ALBERT

Description: The data contain ten horizontal fields of cloud optical thickness, retrieved from airborne measured reflected solar spectral radiance at 550 nm wavelength. The data were obtained during the airbone VERtical Distribution of Ice in Arctic clouds (VERDI) campaign based at Inuvik, North West Territories, Canada between 17 April and 17 May 2012. The applied fields of reflected solar spectral radiance were measured with the imaging spectrometer AisaEAGLE (36.3° field of view, 467 spatial pixels, 400-970 nm wavelength range) mounted on the Polar 5 research aircraft of the Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.

Description: Polar 6 conducted a systematic digital photographic aerial survey of the area of the Atka Bay from Neumayer Station on 04 January 2018. The total survey distance covered 1,232 km. The survey covered the western contour and central bay area but was not extended to the eastern Bay contour since no seals were seen on the bay ice in this area. At the same time, a WorldView 3 satellite image (Ortho Ready Standard 4 band Pansharpened NC and Panchromatic channels) was taken with minimal time deviation relative to the aircraft survey.

Description: Most permafrost is located in the Arctic, where frozen organic carbon makes it an important component of the global climate system. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low. Permafrost thaw and carbon release to the atmosphere are a positive feedback mechanism that can exacerbate climate warming. This positive feedback functions via changing land-atmosphere energy and mass exchanges. There is thus a great need to understand links between the energy balance, which can vary rapidly over hourly to annual time scales, and permafrost, which changes slowly over long time periods. This understanding thus mandates long-term observational data sets. Such a data set is available from the Bayelva Site at Ny-Ålesund, Svalbard, where meteorology, energy balance components and subsurface observations have been made for the last 20 years. Additional data include a high resolution digital elevation model and a panchromatic image. This paper presents the data set produced so far, explains instrumentation, calibration, processing and data quality control, as well as the sources for various resulting data sets. The resulting data set is unique in the Arctic and serves a baseline for future studies. Since the data provide observations of temporally variable parameters that mitigate energy fluxes between permafrost and atmosphere, such as snow depth and soil moisture content, they are suitable for use in integrating, calibrating and testing permafrost as a component in Earth System Models. The data set also includes a high resolution digital elevation model that can be used together with the snow physical information for snow pack modeling.

Description: An 8,000-year lacustrine sediment record from Lake Motosu (Fuji Five Lakes) records several eruptions, including potentially unreported events, of the active Mt. Fuji volcano, which receives approximately 47 million annual visitors. A high-fidelity age model is constructed from tephra ages and high-density radiocarbon dating of terrestrial macrofossil and bulk organic matter. Variability in lake reservoir age is constrained by modern lake water radiocarbon measurement and reverse calibration of tephra calendar ages. We present more accurate ages for known eruptions, detect a wider distribution of ejecta for the most recent summit eruption, and potentially identify previously undetected flank eruptions. There are closely spaced scoria-fall layers that may be difficult to differentiate as separate events in land-based surveys. These results demonstrate the utility of lacustrine sediments as powerful tools for understanding characteristics of volcanic eruptions.

Description: Raw data acquired by GPS1 position sensors on board research aircraft Polar 5 during the campaign P5_223_MOSAiC_ACA_2020 were processed to receive a validated master track which can be used as reference of further expedition data.Novatel FlexPak6 GPS receiver was used as navigation sensors during the campaign. Data were downloaded from DAVIS SHIP data base (https://dship.awi.de) with a resolution of 1 sec. Processed data are provided as a master track with 1 sec resolution and a generalized track with a reduced set of the most significant positions of the master track. A detailed report on processing is also available for each flight.

Description: Data presented here were collected between January 2020 to December 2020 within the research unit DynaCom (Spatial community ecology in highly dynamic landscapes: From island biogeography to metaecosystems, https://uol.de/dynacom/ ) of the Universities of Oldenburg, Göttingen, and Münster, the iDiv Leipzig and the Nationalpark Niedersächsisches Wattenmeer. Experimental islands and saltmarsh enclosed plots were created in the back barrier tidal flat and in the saltmarsh zone of the island of Spiekeroog. Temperature in the sediment surface layer (in approximately 0.05m depth) was measured with DEFI-T miniature temperature recorders (JFE Advantech Co., Ltd., Tokyo; DEFI-T). The manufacturer pre-calibrated temperature recorders and were installed on the experimental islands and in salt-marsh enclosed plots at different elevation levels. Recorded data were internally logged until the readout with the DEFI Series software (V1.02). The position was derived from a portable DGPS-system. Date and Time is given in UTC. Data handling was performed according to Zielinski et al. (2018): Post-processing of collected data was done using MATLAB (R2018a). Quality control was performed by (a) erasing data covering maintenance activities, (b) removing outliers, defined as data exhibiting changes of more than two standard deviations within one time step, and (c) visually checks.

Description: High resolution aerial images in the RGB, near infrared and thermal infrared obtained during the 2020 IceBird MOSAiC Summer campaign using the research aircraft POLAR 6. Data was gathered during three flights from Longyearbyen, Svalbard over sea ice in the western and northern Fram Strait on September 02, 07, and 08, 2020.

Description: Here, we compiled data obtained from a research cruise with the German RV Meteor (M153) and an oceanographic mooring to demonstrate that a nutrient trapping zone develops in a narrow belt along the coast during the main upwelling season in the southern Benguela Upwelling System (SBUS). It modifies links between the strength of upwelling, productivity and the intensity of the oxygen minim zone (OMZ) in the SBUS. During the cruise M153 shipboard measurements were conducted along a station grid in the SBUS between February 16th and 28th, 2019. This included CTD casts, one TRIAXUS transect and the deployment of one mooring equipped with a Mini Dot Oxygen Sensor (MDO) and Hydrobios MST-12 sediment trap at water-depth of approximately 95.5 m. In order to study the diurnal cycle, four CTD casts were conducted between February 18th and 19th at station 7 close to the mooring location while mooring data and publically available satellite data on sea surface temperature and primary production were used to study the seasonal cycles of the nutrient trapping zone.

Description: Raw data acquired by GPS1 position sensors on board research aircraft Polar 5 during the campaign P6_222_IceBird_MOSAiC_2020 were processed to receive a validated master track which can be used as reference of further expedition data.Novatel FlexPak6 GPS receiver was used as navigation sensors during the campaign. Data were downloaded from DAVIS SHIP data base (https://dship.awi.de) with a resolution of 1 sec. Processed data are provided as a master track with 1 sec resolution and a generalized track with a reduced set of the most significant positions of the master track. A detailed report on processing is also available for each flight.

Description: Here, we present a record of more than 8000 km of radar survey lines of radio echo sounding data covering an area of 24 000 km2 centred on the drill site for the East Greenland Ice-core Project (EGRIP) in the central part of the North East Greenland Ice Stream (NEGIS). The acquisition system was a multichannel ultra-wideband radar mounted on AWI's Polar6 aircraft. Our data yield a new detailed model of ice-thickness distribution and basal topography in the region.

Description: This dataset contains single particle measurements performed by the PHIPS. It comprises of particle microphysical properties deduced from the stereo imaging as well as angular light scattering measurements. Please see PHIPS-HALO_Data_Readme for more details.

Description: Longwave and shortwave radiative energy budget components derived from broadband irradiance observations during the Airborne measurements of radiative and turbulent FLUXes of energy and momentum in the Arctic boundary layer (AFLUX) campaign north of Svalbard in March / April 2019. This dataset contains a subset of the entire AFLUX dataset (which will be made available later) and represents a section during the 11 April 2019 flight. This dataset contains different parameters relevant for the included estimates of cloud radiative forcing, like a cloud equivalent liquid water path equivalent derived from the shortwave transmissivity, or a cloud-free albedo estimate during cloudy observations. Details are provided in the header and doi:10.5194/acp-20-9895-2020

Description: This data set contains airborne radar data from a radio-echo sounding survey in 2018 (EGRIP-NOR) with the AWI ultra-wideband radar on Polar 6 at the onset region of the Northeast Greenland Ice Stream (NEGIS) in the vicinity of the drill site of the EGRIP ice core project (https://eastgrip.org/). The data (zip files) comprises three zip files, which represent one profile respectively: 1) UpstreamProfile_Center_IceStream 2) UpstreamProfile_Flowline_1 3) UpstreamProfile_Flowline_2 Each zip file/folder contains: (i) the radar data split into several frames and one combined file (.mat files) (ii) a folder with bedrock picks in a .csv table (iii) a folder with plots of the radar data (iv) a folder with shape-files for each radar data file (points and lines) Furthermore, a 'shapes.zip' contains one shapefile with all profiles. ============================================== AWI Flight Campaign: P6-211_EGRIP-NOR_2018 Region: Northeast Greenland, onset of Northeast Greenland Ice Stream (NEGIS) Owner/PI: Daniela Jansen (AWI), Olaf Eisen (AWI, University of Bremen) Email address of the provider: daniela.jansen@awi.de steven.franke@awi.de olaf.eisen@awi.de Instrument used: AWI UWB (MCoRDS 5) Data product: CSARP_standard (SAR processed) Method of navigation : GPS data was acquired by four NovAtel DL-V3 GPS receivers operating at 20Hz

Description: During the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign in summer 2017 conducted from Longyearbyen/Svalbard, a combination of active and passive microwave instruments MiRAC (Microwave Radar/radiometer for Arctic Clouds) has been operated on board of the Polar 5 research aircraft of the Alfred-Wegener Institute for polar and ocean research (AWI). MiRAC contains a Frequency Modulated Continuous Wave (FMCW) radar at 94 GHz mounted in a belly pod under 25deg backwards inclined with respect to nadir. Included is also the 89 GHz passive channel and a passive microwave instrument with six channels in the 183 GHz water vapor line and channels at 243 and 340 GHz installed nadir pointing in the cabin. The data set was collected during approximately 80 flight hours in May/June 2017 northwest of Svalbard over the Arctic ocean and sea ice. It contains the unfiltered reflectivity profiles as well as the filtered profiles. Both profiles are corrected for aircraft motion and instrument/aircraft orientation. The filters consider disturbances due to the signal processing, side lobe effects, and removal of speckles. Furthermore, quality flags for the radar reflectivity are included in the data set. For the passive component, the brightness temperatures at 89 GHz are included without considering the observation geometry. The data set is completed by information recorded by the aircraft system (latitude, longitude, flight height, pitch, roll, and flight speed). The data are stored as netCDF format and each file contains data for one research flight (except for the 17th and 23rd of June 2017). For the higher passive microwave channels a separate dataset will be provided. For detailed information on the instruments and the processing see Mech et al. 2019 (doi:10.5194/amt-2019-151). The campaign ACLOUD is described in Wendisch et al. 2018 (doi:10.1175/BAMS-D-18-0072.1).

Description: Analysis results of the SID-3 2D scattering patterns measured during ACLOUD. Results contain information on the particle shape, sphericity and mesoscopic complexity. Data is in NASA ames format.

Description: Vertical profiles of air temperature, humidity, pressure, and the horizontal wind vector measured by dropsondes (type RS904) released from Polar 5 during ACLOUD 2017. The profiles cover altitudes between the flight level of Polar 5 (typically 3-4 km) and the surface. Observations during ACLOUD cover a range of cloud-free and cloud covered situations over open ocean and closed sea ice west and north of Svalbard. The ASPEN software package was used to correct the raw data for the slow time response of the temperature sensor and to remove the known humidity bias. Data close to the aircraft, where the sensors still did not adjust to the outside temperature, and invalid measurements were removed by the quality check of ASPEN. To resolve temperature and humidity changes at cloud top the time response of the sensors has been corrected by an alternative method following (Miloshevich et al. 2004)

Description: Size distributions of cloud particles between 5 and 45 microns with 1 Hz time resolution calculated from the Small Ice Detector Mark 3 (SID-3). A detailed description for the data processing can be found in Vochezer et al. (2016), doi:10.5194/amt-9-159-2016. The data is in text-format with variables explained in the file header.

Description: Raw data files from all instruments operated on Polar 5 during ACLOUD 2017 (Wendisch et al. 2019). Processed data of the individual instruments are published in separate data sets and summarized in Ehrlich et al. (2019).

Description: During the ACLOUD (Arctic Cloud Observations Using airborne measurements during polar Day) campaign conducted in May/June 2017 meteorological data (temperature, 3 wind components, air pressure) have been measured in high temporal resolution (100 Hz) using instrumentation that was installed at the nosebooms of both aircraft Polar 5 and Polar 6. For each flight the data are given as functions of time and position (including height above ground) along the flight tracks. All flights started and ended in Longyearbyen, Svalbard. Each file represents an entire flight starting well before the first movement of the plane and ending after the final parking position has been reached after landing. The wind measurement is only valid during flight and the full accuracy is only achieved during straight level flight sections. The absolute accuracy of the wind components is 0.2m/s for straight and level flights sections and the relative accuracy of the vertical wind speed is about 0.05m/s for straight and level flight sections. For these sections, which can be obtained on the basis of the given roll and pitch angles of the aircraft, the 100 Hz data can be used to derive turbulent fluxes of momentum and sensible heat. For further informations on the data processing and accuracy of the turbulence measurement refer to Hartmann et al. (2018, doi:10.5194/amt-11-4567-2018). For further information on the ACLOUD campaign we refer to Wendisch et al. (2018, doi:10.1175/BAMS-D-18-0072.1). -- All data are given as decimal values at 100Hz in columns in this order and meaning: t - UTC-time in seconds (since midnight) lon - longitude in degress based on WGS84 lat - latitude in degress based on WGS84 h - height in metres based on WGS84 p - static pressure in hpa, corrected for the influence of the aircraft T - temperature from PT100, corrected for adiabatic heating u - west-east component of wind speed in m/s, positive towards east v - south-north component of wind speed in m/s, positive towards north w - vertical wind speed in m/s pitch - pitch angle in degrees roll - roll angle in degrees thdg - true heading of the aircraft in degrees

Description: During the ACLOUD (Arctic CLoud Observations Using airborne measurements during polar Day ) campaign in May / June 2017 a downward-looking commercial digital camera equipped with a 180° - fisheye lens was installed on the aircraft Polar 5. Images of the Arctic surface and clouds were taken every 6 seconds. The data set provides rectified fields of calibrated radiances along the flight track for the three spectral bands (red, green, and blue).

Description: During the ACLOUD (Arctic Cloud Observations Using airborne measurements during polar Day) campaign conducted in May/June 2017 meteorological data (temperature, horizontal wind components, air pressure) have been measured using instrumentation that was installed at the nosebooms of both aircraft Polar 5 and Polar 6. This dataset presents the 1Hz resolution data. The high temporal resolution data (at 100 Hz) with all wind components are available here: doi:10.1594/PANGAEA.900880). For each flight the data are given as functions of time and position (including height above ground) along the flight tracks. Listed in this repository are all flights beginning with the test flight in Bremen and the Ferryflights to Longyearbyen. All other measurement flights started and ended in Longyearbyen. Each file represents an entire flight starting well before the first movement of the plane and ending after the final parking position has been reached after landing. The wind measurement is only valid during flight and the full accuracy is only achieved during straight level flight sections. The absolute accuracy of the wind components is 0.2m/s for straight and level flights sections. For further informations on the data processing and accuracy of the turbulence measurement refer to Hartmann et al. (2018, doi:10.5194/amt-11-4567-2018). For further information on the ACLOUD campaign we refer to Wendisch et al. (2018, doi:10.1175/BAMS-D-18-0072.1). -- All data are given as decimal values at 1Hz in columns in this order and meaning: UTC - UTC-time in seconds (since midnight) h - height in metres based on WGS84 lon - longitude in degress based on WS84 lat - latitude in degress based on WS84 p - static pressure in hpa gs - ground speed in m/s pitch - pitch angle in degrees roll - roll angle in degrees rh - relative humidity from Vaisala at noseboom T - temperature from PT100, corrected for adiabatic heating u - west-east component of wind speed in m/s, positive towards east v - south-north component of wind speed in m/s, positive towards north tas - true air speed in m/s

Description: Solar and terrestrial broadband irradiance and nadir brightness temperature observed during the ACLOUD (Arctic CLoud Observations Using airborne measurements during polar Day) campaign in May / June 2017.

Description: Ice thickness from radar data over eastern Dronning Maud Land, with geographical coordinates and dates of acquisition in 2013, 2014, and 2015. Airborne acquisition was completed with aircraft POLAR 6 as part of the GEA collaborative project between the Federal Institute for Geosciences and Natural Resources and Alfred Wegener Institute.

Description: Airborne Laser Scanning of the Inuvik-Tuktuyaktuk-Highway (ITH) in Northwest Territories, Canada took place in August 2018 (2018-08-29). The point cloud data were acquired with a full wave-form Riegl LMSQ680i airborne laser scanner on board the Alfred-Wegener-Institute's POLAR-5 science aircraft. Basic processing and filtering steps were applied to the ALS point cloud. Based on a classification into ground and vegetation points, a Digital Terrain Model (DTM) and rasters of mean and maximum vegetation heights are derived. OPALS software was used to process the raster (tif). Detailed metadata are included.

Description: The Roi Baudouin Ice Shelf is located in an ice-shelf belt surrounding coastal Dronning Maud Land, East Antarctica. Here, we provide two radar profiles on the ice shelf, which were collected with the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research multichannel ultra-wideband (UWB) radar system in austral summer 2018/19 in a collaborative project. The radar system used the eight-element fuselage antenna array installed on AWI's Polar 6 BT-67 aircraft. Data were recorded in a frequency range of 150-520 MHz at an average altitude of 365 m above ground.

Description: The data set contains measurements performed by the passive radiometer as part of the MiRAC (Microwave Radar and radiometer for Arctic Clouds) operated on board the Polar 5 research aircraft during 14 flights of the Airborne measurements of radiative and turbulent FLUXes of energy and momentum in the Arctic boundary layer (AFLUX) campaign, carried out in spring 2019 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of brightness temperature measurements at nadir view with respect to the aircrafts fuselage at six frequencies in the water vapor absorption band at around 183.31 GHz and at two additional channels at 243 and 340 GHz. It should be considerd, that the brightness temperatures have not been corrected for aircraft attitude. The data set has been quality checked and is available in netcdf format for each flight separately. Details on the instrument can be found in Mech et al. (2019, doi:10.5194/amt-12-5019-2019).

Description: The published data set consists of measurements performed by the active cloud radar as part of the MiRAC (Microwave Radar and radiometer for Arctic Clouds) operated on board the Polar 5 research aircraft during 14 flights of the Airborne measurements of radiative and turbulent FLUXes of energy and momentum in the Arctic boundary layer (AFLUX) campaign, carried out in spring 2019 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of radar reflectivities of the FMCW 94 GHz cloud radar transformed to nadir view as well brightness temperature measurements at 89 GHz with a 25 deg backwards inclination with respect to the aircrafts fuselage. It should be considerd, that the brightness temperatures have not been corrected for aircraft attitude. The data set has been quality checked and is available in netcdf format for each flight separately. Details on the instrument can be found in Mech et al. (2019).

Description: Stable isotopes of d13C and d15N of two size fractions of microplankton were analyzed of samples taken during cruise M153 in February and March 2019 by an Apstein Net (20 µm mesh size). The sampling took place in the northern and southern Benguela upwelling system in the context of the project TRAFFIC (Trophic TRAnsfer eFFICiency in the Benguela Current). TRAFFIC aims to enlighten the energy transfer through the food webs of the northern and southern subsystems of the Benguela upwelling system. Stable isotopes help to determine the trophic level of organisms in the studied food web.

Description: Biomass of two seize fractions of microplankton was measured of samples taken during cruise M153 in February and March 2019 by a Multinet Midi (55 µm mesh size, 5 depths). The sampling took place in the northern and southern Benguela upwelling system in the context of the project TRAFFIC (Trophic TRAnsfer eFFICiency in the Benguela Current). TRAFFIC aims to enlighten the energy transfer through the food webs of the northern and southern subsystems of the Benguela upwelling system.

Description: The published data set consists of measurements performed by the active cloud radar as part of the MiRAC (Microwave Radar and radiometer for Arctic Clouds) operated on board the Polar 5 research aircraft during 10 flights of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Airborne observations in the Central Arctic (MOSAiC-ACA) campaign, carried out in late summer 2020 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of radar reflectivities of the FMCW 94 GHz cloud radar transformed to nadir view as well brightness temperature measurements at 89 GHz with a 25 deg backwards inclination with respect to the aircrafts fuselage. It should be considerd, that the brightness temperatures have not been corrected for aircraft attitude. The data set has been quality checked and is available in netcdf format for each flight separately. Details on the instrument can be found in Mech et al. (2019).

Description: The published data set consists of measurements performed by the active cloud radar as part of the MiRAC (Microwave Radar and radiometer for Arctic Clouds) operated on board the Polar 5 research aircraft during 19 flights of the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, carried out in early summer 2017 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of radar reflectivities of the FMCW 94 GHz cloud radar transformed to nadir view as well as brightness temperature measurements at 89 GHz with a 25 deg backwards inclination with respect to the aircraft fuselage The data set has been quality checked and is available in netcdf format for each flight separately. Details on the instrument can be found in Mech et al. (2019) (doi:10.5194/amt-12-5019-2019)

Description: Hyperspectral fields of visible and near infrared cloud top and surface radiance observed by AISA Eagle (1024 spatial pixels and 504 spectral channels between 400 and 993 nm) and AISA Hawk (384 spatial pixels and 288 spectral channels between 931 and 2545 nm) during the Multidisciplinary Drifting Observatory for the Study of Arctic Climate - Airborne observations in the Central Arctic (MOSAiC-ACA) campaign in September 2020.

Description: During AFLUX field campaign in spring 2019 the Basler BT-67 research aircraft Polar 5 based in Spitzbergen (78.24 N, 15.49 E) was equiped with an advanced in-situ cloud payload by the DLR including a combination of the Cloud Aerosol Spectrometer, Cloud Imaging Probe and Precipitation Imaging Probe. The data sets provides data from all DLR particle measurement instruments including micropysical cloud properties like particle size distribution, total particle number concentration, effective diameter, median volume diameter and an estimated cloud/liquid/ice water content. In combination the dataset includes all particle sizes from 2.8 - 6400.0µm in diameter. These cloud measurements were mainly conducted in low and midlevel clouds in the Fram Strait over sea ice and the open ocean. This measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)³.

Description: Longwave and shortwave cloud radiative forcing (CRF) derived from broadband irradiance observations (doi:10.1594/PANGAEA.936232) during the MOSAiC-ACA (Multidisciplinary drifting Observatory for the Study of Arctic Climate - Airborne observations in the Central Arctic) campaign in September 2020. This dataset contains only low-level flight sections. In addition, a cloud liquid water path (LWP) equivalent derived from the shortwave transmissivity is given and a cloud-free albedo estimate during cloudy observations. CRF, LWP equivalent, and the cloud-free albedo were derived using the method described by Stapf et al. (2020).

Description: Hydroacoustic raw data from the SO283 cruise aboard the RV Sonne in 2021 (19/03/2021 to 25/05/2021) from the Canary Islands to the Benguela Upwelling System. The hydroacoustics were used as underway measurements during the mooring rescue cruise in the South Atlantic. No biological reference sampling was done on this cruise. We used the Sonne's SIMRAD EK60 system with 4 frequencies: 18, 38, 120 and 200 kHz. The data was limited to 1500m depth. A trigger box was used to avoid interferences with the multibeam echosounders and ADCP during the cruise. Pinging interval is thus less consistent. Ping duration was set to 1.024ms.

Description: Hydroacoustic raw data from the M153 cruise aboard the RV Meteor in 2019 (15/02/2019 to 27/03/2019) to the Benguela Upwelling System. The hydroacoustics were used to observe the distribution of krill, zooplankton and pelagic fish up to the mesopelagic zone for the project TRAFFIC. We used a SIMRAD EK80 system with a transportable SIMRAD WBT Mini and combined transducer with 38 and 200 kHz. Data deeper than 750m has been identified as range limit and excluded.

Description: The data set contains measurements performed by the passive radiometer as part of the MiRAC (Microwave Radar and radiometer for Arctic Clouds) operated on board the Plar 5 research aircraft during 19 flights of the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, carried out in early summer 2017 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of brightness temperature measurements at nadir view with respect to the aircrafts fuselage at six frequencies in the water vapor absorption band at around 183.31 GHz and at two additional channels at 243 and 340 GHz. It should be considerd, that the brightness temperatures have not been corrected for aircraft attitude. The data set has been quality checked and is available in netcdf format for each flight separately. Details on the instrument can be found in Mech et al. (2019, doi:10.5194/amt-12-5019-2019).

Description: The published data set consists of measurements performed by the active cloud radar as part of the Microwave Radar and radiometer for Arctic Clouds (MiRAC; Mech et al., 2019) operated on board the Polar 5 research aircraft during 19 flights of the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, carried out in early summer 2017 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of radar reflectivities of the FMCW 94 GHz cloud radar transformed to nadir view as well as brightness temperature measurements at 89 GHz with a 25 deg backward inclination with respect to the aircraft's fuselage. The data set has been quality-checked and is available in NetCDF format for each flight separately.

Description: The published data set consists of measurements performed by the active cloud radar as part of the Microwave Radar and radiometer for Arctic Clouds (MiRAC; Mech et al., 2019) operated on board the Polar 5 research aircraft during 11 flights of the HALO-AC3 airborne campaign, carried out in early spring 2022 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of radar reflectivities of the FMCW 94 GHz cloud radar transformed to nadir view and brightness temperature measurements at 89 GHz with a 25 deg backward inclination with respect to the aircraft's fuselage. It should be considered that the brightness temperatures have not been corrected for aircraft attitude. The data set has been quality-checked and is available in NetCDF format for each flight separately. Details on the instrument can be found in Mech et al. (2019).

Description: Passive acoustic monitoring (PAM) data were collected by recorder SV1024 of type Sono.Vault (manufactured by develogic GmbH, Hamburg, Germany) at 78.8335° N, 6.9998° E, mooring F4-15, in Fram Strait. During a deployment period from June 2012 to June 2015, passive acoustic data were collected from June 2012 to December 2012 (recording period) by SV1024 as part of the Frontiers in Arctic Marine Monitoring (FRAM) observatory in Fram Strait. The recorder was moored at 1410 m depth and scheduled to record continuously at a sample rate of 5,333 Hz. Further details about the data acquisition and processing of this data set can be found in the accompanying metadata file (see Additional metadata) as well as the data processing report (see Data Processing Report). Passive acoustic data archived here represent data processing Level 1+, according to the standards defined in the associated Standard Operation Procedure (SOP) Glossary (Thomisch et al. 2023a). Further information on data processing with regard to data preparation and standardization can be found in the associated SOP Part 1: Data preparation and standardization (Thomisch et al. 2023b).