Meeting in the middle: Bottom-up and top-down scaling approaches

TitleMeeting in the middle: Bottom-up and top-down scaling approaches
Publication TypeConference Paper
Year of Publication2002
AuthorsCoughenour M., Goslee S.C., Pielke R.
Conference Name17th Annual Symposium, US-International Association for Landscape Ecology
Date PublishedApril 23-25, 200
Conference LocationLincoln, NE
ARIS Log Number152501
AbstractMany ecologists measure ecosystem processes and characteristics over a small area and then extrapolate to a larger spatial extent (bottom-up scaling). Others use tools such as global circulation models to study processes over an extremely large region and then use those results at finer spatial scales (top-down scaling). Since most ecological management takes place at the landscape scale, it is essential to understand how both finer and coarser processes function at that level. We discuss applications of bottom-up and top-down scaling and illustrate general recommendations and specific pitfalls, emphasizing the similarities between the two approaches. Examples are given of the use and misuse of downscaling large-scale atmospheric data for use as input to vegetation and biogeochemical models. Top-down scaling is also used to apply data from global vegetation models to scales at which management decisions are made. Bottom-up scaling is required to aggregate land surface heterogeneities for use in describing fluxes into and out of the atmosphere and for extrapolating vegetation data from sampling plots to larger areas. Both scaling up and scaling down are needed to understand ecosystem functions at the landscape scale so that we can make accurate predictions and effective management decisions.