[Updraft]

I have the arduino's programation code for this sensor, but with this code I can only get a real(absolute) atmospheric pressure according my altitude, and not the sea level atmospheric pressure.

Hi,
You have to recalculate the pressure according to the formula:
Prel = Pabs + h/8.3

Prel is relative pressure (recalculating to the sea level) [hPa]
Pabs is absolute pressure at the messurement place/site [hPa]
h is altitude (height above sea level) [m]

This applies with sufficient accuracy to about 1000 m above sea level.

Thank you so much for the help and the for the tip . I'm going to try to implement this formula in the arduino's programming code of the BMP280.

As soon as I get results, I'll give you feedback.

Best regards, 
Lourenço V.