Reanalysis data for 36 point locations

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Reanalysis data for 36 point locations

by EarthdataForumContributor » Thu May 28, 2020 4:52 pm America/New_York

Hi,
I'm interested in time series of daily precipitation rate data for 36 point locations in the European Alps from several reanalysis datasets (ERA-interim, ERA-5, NCEP/NCAR, MERRA-2).

Is there a way to obtain this data without the need to download thousands of files?

GES DISC - jimacker
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Re: Reanalysis data for 36 point locations

by GES DISC - jimacker » Thu May 28, 2020 4:56 pm America/New_York

The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), provides MERRA-2 data. You may download time series at your specific point locations through the GDS ( GrADS Data Server) service.

Here is the How-to document that provides an example:
https://disc.gsfc.nasa.gov/information/ ... le%20Point

The MERRA-2 data file specific and document:
https://gmao.gsfc.nasa.gov/pubs/docs/Bosilovich785.pdf

https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/docs/

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You can open the GDS URL in Python using the netCDF4 module. The following example demonstrates how to extract attributes and other information, plus it prints the first three values in a time series at x=120,y=180:


import netCDF4 as nc4
url = 'https://goldsmr4.gesdisc.eosdis.nasa.gov/dods/M2IMNXASM'
f = nc4.Dataset(url,'r')
ps = f['ps']
keys = ps.ncattrs()
print(keys)
FV = ps.getncattr('_FillValue')
units = ps.getncattr('units')
print(ps.shape)

t0 = ps[0][180][120]
t1 = ps[1][180][120]
t2 = ps[1][180][120]
print(t0,t1,t2)

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You can also open the URL for it with pydap:

from pydap.client import open_url
from pydap.cas.urs import setup_session
myurl='https://goldsmr4.gesdisc.eosdis.nasa.gov/dods/M2I1NXASM'
username='put-your-earthdata-login-name-here'
password='put-your-password-here'
session = setup_session(username, password, check_url=myurl)
f = open_url(myurl, session=session)

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