Improving multimodel medium range forecasts over the Greater Horn of Africa using the FSU superensemble
- 156 Downloads
This study makes use of the WMO’s multimodel data set called THORPEX integrated grand global ensemble (TIGGE) towards the construction of multimodel superensemble forecasts covering a period of 10 days. The goal of this study is to explore the forecast skill for precipitation forecasts over the Greater Horn of Africa (this is a consortium of 11 countries). The multimodels include forecast data set from a suite of models that include: The European Centre for Medium Range Weather Forecasts (ECMWF), the National Centre for Environmental Prediction (NCEP), the Center for Weather Forecast and Climatic Studies (CPTEC) and the United Kingdom Meteorological Office (UKMO). After performing a training phase for the superensemble weights covering the previous 450 days of October, November and December months of 2008–2012, forecasts of precipitation were prepared for the multimodel superensemble. These covered day 1 to day 10 of forecasts over the region. Various skill metrics were prepared to validate the forecast rainfall against the tropical rainfall measuring mission (TRMM) observed rainfall data. This study shows that the construction of the multimodel superensemble was a worthwhile effort since it provided the best overall skills for the RMS errors, the spatial correlations and the equitable threat scores and their bias errors for precipitation forecasts from day 1 to day 10 over all of the countries covered by the Greater Horn of Africa. The best among the member model was the UKMO model. This study strongly suggests the usefulness of a product such as the multimodel superensemble for improved precipitation forecasts over East Africa.
KeywordsIndian Ocean Dipole Tropical Rainfall Monitoring Mission Forecast Skill Precipitation Forecast Bias Score
This work was supported by NSF Grant No. UFSU0004. This research study was also supported by IGAD Climate Prediction and Applications Centre (ICPAC) for the support of the principal author while he was visiting Florida State University. We wish to acknowledge the THORPEX Integrated Grand Global Ensemble (TIGGE) for providing the forecast data used in this paper.
- Bhardwaj A, Krishnamurti TN, Sharma OP, Mishra AK, Singh T (2015) Monsoon precipitation forecast using a suite of mesoscale models. (under peer review by meteorological applications) Google Scholar
- Downie C, Wilkinson P (1972) The geology of Kilimanjaro. University of Sheffield, Earth Sciences, SheffieldGoogle Scholar
- Hou A, Jackson GS, Kummerow C, Shepherd C (2008) Global precipitation measurement. In: Silas M (ed) Precipitation: advances in measurement, estimation, and prediction. Springer, Berlin, pp 1–39Google Scholar
- Kibara DG (2011) Predictability of weather on extended NWP timescales over Kenya using the NCEP GFS model. Msc. Thesis, Dept. of Meteorology, University of NairobiGoogle Scholar
- Krishnamurti TN, Surendran S, Shin DW, Correa-Torres RJ, Kumar TS, Williford CE, Kummerow C, Adler RF, Simpson J, Kakar R, Olson WS, Turk FJ (2001) Real time multi-analysis/multi-model superensemble forecasts of precipitation using TRMM and SSM/I products. Mon Wea Rev 129:2861–2883CrossRefGoogle Scholar
- Kumar K, Rajagopalan B, Cane M (1999) On the weakening relationship between the Indian Monsoon and ENSO. Science 284(2): 2156–2159; American Association for the Advancement of Science; Washington DCGoogle Scholar
- Mitra AK, Iyengar GR, Durai VR, Sanjay J, Krishnamurti TN, Mishra A, and Sikka DR (2011) Experimental real-time multi-model ensemble (MME) prediction of rainfall during monsoon 2008: large-scale medium-range aspects. J Earth Syst Sci. Springer, 120(1): 27–52Google Scholar
- Richardson DR, Buizza and Hagedorn R (2005) Final report of the 1st workshop on the THORPEX interactive grand global ensemble (TIGGE). WMO TD No. 1273, WWRP-THORPEX No. 5 pdfGoogle Scholar
- Saji NH, Goswami BN, Vinayachandran PN, Yamagata T (1999) A dipole in the tropical Indian Ocean. Nature 401:360–363Google Scholar
- Sakwa VN (2006) Assessment of the skill of the high resolution regional model in the simulation of airflow and rainfall over East Africa. Msc. Thesis, Dept. of Meteorology, University of NairobiGoogle Scholar
- Zhu Y, Toth Z, Rutledge GK (2008) TIGGE and NAEFS: Research and operational developments in multi-center ensemble forecasting. American Geophysical Union, Spring Meeting 2008, abstract #IN41A-03Google Scholar