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On the Role of Dust‐Climate Feedbacks During the Mid‐Holocene
Author(s) -
Hopcroft Peter O.,
Valdes Paul J.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl080483
Subject(s) - holocene , precipitation , environmental science , atmospheric sciences , climatology , climate model , climate change , general circulation model , radius , climate state , mineral dust , range (aeronautics) , aerosol , geology , global warming , meteorology , physics , effects of global warming , materials science , oceanography , computer security , computer science , composite material
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.