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As part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), the HELiX uncrewed aircraft system (UAS) was deployed over the sea ice in the central Arctic Ocean during summer 2020. Albedo measurements were obtained with stabilized pyranometers, and melt pond fraction was calculated from orthomosaic imagery from a surface-imaging multispectral camera. This study analyzed HELiX flight data to provide insights on the temporal and spatial evolution of albedo and melt pond fraction of the MOSAiC floe during the melt season as it drifted south through Fram Strait. The surface albedo distributions showed peak values changing from high albedo (0.55–0.6) to lower values (0.3) as the season advanced. Inspired by methods developed for satellite data, an algorithm was established to retrieve melt pond fraction from the orthomosaic images. We demonstrate that the near-surface observations of melt pond fraction were highly dependent on sample area, offering insight into the influence of subgrid scale features and spatial heterogeneity in satellite observations. Vertical observations conducted with the HELiX were used to quantify the influence of melt pond scales on observed surface albedo as a function of sensor footprint. These scaling results were used to link surface-based measurements collected during MOSAiC to broader-scale satellite data to investigate the influence of surface features on observed albedo. Albedo values blend underlying features within the sensor footprint, as determined by the melt pond size and concentration. This study framed the downscaling (upscaling) problem related to the airborne (surface) observations of surface albedo across a variety of spatial scales. 

Abstract. This study analyzes turbulent energy fluxes in the Arctic atmospheric boundary layer (ABL) using measurements with a small uncrewed aircraft system (sUAS). Turbulent fluxes constitute a major part of the atmospheric energy budget and influence the surface heat balance by distributing energy vertically in the atmosphere. However, only few in situ measurements of the vertical profile of turbulent fluxes in the Arctic ABL exist. The study presents a method to derive turbulent heat fluxes from DataHawk2 sUAS turbulence measurements, based on the flux gradient method with a parameterization of the turbulent exchange coefficient. This parameterization is derived from high-resolution horizontal wind speed measurements in combination with formulations for the turbulent Prandtl number and anisotropy depending on stability. Measurements were taken during the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition in the Arctic sea ice during the melt season of 2020. For three example cases from this campaign, vertical profiles of turbulence parameters and turbulent heat fluxes are presented and compared to balloon-borne, radar, and near-surface measurements. The combination of all measurements draws a consistent picture of ABL conditions and demonstrates the unique potential of the presented method for studying turbulent exchange processes in the vertical ABL profile with sUAS measurements. 

Abstract. The DataHawk2 (DH2) is a small, fixed-wing, uncrewed aircraft system, or UAS,developed at the University of Colorado (CU) primarily for taking detailedthermodynamic measurements of the atmospheric boundary layer. The DH2 weighs1.7 kg and has a wingspan of 1.3 m, with a flight endurance of approximately60 min, depending on configuration. In the DH2's most modern form, theaircraft carries a Vaisala RSS-421 sensor for pressure, temperature, andrelative humidity measurements, two CU-developed infrared temperaturesensors, and a CU-developed fine-wire array, in addition to sensors requiredto support autopilot function (pitot tube with pressure sensor, GPSreceiver, inertial measurement unit), from which wind speed and directioncan also be estimated. This paper presents a description of the DH2,including information on its design and development work, and puts the DH2 intocontext with respect to other contemporary UASs. Data from recent field work(MOSAiC, the Multidisciplinary drifting Observatory for the Study of ArcticClimate) is presented and compared with radiosondes deployed during thatcampaign to provide an overview of sensor and system performance. These datashow good agreement across pressure, temperature, and relative humidity aswell as across wind speed and direction. Additional examples of measurementsprovided by the DH2 are given from a variety of previous campaigns inlocations ranging from the continental United States to Japan and northernAlaska. Finally, a look toward future system improvements and upcomingresearch campaign participation is given. 

A0 level data from HELiX Uncrewed Aircraft System correspond to the raw data in Matlab format collected in the Central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Synchronized and quality-controlled B1 level data are available in the Arctic Data Center. Users are encouraged to primarily use the B1 level data for analysis (doi:10.18739/A2GH9BB0Q). Raw data are the initial inputs in the processing routines to obtain the B1 and A1 level data (doi:10.18739/A2M90243X). Matlab files include hemispheric irradiance measurements from Kipp and Zonen pyranometers and thermodynamic parameters from Vaisala RSS421 sensors. Autopilot positions and attitudes, along with gimbal attitudes are also provided. Each field of measurements has its own time stamped based on a common clock and associated acquisition frequency. As no Coordinated Universal Time (UTC) time was provided in the FlexLogger acquisition files, the additional A0_PixHawk Matlab files obtained directly from the PixHawk autopilot are used to add UTC time for B1 level data. Please contact the authors if you need to use this dataset. More information on the data and method can be found in de Boer, G. R. Calmer, G. Jozef, J. Cassano, J. Hamilton, D. Lawrence, S. Borenstein, A. Doddi, C. Cox, J. Schmale, A. Preußer and B. Argrow (2022): Observing the Central Arctic Atmosphere and Surface with University of Colorado Uncrewed Aircraft Systems, Nature Scientific Data, in prep. 

Over a five-month time window between March and July 2020, scientists deployed two small uncrewed aircraft systems (sUAS) to the central Arctic Ocean as part of legs three and four of the MOSAiC expedition. These sUAS were flown to measure the thermodynamic and kinematic state of the lower atmosphere, including collecting information on temperature, pressure, humidity and winds between the surface and 1 km, as well as to document ice properties, including albedo, melt pond fraction, and open water amounts. The atmospheric state flights were primarily conducted by the DataHawk2 sUAS, which was operated primarily in a profiling manner, while the surface property flights were conducted using the HELiX sUAS, which flew grid patterns, profiles, and hover flights. In total, over 120 flights were conducted and over 48 flight hours of data were collected, sampling conditions that included temperatures as low as −35 °C and as warm as 15 °C, spanning the summer melt season.

 

This dataset includes unprocessed raw data from DataHawk2 fixed-wind uncrewed aircraft system (UAS) flights that were conducted in the central Arctic Ocean over sea ice during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Synchronized and quality controlled data are available in the Arctic Data Center at doi:10.18739/A22Z12Q8X for data provided at their native frequency logged on board the aircraft’s secure digital (SD) card (A1 level files), or at doi:10.18739/A2Z60C34R for data interpolated to a common 10 hertz (Hz) clock (B1 level files). Users are encouraged to primarily use the B1 level data for analysis. Please contact the authors if you plan to use this dataset. More information on data collection with the DataHawk2 can be found in de Boer, G. R. Calmer, G. Jozef, J. Cassano, J. Hamilton, D. Lawrence, S. Borenstein, A. Doddi, C. Cox, J. Schmale, A. Preußer and B. Argrow (2022): Observing the Central Arctic Atmosphere and Surface with University of Colorado Uncrewed Aircraft Systems, Nature Scientific Data, submitted. 

Abstract. The mesoscale meteorology of lake breezes along Lake Michiganimpacts local observations of high-ozone events. Previous manned aircraftand UAS observations have demonstrated non-uniform ozone concentrationswithin and above the marine layer over water and within shorelineenvironments. During the 2021 Wisconsin's Dynamic Influence of ShorelineCirculations on Ozone (WiscoDISCO-21) campaign, two UAS platforms, afixed-wing (University of Colorado RAAVEN) and a multirotor (PurdueUniversity DJI M210), were used simultaneously to capture lake breeze duringforecasted high-ozone events at Chiwaukee Prairie State Natural Area insoutheastern Wisconsin from 21–26 May 2021​​​​​​​. The RAAVEN platform (data DOI:https://doi.org/10.5281/zenodo.5142491, de Boer et al., 2021) measured temperature, humidity, and 3-D winds during2 h flights following two separate flight patterns up to three times per dayat altitudes reaching 500 m above ground level (a.g.l.). The M210 platform (data DOI: https://doi.org/10.5281/zenodo.5160346, Cleary et al., 2021a) measured vertical profiles of temperature, humidity,and ozone during 15 min flights up to six times per day at altitudesreaching 120 ma.g.l. near a Wisconsin DNR ground monitoringstation (AIRS ID: 55-059-0019). This campaign was conducted in conjunctionwith the Enhanced Ozone Monitoring plan from the Wisconsin DNR that included Dopplerlidar wind profiler observations at the site (dataDOI: https://doi.org/10.5281/zenodo.5213039, Cleary et al., 2021b). 

Data are available for download at: https://arcticdata.io/data/10.18739/A2RV0D21Z/ This dataset consists of multispectral imagery data products produced from HELiX uncrewed aircraft system (UAS) flights that were conducted over or near sea ice during the MOSAiC expedition. These data were produced from raw multispectral imagery acquired by the Helix’s gimbal-mounted RedEdge-MX camera. Additional data from the Helix UAS’ other sensors, which consist of hemispheric irradiance measurements from two Kipp and Zonen pyranometers and thermodynamic parameters from two Vaisala RSS421 sensors can be found in Radiance Calmer, Gijs de Boer, Jonathan Hamilton, Dale Lawrence, Steve Borenstein, et al. 2021. HELiX Uncrewed Aircraft System data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate campaign, A1 level data. Arctic Data Center. doi:10.18739/A2M90243X (A1 data) or Radiance Calmer, Gijs de Boer, Jonathan Hamilton, Dale Lawrence, Steve Borenstein, et al. 2021. HELiX Uncrewed Aircraft System data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Campaign. Arctic Data Center. doi:10.18739/A2GH9BB0Q (B1 data). Three main flight types were conducted with the Helix: a grid pattern, hover, and profile. Pix4D was used to produce five (one for each channel of the camera) orthomosaics, reflectance maps, and colorized index maps for all flight types. A video of the images taken during the flight, including an image scale, UTC time, and altitude overlay was produced for each profile flight. More information on the data and methods can be found in de Boer, G. R. Calmer, G. Jozef, J. Cassano, J. Hamilton, D. Lawrence, S. Borenstein, A. Doddi, C. Cox, J. Schmale, A. Preußer and B. Argrow (2021): Observing the Central Arctic Atmosphere and Surface with University of Colorado Uncrewed Aircraft Systems, Nature Scientific Data, in prep. 

The dataset is derived from HELiX Uncrewed Aircraft System flights that were conducted in the Central Arctic Ocean over sea ice during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The data include Universal Coordinated Time (UTC), downwelling and upwelling shortwave radiation measurements, and position and attitude from the Uncrewed Aircraft System (UAS). Temperature, relative humidity and pressure from two different sensors are also provided. A quality control flag is associated with each scientific measurement. A flight flag is also included to indicate the different phases of the flight - on the ground, take-off/landing phases, and in flight. All the data have been synchronized and interpolated at 10 hertz (Hz). The purpose of this dataset is to provide information on albedo over different features of the sea ice (snow, melt pond, ocean). Three flight patterns were implemented during the campaign with the HELiX, a grid pattern at constant altitude (15 meters or 7 meters above ground level), hovering flights ( 2-5 minutes hovering over identified sea ice features at low altitude ~ 3 meters above ground level), and profiles up to 400 meters above ground level. Displaying latitude, longitude and altitude will help users to identify the flight pattern. Albedo measurements have been validated with surface-based measurements and details can be found in de Boer, G. R. Calmer, G. Jozef, J. Cassano, J. Hamilton, D. Lawrence, S. Borenstein, A. Doddi, C. Cox, J. Schmale, A. Preußer and B. Argrow (2021): Observing the Central Arctic Atmosphere and Surface with University of Colorado Uncrewed Aircraft Systems, Nature Scientific Data, in prep. 

A1 level data from HELiX Uncrewed Aircraft System correspond to the raw data collected in the Central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Synchronized and quality-controlled B1 level data are also available in the Arctic Data Center. Users are encouraged to primarily use the B1 level data for analysis. A1 level data include hemispheric irradiance measurements from Kipp and Zonen pyranometers and thermodynamic parameters from Vaisala RSS421 sensors. Autopilot positions and attitudes, along with gimbal attitudes are also provided. Each field of measurements has its own time stamped based on a common clock and associated acquisition frequency. No synchronization or Universal Coordinated Time (UTC) are provided at the A1 level. This dataset is used to create the B1 level data at 10 hertz (Hz) with quality-controlled flags. More information on the data and method can be found in de Boer, G. R. Calmer, G. Jozef, J. Cassano, J. Hamilton, D. Lawrence, S. Borenstein, A. Doddi, C. Cox, J. Schmale, A. Preußer and B. Argrow (2021): Observing the Central Arctic Atmosphere and Surface with University of Colorado Uncrewed Aircraft Systems, Nature Scientific Data, in prep.