I want to conduct spatial average (for example, global average) on ERA5 parameters (like precipitation), should I consider the different area of each grid cell and apply area weight weighting when conduct conducting spatial average?
For the spatial reference of ERA5, please see this web page: ERA5: What is the spatial reference - Copernicus Knowledge Base - ECMWF Confluence Wiki
If I should apply area weightweighting, how can I calculate the area of each grid cell?
...