36 Seasonal SST Anomalies
Description: Seasonal SST Anomalies
Indicator category: Database pull with analysis
Found in: State of the Ecosystem - Gulf of Maine & Georges Bank (2018+), State of the Ecosystem - Mid-Atlantic (2018+)
Contributor(s): Sean Hardison, Vincent Saba
Data steward: Kimberly Bastille, kimberly.bastille@noaa.gov
Point of contact: Kimberly Bastille, kimberly.bastille@noaa.gov
Public availability statement: Source data are available here.
36.1 Methods
36.1.1 Data sources
Data for seasonal sea surface tempature anomalies were derived from the National Oceanographic and Atmospheric Administartion optimum interpolation sea surface temperature high resolution data set (NOAA OISST V2) provided by NOAA Earth System Research Laboratory’s Physical Science Division, Boulder, CO. The data extend from 1981 to present, and provide a 0.25° x 0.25° global grid of SST measurements (Reynolds et al. 2007).
In 2021, the Daily OISST data was updated and there are a couple papers describing and comparing the new version Huang, Liu, Banzon, et al. (2021).
36.1.2 Data extraction
Individual files containing daily mean SST data for each year during the period of 1981-present were downloaded from the OI SST V5 site. Yearly data provided as layered rasters were masked according to the extent of Northeast US Continental Shelf. Data were split into three month seasons for (Winter = Jan, Feb, Mar; Spring = Apr, May, Jun; Summer = July, August, September; Fall = Oct, Nov, Dec).
This is done in a GitHub action and is available online in ecopull.
36.1.3 Data analysis
We calculated the long-term mean (LTM) for each season-specific stack of rasters over the period of 1982-2010, and then subtracted the (LTM) from daily mean SST values to find the SST anomaly for a given year. The use of climatological reference periods is a standard procedure for the calculation of meteorological anomalies (WMO 2017). Prior to 2019 State of the Ecosystem reports, SST anomaly information made use of a 1982-2012 reference period. A 1982-2010 reference period was adopted to facilitate calculating anomalies from a standard NOAA ESRL data set.
R code used in extraction and processing gridded and timeseries data can found in the ecodata package.
catalog link https://noaa-edab.github.io/catalog/seasonal_sst_anomaly_gridded.html