Updated 2022
ISFS variable names and naming convention. Applicable to all ASTER/PAM/ISFF/ISFS projects. Some additional parameters may be included based on the project needs.
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, spd.
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 | |
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 |
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 |
Tc | Sonic temperature | degC | 2D sonic |
3D 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 coordinate system |
v | V wind component | m/s | Sonic anemometer | May be in instrument, geographic or special coordinate system |
w | W wind component | m/s | Sonic anemometer | May be in instrument, geographic or special coordinate system |
spd | Wind speed | m/s | Sonic anemometer | May be in instrument, geographic or special coordinate system |
dir | Wind 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 |
Fast Scalar
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 | g/m^3 | Krypton hygrometer, not corrected for absorption by O2 |
h2o | water vapor density | g/m^3 | EC150 H2O/CO2 infrared gas analyzer or fast hygrometer |
co2 | carbon dioxide density | g/m^3 | EC150 H2O/CO2 infrared gas analyzer or fast hygrometer |
Tirga | CSI IRGA temperature | deg C | EC150 H2O/CO2 infrared gas analyzer |
irgadiag | diagnostic flag | EC150 H2O/CO2 infrared gas analyzer | |
Pcell, Pirga | Gas analyzer pressure | mb | Li7500, EC150; will have dynamic pressure error due to poor port placement |
Radiation Parameters
Variable Name | Full Name | Usual Units | Usual Source | Notes |
---|---|---|---|---|
Rsw.in | Incoming short wave radiation | W/m^2 | Pyranometer | |
Rsw.out | Outgoing short wave radiation | W/m^2 | Pyranometer | |
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 | Radiometer case temperature | degC | Thermistor | |
Rlw.in | Incoming long wave radiation | W/m^2 | Pyrgeometer | Derived from Rpile.in, Tcase |
Rlw.out | Outgoing long wave radiation | W/m^2 | Pyrgeometer | Derived from Rpile.out, Tcase |
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 | 4-prong NCAR-built probes |
Qsoil | Soil moisture | %vol | CS615, EC-20, EC-5 probes |
Gsoil | Heat flux at at depth | W/m^2 | REBS HFT |
Vheat | heater voltage | V | Hukseflux TP01 |
Vpile | thermopile voltage | microV | Hukseflux TP01 |
Tau63 | soil heating time constant | s | Hukseflux TP01 |
Lambdasoil | soil thermal conductivity | W/m K | Hukseflux TP01 |
Rain Parameters
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 |
Eddy Correlation Covariances
Variable 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'h2o' | m/s g/m^3 | Covariance of w with fast water vapor |
w'kh2o' | m/s g/m^3 | Covariance of w with kh2o from krypton hygrometer, not corrected for absorption by O2 |
w'co2' | m/s g/m^3 |
Names of Variances, Covariances and Higher Moments:
- variance: varname'varname'. Examples: u'u', h2o'h2o', P'P'
- covariance: varname1'varname2'. Examples: u'v', v'h2o', w'tc'
- 3rd order moments: varname1'varname2'varname3'. Examples: u'u'u', u'v'w', w'w'tc'
- How to combine long names into a covariance in a netcdf file:
- Covariance of h2o.3m and h2o.3m: h2o_h2o__.3m
- Covariance of w.3m and tc.3m: w_tc__.3m
- Covariance of u.3m, v.3m, and w.3m: u_v_w__.3m
Engineering Variables
Variable Name | Full Name | Usual Units |
---|---|---|
Iload, Icharge | Power supply current | mA |
Ifan | Current consumption of TRH sensor's fan | mA |
Vbatt, Vcharge, Vmote | Power supply input voltage | V |
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 |
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 |
Full Format of ISFS Variable Names
Full format of variable names: variable [_ site ] [_ height_depth ]
variable : conventional name for variable being measured, from tables above. Note that temperature measurements of substances other than air, or measured from a different sensor, should have the substance in the measurement name, like Tsoil, Tirga so that it won't be confused with an air temperature.
sensor : (optional) use sensor name if measurement is not unique, e.g.: u & u.gill
height_depth : (optional) height or depth, e.g. 3m, 10m, 3.1cm. 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.