Publication Date:
2023-12-14
Description:
Southern Africa, with its vast arid to semiarid areas, is considered vulnerable to precipitation changes and amplifying weather extremes. However, during the last 100 ka, huge lakes existed in the currently dry central Kalahari. It has been suggested that these lakes could have existed due to altered atmospheric circulation pattern, leading to an increase in precipitation or to changes in the annual precipitation distribution. Past climate changes are recorded in paleo‐archives, yet, for a proper interpretation of paleo‐records, for example, from sedimentological archives or fossils, it is essential to put them in a context with recent observations. This study’s objective is, therefore, to analyze spatially differing annual precipitation distributions at multiple locations in southern Africa with respect to their stable water isotope composition, moisture transport pathways, and sources. Five different precipitation distributions are identified by end‐member modeling and respective rainfall zones are inferred, which differ significantly in their isotopic compositions. By calculating backward trajectories, different moisture source regions are identified for the rainfall zones and linked to typical circulation patterns. Our results furthermore show the importance of the seasonality, the amount effect, and the traveled distance of the moisture for the general isotopic composition over the entire southern Africa. The identified pattern and relationships can be useful in the evaluation of isotope‐enabled climate models for the region and are potentially of major importance for the interpretation of stable water isotope composition in paleo‐records in future research.
Description:
Key Points:
We identified five different annual precipitation distributions in southern Africa that cluster in space and define rainfall zones.
Lagrangian source diagnostic shows that the rainfall zones have notably different moisture sources.
The isotopic composition differs significantly between rainfall zones.
Description:
Deutsche Forschungsgemeinschaft
http://dx.doi.org/10.13039/501100001659
Description:
https://nucleus.iaea.org/wiser
Description:
https://doi.pangaea.de/10.1594/PANGAEA.944811
Description:
https://doi.org/10.24381/cds.bd0915c6
Description:
http://iacweb.ethz.ch/staff/sprenger/lagranto/
Description:
https://forobs.jrc.ec.europa.eu/products/glc2000/products.php
Description:
https://doi.org/10.6084/m9.figshare.7504448.v3
Description:
https://doi.org/10.5066/F7J38R2N
Description:
https://cran.r-project.org/bin/windows/base/old/
Description:
https://cran.r-project.org/web/packages/EMMAgeo/index.html
Description:
https://cran.r-project.org/web/packages/party/index.html
Keywords:
ddc:551.5
;
Lagrangian moisture source diagnostic
;
stable water isotopes
;
precipitation end‐member
;
random forest
;
annual rainfall distribution
;
moisture pathways
Language:
English
Type:
doc-type:article
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