Observed trends and projections of temperature and precipitation in the Olifants River Catchment in South Africa
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Date
Authors
Adeola, Abiodun Morakinyo
Kruger, Andries C.
Makgoale, Thabo Elias
Botai, Joel Ongego
Journal Title
Journal ISSN
Volume Title
Publisher
Public Library of Science
Abstract
Among the projected effects of climate change, water resources are at the center of the
matrix. Certainly, the southern African climate is changing, consequently, localized studies
are needed to determine the magnitude of anticipated changes for effective adaptation. Utilizing historical observation data over the Olifants River Catchment, we examined trends in
temperature and rainfall for the period 1976–2019. In addition, future climate change projections under the RCP 4.5 and RCP 8.5 scenarios for two time periods of 2036–2065 (near
future) and 2066–2095 (far future) were analysed using an ensemble of eight regional climate model (RCA4) simulations of the CORDEX Africa initiative. A modified Mann-Kendall
test was used to determine trends and the statistical significance of annual and seasonal
rainfall and temperature. The characteristics of extreme dry conditions were assessed by
computing the Standardized Precipitation Index (SPI). The results suggest that the catchment has witnessed an increase in temperatures and an overall decline in rainfall, although
no significant changes have been detected in the distribution of rainfall over time. Furthermore, the surface temperature is expected to rise significantly, continuing a trend already
evident in historical developments. The results further indicate that the minimum temperatures over the Catchment are getting warmer than the maximum temperatures. Seasonally,
the minimum temperature warms more frequently in the summer season from December to
February (DJF) and the spring season from September to November (SON) than in the winter season from June to August (JJA) and in the autumn season from March to May (MAM).
The results of the SPI affirm the persistent drought conditions over the Catchment. In the
context of the current global warming, this study provides an insight into the changing characteristics of temperatures and rainfall in a local context. The information in this study can
provide policymakers with useful information to help them make informed decisions regarding the Olifants River Catchment and its resources.
Description
DATA AVAILABILITY STATEMENT : The data process is done using R Software which includes several packages for mapping NetCDF data. Sample data and scripts used for this study are made available on Open Science Framework at https://osf.io/8rhn2 and https://osf.io/3d9j4.
Keywords
Climate change, Seasons, Rain, Drought, Spring, Summer, Winter, South Africa (SA)
Sustainable Development Goals
Citation
Adeola, A.M., Kruger, A., Elias Makgoale, T. & Botai, J.O. (2022) Observed trends and
projections of temperature and precipitation in the
Olifants River Catchment in South Africa. PLoS
One 17(8): e0271974. https://doi.org/10.1371/journal.pone.0271974.