A preliminary study of climatological associations and characteristics of tropical cyclones in the SW Indian Ocean
- Mark R. Jury
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Tropical cyclones (TC) in the data-sparse SW Indian Ocean region are studied through climatological and statistical associations and case study structure. Differences between summers with more and less TC are identified with a view to the prediction of seasonal frequencies. In summers with more TC, upper easterlies and lower westerlies over the equatorial zone north of Madagascar form a Walker cell anomaly in conjunction with the east phase of the stratospheric quasi-biennial oscillation (QBO), while sea surface temperatures (SST) are above normal in the preceding spring (>28°C). In the sub-tropics, easterly trade winds strengthen while mid-latitude westerlies shift polewards and SST are below normal (<23°C). OLR departures in “more TC” summers are <−15 Wm−2 over region frequented by tropical cyclones.
Two tropical cyclone events are selected for analysis which rank highest in terms of rainfall on Mauritius. Danielle formed near 13°S, 65°E and tracked southwest across Mauritius on 19 January 1964. A radiosonde time-height section is analysed for departures from climatology and thermodynamic structure. The profile of equivalent potential temperature is rather uniform near the center of the TC, decreasing from 350°K near the surface. Dry stable air is present in the 600hPa layer around the perimeter. TC Hyacinthe was quasistationary to the east of Madagascar causing rainfall in excess of 500 cm on Reunion Island from 15–27 January 1980. OLR anomaly plots and satellite imagery indicate that Hyacinthe was spawned in association with an eastward moving convective wave and reached maximum intensity (−92 Wm−2) and radius (>1000 km) from 21 to 26 January 1980.
- Anthes, R. A., 1982: Tropical cyclones, their evolution, structure and effects,Met Mon 19, 41, Amer Meteorol Soc, Boston, 208 pp.
- Appadu, S. N. S., 1980: Effects of rainfall associated with tropical cyclone Hyacinthe. Mauritius Meteorological Services,Internal Rep, Vacoas, Mauritius, 19 pp.
- Appadu, S. N. S., Goolaup, P., 1991. Cyclone season of the Southwest Indian Ocean 1990–1991.Technical Rep CS 14, Mauritius Meteorological Services, Vacoas, Mauritius.
- Barnes, G. M., Zipser, E. J., Jorgensen, D., Marks, F., Jr., 1983: Mesoscale and convective structure of a hurricane rainband.J. Atmos. Sci.,40 (9), 2125–2137.
- Chen, T.-C., Tzeng, R.-Y., 1990: Global-scale intra-seasonal and annual variation of divergent water-vapor flux.Meterol. Atmos. Phys.,44, 133–151.
- Crutcher, H. L., Quayle, R. G., 1973: Mariners worldwide climatic guide to tropical storms at sea. Washington: Naval Weather Service, 426 pp.
- Dvorak, V. F., 1975: Tropical cyclone intensity analysis and forecasting from satellite imagery.Mon. Wea. Rev.,103, 420–430.
- Ecormier, J., 1992: Tropical cyclones of the Southwest Indian Ocean, cases affecting Reunion island.Tech. Rep., Meteo. France, Reunion, 479 pp.
- Gray, W. M., 1981: Recent advances in tropical cyclone research from rawinsonde composite analysis.WMO Tech Rep, Geneva, Switzerland, 407 pp.
- Gray, W. M., 1984: Atlantic seasonal hurricane frequency: 1, El Nino and 30 mb quasi-biennial oscillation influences.Mon. Wea. Rev.,112, 1649–1668.
- Hastenrath, S., 1985:Climate and Circulation of the Tropics. Doordrecht: D. Riedel, 455 pp.
- Hawkins, H. F., Imbembo, S. M., 1976: The structure of a small intense hurricane-Inez 1966.Mon. Wea. Rev.,104, 418–442.
- Jury, M. R., Pathack, B., 1991: A study of climate and weather variability over the tropical SW Indian Ocean.Meteorol. Atmos. Phys.,47, 37–48.
- Jury, M. R., Pathack, B., Wang, B., Landman, W., 1991: Transient convective waves in the tropical SW Indian Ocean.Meteorol. Atmos Phys.,47, 27–36
- Jury, M. R., Pathack, B., Wang, B., Powell, M., Raholijao, N., 1992: A destructive tropical cyclone season in the SW Indian Ocean: January–February 1984.S.A. Geogr. J. (in press).
- Mauritius Meteorological Service, 1982: The cyclone season in the SW Indian Ocean 1979–1980.Tech Rep CS 5, Vacoas, Mauritius.
- Merrill, R. T., 1988: Characteristics of upper-tropospheric environmental flow around hurricanes.J. Atmos. Sci.,45 (11), 1665–1677.
- Merrill, R. T., 1991: Physical retrieval of typhoon structure using passive microwave observations. Proc 19th Conf Hurr Tropical Meteorol, AMS, Miami, 405–408.
- National Oceanic and Atmospheric Administration, 1980: Environmental Satellite Imagery, January 1980, Washington DC, 96 pp.
- Padya, B. M., 1989:Weather and Climate of Mauritius. Mauritius: M. Gandhi Inst., 283 pp.
- Pathack, B. M. R., 1993: Modulation of South African summer rainfall by global climatic processes.PhD Thesis, Oceanogr Dept, Univ Cape Town, (in press).
- Riehl, H., 1979.Climate and Weather of the Tropics. London: Academic Press, 611 pp.
- Rossow, W. B., Schiffer, R. A., 1991: ISCCP cloud data products.Bull. Amer. Meteor. Soc.,72, 2–20.
- South Africa Weather Bureau, 1972: Daily weather maps.Notos, Pretoria.
- Velden, C. S., Leslie, L. M., 1991: The basic relationship between tropical cyclone intensity and the depth of the environmental steering layer in the Australian region.Weather and Forecasting,6, 244–253.
- Wang, B., Rui, H., 1990: Synoptic climatology of transient tropical intra-seasonal convective anomalies: 1975–1984.Meteorol. Atmos. Phys.,44, 43–61.
- Weatherford, C. I., Gray, W. M., 1988: Typhoon structure as revealed by aircraft reconnaissance 1: data analysis and climatology.Mon. Wea. Rev.,116, (5), 1032–1043.
- World Meteorological Organization, 1992: Tropical cyclone operational plan for the south-west Indian Ocean.Technical Report 618, draft revision with appendices, Geneva, Switzerland.
- A preliminary study of climatological associations and characteristics of tropical cyclones in the SW Indian Ocean
Meteorology and Atmospheric Physics
Volume 51, Issue 1-2 , pp 101-115
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- Mark R. Jury (1)
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- 1. Oceanography Department, University of Cape Town, 7700, Rondebosch, South Africa