We investigate the characteristics of a dust-devil-like vortex (DDLV) observed using thermal image velocimetry (TIV) at a sports ground in Tokyo. Thermal image velocimetry provides unique ...observations of the two-dimensional velocity distribution for a DDLV with high spatio–temporal resolution (i.e., tens of cm s
−1
) near the ground. Two DDLVs were detected, one each in summer and winter, and the quantitative features of the larger, stronger DDLV in the winter are examined. The size and strength of the detected DDLV, which are quantified using TIV, are within the ranges reported in past observations and numerical simulations of dust devils. The vortex appears at the boundary of a cold-air current near a 55-m building wall, and persists for more than 3 min.
A central-moments-based lattice Boltzmann model for large-eddy simulation of neutrally-stratified turbulent flows is described. Through comparative simulations of the airflow within and above a ...homogeneous plant canopy, the performance of the model is evaluated with respect to a conventional large-eddy-simulation model based on the incompressible Navier–Stokes equations. Simulated turbulence statistics, such as the mean velocity, velocity variances, velocity skewness, and power spectra, are shown to be almost identical between the two models. The spatial structure of coherent eddies and their maintenance processes are also confirmed to be properly represented by the lattice Boltzmann method through analysis of the turbulence kinetic energy budget and spatial two-point correlation functions. Using the simulated results, the energetics of the streamwise-elongated streaky structures commonly observed over vegetation and urban canopies are examined. While the short-wavelength components of the shear-generated streamwise kinetic energy are redirected rapidly by pressure to the lateral and vertical velocity components, long-wavelength energy tends to remain in the streamwise velocity component, which is dissipated in relatively slower processes. Consequently, the streaky structures persist in the streamwise velocity component.
This study uses a numerical simulation to examine the local mean flow similarity within an urban roughness sublayer (RSL). The simulations are conducted using a realistic building geometry for the ...central area of Tokyo under three different inflow conditions. The inflow properties are controlled by changing the surface geometries in the upwind direction, which results in various ratios of boundary-layer height to roughness height in the target region. The local mean wind velocities within the RSL, which vary significantly in space, are proportional to each other in all simulations, regardless of the inflow conditions. The velocity within the RSL is represented by the friction velocity, which is estimated from the Reynolds stress profile in the inertial sublayer. The behaviour of the wake turbulence behind isolated high-rise buildings differs considerably among the inflow conditions. Velocity persists for long distances downstream in cases with a low boundary- layer height relative to an isolated building, whereas it diffuses rapidly in cases with a higher boundary-layer height. This effect can propagate into the RSL and modify the mean flow similarity within the sublayer.
A double-distribution-function lattice Boltzmann model for large-eddy simulations of a passive scalar field in a neutrally stratified turbulent flow is described. In simulations of the scalar ...turbulence within and above a homogeneous plant canopy, the model’s performance is found to be comparable with that of a conventional large-eddy simulation model based on the Navier–Stokes equations and a scalar advection–diffusion equation in terms of the mean turbulence statistics, budgets of the second moments, power spectra, and spatial two-point correlation functions. For a top-down scalar, for which the plant canopy serves as a distributed sink, the variance and flux of the scalar near the canopy top are predominantly determined by sweep motions originating far above the canopy. These sweep motions, which have spatial scales much larger than the canopy height, penetrate deep inside the canopy and cause scalar sweep events near the canopy floor. By contrast, scalar ejection events near the canopy floor are induced by coherent eddies generated near the canopy top. The generation of such eddies is triggered by the downward approach of massive sweep motions to existing wide regions of weak ejective motions from inside to above the canopy. The non-local transport of scalars from above the canopy to the canopy floor, and vice versa, is driven by these eddies of different origins. Such non-local transport has significant implications for the scalar variance and flux budgets within and above the canopy, as well as the transport of scalars emitted from the underlying soils to the atmosphere.
Malignant lymphoma developing during anti-PD-1 antibody treatment is extremely rare. A 74-year-old female was admitted with left hypochondrial pain. She was diagnosed with squamous cell carcinoma of ...the right upper lobe of the lung, and had undergone surgery and postoperative chemotherapy three years prior. Needle biopsy of a mediastinal lymph node revealed recurrent lung cancer (LC). Pembrolizumab (PEM) monotherapy was started as salvage treatment. Although her lymphadenopathy improved, thrombocytopenia and splenomegaly developed during treatment with nine doses of PEM. Laboratory findings included anemia, increased lactate dehydrogenase, and soluble interleukin-2 receptor levels of 6379 U/mL. Flow cytometry of peripheral blood and bone marrow showed CD20
+
, κ ≪ λ cell populations.
IGH-BCL2
fusion was detected by fluorescence in situ hybridization in bone marrow. Positron emission tomography showed abnormal uptake in tonsils, both cervical lymph nodes, mediastinum (different location from the recurrent LC), spleen, and abdominal cavity. Follicular lymphoma (FL) grade 1/2 was histologically diagnosed by tonsillar biopsy. She achieved a complete metabolic response (CMR) after rituximab monotherapy on PEM discontinuation. Relapsed FL was diagnosed by submandibular gland biopsy four months after restarting PEM and she achieved a second CMR after rituximab-containing chemotherapy. We describe the first case of newly diagnosed FL during PEM treatment.
Respiratory tract infections (RTIs) are the most common diseases globally among children. This study aimed to assess the epidemiology of admission-requiring pediatric RTI cases and evaluate the ...effect of the pathogen type on the length of hospital stay (LOS) using the FilmArray® respiratory panel, a multiplex PCR test. The age-specific distribution and seasonality of viruses were investigated between March 26, 2018 and April 12, 2019. Multivariable linear regression analyses were performed to evaluate the effect of pathogen type and coinfection on LOS. Among 153 hospitalized RTI patients, respiratory syncytial virus was the leading cause of hospitalization in infants < 12 months of age (27.7%). Human metapneumovirus and parainfluenza virus were also major causes of hospitalization in patients aged 2–3 years (22.6% and 22.6%, respectively). In the multivariable linear regression model excluding rhinovirus/enterovirus, there was a significant association between viral coinfection and longer LOS (p = 0.012), while single viral infection of any type was not positively correlated with LOS. This study revealed the epidemiology of admission-requiring pediatric RTIs.
Overview of the PALM model system 6.0 Maronga, Björn; Banzhaf, Sabine; Burmeister, Cornelia ...
Geoscientific Model Development,
03/2020, Letnik:
13, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In this paper, we describe the PALM model system 6.0. PALM (formerly an abbreviation for Parallelized Large-eddy Simulation Model and now an independent name) is a Fortran-based code and has been ...applied for studying a variety of atmospheric and oceanic boundary layers for about 20 years. The model is optimized for use on massively parallel computer architectures. This is a follow-up paper to the PALM 4.0 model description in Maronga et al. (2015). During the last years, PALM has been significantly improved and now offers a variety of new components. In particular, much effort was made to enhance the model with components needed for applications in urban environments, like fully interactive land surface and radiation schemes, chemistry, and an indoor model. This paper serves as an overview paper of the PALM 6.0 model system and we describe its current model core. The individual components for urban applications, case studies, validation runs, and issues with suitable input data are presented and discussed in a series of companion papers in this special issue.
Urban geometry and materials combine to create complex spatial, temporal and directional patterns of longwave infrared (LWIR) radiation. Effective anisotropy (or directional variability) of thermal ...radiance causes remote sensing (RS) derived urban surface temperatures to vary with RS view angles. Here a new and novel method to resolve effective thermal anisotropy processes from LWIR camera observations is demonstrated at the Comprehensive Outdoor Scale MOdel (COSMO) test site. Pixel-level differences of brightness temperatures reach 18.4 K within one hour of a 24-h study period. To understand this variability, the orientation and shadowing of surfaces is explored using the Discrete Anisotropic Radiative Transfer (DART) model and Blender three-dimensional (3D) rendering software. Observed pixels and the entire canopy surface are classified in terms of surface orientation and illumination. To assess the variability of exitant longwave radiation (MLW) from the 3D COSMO surface (MLW3D), the observations are prescribed based on class. The parameterisation is tested by simulating thermal images using a camera view model to determine camera perspectives of MLW3D fluxes. The mean brightness temperature differences per image (simulated and observed) are within 0.65 K throughout a 24-h period. Pixel-level comparisons are possible with the high spatial resolution of MLW3D and DART camera view simulations. At this spatial scale (<0.10 m), shadow hysteresis, surface sky view factor and building edge effects are not completely resolved by MLW3D. By simulating apparent brightness temperatures from multiple view directions, effective thermal anisotropy of MLW3D is shown to be up to 6.18 K. The developed methods can be extended to resolve some of the identified sources of sub-facet variability in realistic urban settings. The extension of DART to the interpretation of ground-based RS is shown to be promising.
•Diurnal longwave infrared radiation observations of the COSMO urban canopy•Method for per-pixel dynamic classification of observations•Brightness temperature for all surfaces at high spatial and temporal resolution•Explanation of observed variability based on surface orientation and shading•Brightness temperatures used to model urban thermal anisotropy
We used numerical simulations to investigate the general relationship between urban morphology and the intensity of wind gusts in built-up areas at the pedestrian level. The simulated urban boundary ...layer developed over a 19.2 km (length)
×
4.8 km (width)
×
1.0 km (height) simulation domain, with 2-m resolution in all directions, to explicitly resolve the detailed shapes of buildings and the flow at the pedestrian level. This complex computation was accomplished using the lattice Boltzmann method and by implementing a large-eddy simulation model. To generalize the results, a new parameter that expresses the intensity of gusts (the gust index,
U
~
m
a
x
)
was defined as the local maximum wind speed divided by the freestream velocity. In addition, this parameter was decomposed into the mean wind-speed ratio,
U
~
and turbulent gust ratio,
U
~
′
to evaluate the qualities of gusts. These parameters were useful for quantitatively comparing the gust intensities within urban canopies at different locations or even among different experiments. In addition, the entire horizontal domain was subdivided into homogeneous square patches, in which both the simulated gust parameters and the morphological characteristics of building geometries were averaged. This procedure masked the detailed structure of individual buildings but retained the bulk characteristics of the urban morphology. At the pedestrian level, the gust index decreased with increasing building cover. Compared to
U
~
, the quantity
U
~
′
notably contributed to the index throughout the range of plan area index
(
λ
p
)
values. The dependences of all normalized wind-speed ratios transiently changed at
λ
p
=
0.28
. In cases where
λ
p
<
0.28
,
U
~
decreased with increasing
λ
p
, although
U
~
′
was almost constant. In cases where
λ
p
>
0.28
,
U
~
was almost constant and
U
~
′
decreased with increasing
λ
p
. This was explained by the change in flow regimes within the building canyon. At a higher elevation above the canopy layer,
λ
p
becomes less relevant to normalized wind-speed ratios, and instead the aerodynamic roughness length became important.
Sea breeze is closely related to the living environment in coastal-urban regions. Therefore, the framework for sea-breeze detection is crucial. We proposed a framework to derive a two-dimensional ...distribution of sea-breeze front (SBF) using geostationary satellite images. The framework includes the application of morphological snake algorithm into visible band images for automated detection of the cumulus cloud-lines associated with SBF. The verification was undertaken by comparing the passage time of the cloud-line with the arrival time of the SBF estimated from ground observation. The results show that the cloud-line was reasonably able to represent the arrival time of the SBF with a bias time of 20 min and within a distance of 3 km. The mean penetration speed obtained from the cloud-lines passage was slightly slower than that estimated from the arrival time of SBF (1.4 ms−1 and 1.5 ms−1, respectively). In certain cases, the cloud-lines passage was found to be behind the SBF more than 5 km, particularly in the city center. This indicated the enhanced updraft due to urban-heat-island circulation potentially caused the delayed of cloud-line propagation in certain prevailing wind condition.
•The cloud-line passage represents the arrival time of the sea-breeze front•Enhanced updraft over the urbanized area causes cumulus cloud-line to dissipate longer•Slower inland-penetration speed of the sea-breeze front exists over the urbanized area
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