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<p><font face="Helvetica, Arial, sans-serif" size="-1">Dear UNAVCO
members,</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">Nevada
Geodetic Lab would like to announce public availability to over
34,000,000 station-days of tropospheric products (total zenith
delay, north gradient, east gradient, every 5 minutes since
1996.0) from over 16,000 stations.</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">The files are
available here:</font></p>
<font face="Helvetica, Arial, sans-serif"> </font>
<p><font face="Helvetica, Arial, sans-serif" size="-1"> <a
class="moz-txt-link-freetext"
href="ftp://gneiss.nbmg.unr.edu/trop">ftp://gneiss.nbmg.unr.edu/trop</a></font></p>
<font face="Helvetica, Arial, sans-serif"> </font>
<p><font face="Helvetica, Arial, sans-serif" size="-1"> </font></p>
<font face="Helvetica, Arial, sans-serif"> </font>
<p><font face="Helvetica, Arial, sans-serif" size="-1"> There are
single station-day files in directories year/day.</font><font
face="Helvetica, Arial, sans-serif" size="-1"> <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">File names
are compressed using gzip, and follow the IGS standard and look
a like RINEX filenames, for example, ALBH0010.96zpd.gz -- please
see the IGS SINEX Tropo format at the IGS Central Bureau for
more information. <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">If you have
not used IGS SINEX tropo format before, a single-line Linux
command can parse out the troposphere data into text columns,
e.g.,<br>
</font><font size="-1"><tt><br>
</tt></font><tt>zgrep -A1000 -m1 '^[+-]TROP/SOLUTION' </tt><tt>ALBH0010.96zpd.gz
</tt><tt>| tail -n+3</tt><font face="Helvetica, Arial, sans-serif"
size="-1"><br>
<br>
which should give 288 lines (5-minute epochs) of output. This
command extracts the block of data between lines starting with
+TROP/SOLUTION and -TROP/SOLUTION, while cutting out the header
(using tail). The columns descriptions can be found as
comments in the files themselves, as well as in a
machine-readable SINEX metadata block.<br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1"> We will be
working to make these visible on our web page soon at <a
class="moz-txt-link-freetext" href="http://geodesy.unr.edu">http://geodesy.unr.edu</a>,
as well as making the data directly available through http
links, and through the UNAVCO Plug and Play portal.<br>
</font></p>
<font face="Helvetica, Arial, sans-serif"> <font size="-1"> </font>
</font>
<p><font face="Helvetica, Arial, sans-serif" size="-1">They will now
continue to be updated weekly with new incoming data, as well as
newly discovered stations (~1000 new stations per year).</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">Those of you
familiar with our products already will know we have for many
years produced position solutions for a variety of latencies and
averaging intervals, from near real-time 5-minute solutions to
final 24-hour solutions. These tropospheric products were
generated in response to several user requests, and as an
unplanned "deliverable of opportunity" for our Plug and Play
Project in collaboration with UNAVCO which just came to an end.<br>
</font></p>
<font face="Helvetica, Arial, sans-serif"> <font size="-1"> </font>
</font>
<p><font face="Helvetica, Arial, sans-serif" size="-1">Your comments
and advice would be appreciated.</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">Thanks to
JPL/Caltech for providing the GIPSY software and orbit and clock
products used to generate these solutions, and to the NASA
ACCESS Program for support.<br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">Thanks,<br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif" size="-1">- Geoff
Blewitt<br>
Nevada Geodetic Lab<br>
</font></p>
<pre class="moz-signature" cols="72">--
Geoff Blewitt, Professor
University of Nevada, Reno
<a class="moz-txt-link-freetext" href="http://geodesy.unr.edu">http://geodesy.unr.edu</a>
<a class="moz-txt-link-freetext" href="http://www.nbmg.unr.edu/staff/geoff.htm">http://www.nbmg.unr.edu/staff/geoff.htm</a>
"If we knew what we were doing, it wouldn’t be called research" - Albert Einstein</pre>
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