4 research outputs found
Multiâdiagnostic multiâmodel ensemble forecasts of aviation turbulence
Turbulence is one of the major weather hazards to aviation. Studies have shown that clearâair turbulence may well occur more frequently with future climate change. Currently the two World Area Forecast Centres use deterministic models to generate forecasts of turbulence. It has been shown that the use of multiâmodel ensembles can lead to more skilful turbulence forecasts. It has also been shown that the combination of turbulence diagnostics can also produce more skilful forecasts using deterministic models. This study puts the two approaches together to expand the range of diagnostics to include predictors of both convective and mountain wave turbulence, in addition to clearâair turbulence, using two ensemble model systems. Results from a 12 month global trial from September 2016 to August 2017 show the increased skill and economic value of including a wider range of diagnostics in a multiâdiagnostic multiâmodel ensemble
The Atacama Cosmology Telescope: A Catalog of >4000 SunyaevâZelâdovich Galaxy Clusters
We present a catalog of 4195 optically confirmed SunyaevâZel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg2 of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M500c > 3.8 Ă 1014 Mâ, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2farcm4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg2), the Hyper Suprime-Cam Subaru Strategic Program (469 deg2), and the Kilo Degree Survey (825 deg2). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr
Sinopse das espécies de Menticirrhus Gill, 1861 (Osteichthyes, Sciaenidae) do Atlùntico Ocidental
Discute-se a nomenclatura e a taxonomia das espĂ©cies de Menticirrhus Gill, 1861 (Sciaenidae) do AtlĂąntico Ocidental. As formas mencionadas na literatura foram reexaminadas para serem atribuĂdas Ă s duas espĂ©cies achadas nas costas do Brasil, M. americanus (L.) e M. littoralis (Holbrook). ReferĂȘncias a M. littoralis sĂŁo frequentemente feitas, na literatura de autores sul-americanos, sob o nome de M. martinicensis Cuvier.<br>The taxonomy and nomenclature of the Western Atlantic species of Menticirrhus Gill, 1861 (Sciaenidae) are discussed. Forms mentioned in the past literature have been reexamined to be atributed to one of the two species that occur along the Brazilian coast: M. americanus (L.) and M. littoralis (Holbrook). References to M. littoralis, frequently mentioned in the literature by South American authors, actually refer to M. littoralis