Transcript Weather_000
Weather Learning Goal: Comprehend the 3 ways energy moves through the earth’s atmosphere. Energy of the Atmosphere Sun – 98% of the energy in Earth’s atmosphere comes from the sun in the form of electromagnetic waves. Radiation – is the direct transfer of energy by electromagnetic waves. -visible light most - infrared -ultraviolet Blue sky – is the product of the reflection and scattering of light in all directions causing the short wavelengths of blue and violet to appear. Dusk and Dawn – the scattering of longer wavelengths (red and orange) due to light traveling through more atmosphere. Mid-day Dusk/dawn Energy at the surface 1. Absorbed by earth 2. Reflected back to atmosphere 3. Absorbed by the clouds and gases in atmosphere. Green house effect – is when energy is absorbed by water vapor, CO2, methane, and other gases in the air, causing a warm “blanket” to form in the atmosphere. Temperature Thermal energy – the total energy of motion in the molecules of a substance. Temperature – is the average amount of energy of motion of each molecule of a substance, thus the measure of how hot or cold a substance is. Thermometer – a thin glass tube with a bulb on one end that contains a liquid (colored alcohol) ---- temp----when a liquid is heated up it will expand! This expansion is restricted to going only two directions in a thermometer, UP or Down! When it rises it indicates more energy in the liquid molecules and causing the liquid to expand up. When heat (energy) is lost the molecules will come closer together taking up less space and indicating a lower temp. Heat Transfer 3 types 1. radiation – the direct transfer of energy by electromagnetic waves. 2. Conduction – the direct transfer of heat from one substance to another substance that it is touching. 3. Convection – The transfer of heat by the movement of a fluid. Pg. 51 radiation eyr Winds Wind – is the horizontal movement of air from an area of high pressure to an area of lower pressure. - pressure differences are caused by an unequal heating of the atmosph. - cold dense air sinks and warm air rises causing a movement of air (wind) high pressure vs. low pressure. Anemometer – measures wind speed. Wind chill is the cooling of warm blooded mammals do to heat loss from wind. Wind direction – Named (west wind) by the direction is coming from. So, a west wind would be coming from the west and blowing toward the east. Local wind – winds that blow over short distances. Ste. Gen to Cape or smaller, do to unequal heating of surface of Earth. Sea breeze – wind blowing inland from the sea. Earth heats up quicker less pressure than air over water more pressure. Day time. Land breeze – wind blowing out to sea from the land, due to opposite of sea breeze. Night time Monsoons – sea and land breezes over a large region that change direction with the seasons. Global winds – (created by unequal heating) winds that blow steadily from specific directions over long distances. The movement of air from the equator to the poles as a result of convection is a global wind. See pg 59. Coriolis Effect – The way Earth’s rotation makes winds curve. http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/f w/gifs/coriolis.mpg Jet stream – A high level stream of fast moving air. At altitudes of 6 miles high and at speeds of 180km to 350km. El Nino • El Nino - (El Nee-nyo) is the warming of water in the Pacific Ocean. • Rain and flooding along the Pacific Coast • Warm water disrupts the food chain of fish, birds, and sea mammals. • Tornadoes and thunderstorms in the southern US • Fewer than normal hurricanes in the Atlantic La Nina • La Nina - (Lah Nee-Nyah) is the cooling of water in the Pacific Ocean. • Snow and rain on the west coast • Unusually cold weather in Alaska • Unusually warm weather in the rest of the USA • Drought in the southwest • Higher than normal number of hurricanes in the Atlantic • http://esminfo.prenhall.com/science/geoanimatio ns/animations/26_NinoNina.html Water Cycle • Amount of water remains the same as it moves through the cycle • Fresh water is limited • All living organisms need liquid water • Earth’s water is continually being recycled Evaporation – process by which water molecules escape into the air by radiant energy from the sun changing water into a gas (water vapor). Relative humidity – the percentage of moisture the air holds relative to the amount it could hold at a particular temperature. Psychrometer – instrument used to measure the amount of R. humidity in the air. It consist of two thermometers, one wet and one dry. Cloud formation Clouds form when water vapor in the air becomes liquid water or ice crystals. Water vapor changing into a liquid----CONDENSATION The temperature at which condensation begins is called dew point. Cumulonimbus – Thunderstorm clouds that produce severe weather, tornadoes, hail, strong winds. Have anvil shape to top of cloud. Clouds Cumulus – usually indicate fair weather. 2 to 7 miles in the sky (cotton balls). Cirrus – Feathery or fibrous in appearance. Very high altitudes usually between 6 and 12 kilometers. Indicate the onset of rain or snow in a few hours. Stratus clouds – smooth gray clouds that cover the whole sky and block out the sun are called stratus clouds. These clouds produce steady, light precipitation. Precipitation – Water vapor that condenses and forms clouds that can fall to the Earth as rain, sleet, snow, freezing rain or hail. sleet – water droplet that freezes when it falls through cold air. (winter) snow – forms when water vapor changes directly to a solid. Hail – ice balls that fall after water is frozen in the air then pushed further up and collects more water and freezes again, over and over until it becomes to heavy to stay suspended in the air. The stronger the uplift the larger the hail stone. (summer) Freezing rain – rain that freezes upon contact with the ground. • Isobar A line on a weather map connecting places that have the same air pressure. high-pressure system A generally calm and clear weather system that occurs when air sinks down in a highpressure center and spreads out toward areas of lower pressure as it nears the ground. (More dense cold air) low-pressure system A large and often stormy weather system that occurs when air moves around and into to a low-pressure center, then moves up to higher altitudes. (Less Dense Warm Air) Storms • Caused by: • Changes in temperature & drop in barometric pressure • Ex: Hurricanes are a low pressure mass over tropical (warm) water Weather Fronts • Air mass-a huge body of air that has similar temperature, humidity, and air pressure • Front-the area where two air masses meet and do not mix • Dense,cold air moves underneath the less dense warm air, pushing it up Front Types • Cold front-rapidly moving cold air mass that runs into a slowly moving warm air mass • Move quickly, causing violent storms • Warm front- warm air that collides with cold air • Moves slowly, causing fog or rain for days, and in the winter, snow Cold Front (More Dense cold Air) Cold Front Warm Front (Less Dense Warm Air) Warm Front Stationary Front Stationary Front Weather Forecasting • Meteorologists-scientists who study weather and try to predict it • Forecasting has greatly improved due to computer technology • Collecting weather data has improved because of satellites and balloons Seasons and Climate • Earth has seasons because Earth’s axis tilted as it moves around the sun • Winter-axis tilted away from sun resulting in shorter days and indirect rays • Summer-axis tilted toward sun resulting in longer days and direct rays Climate • • • • • Caused by: Altitude Latitude Mountain barriers Proximity (closeness) to oceans • Climate is classified by precipitation and temperature based on these factors