climate modeling
; energy budget
; global climate
; global warming
; heat flux
; intertropical convergence zone
; meridional circulation
; Northern Hemisphere
; overturn
; precipitation (climatology)
; rainfall
; satellite imagery
; social impact
; Southern Hemisphere
; tropical environment
英文摘要:
Rainfall in the tropics is largely focused in a narrow zonal band near the Equator, known as the intertropical convergence zone. On average, substantially more rain falls just north of the Equator. This hemispheric asymmetry in tropical rainfall has been attributed to hemispheric asymmetries in ocean temperature induced by tropical landmasses. However, the ocean meridional overturning circulation also redistributes energy, by carrying heat northwards across the Equator. Here, we use satellite observations of the Earth's energy budget, atmospheric reanalyses and global climate model simulations to study tropical rainfall using a global energetic framework. We show that the meridional overturning circulation contributes significantly to the hemispheric asymmetry in tropical rainfall by transporting heat from the Southern Hemisphere to the Northern Hemisphere, and thereby pushing the tropical rain band north. This northward shift in tropical precipitation is seen in global climate model simulations when ocean heat transport is included, regardless of whether continents are present or not. If the strength of the meridional overturning circulation is reduced in the future as a result of global warming, as has been suggested, precipitation patterns in the tropics could change, with potential societal consequences.
Department of Atmospheric Sciences, University of Washington, Seattle 98195, United States; International Pacific Research Center, University of Hawaii, Honolulu 96822, United States; Institut Català de Ciències Del Clima, Barcelona 08005, Spain; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan, 689-798, South Korea; Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
Recommended Citation:
Frierson D.M.W.,Hwang Y.-T.,Fučkar N.S.,et al. Contribution of ocean overturning circulation to tropical rainfall peak in the Northern Hemisphere[J]. Nature Geoscience,2013-01-01,6(11)