TITLE:
Spatio-Temporal Variability of Rainfall and Temperature and Their Effects on Pasture Variability over East Africa: Implication on the Cattle Grazing Areas
AUTHORS:
Natiko Peter, Wang Wen, Nyasulu Matthews, Raharivelo Sitraka Ny Aina, Alupot Donnata
KEYWORDS:
NDVI, Climatic Parameters, EOF, Pasture, East Africa
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.12 No.3,
March
21,
2024
ABSTRACT: Understanding the
spatiotemporal variability of climatic parameters and their effects on pasture
variability is vital for pasture management interventions over East Africa. The
present study aims to assess the spatial-temporal variability of rainfall,
temperature and Normalized Difference Vegetation Index (NDVI) (which is being used to assess pasture quality and
productivity) over the region, between the period of 1982 and 2019. This study
used annual mean values for rainfall, temperature and NDVI which were
calculated for the period mentioned above. NDVI was derived from National
Oceanic and Atmospheric Administration (NOAA) Global Area Cover (GAC)
(NOAA-07-GAC) data. The rainfall data was acquired from the Climate
Hazards Group Infrared Precipitation with Station (CHIRPS) while temperature is
ERA5 reanalysis data sourced from the European Centre for Medium-Range Weather
Forecasts (ECMWF). The study utilized the empirical orthogonal function (EOF)
to identify patterns and dominant relationships between the climate variables.
The correlation was calculated between rainfall, temperature and NDVI to assess
the relationship among them. A non-parametric Mann-Kendall trends test was used
to determine whether annual precipitation, temperature and NDVI had
statistically increasing or decreasing trend. Results revealed a positive
correlation between rainfall and NDVI while a negative correlation between NDVI
and temperature. Positive correlation between rainfall and NDVI indicates that
pasture health (quality and productivity), will improve accordingly. A negative
correlation between temperature and NDVI indicates that pasture health will
decrease with increase in temperature while improving with decreasing
temperature. Outcome from this study suggests that changes in climatic
variables influence the distribution of pasture in East Africa’s cattle grazing
areas. The study hence recommends prioritisation of climatic
(weather) information during pasture management over East Africa.