Observations of The Lower-Tropospheric Temperature Profiles Using Three Wavelength CO2-DIAL

Yasukuni Shibata,Makoto Abo,Nagasawa Chikao

doi:10.1051/epjconf/202023703021

Yasukuni Shibata, Makoto Abo + Show 1 more

Open Access

https://doi.org/10.1051/epjconf/202023703021

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Journal: EPJ web of conferences	Publication Date: Jan 1, 2020
License type: CC BY 4.0

Affiliation: Tokyo Metropolitan University

Abstract

The eye-safe lower-tropospheric temperature profiler with three wavelength differential absorption lidar (DIAL) technique which can perform the continuous temperature profile observation through daytime and nighttime is conducted. The DIAL consists of a Nd:YAG laser pumped an OPG tuned around 1573 nm of an CO2 absorption line with 2 mJ/pulse at 400 Hz repetition rate and a receiving telescope of 25cm diameter. In this paper, we show the result of continuous temperature profile observations over 25 hours from 0.39 to 2.5 km altitude in the lower-troposphere. We can see temporally the generation and disappearance of the temperature inversion layers in the planetary boundary layer.

Highlights

Continuous observations of the temperature profile of lower-troposphere are important for studies in the atmospheric science
In lower-troposphere observation, achievement of the high rejection rate for the Mie scattering signal is difficult for the rotational Raman lidar (RRL) and the high-spectral resolution lidar (HSRL)
We added a third wavelength for temperature measurement to the conventional two-wavelength differential absorption lidar (DIAL)

Summary

INTRODUCTION

Continuous observations of the temperature profile of lower-troposphere are important for studies in the atmospheric science. The lidar is the most effective instruments for temperature profiling with high temporal and spatial resolutions. Different lidar techniques for measuring the atmospheric temperature profile have been developed, namely the rotational Raman lidar (RRL), the high-spectral resolution lidar (HSRL) technique and the DIAL1. In lower-troposphere observation, achievement of the high rejection rate for the Mie scattering signal is difficult for the RRL and the HSRL. As the solar background noise is higher in UV and visible wavelength, high power laser is required. The 1.6 μm CO2 absorption band has the reasonable absorption intensity for DIAL observations in the troposphere[2,3,4]. In addition to λon (1572.992 nm) and λoff (1573.137 nm), the third wavelength λT (1573.040 nm) for

TEMPERATURE OBSERVATIONS

DISCUSSION AND CONCLUTION