Climate change has resulted in serious social-economic ramifications and extremely catastrophic weather events in the world, Tanzania and Zanzibar in particular, with adaptation being the only option to reduce impacts. The study focuses on the influence of climate change and variability on spatio-temporal rainfall and temperature variability and distribution in Zanzibar. The station observation datasets of rainfall, T max and T min acquired from Tanzania Meteorological Authority (TMA) and the Coordinated Regional Climate Downscaling Experiment program (CORDEX) projected datasets from the Regional climate model HIRHAM5 under driving model ICHEC-EC- EARH, for the three periods of 1991-2020 used as baseline (HS), 2021-2050 as near future (NF) and 2051-2080 far future (FF), under two representative concentration pathways (RCP) of 4.5 and 8.5, were used. The long-term observed T max and T min were used to produce time series for observing the nature and trends, while the observed rainfall data was used for understanding wet and dry periods, trends and slope (at p ≤ 0.05) using the Standardized Precipitation Index (SPI) and the Mann Kendall test (MK). Moreover, the Quantum Geographic Information System (QGIS) under the Inverse Distance Weighting (IDW) interpolation techniques w ere used for mapping the three decades of 1991-2000 (hereafter D1), 2001 - 2010 (hereafter D2) and 2011-2020 (hereafter D3) to analyze periodical spatial rainfall distribution in Zanzibar. As for the projected datasets the Climate Data Operator Commands (CDO), python scripts and Grid analysis and Display System (GrADS) soft-wares were used to process and display the results of the projected datasets of rainfall, T max and T min for the HS, NF and FF, respectively. The results show that the observed T max increased by the rates of 0.035℃ yr - 1 and 0.0169℃ yr - 1 , while the T min was increased by a rate of 0.064℃ yr - 1 and 0.104℃ yr - 1 for Unguja and Pemba, respectively. The temporal distribution of wetness and dryness indices showed a climate shift from near normal to moderate wet during 2005 at Zanzibar Airport, while normal to moderately dry conditions, were observed in Pemba at Matangatuani. The decadal rainfall variability and distributions revealed higher rainfall intensity with an increasing trend and good spatial distribution in D3 from March to May (MAM) and October to December (OND). The projected results for T max during MAM and OND depicted higher values ranging from 1.7℃ - 1.8℃ to 1.9℃ - 2.0℃ and 1.5℃ to 2.0℃ in FF compared to NF under both RCPs. Also, higher T min values of 1.12℃ - 1.16℃ was projected in FF for MAM and OND under both RCPs. Besides, the rainfall projection generally revealed increased rainfall intensity in the range of 0 - 25 mm for Pemba and declined rainfall in the range of 25 - 50 mm in Unguja under both RCPs in perspectives of both NF and FF. Conclusively the study has shown that the undergoing climate change has posed a significant impact on both rainfall and temperature spatial and temporal distributions in Zanzibar (Unguja and Pemba), with Unguja being projected to have higher rainfall deficits while increasing rainfall strengths in Pemba. Thus, the study calls for more studies and formulation of effective adaptation, strategies and resilience mechanisms to combat the projected climate change impacts especially in the agricultural sector, water and food security.
IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, 996.
Intergovernmental Panel on Climate Change (IPCC) (2013) Climate Change 2013: The Physical Science Basis. Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge. https://doi.org/10.1017/CBO9781107415324
Collins, J.M. (2011) Temperature Variability over Africa. Journal of Climate, 24, 3649-3666. https://doi.org/10.1175/2011JCLI3753.1
Sutton, R.T., Dong, B. and Gregory, J.M. (2007) Land/Sea Warming Ratio in Response to Climate Change: IPCC AR4 Model Results and Comparison with Observations. Geophysical Research Letters, 34, L02701. https://doi.org/10.1029/2006GL028164
Osima, S., Indasi, V.S., Zaroug, M., Endris, H.S., Gudoshava, M., Misiani, H.O., Nimusiima, A., Anyah, R.O., Otieno, G., Ogwang, B.A. and Jain, S. (2018) Projected Climate over the Greater Horn of Africa under 1.5℃ and 2℃ Global Warming. Environmental Research Letters, 13, Article ID: 065004. https://doi.org/10.1088/1748-9326/aaba1b
Ahmed, S.A., Diffenbaugh, N.S. and Hertel, T.W. (2009) Climate Volatility Deepens Poverty Vulnerability in Developing Countries. Environmental Research Letters, 4, Article ID: 034004. https://doi.org/10.1088/1748-9326/4/3/034004
Hansen, J., Ruedy, R., Sato, M. and Lo, K. (2010) Global Surface Temperature Change. Reviews of Geophysics, 48, RG4004. https://doi.org/10.1029/2010RG000345
Ouarda, T.B., Charron, C., Kumar, K.N., Marpu, P.R., Ghedira, H., Molini, A. and Khayal, I. (2014) Evolution of the Rainfall Regime in the United Arab Emirates. Journal of Hydrology, 514, 258-270. https://doi.org/10.1016/j.jhydrol.2014.04.032
Baigorria, G.A. and Jones, J.W. (2010) GiST: A Stochastic Model for Generating Spatially and Temporally Correlated Daily Rainfall Data. Journal of Climate, 23, 5990-6008. https://doi.org/10.1175/2010JCLI3537.1
Raziei, T., Daryabari, J., Bordi, I. and Pereira, L.S. (2014) Spatial Patterns and Temporal Trends of Precipitation in Iran. Theoretical and Applied Climatology, 115, 531-540. https://doi.org/10.1007/s00704-013-0919-8
Nam, W. and Baigorria, G.A. (2015) How Climate Change Has Affected the Spatio-Temporal Patterns of Precipitation and Temperature at Various Time Scales in North Korea. International Journal of Climatology, 36, 722-734. https://doi.org/10.1002/joc.4378
KeywordsClimate ChangeClimate VariabilitySpatial and Temporal DistributionTemperatureRainfallCORDEX
Field, C.B. and Barros, V.R. (2014) Climate Change 2014-Impacts, Adaptation and Vulnerability: Regional Aspects. Cambridge University Press, Cambridge.
Tierney, J.E., Ummenhofer, C.C. and Demenocal, P.B. (2015) Past and Future Rainfall in the Horn of Africa. Science Advances, 1, e1500682. https://doi.org/10.1126/sciadv.1500682
Gebrechorkos, S.H., Hülsmann, S. and Bernhofer, C. (2019) Long-Term Trends in Rainfall and Temperature Using High-Resolution Climate Datasets in East Africa. Scientific Reports, 9, Article No. 11376. https://doi.org/10.1038/s41598-019-47933-8
Endris, H.S., Lennard, C., Hewitson, B., Dosio, A., Nikulin, G. and Panitz, H.J. (2016) Teleconnection Responses in Multi-GCM Driven CORDEX RCMs over Eastern Africa. Climate Dynamics, 46, 2821-2846. https://doi.org/10.1007/s00382-015-2734-7
Fer, I., Tietjen, B., Jeltsch, F. and Wolff, C. (2017) The Influence of El Niño-Southern Oscillation Regimes on Eastern African Vegetation and Its Future Implications under the RCP8.5 Warming Scenario. Biogeosciences, 14, 4355-4374. https://doi.org/10.5194/bg-14-4355-2017
Mpelasoka, F., Awange, J.L. and Zerihun, A. (2018) Influence of Coupled Ocean-Atmosphere Phenomena on the Greater Horn of Africa Droughts and Their Implications. Science of the Total Environment, 610, 691-702. https://doi.org/10.1016/j.scitotenv.2017.08.109
Endris, H.S., Omondi, P., Jain, S., Lennard, C., Hewitson, B., Chang’a, L., Awange, J.L., Dosio, A., Ketiem, P., Nikulin, G. and Panitz, H.J. (2013) Assessment of the Performance of CORDEX Regional Climate Models in Simulating East African Rainfall. Journal of Climate, 26, 8453-8475. https://doi.org/10.1175/JCLI-D-12-00708.1
Kai, K.H., Kijazi, A.L. and Osima, S.E. (2020) An Assessment of the Seasonal Rainfall and 16 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.2020.104026
Hassan, I.H., Mdemu, M.V., Shemdoe, R.S. and Stordal, F. (2014) Drought Pattern along the Coastal Forest Zone of Tanzania. Atmospheric and Climate Sciences, 4, 369-384. https://doi.org/10.4236/acs.2014.43037
Mtongori, H.I., Stordal, F. and Benestad, R.E. (2016) Evaluation of Empirical Statistical Downscaling Models’ Skill in Predicting Tanzanian Rainfall and Their Application in Providing Future Downscaled Scenarios. Journal of Climate, 29, 3231-3252. https://doi.org/10.1175/JCLI-D-15-0061.1
Chikodzi, D., Murwendo, T. and Simba, F.M. (2013) Climate Change and Variability in Southeast Zimbabwe: Scenarios and Societal Opportunities. American Journal of Climate Change, 2, 36-46. https://doi.org/10.4236/ajcc.2013.23A004
Kai, K.H., Osima, S.E., Kijazi, A.L., Ngwali, M.K. and Hamad, A.O. (2021) 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. Journal of Atmospheric Science Research, 4, 51-69. https://doi.org/10.30564/jasr.v4i2.3135
OCGS (Office of the Chief Government Statistician) (2022) Zanzibar in Figures, 2022.
Kijazi, A.L. and Reason, C.J.C. (2005) Relationships between Intraseasonal Rainfall Variability of Coastal Tanzania and ENSO. Theoretical and Applied Climatology, 82, 153-176. https://doi.org/10.1007/s00704-005-0129-0
Mahongo, S.B., Francis, J. and Osima, S.E. (2011) Wind Patterns of Coastal Tanzania: Their Variability and Trends. Western Indian Ocean Journal of Marine Science, 10, 107-120.
Watkiss, P., Pye, S., Hendriksen, G., Maclean, A., Bonjean, M., Jiddawi, N., Shaghude, Y. and Sheikh, M.A. (2012) The Economics of Climate Change in Zanzibar. 1-36.
McKee, T.B., Doesken, N.J. and Kleist, J. (1993) The Relationship of Drought Frequency and Duration to Time Scales. In: Proceedings of the 8th Conference on Applied Climatology, American Meteorological Society, Boston, 179-184.
WMO (2012) Standardized Precipitation Index User Guide 1090. https://www.droughtmanagement.info/literature/WMO_standardized_precipitation_index_user_guide_en_2012.pdf
Lukali, A.A., Osima, S.E., Lou, Y. and Kai, K.H. (2021) Assessing the Impacts of Climate Change and Variability on Maize (Zea mays) Yield over Tanzania. Atmospheric and Climate Sciences, 11, 569-588. https://doi.org/10.4236/acs.2021.113035
Agbo, E.P., Ekpo, C.M. and Edet, C.O. (2021) Analysis of the Effects of Meteorological Parameters on Radio Refractivity, Equivalent Potential Temperature and Field Strength via Mann-Kendall Test. Theoretical and Applied Climatology, 143, 1437-1456. https://doi.org/10.1007/s00704-020-03464-1
Hayelom, B., Chen, Y., Marsie, Z. and Negash, M. (2017) Temperature and Precipitation Trend Analysis over the Last 30 Years in Southern Tigray Regional State, Ethiopia. https://doi.org/10.20944/preprints201702.0014.v1
Wu, Y., Wang, W. and Wang, G. (2016) Detecting Variation Trends of Temperature and Precipitation for the Dadu River Basin, China. Advances in Meteorology, 2016, Article ID: 2564586. https://doi.org/10.1155/2016/2564586
Arora, M., Goel, N.K. and Singh, P. (2005) Evaluation of Temperature Trends over India/Evaluation de tendances de température en Inde. Hydrological Sciences Journal, 50, 93. https://doi.org/10.1623/hysj.50.1.81.56330
Fan, X.H. and Wang, M.B. (2011) Change Trends of Air Temperature and Precipitation over Shanxi Province, China. Theoretical and Applied Climatology, 103, 519-531. https://doi.org/10.1007/s00704-010-0319-2
Kisi, O. and Ay, M. (2014) Comparison of Mann-Kendall and Innovative Trend Method for Water Quality Parameters of the Kizilirmak River, Turkey. Journal of Hydrology, 513, 362-375. https://doi.org/10.1016/j.jhydrol.2014.03.005
Pal, A.B., Khare, D., Mishra, P.K. and Singh, L. (2017) Trend Analysis of Rainfall, Temperature and Runoff Data: A Case Study of Rangoon Watershed in Nepal. International Journal of Students’ Research in Technology & Management, 5, 21-38. https://doi.org/10.18510/ijsrtm.2017.535
Dawood, M., Mahmood, S., Rahman, G. and Rahman, A.U. (2017) Impact of Rainfall Fluctuation on River Discharge in Hindu Kush Region, Pakistan. Abasyn Journal of Social Sciences, 10, 246-259.
Mandale, V.P., Mahale, D.M., Nandgude, S.B., Gharde, K.D. and Thokal, R.T. (2017) Spatio-Temporal Rainfall Trends in Konkan Region of Maharashtra State. Advanced Agricultural Research & Technology Journal, 1, 61-69.
Mandale, V.P., Mahale, D.M., Nandgude, S.B., Gharde, K.D. and Thokal, R.T. (2017) Spatio-Temporal Rainfall Trends in Konkan Region of Maharashtra State. Advanced Agricultural Research & Technology Journal, 1, 61-69.
Sen, P.K. (1968) Estimates of the Regression Coefficient Based on Kendall’s Tau. Journal of the American Statistical Association, 63, 1379-1389. https://doi.org/10.1080/01621459.1968.10480934
Longley, P.A., Goodchild, M.F., Maguire, D.J. and Rhind, D.W. (2001) New Developments in Geographical Information Systems; Principles, Techniques, Management and Applications. In: Longley, P., Ed., Geographical Information Systems: Principles, Techniques, Management and Applications, 2nd Edition, John Wiley & Sons Inc., Hoboken, 404.
Debnath, P. (2022) A QGIS-Based Road Network Analysis for Sustainable Road Network Infrastructure: An Application to the Cachar District in Assam, India. Infrastructures, 7, 114. https://doi.org/10.3390/infrastructures7090114
Setianto, A. and Triandini, T. (2013) Comparison of Kriging and Inverse Distance Weighted (IDW) Interpolation Methods in Lineament Extraction and Analysis. Journal of Applied Geology, 5. https://doi.org/10.22146/jag.7204
Paramasivam, C.R. and Venkatramanan, S. (2019) An Introduction to Various Spatial Analysis Techniques. In: Venkatramanan, S., Prasanna, M.V. and Chung, S.Y., Eds., GIS and Geostatistical Techniques for Groundwater Science, Elsevier, Amsterdam, 23-30. https://doi.org/10.1016/B978-0-12-815413-7.00003-1
Chang’a, L.B., Kijazi, A.L., Luhunga, P.M., Ng’ongolo, H.K. and Mtongori, H.I. (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
Luhunga, P.M., Kijazi, A.L., Chang’a, L., Kondowe, A., Ng’ongolo, H. and Mtongori, H. (2018) Climate Change Projections for Tanzania Based on High-Resolution Regional Climate Models from the Coordinated Regional Climate Downscaling Experiment (CORDEX)-Africa. Frontiers in Environmental Science, 6, 122. https://doi.org/10.3389/fenvs.2018.00122
IPCC (2012) Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. In: Field, C.B., Barros, V., Stocker, T.F., et al., Eds., A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge.