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Global cycles of water and carbon. Bart van den Hurk (KNMI/IMAU). The atmospheric energy balance. sources: 78 shortwave solar 23 longwave surface 17 thermal 80 latent Total: 199 W/m 2. Trenberth et al, 2009. Turbulent fluxes over land (HTESSEL). Alexander Haumann, 2011.
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Global cycles of water and carbon Bart van den Hurk (KNMI/IMAU) Global distribution of water
The atmospheric energy balance • sources: • 78 shortwave solar • 23 longwave surface • 17 thermal • 80 latent • Total: • 199 W/m2 Trenberth et al, 2009 Global distribution of water
Turbulent fluxes over land (HTESSEL) Alexander Haumann, 2011 Global distribution of water
Water as energy pump energy Transport energy condensation precipitation evaporation ocean land river discharge Global distribution of water
The global hydrological cycle • residence time • in atmosphere: ~10 days • in ocean: ~3000 yrs • land: ~ 1-5 yrs Peixoto & Oort, 1992 Global distribution of water
Transport by the atmosphere eddies and frontal systems driven by temperature- gradients } } Hadley circulation: convection driven by insulation Global distribution of water
North-south (meridional) transport Total transport: North moving eddies (depressions) stationairy eddies (monsoon) large scale circulation South Peixoto & Oort, 1992 Global distribution of water
West African Monsoon www.amma-international.org Global distribution of water
Zonal distribution of precipitation • Strong decline with latitude • Strong signature of ITCZ and Hadley circulation • P over land less than over ocean • ITCZ over land more pronounced Global distribution of water
Zonal distribution of evaporation • Decline with latitude • Relative minimum over equator • clouds • low SST Ocean evaporation Global distribution of water
Zonal distribution of P,E,R Global distribution of water
Comparison of P & E for different continents Global distribution of water
E- and P-estimates Schlosser & Houser, 2006 Global distribution of water
Multiple land models (GSWP2) Peixoto & Oort, 1992 Global distribution of water
Patterns of surface specific humidity • Atypical Atlantic • Low values in deserts • Orography • Large seasonal cycle in transition zone Global distribution of water
Meridional transport • Total meridional transport: • [q][v] = mean meridional circulation • [q*v*] = mean stationary eddies • [q’v’] = transient eddies • Most poleward transport is eddy-driven • Strong transport in mid-latitudes total transport eddy transport Global distribution of water
North-south (meridional) transport Total transport: North moving eddies (depressions) stationairy eddies (monsoon) large scale circulation South Peixoto & Oort, 1992 Global distribution of water
Zonal transport total transport • Reflects circulation of lower half of atmosphere (most moisture) • Easterlies, affected by monsoon • Smaller and less organised • Westward in subtropics, Eastward and midlatitudes, low at equator eddy transport Global distribution of water
Budget equation for land area • with • W = atmospheric water content (mm) • Q = horizontal flux • n = vector normal to area bound, = angle • A = surface of area • R = runoff • ws = terrestrial water storage (soil, groundwater, snow) • used to match atmospheric convergence with river basin discharge Global distribution of water
Example: Rhine basin Global distribution of water
Water vapour convergence from ERA40 Divergence in arid subtropics, convergence in midlatitudes Convergence follows ITCZ Global distribution of water
Global carbon cycle Global distribution of water
CO2 concentration in atmosphere Satellite measurements (AIRS) for 2010 Global distribution of water
Vulnerable carbon pools GCP brochure Global distribution of water
Change of carbon flux between 1980 and 1995 Schimel et al, 2001 Negative flux = storage in land Storage may reverse when respiration exceeds assimilation Global distribution of water
Next week • Given the continental table of P/E/R • Define a subcontinent (e.g. Amazon, Southern-Europe, Sahel, Tibet) and make estimations of these terms Global distribution of water
More information • Bart van den Hurk • hurkvd@knmi.nl Global distribution of water