Dear Facundo,
No, the change at 7 km should not have any impact. I did a small test
myself. I used qpack2_demo and tested this
---
% Add a second measurement
%
Y(2) = Y(1);
%
Y(2).LONGITUDE = pi;
Y(2).ZA = 45;
% Add 0.5 ppm around 7 km:
Q.ABS_SPECIES(1).ATMDATA.DATA(10) = ...
Q.ABS_SPECIES(1).ATMDATA.DATA(10) + 0.5e-6;
% Calculate simulated spectra
%
Y = qpack2( Q, oem, Y ); % Dummy oem structure OK here
return
---
Note thr return, to avoid adding noise to the spectra.
That gave (just including result of first inversion)
>> qpack2_demo;
Simulating spectrum 1/2
Simulating spectrum 2/2
/--------------------------------------------------------------------\
| Inversion case 1 (of 2) |
| Gamma Total Profile Spectrum Converg. |
| Iteration factor cost cost cost measure |
| 1 NaN 0.000 0.00 0.00 NaN |
| 2 0.0 0.000 0.00 0.00 0.00 |
\--------------------------------------------------------------------/
That is, the disturbance had no impact. If I instead added 0.5 ppm at
altitude 20 (i.e. disturbing DATA(20)), I got:
>> qpack2_demo;
Simulating spectrum 1/2
Simulating spectrum 2/2
/--------------------------------------------------------------------\
| Inversion case 1 (of 2) |
| Gamma Total Profile Spectrum Converg. |
| Iteration factor cost cost cost measure |
| 1 NaN 0.118 0.00 0.12 NaN |
| 2 0.0 0.000 0.00 0.00 2.85 |
| 3 0.0 0.000 0.00 0.00 0.00 |
\--------------------------------------------------------------------/
That is, the "measurement" is disturbed from the a priori state.
I tested this both for v2.2 and v2.3, to be totally sure.
So, you must do something else in your test that gives a disturbance of
the spectrum. But I can not figure out what it can be. In any case, all
looked OK in my test.
Regards,
Patrick
On 01/15/16 09:16, Facundo Orte wrote:
> Dear Patrick,
> Thanks a lot for your reply.
> Related with the first suggestion, I interpolate the a-priori ozone
> profile and synthetic ozone profile to Q.P_GRID to be sure that dO3 is
> affecting only the altitud that I want to affect.
> Temperature and H2O are same in both cases and also all other parameters.
> I prepared a .pdf that I am sending attached to explain better which is
> the problem.
> I can not understand why ozone below Y.Z_PLATFORM is affecting my
> retrieval.
>
> Thank you so much.
> Regards
> Facundo
>
>
> 2016-01-14 16:46 GMT+09:00 Patrick Eriksson
> <[email protected] <mailto:[email protected]>>:
>
> Dear Facundo,
>
> What do you mean with "a little bit different"? A figure would have
> helped.
>
> As soon as you involve a retrieval in test of this kind, you need
> also to consider the retrieval grid. In this case, the O3 profile
> will be interpolated, from the retrieval grid to Q.P_GRID and only
> this can introduce some disturbance. To keep this "disturbance
> small", it is a good idea that the retrieval grid is sub-set of the
> P_GRID, such every second point in P_GRID. Or if you do a test like
> this, why not set the retrieval grid to P_GRID.
>
> Just to be clear, no change in the profile is totally local, it has
> an effect out to the adjecent grid points. But I assume that you
> have some grids points between 7 and 12 km, and this is not an issue
> here.
>
> Anyhow, a change of O3 at 7 km should not affect upward measurements
> at 12 km. Note that things can be different for temperature and H2O
> as these quantities affect hydrostatic equilibrium, and a local
> effect propagates through the atmosphere.
>
> Regards,
>
> Patrick
>
>
> On 01/14/16 07:14, Facundo Orte wrote:
>
> Dear Patrick and Ole Martin,
> I am writing again from this old mail because I have a problem
> in Qpack2
> that I think that it is related with the setting that Ole Martin
> proposed in the previous mail, but I am not sure.
> To explain it I want to share the experiment that I did:
>
> 1. I set Y.Z_PLATFORM=12Km. My O3 a-priori profile goes from
> ground to
> 90km (I will call it 'APRIORI') [So, then of the 3. step I will
> have a
> simulated spectrum from the a priori (SPECTRUM_AP)]
>
> 2. I make a synthetic profile (taking it as O3 in the atmosphere
> or true
> state vector)which is same as the a priori profile, but I add a
> delta O3
> (0.5ppm) at 7km (PROFILE_7km). So, I arrange a syntetic "true state"
> that I know. Then I calculate a spectrum (SPECTRUM_7km) from
> PROFILE_7km
> using QPack2/ARTS. I took this spectrum as the measurement.
>
> 3. I run Qpack2/ARTS inserting SPECTRUM_7km as measurement, and
> APRIORI
> as a priori profile and stop in the first iteration.
>
> (Note that I am setting Y.Z_PLATFORM=12km, and I the add a delta
> O3 the
> ozone in the true state vector at 7km. )
>
> The result was that SPECTRUM_AP (yf) is a little bit diferent to
> SPECTRUM_7km (y). I think that it must be equal (SPECTRUM_AP =
> SPECTRUM_7km) because the Y.Z_PLATFORM is above to 7km and a
> perturbation at 7km should not affect the retrieval. Is it correct?
>
> the Q is: Why changes below Y.Z_PLATFORM in the true state vector
> affect the retrieval?
>
> Thanks in advance.
> Best regards
> Facundo
>
>
>
>
>
>
>
> 2014-11-18 21:58 GMT+09:00 Ole Martin Christensen
> <[email protected]
> <mailto:[email protected]>
> <mailto:[email protected]
> <mailto:[email protected]>>>:
>
> Hi,
>
> the standard way of doing this is to do it before you do the
> retrieval. You manually adjust your measured spectra
> assuming that
> your measured opacity is correct (called "tropospheric
> correction").
>
> In arts you can then model your instrument as being above the
> troposphere, i.e. by setting the altitude of your sensor
> (Y.Z_PLATFORM if you use qpack2) to 15 km. The simulated
> spectra can
> then be compared to your corrected spectra for a successful
> retrieval.
>
> Another option is using continuum models to model O2,
> H2O(gas and/or
> liquid) across the tropopause. These can be added by adding by
> writing e.g.:
>
> Q.ABS_SPECIES(2).TAG = { 'H2O-PWR98' };
>
> With a following fields like Q.ABS_SPECIES(2).ATMDATA, and
> Q.ABS_SPECIES(2).GRIDS.
>
> However, in general the manual tropospheric correction is
> the most
> commonly used method, as it is simpler, and would recommend
> starting
> with this.
>
> If anything is unclear please feel free to send more
> questions. For
> further inquiries I would also strongly recommend the qpack
> and arts
> mailinglists.
>
> https://www.sat.ltu.se/mailman/listinfo/qpack
> https://www.sat.ltu.se/mailman/listinfo/arts-users
>
> Regards
>
> Ole Martin
>
>
>
>
> ------------------------------------------------------------------------
> *From:* Facundo Orte [[email protected]
> <mailto:[email protected]>
> <mailto:[email protected]
> <mailto:[email protected]>>]
> *Sent:* Tuesday, November 18, 2014 12:44 PM
> *To:* Patrick Eriksson
> *Cc:* Ole Martin Christensen
> *Subject:* Re: Question about ARTS
>
> Dear Patrick Eriksson,
> thanks for your reply.
> The MWR is installed in Río Gallegos city (Latitud: -51° 36'
> 02,03",Longitud: -69° 19' 09.96") since 2011. The name of the
> observatory is "Observatorio Atmosferico de la Patagonia
> Austral"
> which depends to Lidar Division (CEILAP). You can see the
> site in
> this link http://www.division-lidar.com.ar/sitios_rg.html.
> It is
> quite near to Ushuaia.
> The MWR is working at 110.83GHz. For calculate the opacity
> from the
> MWR we can use, for example, the method described by Zafra
> et al.
> (Zafra, R. L., Parrish, A., Solomon, P. M and Barrett, J. W., A
> Quasi-continuous record of atmospheric opacity at λ=1.1 mm
> over 34
> days at Mauna Kea Observatory, International Journal of
> infrared and
> Millimeter Waves, Vol. 4, No 5, 1983.). Comparisons between the
> opacity measured and obtained from radiosonde profiles
> presents good
> agreement.
> If I may to introduce the measured opacity (by MWR) as
> input of ARTS
> maybe it could be good. My question is:where can I input the
> measured opacity in ARTS?
> Thanks a lot
> Best Regards
> Facundo
>
>
> 2014-11-17 15:53 GMT-03:00 Patrick Eriksson
> <[email protected]
> <mailto:[email protected]>
> <mailto:[email protected]
> <mailto:[email protected]>>>:
>
> Dear Facundo Orte,
>
> Nice to hear that you have started to use Qpack.
>
> Getting curious, where exactly is the radiometer
> placed? Did
> some travelling around Latin America in the 90-ies.
> Passed e.g.
> Uschaia. What frequency is the radiometer using?
>
> Don't understand your question exactly. How do you
> observe an
> opacity with the radiometer? I don't know how that could be
> done. Measured brightness temperatures can be converted
> to an
> opacity, but then it is better to use the original
> Tb-data. Or
> is the opacity determined by some other instrument. If you
> describe this closer, we will try to help you.
>
> Regards,
>
> Patrick
>
>
>
> On 2014-11-17 19:05, Facundo Orte wrote:
>
> Dear Patrick Eriksson,
> My name is Facundo Orte and I am a PhD student of
> the Lidar
> Division of
> CEILAP (Laser Research Center) from Argentina
> (division-lidar.com.ar
> <http://division-lidar.com.ar> <http://division-lidar.com.ar>
> <http://division-lidar.com.ar>__).
>
> I am writing you because in our laboratory there is a
> Millimiter Wave
> Radiometer (MWR) instaled in South Patagonia, near
> to the
> spring ozone
> hole, and we retrieve ozone profiles with it. To
> analyze the
> signal we
> are trying to use the ARTS model that you and your team
> developed. I am
> using MATLAB to introduce inputs changing
> Q.DEFINITION.m
> function and I
> retrieve some profiles but there are quite close to "a
> priori" ozone
> profile (I am using MLS climatology as a priori O3
> profile).
> I think
> that it is because I do not have well caracterized the
> atmosphere and I
> am trying to do that. For example, at this moment,
> I do not
> know how to
> introduce the opacity measured for the MWR
> instrument from
> MATLAB as
> input and I think that it is an important parameter to
> introduce.
> Could you help me with it? Do you know how I can to
> introduce the
> opacity from MATLAB?
> I will very appreciate if you can help me with it.
> Thank you in advance
> Best regards
> Facundo Orte
>
>
>
>
>
>
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