A data set containing passive acoustic data from microphones, geophones and hydrophones placed on a frozen lake for 1 week. The experiment was conducted in February of 2024 on Portage Lake in the Upper Peninsula of Michigan, USA.The primary passive data is structured in 1-minute HDF5 files, each containing 8 or 11 channels of ambient ice fracture time series data recorded at 52100 Hz sample rate. The sensors were placed on/below ice ~254mm thick over water ~600mm deep. The secondary data set contains HDF5 files of in a similar structure to the first data set, but contain active impact responses in an array of locations around each acoustic sensor. Active impacts were created with a force hammer at a pre-determined set of impact locations around each acoustic array.

The expedition ARKTIS 1988 was initiated and directed by the Collaborative Research Centre 318 of the German Research Foundation entitled "Climatically relevant proceses in the system ocean-atmosphere-ice" and established at the University of Hamburg. The field experiment took place in the Fram Strait in the area straddling the ice margin west of Spitsbergen during the period from 4 to 26 May 1988. The experimental concept for the investigation of boundary layer modification and certain cloud structures in cases of off-ice and on-ice air flows was to maneuver one ship, the research icebreaker POLARSTERN, about 100 km into the ice and to operate with a second ship, the research vessel VALDIVIA, in the open water near the ice edge. Several aircraft operating from the airport at Longyearbyen on Spitsbergen were intended to measure the mean structures, variances and covariances at different distances from the ice edge. ARKTIS 1988 was followed by the two experiments ARKTIS 1991 and ARKTIS 1993.

The field experiment ARKTIS 1991 was an expedition planned by meteorologists of the Collaborative Research Centre 318 entitled "Climatically relevant processes in the system ocean-atmosphere-ice" which is funded by the German Research Foundation and established at the University of Hamburg. The expedition took place in the Norwegian Sea between Northern Norway, Bear Island and Jan Mayen during the period 17 February until 15 March 1991. The main aim of the experiment was the investigation of cold air outbreaks from the surrounding Arctic ice sheets. During such weather episodes the air mass coming from the ice is rapidly modified over the water due to the contrasts in temperature, heat conduction, humidity and roughness between ice and water. This leads to the formation of a "new" boundary layer. Its depth, mean temperature and moisture increases with increasing distance from the ice edge mainly due to sensible and latent heat supply from the ocean. The investigations of cold air outbreaks and Arctic stratus by scientists of the Collaborative Research Centre 318 began already three years before with the field experiment ARKTIS 1988 which took place in the area west of Spitsbergen in May 1988. ARKTIS 1991 is a continuation of this work under winterly weather conditions. ARKTIS 1991 was followed by the experiment ARKTIS 1993. As in ARKTIS 1988 the research vessel Valdivia and the two research aircraft FALCON-20 of the DLR at Oberpfaffenhofen and DO-128 of the TU Braunschweig were at our disposal. Radiosonde measurements were performed on board of RV Valdivia and on Bear Island.

The field experiment ARKTIS 1993 was the third one in a series of experiments in the Arctic region performed by a group of climate researchers from Hamburg. The campaign took place in the Greenland Sea west of Spitsbergen from 1 to 25 March 1993. The preceding experiments were ARKTIS 1988 (5 - 25 May 1988) in the same geographic region and ARKTIS 1991 (20 February - 13 March 1991) located between North Norway and Bear Island. The main objective of ARKTIS 1993 was the investigation of cold air outbreaks from the Arctic sea ice onto the open water, in this case the West Spitsbergen current. To get a concise picture of all stages of boundary layer modification in cold air outbreaks a wide variety of measurement platforms was employed. Three reseach vessels (Polarstern, Valdivia, Prof. Multanovsky) operated in the experimental area providing surface observations and radiosonde data. Aerological data was also collected at three land stations (Bear Island, Danmarkshavn, Ny Alesund) which intensified their operational radiosonde program. Most essential measurement were taken by the research aircraft Falcon and DO-128 which took profiles and cross sections within the air flow. Eleven flight missions were performed.

The field experiment DAMOCLES 2007 (Hamburg Arctic Ocean Buoy Drift Experiment DAMOCLES 2007-2008) consisted of the deployment and tracking of an array of 16 drifting autonomous buoys in the Central Arctic Ocean. The buoys were deployed in a quadratic array with 400 kilometres side length in the Siberian sector of the Central Arctic Ocean in April 2007. While drifting towards Fram Strait the buoys delivered at approximately 1-hourly time intervalls position, sea level pressure and temperature for several months with the last buoy transmitting until January 2008. The aim of the experiment was to study the Atmosphere-Ice-Ocean interaction, especially the impact of cyclones on the formation and transport of sea ice. DAMOCLES 2007 and DAMOCLES 2008 are a contribution to European integrated project DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies) which is funded by the European Union. DAMOCLES is a contribution to IPY 2007-2008 (International Polar Year).

The field experiment DAMOCLES 2008 (Hamburg Arctic Ocean Buoy Drift Experiment DAMOCLES 2008-2009) consisted of the deployment and tracking of 9 drifting autonomous ice buoys in the Arctic Ocean. Seven buoys were deployed in the Canadian sector of the Arctic Ocean in late April 2008. Two more buoys were deployed in the Beaufort Sea and in the Laptev Sea in September and October 2008. The platforms report position, atmospheric pressure, temperature and humidity, wind speed and ice temperature at 3-hourly time steps. The last two buoys additionally report wind direction. The aim of the experiment was to study the Atmosphere-Ice-Ocean interaction, especially the impact of cyclones on the formation and transport of sea ice. DAMOCLES 2008 and its predecessor DAMOCLES 2007 are a contribution to European integrated project DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies) which is funded by the European Union. DAMOCLES is a contribution to IPY 2007-2008 (International Polar Year).

The field experiment ARKTIS 1993 was the third one in a series of experiments in the Arctic region performed by a group of climate researchers from Hamburg. The campaign took place in the Greenland Sea west of Spitsbergen from 1 to 25 March 1993. The preceding experiments were ARKTIS 1988 (5 - 25 May 1988) in the same geographic region and ARKTIS 1991 (20 February - 13 March 1991) located between North Norway and Bear Island. The main objective of ARKTIS 1993 was the investigation of cold air outbreaks from the Arctic sea ice onto the open water, in this case the West Spitsbergen current. To get a concise picture of all stages of boundary layer modification in cold air outbreaks a wide variety of measurement platforms was employed. Three reseach vessels (Polarstern, Valdivia, Prof. Multanovsky) operated in the experimental area providing surface observations and radiosonde data. Aerological data was also collected at three land stations (Bear Island, Danmarkshavn, Ny Alesund) which intensified their operational radiosonde program. Most essential measurement were taken by the research aircraft Falcon and DO-128 which took profiles and cross sections within the air flow. Eleven flight missions were performed.

The expedition ARKTIS 1988 was initiated and directed by the Collaborative Research Centre 318 of the German Research Foundation entitled "Climatically relevant proceses in the system ocean-atmosphere-ice" and established at the University of Hamburg. The field experiment took place in the Fram Strait in the area straddling the ice margin west of Spitsbergen during the period from 4 to 26 May 1988. The experimental concept for the investigation of boundary layer modification and certain cloud structures in cases of off-ice and on-ice air flows was to maneuver one ship, the research icebreaker POLARSTERN, about 100 km into the ice and to operate with a second ship, the research vessel VALDIVIA, in the open water near the ice edge. Several aircraft operating from the airport at Longyearbyen on Spitsbergen were intended to measure the mean structures, variances and covariances at different distances from the ice edge. ARKTIS 1988 was followed by the two experiments ARKTIS 1991 and ARKTIS 1993.

The field experiment DAMOCLES 2007 (Hamburg Arctic Ocean Buoy Drift Experiment DAMOCLES 2007-2008) consisted of the deployment and tracking of an array of 16 drifting autonomous buoys in the Central Arctic Ocean. The buoys were deployed in a quadratic array with 400 kilometres side length in the Siberian sector of the Central Arctic Ocean in April 2007. While drifting towards Fram Strait the buoys delivered at approximately 1-hourly time intervalls position, sea level pressure and temperature for several months with the last buoy transmitting until January 2008. The aim of the experiment was to study the Atmosphere-Ice-Ocean interaction, especially the impact of cyclones on the formation and transport of sea ice. DAMOCLES 2007 and DAMOCLES 2008 are a contribution to European integrated project DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies) which is funded by the European Union. DAMOCLES is a contribution to IPY 2007-2008 (International Polar Year).