Transcript Weather PPT
Weather Systems & Cloud Types The Real Weather Forecaster Air Masses •Bodies of air that bring distinctive weather features to the country. •A mass of air in air that is very uniform in temperature, pressure, and humidity. •Polar = cold •Tropical = warm •Maritime = moist Continental = dry Air Masses •May cover several millions of square kilometers and extend vertically throughout the troposphere Layers of the Atmosphere Wind energy starts with the sun Weather Map: Fronts, Systems, Jet stream Weather Fronts A front is the transition zone between two air masses of different density. Fronts extend not only in the horizontal direction, but in the vertical as well. Cold Front & Air Masses Cold Front on a Weather Map Warm Front on a Weather Map Occluded (Stationary) Fronts Pressure of Air Masses Force Weight Pr essure Area Area •Air Pressure = weight of air acting on an area •Warm Air has more KE and spreads out more. Therefore, it’s less dense and has less weight . This means less pressure. Warm Air Masses are less dense and have Lower Pressure Pressure Systems • Uneven heating of the Earth’s surface causes differences in air pressure • Warm Air Low Pressure System • Cold Air High Pressure System Wind Patterns • Air flows from areas of high pressure into those of low pressure • Northern Hemisphere: air flow from areas of high to low pressure is deflected to the right; producing a clockwise circulation around an area of High pressure. • Counter-clockwise circulation around an area of Low pressure. Wind Circulation Patterns Global Wind Patterns Weather Forecasting • Tools Used: • • • • • Thermometer (temperature) Barometer (pressure) Hygrometer (humidity) Radar (storm & cloud movement) Satellite imagery (storm & cloud movement) • National Weather Service Boise Site: • http://www.wrh.noaa.gov/boi/ • Weather Channel Site: • http://www.weather.com/ Weather Maps Climate • Average of all weather conditions in area over a long time • Ex: temperature, precipitation • Climate is cyclically influenced by ocean currents & temperatures • El Niño & La Niña • These variations alter: • surface wind • surface ocean temperatures • deep ocean temperatures Climate Cycles • Caused by variations in ocean currents & temperatures • Cycles occur every 3-7 years • El Niño: characterized by unusually warm ocean temperatures in the Equatorial Pacific • La Niña: characterized by unusually cold ocean temperatures in the Equatorial Pacific Normal vs. El Niño Ocean Temperatures Unusually warm ocean temperatures in the Equatorial Pacific Winters are warmer than normal in the Northern States & cooler than normal in the Southern States Is Global Warming Real? YES! – The only possible question is: Did Mankind Accelerate it?” Normal vs. La Niña Ocean Temperatures Unusually cold ocean temperatures in the Equatorial Pacific Winters are cooler than normal in the Northwest & warmer than normal in the Southeast Long Term El Nino due to global Warming? Cloud Characterization •Clouds are characterized by: 1. Height above the ground a) Cirro b) Alto c) Nimbo 2. Type of cloud a) Cirrus b) Cumulus c) Stratus – any cloud type can form layers Cloud Levels & Types Cloud Levels & Types Cloud Levels & Types