Controls on carbon and energy exchange by a black spruce–moss ecosystem: Testing the mathematical model <i>Ecosys</i> with data from the BOREAS Experiment

Grant, R. F.; Jarvis, P. G.; Massheder, J. M.; Hale, Sophie; Moncrieff, John; Rayment, Mark; Scott, Steve; Berry, J. A.

doi:10.1029/2000gb001306

Cited by 30 publications

(22 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ecosys was initialized with the soil properties of the Typic Aquiturbel and the plant properties of sedge (the same as those of grass in Grant et al ., 2001c but with more aerenchymous volume in the roots) and moss (the same as those of moss in Grant et al ., 2001a, 2001b; with litterfall partitioned more into hydrolysis‐resistant components than that of deciduous vegetation based on Hobbie et al ., 2000). The Arrhenius curve used for modelling the temperature sensitivities of CO 2 fixation in arctic plants was displaced downward by 6 °C from that used for temperate plants and soils based on Tiezen et al .…”

Section: Heterotrophic Respirationsupporting

confidence: 91%

“…Earlier projections of climate change effects on NEP in boreal forests by using ecosys indicated that rises in NPP and R h were coupled, so that ecosystem C stocks rose (Grant & Nalder, 2000; Grant et al ., 2001a,b). Ecosys was used in order to examine climate effects on NEP in an arctic coastal tundra by testing hourly model output for C and energy exchange under changing weather conditions with eddy correlation fluxes and soil temperatures measured in the NSF Arctic System Science (ARCSS) Land Atmosphere Ice Interactions (LAII) Flux Study at Barrow, Alaska.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modelling carbon balances of coastal arctic tundra under changing climate

Grant

Oechel

Ping

2002

Global Change Biology

View full text Add to dashboard Cite

Rising air temperatures are believed to be hastening heterotrophic respiration (Rh) in arctic tundra ecosystems, which could lead to substantial losses of soil carbon (C). In order to improve confidence in predicting the likelihood of such loss, the comprehensive ecosystem model ecosys was first tested with carbon dioxide (CO2) fluxes measured over a tundra soil in a growth chamber under various temperatures and soil‐water contents (θ). The model was then tested with CO2 and energy fluxes measured over a coastal arctic tundra near Barrow, Alaska, under a range of weather conditions during 1998–1999. A rise in growth chamber temperature from 7 to 15 °C caused large, but commensurate, rises in respiration and CO2 fixation, and so no significant effect on net CO2 exchange was modelled or measured. An increase in growth chamber θ from field capacity to saturation caused substantial reductions in respiration but not in CO2 fixation, and so an increase in net CO2 exchange was modelled and measured. Long daylengths over the coastal tundra at Barrow caused an almost continuous C sink to be modelled and measured during most of July (2–4 g C m−2 d−1), but shortening daylengths and declining air temperatures caused a C source to be modelled and measured by early September (∼1 g C m−2 d−1). At an annual time scale, the coastal tundra was modelled to be a small C sink (4 g C m−2 y−1) during 1998 when average air temperatures were 4 °C above normal, and a larger C sink (16 g C m−2 y−1) during 1999 when air temperatures were close to long‐term normals. During 100 years under rising atmospheric CO2 concentration (Ca), air temperature and precipitation driven by the IS92a emissions scenario, modelled Rh rose commensurately with net primary productivity (NPP) under both current and elevated rates of atmospheric nitrogen (N) deposition, so that changes in soil C remained small. However, methane (CH4) emissions were predicted to rise substantially in coastal tundra with IS92a‐driven climate change (from ∼20 to ∼40 g C m−2 y−1), causing a substantial increase in the emission of CO2 equivalents. If the rate of temperature increase hypothesized in the IS92a emissions scenario had been raised by 50%, substantial losses of soil C (∼1 kg C m−2) would have been modelled after 100 years, including additional emissions of CH4.

show abstract

Section: Heterotrophic Respirationsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Modelling carbon balances of coastal arctic tundra under changing climate

Grant

Oechel

Ping

2002

Global Change Biology

View full text Add to dashboard Cite

show abstract

“…The SK‐OBS site physical and biological properties are extensively documented [e.g., Grant et al ., ; Barr et al ., ; Bergeron et al ., ; Dunn et al ., ; Krishnan et al ., ]. Gaps in flux measurements caused by unfavorable conditions or equipment malfunction were filled using the Fluxnet‐Canada gap‐filling protocol described by Barr et al .…”

Section: Class‐ctem Overviewmentioning

confidence: 99%

Modeling the diurnal variability of respiratory fluxes in the Canadian Terrestrial Ecosystem Model (CTEM)

Badawy

Arora

Melton

et al. 2016

J Adv Model Earth Syst

View full text Add to dashboard Cite

The Canadian Terrestrial Ecosystem Model (CTEM) coupled to the Canadian Land Surface Scheme (CLASS) is a dynamic vegetation model that incorporates photosynthesis and respiration submodules among many other physiological processes of the terrestrial biosphere. While the photosynthesis and leaf respiration submodules of CTEM operate at a time step of 30 min, other respiratory fluxes are estimated at a daily time step using the daily-averaged values of canopy and soil temperature, and soil moisture content. Here we modify CTEM to be able to simulate the diurnal variation of ecosystem respiratory fluxes caused by the diurnal variation in the driving climate data. Simulating respiration at a 30 min time step changed the equilibrium states of primary carbon pools and fluxes. This required changes to some of the model's parameters in order to realistically simulate the equilibrium values of carbon pools and fluxes. The resulting estimated daily and annual carbon fluxes from the modified and original CTEM are similar with small relative differences. The similar annual cycles of daily values of primary CO 2 fluxes confirm that modeling the respiratory fluxes at a subdaily time step does not affect the annual cycles of these fluxes. We also demonstrate that the modified version of the model is able to simulate the diurnal cycle of net ecosystem exchange of CO 2 fluxes that are broadly comparable to observation-based estimates at two flux tower sites and exhibit realistic seasonal patterns. Limitations remain in the modeled diurnal patterns of primary landatmosphere CO 2 fluxes which will form the basis of further model improvements.

show abstract

“…Mean fine‐root biomass (<2 mm) to a depth of 40 cm is 3.3 ± 1.0 Mg dry matter ha −1 (average for 2003–2004) [ Kalyn and Van Rees , 2006]. The physical and biological properties of this site [ Grant et al , 2001] are shown in Table 1. The 30‐year mean annual air temperature and precipitation measured at a climate station located 80 km away (1934–1990, Waskesiu Lake, 53.6°N, 106.1°W) are 0.3°C and 456 mm, respectively.…”

Section: Experimental Data and Model Parameterizationmentioning

confidence: 99%

Daily heterotrophic respiration model considering the diurnal temperature variability in the soil

Chen

Huang

et al. 2009

J. Geophys. Res.

View full text Add to dashboard Cite

[1] In daily, monthly, and annual respiration models for regional and global applications, the diurnal variation of temperature is generally ignored. As the effect of temperature on respiration is nonlinear, this ignorance may cause considerable errors in respiration estimation, but these errors have not yet been systematically investigated. This is in fact a central issue in temporal scaling of ecosystem models which are often applied in time steps equal to or larger than a day. In this study, we develop an integrated daily heterotrophic respiration model, and demonstrate first theoretically the importance of considering the diurnal amplitude of soil temperature and the vertical soil carbon distribution pattern in daily respiration estimation using the daily mean temperature. Measurements of soil respiration with roots exclusion made in a mature black spruce site in Saskatchewan, Canada, in July-September 2004 are used to validate the model. Daily heterotrophic respiration rates were underestimated by up to 15%, with a mean value of 4.5%, when only the mean daily temperature was used. This underestimation occurred under the conditions that the diurnal temperature amplitude in the forest was less than 12°C and the vertical distribution of organic carbon in the top 15-30 cm was uniform. Based on the integrated daily model, this underestimation at the same site would be 38% if the amplitude increases to 20°C, and in soils with steep vertical carbon distributions with a 20°C diurnal amplitude, it can increase to 44%. The magnitude of this underestimation is theoretically proportional to [ln(Q 10 )] 2 . During the experimental period, the value of Q 10 for heterotrophic respiration was found to be 4.0-4.5. If Q 10 = 2.0, this underestimation is reduced to about 10% at a diurnal temperature amplitude of 20°C.

show abstract

Controls on carbon and energy exchange by a black spruce–moss ecosystem: Testing the mathematical model Ecosys with data from the BOREAS Experiment

Cited by 30 publications

References 62 publications

Modelling carbon balances of coastal arctic tundra under changing climate

Modelling carbon balances of coastal arctic tundra under changing climate

Modeling the diurnal variability of respiratory fluxes in the Canadian Terrestrial Ecosystem Model (CTEM)

Daily heterotrophic respiration model considering the diurnal temperature variability in the soil

Contact Info

Product

Resources

About