The role of cloud diabatic processes in the life cycle of Atlantic-European weather regimes

2021 ◽  
Author(s):  
Christian M. Grams
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Multiple Scales ◽  
Weather Prediction ◽  
Time Lag ◽  
Conveyor Belt ◽  
Life Cycles ◽  
Weather Regimes ◽  
Diabatic Processes

<p>Weather regimes are quasi-stationary, persistent, and recurrent states of the large-scale extratropical circulation. In the Atlantic-European region these explain most of the atmospheric variability on sub-seasonal time scales. However, current numerical weather prediction (NWP) systems struggle in correctly predicting weather regime life cycles. Latent heat release in ascending air streams injects air into the upper troposphere, which might ultimately result in blocking. Such diabatic outflow is often linked to warm conveyor belt (WCB) activity and has been shown to be involved in upscale error growth up to the regime scale. This study systematically investigates the role of diabatic outflow in the life cycle of Atlantic-European weather regimes.</p><p>An extended definition of 7 year-round Atlantic-European weather regimes from 37 years of ERA-Interim reanalysis is used. This is based on an EOF analysis and k-means clustering of normalized low-pass-filtered 500hPa geopotential height anomalies. Furthermore an objective regime life cycle is derived. The role of cloud-diabatic processes in European weather regimes is assessed based on time lag analysis of WCB activity at specific life cycle stages.</p><p>Results indicate that the period prior to regime onset is characterized by important changes in location and frequency of WCB occurrence. Most importantly, prior to the onset of regimes characterized by blocking, WCB activity increases significantly upstream of the incipient blocking even before blocking is detectable and persists over the blocked region later. This suggests that diabatic WCB outflow helps to establish and maintain blocked regimes. Thus it is important to correctly represent cloud-diabatic processes in NWP models across multiple scales in order to predict the large-scale circulation accurately. Ongoing work now systematically investigates the representation of WCB activity in current NWP systems and how this relates to the forecast skill for weather regimes.</p>

scholarly journals Potential vorticity dynamics of life cycles of blocked weather regimes in the Euro-Atlantic region: A diagnostic framework

2021 ◽  
Author(s):  
Seraphine Hauser ◽  
Christian M. Grams ◽  
Michael Riemer ◽  
Peter Knippertz ◽  
Franziska Teubler
Keyword(s):  
Potential Vorticity ◽  
Large Scale ◽  
Climate Models ◽  
Numerical Models ◽  
Weather Prediction ◽  
Life Cycles ◽  
Forecast Errors ◽  
Atlantic Region ◽  
Weather Regimes ◽  
Medium Range

<p>Quasi-stationary, persistent, and recurrent states of the large-scale extratropical circulation, so-called weather regimes, characterize the atmospheric variability on sub-seasonal timescales of several days to a few weeks. Weather regimes featuring a blocking anticyclone are of particular interest due to their long lifetime and potential for high-impact weather. However, state-of-the-art numerical weather prediction and climate models struggle to correctly represent blocking life cycles, which results in large forecast errors at the medium-range to sub-seasonal timescale. Despite progress in recent years, we are still lacking a process-based conceptual understanding of blocked regime dynamics, which hinders a better representation of blocks in numerical models. In particular the relative contributions of dry and moist processes in the onset and maintenance of a block remain unclear.</p><p>Here we aim to revisit the dynamics of blocking in the Euro-Atlantic region. To this end we investigate the life cycles of blocked weather regimes from a potential vorticity (PV) perspective in ERA5 reanalysis data (from 1979 to present) from the European Centre for Medium-Range Weather Forecasts. We develop a diagnostic PV framework that allows the tracking of negative PV anomalies associated with blocked weather regimes. Complemented by piecewise PV-tendencies - separated into advective and diabatic PV tendencies - we are able to disentangle different physical processes affecting the amplitude evolution of negative PV anomalies associated with blocked regimes. Most importantly, this approach newly enables us to distinguish between the roles of dry and moist dynamics in the initiation and maintenance of blocked weather regimes in a common framework. A first application demonstrates the functionality of the developed PV framework and corroborates the importance of moist-diabatic processes in the initiation and maintenance of a block in a regime life cycle. </p>

Exploring the role of business relationships in start-ups’ life cycles

IMP Journal ◽  
2018 ◽  
Vol 12 (3) ◽  
pp. 519-543
Author(s):  
Chiara Cantù ◽  
Sepe Giorgia ◽  
Alessandra Tzannis
Keyword(s):  
Life Cycle ◽  
Secondary Data ◽  
Life Cycles ◽  
Business Relationships ◽  
Structured Interviews ◽  
Content Type ◽  
Strategic Resources ◽  
Start Up ◽  
Start Ups

Purpose Differently from previous works that focused on the entrepreneur and on his ability to manage social relationships, the purpose of this paper is to investigate the role of business relationships in the different stages of the life cycle of a start-up. Design/methodology/approach Since the paper aims to explore startups’ evolutionary phenomenon, it adopts a qualitative abductive methodology, presenting an in-depth study of two innovative Italian start-ups. The research is based on two steps. In the first one, the authors collected secondary data from start-ups’ reports and documents, financial indicators (when available) and processed them to understand their background. In the second one, the authors conducted ten semi-structured interviews, including face-to-face interviews, phone interviews and video conferences. Findings The paper presents a relationship-based life cycle model composed of four different stages, depending on the number and role of relationships developed. Indeed, since the beginning, start-ups adopt a relational approach and their evolution involves the shift from the focus on the entrepreneur to the centrality of a network approach based on interconnected relationships. The entering into a new stage of life cycle depends on relationships, mainly based on connected actors and resources shared and combined. Even if a key role is assumed by technology, the main resource is identified in the knowledge concerning the customer/user’s needs that require marketing competencies, human resources, relational capabilities. Thus, the shift from one stage to the next in the start-up’s life cycle is possible thanks to a parallel shift from a focus on the activities to a focus on those strategic and heterogeneous actors that ensure activities. Originality/value In a traditional perspective, the start-up’s life cycle depends on activities, financial resources and revenues, as stated by previous life cycle models. In a different perspective, as depicted in our analysis, the evolution of a start-up depends on the portfolio of their business relationships. The role of business relationships is hence to facilitate the interconnections within specialized key actors, which allow start-ups to access strategic resources. These resources are essential in order to develop the activities that characterize the specific stage of the life cycle.

scholarly journals CHNS Modeling for Study and Management of Human–Water Interactions at Multiple Scales

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1699 ◽  
Author(s):  
Kumaraswamy Ponnambalam ◽  
S. Jamshid Mousavi
Keyword(s):  
Large Scale ◽  
Multiple Scales ◽  
Water Cycle ◽  
Integrated Water Resources Management ◽  
Natural Systems ◽  
Institutional Issues ◽  
And Control ◽  
The Impact ◽  
Global Hydrology

This paper presents basic definitions and challenges/opportunities from different perspectives to study and control water cycle impacts on society and vice versa. The wider and increased interactions and their consequences such as global warming and climate change, and the role of complex institutional- and governance-related socioeconomic-environmental issues bring forth new challenges. Hydrology and integrated water resources management (IWRM from the viewpoint of an engineering planner) do not exclude in their scopes the study of the impact of changes in global hydrology from societal actions and their feedback effects on the local/global hydrology. However, it is useful to have unique emphasis through specialized fields such as hydrosociology (including the society in planning water projects, from the viewpoint of the humanities) and sociohydrology (recognizing the large-scale impacts society has on hydrology, from the viewpoint of science). Global hydrological models have been developed for large-scale hydrology with few parameters to calibrate at local scale, and integrated assessment models have been developed for multiple sectors including water. It is important not to do these studies with a silo mindset, as problems in water and society require highly interdisciplinary skills, but flexibility and acceptance of diverse views will progress these studies and their usefulness to society. To deal with complexities in water and society, systems modeling is likely the only practical approach and is the viewpoint of researchers using coupled human–natural systems (CHNS) models. The focus and the novelty in this paper is to clarify some of these challenges faced in CHNS modeling, such as spatiotemporal scale variations, scaling issues, institutional issues, and suggestions for appropriate mathematical tools for dealing with these issues.

scholarly journals On the Co-Occurrence of Warm Conveyor Belt Outflows and PV Streamers*

2014 ◽  
Vol 71 (10) ◽  
pp. 3668-3673 ◽  
Author(s):  
Erica Madonna ◽  
Sebastian Limbach ◽  
Christine Aebi ◽  
Hanna Joos ◽  
Heini Wernli ◽  
...  
Keyword(s):  
Life Cycle ◽  
Three Dimensional ◽  
Conveyor Belt ◽  
Rossby Wave Breaking ◽  
Weather Forecasts ◽  
Three Dimensional Objects ◽  
The North ◽  
Conveyor Belts ◽  
Diabatic Processes ◽  
Warm Conveyor Belts

Abstract The co-occurrence of warm conveyor belts (WCBs), strongly ascending moist airstreams in extratropical cyclones, and stratospheric potential vorticity (PV) streamers, indicators for breaking Rossby waves on the tropopause, is investigated for a 21-yr period in the Northern Hemisphere using Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) data. WCB outflows and PV streamers are respectively identified as two- and three-dimensional objects and tracked during their life cycle. PV streamers are more frequent than WCB outflows and nearly 15% of all PV streamers co-occur with WCBs during their life cycle, whereas about 60% of all WCB outflows co-occur with PV streamers. Co-occurrences are most frequent over the North Atlantic and North Pacific in spring and winter. WCB outflows are often located upstream of the PV streamers and form earlier, indicating the importance of diabatic processes for downstream Rossby wave breaking. Less frequently, PV streamers occur first, leading to the formation of new WCBs.

scholarly journals Smartphone and Tablet Application (App) Life Cycle Characterization via Apple App Store Rank

2020 ◽  
Vol 4 (1) ◽  
pp. 44-67
Author(s):  
Han Jia ◽  
Chun Guo ◽  
Xiaozhong Liu
Keyword(s):  
Life Cycle ◽  
Least Squares ◽  
Product Life Cycle ◽  
Large Scale ◽  
Ordinary Least Squares ◽  
Heterogeneous Data ◽  
Life Cycles ◽  
Volume Data ◽  
App Store ◽  
Management Domain

AbstractWith the rapid growth of the smartphone and tablet market, mobile application (App) industry that provides a variety of functional devices is also growing at a striking speed. Product life cycle (PLC) theory, which has a long history, has been applied to a great number of industries and products and is widely used in the management domain. In this study, we apply classical PLC theory to mobile Apps on Apple smartphone and tablet devices (Apple App Store). Instead of trying to utilize often-unavailable sales or download volume data, we use open-access App daily download rankings as an indicator to characterize the normalized dynamic market popularity of an App. We also use this ranking information to generate an App life cycle model. By using this model, we compare paid and free Apps from 20 different categories. Our results show that Apps across various categories have different kinds of life cycles and exhibit various unique and unpredictable characteristics. Furthermore, as large-scale heterogeneous data (e.g., user App ratings, App hardware/software requirements, or App version updates) become available and are attached to each target App, an important contribution of this paper is that we perform in-depth studies to explore how such data correlate and affect the App life cycle. Using different regression techniques (i.e., logistic, ordinary least squares, and partial least squares), we built different models to investigate these relationships. The results indicate that some explicit and latent independent variables are more important than others for the characterization of App life cycle. In addition, we find that life cycle analysis for different App categories requires different tailored regression models, confirming that inner-category App life cycles are more predictable and comparable than App life cycles across different categories.

Tetractinomyxon stages genetically consistent withSphaerospora dicentrarchi(Myxozoa: Sphaerosporidae) found inCapitellasp. (Polychaeta: Capitellidae) suggest potential role of marine polychaetes in parasite's life cycle

Parasitology ◽  
2016 ◽  
Vol 143 (8) ◽  
pp. 1067-1073 ◽  
Author(s):  
LUIS F. RANGEL ◽  
RICARDO CASTRO ◽  
SÓNIA ROCHA ◽  
RICARDO SEVERINO ◽  
GRAÇA CASAL ◽  
...  
Keyword(s):  
Life Cycle ◽  
Dna Sequences ◽  
Dicentrarchus Labrax ◽  
18S Rrna Gene ◽  
Life Cycles ◽  
Fish Farm ◽  
Rrna Gene ◽  
Commercial Fish ◽  
European Seabass

SUMMARYKnown life cycles of myxosporean parasites have two hosts, but very few life cycles have been disclosed, especially in the marine environment.Sphaerospora dicentrarchiSitjà-Bobadilla and Álvarez-Pellitero, 1992 is a systemic parasite from the European seabass,Dicentrarchus labrax(Linnaeus, 1758), a highly valuable commercial fish. It affects its health, leading to aquaculture production losses. During 2013 and 2014, an actinospore survey was conducted in a total of 5942 annelids collected from a fish farm in Algarve and from the Aveiro Estuary, in Portugal. A new tetractinomyxon actinospore was found in a capitellid polychaete, belonging to the generaCapitellacollected at the fish farm. The tetractinomyxons were pyriform measuring 11·1 ± 0·7µm in length and 7·2 ± 0·4µm in width, and presented three rounded polar capsules measuring 2·4 ± 0·3µm in diameter. The molecular analysis of the 18S rRNA gene sequences from the tetractinomyxons revealed a similarity of 100% with the DNA sequences deposited in the GenBank fromS. dicentrarchimyxospores collected from the European seabass and the spotted seabass in the same fish farm and 99·9% similarity with the DNA sequence obtained from the myxospores found infecting the European seabass in the Aveiro Estuary. Therefore, the new tetractinomyxons are inferred to represent the actinospore phase of theS. dicentrarchilife cycle.

Phenology, behavior, and host-relations of Dermacentor andersoni Stiles in outdoor "rodentaria," and in nature

1968 ◽  
Vol 46 (4) ◽  
pp. 677-689 ◽  
Author(s):  
P. R. Wilkinson
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Soil Surface ◽  
Life Cycles ◽  
Unit Weight ◽  
First Year ◽  
Marmota Flaviventris ◽  
New Information ◽  
Approximate Order ◽  
Soil Temperatures

Artificial tick foci or "rodentaria", infested with ovipositing females or larvae, have furnished new information on D. andersoni biology, and a means of mass production of adults for acaricide and other tests. Both a 1-year and a 2-year life cycle were observed, depending on the date the larvae emerged or were put out. Each year, adult ticks wandered near the soil surface in the fall but did not seek hosts or climb up to questing positions until spring. A tendency for the adult ticks to congregate southwards of the point of dropping of the engorged nymphs was discernible.In a large-scale rodentarium involving 24 runways, with four replicates of each of six species of rodents, by far the largest number of adult ticks was produced by Marmota flaviventris, but on a tick per unit weight of rodent basis, this species was low in the approximate order calculated.Adult ticks were ready to feed in mid-December in one trial, but they were inactive in the rodentarium because soil temperatures under the snow were usually about 0 °C, and activity does not begin until about 5 °C. The cycles observed in the rodentaria and the field indicate that both 1- and 2-year life cycles occur in southern British Columbia at an altitude of about 1000 ft. At higher altitudes and latitudes, a 3-year life cycle with overwintering larvae may occur. About 10% of the ticks marked in their first year of activity in 1964 were active the next spring.Female ticks from both 1-year and 2-year cycles were capable of paralyzing sheep.

scholarly journals Grappling with uncertainties in physical climate impact projections of water resources

2020 ◽  
Vol 163 (3) ◽  
pp. 1379-1397 ◽  
Author(s):  
Rutger Dankers ◽  
Zbigniew W. Kundzewicz
Keyword(s):  
Large Scale ◽  
Weather Prediction ◽  
Global Scale ◽  
Climate Impact ◽  
Climate Modelling ◽  
Large Uncertainty ◽  
Sources Of Uncertainty ◽  
Hydrological Extremes ◽  
Model Ensembles

AbstractThis paper reviews the sources of uncertainty in physical climate impact assessments. It draws on examples from related fields such as climate modelling and numerical weather prediction in discussing how to interpret the results of multi-model ensembles and the role of model evaluation. Using large-scale, multi-model simulations of hydrological extremes as an example, we demonstrate how large uncertainty at the local scale does not preclude more robust conclusions at the global scale. Finally, some recommendations are made: climate impact studies should be clear about the questions they want to address, transparent about the uncertainties involved, and honest about the assumptions being made.

Parasite life-cycle studies: a plea to resurrect an old parasitological tradition

2017 ◽  
Vol 91 (6) ◽  
pp. 647-656 ◽  
Author(s):  
I. Blasco-Costa ◽  
R. Poulin
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Integrative Taxonomy ◽  
Life Cycles ◽  
Intermediate Hosts ◽  
Parasite Life Cycle ◽  
Quantitative Evidence ◽  
Research Areas ◽  
Food Web Ecology ◽  
And Control

AbstractMany helminth taxa have complex life cycles, involving different life stages infecting different host species in a particular order to complete a single generation. Although the broad outlines of these cycles are known for any higher taxon, the details (morphology and biology of juvenile stages, specific identity of intermediate hosts) are generally unknown for particular species. In this review, we first provide quantitative evidence that although new helminth species are described annually at an increasing rate, the parallel effort to elucidate life cycles has become disproportionately smaller over time. We then review the use of morphological matching, experimental infections and genetic matching as approaches to elucidate helminth life cycles. Next we discuss the various research areas or disciplines that could benefit from a solid knowledge of particular life cycles, including integrative taxonomy, the study of parasite evolution, food-web ecology, and the management and control of parasitic diseases. Finally, we end by proposing changes to the requirements for new species descriptions and further large-scale attempts to genetically match adult and juvenile helminth stages in regional faunas, as part of a plea to parasitologists to bring parasite life-cycle studies back into mainstream research.

scholarly journals ICTIOFAUNA DE POÇAS DE MARÉ EM TERRAÇOS CONSOLIDADOS DO LITORAL AMAZÔNICO BRASILEIRO

2021 ◽  
Vol 25 (04) ◽  
pp. 880-888
Author(s):  
Rayane Gonçalves Aguiar ◽  
◽  
Erick Cristofore Guimarães ◽  
Pâmella Silva de Brito ◽  
Felipe Polivanov Ottoni ◽  
...  
Keyword(s):  
Life Cycle ◽  
Brazilian Amazon ◽  
Life Cycles ◽  
Main Role ◽  
Physiological Plasticity ◽  
Biodiversity Knowledge ◽  
Tidal Pools ◽  
Species Being ◽  
Intertidal Fishes

As poças de maré são formadas pelo represamento de massas d’água durante a vazante e a sua troca ocorre ao longo de cada ciclo de marés, configurando em um ambiente explorado por várias espécies. A ictiofauna é um componente das poças de maré, algumas espécies são totalmente adaptadas (e.g. plasticidade fisológica, tamanho reduzido) e seu ciclo de vida ocorre apenas nas poças de maré. Contudo, muitas espécies utilizam as poças de maré em algumas fases do ciclo de vida para fins de alimentação, refúgio e reprodução. Considerando que os inventários são fundamentais para o conhecimento da biodiversidade, nosso estudo investigou a assembleia de peixes em poças de marés da Praia do Araçagy no período de outubro de 2016 a abril de 2017. No total, nós registramos 409 exemplares, pertencendo a 13 espécies, distribuídas em 11 famílias e sete ordens. Espécies residentes e estuarinas de importância comercial foram dominantes. INTERTIDAL FISHES OF THE CEMENTED TERRACES FROM BRAZILIAN AMAZON COAST: Tidal pools are formed by the damming of marine water during an ebb tide and their exchange occurs along each tidal cycle, configuring an environment explored by several species. The ichthyofauna is one of the components of the tide pools, with some species being fully adapted (e. g. physiological plasticity, reduced size) and their life cycles occuring uniquely on this environment. However, most species use tide pools at some stage of their life cycle for feeding, refuge and reproduction. Considering the main role of faunal inventories for the increase in biodiversity knowledge, this study investigates the fish assemblage in tide pools at Praia do Araçagy from October 2016 to April 2017. In total, were recorded 409 specimens belonging to 13 species, distributed in 11 families and seven orders. Resident and estuarine species with commercial importance were dominant.

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