Background

Mason has been involved in seasonal climate forecasting research and operations since the early 1990s. He has published numerous papers on seasonal climate forecasting and verification, climate change, and southern African climate variability. He has extensive experience in the production of seasonal climate forecasts in contexts such as the Regional Climate Outlook Forums, and works closely with the World Meteorological Organization (WMO) to promote the definition and adoption of forecasting and verification standards through engagement in the relevant WMO Expert Teams and through the WMO CLIPS Capacity Building Workshops. Mason joined the IRI in 1997, working initially at the Scripps Insitution of Oceanography, and moving to Columbia University in 2003. Prior to joining the IRI, Mason was Deputy Director of the Climatology Research Group at the University of the Witwatersrand, in South Africa, where he developed empirical models for predicting southern African rainfall variability. Mason is a Visiting Senior Fellow in the Centre for Analysis of Time Series at the London School of Economics and Political Science.

Research Interests

Mason's primary areas of research include development of methods for diagnosing the quality of forecasts ("forecast verification"), and for recalibrating ensemble predictions. As part of the IRI's outreach and collaboration with other partners, Mason has been heavily involved in capacity building activities, including leading the development and support of the Climate Predictability Tool (CPT).

Role

Mason is leader of the IRI's Climate Program.

Published Papers and Books

2009

Lyon, B., and S. J. Mason, 2009: The 1997-98 summer rainfall season in southern Africa. Part II: model simulations and coupled model forecasts. Journal of Climate, 22, 3802-3818.

Mason, S. J., and A. P. Weigel, 2009: A generic forecast verification framework for administrative purposes. Monthly Weather Review, 137, 331-349.

2008

Abawi, Y., P. Llanso, M. S. J. Harrison, and S. J. Mason, 2008: Water, health and early warnings. In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 351-395.

B. Casati, L. J. Wilson, D. B. Stephenson, P. Nurmi, A. Ghelli, M. Pocernich, U. Damrath, E. E. Ebert, B. G. Brown, and S. J. Mason, 2008: Forecast verification: current status and future directions. Meteorological Applications, 15, 3-18.

Harrison, M. S. J., A. Troccoli, D. L. T. Anderson, and S. J. Mason, 2008: Introduction. In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 3-11.

Harrison, M. S. J., A. Troccoli, D. L. T. Anderson, S. J. Mason, M. Coughlan, and J. Williams, 2008: A way forward for seasonal climate services. In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 399-410.

Mason, S. J., 2008: Understanding forecast verification statistics. Meteorological Applications, 15, 31-40.

Mason, S. J., 2008: "Flowering walnuts in the wood" and other bases for seasonal climate forecasting. In Thomson, M. C., and R. G. Herrera (Eds), Climatic Change, Seasonal Forecasts and Human Health, Advances in Global Change Research (AGLO), Springer, Dordrecht, 13-29.

Mason, S. J., 2008: From dynamical predictions to seasonal forecasts. In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 205-234.

Mason, S. J., and O. Baddour, 2008: Statistical modeling. In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 163-201.

Mason, S. J., and D. B. Stephenson, 2008: How can we know whether the forecasts are any good? In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 259-289.

Tippett, M. K., T. DelSole, S. J. Mason, and A. G. Barnston, 2008: Regression-based methods for finding coupled patterns. Journal of Climate, 21, 4384-4398.

Troccoli, A., M. S. J. Harrison, S. J. Mason, and D. L. T. Anderson, 2008: Glossary of terms. In Troccoli, A., M. S. J. Harrison, D. L. T. Anderson, and S. J. Mason (Eds), Seasonal Climate Variability: Forecasting and Managing Risk, Springer Academic Publishers, Dordrecht, 417-434.

2007

Da Silva, J., S. J. Connor, S. J. Mason, and M. C. Thomson, 2007: Response to Cox and Abeku: Early warning systems for malaria in Africa: from blueprint to practice. Trends in Parasitology, 23, 246-247.

Lyon, B., and S. J. Mason, 2007: The 1997-98 summer rainfall season in southern Africa. Part I: observations. Journal of Climate, 20, 5134-5148.

Mason, S. J., J. S. Galpin, L. Goddard, N. E. Graham, and B. Rajaratnam, 2007: Conditional exceedance probabilities. Monthly Weather Review, 135, 363-372.

2006

Shongwe, M. E., W. A. Landman, and S. J. Mason, 2006: Performance of recalibration systems of GCM forecasts for Southern Africa. International Journal of Climatology, 26, 1567-1585.

Thomson, M. C., F. J. Doblas-Reyes, S. J. Mason, R. Hagedorn, S. J. Connor, T. Phindela, A. P. Morse, and T. N. Palmer, 2006: Multi-model ensemble seasonal climate forecasts for malaria early warning. Nature, 439, 576-579.

2005

Graham, N. E., and S. J. Mason, 2005: A method for ensemble expansion and improved definition of forecast distributions from cliamte simulations. Quarterly Journal of the Royal Meteorological Society, 131, 939-963.

Thomson, M. C., S. J. Mason, T. Phindela, and S. J. Connor, 2005: Use of rainfall and sea surface temperature monitoring for malaria early warning in Botswana. American Journal of Tropical Medicine and Hygiene, 73, 214-221.

2004

Da Silva, J., B. Garanganga, V. Teveredzi, S. M. Marx, S. J. Mason, and S. J. Connor, 2004: Improving epidemic malaria planning, preparedness and response in Southern Africa. Malaria Journal, 3, 37.

Mason, S. J., 2004: On using "climatology" as a reference strategy in the Brier and ranked probability skill scores. Monthly Weather Review, 137, 1891-1895.

Mason, S. J., 2004: Simulating climate over western North America using stochastic weather generators. Climatic Change, 62, 155-187.

2003

Goddard, L., A. G. Barnston, and S. J. Mason, 2003: Evaluation of the IRI's "Net Assessment" seasonal climate forecasts, 1997-2001. Bulletin of the American Meteorological Society, 84, 1761-1781.

Barnston, A. G., S. J. Mason, L. Goddard, L., D. G. DeWitt, and S. E. Zebiak, 2003: Multi-model ensembling in seasonal climate forecasting at IRI. Bulletin of the American Meteorological Society, 84, 1783-1796.

2002

Goddard, L., and S. J. Mason, 2002: Sensitivity of seasonal climate forecasts to persisted SST anomalies. Climate Dynamics, 19, 619-632.

Mason, S. J., and N. E. Graham, 2002: Areas beneath the relative operating characteristics (ROC) and levels (ROL) curves: statistical significance and interpretation. Quarterly Journal of the Royal Meteorological Society, 128, 2145-2166.

Mason, S. J., and G. M. Mimmack, 2002: Comparison of some statistical methods of probabilistic forecasting of ENSO. Journal of Climate, 15, 8-29.

Unganai, L. S., and S. J. Mason, 2002: Long-range predictability of Zimbabwe summer rainfall. International Journal of Climatology, 22, 1091-1103.

2001

Goddard, L., S. J. Mason, S. E. Zebiak, C. F. Ropelewski, R. Basher, and M. A. Cane, 2001: Current approaches to seasonal to interannual climate predictions. International Journal of Climatology, 21, 1111-1152.

Landman, W. A., and S. J. Mason, 2001: Forecasts of near-global sea-surface temperatures using canonical correlation analysis. Journal of Climate, 14, 3819-3833.

Landman, W. A., S. J. Mason, and W. J. Tennant, 2001: Statistical downscaling of GCM simulations to streamflow. Journal of Hydrology, 252, 221-236.

Landman, W. A., S. J. Mason, P. D. Tyson, and W. J. Tennant, 2001: Retro-active skill of multi-tiered forecasts of summer rainfall over southern Africa. International Journal of Climatology, 21, 1-19.

Mason, S. J., 2001: El Nino, climate change, and southern African climate. Environmetrics, 12, 327-345.

Mason, S. J., and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bulletin of the American Meteorological Society, 82, 619-638.

Mimmack, G. M., S. J. Mason, and J. S. Galpin, 2001: Choice of distance matrices in cluster analysis: defining regions. Journal of Climate, 14, 2790-2797.

Unganai, L. S., and S. J. Mason, 2001: Spatial characterisation of Zimbabwe summer rainfall during the period 1920-1996. South African Journal of Science, 97, 425-431.

2000

Mason, S. J., and P. D. Tyson, 2000: The occurrence and predictability of droughts over southern Africa. In D. A. Wilhite (Ed.), Drought. Volume 1: A Global Assessment. Routledge, New York, 113-134.

1999

Crimp, S. J., and S. J. Mason, 1999: The extreme precipitation event of 11 to 16 February 1996 over South Africa. Meteorology and Atmospheric Physics, 70, 29-42.

Jury, M. R., H. M. Mulenga, and S. J. Mason, 1999: Explanatory long-range models to estimate summer climate variability over southern Africa. Journal of Climate, 12, 1892-1899.

Landman, W. A., and S. J. Mason, 1999: Operational long-lead prediction of South African rainfall using canonical correlation analysis. International Journal of Climatology, 19, 1073-1090.

Landman, W. A., and S. J. Mason, 1999: Changes in the association between Indian Ocean sea-surface temperatures and South African summer rainfall. International Journal of Climatology, 19, 1477-1492.

Mason, S. J., and N. E. Graham, 1999: Conditional probabilities, relative operating characteristics, and relative operating levels. Weather and Forecasting, 14, 713-725.

Mason, S. J., P. R. Waylen, G. M. Mimmack, B. Rajaratnam, and J. M. Harrison, 1999: Changes in extreme rainfall events in South Africa. Climatic Change, 41, 249-257.

Mason, S. J., L. Goddard, N. E. Graham, E. Yulaeva, L. Sun, and P. A. Arkin, 1999: The IRI seasonal climate prediction system and the 1997/98 El Nino event. Bulletin of the American Meteorological Society, 80, 1853-1873.

Ogallo, L., S. J. Mason, S. M. King'uyu, S. E. Nicholson, B. S. Nyenzi, E. Matari, and G. M. Mimmack, 1999: Indices and indicators of climate extremes in Africa. Journal of the African Meteorological Society, 4, 17-29.

1998

Crimp, S. J., J. R. E. Lutjeharms, and S. J. Mason, 1998: The sensitivity of a tropical-temperate trough to sea-surface temperatures in the Agulhas retroflection region. Water SA, 24, 93-100.

Mason, S. J., 1998: Seasonal forecasting of South African rainfall using a non-linear discriminant analysis model. International Journal of Climatology, 18, 147-164.

Mattes, M., and S. J. Mason, 1998: Evaluation of a seasonal forecasting procedure for Namibian rainfall. South African Journal of Science, 94, 183-185.

Tyson, P.D., S. J. Mason, M. Q. W. Jones, and G. R. J. Cooper, 1998: Global warming and geothermal profiles: the surface rock-temperature response in South Africa. Geophysical Research Letters, 25, 2711-2714.

1997

Mason, S. J., 1997: Recent changes in El Nino-Southern Oscillation events and their implications for southern African climate. Transactions of the Royal Society of South Africa, 52, 377-403.

Mason, S. J., 1997: Review of recent developments in seasonal forecasting of rainfall. Water SA, 23, 57-62.

Mason, S. J., and A. M. Joubert, 1997: Simulated changes in extreme rainfall over southern Africa. International Journal of Climatology, 17, 291-301.

Mason, S. J., and M. R. Jury, 1997: Climatic change and inter-annual variability over southern Africa: a reflection on underlying processes. Progress in Physical Geography, 21, 23-50.

Tyson, P. D., A. P. Sturman, B. B. Fitzharris, S. J. Mason, and I. F. Owens, 1997: Circulation changes and teleconnections between glacial advances on the west coast of New Zealand and extended spells of drought years in South Africa. International Journal of Climatology, 17, 1499-1512.

1996

Joubert, A. M., S. J. Mason, and J. S. Galpin, 1996: Droughts over southern Africa in a doubled-CO₂ climate. International Journal of Climatology, 16, 1149-1156.

Mason, S. J., 1996: Climatic change over the Lowveld of South Africa. Climatic Change, 32, 35-54.

Mason, S. J., A. M. Joubert, C. Cosijn, and S. J. Crimp, 1996: Review of seasonal forecasting techniques and their applicability to southern Africa. Water SA, 22, 203-209.

1995

Mason, S. J., 1995: Sea surface temperature - South African rainfall associations, 1910-1989. International Journal of Climatology, 15, 119-135.

Mason, S. J., and A. M. Joubert, 1995: A note on rainfall variability and water demand in the Johannesburg region. Water SA, 21, 269-270.

1994

Mason, S. J., J. A. Lindesay, and P. D. Tyson, 1994: Simulating drought in southern Africa using sea surface temperature variations. Water SA, 20, 15-22.

1993

Mason, S. J., and J. A. Lindesay, 1993: A note on the modulation of Southern Oscillation-southern African rainfall associations with the Quasi-biennial Oscillation. Journal of Geophysical Research, 98 (D5), 8847-8850.

1992

Mason, S. J., and G. M. Mimmack, 1992: The use of bootstrap confidence intervals for the correlation coefficient in climatology. Theoretical and Applied Climatology, 45, 229-233.

Mason, S. J., and P. D. Tyson, 1992: The modulation of sea surface temperature and rainfall associations over southern Africa with solar activity and the Quasi-biennial Oscillation. Journal of Geophysical Research, 97 (D5), 5847-5856.

1991

1990

Mason, S. J., 1990: Temporal variability of sea surface temperatures around southern Africa: a possible forcing mechanism for the eighteen-year rainfall oscillation? South African Journal of Science, 86, 243-252.

Submitted and in press

Barnston, A. G., S. Li, S. J. Mason, D. G. DeWitt, L. Goddard, 2009: Verification of the first 11 years of IRI�s seasonal climate forecasts. Journal of Applied Meteorology and Climatology, submitted.