Intensification of Precipitation Extremes with Warming in a Cloud-Resolving Model

Abstract

A cloud-resolving model is used to investigate the effect of warming on high percentiles of precipitation (precipitation extremes) in the idealized setting of radiative-convective equilibrium. While this idealized setting does not allow for several factors that influence precipitation in the Tropics, it does allow for an evaluation of the response of precipitation extremes to warming in simulations with resolved rather than parameterized convection. The methodology developed should also be applicable to less idealized simulations. Modeled precipitation extremes are found to increase in magnitude in response to an increase in sea surface temperature. A dry static energy budget is used to relate the changes in precipitation extremes to changes in atmospheric temperature, vertical velocity, and precipitation efficiency. To first order, the changes in precipitation extremes are captured by changes in the mean temperature structure of the atmosphere. Changes in vertical velocities play a secondary role, and tend to weaken the strength of precipitation extremes, despite an intensification of updraft velocities in the upper troposphere. The influence of changes in condensate transports on precipitation extremes is quantified in terms of a precipitation efficiency; it does not change greatly with warming. Tropical precipitation extremes have previously been found to increase at a greater fractional rate than the amount of atmospheric water vapor in observations of present-day variability and in some climate model simulations with parameterized convection. But the fractional increases in precipitation extremes in the cloud-resolving simulations are comparable in magnitude to those in surface water vapor concentrations (owing to a partial cancellation between dynamical and thermodynamical changes), and are substantially less than the fractional increases in column water vapor.

How will orographic precipitation respond to surface warming? An idealized thermodynamic perspective

“…Upstream of the crest, the increase is 8.8%; in the lee, it is 12.2%. By comparison, precipitation from strong nonorographic storms is generally thought to scale with near-surface water vapor [e.g., Trenberth, 1999;O'Gorman and Schneider, 2009;Muller et al, 2011], which increases by 13.1% in our simulations (column-integrated water vapor increases by 19.7%, owing to greater warming aloft). This suggests that in the absence of dynamical changes, orographic precipitation is likely to increase at a lower rate than intense precipitation in nonmountainous regions.…”

Sensitivity of historical orographically enhanced extreme precipitation events to idealized temperature perturbations

“…The same latent heat release can increase the updraft velocity (Sørland et al 2016). Using a cloudresolving model, Muller and O'Gorman (2011) found that changes in vertical velocities tended to weaken the strength of precipitation extremes despite an increase of upper tropospheric updraft velocities for mixed phased clouds in the tropics.…”

Scaling precipitation extremes with temperature in the Mediterranean: past climate assessment and projection in anthropogenic scenarios

“…The CC relation considerably influences the changes in the extreme precipitation intensity under warmer climates (Betts and Harshvardhan 1987;Trenberth et al 2003;Held and Soden 2006;Pall et al 2007;Kharin et al 2007; O' Gorman and Muller 2010;Muller et al 2011;Romps 2011;Westra et al 2014). Considering this, observed relations between extreme precipitation and temperature have received considerable attention.…”