Radiation, THP and soil sensor data location no. 16 in CASES99 network of flux towers version 1.0 1. Authors and data source: Wageningen University (the Netherlands) Oscar Hartogensis, Bas van de Wiel 2. Description of the sensors Some of the sensors used by Wageningen University described in this part were not initially planned in the experimental design. Russ Qualls from CU Boulder brought a surplus of sensors and dataloggers, which he made available to be used by Wageningen University. In the description of the sensors the addition “(Qualls)” will be used to indicate that these sensors were his. The fact that the use of these sensors was unplanned is the cause that initially there were some start up problems (power failures) resulting in incomplete data files. Also, the soils sensors were not available from the beginning of the experiment. An overview of data availability for the sensors described here are given in part 5. 2.1. Sensor types Radiation sensors: a. Kipp and Zn. CM14 albedometer; gives incoming and outgoing short-wave radiation b. Kipp and Zn. CG2 pyrgeometer; gives incoming and outgoing longwave radiation and the temperature (Pt100 sensors) of the top and down part of the instrument by means of which the internal longwave radiation emissions of the sensor itself can be corrected for. c. Everest 4000.4 GL Infra Red Thermometer (IRT) (Qualls) Temperature Humidity Probes (THP): 2 REBS THP_1 (Qualls); give temperature and relative humidity. Sensors are radiation shielded and ventilated. Soil sensors: 6 Pt100 soil thermometers built at Wagenigen University 1 TNO soil heat flux plate 1 REBS HFT3 soil heat flux plate (Qualls) 1 REBS STP soil temperature probe (Qualls) 1 REBS SMP1R soil moisture probe (Qualls) A Campbell Sci. 21X datalogger was used with an AM416 multiplexer and storage modules to store the data of all the sensors described above. 2.2 Specifications: Radiation sensors: a. CM14 albedometer: accuracy = +/- 2% off-set = +/1 10 W/m2 b. CG2 pyrgeometer: accuracy = +/- 10% off-set = 25 W/m2 The CG2 c. Infra Red Thermometer (IRT): off-set = +/- 0.5 K Temperature Humidity Probes (THP): No information available Soil sensors: TNO soil heat flux plate: - heat conductivity of plate = 0.25 W/mK - Diameter plate = 0.1 m - Thickness plate = 0.005 m REBS HTT3 soil heat flux plate: - heat conductivity of plate = 1.22 W/mK - Diameter plate = 0.3856 m - Thickness plate = 0.00393 m REBS SMP1R soil moisture probe: REBS supplies several calibrations for this sensor depending on soil type. Here the calibration for “clay loam” was chosen. 2.3 Location: Location no. 16 in CASES99 network of flux towers; co-ordinates N37’38.611’ W096’44.233’ 2.4 Set-up: Radiation sensors: Sensors were set up approximately 15 m south from the tower location 16. All sensors were mounted close together on a tri-pod at approximately 1.5 m height. The area the radiometers “see” was chosen to be as representative as possible for the area around tower 16, i.e. same distribution of grass and open patches. Temperature Humidity Probes (THP): The two sensors were mounted in the flux tower of location 16 at 7.65 m and 1.75 m. Soil sensors: The table given below describes the set-up of soil sensors used. In the first column the sensor type is given, in the second the vegetation type under which the sensor was put/buried together with the planned depth at which the sensor would be installed, in the last column the actual depth is given. Sensor Vegetation_setup exact depth (cm) Pt100 grass_0cm 0 Pt100 grass_1cm 0.5 Pt100 grass_3cm 2.8 Pt100 grass_8cm 7.8 Pt100 bare soil_0cm 0 Pt100 bare soil_1cm 0.8 SHF_TNO grass_5cm 5.4 SHF_REBBS grass_5cm 6.3 STP_REBS grass_3cm 2.6 SMP_REBS grass_3cm 2.7 Accuracy of measured depths is within +/- 0.3 cm. Note that the grass_0cm Pt100 was put right at the soil surface under the grass, the bare_0cm Pt100 was put on the bare soil without any shielding. 3. Description of derived variables Radiometers: a. CM14 albedometer: incoming and outgoing solar radiation were set to 0 W/m2 at night. This was done for both signals when either of them was smaller than or equal to 0 W/m2. b. The CG2 pyrgeometer: both incoming and outgoing radiation have been corrected for internal radiation exchange in the instrument with seperate temperature measurements for top- and down part of the instrument: L_corrected = L_measured + 5.6697E8 * T^4 [W/m2] Additionally, from the incoming and outgoing short-wave and longwave radiation the net radiation was calculated: Rnet = S_in - S_out + L_in - L_out [W/m2] Temperature Humidity Probes (THP): The THP itself outputs temperature and relative humidity only. The Campbell P56 instruction was used to online calculate the saturated vapour pressure, from which the water vapour pressure could be deduced. Soil sensors: The soil sensors have not been corrected in any way; e.g. the soil heatfluxes have not been corrected for difference in heat conductivity between the soil and the sensor, nor has a correction been made for heat storage in the thin soil layer above the sensor. 10 minute averaged data from all sensors were stored around the clock. For the 10 minute averaged data there are separate files for radiation, THP and soil sensors each containing all available data of the experiment. Apart from the 10 minute averages also 1 minute averaged data was stored from a selection of the available sensors between 17:00 and 9:00 local (CDS) time (only night time data) only. These are given in separate files per night, with the date (MMDD) given in the file name representing the start of the night. The columns in the data files are labelled; here follows an overview of all the variables with their label names and units: 10 minute radiation files: YYYYMMDDHHMMSS : Time in CASES99 standard time format [UTC] DOY : Day of Year [CDS] Time : Local time HHMM format [CDS] S_in : solar shortwave incoming radiation [Wm-2] S_out : reflected solar shortwave radiation [Wm-2] L_in : incoming longwave radiation [Wm-2] L_out : outgoing longwave radiation [Wm-2] Rnet : net radiation of incoming and outgoing shortwave and longwave radiation [Wm-2] IRT : infra red surface temperature [degC] 10 minute Temperature Humidity Probe (THP) file: YYYYMMDDHHMMSS : Time in CASES99 standard time format [UTC] DOY : Day of Year [CDS] Time : Local time HHMM format [CDS] Ta_up : air temperature at higher level (7.65m) [degC] Ta_down : air temperature at lower level (1.75m) [degC] RH_up : relative humidity at higher level (7.65m) [%] RH_down : relative humidity at lower level (1.75m) [%] Es_up : saturated vapor pressure at higher level (7.65m) [kPa] Es_down : saturated vapor pressure at lower level (1.75m) [kPa] e_up : water vapor pressure at higher level (7.65m) [kPa] e_down : water vapor pressure at lower level (1.75m) [kPa] 10 minute Soil sensors file: YYYYMMDDHHMMSS : Time in CASES99 standard time format [UTC] DOY : Day of Year [CDS] Time : Local time HHMM format [CDS] Pt_g0 : Pt100 temperature for grass at depth of 0 cm [degC] Pt_g1 : Pt100 temperature for grass at depth of approximately1 cm [degC] Pt_Rebs_g3 : Pt100 temperature for grass at depth of approximately 3 cm [degC] Pt_g3 : Pt100 temperature for grass at depth of approximately 3 cm [degC] Pt_g8 : Pt100 temperature for grass at depth of approximately 8 cm [degC] Pt_k0 : Pt100 temperature for bare soil at depth of 0 cm [degC] Pt_k1 : Pt100 temperature for bare soil at depth of approximately 1 cm [degC] SHF_TNO : soil heat flux with TNO sensor [Wm-2] SHF_Rebs : soil heat flux with Rebs sensor [Wm-2] SoilMoist : soil humidity expressed in mass water ratio (mass water / mass soil) [%] 1 minute night files of a selection of available radiation, THP and soil sensor data: YYYYMMDDHHMMSS : Time in CASES99 standard time format [UTC] DOY : Day of Year [CDS] Time : Local time HHMM format [CDS] L_in : incoming longwave radiation [Wm-2] L_out : outgoing longwave radiation [Wm-2] IRT : infra red surface temperature [degC] Ta_up : air temperature at higher level (7.65m) [degC] Ta_down : air temperature at lower level (1.75m) [degC] RH_up : relative humidity at higher level (7.65m) [%] RH_down : relative humidity at lower level (1.75m) [%] e_up : water vapor pressure at higher level (7.65m) [kPa] e_down : water vapor pressure at lower level (1.75m) [kPa] Pt_g0 : Pt100 temperature for grass at depth of 0 cm [degC] Pt_g1 : Pt100 temperature for grass at depth of approximately1 cm [degC] Pt_Rebs_g3 : Pt100 temperature for grass at depth of approximately 3 cm [degC] Pt_g3 : Pt100 temperature for grass at depth of approximately 3 cm [degC] Pt_g8 : Pt100 temperature for grass at depth of approximately 8 cm [degC] Pt_k0 : Pt100 temperature for bare soil at depth of 0 cm [degC] Pt_k1 : Pt100 temperature for bare soil at depth of approximately 1 cm [degC] 4. Sample period Sample period = 5s Averaging period = 10 minute data were stored around the clock, 1 minute averaged data were stored only for night time (between 17:00 and 9:00 local (CDS) time) The files are in plain ASCII text; the columns are space separated. 5. Data availability Availability of 10 minute averaged data: Since not all the data were available all of the time an overview is given here of when which systems were operational (indicated by an “x”) and when they were down (indicated by a “-“). It is only indicated when there has been a change in the situation. For example; between 09/30 16:50 and 05/10 11:30 there were only radiation data available, between 05/10 11:30 and 10/05 19:30 there were no data available, from 10/05 19:10 radiation and THP data and so on. Two nights were incomplete; the night from 10/08 to 10/09 and 10/15 to 10/16; these are indicated with a “(*)”. Time Radiation data THP data Soil sensor data (Date, Time (in CDS)) 09/30 16:50 x - - 10/05 11:30 - - - 10/05 19:30 x x - 10/06 10:10 - - - 10/06 10:10 x x - 10/06 12:50 - - - 10/06 20:10 x x - 10/07 12:20 - - - 10/07 14:00 x x - 10/08 13:50 (*) - - - 10/09 12:30 x x - 10/11 14:00 - - - 10/11 14:50 x x - 10/14 17:30 - - - 10/14 19:40 x x - 10/15 11:20 (*) - - - 10/16 3:50 x x x 10/16 15:10 - - - 10/16 18:20 x x x from 10/16 until the end of experiment on 10/28 all sensors were continuously were operational Availability of 1 minute averaged night data: 1 minute averaged night data are available between 1005 19:00 and 1028 10:00 local (CDS) time. As far as night time availability of the data the same table applies for the 1 minute as for the 10 minute data (see above). Thus two nights are incomplete: the night from 1008 to 1009 and 1015 to 1016.