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311.
Glenn J. Veeder Dennis L. Matson Torrence V. Johnson Ashley G. Davies Diana L. Blaney 《Icarus》2004,169(1):264-270
Polar brightness temperatures on Io are higher than expected for any passive surface heated by absorbed sunlight. This discrepancy implies large scale volcanic activity from which we derive a new component of Io's heat flow. We present a ‘Three Component’ thermal background, infrared emission model for Io that includes active polar regions. The widespread polar activity contributes an additional ∼0.6 W m−2 to Io's heat flow budget above the ∼2.5 W m−2 from thermal anomalies. Our estimate for Io's global average heat flow increases to ∼3±1 W m−2 and ∼1.3±0.4×1014 watts total. 相似文献
312.
Susan H. Cannon Eric M. Boldt Jayme L. Laber Jason W. Kean Dennis M. Staley 《Natural Hazards》2011,59(1):209-236
Following wildfires, emergency-response and public-safety agencies can be faced with evacuation and resource-deployment decisions
well in advance of coming winter storms and during storms themselves. Information critical to these decisions is provided
for recently burned areas in the San Gabriel Mountains of southern California. A compilation of information on the hydrologic
response to winter storms from recently burned areas in southern California steeplands is used to develop a system for classifying
magnitudes of hydrologic response. The four-class system describes combinations of reported volumes of individual debris flows,
consequences of debris flows and floods in an urban setting, and spatial extents of the hydrologic response. The range of
rainfall conditions associated with different magnitude classes is defined by integrating local rainfall data with the response
magnitude information. Magnitude I events can be expected when within-storm rainfall accumulations (A) of given durations (D) fall above the threshold A = 0.4D
0.5 and below A = 0.5D
0.6 for durations greater than 1 h. Magnitude II events will be generated in response to rainfall accumulations and durations
between A = 0.4D
0.5 and A = 0.9D
0.5 for durations less than 1 h, and between A = 0.5D
0.6 and A = 0.9D
0.5 or durations greater than 1 h. Magnitude III events can be expected in response to rainfall conditions above the threshold
A = 0.9D
0.5. Rainfall threshold-magnitude relations are linked with potential emergency-response actions as an emergency-response decision
chart, which leads a user through steps to determine potential event magnitudes and identify possible evacuation and resource-deployment
levels. Use of this information in planning and response decision-making process could result in increased safety for both
the public and emergency responders. 相似文献
313.
314.
Aimée J. D. Pelletier Dennis E. Jelinski Malte Treplin Martin Zimmer 《Estuaries and Coasts》2011,34(4):863-871
Sandy beaches are characterised by heterogeneously distributed food sources both in time and space. The major energy supply
is derived from marine subsidies in the form of beach-cast macrophyte wrack. Wrack patches are short-lived, and their position
on the beaches varies with tidal and seasonal cycles as well as weather conditions. Little is known about how sandy beach
inhabitants orient themselves towards, and colonise, wrack patches. In a series of field studies on islands off Vancouver
Island (British Columbia, Canada), colonisation patterns of wrack patches by beach fleas and sand hoppers (Amphipoda: Talitridae),
the most abundant macrofaunal detritivores, were studied. As indicated by colonisation of experimental patches of wrack and
wrack surrogates that were either visible or buried in the sand, beach fleas (Traskorchestia traskiana) rely on olfactory cues for locating freshly deposited wrack patches in their patchy and dynamic habitat. Dense colonisation
of freshly deposited algal wrack generally occurred within less than 1 h but depended upon the tidal height of wrack patches.
Beach flea density in freshly deposited wrack patches increased with increasing tidal height. By contrast, sand hoppers (Megalorchestia californiana) colonised freshly deposited wrack patches in densities that decreased with tidal height. Discussing these interspecific
differences, we provide a primer for future detailed studies on transport of matter along the marine–terrestrial gradient
of sand beaches. 相似文献
315.
Gabriella De Lucia Bianca M. Poggianti Alfonso Aragón-Salamanca Simon D. M. White Dennis Zaritsky Douglas Clowe Claire Halliday Pascale Jablonka Anja von der Linden Bo Milvang-Jensen Roser Pelló Gregory Rudnick Roberto P. Saglia Luc Simard 《Monthly notices of the Royal Astronomical Society》2007,374(3):809-822
316.
Lan Cuo Dennis P. Lettenmaier Bernt V. Mattheussen Pascal Storck Matthew Wiley 《水文研究》2008,22(21):4205-4213
Some relatively straightforward modifications to the Distributed Hydrology–Soil–Vegetation Model (DHSVM) are described that allow it to represent urban hydrological processes. In the modified model, precipitation that falls on impervious surfaces becomes surface runoff, and a spatially varying (depending on land cover) fraction of surface runoff is connected directly to the stream channel, with the remainder stored and slowly released to represent the effects of stormwater detention. The model was evaluated through application to Springbrook Creek watershed in a partially urbanized area of King County, Washington. With calibration, the modified DHSVM simulates hourly streamflow from these urbanized catchments quite well. It is also shown how the revised model can be used to study the effects of continuing urbanization in the much larger Puget Sound basin. Model simulations confirm many previous studies in showing that urbanization increases peak flows and their frequency, and decreases peak flow lag times. The results show that the urbanization parameterizations for DHSVM facilitate use of the model for prediction and/or reconstruction of a range of historic and future changes in land cover that will accompany urbanization as well as other forms of vegetation change. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
317.
Gallagher Peter T. Dennis Brian R. Krucker Säm Schwartz Richard A. Tolbert A. Kimberley 《Solar physics》2002,210(1-2):341-356
Solar Physics - Observations of the X1.5 flare on 21 April 2002 are reviewed using the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) and the Transition Region and Coronal Explorer... 相似文献
318.
During the autumn of 2000, large areas of England and Wales were affected by severe flooding, which caused widespread disruption and significant damage to property. This study attempts to determine the impact of these flood events on contaminated sediment dispersal and deposition in the River Swale catchment, Yorkshire, UK, where lead and zinc were extracted and processed in large quantities during the nineteenth century. Seventy samples of overbank and channel‐edge sediments were collected at 35 sites along the River Swale. Inductively coupled plasma‐mass spectrometry was used to measure contaminant metal concentrations in the 2000–63 µm (sand) and <63 µm (silt and clay) size fractions. In both the channel‐edge and overbank sediments collected from the upper and middle reaches of the River Swale, concentrations of lead, zinc and cadmium were found to exceed MAFF guidelines. Highest concentrations correspond to the input of contaminated material from intensively mined tributaries, and elevated levels can be observed 5–10 km downstream of these inputs. This indicates that the remobilization of contaminated material during major flood events is potentially a serious problem for activities such as agriculture that utilize the Swale floodplain. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
319.
Sui Linhui Holman Gordon D. Dennis Brian R. Krucker Säm Schwartz Richard A. Tolbert Kim 《Solar physics》2002,210(1-2):245-259
We have analyzed a C7.5 limb flare observed by RHESSI on 20 February 2002. The RHESSI images appear to show two footpoints
and a loop-top source. Our goal was to determine if the data are consistent with a simple steady-state model in which high-energy
electrons are continuously injected at the top of a semicircular flare loop. A comparison of the RHESSI images with simulated
images from the model has made it possible for us to identify spurious sources and fluxes in the RHESSI images. We find that
the RHESSI results are in many aspects consistent with the model if a thermal source is included between the loop footpoints,
but there is a problem with the spectral index of the loop-top source. The thermal source between the footpoints is likely
to be a low-lying loop interacting with the northern footpoint of a higher loop containing the loop-top source. 相似文献
320.
Hanna Hadler Andreas Vött Timo Willershäuser Dennis Wilken Ruth Blankenfeldt Claus von Carnap-Bornheim Kurt Emde Peter Fischer Ulf Ickerodt Stefanie Klooß Bente Majchczack Lea Obrocki Wolfgang Rabbel 《地球表面变化过程与地形》2021,46(15):3228-3251
In ad 1362, a major storm surge drowned wide areas of cultivated medieval marshland along the north-western coast of Germany and turned them into tidal flats. This study presents a new methodological approach for the reconstruction of changing coastal landscapes developed from a study site in the Wadden Sea of North Frisia. Initially, we deciphered long-term as well as event-related short-term geomorphological changes, using a geoscientific standard approach of vibracoring, analyses of sedimentary, geochemical and microfaunal palaeoenvironmental parameters and radiocarbon dating. In a next step, Direct Push (DP)-based Cone Penetration Testing (CPT) and the Hydraulic Profiling Tool (HPT) were applied at vibracore locations to obtain in situ high-resolution stratigraphic data. In a last step, multivariate linear discriminant analysis (LDA) was successfully applied to efficiently identify different sedimentary facies (e.g., fossil marsh or tidal flat deposits) from the CPT and HPT test dataset, to map the facies' lateral distribution, also in comparison to reflection seismic measurements and test their potential to interpolate the borehole and CPT/HPT data. The training dataset acquired for the key site from coring and DP sensing finally allows an automated facies classification of CPT/HPT data obtained elsewhere within the study area. The new methodological approach allowed a detailed reconstruction of the local coastal landscape development in the interplay of natural marsh formation, medieval land reclamation and storm surge-related land losses. 相似文献