Effects of climate change on evapotranspiration over the Okavango Delta water resources

Moses, Oliver; Hambira, Wame L.

doi:10.1016/j.pce.2018.03.011

Cited by 31 publications

(8 citation statements)

References 26 publications

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“…The Okavango Delta, which is a world heritage and Ramsar site, has extremely high biodiversity supporting economically vital ecotourism (Mbaiwa, 2004, 2015). Climate variability and change also impacts water security and flood recession farming on the outskirts of the Delta (Murray‐Hudson et al, 2006; Mbaiwa, 2015; Moses and Hambira, 2018).…”

Section: Introductionmentioning

confidence: 99%

Relationships between NDVI, river discharge and climate in the Okavango River Basin region

Moses

Blamey

Reason

2021

Intl Journal of Climatology

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The Okavango River Basin (ORB) is a highly sensitive and biodiverse region in southern Africa whose climate, vegetation and river discharge characteristics are not well understood. This study investigated relationships between rainfall, temperature, Normalized Difference Vegetation Index (NDVI) and river discharge over the region as well as their trends and interannual variability. It is found that spatial patterns of NDVI are closely related to those of rainfall, but less so with temperature at monthly and seasonal time scales. The relationships between NDVI and rainfall/temperature differ north of 18.9°S where rainfall is higher than to its south. Typically, there are lags of 1–2‐months between NDVI and either rainfall or temperature. Also, there are large areas across the region that show significant warming trends in all seasons as well as wetting (mainly in the north). This increasing trend in surface temperature may act to worsen the impacts of extreme events such as severe drought and fire in the region. There is also pronounced interannual variability with significant correlations found with El Niño‐Southern Oscillation (ENSO), the subtropical South Indian Ocean Dipole and the Botswana High for rainfall and temperature, and for NDVI with ENSO. For the Southern Annular Mode, significant correlations were found with rainfall and temperature only in December and April. On longer time scales, focus was also placed on the wet 2006–2013 period relative to much drier 1999–2005 epoch for October–December. The wetter conditions during 2006–2013 appear related to La Niña Modoki conditions and warmer sea surface temperature near Angola as well as regional circulation differences.

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Section: Introductionmentioning

confidence: 99%

Relationships between NDVI, river discharge and climate in the Okavango River Basin region

Moses

Blamey

Reason

2021

Intl Journal of Climatology

Self Cite

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“…Evapotranspiration (ET) as an important hydrological parameter is affected by weather variables such as temperature, relative humidity, wind speed, solar radiation, and so on. Subsequently, climate change can influence ET as confirmed by the previous investigations [23][24][25]. Harmsen et al [26] evaluated the effect of climate change on the reference ET in a study in 2009 and he found decreasing crop yields in Puerto Rico under different scenarios.…”

Section: Introductionmentioning

confidence: 76%

Investigation into the Effects of Climate Change on Reference Evapotranspiration Using the HadCM3 and LARS-WG

Bayatvarkeshi

Zhang

Fasihi

et al. 2020

Water

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This study evaluates the effect of climate change on reference evapotranspiration (ET0), which is one of the most important variables in water resources management and irrigation scheduling. For this purpose, daily weather data of 30 Iranian weather stations from 1981 and 2010 were used. The HadCM3 statistical model was applied to report the output subscale of LARS-WG and to predict the weather information by A1B, A2, and B1 scenarios in three periods: 2011–2045, 2046–2079, and 2080–2113. The ET0 values were estimated by the Ref-ET software. The results indicated that the ET0 will rise from 2011 to 2113 approximately in all stations under three scenarios. The ET0 changes percentages in the A1B scenario during three periods from 2011 to 2113 were found to be 0.98%, 5.18%, and 12.17% compared to base period, respectively, while for the B1 scenario, they were calculated as 0.67%, 4.07%, and 6.61% and for the A2 scenario, they were observed as 0.59%, 5.35%, and 9.38%, respectively. Thus, the highest increase of the ET0 will happen from 2080 to 2113 under the A1B scenario; however, the lowest will occur between 2046 and 2079 under the B1 scenario. Furthermore, the assessment of uncertainty in the ET0 calculated by the different scenarios showed that the ET0 predicted under the A2 scenario was more reliable than the others. The spatial distribution of the ET0 showed that the highest ET0 amount in all scenarios belonged to the southeast and the west of the studied area. The most noticeable point of the results was that the ET0 differs from one scenario to another and from a period to another.

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“…Their dependency on water means that anthropogenic threats of climate change and water development threaten hippo populations considerably (Milzow et al., 2010; Milzow, Kgotlhang, Kinzelbach, et al., 2009; Murray‐Hudson et al., 2006). Climate change models predict increases in temperature and evaporation and decreases in rainfall over southern Africa, increasing drought intensity and frequency (Moses & Hambira, 2018; Niang et al., 2014). These climate change scenarios will reduce habitat for hippos in the Delta (Nuñez, 2017), as reduced local rainfall will limit grazing, and lower rainfall in Angola will lead to reduced inflow into the Delta, causing drying.…”

Section: Discussionmentioning

confidence: 99%

Temporal and spatial patterns of common hippopotamus populations in the Okavango Delta, Botswana

et al. 2021

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Conservation requires reliable estimates of a species' population and their spatial distribution. Knowledge of large‐scale habitat use and population trends in common hippopotamus (Hippopotamus amphibius; hereafter hippo) in wetland ecosystems is limited, with no studies of hippo populations in the Okavango Delta (the Delta), Botswana. We examined the drivers of long‐term trends and spatial patterns in the Delta's hippo population, using 13 years of aerial surveys (1996–2018) informing on the potential impacts of changes in inflow, flooding patterns and rainfall on hippo populations. We estimated temporal changes in hippo populations and relationships with rainfall and inflow. We also examined how spatially explicit hippo counts related to flood and surface water extent and vegetation class at different scales. The Delta's hippo population has increased, probably due to increasing long‐term rainfall and inflow, following a period of severe drought/low flooding. Hippos were positively associated with areas with high variation in flooding and negatively associated with broad‐scale surface water extent, indicating hippos avoided permanent swamps and main channels, probably due to water depth, lack of nearby grazing, and thick riparian vegetation. At a fine scale, hippos relied on large lagoons for daytime refuge. The most recent population estimate indicates that Botswana has the third highest hippo population in Africa, reflecting the importance of the Delta. Reductions in inflow and rainfall from climate change and water resource development would threaten these hippo populations by reducing grazing availability, lagoon sizes, and seasonal swamps. Ongoing monitoring of hippos should continue as they represent a good indicator for the entire floodplain ecosystem.

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Effects of climate change on evapotranspiration over the Okavango Delta water resources

Cited by 31 publications

References 26 publications

Relationships between NDVI, river discharge and climate in the Okavango River Basin region

Relationships between NDVI, river discharge and climate in the Okavango River Basin region

Investigation into the Effects of Climate Change on Reference Evapotranspiration Using the HadCM3 and LARS-WG

Temporal and spatial patterns of common hippopotamus populations in the Okavango Delta, Botswana

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