Long-range transport of particulate polycyclic aromatic hydrocarbons at Cape Hedo remote island site in the East China Sea between 2005 and 2008

Particle-associated polycyclic aromatic hydrocarbons (PAHs) in outflow from East Asia were observed at Cape Hedo, Okinawa, Japan between 2005 and 2008. The filter samples of the total suspended particles were analyzed by means of gas chromatography-mass spectrometry. The total concentration of fourteen 3–7-ring PAHs was 0.01–24 ng m^?3 (average 1.6 ng m^?3). The average PAH concentration increased in the winter-spring season and decreased in the summer-fall season. The average benzo(a)pyrene to benzo(e)pyrene ratio was 0.49 in the winter-spring season and was lower than the literature values for East Asian cities in the same season. This result shows that aging of organic aerosol particles proceeds during long-range transport from East Asia. In the Asian Pacific region, these pollutants are transported from East Asia in the winter-spring season, whereas clean air mass is transported from the Pacific Ocean in the summer-fall season.     

A carbon‐isotopic study of an end‐Permian mass‐extinction horizon,Bulla, northern Italy: a negative δ13C shift prior to the marine extinction

Palaeontological data from the Permian‐Triassic Bulla section, northern Italy, demonstrate a rapid extinction at this site. This occurs after a negative carbonate carbon‐isotope (δ¹³C_carb) shift, consistent with two other northern Italian sites (Val Badia and Tesero). However, conclusion goes against recent reporting that the extinction occurs before the δ¹³C_carb shift. We agree that the shift occurs after the extinction at Jameson Land, east Greenland (a high latitude palaeolocation). However, all other sections show the shift before, or coincident with, the extinction. We suggest that the simplest explanation is a coeval shift in carbonate carbon‐isotope shifts, and it follows that the extinction was not. This suggests that the end‐Permian extinction crept from region to region. It also suggests that the marine extinction occurred first in high northern latitudes.     

Oceanic crust production and climate during the last 100 Myr

In order to evaluate the possible influence of oceanic crust production on climatic changes during the past 100Myr variations in total oceanic crust for this period including production at mid-ocean ridges, oceanic plateaus, and back-arc basins were calculated using the most recent and accurate time-scales. The rates presented here differ from those of Larson (1991a, b) on Cenozoic fluctuations and show that (1) maximum production values occurred during the Cenomanian, Palaeocene, and late Oligocene-early Miocene and (2) minimum values occurred in Campanian-Maastrichtian, late Eocene, and middle Miocene. Significantly, variations of oceanic crust production correspond with variations in the δ¹⁸O of deep-water benthic foraminifera: maximum values of oceanic crust production correspond with minimum values of δ¹⁸O, and minimum production values with maximum values of δ¹⁸O. This latter synchronism suggests that changes in land-sea relationships and atmospheric CO₂ related to major fluctuations in oceanic crust production were the main cause of mid-Cretaceous warming and Late Cretaceous cooling, and of climatic quasi-cycles having a periodicity of 33–38 million years over the last 100 Myr. This is the first report showing variations of ocean crust production synchronized with the Cenozoic climate changes.     

Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science

To comprehensively understand the Arctic and Antarctic upper atmosphere, it is often crucial to analyze various data that are obtained from many regions. Infrastructure that promotes such interdisciplinary studies on the upper atmosphere has been developed by a Japanese inter-university project called the Inter-university Upper atmosphere Global Observation Network （1UGONET）. The objective of this paper is to describe the infrastructure and tools developed by IUGONET. We focus on the data analysis software. It is written in Interactive Data Language （IDL） and is a plug-in for the THEMIS Data Analysis Software suite （TDAS）, which is a set of IDL libraries used to visualize and analyze satellite- and ground-based data. We present plots of upper atmospheric data provided by IUGONET as examples of applications, and verify the usefulness of the software in the study of polar science. We discuss IUGONET＇s new and unique developments, i.e., an executable file of TDAS that can run on the IDL Virtual Machine, IDL routines to retrieve metadata from the IUGONET database, and an archive of 3-D simulation data that uses the Common Data Format so that it can easily be used with TDAS.     

Real-time geophysical measurements on the deep seafloor usingsubmarine cable in the southern Kurile subduction zone

A permanent real-time geophysical observatory using a submarine cable was developed and deployed to monitor seismicity, tsunamis, and other geophysical phenomena in the southern Kurile subduction zone. The geophysical observatory comprises six bottom sensor units, two branching units, a main electro-optical cable with a length of 240 km and two land stations. The bottom sensor units are: 1) three ocean bottom broadband seismometers with hydrophone; 2) two pressure gauges (PGs); 3) a cable end station with environmental measurement sensors. Real-time data from all the undersea sensors are transmitted through the main electro-optical cable to the land station. The geophysical observatory was installed on the continental slope of the southern Kurile trench, southeast Hokkaido, Japan in July 1999. Examples of observed data are presented. Sensor noises and resolution are mentioned for the ocean bottom broadband seismometers and the PGs, respectively. An adaptable observation system including very broadband seismometers is scheduled to be connected to the branching unit in late 2001. The real-time geophysical observatory is expected to greatly advance the understanding of geophysical phenomena in the southern Kurile subduction zone