ISFS Variable Names
ISFS variable names and naming convention. Applicable to all ASTER/PAM/ISFF/ISFS projects.
 
Many meteorological variables are sampled using both slow response and fast response sensors. The slow response sensors provide a mean value for state variables, while fast measurements are used in eddy correlation calculations.

Names of slowly sampled variables (usually once per second or less) begin with an upper case character, for example P, T, RH, Dir, Spd, U, and V.

Lower case is used for more rapidly sampled (usually 10/sec or more) eddy correlation variables,for example: t, u, v, w, and q.

Derived fluxes use the abbreviation commonly used in the literature, which may be upper or lower case, for example, H for sensible heat flux.

Met Variables
Variable Name Full Name Usual Units Usual Source Notes
P
barometric pressure
mb
barometer
 
T
air temperature
degC
thermometer, TRH sensor
 
RH
relative humidity
%
hygrometer, TRH sensor
 
Td
dewpoint temperature
degC
 
 
Tw
wet bulb temperature
degC
 
 
Q
specific humidity
gr/kg of moist air
 
 
MR
water vapor
mixing ratio
gr/kg of dry air
 
 
Spd
wind Speed
m/s
prop vane or
2D sonic aneomometer
 
Dir
wind Direction
deg
prop vane or
2D sonic anemometer
0=from North,
90=East
Spdmax
maximum wind speed
m/s
 
 
U
U wind vector
component
m/s
prop vane or 2D sonic
+ is from West
V
V wind vector
component
m/s
prop vane or 2D sonic
+ is from South
 
Sonic Anemometer Winds
Variable Name
Full Name
Usual Units
Usual Source
Notes
u
U wind component
m/s
Sonic anemometer
may be in instrument, geographic or
special coordindate system
v
V wind component
m/s
"
"
w
W wind component
m/s
"
"
spd
wind speed
m/s
"
"
dir
ind direction
deg
"
0=along +u axis
diagbits CSAT3 diagnostic sum   CSAT3 Sonic anemometer sum of: 1(low signal),2(high signal), 4(no lock),
8(path difference),16(skipped sample)
ldiag CSAT3 logical diagnostic   CSAT3 logical value, 0=all diagbits are zero,
1=one or more non-zero diabits
Vazimuth
pointing direction (0=N,90=E)
of sonic +V axis
deg
hand held compass
 
uflag,vflag,
wflag,tcflag
sonic spikes
none
statistical analysis
fraction of points that are
detected as spikes
 
Fast Scalars
Variable Name
Full Name
Usual Units
Usual Source
tc
virtual Temp
degC
Sonic anemometer,
speed of sound
t
air Temperature
degC
Platinum wire
kh2o
water vapor density
gr/m^3
krypton hygrometer, not corrected for absorption by O2
h2o water vapor density gr/m^3 fast hygrometer
q
specific humidity
gr/kg of moist air
 
mr
water vapor
mixing ratio
gr/kg of dry air
 
co2mr
CO2 mixing ratio
ppmV
 
irgadiag diagnostic flag    EC150 H2O/CO2 infrared gas analyzer
o3mr
ozone mixing ratio
ppbV
 
Pcell, Pirga gas analyzer pressure mb Li7500, EC150; will have dynamic pressure error due to poor port placement
 
Eddy Correlation Covariances
Variable Name
Full Name
Usual Units
Usual Source
w't'
 
m/s degC
covariance of w with t from fast temperature probe
w'tc'
 
m/s degC
covariance of w with sonic temperature
w'q'
 
m/s gr/kg
 
w'h2o'
 
m/s gr/m^3
covariance of w with fast water vapor
w'kh2o'   m/s gr/m^3 Covariance of w with kh2o from krypton hygrometer, not corrected for absorption by O2
w'mr'
 
m/s gr/kg
 
w'co2mr'
 
m/s ppmV
 
w'o3mr'
 
m/a ppbV
 
 
Fluxes and Other Derived Quantities
Variable Name
Full Name
Usual Units
Usual Source
H
sensible heat flux
W/m^2
derived from sonic anemometer + gas analyzer
LE
latent heat flux
W/m^2
derived from sonic + gas analyzer
Gsfc
surface heat flux
W/m^2
derived from Gsoil, Tsoil, Csoil
L
Monin-Obukhov length
m
derived from sonic anemometer + gas analyzer
u*
friction velocity
m/s
derived from sonic anemometer
z/L
stability
 
derived from L
 
Radiation
Variable Name
Full Name
Usual Units
Usual Source
Notes
Rnet
net radiation
W/m^2
Q7
 
Rsw.in
incoming short
wave radiation
W/m^2
Pyranometer
 
Rsw.out
 
W/m^2
 
 
Rlw.in
incoming long
wave radiation
W/m^2
Pyrgeometer
Derived from Rpile.in, Tcase.in
Rlw.out
 
W/m^2
Pyrgeometer
Derived from Rpile.out, Tcase.out
Rpile.in
upward-looking
pyrgeometer thermopile
measurement
W/m^2
Pyrgeometer thermopile
Not corrected for sensor temperature
Rpile.out
downward-looking
pyrgeometer thermopile
W/m^2
Pyrgeometer thermopile
Not corrected.
Tcase.in
radiometer case
temperature
degC
thermistor
 
Tdome.in
radiometer dome
temperature
degC
thermistor
 
Tcase.out
 
degC
thermistor
 
Tdome.out
 
degC
thermistor
 
Rsw.sum
signed sum of
short wave
radiation
W/m^2
 
Rsw.in - Rsw.out
Rlw.sum
signed sum of
long wave radiation
W/m^2
 
Rlw.in - Rlw.out
Rsum
signed sum of
all radiation
W/m^2
 
Rsw.sum + Rlw.sum
Tsfc
surface temperature
degC
Everest
 
Rpar.in
 
 
Quantum
 
Rpar.out
 
 
 
 
Ruv.in
 
 
 
 
Ruv.out
 
 
 
 
Rveg
 
 
"veggie" meters
 
Wetness surface wetness indicator mV Decagon sensor can detect water source from shape of signal; flat=dry
 
Soil and Surface Variables
Variable Name
Full Name
Usual Units
Usual Source
Tsoil
soil temperature
degC
Presently, 4-prong NCAR-built probes
Qsoil
soil moisture
%vol
CS615, EC-20, EC-5 probes
Gsfc
heat flux at surface
W/m^2
Derived from Gsoil, Tsoil, Csoil
Gsoil
heat flux at at depth
W/m^2
REBS HFT
Vheat heater voltage V Hukseflux TP01
Vpile thermopile voltage microV Hukseflux TP01
asoil soil thermal diffusivity m^2/s Derived from TP01 Vheat, Vpile, Tau63
Tau63 soil heating time constant s Hukseflux TP01
Lambdasoil soil thermal conductivity W/m K Hukseflux TP01
Csoil soil heat capacity J/m^3 K Derived from TP01 asoil, Lambdasoil
Tice
ice temperature
degC
 
Gice
heat flux at at depth
W/m^2
 
Rain
Variable Name
Full Name
Usual Units
Usual Source
rainr, Rainr
rain rate
mm/hr
tipping bucket, Ott Parsival2
raina, Raina
rain accumulation
mm
derived from raina, Ott Parsival2
WX Present weather code   Ott Parsival2
Z Radar reflectivity (derived) dBz Ott Parsival2
Vis MOR visibility m Ott Parsival2
KE Particle kinetic energy J/m^2h Ott Parsival2
Sig Signal amplitude   Ott Parsival2
N Number of particles   Ott Parsival2
Stat Sensor status   Ott Parsival2
 
Engineering Variables
Variable Name
Full Name
Usual Units
Usual Source
Tbox
electronics temperature
degC
 
Vin, Vdsm power supply input voltage V  
Iin power supply current mA  
V3.3 Voltage to 3.3V supply V  
I3.3 current consumption of 3.3V supply mA  
Ixb current to Xbee radio mA  
I9x current to 9Xtend radio mA  
Isnsr current to sensor mA  
GPSnsat number of satellites acquired by GPS    
GPSstat status of GPS (1 is okay)    
Stratum status of time service (1 is best)    
Timeoffset error in data system clock us  
Ifan current consumption of TRH sensor's fan mA  

 

Full Format of ISFF Variable Names

If a variable is sampled at multiple locations at a site or with multiple sensors, additional fields can be appended to the variable names to make them unique. Adding additional fields to the variable names should only be done to keep the variables distinct. The instrument type, height and site should be documented elsewhere, rather than carried as excess baggage in the variable name. If possible, use simply "u" instead of "u.ati",or "u.ati.5m", or "u.ati.5m.flux".

Full format of variable names: variable [. sensor ][. height_depth ][. site ]

variable : conventional name for variable being measured, from tables above. Note that temperature measurements of substances other than air should have the substance in the measurement name, like Tsoil, Telec, so that it won't be confused with an air temperature.

sensor : (optional) use sensor name if measurement is not unique, e.g.: u.ati & u.gill.

height_depth : (optional) height or depth, e.g. 3m, 10m, 8cm. Use height if otherwise the name is not unique or if it helps clarify the name.

site : (optional) tower or site name. This is usually only needed if there are multiple towers at a station doing redundant measurements. In NetCDF files, variables from multiple stations will have a station dimension, rather than different names.

 

Names of Variances, Covariances and Higher Moments:

variance: varname'varname' u'u'
 
covariance: varname1'varname2' u'v'
 
How to combine long names into a covariance:
 
Covariance of "u.atik.3m" and h2o.csi.3m: u'h2o'.(atik,csi).3m
 
Covariance of "u.atik.3m" and h2o.3m: u'h2o'.(atik,).3m