natural variability
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2021 ◽  
Author(s):  
Andrew Mitchell ◽  
Sophia Zubrycky ◽  
Scott McDougall ◽  
Jordan Aaron ◽  
Mylène Jacquemart ◽  
...  

Abstract. Debris flows affect people and infrastructure around the world, and as a result, many numerical models and modelling approaches have been developed to simulate their impacts. Observations from instrumented debris-flow channels show that variability in inflow depth, velocity and discharge in real debris flows is much higher than what is typically used in numerical simulations. However, the effect of this natural variability on numerical model outputs is not well known. In this study, we examine the effects of using complex inflow time series within a single-phase runout model utilizing a Voellmy flow-resistance model. The interactions between model topography and flow-resistance were studied first using a simple triangular hydrograph, which showed simulated discharges change because of local slopes and Voellmy parameters. Next, more complex inflows were tested using time series based on 24 real debris-flow hydrographs initiated from three locations. We described a simple method to scale inflow hydrographs by defining a target event volume and maximum allowable peak discharge. The results showed a large variation in simulated flow depths and velocities arising from the variable inflow. The effects of variable inflow conditions were demonstrated in simulations of two case histories of real debris flows, where the variation in inflow leads to significant variations in the simulation outputs. The real debris-flow hydrographs were used to provide an indication of the range of impacts that may result from the natural variability in inflow conditions. These results demonstrate variation in inflow conditions can lead to reasonable estimates of the potential variation in impacts.


2021 ◽  
pp. 095679762110306
Author(s):  
Xiaomei Zhou ◽  
Shruti Vyas ◽  
Jinbiao Ning ◽  
Margaret C. Moulson

Everyday face recognition presents a difficult challenge because faces vary naturally in appearance as a result of changes in lighting, expression, viewing angle, and hairstyle. We know little about how humans develop the ability to learn faces despite natural facial variability. In the current study, we provide the first examination of attentional mechanisms underlying adults’ and infants’ learning of naturally varying faces. Adults ( n = 48) and 6- to 12-month-old infants ( n = 48) viewed videos of models reading a storybook; the facial appearance of these models was either high or low in variability. Participants then viewed the learned face paired with a novel face. Infants showed adultlike prioritization of face over nonface regions; both age groups fixated the face region more in the high- than low-variability condition. Overall, however, infants showed less ability to resist contextual distractions during learning, which potentially contributed to their lack of discrimination between the learned and novel faces. Mechanisms underlying face learning across natural variability are discussed.


2021 ◽  
Author(s):  
Alexia Karwat ◽  
Christian L. E. Franzke ◽  
Richard Blender

<p>Long-term reanalysis data sets are needed to determine the natural variability of extra-tropical cyclone tracks and for the assessment of the response to global warming. Using a systematic change-point analysis we provide evidence that the pre-satellite ERA5 data of the Backward Extension (ERA5-BE, covering 1950-1978) is highly compatible with the standard ERA5 (1979-2021) data sets. We observe that the joint ERA5 data from 1950 to 2021 is consistent in all storm-related quantities, allowing long-term studies. Despite the high inter-annual variability, a trend analysis suggests that the intensity of extra-tropical cyclones has increased significantly in the Northern Hemisphere from 1950 to 2021. The propagation speed of extra-tropical cyclones has notably decreased and the North Atlantic cyclone track, in particular, has shifted northward. Furthermore, the number of North Pacific storms increased significantly; these storms exhibit longer life cycles and travel larger distances, while they also grow more slowly. From 1979 to 2021 we find increases in wind gusts and cyclone-related precipitation. The central geopotential height, a measure for storminess, has decreased in both storm track areas. The observed changes originating from potential changes in the atmospheric circulation are the result of natural variability and anthropogenic global warming. Future storm adaptation planning should consider the observed increase in storm-related impacts.</p>


2021 ◽  
Vol 38 (4) ◽  
pp. 461-466
Author(s):  
Franck Boyer ◽  
Walter Renda ◽  
Attilio Pagli

On the ground of an extensive study of topotypes and of the shell morphology documented in comparable Mediterranean populations, Granulina pusaterii Smriglio & Mariottini, 2003 described from the Tunisian Plateau is proved to belong to the natural variability of G. melitensis Smriglio, Mariottini & Rufini, 1998 and it is proposed as junior synonym name of the latter.


2021 ◽  
Vol 603 ◽  
pp. 126979
Author(s):  
Lalit Pal ◽  
Chandra Shekhar Prasad Ojha ◽  
A.P. Dimri

2021 ◽  
Author(s):  
◽  
Ben Nistor

<p>Extreme weather and climate-related events can have pronounced environmental, economic and societal impacts, yet large natural variability within Earth’s constantly evolving climate system challenges the understanding of how these phenomena are changing. Increasingly powerful climate models have made it possible to study how certain factors, including anthropogenic forcings, have modified the likelihood and magnitude of extreme events.  This study examines climate observations, reanalysis fields and model output to assess how weather extremes and climate-related events have changed. Part 1 investigates the detection and attribution of surface climate changes in relation to ozone depletion. Part 2 uses probabilistic event attribution and storyline frameworks to evaluate the role of anthropogenic forcings in altering the risk of extreme 1-day rainfall (RX1D) events for Christchurch, New Zealand in light of an unprecedented rainfall event that occurred in March 2014.  Extremely large simulations of possible weather generated by the weather@home Australia-New Zealand (w@h ANZ) model found ozone forcings induced significant changes globally (< 3 hPa) in simulations of mean sea level pressure for 2013. A clear seasonal response was detected in the Southern Hemisphere (SH) circulation that was consistent with prior studies. Ozone-induced changes to average monthly rainfall were not significant in New Zealand with large natural variability and the limitation of one-year simulations challenging attribution to this climate forcing.  In Christchurch, model and observational data give evidence of human activity increasing the likelihood and magnitude (+17%) of RX1D events despite significant drying trends for mean total rainfall (-66%) in austral summer. For events similar to that observed during March 2014, the fraction of attributable risk (FAR) is estimated to be 27.4%. This result was robust across different spatial averaging areas though is sensitive to the rainfall threshold examined. Unique meteorological conditions in combination with anomalously high sea surface temperatures (SSTs) in the tropical South Pacific were likely important to the occurrence of this extreme event. These results demonstrate how human influence can be detected in present-day weather and climate events.</p>


2021 ◽  
Author(s):  
◽  
Ben Nistor

<p>Extreme weather and climate-related events can have pronounced environmental, economic and societal impacts, yet large natural variability within Earth’s constantly evolving climate system challenges the understanding of how these phenomena are changing. Increasingly powerful climate models have made it possible to study how certain factors, including anthropogenic forcings, have modified the likelihood and magnitude of extreme events.  This study examines climate observations, reanalysis fields and model output to assess how weather extremes and climate-related events have changed. Part 1 investigates the detection and attribution of surface climate changes in relation to ozone depletion. Part 2 uses probabilistic event attribution and storyline frameworks to evaluate the role of anthropogenic forcings in altering the risk of extreme 1-day rainfall (RX1D) events for Christchurch, New Zealand in light of an unprecedented rainfall event that occurred in March 2014.  Extremely large simulations of possible weather generated by the weather@home Australia-New Zealand (w@h ANZ) model found ozone forcings induced significant changes globally (< 3 hPa) in simulations of mean sea level pressure for 2013. A clear seasonal response was detected in the Southern Hemisphere (SH) circulation that was consistent with prior studies. Ozone-induced changes to average monthly rainfall were not significant in New Zealand with large natural variability and the limitation of one-year simulations challenging attribution to this climate forcing.  In Christchurch, model and observational data give evidence of human activity increasing the likelihood and magnitude (+17%) of RX1D events despite significant drying trends for mean total rainfall (-66%) in austral summer. For events similar to that observed during March 2014, the fraction of attributable risk (FAR) is estimated to be 27.4%. This result was robust across different spatial averaging areas though is sensitive to the rainfall threshold examined. Unique meteorological conditions in combination with anomalously high sea surface temperatures (SSTs) in the tropical South Pacific were likely important to the occurrence of this extreme event. These results demonstrate how human influence can be detected in present-day weather and climate events.</p>


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Simon Whitburn ◽  
Lieven Clarisse ◽  
Marie Bouillon ◽  
Sarah Safieddine ◽  
Maya George ◽  
...  

AbstractIn recent years, the interest has grown in satellite-derived hyperspectral radiance measurements for assessing the individual impact of climate drivers and their cascade of feedbacks on the outgoing longwave radiation (OLR). In this paper, we use 10 years (2008–2017) of reprocessed radiances from the infrared atmospheric sounding interferometer (IASI) to evaluate the linear trends in clear-sky spectrally resolved OLR (SOLR) in the range [645–2300] cm−1. Spatial inhomogeneities are observed in most of the analyzed spectral regions. These mostly reflected the natural variability of the atmospheric temperature and composition but long-term changes in greenhouse gases concentrations are also highlighted. In particular, the increase of atmospheric CO2 and CH4 led to significant negative trends in the SOLR of −0.05 to −0.3% per year in the spectral region corresponding to the ν2 and the ν3 CO2 and in the ν4 CH4 band. Most of the trends associated with the natural variability of the OLR can be related to the El Niño/Southern Oscillation activity and its teleconnections in the studied period. This is the case for the channels most affected by the temperature variations of the surface and the first layers of the atmosphere but also for the channels corresponding to the ν2 H2O and the ν3 O3 bands.


Author(s):  
Arindam Basu

Product development is key to survival of any industry with change of time. This article discusses about the process of new product development in textile and apparel industry. Major points considered during this process are demand of customers, availability of new raw materials, sustainability, economic validity and responsibiiity towards nature. Engineering of products is a complicated issue here due to natural variability of textile materials, limitations of fibre available and use of old conventional machineries in many cases.


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