Search

Atmospheric rivers (ARs) in Antarctica cause strong intrusions of moisture and heat, resulting in intense precipitation events and elevated temperature levels. Here, we examine observed trends in the occurrence of temperature extremes and temperature anomalies at 17 science stations between mid-20th century and 2022 and look at their potential links to ARs. Annual daily maxima of temperature and temperature anomaly are considered extreme if they exceed the 99.7th percentile of the distribution of the variable. Using statistical theory on extreme values, the trend in 10-year return levels of these variables is analyzed. The occurrence of ARs is in turn retrieved using detection algorithms based on meridional integrated vapor transport (vIVT) and integrated water vapor (IWV) calculations. The results show a significant increase (p < 0.1) in the 10-year return levels of extreme temperatures for three stations on the Antarctic Peninsula, one in the eastern Weddell Sea region and two on the East Antarctic shelf. At the same time, over the East Antarctic Ice Sheet, a significant (p < 0.1) decrease in decadal return levels is observed at four stations. The relationship between these extremes and atmospheric rivers depends on the detection scheme used, but the results indicate that 7-54% of temperature extremes are associated with ARs, while 19-75% of extreme anomalies are associated with ARs. A strong increase in the frequency of atmospheric rivers is observed in the Antarctic Peninsula, which could explain the increase in temperature extremes in this region., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

This study explores the grain size seasonal variations on the East Antarctic Plateau, where dry metamorphism occurs, by using microwave radiometer observations from 2000 to 2022. Local meteorological conditions and large scale atmospheric phenomena have been considered in order to explain some peculiar changes of the snow grains. We find that the highest ice divide is the region with the largest grain size in the summer, mainly because the wind speed is low. Moreover, some extreme grain size values with respect to the average (over +3σ) were identified. In these cases, the ERA5 reanalysis revealed a high pressure blocking/ridge situation in the proximity of the onsets of the summer increase of the grain size, conveying the relatively warm and moist air coming from the mid latitudes, often associated with atmospheric rivers. If weak wind and low temperature conditions occur during the following weeks, dry snow metamorphism is facilitated, leading to grain growth. This determines anomalous high maximums of the snow grain size at the end of summer. These phenomena confirm the importance of moisture intrusion events in the East Antarctica and their impact on the physical properties of the ice sheet surface, with a co-occurrence of atmospheric rivers and seasonal changes of the grain size significant over 95 %.

Point d’étape sur le bouleversement en cours et la forme qu’il revêt..

Biodiversité, rendements agricoles, élevage, pêche… Rien n’est épargné par le changement climatique. Zoom sur deux effets en passe de devenir tristement familiers.

The West African Monsoon (WAM) brings precipitation in summer for around 80 million people from Senegal to Chad. Variability of the monsoon circulation has large impacts on Sahelian societies. However, future changes in Sahel precipitation are uncertain because of large differences between projections of various climate models. We show that uncertainty in Sahel precipitation change is associated with uncertainty at simulating future changes in surface air temperature over the northern Hemisphere, towards the end of the 21st century. We use a storyline approach, a statistical method, to construct scenarios of changes in Sahel precipitation, whose differences only depend on effects and uncertainty at simulating selected remote drivers of Sahel precipitation change. We select two remote drivers, the warming of the Atlantic Ocean and of the Euro-Mediterranean area. We show that uncertainty in changes in Atlantic Ocean and Euro-Mediterranean surface air temperature explains up to 50% of Sahel precipitation change uncertainty. We suggest that reducing uncertainty in the future warming of the North Atlantic and the Euro-Mediterranean areas would then allow reducing uncertainty in future changes in Sahel precipitation., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

This article offers some theoretical considerations on the literacy of Robert of Torigni (1106-1186), monk/prior of Le Bec (dép. Eure, cant. Brionne) and abbot of Mont-Saint-Michel (dép. Manche, cant. Pontorson), and one of the most celebrated historians of the twelfth century. In recent years, scholars have shown a renewed interest in Robert as an author and scribe, including his handwriting, his librarianship, his use of archival sources, and his working methods as a historian. At the same time, however, there is no study that approaches Robert’s relationship with the written word from a conceptual point of view. The present article attempts to fill this lacuna by revisiting Robert’s literary activities in the light of what is known amongst medievalists as the concept of “pragmatic literacy”. Cet article offre quelques réflexions théoriques autour de l’écriture de Robert de Torigni (1106-1186), moine / prieur du Bec-Hellouin (dép. Eure, cant. Brionne), abbé du Mont-Saint-Michel (dép. Manche, cant. Pontorson) et célèbre historien du XIIe siècle. Ces dernières années, les chercheurs se sont intéressés à Robert en tant qu’auteur et scribe en se penchant notamment sur son écriture, sa bibliothéconomie, son utilisation des archives et ses méthodes de travail. Cependant, aucune étude n’aborde la relation de Robert avec l’écrit d’un point de vue conceptuel. Cet article se propose donc de combler ces lacunes en réexaminant les activités littéraires de Robert à la lumière du concept d’« écriture pragmatique » bien connu des médiévistes. Questo articolo offre alcune riflessioni teoriche sulla scrittura di Roberto di Torigni (1106-1186), monaco/priore di Bec-Hellouin (Eure, Brionne), abate di Mont-Saint-Michel (Manche, Pontorson) e famoso storico del XII secolo. Negli ultimi anni, i ricercatori si sono interessati a Robert come autore e scriba, concentrandosi in particolare sulla sua scrittura, la sua biblioteconomia, il suo uso degli archivi e i suoi metodi di lavoro. Tuttavia, nessuno studio ha affrontato il rapporto di Robert con la parola scritta da un punto di vista concettuale. Questo articolo si propone quindi di colmare questa lacuna riesaminando le attività letterarie di Robert alla luce del concetto di “scrittura pragmatica” ben noto ai medievalisti. Dieser Aufsatz bietet einige theoretisch-methodische Erwägungen zum Schriftverständnis und zum Schriftgebrauch Roberts von Torigni (1106-1186), des Mönchs und Kloster-Priors von Le Bec (dép. Eure, cant. Brionne) und späteren Abts von Mont-Saint-Michel (dép. Manche, cant. Pontorson), der zu den bekanntesten Geschichtsschreibern des zwölften Jahrhunderts zählt. Jüngere Forschungen haben erneut Interesse an Robert gezeigt, insbesondere an seinen Funktionen als Autor, Schreiber/Kalligraph, Bibliothekar und Benutzer archivalischer Schriften, sowie an seinen Arbeitsmethoden als Historiker. Eine konzeptuelle Untersuchung zu Roberts Beziehung mit unterschiedlichen Gebrauchs- und Ausdrucksformen mittelalterlicher Schriftlichkeit ist hingegen bislang nicht versucht worden. Der vorliegende Aufsatz widmet sich diesem Desiderat, indem er Roberts Schrifttätigkeit erstmals konkret im Rahmen „pragmatischer Schriftlichkeit“ durchleuchtet.

This article offers some theoretical considerations on the literacy of Robert of Torigni (1106-1186), monk/prior of Le Bec (dép. Eure, cant. Brionne) and abbot of Mont-Saint-Michel (dép. Manche, cant. Pontorson), and one of the most celebrated historians of the twelfth century. In recent years, scholars have shown a renewed interest in Robert as an author and scribe, including his handwriting, his librarianship, his use of archival sources, and his working methods as a historian. At the same time, however, there is no study that approaches Robert’s relationship with the written word from a conceptual point of view. The present article attempts to fill this lacuna by revisiting Robert’s literary activities in the light of what is known amongst medievalists as the concept of “pragmatic literacy”.

[No Abstract]

15 pages; International audience; Reconstructing the spatial and temporal response of mountain glaciers to rapid climate change in the past provides access to the effects of current climate change. Yet, the spatial and temporal variability of past glacier fluctuations is not fully understood. In this study, we focus on the timing of glacier fluctuations in the European Alps during the Younger Dryas/Early Holocene (YD/EH) transition. In an effort to elucidate whether glacier fluctuations were synchronous during this period, we present a new chronology of the Alpine Talèfre glacier, based on 14 new 10Be ages of moraines and roches moutonnées. The retreat of Talèfre glacier was initiated during the mid-YD (~12.4 ka), then it experienced a gradual retreat punctuated by at least three oscillations until ∼11 ka before shrinking substantially within its Little Ice Age limits (13th−19th centuries). Comparison of our findings with published glacier chronologies in the Alpine region highlights broadly synchronous behaviour of glaciers across the Alps between 12 and 10 ka. The coeval glacier fluctuations at a regional scale suggest that common regional climate conditions had a major impact on Alpine glacier variations during the YD/EH transition. The similarity of glacier behaviour and independent temperature records in both the Alpine region and the northern high latitudes suggests a teleconnection between these regions, but differences in the amplitude of the mean annual temperature signals relative to summer temperature indicate pronounced changes in seasonality between the YD and the EH.

Der Vortrag befasst sich mit dem Neubau der von Wibald von Stablo in Corvey in Auftrag gegebenen Abtsresidenz. Im Vordergrund steht hierbei die Frage, ob die Schreibstube Wibalds, in welcher dieser nach zeitgenössischen Berichten Schriftstücke für den dienstlichen und auch den privaten Gebrauch verwahrte, im europäischen Vergleich für die Zeit des 12. Jahrhunderts als Sonderfall oder die Regel zu betrachten ist. Der Vortrag ist Teil eines größeren Forschungsprojektes zur Geschichtsschreibung mittelalterlicher Äbte.

This article is dedicated to Liesbeth van Houts, editor of the Gesta Normannorum ducum, generous mentor, colleague, and friend.This article offers an analysis, edition, and translation of the Brevis cronica compendiosa ducum Normannie, a historiographical account of the dukes of Normandy and their deeds, written at the turn of the fifteenth century by the Norman jurist and man of letters, Simon de Plumetot (1371–1443). Having all but escaped the attention of modern scholars, this study is the first to examine and publish the Brevis cronica. It not only demonstrates that the work is of greater importance than its rather scrappy form might at first suggest, but it also looks to place the text within the broader context of Simon's literary and bibliophilic practices and to determine its raison d’être. In doing so, it argues that the Brevis cronica was perhaps created as part of a much larger historiographical project, namely an extended chronicle of Normandy, written in the vernacular, the text of which is now lost. By exploring these important issues, the article sheds new light on a wide range of topics, from early humanist book collecting to the writing of history in France in the later Middle Ages.

Paris, Bibliothèque nationale de France, latin 2342 (hereafter MS Lat. 2342) is a codex that has long fascinated scholars, though precious little is known about the specific circumstances of its production . In its present form, the manuscript is a compendium of eleven Latin works (Appendix 1), over half of which are otherwise unattested and probably represent original compositions. Most of them were written by a single scribe, presumably the author himself. Many attempts have been made to identify this author/scribe, but all we know is that he was almost certainly a monk at the abbey of Le Bec in Normandy (dép. Eure, cant. Brionne) during the first half of the twelfth century, which is why he is commonly referred to as the Anonymus Beccensis . This article offers a fresh study of the composition and authorship of MS Lat. 2342 divided into three sections. The first section provides a holistic codicological and palaeographical discussion of MS Lat. 2342 which for the first time considers the entire book, rather than concentrating on individual segments. The second section builds on this discussion by developing a ‘profile’ of the Anonymus Beccensis that includes his education and the authorities he used and cited most frequently. The final section explores some intriguing similarities between this ‘profile’ and the life and career of one particular monk of Le Bec who – as I shall argue – presents a potential match for the person who wrote MS Lat. 2342. In preparing this study, I have benefited from consulting the manuscript both in situ and through the digital facsimile made available by «The Polonsky Foundation England and France Project: Manuscripts from the British Library and the Bibliothèque nationale de France, 700-1200».

This article provides the first detailed study of two medieval liturgical manuscripts from the Benedictine Abbey of Lambach, Upper Austria, kept today in the monastic Library and Archives of Downside Abbey in Stratton-on-the-Fosse, Somerset, UK. The new codicological, palaeographical and historical evidence presented in this study shows that both these manuscripts played a central part in the monastery’s liturgical life and routine during the later 12th century. The first part of the article provides a full codicological and palaeographical analysis of the two manuscripts, the first to appear in published form, while the second part offers a wider thematic study that contextualises the two codices and their contents within Lambach’s medieval liturgical and communal culture.

[No abstract]

The impact of the increase of greenhouse gases on Sahelian precipitation is very uncertain in both its\ud spatial pattern and magnitude. In particular, the relative importance of internal variability versus\ud external forcings depends on the time horizon considered in the climate projection. In this study we\ud address the respective roles of the internal climate variability versus external forcings on Sahelian\ud precipitation by using the data from the CESMLarge Ensemble Project,which consists of a 40\ud member ensemble performed with the CESM1-CAM5 coupled model for the period 1920–2100.\ud We show that CESM1-CAM5 is able to simulate the mean and interannual variability of Sahel\ud precipitation, and is representative of a CMIP5 ensemble of simulations (i.e. it simulates the same\ud pattern of precipitation change along with equivalent magnitude and seasonal cycle changes as the\ud CMIP5 ensemble mean). However, CESM1-CAM5 underestimates the long-term decadal variability\ud in Sahel precipitation. For short-term (2010–2049) and mid-term (2030–2069) projections the\ud simulated internal variability component is able to obscure the projected impact of the external\ud forcing. For long-term (2060–2099) projections external forcing induced change becomes stronger\ud than simulated internal variability. Precipitation changes are found to be more robust over the central\ud Sahel than over the western Sahel, where climate change effects struggle to emerge. Ten (thirty)\ud members are needed to separate the 10 year averaged forced response from climate internal variability\ud response in the western Sahel for a long-term (short-term) horizon. Over the central Sahel two\ud members (ten members) are needed for a long-term (short-term) horizon.

Trends in daily maximum (TX) and minimum (TN) temperatures and indices of warm extremes are studied in tropical North Africa, west of the eastern African highlands, from 1961 to 2014. The analysis is based on the concatenation and cross-checking of two observed databases. Due to the large number of missing entries (similar to 25%), a statistical infilling using probabilistic principal component analysis was applied. Averaged over 90 stations, the linear trends of annual mean TX and TN equal respectively +0.021 degrees C/yr and +0.028 degrees C/yr. The frequency of very hot days (TX > 35 degrees C) and tropical nights (TN> 20 degrees C), as well as the frequency of daily TX and TN above the 90th percentile (p90) ("warm days" and "warm nights"), roughly follows the variations of mean TX and TN, respectively. Heat spells of TX or TN> p90 are often short (usually 8 years) variations may be viewed as a regional-scale fingerprint of the global warming, with largest correlations in the tropical Atlantic and Indian basins, while the high-frequency (

International audience; Using daily rain-gauge records for Madagascar and nearby islands, this paper investigates rainfall intraseasonal variability at local and regional scales during the austral summer season (November–February), as well as the respective influences of recurrent convective regimes over the South-West Indian Ocean (SWIO) and the Madden-Julian Oscillation (MJO). Our results show a general consistency between local-scale rainfall variability in Madagascar and regional-scale features of climate variability. The influence of Tropical-Temperate Troughs in their mature phase and/or their easternmost locations is first underlined. The development of such systems over Southern Africa and the Mozambique Chanel can be considered as precursors for Malagasy wet spells, especially over the southern part of the island. Regional and local effects of the MJO are weaker on average, and only concern the northwest of the island and the north of the Mozambique Chanel. MJO and convective regimes are finally shown to explain distinct fractions of regional rainfall variability.