Understanding linkages between global climate indices and terrestrial water storage changes over Africa using GRACE products

Abstract

Africa, a continent endowed with huge water resources that sustain its agricultural activities is increasingly coming under threat from impacts of climate extremes (droughts and floods), which puts the very precious water resource into jeopardy. Understanding the relationship between climate variability and water storage over the continent, therefore, is paramount in order to inform future water management strategies. This study employs Gravity Recovery And Climate Experiment (GRACE) satellite data and the higher order (fourth order cumulant) statistical independent component analysis (ICA) method to study the relationship between terrestrial water storage (TWS) changes and five global climate-teleconnection indices; El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Madden-Julian Oscillation (MJO), Quasi-Biennial Oscillation (QBO) and the Indian Ocean Dipole (IOD) over Africa for the period 2003-2014. Pearson correlation analysis is applied to extract the connections between these climate indices (CIs) and TWS, from which some known strong CI-rainfall relationships (e.g., over equatorial eastern Africa) are found. Results indicate unique linear-relationships and regions that exhibit strong linkages between CIs and TWS. Moreover, unique regions having strong CI-TWS connections that are completely different from the typical ENSO-rainfall connections over eastern and southern Africa are also identified. Furthermore, the results indicate that the first dominant independent components (IC) of the CIs are linked to NAO, and are characterized by significant reductions of TWS over southern Africa. The second dominant ICs are associated with IOD and are characterized by significant increases in TWS over equatorial eastern Africa, while the combined ENSO and MJO are apparently linked to the third ICs, which are also associated with significant increase in TWS changes over both southern Africa, as well as equatorial eastern Africa.

Understanding the global hydrological droughts of 2003–2016 and their relationships with teleconnections

“…This is done for the period of 2003-2016, from which we derive hot spots, where teleconnections appear strongly related to droughts. This investigation, therefore, extends previous efforts that study the relationships between teleconnections and water storage changes (e.g., Garćia-Garćia et al, 2011;Philips et al, 2012;Anyah et al, 2018;Eicker et al, 2016;Ni et al, 2018).…”

Evolutionary drought patterns over the Sahel and their teleconnections with low frequency climate oscillations

“…While the interest of relevant stakeholders in climate change is on the rise because of the need to address challenges related to water security and economic growth, the debate on the continued influence of atmospheric circulation features, warming of the tropical oceans, and indices of climate variability on hydro-meteorological processes is ongoing (e.g., 8,65,63,5,75,58,6,23,74). The catalogue of devastating impacts, including crop failure, loss of freshwater stocks, low gross domestic product (GDP), food insecurity, and loss of national income due to extreme droughts have been highlighted in some reports (see, e.g., 89,52,66,83,92,16,92,53,82,14).…”

Piezometric Behavior in the Amazonian Lateritic Plateaus: Implications of Climate Changes to the Recharge of the Alter do Chão Aquifer System

“…In Africa, Anyah, R. O. et al [11] dealt with the relationship between climate change and storage of water resources, which can be either linear or nonlinear, depending on the particularities of hydroclimatologic features, hydrological subsurface processes and land use activities. Hirata, R. et al [3] argue that, despite many forecasts pointing out to an increasing rainfall, the distribution patterns are going to be more irregular.…”