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Weather on Earth By: Alwin Wen and Chetan Immanneni

The Atmosphere The atmosphere of Earth are a layer of gases that surround the earth. The atmosphere stops and prevents dangerous gases like radiation from getting into the earth. It also warms the earth due to a greenhouse effect and reduces temperature differences between day and night. The five layers of the atmosphere are called the thermosphere, stratosphere, mesosphere, troposphere, and exosphere. The layer that is closest to the earth and has the air we breath is called the troposphere. The biggest layer and the second highest layer is called the thermosphere. The highest layer is called the exosphere. The stratosphere and mesosphere are the second and third lowest layers, and along with the troposphere are the smallest layers.

Wind Patterns There are five major types of global wind patterns. Polar easterlies - These winds are cool, going to the southernmost tip of the globe. (These winds make the Antarctic continent blistery cold) Polar westerlies – These winds are also cool, supplying the northern part of the globe with cold weather. ( These winds make Greenland, Norway, and Iceland really cold) Westerlies - These winds are located on the horse latitudes ( 30-60) degrees, they bring jet streams to both the North and South America. Trade winds - These are winds that bring hot air to the equator, and make sure other places don't get too much heat. Doldrums - These winds are located near the equator, since warm air is being supplied from the north and south, the winds are very calm, often slowing down or stopping sailboats.

Ocean Currents There are two types of ocean currents; surface currents and deep ocean currents. Surface currents make up of about 10% of all the water in the oceans and happen mostly in the top 400 meters of the ocean. Deep ocean currents make up of about 90% of all the water in the oceans. They move around by forces caused by density and gravity. Ocean currents are caused by two types of forces. The first type is called a primary force. These forces cause the currents to move, and some examples are gravity, winds, and solar heating. Secondary forces influence where the water will go. Near the equator, the water is 8 centimeters higher than the middle latitudes. This cause a small slope that the water wants to flow down.

High Pressure High atmospheric air pressure is caused by the unequal heating of earth's surface. Logically a high pressure area is an area where the relative high atmospheric pressure is greater than it's surrounding area. Some places with extreme amounts of high pressure can cause an anticyclone, which causes storms and high precipitation. High pressure can also cause droughts. The symbol for high pressure is an uppercase H. Although high pressure occurs more during cold seasons, it does little damage to the surrounding area.

Low Pressure Low atmospheric pressure is also caused by the unequal heating of earth's surface. And logically a low pressure area is where he relative low pressure is greater than the surrounding area. Some places with extreme amounts of low pressure can create a cyclone which causes extreme precipitation and sometimes creates storms. The symbol of low pressure is represented with an uppercase L.

Convection Convection is a big mode of heat transfer, called convection heat transfer. Convection currents are currents that bring around heat inside the Earth in the mantle. As the inside gets hotter, the currents move up. The surface is colder than Earth's core, so as the currents reach the surface, they reverse back and go down because of the coolness that makes the currents to go down. Then the cycle repeats, and is what we call convection currents inside Earth. Convection heat transfer is a way where the convection moves fluids. This is usually the largest way of transfer.

Weather Fronts There are three types of fronts: warm fronts, cold fronts, and stationary fronts. Warm Fronts: Warm fronts are fronts that replace colder fronts. These move from southwest to northeast and once a warm front passes through, the air will become warmer and more humid. Cold Fronts: Cold fronts are fronts that replace warmer fronts. These move from northwest to southeast. Once a cold front passes through, the air will becomly colder and drier and the temperature can drop 15 degrees in the first hour of a cold front. Stationary front: Stationary fronts are cases where there are two fronts that meet each other but neither is strong enough to push each other back. Some results of a stationary front include storm trains or clouds. Also, a stationry front can turn into a cold or warm front if the conditions change.

Hurricanes A hurricane is also known as a tropical cyclone is a low pressure system surrounded by the spiral arrangement of warm clouds swirling on the top. The warm clouds on top bring large amounts of rain while the cold swirling winds on the bottom bring harsh winds. The mixture of this brings a lot of destruction and harm in large distances. The main center is called the eye of the storm, the eye can be 1 inch to 1 mile wide. Since the winds are only spinning around the hole this is the safest place to go when a storm arrives. The symbol for a hurricane is represented with a symbol.

Tornados Tornadoes are harsh spinning swirls of air that reach from a thunderstorm to the ground. Warm moist air from the Gulf of Mexico needs to meet cool dry air from Canada. As warm and cold air meet, the atmosphere becomes unstable. Wind direction changes and wind speed gets faster, causing an invisible horizontal spinning effect. Tornadoes appear to look like a funnel shape. There can be many vortices, which are miniature tornadoes that follow a common center. Some can be invisible. Scientists do not know yet how tornados stop. Tornadoes can happen in any time of the year. The peak time for tornadoes to happen in the southern states is from March to May. For the northern states, it is in the summer. Tornadoes are most likely to happen between 3 to 9 PM.

Sun and Sun's Energy The sun is the basic source for all life on earth, it supports plant life and works the water cycle. The sun's energy comes to earth in electromagnetic waves, the term used for sun's energy is called solar radiation. The energy from the sun comes from the gases that heat fuel the sun every single day. Someday the gases might stop and plant life, then the water cycle, and important vitamins for us all will be stopped. Scientists are trying to find an alternative.

Isotherm and Isobar Isotherms are contour lines that connect points on a weather map. Points on an isotherm all have the same temperature. Isotherms that measure at 0 degrees Celsius are called freezing levels. Isotherms are easily found on weather maps as curved lines. Isobars are lines of the same pressure on a map. Isobars join place of the same atmospheric pressure. Isobars are used in television news reporting, though are used in weather news more in Europe than in the United States.

Types of Precipitation There are four main types of precipitation. Rain - Rain is the most common type of precipitation. It is pretty much water vapor that evaporates into the sky then condenses and falls as precipitation. Snow - Snow is water vapor that is frozen into ice crystals. It can be used to create snowmen and snowballs and can pile on top of more snow to create white layers. Hail - Hail is the solid form of water vapor. It can be as small as a fingernail but as large as a rock. Hail can break glass as well. Sleet - Sleet is rain that contains some ice. Sleet is the least common type of precipitation, and is hard to find. However, sleet can make roads very slippery.

Types of Clouds There are three main types of clouds: Cumulus: These clouds are the most common types of clouds. They look like cotton balls, there are also many types of cumulus clouds, cumulonimbus, stratocumulus, etc. They usually bring rain. Stratus: These clouds are common but not as common as the cumulus clouds. They look like a thick layer of fog. They also bring fog and precipitation! Cirrus: These are the most rarest types of clouds. They look like wisps. They don't bring any precipitation. And the cloud type has no basic variations other than itself.

Dew Point Dew point has to deal with the relative humidity. It is also a water to air saturation temperature. It is pretty much the temperature where the atmospheric temperature causes water droplets to condense and dew is able to be formed. A high relative humidity shows that the dew point is closer to the current air temperature. A low relative humidity shows that the dew point is farther. If it is very moist in the air, the body's perspiration will not evaporate, resulting in an uncomfortable feeling.

How scientists get and use satellite images Satellite images are used a lot by scientists to observe and watch planets and moons in the galaxy. They send satellite robots in space to get pictures and bring back to Earth. Scientists use these images to sometimes try and think of how the planets and moons in space will move. This is not always easy to do. Most people cannot do this because they are not patient enough to do so.

To the left is a picture of a satellite that is spinning around Earth. It takes pictures and sends them back down to Earth where scientists study and decide on what these pictures can mean.

Weather Map

Meteorological Instruments used by scientists Barometer- A tool used to measure air pressure Thermometer- A tool used to measure temperature Anemometer- A tool used to measure wind speed Compass- A tool used to measure directions Wind vane- A tool used to measure wind direction Hygrometer- A tool used to measure humidity Rain Gauge- A tool used to measure precipitation( not only rain) Evaporimeter- A tool that measures the rate of evaporation There are many more instruments that are used by scientists, but these are the basic ones.

T-Chart Alwin The Atmosphere Ocean Currents Convection Weather Fronts Tornados Isotherm and Isobar Types of Precipitation Dew Point How scientists use satellite images Graphics

Chetan .Weather map .High Pressure .Low pressure .Wind patterns .Meteorological instruments .Sun and sun's energy .Types of clouds .Title Slide .Hurricanes

Period 3, Alwin Wen and Chetan Immanneni, Weather on Earth