Notes for METR 356

Lyndsay Hunter & Louie Abad

September 15, 2004

Condensation:

W e went over condensation. We talked about how the water vapor on our planet is the only gas component of our atmosphere that can condense naturally. When the atmosphere is cool enough, the water vapor molecules, which are randomly bouncing around all the time just like all the other molecules are, when they happen to touch each other, they will stick. Because of the chemical composition of the water vapor, small droplets of water result and the collection of them represent what we call clouds.

Satellite Pictures:

Understanding condensation is important in understanding satellite images, as they view the collections of water vapor molecules around our earth. We talked about how to look these clouds in a satellite picture. One of the properties of the droplets is the ability to reflect a lot of visible lights. So if you were in a satellite, you can actually see the clouds because of the reflective lights that get bounced back to the satellite. Since cumulus clouds are very thick, they reflect a lot of the lights so that in black and white the cloud will appear bright white. Stratus clouds, layer of clouds which are not very thick and don't reflect a lot of the lights and because of that they will appear grayish on a satellite picture. We also mentioned about cirrus clouds. These clouds are also high clouds but not thick clouds but they are found near the top of cumulonimbus clouds. They are feathery looking clouds that are made of ice crystals.

Clouds:

We also differentiated the difference between the cumulus and stratus clouds. They represent the extremes in the atmosphere. One produces a lot of rain and the other one does not produce any rain at all. It turns out that the thicker the cloud is the more likely it produces heavy rainfall. The smaller the cloud in thickness like the stratus cloud is less likely to produce heavy rainfall or any rainfall at all, most likely just a little drizzle.

Infrared Images:

Infrared image is a different kind of image in which the sensor detects energy a person cannot see with his or her eyes but the sensor can. The sensor is designed so it detects or senses the energy or temperature from objects. Different temperatures of the clouds are color coded from its warmest to coldest temperature.

Longitude:

We talked about the lines of longitude. These are the lines in the globe the run north and south. They can also be referred to as meridian lines.

Severe Thunderstorms

Severe, and even hazardous thunderstorms are constituted by hail (3/4" in diameter) , strong winds (57mph or more) , and tornadoes (whirlwind attach to the thunderstorm,even the weakest with winds about 40-70 mph are considered a danger to the public). Generally, all thunderstorms are most severe near the middle or the eye of the storm. Usually a thunderstorms' most threatening feature is the wind.

Frances:

We looked at an intensity map of hurricane Frances. We talked about the different symbols. When the symbol is filled in black and has wings it is a hurricane, when it's not filled in and has wings it is a tropical storm, and when it is not filled in and does not have wings it is a tropical depression. (The features of severe thunderstorms are what help to rank these storms.) We looked at the expected future track of the hurricane on the map.

NOTE: All storm systems rotate. In northern hemisphere they rotate counterclockwise.

Dew Point Temperature:

We talked about the dew point temperature. It is the measure of how much the air must chill in order for the water vapor molecules to condense and cause 100% humidity. The higher the dew point temperature, the greater the amount of water vapor present. Relative humidity is the difference between the actual temperature and the dew point temperature. The smaller the difference between the actual and dew point temperatures, the higher the relative humidity, or the closer the atmosphere is to a state in which water vapor would condense. This is very important for the meteorologist to know. Having this plotted on the map is very important.