Calculating tropopause height with function trop_wmo

Greetings NCL users,

I have been using the trop_wmo function to calculate tropopause heights, and have noticed that for a few of the soundings (5% at most), the height calculated by the function does not seem reasonable. One example may be found here: http://www.atmos.albany.edu/student/pduran/ncl_talk/060709_1200.png

On the left is a standard SkewT and on the right is a plot of T vs. logP. The orange horizontal line indicates the tropopause level calculated by trop_wmo, and the red line indicates the tropopause calculated by a script that I wrote using the same WMO definition included in the trop_wmo documentation. I do not understand why trop_wmo places the tropopause within the approximately isothermal layer just below 100 mb...

Though the trop_wmo calculation and my calculation agree very closely for the vast majority of cases, the few cases where they do not agree lead me to question how the trop_wmo function performs the tropopause calculation. Does anybody know how precisely trop_wmo calculates the tropopause? Your help is greatly appreciated.

If you're interested, here is the sounding data file and script that I used:

Sounding data: http://www.atmos.albany.edu/student/pduran/ncl_talk/03937-0607091200-RAWIN_6S-BOGFIX-T8C_KM-100m-loc.edit_QC_QC2

NCL script: http://www.atmos.albany.edu/student/pduran/ncl_talk/tropopause_height.ncl.

Thanks very much,

Patrick Duran

_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk
Received on Mon Feb 10 07:47:53 2014