# Calculation Notes

 Sensor Code: 5TM Sensor: 5TM from Decagon Devices Inc. Measurement: Volumetric water content (%) and Temperature (°C)
 Output 1: Apparent dielectric permittivity (unit-less) Range 1: 1 to 80 Output 2: Temperature (°C) Range 2: -40 to 50 Output 3: Range 3: 0 to 50

C8 soil calibration as provided by Decagon Devices on August 15, 2011.  Database uses coefficients A=17.8, B=40.9

 Sensor Code: MPS-2 Sensor: MPS-2 from Decagon Devices Inc. Measurement: Matric soil potential (kPa) and Temperature (°C)
 Output 1: Matric soil potential (kPa) Range 1: -5 to -500 Output 2: Temperature (°C) Range 2: -40 to 50
 Sensor Code: TCAV Sensor: TCAV from Campbell Scientific Inc. Measurement: Spatial average temperature (°C)
 Output 1: Temperature (°C) Range 1:-40 to 50
 Sensor Code: HFP-1 & HFP-1SC Sensor: HFP-1 & HFP-1SC from Hukseflux Inc. Measurement: Heat flux (Watts / m2)
 Output 1: Volts Range 1: -0.1 to 0.1 Output 2: Range 2: -2000 to 2000

Each sensor has its own calibration coefficient (k), see database. k is nominally 50μV / W / m
SC version of this sensor has control for an internal heater

 Sensor Code: GMM222 Sensor: GMM222 from Vaisala Inc. Measurement: CO2 Concentration (ppm)
 Output 1: Volts Range 1: 0 to 2.5 Output 2: Range 2: 0 to 5000, 0 to 7000 (depending on range)

k is either 5000ppm or 7000ppm

 Sensor Code: Model3130 Sensor: Model3130 from Honeywell International Inc. Measurement: Force (converted to mass in kg)
 Output 1: mV/V (unit-less) Range 1: -0.003 to 0.003 Output 2: Range 2: 0 to 2*108

Calibration coefficient, k, is the output at the rated MaxLoad (kip). For mass calculations: m=F/a, where a is 9.80665 (gravity) and 1 kip = 4448.2216 newtons (N)

 Sensor Code: Model41 Sensor: Model41 from Honeywell International Inc. Measurement: Force (converted to mass in kg)
 Output 1: mV/V (unit-less) Range 1: -0.003 to 0.003 Output 2: Range 2: 0 to 2*108

Calibration coefficient, k, is the output at the rated MaxLoad (lbs). The calibration parameters are provided to calculate lbs, therefore the conversion to kg requires 0.45359

 Sensor Code: EX81 Sensor: EX81P from Seametrics Inc. Measurement: Volume of flow
 Output 1: Pulses (unit count) Range 1: 0 to 1000000 Output 2: Range 2: 0 to ?
 Sensor Code: PE102 Sensor: PE102 from Seametrics Inc. Measurement: Volume of flow (Liters)
 Output 1: Pulses (unit count) Range 1: 0 to 600000 Output 2: Range 2: 0 to ?

For the "-075" model, k = 500 pulses per liter. For the low flow "-032" model, k = 1000 pulses per liter.

 Sensor Code: NovaLynx Sensor: 260-2501-A  from NovaLynx Measurement: Volume of flow (Liters)
 Output 1: Pulses (unit count) Range 1: 0 to 60 (per minute) Output 2: Range 2: 0 to ?

The rain gauge is designed to measure inches of rain at 0.01” per tip. When used as a flow meter, each tip corresponds to a specific volume of water. With an 8” input area this equates to 0.5024 cu. in. or 0.008237 liters of water.

k (rainfall) = 0.01”/tip,  k (volume) = 0.008237 liters/tip

The calibration parameter, k, is determined empirically.

 Sensor Code: TB Sensor: Any valid tipping bucket flow meter Measurement: Volume of flow (Liters)
 Output 1: Pulses (unit count) Range 1: Unspecified Output 2: Range 2: Unspecified

The rain gauge tipping bucket is designed to measure height of rain per tip. When used as a flow meter, each tip corresponds to a specific volume of water.

The calibration parameter, k, is determined empirically.

 Sensor Code:PTB110 Sensor: PTB110 from Vaisala Measurement: Barometric pressure (hPa)
 Output 1: Volts Range 1: 0 to 2.5 Output 2: Range 2: 500 to 1100

pmax and pmin refer to the range of the sensor. Vmax is the voltage at maximum calibrated pressure.

 Sensor Code: DeviceT Sensor: Onboard temperature measurement of any device given in degrees Celsius Measurement: Temperature (C)
 Output 1: Temperature (C) Range 1: unspecified
 Sensor Code: TC-x Sensor: Thermocouple of type “x” where “x” is any valid thermocouple type (E.g. E,K,T,…) Measurement: Temperature (C)
 Output 1: Temperature (C) Range 1: unspecified
 Sensor Code: Model81000VRE Sensor: Model 81000VRE from Young Company Measurement: Wind velocity and air characteristics
 Output 1: Speed (m/s) – air speed Range 1: 0 to 40 Output 2: Angle (degrees) -- direction Range 2: 0 to 360 Output 3: Angle (degrees) -- elevation Range 3: -60 to +60 Output 4: Speed (m/s) – speed of sound Range 4: 300 to 360 Output 5: Temperature (C) Range 5: -50 to 50
 Sensor Code: CSAT3 Sensor: CSAT3 from Campbell Scientific Measurement: Three component wind velocity and speed of sound
 Output 1: Ux (m/s) – air speed Range 1: -65.5 to 65.5 Output 2: Ux (m/s) – air speed Range 2: -65.5 to 65.5 Output 3: Ux (m/s) – air speed Range 3: -65.5 to 65.5 Output 4: Speed (m/s) – speed of sound Range 4: 300 to 366
 Sensor Code: HMP60 Sensor: HMP60 from Vaisala (sold by Campbell Scientific) Measurement: Relative Humidity, Temperature
 Output 1: Volts Range 1: 0 to 1 Output 2: Volts Range 2: 0 to 1 Output 3: Relative Humidity (%) = Output1 * 10 Range 3: 0 to 100% Output 4: Temperature (C) = Output2 * 100 - 40 Range 4: -40 to +60
 Sensor Code: DVI7911 Sensor: DVI7911 from Davis Instruments Measurement: Wind velocity and direction
 Output 1: Pulse count Range 1: unspecified Output 2: V/V (unit-less) Range 2: 0 to 1 Output 3: Average speed (m/s) = Output1 * k / T Range 3: unspecified Output 4: Direction (degrees) = Output2 * 360 Range 4: 0 to 360
 Sensor Code: SQ-110 Sensor: SQ-110 from Apogee Measurement: Photosynthetic photon flux
 Output 1: Volts Range 1: 0 to 0.8 Output 2: photon flux (µmol * m-2 * s-1) = Output1 * k Range 2: 0 to 4000
 Sensor Code: CS451 Sensor: CS451 from Campbell Scientific Measurement: Pressure (water level)
 Output 1: Pressure (PSI) Range 1: 0 to 2.9 Output 2: Temperature (C) Range 2: 0 to 60 Output 3: Water level (cmH2O) = Output1 * 70.307 + offset Range 3: 0 to 200

The value of "offset" is determined empirically

 Sensor Code: T4 / T4E Sensor: T4 / T4E from Umwelt Monitoring Systems (UMS) Measurement: Soil water tension
 Output 1: Volts Range 1: -0.1 to 0.085 Output 2: Tension (kPa) = Output1 * (-1000) + offset Range 2: -85 to 100
 Sensor Code: CNR4 Sensor: CNR4 from Kipp-Zonen (sold by Campbell Scientific) Measurement: Global and reflected radiation intensity
 Output 1: Volts Range 1: 0 to 0.015 Output 2: Volts Range 2: 0 to 0.015 Output 3: Volts Range 3: -0.005 to 0.005 Output 4: Volts Range 4: -0.005 to 0.005 Output 5: Resistance Range 5: 80 to 130 Output 6: Incoming shortwave intensity (Watts/m^2) = Range 6: 0 to 1000 Output 7: Outgoing shortwave Intensity (Watts/m^2) = Range 7: 0 to 400 Output 8: Temperature (K) = Range 8: 220 to 335 Output 9: Incoming long wave intensity (Watts/m^2) = Range 9: -150 to 0 Output 10: Outgoing long wave intensity (Watts/m^2) = Range 10: -25 to 25

ka, kb, kc, and kd are the four calibration coefficients assumed to be in microvolts per W/m^2

Pt-100 RTD has a temperature relation approximated by theCallendar-Van Dusen equation. A =3.908x10^-3; B = -5.8019*10^-7; C = -4.2735*10^-12; Ro = 100; for the DIN standard RTD used in the CNR4.
Temperature formula is only valid for T > 272.15 (K)
A numeric approximation is used for T < 272.15 (K)

 Sensor Code: VW-PZO Sensor: GEO-VW-PZO from Geo-Instruments LLC Measurement: Pressure (PSI - converted to cmH2O)
 Output 1: Frequency (Hz) Range 1: 2000 to 6000 Output 2: Resistance (ohm) Range 2: 2000 to 4000 Output 3: Pressure (cm H2O) Range 3: 0 to 120

The calculations required to determine pressure are as follows:     Sensor Code: WTW340 Sensor: WTW340 from WTW Measurement: Electrical conductivity (µS/cm)
 Output 1: Voltage Range 1: 0 to 5 Output 2: Conductivity (micro-siemens / cm) Range 2: Unspecified
 Sensor Code: VALWORX Sensor: VALWORX Ball Valve Measurement: Valve state
 Output 1: Valve State Range 1: 1, 0, -1, -9999

The valve contains two SPST-NO relays. One relay is used to indicate an open valve, and the other is used to indicate a closed valve.
The output logged to the database is determined by the table below.

Open RelayClosed RelayIndicated State
0 (Low)0 (Low)0 (Unknown/Transition)
1 (High)0 (Low)1 (Open)
0 (Low)1 (High) -1 (Closed)
1 (High)1 (High)-9999 (Inconsistent)
 Sensor Code: LI7000 Sensor: LI-COR LI-7000 Measurement: CO2 & H2O concentration
 Output 1: Cell A CO2 Concentration (umol/mol) Range 1: 0-3000 Output 2: Cell B CO2 Concentration (umol/mol) Range 1: 0-3000 Output 3: Cell A H2O Concentration (mmol/mol) Range 2: 0-60 Output 4: Cell B H2O Concentration (mmol/mol) Range 1: 0-60 Output 5: Cell B Pressure (kPa) Range 1: 0-115 Output 6: IRGA Temperature (C) Range 1: 0-3000
 Sensor Code: SurfaceHeatFlux Sensor: Computed data from 5TM, TCAV, and HFP-1/SC Measurement: Heat flux (Watts / m2)
 Output 1: Heat flux at surface for HFP-1 (Watts/m2) Range 1: -2000 to 2000 Output 2: Heat flux at surface for HFP-1SC (Watts/m2) Range 2: -2000 to 2000 Output 3: Average surface heat flux (Watts/m2) Range 3: -2000 to 2000

Moist soil heat capacity:  = bulk density (For LEO this is  1570 kg/m3) = density of water (999 kg/m^3) = the volumetric water content (decimal 0.0 to 0.5)
Cd = heat capacity of dry soil (0.89 kJ/kg/K)
Cw = heat capacity of water (4.179 kJ/kg/K)

Storage term  = change in soil temperature
d = depth
t = output interval

Soil heat flux at the surface, Tags:

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