Global aerosol forecasting and data assimilation

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Global aerosol forecasting and data assimilation

• Overview, Work Plan and Progress Update
• Sarah Lu

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Rationale

• Key mechanisms for utilizing satellite
  observations
• Aerosols affect the interpretation of satellite
  data for atmospheric, land, and ocean
  applications
• Potential for improvements in forecast accuracy
• Radiation Aerosols affects surface radiation
  both directly (via scattering and absorption) and
  indirectly (through cloud-radiation interaction)
• Hurricane Dust-laden Saharan air layer reduces
  occurrence of deep convection and suppresses
  tropical cyclone activities
• Impacts on climate, human health, ecosystem, and
  visibility
• Regional air quality Aerosols (lateral and
  upper) boundary conditions are needed for planned
  PM prediction
• Aviation and visibility Emissions from large
  wild fires affect aviation route planning and
  visibility forecasts

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NCEP global aerosol forecasting and data
assimilation

• OVERVIEW
• Create an integrated operational system for
  forecasting and monitoring the atmospheric
  chemistry and dynamics
• GOAL
• Generate optimal (accurate and affordable)
  description of global distribution of atmospheric
  aerosols
• Provide improved air-chemistry forecasts, through
  improved exploitation of satellite data
• APPROACH
• Incorporate prognostic aerosols in GFS
• Assimilate aerosol measurements (AOD and then
  radiance) in GSI
• Leverage common modeling framework and shared
  software development (JCSDA and ESMF)

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ESMF Component Framework
Atmosphere
ATM Dynamics
ATM Physics
Mark Iredell
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Chemistry/ Transformation
Sinks
Sources
Depends on surface winds
Topographic Source 4 size classes 0.1 6 µm
radius
Dust
Sedimentation Dry deposition Wet removal
Improved representation of sub-micron
particles 5 size classes 0.03 10 µm dry radius
Swelling by RH
Sea salt
Based on measured sea surface concentration
Chemistry
DMS
Oxidation to SO2
Anthropogenic Biomass burning Oxidation of DMS w/
OH and NO3
Chemistry Dry deposition Wet removal
SO2
Oxidation to SO4
Anthropogenic Biomass burning Oxidation of SO2 w/
OH and Aqueous reaction with H2O2
Dry deposition Wet removal
SO4
Fractionation of Hydrophobic Hydrophilic
Components
Dry deposition Wet removal (hydrophilic only)
Biomass burning Biofuel Anthropogenic,
other Biogenic OC
BC/OC
Arlindo da Silva (GMAO)
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ESMF Component Framework
Atmosphere
GOCART GridComp
SS
SU
DU
OC/BC
ATM Dynamics
ATM Physics
Mark Iredell
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Prototype aerosol forecasting system
GFS forecast from T0
Communication of dynamics info
GOCART forecast from T0
Communication of chemical info
GFS forecast from T
GOCART forecast from T
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NOAA medium range weather forecasts

• BASELINE CONDITION
• Climatology-derived aerosol distributions are
  used in the GFS
• Background aerosol conditions are assumed in the
  GDAS radiative transfer scheme
• SHORTCOMING
• The effects of aerosols on radiation, clouds, and
  convection are poorly constrained in the GFS
• The effects of aerosol attenuation on radiance
  assimilation are yet to be quantified in the GDAS
• PROPOSED ENHANCEMENT
• Global aerosol products will improve the
  representation of aerosol distribution and
  variations within the GFS/GDAS system

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Aerosol distributions vary significantly from
day to day
Sulfate AOT
Dust AOT
Apr 02, 01
Apr 12, 01
Mian Chin (GSFC)
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Aerosol vertical distribution changes
April
September
Aerosol extinction at 550 nm
Mian Chin (GSFC)
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Aerosol composition changes with
locations/seasons
April
September
Mian Chin (GSFC)
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NOAA air quality forecasts

• BASELINE CONDITION
• Default static boundary conditions are used for
  PM air quality predictions
• SHORTCOMING
• The use of static boundary conditions cannot
  account for the impact of long-range aerosol
  transport on PM loading over the US
• PROPOSED ENHANCEMENT
• Global aerosol products will provide improved PM
  lateral boundary conditions for the AQF system
  and, consequently, improve PM air quality
  forecasts

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Dust Evolution and Trans-Pacific Transport
Mian Chin (GSFC)
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How do the foreign sources affect native air
quality?
Altitude (km)
SO4 µg m-3

• Sulfate over North America
• Most sulfate stays in the boundary layer
• Pollution from Asia can travel around the
  hemisphere at higher altitudes above BL
• European pollution makes its way over N. America
  at higher latitudes
• In the BL over North America, most sulfate is
  from is own regional source

Altitude (km)
from Asia
Altitude (km)
from Europ
Altitude (km)
from N America
Mian Chin (GSFC)
East Coast
West Coast
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How do the foreign sources affect native air
quality?
Altitude (km)
Dust µg m-3

• Dust Over North America
• Dust plume has broad vertical extension above the
  BL
• Most dust below 6 7 km is from Asia
• Dust from the Middle East contributes to about
  10 dust loading
• African dust is an important contributor to the
  dust level in the tropics and at high altitudes
  above 6 7 km

Altitude (km)
from Asia
Altitude (km)
from Middle East
Altitude (km)
from Africa
Mian Chin (GSFC)
East Coast
West Coast
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An end-to-end work plan
In Progress

• Adoption of GOCART modeling component
• Modification of GFS radiation module
• Extension of GFS tracer capability to include
  aerosols
• Development of ESMF interface for coupling GOCART
  and GFS
• Deliverable GFS-GOCART simulated aerosol
  products
• Utilization of MODIS/OMI measurements
• Incorporation of MODIS/OMI into NCEP operational
  data tank
• Evaluation and error analysis based on AODs and
  radiance
• Deliverable MODIS/OMI calibrated aerosol
  products
• Integration of global aerosol products in NOAA
  decision support
• Interface global aerosol products with CMAQ-NAM
• Couple global aerosol products with GFS/GSI
• Adopt global aerosol products in SST analysis
  system
• Deliverable Benchmarking of improvements in NOAA
  decision support
• Research-to-operation transition
• Optimize the configuration to fit operational
  resource and time constraints
• Manage the logistics for operational
  implementation
• Deliverable Operation implementation

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Aerosol products from EC GEMS (Global and
regional Earth-system Monitoring using Satellite
and in situ data)
Products Usage
4D distribution of aerosol concentrations (troposphere and stratosphere) climate research monitoring of the atmospheric chemical composition monitoring of the stratosphere (air traffic) monitoring of volcanic eruptions for local populations initial and boundary conditions for regional air quality models
4D distribution of aerosol optical properties (troposphere and stratosphere) atmospheric corrections for remote sensing of land surfaces and ocean prediction of surface UV radiation
Surface distribution of particulate matter PM regional air quality
Improved visibility range air traffic, tourism
Improved photosynthetically active radiation (PAR) at the surface study of the carbon cycle monitoring of the Kyoto protocol
Aerosol deposition flux (dry and wet) study of the ocean biology impact on ecosystems (acid rain monitoring)
Improved photolysis rates regional air quality global monitoring of the atmospheric chemical composition
Improved surface, atmospheric, and top-of-atmosphere radiative budget climate research
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Thank You