The contributions of dynamical and diabatic processes preceding and accompanying major Greenland ice-melt events
Extratropical cyclones and/or short-wave disturbances can reinforce Greenland blocking through upper-level flow amplification and can increase poleward heat and moisture transport into the Arctic. Increased poleward heat and moisture transport into the Arctic may enhance Greenland ice melt during th...
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| Format: | Text |
| Language: | English |
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Scholars Archive
2021
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| Online Access: | https://scholarsarchive.library.albany.edu/legacy-etd/2680 https://scholarsarchive.library.albany.edu/context/legacy-etd/article/3679/viewcontent/Feldman_3yS4j5eRaYR6GHZ5EX3EXx.pdf |
| Summary: | Extratropical cyclones and/or short-wave disturbances can reinforce Greenland blocking through upper-level flow amplification and can increase poleward heat and moisture transport into the Arctic. Increased poleward heat and moisture transport into the Arctic may enhance Greenland ice melt during the spring, summer, and fall months. The need to better understand the underlying dynamical and diabatic processes that may contribute to Greenland ice melt motivates this thesis. The purpose of this thesis is to investigate: 1) the role of advective warming due to poleward heat and moisture transport into the Arctic in facilitating Greenland ice melt, 2) the role of adiabatic warming due to synoptic-scale descent associated with Greenland blocking in facilitating ice melt, and 3) the role of diabatic warming due to condensation and latent heating over Greenland in facilitating ice melt. Self-organizing maps (SOMs) are utilized to construct a synoptic climatology of Greenland ice-melt events during the April–October 1979–2019 time period. The SOMs identify three main types of synoptic-scale flow patterns during Greenland ice-melt events: 1) a blocking pattern over Greenland, 2) a positively tilted trough upstream of Greenland, and 3) a high-amplitude negatively tilted trough upstream of Greenland. During late July–early August 2019, 60% (i.e., ~984,000 km 2) of the Greenland ice sheet experienced melting, which is the largest ice melt event over Greenland since at least 2012. Ice melt over Greenland was associated with a blocking anticyclone over Scandinavia that subsequently shifted westward toward Greenland and permitted anomalously warm air of Saharan origin to reach Greenland. Upper-level flow amplification from eastern North America to western Europe resulted in ridge amplification over northwest Africa, which occurred in conjunction with the formation of an atmospheric river (AR) over the North Atlantic Ocean that was associated with a large poleward-directed moisture transport. Anomalously warm air of ... |
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