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

Yajuan Li,Faquan Li,Xuewu Cheng,Zhenwei Chen,Linmei Liu,Shalei Song,Shunsheng Gong,Yong Yang,M Patrick Mccormick,B Gross,F Moshary,M Arend

doi:10.1051/epjconf/201611925010

Abstract

In this paper a pure rotational Raman lidar (PRR) was established for the atmospheric temperature measurements from 5 km to 40 km over Wuhan, China (30.5°N, 114.5°E). To extract the expected PRR signals and simultaneously suppress the elastically backscattered light, a high-spectral resolution polychromator for light splitting and filtering was designed. Observational results revealed that the temperature difference measured by PRR lidar and the local radiosonde below 30 km was less than 3.0 K. The good agreement validated the reliability of the PRR lidar. With the 1-h integration and 150-m spatial resolution, the statistical temperature error for PRR lidar increases from 0.4 K at 10 km up to 4 K at altitudes of about 30 km. In addition, the whole night temperature profiles were obtained for study of the long-term observation of atmospheric fluctuations.

Highlights

The temperature structure of the atmosphere plays a key role in understanding the dynamical, radiative and coupling processes of different atmospheric layers [1]
This paper described the system design and observational results of a pure rotational Raman lidar (PRR) lidar for the temperature measurements from 5-40 km over Wuhan
With the high–spectral resolution polychromator for light splitting and filtering, rotational Raman (RR) scattering returns were detected by weak signal detection technology

Summary

Introduction

The temperature structure of the atmosphere plays a key role in understanding the dynamical, radiative and coupling processes of different atmospheric layers [1]. 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]. It is still a challenge for the RR technique to provide temperature measurements up to above 30 km with high precision. A large power-aperture product and sufficient suppression of the stronger elastic backscattering (about 6 - 8 orders of magnitude) are important steps to obtain signal-to-noise ratios (SNR) and precision that are required

Methods

Results

Conclusion