A ground-based differential absorption lidar system has been implemented to make long-term, precise measurements of stratospheric ozone concentration profiles from ~20 to 50 km altitude. This lidar is located at an elevation of 2300 m in the San Gabriel Mountains, Southern California, and has been in operation since Jan.1988. A high power (100-W) excimer laser system and a 90-cm diam telescope are used to achieve the desired performance levels. This paper describes the implementation of the system and its operation including the procedures for data analysis. Examples of ozone profiles measured, and intercomparisons with measurements made by other instruments, are presented which show that the lidar, in its present configuration, is capable of producing high quality ozone measurements from 20 km up to at least 45 km.

Ground-based laser DIAL system for long-term measurements of stratospheric ozone. [differential absorption lidar system

The purpose of this work is to measure the ozone vertical distribution (OVD) in the upper troposphere–stratosphere by differential absorption lidar (DIAL) at 299/341 nm and 308/353 nm and to compare and analyze the results against satellite data. А lidar complex for measuring the OVD in the altitude range ≈(5–45) km has been created. Here we analyze the results of ozone lidar measurements at wavelengths of 299/341 nm and 308/353 nm in 2018 at Siberian Lidar Station (SLS) and compare them with satellite (MLS/Aura and IASI/MetOp) measurements of OVD. The retrieved lidar OVD profiles in the upper troposphere–stratosphere in comparison with MLS/Aura and IASI/MetOp profiles, as well as the stitched OVD profile in comparison with the mid-latitude Krueger model, confirm the prospects of using the pairs of ozone sounding wavelengths 299/341 and 308/353 nm.

https://www.mdpi.com/2073-4433/11/2/196/pdf

Measurements of Ozone Vertical Profiles in the Upper Troposphere–Stratosphere over Western Siberia by DIAL, MLS, and IASI

Laser ranging methods employing light detection and ranging (LiDAR) technology are widely used for studying the atmosphere and monitoring its state. The purpose of this work is to measure the ozone...

Comparison of ozone vertical profiles in the upper troposphere–stratosphere measured over Tomsk, Russia (56.5° N, 85.0° E) with DIAL, MLS, and IASI

Rayleigh and sodium lidar system incorporating time-division and wavelength-division multiplexing

The purpose of the work is to study the influence of temperature correction on ozone vertical distribution (OVD) in the upper troposphere–stratosphere in the altitude range~(5–45) km, using differential absorption lidar (DIAL), operating at the sensing wavelengths 299/341 nm and 308/353 nm. We analyze the results of lidar measurements, obtained using meteorological data from MLS/Aura and IASI/MetOp satellites and temperature model, at the wavelengths of 299/341 nm and 308/353 nm in 2018 at Siberian Lidar Station (SLS) of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. To estimate how the temperature correction of absorption cross-sections influences the OVD retrieval from lidar measurements, we calculated the deviations of the difference between two profiles, retrieved using satellite- and model-based temperatures. Two temperature seasons were singled out to analyze how real temperature influences the retrieved OVD profiles. In the stratosphere, when satellite-derived temperature and model are used for retrieval, the deviations may reach absolute values of ozone concentration in the range from −0.97 × 1012 molecules × cm−3 at 19.7 km to 1.05 × 1012 molecules × cm−3 at 25.3 km during winter–spring season, and from −0.17 × 1012 molecules × cm−3 at height of 17.4 km to 0.27 × 1012 molecules × cm−3 at 40 km in summer–fall period. In the troposphere, when satellite-derived temperature is used in the retrieval, the deviations may reach absolute values of ozone concentration in the range from −1.95 × 1012 molecules × cm−3 at 18.6 km to 1.23 × 1012 molecules × cm−3 at 18.2 km during winter–spring season, and from −0.15 × 1012 molecules × cm−3 at height of 11.4 km to 0.3 × 1012 molecules × cm−3 at 8 km during summer–fall season.

https://www.mdpi.com/2073-4433/11/11/1139/pdf

Temperature Correction of the Vertical Ozone Distribution Retrieval at the Siberian Lidar Station Using the MetOp and Aura Data

We developed a mobile ozone differential absorption lidar system to simultaneously measure the vertical profiles of tropospheric and stratospheric ozone from an altitude of ~5 to 50 km. The system emits four laser beams at wavelength of 289 nm, 299 nm, 308 nm and 355 nm and receives their corresponding Mie/Rayleigh backscattering return signals, and two N2 Raman return signals at 332 nm and 387 nm shifted from 308 nm and 355 nm, respectively. An assembled telescope array with four 1.25-m telescopes (effective diameter > 2 m) collects the Rayleigh and Raman backscattering signals at 308/332 and 355/387 nm. This system is currently deployed at the Yangbajing Observatory in Tibet (~4300 m elevation) and has begun observations in regular campaign mode since October 2017. The lidar results agree very well with those observed by the Aura/MLS satellite. This novel ozone lidar system operates at the highest elevation of any such system in the world. The higher elevation and larger receiver aperture of this system yield a higher signal-to-noise ratio and lower statistical uncertainty.

A mobile differential absorption lidar for simultaneous observations of tropospheric and stratospheric ozone over Tibet.

The sodium fluorescence lidar utilizes a 589 nm narrowband pulse laser system to measure mesopause region atomic sodium density, atmospheric temperature, and wind. However, this system is complicated and unstable. The continuous-wave (CW) sodium laser system can achieve ultra-narrow bandwidth, all-solid-state, and small compact size, as such it is extremely valuable for mobile, aircraft, and space-borne applications. In this study, we developed the first pseudo-random modulated CW (PMCW) sodium lidar by using an electro-optic modulated narrowband 589 nm CW laser with an output power of ∼1.2W. A pseudorandom M-sequence-code with a length of 127 is used to achieve altitude information by modulating laser and then decoding photon signals. Also, a biaxial structure with 9 m separation between the optical axes of the transmitter and receiver is designed to suppress the strong near-ground signals, which are crucial for improving the signal-to-noise ratio (SNR) of the PMCW lidar system. Nighttime measurements on December 2-4, 2019 show that the SNR at sodium layer peak is more than 10, corresponding to a statistical uncertainty of less than 10% in sodium density with temporal and spatial resolutions of 5 min and 1.05 km respectively. The comparison of vertical profiles of sodium density simultaneously observed by PMCW lidar and collocated pulse lidar shows good agreement.

Baogang Tian

Papers

A mobile differential absorption lidar for simultaneous observations of tropospheric and stratospheric ozone over Tibet.

Pseudo-random modulation continuous-wave lidar for the measurements of mesopause region sodium density.