I want to download GeoTIFF files of TRMM product 3B42. (This is a rainfall estimate derived from multiple sensors of the Tropical Rainfall Measuring Mission satellite.)

The NASA/Goddard Precipitation Measurement Missions website directs me to the TRMMopen ftp Server: ftp://trmmopen.gsfc.nasa.gov/trmmdata/GIS

However, this sporadically asks for username and password. How can I get them?
Is there an alternative way to obtain this dataset?

I need precipitation data for each 365 days and 12 month of 2013, so downloading each file one by one is quite tedious.

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    If commercial data, pay for an account. If not, what have you tried? Either way, contact the data provider, if anyone can help you it's them. – Martin Apr 23 '14 at 9:50
  • This question is about downloading data and access to a government web site. Please contact them on access. – Mapperz Apr 23 '14 at 13:32
  • This question probably lacks detail. But I do not see why it has been closed. (1) TRMM 3B42 is a remote sensing data set (climate data) (2) The NASA websites point to this particular ftp server for data download; the data is freely available if you cite properly. The login request occurs sporadically. (3) The variety of available download portals is not intuitive and probably confusing - GIS.SE uses are likely to have experience. Of course it is a good idea to contact the data provider. But why not ask here, if details are implemented? The pointer to Super User is confusing. – lavarider Apr 23 '14 at 16:30
  • thank you lavarider I sent data provider an email and they told me what input the username and password but that did not work. I need precipitation data for each 365 days and 12 month of 2013 but I can download just one everytime without username and password!!! – hadis Apr 23 '14 at 17:31
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    Super User seemed an odd choice to me too, but perhaps the Open Data (beta) Stack Exchange would be a candidate site for migration/asking. It seems strange that the data custodian would provide a username and password that does not work. I would certainly follow up on that with them if I was anxious for the data. – PolyGeo Apr 25 '14 at 8:41

Do not download multiple files at once / use different ftp client

You are downloading from TRMMopen (which is an official download source of the NASA / Goddard PMM) via anonymous ftp. You are only prompted a username/password dialogue if you have multiple connections to this ftp site, e.g. because you are attempting to download more then one file at once.

Instead, try to download one file after another (possibly with a short delay). You won't get the password prompt then.

EDIT: If you used a web browser to download the data, use a decent ftp client instead (which keeps the connection between downloads) . I tested this with a variety of ftp clients, and I had no problems to download larger datasets!

Note that you could contact the data provider and ask for alternatives in order to obtain larger datasets. They offer something like a data subscription service in their FAQ:

"I would like to receive all new files generated for a data product, over a given time period, at a specified time interval (e.g., weekly). Can I set up a procedure by which specified data will be sent to me automatically?"

Yes, just contact help@disc.gsfc.nasa.gov (or 301-614-5224, voice; or 301-614-5268, fax) and request a "subscription." Information that would be needed from you are data product(s) desired, begin date, and end date. You will receive an email notification whenever data are ready for FTP pickup.

Hovever there are alternative download sources which are probably more suited for downloading larger datasets:

Alternative download sources

The data is available via STORM (Science Team On-Line Request Module):

I highly recommend that you have a look at it:

PPS Data Access - to search for GPM and TRMM data, order custom subsets and set up subscriptions.
PPS Public Archive - to access GPM and TRMM standard products via online ftp.

Use it to obtain custom, larger subsets of TRMM data at once.

They also provide a different link to the ftp server which also features the 3B42 data. (I do not know if similar connection restrictions apply there though.)

Of course you can also get the data via http from GES DISC mirador, (but this is probably more suitable for single files), or use TOVAS.

Data access policy

Of course, be sure to conform to the the data access policy which can be found in the 3B42 / 3B43 documentation (p.40). Also, have a look at the (quite open) usage policy of the GES DISC.

The different types of TRMM data products have also been addressed in a GIS.SE question about TRMM data download.

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  • thank you so much for your guidance. that was very useful. may I ask you more questions that may arise later? – hadis Apr 23 '14 at 17:47
  • You can accept the answer if it was helpful and fully addresses your posted issue. Of course you can ask more questions to the GIS.SE community. The guidance "How to frame a good question" is definitely worth a look; try to provide enough details in your future questions, about what you have done and what you are trying to achieve in order to elicit comprehensive answers. (For example, in this question, the rough amount of the data you need is a helpful detail.) – lavarider Apr 25 '14 at 6:56

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