METR 104:
Our Dynamic Weather
(Lecture w/Lab)
Some Mostly
Common-Sense Properties
of Features that You Can See
on GOES Weather-Satellite Images
Dr. Dave Dempsey
Dept. of Geosciences
SFSU, Fall 2012

Using some common sense, plus information provided in class and in the handout "Weather Satellite Images", you should be able to answer the questions below. [Note: answers are provided.]

(1) What four broad categories of features are generally visible on GOES weather-satellite images?

(2) Below, categorize the four features above according to their typical relative albedo and temperatures. (In some cases you will want to consider time of year, time of day, altitude, elevation, or latitude. For example, high-altitude land surfaces are generally relatively cold compared to low-altitude land, all else being equal.)

Features Typically with a
Relatively High Albedo
Features Typically with a
Relatively Low Albedo
  • Cloud tops
  • Snow/ice surfaces
  • Land surfaces (though vegetated areas generally have significantly lower albedo than unvegetated areas, such as deserts, do)
  • Ocean surfaces (which generally have the lowest albedo of all; when the angle between the ocean surface and the sun is just right, the ocean will reflect most of the light striking it, but that's the exception rather than the rule)

Features Typically
with a
High Temperature
  Features Typically
with a
Low Temperature
  Snow/ice surfaces
Land surfaces
at low elevations
<---> Land surface
at high elevations
Land and ocean surfaces
at low latitudes
<---> Land and ocean surfaces
at high latitudes
Land surfaces
in early/mid afternoon
<---> Land surfaces
near sunrise
[Land surfaces
in mid/late summer
<---> Land surfaces
in mid/late winter]*
[Ocean surfaces
in late summer
<---> Ocean surfaces
in late winter]**

(* Seasonal variations are generally much more pronounced at high latitudes that at low latitudes. The tropics do experience moderate seasonal variations, especially in rainfall, but they do not have the typical four seasons that we in the midlatitudes tend to think are standard everywhere.

(** Seasonal variations in ocean surface temperatures are generally much smaller than they are for land surfaces, but they can still be significant--say, for determining when hurricanes/typhoons/tropical cyclones occur.)

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