Selecting microwindows for new nominal mode operations
which employ floating altitude grid (lowest altitude 3-9km from pole-equator)
and 1.5km spacing at lower altitudes
- Microwindow selection, LUTs and irregular grids now complete for
all species (HNO3 was last to be finished).
Day/Night Differences (VP)
Plots show monthly mean of day-night differences as function of sweep
index for entire MIPAS OFL dataset Jul03-Mar04
- [ALT] (ie altitudes reported in L1B data)
at low latitudes show some systematic stretch of the order of a few hundred
metres in the nighttime tangent point grid compared to daytime. Given that
the earth oblatness effect should be uniform with latitude, what causes this?
- [PRE] the retrieved pressure at low latitude
shows features consistent with the day/night stretch in tangent points (ie
the 'stretch' is real). At high latitudes there seem to be more systematic
day/night shifts in the entire pressure profile, particularly around solstices.
For 60-90deg latitude bands (marked '75N' and '75S')
this may simply be due to the terminator causing the average
latitude of the 'day' and 'night' bands to change with season but this does
not so obviously explain the features in the 20-60deg bands '45N', '45S'.
- [TEM] shows high latitude features which may
be associated with the pressure differences. At low latitudes there seems to
be some evidence of the expected diurnal tide (vertical wavelength ~25km).
- [CH4] also shows features which may be related
to pressure variation.
- After correcting for the day/night pointing/pressure variation,
the retrieved
[TEM] and [CH4] fields still
show similar features but reduced by 50% (note that the range of the colour
scale is reduced by a factor 2).
It is possible that this is due to
interpolating linearly rather than logarithmically when performing the
pressure correction.
RAL Work (AW)
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Using MORSE to retrieve orbit of S6 special mode data.
- Currently have problems with pT retrieval: tangent pressures often
do not vary monotonically with sweep altitude.
