On the Storms Passing Over Southern Baffin Island During Autumn 2005

Although strong storms affect all regions of the Arctic, little research has focused on the details of their structure and evolution—particularly of the storms passing over southern Baffin Island. Such storms form in a variety of locations and often occlude before passing over the region. To study these storms, a field project was conducted at Iqaluit, Nunavut, in the eastern Canadian Arctic in the autumn of 2005. We launched rawinsondes into six storm systems and made detailed measurements that included ice crystal structure and snow accumulation. The storms had quite different histories: some produced strong winds; some produced snow, while others produced rain and freezing precipitation; and three led to record-breaking temperatures. The types of precipitation particles varied greatly, but aggregates and rimed particles dominated. When comparing the six storms, we found numerous similarities between the surface and the vertical atmospheric conditions, but there were also distinct differences.Même si de mauvaises tempêtes s’abattent sur toutes les régions de l’Arctique, peu de recherches ont été effectuées pour connaître les détails de leur structure et de leur évolution, plus particulièrement en ce qui a trait aux tempêtes qui passent dans la région sud de l’île de Baffin. Ces tempêtes se forment dans divers endroits et souvent, elles se ferment avant de passer dans la région. Pour étudier ces tempêtes, des travaux ont été effectués sur le terrain même à Iqaluit, au Nunavut, dans l’est de l’Arctique canadien à l’automne 2005. Nous avons lancé des appareils de radiosondage-radiovent dans six tempêtes et avons pris des mesures détaillées portant notamment sur la structure des cristaux de glace et l’accumulation de neige. La formation des tempêtes était très différente : certaines produisaient des vents violents, d’autres produisaient de la neige, d’autres encore produisaient de la pluie et des précipitations givrantes, et trois tempêtes ont donné lieu à des températures record. Le type de particules de précipitation variait beaucoup, bien que les agrégats et les particules givrées dominaient. En comparant les six tempêtes, nous avons constaté qu’il existait de nombreuses similitudes entre les conditions à la surface et les conditions atmosphériques verticales, mais qu’il y avait aussi de nettes différences

Red Chalk Palimpsest: The Logic of Somba Landscape

This article presents the results of a study on the traditional settlement patterns of the Somba people, living in the department of Atacora, north-western Benin. Adopting a methodology based on both a generative approach and André Corboz’s (1983) territory–palimpsest analogy, the study specifically questions the ‘dispersed’ character of the Somba habitat. Built upon two hypotheses, according to which Tatas Somba settle approximately to pre-existing Tatas and near to watercourses, this study seeks to understand the reasons and conditions of this dispersal throughout history. By cross-checking on-site inventory and geographic information system data allowing to analyse the distances between Tatas, archaeological sites and nearby watercourses, and thus revealing the permanent, the persistent, and the disappeared landscape elements, this article aims to prove that the settlement of the Tatas Somba is not determined by geometrical compositions, landmarks, or infrastructures, but rather by a combination of social, agricultural, environmental, and subsistence factors

UJI KONSENTRASI FORMULA NANOEMULSI SERAI WANGI (Cymbopogon nardus L: Randle) DALAM MENGHAMBAT PERTUMBUHAN JAMUR Phytophthora palmivora Butler. PENYEBAB PENYAKIT BUSUK BUAH KAKAO (Theobroma cacao Linn.) SECARA IN VITRO

Penyakit busuk buah kakao yang disebabkan oleh jamur Phytophthora palmivora Butler. merupakan salah satu penyakit utama yang menyebabkan menurunnya produksi tanaman kakao. Penggunaan nanoemulsi serai wangi merupakan salah satu alternatif untuk mengendalikan penyebab penyakit busuk buah kakao yang ramah lingkungan dan cukup efektif untuk digunakan. Penelitian ini bertujuan untuk mengetahui konsentrasi nanoemulsi serai wangi yang efektif dalam menghambat pertumbuhan jamur P. palmivora penyebab penyakit busuk buah pada kakao secara in vitro. Penelitian telah dilaksanakan di Laboratorium Fitopatologi Jurusan Hama dan Penyakit Tumbuhan Fakultas Pertanian Universitas Andalas dari bulan Juni sampai Agustus 2017. Penelitian menggunakan Rancangan Acak Lengkap (RAL) dengan 7 perlakuan dan 4 ulangan. Perlakuan terdiri dari kontrol, konsentrasi nanoemulsi serai wangi 0,10%, 0,15%, 0,22%, 0,33%, 0,50%, dan fungisida berbahan aktif cuprum dengan konsentrasi 0,10% sebagai pembanding. Parameter yang diamati adalah luas koloni, pertumbuhan jamur P. palmivora, jumlah sporangium, berat basah dan berat kering. Data dianalisis dengan Uji F dan dilanjutkan dengan uji Least Significant Difference (LSD) pada taraf nyata 5%. Hasil penelitian menunjukkan bahwa konsentrasi yang paling efektif dalam menekan pertumbuhan jamur P. palmivora adalah konsentrasi nanoemulsi serai wangi 0,50% dengan efektivitas penekanan pada luas koloni, jumlah sporangium, berat basah, dan berat kering koloni secara berurutan yaitu 94,81%, 100%, 87%, dan 60%. Kata kunci: Kakao, busuk buah, nanoemulsi seraiwangi, Phytophthora palmivor

The Wind Energy Potential of Iceland

AbstractDownscaling simulations performed with the Weather Research and Forecasting (WRF) model were used to determine the large-scale wind energy potential of Iceland. Local wind speed distributions are represented by Weibull statistics. The shape parameter across Iceland varies between 1.2 and 3.6, with the lowest values indicative of near-exponential distributions at sheltered locations, and the highest values indicative of normal distributions at exposed locations in winter. Compared with summer, average power density in winter is increased throughout Iceland by a factor of 2.0–5.5. In any season, there are also considerable spatial differences in average wind power density. Relative to the average value within 10 km of the coast, power density across Iceland varies between 50 and 250%, excluding glaciers, or between 300 and 1500 W m−2 at 50 m above ground level in winter. At intermediate elevations of 500–1000 m above mean sea level, power density is independent of the distance to the coast. In addition to seasonal and spatial variability, differences in average wind speed and power density also exist for different wind directions. Along the coast in winter, power density of onshore winds is higher by 100–700 W m−2 than that of offshore winds. Based on these results, 14 test sites were selected for more detailed analyses using the Wind Atlas Analysis and Application Program (WAsP)

The triggering factors of the Móafellshyrna debris slide in northern Iceland: Intense precipitation, earthquake activity and thawing of mountain permafrost

On the 20th September 2012, a large debris slide occurred in the Móafellshyrna Mountain in the Tröllaskagi peninsula, central north Iceland. Our work describes and discusses the relative importance of the three factors that may have contributed to the failure of the slope: intense precipitation, earthquake activity and thawing of ground ice. We use data from weather stations, seismometers, witness reports and field observations to examine these factors. The slide initiated after an unusually warm and dry summer followed by a month of heavy precipitation. Furthermore, the slide occurred after three seismic episodes, whose epicentres were located ~60km NNE of Móafellshyrna Mountain. The main source of material for the slide was ice-rich colluvium perched on a topographic bench. Blocks of ice-cemented colluvium slid and then broke off the frontal part of the talus slope, and the landslide also involved a component of debris slide, which mobilized around 312,000-480,000m(3) (as estimated from field data and aerial images of erosional morphologies). From our analysis we infer that intense precipitation and seismic activity prior to the slide are the main preparatory factors for the slide. The presence of ice-cemented blocks in the slide's deposits leads us to infer that deep thawing of ground ice was likely the final triggering factor. Ice-cemented blocks of debris have been observed in the deposits of two other recent landslides in northern Iceland, in the Torfufell Mountain and the Árnesfjall Mountain. This suggests that discontinuous mountain permafrost is degrading in Iceland, consistent with the decadal trend of increasing atmospheric temperature in Iceland. This study highlights a newly identified hazard in Iceland: landslides as a result of ground ice thaw. Knowledge of the detailed distribution of mountain permafrost in colluvium on the island is poorly constrained and should be a priority for future research in order to identify zones at risk from this hazard

Workshop on Raising Data using the RDBES and TAF (WKRDBESRaiseTAF; outputs from 2022 meeting)

41 páginasThe Workshop on Raising Data using the RDBES and TAF (WKRDBES-Raise&TAF) met online (26–30 of September 2022) to evaluate the use of the Regional Database and Estimation System (RDBES) format to reproduce the 2022 InterCatch input and output, identifying a Transparent Assessment Framework (TAF) structure to organize the intermediate steps and to propose standardized output formats. The main outcomes of WKRDBES-Raise&TAF were: · RDBES provides sufficient support for current national estimation protocols. However, some minor issues were reported that hampered an exact reproduction of the estimates. Therefore, adaptations of the data model should not be excluded completely. · All the input to stock assessment that InterCatch currently provides, could be reproduced. The participants started from the current stock extracts that can be downloaded from InterCatch. · A workflow was proposed with a national TAF repository for each country, a stock estimation repository and a stock assessment repository. The intermediate output of those repositories will be stored in an ‘intermediate output database’ and depending on the user role, you will get access to the relevant stages in this workflow. · The following requirements for the standard output formats were defined: they cannot be more restrictive than the InterCatch input and output format; they should present measures of uncertainty and sample sizes (for national estimates) and should have a configurable domain definition (for national estimates). Despite those successful outcomes, the current plan for transition to an operational system was concluded to be too optimistic. WKRDBES-Raise&TAF therefore recommends to the Working Group on Governance of the Regional Database and Estimation System (WGRDBESGOV) to revise the roadmap and allow RDBES to be in a test phase also for 2023. WKRDBES-Raise&TAF felt the need to test the proposed workflow on a small scale and therefore recommends to the WGRDBESGOV to arrange a workshop where two stocks (pok.27.3a46 (Saithe (Pollachius virens) in Subareas 4, 6 and Division 3.a (North Sea, Rockall and West of Scotland, Skagerrak and Kattegat) and wit.27.3a47d (Witch (Glyptocephalus cynoglossus) in Subarea 4 and Divisions 3.a and 7.d (North Sea, Skagerrak and Kattegat, eastern English Channel)) will be set up to go through the whole flow.Peer reviewe

Channelling of high-latitude boundary-layer flow

International audienceDue to the stability of the boundary-layer stratification, high-latitude winds over complex terrain are strongly affected by blocking and channelling effects. Consequently, at many low-lying communities in the Canadian Archipelago, including Cape Dorset and Iqaluit considered in this study, surface winds for the most part are from two diametrically opposed directions, following the orientation of the elevated terrain. Shifts between the two prevailing wind directions can be sudden and are associated with geostrophic wind directions within a well defined narrow range. To quantitatively investigate the role of large-scale pressure gradients and the quasi-geostrophic overlying flow, an idealised dynamical system for the evolution of channelled surface winds is derived from the basic equations of motion, in which stability of stationary along-channel wind directions is described as a function of the geostrophic wind. In comparison with long-term horizontal wind statistics at the two locations it is shown that the climatologically prevailing wind directions can be identified as stationary states of the idealised wind model, and that shifts between prevailing wind directions can be represented as stability transitions between these stationary states. In that sense, the prevailing local wind conditions can be interpreted as attracting states of the actual flow, with observed surface winds adjusting to a new stable direction as determined by the idealised system within 3?9 h. Over these time-scales and longer it is therefore advantageous to determine the relatively slow evolution of the observationally well-resolved large-scale pressure distribution, instead of modelling highly variable surface winds directly. The simplified model also offers a tool for dynamical downscaling of global climate simulations, and for determining future scenarios for local prevailing wind conditions. In particular, it allows an estimation of the sensitivity of local low-level winds to changes in the large-scale atmospheric circulation

La réalité virtuelle au service de l’apprentissage de la géométrie descriptive : retour vers Monge

Cet article s’intéresse aux avantages pédagogiques de la réalité virtuelle et à son application dans le cas de l’apprentissage de la géométrie descriptive. Il décrit l’implémentation et les premiers résultats d’une application en réalité virtuelle destinée à soutenir l’enseignement de la géométrie descriptive dans la Faculté d’architecture, d’ingénierie architecturale, d’urbanisme de l’UCLouvain