modeling the change in spectrally resolved outgoing longwave radiation n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Modeling the change in spectrally resolved outgoing longwave radiation PowerPoint Presentation
Download Presentation
Modeling the change in spectrally resolved outgoing longwave radiation

Loading in 2 Seconds...

play fullscreen
1 / 21

Modeling the change in spectrally resolved outgoing longwave radiation - PowerPoint PPT Presentation


  • 107 Views
  • Uploaded on

Modeling the change in spectrally resolved outgoing longwave radiation. Wing-Yee (Marie) Lau Aug 18, 2010. Review. Continued. Modeled AIRS (clear) – modeled IRIS (a little cloud), ozone unchanged, offset applied. Tilted. Questions about convolution code.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Modeling the change in spectrally resolved outgoing longwave radiation' - linnea


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
modeling the change in spectrally resolved outgoing longwave radiation

Modeling the change in spectrally resolved outgoing longwave radiation

Wing-Yee (Marie) Lau

Aug 18, 2010

questions about convolution code
Questions about convolution code
  • The convolution code takes weighted average over a distance of “hw” from the center.

for i=0,lines-1,1 do begin

aindex=where(abs(wn-wn[i]) le hw)

wn_temp=wn(aindex)

rad_temp=rad(aindex)

weight_temp=1.-abs(wn_temp-wn[i])/hw

rad_temp=rad_temp*weight_temp

smooth_rad[i]=total(rad_temp)/total(weight_temp)

endfor

  • For a resolution of 2.8 cm-1, “hw” should be 1.4 cm-1. Was “hw” = 2.8 or 1.4 when convolving the measurement data?
    • I was told to set “hw” = 2.8.
  • The convolution code does not change the number of data points, but the AIRS spectra have a uniform wavenumber step of 1.39052 cm-1. What was done besides convolution?
too large iris gas profiles
Too large IRIS gas profiles
  • All gases are order of magnitude smaller, if in unit of number density per cubic meter
  • If scaled up by a factor of 10, look too large.
  • Check CO2 and methane, of which well accepted values are known for 1970.
iris gas profiles converted to volume mixing ratio
IRIS gas profiles converted to volume mixing ratio
  • Accepted concentration of CO2 in 1970: 325 ppm; Our input: 335 ppm
  • Accepted concentration of methane in 1970: 1.4-1.5 ppm. Our input: 1.68 ppm at ground
  • US standard model atmosphere provides rough estimate at a few altitude levels only, and not for tropics. What was done besides interpolating to 101 levels?
more puzzles of the simulation
More puzzles of the simulation
  • My IRIS and AIRS inputs, in ppmv: http://web.gps.caltech.edu/~mlau/IRIS_AIRS_inputs/
  • Original IRIS profiles from Yibo: http://web.gps.caltech.edu/~mlau/TRP_1_MOD.100
  • Ozone was increased by 8% to make AIRS profile, not physical
  • Methane was increased by 40% to make a -6.5 K brightness temperature difference. The true increase should be ~25%.
  • Does frequency shift contribute to the -8K difference at 1304 cm-1?
simulation using profiles from grigg s paper
Simulation using profiles from Grigg’s paper
  • 16 altitude levels only
  • Source: page 17-19 of http://web.gps.caltech.edu/~mlau/Griggs-07-IRIS-IMG-AIRS.pdf
comments on simulation with profiles from griggs s
Comments on simulation with profiles from Griggs’s
  • Grigg’s 1970 profiles are closer than ours to other available sources. But her 2003 profiles are incorrect.
  • Positive difference in water vapor continuum and shape inverted: they used a much smaller water profile for 2003.
continued1
Continued
  • Fail to simulate the ozone signal: no significant difference in stratospheric temperature and ozone concentration in their 1970 and 2003 profiles.
  • Too few levels at the stratosphere, where ozone signal is sensitive to.
decision
Decision?
  • Set “hw” to 1.4 or 2.8 for convolution?
  • Recalculate all profiles from US standard model of atmosphere, or use Griggs’s 1970 profiles and interpolate to more levels?
  • Keep ozone+8% and methane +40%?
update on searching for inversion
Update on searching for inversion
  • Redoing the search for spectra with ozone band inversion, with the same search method for both AIRS and IRIS
  • Finished searching among IRIS and uploaded to http://web.gps.caltech.edu/~mlau/iris_spec_updated/.
  • Sample plots and statistics:
continued4
Continued
  • Checked every 1 in 10 among AIRS (Apr-Dec 2007, Apr-Dec 2008) for ozone band inversion.
  • Uploaded to http://web.gps.caltech.edu/~mlau/airs_spec/.
  • Sample plots and statistics:
continued5
Continued
  • When searching for CO2 inversion, require the whole CO2 band centered at 670 cm-1 to be inverted, or just the Q branch at 720 cm-1?
slide21

Thank you! I really want to, and I will, finish the exciting jobs at hand, though I’m leaving tomorrow.