The central focus of the Aerosol-Climate Interactions research group in the Atmospheric and Oceanic Sciences Department at UCLA is to understand and quantify interactions between suspended aerosols (particles suspended in the atmosphere) and the climate system. This research is critical for at least two reasons. First, the climate impact of aerosols constitutes one of the main uncertainties in our understanding of both past and future climate changes. So a better understanding of aerosol effects on climate is critical for more accurate predictions of future climate changes. Accurate predictions of expected climate impacts are critical for society to both mitigate climate changes and to adapt to them and have an estimated economic value of many trillions of dollars. Second, the deliberate manipulation of interactions of aerosols with radiation and/or clouds can cool the planet and temporarily reduce global warming, possibly reducing some of the worst effects of climate change while society drives down emissions of greenhouse gases. There is much discussion over the risks, unintended consequences, and benefits of such techniques, known as geoengineering or climate intervention, and general agreement that these require much more research.
Within the broad field of aerosol-climate interactions, most of our group’s work focuses on desert dust aerosols, which are the constituent particles of dust storms, and account for about two thirds of atmospheric aerosol mass. The Aerosol-Climate Interactions group is interested in answering fundamental questions like: Does dust warm or cool the climate, and by how much? By how much has dust increased since pre-industrial times? Has this increase in dust enhanced or opposed anthropogenic climate change, and by how much? Will future climate-induced changes in desert dust oppose or enhance anthropogenic climate change? How much can we reduce the uncertainty on the all-important climate sensitivity by determining the perturbation of the Earth’s energy balance produced by dust? What are the relative roles in cirrus cloud formation of nucleation of ice crystals by dust and other aerosols (“heterogenous nucleation”) versus freezing of tiny droplets (“homogeneous nucleation”)? Can seeding of cirrus clouds by ice nucleating particles such as dust be used to temporarily offset global warming while society ramps reduces emissions of greenhouse gases?
In order to answer these fundamental questions of the effects of dust and other aerosols on the climate system, our group uses a number of tools, which include developing and using “simple” first-principles numerical models that run on desktop computers, large-scale climate models that require supercomputers, and careful analysis of in situ, satellite, and climate model data. Our group’s research is discussed in more detail here.
The Aerosol-Climate Interactions research group is headed by professor Jasper Kok, and funded by the National Science Foundation, NASA, and the Army Research Office.