Reservoirs of available water Oceans and sea ice - 1370Ice caps and galciers - 29 groundwater - 8 lakes - 0.1soil moisture - 0.1atmosphere - 0.013riivers - 0.001biosphere - 0.001 water reserviors on the continents are negligible in terms of volume small reserviors are importan becuase ofthier role in the water cycle
Exchange processesthey all constantly exchange water except -water trapped in pores of sedimentary rocks -only very slow exchange due to geologicalprocesses processes are evaporation and sublimation evapotranspiration precipitation infiltration percolationsurface runoff and ground water flow
the global water cycle flukes in liquid water equivalents per year Vapour transport (sea to land) = river + ground water flow reservoirs remain constant over = steady state
water and tectonic cycle water is cycled through inner earth over geological time scales it is taken into the lithosphere by subduction of connate water in sedimentary rocks and lossed by volcanic emissions, when these qual each other they are in a steady state and so they are indepndent cycles - they don't really effect each other.
Steady state and residence times Steady state = sum of all sources = sum of all sinks so there fore the reservoir stays constant aswell - allowing reidence times to be calculate, thses are useful for looking at the time-scale of turnover in reservioirs.
Black body radiation the hotter the radiation body the shorter the emiited wavelengths so there fore incoming solar is short waved - uv absorbed by ozone - little abosorption by water and carbon dioxide outgoing radiation is long waved - absorbed by water vapour and carbon dioxide
Incoming solar radiation three fundamantal processes - refelction and scattering - back to space- this is via clouds and gas molecules from the earths surface -absorption via the ozone, clouds and water vapour - absorption via the earths surface the earth approx. absorbs 65% of the incoming solar
Outgoing radiaition required return of absorbed radiaition -radiation emitted from earths surface to space = 5.5%-radiaition emitted back to the atmosphere back to space = 59.5%heat transported from earths surface to atmosphere = 42% -evaporation = 29.5%-conduction and re-emission = 12.5%
35% of incoming solar radiaition gets trapped in the Aatmosphete
Antropogenic Green house effects this is caused by gases being absorb in infrared regions - places left by water - carbondioxide -most abundant and is a natural and anthropogenic sources -Methane is next - Nitrous oxide - CFCs =- tace constituents and currently phased out all models predict significant tempreture rise by atleast 1.2 to 5.8 warmer average 3.5
Ice coes reveal bygone climates windborn dust deposits cause banding with annual layers - help with dating also reveal past greenhouse gas concentrations
Recent records it provides a pre-industrial concentrations of green house gases - glaciers - reaches back as fair as 800000 a BP there has been the strongest increase in recent years
what greenhouse gases are most important? GWP depends on -infrared absorbance -atmospheric lifetime - longer = higher Global warming potentials relative to carbon dioxide Gas Lifetime / a GWP
CO2 5-200 1 = 61% CH4 12 21 = 15% N2O 114 290 = 4%
CFC’s 45-50000 >1500 = 8%Anthropogenic enhancement of the greenhouse effect calculated over 100 years
What is the role of the oceans- Oceanic uptkae moderates atmospheric carbon dioxide concnetrations -Ocean acidification -greenhouse gas emissions from oceans -changes in ocean circulation - weakening of gulf stream = change in waters -sea level rise - melting and themrl expansion, coastline changes, flood risks
measurement of sealevel rise - tide gauges - local -satellite altimneters - global complemented by models which consider -ocean currents and tides -thermal expansion -volume gain current trend ~ 3mm per annume
coastlines sealevels have all ready moved by 100's km due to sea level change caused by -natural climate variabilty - 1 mm - anthropogenic - 15 cm then +40 cm