The University of Melbourne Cyclone Detection and Tracking Algorithm

This website hosts the University of Melbourne cyclone detection and tracking algorithm developed by Murray and Simmonds (1991). The code-base has been updated in 2020 by Science IT, and is actively maintained at the University of Melbourne.

• The algorithm is designed to track low-pressure systems mainly in the extratropics, but also some tropical cyclones can be detected.
• The cyclone detection scheme locates maxima in the Laplacian of either mean sea level pressure or geopotential height at any pressure level.
• The average inflection point around the cyclone centre is used to define a cyclone radius, which can be adopted as impact area of a cyclone.
• The scheme can also be used to detect and track anticyclones. This can easily be done by changing the sign of the pressure (or geopotential) field and searching for ‘lows’.

Note that this algorithm is provided without any warranty, any updated manual and is to be used for non-profit applications only. The algorithm can be downloaded here.

The following list of publications either describe the scheme or its application. Please use at least one of these publications, when you are publishing results obtained with the provided algorithm.

Description of scheme

Murray, R.J. and Simmonds, I., 1991a: A numerical scheme for tracking cyclone centres from digital data. Part I: Development and operation of the scheme. Aust. Met. Mag., 39, 155-166. http://www.bom.gov.au/jshess/docs/1991/murray1.pdf.

Murray, R.J. and Simmonds, I., 1991b: A numerical scheme for tracking cyclone centres from digital data. Part II: Application to January and July general circulation model simulations. Aust. Met. Mag., 39, 167-180. http://www.bom.gov.au/jshess/docs/1991/murray2.pdf

Simmonds, I., Murray, R.J. and Leighton, R.M., 1999: A refinement of cyclone tracking methods with data from FROST. Aust. Met. Mag., Special Edition, 35-49. http://www.bom.gov.au/jshess/docs/1999/simmonds.pdf

Simmonds, I., 2000: Size changes over the life of sea level cyclones in the NCEP reanalysis. Monthly Weather Review, 128, 4118-4125, https://doi.org/10.1175/1520-0493(2000)129<4118:SCOTLO>2.0.CO;2.

Simmonds, I., and K. Keay, 2000: Mean Southern Hemisphere extratropical cyclone behavior in the 40-year NCEP-NCAR reanalysis. Journal of Climate, 13, 873-885, https://doi.org/10.1175/1520-0442(2000)013<0873:MSHECB>2.0.CO;2.

Lim, E.-P., and I. Simmonds, 2007: Southern Hemisphere winter extratropical cyclone characteristics and vertical organization observed with the ERA-40 reanalysis data in 1979-2001. Journal of Climate, 20, 2675-2690, https://doi.org/10.1175/JCLI4135.1.

Applications

Sato, K., J. Inoue, I. Simmonds and I. Rudeva, 2021: Antarctic Peninsula warm winters influenced by Tasman Sea temperatures. Nature Communications, 12, 1497, doi: 10.1038/s41467-021-21773-5.

Messmer, M., and I. Simmonds, 2021: Global analysis of cyclone-induced compound precipitation and wind extreme events. Weather and Climate Extremes, 32, 100324, doi: 10.1016/j.wace.2021.100324.

Earl, N., I. Simmonds and I. Rudeva, 2019: Sub-synoptic-scale features associated with extreme surface gusts during the South Australia Storm of September 2016: Part I. Characteristics of the event. Weather, 74, 278-285, doi:10.1002/wea.3385.

Grieger, J., G. C. Leckebusch, C. C. Raible, I. Rudeva and I. Simmonds, 2018: Subantarctic cyclones identified by 14 tracking methods, and their role for moisture transports into the continent. Tellus, 70A, 1454808, doi:10.1080/16000870.2018.1454808.

Screen, J. A., T. J. Bracegirdle and I. Simmonds, 2018: Polar climate change as manifest in atmospheric circulation. Current Climate Change Reports, 4, 383-395, doi: 10.1007/s40641-018-0111-4.

Kouroutzoglou, J., H. A. Flocas, M. Hatzaki, K. Keay, I. Simmonds and A. Mavroudis, 2015: On the dynamics of a case study of explosive cyclogenesis in the Mediterranean. Meteorology and Atmospheric Physics, 127, 49-73, doi:10.1007/s00703-014-0357-x.

Rudeva, I., and I. Simmonds, 2015: Variability and trends of global atmospheric frontal activity and links with large-scale modes of variability. Journal of Climate, 28, 3311-3330, doi:10.1175/JCLI-D-14-00458.1.

Simmonds, I., and I. Rudeva, 2014: A comparison of tracking methods for extreme cyclones in the Arctic basin. Tellus, 66A, 25252, doi: 10.3402/tellusa.v66.25252.

Papritz, L., S. Pfahl, I. Rudeva, I. Simmonds, H. Sodemann and H. Wernli, 2014: The role of extratropical cyclones and fronts for Southern Ocean freshwater fluxes. Journal of Climate, 27, 6205-6224, doi:10.1175/JCLI-D-13-00409.1.

Pezza, A. B., L. A. Garde, J. A. P. Veiga and I. Simmonds, 2014: Large scale features and energetics of the hybrid subtropical low ‘Duck’ over the Tasman Sea. Climate Dynamics, 42, 453-466, doi: 10.1007/s00382-013-1688-x.

Kouroutzoglou, J., H. A. Flocas, M. Hatzaki, K. Keay and I. Simmonds, 2014: A high-resolution climatological study on the comparison between surface explosive and ordinary cyclones in the Mediterranean. Regional Environmental Change, 14, 1833-1846, doi: 10.1007/s10113-013-0461-3.

Hatzaki, M., H. A. Flocas, I. Simmonds, J. Kouroutzoglou, K. Keay and I. Rudeva, 2014: Seasonal aspects of an objective climatology of anticyclones affecting the Mediterranean. Journal of Climate, 27, 9272-9289, doi: 10.1175/JCLI-D-14-00186.1.

Ulbrich, U., et al., 2013: Are greenhouse gas signals of Northern Hemisphere winter extra-tropical cyclone activity dependent on the identification and tracking algorithm? Meteorologische Zeitschrift, 22, 61-68, doi:10.1127/0941-2948/2013/0420.

Neu, U., M. G. Akperov, N. Bellenbaum, R. Benestad, R. Blender, R. Caballero, A. Cocozza, H. F. Dacre, Y. Feng, K. Fraedrich, J. Grieger, S. Gulev, J. Hanley, T. Hewson, M. Inatsu, K. Keay, S. F. Kew, I. Kindem, G. C. Leckebusch, M. L. R. Liberato, P. Lionello, I. I. Mokhov, J. G. Pinto, C. C. Raible, M. Reale, I. Rudeva, M. Schuster, I. Simmonds, M. Sinclair, M. Sprenger, N. D. Tilinina, I. F. Trigo, S. Ulbrich, U. Ulbrich, X. L. Wang and H. Wernli, 2013: IMILAST: A community effort to intercompare extratropical cyclone detection and tracking algorithms. Bulletin of the American Meteorological Society, 94, 529-547, doi: 10.1175/BAMS-D-11-00154.1

Flocas, H. A., P. Kountouris, J. Kouroutzoglou, M. Hatzaki, K. Keay and I. Simmonds, 2013: Vertical characteristics of cyclonic tracks over the eastern Mediterranean during the cold period of the year. Theoretical and Applied Climatology, 112, 375-388, doi: 10.1007/s00704-012-0737-4.

Kouroutzoglou, J., H. A. Flocas, K. Keay, I. Simmonds and M. Hatzaki, 2012: On the vertical structure of Mediterranean explosive cyclones. Theoretical and Applied Climatology, 110, 155–176, doi:10.1007/s00704-012-0620-3.

Simmonds, I., and I. Rudeva, 2012: The Great Arctic Cyclone of August 2012. Geophysical Research Letters, 39, L23709, doi:10.1029/2012GL054259.

Pezza, A. B., H. Rashid and I. Simmonds, 2012: Climate links and recent extremes in Antarctic sea ice, high-latitude cyclones, Southern Annular Mode and ENSO. Climate Dynamics, 38, 57-73, doi: 10.1007/s00382-011-1044-y.

Fogt, R. L., A. J. Wovrosh, R. A. Langen and I. Simmonds, 2012: The characteristic variability and connection to the underlying synoptic activity of the Amundsen-Bellingshausen Seas Low. Journal of Geophysical Research, 117, D07111, doi: 10.1029/2011JD017337.

Screen, J. A., I. Simmonds and K. Keay, 2011: Dramatic interannual changes of perennial Arctic sea ice linked to abnormal summer storm activity. Journal of Geophysical Research, 116, D15105, doi:10.1029/2011JD015847.

Uotila, P., T. Vihma, A. B. Pezza, I. Simmonds, K. Keay and A. H. Lynch, 2011: Relationships between Antarctic cyclones and surface conditions as derived from high resolution NWP data. Journal of Geophysical Research, 116, D07109, doi: 10.1029/2010JD015358.

Bromwich, D. H., D. F. Steinhoff, I. Simmonds, K. Keay and R. L. Fogt, 2011: Climatological aspects of cyclogenesis near Adélie Land Antarctica. Tellus, 63A, 921–938, doi: 10.1111/j.1600-0870.2011.00537.x.

Kouroutzoglou, J., H. A. Flocas, K. Keay, I. Simmonds and M. Hatzaki, 2011: Climatological aspects of explosive cyclones in the Mediterranean. International Journal of Climatology, 31, 1785–1802, doi: 10.1002/joc.2203.

Kouroutzoglou, J., H. A. Flocas, I. Simmonds, K. Keay and M. Hatzaki, 2011: Assessing characteristics of Mediterranean explosive cyclones for different data resolution. Theoretical and Applied Climatology, 105, 263-275, doi: 10.1007/s00704-010-0390-8.

Vianna, M. L., V. V. Menezes, A. B. Pezza and I. Simmonds, 2010: Interactions between Hurricane Catarina (2004) and warm core rings in the South Atlantic Ocean. Journal of Geophysical Research, 115, C07002, doi: 10.1029/2009JC005974.

Irving, D., I. Simmonds and K. Keay, 2010: Mesoscale cyclone activity over the ice-free Southern Ocean: 1999-2008. Journal of Climate, 23, 5404–5420, doi:10.1175/2010JCLI3628.1.

Pereira Filho, A. J., A. B. Pezza, I. Simmonds, R. S. Lima and M. Vianna, 2010: New perspectives on the synoptic and mesoscale structure of Hurricane Catarina. Atmospheric Research, 95, 157-171, doi: 10.1016/j.atmosres.2009.09.009.

Flocas, H. A., I. Simmonds, J. Kouroutzoglou, K. Keay, M. Hatzaki, V. Bricolas and D. Asimakopoulos, 2010: On cyclonic tracks over the eastern Mediterranean. Journal of Climate, 23, 5243–5257, doi: 10.1175/2010JCLI3426.1.

Lim, E.-P., and I. Simmonds, 2009: Effect of tropospheric temperature change on the zonal mean circulation and SH winter extratropical cyclones. Climate Dynamics, 33, 19-32, doi: 10.1007/s00382-008-0444-0.

Mesquita, M. d. S., D. E. Atkinson, I. Simmonds, K. Keay and J. Gottschalck, 2009: New perspectives on the synoptic development of the severe October 1992 Nome storm. Geophysical Research Letters, 36, L13808, doi: 10.1029/2009GL038824.

Pezza, A. B., I. Simmonds and A. J. Pereira Filho, 2009: Climate perspective on the large-scale circulation associated with the transition of the first South Atlantic hurricane. International Journal of Climatology, 29, 1116-1130, doi: 10.1002/joc.1757.

Simmonds, I., and K. Keay, 2009: Extraordinary September Arctic sea ice reductions and their relationships with storm behavior over 1979-2008. Geophysical Research Letters, 36, L19715, doi: 10.1029/2009GL039810.

Simmonds, I., C. Burke and K. Keay, 2008: Arctic climate change as manifest in cyclone behavior. Journal of Climate, 21, 5777-5796, doi:10.1175/2008JCLI2366.1.

Pezza, A. B., and I. Simmonds, 2008: Large-scale factors in tropical and extratropical cyclone transition and extreme weather events. Annals of the New York Academy of Sciences, 1146, 189-211, doi: 10.1196/annals.1446.005.

Pezza, A. B., T. Durrant, I. Simmonds and I. Smith, 2008: Southern Hemisphere synoptic behavior in extreme phases of SAM, ENSO, sea ice extent and southern Australia rainfall. Journal of Climate, 21, 5566-5584, doi: 10.1175/2008JCLI2128.1

Pezza, A. B., I. Simmonds and J. A. Renwick, 2007: Southern Hemisphere cyclones and anticyclones: Recent trends and links with decadal variability in the Pacific Ocean. International Journal of Climatology, 27, 1403-1419, doi:10.1002/joc.1477.

Lim, E.-P., and I. Simmonds, 2007: Southern Hemisphere winter extratropical cyclone characteristics and vertical organization observed with the ERA-40 reanalysis data in 1979-2001. Journal of Climate, 20, 2675-2690, https://doi.org/10.1175/JCLI4135.1.

Wassermann, S., C. Schmitt, C. Kottmeier and I. Simmonds, 2006: Coincident vortices in Antarctic wind fields and sea ice motion. Geophysical Research Letters, 33, L15810, https://doi.org/10.1029/2006GL026005.

White, W. B., and I. Simmonds, 2006: Sea surface temperature-induced cyclogenesis in the Antarctic circumpolar wave. Journal of Geophysical Research, 111, C08011, https://doi.org/10.1029/2004JC002395.

Pezza, A. B., and I. Simmonds, 2005: The first South Atlantic hurricane: Unprecedented blocking, low shear and climate change. Geophysical Research Letters, 32, , L15712, https://doi.org/10.1029/2005GL023390.

Simmonds, I., 2003: Modes of atmospheric variability over the Southern Ocean. Journal of Geophysical Research, 108, 8078, https://doi.org/10.1029/2000JC000542.

Lim, E.-P., and I. Simmonds, 2002: Explosive cyclone development in the Southern Hemisphere and a comparison with Northern Hemisphere events. Monthly Weather Review, 130, 2188-2209, https://doi.org/10.1175/1520-0493(2002)130<2188:ECDITS>2.0.CO;2.

Murphy, B. F., P. Pettré and I. Simmonds, 2002: Effects of changing baroclinicity on the southern hemisphere extratropical circulation. Quarterly Journal of the Royal Meteorological Society, 128, 1807-1826, https://doi.org/10.1256/003590002320603421.

Keable, M., I. Simmonds and K. Keay, 2002: Distribution and temporal variability of 500 hPa cyclone characteristics in the Southern Hemisphere. International Journal of Climatology, 22, 131-150, https://doi.org/10.1002/joc.728.

Simmonds, I., 2000: Size changes over the life of sea level cyclones in the NCEP reanalysis. Monthly Weather Review, 128, 4118-4125, doi:10.1175/1520-0493(2000)129%3C4118:SCOTLO%3E2.0.CO;2.

Simmonds, I., and K. Keay, 2000: Mean Southern Hemisphere extratropical cyclone behaviour in the 40-year NCEP-NCAR reanalysis. Journal of Climate, 13, 873-885, doi:10.1175/1520-0442(2000)013<0873:MSHECB>2.0.CO;2.

Simmonds, I., and K. Keay, 2000: Variability of Southern Hemisphere extratropical cyclone behaviour 1958-97. Journal of Climate, 13, 550-561, doi:10.1175/1520-0442(2000)013<0550:VOSHEC>2.0.CO;2.

Simmonds, I., and R. J. Murray, 1999: Southern extratropical cyclone behavior in ECMWF analyses during the FROST Special Observing Periods. Weather and Forecasting, 14, 878-891, https://doi.org/10.1175/1520-0434(1999)014<0878:SECBIE>2.0.CO;2.

Godfred-Spenning, C. R., and I. Simmonds, 1996: An analysis of Antarctic sea-ice and extratropical cyclone associations. International Journal of Climatology, 16, 1315-1332, https://doi.org/10.1002/(SICI)1097-0088(199612)16:12<1315::AID-JOC92>3.0.CO;2-M.

Murray, R. J., and I. Simmonds, 1995: Responses of climate and cyclones to reductions in Arctic winter sea ice. Journal of Geophysical Research, 100, 4791-4806, https://doi.org/10.1029/94JC02206.

Jones, D. A., and I. Simmonds, 1994: A climatology of Southern Hemisphere anticyclones. Climate Dynamics, 10, 333-348, https://doi.org/10.1007/BF00228031.

Jones, D. A., and I. Simmonds, 1993: A climatology of Southern Hemisphere extratropical cyclones. Climate Dynamics, 9, 131-145, https://doi.org/10.1007/BF00209750.

Simmonds, I., and X. Wu, 1993: Cyclone behaviour response to changes in winter Southern Hemisphere sea-ice concentration. Quarterly Journal of the Royal Meteorological Society, 119, 1121-1148, https://doi.org/10.1002/qj.49711951313.

Many people have contributed to the development of this scheme over the last three decades. These include in alphabetical order:

Ahmad Galea, Damien Irving, David Jones, Murray Keable, Kevin Keay, John Kouroutzoglou, Eun-Pa Lim, Michel Mesquita, Martina Messmer, Ross Murray, Acacia Pepler, Alex Pezza, Irina Rudeva, Petteri Uotila, and many more.