CarboExtreme Database

Variables codes

Rules for variables names

In this page all the information needed to correctly report variables to the database are provided. To submit the data it is fundamental to use the correct variables names and units as reported in the table at the bottom of the page. However, in addition ot the variable name it is requested to use a 3 figures code which identifies univocally the location within the site where measurements are taken. The importance of this code is related to the possibility to associate to each variable a set of metadata like the method or instrument used, the measurement depth/height, the last calibration of the sensor etc.

Generally, the name of the variable has to be indicated as:


VAR= variable name (refer to the list of input variables)

The first figure stands for the position of the sensors on a 2D space. For instance, if soil temperature is measured at 3 different locations, these can be numbered as 1, 2, 3.







location 1


location 2


location 3


The second figure represents the vertical level (height above the ground/depth of the soil) of the sensors. Supposing to measure soil temperature at 3 different depths along a vertical profile at each location, then each variable can be identified as follows:








depth 1







depth 2







depth 3

location 1


location 2


location 3



Numeration increases moving downwards along a vertical profile but same number at two different locations can indicate different height/depth, that is specified in the metadata. So for example the deeper soil temperature measurement point in two different profiles of 4 sensors each will be indicated as Ts_1_4_1 and Ts_2_4_1 even if the first is at 80cm and the second 120cm below ground.

The third figure identifies the presence of replicated measurements in the same location. For instance, given 2 replicates of soil temperature measurements at position 1 and depth 1 (i.e. for sensors comparison), these would be indicated as:


Ts_1_1_1   Ts_1_1_2


Another example where the third figure should be used is for measurements at tree level like sap flow sensors. In this case the first figure indicate the tree (again specified in the metadata), the second the measurement height if you have for example sap flow measurements on the same tree at different heights and the third can be used to identify different sensors at the same height, commonly used in sap flow measurements.

Remember: All variables to be submitted must be characterized by the 3 figure code and in case of a variable being measured with a single sensor in a given point in space, the three figures of the code clearly equals 1.

New variables

We tried to consider all the common variables collected in the network also on the basis of what has been collected in previous projects. However new measurements are continuously added and it is possible that a variable to be submitted is not present in the “Variables codes”. In this case please contact the Databse Staff at the address and we will think together to the best solution. In any case do not send variables with names not consistent with those listed because these would be rejected by the system.

IMPORTANT: Additional information regarding the variables (height, depth) must be included in the metadata and not in the data file neither in the variable name. All additional information included in the data file are lost during the upload process.

Variables Codes List

Drag a column header and drop it here to group by that column
AG_BIOMASS_NWTAboveground biomass of non-woody plants. Dry weight of plants including plants and forbs. Grassland sites report the total above ground biomass. Forest sites report any non-woody plants.gC m-2 (ground)BADM1
AG_BIOMASS_STAboveground biomass of shrubs totalgC m-2 (ground)BADM2
AG_BIOMASS_TFAboveground biomass of tree foliage. Dry weight of live foliage.gC m-2 (ground)BADM3
AG_BIOMASS_TTAboveground biomass trees total. Dry weight live foliage, stems, and branches.gC m-2 (ground)BADM4
AG_BIOMASS_TWAboveground biomass of tree wood. Dry weight of live stems and branches.gC m-2 (ground)BADM5
AG_PROD_NWTAboveground production of non-woody plants. Dry weight of plants including plants and forbs. Grass sites report the total above ground biomass. Forest sites report any non-woody plants.gC m-2 (ground) y-1BADM6
AG_PROD_STAboveground production of shrub totalgC m-2 (ground) y-1BADM7
AG_PROD_TFAboveground production of tree foliage. Includes overstory foliage only.gC m-2 (ground) y-1BADM8
AG_PROD_TTAboveground production of tree total. Includes overstory foliage, stems, and branches.gC m-2 (ground) y-1BADM9
AG_PROD_TWAboveground production of tree wood. Includes overstory stems and branches.gC m-2 (ground) y-1BADM10
APARAbsorbed PAR (400-700 nm)umol m-2 s-1Database12
ASAMean stand age in yearsyearsBADM13
CH4Methane concentrationppb (nmol mol-1)Database14
CLAY_PERCClay content%BADM15
CO2CO2 concentrationppm (umol mol-1)Database16
CR_BIOMASSCoarse root biomass (live)gC m-2 (ground)BADM17
CR_PRODCoarse root productiongC m-2 (ground) y-1BADM18
dbh_dendDiameter at breast height (1.3m) from dendrometercmDatabase19
FcCO2 fluxumolCO2 m-2 s-1Database21
Fc_CMBNEE measured using transparent chambersumolCO2 m-2 s-1BADM or Database22
FCH4Methane (CH4) fluxnmol m-2 s-1Database23
FCH4_CMBMethane flux measured using chambersnmol m-2 s-1BADM or Database24
Fetch70Fetch at which footprint cumulated probability is 70%mDatabase25
Fetch90Fetch at which footprint cumulated probability is 90%mDatabase26
FetchmaxFetch at which footprint cumulated probability is maximummDatabase27
FN2ONitrous oxide (N2O) fluxnmol m-2 s-1Database28
FN2O_CMBN2O flux measured using chambersnmol m-2 s-1BADM or Database127
FNONO fluxnmol m-2 s-1Database29
FNO_CMBNO flux measured using chambersnmol m-2 s-1BADM or Database128
FNO2NO2 fluxnmol m-2 s-1Database30
FNO2_CMBNO2 flux measured using chambersnmol m-2 s-1BADM or Database129
FO3O3 fluxnmol m-2 s-1Database31
FR_BIOMASSFine root biomass (live)gC m-2 (ground)BADM32
FR_PRODFine root productiongC m-2 (ground) y-1BADM33
GSoil heat fluxW m-2Database34
GPP_piGross Primary Production (submitted by PI)umolCO2 m-2 s-1Database136
HSensible heat fluxW m-2Database35
H_piSensible Heat (submitted by PI)umolCO2 m-2 s-1Database133
H2OWater vapour concentrationppt (mmol mol-1)Database36
HEIGHTCCanopy heightmBADM37
LAILeaf Area Index. Averaged over the tower footprint. Calculated as m2 half-surface area leaf per m2 ground. Report green leaf LAI and not total leaf LAI.m2 m-2BADM38
LAI_UUnderstory Leaf Area Indexm2 m-2BADM39
LELatent heat fluxW m-2Database40
LE_piLatent heat (submitted by PI)umolCO2 m-2 s-1Database134
LeafwLeaf wetness%Database41
LIT_MASSLitter mass. Dry weight including litter and twigs < 1 cm diameter.gC m-2 (ground)BADM42
LIT_PRODLitterfall. Leaf litter and twigs < 1cm diameter. Sampled periodically through the year, dried and weighed and summed over yeargC m-2 (ground) y-1BADM43
LWinIncoming Longwave radiation (in the range from 4 to 50 micron)W m-2Database44
LWoutOutgoing Longwave radiation (in the range from 4 to 50 micron)W m-2Database45
MO_lengthMonin-Obukhov lengthmDatabase46
MWSMaximum wind speed m s-1Database47
NDVINormalized Difference Vegetation IndexadimensionalDatabase50
NEE_piNet Ecosystem Exchange (submitted by PI)umolCO2 m-2 s-1Database51
NetRadNet radiation (including SW and LW components)W m-2Database52
NONO concentrationppbDatabase53
NO2NO2 concentrationppbDatabase54
O3O3 concentrationppbDatabase55
P_snowSnowfall – snow precipitationmm (or water)Database58
PaAtmospheric pressureKPaDatabase59
PBLHPlanetary boundary layer heightmDatabase137
PPFDPhotosynthetic Photon Flux Density (400-700 nm)umol m-2 s-1Database60
PPFDbcBelow canopy PPFD (400-700 nm)umol m-2 s-1Database61
PPFDdDiffuse PPFD (400-700 nm)umol m-2 s-1Database62
PPFDrReflected PPFD (400-700 nm)umol m-2 s-1Database63
PRIPhotochemical reflectance indexadimensionalDatabase64
QcFcQuality check - CO2 flux - * see the noteadimensionalDatabase65
QcFCH4Quality check - Methane flux * see the noteadimensionalDatabase132
QcFootFootprint quality check: 0 if Fetch70 is outside the fetch or however to be discarded due to footprint issues, 1 if the data are okadimensionalDatabase66
QcHQuality check - sensible heat flux - * see the noteadimensionalDatabase67
QcLEQuality check - latent heat flux - * see the noteadimensionalDatabase68
QcTauQuality check - momentum flux - * see the noteadimensionalDatabase69
R_UVAUVA radiationW m-2Database70
R_UVBUVB radiationW m-2Database71
RautAutotrophic respiration fluxumolCO2 m-2s-1BADM or Database72
Raut_FMean autotrophic respiration from foliage (is continuous measurements please report using the database format)umol m-2 (ground) s-1BADM or Database73
Raut_RMean autotrophic respiration from roots (is continuous measurements please report using the database format)umol m-2 (ground) s-1BADM or Database74
Raut_WMean autotrophic respiration from wood (is continuous measurements please report using the database format)umol m-2 (ground) s-1BADM or Database75
Reco_piEcosystem Respiration (submitted by PI)umolCO2 m-2 s-1Database135
RHRelative humidity%Database76
RhetHeterotrophic respiration fluxumolCO2 m-2s-1BADM or Database77
ROCK_PERCRock content%BADM78
RsTotal respiration measured using chambersumolCO2 m-2s-1BADM or Database79
RT_BIOMASSTotal root biomass (live)gC m-2 (ground)BADM80
RT_PRODTotal root productiongC m-2 (ground) y-1BADM81
SaHeat storage in air below flux measurement levelW m-2Database83
SAND_PERCSand content%BADM84
Sap_dtDifference of probes temperature for sapflow measurements°CDatabase85
SapflowSapflowmmolH2O m-2 s-1Database86
SbHeat storage in biomassW m-2Database87
ScCO2 storage in air below flux measurement levelumolCO2 m-2 s-1Database88
Sigma_tsonicvariance of the sonic temperature°CDatabase139
Sigma_vStandard deviation of lateral velocity fluctuations (cross main-wind direction after coordinates rotation)m s-1Database89
Sigma_wStandard deviation of vertical velocity fluctuations m s-1Database90
SILT_PERCSilt content%BADM91
SNOWDSnow depthcmDatabase92
SOIL_CSoil organic carbon. Percent by m-2BADM93
SOIL_NSoil nitrogen contentkg m-2BADM95
SOIL_WATER_CAPSoil water holding capacitymmBADM96
Spec_in_529Incoming radiation at 529 nm umol m-2 s-1Database97
Spec_in_568Incoming radiation at 568 nm umol m-2 s-1Database98
Spec_nir_inIncoming radiation (infra-red band)umol m-2 s-1Database99
Spec_nir_outOutgoing radiation (infra-red band)umol m-2 s-1Database100
Spec_out_529Outgoing radiation at 529 nm umol m-2 s-1Database101
Spec_out_568Outgoing radiation at 568 nm umol m-2 s-1Database102
Spec_red_inIncoming radiation (red band)umol m-2 s-1Database103
Spec_red_outOutgoing radiation (red band)umol m-2 s-1Database104
SPP_OOverstory dominant speciesNRCS code or scientificBADM105
SPP_UUnderstory dominant speciesNRCS code or scientificBADM106
StemflowStem flowmmDatabase107
SwLatent heat storage below flux measurement levelW m-2Database108
SW_INIncoming Shortwave radiation (in the range from 0.3 to 4.5 micron)W m-2Database112
SWbcBelow canopy incoming short wave radiation W m-2Database109
SWCSoil water content%Database110
SWdifDiffuse incoming Shortwave radiation (in the range from 0.3 to 4.5 micron)W m-2Database111
SWoutOutgoing Shortwave radiation (in the range from 0.3 to 4.5 micron)W m-2Database113
T_DPDew Point Temperature°CDatabase140
TaAir temperature°CDatabase114
TauMomentum fluxKg m-2 s-1Database115
TbcAir temperature below canopy°CDatabase116
TboleBole temperature°CDatabase117
TcCanopy temperature°CDatabase118
TRTree transpirationml hr-1Database121
TsSoil temperature°CDatabase120
TsonicSonic Temperature°CDatabase138
ustarFriction velocitym s-1Database122
VPD_piVapour pressure deficit sent to PIhPaDatabase131
WDWind directionDecimal degreesDatabase123
WSWind speedm s-1Database124
WTDWater table depthcmDatabase125
ZLStability parameteradimensionalDatabase126

* note: for the quality flag definition please refer to this document: Quality Flags Definition