Associate Professor
Climate, Atmospheric Science & Physical Oceanography

Evan Research Lab

Our lab studies a number of interesting processes in the atmosphere and at the Earth's surface, and how those processes are impacted by climate change. Below are the current research topics we are working on.

Dust storms and the Salton Sea

Just a hundred miles to the east of San Diego, one of the largest inland lakes in the Western US is drying up as a result of human activity. In order to understand how the shrinking of the Sea will impact future frequency and intensity of dust storms there we need to better understand the dynamics of dust outbreaks in this region. To address this need we have built and instrumented a research site that is providing continuous measurements of aerosols, the structure of the oundary layer, water vapor, and radaitive fluxes. We will be using this information to improve understanding of the underlying physics, and model estimates of regional dust activity.

Lab collaborator Robert Frouin waits for the sun photometer to "wake up" and start making measurements.

Radiative Forcing of dust and global climate

There is a large amount of uncertainty related to the magnitude of the dust direct radiative effect. In order to address these uncertainties--and help to evaluate the representation of dust in climate models--we are developing and testing new methods to observationally estimate the magnitude of the dust direct raditaive effect.

The impact of warming on mountain snowpack

As the planet warms snowpack in montane environments will diminish due to an increase in the fraction of precipitation that falls in the liquid form, and a reduction in the length of time during each year when air temperatures are below the freezing point. However, finding evidence of such effects in the observational recod can be challenging due to the influence of natural variability. We are developing new methods to evaluate existing records of mountain snowpack in order to develop and test theories about how this resource will be affected by continued warming.  

Dust and Atmospheric rivers

California receives the majority of its precipitation from a small number of wintertime storms containing high amounts of water vapor, so-called atmospheric rivers. A number of studies have shown that long-range transported dust from Asia and Africa can alter the amount of precipitation associated with these systems via the glaciation effect. However, observations of such impacts are very limited, and relatively little work has gone into improving our theoretical understanding of the relevant processes. We are approching this problem using satellite data, idealized numerical modeling, and soon rainwater sampling, in order to understand how often dust interacts with atmospheric rivers, and under what conditions dust may have a large role in shaping the resultant precipitation.