Seasonal Prediction of Summer Precipitation over East Africa Using NUIST-CFS1.0
Tóm tắt
East Africa is particularly vulnerable to precipitation variability, as the livelihood of much of the population depends on rainfed agriculture. Seasonal forecasts of the precipitation anomalies, when skillful, can therefore improve implementation of coping mechanisms with respect to food security and water management. This study assesses the performance of Nanjing University of Information Science and Technology Climate Forecast System version 1.0 (NUIST-CFS1.0) on forecasting June–September (JJAS) seasonal precipitation anomalies over East Africa. The skill in predicting the JJAS mean precipitation initiated from 1 May for the period of 1982–2019 is evaluated using both deterministic and probabilistic verification metrics on grid cell and over six distinct clusters. The results show that NUIST-CFS1.0 captures the spatial pattern of observed seasonal precipitation climatology, albeit with dry and wet biases in a few parts of the region. The model has positive skill across a majority of Ethiopia, Kenya, Uganda, and Tanzania, whereas it doesn’t exceed the skill of climatological forecasts in parts of Sudan and southeastern Ethiopia. Positive forecast skill is found over regions where the model shows better performance in reproducing teleconnections related to oceanic SST. The prediction performance of NUIST-CFS1.0 is found to be on a level that is potentially useful over a majority of East Africa.
Tài liệu tham khảo
Arribas, A., and Coauthors, 2011: The GloSea4 ensemble prediction system for seasonal forecasting. Mon. Wea. Rev., 139, 1891–1910, https://doi.org/10.1175/2010MWR3615.1.
Bahaga, T. K., A. H. Fink, and P. Knippertz, 2019: Revisiting inter-annual to decadal teleconnections influencing seasonal rainfall in the Greater Horn of Africa during the 20th century. International Journal of Climatology, 39, 2765–2785, https://doi.org/10.1002/joc.5986.
Behera, S. K., J. J. Luo, S. Masson, P. Delecluse, S. Gualdi, A. Navarra, and T. Yamagata, 2005: Paramount impact of the Indian Ocean Dipole on the East African short rains: A CGCM study. J. Climate, 18, 4514–4530, https://doi.org/10.1175/JCLI3541.1.
Beltrando, G., and P. Camberlin, 1993: Interannual variability of rainfall in the eastern horn of Africa and indicators of atmospheric circulation. International Journal of Climatology, 13, 533–546, https://doi.org/10.1002/joc.3370130505.
Camberlin, P., 1995: June-september rainfall in north-eastern Africa and atmospheric signals over the tropics: A zonal perspective. International Journal of Climatology, 15, 773–783, https://doi.org/10.1002/joc.3370150705.
Camberlin, P., 1997: Rainfall anomalies in the source region of the Nile and Their Connection with the Indian Summer Monsoon. J. Climate, 10, 1380–1392, https://doi.org/10.1175/1520-0442(1997)010<1380:RAITSR>2.0.CO;2.
Camberlin, P., and N. Philippon, 2001: The stationarity of lead-lag teleconnections with East Africa rainfall and its incidence on seasonal predictability. Detecting and Modelling Regional Climate Change, M. B. India and D. L. Bonillo, Eds., Springer, 291–307, https://doi.org/10.1007/978-3-662-04313-4_25.
Camberlin, P., S. Janicot, and I. Poccard, 2001: Seasonality and atmospheric dynamics of the teleconnection between African rainfall and tropical sea-surface temperature: Atlantic vs. ENSO. International Journal of Climatology, 21, 973–1005, https://doi.org/10.1002/joc.673.
Dawson, A., and T. N. Palmer, 2015: Simulating weather regimes: Impact of model resolution and stochastic parameterization. Climate Dyn., 44, 2177–2193, https://doi.org/10.1007/s00382-014-2238-x.
Dawson, A., T. N. Palmer, and S. Corti, 2012: Simulating regime structures in weather and climate prediction models. Geophys. Res. Lett., 39, L21805, https://doi.org/10.1029/2012GL053284.
Dinku, T., C. Funk, P. Peterson, R. Maidment, T. Tadesse, H. Gadain, and P. Ceccato, 2018: Validation of the CHIRPS satellite rainfall estimates over eastern Africa. Quart. J. Roy. Meteor. Soc., 144, 292–312, https://doi.org/10.1002/qj.3244.
Diro, G. T., D. I. F. Grimes, and E. Black, 2011a: Teleconnections between Ethiopian summer rainfall and sea surface temperature: Part I-observation and modelling. Climate Dyn., 37, 103–119, https://doi.org/10.1007/s00382-010-0837-8.
Diro, G. T., D. I. F. Grimes, and E. Black, 2011b: Large scale features affecting ethiopian rainfall. African Climate and Climate Change: Physical, Social and Political Perspectives, C. J. R. Williams and D. R. Kniveton, Eds., Springer, 13–50, https://doi.org/10.1007/978-90-481-3842-5_2.
Diro, G. T., D. I. F. Grimes, and E. Black, 2011c: Teleconnections between Ethiopian summer rainfall and sea surface temperature: Part II. Seasonal forecasting. Climate Dyn., 37, 121–131, https://doi.org/10.1007/s00382-010-0896-x.
Doblas-Reyes, F. J., J. García-Serrano, F. Lienert, A. P. Biescas, and L. R. L. Rodrigues, 2013: Seasonal climate predictability and forecasting: Status and prospects. WIREs Climate Change, 4, 245–268, https://doi.org/10.1002/wcc.217.
Endris, H. S., C. Lennard, B. Hewitson, A. Dosio, G. Nikulin, and G. A. Artan, 2019: Future changes in rainfall associated with ENSO, IOD and changes in the mean state over Eastern Africa. Climate Dyn., 52, 2029–2053, https://doi.org/10.1007/s00382-018-4239-7.
FEWS NET, 2011: East Africa: Past Year One of the Driest on Record in the Eastern Horn. Famine Early Warning System Network Rep. Available from https://reliefweb.int/sites/reliefweb.int/files/resources/FEWS%2520NET%2520EA_Historical%2520drought%2520context_061411.pdf.
Funk, C., and Coauthors, 2015a: The climate hazards infrared precipitation with stations — A new environmental record for monitoring extremes. Scientific Data, 2, 150066, https://doi.org/10.1038/sdata.2015.66.
Funk, C., A. Verdin, J. Michaelsen, P. Peterson, D. Pedreros, and G. Husak, 2015b: A global satellite-assisted precipitation climatology. Earth System Science Data, 7, 275–287, https://doi.org/10.5194/essd-7-275-2015.
Gissila, T., E. Black, D. I. F. Grimes, and J. M. Slingo, 2004: Seasonal forecasting of the Ethiopian summer rains. International Journal of Climatology, 24, 1345–1358, https://doi.org/10.1002/joc.1078.
Goddard, L., A. G. Barnston, and S. J. Mason, 2003: Evaluation of the IRI’s “net assessment” seasonal climate forecasts: 1997–2001. Bull. Amer. Meteor. Soc., 84, 1761–1781, https://doi.org/10.1175/BAMS-84-12-1761.
Graham, R., A. Colman, M. Vellinga, and E. Wallace, 2012: Use of dynamical seasonal forecasts in the consensus outlooks of African Regional Climate Outlook Forums (RCOFs). ECMWF Annual Seminar 2012, ECMWF, 3–7.
Gubler, S., and Coauthors, 2020: Assessment of ECMWF SEAS5 seasonal forecast performance over South America. Wea. Forecasting, 35, 561–584, https://doi.org/10.1175/WAF-D-19-0106.1.
He, J. Y., J. Y. Wu, and J. J. Luo, 2020: Introduction to climate forecast system version 1.0 of Nanjing University of Information Science and Technology. Transactions of Atmospheric Sciences, 43(1), 128–143, https://doi.org/10.13878/j.cnki.dqkxxb.20191110007. (in Chinese with English abstract)
Hersbach, H., and Coauthors, 2020: The ERA5 global reanalysis. Quart. J. Roy. Meteor. Soc., 146, 1999–2049, https://doi.org/10.1002/qj.3803.
Huang, B. Y., and Coauthors, 2017: Extended reconstructed Sea surface temperature, Version 5 (ERSSTv5): Upgrades, validations, and intercomparisons. J. Climate, 30, 8179–8205, https://doi.org/10.1175/JCLI-D-16-0836.1.
Indeje, M., F. H. M. Semazzi, and L. J. Ogallo, 2000: ENSO signals in East African rainfall seasons. International Journal of Climatology, 20, 19–46, https://doi.org/10.1002/(SICI)1097-0088(200001)20:1<19::AID-JOC449>3.0.CO;2-0.
Kew, S. F., and Coauthors, 2021: Impact of precipitation and increasing temperatures on drought trends in eastern Africa. Earth System Dynamics, 12, 17–35, https://doi.org/10.5194/esd-12-17-2021.
Kim, G., J. B. Ahn, V. N. Kryjov, W. S. Lee, D. J. Kim, and A. Kumar, 2021: Assessment of MME methods for seasonal prediction using WMO LC-LRFMME hindcast dataset. International Journal of Climatology, 41, E2462–E2481, https://doi.org/10.1002/joc.6858.
Korecha, D., and A. G. Barnston, 2007: Predictability of June–September rainfall in ethiopia. Mon. Wea. Rev., 135, 628–650, https://doi.org/10.1175/MWR3304.1.
Kucharski, F., A. Bracco, J. H. Yoo, A. M. Tompkins, L. Feudale, P. Ruti, and A. Dell’Aquila, 2009: A Gill-Matsuno-type mechanism explains the tropical Atlantic influence on African and Indian monsoon rainfall. Quart. J. Roy. Meteor. Soc., 135, 569–579, https://doi.org/10.1002/qj.406.
Luo, J.-J., S. Masson, S. Behera, P. Delecluse, S. Gualdi, A. Navarra, and T. Yamagata, 2003: South Pacific origin of the decadal ENSO-line variation as simulated by a coupled GCM. Geophys. Res. Lett., 30, 2250, https://doi.org/10.1029/2003GL018649.
Luo, J.-J., S. Masson, E. Roeckner, G. Madec, and T. Yamagata, 2005a: Reducing climatology bias in an Ocean—Atmosphere CGCM with improved coupling physics. J. Climate, 18, 2344–2360, https://doi.org/10.1175/JCLI3404.1.
Luo, J.-J., S. Masson, S. Behera, S. Shingu, and T. Yamagata, 2005b: Seasonal climate predictability in a coupled OAGCM using a different approach for ensemble forecasts. J. Climate, 18, 4474–4497, https://doi.org/10.1175/JCLI3526.1.
Luo, J.-J., S. Masson, S. Behera, and T. Yamagata, 2007: Experimental forecasts of the Indian Ocean dipole using a coupled OAGCM. J. Climate, 20, 2178–2190, https://doi.org/10.1175/JCLI4132.1.
Luo, J.-J., S. Behera, Y. Masumoto, H. Sakuma, and T. Yamagata, 2008a: Successful prediction of the consecutive IOD in 2006 and 2007. Geophys. Res. Lett., 35, L14S02, https://doi.org/10.1029/2007GL032793.
Luo, J.-J., S. Masson, S. K. Behera, and T. Yamagata, 2008b: Extended ENSO predictions using a fully coupled ocean-atmosphere model. J. Climate, 21, 84–93, https://doi.org/10.1175/2007JCLI1412.1.
MacLachlan, C., and Coauthors, 2015: Global Seasonal forecast system version 5 (GloSea5): A high-resolution seasonal forecast system. Quart. J. Roy. Meteor. Soc., 141, 1072–1084, https://doi.org/10.1002/qj.2396.
MacLeod, D., 2018: Seasonal predictability of onset and cessation of the east African rains. Weather and Climate Extremes, 21, 27–35, https://doi.org/10.1016/j.wace.2018.05.003.
Madec, G., P. Delécluse, M. Imbard, and C. Lévy, 1998: OPA 8.1 Ocean General Circulation Model Reference Manual. Notes du Pôle Modélisation, Institut Pierre Simon Laplace. Available from https://hal.archives-ouvertes.fr/hal-00154217.
Mason, I., 1982: A model for assessment of weather forecasts. Aust. Meteor. Mag., 30, 291–303.
Mason, S. J., and S. Chidzambwa, 2008: Verification of African RCOF forecasts. IRI Technical Report, 09–02, 26 pp.
Mason, S. J., and A. P. Weigel, 2009: A generic forecast verification framework for administrative purposes. Mon. Wea. Rev., 137, 331–349, https://doi.org/10.1175/2008MWR2553.1.
Mason, S. J., M. K. Tippett, L. L. Song, and Á. G. Muñoz, 2019: Climate Predictability Tool Version 16.1.5. Columbia University Academic Commons. Available from https://doi.org/10.7916/d8-qswz-nj26.
Mishra, N., C. Prodhomme, and V. Guemas, 2019: Multi-model skill assessment of seasonal temperature and precipitation forecasts over Europe. Climate Dyn., 52, 4207–4225, https://doi.org/10.1007/s00382-018-4404-z.
Mutai, C. C., and M. N. Ward, 2000: East African rainfall and the tropical circulation/convection on intraseasonal to interannual timescales. J. Climate, 13, 3915–3939, https://doi.org/10.1175/1520-0442(2000)013<3915:EARATT>2.0.CO;2.
Mwangi, E., F. Wetterhall, E. Dutra, F. Di Giuseppe, and F. Pappenberger, 2014: Forecasting droughts in East Africa. Hydrology and Earth System Sciences, 18, 611–620, https://doi.org/10.5194/hess-18-611-2014.
Nicholson, S. E., 2014: The predictability of rainfall over the greater horn of Africa. Part I: Prediction of seasonal rainfall. J. Hydrometeorol., 15, 1011–1027, https://doi.org/10.1175/JHM-D-13-062.1.
Nicholson, S. E., 2017: Climate and climatic variability of rainfall over eastern Africa. Rev. Geophys., 55, 590–635, https://doi.org/10.1002/2016RG000544.
Ogallo, L. J., 1989: The spatial and temporal patterns of the East African seasonal rainfall derived from principal component analysis. International Journal of Climatology, 9, 145–167, https://doi.org/10.1002/joc.3370090204.
Ogallo, L. J., J. E. Janowiak, and M. S. Halpert, 1988: Teleconnection between seasonal rainfall over East Africa and global sea surface temperature anomalies. J. Meteor. Soc. Japan, 66, 807–822, https://doi.org/10.2151/jmsj1965.66.6_807.
Ogutu, G. E. O., W. H. P. Franssen, I. Supit, P. Omondi, and R. W. A. Hutjes, 2017: Skill of ECMWF system-4 ensemble seasonal climate forecasts for East Africa. International Journal of Climatology, 37, 2734–2756, https://doi.org/10.1002/joc.4876.
Palmer, T. N., and Coauthors, 2004: Development of a European multimodel ensemble system for seasonal-to-interannual prediction (DEMETER). Bull. Amer. Meteor. Soc., 85, 853–872, https://doi.org/10.1175/BAMS-85-6-853.
Philip, S., and Coauthors 2018: Attribution analysis of the Ethiopian drought of 2015. J. Climate, 31, 2465–2486, https://doi.org/10.1175/JCLI-D-17-0274.1.
Preethi, B., T. P. Sabin, J. A. Adedoyin, and K. Ashok, 2015: Impacts of the ENSO Modoki and other tropical indo-pacific climate-drivers on African rainfall. Scientific Reports, 5, 16653, https://doi.org/10.1038/srep16653.
Pricope, N. G., G. Husak, D. Lopez-Carr, C. Funk, and J. Michaelsen, 2013: The climate-population nexus in the East African Horn: Emerging degradation trends in rangeland and pastoral livelihood zones. Global Environmental Change, 23, 1525–1541, https://doi.org/10.1016/j.gloenvcha.2013.10.002.
Riddle, E. E., and K. H. Cook, 2008: Abrupt rainfall transitions over the Greater Horn of Africa: Observations and regional model simulations. J. Geophys. Res., 113, D15109, https://doi.org/10.1029/2007JD009202.
Roeckner, E., and Coauthors, 2003: The atmospheric general circulation model ECHAM 5. PART I: Model description. MPI-Report 349, 127 pp.
Saji, N. H., B. N. Goswami, P. N. Vinayachandran, and T. Yamagata, 1999: A dipole mode in the tropical Indian ocean. Nature, 401, 360–363, https://doi.org/10.1038/43854.
Segele, Z. T., and P. J. Lamb, 2005: Characterization and variability of Kiremt rainy season over Ethiopia. Meteorol. Atmos. Phys., 89, 153–180, https://doi.org/10.1007/s00703-005-0127-x.
Segele, Z. T., P. J. Lamb, and L. M. Leslie, 2009a: Seasonal-to-interannual variability of Ethiopia/horn of Africa monsoon. Part I: Associations of wavelet-filtered large-scale atmospheric circulation and global sea surface temperature. J. Climate, 22, 3396–3421, https://doi.org/10.1175/2008JCLI2859.1.
Segele, Z. T., P. J. Lamb, and L. M. Leslie, 2009b: Large-scale atmospheric circulation and global sea surface temperature associations with Horn of Africa June–September rainfall. International Journal of Climatology, 29, 1075–1100, https://doi.org/10.1002/joc.1751.
Seregina, L. S., A. H. Fink, R. van der Linden, N. A. Elagib, and J. G. Pinto, 2019: A new and flexible rainy season definition: Validation for the Greater Horn of Africa and application to rainfall trends. International Journal of Climatology, 39, 989–1012, https://doi.org/10.1002/joc.5856.
Seregina, L. S., A. H. Fink, R. van der Linden, C. Funk, and J. G. Pinto, 2021: Using seasonal rainfall clusters to explain the interannual variability of the rain belt over the Greater Horn of Africa. International Journal of Climatology, 41, E1717–E1737, https://doi.org/10.1002/joc.6802.
Sheskin, D. J., 2011: Handbook of Parametric and Nonparametric Statistical Procedures. 5th ed. CRC Press, 1926 pp.
Shukla, S., J. Roberts, A. Hoell, C. C. Funk, F. Robertson, and B. Kirtman, 2019: Assessing North American multimodel ensemble (NMME) seasonal forecast skill to assist in the early warning of anomalous hydrometeorological events over East Africa. Climate Dyn., 53, 7411–7427, https://doi.org/10.1007/s00382-016-3296-z.
Straus, D. M., S. Corti, and F. Molteni, 2007: Circulation regimes: Chaotic variability versus SST-forced predictability. J. Climate, 20, 2251–2272, https://doi.org/10.1175/JCLI4070.1.
Sun, L. Q., F. H. M. Semazzi, F. Giorgi, and L. Ogallo, 1999a: Application of the NCAR regional climate model to eastern Africa: 1. Simulation of the short rains of 1988. J. Geophys. Res., 104, 6529–6548, https://doi.org/10.1029/1998JD200051.
Sun, L. Q., F. H. M. Semazzi, F. Giorgi, and L. Ogallo, 1999b: Application of the NCAR regional climate model to eastern Africa: 2. Simulation of interannual variability of short rains. J. Geophys. Res., 104, 6549–6562, https://doi.org/10.1029/1998JD200050.
Timm, N. H., and J. E. Carlson, 1976: Part and bipartial canonical correlation analysis. Psychometrika, 41, 159–176, https://doi.org/10.1007/BF02291836.
Trenberth, K. E., 1997: The definition of El Niño. Bull. Amer. Meteor. Soc., 78, 2771–2778, https://doi.org/10.1175/1520-0477(1997)078<2771:TDOENO>2.0.CO;2.
Tsidu, G. M., 2012: High-resolution monthly rainfall database for Ethiopia: Homogenization, reconstruction, and gridding. J. Climate, 25, 8422–8443, https://doi.org/10.1175/JCLI-D-12-00027.1.
Viste, E., and A. Sorteberg, 2013a: Moisture transport into the Ethiopian highlands. International Journal of Climatology, 33, 249–263, https://doi.org/10.1002/joc.3409.
Viste, E., and A. Sorteberg, 2013b: The effect of moisture transport variability on Ethiopian summer precipitation. International Journal of Climatology, 33, 3106–3123, https://doi.org/10.1002/joc.3566.
Viste, E., D. Korecha, and A. Sorteberg, 2013: Recent drought and precipitation tendencies in Ethiopia. Theor. Appl. Climatol., 112, 535–551, https://doi.org/10.1007/s00704-012-0746-3.
Vizy, E. K., and K. H. Cook, 2001: Mechanisms by which Gulf of Guinea and eastern North Atlantic sea surface temperature anomalies can influence African rainfall. J. Climate, 14, 795–821, https://doi.org/10.1175/1520-0442(2001)014<0795:MBWGOG>2.0.CO;2.
Vizy, E. K., and K. H. Cook, 2003: Connections between the summer east African and Indian rainfall regimes. J. Geophys. Res., 108, 4510, https://doi.org/10.1029/2003jd003452.
Walker, D. P., C. E. Birch, J. H. Marsham, A. A. Scaife, R. J. Graham, and Z. T. Segele, 2019: Skill of dynamical and GHACOF consensus seasonal forecasts of East African rainfall. Climate Dyn., 53, 4911–4935, https://doi.org/10.1007/s00382-019-04835-9.
Weigel, A. P., 2012: Ensemble forecasts. Forecast Verification: A Practitioner’s Guide in Atmospheric Science, 2nd ed. T. Jolliffe and David B. Stephenson, Eds., John Wiley & Sons, 141–166, https://doi.org/10.1002/9781119960003.ch8.
Weigel, A. P., and S. J. Mason, 2011: The generalized discrimination score for ensemble forecasts. Mon. Wea. Rev., 139, 3069–3074, https://doi.org/10.1175/MWR-D-10-05069.1.
Weigel, A. P., M. A. Liniger, and C. Appenzeller, 2007: Generalization of the discrete brier and ranked probability skill scores for weighted multimodel ensemble forecasts. Mon. Wea. Rev., 135, 2778–2785, https://doi.org/10.1175/MWR3428.1.
Wilks, D. S., 2011: Statistical Methods in the Atmospheric Sciences. 3rd ed. Elsevier, 818 pp.
Williams, A. P., and Coauthors, 2012: Recent summer precipitation trends in the Greater Horn of Africa and the emerging role of Indian Ocean sea surface temperature. Climate Dyn., 39, 2307–2328, https://doi.org/10.1007/s00382-011-1222-y.
Yamagata, T., S. K. Behera, J. J. Luo, S. Masson, M. R. Jury, and S. A. Rao, 2004: Coupled ocean-atmosphere variability in the tropical Indian ocean. Earth’s Climate: The Ocean-Atmosphere Interaction, Volume 147, C. Wang, et al., Eds., American Geophysical Union, 189–211, https://doi.org/10.1029/147GM12.
Yang, Y. H., B. T. Qian, Q. C. Xu, and Y. Yang, 2020: Climate regionalization of asphalt pavement based on the K-means clustering algorithm. Advances in Civil Engineering, 2020, 6917243, https://doi.org/10.1155/2020/6917243.
Young, H. R., and N. P. Klingaman, 2020: Skill of seasonal rainfall and temperature forecasts for East Africa. Wea. Forecasting, 35, 1783–1800, https://doi.org/10.1175/WAF-D-19-0061.1.
Yule, G. U., 1907: On the theory of correlation for any number of variables, treated by a new system of notation. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 79, 182–193.
Ziervogel, G., M. Bithell, R. Washington, and T. Downing, 2005: Agent-based social simulation: A method for assessing the impact of seasonal climate forecast applications among smallholder farmers. Agricultural Systems, 83, 1–26, https://doi.org/10.1016/j.agsy.2004.02.009.