Editorial Type:
Article
Article Type:
Research Article

Simulations of the West African Monsoon with a Superparameterized Climate Model. Part I: The Seasonal Cycle

Rachel R. McCrary National Center for Atmospheric Research,* Boulder, Colorado

Search for other papers by Rachel R. McCrary in
Current site
Google Scholar
PubMed Close
,
David A. Randall Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

Search for other papers by David A. Randall in
Current site
Google Scholar
PubMed Close
, and
Cristiana Stan Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, Virginia, and Center for Ocean–Land–Atmosphere Studies, Calverton, Maryland

Search for other papers by Cristiana Stan in
Current site
Google Scholar
PubMed Close
Print Publication:
15 Nov 2014
DOI:
https://doi.org/10.1175/JCLI-D-13-00676.1
Page(s):
8303–8322
Restricted access

Abstract

The West African monsoon seasonal cycle is simulated with two coupled general circulation models: the Community Climate System Model (CCSM), which uses traditional convective parameterizations, and the “superparameterized” CCSM (SP-CCSM), in which the atmospheric parameterizations have been replaced with an embedded cloud-resolving model. Compared to CCSM, SP-CCSM better represents the magnitude and spatial patterns of summer monsoon precipitation over West Africa. Most importantly, the region of maximum precipitation is shifted from the Gulf of Guinea in CCSM (not realistic) to over the continent in SP-CCSM. SP-CCSM also develops its own biases—namely, excessive rainfall along the Guinean coast in summer. Biases in rainfall from both models are linked to a misrepresentation of the equatorial Atlantic cold tongue. Warm sea surface temperature (SST) biases are linked to westerly trade wind biases and convection within the intertropical convergence zone. Improved SST biases in SP-CCSM are linked to increased tropospheric warming associated with convection. A weaker-than-observed Saharan heat low is found in both models, which explains why the main band of precipitation does not penetrate as far northward as observed. The latitude–height position of the African easterly jet (AEJ) is comparable to observations in both models, but the meridional temperature and moisture gradients and the strength of the jet are too weak in SP-CCSM and too strong in CCSM. Differences in the AEJ are hypothesized to be influenced by the contrasting representation of African easterly waves in both models; no wave activity is found in CCSM, and strong waves are found in SP-CCSM.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Rachel R. McCrary, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307. E-mail: rmccrary@ucar.edu

Abstract

The West African monsoon seasonal cycle is simulated with two coupled general circulation models: the Community Climate System Model (CCSM), which uses traditional convective parameterizations, and the “superparameterized” CCSM (SP-CCSM), in which the atmospheric parameterizations have been replaced with an embedded cloud-resolving model. Compared to CCSM, SP-CCSM better represents the magnitude and spatial patterns of summer monsoon precipitation over West Africa. Most importantly, the region of maximum precipitation is shifted from the Gulf of Guinea in CCSM (not realistic) to over the continent in SP-CCSM. SP-CCSM also develops its own biases—namely, excessive rainfall along the Guinean coast in summer. Biases in rainfall from both models are linked to a misrepresentation of the equatorial Atlantic cold tongue. Warm sea surface temperature (SST) biases are linked to westerly trade wind biases and convection within the intertropical convergence zone. Improved SST biases in SP-CCSM are linked to increased tropospheric warming associated with convection. A weaker-than-observed Saharan heat low is found in both models, which explains why the main band of precipitation does not penetrate as far northward as observed. The latitude–height position of the African easterly jet (AEJ) is comparable to observations in both models, but the meridional temperature and moisture gradients and the strength of the jet are too weak in SP-CCSM and too strong in CCSM. Differences in the AEJ are hypothesized to be influenced by the contrasting representation of African easterly waves in both models; no wave activity is found in CCSM, and strong waves are found in SP-CCSM.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Rachel R. McCrary, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307. E-mail: rmccrary@ucar.edu
Save
Cover Journal of Climate
Journal of Climate

  • Alley, B., and Coauthors, 2007: Summary for policymakers. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 1–18. [Available online at http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf.]

    • Search Google Scholar
    • Export Citation

  • Baron, C., B. Sultan, M. Balme, B. Sarr, S. Traore, T. Lebel, S. Janicot, and M. Dingkuhn, 2005: From GCM grid cell to agricultural plot: Scale issues affecting modelling of climate impact. Philos. Trans. Roy. Soc. London, B360, 2095–2108, doi:10.1098/rstb.2005.1741.

    • Search Google Scholar
    • Export Citation

  • Benedict, J. J., and D. A. Randall, 2009: Structure of the Madden–Julian oscillation in the superparameterized CAM. J. Atmos. Sci., 66, 3277–3296, doi:10.1175/2009JAS3030.1.

    • Search Google Scholar
    • Export Citation

  • Benedict, J. J., and D. A. Randall, 2011: Impacts of idealized air–sea coupling on Madden–Julian oscillation structure in the superparameterized CAM. J. Atmos. Sci., 68, 1990–2008, doi:10.1175/JAS-D-11-04.1.

    • Search Google Scholar
    • Export Citation

  • Berry, G., and C. D. 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

  • Boko, M., and Coauthors, 2007: Africa. Climate Change 2007: Impacts, Adaptation and Vulnerability, M.L. Parry et al., Eds., Cambridge University Press, 433–467. [Available online at http://www.ipcc.ch/pdf/assessment-report/ar4/wg2/ar4-wg2-chapter9.pdf.]

  • Bonan, G. B., K. W. Oleson, M. Vertenstein, S. Levis, X. Zeng, Y. Dai, R. E. Dickinson, and Z.-L. Yang, 2002: The land surface climatology of the community land model coupled to the NCAR community climate model. J. Climate, 15, 3123–3149, doi:10.1175/1520-0442(2002)015<3123:TLSCOT>2.0.CO;2.

    • 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

  • Caniaux, G., H. Giordani, J.-L. Redelsperger, F. Guichard, E. Key, and M. Wade, 2011: Coupling between the Atlantic cold tongue and the West African monsoon in boreal spring and summer. J. Geophys. Res., 116, C04003, doi:10.1029/2010JC006570.

    • Search Google Scholar
    • Export Citation

  • Chang, C.-Y., J. A. Carton, S. A. Grodsky, and S. Nigam, 2007: Seasonal climate of the tropical Atlantic sector in the NCAR Community Climate System Model 3: Error structure and probable causes of errors. J. Climate, 20, 1053–1070, doi:10.1175/JCLI4047.1.

    • Search Google Scholar
    • Export Citation

  • Coëtlogon, G., S. Janicot, and A. Lazar, 2010: Intraseasonal variability of the ocean–atmosphere coupling in the Gulf of Guinea during boreal spring and summer. Quart. J. Roy. Meteor. Soc.,136, 426–441. doi:10.1002/qj.554.

  • Collins, W. D., and Coauthors, 2006: The Community Climate System Model version 3 (CCSM3). J. Climate, 19, 2122–2143, doi:10.1175/JCLI3761.1.

    • Search Google Scholar
    • Export Citation

  • Cook, K. H., 1999: Generation of the African easterly jet and its role in determining West African precipitation. J. Climate, 12, 1165–1184, doi:10.1175/1520-0442(1999)012<1165:GOTAEJ>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Cook, K. H., and E. K. Vizy, 2006: Coupled model simulations of the West African monsoon system: Twentieth- and twenty-first-century simulations. J. Climate, 19, 3681–3703, doi:10.1175/JCLI3814.1.

    • Search Google Scholar
    • Export Citation

  • Cook, K. H., G. A. Meehl, and J. M. Arblaster, 2012: Monsoon regimes and processes in CCSM4. Part II: African and American monsoon systems. J. Climate, 25, 2609–2621, doi:10.1175/JCLI-D-11-00185.1.

    • Search Google Scholar
    • Export Citation

  • Davey, M., and Coauthors, 2002: STOIC: A study of coupled model climatology and variability in tropical ocean regions. Climate Dyn., 18, 403–420, doi:10.1007/s00382-001-0188-6.

    • 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

  • DeMott, C. A., D. A. Randall, and M. Khairoutdinov, 2007: Convective precipitation variability as a tool for general circulation model analysis. J. Climate, 20, 91–112, doi:10.1175/JCLI3991.1.

    • Search Google Scholar
    • Export Citation

  • DeMott, C. A., C. Stan, D. A. Randall, J. L. Kinter III, and M. Khairoutdinov, 2011: The Asian monsoon in the superparameterized CCSM and its relationship to tropical wave activity. J. Climate, 24, 5134–5156, doi:10.1175/2011JCLI4202.1.

    • Search Google Scholar
    • Export Citation

  • DeMott, C. A., C. Stan, and D. A. Randall, 2013: Northward propagation mechanisms of the Boreal summer intraseasonal oscillation in the ERA-Interim and SP-CCSM. J. Climate, 26, 1973–1992, doi:10.1175/JCLI-D-12-00191.1.

    • Search Google Scholar
    • Export Citation

  • Fink, A. H., and A. Reiner, 2003: Spatiotemporal variability of the relation between African Easterly Waves and West African Squall Lines in 1998 and 1999. J. Geophys. Res., 108, 4332, doi:10.1029/2002JD002816.

    • Search Google Scholar
    • Export Citation

  • Foltz, G. R., S. A. Grodsky, J. A. Carton, and M. J. McPhaden, 2003: Seasonal mixed layer heat budget of the tropical Atlantic Ocean. J. Geophys. Res., 108, 3146, doi:10.1029/2002JC001584.

    • Search Google Scholar
    • Export Citation

  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy Meteor. Soc., 106, 447–462, doi:10.1002/qj.49710644905.

    • Search Google Scholar
    • Export Citation

  • Grabowski, W. W., 2001: Coupling cloud processes with the large-scale dynamics using the cloud-resolving convection parameterization (CRCP). J. Atmos. Sci., 58, 978–997, doi:10.1175/1520-0469(2001)058<0978:CCPWTL>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Grabowski, W. W., and P. K. Smolarkiewicz, 1999: CRCP: A Cloud Resolving Convection Parameterization for modeling the tropical convecting atmosphere. Physica D, 133, 171–178, doi:10.1016/S0167-2789(99)00104-9.

    • Search Google Scholar
    • Export Citation

  • Grodsky, S. A., J. A. Carton, and S. Nigam, 2003: Near surface westerly wind jet in the Atlantic ITCZ. Geophys. Res. Lett., 30, 2009, doi:10.1029/2003GL017867.

    • Search Google Scholar
    • Export Citation

  • Gu, G., and R. F. Adler, 2004: Seasonal evolution and variability associated with the West African monsoon system. J. Climate, 17, 3364–3377, doi:10.1175/1520-0442(2004)017<3364:SEAVAW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Hack, J. J., 1994: Parameterization of moist convection in the National Center for Atmospheric Research community climate model (CCM2). J. Geophys. Res., 99, 5551–5568, doi:10.1029/93JD03478.

    • Search Google Scholar
    • Export Citation

  • Hagos, S. M., and K. H. Cook, 2007: Dynamics of the West African monsoon jump. J. Climate, 20, 5264–5284, doi:10.1175/2007JCLI1533.1.

  • Hall, N. M. J., and P. Peyrillé, 2006: Dynamics of the West African monsoon. J. Phys. IV France, 139, 81–99, doi:10.1051/jp4:2006139007.

    • Search Google Scholar
    • Export Citation

  • Hall, N. M. J., G. N. Kiladis, and C. D. Thorncroft, 2006: Three-dimensional structure and dynamics of African easterly waves. Part II: Dynamical modes. J. Atmos. Sci., 63, 2231–2245, doi:10.1175/JAS3742.1.

    • Search Google Scholar
    • Export Citation

  • Hou, A. Y., and R. S. Lindzen, 1992: The influence of concentrated heating on the Hadley circulation. J. Atmos. Sci., 49, 1233–1241, doi:10.1175/1520-0469(1992)049<1233:TIOCHO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Hsieh, J.-S., and K. H. Cook, 2007: A study of the energetics of African easterly waves using a regional climate model. J. Atmos. Sci., 64, 421–440, doi:10.1175/JAS3851.1.

    • Search Google Scholar
    • Export Citation

  • Huffman, G. J., and Coauthors, 2007: The TRMM Multisatellite Precipitation Analysis: Quasi-global, multiyear, combined-sensor precipitation estimates at fine scale. J. Hydrometeor., 8, 38–55, doi:10.1175/JHM560.1.

    • Search Google Scholar
    • Export Citation

  • James, R., and R. Washington, 2013: Changes in African temperature and precipitation associated with degrees of global warming. Climatic Change, 117, 859–872, doi:10.1007/s10584-012-0581-7.

    • Search Google Scholar
    • Export Citation

  • Joiner, E., D. Kennedo, and J. Sampson, 2012: Vulnerability to climate change in West Africa: Adaptive capacity in the regional context. Climate Change and African Political Stability Student Working Paper 4, 43 pp.

  • Khairoutdinov, M. F., and D. A. Randall, 2001: A cloud resolving model as a cloud parameterization in the NCAR Community Climate System Model: Preliminary results. Geophys. Res. Lett., 28, 3617–3620, doi:10.1029/2001GL013552.

    • Search Google Scholar
    • Export Citation

  • Khairoutdinov, M. F., and D. A. Randall, 2003: Cloud-resolving modeling of the ARM summer 1997 IOP: Model formulation, results, uncertainties, and sensitivities. J. Atmos. Sci., 60, 607–625, doi:10.1175/1520-0469(2003)060<0607:CRMOTA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Khairoutdinov, M. F., D. A. Randall, and C. DeMott, 2005: Simulations of the atmospheric general circulation using a cloud-resolving model as a superparameterization of physical processes. J. Atmos. Sci., 62, 2136–2154, doi:10.1175/JAS3453.1.

    • Search Google Scholar
    • Export Citation

  • Khairoutdinov, M. F., C. DeMott, and D. A. Randall, 2008: Evaluation of the simulated interannual and subseasonal variability in an AMIP-style simulation using the CSU Multiscale Modeling Framework. J. Climate, 21, 413–431, doi:10.1175/2007JCLI1630.1.

    • 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

  • Laing, A. G., R. Carbone, V. Levizzani, and J. Tuttle, 2008: The propagation and diurnal cycles of deep convection in northern tropical Africa. Quart. J. Roy. Meteor. Soc.,134, 93–109, doi:10.1002/qj.194.

  • Lavaysse, C., C. Flamant, S. Janicot, D. J. Parker, J.-P. Lafore, B. Sultan, and J. Pelon, 2009: Seasonal evolution of the West African heat low: A climatological perspective. Climate Dyn., 33, 313–330, doi:10.1007/s00382-009-0553-4.

    • Search Google Scholar
    • Export Citation

  • Le Barbé, L., T. Lebel, and D. Tapsoba, 2002: Rainfall variability in West Africa during the years 1950–90. J. Climate, 15, 187–202, doi:10.1175/1520-0442(2002)015<0187:RVIWAD>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Leroux, S., and N. M. J. Hall, 2009: On the relationship between African easterly waves and the African easterly jet. J. Atmos. Sci., 66, 2303–2316, doi:10.1175/2009JAS2988.1.

    • Search Google Scholar
    • Export Citation

  • Leroux, S., N. M. J. Hall, and G. N. Kiladis, 2010: 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

  • Levitus, S., and Coauthors, 1998: Introduction. World Ocean Database 1998, Vol. 1, NOAA Atlas NESDIS 18, 346 pp.

  • Liebmann, B., I. Bladé, G. N. Kiladis, L. M. V. Carvalho, G. Senay, D. Allured, S. Leroux, and C. Funk, 2012: Seasonality of African precipitation from 1996 to 2009. J. Climate, 25, 4304–4322, doi:10.1175/JCLI-D-11-00157.1.

    • Search Google Scholar
    • Export Citation

  • Lin, X., and R. H. Johnson, 1996: Kinematic and thermodynamic characteristics of the flow over the western Pacific warm pool during TOGA COARE. J. Atmos. Sci., 53, 695–715, doi:10.1175/1520-0469(1996)053<0695:KATCOT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • McCrary, R. R., 2012: Seasonal, synoptic, and intraseasonal variability of the West African monsoon. Ph.D. dissertation, Colorado State University, 157 pp. [Available online at http://kiwi.atmos.colostate.edu/rr/groupPIX/rachel/McCrary_Rachel.pdf.]

  • McCrary, R. R., D. A. Randall, and C. Stan, 2014: Simulations of the West African monsoon with a superparameterized climate model. Part II: African easterly waves. J. Climate, 27, 8323–8341, doi:10.1175/JCLI-D-13-00677.1.

  • Meehl, G. A., C. Covey, T. Delworth, M. Latif, B. McAvaney, J. F. B. Mitchell, R. J. Stouffer, and K. E. Taylor, 2007: The WCRP CMIP3 multimodel dataset: A new era in climate change research. Bull. Amer. Meteor. Soc., 88, 1383–1394, doi:10.1175/BAMS-88-9-1383.

    • 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

  • Mitchell, T., and J. M. Wallace, 1992: The annual cycle in equatorial convection and sea surface temperature. J. Climate, 5, 1140–1156, doi:10.1175/1520-0442(1992)005<1140:TACIEC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Nguyen, H., C. D. Thorncroft, and C. Zhang, 2011: Guinean coastal rainfall of the West African Monsoon. Quart. J. Roy. Meteor. Soc., 137,1828–1840, doi:10.1002/qj.867.

    • Search Google Scholar
    • Export Citation

  • Nicholson, S. E., 2000: The nature of rainfall variability over Africa on time scales of decades to millenia. Global Planet. Change, 26, 137–158, doi:10.1016/S0921-8181(00)00040-0.

    • Search Google Scholar
    • Export Citation

  • Okumura, Y., and S.-P. Xie, 2004: Interaction of the Atlantic equatorial cold tongue and the African monsoon. J. Climate, 17, 3589–3602, doi:10.1175/1520-0442(2004)017<3589:IOTAEC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Patricola, C. M., M. Li, Z. Xu, P. Chang, R. Saravanan, and J.-S. Hsieh, 2012: An investigation of tropical Atlantic bias in a high-resolution coupled regional climate model. Climate Dyn., 39, 2443–2463, doi:10.1007/s00382-012-1320-5.

    • Search Google Scholar
    • Export Citation

  • Pritchard, M. S., M. W. Moncrieff, and R. C. J. Somerville, 2011: Orogenic propagating precipitation systems over the United States in a global climate model with embedded explicit convection. J. Atmos. Sci., 68, 1821–1840, doi:10.1175/2011JAS3699.1.

    • Search Google Scholar
    • Export Citation

  • Pu, B., and K. H. Cook, 2010: Dynamics of the West African westerly jet. J. Climate, 23, 6263–6276, doi:10.1175/2010JCLI3648.1.

  • Ramel R., H. Gallée, and C. Messager, 2006: On the northward shift of the West African monsoon. Climate Dyn., 26, 429–440, doi:10.1007/s00382-005-0093-5.

    • Search Google Scholar
    • Export Citation

  • Randall, D., M. Khairoutdinov, A. Arakawa, and W. Grabowski, 2003: Breaking the cloud parameterization deadlock. Bull. Amer. Meteor. Soc., 84,1547–1564, doi:10.1175/BAMS-84-11-1547.

    • Search Google Scholar
    • Export Citation

  • Reynolds, R. W., T. M. Smith, C. Liu, D. B. Chelton, K. S. Casey, and M. G. Schlax, 2007: Daily high-resolution-blended analyses for sea surface temperature. J. Climate, 20, 5473–5496, doi:10.1175/2007JCLI1824.1.

    • Search Google Scholar
    • Export Citation

  • Richter, I., and S.-P. Xie, 2008: On the origin of equatorial Atlantic biases in coupled general circulation models. Climate Dyn., 31, 587–598, doi:10.1007/s00382-008-0364-z.

    • Search Google Scholar
    • Export Citation

  • Richter, I., S.-P. Xie, A. T. Wittenberg, and Y. Masumoto, 2012: Tropical Atlantic biases and their relation to surface wind stress and terrestrial precipitation. Climate Dyn., 38, 985–1001, doi:10.1007/s00382-011-1038-9.

    • 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

  • 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

  • Smith, R., and P. Gent, Eds., 2002: Reference manual for the Parallel Ocean Program (POP): Ocean component of the Community Climate System Model (CCSM2.0 and 3.0). Los Alamos National Laboratory Tech. Rep. LAUR-02-2484, 75 pp. [Available online at http://www.cesm.ucar.edu/models/ccsm3.0/pop/doc/manual.pdf.]

  • Stan, C., M. Khairoutdinov, C. A. DeMott, V. Krishnamurthy, D. M. Straus, D. A. Randall, J. L. Kinter III, and J. Shukla, 2010: An ocean–atmosphere climate simulation with an embedded cloud resolving model. Geophys. Res. Lett., 37, L01702, doi:10.1029/2009GL040822.

    • Search Google Scholar
    • Export Citation

  • Sultan, B., and S. Janicot, 2003: The West African monsoon dynamics. Part II: The “preonset” and “onset” of the summer monsoon. J. Climate., 16, 3407–3427, doi:10.1175/1520-0442(2003)016,3407:TWAMDP.2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sultan, B., S. Janicot, and A. Diedhiou, 2003: The West African monsoon dynamics. Part I: Documentation of intraseasonal variability. J. Climate, 16, 3389–3406, doi:10.1175/1520-0442(2003)016<3389:TWAMDP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sundqvist, H., 1988: Parameterization of condensation and associated clouds in models for weather prediction and general circulation simulation. Physically-Based Modelling and Simulation of Climate and Climate Change, M. E. Schlesinger, Ed., Kluwer Academic, 433–461.

  • 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

  • Thayer-Calder, K., and D. A. Randall, 2009: The role of convective moistening in the Madden–Julian oscillation. J. Atmos. Sci., 66, 3297–3312, doi:10.1175/2009JAS3081.1.

    • Search Google Scholar
    • Export Citation

  • Thorncroft, C. D., and M. Blackburn, 1999: Maintenance of the African easterly jet. Quart. J. Roy. Meteor. Soc., 125, 763–786, doi:10.1002/qj.49712555502.

    • 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

  • Thorncroft, C. D., H. Nguyen, C. Zhang, and P. Peyrillé, 2011: Annual cycle of the West African monsoon: Regional circulations and associated water vapour transport. Quart. J. Roy. Meteor. Soc.,137, 129–147, doi:10.1002/qj.728.

    • Search Google Scholar
    • Export Citation

  • Vizy, E. K., and K. H. Cook, 2001: Mechanisms by which Gulf of Guinea and eastern North Atlantic sea surface temperatures can influence African rainfall. J. Climate, 14, 795–821, doi:10.1175/1520-0442(2001)014<0795:MBWGOG>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Wu, M.-L. C., O. Reale, S. D. Schubert, M. J. Suarez, R. D. Koster, and P. J. Pegion, 2009: African easterly jet: Structure and maintenance. J. Climate, 22, 4459–4480, doi:10.1175/2009JCLI2584.1.

    • Search Google Scholar
    • Export Citation

  • Xie, S.-P., and J. A. Carton, 2004: Tropical Atlantic variability: Patterns, mechanisms, and impacts. Earth’s Climate: The Ocean-Atmosphere Interaction, Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 121–142.

  • Zermeño-Diaz, D. M., and C. Zhang, 2013: Possible root causes of surface westerly biases over the equatorial Atlantic in global climate models. J. Climate, 26, 8154–8168, doi:10.1175/JCLI-D-12-00226.1.

    • Search Google Scholar
    • Export Citation

  • Zhang, C., P. Woodworth, and G. Gu, 2006: The seasonal cycle in the lower troposphere over West Africa from sounding observations. Quart. J. Roy. Meteor. Soc., 132, 2559–2582, doi:10.1256/qj.06.23.

    • Search Google Scholar
    • Export Citation

  • Zhang, G. J., and N. A. McFarlane, 1995: Role of convective scale momentum transport in climate simulation. J. Geophys. Res., 100, 1417–1426, doi:10.1029/94JD02519.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 820 563 111
PDF Downloads 194 46 7