What causes anticyclones to form? 1. Rossby waves (as they turn away from poles). 2. Dense, cool air in winter over large continental areas. 3. Semi permanent areas of high pressure associated with the global atmospheric circulation e.g. subtropical high pressure zone.
Short term climate change Short term climate change operates over periods of up to a 1000 years. El Ni ño is an example of very short- term widespread climatic disruption.
El Ni ño - a warm ocean current that
occurs in the eastern Pacific off the
coast of Peru in December. It occurs
with a periodicity of 3-7 years and
has a huge impact on the world’s
normal weather systems.
La Ni ña - colder than average sea
surface temperatures in the central
and eastern equatorial Pacific.
La Ni ña usually occurs just before or
just after El Ni ño.
Southern oscillation - the see-saw
like change (switch) in atmospheric
pressure over the eastern and western
equatorial Pacific regions.
ENSO - (El Ni ño-southern oscillation)
the tern used to refer to the full range
of events, i.e. both the changes in the
ocean temperature and atmospheric
Teleconnections - the link between
climate and weather systems over
Thermocline - the sharp and deep
boundary between cold, deep ocean water
and a warmer upper layer.
How does the ENSO work? A normal year.
How does the ENSO work? An El Ni ño year .
How does the ENSO work? A La Ni ña year .
Global Warming: TRUE or FALSE
1. Gases in the Earth’s atmosphere keep the Earth warm by absorbing longwave radiation leaving the Earth’s surface. This naturally occurring effect is called the greenhouse effect. 2. Without the Greenhouse effect the Earth would be about 10 °C colder . 3. The main greenhouse gases are: carbon dioxide, methane, helium and nitrogen oxide. TRUE FALSE FALSE
4. The concentration of greenhouse gases has decreased over the last 100 years. 5. The Earth’s average temperature has increased by about 0.5 °C over the last 100 years due to an enhanced greenhouse effect . 6. The main causes of global warming are an increase in transportation by vehicles, greater use of electricity by homes and industry and clearing forests for farming. FALSE TRUE TRUE
7. The Earth’s climate does not change naturally. 8. Global warming will increase the number of extreme weather events like floods and hurricanes. 9. Global warming will cause sea-level to fall because warmer temperatures mean more evaporation of water from the sea. 10. Global warming will cause ecosystems and habitats to move towards the poles. FALSE TRUE FALSE TRUE