list("Snow is a crucial resource for billions of people on Earth. We proposed a study of snow drifts. Drifts can comprise more than half of the local snow water equivalent (SWE) and play a large and widely overlooked role in snow hydrology. They melt slowly, resulting in a crucial shift in the timing of water delivery that syncs snow melt directly to agricultural and ecosystem needs, yet we know little about drifts on either local or global scales. The overall goal of the research was to better understand the role and importance of snow drifts in hydrology. Using lidar and structure-from-motion (SfM) photogrammetry, we conducted an airborne study of drifts coupled with extensive ground validation in search of preliminary answers to questions on the importance of drifts and the percentage of SWE found in drifts in a variety of terrain types.", "The snow depth maps hosted here represent six years of drift records from northern Alaska and enable the analysis of the relationships between drifts and the surrounding snowcover and the landscape below, as well as drift persistence over time.", "Snow depth mapping was done using airborne SfM photogrammetry (2015 through 2018) and lidar (2012 and 2013) and then adjusted to ground-based probe measurements of snow depth. The area mapped each year over two swaths was about 130 kilometer squared (km^2). To produce the maps, we: (1) conducted an airborne survey (snow-free) in June that was used to produce a snow-free digital elevation model (DEM) for each swath, (2) conducted airborne surveys at near-peak snow cover each April that were used to create digital surface models (DSMs) of the snow cover, then (3) generated annual high resolution (1 m) snow depth maps by subtracting the snow-free DEM from the DSMs. Six such depth maps were produced for each swath between 2012 and 2018, comprising over 600 million individual geospatial snow depth records. Acquiring the snow-free DEM required careful timing because tundra plants leaf out before all snowdrifts melt. The snow depth maps were field-validated and adjusted using 141,207 ground-based probe measurements collected concurrently with the airborne surveys.", "There are twelve (12) snow depth raster maps deposited here. Each map represents the near-peak annual snow depth across a swath of Arctic tundra. There are two swaths: CLPX (a zone that was part of a Cold Land Experimental Site - a NASA snow measurement program that rotates through several different field areas) and HV (Happy Valley). Map years include 2012, 2013, 2015, 2016, 2017, and 2018. Maps are raster data GeoTIFF file formats where each pixel is one by one meter square. The file naming convention is swathdepthDOY_*YYYY*_corrected_*correction_amount*.tif.")

The PlanetScope Level 1B Basic Scene and Level 3B Ortho Scene full archive products are available as part of Planet imagery offer. The Unrectified Asset: PlanetScope Basic Analytic Radiance (TOAR) product is a Scaled Top of Atmosphere Radiance (at sensor) and sensor corrected product, without correction for any geometric distortions inherent in the imaging processes and is not mapped to a cartographic projection. The imagery data is accompanied by Rational Polynomial Coefficients (RPCs) to enable orthorectification by the user. This kind of product is designed for users with advanced image processing and geometric correction capabilities. Basic Scene Product Components and Format Product Components Image File (GeoTIFF format) Metadata File (XML format) Rational Polynomial Coefficients (XML format) Thumbnail File (GeoTIFF format) Unusable Data Mask UDM File (GeoTIFF format) Usable Data Mask UDM2 File (GeoTIFF format) Bands 4-band multispectral image (blue, green, red, near-infrared) or 8-band (coastal-blue, blue, green I, green, yellow, red, Rededge, near-infrared) Ground Sampling Distance Approximate, satellite altitude dependent Dove-C: 3.0 m-4.1 m Dove-R: 3.0 m-4.1 m SuperDove: 3.7 m-4.2 m Accuracy <10 m RMSE The Rectified assets: The PlanetScope Ortho Scene product is radiometrically-, sensor- and geometrically- corrected and is projected to a UTM/WGS84 cartographic map projection. The geometric correction uses fine Digital Elevation Models (DEMs) with a post spacing of between 30 and 90 metres. Ortho Scene Product Components and Format Product Components Image File (GeoTIFF format) Metadata File (XML format) Thumbnail File (GeoTIFF format) Unusable Data Mask UDM File (GeoTIFF format) Usable Data Mask UDM2 File (GeoTIFF format) Bands 3-band natural colour (red, green, blue) or 4-band multispectral image (blue, green, red, near-infrared) or 8-band (coastal-blue, blue, green I, green, yellow, red, RedEdge, near-infrared) Ground Sampling Distance Approximate, satellite altitude dependent Dove-C: 3.0 m-4.1 m Dove-R: 3.0 m-4.1 m SuperDove: 3.7 m-4.2 m Projection UTM WGS84 Accuracy <10 m RMSE PlanetScope Ortho Scene product is available in the following: PlanetScope Visual Ortho Scene product is orthorectified and colour-corrected (using a colour curve) 3-band RGB Imagery. This correction attempts to optimise colours as seen by the human eye providing images as they would look if viewed from the perspective of the satellite. PlanetScope Surface Reflectance product is orthorectified, 4-band BGRN or 8-band Coastal Blue, Blue, Green I, Green, Yellow, Red, RedEdge, NIR Imagery with geometric, radiometric and corrected for surface reflection. This data is optimal for value-added image processing such as land cover classifications. PlanetScope Analytic Ortho Scene Surface Reflectance product is orthorectified, 4-band BGRN or 8-band Coastal Blue, Blue, Green I, Green, Yellow, Red, RedEdge, NIR Imagery with geometric, radiometric and calibrated to top of atmosphere radiance. As per ESA policy, very high-resolution imagery of conflict areas cannot be provided.