Oxford MIPAS meeting#38
02 Sep 03

Present

Oxford: Alastair Burgess, Anu Dudhia, Chiara Piccolo, Clive Rodgers (plus written contributions from Vivienne Payne)
RAL: Martin Juckes

Instrument Status [Prev] [Next] (Some details on the Envisat Web-Site)

Nothing to report - apparently functioning normally

L1 Data [Prev] [Next]

MIPAS monthly report for July shows that ILS width is significantly reduced if correct parameters are used (see last meeting). Originally thought that correction was included in v3.3 of MIPAS PS2 auxiliary data (from late July onwards), but subsequently informed (9 Sep) that the patch has not yet been implemented.

L2 Data [Prev] [Next]

In /home/crun/eodg/mipas/L2/ [Plots of profile locations]

Data received up until 1st September, plotted up until 31st August.
Some L2 data has now been retrieved for every day since 5th June, 73 days of continous operation.
Software version 4.59 in use since 23 Jul 2003.
Problem with more reported NO2 profiles than pT in L2 data returned in July and persists - possibly a result of v4.59 replacing 4.57 in which the problem appeared to be fixed? (Meeting#33). See problem report from Chiara Piccolo.
OM Stats for August suggest that cloud detection is behaving as expected

Data Assimilation [Prev] [Next]

MIPAS monthly report for July notes that ECMWF CY26R3 model now assimilates AIRS radiances and MIPAS ozone, although AIRS ozone information seems incompatible with MIPAS. Also significant changes in upper stratosphere/lower mesosphere model temperatures.

(MJ) Compared HALOE and MIPAS CH4 on 850K isentrope (~10mb) - MIPAS approximately 10% higher than HALOE.

Additional Species (AD) [Prev] [Next]

Microwindow selection for species not previously considered in detail (see last meeting). Results now completed. Extracts from Full Report (37 pages):

CO (2 pages) [Next]
NO (2 pages) [Next]
CO2(1 page) [Next]

ASSFTS-11 Workshop (8-10 Oct) [Prev] [Next]

Submitted abstracts:

AB: SF6
VP: CH4 and H2O
AD: REC analysis
CP: Oxford (OPTIMO) retrievals during Antarctic Split Vortex (Sep/Oct'02)

Time Series (VP) [Next]

Plots of time series of MIPAS monthly mean CH4, H2O and (2CH4+H2O) for six latitude bands Jul'02-Jul'03

Water vapour plots show ascent of dry air in the tropics, possibly in keeping with the tropical tape recorder effect, but pulse seems rather short.
Methane fields show air descending into the polar vortex.
By visual inspection, areas of high water vapour are generally correlated with areas of low methane, as would be expected.
There are some unexpectedly high water vapour values for 75N around October/November 2002, but there is also an area of particularly low methane slightly higher up and earlier in time.
H2O+2CH4 values are, in general, reasonably uniform and in the region of 7ppmv. Values for July 2002 are anomalously high, but I suppose we are not too worried about that now, and there are strange low values in August 2002 for all latitude bands. Not sure why this is...... It looks like it comes from the water vapour.

Monthly Mean Data [Prev] [Next]

MIPAS Monthly Mean data now available for Aug03 (Jul03 discussed in Meeting 36)

August data is mostly processor v4.59 (July was v4.57)

Altitude (AD)
- Reported altitudes are generally of the order of 1km higher than the nominal altitudes for low/high latitudes (especially at low altitude) - expect all latitudes to agree with nominal at some altitude (~21km).
- Some symmetry with latitude
- No significant change from previous month
Pressure (AD)
- Pressures at each tangent point reduced by ~10% (at lower altitudes) compared with previous month.
- Since reported tangent altitudes unchanged this may be as a result of change in ILS?
- Agreement with climatology improved, but still ~10% higher than expected for reported tangent altitudes.
Temperature (AD)
- No significant changes from 20S-65N, changes of the order of 10K at other latitudes probably consistent with atmospheric changes.
- Main departures from climatology occur at 40km, 65S-90S is 30K warmer and 65N-90N is 30K colder.
- Polar summer mesosphere (65N-90N) is 20K warmer than climatology (actually very similar to 65S-90S profile above 36km).
CH4 (VP)
- No significant change from previous month
- The mean methane profile shows rather low values at 15km for 20S-20N compared to what would be expected from the climatology, but this is consistent with the mean profiles from previous months (November 2002 onwards).
- 12km values continue to be unrealistically high, especially low latitudes (introduction of cloud-detection in v4.59 was expected to reduce this).
H2O (VP)
- Water vapour values at 18km for the southern polar profile shows a strange low value. Again, this has been seen in previous months (June/July), but July showed bigger variations that June, and August shows bigger variations than July.
2CH4+H2O (VP)
- H2O+2CH4 values look reasonably sensible, being in the region of around 7.5ppmv throughout the stratosphere. (Except for the 75S case which shows strange behaviour because of the strange water vapour profiles)
HNO3 (AB)
- EQU-20N much higher than climatology at 12km otherwise the equatorial values are consistent (20S-20N) and lower than climatology.
- 65S-90S higher than climatology.
- Mid-latitudes as expected and of similar magnitude and shape.
- 12km for EQU-20N is much higher than expected, despite cloud flagging. Other latitudes are better.
- This month/last month values are close together, indicating stability, except for 65S-90SS.
- Around 20km both 65S-90S and 20S-65SS are much less than climatology. The 20S-65S is unexpected, but may be due to an incorrect climatology.
- Day/night values similar for all Latitude bands.
N2O (AB)
- 60S-90S much lower than climatology.
- Mid latitudes as expected, 20S-20N higher, but of similar magnitude and shape.
- 12km for EQU-20N is much higher than expected, despite cloud flagging. Other latitudes are better.
- This month/last month values are close together, indicating stability.
- Day/night values very similar for all.
NO2 (CP)
- 60S-90S (polar night) values still high with peak at 37km but consistent with night-time profile
- Day-time values still lower than standard mid-lat daytime profile by 50%, but similar shape
- 60N-90N night-time lower than standard mid-lat nighttime profile (as in July)
O3 (CP)
- 60S-90S still anomalously low below 40km
- "S" shape in differences compared to IG is still present

Generally not much indication of any improvement due to cloud-flagging which should have been introduced with v4.59.

Date: Tue, 2 Sep 2003 12:32:40 +0100 (BST)
From: Chiara Piccolo 
To: EOHelp@esa.int
Cc: Gabriella.Scarpino@esa.int, Rob.Koopman@esa.int,
     Anu Dudhia 
Subject: Re: inconsistency in number of profiles in MIPAS l2 products HD/02
    -2003/1077


In the version 4.59 there is still the inconsistency in the number of 
profiles of PT and NO2 for MIPAS L2 products.
This problem appears in both PDE and PDK files, exmples are:
MIP_NL__2PNPDE20030801_010453_000005672018_00346_07414_1952.N1
MIP_NL__2PNPDK20030801_090414_000005782018_00350_07418_3656.N1
(please find these files in attachment)

In the case of MIP_NL__2PNPDE20030801_010453_000005672018_00346_07414_1952.N1
In the RESIDUALS SPECTRA ADS:
Number of profiles scanned in READ_RESIDUAL:        5
PT	RECORD		NRET  	
	0 	        1
	1 	        5
	2       	5
	3       	5
	4       	1
NO2     RECORD          NRET 
        0               1            
        1               6
        2               6
        3               6
        4               6
NRET = number of retrievals for which mean values  and standard deviotions 
       are computed
Reference: fields 9 and 13 of ADS#6 (Residual spectra, mean values and 
standard deviation data) of PO-RS-ESA-GS-0177.

For the other species it works fine, only NO2 is problematic.

Best regards,
Chiara

On Tue, 10 Jun 2003 Gabriella.Scarpino@esa.int wrote:

> 
> 
> Dear Chiara Piccolo,
> 
> Concerning the issue below, please, be informed that the problem as you reported
> has been fixed in the new IPF version (4.57).
> 
> We hope this information has been of use.
> 
> Regards.
> Gabriella Scarpino
> 
> ----- Forwarded by Rob Koopman/esrin/ESA on 2003/02/17 17:49 -----
> |--------+----------------------->
> |        |          Chiara       |
> |        |          Piccolo      |
> |        |           |        |          ox.ac.uk>    |
> |        |                       |
> |        |          2003/02/17   |
> |        |          12:16        |
> |        |                       |
> |--------+----------------------->
>   >----------------------------------------------------------------------------|
>   |                                                                            |
>   |       To:     Guy Brooker                          |
>   |       cc:     Anu Dudhia , Herbert Nett               |
>   |       , Jean-Claude Debruyn/estec/ESA@ESA, Rob      |
>   |       Koopman/esrin/ESA@ESA                                                |
>   |       Subject:     L2 files                                                |
>   >----------------------------------------------------------------------------|
> 
> 
> 
> 
> 
> 
> Hello Guy,
> I still have problems with MIPAS L2 files.
> It appears that the number of NO2 profiles is greater than the number of
> pT profiles. An example is on 2nd Febrary: 359 pT profiles and 366 NO2
> profiles (coming from the number of pT and species VMR retrievals for
> which mean values and standard deviations are compute, fields 9 and 13 of
> ADS#6 (Residual spectra, mean values and standard deviation data) of
> PO-RS-ESA-GS-0177).
> 
> Looking for example at the file (also attached):
> MIP_NL__2PNPDK20030202_173516_000005672013_00284_04847_4329.N1
> 
> the number of residual records is 3, the number of averaged retrievals for
> pT (and also the other species) for these three records is 6 1 6, but for
> NO2 is 7 7 7. Therefore the total number of pT retrievals seems to be 13
> and 21 for NO2, BUT the number of profiles in the file is only 7 (for
> all species).
> 
> Best Regards,
> Chiara

Oxford MIPAS meeting#38 02 Sep 03

Oxford MIPAS meeting#38
02 Sep 03