Atmospheric Remote Sensing: Instruments
Tunable Optical Profiler for Aerosol and oZone lidar (TOPAZ)
CSD designed and built the Tunable Optical Profiler for Aerosol and oZone lidar (TOPAZ). TOPAZ incorporates state-of-the-art technologies to make it compact and lightweight as well as having low power consumption. These features allow it to be deployed on smaller aircraft. Its wavelength flexibility permits optimization for differing atmospheric conditions including interference from other atmospheric components and allows dual-DIAL operation – introduction to Differential Absorption Lidar (DIAL) techniques.
This lidar was first deployed in the Texas Air Quality Study (TexAQS) 2006 field campaign to help examine pollution development and transport in the vicinity of Houston, Texas. During the experiment, TOPAZ proved to be a useful tool for the study of urban air quality by its ability to provide detailed coverage over a wide area for the mapping of ozone and aerosol plumes from an airborne platform. Additional information obtained from the lidar data included boundary height determination and ozone plume flux measurements.
TOPAZ is also part of the NASA Tropospheric Ozone Lidar Network (TOLNet) - ground-based profiling of tropospheric ozone. More recently TOPAZ has been used to measure the ozone distribution along the Front Range of Colorado, and other areas of the western United States. The lidar was installed in a box truck, and this mobile unit deployed to take ozone measurements aloft.
Basic Parameters Measured
- Ozone concentration profiles
- Aerosol backscatter
|California Baseline Ozone Transport Study (CABOTS) 2016||June-August 2016||Visalia, California (ground site)|
|DISCOVER-AQ 2014||July-August 2014||Erie, Colorado (ground site)|
|DISCOVER-AQ 2013||September 2013||Houston, Texas (ground site)|
|Las Vegas Ozone Study (LVOS) 2013||May-June 2013||Angel Peak, Nevada (ground site)|
|Uintah Basin Winter Ozone Study (UBWOS) 2013||January-February 2013||Horsepool, Utah (ground site)|
|Uintah Basin Winter Ozone Study (UBWOS) 2012||February 2012||Horsepool, Utah (ground site)|
|California Research at the Nexus of Air Quality and Climate Change (CalNex) 2010||May-July 2010||Southern California (Twin Otter, aircraft based)|
|Texas Air Quality Study (TexAQS) 2006||July-September 2006||Houston, Texas (Twin Otter, aircraft based)|
|Tuning range||285-310 nm (three wavelengths)|
|Pulse energy||0.2-0.8 mJ/pulse|
|Pulse rate||1 kHz with pulse-to-pulse tuning capability
(333 Hz for each individual wavelength)
|Laser||Diode-pumped Nd:YLF laser quadrupled in LBO (intracavity) and CLBO (external) to 262 nm to pump Ce:LiCAF in a tunable cavity|
|Minimum range||0.3 km|
|Maximum range||4 km|
|Eye-safe range||150 m|
|System weight||800 lbs (including chiller and control electronics)|
|Dimensions||30" x 56" x 45" laser/optics frame, 15" x 25" x 24" chiller
Electronics in standard 19" equipment racks ~49" (28U)
|System power||3 kW, 110VAC|
|Digitizer||FPGA-based digitizer (14 bits, 100MHz sample rate)|
|Output||Real-time ozone and aerosol profiles displayed in flight.
Data is recorded to a solid state disk drive.
|Vertical/horizontal resolution||90 m / 600 m (10 s at a flight speed of 60 m/s)|
|Accuracy||±3 - ±15 ppbv (depends on range and ozone concentration)|