<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE></TITLE>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2900.3527" name=GENERATOR></HEAD>
<BODY><!-- Converted from text/plain format -->
<H2><A title="Explore Earth’s Ionosphere with Google Earth"
href="http://www.universetoday.com/2008/04/30/explore-earths-ionosphere-with-google-earth/"><FONT
face=Verdana color=#467aa7>Explore Earth’s Ionosphere with Google
Earth</FONT></A></H2>
<DIV class=entry>
<P>Written by <A title="Posts by Ian O'Neill"
href="http://www.universetoday.com/author/ian/"><FONT color=#467aa7>Ian
O'Neill</FONT></A></P>
<P><A
href="http://www.universetoday.com/wp-content/uploads/2008/04/ionosphere.jpg"><FONT
color=#467aa7><IMG class="alignleft size-thumbnail wp-image-13986" height=166
alt="Computer generated image of the density of electrons in the ionosphere (Cathryn Mitchell, University of Bath)"
src="http://www.universetoday.com/wp-content/uploads/2008/04/ionosphere-250x166.jpg"
width=250></FONT></A><BR><FONT face=Verdana>The ionosphere is the final layer of
atmosphere before space. This highly dynamic region is constantly exposed to the
full intensity of </FONT><A class=alinks_links title=""
onclick="return alinks_click(this);"
href="http://www.universetoday.com/guide-to-space/the-sun/" rel=external><FONT
face=Verdana color=#467aa7>the Sun</FONT></A><FONT face=Verdana>, harsh
ultraviolet radiation breaking down molecules and atoms. Highly charged ions and
free electrons therefore fill the ionospheric layers. Critical to terrestrial
communications, the ionosphere also plays host to the largest lightshow on
</FONT><A class=alinks_links title="" onclick="return alinks_click(this);"
href="http://www.universetoday.com/guide-to-space/earth/" rel=external><FONT
face=Verdana color=#467aa7>Earth</FONT></A><FONT face=Verdana>, the Aurora. Now
NASA-funded research has developed a <EM><STRONG>live</STRONG></EM> “4D
Ionosphere” plugin for Google Earth. <EM>Now you can fly through the
atmosphere’s uppermost reaches without even leaving your desk…</EM><BR><SPAN
id=more-13985></SPAN><BR>The ionosphere is highly important to us. Radio
operators will be acutely aware about how the ionosphere influences radio wave
propagation. Ever since Guglielmo Marconi’s experiments with trans-Atlantic
radio communications in 1901 between England and the US, the ionosphere has
influenced our ability to communicate over large distances, and without the aid
of modern satellite technology. The ionosphere creates a charged, reflective
barrier that radio waves can be bounced off (bypassing the blocking effect of
the curvature of the Earth). However, radio signals are highly influenced by
variations in the ionosphere and can be “blacked out” should a major </FONT><A
class=alinks_links title="" onclick="return alinks_click(this);"
href="http://www.universetoday.com/guide-to-space/the-sun/solar-storm/"
rel=external><FONT face=Verdana color=#467aa7>solar storm</FONT></A><FONT
face=Verdana> pump charged particles into the magnetosphere and ionosphere. Even
modern Global Positioning Satellite (GPS) signals are influenced by this
atmospheric layer, reflecting and attenuating radio waves. As aircraft, ships
and other modes of transport now depend on GPS positioning, it is essential that
we fully comprehend the physics behind the ionosphere. </FONT></P>
<P><A
href="http://www.universetoday.com/wp-content/uploads/2008/04/screenshot.jpg"><FONT
face=Verdana><IMG class="alignleft size-thumbnail wp-image-13994" height=191
alt="A screenshot of Google Earth, with ionosphere overlaid (Google)"
src="http://www.universetoday.com/wp-content/uploads/2008/04/screenshot-250x191.jpg"
width=250></FONT></A></P>
<P><FONT face=Verdana>In the aim to have a better grasp of the state of the
ionosphere, a “live” plugin for Google Earth has just been announced. Funded by
NASA’s Living With a Star (LWS) program, it is hoped that this tool can be used
by the public and professionals alike to see the current state of the electron
content of the ionosphere. Once downloaded and running, the viewer can rotate
the globe and see where electron density is high and where it is low. In dense
regions, it is very hard for radio waves to propagate, signifying that radio
quality will be poor, or blocked all together. In Google Earth, these regions
are highlighted in red. The blue regions show “normal” radio propagation
regions, expect good quality signal in those locations.</FONT></P>
<P><FONT face=Verdana>The reason why this new system has been dubbed “4D
Ionosphere” is that you can view the ionosphere in three spatial dimensions, and
the data is refreshed every ten minutes to give the extra time
dimension.</FONT></P>
<UL>
<LI><STRONG><A
href="http://terra1.spacenvironment.net/%7Eionops/current_files/Google_TEC.kml"><FONT
face=Verdana color=#467aa7>Download the .kml “4D Ionosphere” Google Earth
plugin »</FONT></A></STRONG><FONT face=Verdana> </FONT>
<LI><STRONG><A
href="http://svs.gsfc.nasa.gov/vis/a010000/a010200/a010208/Ionoshpere_WebShort_320x240.mp4"><FONT
face=Verdana color=#467aa7>View video tutorial of how to use “4D Ionosphere”
(19MB .mp4 video) »</FONT></A></STRONG><FONT face=Verdana> </FONT>
<LI><STRONG><A href="http://earth.google.com/"><FONT face=Verdana
color=#467aa7>Download Google Earth »</FONT></A></STRONG><FONT face=Verdana>
</FONT></LI></UL>
<P><FONT face=Verdana>This isn’t the first time Google Earth has been used by
organizations for space-based research. </FONT><A
href="http://www.universetoday.com/2008/02/24/space-debris-may-be-catastrophic-to-future-missions-and-google-earth-is-watching/"><FONT
face=Verdana color=#467aa7>On February 24th, I reported</FONT></A><FONT
face=Verdana> that a plugin had been released to track the space debris
currently orbiting our planet. Nancy also </FONT><A
href="http://www.universetoday.com/2008/03/14/google-sky-takes-you-there/"><FONT
face=Verdana color=#467aa7>gave the new Google Sky a test drive</FONT></A><FONT
face=Verdana> in March, a great way to learn about astronomy through this user
friendly interface.</FONT></P>
<P><FONT face=Verdana>I can see lots of applications for this tool already.
Firstly I’d be very excited to compare the ionosphere during periods of high
</FONT><A class=alinks_links title="" onclick="return alinks_click(this);"
href="http://www.universetoday.com/guide-to-space/the-sun/solar-activity/"
rel=external><FONT face=Verdana color=#467aa7>solar activity</FONT></A><FONT
face=Verdana> with periods when the Sun experiences </FONT><A class=alinks_links
title="" onclick="return alinks_click(this);"
href="http://www.universetoday.com/guide-to-space/the-sun/solar-minimum/"
rel=external><FONT face=Verdana color=#467aa7>solar minimum</FONT></A><FONT
face=Verdana> (like now). This would be especially exciting in Polar Regions in
the auroral zone when high quantities of </FONT><A class=alinks_links title=""
onclick="return alinks_click(this);"
href="http://www.universetoday.com/guide-to-space/the-sun/solar-wind/"
rel=external><FONT face=Verdana color=#467aa7>solar wind</FONT></A><FONT
face=Verdana> particles ignite aurorae. Also, there are possible applications
for amateur radio (ham) operators who could use this as a means to forecast the
strength of the radio signal during campaigns. I am however uncertain how
accurate or how detailed these measurements will be, but it at least gives a
very interesting look into the current state of this interesting region of the
atmosphere.</FONT></P>
<P><FONT face=Verdana>Fonte: </FONT><A
href="http://science.nasa.gov/headlines/y2008/30apr_4dionosphere.htm?list1088553"><FONT
face=Verdana color=#467aa7>NASA</FONT></A></P></DIV></BODY></HTML>