Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Coupling between the aerosols and hydrologic cyclesXiaoyan JiangXiaoyan JiangClimatology course, 387HClimatology course, 387HDec 5, 2006Dec 5, 2006OutlinesOutlinesAerosols formationAerosols formationWhy we care about the aerosols and hydrologic Why we care about the aerosols and hydrologic cycle?cycle?The coupling between the ecosystems and the The coupling between the ecosystems and the hydrologic cycle via aerosol processinghydrologic cycle via aerosol processingWhat do we need to know?What do we need to know?What tool we can use?What tool we can use?What data we can use to evaluate the model What data we can use to evaluate the model results?results?Future ChallengesFuture ChallengesAerosols in the atmosphereAerosols in the atmosphereAerosols formationAerosols formationANTHROPOGENIC SOURCESNATURAL SOURCESFossil Fuel Biomass BurningOXIDATIONSecondary and Primary aerosolsWhy we care about the aerosols and Why we care about the aerosols and hydrologic cycle?hydrologic cycle?The interaction between the aerosol and The interaction between the aerosol and meteorological variables.meteorological variables.1.Direct effects---reducing the amount of solar 1.Direct effects---reducing the amount of solar radiation that reaches the surface radiation that reaches the surface 2.Indirect effects ---Changing the properties of 2.Indirect effects ---Changing the properties of cloudscloudsAerosols and their relationships with clouds and rainfall are one of the weakest aspects of current meteorological and climate modelingThe role of aerosols in the hydrologic cycle is The role of aerosols in the hydrologic cycle is unknownunknownThe coupling between the ecosystems and The coupling between the ecosystems and the hydrologic cycle via aerosol processingthe hydrologic cycle via aerosol processingModified from Barth, et al. BAMS, 2005What do we need to know?What do we need to know? Emissions Emissions Anthropogenic and natural aerosolsAnthropogenic and natural aerosols Microphysics and chemistry (dependent on aerosol Microphysics and chemistry (dependent on aerosol type)type)Transformation (removal efficiency of various aerosols)Transformation (removal efficiency of various aerosols)Transport away from source regions (horizontally, Transport away from source regions (horizontally, vertically)vertically) Effect of relative humidity (especially on cloud-scales)Effect of relative humidity (especially on cloud-scales)Precipitation events (intensity and frequency)Precipitation events (intensity and frequency)CloudsCloudsChanges of surface solar radiation induced byurban aerosols for 1 September 2001 based on simulationsfrom a radiative transfer model developed by Chou andSuarez [1999].Here ‘‘diruv’’ and ‘‘difuv’’ represent direct and diffuse UV radiation, ‘‘dirpar’’ and ‘‘difpar’’ represent direct and diffuse photosynthetically active radiation, and ‘‘dirir’’ and ‘‘difir’’ represent direct and diffuse nearinfrared radiation. The ‘‘total’’ represents the total solar radiation, and the values are shown on the right-hand axis in Wm2.The effect of aerosols in the formation of cloudsThe effect of aerosols in the formation of cloudsWhat tool we can use?What tool we can use?A new fully coupled meteorology- chemistry-A new fully coupled meteorology- chemistry-aerosol model is being developedaerosol model is being developed ----WRF-chem----WRF-chemIt is a version of WRF that simulates trace It is a version of WRF that simulates trace gases and particulates with meteorological gases and particulates with meteorological fields. fields. It allows two-way nesting to simulate the air It allows two-way nesting to simulate the air quality and meteorological fields.quality and meteorological fields.Size distribution and composition:sectional size distribution; moving-center or two-moment approach for the dynamic equations for mass and number; each size bin is internally mixedcomposition: SO4 , NO3 , NH4 , CL, CO3 , NA, CA, other inorganics, OC, ECAerosol treatments in WRF-chemAerosol treatments in WRF-chemparticle diameter (m)0.01 0.1 1 10 1000.01 0.1 1 10 100particle diameter (m)massmassmodal approach MOSAIC - sectional approachAccumulation ModeCoarseModeAikenModeMOSAIC has 3 unique components (Zaveri et al. 2005a,b,c):MTEM - Multi-component Taylor Expansion Model: mixing rule for activity coefficients of electrolytes in multi-component aqueous solutionsMESA - Multi-component Equilibrium Solver for Aerosols: thermodynamic equilibrium solver for solid, liquid, or mixed phase aerosols ASTEEM - Adaptive Step Time-split Explicit Euler Method: dynamic integration of the coupled gas-aerosol partitioning differential equations numerically efficient (reduces the # of levels of iterations and # of iterations) without sacrificing accuracy; have been compared with other techniques(Fast,2006)Some results using the fully coupled Some results using the fully coupled meteorology-chemistry-aerosol modelmeteorology-chemistry-aerosol modelWhat data we can use to evaluate the model What data we can use to evaluate the model results?results?Future ChallengesFuture ChallengesCoupled model developmentCoupled model developmentSatellite and ground-based MeasurementsSatellite and ground-based MeasurementsPhysical understanding for the direct and indirect of Physical understanding for the direct and indirect of aerosols in the atmosphereaerosols in the atmosphereThe cloud microphysics The cloud microphysics The role of secondary organic aerosols in The role of secondary organic aerosols in hydrologic cycle due to the importance of water and hydrologic cycle due to the importance of water and energy cycle.energy cycle.Data assimilation of air quality datasets in a Data assimilation of air quality datasets in a coupled modelcoupled modelModel evaluation and uncertainty assessmentModel evaluation and uncertainty assessmentThe feedback mechanismsThe feedback mechanismsThank You !Thank You
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