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| Registros recuperados: 16 | |
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| Plaisant, M. |
| Empirical models already exist for ambient noise spectral density function of frequency, sea state or wind speed but they give no information on the spatial structure or coherence of the noise field which is essential as soon as array beamforming is involved. We have developed a model which computes the spatial coherence matrix of the noise field due to a continuous distribution of sources located at the sea surface, and also the noise power spectral density after classical beamforming on an equidistant hydrophones linear array. In this model, propagation effects like rays bending due to variations of index of refraction and multiple bottom and surface reflections are taken into account. Principles of the modeling are presented and results demonstrate that... |
| Tipo: Text |
Palavras-chave: Spectral analysis; Models; Wind speed; Sea surface; Surface water waves; Acoustic equipment; Sound waves; Underwater noise; Ambient noise. |
| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/1990/acte-1143.pdf |
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| Martin, Adrien; Boutin, Jacqueline; Hauser, Daniele; Reverdin, Gilles; Parde, Mickael; Zribi, Mehrez; Fanise, Pascal; Chanut, Jerome; Lazure, Pascal; Tenerelli, Joseph; Reul, Nicolas. |
| A renewal of interest for the radiometric L-band Sea Surface Salinity (SSS) remote sensing appeared in the 1990s and led to the Soil Moisture and Ocean Salinity (SMOS) satellite launched in November 2009 and to the Aquarius mission (launched in June 2011). However, due to low signal to noise ratio, retrieving SSS from L-band radiometry is very challenging. In order to validate and improve L-band radiative transfer model and salinity retrieval method used in SMOS data processing, the Cooperative Airborne Radiometer for Ocean and Land Studies (CAROLS) was developed. We analyze here a coastal flight (20 May 2009), in the Gulf of Biscay, characterized by strong SSS gradients (28 to 35 pss-78). Extensive in-situ measurements were gathered along the plane track.... |
| Tipo: Text |
Palavras-chave: L-band; Microwave radiometry; Remote sensing; Retrieval method; Sea surface salinity (SSS); Soil Moisture and Ocean Salinity (SMOS); Wind speed. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00079/18997/16600.pdf |
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| Wanninkhof, R.; Trinanes, J.. |
| An increase in global wind speeds over time is affecting the global uptake of CO2 by the ocean. We determine the impact of changing winds on gas transfer and CO2 uptake by using the recently updated, global high-resolution, cross-calibrated multiplatform wind product (CCMP-V2) and a fixed monthly pCO(2) climatology. In particular, we assess global changes in the context of regional wind speed changes that are attributed to large-scale climate reorganizations. The impact of wind on global CO2 gas fluxes as determined by the bulk formula is dependent on several factors, including the functionality of the gas exchange-wind speed relationship and the regional and seasonal differences in the air-water partial pressure of CO2 gradient (pCO(2)). The latter also... |
| Tipo: Text |
Palavras-chave: Ocean carbon cycle; Air-sea CO2 fluxes; Wind speed. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00661/77324/78784.pdf |
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| Golubkin, Pavel A.; Chapron, Bertrand; Kudryavtsev, Vladimir N.. |
| Wind-generated waves in the Kara, Laptev, and East-Siberian Seas are investigated using altimeter data from Envisat RA-2 and SARAL-AltiKa. Only isolated ice-free zones had been selected for analysis. Wind seas can be treated as pure wind-generated waves without any contamination by ambient swell. Such zones were identified using ice concentration data from microwave radiometers. Altimeter data, both significant wave height (SWH) and wind speed, for these areas were further obtained for the period 2002-2012 using Envisat RA-2 measurements, and for 2013 using SARAL-AltiKa. Dependencies of dimensionless SWH and wavelength on dimensionless wave generation spatial scale are compared to known empirical dependencies for fetch-limited wind wave development. We... |
| Tipo: Text |
Palavras-chave: Altimetry; Remote sensing; Satellite altimeter; Significant wave height; Wind speed. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00302/41330/40642.pdf |
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| Yin, Xiaobin; Boutin, Jacqueline; Martin, Nicolas; Spurgeon, Paul; Vergely, Jean-luc; Gaillard, Fabienne. |
| The wind speed (WS) provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) is used to initialize the retrieval process of WS and Sea Surface Salinity (SSS) obtained by the Soil Moisture and Ocean Salinity (SMOS) mission. This process compensates for the lack of onboard instrument providing a measure of ocean surface WS independent of the L-band radiometer measurements. The SMOS-retrieved WS in the center of the swath (± 300 km) is adjusted regarding to its a priori estimate. The quality of the SMOS-retrieved SSS (SSSSMOS) is better at the center of the swath than at the edge of the swatch because the larger number of brightness temperature measurements available at the center of the swath reduces the effects of noise and because the... |
| Tipo: Text |
Palavras-chave: SMOS; SSMIS; ECMWF; Wind speed; Salinity. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00158/26970/25261.pdf |
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| Jang, Jae-cheol; Park, Kyung-ae; Mouche, Alexis; Chapron, Bertrand; Lee, Ji-hyun. |
| In this study, using in situ measurements at 17 buoy stations off the Korean Peninsula, C-band model (CMOD) functions for Sentinel-1A/B IW mode synthetic aperture radar (SAR) data were validated. In total, 395 Sentinel-1A/B IW mode dual-vertical polarized images were used for collocation with in situ measurements from May 1, 2015, to September 30, 2017, and 807 matchup points were obtained. Prior to the validation, preprocessing such as speckle noise reduction and ship and land masking was completed. The in situ wind speeds were converted to a 10-m neutral wind considering atmospheric stability. High-resolution wind speeds were estimated by using the CMOD functions such as CMOD4, CMOD_IFR2, CMOD5, CMOD5.N, and CMOD5.Na. The root-mean-square errors of... |
| Tipo: Text |
Palavras-chave: C-band model (CMOD) functions; Synthetic aperture radar (SAR); Sentinel-1A/B; Wind speed; Wind speed error. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62395/66792.pdf |
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| Hartman, S.e.; Hartman, M. C.; Hydes, D.j.; Smythe-wright, D.; Gohin, Francis; Lazure, Pascal. |
| Unusually high chlorophyll values (~ 14 mg chl m− 3 at 5 m depth), recorded on a ship of opportunity (SOO) in July 2010, indicated the occurrence of a potential Harmful Algal Bloom (HAB) in the Western approaches of the English Channel. This bloom, located at 49.7°N, 3.2°W was observed via complementary datasets. These included data from samples collected for microscopic phytoplankton identification, information from satellite maps to follow geographical bloom development and in situ data to identify hydrographic factors related to bloom initiation. The relationships between chlorophyll-fluorescence, temperature, salinity and wind speed were examined. The intense summer bloom predominantly consisted of the dinoflagellate Karenia mikimotoi and followed an... |
| Tipo: Text |
Palavras-chave: Karenia mikimotoi; Harmful algae; Wind speed; Temperature; Low salinity water; French Atlantic rivers; English Channel; Ferry-box. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00199/31033/29437.pdf |
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| Fan, Shengren; Zhang, Biao; Mouche, Alexis; Perrie, William; Zhang, Jun A.; Zhang, Guosheng. |
| Under extreme weather conditions, the imprints of kilometer-scale marine atmospheric boundary layer roll vortices on the ocean surface are clearly visible in synthetic aperture radar (SAR) images of storms. Therefore, information about wind direction in storms can be obtained by analyzing SAR image features caused by boundary layer rolls. VH-polarized SAR imagery captures the structural features of storms well and shows prominent image gradients along the radial directions of the storm. The signal-to-noise ratios of VH-polarized images are small in low wind speed areas, but they are large in the same regions of VV-polarized images. Also, the capability of retrieving the atmospheric rolls orientation in VV-polarization is found to be sensitive to incidence... |
| Tipo: Text |
Palavras-chave: Synthetic aperture radar; Radar polarimetry; Wind speed; Atmospheric modeling; Spaceborne radar; Radar measurements; Synthetic aperture radar (SAR); Tropical cyclone (TC); Wind direction. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72143/70953.pdf |
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| Sapp, Joseph W.; Mouche, Alexis; Jelenak, Zorana; Chang, Paul S.; Frasier, Stephen J.. |
| In Winter 2017, the University of Massachusetts Amherst's Imaging Wind and Rain Airborne Profiler (IWRAP) was flown on a National Oceanic and Atmospheric Administration (NOAA) WP-3D Hurricane Hunter aircraft under the direction of scientists from Center for Satellite Applications and Research (STAR) at NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) over the North Atlantic ocean out of Shannon, Ireland. IWRAP is a dual-frequency, conically scanning, profiling Doppler radar initially developed by Microwave Remote Sensing Laboratory (MIRSL) at the University of Massachusetts Amherst that is routinely installed on the NOAA WP-3D research aircraft. The flight on February 6, 2017, targeted a region of high winds (greater than 30... |
| Tipo: Text |
Palavras-chave: Satellites; Aircraft; Spaceborne radar; Synthetic aperture radar; Sea measurements; Wind speed; C-band; Cross polarization; Normalized radar cross section (NRCS); Ocean winds; Scatterometry. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00640/75251/75648.pdf |
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| Cardin, V.; Cornejo Rodríguez, M.P.. |
| Series de tiempo de la velocidad del viento de Bahía de Caráquez y Manta, y altura de olas de Jaramijó durante 1979-1980 han sido analizados, observándose que las principales frecuencias, se encuentran comprendidas entre 2 días y 1 año, similares a aquellas de las ondas de largo período. Para esto se utilizaron técnicas estadísticas tales como la media corrida y el análisis espectral. Se estableció en forma clara, así mismo, la presencia de periocidades de 40-60 días para las series de viento similares a las referidas por Spíllane et al. (1987). Enfield (1987), y Luther (1980) entre otros. El régimen de vientos analizado coincide con el régimen de los vientos alisios del sur, los cuales decaen y se incrementan para las mismas épocas como producto del... |
| Tipo: Journal Contribution |
Palavras-chave: Wind speed; Wind speed; Http://aims.fao.org/aos/agrovoc/c_29582. |
| Ano: 1990 |
URL: http://hdl.handle.net/1834/2166 |
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| Mendes,AS; Moura,DJ; Morello,GM; Carvalho,TMR; Sikorski,RR. |
| ABSTRACT Rearing environmental conditions are important for turkey production, because this bird is particularly sensitive to heat stress. This study aimed at measuring the wattle temperature response of turkeys of three different ages (61, 96, and 131 days old) exposed to different combinations of dry bulb temperature, relative humidity, and wind speed ranges, as an indication of their physiological responses. The experiment was conducted with 42 male birds housed in a controlled environment chamber and exposed to different combinations of two air speed (WS) ranges (WS1 = 0.3-0.6 ms-1, considered low, and WS2 = 1.2-1.6 ms-1, considered high), dry bulb temperature (DBT) between 22 and 34 °C, and relative humidity (RH) between 40 to 90 %. The statistical... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Wind speed; Thermal comfort; Relative humidity; Environmental exposure. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2015000400439 |
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| Alheidary, Majid Hazim. |
| Spray drift is defined as the movement of small spray droplets as particles or vapour at the time of application or soon thereafter out of the target zone by the action of air or incorrect nozzle mounted on boom. Several factors are known to affect spray drift with significant differences such as physical parameters, technological parameters, and meteorological parameters. The mitigation of spray drift from agricultural application is an important issue that concerns many researchers and authors working with field tests. Wind tunnel technique is considered as an alternative method to assess spray drift that move away from the target site intended under different settings as boom heights and wind speeds. In 2015, IRSTEA Montpellier wind tunnel was fitted... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Drift ratio; Wind tunnel; Nozzle type; Wind speed. |
| Ano: 2020 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/5665 |
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| Registros recuperados: 16 | |
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