Simultaneous and synergistic profiling of cloud and drizzle properties using ground-based observations

Rusli, Stephanie; Donovan, D. P.; Russchenberg, H.W.J.

doi:10.5194/amt-10-4777-2017

Cited by 10 publications

(8 citation statements)

References 62 publications

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“…Unfortunately, Aydin and Lure (1991) do not show the size spectrum of δ. Nevertheless, as it is shown for lower frequencies (Matrosov et al, 1999;Ryzhkov, 2001;Trömel et al, 2013), and as we further show in Sect. 3.6, the spectrally resolved δ shows a similar oscillatory behavior to z DR .…”

Section: Separating Propagational and Backscattering Components Usingsupporting

confidence: 72%

Evaluation of the reflectivity calibration of W-band radars based on observations in rain

2020

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Abstract. This study presents two methods for evaluating the reflectivity calibration of W-band cloud radars. Both methods use natural rain as a reference target. The first approach is based on a self-consistency method of polarimetric radar variables, which is widely used in the precipitation radar community. As previous studies pointed out, the method cannot be directly applied to higher frequencies where non-Rayleigh scattering effects and attenuation have a nonnegligible influence on radar variables. The method presented here solves this problem by using polarimetric Doppler spectra to separate backscattering and propagational effects. New fits between the separated radar variables allow one to estimate the absolute radar calibration using a minimization technique. The main advantage of the self-consistency method is its lower dependence on the spatial variability in radar drop size distribution (DSD). The estimated uncertainty of the method is ±0.7 dB. The method was applied to three intense precipitation events, and the retrieved reflectivity offsets were within the estimated uncertainty range. The second method is an improvement on the conventional disdrometer-based approach, where reflectivity from the lowest range gate is compared to simulated reflectivity using surface disdrometer observations. The improved method corrects, first, for the time lag between surface DSD observations and the radar measurements at a certain range. In addition, the effect of evaporation of raindrops on their way towards the surface is mitigated. The disdrometer-based method was applied to 12 rain events observed by vertically pointed W-band radar and showed repeatable estimates of the reflectivity offsets at rain rates below 4 mm h−1 within ±0.9 dB. The proposed approaches can analogously be extended to Ka-band radars. Although very different in terms of complexity, both methods extend existing radar calibration evaluation approaches, which are inevitably needed for the growing cloud radar networks in order to provide high-quality radar observation to the atmospheric community.

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Section: Separating Propagational and Backscattering Components Usingsupporting

confidence: 72%

Evaluation of the reflectivity calibration of W-band radars based on observations in rain

2020

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“…Retrieving LWC in warm stratiform clouds requires information on the vertical structure of the hydrometeors, thus, often, is based on radar measurements (e.g., Atlas, 1954;Fox & Illingworth, 1997;Kogan et al, 2007;Sauvageot & Omar, 1987;Wang & Geerts, 2003) or a combination of radar with one or several additional instruments (e.g., Dong & Mace, 2003;Fielding et al, 2014;Frisch et al, 1995;Hogan et al, 2005;Huang et al, 2009;Li & Min, 2013;Löhnert et al, 2001;O'Connor et al, 2005;Rusli et al, 2017). A radar-independent method is the so-called linear-scaled approach distributing the column-integrated liquid water path (LWP) from a microwave radiometer (MWR) linearly, so that LWC is zero at cloud base and maximal at cloud top.…”

Section: Introductionmentioning

confidence: 99%

Revisiting Liquid Water Content Retrievals in Warm Stratified Clouds: The Modified Frisch

Küchler

Kneifel

Kollias

et al. 2018

Geophysical Research Letters

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Accurate observations of liquid water content (LWC) in warm stratiform clouds are important for quantifying their radiative and hydrological effects and for studying aerosol‐cloud interactions. Retrieving LWC from radar reflectivity under drizzling or nondrizzling conditions has been investigated for several decades by the cloud remote sensing community. However, no physically plausible framework exists to address the biases introduced by drizzle on existing retrieval techniques. We present the modified Frisch retrieval (ModFrisch), which combines radar and microwave radiometer measurements to retrieve LWC in both nondrizzling and drizzling conditions. It is shown, using a 1‐D steady state microphysical model and a radar simulator, that the uncertainty of ModFrisch is up to four times smaller than the uncertainty of similar retrievals under drizzling conditions, enabling LWC profiling with an accuracy of 20%. The performance of the ModFrisch technique is evaluated using 1 year of observations.

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“…File generated with AMS Word template 1.0 typically require additional observational constraints from shortwave radiometer (Fielding et al 2015) or microwave radiometer (Rusli et al 2017;Cadeddu et al 2020;Wu et al 2020). All these methods provide invaluable cloud and drizzle properties, but their retreival quality has not been evaluated against in-situ measurements.…”

mentioning

confidence: 99%

Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA)

Wang

Wood

Jensen

et al. 2022

Bulletin of the American Meteorological Society

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With their extensive coverage, marine low clouds greatly impact global climate. Presently, marine low clouds are poorly represented in global climate models, and the response of marine low clouds to changes in atmospheric greenhouse gases and aerosols remains the major source of uncertainty in climate simulations. The Eastern North Atlantic (ENA) is a region of persistent but diverse subtropical marine boundary layer clouds, whose albedo and precipitation are highly susceptible to perturbations in aerosol properties. In addition, the ENA is periodically impacted by continental aerosols, making it an excellent location to study the cloud condensation nuclei (CCN) budget in a remote marine region periodically perturbed by anthropogenic emissions, and to investigate the impacts of long-range transport of aerosols on remote marine clouds. The Aerosol and Cloud Experiments in Eastern North Atlantic (ACE-ENA) campaign was motivated by the need of comprehensive in-situ measurements for improving the understanding of marine boundary layer CCN budget, cloud and drizzle microphysics, and the impact of aerosol on marine low cloud and precipitation. The airborne deployments took place from June 21 to July 20, 2017 and January 15 to February 18, 2018 in the Azores. The flights were designed to maximize the synergy between in-situ airborne measurements and ongoing long-term observations at a ground site. Here we present measurements, observation strategy, meteorological conditions during the campaign, and preliminary findings. Finally, we discuss future analyses and modeling studies that improve the understanding and representation of marine boundary layer aerosols, clouds, precipitation, and the interactions among them.

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Simultaneous and synergistic profiling of cloud and drizzle properties using ground-based observations

Cited by 10 publications

References 62 publications

Evaluation of the reflectivity calibration of W-band radars based on observations in rain

Evaluation of the reflectivity calibration of W-band radars based on observations in rain

Revisiting Liquid Water Content Retrievals in Warm Stratified Clouds: The Modified Frisch

Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA)

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