Week 9 Flashcards
List three oscillations and where they affect.
ENSO = El nino and the southern oscillation over - tropical pacific PDO = Pacific decadal oscillation NAO = North Atlantic Oscillation
What is conisdered normal conditions?
Wet indonesia, dry south america
- upwelling occuring in south america
- high pressure near south america
What is cosidered ENSO conditions (name 4)
high pressure over western pacific (indonesia)
- Low over south america.
- Warm water near south america,
- Weak upwelling
What is La Nina? what are the conditions like?
- Lower than normal pressure over western pacific
- high than normal over south america
Difference between El nino and La nina?
El nino, above average surface temperature
La nina, Below average surface temperature
How predictable is El nino?
Not very predictable in terms of magnitude, but we observe that there is heating every 5 years or so.
Why does El Nino occur?
Still very uncertain, limited data has been taken, unsure of proper techniques to use.
What are beieved to be the main causes of El nino?
It is believed to be ocean atmosphere interactions such as
- SST sea surface temperature
- SSP, sea surface pressure
What processes indicate a PDO (pacific decadal oscillation) (+ vs -)
PDO + = High SST in tropics and western north america
Low SST in the western north pacfic
- PDO - is the opposite.
What processes indicate a NAO or North Atlantic oscillation? When is this likely to occur?
Icelandic low pressure
- Azore high pressure
- NAO + - warmer south east coast US, warmer nordic countries, and colder west coast of africa, developed during winter.
What is Detection and attribution?
Detection is the reconition of a signal amongnst noise,
Attribution is determining the cause of the detected trend
What has been detected and attrbuted in the last years
We have detected the impact that humans have had on changing climate, this is refered to as anthropogenic forcings,
What is the is the GHG that contributes the most to globa warming, what are main sources of it?
CO2, the two main sources are
- Forest clearing
- fossil fuel burning.
Where is the CO2 content the highest? where does the rest of it go?
CO2 content is the highest in the NH, specially in the atmosphere.
The rest is absorbed by the biosphere, and the shallow ocean.
Who are the main producers of CO2
North america
Europe
East Asia
(the most developed and economically active countries.
Where do observe CO2 as a sink or a source in our oceans?
CO2 can be absorbed in colder waters because CO2 has a greater solubility in cold water,
In contrast, warm waters around the tropics act as sources of CO2 in the oceans.
What actions have been taken in some tropical countries to combat CO2 concentrations
countries such as malaysia, brazil, australia have all undergone reforestation plans which have reduced Atmospheric CO2
What is the source of CH4 emissions. How much of the GHG effect does it contribute?
- Rice irrigations
- Tending livestock
- destruction of Wetlands
~16%
What does global warming potential mean?
What factors does this depend on?
Indicator developed to measure the relative power of a given amount of different GHG’s relative to CO2. - Effectiveness as GHG
- Lifetime in atmosphere
What is CO2 equivalent
Mass of CO2 GHG that is required to have the same effect as 1 kg of Other GHG’s
What contributes to the Global warming potential of the day. Describe specific conditions
Life time has a large impact, gases that lie in a place for longer have a greater GWP.
Effectiveness relates to heat capacity, greater heat capacity will have greater effect.
How do you convert CH4 emissions to CO2?
1 kg of CH4 = 25 kg of CO2 in GWP.
17*25 = 425
Why do we observe a leveling off point of global temperature in icehouse and green house conditions?
Green house conditions,
- CO2 saturation
- Absence of ice
Ice house
- limit to which albedo feedback is strongest
