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| Registros recuperados: 25 | |
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| Mcphaden, Mj; Foltz, Jr; Lee, T.; Murty, V. S. N.; Ravichandran, Muthalagu; Vecchi, Ga; Vialard, Jerome; Wiggert, J.d.; Yu, L.. |
| Cyclone Nargis (Figure 1a) made landfall in Myanmar (formerly Burma) on 2 May 2008 with sustained winds of approximately 210 kilometers per hour, equivalent to a category 3–4 hurricane. In addition, Nargis brought approximately 600 millimeters of rain and a storm surge of 3–4 meters to the low-lying and densely populated Irrawaddy River delta. In its wake, the storm left an estimated 130,000 dead or missing and more than $10 billion in economic losses. It was the worst natural disaster to strike the Indian Ocean region since the 26 December 2004 tsunami and the worst recorded natural disaster ever to affect Myanmar. |
| Tipo: Text |
Palavras-chave: IndOOS; Bay of Bengal; Cyclone Nargis. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00185/29643/28009.pdf |
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| De Boyer Montegut, Clement; Vialard, Jerome; Shenoi, S. S. C.; Shankar, D.; Durand, Fabien; Ethe, Christian; Madec, Gurvan. |
| A global ocean general circulation model (OGCM) is used to investigate the mixed layer heat budget of the northern Indian Ocean (NIO). The model is validated against observations and shows fairly good agreement with mixed layer depth data in the NIO. The NIO has been separated into three subbasins: the western Arabian Sea (AS), the eastern AS, and the Bay of Bengal (BoB). This study reveals strong differences between the western and eastern AS heat budget, while the latter basin has similarities with the BoB. Interesting new results on seasonal time scales are shown. The penetration of solar heat flux needs to be taken into account for two reasons. First, an average of 28 W m(-2) is lost beneath the mixed layer over the year. Second, the penetration of... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; General circulation model; Southeastern arabian sea; Thermal structure; Summer monsoon; Solar radiation; Pacific ocean; Barrier layer; Bengal; Bay. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00185/29639/27985.pdf |
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| Mcphaden, M. J.; Meyers, G.; Ando, K.; Masumoto, Y.; Murty, V. S. N.; Ravichandran, M.; Syamsudin, F.; Vialard, Jerome; Yu, L.; Yu, W.. |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00185/29633/27991.pdf |
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| Troccoli, Alberto; Balmaseda, Magdalena A.; Segschneider, Joachim; Vialard, Jerome; Anderson, David L. T.; Haines, Keith; Stockdale, Tim; Vitart, Frédéric; Fox, Alan D.. |
| This paper is an evaluation of the role of salinity in the framework of temperature data assimilation in a global ocean model that is used to initialize seasonal climate forecasts. It is shown that the univariate assimilation of temperature profiles, without attempting to correct salinity, can induce first-order errors in the subsurface temperature and salinity fields. A recently developed scheme by A. Troccoli and K. Haines is used to improve the salinity field. In this scheme, salinity increments are derived from the observed temperature, by using the model temperature and salinity profiles, assuming that the temperature-salinity relationship in the model profiles is preserved. In addition, the temperature and salinity fields are matched below the... |
| Tipo: Text |
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| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00251/36272/34839.pdf |
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| Vialard, Jerome; Duvel, J. P.; Mcphaden, M. J.; Bouruet-aubertot, P.; Ward, Ben; Key, E.; Bourras, D.; Weller, Robert; Minnett, P.; Weill, A.; Cassou, C.; Eymard, L.; Fristedt, T.; Basdevant, C.; Dandonneau, Y.; Duteil, O.; Izumo, T.; De Boyer Montegut, Clement; Masson, S.; Marsac, F.; Menkes, C.; Kennan, S.. |
| A field experiment in the southwestern Indian Ocean provides new insights into ocean-atmosphere interactions in a key climatic region. |
| Tipo: Text |
Palavras-chave: Madden julian oscillation; Southwest indian ocean; Surface temperature; Mixed layer; Intraseasonal variability; Rainfall variability; Tropical cyclones; Western pacific; Dipole mode; El nino. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00185/29634/27990.pdf |
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| Currie, J. C.; Lengaigne, M.; Vialard, Jerome; Kaplan, David; Aumont, Olivier; Naqvi, S. W. A.; Maury, Olivier. |
| The Indian Ocean Dipole (IOD) and the El Nino/Southern Oscillation (ENSO) are independent climate modes, which frequently co-occur, driving significant interannual changes within the Indian Ocean. We use a four-decade hindcast from a coupled biophysical ocean general circulation model, to disentangle patterns of chlorophyll anomalies driven by these two climate modes. Comparisons with remotely sensed records show that the simulation competently reproduces the chlorophyll seasonal cycle, as well as open-ocean anomalies during the 1997/1998 ENSO and IOD event. Results suggest that anomalous surface and euphotic-layer chlorophyll blooms in the eastern equatorial Indian Ocean in fall, and southern Bay of Bengal in winter, are primarily related to IOD forcing.... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00166/27749/25945.pdf |
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| Vialard, Jerome; Shenoi, S. S. C.; Mccreary, J. P.; Shankar, D.; Durand, F.; Fernando, V.; Shetye, S. R.. |
| A new observational record of upper-ocean currents at 15 degrees N on the western coast of India is dominated by intraseasonal (55 - 110 day) variations of alongshore currents, whereas sea level at the same location has a clear seasonal signal. These observations can be interpreted within the framework of linear wave theory. At 15 degrees N, the minimum period for planetary waves is similar to 90 day, meaning that intraseasonal energy is largely trapped at the coast in the form of poleward-propagating Kelvin waves, while lower-frequency signals associated with the annual cycle can radiate offshore as planetary waves. This dynamical difference results in a steeper offshore slope of sea level at intraseasonal timescale, and thus stronger geostrophic... |
| Tipo: Text |
Palavras-chave: Variability; Dynamics; Circulation; Currents. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00185/29631/27993.pdf |
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| Vialard, Jerome; Foltz, G. R.; Mcphaden, M. J.; Duvel, J. P.; De Boyer Montegut, Clement. |
| A moored buoy was recently deployed at 8 degrees S, 67 degrees E in the shallow thermocline region of the Indian Ocean known as "Seychelles-Chagos Thermocline Ridge'' (SCTR), where the Madden Julian Oscillation (MJO) is associated with strong sea surface temperature (SST) variability. We use observations from this mooring to describe the oceanic signature of two MJOs between November 2007 and February 2008. The four-month average upper ocean heat balance was largely between heating by atmospheric forcing (2.0 +/- 0.3 degrees C/month) and a significant cooling by subsurface processes (-2.2 +/- 0.8 degrees C/month), consistent with climatological Ekman pumping in the region. The two MJO events resulted in strong intraseasonal SST variations (1.5 to 2 degrees... |
| Tipo: Text |
Palavras-chave: Layer heat balance; Paific; Perturbations; Prediction; Fluxes. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00185/29636/27988.pdf |
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| Masson, S; Luo, Jj; Madec, G; Vialard, Jerome; Durand, F; Gualdi, S; Guilyardi, E; Behera, S; Delecluse, P; Navarra, A; Yamagata, T. |
| In the present study, we use a coupled model to evaluate the effect of shallow salinity stratification on the sea surface temperature (SST) and on the monsoon onset in the southeastern Arabian Sea (SEAS). A 100-year control experiment shows that the coupled model reproduces the main climatic features in this region in terms of SST, precipitation and barrier layer (BL). A 100-year sensitivity experiment (where BL effects have been suppressed in the SEAS) shows that BL enhances the spring SST warming by 0.5 degrees C, and leads to a statistically significant increase of precipitation in May (3 mm/day) linked to an early (10 to 15 days) monsoon onset. This suggests that the BL extent may be a useful predictor of the summer monsoon onset in the area with a... |
| Tipo: Text |
Palavras-chave: Summer monsoon season; Surface temperature; Indian ocean; Mixed layer; Northeast monsoon; Southwest monsoon; Onset vortex; Coupled GCM; Mechanisms; Evolution. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00203/31422/29819.pdf |
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| Akhil, V. P.; Durand, Fabien; Lengaigne, Matthieu; Vialard, Jerome; Keerthi, M. G.; Gopalakrishna, V. V.; Deltel, Charles; Papa, Fabrice; De Boyer Montegut, Clement. |
| In response to the Indian Monsoon freshwater forcing, the Bay of Bengal exhibits a very strong seasonal cycle in sea surface salinity (SSS), especially near the mouths of the Ganges-Brahmaputra and along the east coast of India. In this paper, we use an eddy-permitting (∼25 km resolution) regional ocean general circulation model simulation to quantify the processes responsible for this SSS seasonal cycle. Despite the absence of relaxation toward observations, the model reproduces the main features of the observed SSS seasonal cycle, with freshest water in the northeastern Bay, particularly during and after the monsoon. The model also displays an intense and shallow freshening signal in a narrow (∼100 km wide) strip that hugs the east coast of India, from... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30819/29189.pdf |
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| Izumo, Takeshi; Masson, Sebastien; Vialard, Jerome; De Boyer Montegut, Clement; Behera, Swadhin K.; Madec, Gurvan; Takahashi, Keiko; Yamagata, Toshio. |
| The Madden-Julian oscillation (MJO) is the main component of intraseasonal variability of the tropical convection, with clear climatic impacts at an almost-global scale. Based on satellite observations, it is shown that there are two types of austral-summer MJO events (broadly defined as 30-120 days convective variability with eastward propagation of about 5 m/s). Equatorial MJO events have a period of 30-50 days and tend to be symmetric about the equator, whereas MJO events centered near 8A degrees S tend to have a longer period of 55-100 days. The lower-frequency variability is associated with a strong upper-ocean response, having a clear signature in both sea surface temperature and its diurnal cycle. These two MJO types have different interannual... |
| Tipo: Text |
Palavras-chave: Intraseasonal Madden-Julian oscillation (MJO); Seychelles-Chagos thermocline ridge/thermocline dome of the Indian Ocean; Indian Ocean dipole (IOD); El Nino southern oscillation (ENSO); Diurnal cycle; Oceanic diurnal warm layers; Air-sea interactions; Ocean-atmosphere coupling; Interannual variations; Mixed layer; Australian weather. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12416/9221.pdf |
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| Izumo, Takeshi; Vialard, Jerome; Lengaigne, Matthieu; De Boyer Montegut, Clement; Behera, Swadhin K.; Luo, Jing-jia; Cravatte, Sophie; Masson, Sebastien; Yamagata, Toshio. |
| El Nino-Southern Oscillation (ENSO) consists of irregular episodes of warm El Nino and cold La Nina conditions in the tropical Pacific Ocean(1), with significant global socio-economic and environmental impacts(1). Nevertheless, forecasting ENSO at lead times longer than a few months remains a challenge(2,3). Like the Pacific Ocean, the Indian Ocean also shows interannual climate fluctuations, which are known as the Indian Ocean Dipole(4,5). Positive phases of the Indian Ocean Dipole tend to co-occur with El Nino, and negative phases with La Nina(6-9). Here we show using a simple forecast model that in addition to this link, a negative phase of the Indian Ocean Dipole anomaly is an efficient predictor of El Nino 14 months before its peak, and similarly, a... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11304/7831.pdf |
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| Menkes, Christophe E.; Lengaigne, Matthieu; Levy, Marina; Ethe, Christian; Bopp, Laurent; Aumont, Olivier; Vincent, Emmanuel; Vialard, Jerome; Jullien, Swen. |
| In this paper, we explore the global responses of surface temperature, chlorophyll and primary production to tropical cyclones (TCs). Those ocean responses are first characterized from the statistical analysis of satellite data under ~1000 TCs over the 1998-2007 period. Besides the cold wake, the vast majority of TCs induce a weak chlorophyll response, with only ~10% of induced blooms exceeding 0.1 mg.m-3. The largest chlorophyll responses mostly occur within coastal regions, in contrast to the strongest cold wakes that generally occur farther offshore. To understand this decoupling, we analyze a coupled dynamical-biogeochemical oceanic simulation forced by realistic wind vortices applied along observed TC tracks. The simulation displays a realistic... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44449/44121.pdf |
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| Keerthi, Madhavan Girijakumari; Lengaigne, Matthieu; Levy, Marina; Vialard, Jerome; Parvathi, Vallivattathillam; De Boyer Montegut, Clement; Ethe, Christian; Aumont, Olivier; Suresh, Iyyappan; Akhil, Valiya Parambil; Muraleedharan, Pillathu Moolayil. |
| The northern Arabian Sea hosts a winter chlorophyll bloom, triggered by convective overturning in response to cold and dry northeasterly monsoon winds. Previous studies of interannual variations of this bloom only relied on a couple of years of data and reached no consensus on the associated processes. The current study aims at identifying these processes using both similar to 10 years of observations (including remotely sensed chlorophyll data and physical parameters derived from Argo data) and a 20-year-long coupled biophysical ocean model simulation. Despite discrepancies in the estimated bloom amplitude, the six different remotely sensed chlorophyll products analysed in this study display a good phase agreement at seasonal and interannual timescales.... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50625/51332.pdf |
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| Registros recuperados: 25 | |
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