Motivation
The North Atlantic sea surface temperatures have been at record highs since March 2023. The mechanisms behind such extreme conditions are not fully understood, and several hypotheses are still under debate. The warming began before the 2023 El Niño fully developed, suggesting a weak connection. Additionally, the observed warming in 2023 exceeds the expected increase in North Atlantic sea surface temperatures following an El Niño event.
However, 2023 also saw unusually low dust levels from the Sahara. Special atmospheric conditions led to weaker surface winds, reducing the transport of Saharan dust westward over the Atlantic Ocean. Typically, dust reflects sunlight, but the reduction allowed more sunlight to be absorbed by the tropical Atlantic Ocean, potentially carried northward by ocean currents. A decrease in surface winds is also associated with less vertical mixing of the ocean and less evaporative cooling at the sea surface, which may contribute to a significant rise in sea surface temperatures. Could the lack of Saharan dust be a key factor driving the extreme North Atlantic warming beyond previous extremes?
Hypothesis
The extreme warmth in the North Atlantic in 2023 was likely driven by unusually low levels of Saharan dust, allowing more solar energy to be absorbed by the Atlantic Ocean than usual.
Method
Conduct multiple simulations with the Norwegian Earth System Model (NorESM), both with and without reduced Saharan dust, under different wind conditions to investigate the impact. Compare the results to observations and reanalysis products.
This project will familiarize the student with one of the primary tools researchers use to study climate under various scenarios: a climate model. The work will also provide experience in handling and analyzing large datasets.
