# \#netcdf **URL:** https://forum.ecmwf.int/tag/netcdf/60.md [Latest](https://forum.ecmwf.int/latest.md) · [Categories](https://forum.ecmwf.int/categories.md) · [Tags](https://forum.ecmwf.int/tags.md) --- ## [Issues using CDO with netCDF](https://forum.ecmwf.int/t/issues-using-cdo-with-netcdf/14600)
**Author:** [@Christopher\_Wright](https://forum.ecmwf.int/u/Christopher_Wright)\ **Replies:** 0\ **Last updated:** [13 January 2026 22:21 UTC](https://forum.ecmwf.int/t/issues-using-cdo-with-netcdf/14600 "2026-01-13T22:21:37Z")
Recently, my CDS downloads (always as netCDFs) have been somehow incompatible to cdo operators. A simple remapping which normally takes seconds can take hours. I’ve been able to fix the issue with a script that chunks th… --- ## [Changes to grib to netCDF converter on CDS-Beta/ADS-Beta](https://forum.ecmwf.int/t/changes-to-grib-to-netcdf-converter-on-cds-beta-ads-beta/4322)
**Author:** [@Kevin\_Marsh](https://forum.ecmwf.int/u/Kevin_Marsh)\ **Replies:** 36\ **Last updated:** [25 December 2025 17:16 UTC](https://forum.ecmwf.int/t/changes-to-grib-to-netcdf-converter-on-cds-beta-ads-beta/4322 "2025-12-25T17:16:25Z")
The new CDS-Beta/ADS-Beta system uses cfgrib for the grib to netCDF conversion. This converter is labelled as “experimental”, as it is still under development. The same convertor is used for direct downloads and post-pr… --- ## [Using CAMS data from global atmospheric composition forecasts as IC and BC in WRF-Chem. Trouble Converting GRIB to NetCDF](https://forum.ecmwf.int/t/using-cams-data-from-global-atmospheric-composition-forecasts-as-ic-and-bc-in-wrf-chem-trouble-converting-grib-to-netcdf/1135)
**Author:** [@Maria\_Francisca\_Card](https://forum.ecmwf.int/u/Maria_Francisca_Card)\ **Replies:** 3\ **Last updated:** [26 November 2025 15:21 UTC](https://forum.ecmwf.int/t/using-cams-data-from-global-atmospheric-composition-forecasts-as-ic-and-bc-in-wrf-chem-trouble-converting-grib-to-netcdf/1135 "2025-11-26T15:21:40Z")
Dear all, I downloaded CAMS data from global atmospheric composition forecast for a simulation with WRF-Chem following the instructions How to run the WRF-Chem model using CAMS data as initial and boundary conditions (B… --- ## [Very high transpiration values in ERA5 Land Hourly](https://forum.ecmwf.int/t/very-high-transpiration-values-in-era5-land-hourly/11714)
**Author:** [@Karan\_Mahajan](https://forum.ecmwf.int/u/Karan_Mahajan)\ **Replies:** 5\ **Last updated:** [3 November 2025 14:00 UTC](https://forum.ecmwf.int/t/very-high-transpiration-values-in-era5-land-hourly/11714 "2025-11-03T14:00:08Z")
Hello everyone, I am doing some analysis with transpiration values. For this I downloaded the variable ‘Evaporation from Vegetation Transpiration’ from ERA5 Land Hourly data. Time range is 1 Jan 2010 to 31 Dec 2013. I d… --- ## [Problems Parsing .NC Files After Outage](https://forum.ecmwf.int/t/problems-parsing-nc-files-after-outage/8060)
**Author:** [@Peter\_Akers](https://forum.ecmwf.int/u/Peter_Akers)\ **Replies:** 9\ **Last updated:** [14 May 2025 21:29 UTC](https://forum.ecmwf.int/t/problems-parsing-nc-files-after-outage/8060 "2025-05-14T21:29:28Z")
Hi All, is anyone else having trouble processing .NC files since the service was back online? I’m still investigating the issue from my end but from what I can see, it looks like something in the output has changed that… --- ## [Huge performance drop when reading new ERA5 netcdf4 format](https://forum.ecmwf.int/t/huge-performance-drop-when-reading-new-era5-netcdf4-format/12831)
**Author:** [@Theo\_Mathurin](https://forum.ecmwf.int/u/Theo_Mathurin)\ **Replies:** 2\ **Last updated:** [6 May 2025 15:15 UTC](https://forum.ecmwf.int/t/huge-performance-drop-when-reading-new-era5-netcdf4-format/12831 "2025-05-06T15:15:31Z")
We routinely collect ERA5 data in netCDF (more specifically pressure level reanalyses). From 18th of September 2024 onwards, we have received the new netCDF4 format. Apart from the breaking changes in file structure whi… --- ## [Limitation change on netCDF ERA5 requests](https://forum.ecmwf.int/t/limitation-change-on-netcdf-era5-requests/12477)
**Author:** [@Michela](https://forum.ecmwf.int/u/Michela)\ **Replies:** 4\ **Last updated:** [6 May 2025 07:50 UTC](https://forum.ecmwf.int/t/limitation-change-on-netcdf-era5-requests/12477 "2025-05-06T07:50:21Z")
As many users will have already noticed, a change has recently been implemented in some ERA5 datasets with respect to the retrieval of data in NetCDF format versus GRIB format. The native ERA5 data is in GRIB format. Wh… --- ## [Clarification on ERA5 Hourly Data Variable Names](https://forum.ecmwf.int/t/clarification-on-era5-hourly-data-variable-names/12263)
**Author:** [@Alessandro\_De\_Lorenzis](https://forum.ecmwf.int/u/Alessandro_De_Lorenzis)\ **Replies:** 6\ **Last updated:** [4 April 2025 08:49 UTC](https://forum.ecmwf.int/t/clarification-on-era5-hourly-data-variable-names/12263 "2025-04-04T08:49:49Z")
Dear all, I am writing to ask for some information regarding data from the ERA5 hourly data on single levels from 1940 to present dataset. In September 2024, I downloaded the following variables from the website: Mea… --- ## [A bug in cdsapi ERA5 Table 12 download](https://forum.ecmwf.int/t/a-bug-in-cdsapi-era5-table-12-download/11802)
**Author:** [@Teijo\_Arponen](https://forum.ecmwf.int/u/Teijo_Arponen)\ **Replies:** 1\ **Last updated:** [10 March 2025 15:14 UTC](https://forum.ecmwf.int/t/a-bug-in-cdsapi-era5-table-12-download/11802 "2025-03-10T15:14:07Z")
I found a bug in downloading ERA5 Table 12 data. When downloading parameter list including paramIds 129 (geopotential) and 152 (log of surf pressure), all other parameters are ignored. If I omit 129 and 152 from the para… --- ## [ERA5 shortname changed from msdwswrf to avg\_sdswrf?](https://forum.ecmwf.int/t/era5-shortname-changed-from-msdwswrf-to-avg-sdswrf/10960)
**Author:** [@Jerl\_Simpson](https://forum.ecmwf.int/u/Jerl_Simpson)\ **Replies:** 1\ **Last updated:** [24 January 2025 13:45 UTC](https://forum.ecmwf.int/t/era5-shortname-changed-from-msdwswrf-to-avg-sdswrf/10960 "2025-01-24T13:45:06Z")
Hi: I’m wondering if the short name for Mean surface downward short-wave radiation flux has been changed with out the documentation update. Our scripts broke today and upon inspection it looks as if the previous shor… --- ## [NetCDF variable expver not CF compliant in ERA5 - new converter](https://forum.ecmwf.int/t/netcdf-variable-expver-not-cf-compliant-in-era5-new-converter/7148)
**Author:** [@Alistair\_Sellar](https://forum.ecmwf.int/u/Alistair_Sellar)\ **Replies:** 1\ **Last updated:** [26 December 2024 09:43 UTC](https://forum.ecmwf.int/t/netcdf-variable-expver-not-cf-compliant-in-era5-new-converter/7148 "2024-12-26T09:43:41Z")
ERA5 netCDF data from the new grib to netCDF converter contains a variable which is not CF compliant. The file claims to use CF conventions version 1.7, but running it through the CF checker produced a Invalid variable t… --- ## [Forthcoming update to the format of netCDF files produced by the conversion of GRIB data on the CDS](https://forum.ecmwf.int/t/forthcoming-update-to-the-format-of-netcdf-files-produced-by-the-conversion-of-grib-data-on-the-cds/7772)
**Author:** [@Michela](https://forum.ecmwf.int/u/Michela)\ **Replies:** 9\ **Last updated:** [18 December 2024 08:56 UTC](https://forum.ecmwf.int/t/forthcoming-update-to-the-format-of-netcdf-files-produced-by-the-conversion-of-grib-data-on-the-cds/7772 "2024-12-18T08:56:50Z")
We are pleased to announce an update to the format of netCDF files produced by the conversion of GRIB data on the CDS. The new release will take place on Tuesday 26 November 2024. The main improvement is that when conve… --- ## [New time format in ERA5 netcdf files](https://forum.ecmwf.int/t/new-time-format-in-era5-netcdf-files/3796)
**Author:** [@Sigalit\_Berkovic](https://forum.ecmwf.int/u/Sigalit_Berkovic)\ **Replies:** 9\ **Last updated:** [27 November 2024 12:13 UTC](https://forum.ecmwf.int/t/new-time-format-in-era5-netcdf-files/3796 "2024-11-27T12:13:54Z")
Hi ! While downloading ERA5 data on pressure levels ( T u v) I noticed that the data downloaded from the new site has new time format. The reference time is 1/1/1970 while previously it was 1/1/1900. ncview can not d… --- ## [CDS-Beta : Conditions: Missing Parameters (scale\_factor , add\_offset) in .nc file](https://forum.ecmwf.int/t/cds-beta-conditions-missing-parameters-scale-factor-add-offset-in-nc-file/4684)
**Author:** [@Anil\_Teella](https://forum.ecmwf.int/u/Anil_Teella)\ **Replies:** 4\ **Last updated:** [31 October 2024 14:48 UTC](https://forum.ecmwf.int/t/cds-beta-conditions-missing-parameters-scale-factor-add-offset-in-nc-file/4684 "2024-10-31T14:48:39Z")
Hi, We have downloaded the files from new platform and notice that the parameters/keys used by us (scale\_factor , add\_offset) are missing in the files downloaded from CDS-Beta. How can we access those parametes, Where… --- ## [Error: Assertion failed, while reading "Temperature Statistics"](https://forum.ecmwf.int/t/error-assertion-failed-while-reading-temperature-statistics/7151)
**Author:** [@Franziska\_Mueller](https://forum.ecmwf.int/u/Franziska_Mueller)\ **Replies:** 2\ **Last updated:** [25 October 2024 10:15 UTC](https://forum.ecmwf.int/t/error-assertion-failed-while-reading-temperature-statistics/7151 "2024-10-25T10:15:06Z")
I am getting an Error, while reading from the following dataset: Temperature statistics for Europe derived from climate projections The error does not occur every time. Sometimes everything works fine. Here is the err… --- ## [Date coordinate in monthly ERA5 netcdf - new converter](https://forum.ecmwf.int/t/date-coordinate-in-monthly-era5-netcdf-new-converter/7147)
**Author:** [@Alistair\_Sellar](https://forum.ecmwf.int/u/Alistair_Sellar)\ **Replies:** 1\ **Last updated:** [23 October 2024 09:48 UTC](https://forum.ecmwf.int/t/date-coordinate-in-monthly-era5-netcdf-new-converter/7147 "2024-10-23T09:48:18Z")
Monthly mean netCDF files contain a date coordinate instead of a CF-compliant time coordinate. The date coordinate is an integer representing days, months, and year in the units, hundreds and ten-thousands. variables: … --- ## [ERA5 Forecast Accumulation netCDF Download Error](https://forum.ecmwf.int/t/era5-forecast-accumulation-netcdf-download-error/1187)
**Author:** [@Frederick\_Soster](https://forum.ecmwf.int/u/Frederick_Soster)\ **Replies:** 3\ **Last updated:** [16 October 2024 08:23 UTC](https://forum.ecmwf.int/t/era5-forecast-accumulation-netcdf-download-error/1187 "2024-10-16T08:23:51Z")
Hello all, When I attempt to download ERA5 forecast data from the complete ERA5 archive (e.g. https://apps.ecmwf.int/data-catalogues/era5/?stream=oper&levtype=sfc&expver=1&month=dec&year=1979&type=fc&class=ea) in netCDF… --- ## [Inclusion of Model Level Coefficients (ak/bk) in ERA5 NetCDF Downloads](https://forum.ecmwf.int/t/inclusion-of-model-level-coefficients-ak-bk-in-era5-netcdf-downloads/6864)
**Author:** [@christoph.fischer](https://forum.ecmwf.int/u/christoph.fischer)\ **Replies:** 0\ **Last updated:** [14 October 2024 08:10 UTC](https://forum.ecmwf.int/t/inclusion-of-model-level-coefficients-ak-bk-in-era5-netcdf-downloads/6864 "2024-10-14T08:10:46Z")
Dear all, I am curious about the absence of the ak/bk (hybrid) coefficients in the ERA5 model level downloads in NetCDF format. It’s noteworthy that these coefficients are included in the GRIB format, which is sufficien… --- ## [Check your recent NetCDF files downloaded from the CDS and ADS: you may need to download them again](https://forum.ecmwf.int/t/check-your-recent-netcdf-files-downloaded-from-the-cds-and-ads-you-may-need-to-download-them-again/2280)
**Author:** [@Anabelle](https://forum.ecmwf.int/u/Anabelle)\ **Replies:** 14\ **Last updated:** [22 April 2024 11:18 UTC](https://forum.ecmwf.int/t/check-your-recent-netcdf-files-downloaded-from-the-cds-and-ads-you-may-need-to-download-them-again/2280 "2024-04-22T11:18:06Z")
We were made aware of an issue which gave wrong data in NetCDF format from the Climate Data Store (CDS) and the Atmosphere Data Store (ADS). This happened when the raw data is in the GRIB format, for example, ERA5. Pleas… --- ## [You may need to re-download data from the CDS](https://forum.ecmwf.int/t/you-may-need-to-re-download-data-from-the-cds/2548)
**Author:** [@Xiaobo\_Yang](https://forum.ecmwf.int/u/Xiaobo_Yang)\ **Replies:** 2\ **Last updated:** [20 April 2024 20:09 UTC](https://forum.ecmwf.int/t/you-may-need-to-re-download-data-from-the-cds/2548 "2024-04-20T20:09:15Z")
Dear user, If you have downloaded data in the NetCDF format from the CDS between 9:45UTC 18th April 2024 and 16:20UTC 19th April 2024, please re-download the data. There was a problem causing GRIB to NetCDF conversion g… --- ## [Negative values in ERA5 runoff](https://forum.ecmwf.int/t/negative-values-in-era5-runoff/1111)
**Author:** [@Yuqi\_Zhang](https://forum.ecmwf.int/u/Yuqi_Zhang)\ **Replies:** 0\ **Last updated:** [25 December 2023 14:00 UTC](https://forum.ecmwf.int/t/negative-values-in-era5-runoff/1111 "2023-12-25T14:00:18Z")
Hi everyone, Does anyone know why there are negative values in the runoff? Is it an error? I saw the topic that someone found negative values in precipitation and the answer says it's caused by conversion from grib form… --- ## [Cordex- cds api](https://forum.ecmwf.int/t/cordex-cds-api/921)
**Author:** [@Mateo\_Carmona\_Carras](https://forum.ecmwf.int/u/Mateo_Carmona_Carras)\ **Replies:** 0\ **Last updated:** [21 December 2023 08:35 UTC](https://forum.ecmwf.int/t/cordex-cds-api/921 "2023-12-21T08:35:43Z")
Dear all, My name is Mateo Carmona and I work in the Sustainable Finance department at Mazars Spain as a Data Analyst as well in the Barcelona office. Through a request to the CDS API, I have obtained data relevant… --- ## [Climate and Forecast conventions on NetCDF files (CDS API and CDS Toolbox)](https://forum.ecmwf.int/t/climate-and-forecast-conventions-on-netcdf-files-cds-api-and-cds-toolbox/1050)
**Author:** [@UnknownUser](https://forum.ecmwf.int/u/UnknownUser)\ **Replies:** 1\ **Last updated:** [10 August 2023 18:57 UTC](https://forum.ecmwf.int/t/climate-and-forecast-conventions-on-netcdf-files-cds-api-and-cds-toolbox/1050 "2023-08-10T18:57:58Z")
Hello, I have noticed that when we retrieve data from the climate data store or from the API, netCDF files use the CF-1.6 conventions. However, when we want to retrieve data from the CDS Toolbox it uses the CF - 1.7 con… --- ## [GRIB to NetCDF File | Download as NetCDF File](https://forum.ecmwf.int/t/grib-to-netcdf-file-download-as-netcdf-file/1397)
**Author:** [@Kim\_Cholibois](https://forum.ecmwf.int/u/Kim_Cholibois)\ **Replies:** 7\ **Last updated:** [10 July 2023 06:59 UTC](https://forum.ecmwf.int/t/grib-to-netcdf-file-download-as-netcdf-file/1397 "2023-07-10T06:59:21Z")
Dear all, I have been trying to download Arctic regional reanalysis on single levels from 1991 to present for the following parameters: 10m wind direction, 10m wind speed, 2m temperature, Albedo, Surface net solar radia… --- ## [CMIP6 - NetCDF file with Inconsistent variable definition for lat\_bnds!](https://forum.ecmwf.int/t/cmip6-netcdf-file-with-inconsistent-variable-definition-for-lat-bnds/1353)
**Author:** [@Daniel\_Victoria](https://forum.ecmwf.int/u/Daniel_Victoria)\ **Replies:** 5\ **Last updated:** [8 May 2023 10:10 UTC](https://forum.ecmwf.int/t/cmip6-netcdf-file-with-inconsistent-variable-definition-for-lat-bnds/1353 "2023-05-08T10:10:20Z")
I'm downloading daily CMIP6 data for max air temperature. I've asked for a spatial subset covering Brazil. When I open the NetCDF file in Panoply, I get very strange image, with the values from the most eastern border… --- ## ["grib\_to\_netcdf ERROR" while downloading via cdsapi (Python module)](https://forum.ecmwf.int/t/grib-to-netcdf-error-while-downloading-via-cdsapi-python-module/1392)
**Author:** [@johannes\_hampp](https://forum.ecmwf.int/u/johannes_hampp)\ **Replies:** 4\ **Last updated:** [11 April 2023 12:56 UTC](https://forum.ecmwf.int/t/grib-to-netcdf-error-while-downloading-via-cdsapi-python-module/1392 "2023-04-11T12:56:13Z")
When downloading a large dataset using the Python module cdsapi , I get strange errors (see below) seemingly related to too large datafiles and the use of the old (classic) netCDF file format. I can circumvent the error… --- ## [Total Precipitation \[Values not in range\] - ERA5-Land hourly data from 1981 to present](https://forum.ecmwf.int/t/total-precipitation-values-not-in-range-era5-land-hourly-data-from-1981-to-present/1128)
**Author:** [@Giuseppe\_Gerardi](https://forum.ecmwf.int/u/Giuseppe_Gerardi)\ **Replies:** 14\ **Last updated:** [24 February 2023 13:34 UTC](https://forum.ecmwf.int/t/total-precipitation-values-not-in-range-era5-land-hourly-data-from-1981-to-present/1128 "2023-02-24T13:34:43Z")
I'm facing some trouble in calculating the value of the total precipitation in Italian Cities using the 'Total Precipitation' variable from the "ERA5-Land hourly data from 1981 to present" dataset. As example of my prob… --- ## [Oras5 lat lon grid (that is nat\_lan, nat\_lon in \*.nc files read in by xarray)](https://forum.ecmwf.int/t/oras5-lat-lon-grid-that-is-nat-lan-nat-lon-in-nc-files-read-in-by-xarray/1662)
**Author:** [@Markus\_Kaukonen](https://forum.ecmwf.int/u/Markus_Kaukonen)\ **Replies:** 2\ **Last updated:** [31 December 2022 02:43 UTC](https://forum.ecmwf.int/t/oras5-lat-lon-grid-that-is-nat-lan-nat-lon-in-nc-files-read-in-by-xarray/1662 "2022-12-31T02:43:55Z")
What is the oras5 lat lon grid like? I read singles variable sst nc file like by ds = xr.open\_dataset('sosstsst\_control\_monthly\_highres\_2D\_198008\_CONS\_v0.1.nc', engine="netcdf4") and it seems that lat lon grid is… --- ## [Nc files of ERA5-complete can not read in matlab2021b](https://forum.ecmwf.int/t/nc-files-of-era5-complete-can-not-read-in-matlab2021b/943)
**Author:** [@X\_DW](https://forum.ecmwf.int/u/X_DW)\ **Replies:** 5\ **Last updated:** [30 November 2022 13:52 UTC](https://forum.ecmwf.int/t/nc-files-of-era5-complete-can-not-read-in-matlab2021b/943 "2022-11-30T13:52:49Z")
Error using the matlab.internal.imagesci.net cdflib NetCDF library encounters an error during the execution of 'open' function - 'Unknown file format (NC ENOTNC)'. Error netcdf. Open (line 67) \[varargout {that}\] = matl… --- ## [ERA5 requests for atmospheric and wave variables in netcdf](https://forum.ecmwf.int/t/era5-requests-for-atmospheric-and-wave-variables-in-netcdf/1628)
**Author:** [@Kevin\_Marsh](https://forum.ecmwf.int/u/Kevin_Marsh)\ **Replies:** 1\ **Last updated:** [20 July 2022 13:06 UTC](https://forum.ecmwf.int/t/era5-requests-for-atmospheric-and-wave-variables-in-netcdf/1628 "2022-07-20T13:06:24Z")
We advise users to request ERA5 ocean and atmospheric variables separately if asking for the data in netCDF format. Atmosphere parameters are stored on a 0.25° grid, while wave parameters are on a 0.5° grid. Unfortunate… [Next page](https://forum.ecmwf.int/tag/netcdf/60.md?match_all_tags=true&page=1&tags%5B%5D=netcdf)