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Radiative effect of two contrail cirrus outbreaks over Western Europe estimated using geostationary satellite observations and radiative transfer calculations
Get PDFEstimation of the perturbation to the Earth’s energy budget by contrail outbreaks is required for estimating the climate impact of aviation and verifying the climate benefits of proposed contrail avoidance strategies such as aircraft rerouting. Here we identified two successive large-scale
contrail outbreaks developing in clear-sky conditions in geostationary and polar-orbiting satellite infrared images of Western Europe lasting from 22 to 23 June 2020. Their hourly cloud radiative effect, obtained using geostationary satellite cloud retrievals and radiative transfer calculations, is negative or weakly positive during daytime and positive during nighttime. The cumulative energy
forcing of the two outbreaks is 7 PJ and –8.5 PJ, with uncertainties of 3 PJ, stemming each from approximately 15-20 flights over periods of 19 and 7 hours, respectively. This study suggests that an automated quantification of contrail outbreak radiative effect is possible, at least for contrails forming in clear sky conditions
Distribution and morphology of non-persistent and persistent contrail formation areas in ERA5
No full textThe contrail formation potential as well as its temporal and spatial distribution are estimated using meteorological
conditions of temperature and relative humidity from the ERA5 re-analysis provided by the European Centre for Medium-
Range Weather Forecasts. Contrail formation is estimated with the Schmidt–Appleman criterion (SAc), solely considering thermodynamic effects. The focus is on a region ranging from Eastern United States to central Europe. Around 18,000 flight trajectories from the In-service Aircraft for a Global Observing System (IAGOS) are used as a representative subset of transatlantic, commercial flights. The typical crossing distance through a contrail-prone area is determined based on IAGOS measurements of temperature T and relative humidity r, then based on co-located ERA5 simulations of the same quantities. Differences in spatial resolution between IAGOS and ERA5 are addressed from an aircraft-centered perspective, using one kilometer segments, and a model-centered perspective, using 19 km flight sections. Using the aircraft centered approach, 50 % of the
crossings of persistent contrail (PC) regions based on IAGOS are shorter than 9 km, while in ERA5 the median is 155 km.
Time-averaged IAGOS data lead to a median crossing length of 66 km. The difference between the two data sets are attributed to the higher variability of r in IAGOS compared to ERA5. The model-centered approach yields similar results, but typical crossing lengths are larger by only up to 10 %. Binary masks of PC formation are created by applying the SAc on the twodimensional fields of T and r from ERA5. In a second step the morphology of PC regions is also assessed. Half of the PC regions in ERA5 are found to be smaller than ≈35000 km2 (at 200 hPa) and the median of the maximum dimension is shorter than 760 km (at 200 hPa). Furthermore, PC regions tend to be of near-circular shape with a tendency to a slight oval shape and a preferred alignment along the dominant westerly flow. Seasonal, vertical distributions of PC formation potential P are characterized by a maximum between 250 and 200 hPa. P is subject to seasonal variations with a maximum in magnitude and extension during the winter months and a minimum during summer. The horizontal distribution of PC regions suggests that PC regions are likely to appear in the same location on adjacent pressure levels. Climatologies of T, r, wind speed U, and resulting PC formation potential are calculated to identify the constraining effects of T and r on P. PC formation is primarily limited by too warm conditions below and too dry conditions above the formation region. The distribution of PCs is slanted towards lower altitudes from 30◦N to 70◦N, following lines of constant T and r. For an observed co-location of high U and P it remains unclear whether PC formation and the jet stream are favored by the same meteorological conditions or if the jet stream itself favors PC occurrence. This analysis suggests that some PC regions will be difficult to avoid by rerouting aircraft because of their large vertical and horizontal extents
Ultra-wideband-based real-time positioning with cascaded wireless clock synchronization method
Get PDFPositioning services are often required in industrial and public applications. The requirements for positioning systems include sufficient positioning accuracy, appropriate anchor deployment in complex scenarios, stability, and precise5 clock synchronization between anchors. Therefore, algorithms designed for single-room and simple laboratory scenarios are not suitable. To address these challenges, this article proposes a comprehensive solution that combines ultra-wideband (UWB) technology, Time Difference of Arrival (TDoA)-based positioning, and a cascaded wireless clock synchronization (CWCS) algo11rithm. First, we introduce the CWCS algorithm. Second, we discuss the control algorithm for transmitting clock calibration packets (CCP) through wireless broadcast. Finally, we define the Time-of-Arrival selection strategy for TDoA calculation. For multiroom scenarios, we present a positioning boundary optimization method based on received signal strength power and the first path power. This method performs well in real-world experiments
Newfoundland cod and English piracy in the early seventeenth century
Get PDFNewfoundland’s cod fisheries were a vital resource in the development and sustenance of Europe’s early modern maritime economies. As the fisheries preyed on cod, they in turn were preyed upon by a new threat in the form of pirates. The pattern of piracy in Newfoundland in the first decades of the seventeenth century provides an insightful foil to English activity in the region as a whole, exposing patterns of European rivalry, national collaboration, and resource extraction. This article uses Newfoundland’s relationship with piracy as a focus to explore those issues, weaving together the histories of pirates, fishermen, and cod in an environmental approach that appreciates their interacting roles in the political ecology of Jacobean England, as well as the wider environment of the North Atlantic world
Do AI models produce better weather forecasts than physics-based models? A quantitative evaluation case study of Storm Ciarán
Get PDFThere has been huge recent interest in the potential of making operational weather forecasts using machine learning techniques. As they become a part of the weather forecasting toolbox, there is a pressing need to understand how well current machine learning models can simulate high-impact weather events. We compare forecasts of Storm Ciarán, a European windstorm that caused sixteen deaths and extensive damage in Northern Europe, made by machine learning and numerical weather prediction models. The four machine learning models considered (FourCastNet, Pangu-Weather, GraphCast and FourCastNet-v2) produce forecasts that accurately capture the synoptic-scale structure of the cyclone including the position of the cloud head, shape of the warm sector and location of warm conveyor belt jet, and the large-scale dynamical drivers important for the rapid storm development such as the position of the storm relative to the upper-level jet exit. However, their ability to resolve the more detailed structures important for issuing weather warnings is more mixed. All of the machine learning models underestimate the peak amplitude of winds associated with the storm, only some machine learning models resolve the warm core seclusion and none of the machine learning models capture the sharp bent-back warm frontal gradient. Our study shows there is a great deal about the performance and properties of machine learning weather forecasts that can be derived from case studies of high-impact weather events such as Storm Ciarán
Learning a strategy for preference elicitation in conversational recommender systems
Get PDFThis paper delves into the information elicitation aspect of Conversational Recommender Systems (CRS), presenting
an innovative method of selecting chatbot questions that result in the highest information gain when reconstructing the preference profile of a user, which allows one to achieve high-quality recommendations after a small number of conversational interactions. The proposed system comprises a Recommendation Module and a Preference Elicitation Module. The Recommendation Module leverages a Long Short-Term Memory (LSTM) network with an Attention mechanism and is optimised to reconstruct the preference profiles of new users based on limited information gathered through dialogue. The Preference Elicitation Module is trained using a reinforcement learning technique known as bot-play, where the Questioner Bot proactively prompts the Answerer Bot to provide item and attribute ratings, leveraging the reduction in the Recommendation model’s loss as a reward signal. This enables the model to learn an optimal questioning strategy, thereby maximising the accuracy of the representation of the user profile and the relevance of recommendations. The experimental results demonstrate the ability of the Recommendation component to learn item-attribute mappings, enabling the Questioner Bot to make accurate rating predictions with only a limited number of answered questions. Moreover, the trained Preference Elicitation policy model consistently outperforms the baseline model across both synthetic and real-world datasets, showcasing its ability to minimise the number of conversational turns required to achieve accurate recommendations
The UN committee on the rights of the child and Russia's deportation of children from Ukraine
No full textSince the International Criminal Court’s arrest warrants for Vladimir Putin and Maria Lvova-Belova for war crimes in March 2023, the deportation and unlawful transfer of children from occupied areas of Ukraine to the Russian Federation has been the subject of international legal, media and institutional attention. Exact numbers are difficult to come by. At the time of writing Children of War reports that 19,546 children have been deported. Reports suggest that many deported children may have been given Russian citizenship and illegally adopted. Others have been placed in re-education camps. In January 2024, concerns were again raised about the fate of deported children when President Putin signed a decree which further expedites the process for the granting of Russian citizenship. Under the decree orphans and children without parental care who are citizens of Ukraine can acquire Russian citizenship by personal decision of the President of the Russian Federation.
Russia has consistently denied deportation of Ukrainian children and has dismissed ICC arrest warrants on the grounds that, as a non-States Party, it does not recognise the Court. To date, there have been few opportunities to hold Russia to account. However, on 22 and 23 January, a delegation from the Russian Federation appeared before the UN Committee on the Rights of the Child as part of the periodic reporting process required under the Convention on the Rights of the Child (CRC). Ahead of the sessions, there was considerable interest in how Russia might respond to questions from the Committee on the deportation of children from Ukraine.
This post considers the proceedings before the UN Committee on the Rights of the Child and Russia’s justifications for the transfer of children from Ukraine. It will show that Russia’s explanations do little to assuage concerns about the transfer and treatment of children from Ukraine. Indeed, there should be grave concern that Russia continues to fall foul of international humanitarian law (IHL) and CRC standards
“Abiding there unliving” death and bare life in the unnamable
Get PDFGiorgio Agamben’s Homo Sacer proposes that the public display of power over life and death that Foucault restricts to the 18th century were not displaced by the new disciplinary structures associated with the hospital and the asylum, but remained contemporary with them. This notion of the simultaneity of surveillance and spectacle can be helpful in thinking about Beckett’s novel The Unnamable. Agamben’s work can also demonstrate the centrality of the character of Worm. In this way the broader notion of biopolitics can usefully illuminate the historical and political contexts of the book
Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
Get PDFBACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation