bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuzuê
Authors: Moreira Carina Maria Guimarães , Dias Rayla
Published: August 2020

O artigo apresenta reflexões a respeito das noções de tragédia e trágico a partir das ideias de Peter Szondi em Ensaio sobre o trágico e Raymond Williams em Tragédia moderna, dialogando com as concepções de teatro político de Erwin Piscator e de teatro épico de Bertolt Brecht, bases teóricas da pesquisa artística desenvolvida no Núcleo de Estudos em Teatro Político do Grupo de Pesquisa em História, Política e Cena- Netep/GPHPC/UFSJ. No campo teórico, refletiremos sobre o modo como as dimensões da tragédia e do trágico atuam no campo político da cena, a partir dos modelos citados e de análise de um experimento contemporâneo. Por fim, à luz do conjunto teórico, analisamos o experimento cênico Fuzuê, resultado de pesquisa desenvolvida entre 2015 e 2017, buscando identificar como a dimensão histórica e trágica da exploração social foi ali debatida.
Sobre Stabat Mater
Authors: Toledo Paulo Bio
Published: August 2020

O artigo é um exercício crítico sobre o espetáculo Stabat Mater, criado por Janaína Leite e uma equipe de colaboradoras, em 2019. A montagem se transformou, muito rapidamente, em uma espécie de marco teatral na cidade de São Paulo. Postulados como a “emergência do real”, a implicação da própria artista na substância da obra, mais a busca de uma zona de limiar, na qual se tensionasse a fronteira entre arte e vida, causam espanto e fascínio, porém é provável que também apresentem, como contraface, doses elevadas de idealismo e mistificação. São formulações estéticas fascinantes que reorientam a noção de política nas artes desde os anos 1970, ao mesmo tempo parecem acompanhar e reproduzir novos padrões de consumo cultural e trabalho atomizado vigentes no capitalismo contemporâneo. Em síntese, aquilo que por um lado aparece como transgressão e recusa da desordem do mundo, por outro apresenta um aspecto de realinhamento, adesão e fascínio pela barbárie.
Teatros documentários
Authors: Pupo Maria Lúcia de Souza Barros
Published: August 2020

O artigo apresenta o livro Les Théâtres Documentaires, de Béatrice Picon-Vallin e Érica Magris, destacando a amplitude e a relevância da obra.
Maria Alice Vergueiro: a acadêmica
Authors: Koudela Ingrid Dormien
Published: August 2020

Homenagem a Maria Alice Vergueiro e a seu legado.
A experimentação política
Authors: Neveux Olivier
Published: August 2020

Paru in M. Losco-Léna (sous la direction de), Faire théâtre sous le signe de la recherche, postface de M. Corvin, Presses Universitaires de Rennes (« Le Spectaculaire »), 2017, pp. 293-303.
Conceito constitucional dos Serviços Sociais Autônomos
Authors: Almeida Edvaldo Nilo de
Published: August 2020

O objeto de estudo são os serviços sociais autônomos e o conceito constitucional fundado no art. 6° da Constituição Federal de 1988. Por certo, a delimitação do estudo são os serviços sociais autônomos, especificadamente o seu conceito constitucional. Com esse propósito, busca-se responder se o fenômeno da criação e atuação dos serviços sociais conflita com a Constituição Federal de 1988.
As audiências de conciliação e mediação nos conflitos envolvendo a Fazenda Pública
Authors: Garcel Adriane Da Silva , Fogaça Anderson Ricardo , Souza Netto José Laurindo De
Published: August 2020

O presente artigo tem como finalidade abordar as novas diretrizes processuais e procedimentais elencadas no Código de Processo Civil de 2015, a fim de salvaguardar a efetiva solução do mérito da demanda sem lesar os princípios da celeridade e eficiência processual. Assim, pode-se citar o sistema multiportas, o qual inclui diversos instrumentos para solução de conflitos. Entre estes, estão a audiência de conciliação ou mediação, a ser realizada em momento anterior à apresentação da contestação, conforme art. 334 do CPC. Nessa perspectiva, a Fazenda Pública não foi repelida desse procedimento, apesar de seus interesses serem, via de regra, indisponíveis. Nesse sentido, “as Fazendas Públicas devem dar publicidade às hipóteses em que seus órgãos de Advocacia Pública estão autorizados a aceitar autocomposição”. Entretanto, o legislador não elencou nenhuma especificidade para a audiência de conciliação ou mediação quando o ente público for sujeito processual. Nesse caso, frisa-se que, em decorrência do princípio da legalidade, o administrador público só poderá transacionar se houver previsão legislativa para tal. Contudo, conforme previsto no artigo 3º, § 3º, do CPC/2015, cabe aos advogados o estímulo aos meios de autocomposição, como também informar ao juízo caso sobrevenha autorização para transação, como forma de obedecer ao artigo supracitado.
O regime jurídico das empresas estatais no Brasil e seu papel na promoção do desenvolvimento nacional
Authors: Vilela Danilo Vieira , Bonito Bruna Cabrera de
Published: August 2020

O presente artigo busca discutir o regime jurídico e o papel das empresas estatais no Brasil. Para tanto, parte-se de uma análise do modelo de intervenção do Estado brasileiro na ordem econômica para, a seguir, abordar os principais aspectos da disciplina jurídica das estatais, conforme a Lei nº 13.303/2016. Posteriormente, busca-se compreender o perfil das estatais no Brasil hoje, tomando-se como ponto de partida a evolução histórica dessas entidades no cenário econômico-administrativo brasileiro. Metodologicamente, utiliza-se de uma pesquisa dedutiva para, ao final, demonstrar a relevância das empresas estatais como instrumentos da intervenção do Estado na economia, aptos a promover a retomada do desenvolvimento nacional.
Extinção da relação jurídica criada por ato administrativo válido e concreto sob a ótica do direito dos administrados
Authors: Paschoa André Paulani
Published: August 2020

Estudo teórico que aborda as relações jurídicas formadas entre Administração Pública e administrado decorrentes de atos administrativos concretos. Cada um dos meios de extinção da relação jurídica é discutido para compreender qual é o impacto aos direitos dos administrados na dissolução da relação jurídica. As reflexões necessariamente passam a tratar sobre a necessidade de ser desconstituída a relação jurídica pelo Estado. Caminha-se no sentido de aproximar conceitos que doutrinariamente são tratados como apartados, especialmente os de retirada de ato administrativo por meio de derrubada/contraposição e de retirada de ato administrativo por meio de decaimento/caducidade. Por força da presunção de legitimidade dos atos administrativos, propõe-se uma solução teórica que aproxime os dois conceitos doutrinários para compreender o fenômeno jurídico estudado. Por fim, com base nessa proposição, afirma-se que os direitos adquiridos pelos administrados não podem ser afetados por norma legal posteriormente emitida.
A extinção de conselhos e fóruns participativos pelo Decreto n. 9.759/19
Authors: Oliveira Gustavo Justino de
Published: August 2020

No atual contexto político institucional do Brasil, a proeminência do espaço virtual como via principal de participação popular, aliada às desenfreadas fake news que tomam conta das mídias sociais, gera apreensão, considerando-se o paralelo enfraquecimento dos efetivos instrumentos de participação popular, tal como pode ser observado na veiculação de notícias envolvendo possível extinção dos Conselhos Participativos de Ministérios. A novidadeira realidade em que a política e sociedade brasileiras se encontra submergida traz consigo preocupações quanto à manutenção e aprimoramento do Estado Democrático de Direito, postas as incertezas e riscos das mídias e redes sociais como a nova “ágora”, bem como a confusão dos conteúdos postados em tais locais com a opinião pública. Diante da presente problemática, buscar-se-á no presente trabalho compreender e investigar as relações entre a participação popular e democracia na atualidade brasileira, propondo possíveis soluções para que a frágil situação ainda em estágio inicial não progrida para ameaças ao Estado Democrático de Direito, acarretadas por suposta atrofia da participação popular no âmbito político.
Exposure to Particulate Matter Is Associated With Elevated Blood Pressure and Incident Hypertension in Urban India
Authors: Prabhakaran Dorairaj , Mandal Siddhartha , Krishna Bhargav , Magsumbol Melina , Singh Kalpana , Tandon Nikhil , Venkat Narayan K.M. , Shivashankar Roopa , Kondal Dimple , Ali Mohammed K. , Srinath Reddy Kolli , Schwartz Joel D. ,   GeoHealth Hub Study investigators, COE-CARRS Study investigators
Published: August 2020

Ambient air pollution, specifically particulate matter of diameter <2.5 μm, is reportedly associated with cardiovascular disease risk. However, evidence linking particulate matter of diameter <2.5 μm and blood pressure (BP) is largely from cross-sectional studies and from settings with lower concentrations of particulate matter of diameter <2.5 μm, with exposures not accounting for myriad time-varying and other factors such as built environment. This study aimed to study the association between long- and short-term ambient particulate matter of diameter <2.5 μm exposure from a hybrid spatiotemporal model at 1-km×1-km spatial resolution with longitudinally measured systolic and diastolic BP and incident hypertension in 5342 participants from urban Delhi, India, within an ongoing representative urban adult cohort study. Median annual and monthly exposure at baseline was 92.1 μg/m
3
(interquartile range, 87.6–95.7) and 82.4 μg/m
3
(interquartile range, 68.4–107.0), respectively. We observed higher average systolic BP (1.77 mm Hg [95% CI, 0.97–2.56] and 3.33 mm Hg [95% CI, 1.12–5.52]) per interquartile range differences in monthly and annual exposures, respectively, after adjusting for covariates. Additionally, interquartile range differences in long-term exposures of 1, 1.5, and 2 years increased the risk of incident hypertension by 1.53× (95% CI, 1.19–1.96), 1.59× (95% CI, 1.31–1.92), and 1.16× (95% CI, 0.95–1.43), respectively. Observed effects were larger in individuals with higher waist-hip ratios. Our data strongly support a temporal association between high levels of ambient air pollution, higher systolic BP, and incident hypertension. Given that high BP is an important risk factor of cardiovascular disease, reducing ambient air pollution is likely to have meaningful clinical and public health benefits.
Difficult and failed intubation in Caesarean general anaesthesia: a four-year retrospective review
Authors: Lee YL , Lim ML , Leong WL , Lew E
Published: August 2020

INTRODUCTION General anaesthesia is associated with higher maternal morbidity and mortality when compared with regional anaesthesia, related mainly to failure of intubation, hypoxia and aspiration. The aim of this retrospective review was to define the incidence of failed and difficult intubation in parturients undergoing general anaesthesia for Caesarean delivery at a high-volume obstetric hospital in Singapore. METHODS All parturients who underwent Caesarean delivery under general anaesthesia from 2013 to 2016 were identified and their medical records were reviewed to extract pertinent data. Difficult intubation was defined as ‘requiring more than one attempt at intubation or documented as such, based on the opinion of the anaesthetist’. A failed intubation was defined as ‘inability to intubate the trachea, with subsequent abandonment of intubation as a means of airway management’. RESULTS Records of 660 Caesarean sections under general anaesthesia were extracted. The mean age of the parturients was 32.1 ± 5.5 years and the median body mass index was 27.5 (interquartile range 24.6–31.1) kg/m2. Rapid sequence induction with cricoid pressure was employed for all patients, with thiopentone and succinylcholine being administered for 91.2% and 98.1% of patients, respectively. There were 33 difficult intubations among 660 patients, yielding an incidence of 5.0%. Junior trainees performed about 90% of all intubations and 28 (84.8%) out of 33 difficult intubations. Repeat intubations were performed by senior residents/fellows (57.1%) and consultants (14.3%). No instance of failed intubation was reported. CONCLUSION The local incidence of difficult obstetric intubation was one in 20. No failure of intubation was observed.
Spatiotemporal Variability of Precipitation and Its Statistical Relations to ENSO in the High Andean Rio Bogotá Watershed, Colombia
Authors: Anselm Norbert , Rojas Oscar , Brokamp Grischa , Schütt Brigitta
Published: August 2020

Sustainable management of biodiversity requires a thorough understanding of local climate and weather, particularly in areas where ecosystems have been degraded and where life is highly adapted to or dependent on narrow ecological niches. Furthermore, society, economy, and culture of urban agglomerations are directly affected by the quality and quantity of services provided by adjacent ecosystems, which makes knowledge of regional characteristics and impact of climate variability crucial. Here, we present precipitation data from six meteorological stations spread across several orographic zones of the eastern Andes in the surroundings of Bogotá, Colombia’s biggest urban agglomeration. The time series of rainfall data are analyzed statistically, examined regarding the occurrence of cyclicity in relation to ENSO, and correlated to the multivariate El Niño–Southern Oscillation index (MEI). Results offer no conclusive ENSO-related cycles but show that data of most of the stations are marked by annual or semestral cyclicity. There is no straightforward correlation between MEI and monthly precipitation values, and neither filtered nor lagged values showed any conclusive and significant correlation. Stations within the same orographic zones do not necessarily bring forth comparable statistical results. Temporal and spatial properties of precipitation appear to result from micro- and mesoscale topoclimates rather than from ENSO variability.
Evaluation of Orographic Cloud Seeding Using a Bin Microphysics Scheme: Three-Dimensional Simulation of Real Cases
Authors: Geresdi István , Xue Lulin , Sarkadi Noémi , Rasmussen Roy
Published: August 2020

The University of Pécs and NCAR Bin (UPNB) microphysical scheme was implemented into the mesoscale Weather Research and Forecast (WRF) Model that was used to study the impact of silver iodide (AgI) seeding on precipitation formation in winter orographic clouds. Four different experimental units were chosen from the Wyoming Weather Modification Pilot Project to simulate the seeding effect. The results of the numerical experiments show the following: (i) Comparisons with the soundings, snow gauges, and microwave radiometer data indicate that the three-dimensional simulations with detailed microphysics reasonably represent both the dynamics and the microphysics of real clouds. (ii) The dispersion of the AgI particles from the simulated ground-based seeding was effective because of turbulent mixing. (iii) In the investigated cases (surface temperature is less than 0°C), surface precipitation and precipitation efficiency show low susceptibility to the concentrations of cloud condensation nuclei and natural ice nucleating particles. (iv) If the available liquid water content promotes the enhancement of the number of snowflakes by diffusional growth, the surface precipitation can be increased by more than 5%. A novel parameter relevant to orographic clouds, horizontally integrated liquid water path (LWP), was evaluated to find the relation between seeding efficiency and liquid water content. The impact of seeding is negligible if the horizontal LWP is less than 0.1 mm and is apparent if the horizontal LWP is larger than 1 mm, as based on the cases investigated in this study.
A Comparison of Low-Cost Collector Configurations for Quantifying Ice Accretion
Authors: Campbell John L. , Rustad Lindsey E. , Garlick Sarah , Newman Noah , Stanovick John S. , Halm Ian , Driscoll Charles T. , Barjenbruch Brian L. , Burakowski Elizabeth , Hilberg Steven D. , Sanders Kristopher J. , Shafer Jason C. , Doesken Nolan J.
Published: August 2020

Ice storms are important winter weather events that can have substantial environmental, economic, and social impacts. Mapping and assessment of damage after these events could be improved by making ice accretion measurements at a greater number of sites than is currently available. There is a need for low-cost collectors that can be distributed broadly in volunteer observation networks; however, use of low-cost collectors necessitates understanding of how collector characteristics and configurations influence measurements of ice accretion. A study was conducted at the Hubbard Brook Experimental Forest in New Hampshire that involved spraying water over passive ice collectors during freezing conditions to simulate ice storms of different intensity. The collectors consisted of plates composed of four different materials and installed horizontally; two different types of wires strung horizontally; and rods of three different materials, with three different diameters, and installed at three different inclinations. Results showed that planar ice thickness on plates was 2.5–3 times as great as the radial ice thickness on rods or wires, which is consistent with expectations based on theory and empirical evidence from previous studies. Rods mounted on an angle rather than horizontally reduced the formation of icicles and enabled more consistent measurements. Results such as these provide much needed information for comparing ice accretion data. Understanding of relationships among collector configurations could be refined further by collecting data from natural ice storms under a broader range of weather conditions.
Differential Credibility Assessment for Statistical Downscaling
Authors: Pryor S. C. , Schoof J. T.
Published: August 2020

Climate science is increasingly using (i) ensembles of climate projections from multiple models derived using different assumptions and/or scenarios and (ii) process-oriented diagnostics of model fidelity. Efforts to assign differential credibility to projections and/or models are also rapidly advancing. A framework to quantify and depict the credibility of statistically downscaled model output is presented and demonstrated. The approach employs transfer functions in the form of robust and resilient generalized linear models applied to downscale daily minimum and maximum temperature anomalies at 10 locations using predictors drawn from ERA-Interim reanalysis and two global climate models (GCM; GFDL-ESM2M and MPI-ESM-LR). The downscaled time series are used to derive several impact-relevant Climate Extreme (CLIMDEX) temperature indices that are assigned credibility based on 1) the reproduction of relevant large-scale predictors by the GCMs (i.e., fraction of regression beta weights derived from predictors that are well reproduced) and 2) the degree of variance in the observations reproduced in the downscaled series following application of a new variance inflation technique. Credibility of the downscaled predictands varies across locations and between the two GCM and is generally higher for minimum temperature than for maximum temperature. The differential credibility assessment framework demonstrated here is easy to use and flexible. It can be applied as is to inform decision-makers about projection confidence and/or can be extended to include other components of the transfer functions, and/or used to weight members of a statistically downscaled ensemble.
Simulation of Flow Fields in Complex Terrain with WRF-LES: Sensitivity Assessment of Different PBL Treatments
Authors: Liu Yujue , Liu Yubao , Muñoz-Esparza Domingo , Hu Fei , Yan Chao , Miao Shiguang
Published: August 2020

A multiscale modeling study of a real case has been conducted to explore the capability of the large-eddy simulation version of the Weather Research and Forecasting Model (WRF-LES) over Xiaohaituo Mountain (a game zone for the Beijing, China, 2022 Winter Olympic Games). In comparing WRF-LES results with observations collected during the Mountain Terrain Atmospheric Observations and Modeling (MOUNTAOM) field campaign, it is found that at 37-m resolution with LES settings, the model can reasonably capture both large-scale events and microscale atmospheric circulation characteristics. Employing the Shuttle Radar Topography Mission 1 arc s dataset (SRTM1; ~30 m) high-resolution topographic dataset instead of the traditional USGS_30s (~900 m) dataset effectively improves the model capability for reproducing fluctuations and turbulent features of surface winds. Five sensitivity experiments are conducted to investigate the impact of different PBL treatments, including YSU/Shin and Hong (SH) PBL schemes and LES with 1.5-order turbulence kinetic energy closure model (1.5TKE), Smagorinsky (SMAG), and nonlinear backscatter and anisotropy (NBA) subgrid-scale (SGS) stress models. In this case, at gray-zone scales, differences between YSU and SH are negligible. LES outperform two PBL schemes that generate smaller turbulence kinetic energy and increase the model errors for mean wind speed, energy spectra, and probability density functions of velocity. Another key finding is that wind field features in the boundary layer over complex terrain are more sensitive to the choice of SGS models than above the boundary layer. With the increase of model resolution, the effects of the SGS model become more significant, especially for the statistical characteristics of turbulence. Among these three SGS models, NBA has the best performance. Overall, this study demonstrates that WRF-LES is a promising tool for simulating real weather flows over complex terrain.
Diurnal Black-Sky Surface Albedo Parameterization of Snow
Authors: Manninen Terhikki , Jääskeläinen Emmihenna , Riihelä Aku
Published: August 2020

Surface albedo, the fraction of incoming solar radiation reflected hemispherically by the surface, is an essential climate variable (ECV) directly related to the energy budget of Earth. The presence and properties of snow cover alter surface albedo significantly, with variability in temporal scales reaching from seasonal to diurnal. The diurnal variation of snow albedo is typically parameterized with the solar zenith angle, but it cannot take into account asymmetry with respect to midday. Using the solar azimuth angle instead is suggested, since especially in the melting season the snow albedo varies highly asymmetrically during the day. To derive a general time- and latitude-independent formula, the azimuth angle values are normalized. Baseline Surface Radiation Network data are used to derive an empirical formula for the diurnal variation of snow black-sky surface albedo. The overall accuracy is on the order of 0.02, and the relative accuracy is about 3%.
Ensemble Sensitivity Analysis of Tropical Cyclone Intensification Rate during the Development Stage
Authors: Hu Chih-Chi , Wu Chun-Chieh
Published: August 2020

Ensemble sensitivity analysis based on convective-permitting ensemble simulations is used to understand the processes associated with tropical cyclone (TC) intensification under idealized conditions. Partial correlations between different variables and the future TC intensification rate, with the effect of intensity removed, are used to identify the sensitive factors. It is found that the equivalent potential temperature (θe) in the region from the radius of maximum wind (RMW) to 3 times the RMW below 2 km (hereafter, the sensitive region) has the largest correlation (over 0.7) with 2.5-h intensity change. It is found that higherθein the sensitive region is associated with not only a stronger updraft but also an inward shift of vertical motion in the mid- to upper eyewall. This suggests that higherθejust outside the RMW is favorable to TC intensification not only because of the larger amount of the heating, but also due to the heating location that is closer to the center. Trajectory analysis shows that the parcels in the sensitive region are mainly from the boundary layer inflow and the midlevel inflow. It is found that when the outer rainband is active, the midlevel inflow becomes stronger and is able to bring more low-θeair into the boundary layer, and theθeradially inward to the rainband decreases. Verification experiments justify that higherθearound the RMW to 3 times the RMW is favorable to TC intensification, while higherθeaway from 5 times the RMW is shown to be unfavorable for TC intensification.
Cloud-Top Entrainment in Mixed-Phase Stratocumulus and Its Process-Level Representation in Large-Eddy Simulation
Authors: Rauterkus Robert , Ansorge Cedrick
Published: August 2020

Cloud-top entrainment is a crucial process for the evolution of stratocumulus and is driven by interactions of radiation, microphysics, and turbulence on scales reaching down to less than one meter. Regardless of this fact, most large-eddy simulation studies still apply a horizontal resolution of tens of meters, not resolving these interactions sufficiently. Here, based on an extensive observational campaign, we define a weak-shear benchmark scenario for large-eddy simulation over Arctic ice and for the first time perform large-eddy simulation of mixed-phase stratocumulus with horizontal resolutions of 35, 10, and 3.5 m. Thereby, we investigate the processes contributing to cloud-top entrainment and their role for the evolution of stratocumulus with a particular focus on resolution sensitivity. First, we find that a horizontal grid spacing larger than 10 m insufficiently represents the effects of small-scale microphysical cooling and turbulent engulfment on cloud-top entrainment. Indeed, the small size of energy-containing eddies—a consequence of the intense stratification in the vicinity of the cloud-top region—violates the underlying assumptions of subgridscale models by buoyant suppression of eddies at the large-eddy simulation filter scale. Second, the decrease in cloud-top entrainment due to these insufficiently represented processes results in 15% less cloud water after 6 h of simulation and a corresponding optical thinning of the cloud. Third, we show that the applied nonequilibrium microphysics cause microphysical heating beneath the cloud top, which partly counteracts the evaporative cooling.
Evaluations of the Thermodynamic Phases of Clouds in a Cloud-System-Resolving Model Using CALIPSO and a Satellite Simulator over the Southern Ocean
Authors: Roh Woosub , Satoh Masaki , Hashino Tempei , Okamoto Hajime , Seiki Tatsuya
Published: August 2020

A new evaluation method for the thermodynamic phases of clouds in cloud-system-resolving models is presented using CALIPSO observations and a satellite simulator. This method determines the thermodynamic phases using the depolarization ratio and a cloud extinction proxy. For the evaluation, we introduced empirical parameterization of the depolarization ratio of ice and water clouds using temperatures of a reanalysis dataset and total attenuated backscatters of CALIPSO. We evaluated the mixed-phase clouds simulated in a cloud-system-resolving model over the Southern Ocean using single-moment and double-moment bulk cloud microphysics schemes, referred to as NSW6 and NDW6, respectively. The NDW6 simulations reproduce supercooled water clouds near the boundary layer that are consistent with the observations. Conversely, the NSW6 simulations failed to reproduce such supercooled water clouds. Consistencies between the cloud classes diagnosed by the evaluation method and the simulated hydrometeor categories were examined. NDW6 shows diagnosed water and ice classes that are consistent with the simulated categories, whereas the ice category simulated with NSW6 is diagnosed as liquid water by the present method due to the large extinction from the ice cloud layers. Additional analyses indicated that ice clouds with a small effective radius and large ice water content in NSW6 lead to erroneous values for the fraction of the diagnosed liquid water. It is shown that the uncertainty in the cloud classification method depends on the details of the cloud microphysics schemes. It is important to understand the causes of inconsistencies in order to properly understand the cloud classification applied to model evaluations as well as retrievals.
A Businger Mechanism for Intermittent Bursting in the Stable Boundary Layer
Authors: van der Linden Steven J. A. , van de Wiel Bas J. H. , Petenko Igor , van Heerwaarden Chiel C. , Baas Peter , Jonker Harmen J. J.
Published: August 2020

High-resolution large-eddy simulations of the Antarctic very stable boundary layer reveal a mechanism for systematic and periodic intermittent bursting. A nonbursting state with a boundary layer height of just 3 m is alternated by a bursting state with a height of ≈5 m. The bursts result from unstable wave growth triggered by a shear-generated Kelvin–Helmholtz instability, as confirmed by linear stability analysis. The shear at the top of the boundary layer is built up by two processes. The upper, quasi-laminar layer accelerates due to the combined effect of the pressure force and rotation by the Coriolis force, while the lower layer decelerates by turbulent friction. During the burst, this shear is eroded and the initial cause of the instability is removed. Subsequently, the interfacial shear builds up again, causing the entire sequence to repeat itself with a time scale of ≈10 min. Despite the clear intermittent bursting, the overall change of the mean wind profile is remarkably small during the cycle. This enables such a fast erosion and recovery of the shear. This mechanism for cyclic bursting is remarkably similar to the mechanism hypothesized by Businger in 1973, with one key difference. Whereas Businger proposes that the flow acceleration in the upper layer results from downward turbulent transfer of high-momentum flow, the current results indicate no turbulent activity in the upper layer, hence requiring another source of momentum. Finally, it would be interesting to construct a climatology of shear-generated intermittency in relation to large-scale conditions to assess the generality of this Businger mechanism.
Understanding How Complex Terrain Impacts Tornado Dynamics Using a Suite of High-Resolution Numerical Simulations
Authors: Satrio Martin A. , Bodine David J. , Reinhart Anthony E. , Maruyama Takashi , Lombardo Franklin T.
Published: August 2020

A simulated vortex within a large-eddy simulation is subjected to various surface terrain, implemented through the immersed boundary method, to analyze the effects of complex topography on vortex behavior. Thirty simulations, including a control with zero-height terrain, are grouped into four categories—2D sinusoidal hills, 3D hills, valleys, and ridges—with slight modifications within each category. A medium-swirl-ratio vortex is translated over shallow terrain, which is modest in size relative to the vortex core diameter and with no explicitly defined surface roughness. While domain size restricts results to the very near-field effects of terrain, vortex–terrain interaction yields notable results. Terrain influences act to increase the variability of the near-surface vortex, including a notable leftward (rightward) deflection, acceleration (deceleration), and an expansion (a contraction) of the vortex as it ascends (descends) the terrain owing to changes in the corner flow swirl ratio. Additionally, 10-m track analyses show stronger horizontal wind speeds are found 1) on upslope terrain, resulting from transient subvortices that are more intense compared to the control simulation, and 2) in between adjacent hills simultaneous with strong pressure perturbations that descend from aloft. Composite statistics confirm that the region in between adjacent hills has the strongest horizontal wind speeds, while upward motions are more intense during ascent. Overall, valley (ridge) simulations have the largest horizontal (vertically upward) wind speeds. Last, horizontal and vertical wind speeds are shown to be affected by other terrain properties such as slope steepness and two-dimensionality of the terrain.
The Strong Impact of Weak Horizontal Convergence on Continental Shallow Convection
Authors: Kurowski Marcin J. , Grabowski Wojciech W. , Suselj Kay , Teixeira João
Published: August 2020

Idealized large-eddy simulation (LES) is a basic tool for studying three-dimensional turbulence in the planetary boundary layer. LES is capable of providing benchmark solutions for parameterization development efforts. However, real small-scale atmospheric flows develop in heterogeneous and transient environments with locally varying vertical motions inherent to open multiscale interactive dynamical systems. These variations are often too subtle to detect them by state-of-the-art remote and in situ measurements, and are typically excluded from idealized simulations. The present study addresses the impact of weak [i.e., O(10−6) s−1] short-lived low-level large-scale convergence/divergence perturbations on continental shallow convection. The results show a strong response of shallow nonprecipitating convection to the applied weak large-scale dynamical forcing. Evolutions of CAPE, mean liquid water path, and cloud-top heights are significantly affected by the imposed convergence/divergence. In contrast, evolving cloud-base properties, such as the area coverage and mass flux, are only weakly affected. To contrast those impacts with microphysical sensitivity, the baseline simulations are perturbed assuming different observationally based cloud droplet number concentrations and thus different rainfall. For the tested range of microphysical perturbations, the imposed convergence/divergence provides significantly larger impact than changes in the cloud microphysics. Simulation results presented here provide a stringent test for convection parameterizations, especially important for large-scale models progressing toward resolving some nonhydrostatic effects.
Role of Gravity Waves in a Vortex-Split Sudden Stratospheric Warming in January 2009
Authors: Song Byeong-Gwon , Chun Hye-Yeong , Song In-Sun
Published: August 2020

The role of gravity waves (GWs) in a sudden stratospheric warming (SSW) event that occurred in January 2009 (SSW09) is investigated using the MERRA-2 dataset. Nearly 2 weeks prior to the central date (lag = 0), at which the zonal-mean zonal wind at 10 hPa and 60°N first becomes negative, westward GW drag (GWD) is significantly enhanced in the lower mesosphere and stratosphere. At 5 days before lag = 0, planetary waves (PWs) of zonal wavenumber 2 (ZWN-2) in the stratosphere are enhanced, while PWs of ZWN-1 are weakened, which are evident from the amplitudes of the PWs and their Eliassen–Palm flux divergence (EPD). To examine the relationship between PWs and GWs, a nonconservative GWD (NCGWD) source term of the linearized quasigeostrophic potential vorticity equation is considered. A ZWN-2 pattern of the NCGWD forcing is developed around z = 55–60 km with a secondary peak around z = 40 km just before the PWs of ZWN-2 in the stratosphere began to enhance. A significant positive correlation between the NCGWD forcing in the upper stratosphere and lower mesosphere (USLM; 0.3–0.1 hPa in the present data) and the PWs of ZWN-2 in the stratosphere (5–1 hPa) exists. This result demonstrates that the amplification of the PWs of ZWN-2 in the stratosphere before the onset of SSW09 is likely related to the generation of PWs by GWD in the USLM, which is revealed by the enhanced downward-propagating PWs of ZWN-2 into the stratosphere from above.
Stochastic Variability of Tropical Cyclone Intensity at the Maximum Potential Intensity Equilibrium
Authors: Nguyen Phuong , Kieu Chanh , Fan Wai-Tong (Louis)
Published: August 2020

This study examines the variability of tropical cyclone (TC) intensity associated with stochastic forcings at the maximum potential intensity (PI) equilibrium. By representing TC intensity as an Itô diffusion process in the framework of TC-scale dynamics, we show from both theoretical and numerical analyses that there exists an invariant intensity distribution whose variance is proportional to the variances of stochastic forcings. This result provides further evidence that TC dynamics possess an intrinsic variability that prevents the TC absolute intensity errors in numerical models from being reduced below an arbitrarily small threshold. Analysis of the invariant intensity distribution at the PI limit reveals also that the stochastic forcing component associated with tangential wind and the warm-core anomaly in the TC central region have the largest contribution to TC intensity variability. These results suggest that future development of stochastic representation in TC models should focus on the tangential wind and thermodynamic structure to capture proper TC intensity random fluctuations.
Description of Atmospheric Aerosol Dynamics Using an Inverse Gaussian Distributed Method of Moments
Authors: Shen J. , Yu M. , Lin J.
Published: August 2020

For nearly 60 years, the lognormal distribution has been the most widely used function in the field of atmospheric science for characterizing atmospheric aerosol size distribution. We verify whether the three-parameter inverse Gaussian distribution (IGD) is a more suitable function than the lognormal distribution for characterizing aerosol size distribution. An attractive feature of IGD is that with it a new method of moments (MOM) can be established for resolving atmospheric aerosol dynamics which is described by a kinetic aerosol dynamics equation, i.e., inverse Gaussian distributed MOM (IGDMOM). The advantage of IGDMOM is that all of its moments can be analytically calculated using a closure moment function inherited from IGD. The precision and efficiency of IGDMOM are verified by comparing it with other recognizable methods in test cases of four representative atmospheric aerosol dynamics. Several key statistical quantities determining aerosol size distributions, including kth moments (k = 0, 1/3, 2/3, and 2), geometric standard deviation, skewness, and kurtosis, are evaluated. IGDMOM has higher precision than the lognormal MOM with nearly identical efficiency. The article provides a novel alternative to atmospheric scientists for solving kinetic aerosol dynamics equations.
An Assessment of MJO Circulation Influence on Air–Sea Interactions for Improved Seasonal Rainfall Predictions over East Africa
Authors: Kimani Margaret , Hoedjes Joost C. B. , Su Zhongbo
Published: August 2020

Rainfall variability affects agriculture planning and water resource management. In extreme flood and drought events, lives and property are destroyed. This study aims to improve East Africa’s seasonal rainfall prediction by determining the impact of the standard eight Real-time Multivariate Madden–Julian Oscillation (MJO) (RMM) phases on rainfall and using sea surface temperature (SST) response to test the predictability of the March–May (MAM) and October–December (OND) main rainfall seasons over a period of 33 years (1981–2013). Pearson correlation patterns, composite maps, and regression analyses were applied, and the Brier skill score (BSS) and correlation coefficients (CC) were utilized as validation metrics. Low correspondence of rainfall to MJO 1 and MJO 2 was observed except for the months of November and December. Seasonally, MAM and OND correlation patterns with MJO 2 revealed enhanced rainfall over the highlands and insignificant correspondence over coastal areas. Conversely, enhanced MJO 8 corresponded to suppressed rainfall during the June–August season over the coast and the eastern highlands. MAM rainfall was shown to be predictable using Maritime Continent SST indices, with a BSS of 0.41, while OND rainfall was shown to be predictable using Atlantic and Maritime Continent SSTs with a BSS of 0.62. Positive and negative MJO 2 corresponded, respectively, to enhanced and suppressed rainfall during the OND season and was confirmed to be related to, respectively, a positive and negative Indian Ocean dipole (IOD). An IOD year could possibly be triggered by changes in MJO 2 amplitudes observed as early peaks between February and June.
The Effect of Explicit Convection on Couplings between Rainfall, Humidity, and Ascent over Africa under Climate Change
Authors: Jackson Lawrence S. , Finney Declan L. , Kendon Elizabeth J. , Marsham John H. , Parker Douglas J. , Stratton Rachel A. , Tomassini Lorenzo , Tucker Simon
Published: August 2020

The Hadley circulation and tropical rain belt are dominant features of African climate. Moist convection provides ascent within the rain belt, but must be parameterized in climate models, limiting predictions. Here, we use a pan-African convection-permitting model (CPM), alongside a parameterized convection model (PCM), to analyze how explicit convection affects the rain belt under climate change. Regarding changes in mean climate, both models project an increase in total column water (TCW), a widespread increase in rainfall, and slowdown of subtropical descent. Regional climate changes are similar for annual mean rainfall but regional changes of ascent typically strengthen less or weaken more in the CPM. Over a land-only meridional transect of the rain belt, the CPM mean rainfall increases less than in the PCM (5% vs 14%) but mean vertical velocity at 500 hPa weakens more (17% vs 10%). These changes mask more fundamental changes in underlying distributions. The decrease in 3-hourly rain frequency and shift from lighter to heavier rainfall are more pronounced in the CPM and accompanied by a shift from weak to strong updrafts with the enhancement of heavy rainfall largely due to these dynamic changes. The CPM has stronger coupling between intense rainfall and higher TCW. This yields a greater increase in rainfall contribution from events with greater TCW, with more rainfall for a given large-scale ascent, and so favors slowing of that ascent. These findings highlight connections between the convective-scale and larger-scale flows and emphasize that limitations of parameterized convection have major implications for planning adaptation to climate change.
Local Rossby Wave Packet Amplitude, Phase Speed, and Group Velocity: Seasonal Variability and Their Role in Temperature Extremes
Authors: Fragkoulidis Georgios , Wirth Volkmar
Published: August 2020

Transient Rossby wave packets (RWPs) are a prominent feature of the synoptic to planetary upper-tropospheric flow at the midlatitudes. Their demonstrated role in various aspects of weather and climate prompts the investigation of characteristic properties like their amplitude, phase speed, and group velocity. Traditional frameworks for the diagnosis of the two latter have so far remained nonlocal in space or time, thus preventing a detailed view on the spatiotemporal evolution of RWPs. The present work proposes a method for the diagnosis of horizontal Rossby wave phase speed and group velocity locally in space and time. The approach is based on the analytic signal of upper-tropospheric meridional wind velocity and RWP amplitude, respectively. The new diagnostics are first applied to illustrative examples from a barotropic model simulation and the real atmosphere. The main seasonal and interregional variability features of RWP amplitude, phase speed, and group velocity are then explored using ERA5 reanalysis data for the time period 1979–2018. Apparent differences and similarities in these respects between the Northern and Southern Hemispheres are also discussed. Finally, the role of RWP amplitude and phase speed during central European short-lived and persistent temperature extremes is investigated based on changes of their distribution compared to the climatology of the region. The proposed diagnostics offer insight into the spatiotemporal variability of RWP properties and allow the evaluation of their implications at low computational demands.
Why Has the Inner Tibetan Plateau Become Wetter since the Mid-1990s?
Authors: Sun Jing , Yang Kun , Guo Weidong , Wang Yan , He Jie , Lu Hui
Published: August 2020

The Inner Tibetan Plateau (ITP; also called the Qiangtang Plateau) appears to have experienced an overall wetting in summer (June, July, and August) since the mid-1990s, which has caused the rapid expansion of thousands of lakes. In this study, changes in atmospheric circulations associated with the wetting process are analyzed for 1979–2018. These analyses show that the wetting is associated with simultaneously weakened westerlies over the Tibetan Plateau (TP). The latter is further significantly correlated with the Atlantic multidecadal oscillation (AMO) on interdecadal time scales. The AMO has been in a positive phase (warm anomaly of the North Atlantic Ocean sea surface) since the mid-1990s, which has led to both a northward shift and weakening of the subtropical westerly jet stream at 200 hPa near the TP through a wave train of cyclonic and anticyclonic anomalies over Eurasia. These anomalies are characterized by an anomalous anticyclone to the east of the ITP and an anomalous cyclone to the west of the ITP. The former weakens the westerly winds, trapping water vapor over the ITP while the latter facilitates water vapor intruding from the Arabian Sea into the ITP. Accordingly, summer precipitation over the ITP has increased since the mid-1990s.
Correction of Inhomogeneities in Observed Land Surface Temperatures over China
Authors: Du Jizeng , Wang Kaicun , Cui Baoshan , Jiang Shaojing
Published: August 2020

Land surface temperature Ts and near-surface air temperature Ta are two main metrics that reflect climate change. Recently, based on in situ observations, several studies found that Ts warmed much faster than Ta in China, especially after 2000. However, we found abnormal jumps in the Ts time series during 2003–05, mainly caused by the transformation from manual to automatic measurements due to snow cover. We explore the physical mechanism of the differences between automatic and manual observations and develop a model to correct the automatic observations on snowy days in the observed records of Ts. Furthermore, the nonclimatic shifts in the observed Ts were detected and corrected using the RHtest method. After corrections, the warming rates for Ts-max, Ts-min, and Ts-mean were 0.21°, 0.34°, and 0.25°C decade−1, respectively, during the 1960–2014 period. The abnormal jump in the difference between Ts and Ta over China after 2003, which was mentioned in existing studies, was mainly caused by inhomogeneities rather than climate change. Through a combined analysis using reanalyses and CMIP5 models, we found that Ts was consistent with Ta both in terms of interannual variability and long-term trends over China during 1960–2014. The Ts minus Ta (Ts − Ta) trend is from −0.004° to 0.009°C decade−1, accounting for from −3.19% to 5.93% (from −3.09% to 6.39%) of the absolute warming trend of Ts (Ta).