Weather All Around Us Gaby and McKenna
Table of Contents 1...Sun and Sun's Energy & Convection 2...Atmosphere 3...Ocean Currents 5...Wind Currents 7...Instruments and Images 10...Weather Maps 11...Isotherm and Isobars 13...High & Low Pressure 15...Dew Point 16...Types of Clouds 17...Types of Perception 18...Fronts 20...Hurricanes 22...Tornadoes 23...T-Chart
Sun's Energy & Convection The sun is a big, bright star that all of the planets circle around. The sun's light and warmth, or energy, travels to Earth. It is the reason why you are warm outside and for the brightness of daytime. The light and warmth of the sun travel to the earth in forms of electromagnetic waves. The sun is also the cause for wind and ocean currents. The energy is the cause of convection, or the heat transferred through gasses or liquids, creating uneven cooling in the atmosphere and oceans. This unequal heating in the atmosphere creates wind, and the uneven heating of the ocean creates ocean currents. 1
Atmosphere Earth's atmosphere is made of four layers. The layer closest to the Earth is the Troposphere, which is 0-10 km thick. The next layer which is 10-25 km thick is the Stratosphere. Next is the Mesosphere, containing the ozone layer. It has a width of 25-100 km. The highest and thickest layer, 100-400 km wide, is the Lomosphere. In the Lomosphere, the Northern Lights appear and small meteorites burn up. Nitrogen is the most abundant resource that can be found in the atmosphere.
2
Ocean Currents In the oceans around the world, there are different currents in the large bodies of water. Currents are the movement of water, almost like a river within the ocean. Currents can reach up to several hundred meters deep, and are caused by the different temperatures, different salinity, or how salty the water is, and by winds. Most of the things we know today, were discovered long ago by sailors. These sailors traveled on the gulf stream. The gulf stream is a warm current, flowing along the east
3
Ocean Currents coast of the US. This was discovered in the 1500's by Ponce De Leon. There are a couple types of ocean currents. The destiny current is when the colder, more heavy water sinks beneath the warmer, lighter water. Upwelling is a current that brings cold water, from the deep, up to the top. This water normally brings nutrients up with it.
4
Wind Currents Unequal heating over a small area of the Earth's surface creates local winds. The Coriolis effect is how Earth's rotation causes air to move and water to change direction. Global winds don't travel from north to south because of earth's rotation. The four types of winds include doldrums, trade winds, prevailing winds, and western easterlies. Doldrums are calm, weak surface winds occurring at the equator. Thirty degrees north and south of the equator you can find calm trade winds who bring few clouds and little rain currents. Warm weather rises 5
Wind Currents from the equator and sinks creating horse latitude. The prevailing westerlies lie at 30-60 degrees latitude and are strong and impact on the US weather. The weak, cold winds of the polar westerlies are found by the north and south poles and also influence the US weather. Between 50-60 degrees, cooling take place as the winds approach the poles.
6
Instruments & Images Meteorologists, or weathermen, use different technology to see images of storms, and to predict the weather. Weather balloons carry instruments high into the sky, to measure the temperature, air pressure, and how humid it is. To get pictures, they can send up weather satellites. The first one was sent up in 1906. Cameras on the satellite can take pictures of the Earth' surface, clouds, storms, ice and snow cover.
7
Instruments & Images They also use different computers to make predictions of what the weather will be the next few days. These computers take the past weather and can then guess what it will be. These forecasts are not always accurate, though. An instrument that measures air pressure is called a barometer. There are two kinds of them, a mercury barometer and an aneroid barometer. The picture displays a mercury barometer.
8
Instruments & Images They can also use thermometers. A hydrometer measures the amount of water in the air. A wind vane determines the direction of wind. A rain gauge measures the amount of rainfall and an anemometer measures the wind speed. They also use compasses to find direction.
9
Weather Maps
This weather map displays rain, snow, cold fronts, warm fronts, stationary fronts, high pressure, and low pressure.
10
Isotherms & Isobars On weather maps, sometimes you see curved lines. These lines show places where the temperature or air pressure is the same. Isobars are the lines that connect places with the same air pressure. The numbers along the line show the amount of pressure. Isotherms join places with the same temperatures. The temperature is labeled on the line in either fahrenheit or celsius.
11
Isotherms & Isobars
Isotherm map: you can see the lines connecting the similar temperatures.
Isobar map: you can see the similar air pressures, connected by lines.
12
High & Low Pressure Low pressure areas, marked by a "L" on the map, are caused by swirling centers of low pressure known as cyclones. The air pressure decreases as warm air rises at the center. Winds spiral inward as cooler air from areas with higher air pressure blow towards the low air pressure area. Winds spin counterclockwise and are deflected to the right in the southern hemisphere because of the Coriolis effect. Air rising in a cyclone can cause precipitation and clouds to form. Anticyclones are high pressure areas that are marked by a "H" on a map. The winds spiral outwards 13
High & Low Pressure as they move in the direction of areas of low air pressure areas. As cool air moves down in the troposphere, it warms up and causes the relative humidity to drop. Anticyclones spin clockwise in the southern hemisphere because of the Coriolis effect. The weather is clear and dry from the descending air.
The capital "H" represents a high pressure area.
A low pressure area is represented by a capital "L".
14
Dew Point Dew point is the temperature the air must be, for the water vapor, currently in the air, to condense and form a liquid. When the water vapor condenses, it forms clouds. If the clouds get full, and heavy with water, then it will rain. Dew point is important so weathermen can measure it and can predict if it will rain. Dew point can be measured with thermometers, barometers, other tools, or a complex equation involving humidity, temperature, and air pressure.
15
Types of Clouds There are 3 main types of clouds-cumulus, stratus, and cirrus. Cumulus clouds appear fluffy and round forming at least 2 km off the ground. Clouds that form in flat layers are named Stratus and cover all or most of the sky. Cirrus clouds are wispy and feathery forming at high levels and low temperature. Cirrus clouds are made of ice crystals as a result. When nimbus is added as a suffix, it means that the clouds are rain clouds. Clouds that form high in the sky have the prefix alto, meaning "high". Clouds near the ground level are called fog. 16
Types of Precipitation Precipitation is the water falling back to earth from the clouds. The different types of precipitation are, rain, snow, sleet, and hail. Rain is just water that falls back down to earth. It can be heavy or light, and it can also rain during thunderstorms. Snow is when the raindrops freeze while they are falling. You see it in the winter when it collects on the ground and is fluffy and white. Sleet is the mixture of snow and rain. Hail is when the water freezes all the way and comes down as ice.
17
Fronts Fronts occur when two or more air masses with different temperatures collide.There are four typescold fronts, warm fronts, stationary fronts, and occluded fronts. A cold front occurs when a rapid moving cold air mass collides with a slow warm air mass. The warm air is pushed upwards when the cold air slips under the warm air quickly. Clouds may form and abrupt weather changes can occur. A warm air mass colliding with a slow moving cold mass will cause the cold air to rise and a warm front to occur. The next few days will be foggy and light rain may occur. 18
Fronts The third front is a stationary front where warm and cold air masses meet, but don't collide with one another. It can bring many days of clouds and precipitation. An occluded front is the last front and happens when a warm air mass is caught between two cold air masses and the cold air masses move beneath the warm air. The warm air rises and is occluded, or cut off. The weather may turn cloudy, rainy, or snowy.
19
Hurricanes A hurricane is a really big storm, often occurring near the coast or oceans. Winds can get really strong, and are 119 kilometers per hour, or maybe even higher. Most hurricanes are 600 kilometers across. They are really destructive, but can bring much needed rainfall in dry areas. Hurricanes form over warm, moist areas over the ocean. In the center of the storm is the "eye". It is the calmest part of the storm. In pictures, the eye looks like a hole out of the storm. 20
Hurricanes Hurricanes last longer than most other storms. They can last a week or more. Hurricanes start out over the water, but sometimes move over across land, damaging it. Once it moves over land, it does not have the warm water to fuel it and it fizzles out after about a week, however rainfall can last days after it.
21
Tornadoes Tornadoes are a rapid whirling storm cloud that reaches down to touch the surface of the earth. They form from low cumulonimbus clouds and are more likely to occur during spring or early summer, when thunderstorms are more likely, and late in the afternoon. Moving south from Canada, a cold air mass meets a warm air mass and slips under it causing the warm air to rise.A squall line of thunderstorms is likely to form, containing storms that travel from southwest to northwest. 22
T-Chart Gaby Slides: ~Atmosphere ~Wind Currents ~Weather Maps ~High and low pressure ~Types of clouds ~Fronts ~Tornados
Mckenna Slides: ~Sun's energy/convection ~Ocean Currents ~Instruments/images ~Isotherms/isobars ~Dew point ~Types of precipitation ~Hurricanes
23