doi:10.1007/s00376-015-5184-6

An S.-I., S.-H. Im, 2014: Blunt ocean dynamical thermostat in response of tropical eastern Pacific SST to global warming. Theor. Appl. Climatol., 118, 173- 183.

Bjerknes J., 1969: Atmospheric teleconnections from the equatorial Pacific. Mon. Wea. Rev., 97, 163- 172.

Cane, M. A., Coauthors , 1997: Twentieth-century Sea surface temperature trends. Science, 275, 957- 960.

Clement A. C., R. Seager, M. A. Cane, and S. E. Zebiak, 1996: An ocean dynamical thermostat. J. Climate, 9, 2190- 2196.

Collins M., 2005: El Niño- or La Niña-like climate change? Climate Dyn., 24, 89- 104.

DiNezio P. N., A. C. Clement, G. A. Vecchi, B. J. Soden, B. P. Kirtman, and S.-K. Lee, 2009: Climate response of the equatorial Pacific to global warming. J. Climate, 22, 4873- 4892.10.1175/2009JCLI2982.1

7218d148092b59c3bcaa726c1036d118

http%3A%2F%2Fwww.cabdirect.org%2Fabstracts%2F20093283579.html

http://www.cabdirect.org/abstracts/20093283579.htmlAbstract The climate response of the equatorial Pacific to increased greenhouse gases is investigated using numerical experiments from 11 climate models participating in the Intergovernmental Panel on Climate Change鈥檚 Fourth Assessment Report. Multimodel mean climate responses to CO 2 doubling are identified and related to changes in the heat budget of the surface layer. Weaker ocean surface currents driven by a slowing down of the Walker circulation reduce ocean dynamical cooling throughout the equatorial Pacific. The combined anomalous ocean dynamical plus radiative heating from CO 2 is balanced by different processes in the western and eastern basins: Cloud cover feedbacks and evaporation balance the heating over the warm pool, while increased cooling by ocean vertical heat transport balances the warming over the cold tongue. This increased cooling by vertical ocean heat transport arises from increased near-surface thermal stratification, despite a reduction in vertical velocity. The stratification response is found to be a permanent feature of the equilibrium climate potentially linked to both thermodynamical and dynamical changes within the equatorial Pacific. Briefly stated, ocean dynamical changes act to reduce (enhance) the net heating in the east (west). This explains why the models simulate enhanced equatorial warming, rather than El Ninoike warming, in response to a weaker Walker circulation. To conclude, the implications for detecting these signals in the modern observational record are discussed.

Du Y., S.-P. Xie, 2008: Role of atmospheric adjustments in the tropical Indian ocean warming during the 20th century in climate models. Geophys. Res. Lett., 35, L08712.10.1029/2008GL033631

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2008GL033631%2Ffull

refpaperuri:(f842c8fa4d30aff0d6c91beed4ef465f)

http://onlinelibrary.wiley.com/doi/10.1029/2008GL033631/fullThe tropical Indian Ocean has been warming steadily since 1950s, a trend simulated by a large ensemble of climate models. In models, changes in net surface heat flux are small and the warming is trapped in the top 125 m depth. Analysis of the model output suggests the following quasi-equilibrium adjustments among various surface heat flux components. The warming is triggered by the greenhouse gas-induced increase in downward longwave radiation, amplified by the water vapor feedback and atmospheric adjustments such as weakened winds that act to suppress turbulent heat flux from the ocean. The sea surface temperature dependency of evaporation is the major damping mechanism. The simulated changes in surface solar radiation vary considerably among models and are highly correlated with inter-model variability in SST trend, illustrating the need to reduce uncertainties in cloud simulation.

Held I. M., B. J. Soden, 2006: Robust responses of the hydrological cycle to global warming. J. Climate, 19, 5686- 5699.10.1175/JCLI3990.1

7ae5758e-a821-4cf9-9505-eb4e6bbf6dbd

cdbeb87fdb1d4a8e38d603c2100e3e38

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2006JCli...19.5686H

refpaperuri:(b47c2cf123cd1129f081eb2f0757a438)

http://adsabs.harvard.edu/abs/2006JCli...19.5686HAbstract Using the climate change experiments generated for the Fourth Assessment of the Intergovernmental Panel on Climate Change, this study examines some aspects of the changes in the hydrological cycle that are robust across the models. These responses include the decrease in convective mass fluxes, the increase in horizontal moisture transport, the associated enhancement of the pattern of evaporation minus precipitation and its temporal variance, and the decrease in the horizontal sensible heat transport in the extratropics. A surprising finding is that a robust decrease in extratropical sensible heat transport is found only in the equilibrium climate response, as estimated in slab ocean responses to the doubling of CO 2 , and not in transient climate change scenarios. All of these robust responses are consequences of the increase in lower-tropospheric water vapor.

Huang P., 2015: Seasonal changes in tropical SST and the surface energy budget under global warming projected by CMIP5 models. J. Climate, 28, 6503- 6515.10.1175/JCLI-D-15-0055.1

437da42c9601a1209e33b386f9931962

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2015JCli...28.6503H

http://adsabs.harvard.edu/abs/2015JCli...28.6503HABSTRACT The seasonal changes in tropical SST under global warming are investigated based on the RCP 8.5 and historical runs in 31 CMIP5 models. The tropical SST changes show three pronounced seasonal patterns, the peak locking to the equator throughout the year, the weaker equatorial changes and stronger hemispheric asymmetric changes (HAC) in boreal autumn. The magnitude of the seasonal patterns is comparable to the tropical-mean warming and the annual-mean patterns, implying great impacts on global climate changes. The peak locking to the equator is a result of the equatorial locking of the minimum damping of climatological latent heat flux and the ocean heat transport changes. Except the role of ocean heat transport suggested in previous studies, the weaker equatorial warming in boreal autumn is contributed by the stronger evaporation damping due to the stronger climatological evaporation and the increased surface wind speed. The seasonal variations of the HAC are driven by the variations of the damping effect of climatological evaporation. In boreal summer, the damping effect of climatological evaporation, greater in the Southern Hemisphere, promotes the development of the HAC. Consequently, the HAC peaks in boreal autumn when the damping effect of climatological evaporation transforms to a reverse meridional pattern, greater in the Northern Hemisphere. The wind-evaporation-SST feedback, as the key process of the annual-mean HAC, plays an amplifying role to the seasonal variations of the HAC in tropical SST.

Huang P., J. Ying, 2015: A multimodel ensemble pattern regression method to correct the tropical Pacific SST change patterns under global warming. J. Climate, 28, 4706- 4723.10.1175/JCLI-D-14-00833.1

655d708a9e3bd8376a25a7688b2c5612

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2015JCli...28.4706H

http://adsabs.harvard.edu/abs/2015JCli...28.4706HABSTRACT This study develops a new observational constraint method, called multi-model ensemble pattern regression (EPR), to correct the projections of regional climate change by conventional unweighted multi-model mean (MMM). The EPR method first extracts leading modes of historical bias using inter-model EOF analysis, then builds up the linear correlated modes between historical bias and change bias using multi-variant linear regression, and finally estimates the common change bias induced by common historical bias. Along with correcting common change bias, the EPR method implicitly removes the inter-model uncertainty in the change projection deriving from the inter-model diversity in background simulation. The EPR method is applied to correct the patterns of tropical Pacific SST changes using the historical and RCP 8.5 runs in 30 CMIP5 models and observed SSTs. The common bias patterns of the tropical Pacific SSTs in historical runs, including the excessive cold tongue, the southeastern warm bias and the narrower warm pool, are estimated to induce La Niña-like change biases. After the estimated common change biases are removed, the corrected SST changes display a pronounced El Niño-like pattern and have much greater zonal gradients. The bias correction decreases by around half of the inter-model uncertainties in the MMM SST projections. The patterns of corrected tropical precipitation and circulation change are dominated by the enhanced SST change patterns, displaying a pronounced warmer-get-wetter pattern and a decreased Walker circulation with decreased uncertainties.

Huang P., S.-P. Xie, K. M. Hu, G. Huang, and R. H. Huang, 2013: Patterns of the seasonal response of tropical rainfall to global warming. Nature Geoscience, 6, 357- 361.10.1038/ngeo1792

d950ba00e73e3f2fb50bedd3e7a7732c

http%3A%2F%2Fwww.nature.com%2Fngeo%2Fjournal%2Fv6%2Fn5%2Fabs%2Fngeo1792.html

http://www.nature.com/ngeo/journal/v6/n5/abs/ngeo1792.htmlTropical convection is an important factor in regional climate variability and change around the globe . The response of regional precipitation to global warming is spatially variable, and state-of-the-art model projections suffer large uncertainties in the geographic distribution of precipitation changes . Two views exist regarding tropical rainfall change: one predicts increased rainfall in presently rainy regions (wet-get-wetter) , and the other suggests increased rainfall where the rise in sea surface temperature exceeds the mean surface warming in the tropics (warmer-get-wetter). Here we analyse simulations with 18 models from the Coupled Model Intercomparison Project (CMIP5), and present a unifying view for seasonal rainfall change. We find that the pattern of ocean warming induces ascending atmospheric flow at the Equator and subsidence on the flanks, anchoring a band of annual mean rainfall increase near the Equator that reflects the warmer-get-wetter view. However, this climatological ascending motion marches back and forth across the Equator with the Sun, pumping moisture upwards from the boundary layer and causing seasonal rainfall anomalies to follow a wet-get-wetter pattern. The seasonal mean rainfall, which is the sum of the annual mean and seasonal anomalies, thus combines the wet-get-wetter and warmer-get-wetter trends. Given that precipitation climatology is well observed whereas the pattern of ocean surface warming is poorly constrained , our results suggest that projections of tropical seasonal mean rainfall are more reliable than the annual mean.

Huang P., I. -I. Lin, C. Chou, and R. H. Huang, 2015: Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming. Nature Communications, 6, 7188.10.1038/ncomms8188

25982028

e5bc17e8e8cea2e47a77b2bea6dea8bf

http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpubmed%2F25982028

http://www.ncbi.nlm.nih.gov/pubmed/25982028Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas.

Knutson T. R., S. Manabe, 1995: Time-mean response over the tropical Pacific to increased CO₂ in a coupled ocean-atmosphere model. J. Climate, 8, 2181- 2199.10.1175/1520-0442(1995)0082.0.CO;2

ae999425-6278-49a8-8939-64737ce7ee9d

24f9a5b95af4d85534bd380b23c62bb9

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F1995JCli....8.2181K

refpaperuri:(5ed8b29fc588e8ce45fb31d0f7d640ad)

http://adsabs.harvard.edu/abs/1995JCli....8.2181KABSTRACT The time-mean response over the tropical Pacific region to a quadrupling of COâ is investigated using a global coupled ocean-atmosphere general circulation model. Tropical Pacific sea surface temperatures (SSTs) rise by about 4Â掳-5Â掳C. The zonal SST gradient along the equator decreases by about 20%, although it takes about one century (with COâ increasing at 1% per year compounded) for this change to become clearly evident in the model. Over the central equatorial Pacific, the decreased SST gradient is accompanied by similar decreases in the easterly wind stress and westward ocean surface currents and by a local maximum in precipitation increase. Over the entire rising branch region of the Walker circulation, precipitation is enhanced by 15%, but the time-mean upward motion decreases slightly in intensity. The failure of the zonal overturning atmospheric circulation to intensify with quadrupling of COâ is surprising in light of the increased time-mean condensation heating over the {open_quotes}warm pool{close_quotes} region. Three aspects of the model response are important for interpreting this result. (1) The time-mean radiative cooling of the upper troposphere is enhanced, due to both the pronounced upper-tropospheric warming and to the large fractional increase of upper-tropospheric water vapor. (2) The dynamical cooling term, -ÏâÎ¸/â(mo), is enhanced due to increased time-mean static stability (-âÎ¸/â(mo)). This is an effect of moist convection, which keeps the lapse rate close to the moist adiabatic rate, thereby making -âÎ¸/â(mo) larger in a warmer climate. The enhanced radiative cooling and increased static stability allow for the enhanced time-mean heating by moist convection and condensation to be balanced without stronger time-mean upward motions. 37 refs., 13 figs., 3 tabs.

Knutson T. R., J. J. Sirutis, S. T. Garner, G. A. Vecchi, and I. M. Held, 2008: Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions. Nature Geoscience, 1, 359- 364.10.1038/ngeo229

794df166dd7f74725429e37a48a802ac

http%3A%2F%2Fwww.nature.com%2Fngeo%2Fjournal%2Fv1%2Fn6%2Fabs%2Fngeo202.html

http://www.nature.com/ngeo/journal/v1/n6/abs/ngeo202.htmlIncreasing sea surface temperatures in the tropical Atlantic Ocean and measures of Atlantic hurricane activity have been reported to be strongly correlated since at least 1950 (refs 1 , 2 , 3 , 4 , 5 ), raising concerns that future greenhouse-gas-induced warming 6 could lead to pronounced increases in hurricane activity. Models that explicitly simulate hurricanes are needed to study the influence of warming ocean temperatures on Atlantic hurricane activity, complementing empirical approaches. Our regional climate model of the Atlantic basin reproduces the observed rise in hurricane counts between 1980 and 2006, along with much of the interannual variability, when forced with observed sea surface temperatures and atmospheric conditions 7 . Here we assess, in our model system 7 , the changes in large-scale climate that are projected to occur by the end of the twenty-first century by an ensemble of global climate models 8 , and find that Atlantic hurricane and tropical storm frequencies are reduced. At the same time, near-storm rainfall rates increase substantially. Our results do not support the notion of large increasing trends in either tropical storm or hurricane frequency driven by increases in atmospheric greenhouse-gas concentrations.

Liu Z. Y., S. Vavrus, F. He, N. Wen, and Y. F. Zhong, 2005: Rethinking tropical ocean response to global warming: The enhanced equatorial warming. J. Climate, 18, 4684- 4700.9a2898ce-4e22-46ff-86e6-dc01eb152e20

c4c706e2b4272325cced38e091add9bc

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2005JCli...18.4684L

refpaperuri:(19fa944ec0d13cc3a217b8f8c76ce708)

/s?wd=paperuri%3A%2819fa944ec0d13cc3a217b8f8c76ce708%29&filter=sc_long_sign&tn=SE_xueshusource_2kduw22v&sc_vurl=http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2005JCli...18.4684L&ie=utf-8

Ma J., S.-P. Xie, and Y. Kosaka, 2012: Mechanisms for tropical tropospheric circulation change in response to global warming. J. Climate, 25, 2979- 2994.10.1175/JCLI-D-11-00048.1

10877cb0-bc8d-4bc1-a201-c50fc5c0eefc

871a4bb2df0dd6e674297e8fcfd797a9

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2012JCli...25.2979M

refpaperuri:(04ff7fbe40b31f823b6655353843790c)

http://adsabs.harvard.edu/abs/2012JCli...25.2979MAbstract The annual-mean tropospheric circulation change in global warming is studied by comparing the response of an atmospheric general circulation model (GCM) to a spatial-uniform sea surface temperature (SST) increase (SUSI) with the response of a coupled ocean鈥揳tmosphere GCM to increased greenhouse gas concentrations following the A1B scenario. In both simulations, tropospheric warming follows the moist adiabat in the tropics, and static stability increases globally in response to SST warming. A diagnostic framework is developed based on a linear baroclinic model (LBM) of the atmosphere. The mean advection of stratification change (MASC) by climatological vertical motion, often neglected in interannual variability, is an important thermodynamic term for global warming. Once MASC effect is included, LBM shows skills in reproducing GCM results by prescribing latent heating diagnosed from the GCMs. MASC acts to slow down the tropical circulation. This is most clear in the SUSI run where the Walker circulation slows down over the Pacific without any change in SST gradient. MASC is used to decelerate the Hadley circulation, but spatial patterns of SST warming play an important role. Specifically, the SST warming is greater in the Northern than Southern Hemisphere, an interhemispheric asymmetry that decelerates the Hadley cell north, but accelerates it south of the equator. The MASC and SST-pattern effects are on the same order of magnitude in our LBM simulations. The former is presumably comparable across GCMs, while SST warming patterns show variations among models in both shape and magnitude. Uncertainties in SST patterns account for intermodel variability in Hadley circulation response to global warming (especially on and south of the equator).

Ma J., S.-P. Xie, 2013: Regional patterns of Sea surface temperature change: A source of uncertainty in future projections of precipitation and atmospheric circulation. J. Climate, 26, 2482- 2501.10.1175/JCLI-D-12-00283.1

17656025

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574bdc05ab6ad6fd4faf913b18553de6

http%3A%2F%2Flink.springer.com%2F10.1186%2F2193-1801-3-652

refpaperuri:(49fa4d965f2d0d5268aae93344398e67)

http://d.wanfangdata.com.cn/Periodical_dxqy-e201302006.aspxPrecipitation change in response to global warming has profound impacts on environment for life but is highly uncertain. Effects of sea surface temperature (SST) warming on the response of rainfall and atmospheric overturning circulation are investigated using Coupled Model Intercomparison Project simulations. The SST warming is decomposed into a spatially uniform SST increase (SUSI) and deviations from it. The SST pattern effect is found to be important in explaining both the multimodel ensemble mean distribution and intermodel variability of rainfall change over tropical oceans. In the ensemble mean, the annual rainfall change follows a 'warmer-get-wetter' pattern, increasing where the SST warming exceeds the tropical mean, and vice versa. Two SST patterns stand out both in the ensemble mean and intermodel variability: an equatorial peak anchoring a local precipitation increase and a meridional dipole mode with increased rainfall and weakened trade winds over the warmer hemisphere. These two modes of intermodel variability in SST account for one-third of intermodel spread in rainfall projection. The SST patterns can explain up to four-fifths of the intermodel variability in intensity changes of overturning circulations. SUSI causes both the Hadley and Walker circulations to slow down, as articulated by previous studies. The weakening of the Walker circulation is robust across models as the SST pattern effect is weak. The Hadley circulation change, by contrast, is significantly affected by SST warming patterns. As a result, near and south of the equator, the Hadley circulation strength change is weak in the multimodel ensemble mean and subject to large intermodel variability due to the differences in SST warming patterns.

Ma J., J.-Y. Yu, 2014: Linking centennial surface warming patterns in the equatorial Pacific to the relative strengths of the Walker and Hadley circulations. J. Atmos. Sci., 71, 3454- 3464.10.1175/JAS-D-14-0028.1

e90199de7146559a5e294acadf701340

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2014JAtS...71.3454M

http://adsabs.harvard.edu/abs/2014JAtS...71.3454MAbstract This study analyzes representative concentration pathway 4.5 projections by 18 models from phase 5 of the Coupled Model Intercomparison Project to show that surface warming patterns in the equatorial Pacific during the twenty-first century (centennial warming) are influenced by the relative strengths of the Walker and Hadley circulations. The stronger the Hadley (Walker) circulation is, the greater the surface warming in the central Pacific (CP) [eastern Pacific (EP)]. The EP warming is associated with the Bjerknes feedback, while the CP warming is associated with the wind–evaporation–sea surface temperature feedback. This atmospheric circulation influence on the centennial warming is similar to that found for the EP and CP El Ni09o. This suggests a methodology to constrain the estimate of the projected surface warming patterns in the equatorial Pacific using recent El Ni09o activity. The constraint indicates that the “most likely” centennial warming patterns have a maximum in the EP and are 39% weaker than the warming projected by the 18-model mean. The most-likely projection also shows alternating stronger and weaker warming in the subtropical North Pacific, which is not predicted by the 18-model mean projection. Nevertheless, the two projections agree on the minimum warming in the southeastern subtropical Pacific.

Meehl G. A., W. M. Washington, 1996: El Niño-like climate change in a model with increased atmospheric CO₂ concentrations. Nature, 382, 56- 60.

Ramanathan V., W. Collins, 1991: Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 El Niño. Nature, 351, 27- 32.10.1038/351027a0

697556d3fa407493756b8570bc06b290

http%3A%2F%2Fwww.nature.com%2Fnature%2Fjournal%2Fv351%2Fn6321%2Fabs%2F351027a0.html

http://www.nature.com/nature/journal/v351/n6321/abs/351027a0.htmlPresents observations made during the 1987 El Nino that show that in the upper range of sea surface temperatures, the greenhouse effect increases with surface temperature at a rate which exceeds the rate at which radiation is being emitted from the surface. Highly reflective cirrus clouds are produced which act like a thermostat, shielding the ocean from solar radiation.

Seager R., R. Murtugudde, 1997: Ocean dynamics, thermocline adjustment, and regulation of tropical SST. J. Climate, 10, 521- 534.

Song, X. L, G. J. Zhang, 2014: Role of climate feedback in El Niño-like SST response to global warming. J. Climate, 27, 7301- 7318.10.1175/JCLI-D-14-00072.1

8fbdfd81-9645-46d8-bba9-fefcc1b56399

f26051340eedab06201c65a27e5c17b7

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2014JCli...27.7301S

refpaperuri:(074242e5a682cbceb58ef23fa404d54d)

http://adsabs.harvard.edu/abs/2014JCli...27.7301SAbstract Under global warming from the doubling of CO 2 , the equatorial Pacific experiences an El Ni09o–like warming, as simulated by most global climate models. A new climate feedback and response analysis method (CFRAM) is applied to 10 years of hourly output of the slab ocean model (SOM) version of the NCAR Community Climate System Model, version 3.0, (CCSM3-SOM) to determine the processes responsible for this warming. Unlike the traditional surface heat budget analysis, the CFRAM can explicitly quantify the contributions of each radiative climate feedback and of each physical and dynamical process of a GCM to temperature changes. The mean bias in the sum of partial SST changes due to each feedback derived with CFRAM in the tropical Pacific is negligible (0.5%) compared to the mean SST change from the CCSM3-SOM simulations, with a spatial pattern correlation of 0.97 between the two. The analysis shows that the factors contributing to the El Ni09o–like SST warming in the central Pacific are different from those in the eastern Pacific. In the central Pacific, the largest contributor to El Ni09o–like SST warming is dynamical advection, followed by PBL diffusion, water vapor feedback, and surface evaporation. In contrast, in the eastern Pacific the dominant contributor to El Ni09o–like SST warming is cloud feedback, with water vapor feedback further amplifying the warming.

Sun D.-Z., J. Fasullo, T. Zhang, and A. Roubicek, 2003: On the radiative and dynamical feedbacks over the equatorial Pacific cold tongue. J. Climate, 16, 2425- 2432.10.1175/2786.1

a7d399ec310f91ebcba15565cf9046b3

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2003JCli...16.2425S

http://adsabs.harvard.edu/abs/2003JCli...16.2425SAn analysis of the climatic feedbacks in the NCAR Community Climate Model, version 3 (CCM3) over the equatorial Pacific cold tongue is presented. Using interannual signals in the underlying SST, the radiative and dynamical feedbacks have been calculated using both observations and outputs from the NCAR CCM3. The results show that the positive feedback from the greenhouse effect of water vapor in the model largely agrees with that from observations. The dynamical feedback from the atmospheric transport in the model is also comparable to that from observations. However, the negative feedback from the solar forcing of clouds in the model is significantly weaker than the observed, while the positive feedback from the greenhouse effect of clouds is significantly larger. Consequently, the net atmospheric feedback in the CCM3 over the equatorial cold tongue region is strongly positive (5.1 W m[SUP-2]K[SUP-1]), while the net atmospheric feedback in the real atmosphere is strongly negative (26.4 W m[SUP-2]K[SUP-1]). A further analysis with the aid of the International Satellite Cloud Climatology Project (ISCCP) data suggests that cloud cover response to changes in the SST may be a significant error source for the cloud feedbacks. It is also noted that the surface heating over the cold tongue in CCM3 is considerably weaker than in observations. In light of results from a linear feedback system, as well as those from a more sophisticated coupled model, it is suggested that the discrepancy in the net atmospheric feedback may have contributed significantly to the cold bias in the equatorial Pacific in the NCAR Climate System Model (CSM).

Sun D.Z., Coauthors , 2006: Radiative and dynamical feedbacks over the equatorial cold tongue: Results from nine atmospheric GCMs. J. Climate, 19, 4059- 4074.a35767051ec00efbc1626455df1f87b5

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2006JCli...19.4059S

/s?wd=paperuri%3A%2866bb7eaac993a71472c4a0ac6903a45f%29&filter=sc_long_sign&tn=SE_xueshusource_2kduw22v&sc_vurl=http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2006JCli...19.4059S&ie=utf-8

Taylor K. E., R. J. Stouffer, and G. A. Meehl, 2012: An overview of CMIP5 and the experiment design. Bull. Amer. Meteor. Soc., 93, 485- 498.10.1175/BAMS-D-11-00094.1

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http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F235793806_An_Overview_of_CMIP5_and_the_Experiment_Design%3Fev%3Dauth_pub

refpaperuri:(102c64f576f0dc49ca552e6df691421b)

http://www.researchgate.net/publication/235793806_An_Overview_of_CMIP5_and_the_Experiment_Design?ev=auth_pubThe fifth phase of the Coupled Model Intercomparison Project (CMIP5) will produce a state-of-the- art multimodel dataset designed to advance our knowledge of climate variability and climate change. Researchers worldwide are analyzing the model output and will produce results likely to underlie the forthcoming Fifth Assessment Report by the Intergovernmental Panel on Climate Change. Unprecedented in scale and attracting interest from all major climate modeling groups, CMIP5 includes “long term” simulations of twentieth-century climate and projections for the twenty-first century and beyond. Conventional atmosphere–ocean global climate models and Earth system models of intermediate complexity are for the first time being joined by more recently developed Earth system models under an experiment design that allows both types of models to be compared to observations on an equal footing. Besides the longterm experiments, CMIP5 calls for an entirely new suite of “near term” simulations focusing on recent decades and the future to year 2035. These “decadal predictions” are initialized based on observations and will be used to explore the predictability of climate and to assess the forecast system's predictive skill. The CMIP5 experiment design also allows for participation of stand-alone atmospheric models and includes a variety of idealized experiments that will improve understanding of the range of model responses found in the more complex and realistic simulations. An exceptionally comprehensive set of model output is being collected and made freely available to researchers through an integrated but distributed data archive. For researchers unfamiliar with climate models, the limitations of the models and experiment design are described.

Vecchi G. A., B. J. Soden, 2007: Global warming and the weakening of the tropical circulation. J. Climate, 20, 4316- 4340.10.1175/JCLI4258.1

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http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2006AGUFMOS11A1467W

refpaperuri:(b30ccd0a9e8c71855c1ae5c8c7674dc2)

http://adsabs.harvard.edu/abs/2006AGUFMOS11A1467WAbstract This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a coordinated set of twenty-first-century climate model experiments performed for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The strength of the atmospheric overturning circulation decreases as the climate warms in all IPCC AR4 models, in a manner consistent with the thermodynamic scaling arguments of Held and Soden. The weakening occurs preferentially in the zonally asymmetric (i.e., Walker) rather than zonal-mean (i.e., Hadley) component of the tropical circulation and is shown to induce substantial changes to the thermal structure and circulation of the tropical oceans. Evidence suggests that the overall circulation weakens by decreasing the frequency of strong updrafts and increasing the frequency of weak updrafts, although the robustness of this behavior across all models cannot be confirmed because of the lack of data. As the climate warms, changes in both the atmospheric and ocean circulation over the tropical Pacific Ocean resemble “El Ni09o–like” conditions; however, the mechanisms are shown to be distinct from those of El Ni09o and are reproduced in both mixed layer and full ocean dynamics coupled climate models. The character of the Indian Ocean response to global warming resembles that of Indian Ocean dipole mode events. The consensus of model results presented here is also consistent with recently detected changes in sea level pressure since the mid–nineteenth century.

Xie S.-P., S. G. H. Philander, 1994: A coupled ocean-atmosphere model of relevance to the ITCZ in the eastern Pacific. Tellus A, 46, 340- 350.10.1034/j.1600-0870.1994.t01-1-00001.x

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1034%2Fj.1600-0870.1994.t01-1-00001.x%2Fcitedby

refpaperuri:(41fa295687dddc17dd448e78313360fc)

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0870.1994.t01-1-00001.x/citedbyABSTRACT The intertropical convergence zone (ITCZ) stays in the northern hemisphere over the Atlantic and eastern Pacific, even though the annual mean position of the sun is on the equator. To study some processes that contribute to this asymmetry about the equator, we use a two-dimensional model which neglects zonal variations and consists of an ocean model with a mixed layer coupled to a simple atmospheric model. In this coupled model, the atmosphere not only transports momentum into the ocean, but also directly affects sea surface temperature by means of wind stirring and surface latent heat flux. Under equatorially symmetric conditions, the model has, in addition to an equatorially symmetric solution, two asymmetric solutions with a single ITCZ that forms in only one hemisphere. Strong equatorial upwelling is essential for the asymmetry. Local oceanic turbulent processes involving vertical mixing and surface latent heat flux, which are dependent on wind speed, also contribute to the asymmetry.

Xie S.-P., C. Deser, G. A. Vecchi, J. Ma, H. Y. Teng, and A. T. Wittenberg, 2010: Global warming pattern formation: Sea surface temperature and rainfall. J. Climate, 23, 966- 986.10.1175/2009JCLI3329.1

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http%3A%2F%2Fwww.cabdirect.org%2Fabstracts%2F20103118162.html

refpaperuri:(b0ebeb07b4f54809d624dfe9936fb36c)

http://www.cabdirect.org/abstracts/20103118162.htmlAbstract Spatial variations in sea surface temperature (SST) and rainfall changes over the tropics are investigated based on ensemble simulations for the first half of the twenty-first century under the greenhouse gas (GHG) emission scenario A1B with coupled ocean鈥揳tmosphere general circulation models of the Geophysical Fluid Dynamics Laboratory (GFDL) and National Center for Atmospheric Research (NCAR). Despite a GHG increase that is nearly uniform in space, pronounced patterns emerge in both SST and precipitation. Regional differences in SST warming can be as large as the tropical-mean warming. Specifically, the tropical Pacific warming features a conspicuous maximum along the equator and a minimum in the southeast subtropics. The former is associated with westerly wind anomalies whereas the latter is linked to intensified southeast trade winds, suggestive of wind鈥揺vaporation鈥揝ST feedback. There is a tendency for a greater warming in the northern subtropics than in the southern subtropics in accordance with asymmetries in trade wind changes. Over the equatorial Indian Ocean, surface wind anomalies are easterly, the thermocline shoals, and the warming is reduced in the east, indicative of Bjerknes feedback. In the midlatitudes, ocean circulation changes generate narrow banded structures in SST warming. The warming is negatively correlated with wind speed change over the tropics and positively correlated with ocean heat transport change in the northern extratropics. A diagnostic method based on the ocean mixed layer heat budget is developed to investigate mechanisms for SST pattern formation. Tropical precipitation changes are positively correlated with spatial deviations of SST warming from the tropical mean. In particular, the equatorial maximum in SST warming over the Pacific anchors a band of pronounced rainfall increase. The gross moist instability follows closely relative SST change as equatorial wave adjustments flatten upper-tropospheric warming. The comparison with atmospheric simulations in response to a spatially uniform SST warming illustrates the importance of SST patterns for rainfall change, an effect overlooked in current discussion of precipitation response to global warming. Implications for the global and regional response of tropical cyclones are discussed.

Zhang L., T. Li, 2014: A simple analytical model for understanding the formation of Sea surface temperature patterns under global warming. J. Climate, 27, 8413- 8421.5db19371857e24b1a62404f67e768de1

http%3A%2F%2Fadsabs.harvard.edu%2Fabs%2F2014JCli...27.8413Z

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