Atmospheric Sciences Commons^™

An Analysis Of Simulated Long-Term Soil Moisture Data For Three Land Uses Under Contrasting Hydroclimatic Conditions In The Northern Great Plains, Rezaul Mamood, Kenneth G. Hubbard

High Plains Regional Climate Center: Staff Publications

Soil moisture (SM) plays an important role in land surface and atmosphere interactions. It modifies energy balance near the surface and the rate of water cycling between land and atmosphere. The lack of observed SM data prohibits understanding of SM variations at climate scales under varying land uses. However, with simulation models it is possible to develop a long-term SM dataset and study these issues. In this paper a water balance model is used to provide a quantitative assessment of SM climatologies for three land uses, namely, irrigated corn, rain-fed corn, and grass, grown under three hydroclimatic regimes in Nebraska. …

Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Measurements of methyl chloride (CH3Cl) in Antarctic polar ice and firn air are used to describe the variability of atmospheric CH3Cl during the past 300 years. Firn air results from South Pole and Siple Dome suggest that the atmospheric abundance of CH3Cl increased by about 10% in the 50 years prior to 1990. Ice core measurements from Siple Dome provide evidence for a cyclic natural variability on the order of 10%, with a period of about 110 years in phase with the 20th century rise inferred from firn air. Thus, the CH3Cl increase measured in firn air may largely be …

Modeled And Observed Empirical Orthogonal Functions Of Currents In The Yucatan Channel, Gulf Of Mexico, Lie-Yauw Oey, Tal Ezer, Wilton Sturges

CCPO Publications

Candela et al. [2003] have reported empirical orthogonal function (EOF) analyses based on 23-month current-meter and acoustic Doppler current profiler measurements in the Yucatan Channel. Those authors noted the difference between EOFs obtained from observations and their z-level models and EOFs calculated by Ezer et al. [2003] from the results of a terrain-following model. Here a new analysis is reported that explains this difference, and that also suggests the importance of shelf-edge meander mode of the core Loop Current in the channel. We show that the terrain-following model gives EOFs with characteristics similar to those observed when data from the …

Sources And Cycling Of Carbonyl Sulfide In The Sargasso Sea, Gregory A. Cutter, Lynda S. Cutter, Katherine C. Filippino

OES Faculty Publications

The cycling of the radiatively important gas carbonyl sulfide (OCS) was studied in surface waters of the Sargasso Sea. In August 1999, surface OCS concentrations averaged 8.6 pmol L^-1, showed minor diel variations, and varied little with depth. An OCS precursor, total dissolved organic sulfur (DOS), was lowest at the surface (40 nmol L^-1) and increased with depth. The photoproduction rate of OCS from in situ incubations averaged 9.6 pmol L^-1 h^-1, whereas dark production was 7.0 pmol L^-1 h^-1. Apparent quantum yields were 10^-5-10^-7 from 313-436 …

New Evidence For Enhanced Ocean Primary Production Triggered By Tropical Cyclone, I. Lin, W. Timothy Liu, Chun-Chieh Wu, George T. F. Wong, Chuanmin Hu, Zhiqiang Chen, Wen-Der Liang, Yih Yang, Kon-Kee Liu

OES Faculty Publications

[1] New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long-speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai-Tak passed over the South China Sea (SCS). During its short 3-day stay, Kai-Tak triggered an average 30-fold increase in surface chlorophyll-a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2-4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long-neglected contribution of tropical cyclones to SCS's annual new production may …

A 700-Year Record Of Atmospheric Circulation Developed From The Law Dome Ice Core, East Antarctica, Joseph M. Souney Jr, Paul A. Mayewski, Ian D. Goodwin, David Meeker, Vin Morgan, Mark Aj Curran, Tas D. Van Ommen, Anne S. Palmer

All Materials

A 700-year, high-resolution, multivariate ice core record from Dome Summit South (DSS) (66°46′S, 112°48′E; 1370 m), Law Dome, is used to investigate sea level pressure (SLP) variability in the region of East Antarctica. Empirical orthogonal function (EOF) analysis reveals that the first EOF (LDEOF1) of the combined glaciochemical, oxygen isotope ratio, and accumulation rate record from DSS represents most of the variability in sea salt seen in the record. LDEOF1 is positively correlated (at least 95% confidence level) to instrumental June mean SLP across most of East Antarctica. Over the last 700 years, LDEOF1 levels at Law Dome were the …

Land Use Change And Modification Of Near-Surface Thermal Records In The Northern Great Plains, Rezaul Mahmood, Ken Hubbard, Christy Carlson

High Plains Regional Climate Center: Staff Publications

The North American Great Plains have experienced a rapid overturning of natural grasslands to agricultural land use over the last century. Moreover, in some areas more than 80% of the land use has changed from dry land to irrigated agriculture during the second half of the twentieth century. It is speculated that these changes have modified near-surface atmospheric condition and our modeling study seems to support this. To identify changes in land surface- atmospheric modifications we have applied a soil moistureenergy balance model at three locations in Nebraska: Mead, York, and McCook. The model was applied for three land uses …

Dark Production: A Significant Source Of Oceanic Cos, M. Von Hobe, Gregory A. Cutter, A. J. Kettle, M. O. Andreae

OES Faculty Publications

Carbonyl sulfide (COS) in air and dissolved in seawater was determined during a cruise in August 1999 in the Sargasso Sea in the northwest Atlantic Ocean. Dissolved concentrations at the sea surface displayed only a weak diel cycle with a mean of 8.6 ± 2.8 pmol dm⁻³ owing to low abundance of photochemical precursors and high temperatures causing rapid hydrolysis. Depth profiles measured over the oceanic mixed layer revealed significant vertical gradients of COS concentration with higher values at the surface, suggesting that the rate of photochemical production at the surface exceeds the rate of vertical mixing. The mean …

A Guide To Floodplain Cattle Fencing, Department Of Agriculture, Western Australia, Main Roads, Western Australia

Animal production and livestock published reports

A seminar and workshop was held at Fitzroy Crossing in October 1993 to address the consequences of flooding to landholders and communities.

Damage to flood plain fencing was identified as one of the major concerns to landholders.

An outcome from the workshop was the decision to draw on local knowledge and collate information on options for fence and floodgate designs.

This information was to be made available to land holders and other interested parties - hence this publication.

Periodic And Homoclinic Orbits In A Toy Climate Model, M. Toner, A. D. Kirwan Jr.

Mathematics & Statistics Faculty Publications

A two dimensional system of autonomous nonlinear ordinary differential equations models glacier growth and temperature changes on an idealized planet. We apply standard perturbative techniques from dynamical systems theory to study small amplitude periodic orbits about a constant equilibrium. The equations are put in cononical form and the local phase space topology is examined. Maximum and minimum periods of oscillation are obtained and related to the radius of the orbit. An adjacent equilibrium is shown to have saddle character and the inflowing and outflowing manifolds of this saddle are studied using numerical integration. The inflowing manifolds show the region of …

Invariant Manifolds Of A Toy Climate Model, Michael Toner

Mathematics & Statistics Theses & Dissertations

According to astronomical theory, ice ages are caused by variations in the Earth's orbit. However, ice core data shows strong fluctuations in ice volume at a low frequency not significantly present in orbital variations. To understand how this might occur, the dynamics of a two dimensional nonlinear differential equation representing glacier/temperature interaction of an idealized climate was studied. Self sustained oscillation of the autonomous equation was used to model the internal mechanisms that could produce these fluctuations. Periodic parametric modulation of a damped internal oscillation was used to model periodic climate response at double the external modulation period. Both phenomena …

A Comparison Of No And N20 Production By The Autophic Nitrifier Nitrosomonas Europaea And The Heterotrophic Nitrifier Alcaligenes Faecalis, Iris C. Anderson, Mark Poth, Julie Homstead, David J. Burdige

OES Faculty Publications

Soil microorganisms are important sources of the nitrogen trace gases NO and N₂O for the atmosphere. Present evidence suggests that autotrophic nitrifiers such as Nitrosomonas europaea are the primary producers of NO and N₂O in aerobic soils, whereas denitrifiers such as Pseudomonas spp. or Alcaligenes spp. are responsible for most of the NO and N₂O emissions from anaerobic soils. It has been shown that Alcaligenes faecalis, a bacterium common in both soil and water, is capable of concomitant heterotrophic nitrification and denitrification. This study was undertaken to determine whether heterotrophic nitrification might be …

Emission Rates Of Co2 From Plume Measurements., D. M. Harris, M. Sato, T. J. Casadevall, William I. Rose, T. J. Bornhorst

Michigan Tech Publications, Part 1

Most of the CO2 that emanated from Mount St. Helens became part of the gas plume as it moved away from the volcano. An airborne technique was developed for continuous sampling and infrared analysis for CO2 in the plume. The CO2-emission rates were determined by measuring the area, the horizontal velocity, and the CO2 concentration anomaly in vertical cross sections of the plume The emission rate varied from 2100 t/day to about 22 000 t/day.-from Author

Radar Observations Of Ash Eruptions, D. M. Harris, William I. Rose, R. Roe, M. R. Thompson

Michigan Tech Publications, Part 1

Radar systems located at Portland, Oreg., Seattle, Wash., and near Spokane, Wash., have been used extensively for observations of ash clouds from explosive volcanic eruptions at Mount St. Helens during 1980. Eruption clouds are composed of silicate particles and are therefore detectable by radar. Radar observations can be made at night and in overcast weather when conventional observations of eruptions are difficult.-from Authors

Grain Legume Agronomy 1976-1977, G H. Walton

Experimental Summaries - Plant Research

76B1, Lupin agronomy, high rainfall area.

CB49, Lupin crop establishment methods.

76JE7, Lupin agronomy and soil fertility improvement.

74MO11, Seedling regeneration.

75MO7, Pasture establishment under unicrop and soil fertility improvement.

76MO13, L. cosentinii cv CB49 agronomy.

76MO14, Amino acid sequence study in the maturation of lupin seed.

76MT4, Chick pea response to plant density.

76MT5, Effect of waterlogging on lupin species.

76NA9, Polyculture of wheat and lupin.

76NA10, Pasture establishment under cover crops.

76TS12, L cosentinii cv agronomy.

Laboratory Simulation Of Rainfall Erosivity For Gully Formation Study, T. Y. Kao

KWRRI Research Reports

The objective of this study was to develop a rainfall simulator, which imparts to the laboratory rainfall the more important characteristics of natural rainfall such as intensity, drop spectrum, kinetic energy, and momentum at impact, for using in soil erosion research with better results. In developing this simulator the better features of the basic types of earlier simulators, drip and nozzle, have been incorporated into this single design. The simulator developed in this study consists of a number of individual box modules placed in a rectangular pattern to form a single unit. Each module has a grid of capillary holes …

Protection Of Our Fragile Upper Atmosphere, Clayton Clark

Faculty Honor Lectures

Termination of U.S. government support for the Supersonic Transport, SST, may eventually cost the United States its leadership in aviation and billions of dollars in international trade losses, yet if the world wide SST program is allowed to continue, the costs to mankind as a result of damage to environmental resources could be much higher. The decision to terminate the project was heavily based upon concern for possible changes in the properties of the upper atmosphere as a result of SST operations in that realm, with consequent danger to plant and animal life on the Earth below. Briefly, the concern …