Article
Meteorology & Atmospheric Sciences
Tyler Cox, Kyle C. Armour, Gerard H. Roe, Aaron Donohoe, Dargan M. W. Frierson
Summary: This study focuses on the controls of atmospheric heat transport, specifically radiation and dynamics. The research shows that rotation rate and radiative tendency influence the strength of the Hadley cell and the efficiency of heat transport by eddies, with these controls not always operating independently and sometimes reinforcing each other. The study also examines how different components of atmospheric heat transport vary with latitude and how they sum to produce a smoothly varying total heat transport with latitude.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Katrina L. Hui, Simona Bordoni
Summary: Recent studies show that the rapid onset of the monsoon can be explained by a shift in tropical circulation, from a regime controlled by eddy momentum fluxes to one controlled by energetic constraints. The position of the equatorward coastal boundary influences these transitions, with tropical continents facilitating the establishment of an overturning circulation conducive to a monsoon regime. Conversely, lack of land at tropical latitudes prevents rapid displacement of moist static energy into the subtropics, hindering the establishment of an angular momentum-conserving monsoon regime.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2021)
Article
Meteorology & Atmospheric Sciences
D. J. Webb, P. Spence, R. M. Holmes, M. H. England
Summary: The study shows that anomalous changes in Southern Ocean wind patterns can lead to variations in the North Atlantic overturning circulation, with a more significant response observed in scenarios where the winds intensify poleward. The primary mechanism linking these changes is the propagation of baroclinic waves, with differences in the sign of the waves leading to contrasting impacts on the Atlantic Meridional Overturning Circulation (AMOC).
JOURNAL OF CLIMATE
(2021)
Article
Oceanography
Michael A. Spall
Summary: This study aims to investigate how midlatitude winds drive the meridional overturning circulation (MOC) and found different responses of MOC under different forcing periods. Additionally, the importance of nonlinear effects and mesoscale eddies on MOC was demonstrated.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Meteorology & Atmospheric Sciences
Yen-Ting Hwang, Hung-Yi Tseng, Kuan-Chen Li, Sarah M. Kang, Yung-Jen Chen, John C. H. Chiang
Summary: This study investigates the transient responses of atmospheric energy and momentum fluxes to an extratropical thermal heating in a model coupled to an aquaplanet mixed layer ocean. Two stages are observed in the teleconnection: a decrease in the meridional temperature gradient in midlatitudes leads to weakening of the eddy momentum flux and a reduction of the Hadley cell, followed by the development of a deep tropical cross-equatorial cell. The response time scale differs between the two stages, with the latter stage dependent on mixed layer depth.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Yechul Shin, Sarah M. Kang, Ken Takahashi, Malte F. Stuecker, Yen-Ting Hwang, Doyeon Kim
Summary: The study found that high-frequency extratropical forcing does not affect tropical precipitation, while low-frequency extratropical forcing allows atmospheric transient eddies to diffuse moist static energy to perturb midlatitude sea surface temperatures, ultimately achieving further equatorward advection through the Hadley circulation.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Haijin Dai, Qiang Yao
Summary: Idealized numerical simulations reveal the response of atmospheric and oceanic circulations to Arctic warming at different timescales. Arctic warming leads to sea-ice melting and inhibits deep-water formation, weakening the Atlantic Meridional Overturning Circulation (AMOC). The strength and width of the Hadley cell (HC) are affected by the nearly uniform surface warming in mid-low latitudes and the temperature-wind-gyre-temperature cycle triggered by long-term response to high latitude warming. The HC response is also influenced by tropical warming, reduced surface albedo, and weakened AMOC.
ADVANCES IN ATMOSPHERIC SCIENCES
(2023)
Article
Meteorology & Atmospheric Sciences
Matthew T. Luongo, Shang-Ping Xie, Ian Eisenman
Summary: In this study, the researchers investigate the partitioning between buoyancy and momentum forcing in the ocean's response to changes in cross-equatorial ocean heat transport (OHT). They find that buoyancy-driven changes in the deep Atlantic meridional overturning circulation (AMOC) dominate in the Atlantic, while buoyancy-driven changes in the Indo-Pacific's shallow subtropical cells (STCs) are the primary driver of heat transport changes in the Indo-Pacific. The results suggest that understanding the ocean's total response to energy perturbations by partitioning into buoyancy and momentum forcing provides insight into how the ocean damps intertropical convergence zone (ITCZ) migrations.
JOURNAL OF CLIMATE
(2022)
Article
Oceanography
Michael J. Bell, Adam T. Blaker, Joel J-M Hirschi
Summary: Large-amplitude, high-frequency oscillations in the Pacific Ocean near the equator are found to be mainly wind-driven and can be well simulated using mathematical models. By studying different modes involved in these oscillations, it is also found that the best agreement in simulations is obtained by considering the effects of different driving forces.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Meteorology & Atmospheric Sciences
Weimin Jiang, Guillaume Gastineau, Francis Codran
Summary: The climate responses to fluctuations in the Atlantic meridional overturning circulation (AMOC) were investigated using sensitivity experiments. Modifications were made to the baroclinic component of the North Atlantic Ocean currents in an atmosphere-ocean general circulation model, which reproduced the typical AMOC multidecadal variability. Results showed that a strong AMOC led to widespread warming in the Northern Hemisphere and a northward shift of the intertropical convergence zone over the Atlantic Ocean. The driving mechanism for these climate responses was found to be an anomalous cross-equatorial Hadley circulation transporting energy and moisture.
JOURNAL OF CLIMATE
(2023)
Article
Multidisciplinary Sciences
Leon Chafik, N. Penny Holliday, Sheldon Bacon, Jonathan A. Baker, Damien Desbruyeres, Eleanor Frajka-Williams, Laura C. Jackson
Summary: The overturning circulation of the subpolar North Atlantic (SPNA) is crucial for Earth's climate variability and change. Based on observations, the recent warming in the eastern SPNA since 2016 is primarily caused by increased western boundary density at the intergyre boundary, which is likely a response to the strong increase in the North Atlantic Oscillation since the early 2010s. These positive density anomalies spread southward along the western boundary, enhancing the North Atlantic Current and meridional heat transport, leading to an increased influx of subtropical heat into the eastern SPNA.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Review
Meteorology & Atmospheric Sciences
Frank J. Pavia, C. Spencer Jones, Sophia K. Hines
Summary: This paper critically assesses the approaches used to determine the geometry of Atlantic circulation during the Last Glacial Maximum (LGM) and provides best practices for future research. The study highlights the complexity of interpreting geochemical proxies as water mass structure due to small-scale mixing processes in the ocean interior. It outlines promising paths for further ascertaining the LGM circulation structure.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
B. J. Hoskins, G. -Y. Yang
Summary: The global perspective presented in this paper emphasizes the importance of deep tropical convection in influencing the dynamics of the upper branch of the Hadley cell. The westward movement of filamentary outflows from tropical convection events and their interaction with the winter subtropical jet contribute to the flux of westerly momentum from the winter tropics to the summer hemisphere. The interaction between tropical and extratropical systems plays a significant role in the dynamics of the Hadley cell.
JOURNAL OF CLIMATE
(2023)
Article
Geosciences, Multidisciplinary
Qianjiang Xing, Andreas Klocker, David Munday, Joanne Whittaker
Summary: This study demonstrates the crucial role of turbulent processes in setting the strength of the global ocean's deep-reaching Meridional Overturning Circulation (MOC) and explains the dynamics behind the changes in the lower cell of the MOC associated with the geological evolution of Southern Ocean gateways. The opening of a gateway leads to the abrupt onset of a vigorous, deep-reaching MOC, which decreases with further deepening of the gateway.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Maria J. Molina, Aixue Hu, Gerald A. Meehl
Summary: Consequences of an AMOC slowdown or collapse could include changes to ENSO and the development of PMOC. However, our understanding of the influence of AMOC and PMOC on ENSO and global SSTs is limited. This study found that an AMOC shutdown leads to a decrease in tropical Pacific SSTs and an increase in ENSO amplitude, while active deep overturning circulations in both the Atlantic and Pacific basins reduce ENSO amplitude globally. The underlying mechanisms driving these changes differ depending on PMOC state.
JOURNAL OF CLIMATE
(2022)