this week we are studying Temperature in chapter 3 and Humidity in chapter 4. You will be differentiating between absolute humidity, mixing ratio and relative humidity. Which one do you think is more accurate way to measure actual water vapor content in the air? Which one measures how close air is to saturation (equilibrium between evaporation and condensation). What kind of air produces severe weather? Stable or unstable?

Let's review something from chapter 1. Environmental lapse rate (ELR) is the rate at which temperature decreases in the troposphere. It is about 6.5 degrees C per kilometer of altitude. This is usually measured by a radiosonde and does change often. ELR is the temperature of the air at different heights.

In chapter 4 you will learn two more rates at which temperature change. Dry adiabatic rate (DAR) and wet adiabatic rate (WAR) are the rates at which the temperature of a parcel of air changes adiabatically (due to the parcel expanding as it rises) when that parcel is unsaturated (DAR) or saturated (WAR). DAR is 10 degrees C per km and WAR is 5 to 9 degrees C per km. Make sure you understand the difference between these rates.