Uranus's Northern Polar Cap in 2014

In October and November 2014, spectra covering the 1.436 – 1.863-μm wavelength range from the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope showed the presence of a vast bright North polar cap on Uranus, extending northward from about 40ºN and at all longitudes observed. The feature, first detected in August 2014 from Keck telescope images, has a morphology very similar to the southern polar cap that was seen to fade before the 2007 equinox. At strong methane-absorbing wavelengths (for which only the high troposphere or stratosphere is sampled) the feature is not visible, indicating that it is not a stratospheric phenomenon. We show that the observed northern bright polar cap results mainly from a decrease in the tropospheric methane mixing ratio, rather than from a possible latitudinal variation of the optical properties or abundance of aerosol, implying an increase in polar downwelling near the tropopause level

Probable detection of hydrogen sulphide (H₂S) in Neptune’s atmosphere

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Latitudinal Variations in Methane Abundance, Aerosol Opacity and Aerosol Scattering Efficiency in Neptune's Atmosphere Determined From VLT/MUSE

Spectral observations of Neptune made in 2019 with the Multi Unit Spectroscopic Explorer (MUSE) instrument at the Very Large Telescope (VLT) in Chile have been analyzed to determine the spatial variation of aerosol scattering properties and methane abundance in Neptune's atmosphere. The darkening of the South Polar Wave at ∼60°S, and dark spots such as the Voyager 2 Great Dark Spot is concluded to be due to a spectrally dependent darkening (λ 650 nm. We find the properties of an overlying methane/haze aerosol layer at ∼2 bar are, to first-order, invariant with latitude, while variations in the opacity of an upper tropospheric haze layer reproduce the observed reflectivity at methane-absorbing wavelengths, with higher abundances found at the equator and also in a narrow “zone” at 80°S. Finally, we find the mean abundance of methane below its condensation level to be 6%–7% at the equator reducing to ∼3% south of ∼25°S, although the absolute abundances are model dependent.We are grateful to the United Kingdom Science and Technology Facilities Council for funding this research (Irwin: ST/S000461/1, Teanby: ST/R000980/1). Glenn Orton was supported by funding to the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Leigh Fletcher and Mike Roman were supported by a European Research Council Consolidator Grant (under the European Union's Horizon 2020 research and innovation programme, grant agreement no. 723890) at the University of Leicester. Santiago Pérez-Hoyos and Agustin Sánchez-Lavega are supported by the Spanish project PID2019-109467GB-I00 (MINECO/FEDER, UE), Elkartek21/87 KK-2021/00061 and Grupos Gobierno Vasco IT-1742-22

DIE EINSCHRÄNKUNG DER VERWENDUNG DER GLAGOLIZA AUF DER SYNODE VON ZADAR 1460

U radu se prikazuje odluka Zadarske sinode od 4. prosinca 1460. na kojoj je nadbiskup Mafej Vallaresso pokušao suzbiti upotrebu liturgije na crkvenoslavenskom jeziku hrvatske redakcije (lingua sclava). Sinodalni akti nisu danas sačuvani već je dostupan samo jedan dio sinodalnog kanona u dvije verzije. Originalnu verziju donosi Carlo F. Bianchi, dok je drugu, neznatno izmijenjenu, pribilježio Ivan Zanotti – Tanzlingher. Poslije interpretcije i konzultacije mjerodavnih vrela zaključuje se kako sinodalna odredba nije posve dokidala liturgijska slavlja na hrvatskom jeziku nego je samo na sinodi poduzet pothvat prostornog i vremenskog suzbijanja »glagoljaške liturgije«. Zadarski su nadbiskupi pokušavali tijekom XVI. stoljeća suzbiti glagoljicu na teritoriju nadbiskupije, ali – kako to pokazuju dostupna vrela – nisu imali znatnijeg uspjeha.In this short discussion author analyzes decisions of the Zadar synod that was held on 4th December 1460. At this diocese council archbishop Mafeo Vallaresso tried to suppress local custom of having the holy service in Church-Slavonic language. The acts from this synod unfortunately are not completely preserved but only one article De celebratione missarum et elebrandi divina official today is known in two versions. The first, and presumably original, version was brought to us by Carlo F. Bianchi, and the second one, just slightly modified, was noted by Ivan Zanotti-Tanzlingher. The both notes deliver basically the same information, and differ only regarding the beginning of this act. Archbishop Vallaresso deeply influenced ecclesiastical life of his diocese at his time: he renovated archbishopric palace, ordered a new bell for the cathedral’s bell tower, and restored organ in the cathedral of St. Anastasia. Still, even though he was a typical renaissance man, he did not care much about the specific local tradition of Zadar and deeply rooted Croatian language. Moreover, through the synod he tried to restrain Glagolitic liturgy only to two town churches: St. Donatus (Holy Trinity) and St. Mary the Great. Similarly, a century later, archbishops of the sixteenth century also tried to suppress Glagolitic script in Zadar, for example on the synods of 1566 and 1594. However, in spite of their endeavors, as it is clearly visible from the extant sources, they did not have much success, and Church Slavonic remained an integral part of local liturgy until the reform of the Second Vatican Council.In dieser kleinen Abhandlung wird die synodale Entscheidung über die Einschränkung der Liturgie in der kirchenslavischen Sprache (der kroatischen Redaktion) analysiert. Der venezianische Patrizier und der Erzbischof von Zadar, Maphäus Vallaresso (1450-1496) hat am 4. Dezember 1460 die Synode in Zadar einberufen; ihre Akten oder Entscheidungen sind nicht erhalten, nur ein kleiner Ausschnitt aus dem Kanon »De celebratione missarum et celebrandi divina officia«. Dieser ist heute in zwei Versionen zugänglich, die sich sprachlich nur geringfügig voneinander unterscheiden. Die Originalversion hat schon Carlo F. Bianchi veröffentlicht und die zweite hat Johannes Zanotti – Tanzlingher in seinem Werk Epitome synodorum dioecesis Iadrensis vermerkt. Die synodale Entscheidung versucht die Liturgie in der kirchenslavischen Sprache der kroatischen Redaktion für bestimmte Zeit nur auf zwei Kirchen in Zadar zu reduzieren: Die Kirche der Hl. Dreifaltigkeit (heute hl. Donat) und die Kirche der hl. Maria. Diese Entscheidung ließ sich nicht verwirklichen, da die Liturgie in lingua slava (d. h. in kroatischer Sprache) eine lange Tradition hat und in allen Pfarreien verbreitet war. Die Erzbischöfe von Zadar, Mutius Callinus (1555-1566) und auch Aloysius Molinus (1592-1595) haben diese Entscheidung auf den Synoden 1566 und 1594 noch einmal verbindlich erklärt; die Versuche sind gescheitert. Erzbischof Oktavian Garzzadoro (1623-1644), der aus gesundheitlichen Gründen Papst Urban VIII. um die Entbindung von den Pflichten bat, fügte seiner Begründung hinzu, dass er die Sprache der Gläubigen seines Bistums nicht versteht. Dies ist ein klarer Beweis dafür, dass in Zadar die Bevölkerung kroatisch gesprochen hat und die Liturgie bis zur Reform des II. Vatikanischen Konzils in der Landessprache gefeiert wurde

An intense narrow equatorial jet in Jupiter’s lower stratosphere observed by JWST

The atmosphere of Jupiter has east–west zonal jets that alternate as a function of latitude as tracked by cloud motions at tropospheric levels. Above and below the cold tropopause at ~100 mbar, the equatorial atmosphere is covered by hazes at levels where thermal infrared observations used to characterize the dynamics of the stratosphere lose part of their sensitivity. James Webb Space Telescope observations of Jupiter in July 2022 show these hazes in higher detail than ever before and reveal the presence of an intense (140 m s−1) equatorial jet at 100–200 mbar (70 m s−1 faster than the zonal winds at the cloud level) that is confined to ±3° of the equator and is located below stratospheric thermal oscillations that extend at least from 0.1 to 40 mbar and repeat in multiyear cycles. This suggests that the new jet is a deep part of Jupiter’s Equatorial Stratospheric Oscillation and may therefore vary in strength over time.JWST-ERS-01373, NASA/ESA Hubble Space Telescope programmes no. 16913, 15502 and 16790, PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/, Grupos Gobierno Vasco IT1742-22. I.d.; European Research Council Consolidator Grant (under the European Union’s Horizon 2020 research and innovation programme, grant agreement no. 723890), STFC PhD Studentship, NASA grants 80NSSC21K1418 and 80NSSC19K0894

Colour and tropospheric cloud structure of Jupiter from MUSE/VLT: Retrieving a universal chromophore

International audienceRecent work by Sromovsky et al. (2017) suggested that all red colour in Jupiter’s atmosphere could be explained by a single colour-carrying compound, a so-called ‘universal chromophore’. We tested this hypothesis on ground-based spectroscopic observations in the visible and near-infrared (480–930 nm) from the VLT/MUSE instrument between 2014 and 2018, retrieving a chromophore absorption spectrum directly from the North Equatorial Belt, and applying it to model spatial variations in colour, tropospheric cloud and haze structure on Jupiter. We found that we could model both the belts and the Great Red Spot of Jupiter using the same chromophore compound, but that this chromophore must exhibit a steeper blue-absorption gradient than the proposed chromophore of Carlson et al. (2016). We retrieved this chromophore to be located no deeper than 0.2 &plusmn 0.1bars in the Great Red Spot and O.7 &plusmn 0.1bars elsewhere on Jupiter. However, we also identified some spectral variability between 510 nm and 540 nm that could not be accounted for by a universal chromophore. In addition, we retrieved a thick, global cloud layer at 1.4 &plusmn 0.3 bars that was relatively spatially invariant in altitude across Jupiter. We found that this cloud layer was best characterised by a real refractive index close to that of ammonia ice in the belts and the Great Red Spot, and poorly characterised by a real refractive index of 1.6 or greater. This may be the result of ammonia cloud at higher altitude obscuring a deeper cloud layer of unknown composition

美國與孫逸仙〈1911-1925〉

Microphysical simulations have been performed to constrain the formation and structure of haze in Uranus's atmosphere. These simulations were coupled to a radiative-transfer code to fit observations performed by the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT) and by the Wide Field Camera 3 (WFC3) of the Hubble Space Telescope (HST) in 2014. Our simulations yield an effective radius of ∼0.2 μm for the haze particles in the tropopause and a density of ∼2.9 particles per cm3. Our simulations also provide an estimate for the haze production rate in the stratosphere of between ∼3.10−16 and 3.10−15 kg m−2 s−1, about 100 times smaller than that found in Titan's atmosphere (e.g. Rannou et al., 2004). This range of values is very similar to that derived by Pollack et al. (1987) from Voyager-2 observations in 1986, suggesting microphysical timescales greater than the elapsed time between these observations (28 years, or 1/3 of a Uranian year). This result is in agreement with analyses performed with our microphysical model that show timescales for haze particles to grow and settle out to be >∼30 years at pressure levels >0.1 bar. However, these timescales are too big to explain the observed variations in the haze structure over Uranus's northern hemisphere after 2007 equinox (e.g. de Pater et al., 2015). This indicates that dynamics may be the main factor controlling the spatial and temporal distribution of the haze over the poles. A meridional stratospheric transport of haze particles with winds velocities >∼0.025 m s−1 would result in dynamics timescales shorter than 30 years and thus may explain the observed variations in the haze structure

Disruption of Saturn’s quasi-periodic equatorial oscillation by the great northern storm

The equatorial middle atmospheres of the Earth1, Jupiter2 and Saturn3,4 all exhibit a remarkably similar phenomenon—a vertical, cyclic pattern of alternating temperatures and zonal (east–west) wind regimes that propagate slowly downwards with a well-defined multi-year period. Earth’s quasi-biennial oscillation (QBO) (observed in the lower stratospheric winds with an average period of 28 months) is one of the most regular, repeatable cycles exhibited by our climate system1,5,6, and yet recent work has shown that this regularity can be disrupted by events occurring far away from the equatorial region, an example of a phenomenon known as atmospheric teleconnection7,8. Here, we reveal that Saturn’s equatorial quasi-periodic oscillation (QPO) (with an ~15-year period3,9) can also be dramatically perturbed. An intense springtime storm erupted at Saturn’s northern mid-latitudes in December 201010,11,12, spawning a gigantic hot vortex in the stratosphere at 40° N that persisted for three years13. Far from the storm, the Cassini temperature measurements showed a dramatic ~10 K cooling in the 0.5–5 mbar range across the entire equatorial region, disrupting the regular QPO pattern and significantly altering the middle-atmospheric wind structure, suggesting an injection of westward momentum into the equatorial wind system from waves generated by the northern storm. Hence, as on Earth, meteorological activity at mid-latitudes can have a profound effect on the regular atmospheric cycles in Saturn’s tropics, demonstrating that waves can provide horizontal teleconnections between the phenomena shaping the middle atmospheres of giant planets