• Energy Research

Solar radiation over and under sea ice was measured by an autonomous platform, installed on drifting sea ice in the Arctic Ocean during the SV TARA drift campaign in 2007 (station name 2007R24). The resulting time series describes radiation measurements as a function of place and time between 28 April 2007 and 05 September 2007 in sample intervals of 30 minutes. The radiation measurements have been performed with spectral radiometers. All data are given in full spectral resolution interpolated to 1.0 nm, and integrated over the entire wavelength range (broadband, total: 320 to 950 nm) and photosynthetically active radiation (PAR, 400 to 700 nm). Two sensors, solar irradiance and upward reflected solar irradiance, were mounted on a on a platform about 2 m above the sea ice surface. The third sensor was mounted 1.4 m underneath the sea ice measuring the downward transmitted irradiance. The data set has been processed and contains quality flags for different kinds for erroneous data. Flag values are the sum of individual error codes. The value of 0 refers to no error. Quality flag, sun: If the suns position is close to the horizon, the radiometers measure a very noisy signal. Radiometer measurements and variables which are computed from them are flagged +1 if the sun elevation is below 10 degrees; +2 if the broad band albedo exceeds the threshold 1.05 .

Solar radiation over and under sea ice was measured by an autonomous platform, installed on drifting sea ice in the Arctic Ocean during the SV TARA drift campaign in 2007 (station name 2007R24). The resulting time series describes radiation measurements as a function of place and time between 28 April 2007 and 05 September 2007 in sample intervals of 30 minutes. The radiation measurements have been performed with spectral radiometers. All data are given in full spectral resolution interpolated to 1.0 nm, and integrated over the entire wavelength range (broadband, total: 320 to 950 nm) and photosynthetically active radiation (PAR, 400 to 700 nm). Two sensors, solar irradiance and upward reflected solar irradiance, were mounted on a on a platform about 2 m above the sea ice surface. The third sensor was mounted 1.4 m underneath the sea ice measuring the downward transmitted irradiance. The data set has been processed and contains quality flags for different kinds for erroneous data. Flag values are the sum of individual error codes. The value of 0 refers to no error. Quality flag, sun: If the suns position is close to the horizon, the radiometers measure a very noisy signal. Radiometer measurements and variables which are computed from them are flagged +1 if the sun elevation is below 10 degrees; +2 if the broad band albedo exceeds the threshold 1.05 .

Solar radiation over and under sea ice was measured by an autonomous platform, installed on drifting sea ice in the Arctic Ocean during the SV TARA drift campaign in 2007 (station name 2007R24). The resulting time series describes radiation measurements as a function of place and time between 28 April 2007 and 05 September 2007 in sample intervals of 30 minutes. The radiation measurements have been performed with spectral radiometers. All data are given in full spectral resolution interpolated to 1.0 nm, and integrated over the entire wavelength range (broadband, total: 320 to 950 nm) and photosynthetically active radiation (PAR, 400 to 700 nm). Two sensors, solar irradiance and upward reflected solar irradiance, were mounted on a on a platform about 2 m above the sea ice surface. The third sensor was mounted 1.4 m underneath the sea ice measuring the downward transmitted irradiance. The data set has been processed and contains quality flags for different kinds for erroneous data. Flag values are the sum of individual error codes. The value of 0 refers to no error. Quality flag, sun: If the suns position is close to the horizon, the radiometers measure a very noisy signal. Radiometer measurements and variables which are computed from them are flagged +1 if the sun elevation is below 10 degrees; +2 if the broad band albedo exceeds the threshold 1.05 .

Solar radiation over and under sea ice was measured by an autonomous platform, installed on drifting sea ice in the Arctic Ocean during the SV TARA drift campaign in 2007 (station name 2007R24). The resulting time series describes radiation measurements as a function of place and time between 28 April 2007 and 05 September 2007 in sample intervals of 30 minutes. The radiation measurements have been performed with spectral radiometers. All data are given in full spectral resolution interpolated to 1.0 nm, and integrated over the entire wavelength range (broadband, total: 320 to 950 nm) and photosynthetically active radiation (PAR, 400 to 700 nm). Two sensors, solar irradiance and upward reflected solar irradiance, were mounted on a on a platform about 2 m above the sea ice surface. The third sensor was mounted 1.4 m underneath the sea ice measuring the downward transmitted irradiance. The data set has been processed and contains quality flags for different kinds for erroneous data. Flag values are the sum of individual error codes. The value of 0 refers to no error. Quality flag, position: The geographic position is flagged +1 if the drift velocity, as derived from the GPS longitude and latitude, exceeds a threshold of 10 deg latitude or 50 deg longitude per time step; +2 if the position exceeds extreme values, such as longitude > 360 deg; +4 if the position is exactly 0.0. Quality flag, sun elevation: If the suns position is close to the horizon, the radiometers measure a very noisy signal. Radiometer measurements and variables which are computed from them are flagged +1 if the sun elevation is below 10 degrees; +2 if the broad band albedo exceeds the threshold 1.05.

AbstractA large retreat of sea-ice in the ‘stormy’ Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently affected by passing winter storms. Here we synthesise the interdisciplinary N-ICE2015 dataset, including independent observations of the atmosphere, snow, sea-ice, ocean, and ecosystem. We build upon recent results and illustrate the different mechanisms through which winter storms impact the coupled Arctic sea-ice system. These short-lived and episodic synoptic-scale events transport pulses of heat and moisture into the Arctic, which temporarily reduce radiative cooling and henceforth ice growth. Cumulative snowfall from each sequential storm deepens the snow pack and insulates the sea-ice, further inhibiting ice growth throughout the remaining winter season. Strong winds fracture the ice cover, enhance ocean-ice-atmosphere heat fluxes, and make the ice more susceptible to lateral melt. In conclusion, the legacy of Arctic winter storms for sea-ice and the ice-associated ecosystem in the Atlantic Sector lasts far beyond their short lifespan.

This is chapter 6 of the State of Environmental Science in Svalbard (SESS) report 2019 (https://sios-svalbard.org/SESS_Issue2). Landfast sea ice (ice anchored to the shore) covers the inner parts of Kongsfjorden, Svalbard, in winter and spring, and is an important feature for the physical and biological fjord systems. Systematic fast-ice monitoring for Kongsfjorden, as a part of a long-term project at the Norwegian Polar Institute (NPI), started in 2003. It includes ice extent mapping and in situ measurements of ice and snow thickness. The permanent presence of NPI staff at Ny-Ålesund Research Station enables regular in situ fast-ice thickness measurements as long as the fast ice is accessible. In addition, daily visits to the observatory on the mountain Zeppelinfjellet close to Ny-Ålesund allow regular ice observations (weather, visibility, and daylight permitting). Monitoring of the sea ice conditions in Kongsfjorden can be used to demonstrate and investigate phenomena related to climate change in the Arctic. Fjord ice begins to form in the inner part of Kongsfjorden between December and March. After that the ice grows in thickness and extent, and then decreases until it melts or breaks off and drifts out of the fjord between April and June. Before 2006, ice often stretched from the interior to the central fjord parts, but in later years the ice has mainly been restricted to the inner fjord. Moreover, the ice was usually at least 0.6 m thick, in contrast to recent years with thickness often only about 0.2 m. The snow cover thickness on the ice in spring has also decreased, which can be partly explained by shorter fast ice seasons. The reason for less ice in Kongsfjorden after 2006 is considered to be a combination of the influence of warmer water and higher air temperatures in winter. This monitoring has contributed to a number of process and validation studies, for example to improve satellite remote sensing techniques and the understanding of atmosphere–ice–ocean interaction.