better understanding of power correction

when considering mass of air and air density along with existing altitude , what standard condition for tuning?

How to determine the specific air temp and air Psi for a given location or altitude?

You can't say that a given altitude will offer a specific temperature and pressure since this varies day to day depending on ambient conditions. For the same reason the air pressure at sea level isn't always the standard of 101.3 kPa. As a general guide, air temperature decreases by 2 degrees C per 1000 feet and air pressure reduces by 1 kPa for each 300 foot increase in altitude. I hope that helps?