2006-10-16 u wisconsin seminar
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Thoughts on Atmospheric Aerosols:Science, Air Quality and Informatics
Rudolf B. Husar
CAPITA, Washington UniversitySeminar Presented at U. Wisconsin,
Madison, WI, October 16, 2006
Major Biogeochemical Processes/Flows Visualized by Aerosols:
Volcanoes
Dust storms Fires
Anthropogenic pollution
Aerosols as Indicators of Global Processes and Change
Radiative Climate Human Health Visibility Acid Rain……
As aerosols pass through the atmosphere, the effects include:
Complex Physico-Chemical Properties:
Particle Size
Particle Composition, Shape
Scientific Challenge: Characterization of Aerosols
• Gaseous concentration: g (X, Y, Z, T)
• Aerosol concentration: a (X, Y, Z, T, D, C, F, M)
• The ‘aerosol dimensions’ size D, composition C, shape F, and mixing M determine the impact on health, and welfare.
Dimension Abbr. Data SourcesSpatial dimensions X, Y Satellites, dense networks
Height Z Lidar, soundings
Time T Continuous monitoring
Particle size D Size-segregated sampling
Particle Composition C Speciated analysis
Particle Shape/Form F Microscopy
Ext/Internal Mixture M Microscopy
Aerosol complexity is due multi-dimensionality
Characterization requires 6-8 independent dimensions
Technical Challenge: Characterization
• PM characterization requires many different instruments and analysis tools.
• Each sensor/network covers only a fraction of the 8-D PM data space.
• Most of the 8D PM pattern is extrapolated from sparse measured data
Satellite-IntegralSatellites, integrate over height, size, composition, shape…dimensions
These data need de-convolution of the integral measures
Global Earth Observing System of Systems (GEOSS) Challenges:
Integration of 6 (8) – Dimensional Multi-sensory Data and Models
Challenge: Vertical Distribution of Aerosols
Regulatory Challenges:Natural Aerosols
Natural haze - windblown dust, biomass smoke and other natural processes
Man-made haze - industrial activities AND man-perturbed smoke and dust emissions
Man-made Emissions Eliminated
Natural Conditions by 2064
Just like the human eye, satellite sensors detect the total amount of solar radiation that is reflected from the earth’s surface (Ro) and backscattered by the atmosphere from aerosol, pure air, and clouds. A simplified expression for the relative radiatioin detected by a satellite sensor (I/Io) is:
I / Io = Ro e- + (1- e-) P
Satellite Detection of Aerosols
Today, geo-synchronous and polar orbiting satellites can detect different aspects of aerosols over the globe daily.
where is the aerosol optical thickness and P the angular light scattering probability.
Height Type Size Angle Shape
dHdCdDdPdSSPDCHI
Satellite Remote Sensing Since 1972
• First satellite aerosol paper, Francis Parmenter, 1972• Qualitative surface-satellite aerosol relationship shown, 1976• Focus on regional ‘hazy blobs’, sulfate pollution
Regional HazeLyons W.A., Husar R.B. Mon. Weather Rev. 1976
SMS GOES June 30 1975
AVHRR satellite optical depth climatology over the oceans, 1988-90
Husar, Prospero, Stove, 1997
Surprise: Small Sulfate Plume, Spring, Summer Only
MISR Seasonal AOT (MISR Team)
Major smoke emission regions by season
SeaWiFS AOT – Summer 60 Percentile1 km Resolution
Satellite Data Increases Spatial Resolution
PM25 Surface Conc. JJA
SeaWiFS AOT. JJA
SeaWiFS AOT. JJA, Terrain
AOT in Valleys
Satellite Summary
• Satellite data have aided the science of Particulate Matter since the 1970s
• Satellite data have supported PM air quality management since the 1990s.
• Past satellite data helped the qualitative description of PM spatial pattern
• Quantitative satellite data use and fusion with surface data is still in infancy
• Satellite data applications will require collaboration across disciplines
Aerosol Species Monitoring Growth (1999-03)
• Daily valid station counts for sulfate has increased from 50 to 350
• About 250 sites sample every 3rd day, 350 sites every 6th day
Nitrate
Sulfate Sites 99-03
IMPROVE + EPA Sulfate
Origin of Fine Dust Events over the US
Gobi dust in springSahara in summer
Fine dust events over the US are mainly from intercontinental transport
Fine Dust Events, 1992-2003ug/m3
Asian Dust Cloud over N. America
On April 27, the dust cloud arrived in North America.
Regional average PM10 concentrations increased to 65 g/m3
In Washington State, PM10 concentrations exceeded 100 g/m3
Asian Dust 100 g/m3
Hourly PM10
During the trans-Pacific transit the dust plume was also tracked independently by Washington University and University of Wisconsin using GMS-5 and GOES-9 geostationary satellites, respectively.
GMS-5 Image of Dust over the Central Pacific on April 24
GOES-9 images of Dust over the Central Pacific on April 24
Supporting Evidence: Transport Analysis
Satellite data (e.g. SeaWiFS) show Sahara Dust reaching Gulf of Mexico and
entering the continent.
The air masses arrive to Big Bend, TX form the east (July) and from the west
(April)
Sahara PM10 Events over Eastern USMuch previous work by Prospero, Cahill, Malm, Scanning the AIRS PM10 and IMPROVE chemical
databases several regional-scale PM10 episodes over the Gulf Coast (> 80 ug/m3) that can be attributed to Sahara.
June 30, 1993
The highest July, Eastern US, 90th percentile PM10 occurs over the Gulf Coast ( > 80 ug/m3)
Sahara dust is the dominant contributor to peak July PM10 levels.
July 5, 1992
June 21 1997
Seasonal Average Fine Soil (VIEWS database, 1992-2002)
• Fine soil concentration is highest in the summer over Mississippi Valley, lowest in the winter• In the spring, high concentrations also exists in the arid Southwest (Arizona and Texas)• Evidently, the summer Mississippi Valley peak is Sahara dust while the Spring peak is from local sources
Mystery Winter Haze:Natural? Nitrate/Sulfate? Stagnation?
Mystery not Solved, too Complicated, Calls for Multidisciplinary Community Analysis
Contributed by the FASNET Community, Sep. 2004
Correspondence to R Husar , R Poirot
Coordination Support by
Inter-RPO WG Fast Aerosol Sensing Tools for Natural Event Tracking, FASTNETNSF Collaboration Support for Aerosol Event Analysis
NASA REASON CoopEPA -OAQPS
AIRNOW PM25 - February
Midwest HazeCam ImagesJan 27-Feb 3, 2005
• The images were part of the Midwest HazeCam Console of FASTNET project.
Seasonal PM25 by Region
FRM PM25 Monthly Concentration
• Monthly average FRM PM25 are shown as circle and contour (Blue: 0; Red: 25 g/m3)• The Feb/Mar peak is clearly evident in the Midwest region; also in January• Hence, there is some deviation in peak location and time among the networks
JAN FEB MAR APR
MAY JUN JUL AUG
SEP OCT NOV DEC
EPA AIRS 1999-2002
Seasonal Nitrate, VIEWS 2000-2004
JAN
DEC
FEB MAR APR
MAY JUN JUL AUG
SEP OCT NOV
Eastern US Nitrate - Daily Average
‘Nitrate Events’
Smoke over the Eastern US
• Major contributor to aerosol Events• Key tracers are aerosol organics
Kansas Agricultural Smoke, April 12, 2003
Fire Pixels PM25 Mass, FRM65 ug/m3 max
Organics35 ug/m3 max
Ag Fires
SeaWiFS, Refl SeaWiFS, AOT Col AOT Blue
Informatics:The Researcher/Analyst’s Challenge
“The researcher cannot get access to the data;if he can, he cannot read them; if he can read them, he does not know how good they are;and if he finds them good he cannot merge them with other data.”
Information Technology and the Conduct of Research: The Users ViewNational Academy Press, 1989
These resistances can be overcome through a distributed system that catalogs and standardizes the data and provides
tools for data manipulation and analysis.
Smoke Plumes over the Southeast
• Satellite detection yields the origin and location is the shape of smoke plumes
• The influence of the smoke is to increase the reflectance ant short wavelength (0.4 mm)
• At longer wavelength, the aerosol reflectance is insignificant.
R 0.68 m
G 0.55 m
B 0.41 m
0.41 m
0.87 m
•
‘Natural’ Aerosols: Biomass Smoke
Satellite data show numerous small fires in the Southeast
The type of these fires is not known. Prescribed/agricultural burning? Wild fires?
Issue: How does one space-time aggregate such a highly variable emission?
PM2.5 conc., smoke pattern and SeaWiFS image of plumes originating from Kentucky, Nov 15, 1999.
More details here here
Nov 15, 1999
Oct 5, 1998 Oct 5, 1998
Smoke Plumes Smoke Plumes
Regional Smoke?
Seasonal Pattern of Dust Baseline and Events
• The dust baseline concentration is has a 5x seasonal amplitude from 0.2 to 1 ug/m3• The dust events (determined by the spike filter) occur in April/May and in July• The April/May and July dust peaks are due to the events
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
01/01/92 02/20/92 04/10/92 05/30/92 07/19/92 09/07/92 10/27/92 12/16/92
EventsBaselineTotal