Earthdata Forum

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.

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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/