Air-Deployed Microbuoy Measurement of Temperatures in the Marginal Ice Zone Upper Ocean during the MIZOPEX Campaign

Abstract

ir-deployed microbuoys (ADMBs) were developed as a means of measuring subsurface temperatures in the marginal ice zone (MIZ) over campaign-duration time scales to better understand how MIZ surface layer heat content accelerates melt rates at the edge of the ice pack. ADMBs are small, low-cost buoys deployable from unmanned aircraft and are capable of measuring temperatures to 0.1°C absolute accuracy at the surface, 1-m, and 2-m depth, along with GPS position. Each ADMB contains a microcontroller, GPS, 900-MHz radio, flash electrically erasable programmable read-only memory (EEPROM), battery, and a set of temperature sensors to monitor conditions for up to 10 days. A communications board on an overflying aircraft autonomously deploys each ADMB and collects data from previously deployed ADMBs for analysis. The 2013 Marginal Ice Zone Observations and Processes Experiment (MIZOPEX) campaign deployed ADMBs into the summer melt season MIZ north of Oliktok Point, Alaska, collecting over 400 h of data from two clusters of buoys during the short field campaign. Initial results indicate that SST is a good measure of upper-ocean temperature in the MIZ when conditions are well mixed, but that is often not the case. In areas with higher ice concentration, surface temperatures tend to underestimate the temperature of the subsurface, while in areas of low ice concentration, SSTs overestimate the subsurface temperature.