======================================================= Metadata file for SIZONet mass balance site near Barrow, Alaska 2013 ======================================================= Date: April 8, 2013 Updated: October 23, 2014 Author: Josh Jones (joshua.jones@gi.alaska.edu) Overview: ======== Date of deployment: January 15-18, 2013 Date of data collection: February 13, 2013 Date of radio deployment: April 1, 2013 Location: * Chukchi Sea, on landfast ice between Niksiuraq and Point Barrow * Latitude: 71.37056N * Longitude: 156.52596W * Relatively flat expanse of undeformed ice * Temperature at time of deployment: ~ -25C * Ice thickness: 0.86m Snow depth: 0.05cm Installed by: Josh Jones, Andy Mahoney, Megan O'Sadnick, Marc Oggier Project: SIZONet Phase II, NSF grant # 0856967 Features: ======== After encounters with polar bears last year, the decision was made to redesign the support system for the data logger box and other components where possible. Upgraded equipment include the CR1000 data logger, AM16/32B Multiplexor, 2GB Flash memory card, HMP155A air temperature and relative humidity sensors, 4 smaller batteries as new models of 85Ah batteries would not fit, and an SR50A from an old SR50. Replaced equipment include two other SR50A, CS107 water temperature probe, and CRREL-style thermistor strings. A new design to prevent slippage of the underwater pinger mast was installed, although the same Benthos PSA 916 underwater sounders were deployed. The same wind turbine was used as well, as the new wind turbine required a different size mast. Stainless steel frames were fabricated to be used to support the data logger boxes, instead of PVC frames. The radio equipment was also upgraded. The antenna at the mass balance site was replaced with another Yagi directional antenna. The radio at the mass balance site is now a Freewave FGR2-WC, replacing the FGR 115-WC. The transceiver located in the theater in Barrow, is now the Freewave FGR2-CE. The use of the new radio in the data logger box requires a null modem between RS-232 port on the CR1000 and the radio. The upgrade to the CR1000 from the CR10X required that a new program be written; the programming language changed between the two data logger models. The new language is much easier to read and write than the old CR10X language. Two differences between the old code and the new code, besides them being in different programming languages, is that the new code does not calculate temperature compensated distance from underwater sounders to bottom surface of ice or sea floor, and the processing of thermistor string resistance measurements into temperature happens on the data logger. Remote Site: =========== * Cables are protected from foxes by flexible metal conduit. As much as possible was recycled from the old mass balance equipment. * Data Logger: Campbell Scientific CR1000 AM/16/32B Multiplexor CFM100 Flash memory storage module * Data Link: Freewave FGR2-WC transceiver (Slave mode) Null modem Bluewave 10dB directional Yagi antenna * Batteries 4 Universal Battery UB12400 (12V 40Ah) in parallel * Thermistor String: CRREL type built in 2012 2 white PVC rods (~1.5m) containing 15 YSI type thermistors 10cm spacing between thermistors uppermost thermistor is 70cm above ice-snow interface * Under-ice Measurements Equipment attached to a dedicated mast going through the ice Ice thickness: upward looking Benthos PSA916, initial ice thickness=0.85m Water depth: downward looking Benthos PSA916, water depth during site selection=6.6-6.8m Water temperature: CS107 * Snow Depth Sounders SR50A (ID=0) above upward looking Benthos PSA916, 0.93m above ice surface, 0.09m snow SR50A (ID=1) about 10m northwest of data logger box, 1.01m above ice surface, 0.06m snow SR50A (ID=2) about 18m northwest of data logger box, 1.03m above ice surface, 0.04m snow * Air Temperature & Humidity Located on radio antenna mast, Shielded HMP155A * Wind Turbine: Aero4Gen, 12V, 100W Max LVM4SB12 temperature compensated charge controller, connected to batteries in parallel Base Station: =========== * Located at NARL, in the Theater * Data Link: Freewave FGR2-CE Bluewave 10dB directional antenna NPort 5110A-T serial device server * Virtual Machine: Data Acquisition and Processing: ========================== * File name of data logger program: BRW_MBS13_JAN15_900 * Data are acquired every 15 minutes as instantaneous measurements, except for the temperatures found by the thermistor strings. The thermistor string readings are averages of 20 readings taken in quick succession. * Snow depths, water depth, and ice thickness are calculated from distance measurements by the acoustic transducers SR50A and Benthos PSA916. Distances are temperature compensated with the HMP155A (air) and CS107 (water). Calculation of temperature compensated distance is performed on the CR1000 for the SR50A (snow depths), and performed at UAF in the processing steps for the Benthos PSA916 (water depth, ice thickness). Offsets are applied to the measurements to determine snow depth, ice thickness, and water depth in the processing steps at UAF. * The upgrade to the HMP155A allows for temperature measurements to -80C. The old CS500 only allowed for temperature measurements to -39.66C. * The thermistor strings measure voltage across a resistor, which are converted to temperatures with the Steinhart-Hart equation according to the manufacturer's specifications. T = -273.15 + 1/(0.0014661 + 0.00023857*ln((R)*1000)) + 0.00000010049*ln(((R)*1000))^3 where T is the temperature and R is R = 10*M/(1-M) and M is the measurement by the thermistor. Notes: ====== The data was not displayed on the Sea Ice Group's website for this ice season. Due to circumstances beyond our control, the data transmission between the Virtual Machine in Barrow and UAF could not be revived. The data was successfully collected on the Virtual Machine, as well as being stored on the flash card in the data logger, and was gathered periodically during field work campaigns. There was an issue with the processing of the thermistor string resistances on the data logger, and this was corrected after recovery of the MBS. File Format: ========== File Name: brw13_mbs_all.txt Format: ASCII, comma delimited Headers: 3 header lines 1 - Data logger name and information 2 - Column headers 3 - Data type (null) Invalid Values: 'NAN' Columns: 1 - Timestamp (YYYY-MM-DD HH:MM:SS) 2 - Record number 3 - Year 4 - Julian Day 5 - Hour 6 - Minute 7 - Data logger temperature 8 - Battery Voltage 9 - Water Temperature 10- Relative Humidity 11- Air Temperature 12- SR0 distance (0.93-SR0_meter=snow depth) 13- SR1 distance (1.01-SR1_meter=snow depth) 14- SR2 distance (1.03-SR2_meter=snow depth) 15- Underwater sounder distance, upward looking, not corrected for temperature dependent speed of sound in water 16- Underwater sounder distance, downward looking, not corrected for temperature dependent speed of sound in water 17- Topmost thermistor of thermistor string, temperature 70cm above ice surface 18- Second thermistor of thermistor string, temperature 60cm above ice surface ... 24- Thermistor at ice-snow interface, temperature at ice surface 25- Thermistor 10cm below ice-snow interface, temperature 10cm into sea ice 26- Thermistor 20cm below ice-snow interface ... 31- Thermistor 70cm below ice-snow interface 32- Thermistor 80cm below ice-snow interface ... 46- Thermistor 220cm below ice-snow interface