[Dart-dev] [4902] DART/trunk/observations/observations.html: Add some paragraphs from an old file which talk about synthetic

[nancy at ucar.edu]

Revision: 4902
Author:   nancy
Date:     2011-05-10 09:32:27 -0600 (Tue, 10 May 2011)
Log Message:
-----------
Add some paragraphs from an old file which talk about synthetic
observations, and add pointers to PMO and create_obs_sequence.

Modified Paths:
--------------
    DART/trunk/observations/observations.html

-------------- next part --------------
Modified: DART/trunk/observations/observations.html
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--- DART/trunk/observations/observations.html	2011-05-06 23:05:40 UTC (rev 4901)
+++ DART/trunk/observations/observations.html	2011-05-10 15:32:27 UTC (rev 4902)
@@ -42,14 +42,20 @@
 can be used to convert data from a variety of native
 formats into a common DART 
 <em class=code>observation sequence</em> format.
-<br>
-<br>
+</P><P>
+Synthetic observations are those not based on an actual instrument reading of
+a system, but instead are fabricated to have a known value, or have values
+computed by running a model, possibly with a fixed amount of simulated noise
+added. These observations can be used for testing, determining the
+sensitivity of the model to assimilation, and for designing new observation systems.
+The DART system includes several ways to create synthetic observations.
+See the <a href="#Programs">Programs</a> section below for more details.
+</P><P>
 The DART framework enforces a clean separation between observations
 and the models they are assimilated into.  The same observations can be
 used in any model which understands how to generate a value for the requested
 type of observation from its state space values.
-<br>
-<br>
+</P><P>
 In many cases a single, self-contained program can convert 
 directly from the observation
 location, time, value, and error into the DART format.  In other cases,
@@ -57,13 +63,11 @@
 there is a two-step process with two programs and an ASCII intermediate file.
 We are currently leaning towards single-step conversions but either
 approach can be used for new programs.
-<br>
-<br>
+</P><P>
 In many cases, the original datasets are in a standard scientific
 format like netCDF, HDF, or BUFR, and library routines for those
 formats can be used to read in the original observation data.
-<br>
-<br>
+</P><P>
 The DART software distribution
 includes Fortran subroutines and functions to help create
 a sequence of observations in memory, and then a call to the 
@@ -281,14 +285,29 @@
 format requried by DART.  In addition this external program produces
 DART observation sequence files:
 <ul>
-    <li><a href="http://code.google.com/p/opaws/"
-         >Observation Processing And Wind Synthesis (OPAWS)</a>:
-         OPAWS can process NCAR Dorade (sweep) and NCAR EOL Foray (netcdf) radar data.
-         It analyzes (grids) data in either two-dimensions (on the conical surface of
-         each sweep) or three-dimensions (Cartesian). Analyses are output in netcdf,
-         Vis5d, and/or DART (Data Assimilation Research Testbed) formats.
-    </li>
+<li><a href="http://code.google.com/p/opaws/">
+     Observation Processing And Wind Synthesis (OPAWS)</a>:
+     OPAWS can process NCAR Dorade (sweep) and NCAR EOL Foray (netcdf) radar data.
+     It analyzes (grids) data in either two-dimensions (on the conical surface of
+     each sweep) or three-dimensions (Cartesian). Analyses are output in netcdf,
+     Vis5d, and/or DART (Data Assimilation Research Testbed) formats.
+</li>
 </ul>
+</P><P>
+For generating synthetic observations, see the
+<a href="../obs_sequence/create_obs_sequence.html">create_obs_sequence</a> 
+program documentation.
+You can also generate observation files based on text input.  See the
+<a href="text/text_to_obs.html">text_to_obs</a> program documentation.
+Or for simulating a large complex observing system, you can use the
+DART library routines in a Fortran program to compute the observation
+information and have the DART routines write the output file.
+</P><P>
+See the 
+<a href="../perfect_model_obs/perfect_model_obs.html">perfect_model</a>
+program documentation on how to run a model with a set of observations
+that have only locations, types, and times, and have the forward operators
+compute the observation values.
 </P>
 
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