REGENTS EARTH SCIENCE
Topic 6A Objectives
Meteorology
1. Determine the characteristic of the layers of the Earth's atmosphere using the ESRT.
The chart they need is on page 15 of the ESRT.*Page 15 ESRT* An example of the type of question they could be asked is: What is the temperature of the atmosphere at 50 miles? = -90oC.
2. Using the ESRT make conversions between the three temperature scales.
The chart they need is on page 13 of the ESRT.*Page 13 ESRT* An example of a possible question is: What is 10oC in Fahrenheit? = 50oF
3. Distinguish the difference between the function of a wind vane and an anemometer.
Wind vane determines wind direction. Winds are named by where the wind is coming from.
Anemometer determines wind velocity.
4 a. Define dew point:
The temperature at which the air becomes saturated with water.
b. Using the ESRT and given the wet-bulb and dry-bulb temperatures, determine the dew point temperature.
The chart they need is on the top of page 12 of the ESRT.*Page 12 ESRT * An example of the type of question they would have to answer is: If the air temperature (dry-bulb temperature) is 16oC, and the wet-bulb temperature is 10oC, what is the dew point. To use the chart you need to find the difference between the dry-bulb and wet-bulb. For this problem that is 6oC. Find this number along the top of the chart. Then find the dry-bulb temperature along the left-hand side of the chart. Where the row and column meet is your answer. 4oC.
5 a. Define relative humidity:
Relative humidity is a comparison between how much water vapor is in the air to how much water vapor the air could hold
b. Using the ESRT and given the dry-bulb and wet-bulb temperatures, determine the percent of relative humidity.
The chart they need is on the bottom of page 12 of the ESRT.* Page 12 ESRT * The chart works exactly the same way as the dew point chart. If the dry-bulb temperature was 20oC and the wet-bulb temperature was 15oC, the relative humidity would be 58%.
6 a. Define air pressure:
The weight of the air per unit area.
b. Given a barometric chart determine the air pressure to the nearest hundredth of an inch.
They have a work sheet covering this objective.
7. Describe the relationship between relative humidity and air pressure.
As relative humidity increases air pressure decreases.
8. Explain how changes in air temperature relate to changes in air pressure.
As air temperature increases air pressure decreases
9. Describe the effect air temperature has on the air's capacity to hold water.
As air temperature increases the amount of water vapor the air can hold increases.
10 a. Define adiabatic temperature change:
This is a temperature change caused by a change in pressure. As pressure increases air temperature increases.
b. Describe the effects of a mountain range on creating an adiabatic temperature change.
As air rises on the windward side of a mountain air pressure decreases. This allows the air to expand causing it to cool. If it cools to the dew point clouds will form and it will rain. As the air travels down the mountain on the leeward side air pressure will increase. This causes the air to be compressed and increases the air temperature. Now the separation between the air temperature and the dew point increases causing the air to become dry.
11. Explain 3 conditions that lead to the formation of a cloud:
1) There must be water in the air.
2) The dew point must be equal to the air temperature.
3) There must be a surface in the air for the condensation to form on.
12. Using the ESRT and given the surface air temperature and dew point temperature, determine the altitude of the cloud base.
They need the chart on page 13 of the ESRT.* Page 13 ESRT * The solid lines on the chart are for the decrease in the dry-bulb temperature that occurs as air rises. The dashed lines are for the decrease in dew-point temperature that occurs as air rises. Follow the lines for the temperatures given in the problem, up from the bottom of the chart until they intersect. Go to the right or left of the intersection point to the scales on the sides of the chart and it will tell you the base height of a cloud in km. For example if the dry-bulb temperature was 20oC and the dew point temperature was 10oC the cloud base height would be 1.3km
13 a. Explain, which condition of cloud formation, may result in the occurrence of precipitation.
For precipitation to occur enough cloud droplets need to join together to over come the upward movement of air.
b. Identify one effect that precipitation has on the atmosphere.
Precipitation removes pollution from the air.
14. Identify the relationship between dew point and air temperature, which increases the probability of precipitation.
The closer the dew point is to the air temperature the greater the probability of precipitation.
