------------------------------------------------------------------ Utqiagvik (formerly Barrow), Alaska Microtopographic Historical Site Reflectance data Alaska, USA, 2018 Data authors: Sergio Vargas Zesati (1), Craig E. Tweedie (1), Karl F. Huemmrich (2), Petya Campbell (2) 1. Systems Ecology Lab, University of Texas at El Paso 2. University of Maryland Baltimore County, NASA Goddard Space Flight Center Funding from: NASA ABoVE (Grant # NNX17AC58A) Version: 2018-07-25 -------------------------------------------------------------------- CONTENTS 1. Data overview 2. Use of data 3. Temporal and spatial characteristics 4. File information -------------------------------------------------------------------- 1. DATA OVERVIEW This dataset represents full-spectrum (i.e. 350-2500nm) plot-level spectral reflectance data for plots within the Microtopo site near Utqiagvik, Alaska. Scans were collected using a Spectra Vista Corporation (SVC) HR-1024i spectrometer, standard pistol grip and fibers. Data were calibrated using a Spectralon white reference panel for changing light conditions during field sampling. ***Warning*** Some dates might be missing scans due to either bad data and/or as a result of data QC efforts. Data Uncertainty: No specific quality assessment information is provided. Correspondence concerning these data should be directed to: Dr. Sergio A. Vargas Zesati University of Texas at El Paso Systems Ecology Lab 500 W. University Ave. El Paso, Texas, 79968 email: savargas@utep.edu ctweedie@utep.edu -------------------------------------------------------------------- 2. USE OF DATA These data are made freely available to the public and the scientific community in the belief that their wide dissemination will lead to greater understanding and new scientific insights. -------------------------------------------------------------------- 3. TEMPORAL AND SPATIAL CHARACTERISTICS Temporal range: 2017-06-17 to 2017-08-22 Temporal resolution / sampling frequency: 1 time during the peak field season Geographic location / Transect boundaries: Westernmost Longitude: -156.683913° Easternmost Longitude: -156.683485° Northernmost Latitude: 71.290020° Southernmost Latitude: 71.289746° Site description: In 1973, a microtopographic grid was established during the International Biological Programme (IBP) near Utqia?vik, Alaska to document the interaction between microtopography, periglacial processes and vegetation patterns. The grid is oriented over several low centered polygons, is 34 meters long by one meter wide and marked by wooden stakes placed at half-meter intervals in a grid design. It was re-sampled in 2000 - 2002, 2008, and 2017 - 2018. This grid remained intact until 2000; damaged pegs were found during the 2008 and 2017 resampling years possibly due to ATV/snowmobile traffic. Changes in land cover have been assessed using a Geographic Information System (GIS) and modern spatial analysis and modeling techniques. Visible changes in surface topography, active layer depth, and vegetation have occurred over the past 45 years since this grid was established. This study reinforces the research potential of revisiting historical research sites to help answer modern scientific dilemmas of global climate change This study was directed by Drs. Craig E. Tweedie and Patrick J. Webber during the 2000 field season with Dr. Tweedie taking over for the 2008, 2017 and 2018 field seasons. Callaghan, T. V, Tweedie, C. E., Åkerman, J., Andrews, C., Bergstedt, J., Butler, M. G., … Ls, /. (n.d.). Multi-Decadal Changes in Tundra Environments and Ecosystems: Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF). Source: AMBIO: A Journal of the Human Environment, 40(6), 705–716. https://doi.org/10.1007/s13280-011-0179-8 Villarreal, S., Hollister, R. D., Johnson, D. R., Lara, M. J., Webber, P. J., & Tweedie, C. E. (2012). Tundra vegetation change near Barrow, Alaska (1972–2010). Environmental Research Letters. https://doi.org/10.1088/1748-9326/7/1/015508 Webber, P. J. (1978). Spatial and temporal variation of the vegetation and its production, Barrow, Alaska. In Vegetation and production ecology of an Alaskan arctic tundra (L.L. Tieszen, Ed.). New York: Springer-Verlag. Chap 3. Spatial resolution: average spectral reflectance for an approximate 1 meter squared area. -------------------------------------------------------------------- 4. FILE INFORMATION Data file format: comma-separated text (.csv) Data file description: The first row in each csv data file represents the wavelength (nm) and each row following thereafter is each plot or scan and are identified using the Unique_ID in column A, which is linkable with the metadata spreadsheet information (see below). The coordinates provided in the metadata spreadsheet were acquired using either a DGPS or handheld GPS. Metadata file description: Each scan or data record is stored by row and is assigned a Unique_ID, which can be used to query a particular measurement as detailed as by day and/or time of day. As seen in the metadata sheet, the Unique_ID column is basically composed of the first 8 columns of metadata which include the “Location”, “Site_Name”, “Target_Name”, “Target_Scale_Level” (e.g. plot (PL), leaf (LF) etc.), “Measurement_Julian_Day”, “Measurement_Time_Of_Day”, “Measurement_Year”, and “Measurement_Type” (e.g. reflectance (REFL), radiance (RAD) etc.). --------------------------------------------------------------------