This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are
Doctor honoris causa: David Jou i Mirabent: Parlaments de la cerimònia d’investidura llegits el dia 1o de desembre de 2014 a l’Aula Magna Modest Prats de la UdG: Girona, desembre de 2014
Universitat de Girona. Servei de Publicacions eBooks, 2015
Satellite-tracked drifting buoys are useful for sampling sea-surface currents. Standard drifting ... more Satellite-tracked drifting buoys are useful for sampling sea-surface currents. Standard drifting buoys have drogues centred at a depth of 15 m, a fundamental element that guarantees that the direct wind force on the buoy is much smaller than the drag on the anchor. When a drifter loses its drogue, it no longer becomes a good tracker of the surface currents, hence the relevance of identifying when this happens. Here we propose a spectral-based approach to analyse drifter velocity data so as to detect when a drifter loses its drogue without the need of concurrent wind data. The method, applied to data obtained during the SPURS 2013 cruise, shows a substantial increase in the band-passed velocity energy at the time the drifter loses its drogue, as deduced with an independent method that considers the temporal change of the correlation between wind and positioning data. The results are very promising, pointing at a new method that can detect drogue loss from a relatively simple analysis of positioning data.
Discurs de presentació del Dr. David Jou i Mirabent, a càrrec del Dr. Xavier Casamitjana i la Dra. Elena Roget
El doctor David Jou i Mirabent va rebre el titol de Doctor honoris causa de la Universitat de Gir... more El doctor David Jou i Mirabent va rebre el titol de Doctor honoris causa de la Universitat de Girona, a proposta del Departament de Fisica. L’elogi dels merits del nou doctor va anar a carrec de dos professors d’aquest departament, la Dra. Elena Roget i el Dr. Xavier Casamitjana
Special volume: Advances in Spanish physical oceanography. Scientia Marina 76(Suppl.1) 2012.-- 13... more Special volume: Advances in Spanish physical oceanography. Scientia Marina 76(Suppl.1) 2012.-- 13 pages, 12 figures, 1 table[EN] Turbidity, CTD, and temperature and shear microstructure data recorded along a 25 km transect from 8 to 69 m depth across the Ebro Delta shelf (northwestern Mediterranean) are presented. The water column was stratified and prior to the campaign the regional southwest flow was measured to have superimposed diurnal and sub-inertial components. The bottom boundary layer (BBL) at all stations deeper than 20 m has a vertical extension of 3 to 9 m, increasing to 12 m at the deeper stations and even to 14 m at a station at 45 m depth outside the studied transect. The law of the wall was identified at almost all stations with an extension ranging from 40% to 100% of that of the BBL. At some stations high dissipation rates were found in the interior of the bottom layer. The study shows the correspondence between the turbidity contents and the local mixing processes...
The main physical long-scale processes occurring in Lake Banyoles are reviewed as a tribute to Pr... more The main physical long-scale processes occurring in Lake Banyoles are reviewed as a tribute to Prof. Margalef. These processes include the water fluxes below the surface of the lake, the behavior of the sediment in suspension in the basins, the heat fluxes at the surface and at the bottom layers, the internal seiching, the formation of a baroclinic current due to differences in cooling between the two lobes, the mixing dynamics, the meromictic behavior of some of the basins and the formation and dynamics of hydrothermal plumes Keywords: physical processes, sediment in suspension, internal seiches, baroclinic currents, hydrothermal plumes RESUMEN Los principales procesos físicos de gran escala que tienen lugar en le Lago de Banyotes son revisados como tributo al Profesor Margalef. Estos procesos incluyen los flujos de agua bajo la superficie del lago, el comportamiento del sedimento en suspensión en las cubetas, los flujos de calor en la superficie y en el fondo, las secas internas y la formación
BAROCLYNIC CURRENTS AND INTEKNAL SEICHES IN BANYOLES LAKE (SPAIN) Wind induced phenomena as the s... more BAROCLYNIC CURRENTS AND INTEKNAL SEICHES IN BANYOLES LAKE (SPAIN) Wind induced phenomena as the setup of the therrnocline and the consequent interna1 seiches have been recorded in the southern lobe of Banyoles Lake. The observed period is in agreement with that obtained theoretically by the MortimerIDefant method. During these events-about two days-the thermocline migrated more than two meters. The Richardson number during this period «f seiches suggests that the induced shear was not the force but the direct effect of the wind. From November to April a bottom baroclinic current from north to south was also recordered. The differential heating between the two lobes is due to their significantly different depth and to the different incoming heat flux through the underground sources. This current can be observed indirectly from temperature data but also directly from the data recordered in a currentmeter too. The current is highly influenced by the wind blowing in the northsouth direction. In the central part of the lake, currents up to 12 cmls are observed. Their path, slightly inflected towards the right, seerns to be influenced by the bottom of the lake, but Coriolis force may be also important.
Statistics of microstructure patches in a sheared, strongly stratified metalimnion of Lake Banyol... more Statistics of microstructure patches in a sheared, strongly stratified metalimnion of Lake Banyoles (Catalonia, Spain), which occupied ∼40% of the total lake depth of 12 m, are analyzed. Light winds (<3 m s −1) dominated the periods of observation in late June and early July of 2009. The patch sizes h p and the corresponding patch Thorpe scales L Tp were identified using profiling measurements of temperature microstructure and small-scale shear. The distribution of h p was found to be lognormal with mean and median values of 0.69 m and 0.50 m respectively. The distribution of L Tp within the patches was also fitted to a lognormal model and the mean and median values found to be close to 0.1 m. The probability distribution of the ratio L Tp /h p was approximated by the Weibull probability model with a shape parameter c w ≈ 2, and also by beta probability distribution. For h p > 0.25 m, the ratio L Tp /h p depends on the patch Richardson and mixing Reynolds numbers following the parameterization of Lozovatsky and Fernando (2002). Analysis of the dynamics of mixing reveals that averaged vertical diffusivities ranged between ∼1 × 10 −4 m 2 s −1 and ∼5 × 10 −5 m 2 s −1 , depending on the phase of the internal waves. Episodic wind gusts (wind speed above 6 m s −1) transfer ∼1.6% of the wind energy to the metalimnion and ∼0.7% to the hypolimnion, generating large microstructure patches with h p of several meters.
Tellus A: Dynamic Meteorology and Oceanography, 2018
Changes in the surface air diurnal temperature range (DTR) have been highlighted by the Intergove... more Changes in the surface air diurnal temperature range (DTR) have been highlighted by the Intergovernmental Panel on Climate Change as critical uncertainties in climate change studies. Due to global and local factors, the regional climate in the Aral Sea region is changing intensively, providing a good case study to give a detailed description of the DTR trend and its spatial variability. Results are based on data from 33 stations at the RIHMI-WDC from 1991 to 2010. The values of DTR in the region range between about 3 C and 18 C, with the maxima values being observed in spring and summer. The largest differences between the two decades of the annual mean DTR are observed at the stations closest to the pre-desiccation state of the lake shoreline, especially in the south (0.6 C dec À1). To the west of the Aral Sea, where the lakeshore has receded less, these differences are also expectedly high considering the decrease in the thermal inertia of the remaining lake (0.4 C dec À1). To the northeast of the lake, the decadal differences of the annual mean DTR were not significant, but decadal differences of the seasonal DTR were large from February to April (-0.4 C dec À1) coinciding with the season when the decadal differences of the mean local temperature is of 2 C dec À1. In the south, where the artificial Sarygamysh Lake expanded during the studied period, the decadal difference of the annual mean DTR is negative. The increase in the mean temperature of all the stations between the two decades is of 0.5 C dec À1. From August to October, in the southern and the southeastern parts of the Aral Sea, the increase of the maximum daily temperatures was about 0.1 C dec À1 larger than the increase of the mean temperatures.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Studying the impact of large lake desiccation on the accuracy of numerical description of meteorological fields (a case study for the Aral Sea)
Russian Meteorology and Hydrology, 2014
Described is the impact of the Aral Sea desiccation on the local climate and the impact of its nu... more Described is the impact of the Aral Sea desiccation on the local climate and the impact of its numerical prediction in the region. Presented is the analysis of two series of numerical experiments with the WRF-ARW model (numerical prediction and weather research) with the spatial resolution of 5 km and 28 σ-surfaces along the vertical up to the level of 50 hPa for the Aral Sea region. In the first series of forecasts for January and July 2009, underlying surface parameters from the MODIS database are used. In these series the sea surface mask corresponds to the Aral Sea configuration in the 1970s. In another group of experiments, the characteristics of the underlying surface of the Aral Sea area are replaced by the respective characteristics of the surrounding land. To study the effects of variations of surface properties, air temperature, humidity, cloudiness, precipitation, and wind are analyzed. It is demonstrated that if the Aral Sea is assumed to be absent in the model, this results in the significant strengthening of the continentality of regional climate and in the increase in the forecast skill scores. The supposition is made that the regular (at least each 3–5 years) update of global databases with the description of underlying surface properties due to the climate change can result in the considerable increase in the accuracy of numerical prediction and climate change modeling.
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