion.…”