An Evaluation of a 94-GHz Radar for Remote Sensing of Cloud Properties

Clothiaux, Eugene E.; Miller, Mark A.; Albrecht, Bruce A.; Ackerman, Thomas P.; Verlinde, Johannes; Babb, David M.; Peters, Robert M.; Syrett, William J.

doi:10.1175/1520-0426(1995)012<0201:aeoagr>2.0.co;2

Cited by 164 publications

(97 citation statements)

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“…Multi-wavelength radars, and cloud radars in particular, present the most relevant platforms for obtaining comprehensive 3-D cloud structure, as well as composition and evolution (cf. Clothiaux et al, 1995;Baab et al, 1999;Kollias et al, 2007, Tridon et al, 2013 and references therein). The Cloud Profiling Radar (CPR) aboard CloudSat (Stephens et al, 2002), for example, has a vertical resolution of about 500 m (240 m for oversampled bin centers) and is the first space-borne radar to measure the vertical structure of clouds and light precipitation.…”

Section: Background and Motivationmentioning

confidence: 99%

Coupled Aerosol-Cloud Systems over Northern Vietnam during 7-SEAS/BASELInE: A Radar and Modeling Perspective

Loftus

Tsay

Pantina

et al. 2016

Aerosol Air Qual. Res.

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The 2013 7-SEAS/BASELInE campaign over northern Southeast Asia (SEA) provided, for the first time ever, comprehensive ground-based W-band radar measurements of the low-level stratocumulus (Sc) systems that often exist during the spring over northern Vietnam in the presence of biomass-burning aerosols. Although spatially limited, groundbased remote sensing observations are generally free of the surface contamination and signal attenuation effects that often hinder space-borne measurements of these low-level cloud systems. Such observations permit detailed measurements of structures and lifecycles of these clouds as part of a broader effort to study potential impacts of these coupled aerosolcloud systems on local and regional weather and air quality. Introductory analyses of the W-band radar data show these Sc systems generally follow a diurnal cycle, with peak occurrences during the nighttime and early morning hours, often accompanied by light precipitation. Preliminary results from idealized simulations of Sc development over land based on the observations reveal the familiar response of increased numbers and smaller sizes of cloud droplets, along with suppressed drizzle formation, as aerosol concentrations increase. Slight reductions in simulated W-band reflectivity values also are seen with increasing aerosol concentrations and result primarily from decreased droplet sizes. As precipitation can play a large role in removing aerosol from the atmosphere, and thereby improving air quality locally, quantifying feedbacks between aerosols and cloud systems over this region are essential, particularly given the negative impacts of biomass burning on human health in SEA. Such an endeavor should involve improved modeling capabilities along with comprehensive measurements of time-dependent aerosol and cloud profiles.

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Section: Background and Motivationmentioning

confidence: 99%

Coupled Aerosol-Cloud Systems over Northern Vietnam during 7-SEAS/BASELInE: A Radar and Modeling Perspective

Loftus

Tsay

Pantina

et al. 2016

Aerosol Air Qual. Res.

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“…At each radar profile, the receiver noise is identified and a preliminary binary feature mask is estimated using a power threshold. Using a rangeelevation spatial filter, a refined feature mask is estimated (Clothiaux et al, 1995;Hildebrand and Sekhon, 1974).…”

Section: Observation and Raw Data Post-processingmentioning

confidence: 99%

Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

Lamer

Tatarevic

et al. 2014

Atmos. Meas. Tech.

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Abstract. The scanning Atmospheric Radiation Measurement (ARM) cloud radars (SACRs) provide continuous atmospheric observations aspiring to capture the 3-D cloudscale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a suggested scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range-Height Indicator -CW-RHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Southern Great Plains and Cape Cod sites are post-processed (detection mask, gaseous attenuation correction, insect filtering and velocity de-aliasing). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimensions. Next the Cartesian-gridded Doppler velocity fields are decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith-pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D cloud dynamical representations up to 25-30 degrees off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics and anisotropy and lead to more realistic 3-D radiative transfer calculations.

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“…The theory of cloud detection by millimeter radar can be found in Doviak and Zrnic (1993) and Clothiaux et al (1995) and is briefly introduced below.…”

Section: Background Of Warm Cloud Microphysics Retrievalmentioning

confidence: 99%

An intercomparison of radar-based liquid cloud microphysics retrievals and implications for model evaluation studies

et al. 2012

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Abstract. This paper presents a statistical comparison of three cloud retrieval products of the Atmospheric Radiation Measurement (ARM) program at the Southern Great Plains (SGP) site from 1998 to 2006: MICROBASE, University of Utah (UU), and University of North Dakota (UND) products. The probability density functions of the various cloud liquid water content (LWC) retrievals appear to be consistent with each other. While the mean MICROBASE and UU cloud LWC retrievals agree well in the middle of cloud, the discrepancy increases to about 0.03 gm −3 at cloud top and cloud base. Alarmingly large differences are found in the droplet effective radius (r e ) retrievals. The mean MICROBASE r e is more than 6 µm lower than the UU r e , whereas the discrepancy is reduced to within 1 µm if columns containing raining and/or mixed-phase layers are excluded from the comparison. A suite of stratified comparisons and retrieval experiments reveal that the LWC difference stems primarily from rain contamination, partitioning of total liquid later path (LWP) into warm and supercooled liquid, and the input cloud mask and LWP. The large discrepancy among the r e retrievals is mainly due to rain contamination and the presence of mixed-phase layers. Since rain or ice particles are likely to dominate radar backscattering over cloud droplets, the large discrepancy found in this paper can be thought of as a physical limitation of single-frequency radar approaches. It is therefore suggested that data users should use the retrievals with caution when rain and/or mixed-phase layers are present in the column.

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An Evaluation of a 94-GHz Radar for Remote Sensing of Cloud Properties

Cited by 164 publications

References 0 publications

Coupled Aerosol-Cloud Systems over Northern Vietnam during 7-SEAS/BASELInE: A Radar and Modeling Perspective

Coupled Aerosol-Cloud Systems over Northern Vietnam during 7-SEAS/BASELInE: A Radar and Modeling Perspective

Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

An intercomparison of radar-based liquid cloud microphysics retrievals and implications for model evaluation studies

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