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The deformation of the Earth's crust in Antarctica caused by Glacial Isostatic Adjustment (GIA) is highly dependent on the melting history of ice and the viscoelastic properties of the mantle. However, geodetic observations, including Global Navigation Satellite System (GNSS) measurements, are essential in constraining GIA model parameters.The Japanese Antarctic Research Expedition has conducted GNSS observations and absolute gravity measurements for over 20 years along the coast of Lützow-Holm Bay in East Antarctica, mainly at Syowa Station. This study aims to examine the geodetic signals associated with GIA from the observations made along the coast of Lützow-Holm Bay. Furthermore, the study involves numerical simulations of the signals based on the recently reported rapid ice thinning in this region during the mid-Holocene (Kawamata et al., 2020, QSR).According to Kawamata's paper, the target region underwent a rapid ice thinning of over 400 m from about 9 to 6 ka, as evidenced by geomorphological surveys and surface exposure ages. The representative deglaciation models, such as ICE-6G, do not incorporate this rapid thinning process. Therefore, the study examines the variability of the geodetic signals using the ice history, including rapid thinning. The predictions indicate that the modified ice history produces consistent results with the observations, thus supporting the occurrence of rapid ice melting during the Holocene. The results also suggest that geodetic observations can aid in constraining the ice sheet melting process in this region. Additionally, the study presents a similar analysis of gravity variations obtained from absolute gravity measurements at Syowa Station., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The National Institute of Information and Communications Technology (NICT) has developed a Sr optical lattice clock and optical ion clocks employing In+and Ca+. The centimeter-level uncertainty of site elevation is the cause of 10^(-18)-level frequency uncertainties of optical frequency standards. It is significantly important to understand frequency changes caused by solid-earth tides that often range from 10 to 20 cm in amplitude, by oceanic tidal loading, crustal deformations due to earthquakes, and ground movements with groundwater changes for the stable operation of optical atomic clocks.NICT and partners including the Geospatial Information Authority of Japan (GSI) have been jointly conducting leveling surveys and relative gravimeter observations at NICT’s headquarters in Koganei. These observations reduce the contribution of gravitational redshift to the total uncertainty of the optical lattice clock to the 10^(-19)level. With the support of National Institute of Polar Research (NIPR), absolute gravity measurements were performed in August 2019 and May 2022 to evaluate the effects of the 2011 off the Pacific coast of Tohoku Earthquake on postseismic crustal movement. The obtained absolute gravity change between the two periods was -43.8 μGal, which matches the trend of GNSS vertical movement obtained by GSI. We have introduced a Micro-g LaCoste’s gPhoneX gravimeter for continuous gravity measurements nearby the optical clocks in the end of 2021 and have started to investigate the temporal variation of the ground water level in Koganei. We will present preliminary results of these geodetic measurements., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Context. Accreting planetary-mass objects have been detected at H ��, but targeted searches have mainly resulted in non-detections. Accretion tracers in the planetary-mass regime could originate from the shock itself, making them particularly susceptible to extinction by the accreting material. High-resolution (R > 50 000) spectrographs operating at H �� should soon enable one to study how the incoming material shapes the line profile. Aims. We calculate how much the gas and dust accreting onto a planet reduce the H �� flux from the shock at the planetary surface and how they affect the line shape. We also study the absorption-modified relationship between the H �� luminosity and accretion rate. Methods. We computed the high-resolution radiative transfer of the H �� line using a one-dimensional velocity���density���temperature structure for the inflowing matter in three representative accretion geometries: spherical symmetry, polar inflow, and magnetospheric accretion. For each, we explored the wide relevant ranges of the accretion rate and planet mass. We used detailed gas opacities and carefully estimated possible dust opacities. Results. At accretion rates of ��� ��� 3 �� 10���6 MJ yr���1, gas extinction is negligible for spherical or polar inflow and at most AH �� ��� 0.5 mag for magnetospheric accretion. Up to ��� ��� 3 �� 10���4 MJ yr���1, the gas contributes AH �� ��� 4 mag. This contribution decreases with mass. We estimate realistic dust opacities at H �� to be �� ~ 0.01���10 cm2 g���1, which is 10���104 times lower than in the interstellar medium. Extinction flattens the LH �� ������ relationship, which becomes non-monotonic with a maximum luminosity LH �� ~ 10���4 L��� towards ��� ��� 10���4 MJ yr���1 for a planet mass ~10 MJ. In magnetospheric accretion, the gas can introduce features in the line profile, while the velocity gradient smears them out in other geometries. Conclusions. For a wide part of parameter space, extinction by the accreting matter should be negligible, simplifying the interpretation of observations, especially for planets in gaps. At high ���, strong absorption reduces the H �� flux, and some measurements can be interpreted as two ��� values. Highly resolved line profiles (R ~ 105) can provide (complex) constraints on the thermal and dynamical structure of the accretion flow.

PurposeTo classify central serous chorioretinopathy (CSC) by deep learning (DL) analyses of en face images of choroidal vasculature obtained by optical coherence tomography (OCT) and to analyze the regions of interest for DL from heatmaps.MethodsOne-hundred eyes were studied; 53 eyes with CSC and 47 normal eyes. Volume scans of 12×12 mm square were obtained at the same time as the OCT angiographic (OCTA) scans (Plex Elite 9000 Swept-Source OCT®, Zeiss). High-quality en face images of the choroidal vasculature of the segmentation slab of one-half of the subfoveal choroidal thickness were created for the analyses. The entire 100 en face images were divided into 80 for training (100 times) and 20 for validation. The Neural Network Console (NNC) developed by Sony and the Keras-Tensorflow backend developed by Google were used as the software for the classification with 16 layers of convolutional neural networks. The active region of the heatmap based on the feature quantity extracted by DL was also evaluated as the percentages with gradient-weighted class activation mapping implementation in Keras.ResultsIn the 20 eyes used for validation including 8 eyes with CSC, the accuracy rate of the validation was 100% (20/20) for NNC and 95% (19/20) for Keras. This difference was not significant (P=0.33). The mean active region in the heatmap image was 12.5% in CSC eyes which was significantly lower than the 79.8% in normal eyes (PConclusionsCSC can be automatically classified with high accuracy from en face images of the choroidal vasculature by DLs with different programs, convolutional layer structures, and small data sets. Heatmap analyses showed that DL focused on the area occupied by the choroidal vessels and their uniformity. We conclude that DL can help in the diagnosis of CSC.