Everything Hits at Once: How Remote Rainfall Matters for the Prediction of the 2021 North American Heat Wave

In June 2021, Western North America experienced an intense heat wave with unprecedented temperatures and far-reaching socio-economic consequences. Anomalous rainfall in the West Pacific triggers a cascade of weather events across the Pacific, which build up a high-amplitude ridge over Canada and ultimately lead to the heat wave. We show that the response of the jet stream to diabatically enhanced ascending motion in extratropical cyclones represents a predictability barrier with regard to the heat wave magnitude. Therefore, probabilistic weather forecasts are only able to predict the extremity of the heat wave once the complex cascade of weather events is captured. Our results highlight the key role of the sequence of individual weather events in limiting the predictability of this extreme event. We therefore conclude that it is not sufficient to consider such rare events in isolation but it is essential to account for the whole cascade over different spatiotemporal scales

Dynamics of concurrent and sequential Central European and Scandinavian heatwaves

In both 2003 and 2018 a heatwave in Scandinavia in July was followed by a heatwave in Central Europe in August. Whereas the transition occurred abruptly in 2003, it was gradual in 2018 with a 12-day period of concurrent heatwaves in both regions. This study contrasts these two events in the context of a heatwave climatology to elucidate the dynamics of both concurrent and sequential heatwaves. Central European and, in particular, concurrent heatwaves are climatologically associated with weak pressure gradient (WPG) events over Central Europe, which indicate the absence of synoptic activity over this region. One synoptic pattern associated with such events is Scandinavian blocking. This pattern is at the same time conducive to heatwaves in Scandinavia, thereby providing a mechanism by which Scandinavian and Central European heatwaves can co-occur. Further, the association of WPG events with Scandinavian blocking constitutes a mechanism that allows heatwaves to grow beyond the perimeter of the synoptic system from which they emanated. A trajectory analysis of the source regions of the low-level air incorporated in the heatwaves indicates rapidly changing air mass sources throughout the heatwaves in both regions, but no recycling of heat from one heatwave to the other. This finding is line with a composite analysis indicating that transitions between Scandinavian and Central European heatwaves are merely a random coincidence of heatwave onset and decay

Warm conveyor belt activity over the Pacific: modulation by the Madden–Julian Oscillation and impact on tropical–extratropical teleconnections

Research in the last few decades has revealed that rapidly ascending airstreams in extratropical cyclones – so-called warm conveyor belts (WCBs) – play an important role in extratropical atmospheric dynamics. However on the subseasonal timescale, the modulation of their occurrence frequency, henceforth referred to as WCB activity, has so far received little attention. Also, it is not yet clear whether WCB activity may affect tropospheric teleconnection patterns, which constitute a source of predictability on this subseasonal timescale. Using reanalysis data, this study analyzes the modulation of WCB activity by the Madden–Julian Oscillation (MJO). A key finding is that WCB activity increases significantly over the western North Pacific when the convection of the MJO is located over the Indian Ocean. This increased WCB activity, which is stronger during La Niña conditions, is related to enhanced poleward moisture fluxes driven by the circulation of subtropical Rossby gyres associated with the MJO. In contrast, when the convection of the MJO is located over the western North Pacific, WCB activity increases significantly over the eastern North Pacific. This increase stems from a southward shift and eastward extension of the North Pacific jet stream. However, while these mean increases are significant, individual MJO events exhibit substantial variability, with some events even exhibiting anomalously low WCB activity. Individual events of the same MJO phase with anomalously low WCB activity over the North Pacific tend to be followed by the known canonical teleconnection patterns in the Atlantic–European region; i.e., the occurrence frequency of the positive phase of the North Atlantic Oscillation (NAO) is enhanced when convection of the MJO is located over the Indian Ocean and similarly for the negative phase of the NAO when MJO convection is over the western North Pacific. However, the canonical teleconnection patterns are modified when individual events of the same MJO phase are accompanied by anomalously high WCB activity over the North Pacific. In particular, the link between MJO and the negative phase of the NAO weakens considerably. Reanalysis data and experiments with an idealized general circulation model reveal that this is related to anomalous ridge building over western North America favored by enhanced WCB activity. Overall, our study highlights the potential role of WCBs in shaping tropical–extratropical teleconnection patterns and underlines the importance of representing them adequately in numerical weather prediction models in order to fully exploit the sources of predictability emerging from the tropics.</p

Measuring communication as a core outcome in aphasia trials: Results of the ROMA-2 international core outcome set development meeting

BACKGROUND: Evidence-based recommendations for a core outcome set (COS; minimum set of outcomes) for aphasia treatment research have been developed (the Research Outcome Measurement in Aphasia-ROMA, COS). Five recommended core outcome constructs: communication, language, quality of life, emotional well-being and patient-reported satisfaction/impact of treatment, were identified through three international consensus studies. Constructs were paired with outcome measurement instruments (OMIs) during an international consensus meeting (ROMA-1). Before the current study (ROMA-2), agreement had not been reached on OMIs for the constructs of communication or patient-reported satisfaction/impact of treatment. AIM: To establish consensus on a communication OMI for inclusion in the ROMA COS. METHODS & PROCEDURES: Research methods were based on recommendations from the Core Outcome Measures in Effectiveness Trials (COMET) Initiative. Participants with expertise in design and conduct of aphasia trials, measurement instrument development/testing and/or communication outcome measurement were recruited through an open call. Before the consensus meeting, participants agreed on a definition of communication, identified appropriate OMIs, extracted their measurement properties and established criteria for their quality assessment. During the consensus meeting they short-listed OMIs and participants without conflicts of interest voted on the two most highly ranked instruments. Consensus was defined a priori as agreement by ≥ 70% of participants. OUTCOMES & RESULTS: In total, 40 researchers from nine countries participated in ROMA-2 (including four facilitators and three-panel members who participated in pre-meeting activities only). A total of 20 OMIs were identified and evaluated. Eight short-listed communication measures were further evaluated for their measurement properties and ranked. Participants in the consensus meeting (n = 33) who did not have conflicts of interest (n = 29) voted on the top two ranked OMIs: The Scenario Test (TST) and the Communication Activities of Daily Living-3 (CADL-3). TST received 72% (n = 21) of 'yes' votes and the CADL-3 received 28% (n = 8) of 'yes' votes. CONCLUSIONS & IMPLICATIONS: Consensus was achieved that TST was the preferred communication OMI for inclusion in the ROMA COS. It is currently available in the original Dutch version and has been adapted into English, German and Greek. Further consideration must be given to the best way to measure communication in people with mild aphasia. Development of a patient-reported measure for satisfaction with/impact of treatment and multilingual versions of all OMIs of the COS is still required. Implementation of the ROMA COS would improve research outcome measurement and the quality, relevance, transparency, replicability and efficiency of aphasia treatment research. WHAT THIS PAPER ADDS: What is already known on this subject International consensus has been reached on five core constructs to be routinely measured in aphasia treatment studies. International consensus has also been established for OMIs for the three constructs of language, quality of life and emotional well-being. Before this study, OMIs for the constructs of communication and patient-reported satisfaction/impact of treatment were not established. What this paper adds to existing knowledge We gained international consensus on an OMI for the construct of communication. TST is recommended for inclusion in the ROMA COS for routine use in aphasia treatment research. What are the potential or actual clinical implications of this work? The ROMA COS recommends OMIs for a minimum set of outcomes for adults with post-stroke aphasia within phases I-IV aphasia treatment research. Although not intended for clinical use, clinicians may employ the instruments of the ROMA COS, considering the quality of their measurement properties. The systematic inclusion of a measure of communication, such as TST, in clinical practice could ultimately support the implementation of research evidence and best practices

Les nouvelles technologies de la communication, les jeunes et leur socialisa-tion : pourquoi est-ce si compliqué ?

audience: professional, student, popularizationLe succès du smartphone n'est pas le seul résultat d’une stratégie commerciale, de promotions attractives lancées par les opérateurs de téléphonie mobile… Il ne peut pas non plus être réduit à une forme de consommation ostentatoire. A l'instar d’autres innovations technologiques, il s'est installé de façon durable dans notre quotidien. Pourquoi ? Répondre à cette question, c’est envisager la « fonction » qu'une chose remplit. Si une chose n’a pas de « fonction », si elle n’a pas d’utilité, si on ne sait pas à quoi ça sert ou à quoi ça peut servir, il y a peu de chances qu’elle survive longtemps. La question du « à quoi ça sert » peut être transformée en une autre question : quelle est la contribution de cette chose à l’organisation des sociétés, compte tenu des préoccupations qui y dominent à un moment donné ? A quel(s) besoin(s) répond-elle