2011-10-09 10:57:05Every Picture Tells A Story - Updated
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

See below for update.

2011-10-10 18:24:16
skywatcher

andycasely@hotmail...
122.107.164.176

Interesting animation.  It's difficult to see from the animation, but does the presence of NH snowcover cause a delay in the progression of the 'balance point' of the net flux as it progresses northwards through the NH spring? (in other words, does the net flux move to positive values earlier in the SH spring than the NH spring?)  I was trying to see if I could note a difference between NH and SH patterns.  If there is a delay, then in a warming/reduced snow cover NH the net flux would more rapidly switch from negative to positive, or switch earlier in the spring, part of the albedo feedback.  But the ocean/continent mix may make such a comparison impossible.

2011-10-12 03:25:12
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Could you put this in a blog post page, Daniel?  And do you think it's ready for prime time?  Looks good to me.

2011-10-12 06:30:37
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
24.213.18.68

I'll put up a post tonight, dana.  Want to polish it a bit first. 

Will put up a linky here when revised.

 

Sky, I'm probably going to put in some links to SkS posts that may already address your questions.

2011-10-12 21:27:36
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

Sorry guys.  Solo-dad this week; didn't get to it last night.

2011-10-13 02:32:21
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

No prob Daniel, just give a heads-up whenever it's ready.  Rob's got 2 ready to go, and I've got one in review, so no big rush.

2011-10-13 14:12:29
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

Post is here:

http://www.skepticalscience.com/Every_Picture_Tells_A_Story.html


Every Picture Tells A Story

Posted on 17 October 2011 by Daniel Bailey

It is said that a picture tells a thousand words.  And, as we all know, every picture tells a story.  By extension, movies tell thousands of stories.

The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models.

Snow

Fig 1.  Snow cover, 2006-2011


Net Radiation

Fig 2.  Net radiation, 2006-2011

(Click here for the full-sized animation)

Snow Cover & Net Radiation

Earth's climate, including its average surface temperature, depends on the balance between incoming and outgoing energy. Energy comes in to the system when sunlight penetrates the top of the atmosphere. Energy goes out in two ways: reflection by clouds, aerosols, or the Earth's surface; and thermal radiation — heat emitted by the surface and the atmosphere, including clouds. The balance between incoming and outgoing energy is called net flux. Snow on the ground can dramatically change Earth's net flux by increasing the amount of sunlight the ground reflects.

The snow cover map shows the fraction of an area covered by snow on a monthly basis. Measurements were made by the MODIS sensor on NASA's Terra satellite. Gray indicates land areas with no snow, darkest blue represents minimal snow cover, and solid white indicates 100 percent snow cover. Because MODIS relies on visible light to assess snow cover, the sensor cannot collect data over the highest latitudes of the Northern Hemisphere during winter when no sunlight reaches the polar region.

The map of net flux shows monthly changes in the balance of incoming and outgoing energy on Earth as measured by the Clouds and the Earth Radiant Energy System (CERES) sensor on NASA's Terra and Aqua satellites. Places where the amounts of incoming and outgoing energy were in balance are yellow. Places where more energy was coming in than going out (energy surplus) are red. Places where less energy was coming in than going out (energy deficit) are blue-green.

The most obvious pattern in both maps is the way they both change with the seasons. The comparison starts in late summer in the Northern Hemisphere. As the September equinox approaches, a zone of positive net flux (more energy coming in than going out) is nearly centered over the equator. As the season changes into winter, Northern Hemisphere snow cover increases. Meanwhile, the zone of positive net flux shifts to the Southern Hemisphere , and a swath of negative net flux (more energy going out than coming in) appears in the high latitudes of the Northern Hemisphere. The pattern reverses on the March equinox.

The influence of snow cover on net flux is most clearly demonstrated in areas of permanent snow cover: Greenland and Antarctica. Snow is so reflective that even on the December and June solstices — when alternate hemispheres are receiving the maximum amount of direct sunlight they will receive all year — the net flux of these permanently snow-covered places is still zero or slightly negative. In December, the Southern Ocean surrounding Antarctica has an energy surplus (red): it is absorbing more energy from incoming sunlight than it is reflecting or emitting as heat. But Antarctica itself remains yellow, which means that incoming and outgoing energy are in balance. This balance is possible because the snowy surface reflects so much more incoming sunlight than the dark blue waters of the ice-free ocean. A similar pattern appears over Greenland in June, when the surrounding area is red (energy surplus) while Greenland itself is yellow-green (slightly negative net flux).

Snow

Fig 3.  Annual Mean NH Snowfall Extent (Rutgers University Global Snow Lab)

Just For Fun

Aurora

Fig 4.  NH Aurora Borealis (NOAA POES satellite); SH here.

Related Links

  1. 2009-2010 winter saw record cold spells
  2. 2010 - 2011: Earth's most extreme weather since 1816?
  3. 2009-2010 winter saw record cold spells
  4. New Zealand Snow No Show = No Jobs
  5. Ocean Heat Content And The Importance Of The Deep Ocean
  6. Record high snow cover was set in winter 2008/2009
  7. Tamino on Regime Change
  8. Tamino on Snow
  9. Trenberth on Tracking Earth’s energy: A key to climate variability and change
  10. Why Wasn't The Hottest Decade Hotter?
2011-10-13 14:29:09
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.101.55

I like it - going live because we haven't published anything for a while.  If i'm jumping the gun, feel free to give me a slap and take it down :-)

2011-10-13 14:43:12
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

Nah; I just put some extra stuff only marginally related in at the end.  Probably could have left off the last 2 graphics.

Meh.