Net CO2 exchange, evaporation and heat flux data from Alice Holt plantation tower (1999-2012)

Net CO2, evaporation and heat flux data have been collected at the Alice Holt Flux tower since 1999, these data are used in combination with the data set ‘Meteorological and climatological data from the Alice Holt plantation tower (1999-2013)’ to examine the main drivers in inter-annual variation in CO2 fluxes at an oak forest in the south of England.
See also: Wilkinson, M., Eaton, E.L., Broadmeadow, M.S.J. and Morison, J.I.L. (2012). Inter-annual variation of carbon uptake by a plantation oak woodland in south-eastern England. Biogeosciences 9: 5373-5389.
The columns have the following definitions:
Label	Units, Format, or Range	Description
filename,-,Name of the raw file (or the first of a set) from which the dataset for the current averaging interval was extracted
date,yyyy-mm-dd,Date of the end of the averaging period
time,HH:MM,Time of the end of the averaging period
file_records,#,Number of valid records found in the raw file (or set of raw files)
used_records,#,Number of valid records used for current the averaging period
Tau,kg m-1 s-2,Corrected momentum flux
qc_Tau,#,Quality flag for momentum flux
rand_err_Tau,kg m-1 s-2,Random error for momentum flux, if selected
H,W m-2,Corrected sensible heat flux
qc_H,#,Quality flag for sensible heat flux
rand_err_H,W m-2,Random error for momentum flux, if selected
LE,W m-2,Corrected latent heat flux
qc_LE,#,Quality flag latent heat flux
rand_err_LE,W m-2,Random error for latent heat flux, if selected
gas_flux,µmol m-2 s-1(†),Corrected gas flux
qc_gas_flux,#,Quality flag for gas flux
rand_err_gas_flux,µmol s-1 m-2(†),Random error for gas flux, if selected
H_strg,W m-2,Estimate of storage sensible heat flux
LE_strg,W m-2,Estimate of storage latent heat flux
gas_strg,µmol s-1 m-2(†),Estimate of storage gas flux
gas_v-adv,µmol s-1 m-2(†),Estimate of vertical advection flux
gas_molar_density,mmol m-3,Measured or estimated molar density of gas
gas_mole_fraction,µmol mol-1(†),Measured or estimated mole fraction of gas
gas_mixing_ratio,µmol mol-1(†),Measured or estimated mixing ratio of gas
gas_time_lag,s,Time lag used to synchronize gas time series
gas_def_timelag,T/F,Flag: whether the reported time lag is the default (T) or calculated (F)
sonic_temperature,K,Mean temperature of ambient air as measured by the anemometer
air_temperature,K,Mean temperature of ambient air, either calculated from high frequency air temperature readings, or estimated from sonic temperature
air_pressure,Pa,Mean pressure of ambient air, either calculated from high frequency air pressure readings, or estimated based on site altitude (barometric pressure)
air_density,kg m-3,Density of ambient air
air_heat_capacity,J K-1 kg-1,Specific heat at constant pressure of ambient air
air_molar_volume,m3 mol-1,Molar volume of ambient air
ET,mm hour-1,Evapotranspiration flux
water_vapor_density,kg m-3,Ambient mass density of water vapor
e,Pa,Ambient water vapor partial pressure
es,Pa,Ambient water vapor partial pressure at saturation
specific_humidity,kg kg-1,Ambient specific humidity on a mass basis
RH,%,Ambient relative humidity
VPD,Pa,Ambient water vapor pressure deficit
Tdew,K,Ambient dew point temperature
u_unrot,m s-1,Wind component along the u anemometer axis
v_unrot,m s-1,Wind component along the v anemometer axis
w_unrot,m s-1,Wind component along the w anemometer axis
u_rot,m s-1,Rotated u wind component (mean wind speed)
v_rot,m s-1,Rotated v wind component (should be zero)
w_rot,m s-1,Rotated w wind component (should be zero)
wind_speed,m s-1,mean wind speed
max_wind_speed,m s-1,Maximum instantaneous wind speed
wind_dir,° (degrees),Direction from which the wind blows, with respect to Geographic or Magnetic north
yaw,° (degrees),First rotation angle
pitch,° (degrees),Second rotation angle
u*,m s-1,Friction velocity
TKE,m-2 s-1,Turbulent kinetic energy
L,M,Monin-Obukov length
(z-d)/L,#,Monin-Obukhov stability parameter
bowen_ratio,#,Sensible heat flux to latent heat flux ratio
T*,K,Scaling temperature
(footprint) model,-,Model for footprint estimation
x_offset,m,Along-wind distance providing <1% contribution to turbulent fluxes
x_peak,m,Along-wind distance providing the highest (peak) contribution to turbulent fluxes
x_10%,m,Along-wind distance providing 10% (cumulative) contribution to turbulent fluxes
x_30%,m,Along-wind distance providing 30% (cumulative) contribution to turbulent fluxes
x_50%,m,Along-wind distance providing 50% (cumulative) contribution to turbulent fluxes
x_70%,m,Along-wind distance providing 70% (cumulative) contribution to turbulent fluxes
x_90%,m,Along-wind distance providing 90% (cumulative) contribution to turbulent fluxes
un_Tau,kg m-1 s-2,Uncorrected momentum flux
Tau_scf,#,Spectral correction factor for momentum flux
un_H,W m-2,Uncorrected sensible heat flux
H_scf,#,Spectral correction factor for sensible heat flux
un_LE,W m-2,Uncorrected latent heat flux
LE_scf,#,Spectral correction factor for latent heat flux
un_gas_flux,µmol s-1 m-2(†),Uncorrected gas flux
gas_scf,#,Spectral correction factor for gas flux
spikes,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for individual variables for spike test
amp_res,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for individual variables for amplitude resolution
drop_out,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for individual variables for drop-out test
abs_lim,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for individual variables for absolute limits
skw_kur,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for individual variables for skewness and kurtosis
skw_kur,HFu/v/w/ts/co2 /h2o/ch4/n2,Soft flags for individual variables for skewness and kurtosis test
discontinuities,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for individual variables for discontinuities test
discontinuities,HFu/v/w/ts/co2 /h2o/ch4/n2,Soft flags for individual variables for discontinuities test
time_lag,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flags for gas concentration for time lag test
time_lag,HFu/v/w/ts/co2 /h2o/ch4/n2,Soft flags for gas concentration for time lag test
attack_angle,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flag for attack angle test
non_steady_wind,HFu/v/w/ts/co2 /h2o/ch4/n2,Hard flag for non-steady horizontal test
var_spikes,#,Number of spikes detected and eliminated for variable var
AGC,#,Mean value of AGC for LI 7500RS or LI 7200RS
RSSI,#,Mean value of RSSI for LI 7700, if present
var_var,-(‡),Variance of variable var
w/var_cov,-(‡),Covariance between w and variable var
extravar_mean,(‡),Mean value of extravar

The quality flags (e.g. qc_Tau) used are described on the following link. They range from 0 to 2; 0 is the best quality data and 2 the worst.

https://www.licor.com/env/help/eddypro/topics_eddypro/Flux_Quality_Flags.html?Highlight=quality%20flag 

Missing values are denoted with a -9999 Attribution statement: Forest Research must be acknowledged as the source of the data in any subsequent papers/products

Tags: England, Flux, Scientific, carbon, carbon dioxide, environment, evaporation, research
Organization: Forestry Commission