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Publication - Dr Peter Hopcroft

    On the Role of Dust-Climate Feedbacks During the Mid-Holocene

    Citation

    Hopcroft, PO & Valdes, PJ, 2019, ‘On the Role of Dust-Climate Feedbacks During the Mid-Holocene’. Geophysical Research Letters, vol 46., pp. 1612-1621

    Abstract

    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.

    Full details in the University publications repository