How to access the data - tnipen/NWPdocs GitHub Wiki

Our weather forecast data is available in NetCDF format on https://thredds.met.no/thredds/metno.html. The files follow the NetCDF/CF conventions. The thredds website lets you browse the files and give access URL to each file.

Note also, that all communication to the thredds-server at Met requires a HTTPS connection, any HTTP-request reply with http error code 410: (410 Gone).

Navigating Thredds

When accesing the Weather Forecasts directory, the following screen greets you:

Other products includes ocean-modeldata and others. Will be explained more (Currently explained on: https://drive.google.com/file/d/0B3vvF5TQcILySGZEX1ViY2VlYms/view). Old forecast products includes products that were produced as part of the daily operation but now kept for archiving. Will be explained more (Currently explained on: https://drive.google.com/file/d/0B-SaEtrDE91WWDkzY3dpZlU1V00/view)

Extracting data

There are two ways to downloading data: 1) Download the whole file via https. This requires large bandwidth and is often not needed. We do not recommend this approach, unless all data is required. 2) Access using the OPeNDAP-protocol. With this approach you only stream the data you need. Most programming languages support access via OpenDAP.

Subsetting using OPeNDAP web access form

Subsetting using NetCDF libraries

See Python, guides will be added for R and (maybe) a lower level (C-type) language

Subsetting using Fimex

The WMO has approved the GRIB-format for efficiently transmitting meteorological gridded data, so this is one of the preferred formats for exchanging data between meteorological services. GRIB has been around for some 35 years - since before the Internet and the PC was invented - with minimal changes to the format.

Being able to read GRIB data yourself, gives you the capacity to access gridded meteorological information from the weather services on the lowest possible level. This can be an advantage if you are looking for a reliable starting point for your data processing chain, which you plan to run with as little interruption as possible for the next decades to come.

Some basic receipts for installing and running the Fimex software for reading and interpolation GRIB2 files on Ubuntu are readily available here.