Reply on RC1

Igor Veselovskii

doi:10.5194/acp-2021-1017-ac1

Abstract

A remote sensing method, based on fluorescence lidar measurements, that allows to detect and to quantify the smoke content in upper troposphere and lower stratosphere (UTLS) is presented. The unique point of this approach is that, smoke and cirrus properties are observed in the same air volume simultaneously. In the article, we provide results of fluorescence and multiwavelength Mie-Raman lidar measurements performed at ATOLL observatory from Laboratoire d’Optique Atmosphérique, University of Lille, during strong smoke episodes in the summer and autumn seasons of 2020. The aerosol fluorescence was induced by 355 nm laser radiation and the fluorescence backscattering was measured in a single spectral channel, centered at 466 nm of 44 nm width. To estimate smoke properties, such as number, surface area and volume concentration, the conversion factors, which link the fluorescence backscattering and the smoke microphysical properties, are derived from the synergy of multiwavelength Mie-Raman and fluorescence lidar observations. Based on two case studies, we demonstrate that the fluorescence lidar technique provides possibility to estimate the smoke surface area concentration within freshly formed cirrus layers. This value was used in smoke INP parameterization scheme to predict ice crystal number concentrations in cirrus generation cells.

Highlights

Heterogeneous ice nucleation initiated by insoluble inorganic materials such as mineral dust has been studied since a long time (e.g., DeMott et al 2010, 2015; Hoose and Möhler, 2012; Murray et al, 2012; Boose et al, 2016; Schrod et al, 2017; Ansmann et al 2019b), while the potential of omnipresent organic particles, especially of frequently occurring aged, long-range-transported wildfire smoke particles, to act as ice nucleating particles (INP) is less well explored and not well understood (Knopf et al, 2018)
It is widely assumed that the ability of smoke particles to serve as INP mainly depends on the organic material (OM) in the shell of the coated smoke particles (Knopf et al, 2018), but may depend on mineral components in the smoke particles (Jahl et al, 2021)
The results demonstrate that the fluorescence lidar is capable to monitor the smoke in the upper tropospheric and lower stratospheric (UTLS) height range and inside the cirrus clouds formed at or below the tropopause

Summary

Introduction

Heterogeneous ice nucleation initiated by insoluble inorganic materials such as mineral dust has been studied since a long time (e.g., DeMott et al 2010, 2015; Hoose and Möhler, 2012; Murray et al, 2012; Boose et al, 2016; Schrod et al, 2017; Ansmann et al 2019b), while the potential of omnipresent organic particles, especially of frequently occurring aged, long-range-transported wildfire smoke particles, to act as INP is less well explored and not well understood (Knopf et al, 2018). Disregarding the progress made in this atmospheric research field during the last years, the link between ice nucleation efficiency and the smoke particle chemical and morphological properties is still largely unresolved (China et al, 2017; Knopf et al, 2018)

Methods

Results

Conclusion