Cams irradiation time series single point product vs. gridded big difference

Datasets and Usage CAMS - Datasets and Usage
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1

I have a problem with the gridded cams irradiation dataset. If I compare the values e.g. for lat=48.25, lon=12.25 (which should be exactly in the gridded dataset) with the single point time series product , I get for the yearly sum of GHI values in 2019:

gridded GHI data for point 48.25/12.25: 1.064 kWh/m2 (full year 2019)
direct single point time series via cams-API 48.25/12.15: 1267 kWh/m2 (full year 2019)

How can this difference explained? The values of the gridded timeseries appear to be generally (I compared different points in Europe) ~10-15% too low.

I would appreciate any help or support (Maybe I did something wrong?) - thank you.

K. Schulze

2

This difference can be explained by the way CAMS works. The single point time-series product is recalculated on the fly and includes all updates that have been applied to the retrieval algorithm up to now, even when downloading data from the past, i.e. the new algorithm is applied retrospectively. The gridded dataset is thus outdated, or at least the data is “frozen” in with the retrieval algorithm from that time (in your case 2019).