TEXAS TECH UNIVERSITY STICKNET README last updated: 16 JUNE 2010 --------------------------------------------------------------------------------------------------------- This README file provides information concerning the Texas Tech University StickNet probe data sampling details and data structure. For more information please contact Dr. Chris Weiss at Chris.Weiss@ttu.edu --------------------------------------------------------------------------------------------------------- * MAXIMUM SAMPLING RATE * For probes ending in 'A', sampling rate can be toggled between 1 Hz and 5 or 10 Hz. For probes ending in 'B', the sampling rate is 1 Hz. The intent for most deployments is to sample at the maximum sampling rate possible. The sampling rate can be determined by looking at the timestamps within individual data files. Maximum sampling rate capabilities by platform are as follows: -->1 Hz 0102B 0104B 0106B 0108B 0214B 0216B 0218B 0220B 0222B 0224B -->5 Hz 0101A 0103A 0105A 0107A 0109A 0110A 0111A 0112A -->10 Hz 0213A 0215A 0217A 0219A 0221A 0223A --------------------------------------------------------------------------------------------------------- * DATA STRUCTURE * -->FILENAME Each file name depicts the probe ID, date and time (in UTC) of the start of data collection taken from an onboard GPS read at the time of deployment. If the GPS read is unsuccessful, this timestamp will be filled by zeroes. The format for the filename is: ID_DDMMYYY_HHMMSS. Sample: 0223A_17052009_164123 Probe: 0223A Date: 17 May 2009 Time: 16:41:23 UTC -->HEADER and FOOTER Each file will possess a header and footer providing time, position and orientation information. The header represents an initial GPS and compass read and the footer represents a GPS and compass read at the end of data collection. It has been found that the footer information is likely more accurate as the GPS has had more time to settle. It is recommended that the latitude, longitude and time information from the footer be used when available. Elevation information is also more likely to be available in the footer due to the time it takes the GPS to acquire the appropriate number of satellites to determine this. Electronic compass orientation is included in the header and is automatically incorporated into the wind direction data. If no compass value is acquired in the header, a value of '0' is assumed and incorporated into the wind direction data. ALL PLATFORMS ARE CONFIGURED SUCH THAT THE WIND SENSOR READS 0 DEGREES WHEN ALIGNED WITH THE COMPASS. Data users will need to consult archived deployment notes for platform orientation in the event a compass fails to report. The format for the header and footer is: ID,DDMMYYYY,HH:MM:SS,Latitude,Longitude,Elevation,Compass Sample: 0223A,17052009,16:41:23,38.8914,99.3214, 00614.4,190.2 Probe: 0223A Date: 17 May 2009 Time: 16:41:23 Latitude: 38.8914 (decimal degrees N) Longitude: 99.3214 (decimal degrees W) Elevation: 614.4 (meters) Compass: 190.2 (degrees) -->DATA The following units represent the data collected: TIME (HHMMSS.s UTC; HH - hour; MM - minute; SS - second; s - tenth of second) TEMPERATURE (C) RELATIVE HUMIDITY (%) BAROMETRIC PRESSURE (hPa) WIND SPEED (m/s) WIND DIRECTION (deg) ACCUMULATED RAINFALL (mm)* ACCUMULATED HAILFALL (hits/cm^2)* SUPPLY VOLTAGE (VDC)* * Rainfall, hailfall and supply voltage data are only available with 'B' Probes. Rainfall and hailfall data represent a running accumulation through the sampling period. The format for data collected by an 'A' probe is: HHMMSS.s,TEMP,RH,BP,WS,WD Sample for 'A' probe: 164147.3,19.9,23.3,951.8,5.2,203.9 Time: 164147.3 UTC TEMP: 19.9 C RH: 23.3 % BP: 951.8 hPa WS: 5.2 m/s WD: 203.9 deg The format for data collected by an 'A' probe is: HHMMSS,TEMP,RH,BP,WS,WD,RAIN,HAIL,VOLTAGE Sample for 'B' probe: 164129,20.1,24.5,951.6,5.8,205.7,0.00,0.0,18.1 Time: 164129 UTC TEMP: 20.1 C RH: 24.5 % BP: 951.6 hPa WS: 5.8 m/s WD: 205.7 deg RAIN: 0.00 mm HAIL: 0.0 hits/cm^2 VOLTAGE: 18.1 VDC --------------------------------------------------------------------------------------------------------- ***** UPDATES and NOTES ***** --------------------------------------------------------------------------------------------------------- -->We had significant issues with the VAISALA WXT520 ("all-in-one") sensor dropping wind measurements permanently during deployments. Probes using this instrument possess an ID that ends in 'B'. The cause of this was undetermined by Vaisala, but we speculate it had something to do with lightning. Through the project, we converted some of these probes to the 'A' variety (separate sensors). We also deployed 'B' probes even with a failed wind component because the thermodynamic data were still good. * After June 1, 2010, platforms 0104B and 0106B were converted to 0104A and 0106A, using instrumentation consistent with other 01XXA platforms sampling at 5 Hz. * After June 9, 2010, platform 0224B was converted to 0224A, using instrumentation consistent with other 02XXA platforms sampling at 10 Hz. -->Through (and including) the deployment of 6 June 2010 (this will include data collected in the 2009 campaign), it was discovered that probe 0107A had a grounding issue with the RMY Wind Monitor that was causing negative wind speed values to be reported, and possibly an overall degradation to the wind speed and direction data. It appears there was an overall low bias, but this bias may have varied by deployment, and even during an individual deployment. Users of data collected by this probe should exercise caution when using these data. ---------------------------------------------------------------------------------------------------------