B_chapter+27

27.2 Global Winds and Ocean Currents

Scientists collect patterns of the heat and cool on Earth, they get this information from satellite images. The National Oceanic and Atmospheric Administration use infrared photos to map and measure how much heat is reflected and emitted from different areas of Earth. The scientist who analyze the data need a way to pinpoint places on the infrared pictures of Earth, a way they can do this is use a common system of man-made grid called longitude and latitude.

** Latitude lines ** are parallel lines that measure distance from the and are also parallel to the equator. They are labeled in degrees running from east to west. .

** Longitude lines ** run from north to south, they are vertical lines. The 0 degree longitude is called the prime meridian.

Together longitude and latitude lines help scientist pinpoint exact locations all over the Earth. With this, they can use satellite photos to help with climate research.



** Temperature and Latitude ** With latitude comes different temperatures, the temperatures on Earth varies with the latitude. Like in the northern hemisphere it is colder compared to the southern hemisphere. For an example, birds flying south in the winter time because the south is warmer. Vice versa with the southern hemisphere when it's winter time there. Pretty much the further you are away from the equator the colder the temperature gets. At higher latitudes, the less intense the solar radiation is. Usually the hottest places on Earth are near the equator because the sun is closets and hits directly overhead, year round. But around and near the north and south poles, the temperatures are much colder. The reasoning behind this is because when the suns energy hits the north and south poles it hits it at an angle. The heat has "spread" out and is now less intense. While at the equator it is much more warmer because the sun's energy is hitting it directly being more intense.

**Fact:** The average yearly temperature at the equator is 80 degrees Fahrenheit while at the north pole it is 0 degrees Fahrenheit.

**Temperature and Earth's Rotation** As the Earth rotates, the part of the globe facing the sun absorbs more radiation than it discharges and warms. The Earth produces some of the gained energy as infrared radiation. The newly emission of heat cools the dark side of the planet. For example clear nights are usually cooler than cloudy nights because on clear nights, the emitted radiation escapes into space. The clouds absorb the radiation produced by Earth's surface, making the temperature near the ground warmer. Another example of temperature being affected by the Earth's rotation is the arctic regions experiencing more daylight but not absorbing the heat with all that extra daytime. Why doesn't get warmer? Well, for two reasons. One, the sunlight is not very intense to begin with, and second, the snow reflects a lot of the incoming radiation. Only a small portion of the incoming radiation is absorbed. **Why Does Earth Have Seasons?**  Why do we even experience winter and summer? How does is work? Is it because in the summer time we are close to the sun and in the winter time we are farther away from the sun? WELL! To answer your questions, those are usually a common misunderstanding. The real reason has nothing to do with how close we are to the sun, the reason why we have seasons is because Earth's orbit is circular and because Earth's axis is tilted at an angle. An example is in January, the northern hemisphere is pointed away from the sun while the southern hemisphere is pointed towards the sun. The rays of sunlight that have finally reached the northern hemisphere are spread out and less intense than the ones that reached the southern hemisphere first. http://youtu.be/rcquRMaVSKU

One form of a Global wind is a __thermal__- A convection current in the atmosphere. a thermal forms when surfaces like the ground or streets takes in solar radiation and sends out the energy as heat, the heat then starts to warm the surface over the ground. the warmer air molecules start to gain kinetic energy and start to spread out. the heated air rises higher causing cold air to move to the ground. The colder air is then warmed and sent back up. This process helps out long winged birds like hawks fly because they ride the warm air that is pushed up.

__The convection currents__ surround the earth in the atmosphere. These types of global winds form when warmer air from the equater moves to the poles. Also when the colder denser air from the poles start to move toward the equator. the flowing air is called wind.

Because of the earth's rotation, the warm air from the equator can't make it all the way to the poles. so these convection currents are formed in to Global wind cells, forming in different parts of the hemisphere.

This happens because when the cold air moves from the north pole to the equator in a straight line, the earth's rotation makes it seem that the wind is bending in another direction. the flowing air goes through the same process when it travels from the equator to the poles, this process is called the __Coriolis effect__.

Winds are defined by where they flow from, like winds from the west are called west winds, and winds from the southwest are called southwest winds. When a wind only travels between the equator and 30 degrees latitude it is called __trade winds__. they form when the warm air from the equator moves to the poles and start to cool off during the process and then goes back to the equator.

Another wind pattern is the __polar easterlies__, thet form when the air from the poles that move to the equator start to move down and then start to cool off and spread across the surface of the earth. Any winds that are stuck between these two wind patterns are called __prevailing westerlies__. The border between the prevailing westerlies and the polar easterlies are called the __Polar front__. Because of the Coriolis effect all those wind patterns travel around the earth.

When the wind moves over the oceans it pushes them and causes __Surface ocean currents__. When they move the ocean it circles the earth gyres. Ocean currents can also happen at the bottom of the oceans. this process is responsible for cooling off most of the earth.

** 27.3 Weather Patterns ** Two important factors that shape climate in a region is temperature and pressure. The higher temperatures cause air to expand and rise near the equator and produce wind and ocean currents. The pressure difference between cold and warm air cause air to flow from regions of high to low pressure. The bigger the difference in pressure, increases the speed of air flow or wind. Another important factor is water. Without water in our atmosphere we wouldn't have rain, hail, snow, or sleet. There is always water in our atmosphere even when the sky's are blue. ** Temperature, air pressure and water in the atmosphere are the three most important factors that shape and influence weather patterns. ** ** Phase Change in the Atmosphere ** The state of water, whether it's solid, liquid, or gas, depends on the temperature and atmospheric pressure. As the temperature increases, the motion of water rises. As temperature rises so does the rate of evaporation. Pressure also affects the change of state, as the atmospheric pressure decreases it allows more water molecules to escape from the liquid to gas state. So, as the pressure decreases the evaporation rate increases. The three phases that the water goes through in the atmosphere is the ice crystals. Small water droplets, too small to see. All the other remaining water in the atmospherics are truly in the gas state. The water exists in all three states while in the atmosphere. Since the combination of temperature and pressure in the atmosphere are always changing, water is also changing constantly. **Precipitation** If water is cold enough it reaches a dew point, but keeps its same pressure. However, if the air temperature closer to the ground is warmer than the air higher up, the crystals will melt and the precipitation will fall as rain. Condensation is a warming process that uses latent heat to break up water molecules to create rain. When the ground cools late at night or early in the morning the temperature of the ground is below the dew point. The air near the ground gets colder and some water vapor becomes in the form of dew.

**Air masses and front** An air mass is a large body of air with consistent temperature and moisture characteristics throughout. Air masses can cover areas as large as 750,000 square miles. These air masses form when air remains stationary over an area long enough to take on the characteristics of the surface below

27.4 Storms:

Storms are a very interesting and an important part of climate change. A storm is a disturbed state of an astronomical body's atmosphere which especially affects its surface and strongly applies severe weather. A storm can be marked by rain, snow, hail, severe wind, lighning/thunder, etc... storms can be mild or life threatening.

Here are different types of storms:

Thunder storms: Thunderstorms arise when air near the ground is strongly warmed and rises high into the troposphere. As the air rises it cools and condenses, forming a towering and cumulonimbus cloud. Some of the colder air from high regions is dragged along with the falling rain, causing a downdraft of cooler and denser air. eventually some of the droplets in the cloud becom dense enough to fall out of the sky as rain. Also with lighning comes thunder, the process that causes lightning with vaopr particles inside of the storm cell colliding, and electrical charges get transfered from one particle to another. The chargers that are positive tend to build up on smaller particles, and the charges that are negative tend to build up on the positive Gravity and wind are what can make the particles separate The positive particles acumulate at the top of the cloud where as the negative particles fall to the bottom. That is why some people who have experienced a lighning strike, sa that they first felt their hair stand up, the positive charge causes it to. The negative charges in the cloud are attracted to tye positively charged ground. When enough of the charges have been separated by the storm, the cloud, air, and the ground act like a giant circuit. All of the charges that are acumulated flow from the cloud to the ground, making the air glow like a bright streak of light by heating it. When the heated air expands, we hear thunder.

Hurricanes:

These storms are a type of Tropical cyclone which is a storm with a low pressure center surrounded by a rotating arrangement of thunderstorms those storms can cause heavy rain and strong winds hurricanes strengthen as water evaporated from the ocean gets as the saturated air rises, resulting in condensation of water vapor contained in the moist air. Unlike other cyclones, the center of the hurricane, comonly known as the "eye" of the hurricane, regardless of the height will be warmer than its surroundings, a phenomenon called "warm core". How Hurricanes Form:

Typically, ocean water that is at least 81 Degrees fahrenheit. The warm moist air is a good energy source for the energy for the hurricane. As the warm air starts to rise, the water vapor inside of it condenses. That is when cloudss, and thundershowers form. The condensation releases latent heat, causing the surrounding air to get even warmer. As all of that air rises and begins to expand, it makes an area of low pressure at the surface of the water. The pressure difference causes surrounding air to rush toward the center. The path of the air that is rushing curves due to the coriolis effect, and a rotating system forms, thus, a Hurricane!

Needed conditions for the development of a hurricane:

The wind must be at a speed of at least 75 miles per hour, the warm water must be at least 46 meters deep. Otherwise when the storm mixes up the water, cooler water that is brought to the surface will slow the rise of warm, moist air, and the stiorms strength with weaken. Also the air must be warm and moist. 5,500 meters above sea levl is usually where we would like the warm moist air to be. As the air is pulled into the storm, it provides the water vapor that must condense and release latent heat, in order for the storm to get even stronger.Also the winds must be in good condition, if the wind is blowing all over the place, and not in one direction, it can push the rising warm air in different directions, breaking up the storm.

fact: 96 Tropicals storms happen worldwide each year. Most commonly in the wester north pacific, and the indian ocean.

Tornadoes:

Tornadoes, similar to hurricanes, are a rotating cyclone however the are smaller, and the wind speeds of the tornado are much faster than those of a Hurricane. The speed can reach 400 Kilometers per hour. Like Hurricanes, the tornado begins with thunderstorms. Cold air, and hot air begin to chase each other around forming a funnel cloud. Then the funnel cloud touches down, and like a vacuum, sucks everything up, and with the rushing winds, destroys and tears everything down in its path. Tornadoes mostly happen in the winter, most commonly in areas with really flat land. Texas, or Oklahoma is a good example of places that often get devastating Tornadoes. Most Tornadoes last 10 to 20 minutes however, powerful tornadoes can last an hour or more.

El Nino:

El Nino is when warm water from the west flows back tward their shores. It cuts off a pattern in which cold water from the ocean depths flows up to the surface around the coast of peru.

The main source I used for this wiki, is the text book, the book had alot of information about storms.

This relates to other things we have learned in science class because we learned about latent heat, just recently. Latent heat is actually one of the reasons a hurricane happens because the air needs that latent heat from the condense water in order for the hurricane to form.



27. 5 Weather and Climate We have been learning about seasonal changes wind and oceans currents and weather patterns. All of these elements work together to produce different climate in different parts of the world

Fog desert is a type of the desert this type of deserts is on the west of coast of the continents between 20 and 30 latitude. It depends on where the deserts located. All deserts are dry and there is very little rain The rain forest has a lot of rain of at least 200 centimeters per year. All of the rain forest is close to equator between 23-5 n latitude and 25. 5 s latitude. Although the rain forest covers less than 6 percent of earths land half of all plants and animal plants are found there. There are two types of grasslands there called savannas and temperate grasslands. Grasslands are found in every continent except for Antartica Savannas are characterized by seasons rainy and dry. The rainy season last for six to eight months each year. 50 to 127 centimeters of rainfall. The is followed by drought witch in many areas culminates a wildfire. Temperate grasslands Temperate grass lands grow in the middle latitude regions this lands are called plains this lads resave most of there precipitating during the spring and early summer. Most of these grasslands are found in the interior of continents far from large bodies of water the average rainfall is between 51 and 89 centimeters. Summer tempters can reach over 30 c in the summer while in the winter it goes below -40c. Temperate forest are found in the middle of latitude regions .The winter temper in some places temperatures goes as low as – 30c and in the summer it could be as warm as 30c.