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<div class="">Hi Tim,</div>
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<div class="">As I said in the earlier correspondences, it appears <span style="font-size: 12.8px;" class="">GND_GPS_VTEC is </span><font size="2" class="">designed</font><span style="font-size: 12.8px;" class=""> for GITM for </span><font size="2" class="">hypothetical</font><span style="font-size: 12.8px;" class=""> data.</span></div>
<div class=""><span style="font-size: 12.8px;" class="">It integrates the electron density vertically within the model domain (up to ~500 km), but </span><span style="font-size: 12.8px;" class="">In reality, VTEC observations </span></div>
<div class=""><span style="font-size: 12.8px;" class="">include the contribution of plasma density above 500-700km. </span></div>
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<div class="">I and some of my collaborators use CHAMP_DENSITY to assimilate in-situ neutral mass density data.</div>
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</span></div>
<div class=""><span style="font-size: 12.8px;" class="">VTEC is usually given in TECU, and TECU is defined as 10e+16/m2.</span></div>
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</span></div>
<div class=""><span style="font-size: 12.8px;" class="">O_N2 is a unit-less ratio (the column density of O above an altitude where the N2 column density is </span><span style="font-size: 12.8px;" class="">10e+17/cm2)</span><span style="font-size: 12.8px;" class="">,</span></div>
<div class=""><font size="2" class="">ranging</font><span style="font-size: 12.8px;" class=""> from 0 to infinity, but typical values go up to ~1.5 or so.</span></div>
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<div class="">Tomoko</div>
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<div class="">On May 19, 2016, at 1:08 PM, Tim Hoar <<a href="mailto:thoar@ucar.edu" class="">thoar@ucar.edu</a>> wrote:</div>
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<div dir="ltr" class="">Hello all ...
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<div class="">I am interested in hearing from anyone/everyone who uses the obs_def_upper_atm_mod.f90</div>
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<div class="">I need to know who is using it - for what kinds of observations - and where those observations come from (so I can test my changes).</div>
<div class="">I'm trying to ensure the forward operators for</div>
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<font face="monospace, monospace" class="">SAT_RHO, KIND_DENSITY<br class="">
GND_GPS_VTEC, KIND_GND_GPS_VTEC<br class="">
CHAMP_DENSITY, KIND_DENSITY<br class="">
MIDAS_TEC, KIND_VERTICAL_TEC<br class="">
SSUSI_O_N2_RATIO, KIND_O_N2_COLUMN_DENSITY_RATIO</font>
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<div class="">work correctly across a variety of models. To do this, I need to know the units of the observations,</div>
<div class="">and ensure that the models provide <span style="font-family:monospace,monospace" class="">get_expected_upper_atm_density(),</span></div>
<div class=""><span style="font-family:monospace,monospace" class="">get_expected_vtec(), </span><span style="font-family:monospace,monospace" class="">get_expected_gnd_gps_vtec(), and </span><span style="font-family:monospace,monospace" class="">get_expected_O_N2_ratio()</span></div>
<div class="">the proper quantities. I have no reason to believe they are wrong, but the way they are written now</div>
<div class="">prevents TIEGCM from assimilating <span style="font-family:monospace,monospace" class="">GND_GPS_VTEC observations.</span></div>
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<div class="">I also don't know if anyone is using 'CHAMP_DENSITY' observations, particularly since the </div>
<div class="">observations/CHAMP/CHAMP_density_text_to_obs.f90 converter creates 'SAT_RHO' observations.</div>
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<div class="">If you, or anyone you know, is using or is planning on using obs_def_upper_atm_mod.f90, I'd like to hear from you.</div>
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<div class="">Thanks -- </div>
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<div dir="ltr" class="">Tim Hoar
<div class="">Data Assimilation Research Section<br class="">
<div class="">Institute for Mathematics Applied to Geosciences</div>
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<div class="">National Center for Atmospheric Research</div>
<div class=""><a href="mailto:thoar@ucar.edu" target="_blank" class="">thoar@ucar.edu</a></div>
<div class="">303.497.1708</div>
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