Coupling between the aerosols and hydrologic cycles Xiaoyan Jiang Climatology course, 387H Dec 5,...
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Transcript of Coupling between the aerosols and hydrologic cycles Xiaoyan Jiang Climatology course, 387H Dec 5,...
Coupling between the aerosols and hydrologic cycles
Xiaoyan JiangXiaoyan JiangClimatology course, 387HClimatology course, 387H
Dec 5, 2006Dec 5, 2006
OutlinesOutlines
Aerosols formationAerosols formation
Why we care about the aerosols and Why we care about the aerosols and hydrologic cycle?hydrologic cycle?
The coupling between the ecosystems and the The coupling between the ecosystems and the hydrologic cycle via aerosol processinghydrologic cycle via aerosol processing
What 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 Challenges
Aerosols in the atmosphereAerosols in the atmosphere
Aerosols formationAerosols formation
ANTHROPOGENIC SOURCESNATURAL SOURCES
Fossil Fuel Biomass Burning
OXIDATION
Secondary and Primary aerosols
Why 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 unknownunknown
The coupling between the ecosystems and The coupling between the ecosystems and the hydrologic cycle via aerosol processingthe hydrologic cycle via aerosol processing
Modified from Barth, et al. BAMS, 2005
What 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)CloudsClouds
Changes of surface solar radiation induced byurban aerosols for 1 September 2001 based on simulations
from 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 clouds
What 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-chem
It 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 mixed
composition: SO4 , NO3 , NH4 , CL, CO3 , NA, CA, other inorganics, OC, EC
Aerosol treatments in WRF-chemAerosol treatments in WRF-chem
particle diameter (m)0.01 0.1 1 10 100 0.01 0.1 1 10 100
particle diameter (m)
mas
s
mas
s
modal approach MOSAIC - sectional approach
Accumulation Mode
CoarseModeAiken
Mode
MOSAIC 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 solutions
MESA - 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 model
What data we can use to evaluate the model What data we can use to evaluate the model results?results?
Future ChallengesFuture Challenges
Coupled 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 mechanisms
Thank You !Thank You !