Processed atmospheric ceiling heights were recorded from a CT25K ceilometer. The instrument was mounted on the CCGS Amundsen icebreaker on the port side directly behind the ship's wheelhouse. Data were collected during transit, set transects, 24-hour stations, and multi-day drift stations. The instrument was running continuously during the IPY-CFL project, with only minor interruptions for maintenance activities.

This study is based on sampling conducted partially within the framework of the (1) Arctic Biological Station program-Biological Oceanography Section (ABS-BOS) from 1973 to 1975, (2) CCGS Sir Wilfrid Laurier program and CASES from 2002 to 2004, (3) IPY-CFL from 2007 to 2008, (4) through research collaborations among the CCGS Amundsen program, ArcticNet, BP Exploration Operating Company Limited, ExxonMobil and Imperial Oil from 2009 to 2011, and (5) BREA in 2012. Macrobenthos communities were sampled at 235 stations from 1973 to 2012 between April and November through different scientific programs and onboard different research vessels. Faunal samples were collected mostly with a USNEL box corer (0.25 m2), except from 1973 to 2002 where different grab models were used. Due to shared sediment requirements, on average 0.12 ± 0.05 m2 of sediment were sieved from each box core or grab sample. All box core and grab catches were washed under running seawater onboard over a 0.4 mm sieve during the CASES program and over a 0.5 mm sieve during all other programs, resulting in all macrobenthic invertebrates considered here being ≥ 0.5 mm size. Taxa were preserved in a 4 to 5 % seawater-formaldehyde solution buffered with sodium tetraethylborate for later identification in the lab and then transferred in 70 % ethanol for long-term storage.

The CTD data was obtained during the 2007-2008 scientific cruise #0802 within the framework of the Circumpolar Flaw Lead Study (CFL). This program included a year round sampling expedition to study the air-sea interactions occurring in the ice-free sections of the southern Beaufort Sea and Amundsen Gulf. The data were collected from March 15 to April 23, 2008, aboard the CCGS Amundsen. There were 132 CTD casts, associated to 10 ice-drift stations, located in the Amundsen Gulf area. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird SBE-9plus), dissolved oxygen (Sea-Bird SBE-43), pH (Sea-Bird SBE-18-I), fluorescence (Seapoint chlorophyll fluorometer), nitrate concentration (Satlantic MBARI-ISUS 5T), transmittance (Wetlabs C-Star transmissometer), light intensity (PAR; Biospherical Instruments QCP2300) and surface light intensity (sPAR; Biospherical Instruments QCP2200). Quality control procedures were applied to the data. Data are available on the Polar Data Catalogue and at the Marine Environmental Data Service (MEDS) of Fisheries and Oceans Canada.

The CTD data was obtained during the 2007-2008 scientific cruise #0708 within the framework of the Circumpolar Flaw Lead Study (CFL). This program included a year round sampling expedition to study the air-sea interactions occurring in the ice-free sections of the southern Beaufort Sea and Amundsen Gulf. The data were collected from December 22, 2007, to January 30, 2008, aboard the CCGS Amundsen. There were 158 CTD casts, associated to 10 ice-drift stations, located in the Amundsen Gulf area. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird SBE-9plus), dissolved oxygen (Sea-Bird SBE-43), pH (Sea-Bird SBE-18-I), fluorescence (Seapoint chlorophyll fluorometer), nitrate concentration (Satlantic MBARI-ISUS 5T), transmittance (Wetlabs C-Star transmissometer), light intensity (PAR; Biospherical Instruments QCP2300) and surface light intensity (sPAR; Biospherical Instruments QCP2200). Quality control procedures were applied to the data. Data are available on the Polar Data Catalogue and at the Marine Environmental Data Service (MEDS) of Fisheries and Oceans Canada.

The CTD data was obtained during the 2007-2008 scientific cruise #0801 within the framework of the Circumpolar Flaw Lead Study (CFL). This program included a year round sampling expedition to study the air-sea interactions occurring in the ice-free sections of the southern Beaufort Sea and Amundsen Gulf. The data were collected from February 2 to March 13, 2008, aboard the CCGS Amundsen. There were 139 CTD casts, associated to 10 ice-drift stations, located in the Amundsen Gulf area. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird SBE-9plus), dissolved oxygen (Sea-Bird SBE-43), pH (Sea-Bird SBE-18-I), fluorescence (Seapoint chlorophyll fluorometer), nitrate concentration (Satlantic MBARI-ISUS 5T), transmittance (Wetlabs C-Star transmissometer), light intensity (PAR; Biospherical Instruments QCP2300) and surface light intensity (sPAR; Biospherical Instruments QCP2200). Quality control procedures were applied to the data. Data are available on the Polar Data Catalogue and at the Marine Environmental Data Service (MEDS) of Fisheries and Oceans Canada.

Continuous measurements of emissivity at 89 and 37 GHz frequencies in vertical and horizontal polarizations at a fixed elevation angle of 55 degrees during transit and scanning elevation angles of 30-150 degrees at every station were acquired. The radiometers were installed at the 200 level on the CCGS Amundsen icebreaker on the port side. Generally the instruments acquired data at the fixed elevation angle during transit, and 3-5 scans were performed at every station along with auxiliary data collection (GPS data, geographic location of the station, photographs of the same field of view, air temperature, wind data, atmospheric conditions, surface characteristics, etc.). The acquired data are in binary format which is produced for every scan and fixed modes. The time in the data logger is generally set to UTC. An example filename would be 'RADDAT-2007-11-06-122647.DAT'.

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the near-surface atmosphere (basic meteorological elements, incident radiation, CO2 concentration) are monitored in conjunction with surface sea water properties (temperature, salinity, dissolved CO2 and O2) to observe the relationship between the surface micro-climate and the air-sea exchange, with particular interest in CO2. As part of this integrated dataset, the following radiation variables were recorded at 1 minute intervals (instrument used to collect each variable is in parentheses): -Incoming shortwave radiation (Eppley pyranometer, model PSP) -Incoming longwave radiation (Eppley pyrgeometer, model PIR) -Incoming photosynthetically active radiation (Kipp & Zonen, PAR-Lite) -Incoming UV-A radiation (Kipp & Zonen, UV-AB-T) - available after August 15, 2010 -Incoming UV-B radiation (Kipp & Zonen, UV-AB-T) - available after August 15, 2010 All instruments were mounted on a platform above the wheelhouse of the CCGS Amundsen

The all-sky camera system consists of a Nikon D-90 camera, with a wide-angle fish-eye lens, a homemade enclosure with clear acrylic dome end-cap, and a small heater on a thermostat. The system is mounted on a small 'crows nest' above the wheelhouse on the CCGS Amundsen. Maintenance checks were performed daily.

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the surface sea water (temperature, salinity, dissolved CO2 and O2) are monitored in conjunction with properties of the near-surface atmosphere (basic meteorological elements, incident radiation, CO2 concentration) to observe the relationship between the surface microclimate and the air-sea exchange, with particular interest in CO2. Central to this integrated dataset is an under-way sea water pCO2 system (General Oceanics 8050) attached to the ship's clean water intake. The following variables were measured continuously and logged at 1 minute intervals: -pCO2sw (LI7000 gas analyzer) -Equilibrator water temperature -conductivity -pH -dissolved O2

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the near-surface atmosphere (basic meteorological elements, incident radiation, CO2 concentration) are monitored in conjunction with surface sea water properties (temperature, salinity, dissolved CO2 and O2) to observe the relationship between the surface micro-climate and the air-sea exchange, with particular interest in CO2. Central to this integrated dataset, the following meteorological variables were recorded at 1 minute intervals (instrument used to collect each variable is in parentheses, and approximate instrument height above surface is indicated): -Wind speed (RM Young Wind Monitor 05103) - 16m height -Wind direction (RM Young Wind Monitor 05103) -16m height -Air Temperature (Vaisala HMP45C212) - 15m height -Relative Humidity (Vaisala HMP45C212) -15m height -Surface temperature (Apogee SI-111 Precision Infrared radiometer) - 8m height All instruments were mounted on a meteorological tower on the bow of the research icebreaker CCGS Amundsen.