Physical Sciences and Mathematics Commons^™

Reply To Comment By Sushil K. Singh On "A Concept Of Maximum Stream Depletion Rate For Leaky Aquifers In Alluvial Valleys", Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

Vitaly A. Zlotnik's reply to the comment by Sushil K. Singh on Zlotnik's "A concept of maximum stream depletion rate for leaky aquifers in alluvial valleys."

Cloud-To-Ground Lightning Production In Strongly Forced, Low-Instability Convective Lines Associated With Damaging Wind, Matthew S. Van Den Broeke, David M. Schultz, Robert H. Johns, Jeffry S. Evans, John E. Hales

Department of Earth and Atmospheric Sciences: Faculty Publications

During 9–11 November 1998 and 9–10 March 2002, two similar convective lines moved across the central and eastern United States. Both convective lines initiated over the southern plains along strong surface-based cold fronts in moderately unstable environments. Both lines were initially associated with cloud-to-ground (CG) lightning, as detected by the National Lightning Detection Network, and both events met the criteria to be classified as derechos, producing swaths of widespread damaging wind. After moving into areas of marginal, if any, instability over the upper Midwest, CG lightning production ceased or nearly ceased, although the damaging winds continued. The 9 March 2002 …

Holocene Hydrologic Variation At Lake Titicaca, Bolivia/Peru, And Its Relationship To North Atlantic Climate Variation, P. A. Baker, Sherilyn C. Fritz, J. Garland, E. Ekdahl

Department of Earth and Atmospheric Sciences: Faculty Publications

A growing number of sites in the Northern Hemisphere show centennial- to millennial-scale climate variation that has been correlated with change in solar variability or with change in North Atlantic circulation. However, it is unclear how (or whether) these oscillations in the climate system are manifest in the Southern Hemisphere because of a lack of sites with suitably high sampling resolution. In this paper, we reconstruct the lake-level history of Lake Titicaca, using the carbon isotopic content of sedimentary organic matter, to evaluate centennial-to millennial-scale precipitation variation and its phasing relative to sites in the Northern Hemisphere. The pattern and …

Aquitard Effect On Drawdown In Water Table Aquifers, Vitaly A. Zlotnik, Hongbin Zhan

Department of Earth and Atmospheric Sciences: Faculty Publications

The effects of an aquitard on drawdown in an overlying unconfined aquifer can be represented by a drainage-type term at the aquitard-aquifer interface. The functional form of this boundary condition is similar to the Boulton-Neuman boundary condition used for water table aquifers except the kernel contains an inverse square root of time instead of a negative exponential. Type curves using the new boundary condition were obtained in semianalytical form. Examples for several representative conditions show that the effect of the underlying aquitard can contribute to the type curve at early and intermediate times, but the effect becomes negligible at late …

Women In Oceanography: Women Of The Academy And The Sea, Suzanne O'Connell, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

Women have played an active role in all areas of oceanography. Defining the number of women oceanographers is not an easy task because the discipline is so broad and the boundaries between subdisciplines are not always distinct.

The Maastrichtian Record From Shatsky Rise (Northwest Pacific): A Tropical Perspective On Global Ecological And Oceanographic Changes, Tracy D. Frank, Deborah J. Thomas, R. Mark Leckie, Michael A. Arthur, Paul R. Brown, Kelly Jones, Jackie A. Lees

Department of Earth and Atmospheric Sciences: Faculty Publications

We present new isotopic and micropaleontological data from a depth transect on Shatsky Rise that record the response of the tropical Pacific to global biotic and oceanographic shifts during the mid-Maastrichtian. Results reveal a coupling between the upper ocean, characterized by a weak thermocline and low to intermediate productivity, and intermediate waters. During the earliest Maastrichtian, oxygen and neodymium isotope data suggest a significant contribution of relatively warm intermediate water from the North Pacific. Isotopic shifts through the early Maastrichtian suggest that this warmer water mass was gradually replaced by cooler waters originating in the Southern Ocean. Although the cooler …

Groundwater Irrigation In The Development Of The Grand Prairie Rice Industry, 1896-1950, John B. Gates

Department of Earth and Atmospheric Sciences: Faculty Publications

Elucidates some of the ways in which groundwater and groundwater irrigation have affected the Grand Prairie's rice industry over time and conversely how the development of the industry has altered the region's groundwater conditions. Concentrates on aspects of the industry's history that have often been overlooked in favor of rice cultivation's social dimensions and consider hydrological systems not just as resources awaiting exploitation or as simple constraints on production but as variables whose roles and effects can change over time.

Evidence For Marine Influence On A Low-Gradient Coastal Plain: Ichnology And Invertebrate Paleontology Of The Lower Tongue River Member (Fort Union Formation, Middle Paleocene), Western Williston Basin, U.S.A., Edward S. Belt, Neil E. Tibert, H. Allen Curran, John A. Diemer, Joseph H. Hartman, Timothy J. Kroeger, David M. Harwood

Department of Earth and Atmospheric Sciences: Faculty Publications

The Paleocene Tongue River Member of the Fort Union Formation contains trace-fossil associations indicative of marine influence in otherwise freshwater facies. The identified ichnogenera include: Arenicolites, Diplocraterion, Monocraterion, Ophiomorpha, Rhizocorallium, Skolithos linearis, Teichichnus, Thalassinoides, and one form of uncertain affinity. Two species of the marine diatom Coscinodiscus occur a few meters above the base of the member. The burrows occur in at least five discrete, thin, rippled, fine-grained sandstone beds within the lower 85 m of the member west of the Cedar Creek anticline (CCA) in the Signal Butte, Terry Badlands, and Pine Hills areas. T wo discrete burrowed …

New Stratigraphic Subdivision, Depositional Environment, And Age Estimate For The Upper Cretaceous Djadokhta Formation, Southern Ulan Nur Basin, Mongolia, Demberelyin Dashzeveg, Lowell Dingus, David B. Loope, Carl C. Swisher Iii, Togtokh Dulam, Mark R. Sweeney

Department of Earth and Atmospheric Sciences: Faculty Publications

Studies of key and newly discovered sections of the Upper Cretaceous Djadokhta Formation along the southern margin of the Ulan Nur Basin allow a new subdivision based on lithology. The formation and its members were mapped at both Bayn Dzak, an area that includes the Flaming Cliffs, and Tugrugyin Shireh, an area about 50 km to the northwest of Bayn Dzak. Stratigraphic sections at both localities were remeasured. The considerably enlarged formation comprises a lower Bayn Dzak Member, dominated by moderate reddish orange sands with subordinate mudstone units, and an upper Tugrugyin Member, composed of pale orange to light gray …

Calcareous Nannofossil Evidence For The Existence Of The Gulf Stream During The Late Maastrichtian, David K. Watkins, Jean M. Self-Trail

Department of Earth and Atmospheric Sciences: Faculty Publications

Upper Maastrichtian calcareous nannofossil assemblages, from eight cores on the South Carolina Coastal Plain (onshore set) and three deep sea drilling sites from the continental slope and abyssal hills (offshore set), were analyzed by correlation and principal component analysis to examine the ancient surface water thermal structure. In addition, a temperature index derived from independently published paleobiogeographic information was applied to the sample data. All three methods indicate a strong separation of the samples into onshore and offshore sets, with the offshore data set exhibiting significantly warmer paleotemperatures. The great disparity between these two sample sets indicates that there was …

Reply To Comment By H. Lough, Department Of Civil Engineering, University Of Canterbury, Christchurch, New Zealand, On The Paper “Stream Depletion Predictions Using Pumping Test Data From A Heterogeneous Stream–Aquifer System (A Case Study From The Great Plains, Usa)”, S. J. Kollet, Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

1. General remark

2. The study by Kollet and Zlotnik (2003)

3. Remark on the explanation of the drawdown behavior

4. Remark on the re-analysis of the data from piezometer C2d

5. Summary

Vegetation And Climate Change On The Bolivian Altiplano Between 108,000 And 18,000 Years Ago, Alex Chepstow-Lusty, Mark B. Bush, Michael R. Frogley, Paul A. Baker, Sherilyn C. Fritz, James Aronson

Department of Earth and Atmospheric Sciences: Faculty Publications

A 90,000-yr record of environmental change before 18,000 cal yr B.P. has been constructed using pollen analyses from a sediment core obtained from Salar de Uyuni (3653 m above sea level) on the Bolivian Altiplano. The sequence consists of alternating mud and salt, which reflect shifts between wet and dry periods. Low abundances of aquatic species between 108,000 and 50,000 yr ago (such as Myriophyllum and Isoëtes) and marked fluctuations in Pediastrum suggest generally dry conditions dominated by saltpans. Between 50,000 yr ago and 36,000 cal yr B.P., lacustrine sediments become increasingly dominant. The transition to the formation of …

Calcareous Nannoplankton Response To Late Albian Oceanic Anoxic Event 1d In The Western North Atlantic, David K. Watkins, Matthew J. Cooper, Paul A. Wilson

Department of Earth and Atmospheric Sciences: Faculty Publications

Well-preserved nannofossil and stable isotope records from the mid-Cretaceous of Ocean Drilling Project Leg 171B (western North Atlantic) indicate cyclical, productivity-based variations in surface water characteristics, suggesting orbitally paced changes in upwelling intensity and the strength of deep mixing associated with oceanic anoxic event (OAE)1d. Paleontologic and isotopic evidence suggest that collapse of upper water column stratification associated with OAE1d was preceded by approximately 1 m.y. of progressively decreasing water column stability and increasing surface water fertility. Thirteen species went extinct during a short (ca. 200 k.y.) interval associated with OAE1d. Nine of these have morphological characters suggesting adaptation to …

In Memoriam: John Platt Bradbury (1936–2005), Walter Dean, Sherilyn C. Fritz, Cathy Whitlock, William Watts

Department of Earth and Atmospheric Sciences: Faculty Publications

John Platt Bradbury, a former United States Geological Survey (USGS) geologist, and a long time and much valued editorial board member for the Journal of Paleolimnology, died of cancer (abdominal mesothelioma) on August 15, 2005, in the log home that he and his wife Vera Markgraf built in the mountains near Monte Vista, Colorado. Platt’s interest in paleolimnology developed during his graduate school years at the University of New Mexico, working with Roger Anderson and Walt Dean. He received his Ph.D. in 1967. He went on to do post-doctoral research at Yale University under G. Evelyn Hutchinson and then …

Do Meteorologists Suppress Thunderstorms? Radar-Derived Statics And The Behavior Of Moist Convection, Matthew D. Parker, Jason C. Knievel

Department of Earth and Atmospheric Sciences: Faculty Publications

Most meteorologists are acquainted with the no- tion of a weather hole—that is, a place that receives less exciting weather than does its surroundings. Exciting weather takes many forms, but when people use the term weather hole, they tend to mean a place that thunderstorms often barely miss, or near which approaching storms often dissipate. For this paper, that is the meaning we adopt.

In our experience, many meteorologists and lay weather enthusiasts genuinely believe that they live in weather holes, and this belief, almost without fail, seems to stem from countless hours spent gazing at displays of radar reflectivity. …

High-Resolution Ocean Color Remote Sensing Of Benthic Habitats: A Case Study At The Roatan Island, Honduras, Deepak R. Mishra, Sunil G. Narumalani, Donald Rundquist, Merlin P. Lawson

Department of Earth and Atmospheric Sciences: Faculty Publications

Natural resource managers clamor for detailed reef habitat maps for monitoring smaller scale disturbances in reef communities. Coastal ocean color remote sensing techniques permit benthic habitats to be explored with higher resolution than ever before. The objective of this research was to develop an accurate benthic habitat map for an area off the northwest coast of Roatan Island, Honduras, using high-resolution multispectral IKONOS data. Atmospheric (Rayleigh and aerosol path radiance) and water column corrections (water depth and water column attenuation) were applied to the imagery, making it a robust method for mapping benthic habitats. Water depth for each pixel was …

Holocene Paleoecology Along The Blekinge Coast, Southeast Sweden, And Implications For Climate And Sea-Level Changes, Shi-Yong Yu, Björn E. Berglund, Per Sandgren, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

To investigate the Holocene vegetation history and shoreline displacement along the southeastern Swedish coast, two radiocarbon dated pollen, macrofossil, and mineral magnetic sequences were studied in the western Blekinge coast: Hunnemara Lake and Smygen Bay. Both pollen records show mosaic vegetation with grasslands, heaths and woodlands prior to 11,300 cal. BP. Pinus-dominated mixed forest was initially established by 11,000 cal. BP. By 10,000 cal. BP, mixed forest with higher species diversity was fully established. Expansion of broad-leaved trees began at about 8,600 cal. BP, indicating the onset of the mid-Holocene thermal maximum in Scandinavia. Following the Ulmus decline ~5,800 …

Vertical Movement Of Water In A High Plains Aquifer Induced By A Pumping Well, Xunhong Chen, Yanfeng Yin, James W. Goeke, Robert F. Diffendal Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

Field observation and numerical simulations were carried out to evaluate the hydraulic relationship between the shallow and deep aquifer of a High Plains Aquifer system, in which shallow and deep aquifers are separated by an aquitard. Pumping from the lower aquifer resulted in a small drawdown in the upper aquifer and a larger drawdown in the aquitard; pumping from the shallow aquifer caused a small drawdown in the aquitard and the deep aquifer. Analysis of pumping test data gives the values of the hydraulic conductivity of the aquitard and the deep aquifer. Long-term observation of groundwater levels in the shallow …

Performance Of Quality Assurance Procedures For An Applied Climate Information System, K. G. Hubbard, S. Goddard, Bill Sorensen, N. Wells, Thomas Osugi

Department of Earth and Atmospheric Sciences: Faculty Publications

Valid data are required to make climate assessments and to make climate-related decisions. The objective of this paper is threefold: to introduce an explicit treatment of Type I and Type II errors in evaluating the performance of quality assurance procedures, to illustrate a quality control approach that allows tailoring to regions and subregions, and to introduce a new spatial regression test. Threshold testing, step change, persistence, and spatial regression were included in a test of three decades of temperature and precipitation data at six weather stations representing different climate regimes. The magnitude of thresholds was addressed in terms of the …