The Unisys Daily Sea Surface Temperature Anomaly Maps May Be Gone


UPDATE (July 14, 2014):  Unisys is once again providing  daily sea surface temperature anomaly updates.

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Near the first of this month, the NOAA National Weather Service discontinued the sea surface temperature dataset used by Unisys to create their daily sea surface temperature and sea surface temperature anomaly maps. As a result, Unisys has been unable to update those maps. Many persons enjoyed studying the animations (see current sample to the right) because of the color coding of temperature anomalies, in which blues and greens extended into the realm of positive anomalies.

So where can you turn now for your daily fix of peaceful and calming shades of blue?


The color scalings for the temperature anomalies from the website suggested by Unisys are too harsh. It’s from the NOAA National Weather Service Environmental Modeling Center  webpage Real-time, global, sea surface temperature (RTG_SST_HR) analysis. See Map 1. A description of that analysis is here.

Map 1NWS color_newdisp_anomaly_global_lat_lon_ophi0

Map 1

The maps from the Environmental Modeling Center have three strikes against them:

  • Strike 1: I haven’t found animations of those maps. They may exist, but with the other two strikes, I didn’t see any reason to spend too much time looking.
  • Strike 2: While they use white as their neutral color, they only use it for the range of +/- 0.25 deg C. That’s way too narrow, giving too much visual “noise”.
  • Strike 3: They use 1961 to 1990 as the base years for anomalies. That’s two decades behind the period (1981 to 2010) recommended by the World Meteorological Organization (WMO). The NOAA Climate Prediction Center updated the climatologies they use for many indices three years ago to 1981 to 2010. The NOAA Environmental Modeling Center should update theirs.


There are a number of other suppliers of daily sea surface temperature and anomaly maps, but the one I’ve recently bookmarked as a temporary replacement for those from Unisys come from Environment Canada (EC).   See their Sea Surface Temperature Anomalies and Snow Cover – Daily webpage.  A recent example is shown in Map 2.  Greys are also used on the maps for snow cover and sea ice.  Cool.

Map 2 2014062100_054_G6_global_I_SEASON_tm@lg@sd_000

Map 2

Brrr.  The Main Development Region for hurricanes in the tropical North Atlantic (10N-20N, 80W-20W) looks awfully chilly.  Unfortunately, hurricanes don’t care about anomalies.  Hurricanes only need the seasonal sea surface temperatures to rise to the levels that support their development and sustain them.  Hopefully, the present El Niño conditions in the tropical Pacific will suppress them in the North Atlantic.

  • Advantage 1: Animations are available from the Environment Canada webpage here. Users can also select the time period for the animation. The menus are below the map.
  • Advantage 2: The range they use for neutral white is +/- 0.5 deg C. That reduces weather noise.
  • Advantage 3: The base years used by Environment Canada (1995 to 2009) are closer to present. Unfortunately, they’re only 15 years. I suspect the base years are based either on the snow cover or sea ice data, because satellite-based sea surface temperature data extend back to November 1981.
  • Advantage 4: You can watch the seasonal variations in sea ice and snow cover, too.

If you know of others, please let me know.



About Bob Tisdale

Research interest: the long-term aftereffects of El Niño and La Nina events on global sea surface temperature and ocean heat content. Author of the ebook Who Turned on the Heat? and regular contributor at WattsUpWithThat.
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7 Responses to The Unisys Daily Sea Surface Temperature Anomaly Maps May Be Gone

  1. Pamela Gray says:

    The psychology of color is an important are of consideration in advertising. Two different colors having the same numerical shade (equal darkness value – 100% saturated pure color with the exact same amount of black added) can appear to humans as lighter or darker than the other. When I see a color scheme used to show data I always scrutinize the key to see if the authors are fiddling with color to gain some kind of psychological message advantage. That appears to be the case in the NOAA maps. If you directly compare the color keys of the two alternative maps this message is quite clear. You wouldn’t even have to see an actual map to discuss what the color keys are trying to say.

    You would think that a typical map would at least have the same shade of cold blue and hot red that were equidistant from 0. But even then, the human eye may perceive one as darker than the other, thus skewing the perception of anomaly, which may be something you want to do, or something you want to avoid doing. For example, look at the shade of +2F and -2F between the two color keys. Clearly the two different map sources are purposely playing with equidistant shade and color in some way. Maybe one is trying to send a message that is pointedly psychological in order to say something more than the map can say in words (and get away with it), whereas the other wants to avoid the psychological meanings of color shade and choice in order to convey a more straightforward message.

    One thing for sure, subtle they are not. What a difference!

  2. Thanks, the Sea Surface Temperature Anomalies and Snow Cover graphic from Environment Canada is very good. I could never use the Unisys graphs because of their coloring scheme.

  3. try SSTA maps from STORMVISTA.COM

  4. Anton says:

    Do you know the base period in Unysis new map ? Thanks, Bob

  5. Bob Tisdale says:

    Sorry, Anton. I have no idea what the base years are of the NOAA analysis used by Unisys.


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