met-o midsterms

• Climate is the weather conditions prevailing in an area in general or over a long period.
• Climate is the weather conditions prevailing in an area in general or over a long period.

  • is the long-term weather pattern in a region, typically averaged over 30 years.
• Climates can be classified according to the average and typical variables, most commonly

  temperature and precipitation.
• Paleoclimatology is the study of ancient climates.
• Different Climate Types?

  There are approximately five main climate types on Earth:

   Tropical

   Dry

   Temperate

   Continental

   Polar
• A: Tropical. In this hot and humid zone, the average temperatures are greater than 64°F (18°C)

  year-round and there is more than 59 inches of precipitation each year.
• B: Dry. These climate zones are so dry because moisture is rapidly evaporated from the air and

  there is very little precipitation.
• C: Temperate. In this zone, there are typically warm and humid summers with thunderstorms and

  mild winters.
• D. Continental. These regions have warm to cool summers and very cold winters. In the winter,

  this zone can experience snowstorms, strong winds, and very cold temperatures—sometimes

  falling below -22°F (-30°C)!\
• E: Polar. In the polar climate zones, it’s extremely cold. Even in summer, the temperatures here

  never go higher than 50°F (10°C)!
• Ocean current


  Continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences
• Ocean currents of the world

  • The main ocean current that affects the UK is the Gulf Stream
• Gulf Stream


  Warm ocean current in the North Atlantic flowing from the Gulf of Mexico, northeast along the U.S coast, and from there to the British Isles
• El Niño


  The irregular warming of surface water in the Pacific
• La Niña

  The cold counterpart to El Niño
• La Niña is Spanish for 'the girl child', and it also brings with it weather extremes
• The two most important factors in the climate of an area are temperature and precipitation.
• Climate Change

  Climate change is a long-term shift in global or regional climate patterns. Often climate change

  refers specifically to the rise in global temperatures from the mid-20th century to present.
• Anthropogenic climate change

  Climate change caused by human beings
• In the United States, transportation constitutes the single-largest source of greenhouse gas emissions. agriculture contributes 11 percent to US Gas Emissions.
• Precipitation (rain and snowfall) has increased across the globe, on average. Yet some regions are experiencing more severe drought, increasing the risk of wildfires, lost crops, and drinking water shortages.
• Sea levels are expected to rise between 10 and 32 inches (26 and 82 centimeters) or higher by the end of the century
• El Niño is the “warm phase” of a larger phenomenon called the El

  Niño-Southern Oscillation (ENSO).
• (ENSO). La Niña, the “cool phase” of ENSO, is a pattern that describes

  the unusual cooling of the region’s surface waters. El Niño and La Niña are considered the ocean

  part of ENSO, while the Southern Oscillation is its atmospheric changes.
• the planet has been in a cold phase (La Niña) of the El Niño-Southern Oscillation

  (ENSO) climate pattern.
• Pressure varies from day to day at the Earth’s surface - the bottom of the atmosphere. This is,

  in part, because the Earth is not equally heated by the Sun. Areas where the air is warmed

  often have lower pressure because the warm air rises. These areas are called low pressure

  systems. Places where the air pressure is high, are called high pressure systems.
• A low pressure system has lower pressure at its center than the areas around it.
• A high pressure system has higher pressure at its center than the areas around it. Winds blow

  away from high pressure. Swirling in the opposite direction from a low pressure system, the

  winds of a high pressure system rotate clockwise north of the equator and counterclockwise

  south of the equator. This is called anticyclonic flow. Air from higher in the atmosphere sinks

  down to fill the space left as air is blown outward. On a weather map, you may notice a blue H,

  denoting the location of a high pressure system.
• Pressure gradient


  Difference in pressure between two points
• Vertical pressure gradient


  • Exists naturally due to the weight of air molecules pulled down by gravity
• Horizontal pressure gradient


  • Mostly exists because of uneven heating of Earth's surface
• Horizontal pressure gradient formation

  1. Air rises in some places

  2. Air falls in others

  3. Forming convective loops

  4. Air molecules pile up in some locations (high pressure)

  5. Air molecules spread out in others (low pressure)
• Pressure gradients have many causes. But within Earth's atmosphere, most pressure gradients

  are caused by uneven heating of Earth's surface.
• Geostrophic wind is the wind that is caused by two important effects in the earth's

  atmosphere. Pressure gradient force and Coriolis Effect.
• The direction of geostrophic winds is determined by the

  balance created by the pressure gradient force.
• The global circulation

  Over the major parts of the Earth's surface there are large-scale wind circulations present. The

  global circulation can be described as the world-wide system of winds by which the necessary

  transport of heat from tropical to polar latitudes is accomplished.
• In each hemisphere there are three cells (Hadley cell, Ferrel cell and Polar cell) in which air

  circulates through the entire depth of the troposphere.
• Hadley cell

  The largest cells extend from the equator to between 30 and 40 degrees north and south, and are

  named Hadley cells, after English meteorologist George Hadley.
• Ferrel cell

  In the middle cells, which are known as the Ferrel cells, air converges at low altitudes to ascend

  along the boundaries between cool polar air and the warm subtropical air that generally occurs

  between 60 and 70 degrees north and south. This often occurs around the latitude of the UK

  which gives us our unsettled weather. The circulation within the Ferrel cell is complicated by a

  return flow of air at high altitudes towards the tropics, where it joins sinking air from the Hadley

  cell.
• Polar cell

  The smallest and weakest cells are the Polar cells, which extend from between 60 and 70 degrees

  north and south, to the poles. Air in these cells sinks over the highest latitudes and flows out

  towards the lower latitudes at the surface.1