The formulation and simulation characteristics of two new global coupled climate models developed at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) are described. The models were designed to ...simulate atmospheric and oceanic climate and variability from the diurnal time scale through multicentury climate change, given our computational constraints. In particular, an important goal was to use the same model for both experimental seasonal to interannual forecasting and the study of multicentury global climate change, and this goal has been achieved.
Two versions of the coupled model are described, called CM2.0 and CM2.1. The versions differ primarily in the dynamical core used in the atmospheric component, along with the cloud tuning and some details of the land and ocean components. For both coupled models, the resolution of the land and atmospheric components is 2° latitude × 2.5° longitude; the atmospheric model has 24 vertical levels. The ocean resolution is 1° in latitude and longitude, with meridional resolution equatorward of 30° becoming progressively finer, such that the meridional resolution is 1/3° at the equator. There are 50 vertical levels in the ocean, with 22 evenly spaced levels within the top 220 m. The ocean component has poles over North America and Eurasia to avoid polar filtering. Neither coupled model employs flux adjustments.
The control simulations have stable, realistic climates when integrated over multiple centuries. Both models have simulations of ENSO that are substantially improved relative to previous GFDL coupled models. The CM2.0 model has been further evaluated as an ENSO forecast model and has good skill (CM2.1 has not been evaluated as an ENSO forecast model). Generally reduced temperature and salinity biases exist in CM2.1 relative to CM2.0. These reductions are associated with 1) improved simulations of surface wind stress in CM2.1 and associated changes in oceanic gyre circulations; 2) changes in cloud tuning and the land model, both of which act to increase the net surface shortwave radiation in CM2.1, thereby reducing an overall cold bias present in CM2.0; and 3) a reduction of ocean lateral viscosity in the extratropics in CM2.1, which reduces sea ice biases in the North Atlantic.
Both models have been used to conduct a suite of climate change simulations for the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment report and are able to simulate the main features of the observed warming of the twentieth century. The climate sensitivities of the CM2.0 and CM2.1 models are 2.9 and 3.4 K, respectively. These sensitivities are defined by coupling the atmospheric components of CM2.0 and CM2.1 to a slab ocean model and allowing the model to come into equilibrium with a doubling of atmospheric CO₂. The output from a suite of integrations conducted with these models is freely available online (seehttp://nomads.gfdl.noaa.gov/).
The coordinate accuracy of mini-drift tubes was measured by detecting the signal induced on their external electrodes. The electrodes (1-cm-wide strips) located perpendicularly to the anode wires ...were used to determine the particle coordinate. The rms coordinate accuracy of ∼0.4 mm was attained for four tube layers.
Neoproterozoic and Devonian mafic flows, sills and dykes associated with synchronous rifting events are widely distributed along the long-lived Mesoproterozoic to Mesozoic passive eastern margin of ...the Siberian Craton. Early Paleozoic magmatic events are also present, but are poorly studied, including Early Cambrian volcanic rocks in the Kharaulakh Range and ca. 450Ma age mafic intrusions of the Suordakh event in the Sette–Daban Range. Both suites of early Paleozoic magmatic rocks are characterized by high Ti concentrations (>3wt.% TiO2), ocean island basalt (OIB)-type trace element and rare earth element (REE) patterns, and high εNd(t) values that generally vary between 6 and 9. The Kharaulakh magmas were formed during low degree partial melting of an enriched region of mantle at depths >90km, generating a suite of alkaline basalts. In comparison, the Suordakh magmas were formed during higher degree partial melting of less enriched mantle at depths <90km, forming alkaline to subalkaline basalts. Both suites are characterized by εNd(t) values suggestive of interaction between enriched and depleted magmas and both were emplaced in within-plate tectonic settings. Although Kharaulakh and Suordakh magmatic rocks have relatively small areal extents, significant parts of them are likely hidden below clastic rocks of the Lower Carboniferous–Jurassic Verkhoyansk Complex. The Kharaulakh magmatic rocks may have counterparts in the Canadian Cordillera, that together could be of sufficient scale to define a Large Igneous Province (LIP). Early Cambrian mafic volcanic rocks in the study area are associated with locally distributed terrigenous units in both the Kharaulakh and Sette–Daban ranges, suggesting that this magmatism was related to a rifting event. Modeling of sedimentary basin subsidence in the Sette–Daban area is also supportive of an Early Cambrian rifting event. However, the intrusive rocks associated with the ca. 450Ma Suordakh mafic magmatic event are not related to any rift-related sediments or structures. Contemporaneous granites may be interpreted as silicic magmatism associated with a LIP event.
► Early Cambrian and Late Ordovician (ca. 450Ma) mafic magmatic events ► U–Pb baddeleyite dating, Sm–Nd and Rb–Sr isotopic study, geochemistry ► Early Cambrian rifting ► Late Ordovician (ca. 450Ma) rifting or LIP fragment
Phys. Rev. A 101, 012513 (2020) Fully relativistic approach is applied to evaluation of the nuclear recoil
effect on the bound-electron $g$ factor in hydrogenlike ions to first order in
the ...electron-to-nucleus mass ratio $m/M$ and to all orders in $\alpha Z$. The
calculations are performed in the range $1 \leqslant Z \leqslant 20$ for the
$g$ factors of $1s$, $2s$, $2p_{1/2}$, and $2p_{3/2}$ states. The $\alpha
Z$-dependence of the nontrivial QED recoil contribution as a function of $Z$ is
studied.
The local distribution of exciton levels in disordered cyanine-dye-based molecular nanoaggregates has been elucidated using fluorescence line narrowing spectroscopy. The observation of a ...Wigner−Dyson-type level spacing distribution provides direct evidence of the existence of level repulsion of strongly overlapping states in the molecular wires, which is important for the understanding of the level statistics, and therefore the functional properties, of a large variety of nanoconfined systems.
Climate change is a world‐wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for ...nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil–plant–atmosphere continuum. An increasing number of climate change studies are creating new opportunities for meaningful and high‐quality generalizations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis and upscaling. Many of these challenges relate to a lack of an established ‘best practice’ for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change.
To overcome these challenges, we collected best‐practice methods emerging from major ecological research networks and experiments, as synthesized by 115 experts from across a wide range of scientific disciplines. Our handbook contains guidance on the selection of response variables for different purposes, protocols for standardized measurements of 66 such response variables and advice on data management. Specifically, we recommend a minimum subset of variables that should be collected in all climate change studies to allow data re‐use and synthesis, and give guidance on additional variables critical for different types of synthesis and upscaling. The goal of this community effort is to facilitate awareness of the importance and broader application of standardized methods to promote data re‐use, availability, compatibility and transparency. We envision improved research practices that will increase returns on investments in individual research projects, facilitate second‐order research outputs and create opportunities for collaboration across scientific communities. Ultimately, this should significantly improve the quality and impact of the science, which is required to fulfil society's needs in a changing world.
RESUMEN
El cambio climático es una amenaza global para la biodiversidad, la estructura y funcionamiento de los ecosistemas y la habilidad de éstos para generar servicios ecosistémicos. Para poder comprender las causas y los mecanismos subyacentes, y poder predecir las consecuencias del cambio climático tanto para la naturaleza como para los seres humanos, debemos entender la magnitud y dirección de estos cambios a través del continuo suelo‐planta‐atmósfera. El creciente número de estudios sobre cambio climático brinda nuevas oportunidades para poder generalizar de forma más robusta y entender mejor los procesos implicados. Sin embargo, todavía hay grandes obstáculos en cuanto a la disponibilidad de datos y cómo de compatibles son los distintos estudios, que ponen en riesgo las oportunidades para reutilizar y sintetizar datos y comparar a distintas escalas. Estos obstáculos limitan nuesta habilidad para comprender los complejos procesos y mecanismos relacionados con el cambio climático en ecosistemas terrestres.
Para superar estos obstáculos, hemos recopilado recomendaciones metodológicas basadas en las mejores prácticas propuestas por las principales redes de investigación en ecología, avalados por 115 expertos de un amplio rango de disciplinas científicas. Nuestro manual contiene recomendaciones para la selección de variables respuesta para diferentes propósitos, y protocolos para realizar medidas estandarizadas de 66 posibles variables respuesta, así como sugerencias para la gestión de los datos obtenidos. Recomendamos específicamente un mínimo de variables que deben medirse en todos los estudios sobre cambio climático para permitir la reutilización y síntesis de datos. Además, sugerimos una serie de variables adicionales que pueden ser relevantes para distintos tipos de síntesis y para la comparación a distintas escalas. El objetivo de este esfuerzo comunitario es concienciar sobre la importancia de la aplicación de métodos estandarizados para facilitar la reutilización, disponibilidad, compatibilidad y transparencia de los datos. Mejorar las prácticas de investigación aumentará la eficiencia de proyectos de investigación individuales, facilitará resultados de investigación de segundo orden y creará oportunidades para la colaboración entre comunidades científicas. Por último, estas prácticas mejorarán considerablemente la calidad y el impacto de la ciencia, que se requiere para satisfacer las necesidades de la sociedad en un mundo cambiante.
摘要
气候变化正在对全球生物多样性, 生态系统结构, 功能和服务造成严重的威胁。为了理解这一过程的潜在驱动和机制, 以及预测这一过程对自然和人类社会的影响, 我们迫切的需要更好的了解气候变化对土壤‐植物‐大气系统影响的方向和强度。不断增加的相关方向的研究正在使对该研究领域的数据进行广泛而有意义的概括和总结成为可能, 从而进一步提高我们对这一重要过程的理解。然而, 显著的挑战依然存在, 特别是不同的生态研究产生的数据的可获得性和兼容性有着巨大差异, 这在一定程度上限制了研究数据的再度利用, 概括总结以及进一步推广应用。这个挑战与我们在观测气候变化和生态系统的关键影响及响应时缺乏良好的“最佳实践”有关。这个问题在很大程度上限制了我们对气候变化背景下陆地生态系统的复杂过程和机制的理解。
为了克服这些挑战, 我们收集了基于115个不同陆地生态研究领域的专家总结的主要生态研究网络和试验中的“最佳实践”方法。我们建立的“最佳实践”手册包括了对不同研究目的下选择测量的生态响应变量的建议, 测量66个生态响应变量的标准化流程, 以及如何进行数据管理的建议。特别地, 为了达到研究数据的可再度利用和融合, 我们推荐了一个在所有相关陆地生态研究中必须收集的最小数据集。同时针对不同类型的数据融合和推广应用, 我们给出了额外的关键数据和变量的收集建议。我们的工作希望能够有助于提高该研究领域的研究者对数据标准化的重要性和广泛应用的认识, 从而促进数据的再度利用, 数据的可获得性, 兼容性和透明度。我们期望改进的研究实践将能够增加每一个研究项目的投资回报率, 促进科研数据的二度产出, 以及创造更多的跨研究领域, 跨学科的合作机会。并最终, 显著提高我们的科学研究的质量和影响力, 以满足全球变化下社会对相关科学成果的需求。
We report on a search for charge-1/3 third-generation leptoquarks (LQ) produced in pp collisions at {radical}(s)=1.96 TeV using the D0 detector at Fermilab. Third-generation leptoquarks are assumed ...to be produced in pairs and to decay to a tau neutrino and a b quark with branching fraction B. We place upper limits on {sigma}(pp{yields}LQLQ)B{sup 2} as a function of the leptoquark mass M{sub LQ}. Assuming B=1, we exclude at the 95% confidence level third-generation scalar leptoquarks with M{sub LQ}<229 GeV.
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