Editorial Type:
Article
Article Type:
Research Article

Representation of African Easterly Waves in CMIP5 Models

Elinor R. Martin School of Meteorology, University of Oklahoma, Norman, Oklahoma

Search for other papers by Elinor R. Martin in
Current site
Google Scholar
PubMed Close
and
Chris Thorncroft Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, New York

Search for other papers by Chris Thorncroft in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Oct 2015
Collections:
Peter J. Lamb Special Collection: Climate Variability and Its Impacts
DOI:
https://doi.org/10.1175/JCLI-D-15-0145.1
Page(s):
7702–7715
Restricted access

Abstract

African easterly waves (AEWs) can act as seed disturbances for tropical cyclones (TCs) in the Atlantic, and changes in future AEW activity may have important consequences for development of TCs. The simulation of AEWs was investigated using output from phase 5 of the Coupled Model Intercomparison Project (CMIP5) suite of experiments, including coupled historical and future simulations and atmosphere only (AMIP) simulations. Large biases exist in the simulation of low- (850 hPa) and midlevel (700 hPa) eddy kinetic energy (EKE, a proxy for AEW activity) in AMIP and historical simulations. CMIP5 models simulate excessive EKE and deficient rainfall south of 17°N. The same biases exist in historical and AMIP models and are not a consequence of errors in sea surface temperatures. The models also struggle to accurately couple AEWs and rainfall, with little improvement from CMIP3 models. CMIP5 models are unable to propagate AEWs across the coast and into the Atlantic, which is shown to be related to the resolution of the Guinea Highlands. Future projections of the annual cycle of AEW activity show a reduction in late spring and early summer and a large increase between July and October that is consistent with rainfall projections in the Sahel, but large differences exists in future projections between high- and low-resolution models. The simulation of AEWs is challenging for CMIP5 models and must be further diagnosed in order to accurately predict future TC activity and rainfall in the Sahel.

Corresponding author address: Elinor R. Martin, School of Meteorology, University of Oklahoma, 120 David L Boren Blvd., Norman, OK 73072. E-mail: elinor.martin@ou.edu

This article is included in the In Honor of Peter J. Lamb special collection.

Abstract

African easterly waves (AEWs) can act as seed disturbances for tropical cyclones (TCs) in the Atlantic, and changes in future AEW activity may have important consequences for development of TCs. The simulation of AEWs was investigated using output from phase 5 of the Coupled Model Intercomparison Project (CMIP5) suite of experiments, including coupled historical and future simulations and atmosphere only (AMIP) simulations. Large biases exist in the simulation of low- (850 hPa) and midlevel (700 hPa) eddy kinetic energy (EKE, a proxy for AEW activity) in AMIP and historical simulations. CMIP5 models simulate excessive EKE and deficient rainfall south of 17°N. The same biases exist in historical and AMIP models and are not a consequence of errors in sea surface temperatures. The models also struggle to accurately couple AEWs and rainfall, with little improvement from CMIP3 models. CMIP5 models are unable to propagate AEWs across the coast and into the Atlantic, which is shown to be related to the resolution of the Guinea Highlands. Future projections of the annual cycle of AEW activity show a reduction in late spring and early summer and a large increase between July and October that is consistent with rainfall projections in the Sahel, but large differences exists in future projections between high- and low-resolution models. The simulation of AEWs is challenging for CMIP5 models and must be further diagnosed in order to accurately predict future TC activity and rainfall in the Sahel.

Corresponding author address: Elinor R. Martin, School of Meteorology, University of Oklahoma, 120 David L Boren Blvd., Norman, OK 73072. E-mail: elinor.martin@ou.edu

This article is included in the In Honor of Peter J. Lamb special collection.

Save
Cover Journal of Climate
Journal of Climate

  • Adachi, Y., and Coauthors, 2013: Basic performance of a new earth system model of the Meteorological Research Institute (MRI-ESM1). Pap. Meteor. Geophys., 64, 1–19, doi:10.2467/mripapers.64.1.

    • Search Google Scholar
    • Export Citation

  • Adler, R. F., and Coauthors, 2003: The version-2 global precipitation climatology project (GPCP) monthly precipitation analysis (1979–present). J. Hydrometeor., 4, 1147–1167, doi:10.1175/1525-7541(2003)004<1147:TVGPCP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Amante, C., and B. Eakins, 2009: ETOPO1 1 arc-minute global relief model: Procedures, data sources and analysis. NOAA Tech. Memo. NESDIS NGDC-24, 19 pp. [Available online at https://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/docs/ETOPO1.pdf.]

  • Arora, V., and Coauthors, 2011: Carbon emission limits required to satisfy future representative concentration pathways of greenhouse gases. Geophys. Res. Lett., 38, L05805, doi:10.1029/2010GL046270.

    • Search Google Scholar
    • Export Citation

  • Avila, L. A., and R. J. Pasch, 1992: Atlantic tropical systems of 1991. Mon. Wea. Rev., 120, 2688–2696, doi:10.1175/1520-0493(1992)120<2688:ATSO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Bentsen, M., and Coauthors, 2013: The Norwegian Earth System Model, NorESM1-M—Part 1: Description and basic evaluation of the physical climate. Geosci. Model Dev., 6, 687–720, doi:10.5194/gmd-6-687-2013.

    • Search Google Scholar
    • Export Citation

  • Berry, G., and C. Thorncroft, 2005: Case study of an intense African easterly wave. Mon. Wea. Rev., 133, 752–766, doi:10.1175/MWR2884.1.

    • Search Google Scholar
    • Export Citation

  • Bi, D., and Coauthors, 2013: The ACCESS coupled model: Description, control climate and evaluation. Aust. Meteor. Oceanogr. J., 63, 41–64.

    • Search Google Scholar
    • Export Citation

  • Biasutti, M., 2013: Forced Sahel rainfall trends in the CMIP5 archive. J. Geophys. Res. Atmos., 118, 1613–1623, doi:10.1002/jgrd.50206.

    • Search Google Scholar
    • Export Citation

  • Burpee, R. W., 1972: The origin and structure of easterly waves in the lower troposphere of North Africa. J. Atmos. Sci., 29, 77–90, doi:10.1175/1520-0469(1972)029<0077:TOASOE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Camargo, S. J., 2013: Global and regional aspects of tropical cyclone activity in the CMIP5 models. J. Climate, 26, 9880–9902, doi:10.1175/JCLI-D-12-00549.1.

    • Search Google Scholar
    • Export Citation

  • Camargo, S. J., A. Barnston, and S. Zebiak, 2005: A statistical assessment of tropical cyclone activity in atmospheric general circulation models. Tellus, 57A, 589–604, doi:10.1111/j.1600-0870.2005.00117.x.

    • Search Google Scholar
    • Export Citation

  • Carlson, T. N., 1969: Synoptic histories of three African disturbances that developed into Atlantic hurricanes. Mon. Wea. Rev., 97, 256–276, doi:10.1175/1520-0493(1969)097<0256:SHOTAD>2.3.CO;2.

    • Search Google Scholar
    • Export Citation

  • Chen, T.-C., 2006: Characteristics of African easterly waves depicted by ECMWF reanalyses for 1991–2000. Mon. Wea. Rev., 134, 3539–3566, doi:10.1175/MWR3259.1.

    • Search Google Scholar
    • Export Citation

  • Chen, T.-C., S.-Y. Wang, and A. J. Clark, 2008: North Atlantic hurricanes contributed by African easterly waves north and south of the African easterly jet. J. Climate, 21, 6767–6776, doi:10.1175/2008JCLI2523.1.

    • Search Google Scholar
    • Export Citation

  • Crétat, J., E. K. Vizy, and K. H. Cook, 2015: The relationship between African easterly waves and daily rainfall over West Africa: Observations and regional climate simulations. Climate Dyn., 44, 385–404, doi:10.1007/s00382-014-2120-x.

    • Search Google Scholar
    • Export Citation

  • Daloz, A. S., F. Chauvin, K. Walsh, S. Lavender, D. Abbs, and F. Roux, 2012: The ability of general circulation models to simulate tropical cyclones and their precursors over the North Atlantic main development region. Climate Dyn., 39, 1559–1576, doi:10.1007/s00382-012-1290-7.

    • Search Google Scholar
    • Export Citation

  • Donner, L., and Coauthors, 2011: The dynamical core, physical parameterizations, and basic simulation characteristics of the atmospheric component AM3 of the GFDL global coupled model CM3. J. Climate, 24, 3484–3519, doi:10.1175/2011JCLI3955.1.

    • Search Google Scholar
    • Export Citation

  • Dufresne, J.-L., and Coauthors, 2013: Climate change projections using the IPSL-CM5 earth system model: From CMIP3 to CMIP5. Climate Dyn., 40, 2123–2165, doi:10.1007/s00382-012-1636-1.

    • Search Google Scholar
    • Export Citation

  • Dunne, J. P., and Coauthors, 2012: GFDL’s ESM2 global coupled climate–carbon earth system models. Part I: Physical formulation and baseline simulation characteristics. J. Climate, 25, 6646–6665, doi:10.1175/JCLI-D-11-00560.1.

    • Search Google Scholar
    • Export Citation

  • Dwyer, J. G., S. J. Camargo, A. H. Sobel, M. Biasutti, K. A. Emanuel, G. A. Vecchi, M. Zhao, and M. K. Tippett, 2015: Projected twenty-first-century changes in the length of the tropical cyclone season. J. Climate, 28, 6181–6192, doi:10.1175/JCLI-D-14-00686.1.

    • Search Google Scholar
    • Export Citation

  • Emanuel, K. A., 2013: Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century. Proc. Natl. Acad. Sci. USA, 110, 12 219–12 224, doi:10.1073/pnas.1301293110.

    • Search Google Scholar
    • Export Citation

  • Gent, P., and Coauthors, 2011: The Community Climate System Model version 4. J. Climate, 24, 4973–4991, doi:10.1175/2011JCLI4083.1.

  • Giorgetta, M. A., and Coauthors, 2013: Climate and carbon cycle changes from 1850 to 2100 in MPI-ESM simulations for the coupled model intercomparison project phase 5. J. Adv. Model. Earth Syst., 5, 572–597, doi:10.1002/jame.20038.

    • Search Google Scholar
    • Export Citation

  • Gray, W., 1968: Global view of the origins of tropical disturbances and storms. Mon. Wea. Rev., 96, 669–700, doi:10.1175/1520-0493(1968)096<0669:GVOTOO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Harris, I., P. Jones, T. Osborn, and D. Lister, 2014: Updated high-resolution grids of monthly climatic observations—The CRU TS3.10 dataset. Int. J. Climatol., 34, 623–642, doi:10.1002/joc.3711.

    • Search Google Scholar
    • Export Citation

  • Hazeleger, W., and Coauthors, 2010: EC-Earth: A seamless earth-system prediction approach in action. Bull. Amer. Meteor. Soc., 91, 1357–1363, doi:10.1175/2010BAMS2877.1.

    • Search Google Scholar
    • Export Citation

  • Hopsch, S. B., C. D. Thorncroft, K. Hodges, and A. Aiyyer, 2007: West African storm tracks and their relationship to Atlantic tropical cyclones. J. Climate, 20, 2468–2483, doi:10.1175/JCLI4139.1.

    • Search Google Scholar
    • Export Citation

  • Hopsch, S. B., C. D. Thorncroft, and K. R. Tyle, 2010: Analysis of African easterly wave structures and their role in influencing tropical cyclogenesis. Mon. Wea. Rev., 138, 1399–1419, doi:10.1175/2009MWR2760.1.

    • Search Google Scholar
    • Export Citation

  • Janiga, M. A., and C. D. Thorncroft, 2013: Regional differences in the kinematic and thermodynamic structure of African easterly waves. Quart. J. Roy. Meteor. Soc., 139, 1598–1614, doi:10.1002/qj.2047.

    • Search Google Scholar
    • Export Citation

  • Ji, D., and Coauthors, 2014: Description and basic evaluation of Beijing Normal University Earth System Model (BNU-ESM) version 1. Geosci. Model Dev., 7, 2039–2064, doi:10.5194/gmd-7-2039-2014.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471, doi:10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Kiladis, G. N., C. D. Thorncroft, and N. M. J. Hall, 2006: Three-dimensional structure and dynamics of African easterly waves. Part I: Observations. J. Atmos. Sci., 63, 2212–2230, doi:10.1175/JAS3741.1.

    • Search Google Scholar
    • Export Citation

  • Kobayashi, S., and Coauthors, 2015: The JRA-55 reanalysis: General specifications and basic characteristics. J. Meteor. Soc. Japan, 93, 5–48, doi:10.2151/jmsj.2015-001.

    • Search Google Scholar
    • Export Citation

  • Landsea, C. W., 1993: A climatology of intense (or major) Atlantic hurricanes. Mon. Wea. Rev., 121, 1703–1713, doi:10.1175/1520-0493(1993)121<1703:ACOIMA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Leroux, S., N. M. J. Hall, and G. N. Kiladis, 2010: A climatological study of transient–mean-flow interactions over West Africa. Quart. J. Roy. Meteor. Soc., 136, 397–410, doi:10.1002/qj.474.

    • Search Google Scholar
    • Export Citation

  • Martin, E. R., and C. D. Thorncroft, 2014: The impact of the AMO on the West African monsoon annual cycle. Quart. J. Roy. Meteor. Soc., 140, 31–46, doi:10.1002/qj.2107.

    • Search Google Scholar
    • Export Citation

  • Martin, G., and Coauthors, 2011: The HadGEM2 family of Met Office unified model climate configurations. Geosci. Model Dev., 4, 723–757, doi:10.5194/gmd-4-723-2011.

    • Search Google Scholar
    • Export Citation

  • Mekonnen, A., C. D. Thorncroft, and A. R. Aiyyer, 2006: Analysis of convection and its association with African easterly waves. J. Climate, 19, 5405–5421, doi:10.1175/JCLI3920.1.

    • Search Google Scholar
    • Export Citation

  • Mizuta, R., and Coauthors, 2012: Climate simulations using MRI-AGCM3.2 with 20-km grid. J. Meteor. Soc. Japan, 90A, 233–258, doi:10.2151/jmsj.2012-A12.

    • Search Google Scholar
    • Export Citation

  • Pasch, R. J., L. A. Avila, and J.-G. Jiing, 1998: Atlantic tropical systems of 1994 and 1995: A comparison of a quiet season to a near-record-breaking one. Mon. Wea. Rev., 126, 1106–1123, doi:10.1175/1520-0493(1998)126<1106:ATSOAA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Pytharoulis, I., and C. Thorncroft, 1999: The low-level structure of African easterly waves in 1995. Mon. Wea. Rev., 127, 2266–2280, doi:10.1175/1520-0493(1999)127<2266:TLLSOA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Reed, R., A. Hollingsworth, W. Heckley, and F. Delsol, 1988: An evaluation of the performance of the ECMWF operational system in analyzing and forecasting easterly wave disturbances over Africa and the tropical Atlantic. Mon. Wea. Rev., 116, 824–865, doi:10.1175/1520-0493(1988)116<0824:AEOTPO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Richter, I., S.-P. Xie, S. K. Behera, T. Doi, and Y. Masumoto, 2014: Equatorial Atlantic variability and its relation to mean state biases in CMIP5. Climate Dyn., 42, 171–188, doi:10.1007/s00382-012-1624-5.

    • Search Google Scholar
    • Export Citation

  • Roehrig, R., D. Bouniol, F. Guichard, F. Hourdin, and J.-L. Redelsperger, 2013: The present and future of the West African monsoon: A process-oriented assessment of CMIP5 simulations along the AMMA transect. J. Climate, 26, 6471–6505, doi:10.1175/JCLI-D-12-00505.1.

    • Search Google Scholar
    • Export Citation

  • Rotstayn, L., M. Collier, Y. Feng, H. Gordon, S. O’Farrell, I. Smith, and J. Syktus, 2010: Improved simulation of Australian climate and ENSO-related rainfall variability in a GCM with an interactive aerosol treatment. Int. J. Climatol., 30, 1067–1088, doi:10.1002/joc.1952.

    • Search Google Scholar
    • Export Citation

  • Ruti, P. M., and A. Dell’Aquila, 2010: The twentieth century African easterly waves in reanalysis systems and IPCC simulations, from intra-seasonal to inter-annual variability. Climate Dyn., 35, 1099–1117, doi:10.1007/s00382-010-0894-z.

    • Search Google Scholar
    • Export Citation

  • Saha, S., and Coauthors, 2010: The NCEP Climate Forecast System reanalysis. Bull. Amer. Meteor. Soc., 91, 1015–1057, doi:10.1175/2010BAMS3001.1.

    • Search Google Scholar
    • Export Citation

  • Scoccimarro, E., and Coauthors, 2011: Effects of tropical cyclones on ocean heat transport in a high-resolution coupled general circulation model. J. Climate, 24, 4368–4384, doi:10.1175/2011JCLI4104.1.

    • Search Google Scholar
    • Export Citation

  • Simmons, A., S. Uppala, D. Dee, and S. Kobayashi, 2007: ERA-Interim: New ECMWF reanalysis products from 1989 onwards. ECMWF Newsletter, No. 110, ECMWF, Reading, United Kingdom, 25–35.

  • Skinner, C. B., and N. S. Diffenbaugh, 2013: The contribution of African easterly waves to monsoon precipitation in the CMIP3 ensemble. J. Geophys. Res. Atmos., 118, 3590–3609, doi:10.1002/jgrd.50363.

    • Search Google Scholar
    • Export Citation

  • Skinner, C. B., and N. S. Diffenbaugh, 2014: Projected changes in African easterly wave intensity and track in response to greenhouse forcing. Proc. Natl. Acad. Sci., 111, 6882–6887, doi:10.1073/pnas.1319597111.

    • Search Google Scholar
    • Export Citation

  • Thorncroft, C. D., and K. I. Hodges, 2001: African easterly wave variability and its relationship to Atlantic tropical cyclone activity. J. Climate, 14, 1166–1179, doi:10.1175/1520-0442(2001)014<1166:AEWVAI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Thorncroft, C. D., N. M. J. Hall, and G. N. Kiladis, 2008: Three-dimensional structure and dynamics of African easterly waves. Part III: Genesis. J. Atmos. Sci., 65, 3596–3607, doi:10.1175/2008JAS2575.1.

    • Search Google Scholar
    • Export Citation

  • Ventrice, M. J., C. D. Thorncroft, and M. A. Janiga, 2012: Atlantic tropical cyclogenesis: A three-way interaction between an African easterly wave, diurnally varying convection, and a convectively coupled atmospheric kelvin wave. Mon. Wea. Rev., 140, 1108–1124, doi:10.1175/MWR-D-11-00122.1.

    • Search Google Scholar
    • Export Citation

  • Voldoire, A., and Coauthors, 2013: The CNRM-CM5.1 global climate model: Description and basic evaluation. Climate Dyn., 40, 2091–2121, doi:10.1007/s00382-011-1259-y.

    • Search Google Scholar
    • Export Citation

  • Volodin, E., N. Dianskii, and A. Gusev, 2010: Simulating present-day climate with the INMCM4.0 coupled model of the atmospheric and oceanic general circulations. Izv., Atmos. Oceanic Phys., 46, 414–431, doi:10.1134/S000143381004002X.

    • Search Google Scholar
    • Export Citation

  • von Salzen, K., and Coauthors, 2013: The Canadian fourth generation atmospheric global climate model (CanAM4). Part I: Representation of physical processes. Atmos.–Ocean, 51, 104–125, doi:10.1080/07055900.2012.755610.

    • Search Google Scholar
    • Export Citation

  • Watanabe, M., and Coauthors, 2010: Improved climate simulation by MIROC5: Mean states, variability, and climate sensitivity. J. Climate, 23, 6312–6335, doi:10.1175/2010JCLI3679.1.

    • Search Google Scholar
    • Export Citation

  • Xie, P., and P. Arkin, 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc., 78, 2539–2558, doi:10.1175/1520-0477(1997)078<2539:GPAYMA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Xin, X., T. Wu, and J. Zhang, 2012: Introductions to the CMIP5 simulations conducted by the BCC climate system model (in Chinese). Adv. Climate Change Res., 8, 378–382.

    • Search Google Scholar
    • Export Citation

  • Yukimoto, S., and Coauthors, 2012: A new global climate model of the Meteorological Research Institute: MRI-CGCM3: Model description and basic performance. J. Meteor. Soc. Japan, 90A, 23–64, doi:10.2151/jmsj.2012-A02.

    • 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

  • Zhou, T., F. Song, and X. Chen, 2013: Historical evolution of global and regional surface air temperature simulated by FGOALS-s2 and FGOALS-g2: How reliable are the model results? Adv. Atmos. Sci., 30, 638–657, doi:10.1007/s00376-013-2205-1.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 768 317 37
PDF Downloads 331 64 10