UAH Ground-based Ozone Lidar -A New NDACC Lidar Station Member

NDACC Lidar Working Group Meeting, NASA/JPL, Table Mountain, CANov. 4, 2013

http://nsstc.uah.edu/atmchem

Shi Kuang1, Mike Newchurch1, John Burris2, Wesley Cantrell1 1UAHuntsville, 2NASA/GSFC

UAH Robert Cramer Research Hall

Outline

• 1. Introduction to the location• 2. Introduction to the UAH O3 lidar

instrument• 3. Other synergistic instruments at UAH• 4. Future plans

The Location

Simulated and obs (circles) organic carbon at surface in 2010.

Surrounded by large cities.

Leibensperger et al. ACP 2012

[Cooper et al., 2007]

Summertime upper tropospheric O3 maximum above Huntsville

Overview(34.7250N, 86.6450W)200m ASL~100 clear days and ~100 cloudy days per year

Current UAH Ozone Lidar Configuration

UAH O3 DIAL

The UAH O3 DIAL currently measures O3 with two λ (289-299), three telescopes, and four altitude channels. This system profiles O3 up to ~12 km with a temporal resolution 2-10 min and a vertical resolution of 150-750 m.We have plans to add a third λ for more accurate PBL O3 retrievals.

1

4

Licel TR

PMT

30Hz, 5-7 mJ/pulse

10cm

40cm Telescope

2

3

2.5cm

10%

90%

289/299

289/299

289/299Beamsplitter

Pin hole or iris

x

z

289/299 laser

Solar & ND filters

Pulse generator

PhotodiodeFunction generator

289/299

GateGateTrigger

Trigger

Laser Transmitter

Upgraded the transmitter from dye lasers to Raman-shifted lasers for a more stable output, quicker initialization, and easier operation. Data after May 2013 are mostly taken with the 289-299nm pair.

Previous: 532 YAG pumped dye lasers (285-291nm)

Current: 266 YAG pumped Raman-shifted (289-299nm)

266 Pump

Receiver and Detector

1’’ receiver (Ch-1)100m-1km

Laser outgoing mirror

16’’ receiver (Ch-4)3-12km

4’’ receiver (Ch-2 and Ch-3)500m-1.5km, 1-5km

3 telescopes and 4 photomultiplier (PMT) channels

Measurable alt range

Added a 1’’ channel in Feb. 2013.

Validation

Figure 11. Comparison of the low-altitude (solid) and high-altitude (dash) channel aerosol-corrected retrievals with the coincident ozonesonde (dot) measurements.

O3 (1012 molec cm-3)

Alt (

km)

[Kuang et al. 2013 Applied Optics][Kuang et al. 2011a IEEE-TGRS]

The retrieval accuracy ranges from better than 10% in the low and mid troposphere and better than 20% in the upper troposphere with 2-10 min temporal integration.

1. Against sondes in [Kuang et al. 2011a]2. Preliminary results in [Kuang et al. 2013]3. Confirmed by the extensive coincident

lidar/sonde obs. in 2013 summer SEAC4RS.

Synergistic Instruments at UAH

Ozonesonde, T, P, O3, RH, wind

Courtesy of Kevin Knupphttp://vortex.nsstc.uah.edu/mips/system/

SfcSodar

Ceilometer

915 profiler

MPR

915: SNR, vertical velocity, spectral width, horizontal wind, Doppler spectraCeilometer: backscatter, cloud base heightMPR: T, water vapor, cloud waterSodar: SNR, spectral width, horizontal windSurface; T, RH, P, wind, solar radiationSource: [Karan and Knupp, 2006]

Halo Doppler wind lidar: wind velocity, backscatter, scanning capability

Synergistic Instruments at UAH

Image from the manufacture

Surface O3 monitor, high temporal O3 mixing ratio

Wisconsin HSRL (Ed Eloranta et al.) deployed at Huntsville in 2013 summer: backscatter, color ratio, depolarization ratio.

Future Plans

• 1. Taking data on the NDACC schedule and achieving data using the NDACC protocol.

• 2. Improving the retrieval precision by adding a third wavelength (283.6nm) .

• 3. Adding 289nm narrow-band and 283-289nm band-pass filters.

• 4. Continuing scientific studies using the ozone lidar data.

Backup Slides

Table 1. Characteristics of the UAH ozone lidar. SpecificationTransmitter Pump lasers Nd:YAG, 30-Hz repetition rate, 25-30 mJ·pulse-1 at 266 nmRaman cell 2.5 cm of diameter and 185 cm of lengthRaman gases N2 and He for 283.6 nm, D2 and He/Ar for 289 nm, H2 and Ar for 299 nm,Emitted UV light 7-10 mJ·pulse-1 at 285 and 291 nm; 4-5 mJ·pulse-1 at 283.6 nm, ~7-ns pulse length and divergence<1 mrad for all

laser beams

Receiver Channel 1 Channel 2 Channel 3 Channel 4Diameter (cm) 2.5 10 10 40Focal length (m) 0.1 2.3 2.3 4.5Separation from the laser beams (cm) 10 20 20 50FOV (mrad) 10 4.3 4.3 1.5Full overlap height (m) 20 90 90 1200Light split percentage (%) 100 10 90 100Solar blind filter Center wavelength at 286.4 nm with a 11-nm FWHM; 35% Transmittance at 285 nm and 20% Transmittance at

291 nmNeutral density filter transmittance 10% 10% 32% NAPMT type Hamamatsu R9880U Hamamatsu R7400U Hamamatsu R7400U Electron Tube9831QAGated PMT delay (μs) 0 0 1 >10Measurable height range (km) 0.1-1 0.4-1.5 1-4 3-12

Signal Processing Channel 1 Channel 2 Channel 3 Channel 4Photoncounting 250-MHz maximum counting rate Analog 12-bit and 40-MHz analog-to-digital converterFundamental range resolution (m) 3.75 3.75 3.75 3.75Actual range resolution due to average (m)*

22.5 45 75 150

* This is equal to the range interval for reported ozone.

Planned Configuration of the UAH Ozone Lidar

Planned configuration for UAH O3 DIAL

The UAH O3 DIAL currently measures O3 with two λ (289-299), three telescopes, and four altitude channels. We have plan to add a third λ for more accurate PBL O3 retrievals. This system profiles O3 up to ~12 km with a temporal resolution 2-10 min and a vertical resolution of 150-750 m.