[ncl-talk] Question about the built-in function trop_wmo

[王娜]

Hi Dennis,




The abnormal values are still existent ( at different grid points) when a single year month data are used. I have also tried the daily resolution, but it didn't work.

I could only adjust the calculation order. First calculate the monthly mean tropopause pressure , then set the outliers to missing_value. 

Finally temporal average to yield the climatological mean tropopause pressure without these missing_value.




Thanks for your reply.




Best

Wang Na













-----原始邮件-----
发件人:"Dennis Shea" <shea at ucar.edu>
发送时间:2017-09-21 08:25:07 (星期四)
收件人: "王娜" <wangna at mail.iap.ac.cn>
抄送: "ncl-talk at ucar.edu" <ncl-talk at ucar.edu>
主题: Re: [ncl-talk] Question about the built-in function trop_wmo


Source variable:  air(time, level, lat, lon)


Then you do

tf   = addfile(dir + "air.mon.mean.nc", "r")
temp = tf->air
temp = temp + 273.15                               ; units conversion (from degC to K)
ta   = dim_avg_n_Wrap(temp, 0)               ; compute climatology

===

Thie climatology is calculated over all months and year yielding


  ta(level,lat,lon)

===


I have *not* run the script or looked at the source  fortran code for the 'trop_wmo' function.


The temporal averaging over all years and months has smeared out the vertical profiles at each grid point.

I *speculate* that the 'vertical change criterion' used by the function to detect the tropopause has been 'smoothed away'.


You might try a single year month for testing. Keep in mind that the monthly averages are also averages.




Good luck





On Wed, Sep 20, 2017 at 8:15 AM, 王娜 <wangna at mail.iap.ac.cn> wrote:


Hi all, 




I am trying to calculate the tropopause pressure with the built-in function trop_wmo, but got some abnormal values (equal to 85 hPa or -999 hPa) when using the monthly temperature from NCEP/NCAR reanalysis 1 (17 levels between 1000 hPa and 10 hPa).  It seems like that this problem is related to the vertical resolution of the input temperature. If I use the ERA-interim reanalysis data (32 levels between 1000 hPa and 10 hPa), the abnormal values are non-existent.  Does the function trop_wmo not apply to the renanlysis data with coarse resolution? Any help on how to fix this problem? 

Attached are my ncl script and input data.




Thanks

Wang Na




从mail.iap.ac.cn发来的超大附件
air.mon.mean.nc (305MB, 2017年10月05日 22:15 到期)
查看下载信息 

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