---------------------------------------------------- Metadata for UAF Sea Ice Mass Balance Site 2006 ----------------------------------------------------- Daniel Pringle pringle@gi.alaska.edu ----------------------------------------------------- Patrick Cotter and Daniel Pringle installed the site with assistance from BASC staff Henry Gueco and Scott Oyagak, January 31 – February 2, 2006. Site location, GPS: (71° 22' 03" N, 156° 31' 03" W). The site is about 300 m offshore on the Chukchi Sea side of the spit about half way between the end of the road and Pt. Barrow proper. We crossed a low point in the beach ridging caused by an ivu the previous week earlier. The following measurements are recorded: (i) snow and ice thickness and local sea level; (ii) temperature profile through air-snow-ice-water; (iii) air temperature and relative humidity at 2m above the ice; NB: Hydraprobes malfunctioned in 2006, with no data recovery. Mass Balance Site: Campbell CR10X Data logger, AM1664 multiplexer, SM4M storage module, SC32A adaptor. FreeWave Spread-spectrum, no-license radio: FGR 115-WC, 900 MHz Bluewave 10 dB directional Yagi Antenna (BMY890K). Campbell SR50 Sonic Ranger (snow pinger), Shielded 107 air temperature probe, Benthos underwater acoustic altimeter PSA-916 (one upward looking, one downward looking), CRREL-design thermistor strings (3 x 1 meter sections), UAF dielectric array: 3 Vitel Water Hydraprobes. Batteries: 2 (of 4 total) UAF 12V cells currently stored at BASC (85 Amp-hr Exide). BASC Site: Bluewave 10 dB omni-directional Antenna and RF coaxial cabling to: FreeWave Spread-spectrum, no-license radio: FGR 115-RC, 900 MHz, connected to the serial port of a dedicated control PC with an internet connection. ----------------------------------------------------- Measurement intervals: The measurement interval was originally 30 minutes, but this was changed to 1 minute (to potnentially observe high frequency motion during the spring),and then to 5 minutes (to conserve battery life). Two data sets are available: the full one, and one down-sampled to only give half-hourly measurments. ----------------------------------------------------- Listed below are examples of the entries in each column in the data files. Notes: (i) All depths are referenced to the ice/water interface at the time of installation. (ii) T107 water temp is used by the data logger program to calculate the underwater depths using a speed of sound, vs,water = ... Similarly, the snow pinger uses a correction from the air temperature measurement, vs,air = .. (This shielded sensor at 2.25 m above ice/snow interface bottoms out at – 39.67 C). (iii) Time* is the time as day of year in a decimal format, here 11:00 am on day 75 (March 16, 2006 ) gives 75.45833 (iv)The reference resistor is a low-temperature co-efficient resistor. Its variability indicates the noise in the temperature measurements. ----------------------------------------------------- Quality: These data have been processed to compute the physical values from the measured quantities. Periods of 'bad' data have been removed. However the time-series is not complete due to battery failure, and intermittent 'bad' values are returned. Plotting time-series as points not lines at least during inspection is recommended. ----------------------------------------------------- Column Description Value 1 Time* (decimal) 36.75 2 year 2006 3 day 36 4 time (hhmm) 1800 5 logger temp [C] -26.4 6 bat volts [V] 11.74 7 T107 water temp [C] -1.855 8 CS500 rel hum [%] 74.2 9 SC500 air temp [C] -26.88 10 snow depth [m] 0.1372 11 ice thickness [m] 0.8716 12 sea level [m] 6.3218 13 Ref. ref equiv.temp [C] -5.8986 14 T1 (+40 cm) [C] -26.8946 15 T2 (+30 cm) [C] -26.8725 etc … … … … 42 T29 (-240 cm) [C] -1.7422