An Interagency Research Initiative for Ground-Based Lidar Profiling of Tropospheric Ozone and Aerosol

CENRSAir Quality Research Subcommittee

Nov. 17, 2011Washington, DC

Mike Newchurch1, Jay Al-Saadi2, R. J. Alvarez3, John Burris4, John Hair5, Russell DeYoung5, Mike Hardesty3, Shi Kuang1, A. O. Langford3, Stuart McDermid6,Tom McGee4, Christoph Senff3, Jim Szykman7

1UAHuntsville 2NASA/HQ3NOAA/ESRL 4NASA/GSFC5NASA/LaRC 6NASA/JPL 7USEPA

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I. Motivation for prototype ozone lidar network measurements

•PBL Processes, especially those involving the diurnal pumping of the boundary layer, are the scientific key to understanding regional/local interactions resulting in surface ozone. Understanding the spatio-temporal complexity of these physical and chemical processes demands observations at high spatial (initially vertical) and temporal resolution.•Ozonesondes are extensively used in various atmospheric chemistry studies because of their low upfront cost and well-characterized behavior. However, the whole process for a sonde launch typically requires four hours. And four-hour ozonesonde resolution is prohibitively expensive. We therefore consider lidars to provide the necessary spatial and temporal resolution.•GEO-CAPE will measure tropospheric gases and aerosols at ~8km and hourly resolution. Vertical resolution is on the order of 5-10km in the troposphere. This vertical resolution is inadequate to resolve laminar structures that characterize tropospheric ozone and aerosols. Furthermore, GEO-CAPE information content in the PBL will likely be inadequate to resolve the processes responsible for air quality variability. We seek, therefore, to understand how the spaceborne measurements may be complemented with a ground-based measurement system.•Air quality models are critical for supporting important policy decisions. Unfortunately, the general lack of high-resolution observations aloft limits the evaluation of air-quality models. The lidar profiling measurements can make significant contributions in evaluating air-quality models and improving their simulation and forecasting capabilities.

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Comparison of the techniques for ozone observation

a For OMI tropospheric ozone retrieval [Liu et al. 2010], [Worden et al. 2007]. b For ground-based only. The airborne lidar system can measure ozone with a 600-m spatial resolution, e.g., [ Langford et al. 2011]. c For ground-base system, e.g., Sunnesson et al.1994; Proffitt and Langford 1997; Kuang et al. 2011. The temporal resolution is strongly related to the retrieval uncertainty. Generally longer integration time will reduce the uncertainty arising from statistical error. d The estimated cost is based on $800/launch and launching 6 sondes every day.

Ozonesonde Ground-based lidar Sun-synchronousSatellite (OMI) a

Geostationary satellite (GEO-CAPE)

Vertical resolution ~100m 100-1000m 10-14km 5-10 km

Spatial coverage Point Point b Global Land and coastlines over 10-60oN band

Spatial resolution N/A N/A b 13X48km at nadir 8x8km

Temporal resolution Typically 1 week, max 4 hr 2-30 min c Typically 1 day 1 hr

Meas. uncertainty 10% Typically 10% at the near range and 20% at the far range

6%-35%

Cost Typically $40k/year, max $1,752k/year d

Goal: <$300k/year for fixed station

high high

Major strength well-characterized, low up-front cost, good vertical resolution,

High temporal resolution, low cost for frequent routine measurement

global coverage , high accuracy on total column retrieval

High spatio-temporal resolution relative to sun-sync satellite

Major weakness Low temporal resolution Unable to measure ozone above thick cloud, higher up-front cost relative to sonde

Low vertical resolution (particularly limited to resolve PBL)

Low vertical resolution (particularly limited to resolve PBL)

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ozonesonde

Lidar ozone curtain with10-minute resolution

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O3 measurements with 4-hour temporal resolution

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II. Air-Quality Lidar-Network Working Group (AQLNWG)

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Partners

Agency rolesNASA: Historical funding of several lidar programs and GEO-CAPE satellite program.

NOAA: Funding of ESRL lidar group, AQ campaigns, NESDIS satellite programs.

EPA: Principal user and policy driver.

NASA R&A initiated and invited participation in AQLNWGName the members here?

FundingNASA providing funding to adapt existing instruments, begin acquiring data, archive data, and facilitate data useNOAA and EPA providing funding for instrument conversion, deployment, data analysis

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Purpose of the AQLNWG

1. Provide high-resolution time-height measurements of ozone and aerosols at a few sites from near surface to upper troposphere for scientific investigations of air-quality processes and GEO-CAPE mission definition.

2. Develop recommendations for lowering the cost and improving the robustness of such systems to better enable their possible use in future national networks to address the needs of NASA, NOAA, EPA and State/local AQ agencies.

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Charge to the AQLNWG1. Is a lidar network for air-quality measurements a high priority for advancing the state of the

science? How would a NASA demonstration activity fit into monitoring needs/plans for other agencies and the nation? Can it fulfill needs for satellite retrieval algorithm development and cal/val?

2. Instrument hardware: Is a commercial solution available or imminent? What specific technology development may be required, and what mechanism is appropriate (e.g., NASA Centers, SBIR)? How soon could candidate instruments be available? Do we know these things, or should an RFI be issued?

3. What are the desired performance characteristics for: concentration, extinction, altitude range, sensitivity, measurement frequency, etc.?

4. What are the desired network characteristics: How many instruments would be needed for adequate demonstration? Where should they be located? Should portability be an emphasis? Consider value added by co-location within other networks (GALION, AERONET, MPLNET, profilers, AQ monitoring, supersites).

5. Synergies with other activities (field campaigns, e.g., Discover-AQ; routine aircraft profiling (MOZAIC/ IAGOS)). Assessment/improvement of CMAQ modeling. Integrated network system design strategy. Roles of different agencies/organizations.

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Science Investigations that the AQLNWG will address

1. Provide high spatio-temporal observations of PBL and FT ozone and aerosol for use by the GEO-CAPE science team to study the character of the atmospheric structure that GEO-CAPE will observe and assess the fidelity with which a geo instrument can measure that structure.

2. Discover new structures and processes at the PBL/FT boundary, especially in the diurnal variation of that interface.

3. Foster use of these high-resolution ozone and aerosol observations to improve the processes in air-quality forecast and diagnostic models.

4. Exploit synergy with DISCOVER AQ, thermodynamic profilers, MOZAIC/IAGOS, regulatory surface monitors, and other networks.

5. Improve our understanding of the relationship between ozone and aerosols aloft and surface ozone and PM values. [Fairlie et al., 2009] [Thompson, et al., 2008] [Morris, et al., 2010].

6. Advance our understanding of processes controlling regional background atmospheric composition (including STE and long range transport) and their effect on surface air quality to prepare for the GEO-CAPE era.

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Instruments and Locations

Technology considerations and Brassboard instruments: 4 lidar technology approaches (YAG pumped Raman cells, YAG pumped Ce:LiCAF tunable laser, YAG pumped dye laser, OPO.

Location. Begin with current expertise at their locations. Also develop mobile lidars. Undertake minimal instrument configuration changes to allow focus on making

ozone measurements from near surface to middle or upper troposphere at several different locations across the USA that span the variability space.

TMF: 2-color Raman-cell system downwind of Los Angeles. Reduce lower altitude to ~few hundred meters AGL.

ESRL: Boulder, CO, Convert a/c TOPAZ lidar to ground-based scanning mobile instrument.

UAH: Huntsville, AL, Implement 3-color Raman-cell lidar and reduce lower altitude to ~200m AGL.

LaRC: Bring SESI Ce:LiCAF lidar to operation in a mobile configuration. GSFC: Construct a 2-color Raman-cell lidar instead of OPO.

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III. Scientific investigations addressed by the lidar network

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May 01 May 02 May 03 May 04 May 05 May 06 May 07 May 08

May 3, 2010

Daytime PBL top collapsed

Evolution of the Boundary Layer Ozone Maximum-lidar measurements and RAQMS model simulation (modeled by B. Pierce/U. of Wisconsin-Madison)

May 4 May 5

May 6 (high PBL O3)

Missed

May 7

EPA surface

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Co-located ceilometer backscatter

Low-level jet

Co-located wind profiler

Positive correlation of ozone and aerosol due to transport

Oct. 4, 2008

Kuang et al. Atmospheric Environment 2011

Aerosol

Lidar

O3 Transport: Nocturnal O3 enhancement associated with low-level jet

Oct. 2, 08

Oct. 3, 08

Oct. 1, 08

Oct. 5, 08 Oct. 6, 08

Oct. 4, 08

Surface O3 and convective boundary layer height

Higher increasing rate of the surface O3 due to the low-level transport on the previous day

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GOME total O3 Nov. 5

Stratospheric O3, zero RH

Sonde

Stratosphere-to-troposphere transport and its CMAQ Model simulation, Nov. 5, 2010

Huntsville

Lidar O3

Ozonesonde showing the high O3 and dry layer

Modeled by Arastoo Pour-Biazar/UAH

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High-resolution PBL lidar observation suggests both UV and Vis radiances required to capture significant PBL signal for satellite

Huntsville lidar observation on Aug. 4, 2010

Lidar obs. convolved with OMI UV averaging kernel---- unable to capture the highly variable ozone structure in PBL

Lidar obs. Convolved with OMI UV-Vis averaging kernel----Captures the PBL ozone structure. X. Liu et al.

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Stratospheric contribution to high surface ozone in Colorado during springtime A.O. Langford, K.C. Aikin1, C.S. Eubank1, E.J Williams1

Chemical Sciences Division ESRL, NOAA, Boulder, Colorado USA 1also at Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA.

Langford NOAA/ESRL/CSD

Stratospheric

Tropospheric

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E.J. Williams

Surface O3 and CO anticorrelatedLangford NOAA/ESRL/CSD

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CDPHE and NPS monitors

Surface O3 increased from 55 to 100 ppbv in RMNP!

Langford NOAA/ESRL/CSD

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JPL/TMF ozone & water vapor lidars

Ozone (left) and water vapor (Right) with 10 minute resolution showing the progression of a stratospheric intrusion and the anti-correlation between ozone and water.

O3 H2O

S. McDermid

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III. Sites and hardware configurations

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UAH NASA/LaRCJPL/TMF

NOAA/ESRL

Initial sites of the ground-based lidar network to provide O3 and aerosol data for air-quality study and GEO-

CAPE mission

22

NASA/GSFCAncillary site info:TMF: sondes,ESRL: weekly sondesUAH: weekly sondes, miniMPL, physical profilers (T, U, ceilometer).LaRC: need CAPABLE inputGSFC: need input

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UAHuntsville planned configuration 3 receiver channels covering 0.1-12km

1. 3- λ ( 283-289-299) system to minimize aerosol interference2. Adding a 1-inch mini receiver channel to reduce the lowest measurement

altitude to ~100m from the current 500m3. Expected operation by summer 2012

Schematic diagram of the future transmitters and receivers.

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TOPAZ: NOAA’s airborne Ozone/Aerosol Lidar(TOPAZ = Tunable Optical Profiler for Aerosols and oZone)

• Compact, light-weight, all solid state lidar

• 3 tunable UV wavelengths

• Designed for nadir-looking deployment on NOAA Twin Otter

• Measures ozone and aerosol backscatter profiles

• Altitude coverage: from near the surface up to 5 km MSL

• Resolution (O3): 90 m vertical, 600 m horizontal

• Precision (O3) : 2-15 ppb

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TOPAZ modifications for ground-based, scanning operation

1. Invert telescope to zenith-looking

2. Install in truck with roof top scanner

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Scan strategy & expected performance of ground-based TOPAZ

Anticipated instrument performance

Time resolution: 1 min per angle; 5 min per scan sequence Range/altitude resolution: 90 m; 3 – 90 m Range/altitude coverage: 400 m – 4 km; 17 m – 4 km AGL Precision: 1 – 10 ppb (SNR and range dependent)

90º

10º

2º

17 m AGL

~4 km AGL

3-angle scan sequence designed to provide composite O3 profiles from 17 m to approx. 4 km AGL. Horizontal stares will be performed occasionally.

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Deployments of ground-based TOPAZ in FY 2012

1. Uintah Basin Ozone Study (UBOS)

The UBOS study is designed to examine in detail the role of local atmospheric chemistry and meteorology in producing high wintertime O3 concentrations in the Uintah Basin in NE Utah.

TOPAZ will provide horizontal and vertical profiles of ozone as well as estimates of boundary layer height.

Time frame: February/March 2012

2. Local measurements (Boulder, Fritz Peak)

TOPAZ will measure vertical profiles of ozone at regular intervals at NOAA/ESRL in Boulder or at the Fritz Peak Observatory to a) provide a vertical context for the routine surface O3 observations in the greater Denver area and b) extend the record of mid-tropospheric ozone profile measurements by Langford et al. from the 1990s.

Time frame: April – September 2012

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Comparison of the target configurations of the O3 lidars at different sites

Site Characteristics Strength Weakness Measurable range (agl)

Anticipated operation year

JPL/TMF Quadruple YAG pumped Raman laser, 3-λ,3-receiver

355nm channel measuring aerosol

Fixed location, Limited daytime measurements

0.1-15 km 2012

NOAA/ESRL Nd:YLF pumped Ce:LiCAF tunable 2-λ,1-receiver, scanning, mobile

Tunable wavelength, Scanning, mobile

Only 2-λ, potential aerosol interference, limited alt measurement range

0.4-4 km 2012

UAHuntsville Quadruple YAG pumped Raman laser, 3-λ,3-receiver

Low PBL measurement, UV dual-DIAL removing aerosol effect

Fixed location, no scanning initially.

0.1-12 km 2012

NASA/GSFC High freq. OPO, 2-λ,1-receiver. Expect to implement YAG-pumped Raman lidar.

OPO is a tunable lidar, can be mobile. Raman lidar more powerful.

OPO limited power.Raman-cell lidar fixed location.

0.5-12 km 2012

NASA/LaRC Nd:YLF pumped Ce:LiCAF tunable 2-λ,1-receiver, scanning, mobile

Tunable wavelength, mobile

Only 2-λ, potential aerosol interference, limited alt measurement range

0.4-4km 2012

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Conclusions

• Ozone/aerosol lidar research initiative will address compelling science questions of regional/local processes controlling air quality

– Laminar structures associated with long range pollutant transport and stratospheric influence– Residual O3 aloft and diurnal PBL pumping

• These measurements will be used to– Measure the impact of ozone aloft on surface ozone over a diverse range of air-quality

environments in the US– Evaluate air quality models to improve their simulation and forecasting capabilities– Provide high time-resolved observations to begin preparing for GEO-CAPE satellite mission

observations expected early in the next decade– Inform future discussion about whether such measurements are needed routinely

• Leveraging significant current instrumentation and expertise provides a cost effective way to obtain these research observations

• Interagency interest and participation, and engagement of non-Federal partners to address high-priority research gaps, enhances the probability of effective outcome

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Backup

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LaRC ozone lidar

Telescope

Lidar ControlDAQ System

Receiver Box

Laser Transmitter

1. Ground-based, but can be modified to a mobile system2. Tunable two wavelengths within 282-313 nm for O3 measurement3. 527nm for aerosol measurement

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GSFC tropospheric ozone lidar

Schematic of the Non-Linear Optics bench within the laser. The Nd-YAG laser is mounted upside down on the underside of the NLO bench. The 1064 nm pump beam enters the NLO bench at the lower right.

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TOPAZ applications

TexAQS 2006: Quantifying horizontal transport of O3 downwind from Houston and Dallas

Cross sections of ozone downwind of Houston measured with TOPAZ on 08/14/2006. Ozone fluxes are computed for each transect by integrating above-background ozone across the plume and multiplying with horizontal wind speed measured with radar wind profilers.

Ozone fluxes as a function of plume age downwind from Houston and Dallas (includes data from TexAQS 2000).

Senff, C. J. et al., 2010: Airborne lidar measurements of ozone flux downwind of Houston and Dallas, J. Geophys. Res., 115, D20307, doi:10.1029/2009JD013689.

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TOPAZ applications

Pre-CalNex 2009: Orographic lifting & long-range transport of O3 originating in the Los Angeles Basin

SMOG model predictions (top) comparedwith TOPAZ lidar observations (bottom).

48-h (solid) and 60-h (dotted) forward trajectories suggesting long-range transport aloft of O3 from Los Angeles to Utah and Colorado.

Langford, A. O., et al., 2010: Long-range transport of ozone from the Los Angeles Basin: A case study, Geophys. Res. Lett., doi:10.1029/2010GL042507.