Mean and standard deviation of sea ice concentration values within 200km of the seven emperor penguin colonies in the Ross Sea, and the overall Ross Sea region (165E-150W, 65S-79S) Eight Regions of Interest (ROIs) created in ArcGIS Pro. Using latitude and longitude points for each penguin colony and creating a 200km buffer around each point and excluding the area covered by continent. Ross Sea ROI was created using ‘Go to XY’ function, placing markers at 165E-150W, 65S-79S, drawing a polygon between the points, then excluding areas covered by continent.
#Sea ice concentration geotiff data were gathered through NSIDC (https://masie_web.apps.nsidc.org/pub/DATASETS/NOAA/G02135/south/monthly/geotiff/) Images are 25 km data cell color-coded in shades of blue to white, where dark blue is zero percent ice (open ocean) and white is 100 percent ice. We wanted to extract the mean sea ice coverage within each of our ROIs, and calculate the ‘seasonal’ (or three-monthly) averages and standard deviations. This was done in R. Our seasons are Jan-Feb-Mar (JFM), Apr-May-Jun (AMJ), Jul-Aug-Sep (JAS), & Oct-Nov-Dec (OND). These were chosen as each three month period relates to a different aspect of the emperor penguin lifecycle.
#We extracted the monthly sea ice concentration data using the ROIs in R, before creating a variable with dates month, year and season. We were then able to take the mean and sd of the seasons for each year from 2000-2021