Has Arctic Warming Impacted Mid-latitude Atmospheric Circulation?

Has Arctic Warming Impacted Mid-latitude Atmospheric Circulation?

Arctic observations and model simulations have shown enhanced warming in the Arctic under increasing greenhouse gases, a phenomenon known as Arctic amplification (AA), is caused by sea-ice loss. With warmer temperatures affecting the Arctic, meridional temperature gradients have weakened, thus affecting general atmospheric circulation. This has led to mid-latitude and climate changes being attributed to AA, identified through the use of climate reanalysis and atmospheric simulations. However, other studies have shown only a weak link. This inconsistency may result from deficiencies in separating the effects of AA from those of natural variability or background warming.

In a new Nature Climate Change article, author Mirong Song, and MAPP-funded PI Aiguo Dai, use coupled climate model simulations with and without AA. It was found that cold-season precipitation, snowfall, and circulation changes over northern mid-latitudes come mostly from background warming. In addition, AA and sea-ice loss increase precipitation and snowfall above ~60° N and reduce meridional temperature gradients above ~45° N in the lower–mid troposphere. However, minimal impact on the mean climate is seen below ~60° N. These results suggest that the climatic impacts of AA are probably small outside the high latitudes, thus caution is needed in attributing mid-latitude changes to AA and sea-ice loss.

Read the paper here

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The Modeling, Analysis, Predictions, and Projections (MAPP) Program is a competitive research program in NOAA Research's Climate Program Office. MAPP's mission is to enhance the Nation's and NOAA's capability to understand, predict, and project variability and long-term changes in Earth's system and mitigate human and economic impacts. To achieve its mission, MAPP supports foundational research, transition of research to applications, and engagement across other parts of NOAA, among partner agencies, and with the external research community. MAPP plays a crucial role in enabling national preparedness for extreme events like drought and longer-term climate changes. For more information, please visit www.cpo.noaa.gov/MAPP.

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