Assessment of the Off-season Rainfall of January to February 2020 and Its Socio Economic Implications in Tanzania: A Case Study of the Northern Coast of Tanzania

Kombo Hamad Kai (Tanzania Meteorological Authority (TMA), Zanzibar P. O. Box 340 Zanzibar, Tanzania)
Sarah E Osima (Tanzania Meteorological Authority (TMA), Zanzibar P. O. Box 340 Zanzibar, Tanzania)
Agnes Laurence Kijazi (TMA Dar es Salaam office, P. O. Box 3056 Ubungo Plaza, Tanzania)
Mohammed Khamis Ngwali (TMA Dar es Salaam office, P. O. Box 3056 Ubungo Plaza, Tanzania)
Asya Omar Hamad (Tanzania Meteorological Authority (TMA), Zanzibar P. O. Box 340 Zanzibar, Tanzania)

Abstract


This article examines the off season rainfall in northern coast Tanzania (NCT) including Zanzibar which occurred in January and February 2020 (JF). Like the JF rainfalls of 2001, 2004, 2010, 2016 and 2018, the JF (2020) rainfall was more unique in damages including loss of lives, properties and infrastructures. The study used the NCEP/NCAR reanalysis data to examine the cause of uniqueness of JF rainfall in 2001, 2004, 2010, 2016, 2018 and 2020 over NCT and Zanzibar. These datasets include monthly mean u, v wind at 850, 700, 500, and 200 mb; SSTs, mean sea level pressure (MSLP) anomalies, Dipole Mode Index (DMI), and monthly rainfall from NCT and Zanzibar stations. Datasets were processed and calculated into long term, seasonal, and monthly averages, indeed, Precipitation Index (PI) was calculated. Correlation analysis between the rainfall (December to January), SST, DMI and 850 mb wind vectors; and long-term percentage contribution of investigated parameters was calculated. Results revealed significant positive and negative correlations between JF rainfall, SSTs and DMI. Moreover, JFs of 2004 and 2016 had higher rainfalls of 443 mm with percentage contribution of up to 406%, while January and February, 2020 had the highest of 269.1 and 101.1mm in Zanzibar and 295 and 146.1 mm over and NCT areas, with highest January long-term rainfall contribution of 356% in Zanzibar and 526% over NCT. The DJF (2019/20) had the highest rainfall record of 649.5 mm in Zanzibar contributing up to 286%, while JF 2000 rainfall had a good spatial and temporal distribution over most NCT areas. JF, 2020 rainfall had impacts of more than 20 people died in Lindi and several infrastructures including Kiyegeya Bridge in Morogoro were damaged. Conclusively, more research works on understanding the dynamics of wet and dry JF seasons should be conducted.


Keywords


Indian ocean dipole;Dipole mode index (DMI);Sea surface temperatures (SSTs);Rainfall;Relative humidity;Correlations

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References


[1] Odekunle, TO. (2004), “Determining Rainfall Onset and Retreat Dates in Nigeria”, Journal of Humman Ecology 16(4): 239-247.

[2] Stine, AR. Huybers, P. & Fung, IY. (2009), “Changes in the phase of the annual cycle of surface temperature”, Nature 457, 435-440.

[3] Thomson, DJ. (2009), “ CLIMATE CHANGE Shifts in season”, NATURE| Vol 457|22 January 2009.

[4] Indrani, P. Bruce, TA. Guido, DS. and Daniel, JG. (2013),” Shifting seasonality and increasing frequency of precipitation in wet and dry seasons across the U.S”, Letters Volume. https://doi.org/10.1002/ grl.50760.

[5] Indeje, M.Semazzi, FHM and Ogalo, L. (2000),“ENSO signals in East African rainfall seasons” .International Journal of Climatology, Volume 20(1), pp 19-46. DOI: 10.1002/(SICI)1097-0088(200001)20:13.3.CO;2-S.

[6] Mapande, AT and Reason, CJC. (2005), “Inter annual rainfall variability over western Tanzania”, International Journal of Climatology 25: 1355-1368. Wiley Inter Science (www.interscience.wiley.com) DOI: 10.1002/joc.1193.

[7] Zorita, E. and Tilya, FF. (2002), “Rainfall variability in Northern Tanzania in the March-May season (long rains) and its links to large-scale climate forcing”,Climate Research (Clim Res) Vol. 20: 31-40, 2002. Pp 32-40.

[8] Anyah, R. O., and W. Qiu, 2012: Characteristic 20th and 21st century precipitation and temperature patterns and changes over the Greater Horn of Africa. Int. J. Climatol., 32, 347-363. DOI: 10.1002/joc.2270.

[9] Mahongo, SB. and Francis, J. (2012),” Analysis of Rainfall Variations and Trends in Coastal Tanzania”, Western Indian Ocean Journal of Marine Sciences. Vol. 11. No. 2, pp. 121-133, 2012.

[10] Kai, K.H., Kijazi, A.L. and Osima, S.E. (2020) An Assessment of the Seasonal Rainfall and Its Societal Implications in Zanzibar Islands during the Season of October to December, 2019. Atmospheric and Climate Sciences, 10, 509-529. https://doi.org/10.4236/ acs.2020.10402.

[11] Nicholson, SE. (2016), “An analysis of recent rainfall conditions in eastern Africa”, International Journal of Climatology., 36(1), 526-532. DOI: 10.1002/joc.4358.

[12] Chang’a, LB. Kijazi, AL. Luhunga, PM. Ng’ongolo, HK. and Mtongori, HI. (2017), “ Spatial and Temporal Analysis of Rainfall and Temperature Extreme Indices in Tanzania”, Atmospheric and Climate Sciences, 7, 525-539. https://doi.org/10.4236/ acs.2017.74038.

[13] Kijazi AL and Reason CJ. (2005). Relationships between intraseasonal rainfall variability of coastal Tanzania and ENSO. Theoretical and Applied Climatology volume 82, pp153-176.

[14] Sarah Osima, SE. Indasi,VS. Modathir Zaroug, M. Endris, HS. Gudoshava, M. Misiani, HO. Nimusiima, A. Anyah RO. Otieno, G. Ogwang, BA. Jain S8 .Kondowe, AL. Mwangi,E. Lennard, C. Nikulin, G. and Dosio, A. (2018), “Projected climate over the Greater Horn of Africa under 1.5°C and 2°C global warming”, Environment Research Letters, 13 (2018) 065004. https://doi.org/10.1088/1748-9326/aaba1b.

[15] Kai, KH. (2018), “Impacts of southwestern Indian Ocean tropical cyclones and storms on the rainfall pattern and vegetation productivity over Tanzania”. Thesis submitted to the institute of Marine Sciences of the University of Dar es Salaam. Dar es Salaam University press 297.

[16] MacLeod, D. (2018), “Seasonal predictability of onset and cessation of the east African rains”, Weather and Climate Extremes 21 (2018) 27-35. https://doi. org/10.1016/j.wace.2018.05.003.

[17] Owusu, A. Tesfamariam-Tekeste, Y. Ambani, M. Zebiak, S. Thomson, M. (2017),” Climate Services for Resilient Development (CSRD) Technical Exchange in Eastern Africa Workshop Report”. Technical report Climate Services for Resilient Development (CSRD), New York, USA.

[18] Latif, M. Dommenget D.,Dima, M. and Grotzner A. (1999),” The role of Indian Ocean sea surface temperature in forcing East African rainfall anomalies during December-January 1997”, Journal of Climate, 12, 3497-3504.

[19] Mavume, AF. Rydberg, L. Rouault, M and Lutjeharms, JRE. (2009), “Climatology and Landfall of Tropical Cyclones in the South western Indian Ocean”, Western Indian Ocean Journal of Marine Sciences , Vol. 8, No. 1, pp. 15-36.

[20] TMA Book (2019-2020), “Statement on the Status of Tanzania Climate in 2019”. http://meteo.go.tz/ uploads/publications/sw1586868749-Climate_statement_2019.pdf.

[21] Finney, DL Marsham, JH. Walker, DP. Birch, CE, Woodhams, BJ. Jackson, LS. and Hardy, S. (2019), “The effect of westerlies on East African rainfall and the associated role of tropical cyclones and the Madden Julian Oscillation”, Quarterly Journal of the Royal Meteorological Society. DOI: 10.1002/qj.3698.

[22] Black, E. Slingo, J. and Sperber, KR. (2003), “An Observational Study of the Relationship between Excessively Strong Short Rains in Coastal East Africa and Indian Ocean SST”, Monthly Weather Review Voumel 131 pp 74 - 94.

[23] TMA (2019) The October to December (OND) Seasonal Forecast for Tanzania. http://www.meteo.go.tz/ weather_forecasts/seasonal-weather-forecast.

[24] Nicholson, SE. (2017), “Climate and climatic variability of rainfall over eastern Africa”, Reviews of Geophysics, Volume 55, Issue 3 p. 590-635 https:// doi.org/10.1002/2016RG000544.

[25] Ashok, K., Z. Guan, and T. Yamagata, (2001), “Impact of the Indian Ocean dipole on the decadal relationship between the Indian monsoon rainfall and ENSO”,Geophys Research Letters., 28, 4499- 4502.

[26] Manatsa, D. Chipindu, B and Behera, S. (2012),“Shifts in IOD and their Impacts on Association with East Africa Rainfall”, Theoretical and Applied Climatology, 110(1-2). DOI:10.1007/s00704-012-0610-5.

[27] Kalnay, E. Kanamitsu, M. Kistler, R, Collins, W. Deaven, D. Gandin, L. Iredell, M. Saha, S. White, G. Woollen, J. Zhu, Y. Chelliah, M. Ebisuzaki, W. Higgins, W. Janowiak, J. Mo, KC.

[28] Saji, N.H., Goswami, B.N., Vinayachandran, P.N. and Yamagata, T. (1999) A Dipole Mode in the Tropical Indian Ocean. Nature , 401, 360-363. http://www.nature.com https://doi.org/10.1038/43854.

[29] Webster, PJ. Moore, AM. Loschnig, JP. Leben, RR. (1999), “Coupled ocean- atmosphere dynamics in the Indian Ocean during 1997-98”, Nature 401: 356-360.

[30] van Rooy, MP, (1965), “A rainfall anomaly index independent of time and space”, Notos, 14, 43.

[31] Byun, HiR. and Wilhite, DA. (1999), “Objective Quantification of Drought Severity and Duration”, Journal of Climate, Volume 12, pp 2747- 2756.

[32] McKee TB, Doesken NJ, Kleist J. 1993. The relationship of drought frequency and duration to time scales. Proceedings of the 8th Conference on Applied Climatology, American Meteorological Society, Boston: 179-184.

[33] McKee, TB. Doesken, NJ. Kleist, J. (1995), “Drought monitoring with multiple time scales”, Preprints, 9th Conference on Applied Climatology, 15-20 January, Dallas, Texas, American Meteorological Society: 233-236.

[34] Suzuki, R. Behera, SK. Lizuka, S. and Yamagata, T. (2004),” Indian Ocean Subtropical Dipole simulated using a coupled general circulation model”, Journal of Geophysical Research Atmospheres, Volume 109. DOI: 10.1029/2003JC001974.

[35] Matsumoto, S. and Ninomiya, K. (1996), “ Some Aspects of the Cloud Formation and Its Relation to the Heat and Moisture Supply from the Japan Sea Surface under a weak winter Monsoon Situation”, Journal of the Meteorological Society of Japan, Volume 44, No. 1 pp 60-74.

[36] Karan, H. Fitzpatrick, PJ. Hill, CM. and Li, Y. (2009), “The Formation of Multiple Squall Lines and the Impacts of WSR-88D Radial Winds in a WRF Simulation”, Weather and Forecasting, Volume 25 pp 242- 262.

[37] Kai, K.H., Ngwali, M.K. and Faki, M.M. (2021) Assessment of the Impacts of Tropical Cyclone Fantala to Tanzania Coastal Line: Case Study of Zanzibar. Atmospheric and Climate Sciences , 11, 245-266. https://doi.org/10.4236/acs.2021.112015.

[38] Cotton, WR. (1992), “Chapter 6 Cumulus Parameterization and Diagnostic Studies of Convective Systems” International Geophysics, Volume 44, pp 190- 300. https://doi.org/10.1016/S0074-6142(08)60545- 8. Available online 1 January 2009.

[39] Ogallo, LJ. (1983), “Quasi-periodic patterns in East African rainfall records”, Kenya Journal of Science and Technology, A3, pp 43 - 54.

[40] Beltrado, G. (1990), “Space-time variability in April and October-November over East Africa during the period 1932-1983”, Journal of Climatology, 10, pp 691 - 702.

[41] Goddard, L. and Graham, NE. (1999), ”Importance of the Indian Ocean for simulating rainfall anomalies over eastern and southern Africa”, Journal of Geophysical Research. 104D, 19 099-19 116.

[42] Ash, K.D and Matyas C.J. (2010),”The influence of ENSO and Subtropical Indian Ocean Dipole on tropical cyclone trajectories in the Southwestern Indian Ocean”, International Journal of Climatology, 32, pp 41-56.

[43] Ummenhofer, CC. Gupta, AS. England, MH. Reason, CJC. (2009), “Contributions of Indian Ocean Sea Surface Temperatures to Enhanced East African Rainfall”, Journal of Climate, Vol 22, pp 993 - 1013. DOI: 10.1175/2008JCLI2493.1.



DOI: https://doi.org/10.30564/jasr.v4i2.3135

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