# Unexpected time-mean parameters returned from API download request

**URL:** <https://forum.ecmwf.int/t/unexpected-time-mean-parameters-returned-from-api-download-request/7071>\
**Category:** Datasets and Usage\
**Tags:** era5\
**Created:** [18 October 2024 21:34 UTC](https://forum.ecmwf.int/t/unexpected-time-mean-parameters-returned-from-api-download-request/7071 "2024-10-18T21:34:50Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Earth\_Engine](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/e/46a35a/32.png) [@Earth\_Engine](https://forum.ecmwf.int/u/Earth_Engine)\
**Post date:** [18 October 2024 21:34 UTC](https://forum.ecmwf.int/t/unexpected-time-mean-parameters-returned-from-api-download-request/7071/1 "2024-10-18T21:34:50Z")

</div>

We use the API to download netcdf files for datasets like `reanalysis-era5-single-levels-monthly-means`, and among the variables we request are `k_index` and `total_totals_index`. The subdataset names in the returned netcdf files are expected to be `kx` and `totalx`, respectively, based on table 2 [here](https://confluence.ecmwf.int/display/CKB/ERA5%3A+data+documentation#heading-Table2surfaceandsinglelevelparametersinstantaneous).

However, the file we get back instead contains the time-mean versions of those parameters, `avg_kx` and `avg_totalx`. Is this because the dataset is monthly means? We’ve only started validating our downloads by checking the subdataset names so it’s possible that we’ve only run into this now because we only counted the number of subdatasets before.