ALBERT

Description: Outline: Overview of Hayabusa2 mission and its target asteroid Ryugu; Spectroscopic laboratory measurements under asteroid-like conditions of carbonaceous chondrites; Recent ground-based observations of carbonaceous asteroids relevant to Ryugu; Implications of meteorite spectroscopic measurements & asteroid observations for Hayabusa2s observations of Ryugu.

Description: We present x-ray characteristics of the Hard X-ray Telescopes (HXTs) on board the Hitomi (ASTRO-H) satellite. Measurements were conducted at the SPring-8 BL20B2 beamline and the ISAS/JAXA 27-m beamline.

Description: Human impacts increasingly affect the global hydrological cycle and indeed dominate hydrological changes in some regions. Hydrologists have sought to identify the human-impact-induced hydrological variations via parameterizing anthropogenic water uses in global hydrological models (GHMs). The consequently increased model complexity is likely to introduce additional uncertainty among GHMs. Here, using four GHMs, between-model uncertainties are quantified in terms of the ratio of signal to noise (SNR) for average river flow during 1971-2000 simulated in two experiments, with representation of human impacts (VARSOC) and without (NOSOC). It is the first quantitative investigation of between-model uncertainty resulted from the inclusion of human impact parameterizations. Results show that the between-model uncertainties in terms of SNRs in the VARSOC annual flow are larger (about 2 for global and varied magnitude for different basins) than those in the NOSOC, which are particularly significant in most areas of Asia and northern areas to the Mediterranean Sea. The SNR differences are mostly negative (-20 to 5, indicating higher uncertainty) for basin-averaged annual flow. The VARSOC high flow shows slightly lower uncertainties than NOSOC simulations, with SNR differences mostly ranging from -20 to 20. The uncertainty differences between the two experiments are significantly related to the fraction of irrigation areas of basins. The large additional uncertainties in VARSOC simulations introduced by the inclusion of parameterizations of human impacts raise the urgent need of GHMs development regarding a better understanding of human impacts. Differences in the parameterizations of irrigation, reservoir regulation and water withdrawals are discussed towards potential directions of improvements for future GHM development. We also discuss the advantages of statistical approaches to reduce the between-model uncertainties, and the importance of calibration of GHMs for not only better performances of historical simulations but also more robust and confidential future projections of hydrological changes under a changing environment.

Description: The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E greater than 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.

Description: We designed depth-graded multilayers, so-called supermirrors, with platinum/carbon (Pt/C) layer pairs for the Hard X-Ray Telescope (HXT) that was on-board the sixth Japanese X-Ray Astronomy Satellite Hitomi (ASTRO-H). The HXT has multinested thin foil optics, and the grazing angles of the x-ray mirrors are 0.07 to 0.27 deg. Supermirrors for HXTs are designed to provide a broad energy response (up to 80 keV) for astronomical requests. Under practical boundary conditions, we establish a block method applying empirical rules to maximize the integrated reflectivity. We fabricated Pt/C supermirrors using a DC magnetron sputtering system. The reflectivity of the mirrors was measured in a synchrotron radiation facility, SPring-8. We describe the design method for the supermirrors and our results.

Description: A decision framework is developed for quantifying the economic value of information (VOI) from the Gravity Recovery and Climate Experiment (GRACE) satellite mission for drought monitoring, with a focus on the potential contributions of groundwater storage and soil moisture measurements from the GRACE Data Assimilation (GRACE-DA) System. The study consists of: (a) the development of a conceptual framework to evaluate the socioeconomic value of GRACE-DA as a contributing source of information to drought monitoring; (b) structured listening sessions to understand the needs of stakeholders who are affected by drought monitoring; (c) econometric analysis based on the conceptual framework that characterizes the contribution of GRACE-DA to the US Drought Monitor (USDM) in capturing the effects of drought on the agricultural sector; and (d) a demonstration of how the improved characterization of drought conditions may influence decisions made in a real-world drought disaster assistance program. Results show that GRACE-DA has the potential to lower the uncertainty associated with our understanding of drought, and that this improved understanding has the potential to change policy decisions that lead to tangible societal benefits.

Description: The taxonomy of the ocean sunfishes (Molidae) has a complicated history. Currently, three genera and four species are recognized, including two in the genus Mola (M. mola and M. ramsayi). In 2009, a genetic study revealed a potential third species, Mola species C, in Southeast Australian waters. Concentrating on this region, we obtained samples and morphological data from 27 Mola sp. C specimens, genetically confirmed the existence of this species (mtDNA D-loop and cytochrome c oxidase 1), and established its morphology across a size spectrum of 50–242 cm total length. Mola sp. C is diagnosed by clavus meristics [15–17 fin rays (13–15 principal, 2 minor), 5–7 ossicles, paraxial ossicles separate], clavus morphology (prominent smooth band back-fold, rounded clavus edge with an indent), and body scale morphology (raised conical midpoints, non-branching). This species does not develop a protruding snout, or swollen dorso- or ventrolateral ridges. Body proportions remain similar with growth. A review of the historic literature revealed that Mola sp. C is a new, hitherto undescribed species, M. tecta, which we describe and diagnose, and that it is the first proposed addition to the genus Mola in 125 years. Its core distribution is likely in the temperate waters of the Southern Hemisphere.

Description: To evaluate the winter iron (Fe) supply processes fueling spring phytoplankton growth in the southern Sea of Okhotsk, the distributions of the Fe concentrations in seawater were investigated using hydrographic observations in late November (in the absence of sea ice) and mid-February (in the presence of sea ice). The results obtained from the hydrographic observations indicated a temporal increase in the Fe concentration in the surface mixed layer from November to February, which coincided with a decrease in seawater salinity. Changes in the alkalinity and oxygen isotopic composition of seawater indicated that the mixed layer in February was affected by sea ice meltwater as well as the less saline East Sakhalin Current (ESC) water, with a significant Fe supply originating from these waters. The magnitude of the Fe supply from these waters is greater than the upward Fe supply from deep water. The sea ice meltwater enriches the Fe in the near-surface water of the mixed layer, whereas the ESC water enriches the Fe at the depth of the mixed layer by the entrainment of sedimentary Fe associated with deep mixing due to Ekman transport. Additionally, the Fe nutritional status of the phytoplankton in the surface water of the ice-covered area was investigated by a shipboard incubation experiment. The results showed that bio-available Fe existed in the surface water and that large (〉10 μm) phytoplankton were not stressed by low Fe availability. The Fe supply processes related to sea ice melting and the ESC water inflow play important roles in sustaining the suitable Fe nutritional status of phytoplankton in the southern Sea of Okhotsk in early spring.

Description: Highlights • Compressional wave velocity measurements and cone penetration tests were applied to pressure cores. • Failure modes of pressure cores were assessed after cone penetration testing. • The cone factor for pressure cores was estimated to be 45. • Undrained shear strengths were estimated at 0.1–0.2 MPa under a 2400 m/s compressional wave velocity. Abstract Compressional wave velocity measurements and cone penetration tests were carried out for pressure cores recovered from the Krishna–Godavari Basin off the eastern coast of India, using an instrumented pressure testing chamber constructed by the Japanese National Institute of Advanced Industrial Science and Technology. For pressure cores with high gas hydrate saturations (Sh) and exhibited high compressional wave velocities also display a high loading force that resulted in tensile failure. A pressure core sample with low compressional wave velocities and low gas hydrate saturations led to a low loading force, which resulted in radial shear. The cone factor connecting the cone resistance and the undrained shear strength, Nk, was estimated using cone penetration testing and the uniaxial compressional results. We estimated its value as Nk = 45 by using a uniaxial compression loading speed of 0.01%/min and a cone insertion loading speed of 0.25 mm/s. Undrained shear strengths, estimated from cone penetration results using Nk = 45, were assumed to be equal to the tensile strengths between hydrate-hydrate and hydrate-particle interface when Sh is less than 50% and increases when Sh is more than 50% assuming that gas hydrate morphology was matrix supporting.