The Feasibility of Reconstructing Hydroclimate over West Africa using
Tree-Ring Chronologies in the Mediterranean Region
Abstract
Dendrochronology in West Africa has not yet been developed despite
encouraging reports suggesting the potential for long tree-ring
reconstructions of hydroclimate in the tropics. This paper shows that
even in the absence of local tree chronologies, it is possible to
reconstruct the hydroclimate of a region using remote tree-rings. We
present the West Sub-Saharan Drought Atlas (WSDA), a new paleoclimatic
reconstruction of West African hydroclimate based on tree-ring
chronologies from the Mediterranean Region, made possible by the
teleconnected climate relationship between the West African Monsoon and
Mediterranean Sea surface temperatures. The WSDA is a one-half degree
gridded reconstruction of summer Palmer Drought Severity indices from
1500–2018 CE, produced using ensemble point-by-point regression.
Calibration and verification statistics of the WSDA indicate that it has
significant skill over most of its domain. The three leading modes of
hydroclimate variability in West Africa are accurately reproduced by the
WSDA, demonstrating strong skill compared to regional instrumental
precipitation and drought indices. The WSDA can be used to study the
hydroclimate of West Africa outside the limit of the longest observed
record and for integration and comparison with other proxy and
archaeological data. It is also an essential first step toward
developing and using local tree-ring chronologies to reconstruct West
Africa’s hydroclimate.