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Pressure assimilation from SYNOP to Little_R

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I'am currently writing a code to transform SYNOP data to Little R format, guided by the tutorial on: .

I have a question regarding the pressure assimilation. As you probably know, most SYNOP codes have 2 fields for pressure: 3pppp and 4PPPP, which correspond to Station Level Pressure and Sea Level Pressure accordingly.

In the header record for Little R there are a few fields, relevant to pressure or elevation, but if I understood the notes on the optional and unused fields correctly, none of them are used in the assimilation for FM-12 SYNOP.

In the data record, there are Pressure [Pa] and Height [m] fields. Is it correct to put the Station Pressure in the Pressure [Pa] field and the Station Elevation (which is the same as topography) in the Height [m] field?

Is there any way I can use the Sea Level Pressure, provided by the SYNOP, rather than the Station Pressure?