Raman lidar observations of a Saharan dust outbreak event: Characterization of the dust optical properties and determination of particle size and microphysical parameters

Girolamo, Paolo Di; Summa, Donato; Bhawar, Rohini; Iorio, Tatiana Di; Cacciani, Marco; Veselovskii, Igor; Dubovik, Оleg; Kolgotin, Alexei

doi:10.1016/j.atmosenv.2011.12.061

Cited by 65 publications

(54 citation statements)

References 55 publications

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“…The Raman lidar system BASIL (Di Girolamo et al, 2009;Di Girolamo et al, 2012) is an active instrument detecting the elastic and Raman backscattered radiation from atmospheric constituents. BASIL includes a Nd:YAG laser emitting pulses at its fundamental wavelength, and its second and third harmonics: 355, 532 and 1064 nm, respectively, at a repetition rate of 20 Hz.…”

Section: Basilmentioning

confidence: 99%

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

et al. 2016

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Abstract. Continuous monitoring of atmospheric humidity profiles is important for many applications, e.g., assessment of atmospheric stability and cloud formation. Nowadays there are a wide variety of ground-based sensors for atmospheric humidity profiling. Unfortunately there is no single instrument able to provide a measurement with complete vertical coverage, high vertical and temporal resolution and good performance under all weather conditions, simultaneously. For example, Raman lidar (RL) measurements can provide water vapor with a high vertical resolution, albeit with limited vertical coverage, due to sunlight contamination and the presence of clouds. Microwave radiometers (MWRs) receive water vapor information throughout the troposphere, though their vertical resolution is poor. In this work, we present an MWR and RL system synergy, which aims to overcome the specific sensor limitations. The retrieval algorithm combining these two instruments is an optimal estimation method (OEM), which allows for an uncertainty analysis of the retrieved profiles. The OEM combines measurements and a priori information, taking the uncertainty of both into account. The measurement vector consists of a set of MWR brightness temperatures and RL water vapor profiles. The method is applied to a 2-month field campaign around Jülich (Germany), focusing on clear sky periods. Different experiments are performed to analyze the improvements achieved via the synergy compared to the individual retrievals. When applying the combined retrieval, on average the theoretically determined absolute humidity uncertainty is reduced above the last usable lidar range by a factor of ∼ 2 with respect to the case where only RL measurements are used. The analysis in terms of degrees of freedom per signal reveal that most information is gained above the usable lidar range, especially important during daytime when the lidar vertical coverage is limited. The retrieved profiles are further evaluated using radiosounding and Global Position Satellite (GPS) water vapor measurements. In general, the benefit of the sensor combination is especially strong in regions where Raman lidar data are not available (i.e., blind regions, regions characterized by low signal-to-noise ratio), whereas if both instruments are available, RL dominates the retrieval. In the future, the method will be extended to cloudy conditions, when the impact of the MWR becomes stronger.

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Section: Basilmentioning

confidence: 99%

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

et al. 2016

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Section: Methodsmentioning

confidence: 99%

Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

Girolamo

Flamant

Cacciani

et al. 2017

AIP Conference Proceedings

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Abstract. Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) Special Observation Period 1 (SOP1). Low-level wind reversals associated with these transitions are found to have a strong impact on water vapour transport, leading to a large variability of the water vapour vertical and horizontal distribution. The high spatial and temporal resolution of the lidar data allow to monitor the time evolution of the three-dimensional water vapour field during these transitions from predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow, allowing to identify the quite sharp separation between these flows, which is also quite well captured by the mesoscale models.

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“…The major feature of BASIL is represented by its capability to perform high-resolution and accurate measurements of atmospheric temperature and water vapour, both in daytime and night-time, based on the application of the rotational and vibrational Raman lidar techniques in the UV. Besides temperature and water vapour, BASIL is also capable of providing measurements of particle backscatter at 355, 532 and 1064 nm, particle extinction at 355 and 532 nm and particle depolarization at 355 and 532 nm ( [8]). The accuracy of the measurements performed by BASIL is high enough to allow the retrieval of vertical profiles throughout the atmospheric CBL of the two turbulent variables (namely, water vapour mixing ratio and temperature) up to the fourth order during daytime.…”

Section: Methodsmentioning

confidence: 99%

Characterization of Turbulent Processes by the Raman Lidar System Basil in the Frame of the HD(CP)²Observational Prototype Experiment – Hope

Girolamo

Summa

Stelitano

et al. 2016

EPJ Web of Conferences

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Measurements carried out by the Raman lidar system BASIL are reported to demonstrate the capability of this instrument to characterize turbulent processes within the Convective Boundary Layer (CBL). In order to resolve the vertical profiles of turbulent variables, high resolution water vapour and temperature measurements, with a temporal resolution of 10 sec and a vertical resolution of 90 and 210 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of spectral and auto-covariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (IOP 5, 20 April 2013) from the HD(CP)2 Observational Prototype Experiment (HOPE), held in Central Germany in the spring 2013. The noise errors are demonstrated to be small enough to allow the derivation of up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations with sufficient accuracy.

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Raman lidar observations of a Saharan dust outbreak event: Characterization of the dust optical properties and determination of particle size and microphysical parameters

Cited by 65 publications

References 55 publications

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

Characterization of Turbulent Processes by the Raman Lidar System Basil in the Frame of the HD(CP)²Observational Prototype Experiment – Hope

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Raman lidar observations of a Saharan dust outbreak event: Characterization of the dust optical properties and determination of particle size and microphysical parameters

Cited by 65 publications

References 55 publications

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

Characterization of Turbulent Processes by the Raman Lidar System Basil in the Frame of the HD(CP)2Observational Prototype Experiment – Hope

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Characterization of Turbulent Processes by the Raman Lidar System Basil in the Frame of the HD(CP)²Observational Prototype Experiment – Hope