Planetary atmosphere observation analysis

Abstract:

Abstract Jupiter is a hugely varying and diverse planet, demonstrated through spectacular changes in the cloud top appearance. However, the cloud structures which contributes to this appearance are hard to determine and are not known with certainty. A lack of in-situ observations and many unknown parameter values and numerous near-degenerate pairings within the parameter space for visible/near infrared observations of the aerosol profiles makes the problem under constrained. This work utilises several methods to alleviate these issues. Fitting simultaneously to dual viewing angle VLT/MUSE observations, using a radiative transfer algorithm, provides greater constraint to the aerosol profile than fitting to a single viewing geometry alone. To reduce the degeneracy between parameter pairings in the model, we utilise an aerosol profile with a minimised number of variable parameters by predetermining these values wherever possible. We find two clouds are needed, with a main cloud and haze layer fixed at 1.4 and 0.2 bars respectively, to successfully reproduce six years of VLT/MUSE observations (2018 - 2023), including dual angle observations of the Great Red Spot. We also retrieve an ammonia gas distribution across the disc similar to previous derived profiles, including the peak in deep volume mixing ratio at 5°N before a rapid depletion at 10°N. This cloud parameterisation successfully reproduces spectra extracted from 40°N to 40°S across the disc of Jupiter. For all locations (including the GRS) we find the material responsible for colouring Jupiter to be located in the main cloud layer (1.4 bar).

Abstract:

The modern world is increasingly computerised and, as more functionality is shifted to the edges of systems in bids to reduce latency or energy consumption, the Internet of Things (IoT) increasingly includes safety-critical systems. A typical such system is 'functionally dense,' with a time-shared processing element (PE) carrying out many tasks; we believe that they should instead be functionally sparse, with many small PEs dedicated to single tasks. We present case studies of this design approach and introduce FUNK, our effort to build the tools that will support the development of hard real-time, functionally safe systems that follow this approach.

Abstract:

Abstract The Hubble Space Telescope collected imaging data spanning the full lifetime of Neptune's dark spot NDS‐2018, which is the sixth large, persistent dark spot seen in the planet's atmosphere. Neptune's dark spots are thought to be anticyclonic vortices, although internal flows have never been directly measured to confirm their rotation. Previous reports covered the formation and evolution of the mature NDS‐2018, while here we report that the contrast weakened over the 2021 to 2022 period, while the feature rapidly drifted equatorward from 14 deg N to 6–7 deg N planetographic latitude. The persistence of the spot so close to the equator is surprising, and represents a challenge for numerical models which find anticyclones to be disrupted within 15 deg of the equator. The changing contrast of the dark spot constrains changes in the aerosols over time, but the link between dynamical and microphysical properties of dark vortices is not known. Plain Language Summary The Hubble Space Telescope collected images spanning the full lifetime of Neptune's dark spot NDS‐2018, which is the sixth large, persistent dark spot seen in the planet's atmosphere. Neptune's dark spots are thought to be high‐pressure rotating storms, although internal flows have never been directly measured to confirm the direction of their rotation. Previous reports covered the formation and evolution of the mature NDS‐2018, while here we report that the contrast weakened over the 2021 to 2022 period, while the feature rapidly drifted equatorward from 14 deg N to 6–7 deg N planetographic latitude. The persistence of the spot so close to the equator is surprising, and represents a challenge for numerical models which find these storms to be disrupted within 15 deg of the equator. The changing contrast of the dark spot provides information on changes in the cloud particles over time, but it is not known what is the link between how the storm works and what are the properties of cloud particles in the dark spots. Key Points Dark spot NDS‐2018 was observed on Neptune over its full lifespan, between 3.7 and 4.9 years In 2022, NDS‐2018 remained within 8 deg of the equator as it faded away Secondary dark features had morphologies of discrete spots in 2019–2020 and extended arms in 2022

Abstract:

Cassini observed Jupiter during its 2000–2001 gravity-assist flyby, acquiring a valuable set of Visible and Infrared Mapping Spectrometer (VIMS) observations over a wide range of viewing geometries and observing conditions. These data comprise visible and infrared spectral cubes covering the VIS channel from 0.35 to 1.05 µm and the IR channel from 0.9 to 5.1 µm. We present a calibrated catalog of these Jupiter VIMS observations,  excluding satellite-targeted observations, designed to provide a homogeneous and validated set of spectral products for future Jovian studies.Starting from the raw archive cubes, we developed a processing workflow that combines ISIS/SPICE-based geometry recovery with dedicated radiometric calibration procedures for both VIMS channels. The final products are delivered as multi-extension FITS files containing calibrated I/F spectral cubes, wavelength and FWHM vectors, and geometry backplanes for incidence, emission, and phase angles, planetocentric latitude, positive-east longitude, pixel resolution, and azimuth angle. The workflow also addresses several issues affecting the original data set, including saturation, VIS pointing-related offsets between radiometric cubes and geometric backplanes, channel-dependent dark-signal artifacts, and a subset of IR approach-phase for which the standard ISIS calibration pipeline can produce over-scaled reflected spectra.The resulting catalog provides a uniform, documented, validated, and publicly available set of Cassini/VIMS Jupiter products. By combining calibrated VIS and IR cubes with wavelength information and geometry backplanes, these products facilitate a wide range of applications in the study of Jupiter and its atmosphere.