Editorial Type:
Article
Article Type:
Research Article

Understanding the Anthropogenically Forced Change of Equatorial Pacific Trade Winds in Coupled Climate Models

Baoqiang Xiang NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, and University Corporation for Atmospheric Research, Boulder, Colorado, and International Pacific Research Center, University of Hawai‘i at Mānoa, Honolulu, Hawaii

Search for other papers by Baoqiang Xiang in
Current site
Google Scholar
PubMed Close
,
Bin Wang International Pacific Research Center, and Department of Meteorology, University of Hawai‘i at Mānoa, Honolulu, Hawaii, and Earth System Modeling Center/NIAMS, Nanjing University of Information Science and Technology, Nanjing, China

Search for other papers by Bin Wang in
Current site
Google Scholar
PubMed Close
,
Juan Li International Pacific Research Center, University of Hawai‘i at Mānoa, Honolulu, Hawaii

Search for other papers by Juan Li in
Current site
Google Scholar
PubMed Close
,
Ming Zhao NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, and University Corporation for Atmospheric Research, Boulder, Colorado

Search for other papers by Ming Zhao in
Current site
Google Scholar
PubMed Close
, and
June-Yi Lee Institute of Environmental Studies, Pusan National University, Busan, South Korea

Search for other papers by June-Yi Lee in
Current site
Google Scholar
PubMed Close
Print Publication:
15 Nov 2014
DOI:
https://doi.org/10.1175/JCLI-D-14-00115.1
Page(s):
8510–8526
Restricted access

Abstract

Understanding the change of equatorial Pacific trade winds is pivotal for understanding the global mean temperature change and the El Niño–Southern Oscillation (ENSO) property change. The weakening of the Walker circulation due to anthropogenic greenhouse gas (GHG) forcing was suggested as one of the most robust phenomena in current climate models by examining zonal sea level pressure gradient over the tropical Pacific. This study explores another component of the Walker circulation change focusing on equatorial Pacific trade wind change. Model sensitivity experiments demonstrate that the direct/fast response due to GHG forcing is to increase the trade winds, especially over the equatorial central-western Pacific (ECWP) (5°S–5°N, 140°E–150°W), while the indirect/slow response associated with sea surface temperature (SST) warming weakens the trade winds.

Further, analysis of the results from 19 models in phase 5 of the Coupled Model Intercomparison Project (CMIP5) and the Parallel Ocean Program (POP)–Ocean Atmosphere Sea Ice Soil (OASIS)–ECHAM model (POEM) shows that the projected weakening of the trades is robust only in the equatorial eastern Pacific (EEP) ( 5°S–5°N, 150°–80°W), but highly uncertain over the ECWP with 9 out of 19 CMIP5 models producing intensified trades. The prominent and robust weakening of EEP trades is suggested to be mainly driven by a top-down mechanism: the mean vertical advection of more upper-tropospheric warming downward to generate a cyclonic circulation anomaly in the southeast tropical Pacific. In the ECWP, the large intermodel spread is primarily linked to model diversity in simulating the relative warming of the equatorial Pacific versus the tropical mean sea surface temperature. The possible root causes of the uncertainty for the trade wind change are also discussed.

School of Ocean and Earth Science and Technology Contribution Number 9186, International Pacific Research Center Contribution Number 1071, and Earth System Modeling Center Publication Number 010.

Corresponding author address: Baoqiang Xiang, NOAA/Geophysical Fluid Dynamics Laboratory, 201 Forrestal Rd., Princeton, NJ 08540. E-mail: baoqiang.xiang@noaa.gov

Abstract

Understanding the change of equatorial Pacific trade winds is pivotal for understanding the global mean temperature change and the El Niño–Southern Oscillation (ENSO) property change. The weakening of the Walker circulation due to anthropogenic greenhouse gas (GHG) forcing was suggested as one of the most robust phenomena in current climate models by examining zonal sea level pressure gradient over the tropical Pacific. This study explores another component of the Walker circulation change focusing on equatorial Pacific trade wind change. Model sensitivity experiments demonstrate that the direct/fast response due to GHG forcing is to increase the trade winds, especially over the equatorial central-western Pacific (ECWP) (5°S–5°N, 140°E–150°W), while the indirect/slow response associated with sea surface temperature (SST) warming weakens the trade winds.

Further, analysis of the results from 19 models in phase 5 of the Coupled Model Intercomparison Project (CMIP5) and the Parallel Ocean Program (POP)–Ocean Atmosphere Sea Ice Soil (OASIS)–ECHAM model (POEM) shows that the projected weakening of the trades is robust only in the equatorial eastern Pacific (EEP) ( 5°S–5°N, 150°–80°W), but highly uncertain over the ECWP with 9 out of 19 CMIP5 models producing intensified trades. The prominent and robust weakening of EEP trades is suggested to be mainly driven by a top-down mechanism: the mean vertical advection of more upper-tropospheric warming downward to generate a cyclonic circulation anomaly in the southeast tropical Pacific. In the ECWP, the large intermodel spread is primarily linked to model diversity in simulating the relative warming of the equatorial Pacific versus the tropical mean sea surface temperature. The possible root causes of the uncertainty for the trade wind change are also discussed.

School of Ocean and Earth Science and Technology Contribution Number 9186, International Pacific Research Center Contribution Number 1071, and Earth System Modeling Center Publication Number 010.

Corresponding author address: Baoqiang Xiang, NOAA/Geophysical Fluid Dynamics Laboratory, 201 Forrestal Rd., Princeton, NJ 08540. E-mail: baoqiang.xiang@noaa.gov
Save
Cover Journal of Climate
Journal of Climate

  • Bala, G., K. Caldeira, and R. Nemani, 2010: Fast versus slow response in climate change: Implications for the global hydrological cycle. Climate Dyn., 35, 423–434, doi:10.1007/s00382-009-0583-y.

    • Search Google Scholar
    • Export Citation

  • Cane, M. A., A. C. Clement, A. Kaplan, Y. Kushnir, D. Pozdnyakov, R. Seager, S. E. Zebiak, and R. Murtugudde, 1997: Twentieth century sea surface temperature trends. Science, 275, 957–960, doi:10.1126/science.275.5302.957.

    • Search Google Scholar
    • Export Citation

  • Christensen, J. H., and Coauthors, 2014: Climate phenomena and their relevance for future regional climate change. Climate Change 2013: The Physical Science Basis, T. F. Stocker et al., Eds., Cambridge University Press, 1217–1308.

    • Search Google Scholar
    • Export Citation

  • Clarke, A. J., and A. Lebedev, 1996: Long-term change in the equatorial Pacific trade winds. J. Climate, 9, 1020–1029, doi:10.1175/1520-0442(1996)009<1020:LTCITE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Clement, A. C., R. Seager, M. A. Cane, and S. E. Zebiak, 1996: An ocean dynamical thermostat. J. Climate, 9, 2190–2196, doi:10.1175/1520-0442(1996)009<2190:AODT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Dee, D. P., and Coauthors, 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553–597, doi:10.1002/qj.828.

    • Search Google Scholar
    • Export Citation

  • Deser, C., A. S. Phillips, and M. A. Alexander, 2010: Twentieth century tropical sea surface temperature trends revisited. Geophys. Res. Lett., 37, L10701, doi:10.1029/2010GL043321.

    • Search Google Scholar
    • Export Citation

  • DiNezio, P. N., G. A. Vecchi, and A. C. Clement, 2013: Detectability of change in the Walker circulation in response to global warming. J. Climate, 26, 4038–4048, doi:10.1175/JCLI-D-12-00531.1.

    • Search Google Scholar
    • Export Citation

  • Dong, B., and R. Lu, 2013: Interdecadal enhancement of the Walker circulation over the tropical Pacific in the late 1990s. Adv. Atmos. Sci., 30, 247–262, doi:10.1007/s00376-012-2069-9.

    • Search Google Scholar
    • Export Citation

  • Fu, Q., S. Manabe, and C. M. Johanson, 2011: On the warming in the tropical upper troposphere: Models versus observations. Geophys. Res. Lett., 38, L15704, doi:10.1029/2011GL048101.

    • Search Google Scholar
    • Export Citation

  • Held, I. M., and B. J. Soden, 2006: Robust responses of the hydrological cycle to global warming. J. Climate, 19, 5686–5699, doi:10.1175/JCLI3990.1.

    • Search Google Scholar
    • Export Citation

  • Held, I. M., and M. Zhao, 2011: The response of tropical cyclone statistics to an increase in CO2 with fixed sea surface temperature. J. Climate, 24, 5353–5364, doi:10.1175/JCLI-D-11-00050.1.

    • Search Google Scholar
    • Export Citation

  • Huang, X., and Coauthors, 2013: A radiative–convective equilibrium perspective of weakening of the tropical Walker circulation in response to global warming. J. Climate, 26, 1643–1653, doi:10.1175/JCLI-D-12-00288.1.

    • Search Google Scholar
    • Export Citation

  • Kanamitsu, M., W. Ebisuzaki, J. Woollen, S. K. Yang, J. J. Hnilo, M. Fiorino, and G. L. Potter, 2002: NCEP–DOE AMIP-II Reanalysis (R-2). Bull. Amer. Meteor. Soc., 83, 1631–1643, doi:10.1175/BAMS-83-11-1631.

    • Search Google Scholar
    • Export Citation

  • Knutson, T. R., and S. Manabe, 1995: Time-mean response over the tropical Pacific to increased CO2 in a coupled ocean–atmosphere model. J. Climate, 8, 2181–2199, doi:10.1175/1520-0442(1995)008<2181:TMROTT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Kosaka, Y., and S.-P. Xie, 2013: Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature, 501, 403–407, doi:10.1038/nature12534.

    • Search Google Scholar
    • Export Citation

  • Lee, J.-Y., and B. Wang, 2014: Future change of global monsoon in the CMIP5. Climate Dyn., 42, 101–119, doi:10.1007/s00382-012-1564-0.

    • Search Google Scholar
    • Export Citation

  • Lee, J.-Y., B. Wang, K.-H. Seo, J.-S. Kug, Y.-S. Choi, Y. Kosaka, and K.-J. Ha, 2014: Future change of Northern Hemisphere summer tropical–extratropical teleconnection in CMIP5 models. J. Climate, 27, 3643–3664, doi:10.1175/JCLI-D-13-00261.1.

    • Search Google Scholar
    • Export Citation

  • L’Heureux, M. L., S. Lee, and B. Lyon, 2013: Recent multidecadal strengthening of the Walker circulation across the tropical Pacific. Nat. Climate Change, 3, 571–576, doi:10.1038/nclimate1840.

    • Search Google Scholar
    • Export Citation

  • Li, W., and Coauthors, 2013: Intensification of the Southern Hemisphere summertime subtropical anticyclones in a warming climate. Geophys. Res. Lett., 40, 5959–5964, doi:10.1002/2013GL058124.

    • Search Google Scholar
    • Export Citation

  • Lin, J.-L., 2007: The double-ITCZ problem in IPCC AR4 coupled GCMs: Ocean–atmosphere feedback analysis. J. Climate, 20, 4497–4525, doi:10.1175/JCLI4272.1.

    • Search Google Scholar
    • Export Citation

  • Liu, Z., S. Vavrus, F. He, N. Wen, and Y. Zhong, 2005: Rethinking tropical ocean response to global warming: The enhanced equatorial warming. J. Climate, 18, 4684–4700, doi:10.1175/JCLI3579.1.

    • Search Google Scholar
    • Export Citation

  • Lu, J., and B. Zhao, 2012: The role of oceanic feedback in the climate response to doubling CO2. J. Climate, 25, 7544–7563, doi:10.1175/JCLI-D-11-00712.1.

    • Search Google Scholar
    • Export Citation

  • Ma, J., and 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, doi:10.1175/JCLI-D-12-00283.1.

    • Search Google Scholar
    • Export Citation

  • 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, doi:10.1175/JCLI-D-11-00048.1.

    • Search Google Scholar
    • Export Citation

  • Meng, Q., M. Latif, W. Park, N. S. Keenlyside, V. A. Semenov, and T. Martin, 2012: Twentieth century Walker circulation change: Data analysis and model experiments. Climate Dyn., 38, 1757–1773, doi:10.1007/s00382-011-1047-8.

    • Search Google Scholar
    • Export Citation

  • Muller, C. J., and P. A. O’Gorman, 2011: An energetic perspective on the regional response of precipitation to climate change. Nat. Climate Change, 1, 266–271, doi:10.1038/nclimate1169.

    • Search Google Scholar
    • Export Citation

  • Power, S. B., and G. Kociuba, 2011: What caused the observed twentieth-century weakening of the Walker circulation? J. Climate, 24, 6501–6514, doi:10.1175/2011JCLI4101.1.

    • Search Google Scholar
    • Export Citation

  • Roeckner, E., and Coauthors, 1996: The atmospheric general circulation model ECHAM-4: Model description and simulation of present-day climate. MPI Rep. 218, 90 pp. [Available online at http://www.mpimet.mpg.de/fileadmin/publikationen/Reports/MPI-Report_218.pdf.]

  • Sandeep, S., F. Stordal, P. D. Sardeshmukh, and G. P. Compo, 2014: Pacific Walker circulation variability in coupled and uncoupled climate models. Climate Dyn., 43, 103–117, doi:10.1007/s00382-014-2135-3.

    • Search Google Scholar
    • Export Citation

  • Solomon, A., and M. Newman, 2012: Reconciling disparate twentieth-century Indo-Pacific ocean temperature trends in the instrumental record. Nat. Climate Change, 2, 691–699, doi:10.1038/nclimate1591.

    • Search Google Scholar
    • Export Citation

  • Sugi, M., and J. Yoshimura, 2004: A mechanism of tropical precipitation change due to CO2 increase. J. Climate, 17, 238–243, doi:10.1175/1520-0442(2004)017<0238:AMOTPC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • 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, doi:10.1175/BAMS-D-11-00094.1.

    • Search Google Scholar
    • Export Citation

  • Tokinaga, H., S.-P. Xie, C. Deser, Y. Kosaka, and Y. M. Okumura, 2012a: Slowdown of the Walker circulation driven by tropical Indo-Pacific warming. Nature, 491, 439–443, doi:10.1038/nature11576.

    • Search Google Scholar
    • Export Citation

  • Tokinaga, H., S.-P. Xie, A. Timmermann, S. McGregor, T. Ogata, H. Kubota, and Y. M. Okumura, 2012b: Regional patterns of tropical Indo-Pacific climate change: Evidence of the Walker circulation weakening. J. Climate, 25, 1689–1710, doi:10.1175/JCLI-D-11-00263.1.

    • Search Google Scholar
    • Export Citation

  • Vecchi, G. A., and B. J. Soden, 2007: Global warming and the weakening of the tropical circulation. J. Climate, 20, 4316–4340, doi:10.1175/JCLI4258.1.

    • Search Google Scholar
    • Export Citation

  • Vecchi, G. A., B. J. Soden, A. T. Wittenberg, I. M. Held, A. Leetmaa, and M. J. Harrison, 2006: Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing. Nature, 441, 73–76, doi:10.1038/nature04744.

    • Search Google Scholar
    • Export Citation

  • Vecchi, G. A., A. C. Clement, and B. J. Soden, 2008: Examining the tropical Pacific’s response to global warming. Eos, Trans. Amer. Geophys. Union, 89, 81–83, doi:10.1029/2008EO090002.

    • Search Google Scholar
    • Export Citation

  • Xiang, B., and B. Wang, 2013: Mechanisms for the advanced Asian summer monsoon onset since the mid-to-late 1990s. J. Climate, 26, 1993–2009, doi:10.1175/JCLI-D-12-00445.1.

    • Search Google Scholar
    • Export Citation

  • Xiang, B., B. Wang, Q. Ding, F.-F. Jin, X. Fu, and H.-J. Kim, 2012: Reduction of the thermocline feedback associated with mean SST bias in ENSO simulation. Climate Dyn., 39, 1413–1430, doi:10.1007/s00382-011-1164-4.

    • Search Google Scholar
    • Export Citation

  • Xiang, B., B. Wang, A. Lauer, J.-Y. Lee, and Q. Ding, 2014: Upper tropospheric warming intensifies sea surface warming. Climate Dyn., 43, 259-270, doi:10.1007/s00382-013-1928-0.

    • Search Google Scholar
    • Export Citation

  • Xie, S.-P., C. Deser, G. A. Vecchi, J. Ma, H. Teng, and A. T. Wittenberg, 2010: Global warming pattern formation: Sea surface temperature and rainfall. J. Climate, 23, 966–986, doi:10.1175/2009JCLI3329.1.

    • Search Google Scholar
    • Export Citation

  • Xie, S.-P., B. Lu, and B. Xiang, 2013: Similar spatial patterns of climate responses to aerosol and greenhouse gas change. Nat. Geosci., 6, 828–832, doi:10.1038/ngeo1931.

    • Search Google Scholar
    • Export Citation

  • Zhao, M., I. M. Held, S.-J. Lin, and G. A. Vecchi, 2009: Simulations of global hurricane climatology, interannual variability, and response to global warming using a 50-km resolution GCM. J. Climate, 22, 6653–6678, doi:10.1175/2009JCLI3049.1.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1849 1111 291
PDF Downloads 342 71 4