Eddy covariance site in Lavrentiya, Russia Responsible investigator: D. Zamolodchikov, Russian Academy of Sciences dzamolod@cepl.rssi.ru, dzamolod@hotbox.ru Introduction The tower based measurements of water, energy and CO2 fluxes and chamber based measurements of net carbon flux, ecosystem respiration and production were continued in Lavrentiya field site, Chukotskiy peninsula, Russia. This site was initiated in 2000, when continuous eddy covariance measurements were performed between July 22 and October 16. The measurements were renewed in 18 of June, 2001 and are continued at present time. The study object is typical tundra with dwarf-shrub (Betula, Salix, Empetrum, Vaccinum) hummocks and (Carex-Eriophorum) lowlands. Site Details Hummock dwarf shrub mosses-lichens tundra Location: N 65o 35.69' W 171o 03.15' (Magellan GPS-200) Elevation: 94 m Slope: 1-2o Exposure: East Data dates: 7/22/00-10/16/00, 6/19/01-date Measurements Fluctuations in vertical and horizontal wind speed and temperature are measured at 10 Hz using a three-dimensional sonic anemometer-thermometer (Gill R3, Gill Inc.). CO2 and H2O vapor fluctuations are measured using open-path infra-red gas analyzer (IRGA) designed by NOAA/ATDD. The sensors were mounted approximately 3 m above ground level. Meteorological conditions are registered and stored using a datalogger (Model CR 21X, Campbell Scientific Inc., Ogden, UT). Measured values included net radiation, soil heat fluxes, air temperature and relative humidity, and soil temperatures at different depths. Soil moisture, thaw depth and water table are measured every 7 days of warm season on 8 transects in directions from eddy system to North, North-West, West etc. Each transect is 100 m long and had a permanent sample points every 10 m marked by flags. Thaw depths were measured by inserting a steel rod to the point of refusal in 3 random repetitions near every flag. Water table was measured in permanent water wells (2 per every transect) 5 cm in diameter made down to the permafrost. Volumetric soil moisture having been estimated by measuring of dielectric resistance of soil at the thaw depth sample points using a "Vitel Hydralogger" portable probe. This instrument was calibrated gravimetrically in 2000 field season by 185 volumetric soil with contrasting moisture. Data Description Data is saved in four tab delimited text files where û9999 indicates missing or bad data. The files are: LAV_FTP_2000.txt LAV_FLX_2000.txt LAV_FTP_2001.txt LAV_FLX_2001.txt Flux Data (FLX) Columns Parameter Units Description YY Year JD Julian day TM "Zone 11, RU" "Local time, Zone 11 of Russian Federation, GMT+12 or GMT+13(DST)" Rn (W m-2) Net radiation LE (W m-2) Latent heat flux H (W m-2) Sensible heat flux G1 (W m-2) "Ground heat flux, moist lowland" G2 (W m-2) "Ground heat flux, drained upland" PAR (microE m-2 s-1) PAR Air T (C) Air temperature Soil T1_0 (C) "Soil surface temperature, moist lowland" Soil T1_5 (C) "Soil temperature at 5 cm, moist lowland" Soil T1_10 (C) "Soil temperature at 10 cm, moist lowland" Soil T2_0 (C) "Soil surface temperature, drained upland" Soil T2_5 (C) "Soil temperature at 5 cm, drained upland" Soil T2_10 (C) "Soil temperature at 10 cm, drained upland" RH (%) Relative humidity of air WD (deg) Wind direction WS (m s-1) Horizontal wind speed u* (m s-1) Friction velocity FCO2 (gC m-2 hr-1) CO2 flux FH2O (mg m-2 s-1) H2O flux Footprint Data (FTP) Columns Parameter Unit Description Notes YY Year JD Julian day Transect Direction of transect from tower position "0 = North, 90 = East, 180 = South, etc." Point Number of point on transect "1 = 10 m from tower, 3 = 30 m from tower, 7 = 70 m from tower, etc." TD1 cm First measurement of thaw depth at point The value means depth from soil surface to frozen ground level TD2 cm Second measurement of thaw depth at point The value means depth from soil surface to frozen ground level TD3 cm Third measurement of thaw depth at point The value means depth from soil surface to frozen ground level WT cm Water table at point "Depth from soil surface to water table surface, 0 = water table at soil surface. Only points 4 and 8 in each transect had water table holes" SM1 % First measurement of volumetric soil moisture at point The value is estimated based on Vitel readings by specific equation for Lavrentia soils SM2 % Second measurement of volumetric soil moisture at point The value is estimated based on Vitel readings by specific equation for Lavrentia soils SM3 % Third measurement of volumetric soil moisture at point The value is estimated based on Vitel readings by specific equation for Lavrentia soils