Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements

doi:10.5194/acp-2020-294

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-294
	Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements
	Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Alexander Haefele, and Francisco Navas-Guzmán
	2020-05-06
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	Remote sensing measurements by light detection and ranging (lidar) instruments are fundamental for the monitoring of altitude-resolved aerosol optical properties. Here, we validate vertical profiles of aerosol backscatter coefficient (β_aer) measured by two independent lidar systems using co-located balloon-borne measurements performed by Compact Optical Backscatter Aerosol Detector (COBALD) sondes. COBALD provides high-precision in-situ measurements of β_aer at two wavelengths (455 and 940 nm). The two analyzed lidar systems are the research Raman Lidar for Meteorological Observations (RALMO) and the commercial CHM15K ceilometer (Lufft, Germany). We consider in total 17 RALMO and 31 CHM15K profiles, co-located with simultaneous COBALD soundings performed throughout the years 2014–2019 at the MeteoSwiss observatory of Payerne (Switzerland). The RALMO (355 nm) and CHM15K (1064 nm) measurements are converted to respectively 455 nm and 940 nm using the Angstrom exponent profiles retrieved from COBALD data. To account for the different receiver field of view (FOV) angles between the two lidars (0.01–0.02°) and COBALD (6°), we derive a custom-made correction using Mie-theory scattering simulations. Our analysis shows that both RALMO and CHM15K achieve a good agreement with COBALD measurements in the boundary layer and free troposphere, up to 6 km altitude, and including fine structures in the aerosol’s vertical distribution. For altitudes below 2 km, the mean ± standard deviation difference in β_aer is + 6 % ± 40 % (+ 0.005 ± 0.319 Mm⁻¹ sr⁻¹) for RALMO – COBALD at 455 nm, and + 13 % ± 51 % (+ 0.038 ± 0.207 Mm⁻¹ sr⁻¹) for CHM15K – COBALD at 940 nm. The large standard deviations can be at least partly attributed to atmospheric variability effects, associated with the balloon’s horizontal drift with altitude (away from the lidar beam) and the different integration times of the two techniques. Combined with the high spatial and temporal variability of atmospheric aerosols, these effects often lead to a slight altitude displacement between aerosol backscatter features that are seen by both techniques. For altitudes between 2–6 km, the absolute standard deviations of both RALMO and CHM15K decrease (below 0.13 and 0.16 Mm⁻¹sr⁻¹, respectively), while their corresponding relative deviations increase (often exceeding 100 % COBALD of the signal). This is due to the low aerosol content (i.e. low absolute backscattered signal) in the free troposphere, and the vertically decreasing signal-to-noise ratio of the lidar measurements (especially CHM15K). Overall, we conclude that the β_aer profiles measured by the RALMO and CHM15K lidar systems are in good agreement with in-situ measurements by COBALD sondes up to 6 km altitude.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/248807
专题	地球科学
推荐引用方式 GB/T 7714	Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Alexander Haefele, and Francisco Navas-Guzmán. Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements[J]. Atmospheric Chemistry and Physics,2020.
APA	Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Alexander Haefele, and Francisco Navas-Guzmán.(2020).Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements.Atmospheric Chemistry and Physics.
MLA	Simone Brunamonti, Giovanni Martucci, Gonzague Romanens, Yann Poltera, Frank G. Wienhold, Alexander Haefele, and Francisco Navas-Guzmán."Validation of aerosol backscatter profiles from Raman lidar and ceilometer using balloon-borne measurements".Atmospheric Chemistry and Physics (2020).