Environmental lapse rate average is rounded to 2 degrees celsius per 1000 ft.(Note that environmental lapse rate varies through the day).What about parcel of air lapse rate.? Dry lapse rate is a constant while saturated lapse rate varies based on water vapor in the first place. Do pilots flying big airlines care about these values? Apart from being able to calculate cumulus cloud base from Temperature and dew point... I also heard of something called CAPE seen in Skew T Log P diagram. Do pilots practically flying big planes worry about these? Or is technology different now a days that pilots do not need to care about dry and saturated lapse rate and environmental one...
1 Answer
Yes, they care about weather conditions at various altitudes but do not need to calculate them because the information is already available in the METAR reports. Reading METARs, weather radar, and other forecasting information is an important part of pre-flight planning.
While dry lapse rates are more or less constant, warmer air has a much higher water carrying capacity than cold air, hence, the moist lapse rate can be much lower because more latent heat is released per parcel of air as more water vapor condenses. Moist lapse rate is dependent on temperature and relative humidity.