IV. H OW DOES THE HIGH - LATITUDE THERMAL FORCING IN ONE
4.4 S UMMARY AND D ISCUSSION
Figure 4.10. Schematic that depicts how the high-latitude warming in one hemisphere affects the other hemisphere. The red bulb indicates polar warming in the forced hemisphere whose effect spreads equatorward through the lower troposphere. The ascending branch of the Hadley cell is shifted toward a warmer Northern Hemisphere, accompanied by a stronger southern Hadley cell and an increase in angular momentum transport toward the southern subtropics. Consequently, the subtropical jet is accelerated, pulling the eddy-driven jet equatorward. The resulting anomalous eddy momentum divergence in the southern extratropics induces anomalous upper-tropospheric northerlies, leading to anomalous descent over the high latitudes, thereby adiabatically warming the polar region of the unforced hemisphere. The polar surface warming then propagates into the tropics, modulating the tropical response to a direct forcing.
The near-surface warming signal at the south pole re-propagates toward the equator, forming a mini-global warming pattern. With the aid of a partially prescribed SST experiment, we confirm that the tropical SST response of the unforced hemisphere originates from the polar region of the unforced hemisphere. Note that one of the major signatures of a mini- global warming pattern, the tropical upper-tropospheric warming, emerges when the Hadley circulation shifts, far in advance to the tropical surface warming of the unforced hemisphere.
The schematic diagram summarizes the proposed mechanism (Figure 4.10). In our experiments, the polar SST response of the unforced hemisphere is as large as 31% of that of the forced hemisphere. The internal variability of the polar surface temperature tends to be large, but the pole-to-pole connection is significant at a 95% confidence level in our model.
Since it takes 5.1 years for the surface thermal forcing of one pole to perturb the surface temperature of the other pole, it is likely to be difficult to detect the pole-to-pole signal in observations. Nevertheless, our study reveals that the two polar regions can be tightly connected on decadal timescales via atmospheric dynamics.
A pole-to-pole linkage mediated by atmospheric dynamics alone turns out to be synchronous temperature variations in the two polar regions. Although dynamic ocean feedbacks are absent in our experiment setup, this synchronous behavior is consistent with the climate response to projected Arctic or Antarctic sea-ice loss in a fully coupled model (Deser et al. 2015; England et al. 2020a). This is contrary to the typical bipolar seesaw discussed in the paleoclimate context. We speculate that marine biogeochemistry, not considered in the aforementioned studies, may shift the synchronous to the asynchronous behavior. For example, a weakened SH mid-latitude jet in response to a NH warming (Fig.
4.3c) may reduce wind-driven upwelling over the Southern Ocean. A consequent decrease in oceanic CO2 vented up to the atmosphere would lead to the southern high-latitude and global
cooling (Anderson et al. 2009). As different climate components that are operative on various timescales work differently, future studies are warranted that carefully examine the pole-to- pole signal by systematically adding complexities to a model. A primary goal of this paper, however, is to highlight the existence of a pole-to-pole linkage solely shaped by zonal-mean atmospheric dynamics.
Acknowledgements
We thank Mark England and an anonymous reviewer for their constructive comments. Y. S.
was funded Global Ph.D. fellowship (2017H1A2A1044044) by the National Research Foundation of Korea (NRF). The dataset supporting the conclusions of this article is available in the PANGEA repository (https://doi.pangaea.de/10.1594/PANGAEA.936786).
Chapter 5 Conclusion
Analyzing a series of idealized experiments and conducting theoretical models, this thesis attempt to outline the mechanism by which extratropical variability propagates from its source, perturbing tropical general circulation and the opposite hemisphere. After reviewing progress in our understanding and motivating further challenges in Chapter 1, we investigate temporal sensitivity (Chapter 2) and sequential mechanisms (Chapter 3) of the extratropics- to-tropics teleconnection, further expanding it to pole-to-pole teleconnection (Chapter 4).
Chapter 2 uses sinusoidally time-varying surface fluxes imposed in an extratropical slab ocean to investigate the sensitivity of tropical climate response to timescales of extratropical fluctuations. The ITCZ migration is profoundly sensitive to the time scale of extratropical forcing. In our model configuration (i.e., aquaplanet and 50-m slab ocean model), the extratropical fluctuations with a 3-yr and longer period induce a meridional ITCZ shift with a clear quasi-sinusoidal temporal evolution, while ITCZ responses are highly muted to a 1-yr period (or shorter) extratropical fluctuations. The unrecognized threshold behavior of tropical climate indicates that the ability of extratropical fluctuations in perturbing the tropical precipitation pattern relies on the time scale. Hence, the mixed layer depth, one of the important time scale determinants in our planet, rules the response time scale of extratropics-to-tropics teleconnection, consistent with a previous study (e.g., Woelfle et al. 2015). The sensitivity is mainly caused by the importance of SST propagation into the tropics, largely consistent with expectations from prior literature; for example, TOA energetic imbalance leads to a fast but very minor tropical response with prescribed SST boundary
(Voigt et al. 2017). Considering the time tendency of the atmospheric energy budget, we utilize an energetic framework: extratropical energy perturbations can alter the tropical precipitation only when accompanied by an equatorward propagation of the SST response before completely damped. Chapter 3 describes sequential mechanisms of extratropics-to- tropics teleconnection. Adapting advantages of periodically time-varying experiments, objectively identifying the sequence of the atmospheric pathway and governing dynamics.
Atmospheric eddies firstly react to energetic imbalance to reduce thermal gradient by transporting surplus energy toward the tropics. We conduct a diffusive one-dimensional energy balance model to support the dynamics. The sensitivity of tropical climate to the extratropical forcing is caused by these eddies that require sufficient time to adjust nearby SSTs. A transition takes place from the eddy-driven to mean circulation-dominated. The impacts of eddies must be weakened as it goes toward the tropics. Hence, as the surplus energy is transported into the boundary of Hadley circulation, the return flow of the cell advects the anomalous heat from subtropics to the deep tropics. We devise a simple thermodynamical-advective model representing coupled atmospheric and oceanic mixed layers to describe an essential role of lower tropospheric MSE advection.
Chapter 2 and 3 together provide an integrated view of extratropics-to-tropics teleconnection. As the SST propagation is a prerequisite of tropical response, low-frequency variabilities in the extratropics (e.g., AMV) that is sufficient to propagate are more appropriate to perturb tropical climate. A recent study suggests 4 years as a time lag between forced AMV and precipitation, whereas a few decades (24 years) as that of natural AMV (Moreno-Chamarro et al., 2019), which is not easily accepting that a distinct time scale is required to perturb tropical climate from same AMV. Based on our results, the atmospheric
extratropical-forced AMV touches tropics via lower tropospheric propagation. The internally driven AMV has a smaller amplitude (about a fourth); thus, it is highly possible that the AMV signal is damped in extratropics before propagating toward the tropics via atmospheric response. Hence, it requires a decadal time scale that should be associated with oceanic dynamics, AMOC. In terms of discrepancies in observing evidence and paleoclimate (or modeling) evidence, Paleoclimate proxies are low-frequency variabilities, tropical climate responses appearing coherently. However, not only the time scale of extratropics-to-tropics teleconnection that is far longer than usual (tropics-to-extratropics teleconnection) but also requiring low-frequency extratropical perturbation would hamper identification of extratropics-to-tropics teleconnection. Also, non-dispersive propagation inside of the Hadley cell boundaries may imply potential predictability of tropics from high-frequency off- equatorial agents (e.g., aerosol), which should be examined in a realistic model and observation.
The remaining chapter focus on expanding extratropics-originated impacts to global climate, pole-to-pole atmospheric teleconnection. Employing periodically time-varying forcing induces responses easily distinguished from internal variability, helping to identify new teleconnection patterns and mechanisms. As the thermal response in one high-latitude perturbs the tropical climate, the following consequent atmospheric response in terms of momentum balance to the Hadley cell shift is shown in the mid-latitude jet stream, secondary circulation, and thermal response in the opposite high-latitude. Although it is an idealized zonal-mean connection between the two poles, several factors are suggesting further analysis in observation and model. One is that the well-known response pattern of polar warming, tropical upper tropospheric and near-surface polar warming, occurs together with the pole- to-pole teleconnection. The other is that the pole-to-pole teleconnection also modifies the
tropical temperature gradient and hence ITCZ migration. The pole-to-pole teleconnection suggests an integrated consideration of the Arctic and Antarctic amplification in future climate.
Bibliography
Adam, O., Schneider, T., Brient, F., & Bischoff, T. (2016). Relation of the double-ITCZ bias to the atmospheric energy budget in climate models. Geophysical Research Letters, 43(14), 7670–7677.
https://doi.org/10.1002/2016GL069465
Alexander, M. A., Bladé, I., Newman, M., Lanzante, J. R., Lau, N.-C., & Scott, J. D. (2002). The Atmospheric Bridge: The Influence of ENSO Teleconnections on Air–Sea Interaction over the Global Oceans. Journal of Climate, 15(16), 2205–2231. https://doi.org/10.1175/1520-0442(2002)015<2205:TABTIO>2.0.CO;2
Amaya, D. J. (2019). The Pacific Meridional Mode and ENSO: A Review. Current Climate Change Reports, 5(4), 296–307. https://doi.org/10.1007/s40641-019-00142-x
Anderson, R. F., Ali, S., Bradtmiller, L. I., Nielsen, S. H. H., Fleisher, M. Q., Anderson, B. E., & Burckle, L. H.
(2009). Wind-Driven Upwelling in the Southern Ocean and the Deglacial Rise in Atmospheric CO2. Science, 323(5920), 1443–1448. https://doi.org/10.1126/science.1167441
Arakawa, A., & Schubert, W. H. (1974). Interaction of a Cumulus Cloud Ensemble with the Large-Scale Environment, Part I. Journal of the Atmospheric Sciences, 31(3), 674–701. https://doi.org/10.1175/1520- 0469(1974)031<0674:IOACCE>2.0.CO;2
Barbante, C., Barnola, J.-M., Becagli, S., Beer, J., Bigler, M., Boutron, C., Blunier, T., Castellano, E., Cattani, O., Chappellaz, J., Dahl-Jensen, D., Debret, M., Delmonte, B., Dick, D., Falourd, S., Faria, S., Federer, U., Fischer, H., Freitag, J., … EPICA Community Members. (2006). One-to-one coupling of glacial climate variability in Greenland and Antarctica. Nature, 444(7116), 195–198. https://doi.org/10.1038/nature05301 Biasutti, M., & Voigt, A. (2020). Seasonal and CO2-Induced Shifts of the ITCZ: Testing Energetic Controls in Idealized Simulations with Comprehensive Models. Journal of Climate, 33(7), 2853–2870.
https://doi.org/10.1175/JCLI-D-19-0602.1
Bischoff, T., & Schneider, T. (2014). Energetic Constraints on the Position of the Intertropical Convergence Zone. Journal of Climate, 27(13), 4937–4951. https://doi.org/10.1175/JCLI-D-13-00650.1
Bischoff, T., Schneider, T., & Meckler, A. N. (2017). A Conceptual Model for the Response of Tropical Rainfall to Orbital Variations. Journal of Climate, 30(20), 8375–8391. https://doi.org/10.1175/JCLI-D-16-0691.1 Bjerknes, J. (1969). ATMOSPHERIC TELECONNECTIONS FROM THE EQUATORIAL PACIFIC. Monthly Weather Review, 97(3), 163–172. https://doi.org/10.1175/1520-0493(1969)097<0163:ATFTEP>2.3.CO;2 Blunier, T., & Brook, E. J. (2001). Timing of Millennial-Scale Climate Change in Antarctica and Greenland During the Last Glacial Period. Science, 291(5501), 109–112. https://doi.org/10.1126/science.291.5501.109 Brayshaw, D. J., Hoskins, B., & Blackburn, M. (2008). The Storm-Track Response to Idealized SST Perturbations in an Aquaplanet GCM. Journal of the Atmospheric Sciences, 65(9), 2842–2860.
https://doi.org/10.1175/2008JAS2657.1
Broccoli, A. J., Dahl, K. A., & Stouffer, R. J. (2006). Response of the ITCZ to Northern Hemisphere cooling.
Geophysical Research Letters, 33(1). https://doi.org/10.1029/2005GL024546
Budyko, M. I. (1969). The effect of solar radiation variations on the climate of the Earth. Tellus, 21(5), 611–
619. https://doi.org/10.1111/j.2153-3490.1969.tb00466.x
Buizert, C., Adrian, B., Ahn, J., Albert, M., Alley, R. B., Baggenstos, D., Bauska, T. K., Bay, R. C., Bencivengo, B. B., Bentley, C. R., Brook, E. J., Chellman, N. J., Clow, G. D., Cole-Dai, J., Conway, H., Cravens, E., Cuffey,
K. M., Dunbar, N. W., Edwards, J. S., … WAIS Divide Project Members. (2015). Precise interpolar phasing of abrupt climate change during the last ice age. Nature, 520(7549), 661–665. https://doi.org/10.1038/nature14401 Cabré, A., Marinov, I., & Gnanadesikan, A. (2017). Global Atmospheric Teleconnections and Multidecadal Climate Oscillations Driven by Southern Ocean Convection. Journal of Climate, 30(20), 8107–8126.
https://doi.org/10.1175/JCLI-D-16-0741.1
Ceppi, P., Hwang, Y.-T., Liu, X., Frierson, D. M. W., & Hartmann, D. L. (2013). The relationship between the ITCZ and the Southern Hemispheric eddy-driven jet. Journal of Geophysical Research: Atmospheres, 118(11), 5136–5146. https://doi.org/10.1002/jgrd.50461
Chiang, J. C. H., & Bitz, C. M. (2005). Influence of high latitude ice cover on the marine Intertropical Convergence Zone. Climate Dynamics, 25(5), 477–496. https://doi.org/10.1007/s00382-005-0040-5
Chiang, J. C. H., & Friedman, A. R. (2012). Extratropical Cooling, Interhemispheric Thermal Gradients, and Tropical Climate Change. Annual Review of Earth and Planetary Sciences, 40(1), 383–412.
https://doi.org/10.1146/annurev-earth-042711-105545
Chylek, P., Folland, C. K., Lesins, G., & Dubey, M. K. (2010). Twentieth century bipolar seesaw of the Arctic and Antarctic surface air temperatures. Geophysical Research Letters, 37(8).
https://doi.org/10.1029/2010GL042793
Clark, S. K., Ming, Y., Held, I. M., & Phillipps, P. J. (2018). The Role of the Water Vapor Feedback in the ITCZ Response to Hemispherically Asymmetric Forcings. Journal of Climate, 31(9), 3659–3678.
https://doi.org/10.1175/JCLI-D-17-0723.1
Cvijanovic, I., & Chiang, J. C. H. (2013). Global energy budget changes to high latitude North Atlantic cooling and the tropical ITCZ response. Climate Dynamics, 40(5), 1435–1452. https://doi.org/10.1007/s00382-012- 1482-1
de Boyer Montégut, C., Madec, G., Fischer, A. S., Lazar, A., & Iudicone, D. (2004). Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology. Journal of Geophysical Research:
Oceans, 109(C12). https://doi.org/10.1029/2004JC002378
Delworth, T. L., Zeng, F., Zhang, L., Zhang, R., Vecchi, G. A., & Yang, X. (2017). The Central Role of Ocean Dynamics in Connecting the North Atlantic Oscillation to the Extratropical Component of the Atlantic Multidecadal Oscillation. Journal of Climate, 30(10), 3789–3805. https://doi.org/10.1175/JCLI-D-16-0358.1 Denton, G. H., Anderson, R. F., Toggweiler, J. R., Edwards, R. L., Schaefer, J. M., & Putnam, A. E. (2010). The Last Glacial Termination. Science, 328(5986), 1652–1656. https://doi.org/10.1126/science.1184119
Deser, C., Phillips, A. S., Simpson, I. R., Rosenbloom, N., Coleman, D., Lehner, F., Pendergrass, A. G., DiNezio, P., & Stevenson, S. (2020). Isolating the Evolving Contributions of Anthropogenic Aerosols and Greenhouse Gases: A New CESM1 Large Ensemble Community Resource. Journal of Climate, 33(18), 7835–7858.
https://doi.org/10.1175/JCLI-D-20-0123.1
Deser, C., Tomas, R. A., & Sun, L. (2015). The Role of Ocean–Atmosphere Coupling in the Zonal-Mean Atmospheric Response to Arctic Sea Ice Loss. Journal of Climate, 28(6), 2168–2186.
https://doi.org/10.1175/JCLI-D-14-00325.1
Ding, Q., Wallace, J. M., Battisti, D. S., Steig, E. J., Gallant, A. J. E., Kim, H.-J., & Geng, L. (2014). Tropical forcing of the recent rapid Arctic warming in northeastern Canada and Greenland. Nature, 509(7499), 209–212.
https://doi.org/10.1038/nature13260
Donohoe, A., Marshall, J., Ferreira, D., Armour, K., & McGee, D. (2014). The Interannual Variability of
Donohoe, A., Marshall, J., Ferreira, D., & Mcgee, D. (2013). The Relationship between ITCZ Location and Cross-Equatorial Atmospheric Heat Transport: From the Seasonal Cycle to the Last Glacial Maximum. Journal of Climate, 26(11), 3597–3618. https://doi.org/10.1175/JCLI-D-12-00467.1
Donohoe, A., & Voigt, A. (2017). Why Future Shifts in Tropical Precipitation Will Likely Be Small. In Climate Extremes (pp. 115–137). American Geophysical Union (AGU). https://doi.org/10.1002/9781119068020.ch8 England, M. R. (2021). Are Multi-Decadal Fluctuations in Arctic and Antarctic Surface Temperatures a Forced Response to Anthropogenic Emissions or Part of Internal Climate Variability? Geophysical Research Letters, 48(6), e2020GL090631. https://doi.org/10.1029/2020GL090631
England, M. R., Polvani, L. M., & Sun, L. (2020). Robust Arctic warming caused by projected Antarctic sea ice loss. Environmental Research Letters, 15(10), 104005. https://doi.org/10.1088/1748-9326/abaada
England, M. R., Polvani, L. M., Sun, L., & Deser, C. (2020). Tropical climate responses to projected Arctic and Antarctic sea-ice loss. Nature Geoscience, 13(4), 275–281. https://doi.org/10.1038/s41561-020-0546-9 Feldl, N., & Bordoni, S. (2016). Characterizing the Hadley Circulation Response through Regional Climate Feedbacks. Journal of Climate, 29(2), 613–622. https://doi.org/10.1175/JCLI-D-15-0424.1
Frierson, D. M. W., & Hwang, Y.-T. (2012). Extratropical Influence on ITCZ Shifts in Slab Ocean Simulations of Global Warming. Journal of Climate, 25(2), 720–733. https://doi.org/10.1175/JCLI-D-11-00116.1
Frierson, D. M. W., Hwang, Y.-T., Fučkar, N. S., Seager, R., Kang, S. M., Donohoe, A., Maroon, E. A., Liu, X.,
& Battisti, D. S. (2013). Contribution of ocean overturning circulation to tropical rainfall peak in the Northern Hemisphere. Nature Geoscience, 6(11), 940–944. https://doi.org/10.1038/ngeo1987
Green, B., & Marshall, J. (2017). Coupling of Trade Winds with Ocean Circulation Damps ITCZ Shifts. Journal of Climate, 30(12), 4395–4411. https://doi.org/10.1175/JCLI-D-16-0818.1
Green, B., Marshall, J., & Campin, J.-M. (2019). The ‘sticky’ ITCZ: Ocean-moderated ITCZ shifts. Climate Dynamics, 53(1), 1–19. https://doi.org/10.1007/s00382-019-04623-5
Green, B., Marshall, J., & Donohoe, A. (2017). Twentieth century correlations between extratropical SST variability and ITCZ shifts. Geophysical Research Letters, 44(17), 9039–9047.
https://doi.org/10.1002/2017GL075044
Haine, T. W. N., & Martin, T. (2017). The Arctic-Subarctic sea ice system is entering a seasonal regime:
Implications for future Arctic amplification. Scientific Reports, 7(1), 4618. https://doi.org/10.1038/s41598-017- 04573-0
Haug, G. H., Günther, D., Peterson, L. C., Sigman, D. M., Hughen, K. A., & Aeschlimann, B. (2003). Climate and the Collapse of Maya Civilization. Science. https://doi.org/10.1126/science.1080444
Haug, G. H., Hughen, K. A., Sigman, D. M., Peterson, L. C., & Röhl, U. (2001). Southward Migration of the Intertropical Convergence Zone Through the Holocene. Science, 293(5533), 1304–1308.
https://doi.org/10.1126/science.1059725
Hawcroft, M., Haywood, J. M., Collins, M., Jones, A., Jones, A. C., & Stephens, G. (2017). Southern Ocean albedo, inter-hemispheric energy transports and the double ITCZ: Global impacts of biases in a coupled model.
Climate Dynamics, 48(7), 2279–2295. https://doi.org/10.1007/s00382-016-3205-5
Held, I. M., & Hou, A. Y. (1980). Nonlinear Axially Symmetric Circulations in a Nearly Inviscid Atmosphere.
Journal of the Atmospheric Sciences, 37(3), 515–533. https://doi.org/10.1175/1520- 0469(1980)037<0515:NASCIA>2.0.CO;2
Hill, S. A. (2019). Theories for Past and Future Monsoon Rainfall Changes. Current Climate Change Reports, 5(3), 160–171. https://doi.org/10.1007/s40641-019-00137-8
Horel, J. D., & Wallace, J. M. (1981). Planetary-Scale Atmospheric Phenomena Associated with the Southern Oscillation. Monthly Weather Review, 109(4), 813–829. https://doi.org/10.1175/1520- 0493(1981)109<0813:PSAPAW>2.0.CO;2
Hoskins, B. J., & Ambrizzi, T. (1993). Rossby Wave Propagation on a Realistic Longitudinally Varying Flow.
Journal of the Atmospheric Sciences, 50(12), 1661–1671. https://doi.org/10.1175/1520- 0469(1993)050<1661:RWPOAR>2.0.CO;2
Hoskins, B. J., & Karoly, D. J. (1981). The Steady Linear Response of a Spherical Atmosphere to Thermal and Orographic Forcing. Journal of the Atmospheric Sciences, 38(6), 1179–1196. https://doi.org/10.1175/1520- 0469(1981)038<1179:TSLROA>2.0.CO;2
Hwang, Y.-T., & Frierson, D. M. W. (2010). Increasing atmospheric poleward energy transport with global warming. Geophysical Research Letters, 37(24). https://doi.org/10.1029/2010GL045440
Hwang, Y.-T., Tseng, H.-Y., Li, K.-C., Kang, S. M., Chen, Y.-J., & Chiang, J. C. H. (2021). Relative Roles of Energy and Momentum Fluxes in the Tropical Response to Extratropical Thermal Forcing. Journal of Climate, 34(10), 3771–3786. https://doi.org/10.1175/JCLI-D-20-0151.1
Jennerjahn, T. C., Ittekkot, V., Arz, H. W., Behling, H., Pätzold, J., & Wefer, G. (2004). Asynchronous Terrestrial and Marine Signals of Climate Change During Heinrich Events. Science, 306(5705), 2236–2239.
https://doi.org/10.1126/science.1102490
Kang, S. M. (2020). Extratropical Influence on the Tropical Rainfall Distribution. Current Climate Change Reports, 6(1), 24–36. https://doi.org/10.1007/s40641-020-00154-y
Kang, S. M., Frierson, D. M. W., & Held, I. M. (2009). The Tropical Response to Extratropical Thermal Forcing in an Idealized GCM: The Importance of Radiative Feedbacks and Convective Parameterization. Journal of the Atmospheric Sciences, 66(9), 2812–2827. https://doi.org/10.1175/2009JAS2924.1
Kang, S. M., Hawcroft, M., Xiang, B., Hwang, Y.-T., Cazes, G., Codron, F., Crueger, T., Deser, C., Hodnebrog, Ø., Kim, H., Kim, J., Kosaka, Y., Losada, T., Mechoso, C. R., Myhre, G., Seland, Ø., Stevens, B., Watanabe, M., & Yu, S. (2019). Extratropical–Tropical Interaction Model Intercomparison Project (Etin-Mip): Protocol and Initial Results. Bulletin of the American Meteorological Society, 100(12), 2589–2606.
https://doi.org/10.1175/BAMS-D-18-0301.1
Kang, S. M., Held, I. M., Frierson, D. M. W., & Zhao, M. (2008). The Response of the ITCZ to Extratropical Thermal Forcing: Idealized Slab-Ocean Experiments with a GCM. Journal of Climate, 21(14), 3521–3532.
https://doi.org/10.1175/2007JCLI2146.1
Kang, S. M., Held, I. M., & Xie, S.-P. (2014). Contrasting the tropical responses to zonally asymmetric extratropical and tropical thermal forcing. Climate Dynamics, 42(7–8), 2033–2043.
https://doi.org/10.1007/s00382-013-1863-0
Kang, S. M., Kim, B.-M., Frierson, D. M. W., Jeong, S.-J., Seo, J., & Chae, Y. (2015). Seasonal Dependence of the Effect of Arctic Greening on Tropical Precipitation. Journal of Climate, 28(15), 6086–6095.
https://doi.org/10.1175/JCLI-D-15-0079.1
Kang, S. M., Seager, R., Frierson, D. M. W., & Liu, X. (2015). Croll revisited: Why is the northern hemisphere warmer than the southern hemisphere? Climate Dynamics, 44(5), 1457–1472. https://doi.org/10.1007/s00382- 014-2147-z
Kang, S. M., Shin, Y., & Codron, F. (2018). The partitioning of poleward energy transport response between the atmosphere and Ekman flux to prescribed surface forcing in a simplified GCM. Geoscience Letters, 5(1), 22. https://doi.org/10.1186/s40562-018-0124-9
Kang, S. M., Shin, Y., & Xie, S.-P. (2018). Extratropical forcing and tropical rainfall distribution: Energetics framework and ocean Ekman advection. Npj Climate and Atmospheric Science, 1(1), 1–10.
https://doi.org/10.1038/s41612-017-0004-6
Kang, S. M., Xie, S.-P., Shin, Y., Kim, H., Hwang, Y.-T., Stuecker, M. F., Xiang, B., & Hawcroft, M. (2020).
Walker circulation response to extratropical radiative forcing. Science Advances, 6(47), eabd3021.
https://doi.org/10.1126/sciadv.abd3021
Kay, J. E., Wall, C., Yettella, V., Medeiros, B., Hannay, C., Caldwell, P., & Bitz, C. (2016). Global Climate Impacts of Fixing the Southern Ocean Shortwave Radiation Bias in the Community Earth System Model (CESM). Journal of Climate, 29(12), 4617–4636. https://doi.org/10.1175/JCLI-D-15-0358.1
Kennett, J. P., & Ingram, B. L. (1995). A 20,000-year record of ocean circulation and climate change from the Santa Barbara basin. Nature, 377(6549), 510–514. https://doi.org/10.1038/377510a0
Kim, D., Kang, S. M., Shin, Y., & Feldl, N. (2018). Sensitivity of Polar Amplification to Varying Insolation Conditions. Journal of Climate, 31(12), 4933–4947. https://doi.org/10.1175/JCLI-D-17-0627.1
Kim, H., Kang, S. M., Takahashi, K., Donohoe, A., & Pendergrass, A. G. (2021). Mechanisms of tropical precipitation biases in climate models. Climate Dynamics, 56(1), 17–27. https://doi.org/10.1007/s00382-020- 05325-z
Klein, S. A., & Hall, A. (2015). Emergent Constraints for Cloud Feedbacks. Current Climate Change Reports, 1(4), 276–287. https://doi.org/10.1007/s40641-015-0027-1
Koutavas, A., & Lynch-Stieglitz, J. (2004). Variability of the Marine ITCZ over the Eastern Pacific during the Past 30,000 Years. In H. F. Diaz & R. S. Bradley (Eds.), The Hadley Circulation: Present, Past and Future (pp.
347–369). Springer Netherlands. https://doi.org/10.1007/978-1-4020-2944-8_13
Kraus, E. B. (1977). Subtropical Droughts and Cross-Equatorial Energy Transports. Monthly Weather Review, 105(8), 1009–1018. https://doi.org/10.1175/1520-0493(1977)105<1009:SDACEE>2.0.CO;2
Kug, J.-S., Oh, J.-H., An, S.-I., Yeh, S.-W., Min, S.-K., Son, S.-W., Kam, J., Ham, Y.-G., & Shin, J. (2021).
Hysteresis of the intertropical convergence zone to CO2 forcing. Nature Climate Change, 1–7.
https://doi.org/10.1038/s41558-021-01211-6
Laguë, M. M., & Swann, A. L. S. (2016). Progressive Midlatitude Afforestation: Impacts on Clouds, Global Energy Transport, and Precipitation. Journal of Climate, 29(15), 5561–5573. https://doi.org/10.1175/JCLI-D- 15-0748.1
Lea, D. W., Pak, D. K., Peterson, L. C., & Hughen, K. A. (2003). Synchroneity of Tropical and High-Latitude Atlantic Temperatures over the Last Glacial Termination. Science, 301(5638), 1361–1364.
https://doi.org/10.1126/science.1088470
Lee, S., & Kim, H. (2003). The Dynamical Relationship between Subtropical and Eddy-Driven Jets. Journal of the Atmospheric Sciences, 60(12), 1490–1503. https://doi.org/10.1175/1520- 0469(2003)060<1490:TDRBSA>2.0.CO;2
Lee, S.-Y., Chiang, J. C. H., Matsumoto, K., & Tokos, K. S. (2011). Southern Ocean wind response to North Atlantic cooling and the rise in atmospheric CO2: Modeling perspective and paleoceanographic implications.
Paleoceanography, 26(1). https://doi.org/10.1029/2010PA002004