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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L16703, doi:10.1029/2007GL030525, 2007

Will moist convection be stronger in a warmer climate?

Anthony D. Del Genio

NASA Goddard Institute for Space Studies, New York, New York, USA


Mao-Sung Yao

NASA Goddard Institute for Space Studies, New York, New York, USA
Sigma Space Partners, LLC, New York, New York, USA


Jeffrey Jonas

NASA Goddard Institute for Space Studies, New York, New York, USA
Columbia University, New York, New York, USA


Abstract

The intensity of moist convection is an important diagnostic of climate change not currently predicted by most climate models. We show that a simple estimate of the vertical velocity of convective updrafts in a global climate model reproduces observed land-ocean differences in convective intensity. Changes in convective intensity in a doubled CO2 simulation are small because the tropical lapse rate tends to follow a moist adiabatic profile. However, updrafts strengthen by ∼1 m s−1 with warming in the lightning-producing regions of continental convective storms, primarily due to an upward shift in the freezing level. For the western United States, drying in the warmer climate reduces the frequency of lightning-producing storms that initiate forest fires, but the strongest storms occur 26% more often. For the central-eastern United States, stronger updrafts combined with weaker wind shear suggest little change in severe storm occurrence with warming, but the most severe storms occur more often.

Received 27 April 2007; accepted 19 July 2007; published 17 August 2007.

Keywords: convection; updrafts; lightning.

Index Terms: 3314 Atmospheric Processes: Convective processes; 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513); 3324 Atmospheric Processes: Lightning; 3337 Atmospheric Processes: Global climate models (1626, 4928).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 544553 bytes)

Citation: Del Genio, A. D., M.-S. Yao, and J. Jonas (2007), Will moist convection be stronger in a warmer climate?, Geophys. Res. Lett., 34, L16703, doi:10.1029/2007GL030525.