The role of blocking circulation and emerging open water feedbacks on Greenland cold-season air temperature variability over the last century

Ballinger, T.J., Hanna, E., Hall, R. , Carr, R., Brasher, S., Osterberg, E., Cappelen, J., Tedesco, M., Ding, Q. and Mernild, S. (2020) The role of blocking circulation and emerging open water feedbacks on Greenland cold-season air temperature variability over the last century. International Journal of Climatology . ISSN 0899-8418

Full content URL: https://doi.org/10.1002/joc.6879

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The role of blocking circulation and emerging open water feedbacks on Greenland cold-season air temperature variability over the last century
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Abstract

Substantial marine, terrestrial, and atmospheric changes have occurred over the Greenland region during the last century. For example, several efforts have documented record-levels of Greenland Ice Sheet (GrIS) summer melt extent and intensity during the 2000s and 2010s, but relatively little work has been carried out to assess regional climatic changes in other seasons. Here, we focus on the less studied cold-season (i.e., autumn and winter) climate, tracing the long-term (1873–2013) variability of Greenland’s air temperatures through analyses of coastal observations and model8 derived outlet glacier series and their linkages with North Atlantic sea ice, sea surface temperature (SST), and atmospheric circulation indices. Through a statistical framework, large amounts of west and south Greenland temperature variance (up to r2~50%) can be explained by the seasonally contemporaneous combination of the Greenland Blocking Index (GBI) and the North Atlantic Oscillation (NAO; hereafter GBI). Lagged and concomitant Baffin sea-ice concentration (SIC) and the Atlantic Multidecadal Oscillation (AMO) seasonal indices account for small amounts of air temperature residual variance (r2<~10%) relative to the GBI. The correlations between GBI and autumn and winter air temperatures are predominantly positive and statistically-significant through time, while Baffin SIC conditions emerge as a significant covariate from the mid-20th century through the conclusion of the study period. The inclusion of the cold-season Pacific Decadal Oscillation (PDO) in multivariate analyses bolsters the air temperature variance explained by the North Atlantic regional predictors, suggesting the remote, background climate state is important to long-term Greenland temperature variability. These findings imply that large-scale tropospheric circulation has a strong control on surface temperature over Greenland through dynamic and thermodynamic impacts and stress the importance of understanding the evolving two-way linkages between the North Atlantic marine and atmospheric environment in order to more accurately predict Greenland seasonal climate variability and change through the 21st century.

Keywords:air temperatures, Greenland, Greenland Blocking Index, sea ice
Subjects:F Physical Sciences > F860 Climatology
Divisions:College of Science > School of Geography
ID Code:42549
Deposited On:21 Oct 2020 09:32

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