L3 CALIPSO AOD Mean Values vs AOD by aerosol type

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ses2271
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L3 CALIPSO AOD Mean Values vs AOD by aerosol type

by ses2271 » Tue Jun 15, 2021 6:47 pm America/New_York

Hi there,

On the level 3 tropospheric aerosol profile data users page (https://www-calipso.larc.nasa.gov/resou ... 0_desc.php) it indicates that the data product contains the variable AOD_Mean [Dust, Elevated Smoke, Polluted Dust]. The bracketed list at first seemed to imply that the variable "AOD_Mean" only includes optical depth from the three types of aerosols listed.

However, in the downloaded files there are additional variables, including "AOD_Mean_Dust," "AOD_Mean_Polluted_Dust," and "AOD_Mean_Elevated_Smoke," that are not listed in the user guide. I assumed that these variables show the optical depth attributable to each of the three aerosol types, which brings me to my first question:

1) Is this the correct interpretation of these three variables?

When summing the three AOD_Mean_type variables I saw that the summation was less than the AOD_Mean variable, suggesting that AOD_Mean also includes optical depth from aerosol types not in the brackets.

2) Could you confirm that that is also the case (and possibly explain the meaning of the bracketed list, if so)?

Thanks in advance for your help!

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ASDC - David W.
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Re: L3 CALIPSO AOD Mean Values vs AOD by aerosol type

by ASDC - David W. » Wed Jun 16, 2021 12:01 pm America/New_York

Greetings Ses2271,

Thank you for contacting us with an interest in CALIPSO Lidar Level 3 Tropospheric Aerosol Profile Monthly Product Version 4.20 data.

The assumption you make in Question #1 is correct.

Your Question #2 has been sent to the CALIPSO Team for further explanation. When they provide me with an answer, I will post it here.

Additionally, if you have questions about the data or how to use it, please feel free to ask experts your questions on the Earthdata Forum.

Sincerely,

David :)

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Re: L3 CALIPSO AOD Mean Values vs AOD by aerosol type

by ASDC - David W. » Thu Jun 17, 2021 4:42 pm America/New_York

Hello again Ses2271,

The CALIPSO Team has provided me with a reply to your Question #2.

The CALIPSO AOD_Mean product implies all species of aerosols, not just specific types (see below).

Aerosol Optical Properties: All Species [AOD_Mean]
Aerosol Optical Properties: Dust Only [AOD_Mean_Dust]
Aerosol Optical Properties: Elevated Smoke Only [AOD_Mean_Elevated_Smoke]
Aerosol Optical Properties: Polluted Dust Only [AOD_Mean_Polluted_Dust]

Therefore, AOD_Mean will include everything, not just Dust, Elevated Smoke, and Polluted Dust. So one cannot add the three together and get All Species.

I hope this answers your question.

Sincerely,

David :)

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ses2271
Posts: 6
Joined: Thu May 20, 2021 9:56 pm America/New_York

Re: L3 CALIPSO AOD Mean Values vs AOD by aerosol type

by ses2271 » Tue Jun 29, 2021 4:22 pm America/New_York

Hi David,

Yes, this is very helpful--thank you!

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