On the role of dust‐climate feedbacks during the mid‐Holocene
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Colleges, School and Institutes
A reduction in dust over North Africa during the mid-Holocene “Green Sahara” period could have amplified precipitation, helping reconcile climate model simulations with paleo-precipitation reconstructions. Here we test this using general circulation model simulations including interactive dust. We calculate a dust-precipitation amplification factor using three different dust configurations to evaluate the sensitivity to dust optical properties and particle size range. The resultant amplification ranges from −20% to 50%. With more absorbing dust properties, there is a large negative net radiative effect and hence a larger impact on the hydrological cycle. With the inclusion of particles greater than 1 μm in radius, the precipitation amplification is reversed. Based on the simulations which best match observed Saharan dust properties, we conclude that there was a limited enhancement of precipitation due to reduced dust during the mid-Holocene, meaning other aspects of the climate system should be the focus of future research.
|Number of pages||10|
|Journal||Geophysical Research Letters|
|Early online date||27 Dec 2018|
|Publication status||Published - 16 Feb 2019|