B. Ostendorf, MODELING THE INFLUENCE OF HYDROLOGICAL PROCESSES ON SPATIAL AND TEMPORAL PATTERNS OF CO2 SOIL EFFLUX FROM AN ARCTIC TUNDRA CATCHMENT, Arctic and alpine research, 28(3), 1996, pp. 318-327
Spatial and temporal patterns of CO? efflux from arctic tundra soils a
re examined with three, linked simulation models at a 2.2-km(2) catchm
ent. The model complex runs on a 2020 m grid and a temporal resolutio
n of 1 h over one growing season. TOPMODEL is used to predict the dyna
mics of the water balance and spatial pattern of water table. A canopy
model (GAS-FLUX) is used to predict moss and vascular plant transpira
tion rates. Soil respiration is computed from an empirical regression
model incorporating the effects of soil temperature and depth to the w
ater table. Soil efflux in the riparian zones of 60 g C m(-2) compares
tn 119 g C in the hillslopes indicating large spatial differences. An
increase of air temperature and solar radiation or a decrease of prec
ipitation increase soil respiration, The results indicate a tight conn
ection between water and carbon cycles at the catchment scale. Keeping
all other conditions constant, a seasonal increase of transpiration r
ates by 10% increases soil respiration by 5% or 4.6 g C m(-2). Data de
ficiencies and suggestions for future modeling are discussed.