Eugene E. Clothiaux's research while affiliated with Pennsylvania State University and other places
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Publications (178)
Plain Language Summary
Satellite observations are the backbone of modern weather forecast operations, especially for severe weather monitoring and prediction. However, they are also severely underutilized by computer weather models. Many satellite observations impacted by clouds and precipitation are not used in these models, despite their ability...
This article reviews Fuqing ZHANG’s contributions to mesoscale atmospheric science, from research to mentoring to academic service, over his 20-year career. His fundamental scientific contributions on predictability, data assimilation, and dynamics of high impact weather, especially gravity waves and tropical cyclones, are highlighted. His extremel...
Ensemble‐based data assimilation of radar observations across inner‐core regions of tropical cyclones (TCs) in tandem with satellite all‐sky infrared (IR) radiances across the TC domain improves TC track and intensity forecasts. This study further investigates potential enhancements in TC track, intensity, and rainfall forecasts via assimilation of...
Plain Language Summary
Using ERA‐Interim analyzed fields, we show how downward longwave radiation has changed at the Earth's surface from 1984 to 2017. The longwave radiation changes primarily occurred as a consequence of air temperature and water vapor changes. Air temperatures and water vapor amounts increased over most locations. The CO2 increas...
The article “Correlation Structures between Satellite All-Sky Infrared Brightness Temperatures and the Atmospheric State at Storm Scales”, written by Yunji ZHANG, Eugene E. CLOTHIAUX, and David J. STENSRUD was originally published electronically on the publisher’s internet portal on 30 of April 2021 without open access. With the author(s)’ decision...
Recent studies have shown that the assimilation of all-sky infrared (IR) observations can be beneficial for tropical cyclone analyses and predictions. The assimilation of Tail Doppler Radar (TDR) radial velocity observations has also been shown to improve tropical cyclone analyses and predictions; however, there is a paucity of literature on the im...
This study explores the structures of the correlations between infrared (IR) brightness temperatures (BTs) from the three water vapor channels of the Advanced Baseline Imager (ABI) onboard the GOES-16 satellite and the atmospheric state. Ensemble-based data assimilation techniques such as the ensemble Kalman filter (EnKF) rely on correlations to pr...
Recent studies have demonstrated advances in the analysis and prediction of severe thunderstorms and other weather hazards by assimilating infrared (IR) all-sky radiances into numerical weather prediction models using advanced ensemble-based techniques. It remains an open question how many of these advances are due to improvements in the radiance o...
The dynamics and predictability of the rapid intensification (RI) of Hurricane Harvey (2017) were examined using convection-permitting initialization, analysis, and prediction from a cycling ensemble Kalman filter (EnKF) that assimilated all-sky infrared radiances from the Advanced Baseline Imager on GOES-16. The EnKF analyses were able to evolve t...
Intrusions of warm, moist air into the Arctic during winter have emerged as important contributors to Arctic surface warming. Previous studies indicate that temperature, moisture, and hydrometeor enhancements during intrusions all make contributions to surface warming via emission of radiation down to the surface. Here, datasets from instrumentatio...
To better understand how model resolution affects the formation of Arctic boundary layer clouds, we investigated the influence of grid spacing on simulating cloud streets that occurred near Utqiaġvik (formerly Barrow), Alaska, on 2 May 2013 and were observed by MODIS (the Moderate Resolution Imaging Spectroradiometer). The Weather Research and Fore...
Observations collected over 3 months by the beam‐matched second‐generation Ka/W band Scanning Cloud Radar located at the Atmospheric Radiation Measurement Program Eastern North Atlantic observatory are used to advance existing liquid water content (LWC) retrieval techniques, quantify retrieval uncertainty, and subsequently characterize the impact o...
Improving our ability to predict future weather and climate conditions is strongly linked to achieving significant advancements in our understanding of cloud and precipitation processes. Observations are critical to making these advancements because they both improve our understanding of these processes and provide constraints on numerical models....
Stratocumulus clouds are important to the Arctic climate because they are prevalent and exert a strong radiative forcing on the surface. However, relatively little is known about how stratocumulus clouds form in the Arctic. In this study, radiative transfer calculations are used to show that the timescale over which stably stratified Arctic tempera...
Testing the often-made assumption that ice particle aggregates (snowflakes) are well represented by oblate spheroids, ellipsoid fits are applied to aggregate images. An algorithm to retrieve both the ellipsoidal parameters and the orientations of the fitted ellipsoids is applied to Multi-Angle Snowflake Camera measurements of ice particle aggregate...
General circulation model (GCM) evaluation using ground-based observations is complicated by inconsistencies in hydrometeor and phase definitions. Here we describe (GO)²-SIM, a forward simulator designed for objective hydrometeor-phase evaluation, and assess its performance over the North Slope of Alaska using a 1-year GCM simulation. For uncertain...
Large-eddy simulations of an observed single-layer Arctic mixed-phase cloud are analyzed to study the value of forward modeling of profiling millimeter wave cloud radar Doppler spectral width for model evaluation. Individual broadening terms and their uncertainties are quantified for the observed spectral width and compared to modeled broadening te...
General circulation model (GCM) evaluation using ground-based observations is complicated by inconsistencies in hydrometeor and phase definitions. Here we describe (GO)²-SIM, a forward-simulator designed for objective hydrometeor phase evaluation, and assess its performance over the North Slope of Alaska using a one-year GCM simulation. For uncerta...
Cloud microwave scattering properties for the Community Radiative Transfer Model (CRTM) have previously been created to be consistent with the particle size distributions specified by the WSM6 single‐moment microphysics scheme. Here, substitution of soft sphere scattering properties with non‐spherical particle scattering properties is explored in s...
(Beginning of WHAT, WHEN, WHERE Summary Box:) What: The work-shop gathered almost 50 scientists from Europe and the United States to discuss the progress towards developing electromagnetic scattering databases for ice and snow particles in the microwave region, their applications, the physical approximations used to compute these scattering propert...
The Community Radiative Transfer Model (CRTM) presently uses one look-up table (LUT) of cloud and precipitation single-scattering properties at microwave frequencies, with which any particle size distribution may interface via effective radius. This may produce scattering properties insufficiently representative of the model output if the microphys...
A simple numerical experiment was performed to investigate the result published in many papers that measurements indicate that aggregates may be well represented as oblate spheroids with mean aspect ratio (semiminor axis to semimajor axis length) of 0.6. The aspect ratio measurements are derived from two-dimensional projections of complex three-dim...
The atmospheric science community has entered a period in which radiative scattering properties in the microwave of realistically constructed ice particles are necessary for making progress on a number of fronts. One front includes retrieval of ice-particle properties and signatures from ground-, airborne- and satellite-based radar and radiometer o...
The potential impacts of GOES-R satellite radiances on tropical cyclone analysis and prediction were examined through ensemble correlations between simulated infrared brightness temperatures and various model state variables. The impacts of assimilating GOES-R all-sky infrared brightness temperatures on tropical cyclone analysis and prediction were...
Data is available at: http://dx.doi.org/10.5439/1258029
The Tropically Excited Arctic Warming (TEAM) mechanism ascribes warming of the Arctic surface to tropical convection, which excites poleward-propagating Rossby wave trains that transport water vapor and heat into the Arctic. A crucial component of the TEAM mechanism is the increase in downward infrared radiation (IR) that precedes the Arctic warmin...
Characteristics of graupel in an Arctic deep mixed-phase cloud on 7 December 2013 were identified with observations from an X-band scanning polarimetric radar and a Ka-band zenith pointing radar in conjunction with scattering calculations. The cloud system produced generating cells and strongly sheared precipitation fall streaks. The X-band radar h...
This study demonstrates that linear depolarization ratio (LDR) values obtained from zenith-pointing Ka-band radar Doppler velocity spectra are sufficient for detecting columnar ice crystals. During a deep precipitating system over the Arctic on 7 December 2013, the radar recorded LDR values up to -15 dB at temperatures corresponding to the columnar...
Scattering properties of a large collection of pristine ice crystals at millimeter and centimeter wavelengths are calculated using the generalized multiparticle Mie method. Millimeter- and centimeter-wavelength radar observables are also calculated by employing particle size distributions (PSDs) that ensure the bulk properties (e.g., ice water cont...
A modification to the Rayleigh-Gans approximation is made that includes self-interactions between different parts of an ice crystal, which both improves the accuracy of the Rayleigh-Gans approximation and extends its applicability to polarization dependent parameters. This modified Rayleigh-Gans approximation is both efficient and reasonably accura...
Retrieving and quantifying cloud-liquid drop contributions to radar returns from mixed-phase clouds remains a challenge because the radar signal is frequently dominated by the returns from the ice particles within the radar sample volume. We present a technique that extracts the weak cloud-liquid drop contributions from the total radar returns in p...
The microphysics and mesoscale structure of an Arctic shallow boundary layer cloud system observed during the May 2013 NSA-Radar IOP were examined using X-SAPR radar measurements. The shallow multilayer boundary layer cloud system was characterized by widely-distributed broken stratocumulus with cloud tops below 1 km with another layer a few 100 m...
The scanning Atmospheric Radiation Measurement (ARM) Program cloud radars (SACRs) are the primary instruments for documenting the four-dimensional structure and evolution of clouds within a 20-30-km radius of the ARM fixed and mobile sites. Here, the postprocessing of the calibrated SACR measurements is discussed. First, a feature mask algorithm th...
Retrieving and quantifying cloud-liquid drop contributions to radar returns from mixed-phase clouds remains a challenge because the radar signal is frequently dominated by the returns from the ice particles within the radar sample volume. We present a technique that extracts the weak cloud-liquid drop contributions from the total radar returns in p...
Cloud radar Doppler velocity spectra, lidar backscattering coefficients and depolarization ratios, and aircraft in situ measurements are used to investigate microphysical processes occurring in a case of multilayered, mixed-phase clouds over the North Slope of Alaska. Some liquid-cloud layers were observed to exist in well-mixed atmospheric layers,...
Using the Generalized Multi-particle Mie-method (GMM), Botta et al. (in
this issue) [7] created a database of backscattering cross sections for
412 different ice crystal dendrites at X-, Ka- and W-band wavelengths
for different incident angles. The Rayleigh-Gans theory, which
accounts for interference effects but ignores interactions between
differ...
Recent studies have reported unique characteristics of Arctic precipitation and clouds. For this study we used the X-band Scanning ARM Precipitation Radar (XSAPR) and Ka- and W-band Scanning ARM Cloud Radars (KASACR and WSACR) installed at Barrow, Alaska, and analyzed their reflectivities for two Arctic frontal snow cases: one case with liquid-clou...
To elucidate the characteristics of Arctic frontal snow cloud systems, the mesoscale structure of a frontal system passing through Barrow from 16–18 October 2012 was analyzed, taking advantage of the new radar systems deployed at Barrow. This same frontal system is further analyzed using the Weather Research and Forecasting (WRF) Model version 3.4....
Ice crystal scattering properties at microwave radar wavelengths can be modeled with the Generalized Multi-particle Mie (GMM) method by decomposing an ice crystal into a cluster of tiny spheres composed of solid ice. In this decomposition the mass distribution of the tiny spheres in the cluster is no longer equivalent to that in the original ice cr...
Detection of clouds in satellite-generated radiance images, including those from MODIS, is an important first step in many applications of these data. In this paper we apply spectral unmixing to this problem with the aim of estimating subpixel cloud fractions, as opposed to identification only of whether or not a pixel radiance contains cloud contr...
When stratiform-cloud-integrated radiative flux divergence (heating) is dependent on liquid water path (LWP) and droplet concentration Nd, feedbacks between cloud dynamics and this heating can exist. These feedbacks can be particularly strong for low LWP stratiform clouds, in which cloud-integrated longwave cooling is sensitive to LWP and Nd. Large...
Multimodality of cloud radar Doppler spectra is used to partition cloud particle phases and separate distinct ice populations in the radar sample volume, thereby facilitating the analysis of individual ice showers in multilayered mixed-phase clouds. A 35-GHz cloud radar located at Barrow, Alaska, during the Mixed-Phase Arctic Cloud Experiment colle...
The Multi-angle Imaging SpectroRadiometer (MISR) instrument has been collecting global Earth data from NASA's Terra satellite since February 2000. With its nine along-track view angles, four visible/near-infrared spectral bands, intrinsic spatial resolution of 275 m, and stable radiometric and geometric calibration, no instrument that combines MISR...
The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program has established a number of ARM Climate Research Facility (ACRF) and deployed an ARM Mobile Facility (AMF) in diverse climatic regimes around the world. The AMF has been deployed in diverse climatic regimes around the world to perform long-term continuous field measur...
The Multi-angle Imaging SpectroRadiometer (MISR) instrument has been collecting global Earth data from NASA's Terra satellite since February 2000. With its nine along-track view angles, four visible/near-infrared spectral bands, intrinsic spatial resolution of 275 m, and stable radiometric and geometric calibration, no instrument that combines MISR...
The National Centers for Environmental Prediction’s (NCEP) Eta Model, the models of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Aeronautics and Space Administration’s (NASA) Global Modeling and Assimilation Office (GMAO) models, and the Regional Atmospheric Modeling System (RAMS) model are all examined during the...
On February 24, 2000 ``first light'' on the MISR instrument ushered in a new era of terrestrial remote sensing. With 9 view angles ranging from 70 degrees backward to forward along Terra's flight track, near-simultaneous multiangle and multispectral images are acquired with moderately high spatial resolution, accurate and stable radiometric and geo...
The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program operate, 35-GHz millimeter-wavelength Cloud radars (MMCRs) in several climatologically distinct regions. The MMCRs, which are centerpiece instruments for the observation of clouds and precipitation, provide continuous. vertically resolved information on all hydrometeors a...
We develop a new estimation technique for recovering depth-of-field from multiple stereo images. Depth-of-field is estimated by determining the shift in image location resulting from different camera viewpoints. When this shift is not divisible by pixel width, the multiple stereo images can be combined to form a super-resolution image. By modeling...
The observation and representation in general circulation models (GCMs) of cloud vertical overlap are the objects of active research due to their impacts on the earth's radiative budget. Previous studies have found that vertically contiguous cloudy layers show a maximum overlap between layers up to several kilometers apart but tend toward a random...
Global climate models predict that the strongest dependences of surface air temperatures on increasing atmospheric carbon dioxide levels will occur in the Arctic. A systematic study of these dependences requires accurate Arctic-wide measurements, especially of cloud coverage. Thus cloud detection in the Arctic is extremely important, but it is also...
Climate and weather prediction models require accurate calculations of
vertical profiles of radiative heating. In contrast to calculations of
radiance and irradiance at the surface and top-of-atmosphere (TOA),
heating rate calculations cannot be directly validated due to the lack
of corresponding observations. However, surface and TOA measurements...
Ground-based two-channel microwave radiometers have been used for over 15 years by the Atmospheric Radiation Measurement (ARM) program to provide observations of downwelling emitted radiance from which precipitable water vapor (PWV) and liquid water path (LWP) – twp geophysical parameters critical for many areas of atmospheric research – are retrie...
Cumulus clouds can become tilted or elongated in the presence of wind shear. Nevertheless, most studies of the interaction of cumulus clouds and radiation have assumed these clouds to be isotropic. This paper describes an investigation of the effect of fair-weather cumulus cloud eld anisotropy on domain-averaged solar uxes and atmospheric heating r...
During the past 20 yr there has been substantial progress on the development and application of millimeter-wavelength (3.2 and 8.6 mm, corresponding to frequencies of 94 and 35 GHz) radars in atmospheric cloud research, boosted by continuous advancements in radar technology and the need to better understand clouds and their role in the Earth's clim...
The United States Department of Energy Atmospheric Radiation Measurement program operates millimeter-wavelength cloud radars in several climatologically distinct regions. The digital signal processors for these radars were recently upgraded and allow for enhancements in the operational parameters running on them. Recent evaluations of millimeter-wa...
The shape and tails of the probability distribution functions of the liquid water path in stratus clouds are expressed through a model encompassing Tsallis nonextensive statistics. A model originally proposed to describe turbulent flows describes the behavior of the normalized increments of the liquid water path, at both small and large timescales,...
A new method to retrieve cloud top heights stereoscopically using the dual-view facility of the Along Track Scanning Radiometer 2 (ATSR-2) instrument is assessed. This assessment is performed through a comparison of the cloud top heights obtained from ATSR-2 stereo and those derived from a 94-GHz radar, radiosonde profiles and independently from th...
Amongst the 36 spectral radiances available on the Moderate Resolution Imag-ing Spectroradiometer (MODIS) seven of them are used operationally for detection of clouds in daytime polar regions. While the information content of clouds inherent in spectral radiances is familiar, the information content of clouds contained in angular radiances (i.e., r...
The Detrended Fluctuation Analysis statistical method is applied to
microwave radiometer and infrared thermometer radiance data in order to examine
stratus cloud dynamics. The existence of long-range power law correlations in
stratus cloud liquid water path and radiance (brightness temperature)
fluctuations is demonstrated to occur over about a two...
1] The daytime cloud fraction derived by the Clouds and the Earth's Radiant Energy System (CERES) cloud algorithm using Moderate Resolution Imaging Spectroradiometer (MODIS) radiances over the Arctic from March 2000 through February 2004 increases at a rate of 0.047 per decade. The trend is significant at an 80% confidence level. The corresponding...
The Along-Track Scanning Radiometer 2 (ATSR2) instrument has a dual view capability that allows for stereo height retrievals. Stereo heights were retrieved for selected scenes over the United Kingdom Chilbolton Facility for Atmospheric and Radio Research and the United States Atmospheric Radiation Measurement program Southern Great Plains site from...
Using 35-GHz millimeter wave radar observations collected at the Southern Great Plains site of the Atmospheric Radiation Measurements (ARM) program, we study physical processes in cirrus cloud layers having different stratifications. The time-dependent probability distribution functions of the backscattering cross section within different layers in...
Radar cloud-top heights were retrieved at both the Chilbolton Facility for Atmospheric and Radio Research, UK (CFARR) and the ARM Southern Great Plain site, USA (SGP), using millimetre wave cloud radars and identical algorithms. The resulting cloud-top heights were used for comparison with MODIS and MISR retrieved cloud-top heights, from March 2000...
Shortwave and longwave 2D radiative transfer calculations were performed
using Monte Carlo radiative transfer models and output from a global
climate model (GCM) that employed, in each of its columns, a 2D cloud
system-resolving model (CSRM) with a horizontal grid-spacing Δx of
4 km. CSRM output were sampled every 9 hours for December 2000.
Radiati...
The interaction of clouds with solar and terrestrial radiation is one of the most important topics of climate research. In recent years it has been recognized that only a full three-dimensional (3D) treatment of this interaction can provide answers to many climate and remote sensing problems, leading to the worldwide development of numerous 3D radi...
The interaction of clouds with solar and terrestrial radiation is one of the most important topics of climate research. In recent years it has been recognized that only full three-dimensional (3D) treatment of this interaction can provide answers to many climate and remote sensing problems, leading to worldwide development of numerous 3D radiative...
![FIG. 7. Noise power estimates [presented as 10 log 10 (P n,ij )] vs...](profile/Pavlos-Kollias/publication/253124160/figure/fig5/AS:651156959289347@1532259325822/Noise-power-estimates-presented-as-10-log-10-P-n-ij-vs-left-SNR-and-right_Q320.jpg)
The U.S. Department of Energy (DOE) Atmospheric Radiation Measurements (ARM) program operates millimeter-wavelength cloud radars (MMCRs) in several specific locations within different climatological regimes. These vertically pointing cloud profiling radars supply the three most important Doppler spectrum moment estimates, which are the radar reflec...
Computation of components of shortwave (SW) or solar irradiance in the surface-atmospheric system forms the basis of intercomparison between 16 radiative transfer models of varying spectral resolution ranging from line-by-line models to broadband and general circulation models. In order of increasing complexity the components are: direct solar irra...
The Chilbolton 3-GHz Advanced Meteorological Radar (CAMRa), which is mounted on a
fully steerable 25 metre dish, can provide three-dimensional information on the presence of
hydrometeors. We investigate the potential for this radar to make useful measurements of
low-altitude liquid water cloud structure. In order to assess the cloud-height assignme...
Black carbon is ubiquitous in the atmosphere and is the main anthropogenic absorbing particulate. Absorption by black carbon is thought to be comparable to the cooling associated with sulfate aerosols, although present-day satellites are incapable of obtaining this measurement, and model estimates are highly uncertain. More measurements of black ca...
Horizontal grid-spacings in conventional atmospheric general circulation models (GCMs) are typically between 100 km and 500 km. Hence, many processes are unresolved and must be parameterized in terms of resolved variables. Development of satisfactory parameterizations of mean-field (or domain-average) cloud and radiative processes has been frustrat...
Clouds play a major role in controlling Earth's climate, and cloud detection is a crucial step in the numerical weather prediction, and global climate models. Multi-angle imaging spectroradiometer (MLSR) and moderate resolution imaging spectroradiometer (MODIS) were launched in 1999 by clouds. However, cloud detection algorithms using either MISR o...
A cloud optical depth retrieval algorithm that utilizes time series of solar irradiance and zenith downwelling radiance data collected at a fixed surface site is assessed using model-generated cloud fields and simulated radiation measurements. To date, the retrieval algorithm has only been assessed using instantaneous cloud fields in which time ser...
A 4-yr climatology (1997 2000) of warm boundary layer cloud properties is developed for the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) site. Parameters in the climatology include cloud liquid water path, cloud-base height, and surface solar flux. These parameters are retrieved from measurem...
This paper compares daytime cloud fraction derived from the Moderate Resolution Imaging Spectrometer (MODIS), an imager on the National Aeronautics and Space Administration's Earth Observing System Aqua and Terra platforms, to observations from a suite of surface-based instrumentation located at the Department of Energy's atmospheric radiation meas...
The full-spectrum correlated k-distribution (FSCK) method, originally developed for applications in combustion systems, is adapted for use in shortwave atmospheric radiative transfer. By weighting k distributions by the solar source function, the FSCK method eliminates the requirement that the Planck function be constant over a spectral interval. A...
Fast and accurate atmospheric radiation heating and cooling rate calculations are important for improving global climate and numerical weather prediction model performance. The radiative transfer calculations in atmospheric models must be fast so that the underlying methods can actually be implemented in the models and the calculations must be accu...
A prototype high-resolution oxygen A-band and water vapor band spectrometer (HAWS) has been developed and demonstrated to study the applicability of photon path length statistics in the remote sensing of clouds, aerosols, and water vapor. The HAWS successfully achieves an out-of-band rejection of better than 10-5, a resolution of better than 0.5 cm...
A 1-yr observational study of overcast boundary layer stratus at the U.S. Department of Energy Atmospheric Radiation Measurement Program Southern Great Plains site illustrates that surface radiation has a higher sensitivity to cloud liquid water path variations when compared to cloud drop effective radius variations. The mean, median, and standard...
An algorithm for retrieving the first two moments of the photon path length probability density function for both the oxygen A-band and the 0.820 μm water vapor band from measurements of the second generation Rotating Shadowband Spectrometer (RSS) is developed and applied to data from the Atmospheric Radiation Measurements (ARM) Program Southern Gr...
The primary purpose of this study is to assess the performance of 1D solar radiative transfer codes that are used currently both for research and in weather and climate models. Emphasis is on interpretation and handling of unresolved clouds. Answers are sought to the following questions: (i) How well do 1D solar codes interpret and handle columns o...
In order to test the strengths and limitations of cloud boundary retrievals from
radiosonde profiles, four years of radar, lidar and ceilometer data collected at the ARM SGP
site from November 1996 through October 2000 are used to assess the retrievals of Wang and
Rossow (1995; WR95) and Chernykh and Eskridge (1996; CE96). The lidar and ceilometer...
The state of the atmosphere is governed by the classical laws of fluid motion and exhibits correlations in various spatial and temporal scales. These correlations are crucial to understand the short and long term trends in climate. Cirrus clouds are important ingredients of the atmospheric boundary layer. To improve future parameterization of cirru...
Dynamical models with many degrees of freedom (i.e., spatial grid-points) that claim to be realistic should reproduce the structure and evolution of the geophysical fields they represent over a large range of spatial- and temporal scales, not just large domain averages and their slow tends in time. Atmospheric-, oceanic- and coupled general circula...
The EOS-TERRA MODIS and MISR instruments provide radiances for independent spectral and stereo retrievals of cloud top height (CTH), respectively. Collocated and coincident CTH retrievals were compared against each other and with coincident millimeter-wavelength cloud radar (MMCR) retrievals over the British Isles and the ARM SGP site. This inter-c...
Dual-antenna radar designs avoid using a transmit/receive switch. In order to measure radar reflectivity accurately and to avoid a general decrease in system sensitivity, these systems require precise alignment of their high-gain/narrow-beamwidth antennas, which is difficult. Given precisely aligned antennas, a parallax correction to account for an...
The complex structure of a typical stratus cloud base height (or profile) time series is analyzed with respect to the variability of its fluctuations and their correlations at all experimentally observed temporal scales. Due to the underlying processes that create these time series, they are expected to have multiscaling properties. For obtaining r...
A cloud particle size retrieval algorithm that uses radar reflectivity
factor and Doppler velocity obtained by a 35-GHz Doppler radar and
liquid water path estimated from microwave radiometer radiance
measurements is developed to infer the size distribution of stratus
cloud particles. Assuming a constant, but unknown, number concentration
with heig...
Citations
... Many critical physics upgrades in HWRF focused on the planetary boundary layer (PBL). In general, the PBL scheme was modified to better represent smaller scales while remaining consistent with large-scale fields from GFS (e.g., , 2017. The GFS PBL scheme used in HWRF's early years relied on the K-profile parameterization (KPP) in a well-mixed boundary layer, including the hurricane boundary layer. ...
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... Moreover, satellite-based SSR estimation products often have disadvantages such as the available duration of the dataset, coarse spatiotemporal resolution and uncertainties in accuracy (Gueymard and Ruiz-Arias, 2015;Ruiz-Arias and Gueymard, 2018). Therefore, reanalysis SSR products of global scale, long-term duration and high resolution have become important alternative data in relevant research fields (Huang et al., 2018;Clark et al., 2021;Yu et al., 2021;Wang et al., 2022). ...
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... Ka-band ARM Zenith Radar (KAZR), and Ceilometer (Morris, 2016;Widener et al., 2012) Cloud Thickness and profiles of rain rate below cloud base 1 min temporal and 50 m range resolution (Clothiaux et al., 2000;Ghate et al., 2021;Kollias et al., 2020) Radiosondes (Holdridge, 2020) PBL Height ...
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... One field of all-sky radiance assimilation research focuses on IR all-sky radiances from geostationary satellite imagers. The assimilation of IR all-sky BTs using an ensemble-based data assimilation technique, such as ensemble Kalman filter (EnKF) (Houtekamer & Zhang, 2016), has been proven to improve the forecasts of TCs (Feng & Pu, 2022;Hartman et al., 2021Hartman et al., , 2023Minamide & Zhang, 2018;, torrential rainfall (He et al., 2023;Honda, Kotsuki, et al., 2018;Okamoto et al., 2019;Otkin & Potthast, 2019), mid-latitude convection (Chandramouli et al., 2022;Degelia et al., 2023;Eure et al., 2023;Jones et al., 2020;Sawada et al., 2019;L. Zhu et al., 2023), and tropical convection Chan, Zhang, et al., 2020). ...
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... on of severe weather events, including extratropical cyclones (Jones et al., 2013(Jones et al., , 2014Otkin, 2012), tropical cyclones (F. Zhang, Minamide, & Clothiaux, 2016;Minamide & Zhang, 2018;Honda, Kotsuki, et al., 2018;Chan et al., 2020), tornadic supercells (Kerr et al., 2015;Jones et al., 2020;Chandramouli et al., 2022;Johnson et al., 2022;Y. Zhang et al., 2022), and mesoscale convective systems (MCSs) (Cintineo et al., 2016;Degelia et al., 2023;Jones et al., 2020;Zhu et al., 2023). ...
... Despite the challenges involved in infrared all-sky data assimilation, notable advancements have been achieved in assimilating cloud-affected radiances from infrared sensors; note that these infrared sensors are on board geostationary satellites (Feng & Pu, 2022;Minamide & Zhang, 2017;Okamoto, 2017;Zhang et al., 2019;Zhang, Stensrud, & Clothiaux, 2021). Okamoto (2017) proposed a symmetry parameter based on observed and simulated cloudy radiances to establish an observation error model for Advanced Himawari Imager observations. ...
... Improvements in ensemble intialisation and perturbation techniques will allow better representation of forecast uncertainties through adequate ensemble spread or divergence [22]. With many recent advances in space-borne and ground-based remote-sensing observations, mesoscale ensemble prediction systems also provide a potential platform for greater utilisation of these spatio-temporally dense but highly non-Gaussian observations through ensemble-based, or hybrid, data assimilation techniques [23]. These areas of potential future development would no doubt contribute to the improved prediction of high-impact weather over the GBA region and beyond. ...
... It is because the BRW station is a coastal station, so that its atmosphere contains abundant water vapor and sea salt aerosols originated from the sea. The water vapor and aerosols in the atmosphere will absorb the longwave radiation emitted from the surface at night, which plays a role in thermal insulation, thus increasing the daily minimum temperature (Sokolowsky et al., 2020). Furthermore, the large amount of water vapor and aerosols in the atmosphere of BRW would facilitate the formation of clouds, which may reduce the solar radiation reaching the ground surface during the daytime, leading to a lower daily maximum temperature, and also increase the minimum daily temperature by enhancing downward longwave radiation during the nighttime (Pyrgou et al., 2019). ...
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... This rapid evolution has frustrated attempts to fully capture their lifecycle using traditional measurements, like those obtained by NEXRAD. The TRACER and ESCAPE field campaigns achieved such sought-after observations of lifecycles of individual convective storms by implementing 1) RHI scans from two synchronized C-band scanning polarimetric radars, the CHIVO and the 2 nd generation C-band Scanning ARM Precipitation Radar (CSAPR2, Kollias et al., 2020). Using the MAAS framework, the C-band radars acquired high resolution scans of isolated convective cells with <30 s update times (Lamer et al., 2023;Dolan et al., 2023). ...
... In this respect, it is worth mentioning the agreement of the simulated and measured spectra when tested using an iterative scheme [19] or optimal estimation framework, using the DWR to constrain the estimation procedure [20]. To date, the preferred pair of wavelength combinations used for ground-based radar systems is the Ka-(λ = 8.6 mm) and W-band (λ = 3.2 mm) for ice [21], particles sizing, DSD estimation [19,20,24], rain rate [49] and liquid water content [44,47,50,51] quantitative estimation. Other wavelength combinations that have been used include the X-(λ = 3 cm) and W-band [27] and, more recently, K-and W-band [28,52], thus expanding the opportunities of further frequency combinations. ...
