Spatial variation of future trends in Atlantic upwelling cells from two CMIP6 models

Fuente: arXiv
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Main Authors: Flügel, Raquel, Herbette, Steven, Treguier, Anne-Marie, Waldman, Robin, Roberts, Malcolm
Format: Preprint
Published: 2025
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author Flügel, Raquel
Herbette, Steven
Treguier, Anne-Marie
Waldman, Robin
Roberts, Malcolm
author_facet Flügel, Raquel
Herbette, Steven
Treguier, Anne-Marie
Waldman, Robin
Roberts, Malcolm
contents Eastern Boundary Upwelling Systems (EBUS) are characterized by wind-triggered upwelling of deep waters along the coast. They are hotspots of biological productivity and diversity and therefore have a high economic, ecological and social importance. In the past, different methods using surface data have been used to estimate upwelling. Recently, the IPCC has suggested directly assessing vertical velocities as a promising method. We use this method to study the two Atlantic EBUS from CMIP6 models from the HadGEM3-GC3.1 and the CNRM6-CM6 family, for both the historical period and a high-emission future scenario with spatial resolutions in the ocean component ranging from 1°to 1/12°. The two major upwelling regions are divided in subregions depending on their seasonality. The vertical transport index shows similar values to a wind-derived Ekman index. Directly evaluating upwelling from transport processes further provides information about the depth of the upwelling, which has previously been identified as an important factor for nutrient availability. We show that depending on the subregion of the upwelling system, different cell structures can be seen in terms of depth and distance to the coast of maximum velocities. When looking at possible future changes, high interannual variability limits the significance of the trends but could indicate a poleward shift of the upwelling regions.A detailed comparison of the spatial structures and the distinction in subregions is important to explain contradictory trends in previous works.
format Preprint
id arxiv_https___arxiv_org_abs_2501_12920
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spatial variation of future trends in Atlantic upwelling cells from two CMIP6 models
Flügel, Raquel
Herbette, Steven
Treguier, Anne-Marie
Waldman, Robin
Roberts, Malcolm
Atmospheric and Oceanic Physics
Eastern Boundary Upwelling Systems (EBUS) are characterized by wind-triggered upwelling of deep waters along the coast. They are hotspots of biological productivity and diversity and therefore have a high economic, ecological and social importance. In the past, different methods using surface data have been used to estimate upwelling. Recently, the IPCC has suggested directly assessing vertical velocities as a promising method. We use this method to study the two Atlantic EBUS from CMIP6 models from the HadGEM3-GC3.1 and the CNRM6-CM6 family, for both the historical period and a high-emission future scenario with spatial resolutions in the ocean component ranging from 1°to 1/12°. The two major upwelling regions are divided in subregions depending on their seasonality. The vertical transport index shows similar values to a wind-derived Ekman index. Directly evaluating upwelling from transport processes further provides information about the depth of the upwelling, which has previously been identified as an important factor for nutrient availability. We show that depending on the subregion of the upwelling system, different cell structures can be seen in terms of depth and distance to the coast of maximum velocities. When looking at possible future changes, high interannual variability limits the significance of the trends but could indicate a poleward shift of the upwelling regions.A detailed comparison of the spatial structures and the distinction in subregions is important to explain contradictory trends in previous works.
title Spatial variation of future trends in Atlantic upwelling cells from two CMIP6 models
topic Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2501.12920