# Merge ERA5-Land and ERA5 coastal cells

**URL:** <https://forum.ecmwf.int/t/merge-era5-land-and-era5-coastal-cells/846>\
**Category:** C3S - Datasets and Usage\
**Tags:** c3s, era5, era5-land\
**Created:** [2 March 2022 09:58 UTC](https://forum.ecmwf.int/t/merge-era5-land-and-era5-coastal-cells/846 "2022-03-02T09:58:26Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Nikolaos\_Alexandris](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/n/5e9695/32.png) [@Nikolaos\_Alexandris](https://forum.ecmwf.int/u/Nikolaos_Alexandris)\
**Post date:** [2 March 2022 09:58 UTC](https://forum.ecmwf.int/t/merge-era5-land-and-era5-coastal-cells/846/1 "2022-03-02T09:58:26Z")

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ERA5-Land contains finer-scale information of the land surface component than ERA5.&nbsp; The land-sea mask used to mask out sea, is a fractional land coverage raster map.&nbsp; Cells with a fraction of land \< 0.5 are not considered to be land (see attached map below, red shows cells with a land coverage between **(0, 0.5)**).

In ERA5-Land data, what is the recommended way to fill in all those coastal cells which are not considered as land &nbsp;(land coverage \< 0.5) with ERA5 data?&nbsp; I can imagine various solutions, yet it would be nice to have some recommendation if experience is already there.

##### **Related material**

- [Land-Sea Mask](https://confluence.ecmwf.int#)
- [Land-sea mask (netCDF file)](https://confluence.ecmwf.int/download/attachments/140385202/lsm_1279l4_0.1x0.1.grb_v4_unpack.nc?version=1&modificationDate=1591979822208&api=v2)
- Forum posts: [https://confluence.ecmwf.int/x/7QEICQ](https://confluence.ecmwf.int/x/7QEICQ); [https://confluence.ecmwf.int/x/sgznDg](https://confluence.ecmwf.int/x/sgznDg)

 ![](https://forum.ecmwf.int/uploads/default/original/1X/5e81260000f133ffb35441b2d545bbed3245d91c.png)