Hill
Master Guide
Reged: 10/31/04
Posts: 9222
Loc: Southern California
|
|
If you check the Weather layer Information section you will find the following text which explains it more thoroughly and accurately than I originally did.
Quote:
Clouds
Since the 1960s, the capability to view Earth's cloud patterns from space has been made possible from two main types of environmental satellites, geostationary Earth-orbiting and low Earth-orbiting satellites. At least five geostationary satellites positioned around the equator are capable of providing depictions of global weather patterns, updated every hour. From their vantage point 36,000 km above the equator, the sensors onboard geostationary satellites can't quite 'see'the very high latitudes near the north and south poles. Since their orbit flies over the high latitude regions over the north and south poles typically every 90 minutes, low Earth-orbiting satellite imagery is well-suited to complement the geostationary imagery and thereby provide total global coverage. Even so, such satellite data merging is complicated by the fact that each individual satellite observation represents a single 'snapshot' of the cloud patterns, each taken at slightly different times, whereas the underlying clouds themselves are constantly moving and evolving.
In this depiction of global clouds, these satellite data are processed to discriminate clear (transparent) and cloudy areas. For cloudy areas, the brightness is approximated based upon the cloud top temperature relative to the surface temperature, as a proxy for the height of each cloud pixel. Due their location near the Earth's surface, low level clouds such as stratocumulus and stratus (fog) clouds may be poorly represented.
For more information, visit the Naval Research Laboratory (NRL) Marine Meteorology Division.
( http://www.nrlmry.navy.mil/sat-bin/global.cgi )
Bold emphasis mine. So the parts of the imagery missed will vary according to particularly the orbits of the low altitude satellites. Data nearer the equator, where most weather imagery of consequence to most populated areas will be captured at all times by the 5 geostationary satellites at high altitude over the equator.
|
turak2008
First Post
Reged: 10/08/08
Posts: 1
|
|
Open-minded about this. Have been taking snapshots. Feel free to share analysis. http://www.flickr.com/photos/omsar2008/
|
Hill
Master Guide
Reged: 10/31/04
Posts: 9222
Loc: Southern California
|
|
It's best to read long threads in "flat" mode. That way you can see all contributions, one or more of which may answer your question.
|
Nancy_S
Tourist
Reged: 08/10/06
Posts: 80
|
|
Some new age sites are claiming that it is ufos and a sign from G-d that the end is near: http://www.fivedoves.com/letters/oct2008/markc1015.htm
http://www.fivedoves.com/letters/oct2008/rene1016-4.htm
http://www.weatheroffice.gc.ca/satellite/composite_disclaimer_e.html
Canadian Arctic Composite Disclaimer
Data on this composite image ranges in time from that given by the header to several hours old.
This composite starts fresh each day with the data from the first pass of day placed on the map. The first pass typically covers the easterly portion of the map. Through the day new data replaces sections of old data or fits in areas not previously covered. The time between the newest and oldest data may by 4 - 6 hours. By midday most of the map is covered and some areas have had old data replaced several times. By end of day all but sections of east Greenland have data.
http://www.upi.com/Security_Industry/200...198682331/print
Outside View: Arctic satellite balance
By YURY ZAITSEV
UPI Outside View Commentator
Published: Dec. 26, 2007 at 10:18 AM
MOSCOW, Dec. 26 (UPI) -- Russian space industry experts are currently discussing the concept of a federal program to use the results of space research to aid national socioeconomic development.
The program envisions using a new satellite cluster, called "Arktika," to monitor weather conditions in the polar regions. President Vladimir Putin, who advocates the program, learned more about the new orbital system during his recent visit to the Lavochkin Research and Production Association -- NPO -- near Moscow.
Anatoly Perminov, director of the Federal Space Agency, Roskosmos, said Arctic research was highly important. In the last 15 years the national aerospace environmental monitoring system for the Arctic has virtually ceased to exist. The lack of authentic and up-to-date regional information makes it impossible to compile accurate weather forecasts for northern Russia and the world.
Major errors in statistical weather forecasts can be explained by initial data discrepancies. Most initial weather data for the Arctic regions comes from international geostationary satellites, which cannot effectively scan the Earth's high latitudes. Their angles of observation do not exceed 70 degrees, meaning they cannot effectively observe higher than 60 degrees of latitude north.
Nor are geostationary-satellite communications channels able to receive complete data from Arctic buoys and automatic weather stations. The Lavochkin NPO proposes to solve these problems by developing the highly elliptical weather-satellite system that would provide a picture of Arctic conditions.
Article Continues
|
abaraba
Tourist
Reged: 10/25/08
Posts: 6
|
|
first of all - im not afraid of aliens, im afraid of humans!
//---------------------------------------------------------------------------------------
MY ONLY POINT: whatever this is - IT IS NOT EXPLAINED
A.) this is not caused by "field of view" of camera, it would not look like that AT ALL
B.) its not "missing data" - it would not look like that AT ALL
C.) its HARDLY a software bug, its too "clean" ..but if it is, than Google must EXPLAIN IT
--- ARGUMENT ---
this is HOW its SUPPOSED to BE and how it WAS:
http://www.barnabu.co.uk/monthly-global-cloud-sequences-in-google-earth/
you only have to see that and compare it to the last month, that's all
no field of view, no statistical error, no missing data..
more info1:
//---------------------------------------------------------------------
ok, so even on the 1st picture its clear that this is not "missing data", you can see even there that satellite could see inside and all around that cloud (right above polar elephant ;-)
but, with second picture it seems it was actually a cloud that had these sharp edges, now almost all smudged
in any case its clear that there is no "loss of data" or "field of vision error" here
- does everyone agree?
cheerio,
gameBoX Linux
|
Hill
Master Guide
Reged: 10/31/04
Posts: 9222
Loc: Southern California
|
|
I can see that there is a difference in the way clouds used to be displayed compared to the way the cloud layer is displayed now. Being a moderator I'm not privy to the inner workings of the cloud layer. I do know that the polar regions have always been a challenge to terrestrial mapping and to any imagery draped over the poles. Just try creating an overlay near the polar regions, and forget about it directly over the poles! Data is always quirky at the poles due to the old "peeling-the-orange-and-getting-a-flat-map-out-of-it" problem.
Standard and skewed imagery of the same area. The second image has had all of its southern pixels crammed into one point, as happens at the poles.
I think what you see is a different solution to the problem, which itself may be replaced with another solution later on. Whatever you try will cause problems at the poles. Since very few have an interest in polar cloud cover, the imagery team probably just does not have that as a high priority.
 
North (top) and South polar imagery from barnabu's website. This shows only clouds and no other imagery to make it easier to see the holes in the imagery at the poles, and even some distance away from the poles the imagery is smeared. I believe this indicates all of the imagery here is from equatorial satellites.
|
Previous
Index
Next
Threaded
[Re: 
Edit
Reply
Quote
