Access to CALIPSO data

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benhurmp
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Joined: Thu Oct 08, 2020 3:58 pm America/New_York

Access to CALIPSO data

by benhurmp » Mon Dec 14, 2020 9:08 pm America/New_York

Hello everyone,

In the last Friday (December 11) I made a request to download data (in hdf) from CALIPSO for 3 months for the Amazon region, and I still haven't got access to download the data. I'm afraid because I'm doing a research on the distribution of cirrus clouds in this region and for that I need data from the CALIPSO 2006-2019 period, however it's a large volume of data, so it may take too much time to request to be processed and I get access to download the data. I know that I can get direct access to the files through this link:
https://asdc.larc.nasa.gov/data/CALIPSO ... ard-V4-20/

But I think this link provides data for the entire planet, and I don't know how to restrict it to just the region I need (rectangle of coordinates -12.5 S, 2.5 N, -74 to -50 W). Is there any way I can get direct download of the data within the required region? Thank you.

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ASDC - mcook
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Re: Access to CALIPSO data

by ASDC - mcook » Tue Dec 15, 2020 11:18 am America/New_York

Thank you for contacting us with an interest in CALIPSO data.
Please tell us what order tool did you use to order the CALIPSO data?
Your response will help us to better assist you.

benhurmp
Posts: 8
Joined: Thu Oct 08, 2020 3:58 pm America/New_York

Re: Access to CALIPSO data

by benhurmp » Wed Dec 16, 2020 9:47 pm America/New_York

Thank you for answer me,
I used the Earthdata Search:
https://search.earthdata.nasa.gov/searc ... 90005174!4!!

In it I selected the rectangle of the region I need, and also the first three months within the time range I need. In the download section It's shown that the download method is 'Stage For Delivery - ECHO Orders'. I need to download data from the 2006-2019 period (which results in approximately 416 GB of data), so I'd like to know the most efficient way to get the download of these data. I would appreciate very much if you can help me :)

ASDC - mcook
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Re: Access to CALIPSO data

by ASDC - mcook » Thu Dec 17, 2020 3:32 pm America/New_York

We have two suggestions for you.
1. If you are subsetting the data, meaning you only need parts of a file, we suggest the CALIPSO Search and Subset Tool: https://subset.larc.nasa.gov/calipso

2. If you need the file in its entirety, we suggest the asdc website:
https://asdc.larc.nasa.gov/data/CALIPSO/

Additionally, there is a Wget script available for downloading data from the ASDC website:
This script was provided to user's by our developer. You should be able to download the entire directory. This is an example of the script.

URL=https://asdc.larc.nasa.gov/data/CALIPSO ... rov-V3-40/
USERNAME=<your Earthdata login username>
PASSWORD=<your Earthdata login password>

You should perform this session on your computer terminal:
cd ~
touch .netrc
echo "machine urs.earthdata.nasa.gov login $USERNAME password $PASSWORD" > .netrc
chmod 0600 .netrc
touch .urs_cookies
wget --load-cookies ~/.urs_cookies --save-cookies ~/.urs_cookies --auth-no-challenge=on --keep-session-cookies --content-disposition --recursive --wait=60 --no-parent --reject "index.html*" --execute robots=off $URL

Please let us know if you have questions.

benhurmp
Posts: 8
Joined: Thu Oct 08, 2020 3:58 pm America/New_York

Re: Access to CALIPSO data

by benhurmp » Tue Dec 22, 2020 11:44 am America/New_York

Hello,

I downloaded the data using the first option offered, and realized that the downloaded files are only 3.5 MB on average, while downloading by the second option, the average size is 45 MB. Although I choose to select all data parameters (under 'Selected Parameter Group (s)') in the first option, the fact that there is a smaller file size makes me think that something is missing. In the second option, I don't know how to restrict the download to the region of interest for my search (-12.5 S, 2.5 N, -74 to -50 W), as the data is organized by date only. Can you shed some light on this? Thank you very much.

ASDC - mcook
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Re: Access to CALIPSO data

by ASDC - mcook » Wed Dec 23, 2020 10:39 am America/New_York

The first option: the CALIPSO Search and Subset Tool: The files are subsetted meaning only portions of a full file are selected according to the parameters you have chosen. So, the file will be smaller.

The second option: the Direct Data Download (DDD) tool provides the entire file. Therefore the files will be larger in MB. No spaitial criteria, only temporal (dates) can be specified.

We recommend you use the CALIPSO Search and Subset Tool to satisfy your spatial, temporal, and parameters criteria. https://subset.larc.nasa.gov/calipso/

In Step 3: Select a geospatial range (optional) of the CALIPSO Search and Subset Tool you can specify your locations by: a) typing in the longitudes and latitudes in the Top, Bottom, Left, Right boxes or: b) Use your mouse on the map to draw a bounding box by clicking and dragging. The longitudes and latitudes will automatically show in the Top, Bottom, Left, Right on the left.

Let us know if you have questions.

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