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The deterministic motions of clouds and turbulence, despite their chaotic nature, nonetheless follow simple statistical power-law scalings: a fractal dimension D relates individual cloud perimeters p to measurement resolution, and turbulent fluctuations scale with separation distance through the Hurst exponent ℌ. It remains uncertain whether atmospheric turbulence is best characterized by split isotropy that is three-dimensional with ℌ = 1/3 at small scales and two-dimensional with ℌ = 1 at large scales, or by wide-range anisotropic scaling with an intermediate value of ℌ. Here, we introduce an "ensemble fractal dimension" De – analogous to D – that relates the total cloud perimeter per domain area 풫 as seen from space to measurement resolution, and show theoretically how turbulent dimensionality and cloud edge geometry are linked through ℌ = De − 1. Observationally, by progressively coarsening the resolution of cloud mask arrays from various global satellite platforms and a numerical simulation of a tropical domain we find the scaling De ~ 5/3, or ℌ ~ 2/3, a value nearly consistent with a previously proposed "23/9D" anisotropic turbulent scaling. Remarkably, the same scaling links two "limiting case" estimates of 풫 evaluated at the planetary scale and the Kolmogorov microscale, as separated by 11 orders of magnitude, suggesting that cloud and turbulent behaviors are constrained by basic planetary parameters. [ABSTRACT FROM AUTHOR]

Cloud area distributions are a defining feature of Earth's radiative exchanges with outer space. Cloud perimeter distributions n (p) are also interesting because the shared interface between clouds and clear sky determines exchanges of buoyant energy and air. Here, we test using detailed model output and a wide range of satellite datasets a first-principles prediction that perimeter distributions follow a scale-invariant power law n (p) ∝ p-(1+β) , where the exponent β = 1 is evaluated for perimeters within moist isentropic atmospheric layers. In model analyses, the value of β is closely reproduced. In satellite data, β is remarkably robust to latitude, season, and land–ocean contrasts, which suggests that, at least statistically speaking, cloud perimeter distributions are determined more by atmospheric stability than Coriolis forces, surface temperature, or contrasts in aerosol loading between continental and marine environments. However, the satellite-measured value of β is found to be 1.26 ± 0.06 rather than β = 1. The reason for the discrepancy is unclear, but comparison with a model reproduction of the satellite perspective suggests that it may owe to cloud overlap. Satellite observations also show that scale invariance governs cloud areas for a range at least as large as ∼ 3 to ∼ 3 × 10 5 km 2 , and notably with a corresponding power law exponent close to unity. Many prior studies observed a much smaller range for power law behavior, and we argue this difference is due to inappropriate treatments of the statistics of clouds that are truncated by the edge of the measurement domain. [ABSTRACT FROM AUTHOR]

BACKGROUND Patients undergoing Mohs micrographic surgery (MMS) are given detailed wound care instructions to prevent postoperative complications. Previous studies have revealed low treatment adherence in general dermatology, but adherence to postoperative wound care and its potential association with poor surgical outcomes remain largely unstudied. OBJECTIVE To determine the frequency and causes of wound care nonadherence in patients who underwent MMS. MATERIALS AND METHODS A questionnaire containing a modified Eight-Item Morisky Medication Adherence Measure Scale was administered to Mohs patients at their 1 to 2 weeks postoperative visit. RESULTS Sixty-three patients were solicited and consented to completing the questionnaire. The average modified Eight-Item Morisky Medication Adherence Measure Scale score was 7.4 of 8, indicating high adherence. Old age and wound care assistance were associated with increased adherence. Factors contributing to nonadherence included feeling well, being too busy, wound care causing discomfort, and being with friends or family. One patient (1.6%) with high adherence developed an epidermal inclusion cyst within the scar. No other complications were observed. CONCLUSION Most MMS patients demonstrated high adherence to wound care instructions, and nonadherence was not associated with postoperative complications. [ABSTRACT FROM AUTHOR]

The effect of aerosols on the properties of clouds is a large source of uncertainty in predictions of weather and climate. These aerosol‐cloud interactions depend critically on the ability of aerosol particles to form cloud droplets. A challenge in modeling aerosol‐cloud interactions is the representation of interactions between turbulence and cloud microphysics. Turbulent mixing leads to small‐scale fluctuations in water vapor and temperature that are unresolved in large‐scale atmospheric models. To quantify the impact of turbulent fluctuations on cloud condensation nuclei (CCN) activation, we used a high‐resolution Large Eddy Simulation of a convective cloud chamber to drive particle‐based cloud microphysics simulations. We show small‐scale fluctuations strongly impact CCN activity. Once activated, the relatively long timescales of evaporation compared to fluctuations causes droplets to persist in subsaturated regions, which further increases droplet concentrations. Plain Language Summary: Increases in cloud droplet number concentrations from human emissions of aerosol particles modify cloud properties, which strongly impacts Earth's energy balance. Large Eddy Simulations and Earth System Models are used to quantify these aerosol‐cloud interactions, but the spatial and temporal resolution of these models is too coarse to represent the impact of turbulence at the smallest scales. In this study, we show that small‐scale turbulent fluctuations lead to cloud droplet formation even when air is, on average, subsaturated, which would be impossible in conventional models of cloud microphysics. Our findings suggest that models that neglect turbulent fluctuations in supersaturation will underestimate cloud condensation nuclei activity under specific supersaturation regimes, which will may lead to error in modeled cloud properties. Key Points: Small‐scale turbulence leads to variability in the supersaturation experienced by aerosol particles and cloud droplets within cloudsTurbulent fluctuations increase cloud droplet formation at low supersaturation levels in comparison with uniform environmental conditionsAtmospheric models that neglect supersaturation variability due to turbulence may underestimate the number concentration of cloud droplets [ABSTRACT FROM AUTHOR]

Globally, clouds are known to warm the climate system in the thermal infrared because they typically emit thermal radiation to space at effective temperatures lower than the combined cloud‐free atmosphere and surface. However, here we show that ∼40% of low‐level clouds over sea ice tend to cool the Arctic system at TOA and contribute to a radiative cooling of the Arctic winter climate by −2.3 Wm−2, or a ∼16% reduction over the infrared warming effect of all clouds during winter. Based on satellite observations, low‐level clouds residing in surface‐based temperature inversions emit more longwave radiation to space than would occur in cloudless skies. While these clouds are known to significantly warm the surface, they cool the Arctic climate system overall. Our results imply that accurately representing the cloud radiative effects unique to the Arctic could help to constrain the regional energy budget. Plain Language Summary: The Arctic has become emblematic of climate change, with rapid warming that is at least twice as fast as the rest of the planet. However, major uncertainties in our confidence to understand and predict Arctic climate persist, particularly regarding the radiative effects of clouds. Here we use satellite data to quantify the radiative effects of Arctic low‐level clouds, and find approximately 40% of low‐level clouds over sea ice tend to radiatively cool the Arctic climate system (Earth's surface and the atmosphere) in winter, rather than warm the climate system as is typical for most clouds in the thermal infrared regime. This cooling effect is governed by the widespread surface temperature inversions (layers in which temperature increases with altitude), which cap these low‐level clouds and allow more longwave radiation to escape from the Earth to space compared to clear skies. This finding reveals a fundamental, but overlooked, characteristic of cloud radiative effects in the wintertime Arctic and establishes a new perspective for understanding Arctic climate change. Key Points: A full range of radiative effects for Arctic wintertime low clouds over sea ice is investigatedAbout 40% of low clouds over sea ice tends to cool the Arctic at the top of the atmosphere in the polar nightThese low clouds with a cooling effect at the top of the atmosphere reside within frequent surface‐based temperature inversions [ABSTRACT FROM AUTHOR]

The numbers of clouds of a given size is a defining feature of the earth's atmosphere. As well as cloud area, cloud perimeter p is interesting because it represents the length of the shared interface between clouds and clear-skies across which air and buoyant energy are dissipated. A recent study introduced a first-principles expression for the steady-state distribution of cloud perimeters, measured within a quasi-horizontal moist isentropic layer, that is a scale invariant power-law n(p) p-(1+β), where n(p) is the number density of cloud perimeters within [p,p+dp] and β = 1. This value of β was found to be in close agreement with output from a high-resolution, large eddy simulation of tropical convection. To further test this formulation, the current study evaluates n(p) within near-global imagery from nine full-disk and polar-orbiting satellites. A power-law is found to apply to measurements of n(p), and the value of β is observed to be remarkably robust to latitude, season, and land/ocean contrasts suggesting that, at least statistically speaking, cloud perimeter distributions are determined more by atmospheric stability than Coriolis forces, surface temperature, or contrasts in aerosol loading between continental andmarine environments. However, the measured value of β is found to be 1.29±0.05 rather than β = 1, indicating a relative scarcity of large clouds in satellite observations compared to theory and high-resolution cloud modeling. The reason for this discrepancy is unclear but may owe to the difference in perspective between evaluating n(p) along quasi-horizontal moist isentropes rather than looking down from space. As a test of this hypothesis, numerical simulation output shows that, while β ~ 1 within isentropes, higher values of β are reproduced for a simulated satellite view. However, the simulated value is a function of the cloud detection sensitivity where little such sensitivity is seen in satellite observations suggesting a possible misrepresentation of the physics controlling cloud sizes in simulations. A power-law also applies to satellite observations of cloud areas covering a range between ~3km² and ~3x105 km², a much wider range of scales than has been previously described in studies that we argue inappropriately treated the statistics of clouds truncated by the edge of a measurement domain. [ABSTRACT FROM AUTHOR]

The article focuses on the importance of integrating business education into dermatology residency programs. Topics include the significance of understanding the healthcare ecosystem for medical providers, teaching fundamental business principles to residents to inform decision-making, and the need for a standardized dermatology-specific curriculum that covers coding, billing, insurance, and other business-related aspects.

This paper is the second in a series in which kilometer-scale-resolving observations from the Atmospheric Radiation Measurement Program and output from the University of California, Los Angeles/Colorado State University cloud-resolving model (CRM) are used to evaluate the single-column model (SCM) version of the National Centers for Environmental Prediction Global Forecast System model. Part I demonstrated that kilometer-scale cirrus properties analyzed by applying the SCM's assumptions about cloud vertical overlap and horizontal homogeneity to its profiles of cloud water/ice mixing ratio, cloud fraction, and snow flux differed from the cloud radar observations while the CRM simulation reproduced most of the observed cirrus properties. The present study evaluates, through a comparison with the CRM, the SCM's representation of detrainment from deep cumulus and ice-phase microphysics in an effort to better understand the findings of Part I. This study finds that, although the SCM's detrainment rate profile averaged over the entire simulation period is comparable to the CRM's, detrainment in the SCM is comparatively sporadic and vertically localized. Too much detrained ice is sublimated when first detrained. Snow formed from detrained cloud ice falls through too deep of a layer. These aspects of the SCM's parameterizations may explain many of the differences in the cirrus properties between the SCM and the observations (or between the SCM and the CRM), and suggest several possible improvements for the SCM: 1) allowing multiple coexisting cumulus cloud types as in the original Arakawa-Schubert scheme, 2) prognostically determining the stratiform cloud fraction, and 3) explicitly predicting the snow mixing ratio. These would allow better representation of the detrainment from deep convection, better coupling of the volume of detrained air with cloud fraction, and better representation of snow flux.

Abstract: Before using a fluid dynamics physically based wildfire model to study wildfire, validation is necessary and model results need to be systematically and objectively analyzed and compared to real [...]

This study describes and demonstrates a new method for identifying deficiencies in how cloud processes are represented in large-scale models. Kilometer-scale-resolving cloud radar observations and cloud-resolving model (CRM) simulations were used to evaluate the representation of cirrus clouds in the single-column model (SCM) version of the National Centers for Environmental Prediction Global Forecast System model for a 29-day period during June and July 1997 at the Atmospheric Radiation Measurement Program site in Oklahoma. To produce kilometer-scale cirrus statistics from the SCM results, synthetic subgrid-scale (SGS) cloud fields were generated using the SCM's cloud fraction and hydrometeor content profiles, and the SCM's cloud overlap and horizontal inhomogeneity assumptions. Three sets of SCM synthetic SGS cloud fields were analyzed. Two NOSNOW sets were produced in which clouds did not include snow; one set used random overlap, the other, maximum/random. In the SNOW set, clouds included snow and random overlap was used. The three sets were sampled in the same way as the cloud-radar-detected cloud fields and the CRM-simulated cloud fields. The mean cirrus cloud occurrence frequency for the SCM NOSNOW cloud fields agrees with the observed value as well as the CRM's does, while that for SCM SNOW cloud fields is only half that observed. In most aspects, the SCM's cirrus properties differ significantly from the cloud radar's and the CRM's, which generally agree. In comparison, there are too many physically thin SCM NOSNOW cirrus layers (most occupy only a single model layer) and too many physically thick SCM SNOW cirrus layers (most are thicker than 4 km). For the optically thin subset of cirrus layers, 1) the mean, mode, and median ice water path, and layer-mean ice water content (IWC) values for the SCM are significantly larger than the observed and CRM values; 2) the SCM layer-mean IWCs decrease with cloud physical thickness, opposite to the observations and CRM results; and 3) the range of layer-mean effective radii in the SCM thin cirrus is too narrow.

A study conducted to find out whether, cardiac-resynchronization therapy is more beneficial with or without an implantable defibrillator, is presented. According to the study, when combined with an implantable defibrillator, cardiac-resynchronization therapy reduces mortality significantly.

Cloud radar data collected at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains site were used to evaluate the properties of cirrus clouds that occurred in a cloud-resolving model (CRM) simulation of the 29-day summer 1997 intensive observation period (IOP). The simulation was 'forced' by the large-scale advective temperature and water vapor tendencies, horizontal wind velocity, and turbulent surface fluxes observed at the Southern Great Plains site. The large-scale advective condensate tendency was not observed. The correlation of CRM cirrus amount with Geostationary Operational Environmental Satellite (GOES) high cloud amount was 0.70 for the subperiods during which cirrus formation and decay occurred primarily locally, but only 0.30 for the entire IOP. This suggests that neglecting condensate advection has a detrimental impact on the ability of a model (CRM or single-column model) to properly simulate cirrus cloud occurrence. The occurrence, vertical location, and thickness of cirrus cloud layers, as well as the bulk microphysical properties of thin cirrus cloud layers, were determined from the cloud radar measurements for June, July, and August 1997. The composite characteristics of cirrus clouds derived from this dataset are well suited for evaluating CRMs because of the close correspondence between the timescales and space scales resolved by the cloud radar measurements and by CRMs. The CRM results were sampled at eight grid columns spaced 64 km apart using the same definitions of cirrus and thin cirrus as the cloud radar dataset. The composite characteristics of cirrus clouds obtained from the CRM were then compared to those obtained from the cloud radar. Compared with the cloud radar observations, the CRM cirrus clouds occur at lower heights and with larger physical thicknesses. The ice water paths in the CRM's thin cirrus clouds are similar to those observed. However, the corresponding cloud-layer-mean ice water contents are significantly less than observed due to the CRM's larger cloud-layer thicknesses. The strong dependence of cirrus microphysical properties on layer-mean temperature and layer thickness as revealed by the observations is reproduced by the CRM. In addition, both the CRM and the observations show that the thin cirrus ice water path during large-scale ascent is only slightly greater than during no ascent or descent.

The single congestus case was set up to compare the Lagrangian and Eulerian microphysics methods in representing the cloud droplet size distribution (DSD) in a turbulent cloud environment. 2) The Lagrangian microphysics approach that offers a more natural way to study aerosol-cloud-precipitation interactions is becoming increasingly mature and is ready for simulations at subcloud and single-cloud scales. Keywords: Cloud microphysics; Clouds; Numerical analysis/modeling; Aerosol-cloud interaction EN Cloud microphysics Clouds Numerical analysis/modeling Aerosol-cloud interaction E1413 E1420 8 06/27/22 20220501 NES 220501 10th International Cloud Modeling Workshop B I What i : b More than 120 cloud modeling researchers participated in a virtual workshop to discuss recent progress in representing dynamics-microphysics interactions in numerical models and pathways to improve our understanding across a variety of scales. The case was simulated with four different idealized modeling setups: Cloud Model 1 (CM1; [3]) with two-moment NSSL microphysics ([25]), and Icosahedral Nonhydrostatic model (ICON; [43]) run in either 2D or 3D with two-moment bulk microphysics ([36]) or with McSnow Lagrangian microphysics ([1]). [Extracted from the article]

A microscale wildfire model, QES-Fire, that dynamically couples the fire front to microscale winds was developed using a simplified physics rate of spread (ROS) model, a kinematic plumerise model and a mass-consistent wind solver. The model is three-dimensional and couples fire heat fluxes to the wind field while being more computationally efficient than other coupled models. The plume-rise model calculates a potential velocity field scaled by the ROS model's fire heat flux. Distinct plumes are merged using a multiscale plume-merging methodology that can efficiently represent complex fire fronts. The plume velocity is then superimposed on the ambient winds and the wind solver enforces conservation of mass on the combined field, which is then fed into the ROS model and iterated on until convergence. QES-Fire's ability to represent plume rise is evaluated by comparing its results with those from an atmospheric large-eddy simulation (LES) model. Additionally, the model is compared with data from the FireFlux II field experiment. QES-Fire agrees well with both the LES and field experiment data, with domain-integrated buoyancy fluxes differing by less than 17% between LES and QES-Fire and less than a 10% difference in the ROS between QES-Fire and FireFlux II data. [ABSTRACT FROM AUTHOR]

A model used to study entrainment and mixing of thermodynamic properties in the stratus-topped boundary layer has been extended to represent these processes in cumulus clouds. The new model, called the 'explicit mixing parcel model' (EMPM), depicts finescale internal structure of a rising thermal in a cumulus cloud using a ID domain. The EMPM links the conventional parcel model, which has no internal structure, and multidimensional cloud models, which resolve cloud-scale structure produced by large eddies. In the EMPM, the internal structure evolves as a consequence of a sequence of discrete entrainment events and an explicit representation of turbulent mixing based on Kerstein's linear eddy model. In this version of the EMPM, subgrid-scale (eddy) diffusion is found to be adequate for representing the effects of the smallest turbulent eddies. In addition, a simple parameterization is used to determine the local condensation or evaporation rates. If the grid size is reduced so that the Kolmogorov scale is resolved and a droplet growth model is incorporated, the EMPM can predict the local microphysical environments of individual cloud droplets. To evaluate its entrainment parameterization, the EMPM was used to predict the bulk properties of Hawaiian cumulus cloud main turrets observed by aircraft. All of the quantities required by the EMPM except for the entrained blob size were obtained from the observations. Profiles of in-cloud means and variances of thermodynamic properties calculated by the EMPM for entrained blob sizes of 50 m, 100 m, and 200 m and by a parcel model with instantaneous mixing were compared to those observed. The observed mean conserved scalar profiles are reproduced by both mixing representations, but the observed mean liquid water mixing ratio and buoyancy profiles, all of the observed variance profiles, and the observed nonbuoyancy level are better reproduced by the EMPM. For entrained blob sizes of 100 m and 200 m, undiluted cloud base air reaches the inversion base in the EMPM, as was observed. These results indicate that the EMPM's entrainment parameterization is adequate for these cloud turrets, and that the characteristic entrained blob size is about 100 m. The model results also demonstrate that the finescale structure represented by the EMPM's 1D domain can be directly compared to high-frequency aircraft measurements.

A stratus-to-cumulus transition (SCT) that resembles observations occurred in Lagrangian numerical simulations of the subtropical marine boundary layer over the northeastern Pacific Ocean southwest of California. The Lagrangian approach involves translating the domain along the climatological boundary-layer trajectory at a rate equal to the observed surface wind speed. The SST is increased at a corresponding rate. The simulations did not include drizzle, the diurnal cycle, divergence changes, or mesoscale circulations and thus demonstrate that these processes are not essential for an SCT. A 2D numerical cloud model that can explicitly represent large convective eddies is used. Turbulence at scales smaller than the large eddies is parameterized using a third-moment turbulence closure. This type of model requires no cloud-regime-specific input and is computationally economical for multiday simulations. The results suggest that there are four stages in the transition from the stratus-topped boundary layer (STBL) to the trade cumulus boundary layer (TCBL). The simulated transition involves two intermediate stages: the deep stratus-topped boundary layer (DSTBL) and the 'cumulus-under-stratocumulus' boundary layer (CUSBL). The DSTBL, like the STBL, is well mixed. The CUSBL has a two-layer structure, like the TCBL, with a well-mixed subcloud layer and a stratified (partly mixed) cloud layer. The transition to a typical TCBL structure preceded the transition to a typical TCBL cloud fraction by about two days. Sensitivity tests indicate that by using diurnally averaged solar radiation with the daytime-averaged solar zenith angle, the model is able to reproduce the diurnally averaged cloud-top height. Tests also suggest that the boundary-layer structure is sensitive to the above-inversion thermodynamic structure.

The progression from the stratus-topped boundary layer (STBL) to the trade cumulus boundary layer (TCBL) during a simulated stratus-to-cumulus transition (SCT) involves two intermediate stages: the deep stratus-topped boundary layer (DSTBL) and the 'cumulus-under-stratocumulus' boundary layer (CUSBL). The DSTBL, like the STBL, has an active circulation that extends from the surface to the cloud top. The CUSBL, like the TCBL, has an active subcloud-layer circulation that is linked to the cloud layer by narrow cumulus updrafts. It is called a 'cumulus-coupled' boundary layer. A generally applicable convective updraft/downdraft partitioning scheme based on trajectory analysis was developed and used to analyze the boundary-layer circulation changes during the simulated SCT. The circulation analysis revealed that as the SST increased and the boundary layer changed from an STBL to a TCBL the updraft fraction in the cloud layer decreased, the convective updrafts strengthened, and the convective downdrafts weakened. The convective mass flux in the cloud layer decreased significantly as SST increased, while in the subcloud layer it changed little. The differences between updraft and downdraft properties and cloud-base levels gradually increased as SST increased. An analysis of the vertical acceleration components of the convective updrafts and downdrafts suggests that there are three steps in the transition from an STBL circulation to a TCBL circulation. First, the STBL deepens due to increased surface buoyancy fluxes as it moves over increasing SST but remains well mixed. Next, the DSTBL gradually changes into the two-layer CUSBL. During this step, negative buoyancy in downdrafts originating near cloud top becomes less important, while positive buoyancy in (cumulus) updrafts becomes more important. This indicates that cloud-top entrainment instability does not play a significant role in the SCT. Finally, the overlying stratocumulus deck gradually dissipates and only the underlying cumulus clouds of a typical TCBL remain. This general sequence of events is supported by recent observational evidence.

Modification of a commonly employed bulk ice-phase microphysics parameterization improves the simulation of few microphysical processes occurring in tropical anvil clouds. The modification includes the revision of the cloud ice growth by the Bergeron process and the associated formation of snow. Application of the modified procedure for numerical simulation of a tropical squall line reveals that these two changes increase the amount of cloud ice and the extent of anvil clouds to more realistic values.

Mixing of entrained air in stratus clouds is an important but poorly understood process. It is a crucial ingredient of cloud-top entrainment instability (CEI). CEI has been proposed as a breakup mechanism for stratus clouds. A recently developed model called the linear eddy model was used to simulate mixing of air entrained into stratus clouds. The linear eddy approach involves stochastic simulation on a one-dimensional domain with sufficient resolution to include all physically relevant length scales. In each realization, molecular diffusion is implemented explicitly, while a sequence of statistically independent 'rearrangement events' represents the effect of turbulent eddies. Inertial range scaling is incorporated. The linear eddy model was used to simulate the mixing of one or more wisps of entrained air with a specified volume of cloud-topped boundary layer (CTBL) air. The volume was idealized to be a horizontal slab of fluid that travels from the top of the CTBL down to the surface in the descending branch of a large convective eddy. The probability density function of the mixing fraction of entrained air was determined from linear eddy model simulations as a function of time for a mean mixing fraction of 0.05 and three wisp sizes. The effect of the mixing on the mean buoyancy of the downdraft could then be calculated given a specification of the buoyancy as a function of mixing fraction. In the simulations, the entrained air did not completely mix with cloudy air just below the CTBL top, nor was uniform saturation maintained. Furthermore, when buoyancy functions typical of observed CTBLs were used, the mean downdraft buoyancy due to entrainment and mixing integrated over the cloud layer remained positive. This suggests that CEI is unlikely in stratocumulus. An additional conclusion is that using reduced spatial resolutions typical of published large-eddy simulations (LES) of CTBLs in mixing simulations significantly underestimates the buoyancy in the cloud layer near cloud top. This may explain why low-resolution LES simulations have exhibited CEI under conditions for which CEI is not observed in the atmosphere.

The two-dimensional UCLA cumulus ensemble model (CEM), which covers a large horizontal area with a sufficiently small horizontal grid size, is used in this study. A number of simulation experiments are performed with the CEM to study the macroscopic behavior of cumulus convection under a variety of different large-scale and underlying surface conditions. Specifically, the modulation of cumulus activity by the imposed large-scale processes and the eddy kinetic energy (EKE) budget are investigated in detail. In all simulations, cumulus convection is rather strongly modulated by large-scale advective processes in spite of the existence of some nonmodulated high-frequency fluctuations. The modulation exhibits some phase delays, however, when the basic wind shear is strong. This is presumably associated with the existence of mesoscale convective organization. The EKE budget analysis shows that the net eddy buoyancy generation rate is nearly zero for a wide range of cumulus ensembles.

Sweet syndrome (SS), also known as acute febrile neutrophilic dermatosis, is an uncommon skin eruption characterized by fever, leukocytosis, and tender erythematous papules, nodules, and plaques. Histopathologically, SS lesions are characterized by marked superficial papillary edema with a dense neutrophilic infiltrate. SS is known to demonstrate both the Koebner phenomenon and pathergy. The majority of reported cases of these phenomena occur following significant cutaneous injury (e.g., biopsies, burns) rather than minor trauma such as pressure and friction. Here, we present the first known reported case of SS koebnerization secondary to minor grooming‐related hair plucking. In addition, this is also the first reported case to our knowledge of SS with perifollicular involvement on histopathology. [ABSTRACT FROM AUTHOR]

[Figure: see text]. [ABSTRACT FROM AUTHOR]

A unique and sudden need for virtual medical visits created by the coronavirus disease 2019 (COVID-19) pandemic has led to an unprecedented expansion of telemedicine across nearly all medical specialties in the United States. In addition to providing essential medical services during the pandemic, telemedicine has the potential to expand health care access to underserved populations by eliminating traditional barriers to care such as transportation needs, distance from specialty providers, and approved time off from work. However, the literature regarding telehealth accessibility for low-income, non-English-speaking, and minority patients remains limited. Through a cross-sectional analysis comparing 2019 clinic visits with 2020 telehealth visits at the UMass Memorial Medical Center, we demonstrate specialty-specific changes in patient demographics, including a younger population, fewer non-English-speaking patients, and a relative preservation of minority, Medicaid, and Medicare patients among telehealth visits in comparison to clinic visits. We also demonstrate that nonsurgical specialties had significantly lower no-show rates and the greatest number of telehealth visits. Overall, our findings highlight the potential shortcomings of telemedicine in servicing non-English-speaking patients, while maintaining that it is an important tool with the potential to improve access to health care, particularly in nonprocedural specialties. [ABSTRACT FROM AUTHOR]

One of the primary challenges associated with evaluating smoke models is the availability of observations. The limited density of traditional air quality monitoring networks makes evaluating wildfire smoke transport challenging, particularly over regions where smoke plumes exhibit significant spatiotemporal variability. In this study, we analyzed smoke dispersion for the 2018 Pole Creek and Bald Mountain Fires, which were located in central Utah. Smoke simulations were generated using a coupled fire‐atmosphere model, which simultaneously renders fire growth, fire emissions, plume rise, smoke dispersion, and fire‐atmosphere interactions. Smoke simulations were evaluated using PM2.5 observations from publicly accessible fixed sites and a semicontinuously running mobile platform. Calibrated measurements of PM2.5 made by low‐cost sensors from the Air Quality and yoU (AQ&U) network were within 10% of values reported at nearby air quality sites that used Federal Equivalent Methods. Furthermore, results from this study show that low‐cost sensor networks and mobile measurements are useful for characterizing smoke plumes while also serving as an invaluable data set for evaluating smoke transport models. Finally, coupled fire‐atmosphere model simulations were able to capture the spatiotemporal variability of wildfire smoke in complex terrain for an isolated smoke event caused by local fires. Results here suggest that resolving local drainage flow could be critical for simulating smoke transport in regions of significant topographic relief. Plain Language Summary: Smoke forecasts for wildfires in central Utah were evaluated using low‐cost air quality sensors and measurements from an instrument attached to a public transit train car. Preliminary results from this study suggest that calibrated low‐cost sensors can measure pollutant concentrations during wildfire smoke events within 10% of values measured by traditional air quality stations. A unique benefit of low‐cost sensor and mobile measurement networks is that they can delineate the edges of smoke plumes and are useful for identifying small‐scale processes that effect smoke plume dispersion. Smoke forecasts from a weather prediction model were able to capture the timing of a smoke plume, which inundated the Salt Lake Valley during the morning of 15 September 2018. However, local observations indicated that forecasted smoke was overpredicted by a factor of 2. Smoke forecast errors could potentially be attributed to fire growth errors in the fire spread model used within the weather prediction model. Key Points: Low‐cost sensors that are calibrated for smoke compares favorably to air quality stations that abide by Federal Equivalent MethodsNighttime drainage flow from nearby mountains can confine smoke plumes to the center of mountain valleys and advect in smoke free airHigh density, low‐cost air quality sensors can provide key insights on interactions between smoke plumes and local‐scale meteorology [ABSTRACT FROM AUTHOR]

Wintertime leads play an important role in the Arctic boundary layer as they promote turbulent flux exchanges from the warm exposed water to the cold atmosphere, thereby affecting the boundary layer cloudiness and structure. Recent work suggests that less (more) low‐level cloud occurrence is found in higher (lower) lead fraction periods, yet the analysis efforts were limited to a peripheral sea north of Barrow, Alaska. Here, we extend the previous study to examine this relationship between wintertime Arctic leads and low clouds in the context of a longer time series (November–March, 2006–2011) and greater spatial coverage (pan‐Arctic), based on cloud products from CloudSat and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellites and lead area fraction derived from Advanced Microwave Scanning Radiometer for EOS (AMSR‐E) observations. We focus on the east side of high‐pressure systems to isolate lead impacts on boundary layer clouds. Using a k‐means cluster‐analysis algorithm, low‐level cloud regimes are categorized on the basis of occurrence frequency of low‐level clouds. We find that, in the pan‐Arctic, less (more) low‐level cloud occurrence is associated with higher (lower) large‐scale lead flux, in agreement with the previous study. This lead‐low cloud association exhibits strong regional variation; it is enhanced over the Beaufort Sea where the variability of large‐scale meteorological conditions is decreased. These results suggest that a higher lead fraction might have important impacts on the Arctic surface energy budget by decreasing downwelling longwave radiation through reduced low‐level cloudiness. Key Points: Occurrence frequency of low‐level clouds decreases with increasing lead fraction over the pan‐Arctic during winterThis lead‐low cloud relation is particularly evident in the Beaufort Sea where there is less large‐scale meteorological variabilitySatellite‐detected large lead fractions largely consist of newly frozen leads that tend to dissipate low‐level clouds [ABSTRACT FROM AUTHOR]

A 40-year-old woman presented with painful ulcerations on the bilateral lower extremities. A biopsy confirmed the diagnosis of livedoid vasculopathy (LV). She was treated initially with aspirin and pentoxifylline, and with the addition of dipyridamole she has had no recurrence of her ulcerations to date. Despite this positive response to treatment she reported numbness and paresthesias in her legs. Nerve conduction studies confirmed a diagnosis of mononeuritis multiplex. This case highlights mononeuritis multiplex as a rarely described complication of LV, and suggests that early recognition of symptoms and a multidisciplinary approach are necessary for optimal management of this condition. [ABSTRACT FROM AUTHOR]

In a laboratory cloud chamber that is undergoing Rayleigh–Bénard convection, supersaturation is produced by isobaric mixing. When aerosols (cloud condensation nuclei) are injected into the chamber at a constant rate, and the rate of droplet activation is balanced by the rate of droplet loss, an equilibrium droplet size distribution (DSD) can be achieved. We derived analytic equilibrium DSDs and probability density functions (PDFs) of droplet radius and squared radius for conditions that could occur in such a turbulent cloud chamber when there is uniform supersaturation. We neglected the effects of droplet curvature and solute on the droplet growth rate. The loss rate due to fallout that we used assumes that (1) the droplets are well-mixed by turbulence, (2) when a droplet becomes sufficiently close to the lower boundary, the droplet's terminal velocity determines its probability of fallout per unit time, and (3) a droplet's terminal velocity follows Stokes' law (so it is proportional to its radius squared). Given the chamber height, the analytic PDF is determined by the mean supersaturation alone. From the expression for the PDF of the radius, we obtained analytic expressions for the first five moments of the radius, including moments for truncated DSDs. We used statistics from a set of measured DSDs to check for consistency with the analytic PDF. We found consistency between the theoretical and measured moments, but only when the truncation radius of the measured DSDs was taken into account. This consistency allows us to infer the mean supersaturations that would produce the measured PDFs in the absence of supersaturation fluctuations. We found that accounting for the truncation radius of the measured DSDs is particularly important when comparing the theoretical and measured relative dispersions of the droplet radius. We also included some additional quantities derived from the analytic DSD: droplet sedimentation flux, precipitation flux, and condensation rate. [ABSTRACT FROM AUTHOR]

In a laboratory cloud chamber that is undergoing Rayleigh-Bénard convection, supersaturation is produced by isobaric mixing. When aerosols (cloud condensation nuclei) are injected into the chamber at a constant rate, and the rate of droplet activation is balanced by the rate of droplet loss, an equilibrium droplet size distribution (DSD) can be achieved. We derived analytic equilibrium DSDs and PDFs of droplet radius and squared radius for conditions that could occur in such a turbulent cloud chamber when there is uniform supersaturation. The loss rate due to fall out that we used assumes that (1) the droplets are well-mixed by turbulence, (2) when a droplet becomes sufficiently close to the lower boundary, the droplet's terminal velocity determines its probability of fall out per unit time, and (3) a droplet's terminal velocity follows Stokes' Law (so it is proportional to its radius squared). Given the chamber height, the analytic PDF is determined by the mean supersaturation alone. From the expression for the PDF of the radius, we obtained analytic expressions for the first five moments of the radius, including moments for truncated DSDs. We used statistics from a set of measured DSDs to check for consistency with the analytic PDF. We found consistency between the theoretical and measured moments, but only when the truncation radius of the measured DSDs was taken into account. This consistency allows us to infer the mean supersaturations that would produce the measured PDFs in the absence of supersaturation fluctuations. We found that accounting for the truncation radius of the measured DSDs is particularly important when comparing the theoretical and measured relative dispersions of the droplet radius. We also included some additional quantities derived from the analytic DSD: droplet sedimentation flux, precipitation flux, and condensation rate. [ABSTRACT FROM AUTHOR]

The Pi Cloud Chamber offers a unique opportunity to study aerosol‐cloud microphysics interactions in a steady‐state, turbulent environment. In this work, an atmospheric large‐eddy simulation (LES) model with spectral bin microphysics is scaled down to simulate these interactions, allowing comparison with experimental results. A simple scalar flux budget model is developed and used to explore the effect of sidewalls on the bulk mixing temperature, water vapor mixing ratio, and supersaturation. The scaled simulation and the simple scalar flux budget model produce comparable bulk mixing scalar values. The LES dynamics results are compared with particle image velocimetry measurements of turbulent kinetic energy, energy dissipation rates, and large‐scale oscillation frequencies from the cloud chamber. These simulated results match quantitatively to experimental results. Finally, with the bin microphysics included the LES is able to simulate steady‐state cloud conditions and broadening of the cloud droplet size distributions with decreasing droplet number concentration, as observed in the experiments. The results further suggest that collision‐coalescence does not contribute significantly to this broadening. This opens a path for further detailed intercomparison of laboratory and simulation results for model validation and exploration of specific physical processes. Key Points: A large‐eddy simulation with spectral bin cloud microphysics is scaled to simulate a laboratory convection chamberThe simulated mixing state and turbulence properties reasonably compare with a simple flux model and with measurementsThe simulation replicates published observations from the Pi Chamber, including steady‐state clouds and size distribution broadening. [ABSTRACT FROM AUTHOR]