Re: calipso (hdf_eos) contour plot

Hi Lin

The real issue is associating the Latitude/Longitude arrays which
are dimensioned (4001,3) with variables that are dimensioned (4001,8).
Also, there is a very high percentage of missing data [-9999.]

The Calypso hdf file is pretty minimalistic. The whole idea
about self-describing file formats [netCDF, hdf] is that
all the information is contained within the file. This Calypso file
fails that!
There must be some external documentation
that explains this rather confusing dimensioning. I *speculate* that
the (4001,3) possibly refer to three different views or swaths from the
satellite.
You will have to find that information yourself.

You say: "I want to get the contour plot
within lat(15N,45N) and lon(170E, 180E) of pacific ocean area."

This is a satellite *swath* [maybe multiple swaths?] that passes over
the Pacific.
There are only point values below. Geting a nice grid that has, as input,
some point values from a *narrow* swath is full of problems.

In a separate email, I will send a script that you should run.
The NCL function "triple2grid" is used but you will have to experiment.

Good luck
D

Lin Su wrote:
> Hi Mary,
>
> Thanks for your effort:) You are absolutely right: how to connect the
> Feature_Optical_Depth_532 variable(FOD532) to the lat&lon is the problem.
> The only information that I know which associate the lat&lon with FOD532
> variable is that the 4001 profiles in FOD532 are averaged over a 5 km range in
> the horizontal. Do you think I should use some index/function to
> regrid/interpolate them to get the contour plot?
>
> Thanks a lot,
> -Lin
> ---
> Lin Su
> http://atoc.colorado.edu/~sul/
>
> ---- Original message ----
>
>> Date: Wed, 23 Jul 2008 06:43:55 -0600
>> From: Mary Haley <haley_at_ucar.edu>
>> Subject: Re: calipso (hdf_eos) contour plot
>> To: Lin Su <Lin.Su_at_colorado.edu>
>> Cc: Dennis Shea <shea_at_ucar.edu>,ncl forum <ncl-talk_at_ucar.edu>
>>
>> Hi Lin Su,
>>
>> You have Latitude and Longitude arrays on the file, but they are
>> dimensioned
>> 4001 x 3, whereas Feature_Optical_Depth_532 is dimensioned 4001 x 8.
>>
>> Is there some way that the Latitude/Longitude arrays are associated
>> with your
>> Feature_Optical_Depth_532 variable?
>>
>> --Mary
>>
>> On Jul 22, 2008, at 7:01 PM, Lin Su wrote:
>>
>>
>>> Hi Dennis,
>>>
>>> You are right:) I got the same results. However, I want to get the
>>> contour plot
>>> within lat(15N,45N) and lon(170E, 180E) of pacific ocean area. Do you
>>> have any
>>> idea to how to do it? BTW, variable Feature_Optical_Depth_532 has
>>> dimensional
>>> (4001,8), which means profiles number and layers. My question is how to
>>> contact this variable with lat&lon, then get the contour plot within
>>> above
>>> domain?
>>>
>>> Thanks for your great help and valuable time!
>>> -Lin
>>> ---
>>> Lin Su
>>> http://atoc.colorado.edu/~sul/
>>>
>>> ---- Original message ----
>>>
>>>> Date: Tue, 22 Jul 2008 18:05:45 -0600
>>>> From: Dennis Shea <shea_at_ucar.edu>
>>>> Subject: Re: calipso (hdf_eos) contour plot
>>>> To: Lin Su <Lin.Su_at_colorado.edu>
>>>> Cc: ncl forum <ncl-talk_at_ucar.edu>
>>>>
>>>> Hi Lin
>>>>
>>>> %> ncl_filedump -v Feature_Optical_Depth_532
>>>> CAL_LID_L2_05kmALay-Prov-V2-01.2007-05-02T01-15-05ZD.hdf |
>>>>
> less
>
>>>> Yields ...
>>>>
>>>> [SNIP]
>>>> float Feature_Optical_Depth_532 ( fakeDim113, fakeDim114 )
>>>> units : N/A
>>>> format : Float_32
>>>> valid_range : 0.0...5.0
>>>> hdf_name : Feature_Optical_Depth_532
>>>> [SNIP]
>>>> Variables:
>>>>
>>>> Feature_Optical_Depth_532:
>>>>
>>>> -9999. -9999. -9999. -9999. -9999. -9999.
>>>> -9999. -9999. 0.3222E-01 -9999. -9999. -9999.
>>>> -9999. -9999. -9999. -9999. -9999. -9999.
>>>> [SNIP]
>>>>
>>>> NCL reads the variable just fine.
>>>>
>>>> It looks like the _FillValue is -9999.
>>>>
>>>> f = addfile (....)
>>>> x = f->Feature_Optical_Depth_532
>>>> x@_FillValue = -9999.
>>>>
>>>> Good luck
>>>>
>>>> Lin Su wrote:
>>>>
>>>>> Hi Dennis,
>>>>>
>>>>> Sure:)
>>>>> I just put the data named "CAL_LID_L2_05kmALay-Prov-V2-01.2007-
>>>>>
> 05-
>
>>>>> 02T01-15-05ZD.hdf" in NCAR's incoming directory.
>>>>>
>>>>>
>>>>>
>>>>>>>> Lin Su wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> Dear NCL users,
>>>>>>>>> does anyone know how to get the calipso contour plot for
>>>>>>>>> Feature_Optical_depth_532 using ncl scripts? If you'd like to
>>>>>>>>> help me
>>>>>>>>>
>>> out,
>>>
>>>>
>>> _______________________________________________
>>> ncl-talk mailing list
>>> ncl-talk_at_ucar.edu
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>

-- 
======================================================
Dennis J. Shea                  tel: 303-497-1361    |
P.O. Box 3000                   fax: 303-497-1333    |
Climate Analysis Section                             |
Climate & Global Dynamics Div.                       |
National Center for Atmospheric Research             |
Boulder, CO  80307                                   |
USA                        email: shea 'at' ucar.edu |
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