Investigating spatial variability of aerosol and cloud nuclei in mountainous terrain

Atmospheric aerosols can have large impacts on clouds and precipitation by serving as cloud condensation nuclei (CCN) and ice nucleating particles (INP). Understanding the impacts of these particles on clouds is critical to improving our understanding of and ability to forecast precipitation and its resulting impacts on the hydrologic cycle. This predictive ability is especially important in the western United States, and other regions globally, where mountain-impacted precipitation is critical to local and downstream water supplies. Our goal is to better understand the physical processes, focusing on aerosol-cloud interactions, that occur in mountain regions by deploying a novel network of miniaturized instrumentation in the East River Watershed near Crested Butte, Colorado in the vicinity of the DOE funded, Surface Atmosphere Integrated Field Laboratory (SAIL). As part of SAIL, the DOE has deployed one of their ARM Mobile Facilities (AMF2) and the Aerosol Observing System (AOS) which incorporate an extensive suite of aerosol, cloud and meteorological measurements. However, these measurements are confined to a limited spatial domain which could miss important regions of aerosol-cloud interactions, especially in this region of complex topography. To expand on the SAIL aerosol measurements, we are setting up a network of six aerosol measurement nodes spanning both the horizontal and vertical extent of the SAIL domain. Each microphysics measurement node includes a small optical particle counter (POPS), a novel, miniature CCN counter (CloudPuck), and a filter sampler (TRAPS) for subsequent INP analysis. We will collaborate with several SAIL investigators to better understand the impacts of aerosols on clouds during the study by linking our network observations with complementary in situ measurements, remotely sensed cloud and aerosol properties, and modeling efforts. Our science goals are to (1) examine how vertical variations in aerosols and cloud nuclei affect clouds, (2) identify factors driving temporal and spatial variability in aerosols and cloud nuclei in mountainous terrain, and (3) examine effectiveness of a network-based approach to understanding complex aerosol-cloud interactions as this is the first study of its kind to deploy this number and type of sensors in a relatively small study area.