surface water balance (1)

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Surface Water Balance (1). Review of last lecture: Surface energy balance. Incoming shortwave + Incoming longwave = Reflected shortwave + Emitted longwave + Latent heat flux + Sensible heat flux + Subsurface conduction. SWdn =Scos . SWup =SWdn . - PowerPoint PPT Presentation

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  • Surface Water Balance (1)

  • Review of last lecture: Surface energy balancedT/dtSWdn =ScosSWup =SWdn LWdn =Tair4LWup=Ts4LH=CdLV(qsurface- qair) SH=CdCpV(Tsurface- Tair) Fc = - dT/dz Incoming shortwave + Incoming longwave = Reflected shortwave + Emitted longwave + Latent heat flux + Sensible heat flux + Subsurface conduction What is sensible heat flux? What is latent heat flux? Bowen ratio B= SH/LH = Cp(Tsurface - Tair) / L(qsurface - qair) provides a simple way for estimating SH and LH when the net radiative flux Fr is available LH=Fr/(B+1), SH=Fr B/(B+1) Factors affecting soil thermal conductivity Other heat sources: precipitation, biochemical, anthropogenic

  • The global water cycle

  • Components of global water cycleOcean waterLand soil moisture, rivers, snow cover, ice sheet and glaciersSea iceAtmosphere water vapor, clouds, precipitationWater in biosphere (including human beings)

  • Component I: Ocean Covers 70% of the Earths surface

  • Observed Changes in Global Sea Level

  • Observed Changes in Sea Level Largest in the western part of ocean basin

  • Observed Changes in Ocean Heat Content

  • Component II: LandSoil moisture

  • Component II: Land>1000 major rivers flow on the seven continentsAmazon river (#1)Yangtze river (#4)Mississippi river (#6)

  • Component II: LandSnow cover

  • Observed Changes in Snow Cover: Significant melting

  • Component II: LandIce sheet

  • Retreat of Greenland Ice Sheet a huge contributor to sea level rise todayGreenland is responsible for about 10% of the observed global sea level riseand accelerating. Greenland holds 7 m of sea level equivalent.

  • Component II: LandGlaciers

  • Retreat of Mountain Glaciers: a major contributor to sea level riseIPCC (2001)Glacier retreat is a world-wide phenomena.Will affect water supply for millions: Kenya/Tanzania Northern India Andes Mountains

  • Melting in Glacier National Park

  • Component III: Sea ice

  • Observed Changes in Arctic Sea Ice: Significant melting

  • Reduced Arctic sea ice: A result of warming that leads to more warming

  • Component IV: AtmosphereWater vapor flows in the atmosphere

  • Observed Changes in Water Vapor Significant increase

  • Component IV: AtmosphereClouds drifts with the winds

  • Component IV: AtmospherePrecipitation drives many atmospheric circulations which in turn transport water around the worldHadley CirculationMonsoonsWalker Circulation

  • Observed Changes in Precipitation: Significant change in many places

  • A significant fraction of the human body is water (~75%)The remaining: fat, protein, carbonhydrate, other solids

  • So the water in our bodies may come from A stream in the Niagara Fall A white cloud over the tropical Pacific A raindrop in the Amazon rainforest Therefore we need to protect the environment because any pollution we put into the environment may someday come back into our bodiesAn ice sheet in the Arctic Ocean

  • Summary:Components of global water cycleOcean waterLand soil moisture, rivers, snow cover, ice sheet and glaciersSea iceAtmosphere water vapor, clouds, precipitationWater in biosphere (including human beings)

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