Infrared polarization of venus: Its periodic fluctuations and evidence for thin haze

Infrared polarimetry of Venus over the phase angles from 18 to 171° has been made extending previous measurements (S. Sato, K. Kawara, Y. Kobayashi, H. Okuda, K. Noguchi, T. Mukai, and S. Mukai (1980). Icarus43, 288) in both wavelength λ and phase angle θ. The results of polarization measurements at 2.25 μm ? λ ? 5.0 μm are (i) small positive and negative values at K(2.25 μm), (ii) a remarkable variation with λ in the CVF(2.2?4.2μm) filter region, (iii) a nearly smooth curve as a function of θ having a peak value of ～36% at θ ～ 90° at both 3.6 μm and L′(3.8 μm), and (iv) a decrease with increasing field of view at M(5.0 μm) due to the contamination of thermal emission from the dark crescent. Furthermore, at 3.6 μm and L′(3.8 μm), (v) higher values at the poles than at the equator and (vi) 4.5- to 5.9-day periodic fluctuations are also found. From a comparison with model calculations, the results confirm the existence of a thin haze layer consisting of submicron-size particles above the main clouds of Venus; e.g., its optical thickness is about 0.1 at λ ～ 0.94 μm. In addition, result (vi) could be explained by a variation of the optical thickness of the haze layer or that of the brightness temperature of the main clouds.     

Ecologic and taxonomic diversification in the Mesozoic brackish-water bivalve faunas in Japan, with emphasis on infaunalization of heterodonts

Mesozoic brackish-water bivalve faunas in Japan diversified in three steps: at the beginning of the Early Jurassic, Early and Late Cretaceous. The Hettangian Niranohama Fauna in northeastern Honshu represents the establishment of a heterodont-dominated brackish-water fauna that persisted until the early Late Cretaceous. No similar composition is known from the Triassic. The infauna consists mostly of non-siphonate and some short-siphonate heterodonts, while the epifauna is represented by diverse pteriomorphian families. In the Early Cretaceous Tetori Group in central Honshu, the long-siphonate heterodonts Tetoria (Corbiculidae) and the semi-infaunal soft-bottom oyster Crassostrea appeared. The evolutionary diversification of the latter, known as the most important element of modern brackish-water faunas, may thus originate at that time. In the early Late Cretaceous (Cenomanian) of the Goshoura and Mifune Groups in west Kyushu, several euryhaline deep-burrowing heterodont families, such as Veneridae and Tellinidae, further diversified in the brackish and marine environments. The Late Cretaceous is characterized by massive shell biolithic beds in which large Crassostrea species are common, a feature common for Cenozoic brackish-water faunas. The long-term changes in the composition of the brackish-water faunas in Japan represents thus an evolutionary record, irrespective of the severe physiological and environmental conditions imposed on the highly conservative nature of the fauna.     

A Simple Single-Layer Urban Canopy Model For Atmospheric Models: Comparison With Multi-Layer And Slab Models

We developed a simple, single-layer urban canopy model, and comparedit to both multi-layer and slab models. Our single-layer model has thefollowing features: (a) It is a column model of energy and momentumexchange between an urban surface and the atmosphere, (b) it includesthe influence of street canyons, which are parameterized to representthe urban geometry, (c) it includes shadowing from buildings andreflection of radiation, and (d) it estimates both the surfacetemperatures of, and heat fluxes from, three surface types: roof, wall,and road. In the simulation of the single-layer model, the roof washottest during the daytime, but coolest from midnight to early morning.This is consistent with output from the multi-layer model and fieldobservations at a residential area on a clear, summer day. The diurnalvariation of the energy budget from the single-layer model agrees wellwith that from the multi-layer model. Our single-layer model'sperformance is nearly that of a multi-layer model for studyingmesoscale heat islands. Nevertheless, it is simply parameterized,and thus easily included in larger-scale atmospheric models. The slabmodel has the largest nighttime cooling rate of the three models. Toovercome this, it needs more adjustments than for the canopy models.     

Preliminary observation of missing energy flux of sunspot

We have searched for the missing energy flux of the sunspot by measuring white-light photographs over the region around the sunspots exceeding ten times of the diameter of spots. It was found that the excess brightness amounts to 0.3–0.8% of the local continuum intensity immediately beyond the penumbra and smoothly decrease to zero at the edge of our inspected radii of 130 000–160000km. This result suggests that the flux deficit in sunspots of the order of 30% over the umbra-penumbra is roughly the same as the excess flux found in the very large surrounding region which includes photospheric facular contributions. Among nineteen spots fourteen showed this extended bright ring. Narrow band photoelectric scans revealed that the excess radiation originates in the continuum, not from weakened absorption lines.     

Nitrous oxide in the sea

A new gas chromatographic method was developed for the measurement of nitrous oxide (N₂O) in seawater. It takes 15 min for the analysis in a sample of 640 ml seawater.By this method, more than 1000 samples taken over various depths and areas in the sea were analyzed. In the western North Atlantic, the N₂O concentration over a range of oceanic depths gave characteristic profiles that were negatively correlated with oxygen profiles, reaching its maximum (c.a. 1 μg/l) in the oxygen-minimum layer at mid-depths. In the Caribbean, the N₂O maximum reached higher concentrations than in the North Atlantic. N₂O was near equilibrium with that in the atmosphere in Atlantic surface waters, but supersaturation of N₂O was observed in surface waters of the Gulf of St. Lawrence in early June and in most surface samples from the Caribbean Sea in March.The estimated rate of N₂O production in the sea may be significant in terms of geochemical cycling of combined nitrogen to the atmosphere.     

Resonance sticking in the scattered disk

We investigate the dynamical evolution of trans-neptunian objects (TNOs) in typical scattered disk orbits (scattered TNOs) by performing simulations using several thousand particles lying initially on Neptune-encountering orbits. We explore the role of resonance sticking in the scattered disk, a phenomenon characterized by multiple temporary resonance captures (‘resonances’ refers to external mean motion resonances with Neptune, which can be described in the form r:s, where the arguments r and s are integers). First, all scattered TNOs evolve through intermittent temporary resonance capture events and gravitational scattering by Neptune. Each scattered TNO experiences tens to hundreds of resonance captures over a period of 4 Gyr, which represents about 38% of the object's lifetime (mean value). Second, resonance sticking plays an important role at semimajor axes , where the great majority of such captures occurred. It is noteworthy that the stickiest (i.e., dominant) resonances in the scattered disk are located within this distance range and are those possessing the lowest argument s. This was evinced by r:1, r:2 and r:3 resonances, which played the greatest role during resonance sticking evolution, often leading to captures in several of their neighboring resonances. Finally, the timescales and likelihood of temporary resonance captures are roughly proportional to resonance strength. The dominance of low s resonances is also related to the latter. In sum, resonance sticking has an important impact on the evolution of scattered TNOs, contributing significantly to the longevity of these objects.     

Density,biomass and community structure of demersal fishes off the Pacific coast of northeastern Japan

Demersal fish communities were studied on the lower continental shelf and the upper continental slope along the Pacific coast of northeastern Japan. Species composition, number and weight of each species were examined based on otter trawl samples at 45 stations. Mean density and biomass of demersal fishes were 131 ha^–1 and 21 kg ha^–1, respectively. The ten most abundant species comprised of about 95% of total number and weight of overall catch indicating simple species composition. Gadiform fishesTheragra chalcogramma, Gadus macrocephalus andPhysiculus maximowiczi were the most important species by number, weight and frequency of occurrences, and three main community types represented by the three key species were recognized.Theragra-dominant community showed higher density and biomass, and lower diversity thanPhysiculus-dominant community did. Species diversity of demersal fish community was negatively correlated to density and biomass. Density and biomass of demersal fish community were high on the uppermost slope, and the high abundance resulted from low-diversity communities dominated byT. chalcogramma andG. macrocephalus.     

OSL dating of glacial deposits during the Last Glacial in the Terskey-Alatoo Range, Kyrgyz Republic

Optically stimulated luminescence (OSL) dating was applied to glacial and loess deposits in the north flank of the Terskey-Alatoo Range, Kyrgyz Republic, to elucidate the glacier chronology of the central Asian mountains during the Last Glacial. Moraines in five parts of study area were classified into four stages (Terskey Stages I–IV) based on their geographical position and elevation, and their moraine rock weathering. According to this classification, the oldest moraines (Terskey Stage I) were at 2100–2250 m a.s.l. and the second-oldest moraines (Terskey Stage II) were at 2400–2700 m a.s.l. Quartz samples from moraines of these two stages were used for OSL dating. The OSL ages of the quartz samples indicate that glacier expansion in the Terskey Stage II occurred between 21 and 29 ka BP.     

Measures for groundwater security during and after the Hanshin-Awaji earthquake (1995) and the Great East Japan earthquake (2011), Japan

Many big earthquakes have occurred in the tectonic regions of the world, especially in Japan. Earthquakes often cause damage to crucial life services such as water, gas and electricity supply systems and even the sewage system in urban and rural areas. The most severe problem for people affected by earthquakes is access to water for their drinking/cooking and toilet flushing. Securing safe water for daily life in an earthquake emergency requires the establishment of countermeasures, especially in a mega city like Tokyo. This paper described some examples of groundwater use in earthquake emergencies, with reference to reports, books and newspapers published in Japan. The consensus is that groundwater, as a source of water, plays a major role in earthquake emergencies, especially where the accessibility of wells coincides with the emergency need. It is also important to introduce a registration system for citizen-owned and company wells that can form the basis of a cooperative during a disaster; such a registration system was implemented by many Japanese local governments after the Hanshin-Awaji Earthquake in 1995 and the Great East Japan Earthquake in 2011, and is one of the most effective countermeasures for groundwater use in an earthquake emergency. Emphasis is also placed the importance of establishing of a continuous monitoring system of groundwater conditions for both quantity and quality during non-emergency periods.