Article
Geosciences, Multidisciplinary
Chengfei He, Amy C. Clement, Mark A. Cane, Lisa N. Murphy, Jeremy M. Klavans, Tyler M. Fenske
Summary: The subpolar North Atlantic has experienced a decrease in sea surface temperature over the past century, known as the warming hole. While it is commonly believed to be caused by the slowdown of the Atlantic meridional overturning circulation, this study shows that the atmosphere alone can account for a significant portion of the observed cooling trend. Increased local westerlies enhance heat loss from the ocean, leading to the cooling effect. Wind-driven ocean processes may also contribute to the cooling, but the ultimate driver remains in the atmosphere.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Yuki Kusakabe, Toshihiko Takemura
Summary: By reducing sulphate aerosols in air pollution, a phenomenon called the North Atlantic Warming Hole (NAWH) can form, similar to the formation due to increased CO2 concentrations. Sensitivity experiments were conducted by varying sulphur dioxide (SO2) emissions, finding that the spatial patterns of NAWH due to changes in SO2 emissions were similar to those due to changes in CO2 concentrations, but the magnitude of the shifts in ocean parameters due to changes in SO2 emissions was larger, even when changes in global mean temperature were comparable.
SCIENTIFIC REPORTS
(2023)
Article
Meteorology & Atmospheric Sciences
Emilie C. Iversen, Oivind Hodnebrog, Lise Seland Graff, Bjorn Egil Nygaard, Trond Iversen
Summary: Climate projections in the North Atlantic region suffer from uncertainties, especially in precipitation. This study focuses on the North Atlantic warming hole (NAWH) and investigates the projected winter precipitation decrease in the northeastern North Atlantic region using the CESM2 model. The results suggest that changes in stratiform precipitation are influenced by storm-track changes, while convective precipitation decreases due to reduced sea surface temperatures associated with the NAWH.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Geosciences, Multidisciplinary
Said Qasmi
Summary: A statistical method combining climate models and observations is used to confirm the anthropogenic role in the cooling of the North Atlantic warming hole. Aerosols increase sea surface temperature while greenhouse gases contribute to the cooling. However, uncertainties remain in quantifying the impact of each anthropogenic forcing.
EARTH SYSTEM DYNAMICS
(2023)
Article
Multidisciplinary Sciences
Robin van der Ploeg, Margot J. Cramwinckel, Ilja J. Kocken, Thomas J. Leutert, Steven M. Bohaty, Chris D. Fokkema, Pincelli M. Hull, A. Nele Meckler, Jack J. Middelburg, Inigo A. Muller, Donald E. Penman, Francien Peterse, Gert-Jan Reichart, Philip F. Sexton, Maximilian Vahlenkamp, David De Vleeschouwer, Paul A. Wilson, Martin Ziegler, Appy Sluijs
Summary: The Middle Eocene Climatic Optimum (MECO) experienced a transient warming of 3 degrees Celsius, leading to increased salinity in the North Atlantic subtropical gyre and potentially a poleward expansion of its northern boundary.
Article
Multidisciplinary Sciences
Ryan E. Truchelut, Philip J. Klotzbach, Erica M. Staehling, Kimberly M. Wood, Daniel J. Halperin, Carl J. Schreck, Eric S. Blake
Summary: In recent decades, the North Atlantic hurricane seasons have been starting earlier, which is linked to warmer spring sea surface temperatures. Pre-season and early-season tropical cyclones have had significant impacts on populated areas, particularly in terms of precipitation. This trend is associated with more favorable thermodynamic conditions for tropical cyclone formation.
NATURE COMMUNICATIONS
(2022)
Article
Environmental Sciences
Clare Ostle, Peter Landschuetzer, Martin Edwards, Martin Johnson, Sunke Schmidtko, Ute Schuster, Andrew J. Watson, Carol Robinson
Summary: The North Atlantic Ocean is the most significant marine sink for anthropogenic CO2 emissions, and the variability and trends of this sink are influenced by changes in phytoplankton abundance and community structure. Increases in phytoplankton biomass in the subpolar regions and decreases in the subtropics are synchronous with temperature changes and contribute to the uptake of atmospheric CO2 in the North Atlantic.
ENVIRONMENTAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
T. Fenske, A. Clement
Summary: This study reexamines the relationships between low frequency climate modes in the Northern Hemisphere ocean basins using observed sea surface temperatures and climate model simulations. Improved methods of separating external and internal variability, as well as detrending techniques, are employed. The findings suggest that any internal connections between these modes are indistinguishable from random noise and that external forcing affects each region in similar ways, potentially causing an indirect link between the basins.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Marie-Jose Messias, Herle Mercier
Summary: Understanding the history and redistribution of ocean excess heat uptake is crucial for assessing climate warming. This study reconstructs ocean heat content change in the 25 degrees N Atlantic hydrographic section and finds that the delayed response of the ocean below 700 m to sea surface temperature change contributes significantly to warming at this latitude. Recent research also shows an increasing net excess heat transport across 25 degrees N, indicating that excess heat redistribution is a key driver of North Atlantic heat gain.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Kristopher B. Karnauskas, Ulla K. Heede, Lei Zhang
Summary: The warming of the eastern Pacific strongly influences the future changes in Atlantic hurricanes, particularly the effect of El Nino. The changes include the formation regions of hurricanes and the intensity of the El Nino/La Nina signal.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Multidisciplinary Sciences
Jose C. Fernandez-Alvarez, Albenis Perez-Alarcon, Jorge Eiras-Barca, Stefan Rahimi, Raquel Nieto, Luis Gimeno
Summary: This study predicts that global warming and changes in atmospheric circulation will affect the hydrological cycle and the intensity and position of moisture sources. By the end of the century, moisture from the North Atlantic Ocean is expected to increase precipitation in eastern North America and the British Isles, while moisture from the Mediterranean Sea will decrease precipitation in eastern Europe.
NATURE COMMUNICATIONS
(2023)
Article
Geosciences, Multidisciplinary
Yi Liu, Ziguang Li, Xiaopei Lin, Jun-Chao Yang
Summary: The study suggests that under greenhouse warming, the connection between El Nino and the tropical North Atlantic will strengthen, leading to an increase in anomalous warming/cooling and related weather extremes in the future.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Annika Drews, Wenjuan Huo, Katja Matthes, Kunihiko Kodera, Tim Kruschke
Summary: This study analyzes the impact of the Sun on decadal surface climate using a chemistry-climate model. The results show that the detectability of the solar influence on climate depends on the magnitude of the solar cycle, and a strong solar cycle can affect the decadal component of the North Atlantic Oscillation.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
Yurong Hou, Nathaniel C. Johnson, Chueh-Hsin Chang, Weijun Sun, Kai Man, Yujie Miao, Xichen Li
Summary: In recent decades, cold winters and springs over mid-latitude North America have been occurring frequently, contrary to the anthropogenic global warming trend. This study investigates the teleconnection between tropical oceans and North America, revealing that an anomalous tropical Atlantic warming can trigger a cold spring over central-western mid-latitude North America. The mechanisms revealed in this study have important implications for the predictability of cold springs over North America and various sectors such as agriculture, power supply, and public health.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
S. Fiedler, D. Putrasahan
Summary: This study demonstrates how changes in the global distribution of anthropogenic aerosols influence the spatial patterns of North Atlantic sea-surface temperature. The North Atlantic sea-surface temperatures show different response patterns in different periods, largely influenced by anthropogenic aerosols.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Multidisciplinary Sciences
Ben Bronselaer, Laure Zanna
Article
Meteorology & Atmospheric Sciences
Arthur P. Guillaumin, Laure Zanna
Summary: The study presents a stochastic Deep Learning parameterization trained on CM2.6 data, predicting both the mean and standard deviation of subgrid momentum forcing to form a Gaussian distribution, demonstrating potential for stochastic subgrid parameterization. Offline tests show the parameterization generalizes well and improves flow statistics in global oceans and changing climate conditions.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Jinping Wang, John A. Church, Xuebin Zhang, Jonathan M. Gregory, Laure Zanna, Xianyao Chen
Summary: By combining new estimates of various factors, we find that the sea-level trends observed at 272 tide gauges distributed globally agree with the sum of contributions, indicating that the local sea-level budget is essentially closed. Sea-level changes are mainly influenced by ocean dynamics and glacial isostatic adjustment.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
Rei Chemke, Laure Zanna, Clara Orbe, Lori T. Sentman, Lorenzo M. Polvani
Summary: Climate models predict an intensification of the wintertime North Atlantic Ocean storm track by the end of the century. This study explores the role of ocean-atmosphere coupling in this intensification, focusing on the effects of thermodynamic and dynamic ocean coupling. Results show that dynamic coupling is the main driver of future TEKE strengthening, while changes in surface heat flux have a smaller impact. Additionally, ocean heat flux convergence increases meridional temperature gradient in the North Atlantic, leading to increased eddy growth rate and strengthening of TEKE. These findings highlight the importance of monitoring and studying changes in ocean heat transport for climate change adaptation strategies.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Emily Newsom, Laure Zanna, Samar Khatiwala
Summary: This study aims to better understand the geographic pattern of ocean warming caused by human-driven climate change. The research finds that ocean warming patterns are influenced by both the ocean's heat absorption and changes in ocean currents, which are interconnected processes. Changes in ocean currents reduce regional variations in the build-up of new heat absorbed from the atmosphere. This finding is significant for predicting regional ocean warming and its impacts.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Matthew P. Couldrey, Jonathan M. Gregory, Xiao Dong, Oluwayemi Garuba, Helmuth Haak, Aixue Hu, William J. Hurlin, Jiangbo Jin, Johann Jungclaus, Armin Koehl, Hailong Liu, Sayantani Ojha, Oleg A. Saenko, Abhishek Savita, Tatsuo Suzuki, Zipeng Yu, Laure Zanna
Summary: The effect of anthropogenic climate change in the ocean is challenging to project due to the different responses of atmosphere-ocean general circulation models (AOGCMs). This study focuses on the changes in the Atlantic Meridional Overturning Circulation (AMOC), ocean heat content (Delta OHC), and the spatial pattern of ocean dynamic sea level (Delta zeta). The results show that the weakening of AMOC is mainly caused by the North Atlantic heat flux perturbation, and further weakened by a positive coupled heat flux feedback. The AMOC decline has significant impacts on the warming of the South Atlantic-Southern Ocean interface.
Article
Meteorology & Atmospheric Sciences
Elizabeth Yankovsky, Laure Zanna, K. Shafer Smith
Summary: Understanding the impact of eddies on flow structure is essential for climate models. This study investigates the influence of eddies on vertical structure as a function of resolution and dynamical regime. It examines the distribution of potential and kinetic energy and finds that increasing resolution leads to higher kinetic energy and lower potential energy, with the dominant trend being an increased fraction of kinetic energy going into the barotropic mode as eddies are better resolved. The study also explores how the underlying dynamical regime affects energetic pathways.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Meteorology & Atmospheric Sciences
Andrew Ross, Ziwei Li, Pavel Perezhogin, Carlos Fernandez-Granda, Laure Zanna
Summary: Recently, there has been an increasing use of machine learning models in parameterizing computationally intensive subgrid-scale processes in ocean models. In this study, the online performance, generalization capabilities, and sensitivity to data set design choices of these models were systematically evaluated. The choice of filtering and coarse-graining operator was found to be critical, and should be guided by the specific application. Additionally, a novel equation-discovery approach combining linear regression and genetic programming with spatial derivatives was proposed to improve generalization and interpretability.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2023)
Article
Meteorology & Atmospheric Sciences
Aakash Sane, Brandon G. Reichl, Alistair Adcroft, Laure Zanna
Summary: In this study, we improved a parameterization of vertical mixing in the ocean surface boundary layer by enhancing its eddy diffusivity model using data-driven methods, specifically neural networks. The improved scheme outperforms its predecessor by reducing biases in the mixed-layer depth and upper ocean stratification, demonstrating the potential for data-driven physics-aware parameterizations to improve global climate models.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2023)
Article
Meteorology & Atmospheric Sciences
Cheng Zhang, Pavel Perezhogin, Cem Gultekin, Alistair Adcroft, Carlos Fernandez-Granda, Laure Zanna
Summary: This study addresses how to use machine learned parameterization in a general circulation model and evaluates its performance. The researchers found the parameterization to be stable but identified some limitations in its implementation, suggesting further refinement may be needed.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2023)
Proceedings Paper
Computer Science, Artificial Intelligence
Sheng Liu, Aakash Kaku, Weicheng Zhu, Matan Leibovich, Sreyas Mohan, Boyang Yu, Haoxiang Huang, Laure Zanna, Narges Razavian, Jonathan Niles-Weed, Carlos Fernandez-Granda
Summary: This work investigates probability estimation from high-dimensional data using deep neural networks. The study evaluates existing methods on synthetic and real-world data, and proposes a new method that outperforms existing approaches. The importance of reliable probability estimation in applications with inherent uncertainty is emphasized.
INTERNATIONAL CONFERENCE ON MACHINE LEARNING, VOL 162
(2022)
Review
Environmental Sciences
Lijing Cheng, Karina von Schuckmann, John P. Abraham, Kevin E. Trenberth, Michael E. Mann, Laure Zanna, Matthew H. England, Jan D. Zika, John T. Fasullo, Yongqiang Yu, Yuying Pan, Jiang Zhu, Emily R. News, Ben Bronselaer, Xiaopei Lin
Summary: This Review synthesizes estimates of past and future ocean heat content (OHC) changes using observations and models. The top 2,000 m of the global ocean has significantly warmed since the 1950s, with the rate of warming increasing over the decades. The observed warming is largest in the Atlantic Ocean and southern oceans, and the projected future warming will have extensive impacts on marine ecosystems and society.
NATURE REVIEWS EARTH & ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Gustavo M. Marques, Nora Loose, Elizabeth Yankovsky, Jacob M. Steinberg, Chiung-Yin Chang, Neeraja Bhamidipati, Alistair Adcroft, Baylor Fox-Kemper, Stephen M. Griffies, Robert W. Hallberg, Malte F. Jansen, Hemant Khatri, Laure Zanna
Summary: We describe an idealized primitive-equation model for studying mesoscale turbulence and use a hierarchy of grid resolutions to make eddy-resolving calculations more affordable. The model incorporates intermediate complexity, with idealized basin-scale geometry and non-uniform ocean depth, allowing for mesoscale eddy interactions with topography. The model is perfectly adiabatic and fills a gap between quasi-geostrophic models and idealized general circulation models. Results show that the model is approaching convergence in mean kinetic energy for the ocean mesoscale processes of interest and exhibits a wide range of dynamics due to resolving mesoscale turbulence.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2022)
Correction
Meteorology & Atmospheric Sciences
Michael P. Byrne, Laure Zanna
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Matthew P. Couldrey, Jonathan M. Gregory, Fabio Boeira Dias, Peter Dobrohotoff, Catia M. Domingues, Oluwayemi Garuba, Stephen M. Griffies, Helmuth Haak, Aixue Hu, Masayoshi Ishii, Johann Jungclaus, Armin Kohl, Simon J. Marsland, Sayantani Ojha, Oleg A. Saenko, Abhishek Savita, Andrew Shao, Detlef Stammer, Tatsuo Suzuki, Alexander Todd, Laure Zanna
Summary: Research shows that the differences in sea level changes between different AOGCMs are mainly caused by variations in ocean model formulation, rather than diversity in surface flux. Heat flux drives the global pattern of sea level change, while momentum and water flux changes cause localized features. North Atlantic heat uptake and transport adjustment are important factors affecting sea level changes.