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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
Diets Of Baird’S Beaked Whales, Berardius Bairdii, In The Southern Sea Of Okhotsk And Off The Pacific Coast Of Honshu, Japan, William A. Walker, James G. Mead, Robert L. Brownell Jr.
Diets Of Baird’S Beaked Whales, Berardius Bairdii, In The Southern Sea Of Okhotsk And Off The Pacific Coast Of Honshu, Japan, William A. Walker, James G. Mead, Robert L. Brownell Jr.
United States Department of Commerce: Staff Publications
Stomach contents were analyzed from 127 Baird’s beaked whales, Berardizls bairdii, taken in coastal waters of Japan. During late July-August of 1985- 1987, 1989, and 1991, 107 samples were collected from off the Pacific coast of Honshu. An additional 20 samples were collected from whales taken in the southern Sea of Okhotsk during late August-September of 1988 and 1989. Prey identification using fish otoliths and cephalopod beaks revealed the whales fed primarily on deep-water gadiform fishes and cephalopods in both regions. Prey species diversity and the percentage of cephalopods and fish differed between the two regions. Off the Pacific …
The Ideal Lead Time For Tornado Warnings - A Look From The Customer’S Perspective, Rick Ewald, Jared L. Guyer
The Ideal Lead Time For Tornado Warnings - A Look From The Customer’S Perspective, Rick Ewald, Jared L. Guyer
United States Department of Commerce: Staff Publications
Improving the amount of advanced warning time (lead time) for tornado warnings is one of the goals spelled out in the National Weather Service (NWS) Vision 2005 Strategic Plan (1999). Since the beginning of the NWS modernization effort, tornado warning lead times have increased from four to ten minutes, with the goal of 15 mi nutes set for 2005. In concert with increasing lead times, the NWS also has goals in place for increasing the probability of detection (POD) while decreasing the false alarm rate (FAR).
Accomplishing these goals will be no easy task. Rothfusz (2000) noted that forecasters may …
A Case Of Supercell Intensification Along A Preexisting Boundary – Clay County Nebraska Tornado Of 22 September 2001, Jared Guyer
A Case Of Supercell Intensification Along A Preexisting Boundary – Clay County Nebraska Tornado Of 22 September 2001, Jared Guyer
United States Department of Commerce: Staff Publications
During the early evening hours of 22 September 2001, a supercell thunderstorm developed in south central Nebraska along an advancing cold front. The supercell initially produced an F1 tornado (Fujita 1971) in northern Clay County, Nebraska.
As the supercell propagated southeastward through Clay County, it rapidly intensified and produced a second, much stronger, tornado. The tornado produced F3 damage to three farmsteads in rural Clay County, Nebraska, along a 13 km path. The tornado was over one half km in diameter for much of its lifetime.
In accordance with research involving low-level boundaries and tornadic storms (Maddox et al. 1980; …
Monitoring The Prey-Field Of Marine Predators: Combining Digital Imaging With Datalogging Tags, Sascha Hooker, Ian L. Boyd, Mark Jessop, Oliver Cox, John Blackwell, Peter Boveng, John Bengston
Monitoring The Prey-Field Of Marine Predators: Combining Digital Imaging With Datalogging Tags, Sascha Hooker, Ian L. Boyd, Mark Jessop, Oliver Cox, John Blackwell, Peter Boveng, John Bengston
United States Department of Commerce: Staff Publications
There is increasing interest in the diving behavior of marine mammals. However, identifying foraging among recorded dives often requires several assumptions. The simultaneous acquisition of images of the prey encountered, together with records of diving behavior will allow researchers to more fully investigate the nature of subsurface behavior. We tested a novel digital camera linked to a time-depth recorder on Antarctic fur seals (Arctocephalus gazella). During the austral summer 2000-2001, this system was deployed on six lactating female fur seals at Bird Island, South Georgia, each for a single foraging trip. The camera was triggered at depths greater …
A Study Of Various Thermodynamic And Wind Variables Associated With Tornadic Supercells Exhibiting Atypical Motion, Aaron Johnson
A Study Of Various Thermodynamic And Wind Variables Associated With Tornadic Supercells Exhibiting Atypical Motion, Aaron Johnson
United States Department of Commerce: Staff Publications
Recent research into supercells has focused on narrowing the number of important storm processes that lead to these storms. For years it has been known that supercells generally deviate slightly to the left or right of the mean wind, but that in some rare cases, supercells move in a very atypical direction. For example, Corfidi (1998) examined the conditions present for the Jarrell, Texas tornado, which exhibited such an atypical motion, and found the environment to be extremely unstable with weak storm-relative helicity. He also found that the southwest movement of the Jarrell, TX storm was closely tied to the …
Influence Of Seismic Surveys On Western Gray Whales Off Sakhalin Island, Russia In 2001, David W. Weller, Yulia V. Ivashchenko, Grigory A. Tsidulko, Alexander M. Burdin, Robert L. Brownell Jr.
Influence Of Seismic Surveys On Western Gray Whales Off Sakhalin Island, Russia In 2001, David W. Weller, Yulia V. Ivashchenko, Grigory A. Tsidulko, Alexander M. Burdin, Robert L. Brownell Jr.
United States Department of Commerce: Staff Publications
Western gray whales (Eschrichtius robustus) aggregate off the northeastern coast of Sakhalin Island, Russia during summer-autumn to feed on benthic and near-benthic prey. During summer 2001, 3D seismic surveys were conducted during a six-week period in known gray whale foraging areas off Sakhalin Island. To test the hypothesis that the distribution of gray whales on the feeding ground would shift away from nearby seismic surveying, we examined the number of whales and number of pods (dependent variables) sighted during systematic scans in relation to three independent variables (i.e. preseismic, seismic, post-seismic). Results showed the main effect of condition …
Intermittent Turbulence Associated With A Density Current Passage In The Stable Boundary Layer, Jielun Sun, Sean P. Burns, Donald H. Lenschow, Robert Banta, Rob Newsom, Richard Coulter, Stephen Fraiser, Carmen Nappo, Joan Cuxart, William Blumen, Xuhui Lee, Xin-Zhang Hu
Intermittent Turbulence Associated With A Density Current Passage In The Stable Boundary Layer, Jielun Sun, Sean P. Burns, Donald H. Lenschow, Robert Banta, Rob Newsom, Richard Coulter, Stephen Fraiser, Carmen Nappo, Joan Cuxart, William Blumen, Xuhui Lee, Xin-Zhang Hu
United States Department of Commerce: Staff Publications
Using the unprecedented observational capabilities deployed during the Cooperative Atmosphere-Surface Exchange Study-99 (CASES-99), we found three distinct turbulence events on the night of 18 October 1999, each of which was associated with different phenomena: a density current, solitary waves, and downward propagating waves from a low-level jet. In this study, we focus on the first event, the density current and its associated intermittent turbulence. As the cold density current propagated through the CASES-99 site, eddy motions in the upper part of the density current led to periodic overturning of the stratified flow, local thermal instability and a downward diffusion of …
Dynamics Of The Lake Michigan Food Web, 1970–2000, Charles P. Madenjian, Gary L. Fahnenstiel, Thomas H. Johengen, Thomas F. Nalepa, Henry A. Vanderploeg, Guy W. Fleischer, Philip J. Schneeberger, Darren M. Benjamin, Emily B. Smith, James R. Bence, Edward S. Rutherford, Dennis S. Lavis, Dale M. Robertson, David J. Jude, Mark P. Ebener
Dynamics Of The Lake Michigan Food Web, 1970–2000, Charles P. Madenjian, Gary L. Fahnenstiel, Thomas H. Johengen, Thomas F. Nalepa, Henry A. Vanderploeg, Guy W. Fleischer, Philip J. Schneeberger, Darren M. Benjamin, Emily B. Smith, James R. Bence, Edward S. Rutherford, Dennis S. Lavis, Dale M. Robertson, David J. Jude, Mark P. Ebener
United States Department of Commerce: Staff Publications
Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in …
Estimation Of Depth-Area Relationships Using Radar-Rainfall Data, S. Rocky Durrans, Lesley T. Julian, Michael Yekta
Estimation Of Depth-Area Relationships Using Radar-Rainfall Data, S. Rocky Durrans, Lesley T. Julian, Michael Yekta
United States Department of Commerce: Staff Publications
Depth-area relationships, such as those published by the National Weather Service in TP 40 and the NOAA Atlas 2, enable conversion of point rainfall depths to areal average depths for the same storm duration and recurrence interval. This problem of conversion is most germane to hydrologic analyses for moderate to large drainage basins, where point rainfall depths are not representative of the spatial distribution of a storm event. Historically, depth-area relationships have been developed on the basis of data from dense networks of recording gauges. However, with the ongoing accumulation of radar-rainfall records, radar-rainfall data represent an alternative to gauging …
Application And National Geographic Information System Database To Support Two-Year Flood And Threshold Runoff Estimates, Seann Reed, Dennis Johnson, Timothy Sweeney
Application And National Geographic Information System Database To Support Two-Year Flood And Threshold Runoff Estimates, Seann Reed, Dennis Johnson, Timothy Sweeney
United States Department of Commerce: Staff Publications
A computer application and national geospatial database have been developed to support the calculation of flooding flow (Qf) and threshold runoff across the conterminous United States and Alaska. Flooding flow is the flow required to cause a stream to slightly overflow its bank and cause damage. Threshold runoff [L], defined as the depth of runoff required to cause flooding, is computed as flooding flow divided by the unit hydrograph peak flow. A key assumption in this work is that the two-year return flood (Q2) is a useful surrogate for flooding flow. The application described here computes …
Chemical Contaminants In Juvenile Gray Whales (Eschrichtius Robustus) From A Subsistence Harvest In Arctic Feeding Grounds, Karen L. Tilbury, John E. Stein, Cheryl A. Krone, Robert L. Brownell Jr., S.A. Blokhin, Jennie L. Bolton, Don W. Ernest
Chemical Contaminants In Juvenile Gray Whales (Eschrichtius Robustus) From A Subsistence Harvest In Arctic Feeding Grounds, Karen L. Tilbury, John E. Stein, Cheryl A. Krone, Robert L. Brownell Jr., S.A. Blokhin, Jennie L. Bolton, Don W. Ernest
United States Department of Commerce: Staff Publications
Gray whales are coastal migratory baleen whales that are benthic feeders. Most of their feeding takes place in the northern Pacific Ocean with opportunistic feeding taking place during their migrations and residence on the breeding grounds. The concentrations of organochlorines and trace elements were determined in tissues and stomach contents of juvenile gray whales that were taken on their Arctic feeding grounds in the western Bering Sea during a Russian subsistence harvest. These concentrations were compared to previously published data for contaminants in gray whales that stranded along the west coast of the US during their northbound migration. Feeding in …
The Western Gray Whale: A Review Of Past Exploitation, Current Status And Potential Threats, David Weller, Alexander Burdin, Bernd Wursig, Barbara Taylor, Robert L. Brownell Jr.
The Western Gray Whale: A Review Of Past Exploitation, Current Status And Potential Threats, David Weller, Alexander Burdin, Bernd Wursig, Barbara Taylor, Robert L. Brownell Jr.
United States Department of Commerce: Staff Publications
Gray whales (Eschrichtius robustus) occur along the eastern and western coastlines of the North Pacific as two geographically isolated populations and have traditionally been divided into the eastern (California-Chukchi) and western (Korean-Okhotsk) populations. Recent molecular comparisons confirm, based on differences in haplotypic frequencies, that these populations are genetically separated at the population-level. Both populations were commercially hunted, but only the eastern gray whale has returned to near pre-exploitation numbers. In contrast, the western population remains highly depleted, shows no apparent signs of recovery and its future survival remains uncertain. Research off Sakhalin Island, Russia between 1995 and 1999 …
Dispersal And Emerging Ecological Impacts Of Ponto-Caspian Species In The Laurentian Great Lakes, Henry A. Vanderploeg, Thomas F. Nalepa, David J. Jude, Edward L. Mills, Kristen T. Holeck, James R. Liebig, Igor A. Grigorovich, Henn Ojaveer
Dispersal And Emerging Ecological Impacts Of Ponto-Caspian Species In The Laurentian Great Lakes, Henry A. Vanderploeg, Thomas F. Nalepa, David J. Jude, Edward L. Mills, Kristen T. Holeck, James R. Liebig, Igor A. Grigorovich, Henn Ojaveer
United States Department of Commerce: Staff Publications
We describe, explain, and “predict” dispersal and ecosystem impacts of six Ponto-Caspian endemic species that recently invaded the Great Lakes via ballast water. The zebra mussel, Dreissena polymorpha, and quagga mussel, Dreissena bugensis, continue to colonize hard and soft substrates of the Great Lakes and are changing ecosystem function through mechanisms of ecosystem engineering (increased water clarity and reef building), fouling native mussels, high particle filtration rate with selective rejection of colonial cyanobacteria in pseudofeces, alteration of nutrient ratios, and facilitation of the rapid spread of their Ponto-Caspian associates, the benthic amphipod Echinogammarus ischnus and the round goby, …