2. (a) After the parcel of air has descended down the lee side of the
mountain to sea level, what is the temperature of the parcel?
(b) Why is the parcel now warmer than it was at sea level on the windward side (what
is the source of the heat energy)?
3. (a) On the windward side of the mountain, is the relative humidity of the parcel increasing or decreasing as it rises from sea level to 3000 meters?
(b) Why?
4. (a) On the lee side of the mountain, is the relative humidity of the parcel increasing or decreasing as it descends from 6000 feet to sea level?
b) Why?
2. (a) The temperature of the parcel after it has descended down the lee side of the mountain to sea level will depend on the local climate and weather conditions.
(b) The source of the heat energy is the compression of the air as it descends down the mountain. As the air is compressed, it is heated up due to the increase in pressure.
3. (a) On the windward side of the mountain, the relative humidity of the parcel is decreasing as it rises from sea level to 3000 meters.
(b) This is because as the air rises, it expands and cools, causing the relative humidity to decrease.
4. (a) On the lee side of the mountain, the relative humidity of the parcel is increasing as it descends from 6000 feet to sea level.
(b) This is because as the air descends, it is compressed and heated up, causing the relative humidity to increase.
2. (a) To determine the temperature of the parcel after it has descended down the lee side of the mountain to sea level, we need to understand the concept of adiabatic heating and cooling. As an air parcel rises, it expands due to decreasing atmospheric pressure. This expansion leads to adiabatic cooling, which means the temperature of the parcel decreases. Conversely, as an air parcel descends, it compresses due to increasing atmospheric pressure. This compression leads to adiabatic heating, causing the temperature of the parcel to increase.
Therefore, when the parcel of air descends down the lee side of the mountain to sea level, it will experience adiabatic heating. Consequently, the temperature of the parcel will be warmer than it was at sea level on the windward side.
(b) The source of the heat energy that causes the parcel to become warmer as it descends on the lee side of the mountain is compression. As explained earlier, as the parcel descends, it experiences higher atmospheric pressure, which compresses the air molecules. This compression increases the molecular motion and kinetic energy, leading to an increase in temperature. So, the compression of the descending air parcel itself is the source of the heat energy.
3. (a) On the windward side of the mountain, the relative humidity of the parcel generally decreases as it rises from sea level to 3000 meters.
(b) The reason behind this decrease in relative humidity is primarily reginal adiabatic cooling. As the parcel rises, it expands due to lower atmospheric pressure, resulting in adiabatic cooling. This cooling causes the air to reach its dew point temperature, at which it becomes saturated. When the air is saturated, it cannot hold as much moisture, and condensation occurs, forming clouds and precipitation. Therefore, as the parcel rises and cools, the moisture condenses out, reducing the relative humidity.
4. (a) On the lee side of the mountain, the relative humidity of the parcel generally increases as it descends from 6000 feet to sea level.
(b) The reason for this increase in relative humidity is primarily due to the process of adiabatic warming and evaporation. As the parcel descends on the lee side, it experiences adiabatic compression, which leads to adiabatic warming. The increased temperature of the descending air causes the water molecules to gain more kinetic energy, promoting evaporation. As more water molecules evaporate, the absolute humidity increases, which, in turn, increases the relative humidity. Hence, the relative humidity of the parcel tends to increase as it descends on the lee side of the mountain.
2. (a) After the parcel of air has descended down the lee side of the mountain to sea level, the temperature of the parcel will have increased.
(b) The parcel is warmer than it was at sea level on the windward side due to the process of adiabatic compression. As the air descends, it experiences higher pressure, which compresses the air molecules closer together. This compression increases the temperature of the air parcel.
3. (a) On the windward side of the mountain, the relative humidity of the parcel is generally decreasing as it rises from sea level to 3000 meters.
(b) The decrease in relative humidity is primarily caused by adiabatic expansion. As the air rises, it experiences lower pressure, causing the air molecules to spread out. This expansion leads to a decrease in temperature, and since cooler air can hold less moisture, the relative humidity decreases.
4. (a) On the lee side of the mountain, the relative humidity of the parcel is generally increasing as it descends from 6000 feet to sea level.
(b) The increase in relative humidity is due to adiabatic compression. As the air descends, it experiences higher pressure, causing the air molecules to compress together. This compression increases the temperature of the air parcel, and since warmer air can hold more moisture, the relative humidity increases.