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The 1998 eruption of Volcan Cerro Azul, Isla Isabela, Galápagos Islands, was observed in near real-time by the Geostationary
Operational Environmental Satellite-8 (GOES-8) weather satellite. Due to the remote location of the eruption site, 3.9-μm
radiance values derived from GOES band 2 provide the best timing of the start and termination of the eruption, which occurred
on 15 Sept. and 21 Oct., respectively. Throughout the 36-day long eruption, a total of 1335 thermal infrared images were collected,
of which 851 were cloud-free and permitted the thermal anomaly to be detected. A detailed chronology including 77 separate
events was assembled from the GOES data and field observations. Numerous attributes of the eruption were observed from the
GOES data, including the sizes and dispersal of seven eruption plumes and the occurrence and timing of intra-caldera effusive
activity. The growth of a lava flow on the SE flank, the formation of smoke and volcanic haze from the flank vent, and burning
of vegetation caused by lava flows entering vegetated areas were monitored both on the ground and with the satellite data.
In most cases GOES images were processed as they were received every 30 min and were then distributed over the Internet within
minutes of reception. These data provided timely high-temporal information to field parties as well as enabled the documentation
of the eruption. The GOES observations of Cerro Azul serve as a further example of the way in which the remote sensing community
and field volcanologists can collaborate during future eruptions, and permit the temporal and spatial resolution requirements
for future satellites systems to be better defined.
Received: 27 April 1999 / Accepted: 21 February 2000 相似文献
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We have mapped the J = 1 --> 0 transition of 13CO over a 3 deg2 region in Heiles Cloud 2 using the Five College Radio Astronomy Observatory 14 m telescope. The complete map contains 3600 individual spectra of which 2400 were sampled with 1' spacing. The map suggest that the structure of Heiles Cloud 2 is dominated by a quasi equilibrium rotating ring similar to those found in numerical calculations of the gravitational collapse of a rotating cloud. Within this ring, several dense condensations have been identified and partially mapped in C18O. These subcondensations, among which is the dense filament TMC-1, probably result from the instability of the ring to fragmentation and have masses on the order of the Jeans mass. Thus, they are marginally unstable to further collapse and may be the precursors of fragments that will eventually form stars. 相似文献
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P. Szefer G. P. Glasby J. Geldon R. M. Renner E. Björn J. Snell W. Frech J. Warzocha 《Environmental Geology》2009,57(4):847-862
Analysis of 59 surface sediment samples from the Polish exclusive economic zone (EEZ) shows that Szczecin Lagoon sediments
are the most polluted by heavy metals and that the degree of heavy-metal pollution decreases substantially on passing from
the Szczecin Lagoon to the Pomeranian Bay and the inner shelf area and then on passing to the Bornholm Deep and Słupsk Furrow.
Heavy-metal pollution in the sediments of the western part of the Polish EEZ therefore appears to follow the dispersion of
the Oder River. Fluffy material from the Oder estuary appears to be the main source of heavy metals in the muddy sediments
of the Bornholm Deep. The formation of sulphides is therefore not the principal factor controlling the enrichment of heavy
metals in the sediments of this anoxic basin, although it may be responsible for the uptake of Mo, Sb and As. Two main factors
control the distribution of the rare earth elements (REE) in sediments of the Polish EEZ: the input of Fe-organic colloids
from rivers and the presence of detrital material in the sediments. 相似文献