Publication Date:
2024-05-21
Description:
The increase in summer monsoon precipitation over western Africa during the last interglacial (LIG) relative to
the pre-industrial (PI) is well documented, but it is uncertain whether this increase is due to larger rainfall rate
alone, an extension of the summer monsoon season or a combination of the two. Due to different orbital config-
uration, the boreal summer of the LIG was warmer but shorter than the PI, potentially influencing the summer
monsoon duration. In this study, we employ a newly developed isotope-enabled climate model, AWI-ESM-wiso
to investigate the intensity and length of the West African Summer Monsoon (WASM) for both LIG and PI time
periods. Our model results indicate that, despite an intensification in summer insolation and an enhanced hydro-logical cycle, WASM season in the LIG is 9 days shorter compared to the PI. During the LIG, increased insolation in late spring and early summer strengthens the Saharan heat low (SHL) and its associated sub-systems, facilitating a faster accumulation of potential instability and an earlier WASM onset. However, a substantial earlier
withdrawal of the WASM is also detected, driven by an earlier southward shift of insolation maximum. More-
over, our findings are further supported by models participating in the 4th phase of the Paleoclimate Modelling
Intercomparison Project (PMIP4).
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
