Climate and climate change in western canada as simulated by the Canadian regional climate model

Abstract

A þrst climate simulation performed with the novel Canadian Regional Climate Model (CRCM) is presented. The CRCM is based on fully elastic non‐hydrostatic þeld equations, which are solved with an efþcient semi‐implicit semi‐Lagrangian (SISL) marching algorithm, and on the parametrization package of subgrid‐scale physical effects of the second‐generation Canadian Global Climate Model (GCMII). Two 5‐year integrations of the CRCM nested with GCMII simulated data as lateral boundary conditions are made for conditions corresponding to current and doubled CO₂ scenarios. For these simulations the CRCM used a grid size of 45 km on a polar‐stereographic projection, 20 scaled‐height levels and a time step of 15 min; the nesting GCMII has a spectral truncation of T32, 10 hybrid‐pressure levels and a time step of 20 min. These simulations serve to document: (1) the suitability of the SISL numerical scheme for regional climate modelling, (2) the use of GCMII physics at much higher resolution than in the nesting model, (3) the ability of the CRCM to add realistic regional‐scale climate information to global model simulations, and (4) the climate of the CRCM compared to that of GCMII under two greenhouse gases (GHG) scenarios.     

Cause of scale inconsistencies in DORIS time series

In this paper we analyze the scale of the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) solutions with respect to DORIS extension of the International Terrestrial Reference Frame (ITRF) for Precise Orbit Determination DPOD2014. The main goal is to explain the scale inconsistencies and to find the optimal solution reaching low-biased and consistent scale time series. Our analysis profits from 4 different strategies based only on the Geodetic Observatory Pecný analysis center solution, using DORIS exchange format data 2.2. A difference in the sequence of the solutions directly corresponds to one of the changes in the solution settings: data elevation dependent weighting, application of data validity indicators and application of phase center - reference point correction. We process multi-satellite and single-satellite solutions for the time period 2011.0–2017.0. Our analysis examines scale inconsistency issues in 2011/2012 and in 2015. The scale increment in 2011/2012 is explained as a result of the concurrence of changes in satellite constellation and change in the provider data validity standards for Cryosat-2 and Jason-2 satellites. The scale increment in 2015 is explained as the effect of change in the standards for phase center - reference center corrections for Saral, Jason-2 and Cryosat-2 satellites. Moreover, comparing the solutions with and without elevation dependent data downweighting using the same elevation cutoff (10°), we found a significant reduction of scale bias and scale variation applying the data downweighting. The data downweighting improved also the station positioning repeatability. We demonstrate that the solution, which is completely free from the additional data associated with observations in DORIS exchange format 2.2 and includes the data downweighting law, eventuates in a consistent scale time series with the lowest offset with respect to DPOD2014 (version 1.0) (12.7 ± 2.3 mm for 2011.0–2017.0). The only remaining scale issue is the part of 2011/2012 increment of around 5 mm, explained by a change in the DORIS satellite constellation.     

Local traditions as a means for commercial production of historical beers: The case of Vossaøl,Norway

The aim of the article is to analyse challenges facing the commercial production of historical beers, which are ‘extinct’ beers. The concept of ‘fictive terroir’ is introduced to emphasize these challenges. The author addresses the following questions: What kind of knowledge is needed to produce historical beers? How can this knowledge be acquired? How can it be used commercially in craft breweries? The studied case is Vossaøl, a craft beer imitation of a beer produced in the early 19th century. The data were obtained from written sources and interviews with local home brewers and brewers at Voss Brewery in Norway. The study revealed the need to reconstruct the terroir in the early 19th century. Additionally, Voss Brewery had to acquire knowledge about how to process and combine the ingredients, which included the traditional yeast (kveik). Involving traditional home brewers was crucial to determine how ingredients could be combined to produce Vossaøl. The author concludes that a synthetic knowledge base was a useful point of departure in this respect. Participation in the traditional culture of brewing proved an important means when working with this knowledge base. The results are interesting in the broader context of the reconstruction of beverages and food.     

Pliocene–Quaternary fluvial and aeolian records in the Souss Basin, southwest Morocco: A geomorphological model

The Souss Basin in SW Morocco is filled by Pliocene–Quaternary fluvial, fluvio-lacustrine and aeolian sediments, representing an excellent archive of palaeohydrology, palaeoclimate and the effects of crustal deformation. In general these sediments indicate stream-dominated alluvial systems, influenced by fluctuations in climate (humidity/aridity). Lakes developed within the basin around the Pliocene–Pleistocene transition and persisted into the Early Pleistocene. During this early period, relatively humid conditions are indicated by the dominance of coarse-grained sedimentation in the upper reaches of fluvial systems, the existence of large lakes and the considerable sediment thicknesses in the centre of the basin. Uplift of the surrounding mountain ranges contributed to piedmont formation by providing large amounts of coarse-grained material that accumulated at the lowland margin. Climatic deterioration in the Middle Pleistocene was accompanied by progressively more irregular and disrupted fluvial regimes. These trends were evident in the Late Pleistocene and became clearer after the mid-Holocene, with aeolian activity becoming the dominant sedimentary agent. Differences between upstream and downstream depositional regimes became marked: while coarse-grained sedimentation has characterized the upper reaches of wadi catchments, fine-grained sedimentation has prevailed downstream. Hiatuses in sedimentation throughout the Pliocene and Quaternary are marked by palaeosol horizons interbedded within the sedimentary sequences, indicating alternate vegetated (stable) and unvegetated (unstable/active) phases (biostasy and ‘rhexistasy’).     

A structural model for the seismicity of the Arudy (1980) epicentral area (Western Pyrenees, France)

The Western Pyrenees presents a diffuse and moderate ( M ≤ 5.7) instrumental seismicity. It nevertheless historically suffered from strong earthquakes (I = IX MSK). The seismic sources of these events are not yet clearly identified. We focus on the Arudy (1980) epicentral area ( M = 5.1) and propose here the reactivation of early Cretaceous normal faults of the Iberian margin as a potential source. The late Cretaceous inversion of this basin, first in a left-lateral strike-slip mode and then in a more frontal convergence, resulted in a pop-up geometry. This flower structure attests of the presence of a deep crustal discontinuity.
The present-day geodynamic arrangement suggests that this accident is reactivated in a right lateral mode. This reactivation leads to a strain partitioning between the deep discontinuity that accommodates the lateral component of the motion and shallow thrusts, rooted on this discontinuity. These thrusts accommodate the shortening component of the strain. The distribution of the instrumental seismicity fits well the structural model of the Arudy basin. Whatever the compressive regional context, the structural behaviour of the system explains too the extensive stress tensor determined for the Arudy crisis if we interpret it in terms of strain ellipsoid. Indeed numerical modelling has shown that this concomitant activity of strike-slip and thrust faulting results in an extensive component that can rise 50 per cent of the finite strain.
We identify too a 25–30 km long potential seismic source for the Arudy area. The size of the structure and its potential reactivation in a strike-slip mode suggest that a maximum earthquake magnitude of ∼6.5 could be expected. The extrapolation of this model at the scale of the Western Pyrenees allows to propose other potential sources for major regional historical earthquakes.     

La vallée d'Ys : un paléoréseau hydrographique immergé en baie de Douarnenez (Finistère,France)

Interpretation of the recent high-resolution survey, CANADOU 2000, in the Bay of Douarnenez (Finistère, France) allowed us to restore the morphology of the substratum and the sedimentary filling of the bay. The Brioverian and Palaeozoic substratum reveals a well-defined network of incised valleys as results of successive emergence stages of the Bay during the Quaternary. Valleys join in a westward-widened mean valley, called Ys Valley. The present-day sedimentary fill of the bay of Douarnenez appears mainly controlled by the Holocene rise and the consecutive highstand. It comprises fluvial and estuarine deposits filling up incised valleys and marine sedimentation extending out of the incised valleys. To cite this article: G. Jouet et al., C. R. Geoscience 335 (2003).To cite this article: G. Jouet et al., C. R. Geoscience 335 (2003).     

The H N method for Milne problem with polarization

The H _N method, employed for studies in neutron transport theory, is used to establish numerical results basic to the vector equation describing the transfer of polarized light in a Rayleigh scattering atmosphere with true absorption. The method has been applied to the classical Milne problem. The exit distribution is defined as a series in powers of the zenith observation angle. The numerical results are computed and compared with exact values obtained using the exit distribution in terms of the H-matrix. The numerical results are in good agreement with previously published findings.