Fog Analysis during SOFOG3D Experiment

<p>Transportation especially aviation sector all around the world is severely hindered due to Fog and hence observations and specific research for fog is necessary. The SOFOG3D (SOuth west FOGs 3D) experiment took place in South-West of France which is particularly prone to fog occurrence, during the period between November 2019 to March 2020 with primary objective to advance our understanding of fog processes and to improve fog forecast. Simultaneous measurements from various remote sensing instruments like BASTA: a 95 GHz cloud radar with scanning capability, HATPRO Microwave radiometer (MWR), doppler lidar, and balloon-borne in-situ measurements were collected to characterize the spatio-temporal evolution of Fog. On the supersite, detailed measurements of meteorological conditions, aerosol properties, fog microphysics, water deposition, radiation budget, heat, and momentum fluxes are collected to provide 3D structure of the boundary layer during fog events. The improvement in the retrieval of fog parameters and understanding of fog dynamics based on cloud radar and microwave (MWR) synergy will be addressed. We will present our work on the retrieval of key fog parameters like dynamics and microphysics using a combination of cloud radar and MWR observations. The retrievals will be validated with the tethered-balloon and radio-sounding observations. In-situ measurements and remote-sensing retrievals of fog microphysical properties will be compared. We will show a detailed analysis of retrieved LWP derived from BASTA radar only with LWP derived from HATPRO microwave radiometer, considering instrumental uncertainty and sensitivity. A closer analysis of the in-situ data (measured by granulometer) will be presented in order to assess and improve the retrieval derived with cloud radar in vertically pointing mode. Radar attenuation will be quantified by measuring the backscattered radar signal on well-known calibrated reflectivity metallic targets installed at the top of 20 m mast. The integrated attenuation along the radar beam path will be measured by the cloud radar and used as a new constraint to improve the microphysical properties.</p>

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Aerosol optical and microphysical retrievals from a hybrid multiwavelength lidar data set – DISCOVER-AQ 2011

Atmospheric Measurement Techniques ◽

10.5194/amt-7-3095-2014 ◽

2014 ◽

Vol 7 (9) ◽

pp. 3095-3112 ◽

Cited By ~ 7

Author(s):

P. Sawamura ◽

D. Müller ◽

R. M. Hoff ◽

C. A. Hostetler ◽

R. A. Ferrare ◽

...

Keyword(s):

Remote Sensing ◽

In Situ Measurements ◽

Index Of Refraction ◽

High Spectral Resolution ◽

Lidar Data ◽

Data Set ◽

Microphysical Properties ◽

Lidar Measurements ◽

Multiwavelength Lidar

Abstract. Retrievals of aerosol microphysical properties (effective radius, volume and surface-area concentrations) and aerosol optical properties (complex index of refraction and single-scattering albedo) were obtained from a hybrid multiwavelength lidar data set for the first time. In July 2011, in the Baltimore–Washington DC region, synergistic profiling of optical and microphysical properties of aerosols with both airborne (in situ and remote sensing) and ground-based remote sensing systems was performed during the first deployment of DISCOVER-AQ. The hybrid multiwavelength lidar data set combines ground-based elastic backscatter lidar measurements at 355 nm with airborne High-Spectral-Resolution Lidar (HSRL) measurements at 532 nm and elastic backscatter lidar measurements at 1064 nm that were obtained less than 5 km apart from each other. This was the first study in which optical and microphysical retrievals from lidar were obtained during the day and directly compared to AERONET and in situ measurements for 11 cases. Good agreement was observed between lidar and AERONET retrievals. Larger discrepancies were observed between lidar retrievals and in situ measurements obtained by the aircraft and aerosol hygroscopic effects are believed to be the main factor in such discrepancies.

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Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-9289-2015 ◽

2015 ◽

Vol 8 (9) ◽

pp. 9289-9338 ◽

Cited By ~ 5

Author(s):

M. J. Granados-Muñoz ◽

J. A. Bravo-Aranda ◽

D. Baumgardner ◽

J. L. Guerrero-Rascado ◽

D. Pérez-Ramírez ◽

...

Keyword(s):

Remote Sensing ◽

Volume Concentration ◽

Mineral Dust ◽

In Situ Measurements ◽

Saharan Dust ◽

Night Time ◽

Passive Remote Sensing ◽

Microphysical Properties ◽

Multi Wavelength

Abstract. In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm−3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the estimated uncertainties. The differences in the volume concentration profiles, although somewhat larger, are still within the expected uncertainties.

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A comparative study of aerosol microphysical properties retrieved from ground-based remote sensing and aircraft in situ measurements during a Saharan dust event

Atmospheric Measurement Techniques ◽

10.5194/amt-9-1113-2016 ◽

2016 ◽

Vol 9 (3) ◽

pp. 1113-1133 ◽

Cited By ~ 21

Author(s):

María José Granados-Muñoz ◽

Juan Antonio Bravo-Aranda ◽

Darrel Baumgardner ◽

Juan Luis Guerrero-Rascado ◽

Daniel Pérez-Ramírez ◽

...

Keyword(s):

Remote Sensing ◽

Volume Concentration ◽

Mineral Dust ◽

In Situ Measurements ◽

Published Data ◽

Dust Event ◽

Data Set ◽

Passive Remote Sensing ◽

Microphysical Properties

Abstract. In this work we present an analysis of aerosol microphysical properties during a mineral dust event taking advantage of the combination of different state-of-the-art retrieval techniques applied to active and passive remote sensing measurements and the evaluation of some of those techniques using independent data acquired from in situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak at the Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on 27 June 2011. Column-integrated properties are provided by sun- and star-photometry, which allows for a continuous evaluation of the mineral dust optical properties during both day and nighttime. Both the linear estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during nighttime. LIRIC retrievals reveal the presence of dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 µm3 cm−3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in situ measurements. This study presents for the first time a comparison of the total volume concentration retrieved with LIRIC with independent in situ measurements, obtaining agreement within the estimated uncertainties for both methods and quite good agreement for the vertical distribution of the aerosol layers. Regarding the depolarization, the first published data set of the CAS-POL for polarization ratios is presented here and qualitatively compared with the lidar technique.

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The Retrieval of Ice-Cloud Properties from Cloud Radar and Lidar Synergy

Journal of Applied Meteorology ◽

10.1175/jam2229.1 ◽

2005 ◽

Vol 44 (6) ◽

pp. 860-875 ◽

Cited By ~ 47

Author(s):

Claire Tinel ◽

Jacques Testud ◽

Jacques Pelon ◽

Robin J. Hogan ◽

Alain Protat ◽

...

Keyword(s):

Extinction Coefficient ◽

Radar Data ◽

Mie Scattering ◽

In Situ Measurements ◽

Physical Parameters ◽

Backscatter Coefficient ◽

Blind Test ◽

Cloud Radar ◽

Microphysical Properties

Abstract Clouds are an important component of the earth’s climate system. A better description of their microphysical properties is needed to improve radiative transfer calculations. In the framework of the Earth, Clouds, Aerosols, and Radiation Explorer (EarthCARE) mission preparation, the radar–lidar (RALI) airborne system, developed at L’Institut Pierre Simon Laplace (France), can be used as an airborne demonstrator. This paper presents an original method that combines cloud radar (94–95 GHz) and lidar data to derive the radiative and microphysical properties of clouds. It combines the apparent backscatter reflectivity from the radar and the apparent backscatter coefficient from the lidar. The principle of this algorithm relies on the use of a relationship between the extinction coefficient and the radar specific attenuation, derived from airborne microphysical data and Mie scattering calculations. To solve radar and lidar equations in the cloud region where signals can be obtained from both instruments, the extinction coefficients at some reference range z0 must be known. Because the algorithms are stable for inversion performed from range z0 toward the emitter, z0 is chosen at the farther cloud boundary as observed by the lidar. Then, making an assumption of a relationship between extinction coefficient and backscattering coefficient, the whole extinction coefficient, the apparent reflectivity, cloud physical parameters, the effective radius, and ice water content profiles are derived. This algorithm is applied to a blind test for downward-looking instruments where the original profiles are derived from in situ measurements. It is also applied to real lidar and radar data, obtained during the 1998 Cloud Lidar and Radar Experiment (CLARE’98) field project when a prototype airborne RALI system was flown pointing at nadir. The results from the synergetic algorithm agree reasonably well with the in situ measurements.

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Single Aircraft Integration of Remote Sensing and In Situ Sampling for the Study of Cloud Microphysics and Dynamics

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-11-00044.1 ◽

2012 ◽

Vol 93 (5) ◽

pp. 653-668 ◽

Cited By ~ 94

Author(s):

Zhien Wang ◽

Jeffrey French ◽

Gabor Vali ◽

Perry Wechsler ◽

Samuel Haimov ◽

...

Keyword(s):

Remote Sensing ◽

Climate Models ◽

Microwave Radiometer ◽

Cloud Microphysics ◽

In Situ Data ◽

Microphysical Properties ◽

Remote Sensor ◽

Combined Use ◽

The University

Clouds are a critical component of the Earth's coupled water and energy cycles. Poor understanding of cloud–radiation–dynamics feedbacks results in large uncertainties in forecasting human-induced climate changes. Better understanding of cloud microphysical and dynamical processes is critical to improving cloud parameterizations in climate models as well as in cloud-resolving models. Airborne in situ and remote sensing can make critical contributions to progress. Here, a new integrated cloud observation capability developed for the University of Wyoming King Air is described. The suite of instruments includes the Wyoming Cloud Lidar, a 183- GHz microwave radiometer, the Wyoming Cloud Radar, and in situ probes. Combined use of these remote sensor measurements yields more complete descriptions of the vertical structure of cloud microphysical properties and of cloud-scale dynamics than that attainable through ground-based remote sensing or in situ sampling alone. Together with detailed in situ data on aerosols, hydrometeors, water vapor, thermodynamic, and air motion parameters, an advanced observational capability was created to study cloud-scale processes from a single aircraft. The Wyoming Airborne Integrated Cloud Observation (WAICO) experiment was conducted to demonstrate these new capabilities and examples are presented to illustrate the results obtained.

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Application of the shipborne remote sensing supersite OCEANET for profiling of Arctic aerosols and clouds during Polarstern cruise PS106

10.5194/amt-2019-434 ◽

2019 ◽

Author(s):

Hannes Jascha Griesche ◽

Patric Seifert ◽

Albert Ansmann ◽

Holger Baars ◽

Carola Barrientos Velasco ◽

...

Keyword(s):

Remote Sensing ◽

Sea Level ◽

Microwave Radiometer ◽

Value Added ◽

High Arctic ◽

Surface Processes ◽

The Arctic ◽

Target Classification ◽

Cloud Radar ◽

Microphysical Properties

Abstract. From 25 May to 21 July 2017, the research vessel Polarstern performed the cruise PS106 to the high Arctic in the region north and northeast of Svalbard. PS106 contributed observations for the initiative "Arctic Amplification: Climate Relevant Atmospheric and Surface Processes and Feedback Mechanisms (AC)3" which involves numerous projects aiming on understanding the role of atmospheric and surface processes in the ongoing rapid changes in the Arctic climate. As one of the central facilities of (AC)3, the mobile remote sensing platform OCEANET was deployed aboard Polarstern. Within a single container, OCEANET houses state-of-the-art remote sensing equipment, including a multi-wavelength Raman polarization lidar PollyXT and a 14-channel microwave radiometer HATPRO. For the cruise PS106 the measurements were supplemented by a motion-stabilized 35-GHz cloud radar Mira-35. This paper describes the treatment of technical challenges which were immanent during the deployment of OCEANET in the high Arctic. This includes the description of the motion stabilization of the cloud radar Mira-35 to ensure vertical-stare observations aboard the moving Polarstern. Also, low-level clouds and the presence of fog frequently prevented a continuous analysis of cloud conditions from synergies of lidar and radar within Cloudnet, because the technically determined lowest detection height of Mira-35 was 165m above sea level. To overcome this obstacle, an approach for identification of the cloud presence solely based on data from the near-field receiver of PollyXT at heights from 50m and 165m above sea level is presented. In addition, we provide an overview of the data processing chain of the OCEANET observations and demonstrate case studies of aerosol and cloud studies to introduce the capabilities of the dataset. The retrieval of aerosol optical and microphysical properties from the observations of PollyXT is presented by means of observations performed during the ice floe camp. Synergies between the remote sensing instruments and auxiliary observations from aboard Polarstern were analyzed by means of Cloudnet which provides as primary output a target classification mask. This target classification is the basis for value-added products such as liquid- and ice-cloud microphysical properties, cloud dynamics which can in subsequent steps be used as input for the investigation of cloud microphysical processes, radiative transfer calculations, or model evaluation. To this end, new approaches for ice crystal effective radius and eddy dissipation rates have been implemented into Cloudnet.

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