Raw Eddy Correlation data; location no. 16; CASES99 experiment October, 1999 Readme belonging to CD numbers 1,2,3,4,5, & 6 of Wageningen University containing raw 10.2m height eddy correlation files in NetCDF. 1. Authors and data source: Wageningen University (the Netherlands) Oscar Hartogensis, Bas van de Wiel 2. Description of the sensors Eddy correlation system consisting of: a. Campbell Sci. CSAT3 sonic b. Campbell Sci. KH20 Krypton fast response hygrometer c. Campbell Sci. FW05 Thermocouple A Campbell 23X datalogger, which had two eddy correlation systems as described above (one at 10.2m and one at 2.65m) hooked up to it registered the data which was subsequently automatically downloaded onto to a laptop computer. Specifications: a. Campbell Sci. CSAT3 sonic: Path length over which the sensor integrates = 10 cm vertical, 5.8 cm horizontal Transducer Path Angle from Horizontal = 60 degrees Threshold = 30 mm/s for u and v; 4 mm/s for w b. Campbell Sci. KH20 Krypton fast response hygrometer Path length over which the sensor integrates = 1.4 cm Response time = 0.01s c. Campbell Sci. FW05 Thermocouple Diameter = 0.0005 inch Type = chromal - constantan Response time = better than 0.05s Location: Location no. 16 in CASES99 network of flux towers; co-ordinates N37'38.611' W096'44.233' Set-up: Height above the ground = 10.20m distance (horizontal) between Sonic and Krypton = 0.13m distance (horizontal) between Sonic and Thermocouple = 0.05m Directional off-set relative to North (0 deg) of Sonic = 65 degrees (+/- 5 degrees) Path length of Krypton = 0.014m Maintenance: The system was stopped during maintenance work on the tower. Every day the Krypton was cleaned with a moist Q-tip, thermocouple was checked and spider webs were removed. Once every two or three days the datalogger time was set to the GPS based time of the NCAR system within an accuracy of 1 second. 3. Description of variables in data set These are the variables in the raw eddy correlation files (in NetCDF) listed below with their units. The names given here are identical to those in the NetCDF files. "doy" units="days since 1999-01-01" long_name="day of year" type="short" "hour_min" units="-" type="short" ; time HHMM given in CDS (local) time "sec" units="-" ; time SS "u_hi" units="meter second-1" long_name="horizontal windspeed in x-coordinate" "v_hi" units="meter second-1" long_name="horizontal windspeed in y-coordinate" "w_hi" units="meter second-1" long_name="horizontal windspeed in z-coordinate" "Tsonic_hi" units="celsius" "diagnostic_hi" units="-" type="int" ; error code of the sonic; different errors have different error codes which added up form a diagnostic word from which individual errors can de deduced; in case of no errors the diagnostic word acts as a counter from 0 to 63. To conclude: only lines of data with a diagnostic value between 0 and 63 can be trusted. "Tcouple_hi" units="celsius" "Krypton_hi" units="mV" : calibration Rho_v = 59.53 - 9.118*ln(KH20_mV) + 0.25991*ln(KH20_mV)^2 units: [g/m^3] (valid for the path length of 0.014m used) NB1 The sonic data (u,v,w,Tsonic and diagnostic) lag exactly two samples behind the Krypton and Thermocouple data. NB2 From 30 Sept. until 20 Oct. the datalog system suffered overrun problems in writing the data to the PC; this means that effectively the system was not running on 20Hz; missed datalines can be detected in the diagnostic counter or the variable "Sec" (seconds) which skip a value from one line to the next when a data line was missed. From 1020 onward this problem was solved at the cost of not registering the Thermocouple data of the 10m eddy correlation system. NB3 invalid or no data are given as a dummy "-9999" 4. Sample period Sample period = 0.05s These are raw data files; no processing (averaging, calibration etc.) has been performed on data. 5. Raw eddy correlation data files on CD 1,2,3,4,5, & 6 from Wageningen University: The given begin- and end times are rounded to the nearest minute. Filename Begintime (CDS) End Time (CDS) yyyymmddhhmmss yyyymmddhhmmss (CD1:) EC10m_3009.nc 19990930175900 19991001130100 EC10m_0110.nc 19991001190800 19991002153600 EC10m_0210.nc 19991002174500 19991003160300 EC10m_0310.nc 19991003163100 19991004123000 EC10m_0410.nc 19991004180100 19991005112100 EC10m_0510.nc 19991005144200 19991006103700 EC10m_0610.nc 19991006130200 19991007123900 EC10m_0710.nc 19991007141600 19991008135300 EC10m_0810.nc 19991008141700 19991009120000 EC10m_0910.nc 19991009124100 19991010124200 EC10m_1010.nc 19991010134600 19991011173900 (CD2:) EC10m_1110.nc 19991011150400 19991012133200 EC10m_1210.nc 19991012135800 19991013172500 EC10m_1310.nc 19991013174200 19991014170000 EC10m_1410.nc 19991014170000 19991015112600 EC10m_1510.nc 19991015172700 19991016154700 EC10m_1610.nc 19991016155800 19991017132700 EC10m_1710.nc 19991017133700 19991018123000 EC10m_1810.nc 19991018140500 19991019114200 EC10m_1910.nc 19991019143500 19991020122200 EC10m_2010a.nc 19991020130100 19991020190300 (CD3:) EC10m_2010b.nc 19991020191100 19991021135300 EC10m_2110.nc 19991021140600 19991022132300 EC10m_2210.nc 19991022134000 19991023154400 EC10m_2310.nc 19991023162100 19991024134200 EC10m_2410.nc 19991024135000 19991025161200 EC10m_2510.nc 19991025163100 19991026112500 EC10m_2610.nc 19991026115100 19991027105900 EC10m_2710.nc 19991027111600 19991028091300 (CD4:) EC3m_3009.nc 19990930175900 19991001130100 EC3m_0110.nc 19991001190800 19991002153600 EC3m_0210.nc 19991002174500 19991003160300 EC3m_0310.nc 19991003163100 19991004123000 EC3m_0410.nc 19991004180100 19991005112100 EC3m_0510.nc 19991005144200 19991006103700 EC3m_0610.nc 19991006130200 19991007123900 EC3m_0710.nc 19991007141600 19991008135300 EC3m_0810.nc 19991008141700 19991009120000 EC3m_0910.nc 19991009124100 19991010124200 EC3m_1010.nc 19991010134600 19991011173900 (CD5:) EC3m_1110.nc 19991011150400 19991012133200 EC3m_1210.nc 19991012135800 19991013172500 EC3m_1310.nc 19991013174200 19991014170000 EC3m_1410.nc 19991014170000 19991015112600 EC3m_1510.nc 19991015172700 19991016154700 EC3m_1610.nc 19991016155800 19991017132700 EC3m_1710.nc 19991017133700 19991018123000 EC3m_1810.nc 19991018140500 19991019114200 EC3m_1910.nc 19991019143500 19991020122200 EC3m_2010a.nc 19991020130100 19991020190300 (CD6:) EC3m_2010b.nc 19991020191100 19991021135300 EC3m_2110.nc 19991021140600 19991022132300 EC3m_2210.nc 19991022134000 19991023154400 EC3m_2310.nc 19991023162100 19991024134200 EC3m_2410.nc 19991024135000 19991025161200 EC3m_2510.nc 19991025163100 19991026112500 EC3m_2610.nc 19991026115100 19991027105900 EC3m_2710.nc 19991027111600 19991028091300