TITLE:
Climatic Indices’ Analysis on Extreme Precipitation for Tanzania Synoptic Stations
AUTHORS:
Daudi Mikidadi Ndabagenga, Jinhua Yu, Justus Renatus Mbawala, Charles Yusuph Ntigwaza, Ali Said Juma
KEYWORDS:
Extreme Precipitation, Climatic Indices, Tanzania, Mann-Kendall, ETCCDI, Trend
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.12,
December
29,
2023
ABSTRACT: Like other countries in East Africa, Tanzania has been affected by extreme
precipitation incidences both socially and economically. Determining the trend
and variability features of extreme precipitation in the country is crucial.
This study used data from 28 meteorological stations for 1981-2020 period to
give an annual and seasonal analysis of the patterns of 10 ETCCDI’s extreme
precipitation indices over the regions. At annual scale, the results showed
that increasing trends had high frequency percentage than the decreasing ones,
collecting about 76% in total. The decreasing trend was approximately 24%, and
most of the stations with increasing percentage in trend are concentrated in
Northern coast, Central, West, North-eastern highlands and Lake Victoria Basin.
Most of the stations depicted negative trend are concentrated over Southern
region. This highlights that extreme precipitation events have increased over
the country for the period 1981-2020. At seasonal scale, during October to
December (OND); the patterns of extreme precipitation climatic indices except
R99p, showed positive significant increasing trend over Lake Victoria Basin and
some Western parts of the country. In general, spatial patterns indicate
decrease of precipitation over most parts of the country during OND. The
seasonal average time series depicted non-significant positive trend during
March to April (MAM) season, except for Consecutive Wet Days (CWD) which showed
non-significant decreasing trend. Over the highest mountain in Africa, Kilimanjaro;
the study has revealed significant decrease in Annual total-wet Precipitation
(PRCPTOT), the number of heavy (very heavy) days of precipitation R10 mm (R20 mm) and Consecutive Wet
Days (CWD) during MAM season. While the maximum one-day precipitation amount
(RX1 day)
was observed to decrease significantly over the Mountain during OND season. The
result is very important in risk assessment and preparedness perspective in
planning climate change mitigation and adaptations for different sectors like
Tourism, Agriculture, Water and Energy.