DOI: 10.3886/e233223
title: Climate.gov Data Snapshots: Ocean Heat Content - Seasonal Difference from Average

description: <b>Q: How much heat energy is being stored in Earth’s ocean?
</b><b>
 </b><br><b>A:</b> Colors
 on the map show where instruments detected more or less heat energy in 
the top 2,300 feet of water than the long-term average annual heat 
content. Orange areas show where heat content was higher than the 
long-term average. Blue areas show where heat content was lower than the
 long-term average. The darker the shade of blue or orange, the larger 
the heat-content difference from the long-term average.

 
 <br><b>Q: Where do these measurements come from?
</b><b>
 </b><br><b>A:</b> Oceanographers
 use a range of temperature-sensing instruments to measure heat energy 
in the ocean. Among them is a fleet of more than 3,000 robotic “floats” 
that measure ocean temperature in the top 2,300 feet of water. 
Scientists constantly compare data from floats, probes, and 
Conductivity-Temperature-Depth (CTD) sensors to verify that the values 
they produce make sense.

 
 <br><b>Q: What do the colors mean?</b><b>
 </b><br><b>A:</b> Colors
 show the relative differences in average heat energy in the top 2,300 
feet of the ocean, computed for each year, compared to long-term average
 annual heat content. The long-term temperature climatology is the 
average of five “decadal” climatologies calculated for 1955-1964, 
1965-1974, 1975-1984, 1985-1994, and 1995-2006. Orange and blue areas 
show where the upper ocean’s heat storage rose or fell by up to 3 
gigajoules (109 joules) per square meter at the surface. Areas where heat content was close to the long-term average are white.

 
 <br><b>Q: Why do these data matter?</b><b>
 </b><br><b>A:</b> The
 ocean’s ability to store and release heat over long periods of time 
gives it a central role in stabilizing Earth’s climate system. 
Short-term variations in heat content due to natural climate patterns 
like El Niño influence regional climates, tropical cyclones, and marine 
life, including coral reefs and fisheries. As the ocean takes up more 
heat due to global warming, water temperatures rise, causing it to 
increase in volume, raising global sea level around the world. Warming 
ocean waters also have major implications for marine ecosystems, melting
 ice caps, and precipitation patterns.

 
 <br><b>Q: How did you produce these snapshots?</b><b>
 </b><br><b>A:</b> Data
 Snapshots are derivatives of existing data products. To meet the needs 
of a broad audience, we present the same data as current products in a 
simplified visual style. This set of snapshots is based on data from 
NOAA’s Ocean Climate Laboratory.

To produce the maps for Data Snapshots, we run a script that accesses
 the source data, applies a custom color palette, and assembles them on a
 prepared base map.

 
 
 
 <br><b>References</b>
 
 Levitus, S., et al. (2012), World ocean heat 
content and thermosteric sea level change (0–2000 m), 1955–2010, 
Geophys. Res. Lett., 39, L10603.
 <br>Source: https://www.climate.gov/maps-data/data-snapshots/data-source/ocean-heat-content-seasonal-difference-average<br><br>This upload includes two additional files:<br>* Ocean Heat Content - Seasonal Difference from Averge _NOAA Climate.gov.pdf is a screenshot of the main Climate.gov site for these snapshots (https://www.climate.gov/maps-data/data-snapshots/data-source/ocean-heat-content-seasonal-difference-average)<br>* Cimate_gov_ Data Snapshots.pdf is a screenshot of the data download page for the full-resolution files.<br><br><br>
description: Data is divided in to folders by image resolution -- full size (zip), kml (zip), broadcast (png), small (png), and large (png). Occasionally there may be one image missing in a particular size but available in another size.<br><br>Data downloaded from climate.gov 6/15/2025 - 6/16/2025 (small, large, and full resolution) and 6/21/2025 (others).