North Atlantic Climate Flashcards
what are then fundamental drivers of weather?
circulation, gradients in temperature and pressure, fluids will naturally want to move an area of low pressure and temp
how does circulation work in the atmosphere?
three cell model, rising air at the equator, sinking air around 30 degrees N causing adiabatic warming and high surface pressure
what is the polar jet?
region of fast air high up, that meanders hugely, causes the formation and collapse of Rossby waves, low pressure stormy systems are more likely under the polar jet
what is the polar vortex?
large area of low pressure, cold air, the jet stream weakens and becomes wavier allowing cold air to dip southward and warm air to move in (cold air spillage)
what happens at the surface?
pressure gradient force and Coriolis force combine to dictate the path of the air flow
what is the Coriolis effect?
the spinning in each hemisphere causes the winds to deflect right in the northern hemisphere and left in southern
what is the weather?
meteorological conditions at a given point in time
what is the climate?
prevailing meteorological conditions over an extended baseline period (30 years often)
processes dictating weather in north atlantic climate?
positions of the jet stream determine which parts of Europe are the most stormy also position of polar front
what else dictates North atlantic climate?
oceans carry substantial heat, strong association between position of gulf stream and position of cold waters.
ocean circulation and climate?
surface water conditions affect atmosphere above, through sensible heat transfer, evaporation and condensation, warm NAC produces warm, wet atmospheric conditions
what happens to the NAC going north?
loses heat to the atmosphere, surface water evaporates, increasing salinity, causing water sinking, causing deep water formation
what is North Atlantic Climate variability?
North atlantic oscilation , occurs every 30-50 years, defined as difference in pressure between reykjavic and lisbon
what is the North atlantic oscialtion?
it controls the strength and trajectory of westerly winds,
positive NAO phase has a large pressure difference and a negative NAO has small pressure differences
positive NAO?
warm wet conditions over NW Europe and cold dry over southern europe
