We present digitized photographs of the white-light solar corona taken during the total solar eclipse of 22–23 November, 1984, on both calibrated black-and-white film and on color film. Conditions on site in Hula, Papua New Guinea, were exceptionally clear. The color image was used to produce an isophotal map of the inner corona, from which a flattening coefficient of 0.23 was measured. The black-and-white image was enhanced through a digital radial filter. Our images are the best processed images available from the 1984 eclipse and so provide important data for synoptic observations. 相似文献
Reconciliation of paleolimnology inference models with hindcasts from mechanistic water column models aided the reconstruction of past relationships for total phosphorus/dissolved oxygen and acid neutralizing capacity/pH in highly polluted lake ecosystems in New York State. Pre-disturbance Onondaga Lake, Syracuse, NY, was shown to have experienced seasonal hypolimnetic anoxia even under oligotrophic (<10 ug l?1) phosphorus levels. In the Adirondack Mountains of New York State the paired modeling confirmed that, while many lakes have the potential to eventually recover from acidification by atmospheric deposition, approximately 30% likely experienced naturally acidic conditions (pH < 6) prior to increases in industrial emissions. Comparison between the model results illuminated areas of individual model inadequacy, improved understanding of lake ecology, and increased confidence in the ability of predictive water column models to accurately develop restoration scenarios representing improved conditions. The work presented here is the first such comparison modeling for total phosphorus, dissolved oxygen, and acid neutralizing capacity. The technique remains to be more widely applied geographically and extended to less heavily stressed lake systems. Because a fossil inference and mechanistic hindcast should independently lead to similar results, comparison modeling is a potentially powerful tool for examining past interactions between ecosystem structure and ecosystem functioning. 相似文献
Approximately 1300 measurements of the positions of 101 features in Jupiter's atmosphere have been made using blue-light photographs of the planet obtained by the International Planetary Patrol from 1970 to 1972. The longitudinal positions of features were read directly with orthographic grids superimposed on optically projected images of Jupiter. For each feature, least-squares linear fits were made on plots of the longitude measurements as a function of time, in order to derive drifts rates relative to System I or II. Drift rates were used to compute rotation periods; and, by combining the data from various latitudes, short-term rotation profiles were constructed. These short-term profiles are compared with a “mean” multiple-year profile, and differences in detail are evident. Slightly shorter rotation periods were found near the edges of the equatorial jet than at its center in 1970 and 1971. In 1972, one feature at +37° north was found to exhibit an abrupt change in period amounting to an increase of 95.1 seconds. 相似文献
A reverse phase High Performance Liquid Chromatography (HPLC) method was developed to detect soluble reactive phosphate (SRP) in marine and freshwater samples. This technique is scalable over a range of sample volumes from 10 μl to 10 ml, requires minimal sample preparation, and responds linearly from 1 nM to 100 μM (R2>0.964). Standard Murphy–Riley molybdenum blue reagents were used to react with phosphate in samples for analysis. Solid phase extraction tubes were used to clean the mixed complexing reagent prior to combining the reagent with samples. The method was applied to freshwater samples collected in July 2001 along an Andean mountain stream located in the Eastern Cordillera (2400 m) of Peru and marine samples collected in January 2002 within the low marsh of the estuarine Nueces Delta System, Texas Coastal Bend. For method comparison, field samples were analyzed using a standard manual spectrophotometric method. Field sample phosphate concentrations produced from each method were nearly identical. This method offers the advantages of low sample volume (1 ml or less) with high sensitivity, precision, and potential automation. 相似文献
Total suspended matter in the water column of the Caribbean was determined quantitatively by means of filtration through 0.45 μ membrane filters. Results show that prior values obtained by centrifuging methods are too low, and that the existence of a nepheloid layer cannot be gravimetrically demonstrated in the Caribbean. 相似文献
Disaster preparedness plans reduce future damages, but may lack testing to assess their effectiveness in operation. This study used the state-designed Local Government Unit Disaster Preparedness Journal: Checklist of Minimum Actions for Mayors in assessing the readiness to natural hazards of 92 profiled municipalities in central Philippines inhabited by 2.4 million people. Anchored on the Hyogo Framework for Action 2005–2015, it assessed their preparedness in 4 criteria—systems and structures, policies and plans, building competencies, and equipment and supplies. Data were analyzed using statistical package for social sciences, frequency count, percentage, and weighted mean. The local governments were found highly vulnerable to tropical cyclone and flood while vulnerable to earthquake, drought, and landslide. They were partially prepared regardless of profile, but the coastal, middle-earning, most populated, having the least number of villages, and middle-sized had higher levels of preparedness. Those highly vulnerable to earthquake and forest fire were prepared, yet only partially prepared to flood, storm surge, drought, tropical cyclone, tornado, tsunami and landslide. The diverse attitude of stakeholders, insufficient manpower, and poor database management were the major problems encountered in executing countermeasures. Appointing full-time disaster managers, developing a disaster information management system, massive information drive, organizing village-based volunteers, integrating disaster management into formal education, and mandatory trainings for officials, preparing for a possible major volcanic eruption and crafting a comprehensive plan against emerging emergencies like the COVID-19 pandemic may lead to a 360° preparedness.
We report a study on the broadband ultraviolet photolysis of methane-water ice mixtures, at low methane concentrations and temperatures relevant to the icy satellites of the outer Solar System. The photochemistry of these mixtures is dominated by the action of hydroxyl radicals on methane and the resulting products. This implies that, given sufficient exposure time, the methane will eventually be completely oxidized to carbon dioxide. The presence of methane inhibits the formation of hydrogen peroxide by serving as a trap for hydroxyl radicals. The distribution of photochemical products is broadly similar to that previously conducted using ion and electron sources, with some differences possibly attributable to the difference in radiation source. The results are applicable to a variety of icy bodies in the Solar System. On Enceladus, where methane mixed with water is measured in the plumes, methane in the surface ices is subject to oxidation and will eventually be converted to CO2. The CH stretch feature detected in the VIMS spectra of the Enceladus surface ice suggests that methane is currently being supplied to the surface ice, likely from re-condensation of the plume gas. 相似文献
We amassed statistics for quiet-sun chromosphere spicules at the limb using ground-based observations from the Swedish 1-m Solar Telescope on La Palma and simultaneously from NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft. The observations were obtained in July 2006. With the 0.2 arcsecond resolution obtained after maximizing
the ground-based resolution with the Multi-Object Multi-Frame Blind Deconvolution (MOMFBD) program, we obtained specific statistics
for sizes and motions of over two dozen individual spicules, based on movies compiled at 50-second cadence for the series
of five wavelengths observed in a very narrow band at Hα, on-band and at ± 0.035 nm and ± 0.070 nm (10 s at each wavelength)
using the SOUP filter, and had simultaneous observations in the 160 nm EUV continuum from TRACE. The MOMFBD restoration also
automatically aligned the images, facilitating the making of Dopplergrams at each off-band pair. We studied 40 Hα spicules,
and 14 EUV spicules that overlapped Hα spicules; we found that their dynamical and morphological properties fit into the framework
of several previous studies. From a preliminary comparison with spicule theories, our observations are consistent with a reconnection
mechanism for spicule generation, and with UV spicules being a sheath region surrounding the Hα spicules. 相似文献