The retreat of sea ice in the Arctic Ocean is diminishing Earth's albedo, or reflectivity, by an amount considerably larger than previously estimated, according to a new study that uses data from instruments that fly aboard several NASA satellites.
The study, conducted by researchers at Scripps Institution of Oceanography, at the University of California, San Diego, uses data from the Clouds and Earth's Radiant Energy System, or CERES, instrument. There are CERES instruments aboard NASA's Tropical Rainfall Measurement Mission, or TRMM, satellite, Terra, Aqua and NASA-NOAA's Suomi National Polar-orbiting Partnership (Suomi NPP) satellites. The first CERES instrument was launched in December of 1997 aboard TRMM.
As the sea ice melts, its white reflective surface is replaced by a relatively dark ocean surface. This diminishes the amount of sunlight being reflected back to space, causing Earth to absorb an increasing amount of solar energy.
Arctic Surface Darkening Faster
This image shows a visualization of Arctic sea ice cover on Sept. 12, 2013, with a yellow line showing the 30-year average minimum extent. A new study shows that the magnitude of surface darkening in the Arctic (due to the retreat of sea ice) is twice as large as that found in previous studies.
Image Credit: NASA Goddard's Scientific Visualization Studio/Cindy Starr
The Arctic has warmed by 3.6 F (2 C) since the 1970s. The summer minimum Arctic sea ice extent has decreased by 40 percent during the same time period. These factors have decreased the region's albedo, or the fraction of incoming light that Earth reflects back into space – a change that the CERES instruments are able to measure.
Scripps graduate student Kristina Pistone and climate scientists Ian Eisenman and Veerabhadran Ramanathan used satellite measurements to calculate Arctic albedo changes associated with the changing sea ice cover. Albedo is measured as a percentage. A perfectly black surface has an albedo of zero percent and a perfectly white surface has an albedo of 100 percent. The albedo of fresh snow is typically between 80 and 90 percent whereas the albedo of the ocean surface is less than 20 percent. Clouds and other factors, like aerosols and black carbon, also influence the albedo of Earth.
The researchers calculated that the overall albedo of the Arctic region fell from 52 percent to 48 percent between 1979 and 2011. The magnitude of surface darkening is twice as large as that found in previous studies. They also compared their results to model simulations to assess the capability of computer models to portray and forecast albedo changes.
Previous studies have used a combination of computer models and observations in their calculations to estimate how much extra energy has been absorbed by the oceans. In contrast, the Scripps team opted to directly correlate albedo measurements made by NASA's CERES instrument data with observations of sea ice extent made by the Special Sensor Microwave Imager (SSM/I) radiometers aboard Defense Meteorological Satellite Program satellites. This approach avoided the possibility of systematic issues in computer models.
"It's fairly intuitive to expect that replacing white, reflective sea ice with a dark ocean surface would increase the amount of solar heating," said Pistone. "We used actual satellite measurements of both albedo and sea ice in the region to verify this and to quantify how much extra heat the region has absorbed due to the ice loss. It was quite encouraging to see how well the two datasets – which come from two independent satellite instruments – agreed with each other."
The National Science Foundation-funded study appears in the journal Proceedings of the National Academy of Sciences 45 years after atmospheric scientists Mikhail Budyko and William Sellers hypothesized that the Arctic would amplify global warming as sea ice melted.
Article reprinted from http://www.nasa.gov/content/goddard/nasa-satellites-see-arctic-surface-darkening-faster/index.html#.Uwk00fldWSo
April, 2006
HEATHER NOVA - ONLINE MAGAZINE
April 19, 2006
Welcome
on the Heather Nova Online Magazine, the place on the Internet where
you can find all the information you want with a simple click of your
mouse.
We're a nonprofit organization and try to offer you the
best on the net and we provide you with lots of information about your
idol & our figure head : Heather Nova, the shining star from
Bermuda.
Heather is coming to the Bredase turfschip, sorry, mistake, i mean the trojan horse (Paard van Troje) in The Hague www.paard.nl on august 2: tickets already available, national ticket selling starts march 25.
Kirsty Cotten (Ashley
Laurence) is now grown up and married to Trevor Gooden (Dean Winters).
Her memory of the events that took place back at her parent's home and
the mental institution have dimmed, but she is still traumatized. One fateful
day, the two get into a fatal car crash, killing Kirsty. Now, Trevor finds
himself in a strange world full of sexy women, greed and murder, making
him believe he may be in hell. He follows the clues all the way to Pinhead
(Doug Bradley). Read
more...
Strangeland
In a teen chat room,
Genevieve Gage (Linda Cardellini), the teenager daughter of detective Mike
Gage (Kevin Gage) is invited to a blind date by the cool Capt Howdy (Dee
Snider). The guy is indeed a pierced a schizophrenic sick and sadistic
maniac, and he kidnaps Genevieve and her friend Tiana Moore (Amal Rhoe).
He submits the girls and other adolescents to tortures. When the body of
Tiana is found, Mike hunts Capt Howdy and puts him in jail first and then
he is sent to a mental ...
A country family of
five takes in cousin Julia, whose parents recently perished in a car crash.
Julia extends her influence over the family and those around them, fooling
all except for Rachel, the teenaged girl who knows her cousin is up to
no good.
This movie was a terrible mistake from me buying it. Don't make
the same mistake as I did since this movie is a complete waste of time.
This is a fairly morbid
yet emotional war drama, starring Caper Van Dien and Carrie Otis. It is
about a group of ex vietnam soldiers re-visiing aold battle gorunds years
after the war. THye re-live memories of the war and remember things that
they had tried to forget.
The film doesn't delve into the cliche bucket to many times as war films
usually do and the script is fairly good. The actors perform well in some
good roles but Casper Van Dien, who...
Bobby Platt is a
mentally slow young man who escapes an abusive, hateful stepfather who
has killed his pets one by one. To save himself, Bobby runs away and meets
a strange old man who wanders the highways to bury roadkill animals. Bobby
becomes the old man's apprentice and learns to see the world of nature
in a strange idyllic way. But soon the shadow of his stepfather catches
up to him and Bobby's world explodes into a grotesque nightmare.
...
Go to the section "Video" to find out
more. Here you can watch some trailers too if you want
The New York Times Headlines
Go to the section "News, New York Times" to read the free and current New York Times newsletter.
A new column: World Travel Stories
We had a column titled "Spam" and decided to replace the column with "World travel stories". Go to the section "World travel stories" to read the travel stories.
If
you want to share your travel story with us, or if you want to promote
your hometown, than send an email to the editor. You can send your
holiday photos too! Write to cynthia@heathernova.info
Do you want to exchange links with us? Send an email with a description of your site to letters@heathernova.info
We only place links from sites that link our site too!
P.S. every site and homepage listed on our site will be automaticly added to our search engine and search engines worldwide.
New members
There's a new member on our mailing list, his username is Rocketboy.
Rocketboy wrote:
The
Internet is a marvelous thing. Over the past year, I have been
listening to streaming audio and have discovered a number of artists
who I like a lot. I have bought more albums in the last year than in
the previous five, simply because I have found so many great ones.
Heather
is the best surprise of all. I had no idea she had been around for ten
years already and released so many albums. I am a big Tori Amos fan,
and Heather is the closest I have ever found to that level of talent --
inventive writing, interesting themes, and tremendous skill in live
performances (very few artists I have heard are as good live as they
are
in the studio).
Looking forward to hearing more about her, and hoping that someday she will be
able to tour here in the U.S. where I can actually see her (I am on the West Coast).
Well
Rocketboy, you're more than welcome and btw Heather will do a song in
the states if I can believe Sakis P, see previous message and we from
the HN Online Magazine hope that it will come true and more than that.
We hope that Heather will do a real tour in the states, but she need your support.
I
would like to say one thing to the visitors of our site, living in the
states: please, become a member of the mailing list and let us know
your point of view. And you know the saying: the more the merry :-)
Don't wait any longer, become a member too and go to the section "Mailing list". Stay in touch with other fans and best of all: a membership is free! Or become an editor for the .info site.
Do you have questions? Mail them to me, I will be glad to answer them!
RIVERSIDE, IOWA: Critic Doctor
visits Riverside, Iowa and invades the set of William Shatner's
new Spike TV show "Invasion Iowa." Shatner fooled the
townspeople into thinking they were filming a Hollywood movie.
Turns out the people are now the unwitting stars of their own
reality TV show! More to come!
Content
Provided by Criticdoctor.com Copyright 2004
by Herb Kane. All rights reserved.
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PART ONE