bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Outcomes following Left Atrial Appendage Occlusion: A Single-Center Experience
Authors: Adedinsewo Demilade , Salwa Najiyah , Sennhauser Susie , Farhat Salman , Winder Jeffery , Lesser Elizabeth , White Launia , Landolfo Carolyn , Venkatachalam K.L. , Pollak Peter , Parikh Pragnesh
Published: August 2020

Introduction: Percutaneous left atrial appendage closure is an established alternative to anticoagulation therapy for stroke prophylaxis among patients with nonvalvular atrial fibrillation. There are currently no guidelines on the choice of antithrombotic therapy following placement of the Watchman® device, the optimal time to discontinue anticoagulation or the duration of follow-up imaging after device deployment. Our main objective was to evaluate clinical outcomes among these patients. Methods: We conducted a retrospective review of patients who received a Watchman® device at Mayo Clinic sites between January 2010 and December 2018. We constructed Cox-proportional hazard models to evaluate the effect of specific variables on clinical outcomes. Results: 231 patients were identified (33% female), median age was 77 years, CHA2DS2-VASc score was 5 and HASBLED score was 4. We found no difference in clinically significant bleeding based on initial antithrombotic choice. However, patients with prior gastrointestinal bleeding were more likely to have a bleeding event in the first 6 weeks following Watchman® implantation (HR 9.40, 95% CI 2.15–41.09). Device sizes of 24–27 mm were significantly associated with a decreased risk of thromboembolic events (HR 0.15, 95% CI 0.04–0.55) compared to 21-mm devices. Peridevice leak (PDL) sizes appeared to either remain the same or increase on follow-up imaging. Discussion/Conclusions: This observational study showed no statistically significant difference in bleeding risk related to initial antithrombotic choice. Smaller device sizes were associated with thromboembolic events, and longitudinal PDL assessment using transesophageal echocardiography showed these frequently do not decrease in size. Larger studies are needed.
National and Local Strategies in the Netherlands for Obesity Prevention and Management in Children and Adolescents
Authors: Seidell Jacob C. , Halberstadt Jutka
Published: August 2020

Background: As in many other countries around the world, the Netherlands has a high prevalence of overweight and obesity in children. About 1 in 7 of children aged 2–19 years has either overweight or obesity. Summary: In this paper the national and local activities aimed at the prevention and management of obesity in children and adolescents in the Netherlands are reviewed. It is recommended to, nationally as well as locally, take an integrated-systems approach that tackles the obesogenic food environment as well as upstream and downstream determinants of obesity. Efforts should take a life course approach and be focused on promoting obesity prevention as well as improving the management of children who already have obesity. The national policies in the Netherlands rely heavily on self-regulation by stakeholders such as supermarkets, restaurants, and the food industry. Local policies and actions such as the whole-systems approach in Amsterdam are promising. Future directions include development of tools for the operationalization and evaluation of local systems approaches. Regulation by national and local governments is necessary to ensure a healthy food environment for children and their families, but health policies require intersectoral action. Key Messages: In the Netherlands many policies are in place or under development, especially at the municipal level (e.g., in Amsterdam), but more substantial action is urgently required.
Automatic Classification of Anterior Chamber Angle Based on Ultrasound Biomicroscopy Images
Authors: Yu Jian , Li Wanyue , Chen Qian , Deng Guohua , Jiang Chunhui , Liu Guangxing , Shi Guohua , Sun Xinghuai
Published: August 2020

Introduction: Evaluating the anterior chamber angle (ACA) is important for the early diagnosis and treatment of primary angle-closure glaucoma. The assessment of ultrasound biomicroscopy (UBM) images usually requires well-trained ophthalmologists and screening for patients with narrow ACA is usually time- and labor-intensive. Therefore, the automatic assessment of UBM could be cost-effective and valuable in daily practice. Objective: The objective of this study is to develop an automatic method for localizing and classifying ACA based on UBM images. Methods: UBM images were collected and a coarse-to-fine method was used to localize the apex of the angle recess. By analyzing the grayscale features around the angle recess, closed angles were identified, and the rest were then classified as open or narrow angles, based on the degree of ACA. Using manual classification as the reference standard, the overall accuracy (OAcc), sensitivity (Sen), specificity (Spe), and balanced accuracy of the automatic classification method were evaluated. Results: A total of 540 UBM images from 290 participants were analyzed. Using these UBM images and the proposed method, the ACA was classified as open, narrow, or closed. During processing, the method localized the angle recess with 95% accuracy. The OAcc of the ACA classification was 77.8%, and the Spe and Sen of our method were 85.8 and 81.7% for angle closure; 88.9 and 75.6% for open angles; 91.9 and 76.1% for narrow angles, respectively. Conclusions: Our method of automatic angle localization and classification based on UBM images is feasible and reliable. The automatic classification of ACA provides a basis and reference for future studies.
Combination of a Probiotic and an Antispasmodic Increases Quality of Life and Reduces Symptoms in Patients with Irritable Bowel Syndrome: A Pilot Study
Authors: Barraza-Ortiz Diego A. , Pérez-López Nuria , Medina-López Víctor M. , Minero-Alfaro José I. , Zamarripa-Dorsey Felipe , Fernández-Martínez Nerina del C. , Llorente-Ramón Alberto , Ramos-Aguilar Gustavo A.
Published: August 2020

Background: Probiotics and antispasmodics have been tested extensively in the management of symptoms of irritable bowel syndrome (IBS), but they have rarely been evaluated in combination. The objective of this pilot study was to assess the efficacy of treatment with the probiotic formulation i3.1 (Lactobacillus plantarum CECT7484 and CECT7485 and Pediococcus acidilactici CECT7483), with or without the addition of the antispasmodic alverine/simethicone, in improving IBS-related quality of life (QoL) and reducing abdominal pain and diarrhea in patients with IBS. Methods: This was a randomized, placebo-controlled clinical trial with 3 parallel arms (probiotic, probiotic plus antispasmodic, and placebo). Patients with IBS (N = 55) were recruited at the Gastroenterology Department of the Juárez Hospital (México City). QoL was assessed with the IBS-QoL questionnaire, abdominal pain with a visual analog scale, and stool consistency with the Bristol scale. Results: The IBS-QoL rate of response (ITT analysis) was 50.0% for patients in the group with probiotic alone, 68.4% in the group with probiotic plus antispasmodic, and 16.7% in the group with placebo after 6 weeks of treatment (p = 0.005). Response to abdominal pain was reported by 38.9% of patients treated with probiotic, 57.9% with probiotic plus antispasmodic, and 16.7% with placebo (p = 0.035). Regarding stool consistency, a response to treatment was reported by 44.4% of patients treated with probiotic, 57.9% with probiotic plus antispasmodic, and 16.7% with placebo (p = 0.032). Conclusion: The results are consistent with previous studies on the use of the i3.1 probiotic formulation for the management of symptoms in IBS patients, and the addition of an antispasmodic improves its observed effects.
The reality of inclusion in physical education in the Brazilian school system
Authors: Castro Eliane Mauerberg de , Figueiredo Gabriella Andreetta , Campbell Debra Frances
Published: August 2020

Our purpose in this article was threefold. First, we attempted to analyze evidences of inclusion in the Brazilian school, and we argued that inclusion still is a long road ahead, particularly, in the field of physical education. In relation to inclusion, we used data provided by the Brazilian government itself to demonstrate several issues of concern, including some with educational governing bodies. Second, we examined how the Brazilian physical education national curriculum parameters have been tailored in their pedagogical recommendations to accommodate the “movement culture” approach. Although physical educators endorsed the new curricular directives, their practice in school with inclusion revealed troublesome situations. Overall, they admitted that they did not feel prepared to work with students with disability in their classes, and they feel that they need continuing education, as well as actual administrative/government investments. Third, we introduced concepts from dynamic systems theory to our adapted physical education practice while working with people with disabilities in inclusive settings. We illustrated the theory in its application to the physical education practices by reporting a lifetime of work in outreach programs in the field of adapted physical activity (APA), at São Paulo State University at Rio Claro. The complexities in the practice of inclusive school physical education require a holistic approach, which we feel can be accomplished through the employment of dynamic systems concepts. Whether epistemological directions include the movement culture approach or dynamic systems theory, or a hybrid, these efforts must be sustained by committed teachers, the school system, government leaders, families, and the entire community.
Knockout of SORBS2 Protein Disrupts the Structural Integrity of Intercalated Disc and Manifests Features of Arrhythmogenic Cardiomyopathy
Authors: Ding Yonghe , Yang Jingchun , Chen Peng , Lu Tong , Jiao Kunli , Tester David J. , Giudicessi John R. , Jiang Kai , Ackerman Michael J. , Li Yigang , Wang Dao Wu , Lee HoN‐chi , Wang Dao Wen , Xu Xiaolei
Published: August 2020

Background

Sorbs2b
(sorbin and SH3 domain‐containing 2b) was recently identified as a cardiomyopathy gene from a zebrafish mutagenesis screen. However, cardiac functions of its mammalian ortholog remain elusive.

Methods and Results

We conducted a detailed expression and subcellular localization analysis of Sorbs2 ortholog in mice and a phenotypic characterization in Sorbs2 knockout mice.
Sorbs2
is highly expressed in the mouse heart and encodes an adhesion junction/desmosome protein that is mainly localized to the intercalated disc. A mutation with near complete depletion of the Sorbs2 protein in mice results in phenotypes characteristic of human arrhythmogenic cardiomyopathy (ACM), including right ventricular dilation, right ventricular dysfunction, spontaneous ventricular tachycardia, and premature death. Sorbs2 is required to maintain the structural integrity of intercalated disc. Its absence resulted in profound cardiac electrical remodeling with impaired impulse conduction and action potential derangements. Targeted sequencing of human patients with ACM identified 2 rare splicing variants classified as likely pathogenic were in 2 unrelated individuals with ACM from a cohort of 59 patients with ACM.

Conclusions

The Sorbs2 knockout mouse manifests several key features reminiscent of human ACM. Although the candidacy of
SORBS2
as a new ACM‐susceptibility gene is supported by preliminary human genetics study, future validation in larger cohorts with ACM is needed.
Canthigaster aziz, a new deep-dwelling toby fish (Tetraodontiformes: Tetraodontidae) from the Red Sea
Authors: MATSUURA KEIICHI , BOGORODSKY SERGEY V. , MAL AHMAD O. , ALPERMANN TILMAN J.
Published: August 2020

A new species of toby fish, Canthigaster aziz, is described based on a single specimen collected from the northern Red Sea off Saudi Arabia. The holotype was trawled from a depth of 315 m, the second deepest record for the genus. The new species is distinguished from other species of the genus by the following combination of characters: 8 dorsal-fin rays; 8 anal-fin rays; 15 pectoral-fin rays; dorsal-fin origin opposite to anal-fin origin; five diffuse, saddle-like, black blotches along dark yellowish dorsal edge of body between nape and dorsal-fin origin; dorsal half of body light brown with concentrated dark pigments just behind eye and with a longitudinal, irregular, pale golden stripe running from area just behind eye to dorsal side of caudal peduncle; ventral half of posterior part of body pinkish with tiny subcutaneous black spots; head and ventral half of body before anus white; and all fins uniformly pale grey. A phylogenetic analysis of the mitochondrial COI barcoding region resulted in a new and unique evolutionary lineage for the new species that is sister to a clade composed of C. leoparda, C. pygmaea and C. valentini. It also shows C. aziz to be evolutionary deeply divergent from its closest congeners. In addition to the description of the new species, comparisons with congeners and a revised key to the Indo-Pacific species are provided.
Long Memory and Time Trends in Particulate Matter Pollution (PM2.5 and PM10) in the 50 U.S. States
Authors: Gil-Alana Luis A. , Yaya OlaOluwa S. , Awolaja Oladapo G. , Cristofaro Lorenzo
Published: August 2020

This paper focuses on the analysis of the time series behavior of the air quality in the 50 U.S. states by looking at the statistical properties of particulate matter (PM10and PM2.5) datasets. We use long daily time series of outdoor air quality indices to examine issues such as the degree of persistence as well as the existence of time trends in data. For this purpose, we use a long-memory fractionally integrated framework. The results show significant negative time trend coefficients in a number of states and evidence of long memory in the majority of the cases. In general, we observe heterogeneous results across counties though we notice higher degrees of persistence in the states on the west with respect to those on the east, where there is a general decreasing trend. It is hoped that the findings in the paper will continue to assist in quantitative evidence-based air quality regulation and policies.
Atmospheric Subseasonal Variability and Circulation Regimes: Spectra, Trends, and Uncertainties
Authors: Žagar Nedjeljka , Zaplotnik Žiga , Karami Khalil
Published: August 2020

The globally integrated subseasonal variability associated with the two main atmospheric circulation regimes, the balanced (or Rossby) and unbalanced (or inertia–gravity) regimes, is evaluated for the four reanalysis datasets: ERA-Interim, JRA-55, MERRA, and ERA5. The results quantify amplitudes and trends in midlatitude traveling and quasi-stationary Rossby wave patterns as well as in the equatorial wave activity across scales. A statistically significant reduction of subseasonal variability is found in Rossby waves with zonal wavenumber k = 6 along with an increase in variability in wavenumbers k = 3–5 in the summer seasons of both hemispheres. The four reanalyses also agree regarding increased variability in the large-scale Kelvin waves, mixed Rossby–gravity waves, and westward-propagating inertio-gravity waves with the lowest meridional mode. The amplitude and sign of trends in inertia–gravity modes with smaller zonal scales and greater meridional modes differ between the ERA-Interim and JRA-55 datasets on the one hand and the ERA5 and MERRA data on the other. An increased variability in the ERA-Interim and JRA-55 accounts for positive trends in their total subseasonal variability.
Stone Content Influence on Land Surface Model Simulation of Soil Moisture and Evapotranspiration at Reynolds Creek Watershed
Authors: Parajuli Kshitij , Jones Scott B. , Tarboton David G. , Hipps Lawrence E. , Zhao Lin , Sadeghi Morteza , Rockhold Mark L. , Torres-Rua Alfonso , Flerchinger Gerald N.
Published: August 2020

Considerable advancement in spatiotemporal resolution of remote sensing and ground-based measurements has enabled refinement of parameters used in land surface models for simulating surface water fluxes. However, land surface modeling capabilities are still inadequate for accurate representation of subsurface properties and processes, which continue to limit the accuracy of land surface model simulation. Our objective in this study was to examine the performance of the variously parameterized Noah land surface model with multiphysics option (Noah-MP) in simulating evapotranspiration (ET) and soil moisture dynamics in stony soils using verification from eddy covariance ET and in situ soil moisture data during the growing season of year 2015, obtained from the Lower Sheep subcatchment within the Reynolds Creek Experimental Watershed in southwestern Idaho. We evaluated the performance of Noah-MP considering four different scenarios with 1) a one-layer soil profile with Noah-MP default soil hydraulic parameters and three more five-layer soil profiles using 2) Noah-MP default soil hydraulic parameters; 3) soil hydraulic parameters derived from a pedotransfer function using field observations; and 4) hydraulic parameters from scenario 3, which also accounted for stone content in each layer. Each modeling experiment was forced with the same set of initial conditions, atmospheric input, and vegetation parameters. Our results indicate that enhanced representation of soil profile properties and stone content information noticeably improve the Noah-MP land surface model simulation of soil moisture content and evapotranspiration.
Projected Changes of Precipitation Characteristics Depend on Downscaling Method and Training Data: MACA versus LOCA Using the U.S. Northeast as an Example
Authors: Wang Guiling , Kirchhoff Christine J. , Seth Anji , Abatzoglou John T. , Livneh Ben , Pierce David W. , Fomenko Lori , Ding Tengyu
Published: August 2020

This study compares projected changes of precipitation characteristics in the U.S. Northeast in two analog-based climate downscaling products, Multivariate Adaptive Constructed Analogs (MACA) and Localized Constructed Analogs (LOCA). The level of similarity or differences between the two products varies with the type of precipitation metrics. For the total precipitation amount, the two products project significant annual increases that are similar in magnitude, spatial pattern, and seasonal distribution, with the largest increases in winter and spring. For the overall precipitation intensity or temporal aggregation of heavy precipitation (e.g., number of days with more than one inch of precipitation, the simple intensity index, and the fraction of annual precipitation accounted for by heavy events), both products project significant increases across the region with strong model consensus; the magnitude of absolute increases are similar between the two products, but the relative increases are larger in LOCA due to an underestimation of heavy precipitation in LOCA’s training data. For precipitation extremes such as the annual maximum 1-day precipitation, both products project significant increases in the long-term mean, but the magnitude of both the absolute and relative changes are much smaller in LOCA than in MACA, indicating that the extreme precipitation differences in the training data are amplified in future projections as a result of the analog-based downscaling algorithms. The two products differ the most in the intensity and frequency of rare extremes (e.g., 1-in-20-years events) for which MACA projects significant increases while the LOCA-projected changes are inconclusive over much of the study area.
Assessing the Impact of Soil Layer Depth Specification on the Observability of Modeled Soil Moisture and Brightness Temperature
Authors: Shellito Peter J. , Kumar Sujay V. , Santanello Joseph A. , Lawston-Parker Patricia , Bolten John D. , Cosh Michael H. , Bosch David D. , Holifield Collins Chandra D. , Livingston Stan , Prueger John , Seyfried Mark , Starks Patrick J.
Published: August 2020

The utility of hydrologic land surface models (LSMs) can be enhanced by using information from observational platforms, but mismatches between the two are common. This study assesses the degree to which model agreement with observations is affected by two mechanisms in particular: 1) physical incongruities between the support volumes being characterized and 2) inadequate or inconsistent parameterizations of physical processes. The Noah and Noah-MP LSMs by default characterize surface soil moisture (SSM) in the top 10 cm of the soil column. This depth is notably different from the 5-cm (or less) sensing depth of L-band radiometers such as NASA’s Soil Moisture Active Passive (SMAP) satellite mission. These depth inconsistencies are examined by using thinner model layers in the Noah and Noah-MP LSMs and comparing resultant simulations to in situ and SMAP soil moisture. In addition, a forward radiative transfer model (RTM) is used to facilitate direct comparisons of LSM-based and SMAP-based L-band Tb retrievals. Agreement between models and observations is quantified using Kolmogorov–Smirnov distance values, calculated from empirical cumulative distribution functions of SSM and Tb time series. Results show that agreement of SSM and Tb with observations depends primarily on systematic biases, and the sign of those biases depends on the particular subspace being analyzed (SSM or Tb). This study concludes that the role of increased soil layer discretization on simulated soil moisture and Tb is secondary to the influence of component parameterizations, the effects of which dominate systematic differences with observations.
High-Resolution (2.5 km) Ensemble Precipitation Analysis across Canada
Authors: Khedhaouiria Dikra , Bélair Stéphane , Fortin Vincent , Roy Guy , Lespinas Franck
Published: August 2020

Consistent and continuous fields provided by precipitation analyses are valuable for hydrometeorological applications and land data assimilation modeling, among others. Providing uncertainty estimates is a logical step in the analysis development, and a consistent approach to reach this objective is the production of an ensemble analysis. In the present study, a 6-h High-Resolution Ensemble Precipitation Analysis (HREPA) was developed for the domain covering Canada and the northern part of the contiguous United States. The data assimilation system is the same as the Canadian Precipitation Analysis (CaPA) and is based on optimal interpolation (OI). Precipitation from the Canadian national 2.5-km atmospheric prediction system constitutes the background field of the analysis, while at-site records and radar quantitative precipitation estimates (QPE) compose the observation datasets. By using stochastic perturbations, multiple observations and background field random realizations were generated to subsequently feed the data assimilation system and provide 24 HREPA members plus one control run. Based on one summer and one winter experiment, HREPA capabilities in terms of bias and skill were verified against at-site observations for different climatic regions. The results indicated HREPA’s reliability and skill for almost all types of precipitation events in winter, and for precipitation of medium intensity in summer. For both seasons, HREPA displayed resolution and sharpness. The overall good performance of HREPA and the lack of ensemble precipitation analysis (PA) at such spatiotemporal resolution in the literature motivate further investigations on transitional seasons and more advanced perturbation approaches.
Changes in Future Flash Flood–Producing Storms in the United States
Authors: Dougherty Erin , Rasmussen Kristen L.
Published: August 2020

Flash floods are high-impact events that can result in massive destruction, such as the May 2010 flash floods in the south-central United States that resulted in over $2 billion of damage. While floods in the current climate are already destructive, future flood risk is projected to increase based on work using global climate models. However, global climate models struggle to resolve precipitation structure, intensity, and duration, which motivated the use of convection-permitting climate models that more accurately depict these precipitation processes on a regional scale due to explicit representation of convection. These high-resolution convection-permitting simulations have been used to examine future changes to rainfall, but not explicitly floods. This study aims to fill this gap by examining future changes to rainfall characteristics and runoff in flash flood–producing storms over the United States using convection-permitting models under a pseudo–global warming framework. Flash flood accumulated rainfall increases on average by 21% over the United States in a future climate. Storm-generated runoff increases by 50% on average, suggesting increased runoff efficiency in future flash flood–producing storms. In addition to changes in nonmeteorological factors, which were not explored in this study, increased future runoff is possible due to the 7.5% K−1 increase in future hourly maximum rain rates. Though this median change in rain rates is consistent with Clausius–Clapeyron theory, some storms exhibit increased future rain rates well above this, likely associated with storm dynamics. Overall, results suggest that U.S. cities might need to prepare for more intense flash flood–producing storms in a future climate.
Impact of Land Initial States Uncertainty on Subseasonal Surface Air Temperature Prediction in CFSv2 Reforecasts
Authors: Shin Chul-Su , Dirmeyer Paul A. , Huang Bohua , Halder Subhadeep , Kumar Arun
Published: August 2020

The NCEP CFSv2 ensemble reforecasts initialized with different land surface analyses for the period of 1979–2010 have been conducted to assess the effect of uncertainty in land initial states on surface air temperature prediction. The two observation-based land initial states are adapted from the NCEP CFS Reanalysis (CFSR) and the NASA GLDAS-2 analysis; atmosphere, ocean, and ice initial states are identical for both reforecasts. This identical-twin experiment confirms that the prediction skill of surface air temperature is sensitive to the uncertainty of land initial states, especially in soil moisture and snow cover. There is no distinct characteristic that determines which set of the reforecasts performs better. Rather, the better performer varies with the lead week and location for each season. Estimates of soil moisture between the two land initial states are significantly different with an apparent north–south contrast for almost all seasons, causing predicted surface air temperature discrepancies between the two sets of reforecasts, particularly in regions where the magnitude of initial soil moisture difference lies in the top quintile. In boreal spring, inconsistency of snow cover between the two land initial states also plays a critical role in enhancing the discrepancy of predicted surface air temperature from week 5 to week 8. Our results suggest that a reduction of the uncertainty in land surface properties among the current land surface analyses will be beneficial to improving the prediction skill of surface air temperature on subseasonal time scales. Implications of a multiple land surface analysis ensemble are also discussed.
Ertel Potential Vorticity versus Bernoulli Potential on Approximately Neutral Surfaces in the Antarctic Circumpolar Current
Authors: Stanley Geoffrey J. , Dowling Timothy E. , Bradley Mary E. , Marshall David P.
Published: August 2020

We investigate the relationship between Ertel potential vorticity Q and Bernoulli potential B on orthobaric density surfaces in the Antarctic Circumpolar Current (ACC), using the Southern Ocean State Estimate. Similar to the extratropical atmospheres of Earth and Mars, Q and B correlate in the ACC in a function-like manner with modest scatter. Below the near-surface, the underlying function relating Q and B appears to be nearly linear. Nondimensionalizing its slope yields “Ma,” a “Mach” number for long Rossby waves, the ratio of the local flow speed to the intrinsic long Rossby wave speed. We empirically estimate the latter using established and novel techniques that yield qualitatively consistent results. Previous work related “Ma” to the degree of homogeneity of Q and to Arnol’d’s shear stability criteria. Estimates of “Ma” for the whole ACC are notably positive, implying inhomogeneous Q, on all circumpolar buoyancy surfaces studied. Upper layers generally exhibit “Ma” slightly less than unity, suggesting that shear instability may operate within these layers. Deep layers exhibit “Ma” greater than unity, implying stability. On surfaces shallower than 1000 m just north of the ACC, the Q versus B slope varies strongly on subannual and interannual time scales, but “Ma” hovers near unity. We also study spatial variability: the ACC is speckled with hundreds of small-scale features with “Ma” near unity, whereas away from the ACC “Ma” is more commonly negative or above unity, both corresponding to stability. Maps of the time-mean “Ma” show stable regions occupy most of the Southern Ocean, except for several topographically controlled hotspots where “Ma” is always near unity.
Hydraulics and Mixing of the Deep Overflow in the Lifamatola Passage of the Indonesian Seas
Authors: Tan Shuwen , Pratt Larry J. , Yuan Dongliang , Li Xiang , Wang Zheng , Li Yao , Corvianawatie Corry , Surinati Dewi , Budiman Asep S. , Bayhaqi Ahmad
Published: August 2020

Hydrographic measurements recently acquired along the thalweg of the Lifamatola Passage combined with historical moored velocity measurements immediately downstream of the sill are used to study the hydraulics, transport, mixing, and entrainment in the dense overflow. The observations suggest that the mean overflow is nearly critical at the mooring site, suggesting that a weir formula may be appropriate for estimating the overflow transport. Our assessment suggests that the weir formulas corresponding to a rectangular, triangular, or parabolic cross section all result in transports very close to the observation, suggesting their potential usage in long-term monitoring of the overflow transport or parameterizing the transport in numerical models. Analyses also suggest that deep signals within the overflow layer are blocked by the shear flow from propagating upstream, whereas the shallow wave modes of the full-depth continuously stratified flow are able to propagate upstream from the Banda Sea into the Maluku Sea. Strong mixing is found immediately downstream of the sill crest, with Thorpe-scale-based estimates of the mean dissipation rate within the overflow up to 1.1 × 10−7 W kg−1 and the region-averaged diapycnal diffusivity within the downstream overflow in the range of 2.3 × 10−3 to 10.1 × 10−3 m2 s−1. Mixing in the Lifamatola Passage results in 0.6–1.2-Sv (1 Sv ≡ 106 m3 s−1) entrainment transport added to the overflow, enhancing the deep-water renewal in the Banda Sea. A bulk diffusivity coefficient estimated in the deep Banda Sea yields 1.6 × 10−3 ± 5 × 10−4 m2 s−1, with an associated downward turbulent heat flux of 9 W m−2.
The Scale of Submesoscale Baroclinic Instability Globally
Authors: Dong Jihai , Fox-Kemper Baylor , Zhang Hong , Dong Changming
Published: August 2020

The spatial scale of submesoscales is an important parameter for studies of submesoscale dynamics and multiscale interactions. The horizontal spatial scales of baroclinic, geostrophic-branch mixed layer instabilities (MLI) are investigated globally (without the equatorial or Arctic oceans) based on observations and simulations in the surface and bottom mixed layers away from significant topography. Three high-vertical-resolution boundary layer schemes driven with profiles from a MITgcm global submesoscale-permitting model improve robustness. The fastest-growing MLI wavelength decreases toward the poles. The zonal median surface MLI wavelength is 51–2.9 km when estimated from the observations and from 32, 25, and 27 km to 2.5, 1.2, and 1.1 km under the K-profile parameterization (KPP), Mellor–Yamada (MY), and κ–ε schemes, respectively. The surface MLI wavelength has a strong seasonality with a median value 1.6 times smaller in summer (10 km) than winter (16 km) globally from the observations. The median bottom MLI wavelengths estimated from simulations are 2.1, 1.4, and 0.41 km globally under the KPP, MY, and κ–ε schemes, respectively, with little seasonality. The estimated required ocean model grid spacings to resolve wintertime surface mixed layer eddies are 1.9 km (50% of regions resolved) and 0.92 km (90%) globally. To resolve summertime eddies or MLI seasonality requires grids finer than 1.3 km (50%) and 0.55 km (90%). To resolve bottom mixed layer eddies, grids finer than 257, 178, and 51 m (50%) and 107, 87, and 17 m (90%) are estimated under the KPP, MY, and κ–ε schemes.
Heat Transport through Diurnal Warm Layers
Authors: Hughes Kenneth G. , Moum James N. , Shroyer Emily L.
Published: August 2020

Penetration of solar radiation in the upper few meters of the ocean creates a near-surface, stratified diurnal warm layer. Wind stress accelerates a diurnal jet in this layer. Turbulence generated at the diurnal thermocline, where the shear of the diurnal jet is concentrated, redistributes heat downward via mixing. New measurements of temperature and turbulence from fast thermistors on a surface-following platform depict the details of this sequence in both time and depth. Temporally, the sequence at a fixed depth follows a counterclockwise path in logϵ–logN parameter space. This path also captures the evolution of buoyancy Reynolds number (a proxy for the anisotropy of the turbulence) and Ozmidov scale (a proxy for the outer vertical length scale of turbulence in the absence of the free surface). Vertically, the solar heat flux always leads to heating of fluid parcels in the upper few meters, whereas the turbulent heat flux divergence changes sign across the depth of maximum vertical temperature gradient, cooling fluid parcels above and heating fluid parcels below. In general, our measurements of fluid parcel heating or cooling rates of order 0.1°C h−1 are consistent with our estimates of heat flux divergence. In weak winds (<2 m s−1), sea surface temperature (SST) is controlled by the depth-dependent absorption of solar radiation. In stronger winds, turbulent mixing controls SST.
Mitigation of Geostationary Lightning Mapper Geolocation Errors
Authors: Virts Katrina S. , Koshak William J.
Published: August 2020

The geolocation of lightning flashes observed by spaceborne optical sensors depends upon a priori assumptions of the cloud-top height (or, more generally, the height of the radiant emitter) as observed by the satellite. Lightning observations from the Geostationary Lightning Mappers (GLMs) on Geostationary Operational Environmental Satellite 16 (GOES-16) and GOES-17 were originally geolocated by assuming that the global cloud-top height can be modeled as an ellipsoidal surface with an altitude of 16 km at the equator and sloping down to 6 km at the poles. This method produced parallax errors of 20–30 km or more near the limb, where GLM can detect side-cloud illumination or below-cloud lightning channels at lower altitudes than assumed by the ellipsoid. Based on analysis of GLM location accuracy using a suite of alternate lightning ellipsoids, a lower ellipsoid (14 km at the equator, 6 km at the poles) was implemented in October and December 2018 for GLM-16 and GLM-17, respectively. While the lower ellipsoid slightly improves overall GLM location accuracy, parallax-related errors remain, particularly near the limb. This study describes the identification of optimized assumed emitter heights, defined as those that produce the closest agreement with the ground-based reference networks. Derived using the first year of observations from GOES-East position, the optimal emitter height varies geographically and seasonally in a manner consistent with known meteorological regimes. Application of the optimal emitter height approximately doubles the fraction of area near the limb for which peak location errors are less than half a GLM pixel.
A Parameter for Quantifying the Macroscale Asymmetry of Tropical Cyclone Cloud Clusters
Authors: Ng Kelvin Sai-cheong , Lee Man Hoi , Zong Yongqiang
Published: August 2020

A parameter to quantify macroscale (i.e., systemwide) asymmetry of tropical cyclones (TC) in infrared satellite images, galaxy asymmetry (GASYM), which is adopted from astronomy, is described. In addition, an alternative approach to identify TC cloud clusters that is based on a density-based spatial clustering algorithm, cluster identification (CI), is presented in this study. Although a commonly used approach in TC study, the predefined radius of calculation (ROC), can be used to identify the TC region in the calculation of GASYM, this approach is not optimal because the size of the TC cloud cluster is often unknown in the calculation. The area specified by the ROC often includes pixels that do not belong to the TC cloud cluster and excludes pixels that belong to the TC cloud cluster. The CI approach addresses this issue by identifying TC cloud clusters of any size with any shape, because it depends solely on the threshold brightness temperature that corresponds to the upper bound of the brightness temperature of the specific cloud types. This study shows that the CI approach can be integrated into the GASYM calculation as an objective measure of TC symmetry. Although GASYM-CI and intensity are correlated, the relationship between GASYM-CI and intensity depends on the size of the TC cloud cluster. Comparison between GASYM and an existing objective method to quantify symmetry of TCs, the deviation angle variance technique, is also presented.
Updates on the Radar Data Quality Control in the MRMS Quantitative Precipitation Estimation System
Authors: Tang Lin , Zhang Jian , Simpson Micheal , Arthur Ami , Grams Heather , Wang Yadong , Langston Carrie
Published: August 2020

The Multi-Radar-Multi-Sensor (MRMS) system was transitioned into operations at the National Centers for Environmental Prediction in the fall of 2014. It provides high-quality and high-resolution severe weather and precipitation products for meteorology, hydrology, and aviation applications. Among processing modules, the radar data quality control (QC) plays a critical role in effectively identifying and removing various nonhydrometeor radar echoes for accurate quantitative precipitation estimation (QPE). Since its initial implementation in 2014, the radar QC has undergone continuous refinements and enhancements to ensure its robust performance across seasons and all regions in the continental United States and southern Canada. These updates include 1) improved melting-layer delineation, 2) clearance of wind farm contamination, 3) mitigation of corrupt data impacts due to hardware issues, 4) mitigation of sun spikes, and 5) mitigation of residual ground/lake/sea clutter due to sidelobe effects and anomalous propagation. This paper provides an overview of the MRMS radar data QC enhancements since 2014.
Mechanism of Cloud Droplet Motion under Sound Wave Actions
Authors: Li Fang-Fang , Jia Ying-Hui , Wang Guang-Qian , Qiu Jun
Published: August 2020

Sound waves have proven to be effective in promoting the interaction and aggregation of droplets. It is necessary to theoretically study the motion of particles in a sound field to develop new acoustic technology for precipitation enhancement. In this paper, the motion of cloud droplets due to a traveling sound wave field emitted from the ground to the air is simulated using the motion equation of point particles. The force condition of the particles in the oscillating flow field is analyzed. Meanwhile, the effects of droplet size, sound frequency, and sound pressure level (SPL) on the velocity and displacement of the droplets are also investigated. The results show that Stokes force and gravity play a dominant role in the falling process of cloud droplets, and the effect of the sound wave is mainly reflected in the fluctuation of velocity and displacement, which also promotes the displacement of cloud droplets to a certain extent. The maximum displacement increments of cloud droplets of 10 µm can reach 9200 µm due to the action of sound waves of 50 Hz and 143.4 dB. The SPL required for a noticeable velocity fluctuation for droplets of 10 µm with frequency of 50 Hz is 88.2 dB. When SPL < 100 dB and frequency > 500 Hz, the effect is negligible. The cloud droplet size plays a significant role in the motion, and the sound action is weaker for larger particles. For a smaller sound frequency and higher SPL, the effect of the sound wave is more prominent.
Dynamic Mapping of Along-Track Ocean Altimetry: Performance from Real Observations
Authors: Ballarotta Maxime , Ubelmann Clément , Rogé Marine , Fournier Florent , Faugère Yannice , Dibarboure Gérald , Morrow Rosemary , Picot Nicolat
Published: August 2020

The dynamic optimal interpolation (DOI) method merges altimetric sea surface height (SSH) data into maps that are continuous in time and space. Unlike the traditional linear optimal interpolation (LOI) method, DOI has the advantage of considering a nonlinear temporal propagation of the SSH field. DOI has been successfully applied to along-track pseudo-observations in observing system simulation experiments (OSSEs), demonstrating a reduction in interpolation error in highly turbulent regions compared to LOI mapping. In the present study, we further extend the validation of the DOI method by an observing system experiment (OSE). We applied and validated the DOI approach with real nadir-altimetric observations in four regional configurations. Overall, the qualitative and quantitative assessments of these realistic SSH maps confirm the higher level of performance of the DOI approach in turbulent regions. It is more of a challenge to outperform the conventional LOI mapping in coastal and low-energy regions. Validations against LOI maps distributed by the Copernicus Marine Environment Monitoring Service indicate a 10%–15% increase in average performance and an improved resolution limit toward shorter wavelengths. The DOI method also shows improved mesoscale mapping of intense jets and fronts and reveals new eddies with smoother trajectories.
Analysis of Back-Building Convection in Simulations with a Strong Low-Level Stable Layer
Authors: Hitchcock Stacey M. , Schumacher Russ S.
Published: August 2020

In a mesoscale convective system (MCS), convection that redevelops over (i.e., back-builds), and/or repeatedly passes over (i.e., trains) a region for an extended period of time can contribute to extreme rainfall and flash flooding. Past studies have indicated that both mesoscale ascent and lifting of the inflow layer by a cold pool or bore are important when this back-building/training convection is displaced from the leading line [sometimes called rearward off-boundary development (ROD)]. However, Plains Elevated Convection At Night (PECAN) field campaign observations suggest that the stability of the nocturnal boundary layer is highly variable and some MCSs with ROD have only a weak surface cold pool. Numerical simulations presented in this study suggest that in an environment with strong boundary layer stability, ROD can be supported by mechanisms other than those mentioned above. Simulations were initialized using a sounding from ahead of a PECAN MCS with a strong stable layer and ROD, and the three-dimensional simulation produced an MCS similar to that observed despite the homogeneous initial conditions. Some of the findings presented herein challenge existing understanding of nocturnal MCSs, and especially how downdrafts interact with a stable boundary layer. Notably, downdrafts can reach the surface, and different regions of the MCS may have different propagation mechanisms and different relevant inflow layers. Unlike previous studies of ROD, parcel lifting may be supported by an intrusion (an elevated layer of downdraft air) modified by the three-dimensional vertical wind shear.
Heavy Rainfall Events over Central Oahu under Weak Wind Conditions during Seasonal Transitions
Authors: Hsiao Feng , Chen Yi-Leng , Hitzl David Eugene
Published: August 2020

Short-lived afternoon heavy rainfall events may form over central Oahu during seasonal transition periods (June and October) under favorable large-scale settings. These include a deep moist layer with relatively high precipitable water (>40 mm), blocking pattern in midlatitudes with a northeast–southwest moist tongue from low latitudes ahead of an upper-level trough, absence of a trade wind inversion, and weak (<3 m s−1) low-level winds. Our high-resolution (1.5 km) model results show that immediately before the storm initiation, daytime land surface heating deepens the mixed layer over central Oahu and the top of the mixed layer reaches the lifting condensation level. Meanwhile, the development of onshore/sea-breeze flows, driven by land–sea thermal contrast, brings in moist maritime air over the island interior. Finally, convergence of onshore flows over central Oahu provides the localized lifting required for the release of instability. Based on synoptic and observational analyses, nowcasting with a lead time of 2–3 h ahead of this type of event is possible. In the absence of orographic effects after removing model topography, processes that lead to heavy rainfall are largely unchanged, and subsequent development of heavy showers over central Oahu are still simulated. However, when surface heat and moisture fluxes are turned off, convective cells are not simulated in the area. These results indicate that daytime heating is crucial for the development of this type of heavy rainfall event under favorable large-scale settings.
Impact of Assimilating Future Clear-Air Radial Velocity Observations from Phased-Array Radar on a Supercell Thunderstorm Forecast: An Observing System Simulation Experiment Study
Authors: Huang Yongjie , Wang Xuguang , Kerr Christopher , Mahre Andrew , Yu Tian-You , Bodine David
Published: August 2020

Phased-array radar (PAR) technology offers the flexibility of sampling the storm and clear-air regions with different update times. As such, the radial velocity from clear-air regions, typically with a lower signal-to-noise ratio, can be measured more accurately. In this work, observing system simulation experiments are conducted to explore the potential value of assimilating clear-air radial velocity observations to improve numerical prediction of supercell thunderstorms. Synthetic PAR observations of a splitting supercell are assimilated at different life cycle stages using an ensemble Kalman filter. Results show that assimilating environmental clear-air radial velocity can reduce wind errors in the near-storm environment and within the precipitation region. Improvements in the forecast are seen at different stages, especially for the forecast after 30 min. After assimilating clear-air radial velocity observations, the probabilities of updraft helicity and precipitation within the corresponding swaths of the truth simulation increase up to 30%–40%. Additional diagnostics suggest that the more accurate track forecast, stronger vertical motion, and better-maintained supercell can be attributed to the better analysis and prediction of the mean environmental winds and linear and nonlinear dynamic forces. Consequently, assimilating clear-air radial velocity produces accurate storm structure (rotating updrafts), updraft size, and storm track, and improves the surface accumulated precipitation forecast. The performance of forecasts with a higher frequency of assimilating clear-air radial velocity does not show systematic improvement. These results highlight the potential of assimilating clear-air radial velocity observations to improve numerical weather prediction forecasts of supercell thunderstorms.