Advancement and demonstration of a perturbative retrieval technique for temperature profiling in the lower troposphere using differential absorption light detection and ranging

In response to a community-identified need for ground-based thermodynamic (TD) profiling of the troposphere, we present the further development and validation of a differential absorption LiDAR (DIAL) technique to retrieve temperature. This paper showcases the accuracy of temperature retrievals using a perturbative technique, combining a DIAL measurement of a temperature-sensitive oxygen absorption profile with a high spectral resolution LiDAR measurement of the backscatter ratio profile near 770 nm. This study introduces three key advancements. First, the spectroscopic model used to represent the absorption of light by is enhanced via a more complete physical representation, improving measurement accuracy. Second, the error estimation and masking are developed using the bootstrapping technique. Third, we present a comparison of temperature profiles from our laboratory-based instrument with collocated radiosondes, evaluating the accuracy of our updated measurements. It is essential to clarify that the instrument described in this paper does not operate as a stand-alone TD profiler, as it is not capable of measuring water vapor (WV). Instead, we focus on demonstrating the perturbative retrieval technique with temperature profiles inferred using ancillary radiosonde WV profiles. Results from a full TD profiling instrument will be presented in a future publication. The laboratory-based LiDAR instrument was operated over a 6-month period between April 21, 2022, and September 22, 2022. During this time, we launched 40 radiosondes, providing reference data to validate the accuracy of the DIAL-based temperature profiles. The results indicate that DIAL-based temperature retrievals are within between 0.4 and 3 km (3.5 km) during daytime (nighttime) operation, using a 300-m range resolution and a 60-min time resolution.