Pure rotational-Raman channels of the Esrange lidar for temperature and particle extinction measurements in the troposphere and lower stratosphere

Abstract

Abstract. The Department of Meteorology at StockholmUniversity operates the Esrange Rayleigh/Raman lidar at Esrange (68 • N, 21 • E) near the Swedish city of Kiruna. This paper describes the design and first measurements of the new pure rotational-Raman channel of the Esrange lidar. The Esrange lidar uses a pulsed Nd:YAG solid-state laser operating at 532 nm as light source with a repetition rate of 20 Hz and a pulse energy of 350 mJ. The minimum vertical resolution is 150 m and the integration time for one profile is 5000 shots. The newly implemented channel allows for measurements of atmospheric temperature at altitudes below 35 km and is currently optimized for temperature measurements between 180 and 200 K. This corresponds to conditions in the lower Arctic stratosphere during winter. In addition to the temperature measurements, the aerosol extinction coefficient and the aerosol backscatter coefficient at 532 nm can be measured independently. Our filter-based design minimizes the systematic error in the obtained temperature profile to less than 0.51 K. By combining rotational-Raman measurements (5-35 km height) and the integration technique (30-80 km height), the Esrange lidar is now capable of measuring atmospheric temperature profiles from the upper troposphere up to the mesosphere. With the improved setup, the system can be used to validate current lidar-based polar stratospheric cloud classification schemes. The new capability of the instrument measuring temperature and aerosol extinction furthermore enables studies of the thermal structure and variability of the upper troposphere/lower stratosphere. Although several lidars are operated at polar latitudes, there are few instruments that are capable of measuring temperature profiles in the troposphere, stratosphere, and mesosphere, as well as aerosols extinction in the troposphere and lower stratosphere with daylight capability.

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

“…The Esrange lidar uses a pulsed frequency-doubled Nd:YAG (neodymium-doped yttrium aluminium garnet) solid-state laser operating at 532 nm wavelength as light source. The pulse energy of the laser was 350 mJ from 1997 to 2012 and since 2012 it has been 900 mJ (Achtert et al, 2013). The effective telescope diameter is 866 mm .…”

“…The implementation of rotationalRaman channels in November 2010 extended this range down to 4 km (Achtert et al, 2013). The integration technique can only be applied if the hydrostatic equilibrium equation and the ideal gas law are valid.…”

“…General details about the instruments are provided in and Achtert et al (2013). Measurements with the Esrange lidar are conducted on a campaign basis.…”

Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)<sup>2</sup> Observational Prototype Experiment

“…Rotational Raman lidars at 532 nm show lower performance during daytime but reach a larger range at night than an UV system due to the higher laser power available at 532 nm compared to 355 nm, higher efficiency in signal separation, and lower atmospheric extinction. Some of the systems at 532 nm are also based on interference filters (Behrendt and Reichardt, 2000;Behrendt et al, 2002Behrendt et al, , 2004Achtert et al, 2013), and some employ double-grating polychromators (Balin et al, 2004;Arshinov et al, 2005).…”

Pure Rotational Raman Lidar for Temperature Measurements from 5-40 Km Over Wuhan, China

“…With a relatively stronger cross section than vibrational Raman, rotational Raman (RR) lidar is a candidate for high precision temperature measurements from the ground to the upper stratosphere, even in the presence of aerosols and optically-thick cloud layers [4] . With progress in technologies of spectral extraction and weak signal detection, the temperature detection altitude for RR lidar can be extended upward to the stratosphere [5,6] . However, it is still a challenge for the RR technique to provide temperature measurements up to above 30 km with high precision.…”