CALIPSO IIR L2 Track-Standard V4.51

[ille]

Hi,
I would like to retrieve Stratospheric Aerosols. I see there are profiles in CALIOP LIDAR L3 data, but also in IIR L2 Track v4.51 data. I see in the description of the data that these are (lon,lat) data and there are several quantities to know the height, the values can be up to 30km. I do not understand why I obtain values for "Layer_Top_Height_Upper_Level" ~3km even ~6km, but for "Layer_Bottom_Height_Lower_Level" I obtain -9999.00. It says it depends on scene. I do not understand how the altitude in the data is calculated. I do not understand why the upper level is so low (tropospheric) and there is no bottom level. Since I am searching for stratospheric aerosols I do not know how to search for them. Is something wrong or will they eventually appear in other files (i.e. choosing data z>7km)? I thought there were going to be (time, altitude, lon, lat) data and I could represent aerosols at different altitude layers. Thank you very much.

[ASDC-EDL - mcook]

Dear User,
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Warm Regards

[ASDC-EDL - mcook]

Dear User,
We received a response from the CALIPSO team stating the following:

The IIR L2 Track data is not the appropriate product for looking for stratospheric aerosols.

Without understanding what the user wants I will be general in my response.

We have a Level 3 stratospheric aerosol product
Here is a description of the contents of the data product
https://www-calipso.larc.nasa.gov/resources/calipso_users_guide/data_summaries/l3/lid_l3_stratospheric_apro_v1-00_v01_desc.php

And this journal describes in detail the product and algorithm
https://amt.copernicus.org/articles/12/6173/2019/

Stratospheric aerosol layers are identified in our Level 2 layer products. I recommend using our 5km Aerosol Layer product

Here is a description of the contents of this data product
https://www-calipso.larc.nasa.gov/resources/calipso_users_guide/data_desc/cal_lid_l2_layer_v4-51_desc.php

And as noted on that web page -> The fundamental data product provided by the CALIPSO layer products is the vertical location of cloud and aerosol layer boundaries.

Each identified layer is spatially identified by latitude (degrees), longitude (degrees), top (km) and base (km).
Each layer is also defined by a Feature_Classification_Flag.
https://www-calipso.larc.nasa.gov/resources/calipso_users_guide/data_desc/cal_lid_l2_layer_v4-51_desc.php#feature_classification_flags

And here is who the bit field is decoded, with explicit instructions on how to extract stratospheric aerosol
https://www-calipso.larc.nasa.gov/resources/calipso_users_guide/data_desc/cal_lid_l2_vfm_v4-51_desc.php#feature_classification_flags

And this journal article describes in detail how we subtype each of the stratospheric aerosol layers
https://amt.copernicus.org/articles/16/745/2023/