Atmospheric correction scheme for GLI with absorptive aerosol correction

The present study proposes an atmospheric correction scheme for Advanced Earth Observation Satellite II (ADEOS-II)/Global Imager (GLI) ocean color retrieval that corrects for the atmospheric absorptive aerosol effect. Radiative transfer simulations were conducted assuming a non-absorptive model aerosol with a soot-type aerosol at various mixture ratios. The results indicate that while the spectral dependency of aerosol reflectance does not change in the longer (>550 nm) wavelength region, the reflectance at shorter wavelengths is highly variable and depends on the mixture ratio. The influence of aerosol absorption was also investigated using GLI data from ocean areas adjacent to Japan in the presence of absorptive Siberian fire smoke aerosol in the spring of 2003. The spectral curvature of the aerosol was estimated from the data obtained. An empirical, iterative scheme that detects and evaluates the influence of absorptive aerosols was developed by comparing 380 nm GLI-observed aerosol reflectance with predicted reflectances derived using an in-water optical model. To evaluate the performance of this scheme, satellite-derived normalized water-leaving radiances were compared with those measured from a ferry servicing Nagasaki and Fukue. The results of data acquired on March 20, 2003, indicate that this absorption correction scheme improved root mean square estimation error for normalized water-leaving radiance by approximately 40% in the 380, 400, and 412 nm bands. This atmospheric correction algorithm was used as a part of the second version of the GLI standard ocean color data process system at Japan Aerospace Exploration Agency (JAXA).     

Degree of equilibration of eucritic pyroxenes and thermal metamorphism of the earliest planetary crust

Abstract— The pyroxenes in two new monomict eucrites from Antarctica, Yamato 791186 and Yamato 792510, have been studied and compared with those of other Antarctic and non-Antarctic eucrites. The purpose of this study is to identify compositional and textural relationships shown by these pyroxenes which may be used as indicators of the thermal history of the meteorite. An attempt is made, using petrographic and compositional criteria, to distinguish between the initial cooling history and subsequent thermal events. We suggest that it is possible to identify stages of thermal “metamorphism” which may be used to indicate the conditions on the surface and crust of the parent body. A picture of the geological setting of the HED (Howardites, Eucrites, Diogenites) parent body is proposed, for which thermal metamorphism by impact heating is an important process.     

Dissolved Organic Matter in Oceanic Waters

The amount of information on oceanic dissolved organic matter (DOM) has increased dramatically in the last decade thanks to the advances in chemical characterization. This information has supported the development of some novel and important ideas for DOM dynamics in the ocean. Consequently, we have a better understanding of the importance of DOM in oceanic biogeochemical cycles. Here we review studies published mainly during 1995–2001, synthesize them and discuss unsolved problems and future challenges. The measurement, distribution and turnover of dissolved organic carbon (DOC) are presented as the bulk dynamics of the oceanic DOM. The size spectrum, elemental composition, and chemical compositions at molecular and functional group levels are described. The mechanisms proposed for the survival of biomolecules in DOM are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Planetary growth with collisional fragmentation and gas drag

As planetary embryos grow, gravitational stirring of planetesimals by embryos strongly enhances random velocities of planetesimals and makes collisions between planetesimals destructive. The resulting fragments are ground down by successive collisions. Eventually the smallest fragments are removed by the inward drift due to gas drag. Therefore, the collisional disruption depletes the planetesimal disk and inhibits embryo growth. We provide analytical formulae for the final masses of planetary embryos, taking into account planetesimal depletion due to collisional disruption. Furthermore, we perform the statistical simulations for embryo growth (which excellently reproduce results of direct N-body simulations if disruption is neglected). These analytical formulae are consistent with the outcome of our statistical simulations. Our results indicate that the final embryo mass at several AU in the minimum-mass solar nebula can reach about ∼0.1 Earth mass within 10⁷ years. This brings another difficulty in formation of gas giant planets, which requires cores with ∼10 Earth masses for gas accretion. However, if the nebular disk is 10 times more massive than the minimum-mass solar nebula and the initial planetesimal size is larger than 100 km, as suggested by some models of planetesimal formation, the final embryo mass reaches about 10 Earth masses at 3-4 AU. The enhancement of embryos’ collisional cross sections by their atmosphere could further increase their final mass to form gas giant planets at 5-10 AU in the Solar System.     

Nonlinearity of the horizontal velocity field under wind-waves

Using the data from a wind-tunnel experiment, bispectra of orbital-motions of wind-waves and of turbulence are calculated, and nonlinear interaction of wind-waves with turbulence in water are discussed. The wind-waves or the orbital motions of them, at first, produce the turbulence coherent with themselves, and then this coherent turbulence changes to the turbulence noncoherent with wind-waves. Nonlinearity of the velocity fluctuations in the surface layer in water under wind-waves is almost due to the nonlinear energy transfer from the orbital motions of wind-waves to the coherent turbulence. The vertical variations of the power spectra and of the normalized bispectra suggest that the wind driven currents near the surface play an important role in the process from orbital motion of wind-waves to noncoherent turbulence.     

Relationship between petroleum hydrocarbon and plankton in a mesocosm experiment

~IOXWith economic development and consumer demand, oil pollutants have been one of themain marine pollutants in the coastal regal Of China. The oil-contaminated area incrsharply to 69% in 1995 and its average criterion index reached up to 2. 17 in the ChangjiangEstuary (NBEP, 1996). TO assess the influences Of the oil POllutants on the marine ~tern, it is neceSSary to develOP a mathematical kinetic model of the tranSport, distribution andfate in the marine ~teln, espeCially to esthate …     

Loss Processes of Sinking Fecal Pellets of Zooplankton in the Mesopelagic Layers of the Antarctic Marginal Ice Zone

A time-series sediment trap deployment was carried out in the marginal ice zone (MIZ) of the Antarctic Ocean (64°42′ S, 139°58′E; sea depth of 2930 m), during the austral summer. Cylindrical fecal pellets were the predominant sinking particles at 537 m in the middle of January and most of them disappeared below that depth, the loss of which were 25.3 mg C m⁻² day⁻¹ in the depth range of 537–796 m. Small-sized sinking particles other than fecal pellets increased in that depth range. Analyses of fecal pellets for remnant DNA corresponding to 16S mitochondrial RNA and 28S ribosomal RNA suggested that the large cylindrical fecal pellets at 537 m were produced by Antarctic krill (Euphausia superba) and copepods. According to the presence of the DNA associated with sinking particles, E. superba fecal pellets rapidly disappeared below 537 m, while copepod fecal pellets still remained in the mesopelagic and bathypelagic layers. Small-sized amorphous sinking particles at 537 m also contained E. superba- and copepod-derived DNA. The abundance of trap-collected copepods (Oithona spp. and Oncaea spp.) which are known to be coprophagous increased at 796 m where many fecal pellets disappeared. We suggest that those rapidly sinking pellets were fragmented by copepods with intensified coprorhexy activity (fragmentation of fecal pellets) in the mesopelagic layers, reducing their sinking rates. These smaller and slower sinking particles can be important food sources for detritivorus or coprophagous animals in mesopelagic and bathypelagic layers in the MIZ. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparison of downward surface solar radiation derived from GMS5/VISSR and of reanalysis products

A high-resolution downward surface solar radiation (DSSR) dataset has been produced using geostationary meteorological satellite measurements. Its validation with in situ observations shows that the daily satellite DSSRs are highly accurate. Comparing the satellite DSSRs with reanalysis DSSR datasets, the former has higher probability density in a low value range, and lower density in a high value range. Overestimations of the reanalysis DSSR are significant in the low range. Correlations between the reanalysis DSSRs and the satellite DSSR are relatively low in the tropics. It is suggested that the satellite DSSRs have good potential to capture cloud behavior in the tropics.     

Occurrence of Two Distinct Types of Tissue Inhibitors of Metallo-proteinases-2 in Fugu rubripes

In this study, genes of two distinct tissue inhibitors of metalloproteinases-2 （TIMP-2） from Japanese puffer fish Fugu rubripes, Fugu TIMP-2a and TIMP-2b, were cloned. The open reading frames of Fugu TIMP-2a and TIMP-2b cDNAs are composed of 660 and 657 nucleotides and 220 and 219 amino acids, respectively. Both Fugu TIMP-2s contain 12 cysteine residues, which might form six disulfide bonds as in other animals＇ TIMP-2s. Reverse-transcribed polymerase chain reaction analysis showed the mRNAs of Fugu TIMP-2a and TIMP-2b to be expressed in some tissues examined with different expression patterns. These findings suggest that the two distinct Fugu TIMP-2s might perform different functions in Fugu tissues.