Essay about ATSC 201

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Pages: 7

Ch1 pg 1 - 22
1. Convert between any timezone and UTC.
- Coordinated Universal Time (UTC) is the time zone at the prime meridian.

2. Plot the average variation of air pressure, temperature, and density with altitude, and explain why they vary that way.
- (In fluids) pressure force is isotropic, at any point it pushes with the same force in all directions. Atmospheric pressure that you measure at any altitude is caused by the weight of all air molecules above you. As you travel higher in atmosphere there are fewer molecules still above you; Pressure decrease with height. Pressure can compress the air causing higher density. Compression is greatest where pressure is greatest, the bottom of the atmosphere.
As a result of more molecules being squeezed into a small space near the bottom than near a top, ambient pressure decreases faster near the ground than at higher altitudes. Pressure change is approximately exponential with height, z. Pressure decreases slower with height in warmer air because the molecules are further apart.

3. Contrast geopotential height with geometric height. - Geopotential height, H, is defined to compensate for the decrease of gravitational acceleration magnitude |g| above Earth’s surface. It is defined as the work per unit mass to lift an object against the pull of gravity, divided by the gravitational acceleration value for sea level. Geopotential is defined as the work done against gravity to lift 1 kg of mass from sea level up to height H. It has units of m2 s–2.
- (an air parcel - a group of air molecules moving together) raised to Geometric height, z, would have the same potential energy as if lifted only to height (H) under constant gravitational acceleration.
- By using H instead of z, you can use |g| = 9.8 m s–2 as a constant in your equations, even though in reality it decreases slightly with altitude. - The difference (z – H) between geometric and geopotential height increases from 0 to 16 m as height increases from 0 to 10 km above sea level.
Basic Thermo & Hydrostatic Relationships
1. Describe the physical concepts behind the equations of state, hydrostatic, and hypsometric, and be able to use them.
- The relationship between pressure, density, and temperature is called the Equation of State. High humidity reduces the density of the air so much that it acts like dry air


Hydrostatic is used because it describes a stationary
(static) balance in a fluid (hydro) between pressure pushing up and gravity pulling down. The negative sign indicates that pressure decreases as height increases. This equilibrium is valid for most weather situations, except for vigorous storms with large vertical velocities.


When the ideal gas law and the hydrostatic equation are combined, the result is an equation called the hypsometric

equation. This allows you to calculate how pressure varies with height in an atmosphere of arbitrary temperature profile: 2. Relate the "iso..." names to the atmospheric processes that they represent.
3. Explain what the virtual temperature represents, & be able to compute it and use it.
- Moist air of temperature T behaves as dry air with temperature Tv . Tv is greater than T because water vapor is less dense than dry air, and thus moist air acts like warmer dry air. Virtual temperature Tv can be defined to include the effects of water vapor.

Ch14 pg 481 - 487, 492 - 495
Thunderstorm Characteristics & Types (including
1. Visually recognize thunderstorms and identify their cloud components.
2. Describe the stages in evolution of a thunderstorm cell.
3. Compare & contrast basic storms vs. supercell storms. 4. Explain how different types of supercell storms work.
Ch14 pg 488 - 492
Ch8 pg 219, 240 - 244, 247 - 251, 253 - 254
Thunderstorm Mesoscale Convective Systems (MCS), Radar Fundamentals & Storm
Chasing Tips
1. Compare and contrast MCS storms with other thunderstorm types.
2. Summarize how a weather radar operates.
3. Interpret radar reflectivity info to…