Other Environmental Sciences Commons^™

The Effectiveness Of The Asos, Mmts, Gill, And Crs Air Temperature Radiation Shields*, K. G. Hubbard, X. Lin, E.A. Walter-Shea

School of Natural Resources: Faculty Publications

Periodic upgrades of air temperature measurement systems in surface weather station networks cause data discontinuities. From a climatological viewpoint, it is necessary to evaluate the air temperature data discontinuities when air temperature radiation shields are upgraded. This study was undertaken to investigate the effectiveness of four common air temperature radiation shields including the Automated Surface Observing System (ASOS), the Maximum–Minimum Temperature System (MMTS), the Gill, and the Cotton Region Shelter (CRS) shields. The solar radiation shielding effectiveness for each shield under typical grass ground surface and different artificial surfaces (black, white, and aluminum) were investigated. The shield effectiveness was evaluated …

Evaluation And Assessment Of Agrichemical Contaminants In The Creighton, Ne Area, Mark E. Burbach, Roy F. Spalding

School of Natural Resources: Faculty Publications

The Lewis and Clark Natural Resources District (LCNRD) has reported elevated nitrate- nitrogen (NO3-N) concentrations in ground water near Creighton, NE. The U.S. Environmental Protection Agency has set a maximum contaminant level (MCL) of 10 mg/L for NO3-N in public water supplies. NO3-N in the city of Creighton municipal drinking water wells and several rural domestic and irrigation wells have exceeded the MCL. The city of Creighton has constructed a reverse-osmosis water treatment system at a cost of $1.1 million to reduce the NO3-N concentration below the MCL in its water supply. In response to this NO3-N contamination problem the …

Airflow Characteristics Of Commonly Used Temperature Radiation Shields*, X. Lin, Kenneth G. Hubbard, George E. Meyer

School of Natural Resources: Faculty Publications

The air temperature radiation shield is a key component in air temperature measurement in weather station networks; however, it is widely recognized that significant errors in the measured air temperature exist due to insufficient airflow past the air temperature sensor housed inside the shield. During the last several decades, the U.S. National Weather Service has employed a number of different shields in air temperature measurements. This paper focuses on the airflow characteristics inside air temperature shields including the Maximum–Minimum Temperature System (MMTS), the Gill shields, and the Cotton Region Shelter (CRS).

Average airspeed profiles and airflow efficiency inside the shields …

Forestry's Role In Sustainable Agriculture, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Determination Of Drag Properties Of A Shelterbelt From Measurements And A Numerical Model, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Pressure Perturbations Around Shelterbelts: Measurements And Model Results, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Windbreaks An Old System With A New Look, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Windbreaks: Are They Effective?, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Silvopastoral Systems In The Pine Ridge Of Nebraska, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Windbreak Practices, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Oxygen Budget For Lake Ogallala, Kyle D. Hoagland, John C. Holz, Tadd M. Barrow, Richard J. Ruane

School of Natural Resources: Faculty Publications

Lake Ogallala, located below Kingsley Dam which impounds Lake McConaughy in Keith County, Nebraska, is a 260-surface hectare lake with an average depth of approximately eight meters. The lake provides mUltiple uses including a sport fishery and a hydropower and irrigation regulation basin. Since the installation of the hydroelectric generating plant in 1984 (Kingsley Dam was constructed in 1942) and the continued eutrophication of Lake McConaughy, dissolved oxygen concentrations have generally declined in Lake Ogallala. Hypolimnetic withdrawal from Lake McConaughy results in depressed oxygen levels in Lake Ogallala during the mid to latter part of the summer, particularly in certain …

Late Albian Kiowa-Skull Creek Marine Transgression, Lower Dakota Formation, Eastern Margin Of Western Interior Seaway, R.L. Brenner, G.A. Ludvigson, B.J. Witzke, A.N. Zawistoski, E.P. Kvale, R.L. Ravn, R.M. Joeckel

School of Natural Resources: Faculty Publications

No abstract provided.

Breeding Season Demography And Movements Of Eastern Towhees At The Savannah River Site, South Carolina, David G. Krementz, Larkin A. Powell

School of Natural Resources: Faculty Publications

The Eastern Towhee (Pipilo erythrophthalmus) has undergone population declines across much of its range, especially in New England. Despite being a widespread and, at one time, a common species, relatively little is known about its natural history, ecology, or demographics. We conducted baseline research on Eastern Towhees at the Savannah River Site, South Carolina, in 1995 and 1996 to estimate breeding season survival rates, nest success rates, breeding densities, and daily movements. We also were interested in whether towhees had differences in survival and movement rates between young and mature managed pine stands. We found that survival rates during the …

The Effect Of Structure On The Drag Force Of A Windbreak, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Earth In Four Dimensions: Development Of The Ideas Of Geologic Time And History, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Changes in ideas and in technology can come about as slow incremental modifications, as well as by major paradigm shifts. In the case of the development of the ideas of geologic history and time, I will try to present these changes broadly and then look at how some of these have affected interpretation of Nebraska geology. Changes of view on three fronts were important in the development of geologic history and time concepts. First is the question of the nature of time. Is time cyclic or is it linear? The Greco-Oriental cultures had a world view based on cosmic cycles, …

Notes And Correspondence: The Effects Of Data Gaps On The Calculated Monthly Mean Maximum And Minimum Temperatures In The Continental United States: A Spatial And Temporal Study, David E. Stooksbury, Craig D. Idso, Kenneth G. Hubbard

School of Natural Resources: Faculty Publications

Gaps in otherwise regularly scheduled observations are often referred to as missing data. This paper explores the spatial and temporal impacts that data gaps in the recorded daily maximum and minimum temperatures have on the calculated monthly mean maximum and minimum temperatures. For this analysis 138 climate stations from the United States Historical Climatology Network Daily Temperature and Precipitation Data set were selected. The selected stations had no missing maximum or minimum temperature values during the period 1951–80. The monthly mean maximum and minimum temperatures were calculated for each station for each month. For each month 1–10 consecutive days of …

Filter Strip Performance And Processes For Different Vegetation, Widths, And Contaminants, T. J. Schmitt, M. G. Dosskey, K. D. Hoagland

School of Natural Resources: Faculty Publications

Filter strips are widely prescribed to reduce contaminants in surface runoff from agricultural fields. Tbis study compared performance of different filter strip designs on several contaminants and evaluated the contribnting processes. Different vegetation types and widths were investigated using simulated runoff event on large plots (3 m X 7.5 or 15 m) having fine-textured soil and a 6 to 7% slope. Filter strips 7.5 and 15 m wide downslope greatly reduced concentrations of sediment in runoff (76-93%) and contaminants strongly associated with sediment (total P, 55-79%; permethrin, 27-83% [(3-phenoxyphenyl) methyl (±)-cis, trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxylate ]). They had less effect on concentrations …

An Objective Method For Determining Principal Time Scales Of Coherent Eddy Structures Using Orthonormal Wavelets, Jozsef Szilagyi, Marc B. Parlange, Gabriel G. Katul, John D. Albertson

School of Natural Resources: Faculty Publications

No abstract provided.

Streamflow Depletion Investigations In The Republican River Basin: Colorado, Nebraska, And Kansas, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

A Revised Measurement Methodology For Conifer Needles Spectral Optical Properties: Evaluating The Influence Of Gaps Between Elements, Mark A. Mesarch, Elizabeth Walter-Shea, Gregory P. Asner, Elizabeth M. Middleton, Stephen Chan

School of Natural Resources: Faculty Publications

Gaps are unavoidable when compositing small or narrow plant parts (e.g., conifer needles, twigs, narrow leaves, and leaflets) on sample holders in preparation for measuring spectral optical properties. The Daughtry et al. (1989) (A new technique to measure the spectral properties of conifer needles. Remote Sens. Environ. 27:81-91.) method of measuring conifer needle optical properties utilizes a relatively large gap fraction (approximately 0.3-0.6) and needles painted black on one surface of the sample from which the gap fraction of the sample is indirectly determined. Following this protocol typically results in distortions in optical properties, including underestimates in transmittance (sometimes negative …

The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski

School of Natural Resources: Faculty Publications

Habitat fragmentation has been implicated as a major cause of population decline in grassland birds. We tested the hypothesis that a combination of area and shape determines the use of grassland patches by breeding birds. We compared both species richness and individual species presence in 45 wet meadow grasslands in the floodplain of the central Platte River, Nebraska. Bird data were collected through the use of belt transects and supplemented by walking and listening outside transects. Our data supported our primary hypothesis that perimeter–area ratio, which reflects both the area and shape of a patch, is the strongest predictor of …

The Nebraska Earth Science Education Network Electronic Communication Project, D. C. Gosselin, R. Feurer, S. Frack, A. Musson, L. Mayo, C. Karel, E. Schaefer, C. Snyder, J. Sarchett, M. L. Alfieri

School of Natural Resources: Faculty Publications

No abstract provided.

A Geomorphology-Based Semi-Distributed Watershed Model, J. Szilagyi, M. B. Parlange

School of Natural Resources: Faculty Publications

No abstract provided.

Relationship Between Ecosystem Productivity And Photosynthetically Active Radiation For Northern Peatlands, S. E. Frolkin, J.L. Bubier, T.R. Moore, T. Ball, L.M. Bellisario, A. Bhardwaj, P. Carroll, P.M. Crill, Peter M. Lafleur, J.H. Mccaughey, N.T. Roulet, A. E. Suyker, S.B. Verma, J.M. Waddington, G.J. Whiting

School of Natural Resources: Faculty Publications

We analyzed the relationship between new ecosystem exchange of carbon dioxide (NEE) and irradiance (as photosynthetic photon flux density of PPFD), using published and unpublished data that have been collected during midgrowing season for carbon balance studies at seven peatlands in North America and Europe. NEE measurements included both eddy-correlation tower and clear, static chamber methods, which gave very similar results. Data were analyzed by site, as aggregated data set for all peatland type (bog, poor fen, rich fen, and all fens) and as a single aggregated data set for all peatlands. In all cases, a fit with a rectangular …

Air Temperature Variations And Rice Productivity In Bangladesh: A Comparative Study Of The Performance Of The Yield And The Ceres-Rice Models, Rezaul Mahmood

School of Natural Resources: Faculty Publications

Potential increase in air temperature due to climatic change and inter-annual climatic variability and its impacts on crop productivity is of major concern to crop scientists. A number of physically-based models have been developed and applied to estimate crop–environment relationships. In the present study the performance of two such models (the YIELD and the CERES-Rice) are discussed. These two models are used to estimate boro rice productivity under normal and abnormal climate scenarios in Bangladesh. This study finds that boro rice productivity at Mymensingh predicted by the YIELD is higher than the prediction by the CERES-Rice. Productivity estimates for Barisal …

Climatology Of The Daily Temperature Range Annual Cycle In The United States, Daniel J. Leathers, Michael A. Palecki, David A. Robinson, Kenneth F. Dewey

School of Natural Resources: Faculty Publications

Many researchers are presently interested in detecting long-term trends in annual or seasonal daily temperature range (DTR), and attributing these changes to anthropogenic origins. However, very little work has been done to confirm the mechanisms that are important to determining the long-term average annual cycle of the DTR. Therefore, the focus of this work is to examine the spatial and temporal difference in the DTR average annual cycle across the United States, and to associate the patterns of these cycles with potential causal variables. Three major types of DTR annual cycle exist in the United States: high sun season maximum …

Optical Properties Of Canopy Elements In Black Spruce, Jack Pine And Aspen Stands In Saskatchewan, Canada, Elizabeth A. Walter-Shea, Mark A. Mesarch

School of Natural Resources: Faculty Publications

No abstract provided.

Unique Frontal Sinuses In Fossil And Living Hyaenidae (Mammalia, Carnivora): Description And Interpretation, R.M. Joeckel

School of Natural Resources: Faculty Publications

No abstract provided.

Impacts Of Air Temperature Variations On The Boro Rice Phenology In Bangladesh: Implications For Irrigation Requirements, Rezaul Mahmood

School of Natural Resources: Faculty Publications

Air temperature significantly affects crop phenology. Numerous experiments have shown that prevailing air temperature determines the length of crop growth stages. Irrigation field requirements depend on the length of the crop growth stages. In the present study, a physically based parametric model, YIELD, has been applied to estimate the impacts of fluctuating air temperature (due to inter-annual climatic variability and global warming) on evapotranspiration water requirements and the length of growth stages of the irrigated boro rice in Bangladesh. The YIELD model is crop specific and crop-growth-stage specific which is a compromise between area-specific regression models and complex crop growth …

Spectral Information Content Of The Boreal Forest, Elizabeth A. Walter-Shea

School of Natural Resources: Faculty Publications

No abstract provided.