DEVELOPMENT AND APPLICATION OF DROUGHT FORECASTING MODELS FOR NIGERIA SUDANO SAHELIAN REGION
DEVELOPMENT AND APPLICATION OF DROUGHT FORECASTING MODELS FOR NIGERIA SUDANO SAHELIAN REGION
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Date
2014-09
Authors
ADEOGUN, Babatunde Korode
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Abstract
Drought is a creeping natural phenomenon affecting the arid and semi arid regions,
including Nigerian Sudano-Sahelian Region. This research investigated droughts in Nigeria
Sudano-Sahelian Region and developed forecasting models for drought monitoring and
management in the region using well analysed meteorological data and imageries. The
meteorological data consists of temperature and rainfall data, both from 1979 to 2008,
collected from Nigeria Meteorological Organisation (NIMET), Oshodi, Lagos. The
Imageries consist of Normalized Difference Vegetation Index (NDVI) spanning 1981 to
2011, obtained from National Aeronautics and Space Administration (NASA) and SPOT –
Vegetation Programme of Vision on Technology (VITO), websites. Standardized
Precipitation Index (SPI) at different time scales were extracted from the rainfall record and
compared to determine the most suitable one for real time and early warning tool for
drought forecasting and, it was discovered that SPI_1 reflected nearly all droughts from
near normal condition to very severe dry condition. As a result, SPI_1 was chosen for
modelling but, it was compared with monthly NDVI anomaly to select the better one. The
results indicated that drought episodes detected by NDVI anomaly lagged some months
behind the corresponding ones identified by SPI_1. Hence SPI_1 was modelled, based on
Auto Regressive Moving Average/Seasonal Auto Regressive Moving Average
(ARIMA/SARIMA), to simulate drought occurrence at each station. Multiplicative
SARIMA model found suitable for SPI_1 forecasting at Sokoto, Nguru, Potiskum, Kano
and Gusau Stations was (011)x(011)12 while SARIMA model (1,1,1)x(1,1,1)12 was found
suitable for SPI_1 forecasting in Katsina and Maiduguri Stations. The multiplicative
SARIMA temperature models developed for Sokoto, Nguru, Potiskum, Kano and Gusau
Stations was SARIMA (2,1,1)x(2,1,1)12 while SARIMA (3,1,1)x(3,1,1)12 was found most
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suitable for Katsina and Maiduguri Stations. Drought analysis in the region showed that the
region had been exposed to droughts of different severity and magnitudes although, the
level of risk varies from one location to another. The region had been classified into high
drought risk zone consisting of Sokoto, Katsina, Damaturu and Nguru Stations, both in
Yobe, and Maiduguri. Moderate risk zone included Guzau, Kano and Dutse while parts of
Bauchi and Gombe States were identified as low risk zone. A drought management plan
was proposed for the study area based on the developed forecasting models. The plan has
three phases of drought emergence watch, warning and emergency.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF
POSTGRUADUATE STUDIES, AHMADU BELLO
UNIVERSITY, ZARIA
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE
AWARD
OF
DOCTOR OF PHILOSOPHY DEGREE IN WATER RESOURCES
AND ENVIRONMENTAL ENGINEERING
DEPARTMENT OF WATER RESOURCES AND ENVIRONMENTAL
ENGINEERING, FACULTY OF ENGINEERING,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
SEPTEMBER, 2014.
Keywords
DEVELOPMENT, DROUGHT, FORECASTING MODELS, NIGERIA, SUDANO SAHELIAN REGION