During hot, dry Santa Ana events, winds blow from the high desert down into the Los Angeles basin. High desert Altitude = 3500m Temperature = 5 °C Relative humidity = 70% Los Angeles Altitude = 45 m Temperature = ? °C Relative humidity = ? % a) Using the information on the diagram above, as well as your knowledge about lapse rates, what is the temperature of the air when it reaches Los Angeles? (2)

b)As the air sinks down, it is channeled through narrow valleys and so speeds up. In the desert the wind blows at about 5 miles per hour across an area of 100 square miles (width x height in the atmosphere). It is then squeezed into an area of just 20 square miles as it blows through narrow valleys in the mountains around Los Angeles. Assume that airflow must stay constant, what would the velocity of the air be? (2)

Airflow = area * velocity

c) Vegetation has to be heated up to 330 ^oC in order to ignite. Can you explain, using the physics we learned in class, why vegetation that contains more water does not ignite as easily as dry/dead vegetation? (2)