Japan Agency for Marine-Earth Science and Technology

Global Long-wavelength Body-wave Catalog (GLoBoCat) for Lower Mantle P and S Wave Travel Times

Long period seismic body wave travel times are a foundational source of information regarding the Earth's interior. Manual methods provide travel time catalogs with high internal consistency, but have not kept pace with the rapid growth in teleseismic waveforms. Here we use atten...

Bayesian three-dimensional seismic travel-time tomography for active- and passive-source seismic data using physics-informed neural networks

Summary Accurate three-dimensional (3D) seismic velocity modeling through seismic travel-time tomography using both active- and passive-source data provides critical underpinning models for seismicity monitoring and hazard assessment. Because travel-time tomography is an inherent...

Fourier Neural Operator-based surrogate modeling of offshore tsunami propagation and its application to rapid tsunami source inversion

The accurate and rapid estimation of tsunami sources immediately after an earthquake is essential for real-time tsunami forecasting. Recent advances in offshore tsunami observation networks have made it increasingly feasible to estimate tsunami sources from observed waveforms usi...

Observed weakening of the Kuroshio driven by the East Asian winter monsoon under ongoing climate warming

Abstract Western boundary currents are generally thought to respond to global warming through basin-scale wind forcing and ocean stratification, yet the role of local winds remains unclear. Here, we investigate changes in the Kuroshio under ongoing climate warming using satellite...

The Climate Model Output Rewriter (CMOR)

Features User input files can now override the source, experiment, and institution global-attribute values when those attributes are not required by the controlled vocabulary. (#988, #995) Added CMIP7 site dimension examples for Python, Fortran, and C, including their generated N...

Tsunami excitation by localized subsidence associated with crater formation: a numerical case study for the October 2023 Sofu Seamount event

Abstract The October 2023 tsunami from Sofu Seamount showed large amplitudes relative to the associated seismic activity, suggesting atypical non-tectonic source processes. Comparisons of pre- and post-event bathymetric data revealed substantial topographic changes at Sofu Seamou...

Taxonomic study of the family Pedicellasteridae (Asteroidea: Forcipulatida) from Japanese waters, with descriptions of two new species and one new record

Two new deep-sea species of the family Pedicellasteridae from Japanese waters – Ampheraster phantasma sp. n. and Anteliaster seisuiae sp. n. – are described. These new species represent the first discovery of the genera Ampheraster and Anteliaster from this region. We also report...

The parent bodies of Ryugu and Ivuna formed before those of other carbonaceous chondrites

Most carbonaceous chondrite (CC) meteorites contain abundant chondrules, millimeter-scale spherical inclusions of previously molten material. Ivuna-type carbonaceous chondrites (CIs) do not contain chondrules, nor do samples of the carbonaceous asteroid Ryugu. CIs and Ryugu share...

Diffusional earthquakes and their slip-distance scaling

Abstract The final size of an earthquake typically cannot be predicted from its ongoing seismic radiation. Expanding observations reveal distinct exceptions, such as slow earthquakes, injection-induced seismicity, and natural earthquake swarms, in which fault slip has an upper bo...

Photo‐Switchable Molecular Module Programming PET Biodegradation in Aquatic Environments

ABSTRACT Plastics face a durability paradox where their utility causes environmental intractability. We resolve this by embedding a photo‐controlled molecular module, a pyrrolidone carboxylamide derived from itaconic acid, directly into the polymer backbone. While stable during u...

Koopman analysis of sea surface temperature with a signature kernel

We develop a trajectory-based Koopman method for sea surface temperature (SST) that lifts annual SST segments using a signature kernel—a reproducing kernel Hilbert space kernel that compares paths via iterated-integral features—and learns the one-year shift operator. By operating...

Feasibility to detect rapid change and disappearance of seagrass: Lessons from nearly 80 years of vegetation change in the Ako, Seto Inland Sea, Japan

Abstract. Seagrass meadows provide essential ecosystem services but are declining globally, creating an urgent need for continuous monitoring and management. However, the high cost of commercial satellite imagery and field surveys limits sustained observation, highlighting the ne...

Emerging nitrogen-driven urban atmosphere control on aerosol iron dissolution for biogeochemical cycles

Iron (Fe) is a critical micronutrient regulating marine productivity and the global carbon cycle, yet its atmospheric dissolution mechanisms remain debated for biogeochemical cycle. The prevailing “iron-sulfur coupling” paradigm has traditionally explained proton-promoted dissolu...

Direct speciation of ultra-trace platinum in marine ferromanganese oxides by wavelength-dispersive XAFS

Abstract Ultra-trace platinum (Pt) in marine ferromanganese oxides (FMOs) has remained inaccessible to direct XAFS analysis because of its extremely low abundance and severe interferences from co-existing elements. We achieved the first direct speciation of Pt at the 1 μg g−1 lev...

Deep learning to monitor the deep sea: a category‐oriented automated framework for quantifying animal behavior at hydrothermal vents

Abstract Increasing evidences show that fauna living in deep‐sea ecosystems exhibit various complex behaviors that remain understudied. Although several in situ observatories have been set up around the globe, the use of their imagery data to gain insights into animal behavior ac...

CMIP6 biogeochemical models under-represent the deep chlorophyll maximum and diverge in how they express it: a regime-stratified BGC-Argo evaluation in the North Pacific

Abstract. Surface chlorophyll, the variable most directly linked to satellite ocean colour, is widely used to evaluate marine biogeochemical models, yet it cannot by itself reveal how chlorophyll is distributed through the water column. Using Biogeochemical-Argo (BGC-Argo) chloro...

Hysteresis and irreversibility in permafrost physical response to increase and decrease of CO 2 emissions

Abstract. Boreal permafrost over the Northern Hemisphere high latitudes, defined as areas where the ground temperature is below 0 °C for two or more years, stores more than twice as much carbon as the atmosphere. Therefore, thawing of the permafrost, a tipping element, due to glo...

Measuring Ocean Surface Waves

Abstract Propagating waves on the ocean surface can be represented as a stochastic process whose statistics are characterized by a spectrum. This paper reviews methods for measuring the wave spectrum and related quantities. Observations begin by sensing fluid dynamical properties...

Evidence for latent regularities in echolocation-guided flight behaviour of bats

Abstract Echolocating bats navigate complex environments with remarkable agility, yet it remains unclear whether their flight trajectories are governed by reproducible internal policies shared within a species and across the controlled environments examined. To address this quest...

Middle atmosphere chemical and dynamical effects in the CCMI-2022 stratospheric aerosol injection scenario

Abstract. Stratospheric aerosol injection (SAI) could slow surface warming, however, potential side effects include changes in stratospheric ozone and changes in regional surface temperatures and precipitation resulting from tropical lower stratospheric warming. Previous multi-mo...