Open Access Data in Polar and Cryospheric Remote Sensing

Abstract

This paper aims to introduce the main types and sources of remotely sensed data that are freely available and have cryospheric applications. We describe aerial and satellite photography, satellite-borne visible, near-infrared and thermal infrared sensors, synthetic aperture radar, passive microwave imagers and active microwave scatterometers. We consider the availability and practical utility of archival data, dating back in some cases to the 1920s for aerial photography and the 1960s for satellite imagery, the data that are being collected today and the prospects for future data collection; in all cases, with a focus on data that are openly accessible. Derived data products are increasingly available, and we give examples of such products of particular value in polar and cryospheric research. We also discuss the availability and applicability of free and, where possible, open-source software tools for reading and processing remotely sensed data. The paper concludes with a discussion of open data access within polar and cryospheric sciences, considering trends in data discoverability, access, sharing and use.

The Greater Caucasus Glacier Inventory (Russia, Georgia and Azerbaijan)

“…Direct field monitoring reveals evident debris expansion for some glaciers (e.g. Djankuat) from 2 to 13 % between 1968 and 2010 (Popovnin et al, 2015). Glacier retreat appears to be associated with expansion of supra-glacial debris cover and ice-contact/proglacial lakes, which may increase the likelihood of glacier-related hazards and debris flows (Stokes et al, 2007).…”

“…We utilize increasingly accessible global satellite imagery (Wulder et al, 2012(Wulder et al, , 2016Pope et al, 2014) to investigate glacier area and number change in the Greater Caucasus in the periods 1960-1986, 1986-2014 and 1960-2014. Changes in glacier extent in the Greater Caucasus between 1986 and 2014 were determined through analysis of images from the Landsat 5 Thematic Mapper (TM), Landsat 8 Operational Land Imager (OLI) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) ( Table 1).…”

Single-footprint retrievals of temperature, water vapor and cloud properties from AIRS

“…An observation-based a priori covariance (including cross-species covariances), specific to region and season, would provide improved constraints and more realistic retrieval errors. A method of 20 assigning ground-level snow and ice conditions to observations is needed -possibly from the co-located AMSU microwave instrument or other near-real-time data (see Pope et al, 2014). Addition of effective emissivity retrievals will likely be necessary to improve results over "difficult" regions, such as deserts or mountains, and could include some weighting by, say, the MODIS cloud mask to determine an a priori emissivity as it affects the AIRS observation by taking cloud cover into account.…”

Single-footprint retrievals of temperature, water vapor and cloud properties from AIRS

“…5.1 of Rodgers (2000), would help to flag those retrievals where the error estimation may be suspect. A method of assigning ground-level snow and ice conditions to observations is needed -possibly from the colocated AMSU microwave instrument or other near-real-time data (see Pope et al, 2014). Addition of effective emissivity retrievals will likely be necessary to improve results over difficult regions, such as deserts or mountains.…”