BOREAS TE-19 Ecosystem Carbon Balance Model Summary The BOREAS TE-19 team developed a model called the Spruce and Moss Model (SPAM) designed to simulate the daily carbon balance of a black spruce/moss boreal forest ecosystem. It is driven by daily weather conditions, and consists of four components: (1) soil climate; (2) tree photosynthesis and respiration; (3) moss photosynthesis and respiration; and (4) litter decomposition and associated heterotrophic respiration. The model simulates tree gross and net photosynthesis, wood respiration, live root respiration, moss gross and net photosynthesis, and heterotrophic respiration (decomposition of root litter, young needle and moss litter, and humus). These values can be combined to generate predictions of total site net ecosystem exchange of carbon (NEE), total soil dark respiration (live roots + heterotrophs + live moss), spruce and moss net productivity, and net carbon accumulation in the soil. The files include source code and sample input and output files in ASCII format. Table of Contents * 1 Model Overview * 2 Investigator(s) * 3 Model Theory * 4 Equipment * 5 Data Acquisition Methods * 6 Observations* 7 Data Description* 8 Data Organization * 9 Data Manipulations * 10 Errors * 11 Notes * 12 Application of the Model * 13 Future Modifications and Plans * 14 Software * 15 Data Access * 16 Output Products and Availability * 17 References * 18 Glossary of Terms * 19 List of Acronyms * 20 Document Information 1. Model Overview 1.1 Model Identification BOREAS TE-19 Ecosystem Carbon Balance Model 1.2 Model Introduction The Spruce and Moss Model (SPAM) is a model of the daily carbon balance of a black spruce/moss boreal forest ecosystem. It is driven by daily weather conditions, and consists of four components: (1) soil climate, which exerts controls on the dynamics of ecosystem productivity and respiration; (2) tree photosynthesis and respiration; (3) moss photosynthesis and respiration; and (4) litter decomposition and associated heterotrophic respiration. The soil climate component of the model is based on the peatland soil climate model of Frolking and Crill (1994). The tree canopy component of the model carbon balance is a daily time-step version of the PnET model (Aber and Federer 1992; Aber et al. 1996). A similar photosynthesis and respiration model was developed for the moss, based on published physiological behavior of feathermosses. The decomposition component determines heterotrophic respiration as a function of litter age and soil temperature and moisture. The model operates on a daily time-step and considers only short-term simulations. It ignores features of the forest carbon balance that are important in longer scenarios (e.g., wood growth and storage, limb turnover, tree mortality, changing nutrient constraints on productivity, fire). The model simulates tree gross and net photosynthesis, wood respiration, live root respiration, moss gross and net photosynthesis, heterotrophic respiration (decomposition of root litter, young needle and moss litter, and humus). These values can be combined to generate predictions of total site net ecosystem exchange of carbon (NEE), total soil dark respiration (live roots + heterotrophs + live moss), spruce and moss net productivity, and net carbon accumulation in the soil. 1.3 Objective/Purpose Under the premise that mean annual air temperature and/or precipitation are the dominant controls of net ecosystem productivity (net carbon exchange between a terrestrial ecosystem and the atmosphere), Dai and Fung (1993) applied a simple model of terrestrial ecosystem production and respiration, driven by these variables, at a global scale. This model predicted deviations (from an assumed global equilibrium for 1920-1949) in net carbon flux between the atmosphere and terrestrial ecosystems. Their results suggested that interannual variabilities in mean annual air temperature and total annual precipitation have had a significant impact on the global carbon balance, and may account for some of the so-called "missing sink" for atmospheric CO2. Their model also suggested that the northern boreal zone was the dominant region for carbon sequestration over the past several decades. Steve Frolking has developed a model of the daily carbon balance of a spruce/moss boreal forest stand that can be used to address the general question: 1. What is the sensitivity of the boreal forest carbon balance to weather variability? More specifically: 2. What are the differences in the sensitivities of carbon gains (photosynthesis) and carbon losses (respirations)? 3. Are there different seasonalities to these sensitivities? For example, will a warmer spring have one effect and a warmer summer a different effect? 4. What is the effect of an earlier (later) snowmelt and spring thaw? 5. How different are the carbon balance sensitivities of the overstory tree species and the often ubiquitous moss or lichen ground cover? 6. Due to weather variability, how noisy will any carbon flux or carbon pool signal be that we might use to try to detect change? 1.4 Summary of Parameters The model requires basic site description (masses of organic horizon, sapwood, foliage, roots) and daily weather data (maximum/minimum air temperatures, precipitation, also Photosynthetically Active Radiation (PAR) and relative humidity if available). The model outputs are daily values for soil temperature profiles, soil moisture profiles, and carbon exchanges of various ecosystem components (tree, moss, and soil). 1.5 Discussion This model is a daily time-step model with submodels of soil climate, tree net primary production (NPP), moss NPP, and decomposition. Our goal was to develop parameters from non-BOReal Ecosystem-Atmosphere Study (BOREAS) literature (at least initially) and see how well these, along with BOREAS site description data, could emulate observed fluxes. A related non-BOREAS model is PnET Model (Aber and Federer, 1992; Aber et al. 1996). 1.6 Related Models and Datasets BOREAS RSS-08 BIOME-BGC Model Simulations at Tower Flux Sites in 1994 BOREAS RSS-08 BIOME-BGC SSA Simulations of Annual Water and Carbon Fluxes BOREAS TE-01 SSA Soil Lab Data BOREAS TE-01 Soils Data over the SSA Tower Sites in Raster Format BOREAS TE-05 Soil Respiration Data BOREAS TE-06 NPP for the Tower Flux, Carbon Evaluation, and Auxiliary sites BOREAS TE-17 Global Primary Efficiency Model BOREAS TE-20 Stem Map Data BOREAS TE-20 NSA Soil Lab Data BOREAS TGB-12 Soil Carbon Data over the NSA 2. Investigator(s) 2.1 Investigator(s) Name and Title Steve Frolking John Aber Changsheng Li 2.2 Title of Investigation Modeling Climate-Biosphere Interactions in the Boreal Forest 2.3 Contact Information Contact 1: Steve Frolking Institute for the Study of Earth, Oceans, and Space University of New Hampshire Durham, NH (603) 862-0244 (603) 862-0188 (fax) steve.frolking@unh.edu Contact 2: Andrea Papagno Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-3134 (301) 286-0239 (fax) Andrea.Papagno@gsfc.nasa.gov 3. Model Theory Each component of the model takes a fairly standard and simple approach. Soil temperatures and heat flow are determined by 1-D heat diffusion; freeze/thaw by apparent heat capacity method (see, for example, Lunardini, 1981). Soil moisture is determined using the modified bucket for surface organic layer, with a simplified Richards Equation for mineral soil (gravity flow only, or unit hydraulic gradient) (see, for example, Hillel, 1980). Tree NPP is determined from layered canopy (light level changes); photosynthesis is a function of temperature, water, and light, with base rate determined by leaf nitrogen (or specified). Foliar respiration is a function of leaf mass and temperature. Sapwood and root respiration are functions of temperature and volume (sapwood) or nitrogen (roots), (see Aber and Federer, 1992). Moss NPP is similarly determined with a layered canopy (light level and temperature change). Respiration is a function of moss temperature and moss water content (see Frolking et al., 1996). The decomposition model tracks annual litter cohorts. These each have a base decomposition rate, which declines as the litter ages. The realized rate of decomposition is this base rate modified by temperature and moisture. After a specified number of years (about 20-40), the litter is transferred to a single humus pool, with a fixed decomposition rate, which is also modified by soil temperature and moisture (see Frolking et al., 1996). 4. Equipment The model is currently run on an SGI Indigo system. The software is written in standard FORTRAN and should be very portable. The model does not require a lot of space, and 1-year simulations take only a few minutes. 5. Data Acquisition Methods The model requires two input files: (1) site description, file names, etc. and (2) daily weather data. Once these are in place, just run the model. When it is done, there will be nine output files (input information, soil temperature, soil moisture, soil ice, one each for the daily carbon balance of moss, trees, decomposition, site, and an accumulating carbon balance). These are just text files, with one line for each day (See Sections 7.3 and 7.4 for details). 6. Observations 6.1 Data Notes The model requires a daily weather file: maximum and minimum air temperatures, total precipitation, daily average relative humidity, and daytime average PAR (µmol photon/meters2/second). These last two can be calculated internally if they are unavailable (relative humidity by assuming saturation at minimum daily temperature, and PAR by a fit from 1994 BOREAS Northern Study Area (NSA)-Old Black Spruce (OBS) data to diurnal temperature range). 6.2 Field Notes Not applicable. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The model is 1-D, so a single run covers a single 'uniform' plot, e.g., very roughly 1 ha. 7.1.2 Spatial Coverage Map To date, simulations have been of BOREAS tower sites: NSA-OBS and Southern Study Area (SSA)-OBS. 7.1.3 Spatial Resolution Not applicable. 7.1.4 Projection Not applicable. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage Simulations are generally one to several years (up to about 20 years so far). 7.2.2 Temporal Coverage Map To date, simulations have been from 1968-95 (except 1990-93). 7.2.3 Temporal Resolution Daily time-step. 7.3 Input Data Characteristics Input information for the model is contained in two tabular ASCII files. File number one contains needed duration and ‘weather’ data. File number two contains site information and input and output file names. Samples of these files are provided. The weather data file contains n+1 records where n is the number of days of the simulation. The values on each record are separated by commas. INPUT FILE #1 (WEATHER DATA): File contents: Record Number Variable Name Description Measurement Units 1 year nday Days of simulation mean annual air temp depth of constant temp in soil latitude permafrost flag Year in which simulation begins The day of year on which the simulation begins The number of days to be simulated. The mean annual air temperature The soil depth at which the temperature remains constant during the year. The latitude of the location being simulated. The flag indicating whether or not permafrost is present year date count degrees Celsius centimeters degrees 1=yes, 0=no 2 to n+1 doy Tmin Tmax daily ppt relative humidity PPFD (daytime average) The day of year. The minimum air temperature for the given day of year. The maximum air temperature for the given day of year. The daily precipitation for the given day of year. The average relative humidity for the given day of year. The average photosynthetic photon flux density for the given day of year. date degrees Celsius degrees Celsius millimeters percent micromole/meters2/second INPUT FILE #2 (SITE DATA): File Contents: Record Number Variable Name Description Measurement Units 1 ground veg type tree type shrub type The coded value that designates the dominant type of ground vegetation at the site. (1=feathermoss;2=sphagnum ;3=lichen) The coded value that designates the dominant type of trees at the site.(0=none;1=maple,2=oa k, 3=pine;4=spruce) The coded value that designates the dominant type of shrub at the site.(0=none;1=deciduous) Coded but unitless value Coded but unitless value Coded but unitless value 2 canopy closure stem area index LAI (not used) total live fine root mass sapwood volume The fraction of canopy closure expressed from 0.0 to 1.0. The stem area index. The Leaf Area Index. The total Carbon mass density in live fine roots at the site. The sapwood volume density at the site. unitless unitless unitless grams Carbon/meter2 meters3/meter2 3 average annual foliar litterfall fine root turnover rate total mass of organic layer total mass of old carbon layer The average annual foliar litterfall density at the site. The rate of fine root density turnover. The total mass density of the organic layer. The total mass density of the old carbon layer, which is the bottom-most part of the surface organic layer. grams/meter2 grams/meter2/year grams/meter2 grams/meter2 4 Mineral soil layer #1 SOC content Mineral soil layer #2 SOC content Mineral soil layer #3 SOC content Mineral soil layer #4 SOC content The soil organic carbon content of the 0-10 cm deep mineral soil layer. The soil organic carbon content of the 10-30 cm deep mineral soil layer. The soil organic carbon content of the 30-70 cm deep mineral soil layer. The soil organic carbon content of the 70-150 cm deep mineral soil layer. grams Carbon/meter2 grams Carbon/meter2 grams Carbon/meter2 grams Carbon/meter2 5 first year litter mass loss rate The first year litter mass loss rate based on AET, Berg et al 1993. (generally 0.05-0.15 for BOREAS sites) year-1 6 climate modifier for decomposition decomp parameter (generally 1) The climate modifier for decomposition. (generally around 200) The decomposition parameter. (ignore for soil climate runs) unitless unitless 7 mineral soil type The coded value that designates the mineral soil type. (1=sand; 2=loam; 3=clay; 4=peat) Coded but unitless value 8 thickness of mineral soil layers The thickness of mineral soil layers used in the model [leave alone for now]. centimeters 9 number of layers plus 1 The number of soil layers plus 1. (4 organic + 4 mineral + 1) (keep at 9) count 10 initial soil temp profile The initial temperature of each soil layer at the start of the model run. degrees Celsius 11 file name for input weather file The name of the input file containing weather information. None 12 Output Temperature file The name of the output file to contain the temperature data. None 13 Output Soil Moisture file The name of the output file to contain the soil moisture data. None 14 Output Soil Ice file The name of the output file to contain the soil ice data. None 15 Output Other things file The name of the output file to contain the other things data. None 16 Output Litter Respiration file The name of the output file to contain the litter respiration data. None 17 Output moss file The name of the output file to contain the moss data. None 18 Output tree file The name of the output file to contain the tree data. None 19 Output Daily Carbon file The name of the output file to contain the daily carbon total data. None 20 Output Carbon Accumulations file The name of the output file to contain the daily accumulating carbon data. None 7.3.4 Input Data Source The weather and site data used was gathered during the BOREAS field campaigns in 1994 and 1996. See Sections 15 and 16 for data availability. 7.3.5 Data Range None given. 7.4 Output Data Characteristics Output information from the model is contained in nine tabular ASCII files. File number: 1 - General Information 2 - Soil Temperature 3 - Soil Moisture 4 - Soil Ice 5 - Tree Carbon Balance 6 - Moss Carbon Balance 7 - Decomposition Carbon Balance 8 - Site Carbon Balance 9 - Site Carbon Accumulations The output file records contain combinations of text and output values. Those records with lists of column headings or numbers have the strings and values separated by blank spaces. OUTPUT FILE #1 (GENERAL INFORMATION) File contents: Record Number Variable Name Description Measurement Units 1 Repeats much of the input data, lists the input and output filenames, and describes the soil profile. See variable name. See variable name. OUTPUT FILE #2 (SOIL TEMPERATURE) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog ice T1 T2 T3 T4 T5 T6 T7 T8 T9 The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snow depth. The thickness of the soil ice. The soil temperature at the top of the moss layer. The soil temperature at the bottom of the moss layer. The soil temperature at the bottom of the litter layer. The soil temperature at the bottom of the humus layer. The soil temperature at the top of the mineral layer. The soil temperature at the bottom of the first mineral layer. The soil temperature at the bottom of the second mineral layer. The soil temperature at the bottom of the third mineral layer. The soil temperature at the bottom of the fourth mineral layer. date date degrees Celsius centimeters centimeters centimeters degrees Celsius degrees Celsius degrees Celsius degrees Celsius degrees Celsius degrees Celsius degrees Celsius degrees Celsius degrees Celsius OUTPUT FILE #3 (SOIL MOISTURE) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog gvw llw hlwl hlw2 oclw slw1 slw2 slw3 slw4 gloss lloss hloss aet ttrns strns pet vpd drain The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snowdepth. The water content of the moss. The water content of the litter layer. The water content number 1 of the humus layer. The water content number 2 of the humus layer. The water content of the ‘old carbon layer’. The water content number 1 of the mineral soil layer. The water content number 2 of the mineral soil layer. The water content number 3 of the mineral soil layer. The water content number 4 of the mineral soil layer. The rate of water loss from the moss layer. The rate of water loss from the litter layer. The rate of water loss from the humus layer. The total actual evapotranspiration. The tree transpiration. The shrub transpiration. The potential evapotranspiration. The vapor pressure deficit. The rate of water drainage. date date degrees Celsius centimeters centimeters fraction of saturation fraction of saturation fraction of saturation fraction of saturation fraction of saturation fraction of saturation fraction of saturation fraction of saturation fraction of saturation millimeters/day millimeters/day millimeters/day centimeters/day centimeters/day centimeters/day centimeters/day kiloPascals millimeters/day OUTPUT FILE #4 (SOIL ICE) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog ice top1 bot1 top2 bot2 ice1 ice2 ice3 ice4 ice5 ice6 ice7 ice8 The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snowdepth. The thickness of the soil ice. The depth to the top of the first ice layer. The depth to the bottom of the first ice layer. The depth to the top of the second ice layer. The depth to the bottom of the second ice layer. The ice content of layer 1 (moss) in the model. The ice content of layer 2 (litter) in the model. The ice content of layer 3 (humus) in the model. The ice content of layer 4 (old carbon layer) in the model. The ice content of layer 5 (0-10 cm mineral) in the model. The ice content of layer 6 (10-30 cm mineral) in the model. The ice content of layer 7 (30-70 cm mineral) in the model. The ice content of layer 8 (70-150 cm mineral) in the model. date date degrees Celsius centimeters centimeters centimeters centimeters centimeters centimeters centimeters fraction of frozen content fraction of frozen content fraction of frozen content fraction of frozen content fraction of frozen content fraction of frozen content fraction of frozen content fraction of frozen content OUTPUT FILE #5 (TREE CARBON BALANCE) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog trlai shlai tgrpsn tnetpsn sgrpsn snetpsn tlitfal slitfal dvpd dwater dtemp The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snowdepth. The leaf area index (projected). The foliar mass. The gross photosynthesis of the trees. The net foliar photosynthesis of the trees. The gross photosynthesis of the shrubs. The net foliar photosynthesis of the shrubs. The litterfall from the trees. The litterfall from the shrubs. The vapor pressure deficit multiplier for photosynthesis (0-1). The soil water multiplier for photosynthesis (0-1). The temperature multiplier for photosynthesis (0-1). date date degrees Celsius centimeters centimeters unitless kilogram/meter2 grams Carbon /meters2/day grams Carbon /meters2/day grams Carbon /meters2/day grams Carbon /meters2/day kilogram/meter2 kilogram/meter2 unitless unitless unitless OUTPUT FILE #6 (MOSS CARBON BALANCE) Record Number Variable Name Description Measurement Units 1 column headings Column headings. None. 2 to n nday doy tair ppt sog par iomoss grpsn grres netpsn F1(T) F2(W) F3(L) fr(W) fr(T) The day of the simulation The day of year The mean air temperature The daily precipitation The snowdepth The daily average photosynthetically active radiation at the top of the tree canopy The daily average photosynthetically active radiation at the top of the moss canopy The gross photosynthesis The gross respiration The net photosynthesis The moss temperature multiplier for photosynthesis (0-1) The moss water multiplier for photosynthesis (0-1) The photosynthetically active radiation multiplier for photosynthesis (0-1) The moss water multiplier for respiration (0-1) The moss temperature multiplier for respiration (0-8). date date degrees Celsius centimeters centimeters micromole/m2/second micromole/m2/second grams Carbon/meters2/day grams Carbon/meters2/day grams Carbon/meters2/day unitless unitless unitless unitless unitless OUTPUT FILE #7 (DECOMPOSITION CARBON BALANCE) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog llres hlres oclres droot1 droot2 droot3 droot4 droot5 droot6 droot7 liveroot sapwood lrdtemp The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snowdepth. The decomposition respiration of the litter layer. The decomposition respiration of the humus layer. The decomposition respiration of the old carbon layer. The decomposition respiration of the dead roots in the moss layer (always 0). The decomposition respiration of the dead roots in the litter layer. The decomposition respiration of the dead roots in the humus layer. The decomposition respiration of the dead roots in the mineral soil layer #1. The decomposition respiration of the dead roots in the mineral soil layer #2. The decomposition respiration of the dead roots in the mineral soil layer #3. The decomposition respiration of the dead roots in the mineral soil layer #4. The respiration of the live roots The sapwood respiration. The soil temperature multiplier for respiration (0-8). date date degrees Celsius centimeters centimeters grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams Carbon/meter2/day grams carbon/meter2/day grams Carbon/meter2/day unitless OUTPUT FILE #8 (SITE CARBON BALANCE) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog psndorm tnetpsn snetpsn mnetpsn rootrsp hetresp woodresp totresp netcx The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snowdepth. The photosynthesis dormancy multiplier. The foliar net primary production of the trees. The foliar net primary production of the shrubs. The net primary production of the moss. The respiration of the live roots. The total heterotrophic respiration. The sapwood respiration. The total respiration. The net ecosystem exchange. date date degrees Celsius centimeters centimeters unitless grams Carbon /meter2/day grams Carbon /meter2/day grams Carbon /meter2/day grams Carbon /meter2/day grams Carbon /meter2/day grams Carbon /meter2/day grams Carbon /meter2/day grams Carbon /meter2/day OUTPUT FILE #9 (SITE CARBON ACCUMULATIONS for 1 January through 31 December) Record Number Variable Name Description Measurement Units 1 column headings The column headings. None 2 to n nday doy tair ppt sog mgrresp mgrpsn shgrrsp shgrpsn tgrresp trgrpsn hetresp rootrsp woodrsp netcx The day of the simulation. The day of year. The mean air temperature. The daily precipitation. The snowdepth. The accumulation of the gross respiration of the moss. The accumulation of the gross photosynthesis of the moss. The accumulation of the foliar gross respiration of the shrubs. The accumulation of the foliar gross photosynthesis of the shrubs. The accumulation of the foliar gross respiration of the trees. The accumulation of foliar gross photosynthesis of the trees. The accumulation of the heterotrophic respiration of the soil. The accumulation of the respiration of the live roots. The accumulation of the respiration of the live sapwood. The accumulation of the net ecosystem exchange. date date degrees Celsius centimeters centimeters grams Carbon /meter2 grams Carbon /meter2 grams Carbon /meter2 grams Carbon /meter2 grams Carbon/meter2 grams Carbon/meter2 grams Carbon/meter2 grams Carbon/meter2 grams Carbon/meter2 grams Carbon/meter2 7.4.4 Data Source The files are output files from the model. 7.4.5 Data Range None given. 7.5 Sample Data Records The following are sample records from the 2 input and the 9 output data files. INPUT FILE #1 (WEATHER DATA): 288, 1537, 0.5, 200.0 , 56., 0 288 3.2 5.8 0.25 52.7 93.1 INPUT FILE #2 (SITE DATA): 1,4 0.75, 1.0, 2.0, 400.0, 0.0083 80., 0.25, 24000. 0.15 198., 1.0 3 10.0, 20.0, 40.0, 80.0 8 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 thom.67-89.cli gwr.temp.67-89.14 gwr.wat.67-89.14 gwr.ice.67-89.14 gwr.other.67-89.14 gwr.carb.67-89.14 gwr.moss.67-89.14 gwr.tree.67-89.14 gwr.sum.67-89.14 gwr.accum.67-89.14 OUTPUT FILE #1 (GENERAL INFORMATION) Run of model bcm6t.f soil type (1=sandy,2=loamy,3=clayey,4=wetland): 3 permafrost present (0=no,1=yes): 0 ground veg.(1=feathermoss,2=sphagnum,3=lichen): 1 trees (0=none,1=maple,2=oak,3=pine,4=spruce): 4 fraction of canopy closure: 0.75 sapwood volume [m3/m2]: 0.0083 stem area index: 1.00 leaf area index: 2.00 average annual tree foliar litterfall [g/m2/y]: 80.0 soil organic horizon (live+L+F+H) mass [g/m2]: 24000.0 annual mass loss rate for first year litter: 0.150 annual turnover rate for fine root biomass: 0.250 total live fine root biomass carbon [g C/m2]: 400.0 total dead fine root biomass carbon [g C/m2]: 666.7 weather data input file name: nelhse.94-95.cli soil temperature output file name: gwr.temp.94-5.14 soil moisture output file name: gwr.wat.94-5.14 soil ice output file name: gwr.ice.94-5.14 litter respiration output file name: gwr.carb.94-5.14 moss output file name: gwr.moss.94-5.14 tree output file name: gwr.tree.94-5.14 daily carbon output file name: gwr.sum.94-5.14 annual accums output file name: gwr.accum.94-5.14 model layer thicknesses [cm]: 3.0 2.3 10.6 10.6 10.0 20.0 40.0 80.0 litter layer has 14 cohorts: #2 cohort mass (g/m2) is 113.04 #11 cohort mass (g/m2) is 52.00 #21 cohort mass (g/m2) is 0.00 bottom cohort mass (g/m2) is 44.07 organic layer masses [g/m2]: live veg.: 990.0 litter: 876.7 humus: 20426.7 organic horizon water contents [cm water depth]: minimum no drainage field cap. saturation porosity ground veg 0.040 0.168 0.520 2.924 0.975 litter layer 0.043 0.173 0.519 2.174 0.942 humus layer 0.532 4.256 6.384 19.643 0.923 OUTPUT FILE #2 (SOIL TEMPERATURE) [all temps in degC] nday doy tair ppt sog ice T1 T2 T3 T4 T5 T6 T7 T8 808 365 -22.0 0.0 21.3 16.1 -2.04 -1.48 -1.30 -0.72 -0.02 0.04 0.13 0.30 OUTPUT FILE #3 (SOIL MOISTURE) [all water content as fraction of saturation] nday doy tair ppt sog gvw llw hlw1 hlw2 slw1 slw2 slw3 slw4 gloss lloss hloss aet trans vpd drain runoff 808 365 -22.05 0.00 21.34 0.102 0.239 0.224 0.158 0.513 0.537 0.533 0.570 0.000 0.000 0.000 0.018 0.000 0.020 0.01 0.00 OUTPUT FILE #4 (SOIL ICE) [soil layer ice content given as fraction frozen, 0-1] nday doy tair ppt sog ice top1 bot1 top2 bot2 ice1 ice2 ice3 ice4 ice5 ice6 ice7 808 365 -22.0 0.0 21.3 16.1 0.0 -16.1 0.0 0.0 1.00 1.00 0.93 0.37 0.00 0.00 0.00 OUTPUT FILE #5 (TREE CARBON BALANCE) [all C fluxes in g C/m2/d; pools in g C/m2] nday doy tair ppt sog lai folmas grspsn netpsn litfall dvpd dwater dtemp canopytrans 808 365 -22.0 0.0 21.3 2.88 720.0 0.00 0.10 0.00 1.00 0.22 0.00 0.00 OUTPUT FILE #6 (MOSS CARBON BALANCE) [all C fluxes in g C/m2/d; pools in g C/m2] nday doy tair ppt sog par iomoss grpsn grres _netpsn f1(T) F2(W) F3(L) fr(W) fr(T) 808 365 -22.0 0.0 21.3 155.400 4.357 0.000 0.000 0.000 0.000 0.890 0.025 0.000 0.000 OUTPUT FILE #7 (DECOMPOSITION CARBON BALANCE) [all C fluxes in g C/m2/d; pools in g C/m2] nday doy tair ppt sog llres hlres droot1 droot2 droot3 droot4 droot5 droot6 liveroot sapwood lrdtemp nan 38.8697 206.5596 199.0533 808 365 -22.0 0.0 21.3 0.081 0.129 0.000 0.008 0.018 0.012 0.040 0.000 0.000 0.000 0.927 OUTPUT FILE #8 (SITE CARBON BALANCE) [all C fluxes in g C/m2/d; pools in g C/m2] nday doy tair ppt sog tnetpsn mnetpsn rootrsp hetresp soildr totresp netcx 808 365 -22.0 0.0 21.3 0.099 0.000 0.000 0.288 0.288 0.387 0.387 OUTPUT FILE #9 (SITE CARBON ACCUMULATIONS) [all C fluxes in g C/m2; pools in g C/m2] nday doy tair ppt sog tnetpsn tgrpsn mnetpsn mgrresp rootrsp woodrsp hetresp soilresp soildresp netcx 808 365 -22.0 0.0 21.3 0.10 0.00 0.00 0.00 0.00 0.00 0.29 0.29 0.29 0.39 8. Data Organization 8.1 Data Granularity The source code file for the model along with the 2 input files and 9 output files comprise this data set. 8.2 Data Format(s) Source code and sample input and output files are American Standard Code for Information Interchange (ASCII) files. 9. Data Manipulations 9.1 Formulae Tree NPP = foliar NPP + wood respiration + root respiration 9.1.1 Derivation Techniques and Algorithms None given. 9.2 Data Processing Sequence 9.2.1 Processing Steps The model is run, and the results are then studied. 9.2.2 Processing Changes The model was revised periodically as mistakes were discovered or new applications were attempted. Contact the Principal Investigator (PI) for the latest version. 9.3 Calculations 9.3.1 Special Corrections/Adjustments None given. 9.3.2 Calculated Variables None given. 9.4 Graphs and Plots None given. 10. Errors 10.1 Sources of Error Sources of error are abundant, including an incomplete understanding of the ecosystem, an imprecise description of the site, and the averaging of nonlinear processes. 10.2 Quality Assessment 10.2.1 Model Validation by Source Model results have been compared to tower flux, chamber flux, soil temperature, and soil moisture measurements for the BOREAS NSA-OBS site (Frolking et al., 1996). Unpublished comparisons were made with SSA-OBS tower flux. 10.2.2 Confidence Level/Accuracy Judgment As BOREAS data become available, input data should generally be adequate (i.e. not the weak link). Output quality is harder to evaluate. Terrestrial Ecology (TE)-19 feels that the absolute numbers are 'spot-on' (i.e., generally within 50% of reality). TE-19 has more confidence in the overall sensitivity of the model results to weather variability. Model output, particularly overall site carbon balance, is very sensitive to some model parameters that are poorly constrained by current data sets (see discussion in Frolking et al., 1996). 10.2.3 Measurement Error for Parameters Latest r2 of model against the preliminary tower data (daily NEE) for NSA-OBS 1994-95 is about 0.6 (n~300). 10.2.4 Additional Quality Assessments See Frolking et al., 1996. 10.2.5 Data Verification by Data Center Model information was examined for general consistency and clarity. 11. Notes 11.1 Limitations of the Model The model contains vegetation parameters for two boreal tree types: pine and spruce, and three boreal groundcovers: feathermoss, sphagnum moss, and lichen (e.g. cladina). Virtually all of the model evaluation has been done for spruce and feathermoss. The other parameterizations have been run and although they produced seemingly unbelievable results, they have not been evaluated adequately. 11.2 Known Problems with the Model Several components of the model are poorly tested or untested, and several are clearly wrong. Among these are: A. The algorithm for the location of ice layers in soil does not work, particularly for soils with permafrost. The model considers soil water to freeze from 0 to 100% as soil temperature drops from 0 to -1 °C; this leaves an ambiguous 'slush' zone. The total ice thickness within the profile is probably a more reasonable number. B. Site water balance is not well tested; simulated surface run-off and drainage from the bottom of the profile are not reliable. C. Spruce foliar and root litterfall are the same each year, and occur on a single day. There is undoubtedly interannual variability in the field. Timing of litterfall may or may not have a strong influence on site carbon balance. D. There are indications from the tower data that the vegetation’s photosynthetic machinery takes a while to get up to full speed after thawing; the model does not include a phenological factor and thus overestimates early growing season productivity. 11.3 Usage Guidance The model results may not be reliable as absolute numbers; interannual and intra-annual trends and relative numbers are the main objective of the study. The comparison of sensitivities of moss, trees, and decomposition to weather variability was an additional objective. 11.4 Other Relevant Information None given. 12. Application of the Model Anyone is welcome to obtain a copy of the model and use it for their own research. Contact the PI. 13. Future Modifications and Plans The development of versions/parameterizations for pine/lichen, pine/moss, and aspen/hazel is in progress. The development of a peatland version is planned. 14. Software 14.1 Software Description The model source code is in FORTRAN and runs on a Unix workstation; the code does not use any machine-specific commands. It reads ASCII files as input and generates ASCII files as output. 14.2 Software Access The source code is available to anyone. Please send an e-mail to the PI (see Section 2.3). 14.3 Platform Limitations There should not be any platform limitations. 15. Data Access 15.1 Contact for Data Center/Data Access Information These BOREAS data are available from the Earth Observing System Data and Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 15.2 Procedures for Obtaining Data BOREAS data may be obtained through the ORNL DAAC World Wide Web site at http://www-eosdis.ornl.gov/ or users may place requests for data by telephone, electronic mail, or fax. 15.3 Output Products and Availability Requested data can be provided electronically on the ORNL DAAC's anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes, or diskettes. The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are also available. 16. Output Products and Availability 16.1 Tape Products None. 16.2 Film Products None. 16.3 Other Products Source code and sample input and output files are available on the BOREAS CD-ROM series.17. References 17.1 Model Documentation Some documentation is in the model code as comments, and some is in the publications listed in Section 17.2). 17.2 Journal Articles and Study Reports Aber J.D. and Federer C.A. 1992. A Generalized, Lumped Parameter Model Of Photosynthesis, Evaporation And Net Primary Production In Temperate And Boreal Forest Ecosystems. Oecologia, 92, 463-474. Aber J.D., P.B. Reich, and M.L. Goulden. 1996. Extrapolating Leaf CO2 Exchange To The Canopy: A Generalized Model Of Forest Photosynthesis Compared With Measurements By Eddy Correlation, Oecologia, 106:257-265. Dai and Fung. 1993. Can Climate Variability Contribute To The “Missing” CO2 Sink? Global Biogeochemical Cycles. 7:599-610. Frolking, S., M.L. Goulden, S.C. Wofsy, S.M. Fan, D.J. Sutton, J.W. Munger, A.M. Bazzaz, B.C. Daube, P.M. Crill, J.D. Aber, L.E. Band, X. Wang, K. Savage, T. Moore, and R.C. Harriss. 1996. Temporal Variability In The Carbon Balance Of A Spruce/Moss Boreal Forest, Global Change Biology, 2:343-366. Frolking, S. 1996. Sensitivity Of Spruce/Moss Boreal Forest Carbon Balance To Seasonal Anomalies In Weather, in press at J. Geophysical Research, 29,053- 29,064. Frolking, S. and P.M. Crill. 1994. The Peatland Soil Climate Model. Hillel D. 1980. Fundamentals of Soil Physics. Academic Press. San Diego. 413 pp. Lunardini, V. 1981. Heat Tranfer in Cold Climates. Van Nostrand Reinhold, New York. 731 pp. Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPSDOC 96). Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPSDOC 94). Sellers, P.J., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The Boreal Ecosystem-Atmosphere Study (BOREAS): An overview and early results from the 1994 field year. Bull. Am. Meteorol. Soc. 76:1549-1577. Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS in 1997: Experiment overview, scientific results, and future directions. Journal of Geophysical Research, 102 (D24), 28,731-28,769. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms ASCII - American Standard Code for Information Interchange BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System CD-ROM - Compact Disk-Read-Only Memory CFS - Canadian Forest Service DAAC - Distributed Active Archive Center DOY - Julian Day of Year EOS - Earth Observing System EOSDIS - EOS Data and Information System GSFC - Goddard Space Flight Center HTML - HyperText Markup Language IFC - Intensive Field Campaign MIX - Mixed Wood NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NEE - Net Ecosystem Exchange of Carbon NOAA - National Oceanic and Atmospheric Administration NPP - Net Primary Production NSA - Northern Study Area OA - Old Aspen OBS - Old Black Spruce ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park PAR - Photosynthetically Active Radiation PI - Principal Investigator SPAM - Spruce and Moss Model SSA - Southern Study Area TE - Terrestrial Ecology TF - Tower Flux URL - Uniform Resource Locator UTM - Universal Transverse Mercator 20. Document Information 20.1 Document Revision Date Submitted: 07-Nov-1996 Last Updated 06-May-1999 20.2 Document Review Date(s) BORIS Review: 08-Apr-1999 Science Review: 20.3 Document ID 20.4 Citation When using data generated from this model, please acknowledge S. Frolking, PI, and cite relevant publications as listed in Section 17.2. 20.5 Document Curator 20.6 Document URL KEYWORDS: Black spruce Carbon Feathermoss Interannual variability Model Moss NEE NEP TE19_Model.doc 06/09/99