The Boreal Ecosystem–Atmosphere Study (BOREAS): An Overview and Early Results from the 1994 Field Year

Abstract

The Boreal Ecosystem Atmosphere Study (BOREAS) is a largescale international field experiment that has the goal of improving our understanding of the exchanges of radiative energy, heat, water, C02, and trace gases between the boreal forest and the lower atmosphere. An important objective of BOREAS is to collect the data needed to improve computer simulation models of the processes controlling these exchanges so that scientists can anticipate the effects of global change. From August 1993 through September 1994, a continuous set of monitoring measurements-meteorology, hydrology, and satellite remote sensing-were gathered overthe 1000 x 1000 km BOREAS study region that covers most of Saskatchewan and Manitoba, Canada. This monitoring program was punctuated by six campaigns that saw the deployment of some 300 scientists and aircrew into the field, supported by 11 research aircraft. The participants were drawn primarily from U.S. and Canadian agencies and universities, although there were also important contributions fjom France, the United Kingdom, and Russia. The field campaigns lasted for a total of 123 days and saw the compilation of a comprehensive surfaceatmosphere flux dataset supported by ecological, trace gas, hydrological, and remote sensing science observations. The surface-atmosphere fluxes of sensible heat, latent heat, C02, and momentum were measured using eddy correlation equipment mounted on a surface network of 10 towers complemented by four

Parameterization of shortwave radiation fluxes for nonuniform vegetation canopies in land surface models

“…Under these assumptions, the twostream approximation for radiative transfer within vegetation canopies is [Dickinson, 1983] XL [Ross, 1975], where XL--1 for horizontal leaves and XL =-1 for vertical leaves. The physical meaning of (1) and (2) is discussed in detail by Sellers [1985]. …”

Micrometeorological measurements of methane and nitrous oxide exchange above a boreal aspen forest

“…There is a rich understory comprising 60% hazelnut (Corylus cornuta) and 15% wild rose (Rosa woodsii). The soil is classified as an Orthic Gray Aluvisol, featuring a well to moderately well drained loam to clay loam till and an organic layer depth less than 8 cm [Sellers et al, 1994].…”

Snow ablation modeling at the stand scale in a boreal jack pine forest

“…Sellers et al, 1995a]. BOREAS investigators conducted intensive field studies between 1993 and 1996 in the boreal forest of central Saskatchewan and northern Manitoba, Canada.…”