Research Highlights for Climate Processes

During 28-30 June 2017, the RECAP project hosted an expert workshop on aerosol-precipitation interactions in Oxford, under the umbrella of the new GEWEX Aerosol Precipitation (GAP) initiative co-chaired by Sue van den Heever and Philip Stier.

Philip has just been awarded an 2016 ERC Consolidator grant to constRain the EffeCts of Aerosols on Precipitation (RECAP). This five year research programme will systematically constrain aerosol effects on precipitation across scales, combining process-based with energetic approaches.

This work builds on our earlier ERC Starting grant ACCLAIM with focus on aerosols effects on convective clouds and climate.

13-15 April 2016
Oriel College, Oxford

We will host the 2016 workshop of the international Aerosols, Clouds Precipitation and Climate initiative at Oriel College, University of Oxford.

The Aerosols, Clouds, Precipitation and Climate (ACPC) initiative by iLEAPS and GEWEX has been established to facilitate and enable international and interdisciplinary research on the interactions between aerosols, clouds and precipitation in the climate system.

We will contribute to the UK measurement campaign CLoud-Aerosol-Radiation Interactions and Forcing (CLARIFY-2016), targeting the interaction of aerosols from wildfires with the extensive stratocumulus cloud deck off the coast of southern Africa:

All satellite-based estimates of aerosol cloud interactions used in IPCC's 5th assessment report rely on one assumption: that aerosol radiative properties from passive satellite remote sensing can serve as proxy for cloud condensation nuclei.

In this work, Philip uses the fully self-consistent global aerosol model ECHAM-HAM to show that this widely used assumption is violated for a large fraction of the Earth.

It is often implicitly assumed that over suitably long periods the mean of observations and models should be comparable, even if they have different temporal sampling. We have assessed the errors incurred due to ignoring temporal sampling and show they are of similar magnitude as (but smaller than) actual model errors (20–60%).

Duncan Watson-Parris joined us recently to work on novel observational constraints for aerosol climate models.

Duncan is also the lead developer of our Community Intercomparison Suite, an open source software tool for easy analysis, intercomparison and visualisation of complex datasets (models, satellites, in-situ) in Earth System Science.