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Extremes in East African hydroclimate and links to Indo-Pacific variability on interannual to decadal timescales

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Abstract

East African hydroclimate exhibits considerable variability across a range of timescales, with implications for its population that depends on the region’s two rainy seasons. Recent work demonstrated that current state-of-the-art climate models consistently underestimate the long rains in boreal spring over the Horn of Africa while overestimating the short rains in autumn. This inability to represent the seasonal cycle makes it problematic for climate models to project changes in East African precipitation. Here we consider whether this bias also has implications for understanding interannual and decadal variability in the East African long and short rains. Using a consistent framework with an unforced multi-century global coupled climate model simulation, the role of Indo-Pacific variability for East African rainfall is compared across timescales and related to observations. The dominant driver of East African rainfall anomalies critically depends on the timescale under consideration: Interannual variations in East African hydroclimate coincide with significant sea surface temperature (SST) anomalies across the Indo-Pacific, including those associated with the El Niño-Southern Oscillation (ENSO) in the eastern Pacific, and are linked to changes in the Walker circulation, regional winds and vertical velocities over East Africa. Prolonged drought/pluvial periods in contrast exhibit anomalous SST predominantly in the Indian Ocean and Indo-Pacific warm pool (IPWP) region, while eastern Pacific anomalies are insignificant. We assessed dominant frequencies in Indo-Pacific SST and found the eastern equatorial Pacific dominated by higher-frequency variability in the ENSO band, while the tropical Indian Ocean and IPWP exhibit lower-frequency variability beyond 10 years. This is consistent with the different contribution to regional precipitation anomalies for the eastern Pacific versus Indian Ocean and IPWP on interannual and decadal timescales, respectively. In the model, the dominant low-frequency signal seen in the observations in the Indo-Pacific is not well-represented as it instead exhibits overly strong variability on subdecadal timescales. The overly strong ENSO-teleconnection likely contributes to the overestimated role of the short rains in the seasonal cycle in the model compared to observations.

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References

  • Awange JL, Ferreira VG, Forootan E, Khandu SA, Andam-Akorful NO, Agutu He XF (2016) Uncertainties in remotely sensed precipitation data over Africa. Int J Climatol 36:303–323

    Article  Google Scholar 

  • Awange JL, Forootan E, Kuhn M, Kusche J, Heck B (2014) Water storage changes and climate variability within the Nile Basin between 2002 and 2011. Adv Water Resour 73:1–15

    Article  Google Scholar 

  • Bahaga TK, Tsidu GM, Kucharski F, Diro GT (2015) Potential predictability of the sea-surface temperature forced equatorial East African short rains interannual variability in the 20th century. Quart J R Meteorol Soc 686:16–26

    Article  Google Scholar 

  • Behera SK, Luo J-J, Masson S, Delecluse P, Gualdi S, Navarra A, Yamagata T (2005) Paramount impact of the Indian Ocean Dipole on the East African short rains: A CGCM study. J Clim 18:4514–4530

    Article  Google Scholar 

  • Birkett C, Murtugudde R, Allan R (1999) Indian Ocean climate event brings floods to East Africa’s lakes and the Sudd Marsh. Geophys Res Lett 26(8):1031–1034

    Article  Google Scholar 

  • Black E, Slingo J, Sperber KR (2003) An observational study of the relationship between excessively strong short rains in coastal East Africa and Indian Ocean SST. Mon Weather Rev 131:74–94

    Article  Google Scholar 

  • Briegleb B, Bitz C, Hunke E, Lipscomb W, Holland M, Schramm J, Moritz R (2004) Scientific description of the sea ice component in the Community Climate System Model, version 3. Tech. rep., NCAR Technical Report No. NCAR/TN-463+STR

  • Camberlin P, Okoola RE (2003) The onset and cessation of the “long rains” in eastern Africa and their interannual variability. Theor Appl Climatol 75:43–54

    Google Scholar 

  • Christensen JH et al (2013) Climate phenomena and their relevance for future regional climate change. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Stocker TF, Qin D, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, and P. M. Midgley, Eds., Cambridge University Press, Cambridge, UK, 1217–1308

  • Compo GP et al (2011) The twentieth century reanalysis project. Quart J R Meteorol Soc 137:1–28

    Article  Google Scholar 

  • Conway DHCDR, and Persechino A (2007) GCM simulations of the Indian Ocean dipole influence on East African rainfall: Present and future. Geophysical Research Letters 34: doi:10.1029/2006GL027 597

  • Cook KH, Vizy EK (2013) Projected changes in East African rainy seasons. J Clim 26:5931–5948

    Article  Google Scholar 

  • Dai A (2006) Precipitation characteristics in eighteen coupled climate models. J Clim 19:4605–4630

    Article  Google Scholar 

  • Danabasoglu G, Bates SC, Briegleb BP, Jayne SR, Jochum M, Large WG, Peacock S, Yeager SG (2012) The CCSM4 ocean component. J Clim 25:1361–1389

    Article  Google Scholar 

  • Danabasoglu G, Ferrari R, McWilliams JC (2008) Sensitivity of an ocean general circulation model to a parameterization of near-surface eddy fluxes. J Clim 21:1192–1208

    Article  Google Scholar 

  • Danabasoglu G, Marshall J (2007) Effects of vertical variations of thickness diffusivity in an ocean general circulation model. Ocean Model 18:122–141

    Article  Google Scholar 

  • England MH et al (2014) Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus. Nat Clim Change 4:222–227

    Article  Google Scholar 

  • Fox-Kemper B et al (2011) Parameterization of mixed layer eddies. Part III: implementation and impact in global ocean climate simulations. Ocean Model 39:61–78

    Article  Google Scholar 

  • Funk C, Dettinger MD, Michaelsen JC, Verdin JP, Brown ME, Barlow M, Hoell A (2008) Warming of the Indian Ocean threatens eastern and southern African food security but could be mitigated by agricultural development. Proceedings of the National Academy of Sciences 105, 11 081–11 086

  • Funk C, Dettinger MD, Michaelsen JC, Verdin JP, Brown ME, Barlow M, Hoell A (2014) Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices. Hydrol Earth Syst Sci 18:4965–4978

    Article  Google Scholar 

  • Funk C, Hoell A (2015) The leading mode of observed and CMIP5 ENSO-residual sea surface temperatures and associated changes in Indo-Pacific climate. J Clim 28:4309–4329

    Article  Google Scholar 

  • Giannini A, Biasutti M, Held I, Sobel A (2008) A global perspective on African climate. Clim Change 90:359–383

    Article  Google Scholar 

  • Goddard L, Graham NE (1999) Importance of the Indian Ocean for simulating rainfall anomalies over eastern and southern Africa. Journal of Geophysical Research 104 (D16):19 099–19 116

  • Gregory D, Kershaw R, Inness PM (1997) Parametrization of momentum transport by convection. II: tests in single-column and general circulation models. Quart J R Meteorol Soci 123:1153–1183

    Article  Google Scholar 

  • Ham Y-G, Choi J-Y, Kug J-S (2016) The weakening of the ENSOIndian Ocean Dipole (IOD) coupling strength in recent decades. Climate Dynamics. doi:10.1007/s00382-016-3339-5

  • Hastenrath S (2007) Circulation mechanisms of climate anomalies in East Africa and the equatorial Indian Ocean. Dyn Atmos Oceans 43:25–35

    Article  Google Scholar 

  • Hastenrath S, Polzin D, Camberlin P (2004) Exploring the predictability of the ‘short rains’ at the coast of East Africa. Int J Climatol 24:1333–1343

    Article  Google Scholar 

  • Hastenrath S, Polzin D, Mutai C (2010) Diagnosing the droughts and floods in equatorial East Africa, during boreal autumn 2005–08. J Clim 23:813–817

    Article  Google Scholar 

  • Hastenrath S, Polzin D, Mutain C (2007) Diagnosing the 2005 drought in equatorial East Africa. J Clim 20:4628–4637

    Article  Google Scholar 

  • Hoell A, Funk C (2014) Indo-Pacific sea surface temperature influences on failed consecutive rainy seasons over eastern Africa. Clim Dyn 43:1645–1660

    Article  Google Scholar 

  • Hoell A, Hoerling M, Eischeid J, Quan W-X, Liebmann B (2017) Reconciling theories for human and natural attribution of recent East Africa drying. J Clim 30:1939–1957

    Article  Google Scholar 

  • Indeje M, Semazzi FHM, Ogallo LJ (2000) ENSO signals in East African rainfall seasons. Int J Climatol 20:19–46

    Article  Google Scholar 

  • Janowiak JE (1988) An investigation of interannual rainfall variability in Africa. J Clim 1:240–255

    Article  Google Scholar 

  • Jochum M (2009) Impact of latitudinal variations in vertical diffusivity on climate simulations. Journal of Geophysical Research 114(C01010): doi:10.1029/2008JC005 030

  • Jochum M, Potemra J (2008) Sensitivity of tropical rainfall to Banda Sea diffusivity in the community climate system model. J Clim 21:6445–6454

    Article  Google Scholar 

  • Kalnay E et al (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77:437–471

    Article  Google Scholar 

  • Kistler R et al (2001) The NCEP-NCAR 50-year reanalysis: monthly means CD-rom and documentation. Bull Am Meteorol Soc 82:247–267

    Article  Google Scholar 

  • Kosaka Y, Xie S-P (2013) Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature 501:403–407

    Article  Google Scholar 

  • Latif M, Dommenget D, Dima M, Grötzner A (1999) The role of Indian Ocean sea surface temperature in forcing East African rainfall anomalies during December-January 1997/98. J Clim 12:3497–3504

    Article  Google Scholar 

  • Liebmann B et al (2014) Understanding recent eastern Horn of Africa rainfall variability and change. J Clim 27:8630–8645

    Article  Google Scholar 

  • Liebmann B et al (2017) Climatology and interannual variability of boreal spring wet season precipitation in the eastern Horn of Africa and implications for its recent decline. J Clim 30:3867–3886

    Article  Google Scholar 

  • Lyon B (2014) Seasonal drought in the Greater Horn of Africa and its recent increase during the March–May long rains. J Clim 27:7953–7975

    Article  Google Scholar 

  • Lyon B, DeWitt DG (2012) A recent and abrupt decline in the East African long rains. Geophysical Research Letters 39(L02702): doi:10.1029/2011GL050 337

  • Manatsa D, Behera SK (2013) On the epochal strengthening in the relationship between rainfall of East Africa and IOD. J Clim 26:5655–5673

    Article  Google Scholar 

  • Manatsa D, Chipindu B, Behera SK (2012) Shifts in IOD and their impacts on association with East African rainfall. Theor Appl Climatol 110:115–128

    Article  Google Scholar 

  • Manatsa D, Morioka Y, Behera SK, Matarira CH, Yamagata T (2014) Impact of Mascarene High variability on the East African ‘short rains’. Clim Dyn 42:1259–1274

    Article  Google Scholar 

  • Manatsa D, Mudavanhu C, Mushore TD, Mavhura E (2016) Linking major shifts in the East Africa ‘short rains’ to the Southern Annular Mode. Int J Climatol 36:1590–1599

    Article  Google Scholar 

  • Monselesan DP, O’Kane TJ, Risbey JS, Church J (2015) Internal climate memory in observations and models. Geophys Res Lett 42:1232–1242

    Article  Google Scholar 

  • Mutai CC, Ward MN, Colman W (1998) Towards the prediction of East Africa short rains based on sea surface temperature-atmosphere coupling. Int J Climatol 18:975–997

    Article  Google Scholar 

  • Neale R, Richter J, Park S, Lauritzen P, Vavrus S, Rasch P, Zhang M (2013) The mean climate of the Community Atmosphere Model (CAM4) in forced sst and fully coupled experiments. J Clim 26:5150–5168

    Article  Google Scholar 

  • Neale RB et al (2012) Description of the NCAR Community Atmosphere Model (CAM 5.0). Tech. rep., NCAR Technical Note, NCAR/TN-486+STR, p 289

  • Nicholson SE (2014) A detailed look at the recent drought situation in the Greater Horn of Africa. J Arid Environ 103:71–79

    Article  Google Scholar 

  • Nicholson SE (2015) Long-term variability of the East African “short rains” and its links to large-scale factors. International Journal of Climatology. doi:10.1002/joc.4259

  • Nicholson SE (2016a) An analysis of recent rainfall conditions in eastern Africa. Int J Climatol 36:526–532

    Article  Google Scholar 

  • Nicholson SE (2016b) The Turkana low-level jet: mean climatology and association with regional aridity. Int J Climatol 36:2598–2614

    Article  Google Scholar 

  • Nicholson SE (2017) Climate and climatic variability of rainfall over Eastern Africa. Reviews of Geophysics. doi:10.1002/2016RG000544

  • Nicholson SE, Dezfuli AK, Klotter DA (2012) A two-century precipitation dataset for the continent of Africa. Bull Am Meteorol Soc 93:1219–1231

    Article  Google Scholar 

  • Ogallo LJ (1988) Relationships between seasonal rainfall in East Africa and the Southern Oscillation. J Climatol 8(1):31–43

    Article  Google Scholar 

  • Omondi PA et al (2014) Changes in temperature and precipitation extremes in the Greater Horn of Africa region from 1961 to 2010. Int J Climatol 34:1262–1277

    Article  Google Scholar 

  • Ongoma V, Chen H (2016) Temporal and spatial variability of temperature and precipitation over East Africa from 1951 to 2010. Meteorology and Atmosperic Physics. doi:10.1007/s00 703-016-0462-0

  • Parhi P, Giannini A, Gentine P, Lall U (2016) Resolving contrasting regional rainfall responses to El Niño over tropical Africa. J Clim 29:1461–1476

    Article  Google Scholar 

  • Rayner NA, Parker DE, Horton EB, Folland CK, Alexander LV, Rowell DP (2003) Global analyses of sst, sea ice and night marine air temperature since the late nineteenth century. Journal of Geophysical Research 108(4407): doi:10.1029/2002JD002 670

  • Reason CJC, Allan RJ, Lindesay JA, Ansell TJ (2000) Enso and climatic signals across the indian ocean basin in the global context: Part i, interannual composite patterns. Int J Climatol 20:1285–1327

    Article  Google Scholar 

  • Richter JH, Rasch PJ (2008) Effects of convective momentum transport on the atmospheric circulation in the Community Atmosphere Model, version 3. J Clim 21:1487–1499

    Article  Google Scholar 

  • Rowell DP, Booth BB, Nicholson SE, Good P (2015) Reconciling past and future rainfall trends over East Africa. J Clim 28:9768–9788

    Article  Google Scholar 

  • Saji NH, Goswami BN, Vinayachandran PN, Yamagata T (1999) A dipole mode in the tropical Indian Ocean. Nature 401:360–363

    Google Scholar 

  • Schneider U, Becker A, Finger P, Meyer-Christoffer A, Ziese M, Rudolf B (2013) GPCC’s new land surface precipitation climatology based on quality-controlled in situ data and its role in quantifying the global water cycle. Theoretical and Applied Climatology. doi:10.1007/s00 704-013-0860-x

  • Shongwe M, van Oldenborgh G, van den Hurk B, van Aalst M (2011) Projected changes in mean and extreme precipitation in Africa under global warming. Part II: East Africa. J Clim 24:3718–3733

    Article  Google Scholar 

  • Smith R et al (2010) The Parallel Ocean Program (POP) reference manual, ocean component of the Community Climate System Model (CCSM). Tech. rep., Los Alamos National Laboratory Tech. Rep. LAUR-10-01853, [Available online at http://www.cesm.ucar.edu/models/cesm1.0/pop2/doc/sci/ POPRefManual.pdf], p 141

  • Tierney JE, Smerdon JE, Anchukaitis KJ, Seager R (2013) Multidecadal variability in East African hydroclimate controlled by the Indian Ocean. Nature 493:389–392

    Article  Google Scholar 

  • Tierney JE, Ummenhofer CC, deMenocal PB (2015) Past and future rainfall in the Horn of Africa. Sci Adv 1(e1500):682

    Google Scholar 

  • Tozuka T, Luo J-J, Masson S, Yamagata T (2007) Decadal modulations of the Indian Ocean Dipole in the SINTEX-F1 coupled GCM. J Clim 20:2881–2894

    Article  Google Scholar 

  • Ummenhofer CC, England MH, Meyers GA, McIntosh PC, Pook MJ, Risbey JS, Sen Gupta A, Taschetto AS (2009a) What causes Southeast Australia’s worst droughts? Geophysical Research Letters 36(L04706): doi:10.1029/2008GL036 801

  • Ummenhofer CC, Sen Gupta A, England MH, Reason CJC (2009b) Contributions of Indian Ocean sea surface temperatures to enhanced East African rainfall. J Clim 22:993–1013

    Article  Google Scholar 

  • Ummenhofer CC et al (2011) Indian and Pacific Ocean influences on Southeast Australian drought and soil moisture. J Clim 24:1313–1336

    Article  Google Scholar 

  • Vigaud N, Lyon B, Giannini A (2017) Sub-seasonal teleconnections between convection over the Indian Ocean, the East African long rains and tropical Pacific surface temperatures. Int J Climatol 37:1167–1180

    Article  Google Scholar 

  • Vizy EK, Cook KH (2012) Mid-twenty-first-century changes in extreme events over northern and tropical Africa. J Clim 25:5748–5767

    Article  Google Scholar 

  • Vrieling A, Meroni M, Mude AG, Chantarat S, Ummenhofer CC, de Bie CAJM (2016) Early assessment of seasonal forage availability for mitigating the impact of drought on East African pastoralists. Rem Sens Environ 174:44–55

    Article  Google Scholar 

  • Webster PJ, Moore AM, Loschnigg JP, Leben RR (1999) Coupled ocean-atmosphere dynamics in the Indian Ocean during 1997–98. Nature 401:356–360

    Article  Google Scholar 

  • Williams AP, Funk C (2011) A westward extension of the warm pool leads to a westward extension of the Walker circulation, drying eastern Africa. Clim Dyn 37:2417–2435

    Article  Google Scholar 

  • Williams AP et al (2012) Recent summer precipitation trends in the Greater Horn of Africa and the emerging role of Indian Ocean sea surface temperature. Clim Dyn 39:2307–2328

    Article  Google Scholar 

  • Yang W, Seager R, Cane MA, Lyon B (2014) The East African long rains in observations and models. J Clim 27:7185–7202

    Article  Google Scholar 

  • Yang W, Seager R, Cane MA, Lyon B (2015) The annual cycle of East African precipitation. J Clim 28:2385–2404

    Article  Google Scholar 

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Acknowledgements

Use of the following data sets is gratefully acknowledged: Global Precipitation Climatology Center data set by the German Weather Service (DWD) through http://gpcc.dwd.de, NCEP/NCAR reanalysis data provided by NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, through http://www.cdc.noaa.gov; Hadley Centre HadISST by the UK Met Office, and the Twentieth Century Reanalysis Project supported by the U.S. DOE, Office of Science Innovative and Novel Computational Impact on Theory and Experiment program, Office of Biological and Environmental Research, and NOAA Climate Program Office. We also gratefully acknowledge use of CESM output and thank NCAR for producing and making available their model output. Comments by two anonymous reviewers are gratefully acknowledged as they helped improve an earlier version of the manuscript. The project was supported by the U.S. National Science Foundation under OCE-1203892, C.C.U. also through the Penzance and John P. Chase Memorial Endowed Funds, and the Investment in Science Fund at WHOI, and M.K. through the Research Internships in Science and Engineering (RISE) program by the German Foreign Exchange Service.

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Authors and Affiliations

  1. Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA, USA

    Caroline C. Ummenhofer

  2. Department of Earth Sciences, University of Hamburg, Hamburg, Germany

    Marco Kulüke

  3. Department of Geosciences, University of Arizona, Tucson, AZ, USA

    Jessica E. Tierney

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  1. Caroline C. Ummenhofer
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  2. Marco Kulüke
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  3. Jessica E. Tierney
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Correspondence to Caroline C. Ummenhofer.

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Ummenhofer, C.C., Kulüke, M. & Tierney, J.E. Extremes in East African hydroclimate and links to Indo-Pacific variability on interannual to decadal timescales. Clim Dyn 50, 2971–2991 (2018). https://doi.org/10.1007/s00382-017-3786-7

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