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contributor authorZelinka, Mark D.
contributor authorGrise, Kevin M.
contributor authorKlein, Stephen A.
contributor authorZhou, Chen
contributor authorDeAngelis, Anthony M.
contributor authorChristensen, Matthew W.
date accessioned2019-09-19T10:01:25Z
date available2019-09-19T10:01:25Z
date copyright7/20/2018 12:00:00 AM
date issued2018
identifier otherjcli-d-18-0114.1.pdf
identifier urihttp://yetl.yabesh.ir/yetl1/handle/yetl/4260695
description abstractAbstractThe long-standing expectation that poleward shifts of the midlatitude jet under global warming will lead to poleward shifts of clouds and a positive radiative feedback on the climate system has been shown to be misguided by several recent studies. On interannual time scales, free-tropospheric clouds are observed to shift along with the jet, but low clouds increase across a broad expanse of the North Pacific Ocean basin, resulting in negligible changes in total cloud fraction and top-of-atmosphere radiation. Here it is shown that this low-cloud response is consistent across eight independent satellite-derived cloud products. Using multiple linear regression, it is demonstrated that the spatial pattern and magnitude of the low-cloud-coverage response is primarily driven by anomalous surface temperature advection. In the eastern North Pacific, anomalous cold advection by anomalous northerly surface winds enhances sensible and latent heat fluxes from the ocean into the boundary layer, resulting in large increases in low-cloud coverage. Local increases in low-level stability make a smaller contribution to this low-cloud increase. Despite closely capturing the observed response of large-scale meteorology to jet shifts, global climate models largely fail to capture the observed response of clouds and radiation to interannual jet shifts because they systematically underestimate how sensitive low clouds are to surface temperature advection, and to a lesser extent, low-level stability. More realistic model simulations of cloud?radiation?jet interactions require that parameterizations more accurately capture the sensitivity of low clouds to surface temperature advection.
publisherAmerican Meteorological Society
titleDrivers of the Low-Cloud Response to Poleward Jet Shifts in the North Pacific in Observations and Models
typeJournal Paper
journal volume31
journal issue19
journal titleJournal of Climate
identifier doi10.1175/JCLI-D-18-0114.1
journal fristpage7925
journal lastpage7947
treeJournal of Climate:;2018:;volume 031:;issue 019
contenttypeFulltext


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