The match between climate services demands and Earth System Models supplies

Earth System Models (ESM) are key ingredients of many of the climate services that are currently being developed and delivered. However, ESMs have more applications than the provision of climate services, and similarly many climate services use more sources of information than ESMs. This discussion paper elaborates on dilemmas that are evident at the interface between ESMs and climate services, in particular: (a) purposes of the models versus service development, (b) gap between the spatial and temporal scales of the models versus the scales needed in applications, and (c) Tailoring climate model results to real-world applications. A continued and broad-minded dialogue between the ESM developers and climate services providers’ communities is needed to improve both the optimal use and direction of ESM development and climate service development. We put forward considerations to improve this dialogue between the communities developing ESMs and climate services, in order to increase the mutual benefit that enhanced understanding of prospects and limitations of ESMs and climate services will bring.This work and its contributors (B. van den Hurk, C. Hewitt, J. Bessembinder, F. Doblas-Reyes, R. Döscher) were funded by the Horizon 2020 Framework Programme of the European Union: Project ref. 689029 (Climateurope project). The co-author and editor of the journal states that she was not involved in the review process of the paper.Peer ReviewedPostprint (published version

Tropical and mid-latitude teleconnections interacting with the Indian summer monsoon rainfall: a theory-guided causal effect network approach

The alternation of active and break phases in Indian summer monsoon (ISM) rainfall at intraseasonal timescales characterizes each ISM season. Both tropical and mid-latitude drivers influence this intraseasonal ISM variability. The circumglobal teleconnection observed in boreal summer drives intraseasonal variability across the mid-latitudes, and a two-way interaction between the ISM and the circumglobal teleconnection pattern has been hypothesized. We use causal discovery algorithms to test the ISM circumglobal teleconnection hypothesis in a causal framework. A robust causal link from the circumglobal teleconnection pattern and the North Atlantic region to ISM rainfall is identified, and we estimate the normalized causal effect (CE) of this link to be about 0.2 (a 1 standard deviation shift in the circumglobal teleconnection causes a 0.2 standard deviation shift in the ISM rainfall 1 week later). The ISM rainfall feeds back on the circumglobal teleconnection pattern, however weakly. Moreover, we identify a negative feedback between strong updraft located over India and the Bay of Bengal and the ISM rainfall acting at a biweekly timescale, with enhanced ISM rainfall following strong updraft by 1 week. This mechanism is possibly related to the boreal summer intraseasonal oscillation. The updraft has the strongest CE of 0.5, while the Madden–Julian oscillation variability has a CE of 0.2–0.3. Our results show that most of the ISM variability on weekly timescales comes from these tropical drivers, though the mid-latitude teleconnection also exerts a substantial influence. Identifying these local and remote drivers paves the way for improved subseasonal forecasts

Effect of environmental humidity on the creep behavior of flax fiber-reinforced polymer composites

Flax fiber-reinforced polymer (FFRP) composites are emerging popular environmental-friendly construction materials. However, their significant creep properties have been a major concern for using FFRP in load-bearing structures. This article presents an investigation of the effect of environmental humidity on the creep behavior of the FFRP. Samples with flax fiber in 0°, 90°, and ± 45° were manufactured, respectively, by the vacuum infusion method. Accelerated creep tests were conducted on samples in different relative humidities (RH), and the results were analyzed by the time–temperature superposition principle (TTSP). It is found the creep development of samples with 0° and 90° fiber increases with the RH, and their 30-year total strain in 97% RH is about 10 times higher than that in 11% RH. The samples with ±45° fiber are found not obviously sensitive to the humidity change. The scanning electron microscope (SEM) check indicates the change in the fiber–matrix interface and cracks between microfibrils in a fiber bundle is the main reason for the change of creep behavior in high humidity. This study may benefit the design of structures made of natural fiber-reinforced polymer composites, especially for load-bearing structures working in high-humidity environments.</p

Should seasonal rainfall forecasts be used for flood preparedness?

In light of strong encouragement for disaster managers to use climate services for flood preparation, we question whether seasonal rainfall forecasts should indeed be used as indicators of the likelihood of flooding. Here, we investigate the primary drivers of flooding at the seasonal timescale across sub-Saharan Africa. Given the sparsity of hydrological observations, we input bias-corrected reanalysis rainfall into the Global Flood Awareness System to identify seasonal indicators of floodiness. Results demonstrate that in wet climates, even a perfect tercile forecast of seasonal total rainfall would provide little to no indication of the seasonal likelihood of flooding. The number of extreme events within a season shows the highest correlations with floodiness consistently across regions. Otherwise, results vary across climate regimes: floodiness in arid regions in Southern and Eastern Africa shows the strongest correlations with seasonal average soil moisture and seasonal total rainfall. Floodiness in wetter climates of West and Central Africa and Madagascar shows the strongest relationship with measures of the intensity of seasonal rainfall. Measures of rainfall patterns, such as the length of dry spells, are least related to seasonal floodiness across the continent. Ultimately, identifying the drivers of seasonal flooding can be used to improve forecast information for flood preparedness, and avoid misleading decision-makers

Living with sea-level rise in North-West Europe: Science-policy challenges across scales

Sea-level rise (SLR) confronts coastal societies and stakeholders with increasing hazards and coastal risks with large uncertainties associated to these changes. Adaptation to SLR requires societal and policy decision-making to consider these changing risks, which are in turn defined by socio-economic development objectives and the local societal context. Here, we review some of the key challenges facing governments, stakeholders and scientists in adapting to SLR, and key aspects of successful adaptation, by exploring different approaches to SLR and coastal adaptation planning in three western European countries, the Netherlands, Germany and the United Kingdom. Several common challenges of SLR adaptation emerge across the different settings, including the inherent uncertainty regarding future conditions, the significant social and socio-economic consequences, the consideration and distribution of (residual) risk over communities, and the long legacy of present-day decisions that affect future risk and management options supporting future generations. These challenges are addressed differently in the three countries, e.g. in the governance level at which adaptation is initiated, although common elements also emerge. One common emerging element is adaptive pathways planning, which entails dynamic decision-making that breaks uncertain decisions into manageable elements or steps over time, while keeping options for the future. Another common element is the development of effective local science-policy interfaces, as engagement of local decision-makers and citizens is essential to manage conflicting interests. Lastly, we find that social and communication sciences have great potential to support effective science-policy interfaces, e.g. though identifying societal tipping points. Yet, in decisions on SLR adaptation, insights from these fields are rarely used to date. We conclude that supporting science-policy interactions for adaptation decision-making at relevant (inter)national to local scales through tailored multi-disciplinary scientific assessments is an important way forward for SLR adaptation in Europe

Event-based storylines to address climate risk

The climate science community is challenged to adopt an actionable risk perspective, which is difficult to align with the traditional focus on model-based probabilistic climate change projections. Event-based storylines can provide a way out of this conundrum by putting emphasis on plausibility rather than probability. This links directly to common practices in disaster risk management using “stress-testing” for emergency preparedness based on events that are conditional on specific and plausible assumptions. Event-based storylines allow for conditional explanations, without full attribution of every causal factor, which is crucial when some aspects of the latter are complex and highly uncertain

Seasonal changes in a sandy beach fish assemblage at Canto Grande, Santa Catarina, South Brazil

Copyright © 2004 Coastal Education and Research Foundation (CERF).Neste trabalho realizaramse amostragens, com uma rede de praia, de modo a estudar a comunidade de peixes de substrato arenoso na enseada de Canto Grande, Santa Catarina, Brasil. As amostragens realizaramse em intervalos de 3 horas durante períodos de 24 h, numa base bimensal, entre Abril de 1996 e Fevereiro de 1997. Verificouse existir uma variação sazonal no número de espécies, densidade de peixes e biomassa, tendo os valores mais elevados ocorrido em Fevereiro (38 espécies, 257.6 peixes 1000 mˉ², 2286.4 g 1000 mˉ²). Recolheuse um total de 67 espécies, pertencentes a 56 géneros e a 33 famílias, sendo a comunidade dominada por sete espécies pertencentes a três famílias: Atherinella brasiliensis (Atherinidae); Brevoortia pectinata, Harengula clupeola e Sardinella brasiliensis (Clupeidae); Anchoviella lepidontostole, Cetengraulis edentulus e Lycengraulis grossidens (Engraulidae). Tanto a diversidade de espécies (H′) como a equitabilidade (J′) foram médias a elevadas ao longo do ano devido à baixa dominância. A maior mudança na estrutura da comunidade ocorreu entre os meses de Inverno (Julho e Agosto) e as outras estações. Nenhuma das espécies dominantes pode ser classificada como residente. Os principais predadores foram Pomatomus saltator (Inverno) e Trichiurus lepturus (Verão). A maior parte das espécies observadas foram ou peixes juvenis ou espécies pelágicas de pequeno tamanho e fortemente gregárias.ABSTRACT: A shallow-water fish assemblage, over a soft, sandy bottom, at Canto Grande, Santa Catarina, Brazil, was sampled with a beach seine. Sampling was undertaken at 3 h intervals over 24 h on a bimonthly basis between April 1996 and February 1997. There was a seasonal variation in the number of species, density of fishes and biomass with the highest values in February (38 species, 257.6 fish 1000 mˉ², 2286.4 g 1000 mˉ²). A total of 67 species, belonging to 56 genera and 33 families were collected and the assemblage was dominated by seven species belonging to three families: Atherinella brasiliensis (Atherinidae); Brevoortia pectinata, Harengula clupeola and Sardinella brasiliensis (Clupeidae); Anchoviella lepidontostole, Cetengraulis edentulus and Lycengraulis grossidens (Engraulidae). Species diversity (H′) and equitability (J′) were medium to high throughout the year due to the low dominance. The largest change in the assemblage structure occurred between winter months (July and August) and the other seasons. None of the dominant species can be classified as a resident. Main predators were Pomatomus saltator (winter) and Trichiurus lepturus (summer). Most of the species observed were either juvenile fish or small pelagic and strongly gregarious species