Assessing Prone Areas to Heavy Rainfall and the Impaction of the Upper Warm Temperature Anomaly during March–May Rainfall Season in Tanzania

Mafuru, Kantamla Biseke; Tan, Guirong

doi:10.1155/2018/8353296

Cited by 27 publications

(26 citation statements)

References 48 publications

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“…[25] assumed that the point is the approximate year when the trend begins, while [26] referred to it as the period at which the critical point of change occurs. [27] noted that, extreme weather events (i.e., heavy rainfall events) reveals an alarming increasing in trend over most area in Tanzania.…”

Section: Contribution Of Mam Rainfall To the Mean Annual Rainfallmentioning

confidence: 99%

Understanding the Evolution and Socio-Economic Impacts of the Extreme Rainfall Events in March-May 2017 to 2020 in East Africa

Chang’a¹,

Kijazi²,

Mafuru³

et al. 2020

ACS

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This study aimed at assessing the evolution, distribution and the socioeconomic impacts of extreme rainfall over East Africa during the March, April and May (MAM) rainfall season focusing on assessing the trends and contribution of MAM rainfall in mean annual rainfall across the region. It employed Principal Component Analysis (PCA) methods to capture the patterns and variability of MAM rainfall. The PCA results indicated that the first Principal Component (PC) describe 17% of the total variance, while the first six PCs account only 53.5% of the total variance in MAM rainfall, underscoring the complexity of rainfall forcing factors in the region. It has been observed that MAM rainfall accounts about 30%-60% of the mean annual rainfall in most parts of the region, signifying its importance in agriculture, water, energy and other socioeconomic sectors. MAM has been characterized by increasing variability with varying trend patterns across the region. The MAM rainfall trend is not homogeneous across the region; some areas are experiencing a slight decreasing rainfall trend, while other areas are experiencing a slight increasing rainfall trend. The observed trend dynamics is consistent with the global trend patterns in precipitation as depicted in recent Intergovernmental Panel on Climate Change (IPCC) reports. Over the last five years MAM rainfall season have been characterized by record-breaking extremes. On 8 th May 2017, Tanga and Mombasa meteorological stations recorded 316 mm

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Section: Contribution Of Mam Rainfall To the Mean Annual Rainfallmentioning

confidence: 99%

Understanding the Evolution and Socio-Economic Impacts of the Extreme Rainfall Events in March-May 2017 to 2020 in East Africa

Chang’a¹,

Kijazi²,

Mafuru³

et al. 2020

ACS

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“…unimodal and bimodal regime due to north-south movement of Inter tropical convergence zone, ITCZ (Clark et al, 2003). The north, northeastern and eastern area experiences bimodal rainy seasons during October-December (short rainy, OND) and March-May (long rainy, MAM) while southwestern highlands, western and some parts of Lake Victoria experience unimodal rainfall pattern during October/November to April/May (Kabanda & Jury, 1999;Mafuru & Guirong, 2018).…”

Section: Study Areamentioning

confidence: 99%

“…The study utilized monthly observation rainfall data of 20 scattered synoptic stations (Figure 1b) from the Tanzania Meteorological Agency (TMA) for 40 years . The synoptic stations dataset used in this study represent eleven (11) homogeneous climatological zones in the country (Kijazi & Reason, 2011;Mafuru & Guirong, 2018). Despite that, precipitation gridded data set from the Climate Research Unit (CRU) version 4.02 (CRU TV v.4.02) with a resolution of 0.5º x 0.5º from 1978 to 2017 was used in this study.…”

Section: Datamentioning

confidence: 99%

Inter-annual variability of March to May rainfall over Tanzania and its association with atmospheric circulation anomalies

King’uza¹,

Tilwebwa²

2019

Geographica Pannonica

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This study used Empirical Orthogonal Function (EOF), student t test, composite and correlation analysis techniques to investigate the inter-annual variability of March to May rainy season over Tanzania and its association atmospheric circulation anomalies. The EOF results showed that the rainfall over Tanzania during MAM season does not vary too much with the first dominant mode (EOF1) showing the variance of 22.4% of the total rainfall and that much of the rainfall being concentrated over the coast, northeastern and southern regions. It was found that during wet years, the study area was dominated by convergence at lower level which is associated with enough moisture advected by south easterlies from Indian Ocean due to the relaxation of Mascarene high (MH) over the region and westerlies from Congo basin. The rising motion at lower level was enhanced with the presence of ascending limb of Walker circulation cell over the western Indian Ocean (WIO) and the coast region. Central Pacific and east coast of Atlantic Oceans are relatively warm during wet years. Furthermore, significantly negative correlation observed between southeast Indian Ocean (SEIO) region and MAM rainfall over Tanzania at the 95% confidence level portrays that much of the regions receive high sufficient amount of rainfall when the western Indian Ocean (WIO) is relatively warmer than the SEIO. The results show that Nino 3.4 and Tropical North Atlantic (TNA) indices are strongly positively correlated with MAM rainfall over the east coast region. This study will help to improve seasonal forecasts over Tanzania.

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“…The heavier and long lasting March to May (MAM) “long rain” remains the major East African Agricultural season (e.g., Camberlin and Philippon, ) where its excessive has a profound adverse effects on agricultural products and peoples livelihood. In our recent study (e.g., Mafuru and Guirong, ), we have found an increasing trend of heavy rainfall events (HREs) in Tanzania during MAM. The increase in HREs were found to be associated with low level westerly convergence, advection of moisture from both the Indian Ocean and Congo basin, pronounced rising motion, intensified and well positioned ITCZ over the country.…”

Section: Introductionmentioning

confidence: 98%

The influence of ENSO on the upper warm temperature anomaly formation associated with the March–May heavy rainfall events in Tanzania

Mafuru

Tan²

2019

Intl Journal of Climatology

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This work aims at detecting to what extent the El Niño Southern Oscillation (ENSO) modulation influences the upper warm temperature anomaly (UWTA) formation in Tanzania during March to May (MAM) season of 1980–2010. The UWTA has known to influence heavy rainfall events through enhanced vertical uplift and deepening surface low pressure. The study is thus critical towards improved early warning system through a better understanding of the mechanisms in the climate system responsible for the above average rainfall. The empirical orthogonal function analysis in this study, revealed the dominant interannual variability mode of the UWTA to be concentrated over the study region. The interannual variability of ENSO and the UWTA shows a moderate relationship during MAM (r = .5328) while a robust association (r = .7905) exists during the previous September to November (SON). Thus, the anomalous sea surface temperature anomaly (SSTA) of the central tropical Pacific (e.g., over Nino 3.4) leads 6 months before the UWTA of the study region and anomalous SSTA over the tropical Indian Ocean (TIO) peak up. Comparatively, the warm phase of ENSO during SON and December to February (DJF) is in phase relationship with the strengthened ascending branch of the Walker circulation over the warm TIO. Further analysis demonstrates that in SON the rising limb of the Walker circulation is the dominant source of uplift and convection enhancement over the warm TIO and later transports warm and moist air (i.e., diabatic heating) aloft for the UWTA formation during SON and DJF. Meanwhile, the Hadley circulation (HC) induced by the SSTA associated with ENSO exhibits the symmetric mode during SON and asymmetric mode in MAM. The asymmetric mode of the HC plays its role in transporting the warm and moist air from the warm TIO towards the study area for the UWTA formation during MAM.

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Assessing Prone Areas to Heavy Rainfall and the Impaction of the Upper Warm Temperature Anomaly during March–May Rainfall Season in Tanzania

Cited by 27 publications

References 48 publications

Understanding the Evolution and Socio-Economic Impacts of the Extreme Rainfall Events in March-May 2017 to 2020 in East Africa

Understanding the Evolution and Socio-Economic Impacts of the Extreme Rainfall Events in March-May 2017 to 2020 in East Africa

Inter-annual variability of March to May rainfall over Tanzania and its association with atmospheric circulation anomalies

The influence of ENSO on the upper warm temperature anomaly formation associated with the March–May heavy rainfall events in Tanzania

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