weather By: Jimmy Burgard
What is evaporation? • evaporation is the process by which water changes from a liquid to a gas or vapor. • if you put an ice cube on the ground in the summer it will melt and then it will evaporate. • The higher temperature the more evaporation 1.
What is condensation? • Condensation is the accumulation of water vapor changing to liquid water onto a surface. • Condensation occurs when • the temperature of any surface falls below • the dew point. 2.
What is precipitation? • Precipitation is also part of the hydrologic cycle. • You’ve already learned that the main forms of precipitation are rain, hail, snow, sleet, and freezing rain. 3. http://ellerbruch.nmu.edu/classes/cs255f02/cs255students/abarker/P4/watercycle.html
What causes rain? • Warm air can hold more water than cool air, so when the warmer air is cooled the moisture condenses to liquid - and it rains. 4.
Cirrus clouds • cirrus clouds are the highest in elevation. • Form above 20,000 feet. • the temperature at that elevation is so cold that cirrus clouds are usually composed of ice crystals. • This can only happen when the temperatures reach below -38 degrees Celsius. 5. http://ellerbruch.nmu.edu/classes/cs255f02/cs255students/abarker/P4/cirrus.html
Cumulus clouds • cumulus clouds are probably the most recogonized clouds out of all of the cloud types. • cumulus clouds appear so fluffy because bubbles of air called thermals, linger in the cloud making it have this kind of look. • cumulus clouds form below 6,000 feet. • But in some extreme cases they can be in altitudes as high as 39,000 feet. 6. http://ellerbruch.nmu.edu/classes/cs255f02/cs255students/abarker/P4/cumulus.html
Stratus clouds • stratus clouds are uniformed layered clouds that are below 6,000 feet. • They can form only a few hundred feet above ground. • they are shallow but cover a large area and they can bring precipitation. • stratus clouds are more known for drizzle than for precipitation 7.
9. • spring
10. • summer
11. • Fall
12. • winter
Rain • rain occurs when warm air rises, cools, condenses. • the dew point is reached, the air becomes saturated and water droplets fall from the clouds. 14.
Snow • snow occurs when the air temperature is below freezing. • water droplets freeze and fall as snow flakes. 15.
Sleet • sleet forms when the water droplets fall and freeze before they reach the surface of the earth. • the temperature of the clouds are above freezing. • the temperature close to the earth surface is below freezing. 16.
Hail • hail forms in high level clouds where the temperature is below freezing. • the water droplets in the clouds freezes. • the surface temperature of the earth is above freezing. 17.
Air masses Type of land air symbol Continental Form over land Dry air c maritime Form over water / ocean Wet air m polar Form in the north Cold air P Tropical Form in the south Warm air T arctic A Very cold 18.
High + low pressure Type of pressure type of weather High pressure Nice weather Low pressure Worse weather 19.
Front- A boundary between two different air masses is called a front. Atmospheric pressure is determined by the temperature and density of the air and the amount of water vapor in it. Pressure- Precipitation- Storms and precipitation occur at fronts. Temp- Fronts usually bring a chance in temperature. Direction- Fronts always bring a chance in wind direction. Air mass- A air mass is a large body of air with the same properties as earth’s surface under it. Isotherm- A line connecting points of equal temperature is a isotherm. 20. Station model- A station model shows the weather conditions at one specific location.
What is the dew point? The temperature at which condensation forms from saturated air. What is sleet? Rain drops that pass through a layer of freezing air near Earth’s surface forming pellets. What is fog? A stratus cloud that forms near the ground. What is humidity? The amount of water vapor in the air. What is wind? Air moving in a specific direction. What is relative humidity? The measurement of the amount of water vapor in the air compared to the amount needed for saturation at a specific temperature. What is weather? A description of the current state of the atmosphere. What is temperature? A measure of the average of motion of molecules. What are clouds? Objects that form as warm air rises, expands, and then it cools. What are types of precipitation? Rain, snow, sleet, and hail. 21. What is caused by the interaction of air, water, and sun? The weather.