NASA-funded project (2005-2008): Testing the flux tower upscaling hypothesis in a complex landscape Paul Bolstad, PI, University of MN, St. Paul Contact information: Nick Saliendra Institute for Applied Ecosystem Studies U.S. Forest Service, Northern Research Station 5985 Hwy K Rhinelander, WI 54501 Telephone: 715-362-1127 Fax: 715-362-1166 E-mail: nsaliendra@fs.fed.us, nickzs1@gmail.com http://www.nrs.fs.fed.us/units/iaes/ Flux Measurements with Roving Eddy Covariance LI-7500 open-path IRGA, CSAT3 3-D sonic anemometer, & CR1000 data logger with CF card Study site: Wilson Flowage (WF), wetland, fen, dominated by grasses, sedges, and shrubs Coordinates, degrees.decimal: 45.81644821 N, 90.17131076 W (NAD83, Zone 15) Filename: WFyyyy_flux-micromet.CSV (comma separated values) WF - Wilson Flowage, yyyy - four digit year of measurements Column Variable Description 1 Year Year of measurements 2 DoY Day of year (Julian day) 3 fDoY DoY + LST/24 4 Mo Month 5 Day Day of the month 6 LST Local standard time 7 C Carbon flux, umol CO2 m-s s-1 8 H Sensible heat flux, W m-2 9 LE Latent heat flux, W m-2 10 fv Friction velocity (or u*), m s-1 11 S Storage flux for carbon, umol CO2 m-2 s-1 S = (((c_tpls1 - c_tmns1)*22.7)/(3600))*3, where c_tpls1 is the mean CO2 density at t+1 (30 minutes after) c_tmns1 is the mean CO2 density at t-1 (30 minutes before) the factor, 22.7, converts mg to umol CO2 3600 s is the time difference from t-1 to t+1 3 m is the height of eddy-covariance sensors 12 NEE Net ecosystem exchange for carbon, umol CO2 m-2 s-1, NEE = C + S 13 modER Modeled ecosystem respiration (ER), umol CO2 m-2 s-1 * Model ecosystem respiration (modER) by Period (Pd) based on the depth of water table; IF 100 <= DoY < 162 THEN Pd = 1; IF 162 <= DoY < 192 THEN Pd = 2; IF 191 <= DoY < 334 THEN Pd = 3; Kair = Tair + 273.15; K0avg = Ts0avg + 273.15; IF DoY < 100 THEN modER = 2.7117*EXP(459.8*((1/(283.15-227.13)-1/(K0avg-227.13)))); IF Pd = 1 THEN modER = 1.2936*EXP(310.6*((1/(283.15-227.13)-1/(Kair-227.13)))); IF Pd = 2 THEN modER = 3.0352*EXP(133.8*((1/(283.15-227.13)-1/(Kair-227.13)))); IF Pd = 3 THEN modER = 1.4582*EXP(351.6*((1/(283.15-227.13)-1/(Kair-227.13)))); IF DoY >= 334 THEN modER = 2.7117*EXP(459.8*((1/(283.15-227.13)-1/(K0avg-227.13)))); 14 modGEP Modeled gross ecosystem production, umol CO2 m-2 s-1 modGEP = (alpha*PARumol*GEPopt)/SQRT(GEPopt**2+(alpha*PARumol)**2) daily parameters, alpha and GEPopt, were gap-filled by smoothing the observed parameters 15 modNEE Modeled NEE = modER - modGEP, umol CO2 m-2 s-1 16 GEP Calculated GEP = modER - NEE, umol CO2 m-2 s-1 17 fillGEP Calculated GEP gap-filled with modeled GEP, umol CO2 m-2 s-1 18 fillER Night-time NEE (or ER) gap-filled with modeled ER, umol CO2 m-2 s-1 19 fillNEE NEE gap-filled with modeled NEE, umol CO2 m-2 s-1 20 P_avg Atmospheric pressure (kPa) from LI-7500 gap-filled with measurements from Willow Creek 21 WDir Wind direction (degrees) from CSAT3 gap-filled with measurements from Willow Creek 22 WSpd Wind speed (m s-1) from CSAT3 gap-filled with measurements from Willow Creek 23 Tair Air temperature (C) measured at a height of 3 m, gap-filled with Tair measurements (at 80 ft) from Willow Creek 24 RH Relative humidity (%) measured at a height of 3 m, gap-filled with RH measurements (at 80 ft) from Willow Creek 25 Precip Total precipitation (mm) measured from nearby clearcut site at Riley Creek, gap-filled with precipitation measurements from Willow Creek 26 PARumol Photosynthetically ctive radiation, umol m-2 s-1, gap-filled with PAR measurements (at 97 ft) from Willow Creek 27 Ts0avg Soil temperature (C) at the ground (water) surface, gap-filled via polynomial regression with surface Tsoil measurements from Willow Creek 28 Ts10avg Soil temperature (C) at 10 cm depth, gap-filled via polynomial regression with 10-cm depth Tsoil measurements from Willow Creek 29 Ts20avg Soil temperature (C) at 20 cm depth, gap-filled via polynomial regression with 20-cm depth Tsoil measurements from Willow Creek 30 Ts30avg Soil temperature (C) at 30 cm depth, gap-filled via polynomial regression with 20-cm depth Tsoil measurements from Willow Creek 31 Ts50avg Soil temperature (C) at 50 cm depth, gap-filled via polynomial regression with 50-cm depth Tsoil measurements from Willow Creek 32 H2O_WF Surface water height (cm above surface) at the study site (not gap-filled) 33 LWREPP Hourly long wave radiation (Eppley, W m-2) from the North Temperate Lakes LTER meteorological station, Woodruff Airport 34 SWREPP Hourly short wave radiation (Eppley, W m-2) from the North Temperate Lakes LTER meteorological station, Woodruff Airport 35 SWRLIC Hourly short wave radiation (Li-Cor, W m-2) from the North Temperate Lakes LTER meteorological station, Woodruff Airport 36 VPD Vapor pressure deficit (kPa) of the air from saturation