isotherms-contourplots

Create isotherms for 163 (1854 - 2017) years of Monthly Mean of Sea Surface Temperature Calculate mean latitude of 13oC isotherm

Data source: https://www.esrl.noaa.gov/psd/cgi-bin/DataAccess.pl?DB_dataset=NOAA+Extended+Reconstructed+SST+V4&DB_variable=Sea+Surface+Temperature&DB_statistic=Mean&DB_tid=60700&DB_did=168&DB_vid=4133

Coordinates: 48.5N-52.5N, 12.5W-4.5W

Area: Celtic Sea