obtaining routine vertical profiles of aerosol distribution worldwide: why, how, and what to do with...

Obtaining routine vertical profiles of aerosol distribution worldwide:why, how, and what to do with all that data

Judd WeltonGEST/UMBC & Code 912

CALIPSOCloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations

Collaborators:

MPLNET: James Campbell, Tim Berkoff,Jim Spinhirne, Brent Holben, Si-Chee Tsay

GLAS: Dennis Hlavka, Bill Hart, Steve Palm,Ash Mahesh, Jim Spinhirne

CALIPSO: Chris Hostetler, Mark Vaughan, Ali Omar,Dave Winker, John Reagan, Tad Anderson

… and a long list of other folks at NASA Centers:GSFC, LaRC, and Ames. As well as other governmentagencies such as ARM and NOAA. Finally, manyuniversity research groups around the world.

Outline:

• Introduction: why do we care about aerosols & their vertical distribution?

• How to measure aerosol vertical distributions? - Lidar: what is it? how to use it to study aerosols, and what can be done now to get routine global observations?

• MPLNET, GLAS, CALIPSO: what are they?

• Recent results from MPLNET, expected results from GLAS and CALIPSO, and how they can work together

• Conclusion

EARTH SCIENCE ENTERPRISE MISSION, GOALS, AND OBJECTIVES

Develop a scientific understanding of the Earth system and its response to natural and human-induced changes to enable improved prediction of climate, weather, and natural hazards for present and future generations.

1. ScienceObserve, understand, and model the Earth system to learn how it is changing and the consequences for life on Earth.

2. ApplicationsExpand and accelerate the realization of economic and societal benefits from Earth science, information, and technology.

3. TechnologyDevelop and adopt advanced technologies to enable mission success and serve national priorities.






One Planet






One Planet

Land Atmosphere Water






One Planet


Gases Clouds Aerosols Plasmas






One Planet



… and it continues ...

Aerosols:• Dry or aqueous particles suspended in the atmosphere• Size range:

• Aitken < 0.1 m• fine mode < 1 m• coarse mode > 1 m

• Origins:• nucleation

• formation of sulfate• typically Aitken sized

• sublimation• deposition of nitrate onto sea-salt• fine - coarse mode sizes

• coagulation• merging of two aerosol droplets• fine - coarse mode sizes

• surface matter• sea-salt, dust, soot• fine - coarse mode sizes

• Caused by natural and anthropogenic sources• Particle Shapes vary:

• spheres (sulfate)• irregular (dust)

• Lifetimes & Transport:• vary depending upon origin, convection mechanism, size, hydroscopicity• typically days to weeks, volcanic aerosols can be years• can transport long distances (around the world)

Aerosols:• Dry or aqueous particles suspended in the atmosphere• Size range:

• Aitken < 0.1 m• fine mode < 1 m• coarse mode > 1 m

• Origins:• nucleation

• formation of sulfate• typically Aitken sized

• sublimation• deposition of nitrate onto sea-salt• fine - coarse mode sizes

• coagulation• merging of two aerosol droplets• fine - coarse mode sizes

• surface matter• sea-salt, dust, soot• fine - coarse mode sizes

• Caused by natural and anthropogenic sources• Particle Shapes vary:

• spheres (sulfate)• irregular (dust)

• Lifetimes & Transport:• vary depending upon origin, convection mechanism, size, hydroscopicity• typically days to weeks, volcanic aerosols can be years• can transport long distances (around the world)

Land use processes and surface conditions directly relate to the production of certain types of aerosols

Example of aerosol interaction with other aspects of the earth system

Aerosols cont:Why do we care about them?


• They have a direct effect on climate• scatter and absorb radiation• primarily fine and coarse mode• change the amount of sunlight reaching the earth’s surface & what is reflected back to space• absorption can alter heating budget

• They have an indirect effect on climate• interaction with clouds• create new clouds or modify existing ones• change cloud albedos• can effect precipitation

From IPCC 2001 3rd Assessment Report






Above graph contains global mean forcing values ….Regional forcing can be much higher:

Northern Indian Ocean INDOEX Results (direct+indirect):TOA Forcing: -5 to -15 W/m2Surface Forcing: -15 to -35 W/m2Atmosphere Forcing: 10 to 25 W/m2(Ramanathan et al, JGR, 2001):





• Indirect effect is another example of aerosols interacting with other parts of the earth system


Above graph contains global mean forcing values ….Regional forcing can be much higher:

Northern Indian Ocean INDOEX Results (direct+indirect):TOA Forcing: -5 to -15 W/m2Surface Forcing: -15 to -35 W/m2Atmosphere Forcing: 10 to 25 W/m2(Ramanathan et al, JGR, 2001):



Lets go one further, and say:“… natural and anthropogenic hazards …”




• Human Health Hazards

• Traffic Hazards




Human Health Hazards:

• Small aerosols can enter the lungs

• EPA standard from 1997: particles smaller than 2.5 m as cutoff for regulation• Pope et al., JAMA, 2002: Mortality rates & long-term exposure to fine particulate air pollution

• Each 10 g/m3 elevation in < 2.5 m aerosol concentration associated with:4% increased risk of all-cause mortality6% increased risk of cardiopulmonary mortality8% increased risk of lung cancer mortality

• Conclusion: long-term exposure to small aerosols is important risk factor• Caveat: heavily focused on “urban” type aerosols

• Aerosols, especially dust, can also carry microbes long distances• Griffin et al., Aerobiologia, 2001:

• bacteria-like & virus-like particle counts in the US Virgin Islands greater during African dust events relative to clear periods




Human Health Hazards:

• Small aerosols can enter the lungs

• EPA standard from 1997: particles smaller than 2.5 mm as cutoff for regulation• Pope et al., JAMA, 2002: Mortality rates & long-term exposure to fine particulate air pollution

• Each 10 mg/m3 elevation in < 2.5 mm aerosol concentration associated with:4% increased risk of all-cause mortality6% increased risk of cardiopulmonary mortality8% increased risk of lung cancer mortality

• Conclusion: long-term exposure to small aerosols is important risk factor• Caveat: heavily focused on “urban” type aerosols

• Aerosols, especially dust, can also carry microbes long distances• Griffin et al., Aerobiologia, 2001:

• bacteria-like & virus-like particle counts in the US Virgin Islands greater during African dust events relative to clear periods

Human health issues and ...

Deposition of dust over oceans:• can effect growth of certain types of phytoplankton & algae• impacts the health of coral reefs

• both are examples of aerosols interacting with other aspects of the earth system




• Human Health Hazards

• Traffic Hazards




Traffic Hazards:

• Reduced visibility creates hazards to both air and ground transportation

• USA Today, AP, 2002: Multiple highway accidents in California blamed on dust storms

• March 13 ,2002 - 2 seven car pile ups on I-15

• MSNBC, AP, 2002: Smoke from Quebec forest fires effects air traffic in NY

• July 7, 2002 - all major airports report “smoke and haze visibility restrictions of two miles”

• Prospero et al, Eos Trans., 1999: Kennedy plane crash in July 1999 attributed in part to haze

• large-scale aerosol event occurred at same time, aerosols were at altitudes capable of effecting Kennedy’s visibility on approach for landing

• Ingestion of aerosols into aircraft engines has also been a concern

New York City Skyline on July 7, 2002

Aerosols cont:

If all those reasons don’t matter:

How about “poor air quality makes the atmosphere look dirty and ugly”

standard of living!

Why do we care about them?

Aerosols cont:

If all those reasons don’t matter:

How about “poor air quality makes the atmosphere look dirty and ugly”

standard of living!

Of course, it makes pretty sunsets so I guess “who cares”

Why do we care about them?






One Planet




Aerosols cont:Ok we care about aerosols, but why their vertical distribution?

• Aerosol’s altitude determines where in the atmosphere they scatter and absorb sunlight• Height of absorbing aerosols effects heating rate profile and analysis of some satellite data• Aerosol height is required to determine altitude at which radiative forcing occurs

• Vertical distribution is tied to how aerosols transport from source region to elsewhere• In order to transport long distances, aerosols must get high enough to offset their settling and removal by other processes along the trip• To have direct health effects, transported aerosols must eventually reach the surface

Column Radiation Meas.

Surface Sampling

Yes, dust arrives to Caribbean & US Dust blows from Africa,across Atlantic

Aerosols cont:Ok we care about aerosols, but why their vertical distribution?

• Aerosol’s altitude determines where in the atmosphere they scatter and absorb sunlight• Height of absorbing aerosols effects heating rate profile and analysis of some satellite data• Aerosol height is required to determine altitude at which radiative forcing occurs

• Vertical distribution is tied to how aerosols transport from source region to elsewhere• In order to transport long distances, aerosols must get high enough to offset their settling and removal by other processes along the trip• To have direct health effects, transported aerosols must eventually reach the surface

Column Radiation Meas.

Surface Sampling

Yes, dust arrives to Caribbean & US Dust blows from Africa,across Atlantic

But what happens along the way? How does it transport?

So what do we really want to know about aerosol vertical distribution?• detect the presence of aerosols• determine their altitude• calculate their optical properties• deduce their concentration• determine if they interact with clouds and/or if they reach the surface• figure out what type of aerosols are present• find out how the aerosols got to a particular location and where they will go afterwards


Global

Regional

Regional

Regional

Case Studies

Which type of study to choose?

• Global observations• planetary climate• seasonal/yearly studies• regional connections

• Regional studies• regional climate• seasonal/yearly studies• begin to connect case studies to big picture & assess their relevance

• Case studies• can analyze aerosol in much more specific detail• often best way to get point across, but should be done with relevance to bigger picture in mind


Global

Regional

Regional

Regional

Case Studies

Which type of study to choose?

• Global observations• planetary climate• seasonal/yearly studies• regional connections

• Regional studies• regional climate• seasonal/yearly studies• begin to connect case studies to big picture & assess their relevance

• Case studies• can analyze aerosol in much more specific detail• often best way to get point across, but should be done with relevance to bigger picture in mind

Routine, long-term, globally distributed measurements with enough spatial and temporal resolution to be of use to regional and case studies are most desired

The IPCC 2001 3rd assessment report:need development and support of systematic ground-based measurements, in particular, a dramatic increase in systematic vertical profile measurements






One Planet




What instruments can measure aerosol vertical distribution?


• Direct sampling from aircraft• Direct sampling from sonde• Lidar



What is best for global, routine, long-term monitoring?




• Aircraft• best platform for direct sample• problems: not routine, not long-term, difficulty with ambient meas.





• Sondes• routine - yes, long-term - yes• problems: hard to do aerosol sampling, same ambient issues,

and resource is lost upon sampling





• Sondes• routine - yes, long-term - yes• problems: hard to do aerosol sampling, same ambient issues,

and resource is lost upon sampling• Lidar

• routine - yes, long-term - yes• lidar can provide most of the desired data listed previously

What is a lidar?

• an instrument that sends pulses of laser light into the atmosphere to measure an atmospheric parameter’s vertical structure• many types of lidar exist - here we only discuss those used to measure aerosols (and clouds)

Ground

Boundary Layer

Molecular Scattering

Elevated Layer

• Lidar systems:• Backscatter• Raman• DIAL• Hyperspectral

Laser

What is a lidar?

• an instrument that sends pulses of laser light into the atmosphere to measure an atmospheric parameter’s vertical structure• many types of lidar exist - here we only discuss those used to measure aerosols (and clouds)

Ground

Boundary Layer


Elevated Layer

• Lidar systems:• Backscatter• Raman• DIAL• Hyperspectral

Laser Receiver

PNRB(r) =C βM(r)+βP(r)[ ]TM2(r)TP

2(r)TO2(r)

Si(r) =σ i(r)βi (r)

Si =4π

ωoPi(180)

Ti2(r) =exp−2 σi( ′ r )d ′ r

rL

r

∫⎡ ⎣

⎤ ⎦

The Backscatter Lidar Equation:

Raw signals are background subtracted and normalized to range, energy. Any other instrumentEffects are also corrected for. Resulting equation is an uncalibrated lidar signal:

where

C (extinction, and (backscatter) are unknown. We can model molecular and ozone terms, particulate and are what we want to determine. To solve equation we must know the relationship between the two.

What we want is global, routine, long-term monitoring to start now

• Lidar requirements• exists• proven, relatively simple design• capable of deployments for global observation - cost implication• eye-safe


• Lidar requirements• exists• proven, relatively simple design• can be deployed for global observations - cost implication• eye-safe

• Backscatter lidars are easiest to build and can meet the above requirements• more limited data set• form basis for future deployment of more sophisticated lidars




What we want to know about aerosol vertical distribution:• detect the presence of aerosols• determine their altitude• calculate their optical properties• deduce their concentration• determine if they interact with clouds and/or if they reach the surface• figure out what type of aerosols are present• find out how the aerosols got to a particular location and where they go afterwards

Ground

Boundary Layer



2(r)TO2(r)


2(r)TO2(r)

Sa(r) =σ a(r)βa(r)

The Backscatter Lidar Equation: Ground-based example

Ground

Boundary Layer



2(r)TO2(r)


Ground

Boundary Layer


… But a co-located sunphotometer can provide aerosol optical depth (AOT): P

Sa =σa

βa

Sa =τp

βa( ′ r )d ′ r 0

top

∫

Assume Sa is constant throughout the boundary layer:

A modified version of the solution uses the sunphotometer AOT as a constraint.The normal process is iterated until successive values of Sa agree:

Solving for backscatter and extinction

Standard Fernald [Appl. Opt., 1984] type solution used,


2(r)TO2(r)

TP2(r) =exp−2τP[ ] r > boundary layer


Ground

Boundary Layer


co-located sunphotometer provides aerosol optical depth (AOT): P Calculate Calibration parameter: C

Calibrating the lidar


2(r)TO2(r)

Sa =σa

βa


Sa =τp

βa( ′ r )d ′ r 0

top

∫

Ground

Boundary Layer


Net Results:

• Aerosol height can be determined

• MPL can be calibrated

• backscatter and extinction profiles can be calculated, along with an average Sa, for the aerosol layer

• extinction profile will integrate to the correct AOT, however the extinction value at any given altitude within the layer may be under-or-over- estimated due to assumption of a constant Sa




• Two options• ground-based network• space-based platform

E.J. Welton, Goddard Earth Sciences & Tech. Center NASA/GSFC, Code 912

Determining Optical Depth and Extinction from Satellite Lidars: The Missing Link

--> Extinction-to-Backscatter Ratio (Sa)

Much more difficult to get co-located AOT meas.

Ground

Boundary Layer


Elevated Layer

Determining Optical Depth andExtinction: Comparison betweenboundary and elevated layers

Conclusion:Sometimes can directly calculate opticaldepth, extinction, and S for elevatedlayers -- NEVER for boundary layer

If cannot directly calculate optical depth, need to guess S

Default Scenario: Lookup Table for Sa

• GLAS Index Functions based on:• 4, 7, 11, 13 based on model from Ackermann, 1998• 12 based on Welton et al., 2000

• Current Efforts to improve knowledge of Sa:• MPL-Net:

• field exps: target key regions/aerosols• CALIPSO Science Team:

• John Reagan, compilation of all meas.• Tad Anderson, in-situ meas. of Sa• Ali Omar, calculate Sa from AERONET data

• Several other research groups worldwide


• Different lookup table for boundary layer and elevated layers

• Different lookup table for each month of the year






One Planet




The Micro-pulse Lidar Network : (MPL-Net)

E.J. Welton, UMBC/GEST - NASA/GSFC, Code 912 MPL-Net: http://virl.gsfc.nasa.gov/mpl-net/

Mission: Long-term, world-wide observations of aerosol and cloud vertical structure using common instrument/data processing

Funding: NASA Earth Observing System (sites/field exp), NASA SIMBIOS Program (ocean cruises)

Activities:• Setup new MPL-Net funded sites, co-located with AERONET sunphotometers (and BSRN radiometers)• Incorporate existing Atmospheric Radiation Measurement (ARM) Program MPL sites• Partner with other independent research groups interested in MPL measurements (federated network)• Participate in field experiments and research cruises (connection to regional studies)

Satellite Lidar Calibration/Validation: GLAS - ICESat (2002), CALIPSO - ESSP3 (2004)

NASA Site

Proposed NASA Site

ARM Site

Nat. Inst. Polar Res. Japan

Proposed NRL Site

Field Experiment

Ship Cruise

• Micro-pulse Lidar Systems (MPL)• compact & semi-autonomous• 523 nm wavelength• PRF 2500 Hz• eye-safe, output energy in µJ• small FOV, no multiple scattering

Transceiver: 20cm Cassegrain Telescope on topLaser Head, Detector, & Optics below

Scalar Unit:Data Binning at 30, 75, 150, 300 m res

Laser Power Supply:1 W Nd:YLF Laser Diode(Doubled to 523nm on Head)

Laptop Computer:Data Acquisition & Storage (1 min res)


MPL-Net Data Products

* uncertainties calculated for all data products listed below, except Level 0* data files available from MPL-Net web-site for all operational products, all file formats in NetCDF* user can browse through images of all operational data products on web-site

• Level 0.0: Raw data, automated, download to GSFC and archived, but not available on the web-site (operational)

• Level 1.0: Real-time Normalized Relative Backscatter Signals (operational)

• Level 1.5a: Real-time Aerosol Height & Extinction Profile, Not Quality Assured (operational)

• Level 1.5b: Real-time Multiple Cloud Heights, Not Quality Assured (not operational, testing underway)

• Level 2.0a: Aerosol Height & Extinction Profile, Quality Assured (operational)

• Level 2.0b: Multiple Cloud Heights, Quality Assured (not operational, no testing yet)

• Level 3.0a: Continuous, Gridded, Multiple Cloud and Aerosol Data Products (not operational, testing on field exps)




Satellite Lidar Projects:

• Platform• ICESat, launch date 2002 ? … 8)

• Mission• Polar Altimetry• Cloud and Aerosol Profiler

• Specs• 532 and 1064 nm lidar• 40 pulses/second, 76m vertical resolution

• Key Data Products• cloud & aerosol layer heights, 0 - 40 km• layer optical depths, extinction profiles

• Development and Science Teams (Lidar only)• Algorithm Development: GSFC Code 912• Science Team: GSFC Code 912

• Platform• ESSP-3, launch date 2004• formation fly with CloudSat & Aqua

• Mission• Cloud and Aerosol Profiler

• Specs• 532 and 1064 nm lidar• 20 pulses/second, vertical res. varies• polarization meas. at 532 nm

• Key Data Products (still under development)• cloud & aerosol layer heights, 0 - 40 km• layer optical depths, extinction profiles

• Development and Science Teams• Algorithm Development: LaRC• Science Team: LaRC and International

MPL-Net Data Products

* uncertainties calculated for all data products listed below, except Level 0* data files available from MPL-Net web-site for all operational products, all file formats in NetCDF* user can browse through images of all operational data products on web-site

• Level 0.0: Raw data, automated, download to GSFC and archived, but not available on the web-site (operational)

• Level 1.0: Real-time Normalized Relative Backscatter Signals (operational)

• Level 1.5a: Real-time Aerosol Height & Extinction Profile, Not Quality Assured (operational)

• Level 1.5b: Real-time Multiple Cloud Heights, Not Quality Assured (not operational, testing underway)

• Level 2.0a: Aerosol Height & Extinction Profile, Quality Assured (operational)

• Level 2.0b: Multiple Cloud Heights, Quality Assured (not operational, no testing yet)

• Level 3.0a: Continuous, Gridded, Multiple Cloud and Aerosol Data Products (not operational, testing on field exps)


Real-time MPL-Net Data Products:

Level 1.0 - lidar signal

E.J. Welton GEST/UMBC NASA/GSFC/912

Real-time MPL-Net Data Products:

Level 1.0 - lidar signal

Level 1.5a - extinction profiles correlated with AERONET data

• uncertainties are calculated for all data products

E.J. Welton GEST/UMBC NASA/GSFC/912

345.0 345.1 345.2 345.3 345.4 345.5 345.6 345.7 345.8 345.9 346.0

2019181716151413121110

9876543210

Day of Year (UTC)

Altitude (km)

0.0 0.2 0.3NRB Signals


Example Level 1.5b Results: ARM SGP Dec 11, 2001 (Multiple Cloud Heights)

Example Level 1.5b Results: ARM SGP Dec 11, 2001 (Multiple Cloud Heights) (Data from existing ARM cloud height algorithm)

False Positives


121 122 123 124 125

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987654321

Day of Year (UTC)

Altitude (km)

0.00 0.25 0.50 0.75 1.00NRB Signals

1.00

0.75

0.50

0.25

0.00

GSFC May 1 - 4, 2001: NRB Signals

Level 2.0 Calibration Values

Example Level 3.0 Results: GSFC May 1 - 4, 2001

121 122 123 124 125

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Day of Year (UTC)

Altitude (km)

0.00 0.25 0.50 0.75 1.00NRB Signals

1.00

0.75

0.50

0.25

0.00

GSFC May 1 - 4, 2001: NRB Signals

121 122 123 124

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Day of Year (UTC)

Altitude (km)

0.0 0.1 0.2 0.3 0.4Extinction (1/km)

0.5

0.4

0.3

0.2

0.0

0.1

Extinction Profiles (1/km)

Aerosol Optical Thickness

Black: MPL-NetRed: AERONET

Validation of MPL-Net Data Products (primarily extinction):

Major effort on our part

Essential before using MPL-Net data to validatesatellite-based lidar systems

Previous validation efforts (pre MPL-Net):

• ACE-2 (1997): NASA Ames Airborne Tracking Sunphotometer (AATS)

• INDOEX (1999): Co-located nephelometer/PSAP measurements (NOAA PMEL)

Recent/Ongoing validation efforts:

• PRIDE (2000): NASA Ames Airborne Tracking Sunphotometer (AATS)

• SAFARI (2000): NASA Ames Airborne Tracking Sunphotometer (AATS) Cloud Physics Lidar (CPL)

• ACE-Asia (2001): NASA Ames Airborne Tracking Sunphotometer (AATS) Co-located nephelometer/PSAP measurements (NOAA PMEL)

Airborne nephelometer/PSAP measurements (Univ Washington)

AATS - B. Schmid, P. Russell, J. Redemann, J. Livingston (NASA Ames)NOAA PMEL - T. Bates, P. QuinnUniversity of Washington - T. Anderson, S. MasonisCPL - M. McGill, D. Hlavka, B. Hart (GSFC)

Data from PRIDE 2000:Livingston et al., 2002

Data from SAFARI 2000:Schmid et al., 2002(includes comparions withResults from the ER-2 basedCloud Physics Lidar -CPL -Also based in 912)

Data from ACE2 (1997):Welton et al., 2000

Examples of Validation of MPL Extinction Profiles: Comparisons with the NASA Ames Airborne Tracking Sunphotometer (AATS)

Some Examples of Science and applications:

• Using MPL data to characterize aerosol regionally• put together results from different regions in the network and we build global view

• Tying MPLNET results together with aerosol modeling and satellite data to study transport

• Using MPLNET as a ground calibration/validation tool for GLAS and CALIPSO

Aerosol vertical structure over the Northern Indian Ocean? Data from INDOEX 1999 --- Welton et al., JGR, 2002

Aerosol extinction, humidity, and temperature according to keyair mass trajectories during the experiment

Aerosol vertical structure over the Northern Indian Ocean? Data from INDOEX 1999 --- Welton et al., JGR, 2002

Sa values recorded during the experiment in relationTo other measurements over the ocean

1 2 3 4 5 6 7 8 9 10 11 12

1211

10

98

7

65

4

32

1

1211

10

98

7

65

4

32

1

Month

Altitude (km)

0.00 0.05 0.10 0.15 0.20Aerosol Extinction (1/km)

First Year Results from GSFC site: Seasonal StudyApr 2001 - July 2002

(using level 1.5a results, not screened for bad data)

Monthly averages of aerosol extinction profiles

First Year Results from GSFC site: Seasonal Study Apr 2001 - July 2002

Monthly averages of aerosol results from MPLNET & AERONET*

* AERONET results from 2001 climatology



MPL-Net Validation Efforts for Satellite Lidar Projects:

MPL-Net can be used for the following:

Post-launch Validation:• cloud and aerosol heights• layer optical depths and extinction profiles

Help tackle the extinction-to-backscatter ratio (Sa) problem• improve determination of Sa for specific aerosol types & geographic regions• assess utility of using aerosol transport models to help infer aerosol type

• result then used to calculate Sa

Issues Involved in Validating Satellite Lidar Using Ground-based Lidar: Example from SAFARI: Comparison between MPL and CPL

Degree of Horizontal and Temporal Homogeneity is a key factor

Same applies to comparisons between Lidar and Ground/Airborne Sunphotometers(ACE-2, PRIDE, SAFARI, ACE-Asia, CLAMS)






Help tackle the extinction-to-backscatter ratio (Sa) problem• improve determination of Sa for specific aerosol types & geographic regions• assess utility of using aerosol transport models to help infer aerosol type


MPLNET Results from Various Field Experiments are being used to help determine Sa Values

Southern Africa:Biomass, pollution, somedust

Caribbean:Dust, sea-salt, somepollution

China:Dust, some pollution

Pacific, Yellow Sea, Sea of Japan:Sea-salt, dust, pollution






Help tackle the extinction-to-backscatter ratio (Sa) problem• improve determination of Sa for specific aerosol types & geographic regions• assess utility of using aerosol transport models to help infer aerosol type*


* closely tied to using lidars to study aerosol transport, example shown

Default Sa Lookup Table: Aerosol type required

Transport models may help identify aerosol type


Comparisons between MPLNet observations and GOCART Results:

Early April 2001 - Massive Dust Storms in Asia

MPL Systems Operating as part of MPLNet in April 2001

GSFC: MPL-Net SiteSGP and NSA: ARM SitesShip: R/V Ronald Brown (ACE-Asia/SIMBIOS)Dunhuang: China, ACE-Asia (S. Tsay)

GOCART Dust Sources:Sah: Saharan T: TaklamakanM: Middle East G: Gobi D: Distrubed Soils(GOCART Data courtesy P. Ginoux, M. Chin)

GSFC

SGP

NSA

Dunhuang Ship

SahM T G

Image by R. Husar, Washington Univ.

April 7, 2001

99.00 99.25 99.50 99.75 100.00

16

14

12

10

8

6

4

2

Day of Year (UTC)

Altitude (km)

0.00 0.03 0.05 0.08 0.10NRB Signal

100.00 100.25 100.50 100.75

14

12

10

8

6

4

2

0

Day of Year (UTC)

Altitude (km)

0.00 0.03 0.05 0.08 0.10NRB Signals

Dun Huang, ChinaApril 9, 2001

R/V Ron BrownSea of JapanApril 10, 2001

and ……..

MPL-Net Level 1.0 Data for several sites during April 2001

GOES Imagery April 13, 2001 at 1400 UTC (image courtesy A. Chu and S. Tsay 913)

99.00 99.25 99.50 99.75 100.00

16

14

12

10

8

6

4

2

Day of Year (UTC)

Altitude (km)

0.00 0.03 0.05 0.08 0.10NRB Signal

100.00 100.25 100.50 100.75

14

12

10

8

6

4

2

0

Day of Year (UTC)

Altitude (km)

0.00 0.03 0.05 0.08 0.10NRB Signals

Dun Huang, ChinaApril 9, 2001

R/V Ron BrownSea of JapanApril 10, 2001

ARM Southern Great PlainsOklahomaApril 13, 2001

and ……..

MPL-Net Level 1.0 Data for several sites during April 2001

103.00 103.25 103.50 103.75 104.00

14

12

10

8

6

4

2

Day of Year (UTC)

Altitude (km)

0.000 0.125 0.250NRB Signals

GSFC Data: April 13-14, 2001 (First Observation of Asian Dust at GSFC)

103.0 103.2 103.4 103.6 103.8 104.0 104.2 104.4 104.6 104.8 105.0

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Day of Year (UTC)

Altitude

0.00 0.25 0.50 0.75 1.00NRB Signal (Uncalibrated Signal)

April 14, 2001

GSFC AERONET AOD and Angstrom Exponent: April 13-14, 2001

April 13, 2001

Discontinuity in AERONETdata at same time as appearanceof aerosol layer at 5-6 km

AOD increases by ~ 0.05

Angstrom Exponent drops below1, indicating sudden presence of large particles

GSFC Data: April 13-14, 2001 (First Observation of Asian Dust at GSFC)

103.0 103.2 103.4 103.6 103.8 104.0 104.2 104.4 104.6 104.8 105.0

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Day of Year (UTC)

Altitude

0.00 0.25 0.50 0.75 1.00NRB Signal (Uncalibrated Signal)

April 14, 2001

GSFC AERONET AOD and Angstrom Exponent: April 13-14, 2001

April 13, 2001

Discontinuity in AERONETdata at same time as appearanceof aerosol layer at 5-6 km

AOD increases by ~ 0.05

Angstrom Exponent drops below1, indicating sudden presence of large particles

a

Ship: Sea of Japan April 10

GSFC: April 13

Comparisons between results from MPLNET and GOCART

* GOCART still showsmore Saharan dust thanall 3 of these sources

Conclusion:

• Aerosols are an important part of the earth system for studies of climate, health, and traffic hazards• Determining aerosol vertical distribution is required for a complete understanding of their effects and how they transport

Conclusion:


• Lidars are capable of providing information on aerosol vertical distribution• At this time: the simplest type, the backscatter lidar, is best suited for coordinated global, routine, long-term measurements

Conclusion:



• Projects such as MPLNET, GLAS, and CALIPSO are capable of generating useful data on global, regional, and even case study scales

Conclusion:




• When (or if) GLAS and CALIPSO begin data collection we will enter a new stage of lidar analysis

• large data sets, massive spatial scales, and seemingly unending temporal coverage• how to handle all that data, and work with it, is the focus of much thought

Conclusion:






• To the future: if (when) these types of projects are successful and useful, then serious thought should be given to implementing more sophisticated lidars into global measurement strategies

Conclusion:






• To the future: if (when) these types of projects are successful and useful, then serious thought should be given to implementing more sophisticated lidars into global measurement strategies

• what if the data from these more simple lidars turns out to be sufficient to answer the big questions (aerosol only)? or worse - no uses the data?

obtaining routine vertical profiles of aerosol distribution worldwide: why, how, and what to do with...

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earth system

natural hazards

mission success

improved prediction

humaninduced changes

scientific understanding

future generations

national priorities