Oxford MIPAS meeting#111
06 February 07

Present

Oxford: Anu Dudhia, Michael Holmes, Jane Hurley, Luis Millan-Valle, Chiara Piccolo, Joanne Walker, Claire Waymark

Instrument Status [Prev] [Next]

Currently operating normally.

22-23 Jan: Envisat Orbital Control manoeuvre was performed, which probably meant the loss of some or all of the 3 days of Nominal mode measurements that MIPAS was scheduled to perform from 23-26 Jan.

31 Jan: Problem with Envisat transmission via Artemis, may have caused interruption in MIPAS 3-days of Nominal Mode measurements scheduled for 30Jan-2Feb.

MIPAS should be about to start 3 days of continuous UTLS1 measurements (6-9 Feb).

Mission Planning Document for 2007 [XLS] [HTML].
Currently defined measurement modes
Envisat Web-Site

L1B Data (JH) [Prev] [Next]

Slight reworking of L1B coverage maps to include additional modes

[L1B Data Coverage]

Precision Validation (CP) [Prev] [Next]

Paper now on the ACPD web-site

Comments from 3 referees received, now working on responses.
All have noticed that there is an incorrect figure in the paper! The correct Fig. 3 is this: [EPS] [PDF]

O3 Isotopes (CP) [Prev] [Next]

Reselecting microwindows for O3 isotopic retrievals

Currently looking at reducing NESR by factor 10 (simulate effect of a Kalman filter) plus remove all spectroscopic database and instrument-effects from the selection (GAIN,SHIFT,SPREAD) since these tend to dominate the error budget (will put them in retrospectively once selection is complete).

HIRDLS Comparisons (CW) [Prev] [Next]

Recently attended HIRDLS team meeting in Colorado

New version of HIRDLS L2 data will be produced: v2.02.07
HIRDLS still only has confidence in T, O3 and HNO3 products.

CO Retrieval (JW) [Prev] [Next]

Retrieving (CO + Vibrational temperature) jointly using RFM plus external IDL code.

Verified that retrieval performs same as MORSE for LTE retrieval for simulated data (MORSE currently only capable of LTE retrieval)
Tried out joint retrieval with 'real' L1B data but very unstable.
Next: revert to trying LTE retrieval with real data, using MORSE for comparison

Cloud Parameters (JH) [Prev] [Next]

Looking to improve upon the current MIPAS pair of microwindows used for cloud detection.

First step is to see if there is any relationship between the current Cloud Index and Cloud Effective Fraction (CEF), defined as the proportion of the FOV filled by cloud multiplied by the absorption of the cloud
Generated a number of simulated spectra for single altitude (9km) corresponding to different atmospheric conditions, cloud top heights and cloud extinctions (ie for which CEF is known).
[Plot] showing log(log(CI)) v CEF seems to produce a reasonably straight line, but why log(log) ?
Red line on plot corresponds to current detection threshold of 1.8, suggesting that the current scheme is flags clouds for CEF > 0.4, at least at 9km.
A 'better' CI would be defined as one for which a measured CI translates more accurately to a particular CEF, eg for which the vertical scatter was smaller and/or slope steeper (but log(log) relationship may not be applicable for other pairs of microwindows)

Mesospheric Temperatures (LMV) [Prev] [Next]

Attempting a linear temperature retrieval from mesospheric spectra. Using mid-latitude day-time conditions for a reference spectrum (=initial guess) and jacobians.

Included masks for lines affected by non-LTE but still get strange retrievals (too hot at 52km) even at mid-latitudes where the linearity should be more valid

Aircraft Emission Mode (AD) [Prev] [Next]

Run MORSE to retrieve orbits of nominal and AE mode data

[Presentation] (.ppt) from MIPAS ST5
[Map] of orbit 25235 (27Dec06), blue is nighttime, red is daytime. Note shift to sideways (AE mode) viewing over W.Europe between scans#10-30
[Curtain Plot] of temperature retrieval on pressure surfaces, showing good continuity between end of AE mode and resumption of Nominal mode over N.Atlantic (similar latitudes)
[Curtain Plot] of temperature on engineering altitude surfaces, showing ~5km discontinuity at transition.

From this it is concluded that there is still a 5km offset in the actual altitudes compared to the engineering altitudes from rearward to sideways viewing, as in the May 05 data.

Aircraft Emissions (MH) [Prev] [Next]

Trying to detect aircraft emission signatures in MIPAS spectra.

Decided to work with AE Mode measurements (Dec06)
NO2 looks most likely candidate, in terms of a relative enhancement (+10s of %) but haven't yet considered absolute value for a limb path
Unclear from the literature whether increased NO2 should result in decreased O3 (as in stratosphere) or decreased O3 (as in troposphere).
Requested model data from CAS (Cambridge) for more info on expected perturbations

MIPAS Science Team Meeting#5 (AD) [Prev]

Held in Granada, 25/26 Jan 2007

Minutes [MSWord] [PDF] from Claus Zehner (ESRIN).

ACPD Papers [Prev] [Next]

Papers selected from the ACPD website for discussion

"HDO measurements with MIPAS": J. Steinwagner et al. (published 19.01.2007, open until 16.03.2007); Introduced by AD
" Three years of global carbon monoxide from SCIAMACHY: comparison with MOPITT and first results related to the detection of enhanced CO over cities": M. Buchwitz et all. (published 11.1.07, open until 08.03.2007); Comments being collected by JW.
" A twenty-year study on natural and manmade global interannual fluctuations of cirrus cloud cover": K. Eleftheratos et al. (published 05.01.07, open until 02.03.07); Comments being collected by JH
" Solar cycle variations of stratospheric ozone and temperature in simulations of a coupled chemistry-climate model ": by J. Austin et al. (published 27.11.06, now closed); Comments were collected by CW but she just missed the deadline for submitting them to the discussion.

There are other MIPAS-related papers currently open (which may be adopted for group discussion in future meetings)

" Global peroxyacetyl nitrate (PAN) retrieval in the upper troposphere from limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)": N. Glatthor et al. (published 29.01.2007, open until 26.03.2007)
" Precision validation of MIPAS-Envisat products": C. Piccolo & A. Dudhia (published 18.01.2007, open until 15.03.2007) - OK, we're not going to discuss this one!
" Technical Note: Regularization performances with the error consistency method in the case of retrieved atmospheric profiles": S. Ceccherini et al. (published 18.12.06, open until 12.02.07)
" Characterization of MIPAS elevation pointing": M. Kiefer et al. (published 13.12.06, open until 07.02.07)

Oxford MIPAS meeting#111 06 February 07

Oxford MIPAS meeting#111
06 February 07