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Saturday 23.05.09

  • Weather briefing 0530 UTC: in case of bad forecast, Session_ID 00 today will be cancelled.
  • Measurements today  
    • 23.05.09  0700 UTC to 1000 UTC  Session_ID 00  daytime
    • 23.05.09  1930 UTC to 2030 UTC  Session_ID 01 nighttime
      (longer if necessary)
  • Weather briefing 1300 UTC  => decision whether to do a Session_ID 01 2000 to 2300 UTC,
    and about situation on Sunday.
  • Message from Albert, 11:57 UTC:

Hi Volker,

I just looked into the AERONET data for Leipzig:

Optical depth (500nm): 0.16-0.18 (0700 UTC)

Angstroem exponent (440-870nm): 1.65-1.7 AE is very high.

The lofted layers seem to be smoke, or is that all northern German urban haze in the PBL?

What does the depolarization ratio tells us....?



Answer from Volker:
I averaged several cloud-free profiles between 06:50 and 09:08 UTC.
In the BL the aersol depol. is very low around 2%, the aerosol OD about 0.08 @532 nm.
The exco in the layer from BLT to 4.5 km is about 0.004/km with a max. of 0.007/km at 4, 6.5 and 8 km a.g.,
with Klett assuming a LR of 80sr at 532 nm. With that the aerosol optical thickness between 0.3 and 11 km
a.g. is only about 0.1 at 532 nm. Thus it is difficult to determine the aerosol depolarisation in the
lofted layers. For the aerosol cloud maxima at 4, 6.5 and 8 km a.g. I get an aerosol depol.
of about about 0.25 to 0.3. (all figures quality level 0.5)

=> Question to everybody: Who can do it more accurate? Please try!