Improving model-satellite comparisons of sea ice melt onset with a satellite simulator

Seasonal transitions in Arctic sea ice, such as the melt onset, have been found to be useful metrics for evaluating sea ice in climate models against observations. However, comparisons of melt onset dates between climate models and satellite observations are indirect. Satellite data products of melt onset rely on observed brightness temperatures, while climate models do not currently simulate brightness temperatures, and must therefore define melt onset with other modeled variables. Here we adapt a passive microwave sea ice satellite simulator, the Arctic Ocean Observation Operator (ARC3O), to produce simulated brightness temperatures that can be used to diagnose the timing of the earliest snowmelt in climate models, as we show here using Community Earth System Model version 2 (CESM2) ocean-ice hindcasts. By producing simulated brightness temperatures and earliest snowmelt estimation dates using CESM2 and ARC3O, we facilitate new and previously impossible comparisons between the model and satellite observations by removing the uncertainty that arises due to definition differences. Direct comparisons between the model and satellite data allow us to identify an early bias across large areas of the Arctic at the beginning of the CESM2 ocean-ice hindcast melt season, as well as improve our understanding of the physical processes underlying seasonal changes in brightness temperatures. In particular, the ARC3O allows us to show that satellite algorithm-based melt onset dates likely occur after significant snowmelt has already taken place. © 2022 Author

Arctic sea-ice evolution as modeled by Max Planck Institute for Meteorology's Earth system model

We describe the evolution of Arctic sea ice as modeled by the Max Planck Institute for Meteorology's Earth System Model (MPI-ESM). The modeled spatial distribution and interannual variability of the sea-ice cover agree well with satellite observations and are improved relative to the model's predecessor ECHAM5/MPIOM. An evaluation of modeled sea-ice coverage based on sea-ice area gives, however, conflicting results compared to an evaluation based on sea-ice extent and is additionally hindered by uncertainties in the observational record. Simulated trends in sea-ice coverage for the satellite period range from more strongly negative than observed to positive. The observed evolution of Arctic sea ice is incompatible with modeled internal variability and probably caused by external forcing. Simulated drift patterns agree well with observations, but simulated drift speed is generally too high. Simulated sea-ice volume agrees well with volume estimates of the PIOMAS reanalysis for the past few years. However, a preceding Arctic wide decrease in sea-ice volume starts much earlier in MPI-ESM than in PIOMAS. Analyzing this behavior in MPI-ESM's ocean model MPIOM, we find that the modeled volume trend depends crucially on the specific choice of atmospheric reanalysis forcing, which casts some doubt on the reliability of estimates of volume trends. In our CMIP5 scenario simulations, we find a substantial delay in sea-ice response to increasing CO2 concentration; a seasonally ice-free Arctic can result for a CO2 concentration of around 500 ppm. Simulated winter sea-ice coverage drops rapidly to near ice-free conditions once the mean Arctic winter temperature exceeds −5°C

Zwei Jahre pro-Q – Bilanz eines biokonformen Eutergesundheitsprogrammes

The pro-q-project is an udder health programme especially for organic farmers under Swiss conditions. The aim is to minimize the use of s antibiotics and to assure a good udder health state on the farms. At the end of the third project year of 100 project farms 16 participate for more than two years. The udder health situation of these 16 farms improved moderately in the second project year (37% of the cows with a so-matic cell count > 100’000/ml) compared to the year before project start (40% of the cows with a somatic cell count > 100’000/ml). Furthermore, a nearly linear increase of the arithmetic mean of herd lactation number (3.27 year before project start, 3.33 first project year, 3.44 second project year, resp.) could be found. The number of antibiotic treatments per cow and year decreased from 0.37 in the year before project start to 0.24 in the second project year

Management factors affecting udder health and effects of a one year extension program in organic dairy herds

The first part of this study was a cross-sectional analysis of the impact of 29 management factors on udder health in organic dairy farms in Switzerland. All 77 farms joined the extension program ‘pro-Q'. As a measure of udder health the theoretical bulk milk somatic cell count (TBMSCC) calculated by the monthly cow composite somatic cell count over a time period of 1 year was chosen. The basic udder health of the farms was determined by TBMSCC during the year prior to the start of the project (mean for all farms = 176 460 cells/ml). In the multivariable analysis, the five factors ‘swiss brown breed', ‘alpine summer pasturing', ‘calf feeding with milk from mastitis diseased cows', ‘hard bedding' and ‘no post-milking' remained as significant risk factors on udder health. In the second part of the study, the development of management factors and the udder health situation affected by an extension program after 1 year was investigated. A partial improvement of the management factors on the farms but no overall improvement on udder health and no association between management changes and udder health changes were found. Improvement of udder health was more likely in farms with higher basic TBMSCC than in those farms with less udder health problems at the beginning of the projec

EHEC – kein spezifisches Problem nachhaltiger Landwirtschaft - [EHEC – A problem not specific to sustainable agriculture] [La EHEC – no es un problema específico de la agricultura sostenible] - [EHEC – Non è un problema specifi-co dell’agricoltura biologica] - [ECEH n’est pas un problème dû à l’agriculture durable] - [EHEC – nem speciálisan a fenntartható mezőgazdaság gondja] - [ECEH n’est pas un problème dû à l’agriculture durable]

DEUTSCH Über den EHEC-Erreger, der in Deutschland zu über dreissig tragischen Todesfällen geführt hat, ist viel spekuliert worden. Unterdessen konnten die Verbreitungswege nahezu aufgeklärt werden, während die Entstehung des Krankheitserregers noch weitgehend unklar ist. Im Zusammenhang mit dem EHEC-Ausbruch wurde auch die Frage erörtert, ob bestimmte Landwirtschaftsmethoden (zum Beispiel gemischte Betriebe mit Tierhaltung und Pflanzenbau oder die organische Düngung von Gemüse) oder ob gewisse Hygienisierungsmethoden für frische, konsumfähige Produkte(wie zum Beispiel die Verwendung von schonenden, weniger Rückstände verursachenden organischen Säuren) das Risiko erhöhen könnten. Diese Dokumentation geht nicht auf die aktuellen Fälle von EHEC in Norddeutschland ein, sondern liefert an diesem Beispiel Hintergrundinformationen zur Frage, wie nachhaltige, in Kreisläufen arbeitende Landwirtschaftsmethoden mit vom Tier auf den Menschen übertragbare Krankheitserreger (Zoonosen) umgehen. ENGLISH There has been much speculation about the pathogenic EHEC bacterial strain that has tragically claimed the lives of more than 30 people so far in Germany. Meanwhile, the transmission pathways have for the most part been identified. The origin of the pathogen, however, is largely unclear. In the context of the EHEC outbreak there have been debates as to whether certain agriculturalmethods (e.g. mixed holdings including both livestock and crop production, or the use of organic fertilizers for vegetable production) or certain sanitization methods for fresh consumable products (such as the use of organic acids, a mild treatment that leaves fewer residues) may increase the risk of infection. This document does not address the current epidemiological situation of the outbreak in northern Germany. Its purpose is rather to provide background information on the question of how sustainable agricultural methods based on nutrient cycling deal with pathogens that can be transmitted from animals to humans (zoonoses). CASTELLANO Mucho se ha especulado sobre la bacteria patógena Escherichia coli enterohemorrágica (ECEH), que ha ocasionado más de treinta muertes trágicas en Alemania. Hasta ahora casi se ha podido esclarecer la via de su propagación, mientras que sigue estando poco claro como ha aparecido el agente patógeno. Con el brote de la ECEH se ha cuestionado si determinadas prácticas agrícolas (por ejemplo, mantener explotaciones mixtas con ganado y cultivos, o la fertilización orgánica de los vegetales) o si los métodos de higiene para productos frescos, listos para el consumo (como por ejemplo, el uso de ácidos orgánicos menos agresivos y con menor riesgo de dejar residudos), pudieran incrementar los riesgos. Esta documento no se refiere sólo a los casos actuales de ECEH en el norte de Alemania, sino que proporciona, información básica de fondo, aprovechando este ejemplo, sobre como los métodos de producción agraria de ciclos cerrados con animales evitan forma sostenible que los patógenos generadores de enfermedades contagiosas (zoonosis) trasmisibles al ser humano. ITALIANO A proposito dell’insorgenza di EHEC è stata sollevata la questione se determinati metodi agricoli (per esempio aziende miste con allevamento di animali e produzione vegetale o la concimazione organica di ortaggi) oppure se determinati metodi di igienizzazione per pro-dotti freschi adatti al consumo (come per esempio l’impiego di acidi organici che provocano meno residui) possano aumentare i rischi. La presente documentazione non entra nei particolari degli attuali casi di EHEC nella Ger-mania settentrionale bensì fornisce informazioni d’approfondimento su come i me-todi agri-coli sostenibili basati sui cicli degli elementi nutritivi trattano la questione degli agenti pato-geni trasmissibili dagli animali all’uomo (zoonosi). HUNGARIAN Sok a spekuláció az EHEC kórokozót illetően, amely Németországban harmincnál is több tragikus halálesethez vezetett. Időközben a terjedés útját már csaknem teljesen felderítették, míg a kórokozó létrejöttéről még szinte semmit sem tudunk. Az EHEC fertőzés kitörése kapcsán az a kérdés is felmerült, hogy bizonyos mezőgazdasági módszerek (pl. a vegyes üzemek, melyek egyaránt foglalkoznak növénytermesztéssel és állattenyésztéssel, vagy a zöldségek szerves trágyázása), ill. a friss, fogyasztásra kész termékek egyes fertőtlenítési módszerei (így pl. a kímélőbb, kevesebb hulladékot eredményező szerves savak alkalmazása) nem növelhetik-e a kockázatot. A jelen tanulmány nem a Németország északi részén kialakult aktuális EHEC esetekkel foglalkozik, hanem háttér-információval szolgál arról, hogy a körforgásos működésű, fenntartható mezőgazdasági módszerek milyen kapcsolatban lehetnek az állatról emberre terjedő betegségekkel, az ún. zoonózisokkal. FRANCAIS ECEH n’est pas un problème dû à l’agriculture durabl

Application of gel microsphere processes to preparation of Sphere-Pac nuclear fuel

Sphere-Pac fabrication of nuclear fuels using two or more sizes of oxide or carbide spheres is ideally suited to nonproliferation-fuel cycles and remote refabrication. The sizes and compositions of spheres necessary for such fuel cycles have not been commonly prepared; therefore, modifications of sol-gel processes to meet these requirements are being developed and demonstrated

Antarctic Sea Ice Area in CMIP6

Fully coupled climate models have long shown a wide range of Antarctic sea ice states and evolution over the satellite era. Here, we present a high‐level evaluation of Antarctic sea ice in 40 models from the most recent phase of the Coupled Model Intercomparison Project (CMIP6). Many models capture key characteristics of the mean seasonal cycle of sea ice area (SIA), but some simulate implausible historical mean states compared to satellite observations, leading to large intermodel spread. Summer SIA is consistently biased low across the ensemble. Compared to the previous model generation (CMIP5), the intermodel spread in winter and summer SIA has reduced, and the regional distribution of sea ice concentration has improved. Over 1979–2018, many models simulate strong negative trends in SIA concurrently with stronger‐than‐observed trends in global mean surface temperature (GMST). By the end of the 21st century, models project clear differences in sea ice between forcing scenarios

Temporal dynamics of ikaite in experimental sea ice

Ikaite (CaCO3 · 6H2O) is a metastable phase of calcium carbonate that normally forms in a cold environment and/or under high pressure. Recently, ikaite crystals have been found in sea ice, and it has been suggested that their precipitation may play an important role in air-sea CO 2 exchange in ice-covered seas. Little is known, however, of the spatial and temporal dynamics of ikaite in sea ice. Here we present evidence for highly dynamic ikaite precipitation and dissolution in sea ice grown at an outdoor pool of the Sea-ice Environmental Research Facility (SERF) in Manitoba, Canada. During the experiment, ikaite precipitated in sea ice when temperatures were below -4 °C, creating three distinct zones of ikaite concentrations: (1) a millimeter-to-centimeter-thin surface layer containing frost flowers and brine skim with bulk ikaite concentrations of >2000 μmol kg-1, (2) an internal layer with ikaite concentrations of 200-400 μmol kg -1, and (3) a bottom layer with ikaite concentrations of <100 μmol kg-1. Snowfall events caused the sea ice to warm and ikaite crystals to dissolve. Manual removal of the snow cover allowed the sea ice to cool and brine salinities to increase, resulting in rapid ikaite precipitation. The observed ikaite concentrations were on the same order of magnitude as modeled by FREZCHEM, which further supports the notion that ikaite concentration in sea ice increases with decreasing temperature. Thus, varying snow conditions may play a key role in ikaite precipitation and dissolution in sea ice. This could have a major implication for CO2 exchange with the atmosphere and ocean that has not been accounted for previously