Sea Ice Group at the Geophysical Institute

Barrow Sea Ice Thickness and Sea Level

Barrow Sea Ice Mass Balance Site 2013

The Mass Balance Site was deployed between January 15-18, 2013. There were many improvements made to the set up and sensors that make up the site, and these are outlined below.

The Mass Balance Site's radios successfully sent the data to on-shore data bases, although the data transfer to Fairbanks from Barrow was not operational.

Overview

The Mass Balance Site consists of the following sensors:

in-ice thermistor string: temperatures at different positions above, through and below the ice
above-ice temperature/humidy sensor: air temperature and humidity
above-ice down-looking acoustic transducers: the position of the upper snow or ice surface
below-ice upward-looking acoustic transducer: the position of the ice bottom
below-ice down-looking acoustic transducer: local sea level at the Mass Balance Site
below-ice thermistor: water temperature

Ice thickness is calculated from the distance between the upper and lower surfaces of the ice.
In winter the positions of the upper and lower surfaces allow us to determine snow accumulation and ice growth, respectively.
In spring and summer, our measurements show the thinning that takes place from above and below.

Measurements are performed every 15 minutes and transferred to a base station in Barrow through a 900 MHz UHF radio link, from where they are sent through an internet connection to Fairbanks for further processing.

The data logger, rechargeable batteries, and all sensors (except for the below-ice acoustic transducers) were replaced for this season. All three above-ice acoustic transducers are now Campbell Scientific SR50As. The thermistor string is the same CRREL design used in the previous few Mass Balance Site deployments. The air temperature and relative humidity sensor has been upgraded from the Campbell CS500 to the Vaisala HMP155, which has a larger temperature range than the previous sensor. The water temperature probe, Campbell Scientific 107, was replaced with the same model. The CR10X data logger is no longer used, and has been replaced with the CR1000. This allows for the data to be backed up on a 4GB Flash card instead of Campbell's 16MB storage module. The previous batteries,two Exide 12V 85Ah, did not fit into the new data logger box, and are replaced with four FullRiver 12V 50Ah batteries. The new batteries are housed in the previous Mass Balance Site data logger box.

We are currently developing a user-friendly web application that will allow for easy download of plots based on the time period and MBS sensors needed. The processed 2013 MBS data can be found here: Chukchi Sea, all data (5.1 MB ascii)