Cutting Through the Noise to Find a Rhythm: Displaying CALIPSO Data

Category: Assessing Air Quality & Water Resources
Project Team: CALIPSO Cross-Cutting
Team Location: NASA Langley Research Center – Hampton, Virginia

An overlay of a CALIPSO curtain data file in Google Earth, which is used in identifying regions of aerosols from within VOCAL. Image Credit: CALIPSO Cross-Cutting Team

An overlay of a CALIPSO curtain data file in Google Earth, which is used in identifying regions of aerosols from within VOCAL. Image Credit: CALIPSO Cross-Cutting Team

Kathleen Moore
Ahmad Aburizaiza
Andrea Martinez
Adama Ba
Joseph Driscoll

Grant Mercer (University of Nevada, Las Vegas)
Dr. Kenton Ross (NASA Langley Research Center)

Past/Other Contributors:
Emily Gotschalk (Center Lead)
Tyler Rhodes (Center Lead)
Grant Mercer
Nathan Qian
Ashna Aggarwal
Jordan Vaa


The relationship that exists between cloud nuclei and aerosols plays a vital role in Earth’s climate system. For the purposes of detection, the Cloud-Aerosol Light Detection and Ranging (LiDAR) and Infrared Pathfinder Satellite Observations (CALIPSO) satellite offers scientists the ability to better understand the relationship between clouds, aerosols, and climate by measuring the backscatter created by embedded atmospheric aerosols. The standard visualizer for CALIPSO satellite data is limited in its extensibility by the proprietary programming language in which it is written. Hence, development of a new, enhanced visualizer, Visualization of CALIPSO (VOCAL), has been in development by NASA DEVELOP teams since spring 2015. Written in Python, VOCAL displays CALIPSO curtain Hierarchical Data Format (HDF) files for both backscattered and depolarized Level 1, Version 3 data. In addition, the user can draw polygons overlaying the displayed data, to mark potential regions-of-interest. Subsequently, these regions can be tagged with attributes and notes. VOCAL can export to a database or to JavaScript Object Notation (JSON) files any shapes that the user may want to save. This term, the CALIPSO Cross-Cutting team added support for the newest CALIPSO data product (Version 4), alternative viewing options for the data in VOCAL, as well as a suite of use-cases for the software.

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Momadou 21-08-2016, 07:24

Dear team member,
this video is good and very useful!

Daryl Ann Winstead (Mekong River Basin Agriculture) 18-08-2016, 15:30

Great project! Did the team run into any limitations with the software? Thanks in advance for your response!

Katie Moore 19-08-2016, 10:48

Hi Daryl Ann! Thanks very much. We are definitely limited in run-time by the sizes of these HDF files and by the libraries we use to visualize them. Right now, we utilize a 32-bit library for visualizing the data, which leaves half of a 64-bit machine’s bandwidth unused. We need to find a replacement for these libraries to help the visualizer run faster.

Daryl Ann Winstead (Mekong River Basin Agriculture) 19-08-2016, 12:24

Hi Katie! Interesting! Thank you for your response!

Emily Gotschalk 16-08-2016, 08:48

Great video! How do you expect this software to spread to other science teams utilizing CALIPSO data once testing is completed?

Katie Moore 19-08-2016, 10:50

Thanks, Emily! Once it *finally* goes open source, we’ll let Dr. Chip Trepte start the spread of the word.

Teresa Martinez 11-08-2016, 21:07

Would you be able to use this software with other electronic hardware devices. For example if you want to collect data (temp)at any given place and time. Would you be able to take your electronic hardware device and it would register the temp/weather/humidity at that time.

Also, does this software show how the aerosols effect water conditions/quality.

Katie Moore 19-08-2016, 10:56

Hi Teresa, thanks for your questions. We haven’t yet tested the software on tablets; I suspect that there will have to be some changes to get the software to run on them. Hopefully, we can make this a web application, and then it won’t matter what hardware is running it underneath. With regards to the other question, the software just displays HDF data from CALIPSO, so it relies on the expertise of the user to make connections to other weather/climatic conditions

Adama BA 20-08-2016, 21:12

Hi Teresa, thank you for your interest. To just add on what Katie said, we updated VOCAL software to display level 2 data and added an Ice/water Phase feature which will help identify the water phase of clouds. And I think it is a good step towards understanding how aerosols affects water conditions/quality.

Teresa Martinez 11-08-2016, 20:53

I am not to familiar with scientific software, but a thought I had was would this software be compatible with touchscreen tablets.

Tristan Adams 11-08-2016, 20:51

Can this find Elsa?

Teresa Fenn 11-08-2016, 15:50

This is a really cool application! What are your plans to spread the word about it?

Katie Moore 19-08-2016, 10:58

Thanks Teresa! Once it goes open source, we can put a copy on DEVELOP’s GitHub site, then get on our partner and the whole CALIPSO Science Team to start spreading the word in their community.


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