Tropospheric Ozone Lidar Network (TOLNet)Long-term Tropospheric Ozone Profiling for Satellites, Modeling, and
Chemistry Studies
NDACC Lidar Working Group Meeting, NASA/JPL, Table Mountain, CA,
Nov. 7, 2013
Mike Newchurch1, Raul Alvarez2, Jay Al-Saadi35, John Burris4, Wesley Cantrell1, Gao Chen5,
Russell DeYoung5, Mike Hardesty2, Ray Hoff6, Guanyu Huang, Jack Kaye3, Kevin Knupp1,
Alex Pszenny3, Shi Kuang1, Andy Langford2, Thierry Leblanc7, Stuart McDermid7, Tom McGee4,
Brad Pierce8, Christoph Senff2, John Sullivan4, Jim Szykman9, Gail Tonnesen9, and Lihua Wang1
TOLNet Motivation
Motived by the growing demand for high-temporal-resolution
ozone measurements at multiple stations with a reasonable cost for
air-quality studies, model input or evaluation, and satellite validation.
GEO-CAPE/TEMPO 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 augment the spaceborne measurements with a ground-based measurement system.
Ozonesondes are used extensively 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.
TOLNet Objectives
(1) Provide high-resolution time-height measurements of ozone and
aerosols at a few sites from near surface to upper troposphere for airquality/photochemical models and satellite retrieval validation;
(2) Support field campaigns and existing networks (e.g., DISCOVER-AQ,
SOAS, SENEX, SEAC4RS) to advance understanding of processes controlling
regional air quality and chemistry;
(3) 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.
NOAA Mobile Ozone Lidar at Discover-AQ Houston
The NOAA/ESRL mobile ozone lidar (TOPAZ) was
deployed in Houston, TX from 29 August to 27
September 2013 in support of the NASA Discover-AQ
campaign. TOPAZ was situated at the La Porte Airport
next to the TCEQ met tower and wind profiler and a
suite of O3 and NOx sensors operated by EPA.
TCEQ met
Time-height cross section of preliminary TOPAZ O3
observations on 25 September 2013.
EPA trailer
Instrumentation at the La Porte Airport site, shown during one
of the many missed approaches by the NASA-P3B aircraft.
The primary objective of the TOPAZ deployment was
to characterize the horizontal and vertical distribution
of O3 in the boundary layer in support of the DiscoverAQ aircraft observations. TOPAZ measurements were
also aimed at characterizing the O3 distribution during
the morning and evening transition periods and to
investigate the influence of the land sea breeze
On 25 September, light winds and recirculation of
pollutants by the sea breeze led to very high afternoon O3
concentrations. Titration of O3 in the shallow morning
boundary layer was followed by a quick increase in O3 due
to photochemical production. A rapid rise of the boundary
layer around midday caused a temporary drop in O3 levels
as cleaner air from aloft was mixed down. In the evening,
the sea breeze brought in lower-O3 air in the first 300 m
AGL, leaving a “dirty” residual layer aloft.
Preliminary TOPAZ data from the Discover-AQ Houston
campaign can be accessed under
Table Mountain Facility Ozone Lidar
JPL operates two DIAL systems at TMF
for measurement of ozone profiles. To
date, our emphasis has been free
troposphere and stratosphere
observations (NDACC) and signals from
low altitudes, below 4 km are purposely
blocked by a rotating shutter.
This figure shows an example of the
current capability of the ozone lidars and
an intercomparison with an ozone-sonde.
Transport often results in high
ozone plumes above the
boundary layer but that
sometimes mix to the surface.
Simultaneous ozone and water
vapor lidar observations at TMF
can clearly identify stratospheric
intrusions. This figure shows a
plume of high ozone correlated
with very low humidity,
characteristic of a stratospheric
To measure the ozone profile in the near
surface region currently not observed by our
lidar, we have designed and built two nearfield mini-receivers (one each for 289 and
299 nm). Two additional data acquisition
channels have also been procured (photo
right). Once operational we plan to validate
the low altitude measurements using tethered
ozone-sondes. We also plan to augment the
profile observations with surface ozone
measurements. The start of operations
depends on the availability of filters, currently
quoted at 12 weeks delivery. Anticipate
operational by 6/2012. Preliminary tests
indicate daytime operations will be possible.
27 January 2012
NASA/GSFC Mobile Lidar
Data acquisition system
Raman cells
Recent measurement example (O3 ppbv)
View from inside the 40’ trailer.
Moving from left to right: the rack for the data acquisition system; the optics module
package that houses the narrow band interference filters for the PMT’s, the chopper
attached to the telescope, which helps eliminate saturation of the PMT’s; the transmission
platform for two 1’’ detectors is mounted directly next to the 18’’ telescope for the nearground ozone measurements. The two 72’’ Raman cells mounted on the table produce
289 and 299-nm lasers using pressurized hydrogen and deuterium.
NASA/LaRC Mobile Lidar
2. Fiber-optic
3. Nd:YLF Laser
4.Ce:LiCAF Laser
5.Detector Array
6.Controls and Power
7.Transmitter Optics
Mobile Ozone DIAL system in laboratory
NASA Langley is developing an ozone lidar in a trailer that can be easily
deployed at locations throughout the U.S. The lidar will produce tunable on and
off ozone DIAL laser wavelengths between 280 and 300 nm at 500 Hz each.
There is also a 527 nm aerosol channel. The system has an in situ ozone
measurement capability which will allow ozone to be profiled from the ground
to the lower troposphere.
UAH Ground-based Ozone Lidar
The UAHuntsville O3 lidar system was developed jointly by UAHuntsville and NASA/GSFC
[Kuang et al., 2011a]. (Left) Receiver system showing the recently added 1’’ mini receiver to
measure ozone between 100 and 1000m altitude; (Right) Raman shifted YAG transmitter
replacing previous dye lasers. Located at a 200-m ASL slightly polluted city, this lidar makes
ozone retrieval from 0.1 to ~12 km during both daytime and nighttime with a typical
integration time from 2 to 10 min.
1’’ receiver (Ch-0)
16’’ receiver (Ch-5)
Laser outgoing
4’’ receiver (Ch-1 and
500m-1.5km, 1-5km
Laser transmitter
3. Data Access
The TOLNet ozone data are available to the scientific community through the NASA/LaRC
website with the TOLNet format defined by the working group. The format manual and
the IDL codes to write and read the data are provided on the website. Some stations (e.g.,
UAH, ESRL) also provide data in ICARTT format.

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