Weather Unit 2

1. Weather Unit 2 Meteorology and the Nature of Storms

2. Weather vs. climate • Weather – short term variations in atmospheric conditions • Climate -is the long term average of variations in weather for a particular area, usually over 30 years of more. What causes weather? • The main cause of all weather is the imbalanced heating of the Earth’s surface. • As the various areas of Earth are heated differently, the air interacts in various ways which we will study in this section.

3. Heating the earth's surface The majority of the Sun’s rays are reflected back to space. However, the increase if Greenhouse Gases from burning of fossil fuels is causing more rays to be blacked back to the earth’s surface, therefore, causing the global average temperature to increase.

4. Connecting air masses to fronts • Front is the front of an air mass, carrying the characteristics of the air mass. • When air masses mix, warm rises and cold sinks creating rainy and sometimes violent weather.

5. Fronts- The boundary at the front of an air mass The front created depends on the characteristics of the air mass.. Cold Front – Cold air moves in, forcing warm air up. Intense precipitation and storms are common with cold fronts. Warm Front – Warm air moves in, displacing the cold air. The warm air rises gradually causing widespread light precipitation. Stationary Front – When 2 air masses meet but neither advances. They are usually similar in temperature. Causes cloudy weather with light winds and occasional precipitation. Occluded Front – When a cold front catches up to and takes over a warm front. Warm air is forced up violently. Typically causes strong winds and heavy precipitation. http://www.physicalgeography.net/fundamentals/7r.html

6. The Jetstream • Yale and Rutgers story on Jetstream • http://climatestate.com/2014/01/05/polar-vortex-jet-stream-and-climate-change/ • NPR.org on the Jetstream • http://www.npr.org/2013/09/25/225754902/wild-weather-tied-to-unusual-jet-stream-activity The Jetstream and Global Climate Change • Jetstream is a fast-moving upper level wind that was created from a combination upper-level air and the Coriolis effect. • It is a narrow band of fast wind that separates cold air from the north and warm air from the south. • It is generally located in the region with the strongest temperature difference, so its location varies season to season as well as slit but is the sole power of our weather.

7. The Jetstream continued:

8. Pressure systems High Pressure System Low Pressure System • Warm air rises and spirals inward. • Then begins to rotate counter clock wise. • Risen air condenses to clouds and precipitation. • Global winds carry the system across US • More dense systems, can “Push” other systems out of its way • Usually brings cooler temperatures with no precipitation • Weather is very pleasant

9. Ice Storm Atlanta, Georgia Weather Forecasting Snow Canyon Toyama, Japan

10. Isotherms and isobars Isobars – Lines on a weather map of equal pressure. Isotherms – Lines on a weather map of equal temperature. What are some other devices that are used to help predict the weather?

11. Station Model A station model is a record of weather data for a particular area at a particular point in time. The station model’s data is put-together to determine the weather patterns not only for that present time but also for the weather of the next several days.

12. Supercells and downbursts A supercell in Montana . Supercellsare intense rotating storms in which updrafts can take 10-20 minutes to reach the top of the clouds. Downbursts are violent downward drafts of wind with speeds over 100 mph. These winds can cause as much damage as tornadoes.

13. TORNADO FORMATION Thunderstorms: Tornadoes: • Tornados: • Wind speeds uneven between high in the atmosphere and ground • Causing horizontal columns of circulating air • Thunderstorm’s updrafts will then turn these columns vertical. Once below the clouds – a tornado has formed Formation of a Thunderstorm: Pop-up Thunderstorms- form in spring in summer during the afternoon from unequal heating of the surface. Frontal Thunderstorms when a cold air mass pushes under a warm air creating uplift and energy. These storms are massive and can create hail and tornadoes. Thunder: the sound of the air rapidly expanding and contracting the cloud, but sound travels slower than light. Lightning: As a cloud charges with static electricity from friction within the updrafts,

14. Tornado Alley

15. Inside view of Hurricane from Planes that drop probe for readings Hurricanes HURRICANE FORMATION Hurricane- A well-defined circulation with winds at least 118km/hr. Interactive hurricane How they form

16. Storm surge A wall of water created as hurricane-force winds force ocean water toward land. Mantoloking, NJ

17. Greenhouse effect and global warming Greenhouse Effect-the natural heating of Earth’s surface by certain atmospheric gases, which helps keep Earth warm enough to sustain life. Global Warming-rise in global temperatures, which might be due to increases in atmospheric CO2 from deforestation and burning of fossil fuels. Inconvenient Truth version of Global Warming If Half of Antarctica melted

18. Global Climate Change So, the Earth's average temperature has increased about 1 degree Fahrenheit during the 20th century. What's the big deal?? At the end of the last ice age, when the Northeast United States was covered by more than 3,000 feet of ice, average temperatures were only 5 to 9 degrees cooler than today.

19. Natural Disasters • 2011 Natural disasters

20. Part II- Biomes

21. Biome Picture and Notes walk • Walk around and examine EACH slide on a different biome. • Observe the pictures closely to understand the type of life that exists there as well as example locations. • After reading each slide, complete the worksheet for the required content on each biome.

22. Grasslands and Savanna • Dry climate 100-20cm • Also, grasslands tend to be in temperate  to subtropical areas, often with cold winters and hot summers.  • Found between deserts and forests • In the northern hemisphere the main grasslands are the prairies of the mid-western United States and Canada; in Eurasia the maker grasslands are the steppes of Russia and the grasslands of the mid-east extending from Turkey to India. Grasslands are also found in South America.  • Threats: There are two major threats to grasslands - conversion to agriculture (or urban areas) and global warming and its attendant changes in precipitation.  Also, mining, animal poaching and development

23. Desert Subtropical deserts precipitation is low, less than 100 cm per year average annual temperature is less than 10° C. subtropical deserts- latitudes of 30° North or South latitude (equator) Temperate deserts- "grassland" from "desert".  Locations from southern California, North/central Africa, Central Asia and central Australia Threats-one of the biggest threats to deserts is development.  Temperate deserts

24. Taiga or Boreal Forest Climate in the taiga is cold, with average annual temperatures from about +5°  to -5°  C 20 cm of precipitation per year to over 200 cm growing season is short, usually less than 3 months. broad bands across North America and Eurasia (Russia/Siberia) Coniferous trees Threats-animal poaching, exploration and development of oil and natural gas reserves, development and logging is always a threat however, most serious threat is Global Warming.

25. Temperate Deciduous Forest Rapid changes from cold and dry to wet and warm or to any of the other corners of the climate envelope are often swift and dramatic.  The average annual  temperature ranges up to about 20° C down to freezing.  Precipitation ranges from around 50 cm yr in the colder regions to over 200 cm/yr.  (lake-effect snows in the winter-until the lake freezes).  Broad-leaf vegetation Threats- Acid Rain, logging, human population and development, global warming also the soils are rich and easily converted to agriculture

26. Rainforest • Warm and wet -250cm of rain per year to about 450 cm/year.  The average annual temperature is above 20° C (never a frost) • tropics, a band around the equator from 23.5° N (the Tropic of Cancer) to 23.5° S (the Tropic of Capricorn) • solar radiation is most intense • The warmth leads to a lot of evaporation, and as warm, moist air rises, it cools, the water condenses, and the water falls back to the earth as rain.  Thus, the warmest areas of the planet also tend to be the wettest, and this sets the stage for the tropical rain forest. Another biome similar to the tropical rain forest is the cloud forest. • Threats-animal poaching, sustenance farming, human population growth, Industrialized agriculture, logging and other minerals and resources being removed for human use.

27. Tundra In the tundra, conditions are cold, with an annual average temperature less than 5° C, and precipitation (mostly in the form of snow) less than 100mm per year (see figure at right).  The summer is brief, with temperatures above freezing lasting for only a few weeks at most.  The ecology of the tundra is controlled by the cold climate and the northern latitude.  The former means that a unique soil structure, permafrost, forms and dominates the biology.  Lichens and mosses,willows, sedges and grasses Threats-airborne pollutants, oil and gas development , global warming