terrain following
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2021 ◽  
pp. 174165902110537
Author(s):  
Louise Tanya Wattis

The true crime genre has become synonymous with the serial killer. As such, other narratives dealing with different types of violent criminal subjects have been overlooked in academic and media analyses. The following article explores a subgenre of true crime which has been overlooked—the life story of the violent criminal or “hardman biography.” However, in acknowledging the hardman, the discussion also reveals his presence across fact/fiction boundaries and a range of cultural terrain. Following a discussion of the cultural space this figure occupies, I turn my attention to hardman stories which exist predominantly in the local imaginary and focus on one such text which tells the story of a violent protagonist and cultures of crime and violence in the North of England in the late 1980s and early 1990s. In so doing, I focus on how this text animates cultures of violence and marginality left in the wake of deindustrialization and economic decline, combining this with relevant theoretical and ethnographic work. I conclude by arguing that the text is a further example of the way in which popular criminology can complement and advance academic criminological understandings of crime and violence.



Author(s):  
Suk-Jin Choi ◽  
Joseph B. Klemp

AbstractAn alternative hybrid sigma-pressure terrain-following coordinate is presented here that provides smoother coordinate surfaces over terrain by allowing a more rapid decay of the influence of smaller-scale topographic structures with height. This is accomplished by first defining a reference surface pressure that includes the influence of the underlying topography. A smoothed version of this reference surface pressure is then created that represents the larger scale features of the topography, while the deviations from the smoothed profile contain the smaller-scale terrain structures. In the hybrid-sigma coordinate formulation presented here, the influences of these deviations in the reference surface pressure from their smoothed values are removed more rapidly with increasing height, thereby producing smoother coordinate surfaces. Testing this approach using several idealized simulations demonstrates a significant reduction in the artificial circulations compared to those arising with the basic sigma or the conventional hybrid sigma coordinate, confirming the beneficial aspects of the smoothed hybrid coordinate surfaces. The smoothed hybrid sigma-pressure coordinate proposed here provides flexibility in reducing the influence of the terrain on the coordinate surfaces and can be easily substituted for the basic hybrid sigma-pressure coordinate.



2021 ◽  
Author(s):  
Danping Cai ◽  
Xiu-Qun Yang ◽  
Lingfeng Tao ◽  
Weiping Wang ◽  
Hongming Yan

Abstract Yunnan-Guizhou quasi-stationary front (YGQSF) is a unique weather phenomenon that frequently occurs during winter half year over the Yunnan-Guizhou Plateau in southwestern China. Most of previous studies analyzed it only with synoptic cases. This study investigates the structure, variation, and impact of YGQSF from a climate perspective, using long-term high-resolution atmospheric reanalysis and high-density station records for 1981-2016. An objective method quantifying YGQSF is proposed and three indexes are defined to measure the intensity, frequency, and location of YGQSF, respectively, with the horizontal gradient of air potential temperature at a terrain-following level of sigma 0.995. With these indexes, climatological structure, subseasonal variability as well as climatic impact of YGQSF are comprehensively examined. In climatology, YGQSF as a north-south-oriented low-level front is found to occur the most frequently during January-February-March (JFM), determined predominately by the coldness from the east of the front. The structure of YGQSF identified essentially reflects an obstruction of high-terrain Yunnan (the western part of the plateau) to the low-level cold air mass, which makes near-surface cold northeasterly winds cease westward intruding and veer upward over relatively low-terrain Guizhou, transporting moisture upward and forming low clouds. A sharp climate contrast is thus formed between two sides of YGQSF: cold, sunless, and continuously rainy Guizhou versus warm and sunny Yunnan. Furthermore, YGQSF features significant subseasonal variations with periods at around 30d and 60d largely in its intensity. Anomalously strong YGQSF events which are caused 75% by the cold anomaly from the east but less than 17% by the warm anomaly from the west yield different anomalous structures, but consistently amplify the sharp climate contrast between Yunnan and Guizhou.



2021 ◽  
Author(s):  
Matthias Göbel ◽  
Stefano Serafin ◽  
Mathias Walter Rotach

Abstract. Numerically accurate budgeting of the forcing terms in the governing equations of a numerical weather prediction model is hard to achieve. Because individual budget terms are generally two to three orders of magnitude larger than the resulting tendency, exact closure of the budget can only be achieved if the contributing terms are calculated consistently with the model numerics. We present WRFlux, an open-source software that allows precise budget evaluation for the WRF model, as well as transformation of the budget equations from the terrain-following grid of the model to the Cartesian coordinate system. The theoretical framework of the numerically consistent coordinate transformation is also applicable to other models. We demonstrate the performance and a possible application of WRFlux with an idealized simulation of convective boundary layer growth over a mountain range. We illustrate the effect of inconsistent approximations by comparing the results of WRFlux with budget calculations using a lower-order advection operator and two alternative formulations of the coordinate transformation. With WRFlux, the sum of all forcing terms for potential temperature, water vapor mixing ratio and momentum agrees with the respective model tendencies to high precision. In contrast, the approximations lead to large residuals: The root mean square error between the sum of the diagnosed forcing terms and the actual tendency is one to three orders of magnitude larger than with WRFlux. Furthermore, WRFlux decomposes the resolved advection into mean advective and resolved turbulence components, which is useful in the analysis of large-eddy simulation output.



2021 ◽  
Vol 8 ◽  
Author(s):  
Loïc Van Audenhaege ◽  
Emmeline Broad ◽  
Katharine R. Hendry ◽  
Veerle A. I. Huvenne

Recent advances in deep-sea exploration with underwater vehicles have led to the discovery of vertical environments inhabited by a diverse sessile fauna. However, despite their ecological importance, vertical habitats remain poorly characterized by conventional downward-looking survey techniques. Here we present a high-resolution 3-dimensional habitat map of a vertical cliff hosting a suspension-feeding community at the flank of an underwater glacial trough in the Greenland waters of the Labrador Sea. Using a forward-looking set-up on a Remotely Operated Vehicle (ROV), a high-resolution multibeam echosounder was used to map out the topography of the deep-sea terrain, including, for the first time, the backscatter intensity. Navigational accuracy was improved through a combination of the USBL and the DVL navigation of the ROV. Multi-scale terrain descriptors were derived and assigned to the 3D point cloud of the terrain. Following an unsupervised habitat mapping approach, the application of a K-means clustering revealed four potential habitat types, driven by geomorphology, backscatter and fine-scale features. Using groundtruthing seabed images, the ecological significance of the four habitat clusters was assessed in order to evaluate the benefit of unsupervised habitat mapping for further fine-scale ecological studies of vertical environments. This study demonstrates the importance of a priori knowledge of the terrain around habitats that are rarely explored for ecological investigations. It also emphasizes the importance of remote characterization of habitat distribution for assessing the representativeness of benthic faunal studies often constrained by time-limited sampling activities. This case study further identifies current limitations (e.g., navigation accuracy, irregular terrain acquisition difficulties) that can potentially limit the use of deep-sea terrain models for fine-scale investigations.



2021 ◽  
Author(s):  
Jerome Chanut ◽  
James Harle ◽  
Tim Graham ◽  
Laurent Debreu

<p>The NEMO platform possesses a versatile block-structured refinement capacity thanks to the AGRIF library. It is however restricted up to versions 4.0x, to the horizontal direction only. In the present work, we explain how we extended the nesting capabilities to the vertical direction, a feature which can appear, in some circumstances, as beneficial as refining the horizontal grid.</p><p>Doing so is not a new concept per se, except that we consider here the general case of child and parent grids with possibly different vertical coordinate systems, hence not logically defined from each other as in previous works. This enables connecting together for instance z (geopotential), s (terrain following) or eventually ALE (Arbitrary Lagrangian Eulerian) coordinate systems. In any cases, two-way exchanges are enabled, which is the other novel aspect tackled here.  </p><p>Considering the vertical nesting procedure itself, we describe the use of high order conservative and monotone polynomial reconstruction operators to remap from parent to child grids and vice versa. Test cases showing the feasibility of the approach are presented, with particular attention on the connection of s and z grids in the context of gravity flow modelling. This work can be considered as a preliminary step towards the application of the vertical nesting concept over major overflow regions in global realistic configurations. The numerical representation of these areas is indeed known to be particularly sensitive to the vertical coordinate formulation. More generally, this work illustrates the typical methodology from the development to the validation of a new feature in the NEMO model.</p>



2021 ◽  
Author(s):  
Hock Kiet Wong ◽  
Ching-Yuan Ma ◽  
Chi-Jyun Ko ◽  
Yih-Chin Tai

<p>The movement of a debris flow is channelized by the mountain topography. It slows down and begins to deposit, forming the so-called debris-flow fan, when the slope is gentle. Since the flow body is composed of solid grains with interstitial fluid, the solid fraction may vary and plays a crucial role in the deposition process. In the present study, an entrainment-deposit law together with the two-phase model for grain-fluid flows (Tai et al., 2019) is proposed for describing the development of a debris flow fan. The model equations are derived in a terrain-following coordinate system, in which the coordinates are in coincidence with the topographic surface and the deposition/erosion is treated as the sub-topography. Numerical validation is performed against flume experiments (Tsunetaka et al., 2019), where the sediment-water mixture is released from a channel and merging into a gentle inclined flat plain via a steady water inflow. In this study, we shall illustrate the impacts of the sediment concentration on the evolution of the debris-flow fan, such as the location, distribution, geometry of debris-flow fan as well as the flow paths. </p>



2021 ◽  
Author(s):  
Stephanie Westerhuis ◽  
Oliver Fuhrer

<p>Fog and low stratus pose a major challenge for numerical weather prediction (NWP) models. Despite high resolution in the horizontal (~1 km) and vertical (~20 m), operational NWP models often fail to accurately predict fog and low stratus. This is a major issue at airports which require visibility predictions, or for energy agencies estimating day-ahead input into the electrical grid from photovoltaic power.</p><p>Most studies dedicated to fog and low stratus forecasts have focused on the physical parameterisations or grid resolutions. We illustrate how horizontal advection at the cloud top of fog and low stratus in a grid with sloping vertical coordinates leads to spurious numerical diffusion and subsequent erroneous dissipation of the clouds. This cannot be prevented by employing a higher-order advection scheme. After all, the formulation of the terrain-following vertical coordinate plays a crucial role in regions which do not exhibit perfectly flat orography. We suggest a new vertical coordinate formulation which allows for a faster decay of the orographic signal with altitude and present its positive impact on fog and low stratus forecasts. Our experiments indicate that smoothing of the vertical coordinates at low altitudes is a crucial measure to prevent premature dissipation of fog and low stratus in high-resolution NWP models.</p>



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