How does convective self-aggregation affect precipitation extremes?

2021 ◽  
Author(s):  
Nicolas Da Silva ◽  
Sara Shamekh ◽  
Caroline Muller ◽  
Benjamin Fildier
Keyword(s):  
Extreme Rainfall ◽  
Precipitation Extremes ◽  
Tropical Precipitation ◽  
Warming Climate ◽  
Free Region ◽  
Depth Analysis ◽  
The Tropics ◽  
The Impact ◽  
Self Aggregation ◽  
Convective Organization

<p>Convective organisation has been associated with extreme precipitation in the tropics. Here we investigate the impact of convective self-aggregation on extreme rainfall rates. We find that convective self-aggregation significantly increases precipitation extremes, for 3-hourly accumulations but also for instantaneous rates (+ 30 %). We show that this latter enhanced instantaneous precipitation is mainly due to the local increase in relative humidity which drives larger accretion efficiency and lower re-evaporation and thus a higher precipitation efficiency.</p><p>An in-depth analysis based on an adapted scaling of precipitation extremes, reveals that the dynamic contribution decreases (- 25 %) while the thermodynamic is slightly enhanced (+ 5 %) with convective aggregation, leading to lower condensation rates (- 20 %). When the atmosphere is more organized into a moist convecting region, and a dry convection-free region, deep convective updrafts are surrounded by a warmer environment which reduces convective instability and thus the dynamic contribution. The moister boundary-layer explains the positive thermodynamic contribution. The microphysic contribution is increased by + 50 % with aggregation. The latter is partly due to reduced evaporation of rain falling through a moister near-cloud environment (+ 30 %), but also to the associated larger accretion efficiency (+ 20 %).</p><p>Thus, the change of convective organization regimes in a warming climate could lead to a much more different evolution of tropical precipitation extremes than expected from thermodynamical considerations. Improved fundamental understanding of convective organization and its sensitivity to warming, as well as its impact on precipitation extremes, is hence crucial to achieve accurate rainfall projections in a warming climate.</p>

scholarly journals Response of precipitation extremes to warming: what have we learned from theory and idealized cloud-resolving simulations, and what remains to be learned?

2021 ◽  
Author(s):  
Caroline Muller ◽  
Takayabu Yukari
Keyword(s):  
Extreme Rainfall ◽  
Precipitation Extremes ◽  
Theoretical Expectation ◽  
Physical Processes ◽  
Considerable Uncertainty ◽  
Rainfall Prediction ◽  
The Past ◽  
Warming Climate ◽  
Mesoscale Convective ◽  
Convective Organization

<p><span>In this work, we review recent important advances in our understanding of the response of precipitation extremes to warming from theory and from idealized cloud-resolving simulations. A theoretical scaling for precipitation extremes has been proposed and refined in the past decades, allowing to address separately the contributions from the thermodynamics, the dynamics and the microphysics. Theoretical constraints, as well as remaining uncertainties, associated with each of these three contributions to precipitation extremes, will be discussed. Notably, although to leading order precipitation extremes seem to follow the thermodynamic theoretical expectation in idealized simulations, considerable uncertainty remains regarding the response of the dynamics and of the microphysics to warming, and considerable departure from this theoretical expectation is found in observations and in more realistic simulations. We also emphasize key outstanding questions, in particular the response of mesoscale convective organization to warming. Observations suggest that extreme rainfall often comes from organized system in very moist environments. Improved understanding of the physical processes behind convective organization is needed in order to achieve accurate extreme rainfall prediction in our current, and in a warming climate. </span></p>

scholarly journals Impact of the 2015/2016 El Niño on the terrestrial carbon cycle constrained by bottom-up and top-down approaches

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170304 ◽  
Author(s):  
Ana Bastos ◽  
Pierre Friedlingstein ◽  
Stephen Sitch ◽  
Chi Chen ◽  
Arnaud Mialon ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
El Niño ◽  
El Nino ◽  
Carbon Sink ◽  
Terrestrial Carbon ◽  
Fire Emissions ◽  
Terrestrial Carbon Cycle ◽  
Depth Analysis ◽  
The Tropics ◽  
The Impact

Evaluating the response of the land carbon sink to the anomalies in temperature and drought imposed by El Niño events provides insights into the present-day carbon cycle and its climate-driven variability. It is also a necessary step to build confidence in terrestrial ecosystems models' response to the warming and drying stresses expected in the future over many continents, and particularly in the tropics. Here we present an in-depth analysis of the response of the terrestrial carbon cycle to the 2015/2016 El Niño that imposed extreme warming and dry conditions in the tropics and other sensitive regions. First, we provide a synthesis of the spatio-temporal evolution of anomalies in net land–atmosphere CO 2 fluxes estimated by two in situ measurements based on atmospheric inversions and 16 land-surface models (LSMs) from TRENDYv6. Simulated changes in ecosystem productivity, decomposition rates and fire emissions are also investigated. Inversions and LSMs generally agree on the decrease and subsequent recovery of the land sink in response to the onset, peak and demise of El Niño conditions and point to the decreased strength of the land carbon sink: by 0.4–0.7 PgC yr −1 (inversions) and by 1.0 PgC yr −1 (LSMs) during 2015/2016. LSM simulations indicate that a decrease in productivity, rather than increase in respiration, dominated the net biome productivity anomalies in response to ENSO throughout the tropics, mainly associated with prolonged drought conditions. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

The Catholic Diaspora—Experiences of Evacuation

2018 ◽  
Author(s):  
Thomas Brodie
Keyword(s):  
Urban Areas ◽  
Religious Practice ◽  
Catholic Clergy ◽  
Profound Influence ◽  
The Social ◽  
Depth Analysis ◽  
Nazi Era ◽  
Mass Evacuation ◽  
The Impact ◽  
Pastoral Practice

This chapter analyses the impact exerted on the Catholic Church’s pastoral networks in Germany by the mass evacuation of laypeople from bombed urban areas as of 1941. Drawing on the voluminous correspondence of priests and curates despatched from the Rhineland and Westphalia to Saxony, Thuringia, Silesia, Austria, and elsewhere to minister to Catholic evacuees, this chapter provides in-depth analysis of the social and cultural histories of religious practice in wartime Germany. It demonstrates that the evacuation of laypeople—a topic long neglected within histories of wartime religious practice—exerted a profound influence on pastoral practice by the years 1943–5, placing unprecedented pressures on the Catholic clergy of the dioceses central to this study (Aachen, Cologne and Münster). This chapter therefore also casts new light on regionalism in Germany during the Nazi era.

scholarly journals Decreased Medical Care During the COVID-19 Pandemic – A Comprehensive Analysis of Radiological Examinations

2021 ◽  
Author(s):  
Annette Aigner ◽  
Bernd Hamm ◽  
Florian Nima Fleckenstein ◽  
Tazio Maleitzke ◽  
Georg Böning ◽  
...  
Keyword(s):  
Medical Care ◽  
Control Period ◽  
Surrogate Marker ◽  
Medical Specialty ◽  
Case Volume ◽  
Medical Specialties ◽  
Key Points ◽  
Depth Analysis ◽  
The Impact ◽  
Radiological Examinations

Objectives As a cross-section discipline within the hospital infrastructure, radiological departments might be able to provide important information regarding the impact of the COVID-19 pandemic on healthcare. The goal of this study was to quantify changes in medical care during the first wave of the pandemic using radiological examinations as a comprehensive surrogate marker and to determine potential future workload. Methods A retrospective analysis of all radiological examinations during the first wave of the pandemic was performed. The number of examinations was compared to time-matched control periods. Furthermore, an in-depth analysis of radiological examinations attributed to various medical specialties was conducted and postponed examinations were extrapolated to calculate additional workload in the near future. Results A total of 596,760 examinations were analyzed. Overall case volumes decreased by an average of 41 % during the shutdown compared to the control period. The most affected radiological modalities were sonography (–54 %), X-ray (–47 %) followed by MRI (–42 %). The most affected medical specialty was trauma and orthopedics (–60 % case volume) followed by general surgery (–49 %). Examination numbers increased during the post-shutdown period leading to a predicted additional workload of up to 22 %. Conclusion This study shows a marked decrease in radiological examinations in total and among several core medical specialties, indicating a significant reduction in medical care during the first COVID-19 shutdown. Key Points: Citation Format

scholarly journals Ontogenetic shift in the trophic role of the invasive killer shrimp Dikerogammarus villosus: a stable isotope study

2021 ◽  
Author(s):  
Francesco Mancini ◽  
Raffaele De Giorgi ◽  
Alessandro Ludovisi ◽  
Salvatrice Vizzini ◽  
Giorgio Mancinelli
Keyword(s):  
Dietary Habits ◽  
Trophic Position ◽  
Ecological Impact ◽  
Central Italy ◽  
Local Conditions ◽  
Dikerogammarus Villosus ◽  
Isotopic Signatures ◽  
Depth Analysis ◽  
Stable Isotope Study ◽  
The Impact

AbstractThe introduction of the amphipod Dikerogammarus villosus in European fresh waters is to date recognized as a threat to the integrity of invaded communities. Predation by D. villosus on native benthic invertebrates is assumed as the key determinant of its ecological impact, yet available information describe the species as a primary consumer as well as a carnivore depending on local conditions. Here, we assessed the trophic position (TP) of D. villosus in Lake Trasimeno, a recently invaded lentic system in central Italy, using the CN isotopic signatures of individuals captured in winter spanning two orders of magnitude in body size. TP estimations were compared with those characterizing the native amphipod Echinogammarus veneris and other representative invertebrate predators. On average, D. villosus showed a trophic position higher than E. veneris, and comparable with that of odonate nymphs. An in-depth analysis revealed that large-sized individuals had a trophic position of 3.07, higher than odonates and close to that of the hirudinean predator Erpobdella octoculata, while small-sized specimens had a trophic position of 2.57, similar to that of E. veneris (2.41). These findings indicate that size-related ontogenetic shifts in dietary habits may per se vary the nature of the interaction between Dikerogammarus villosus and native invertebrates from competition to predation. Information collated from published isotopic studies corroborated the generality of our results. We conclude that intra-specific trophic flexibility may potentially amplify and make more multifaceted the impact of the species on other invertebrate species in invaded food webs.

scholarly journals Post-Processing Techniques for the Improvement of Liposome Stability

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1023
Author(s):  
Ji Young Yu ◽  
Piyanan Chuesiang ◽  
Gye Hwa Shin ◽  
Hyun Jin Park
Keyword(s):  
Freeze Drying ◽  
Protective Agent ◽  
Post Processing ◽  
Additional Process ◽  
Spray Freeze Drying ◽  
The Stability ◽  
Processing Techniques ◽  
The Impact ◽  
Self Aggregation ◽  
Liposome Stability

Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.

scholarly journals Dipole patterns in tropical precipitation were pervasive across landmasses throughout Marine Isotope Stage 5

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katrina Nilsson-Kerr ◽  
Pallavi Anand ◽  
Philip B. Holden ◽  
Steven C. Clemens ◽  
Melanie J. Leng
Keyword(s):  
Large Scale ◽  
Marine Isotope Stage ◽  
Convergence Zone ◽  
Inter Tropical Convergence Zone ◽  
Tropical Regions ◽  
Tropical Precipitation ◽  
Rainfall Patterns ◽  
Marine Isotope Stage 5 ◽  
Climate Cooling ◽  
The Tropics

AbstractMost of Earth’s rain falls in the tropics, often in highly seasonal monsoon rains, which are thought to be coupled to the inter-hemispheric migrations of the Inter-Tropical Convergence Zone in response to the seasonal cycle of insolation. Yet characterization of tropical rainfall behaviour in the geologic past is poor. Here we combine new and existing hydroclimate records from six large-scale tropical regions with fully independent model-based rainfall reconstructions across the last interval of sustained warmth and ensuing climate cooling between 130 to 70 thousand years ago (Marine Isotope Stage 5). Our data-model approach reveals large-scale heterogeneous rainfall patterns in response to changes in climate. We note pervasive dipole-like tropical precipitation patterns, as well as different loci of precipitation throughout Marine Isotope Stage 5 than recorded in the Holocene. These rainfall patterns cannot be solely attributed to meridional shifts in the Inter-Tropical Convergence Zone.

scholarly journals Corporate Social Responsibility Disclosure: Responding to Investors’ Criticism on Social Media

2021 ◽  
Vol 18 (14) ◽  
pp. 7396
Author(s):  
Yuming Zhang ◽  
Fan Yang
Keyword(s):  
Social Media ◽  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Social Issues ◽  
Media Criticism ◽  
Csr Communication ◽  
Depth Analysis ◽  
Csr Disclosure ◽  
Corporate Social ◽  
The Impact

Companies use corporate social responsibility (CSR) disclosures to communicate their social and environmental policies, practices, and performance to stakeholders. Although the determinants and outcomes of CSR activities are well understood, we know little about how companies use CSR communication to manage a crisis. The few relevant CSR studies have focused on the pressure on corporations exerted by governments, customers, the media, or the public. Although investors have a significant influence on firm value, this stakeholder group has been neglected in research on CSR disclosure. Grounded in legitimacy theory and agency theory, this study uses a sample of Chinese public companies listed on the Shanghai Stock Exchange to investigate CSR disclosure in response to social media criticism posted by investors. The empirical findings show that investors’ social media criticism not only motivates companies to disclose their CSR activities but also increases the substantiveness of their CSR reports, demonstrating that companies’ CSR communication in response to a crisis is substantive rather than merely symbolic. We also find that the impact of social media criticism on CSR disclosure is heterogeneous. Non-state-owned enterprises, companies in regions with high levels of environmental regulations, and companies in regions with local government concern about social issues are most likely to disclose CSR information and report substantive CSR activities. We provide an in-depth analysis of corporate CSR strategies for crisis management and show that crises initiated by investors on social media provide opportunities for corporations to improve their CSR engagement.

scholarly journals Assessment of Rainfall-Induced Landslide Distribution Based on Land Disturbance in Southern Taiwan

2021 ◽  
Vol 10 (4) ◽  
pp. 209
Author(s):  
Chih-Ming Tseng ◽  
Yie-Ruey Chen ◽  
Chwen-Ming Chang ◽  
Yung-Sheng Chue ◽  
Shun-Chieh Hsieh
Keyword(s):  
Satellite Image ◽  
Extreme Rainfall ◽  
Land Area ◽  
Rainfall Events ◽  
Land Disturbance ◽  
Bare Land ◽  
Southern Taiwan ◽  
The Impact ◽  
Landslide Distribution ◽  
The Relationship

This study explores the impact of rainfall on the followed-up landslides after a severe typhoon and the relationship between various rainfall events and the occurrence, scale, and regional characteristics of the landslides, including second landslides. Moreover, the influence of land disturbance was evaluated. The genetic adaptive neural network was used in combination with the texture analysis of the geographic information system for satellite image classification and interpretation to analyze land-use change and retrieve disaster records and surface information after five rainfall events from Typhoon Morakot (2009) to Typhoon Nanmadol (2011). The results revealed that except for extreme Morakot rains, the greater the degree of slope disturbance after rain, the larger the exposed slope. Extreme rainfall similar to Morakot strikes may have a greater impact on the bare land area than on slope disturbance. Moreover, the relationship between the bare land area and the index of land disturbance condition (ILDC) is positive, and the ratio of the bare land area to the quantity of bare land after each rainfall increases with the ILDC. With higher effective accumulative rainfall on the slope in the study area or greater slope disturbance, the landslide area at the second landslide point tended to increase.

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