1 Water vapour continuum in windows: Processing the recent MSF
RAL measurements Igor Ptashnik Dept. of Meteorology, University of
Reading 10 February 2011 Cambridge Slide 2 2 Processing MSF RAL
pure H 2 O measurements Retrieved experimental self-continuum in
windows is an order of magnitude stronger than MTCKD in model. For
2500 cm -1 and 4600 cm -1 windows the disagreement increases with
temperature, reaching a factor 25 at 470 K. Ptashnik, McPheat,
Shine, Smith, Williams, submitted to J. Geophys. Res. Slide 3 3
Temperature dependence. Simple analysis. Slide 4 4 Slide 5 5
Saturated P H2O (mb) T (K)P H2O (mb) 3530010(F), 20(F) 41635010(F),
50(F), 300 F 100037550(F), 400, 600 F,750 2500400 600 F,1000, 1500
F,2000 5700430 600 F,1000, 1500,2000, 3000, 4000 14000470
1000,2000, 3000, 4000, 5000 Resolution (cm -1 ): N of scans:
0.050.1 0.2 : 0.3 1000 500 MSF RAL measurements (R. McPheat, K.
Smith, G. Willaims) Foreign H2O measurements (foreign-continuum) 1)
empty cell 2) Air (5 atm) - background 3) H 2 O + Air (total 5 atm)
- sample 4) Air (5 atm) - background 5) empty cell Slide 6 6 MSF
RAL measurements: H 2 O - Air Foreign H2O-Air continuum Is derived
as: (RAL UCL lines ) RAL self-continuum CIA N 2 -N 2 and O 2 -O 2
contribution is subtracted by using Air as a background. Slide 7 7
Foreign continuum: H 2 O Air Foreign H2O-Air continuum in near-IR
windows is also an order of magnitude stronger than in MT_CKD-2.5
model! 350 K 372 K 400 K Air Slide 8 8 Water vapour self-continuum
and water dimers: 1. Analysisof recent work IV Ptashnik, KP Shine,
AA Vigasin, JQSRT, in press Slide 9 9 Water vapour self-continuum
and water dimers: 2...... in preparation...
