Eguzki-sistemako planeta erraldoien atmosfera

Haize-korronte izugarriak dira, Eguzki-sistemako planeta erraldoien (Jupiter, Saturno, Urano eta Neptuno) atmosferen ezaugarri nagusia. Saturnoren kasuan, 500 m/s-ko abiadura izatera hel daitezke korronte hauek. Hauen jatorria ez da ondo ezagutzen oraindik eta izatez beraiek dira astrofisikarientzako erronkarik handienetako bat da. Lan honetan, planeta erraldoien atmosfera aztertuko da hodei mailan gertatzen diren haizeen zirkulazio orokorra kontuan hartuz

Evaluation of the theoretical, technical and economic potential of industrial waste heat recovery in the Basque Country

Industrial waste heat recovery shows significant potential for increasing energy efficiency in industry. However, to design strategies that exploit this potential, it is necessary to have data about the quantity and characteristics of industrial waste heat flows. This information is not always readily available and many companies do not even have a systematic record of these energy flows. Hence, bottom-up methodologies to estimate that recovery potential by means of key transfer figures are useful tools within this field. In the present article, four different methods are applied to determine the industrial waste heat recovery potential in the Autonomous Community of the Basque Country (northern Spain), an energy-intensive industrial region with large energy dependency from the outside. Besides, the analysis of the economic viability of the industrial waste heat recovery is essential, because it determines the final adoption of energy efficiency measures. For that aim, the authors develop an easy-to-apply bottom-up methodology to carry out an assessment for the economic potential of the estimated industrial waste heat at different temperature levels. This method is applied to 129 companies, whose potentials are characterized and discussed. The obtained results show that, for waste heat streams above 400 ?C, more than 90% of the studied companies present payback periods below five years. For those industries with waste heat temperatures below 200 ?C, the ratio decreases to around 40%, still a noticeable value. The estimations show a significant opportunity to implement solutions to recover this wasted energy, especially in the iron and steel sector and the petrochemical industry. The development of public policies that encourage these measurements would be also beneficial.The authors would like to acknowledge the Spanish Ministry of Science and Innovation (MICINN) for funding through the SweetTES research project (RTI 2018099557BC22)

Convective storms in closed cyclones in Jupiter: (II) numerical modeling

On May 31, 2020 a convective storm appeared in one small cyclone in the South Temperate Belt (STB) of Jupiter. The storm, nicknamed as Clyde's Spot, had an explosive start and quickly diminished in activity in a few days. However, it left a highly turbulent cyclone as a remnant that evolved to become a turbulent segment of the STB in a time-scale of one year. A very similar storm erupted on August 7, 2021 in another cyclone of the STB with a similar initial phenomenology. In both cases, the outbreaks started in cyclones that were the result of the merger of pre-existing vortices. In a previous paper we presented an observational study of these storms compared with a similar cyclonic convective system observed during the Voyager 2 flyby [Hueso et al., Convective storms in closed cyclones in Jupiter's South Temperate Belt: (I) Observations, Icarus, 380, 2022]. Here we present numerical simulations of these vortices and storms with the Explicit Planetary Isentropic-Coordinate (EPIC) numerical model. We simulate mergers of cyclones in Jupiter's STB and investigate the deep structure of the resulting cyclone and its capability to uplift material from the water condensation level. Convection is introduced in the model imposing heating sources whose vertical extent, horizontal size and duration are free parameters that we explore. Our simulations reproduce the cloud field of both storms after short episodes of a few hours of intense con-vection. The evolution of the morphology of the convective cyclone after the convective pulse stopped shows a strong relation between the convective energy released and the initial vorticity in the cyclone. Similar results are obtained for the cyclonic storm observed during the Voyager 2 flyby. We also compare our simulations of these storms with numerical simulations of a storm that developed in the STB in 2018 inside an elongated cyclone known as the South Temperate Belt Ghost [Inurrigarro et al., Observations and numerical modelling of a convective disturbance in a large-scale cyclone in Jupiter's South Temperate Belt, Icarus, 336, 2020]. In addition, we also simulate one of the large-scale storms that develop in the South Equatorial Belt comparing our simulations with Voyager 1 observations of one of those events. From these simulations, we establish a relative scale of energies associated to these convective storms. As coherent cyclones isolate the local atmosphere from their surroundings, we propose that the availability of condensables inside closed cyclones limits the duration of active convection, allowing larger convective outbursts in larger cyclones. Our simulations of the short and intense convective pulse associated to the 2020 and 2021 STB suggest a minimum local water abundance of 1.0-1.2 times solar at the location of the storms. The lower number considers a significant contribution of ammonia condensation, and the larger number considers only water moist convection with a negligible role of ammonia.This work has been supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1366-19. PI acknowledges a PhD scholarship from Gobierno Vasco

A planetary-scale disturbance in a long living three vortex coupled system in Saturn's atmosphere

The zonal wind profile of Saturn has a unique structure at 60°N with a double-peaked jet that reaches maximum zonal velocities close to 100 ms−1. In this region, a singular group of vortices consisting of a cyclone surrounded by two anticyclones was active since 2012 until the time of this report. Our observation demonstrates that vortices in Saturn can be long-lived. The three-vortex system drifts at u = 69.0 ± 1.6 ms−1, similar to the speed of the local wind. Local motions reveal that the relative vorticity of the vortices comprising the system is ∼2–3 times the ambient zonal vorticity. In May 2015, a disturbance developed at the location of the triple vortex system, and expanded eastwards covering in two months a third of the latitudinal circle, but leaving the vortices essentially unchanged. At the time of the onset of the disturbance, a fourth vortex was present at 55°N, south of the three vortices and the evolution of the disturbance proved to be linked to the motion of this vortex. Measurements of local motions of the disturbed region show that cloud features moved essentially at the local wind speeds, suggesting that the disturbance consisted of passively advecting clouds generated by the interaction of the triple vortex system with the fourth vortex to the south. Nonlinear simulations are able to reproduce the stability and longevity of the triple vortex system under low vertical wind shear and high static stability in the upper troposphere of Saturn.This work was supported by the Spanish MICIIN projects AYA2015-65041-P (MINECO/FEDER, UE), Grupos Gobierno Vasco IT-765-13, and UFI11/55 from UPV/EHU. EGM is supported by the Serra Hunter Programme, Generalitat de Catalunya. A. Simon, K. Sayanagi and M.H. Wong were supported by a NASA Cassini Data Analysisgrant (NNX15AD33G and NNX15AD34G). We acknowledge the three orbits assigned by the Director Discretionary time from HST for this research (DD Program 14064, IP A. Sánchez-Lavega). We are very grateful to amateur astronomers contributing with their images to open databases such as PVOL (http://pvol2.ehu.eus/) and ALPO-Japan (http://alpo-j.asahikawa-med.ac.jp/)

Eguzki-sistemako planeta erraldoien atmosfera

Haize-korronte izugarriak dira, Eguzki-sistemako planeta erraldoien (Jupiter, Saturno, Urano eta Neptuno) atmosferen ezaugarri nagusia. Saturnoren kasuan, 500 m/s-ko abiadura izatera hel daitezke korronte hauek. Hauen jatorria ez da ondo ezagutzen oraindik eta izatez beraiek dira astrofisikarientzako erronkarik handienetako bat da. Lan honetan, planeta erraldoien atmosfera aztertuko da hodei mailan gertatzen diren haizeen zirkulazio orokorra kontuan hartuz

Jupiter's third largest and longest-lived oval: Color changes and dynamics

The transition region between the North Equatorial Band (NEBn) and North Tropical Zone (NTrZ) in Jupiter is home to convective storms, systems of cyclones and anticyclones and atmospheric waves. Zonal winds are weak but have a strong latitudinal shear allowing the formation of cyclones (typically dark) and anticyclones (typically white) that remain close in latitude. A large anticyclone formed in the year 2006 at planetographic latitude 19°N and persists since then after a complex dynamic history, being possibly the third longest-lived oval in the planet after Jupiter's Great Red Spot and oval BA. This anticyclone has experienced close interactions with other ovals, merging with another oval in February 2013; it has also experienced color changes, from white to red (September 2013) and back to white with an external red ring (2015–2016). The oval survived the effects of the closely located North Temperate Belt Disturbance, which occurred in October 2016 and fully covered the oval, rendering it unobservable for a short time. When it became visible again at its expected longitude from its previous longitudinal track, it reappeared as a white large oval keeping this color and the same morphology since 2017 at least until the onset of the new convective disturbance in Jupiter's North Temperate Belt in August 2020. Here we describe the historic evolution of the properties of this oval. We use JunoCam and Hubble Space Telescope (HST) images to measure its size obtaining a mean value of (10,500 ± 1000) x (5,800 ± 600) km2 and its internal rotation finding a value of -(2 ± 1)·10−5 s−1 for its mean relative vorticity. We also used HST and PlanetCam-UPV/EHU multi-wavelength observations to characterize its color changes and Junocam images to unveil its detailed structure. The color and the altitude-opacity indices show that the oval is higher and has redder clouds than its environment but has lower cloud tops than other large ovals like the GRS, and it is less red than the GRS and oval BA. We show that in spite of the dramatic environmental changes suffered by the oval during all these years, its main characteristics are stable in time and therefore must be related with the atmospheric dynamics below the observable cloud decks.This work has been supported by the Spanish projects AYA2015-65041-P, PID2019-109467GB-100 (MINECO/FEDER, UE) and Grupos Gobierno Vasco IT1366-19. P. Iñurrigarro acknowledges a PhD scholarship from Gobierno Vasco. I. Ordonez-Etxeberria's was supported by contract from Europlanet 2024 RI. Europlanet 2024 RI has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149. This work used data acquired from the NASA/ESA HST Space Telescope, associated with OPAL program (PI: Simon, GO13937) and programs GO/DD 13067 (PI: Glenn Schneider), GO 14661 (PI: Michael Wong) and GO 14839 (PI: Imke de Pater), and archived by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5–26,555. HST/OPAL maps are available at http://dx.doi.org/10.17909/T9G593. Junocam images are available at https://www.missionjuno.swri.edu/junocam/ and at the PDS Cartography and Imaging Sciences Node at: https://pds-imaging.jpl.nasa.gov/volumes/juno.html. This research has made use of the USGS Integrated Software for Imagers and Spectrometers (ISIS). PlanetCam observations were collected at the Centro Astronómico Hispánico en Andalucía (CAHA), operated jointly by the Instituto de Astrofisica de Andalucia (CSIC) and the Andalusian Universities (Junta de Andalucía) and are available on request from the instrument PI Agustín Sánchez-Lavega. Amateur images are available at the PVOL website https://pvol2.ehu.eus. LAIA and PLIA can be downloaded from: http://www.ajax.ehu.es/Software/laia.html and http://www.ajax.ehu.es/PLIA respectively. The software PICV is available at zenodo with doi: https://doi.org/10.5281/zenodo.4312674