Environmental Sciences Division Steve Lindberg Recent Research Projects

Atmospheric Deposition to Mountainous Terrain:  Scaling-up to the Landscape*

Despite over two-decades of acid deposition research, measuring total deposition to complex terrain has not been possible. This study is developing a new modeling approach for scaling point measurements of atmospheric deposition to whole landscapes. Deposition of a variety of airborne constituents shows a predictable response to major landscape features that can be quantified in the field. These response functions can then be used to predict deposition patterns and relative rates of input of the chemicals of interest. During 1999-2002, we are quantifying these response functions across the landscapes of two National Parks, chosen for their potential air pollutant impacts and terrain features that severely restrict where routine flux monitoring can be done. Sulfate fluxes in throughfall (Figure 1) and lead in surface soils (Figure 2) are used to characterize the deposition/terrain response fields. The approaches have been shown to be excellent tracers of the primary deposition processes, and each addresses a time scale critical to the modeling approach. These response functions--indicating the enhancement of deposition in areas of interest relative to routine monitoring locations--are used in a GIS to scale up from the monitoring locations to the entire landscape, based on the spatial distribution of the primary controlling landscape features. The modeling approach is generic, allowing for application to other regions, and to a variety of airborne materials. Preliminary results show that vegetation type and--for montane regions--elevation, are the landscape features that have the greatest influence on fluxes.