scholarly journals The Effects of Snow Cover on Midlatitude Cyclones in the Great Plains

2005 ◽  
Vol 6 (3) ◽  
pp. 263-279 ◽  
Author(s):  
N. Elguindi ◽  
B. Hanson ◽  
D. Leathers
Keyword(s):  
Snow Cover ◽  
Great Plains ◽  
Mesoscale Model ◽  
The United States ◽  
Lower Atmosphere ◽  
Northern Great Plains ◽  
State University ◽  
Moisture Advection ◽  
Penn State ◽  
Midlatitude Cyclones

Abstract The impacts of snow cover on the structure and intensity of midlatitude cyclones are examined. The fifth-generation Pennsylvania State University–National Center for Atmospheric Research (Penn State–NCAR) Mesoscale Model (MM5) was used to simulate eight synoptic events in which a well-developed cyclone moved across the central and northern Great Plains region of the United States. Two simulations were performed for each event: a control run with the actual snow cover and a perturbed run with an extensive snow cover. In all of the cases, increasing the snow cover, and thereby reducing the available potential energy, weakened the cyclones. Among the eight cases, the averaged minimum central low pressure of the cyclones in the perturbed runs was approximately 4 mb greater than the control cyclones. The reduction in temperature and moisture in the lower atmosphere was most pronounced in the warm sector, which significantly reduced the thermal and moisture gradients near the surface. This resulted in a weakening of the fronts, less convergence near the surface, and decreased precipitation. Averaged among the cases, the upward vertical velocity near the center of the low was about 3.5 cm s−1 less in the perturbed simulations. Accumulated vertically integrated rainwater was reduced by 0.64 × 109 m3 when averaged for all of the cases in the perturbed simulations. In addition, the weaker gradients across the surface fronts in the increased snow-covered simulations decreased thermal and moisture advection near the surface and may have contributed to limiting the cyclones’ intensification in some of the cases by dampening positive feedback processes between the surface and midtroposphere.

scholarly journals A Teleconnection between Forced Great Plains Snow Cover and European Winter Climate

2008 ◽  
Vol 21 (11) ◽  
pp. 2466-2483 ◽  
Author(s):  
Nicholas P. Klingaman ◽  
Brian Hanson ◽  
Daniel J. Leathers
Keyword(s):  
Snow Cover ◽  
Great Plains ◽  
North American ◽  
The United States ◽  
Northern Great Plains ◽  
Late Winter ◽  
Winter Climate ◽  
Early Season ◽  
Late Season ◽  
The North

Abstract Anomalies in Siberian snow cover have been shown to affect Eurasian winter climate through the North Atlantic Oscillation (NAO). The existence of a teleconnection between North American snow cover and the NAO is far less certain, particularly for limited, regional snow cover anomalies. Using three ensembles of the Community Atmosphere Model, version 2 (CAM2), the authors examined teleconnections between persistent, forced snow cover in the northern Great Plains of the United States and western Eurasian winters. One ensemble allowed the model to freely determine global snow cover, while the other two forced a 72-cm snowpack centered over Nebraska. Of the forced ensembles, the “early-season” (“late season”) simulations initiated the snowpack on 1 November (1 January). The additional snow cover generated lower (higher) sea level pressures and geopotential heights over Iceland (the Azores) and warmer (cooler) temperatures over northern and western (eastern and southeastern) Europe, which suggests the positive NAO phase. Differences between the free-snow-cover and early-season ensembles were never significant until January, which implied either that the atmospheric response required a long lag or that the late-winter atmosphere was particularly sensitive to Great Plains snow. The authors rejected the former hypothesis and supported the latter by noting similarities between the early- and late-season ensembles in late winter for European 2-m temperatures, transatlantic circulation, and an NAO index. Therefore, a regional North American snow cover anomaly in an area of high inter- and intra-annual snow cover variability can show a stronger teleconnection to European winter climate than previously reported for broader snow cover anomalies. In particular, anomalous late-season snow in the Great Plains may shift the NAO toward the positive phase.

VARIATION IN PATHOGENICITY BETWEEN ISOLATES OF CLAVICEPS PURPUREA

1977 ◽  
Vol 57 (3) ◽  
pp. 729-733 ◽  
Author(s):  
L. C. DARLINGTON ◽  
D. E. MATHRE ◽  
R. H. JOHNSTON
Keyword(s):  
Great Plains ◽  
Triticum Aestivum L ◽  
The United States ◽  
Northern Great Plains ◽  
Claviceps Purpurea ◽  
Male Sterile ◽  
Hordeum Vulgare L ◽  
Clear Cut ◽  
Weakly Virulent ◽  
Grass Hosts

Isolates of Claviceps purpurea (Fr.) Tul. originally isolated from many different grass hosts in the northern Great Plains and several other areas in the United States and England were tested for their pathogenicity to selected cultivars or lines of male-sterile wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). While there was a great range in the level of virulence, no clear-cut evidence of specific races was obtained. A few isolates were weakly virulent on two cultivars of male-sterile spring wheat but were highly virulent on the other two cultivars tested. Wheat and barley breeders are advised to use a mixture of isolates in screening germ plasm for resistance to ergot.

Rearing the wheat stem sawfly on an artificial diet

2005 ◽  
Vol 137 (4) ◽  
pp. 497-500 ◽  
Author(s):  
Tuilo B. Macedo ◽  
Paula A. Macedo ◽  
Robert K.D. Peterson ◽  
David K. Weaver ◽  
Wendell L. Morrill
Keyword(s):  
Great Plains ◽  
Cropping Systems ◽  
Insect Pest ◽  
The United States ◽  
Northern Great Plains ◽  
Yield Losses ◽  
Canadian Prairies ◽  
Wheat Stem Sawfly ◽  
Head Weight ◽  
Harvest Efficiency

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is an insect pest in dryland wheat cropping systems in the southern Canadian Prairies and the northern Great Plains of the United States (Morrill 1997). Yield losses caused by C. cinctus are due to reduced head weight (Holmes 1977; Morrill et al. 1992) and lodging, which decreases harvest efficiency. Estimates of yield losses in Montana alone are about US$25 million per year.

scholarly journals Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2013

Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Winter Wheat ◽  
Leaf Rust ◽  
Great Plains ◽  
Puccinia Triticina ◽  
The United States ◽  
Northern Great Plains ◽  
Ohio River ◽  
Ohio Valley ◽  
Red Winter Wheat

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.

scholarly journals Phytoplankton productivity across prairie saline lakes of the Great Plains (USA): a step toward deciphering patterns through lake classification models

2009 ◽  
Vol 66 (9) ◽  
pp. 1435-1448 ◽  
Author(s):  
Courtney R. Salm ◽  
Jasmine E. Saros ◽  
Sherilyn C. Fritz ◽  
Christopher L. Osburn ◽  
David M. Reineke
Keyword(s):  
Primary Production ◽  
Nutrient Limitation ◽  
Great Plains ◽  
Saline Lakes ◽  
Information Criterion ◽  
The United States ◽  
Northern Great Plains ◽  
Classification Models ◽  
Phytoplankton Productivity ◽  
P Limitation

We investigated patterns of primary production across prairie saline lakes in the central and northern Great Plains of the United States. Based on comparative lake sampling in 2004, seasonal predictors of algal primary productivity were identified within subsets of similar lakes using a combination of Akaike’s information criterion (AIC) and classification and regression trees (CART). These models indicated complex patterns of nutrient limitation by nitrogen (N), phosphorus (P), and iron (Fe) within different lake groups. Nutrient enrichment assays (control, + Fe, + N, + P, + N + P) were performed in spring and summer of 2006 to determine if phytoplankton in selected lakes followed predicted patterns of nutrient limitation. Both the comparative lake sampling and experimental results indicated that N limitation was widespread in these prairie lakes, with evidence for secondary P limitation in certain lakes. In the experiments, iron did not stimulate primary production. Our results suggest that given the diverse geochemical nature of these lakes, classification models that separate saline lakes into subsets may be an effective method for improving predictions of algal production.

scholarly journals International design collaboration and mentoring for tertiary students through Facebook

2012 ◽  
Vol 28 (5) ◽  
Author(s):  
Josh McCarthy
Keyword(s):  
United States ◽  
Digital Media ◽  
Undergraduate Students ◽  
The United States ◽  
State University ◽  
Postgraduate Students ◽  
Student Cohorts ◽  
Penn State ◽  
The University ◽  
Industry Professionals

<span>This study explores the efficacy of the online social networking site </span><em>Facebook</em><span>, for linking international digital media student cohorts through an e-mentoring scheme. It reports on the 2011 collaboration between the University of Adelaide in Australia, and Penn State University in the United States. Over one semester, twelve postgraduate students in Australia and ten undergraduate students in the United States took part in an online mentor scheme hosted by </span><em>Facebook</em><span>. Students were required to submit work-in-progress imagery each week to a series of galleries within the forum. Postgraduate students from Adelaide mentored the undergraduate students at Penn State, and in turn, staff and associated industry professionals mentored the Adelaide students. Interaction between the two student cohorts was consistently strong throughout the semester, and all parties benefitted from the collaboration. Students from Penn State University were able to receive guidance and critiques from more experienced peers, and responded positively to the continual feedback over the semester. Students from the University of Adelaide received support from three different groups: Penn State staff and associated professionals; local industry professionals and recent graduates; and peers from Penn State. The 2011 scheme highlighted the efficacy of </span><em>Facebook</em><span> as a host site for e-mentoring and strengthened the bond between the two collaborating institutions.</span>

scholarly journals Regional uptake and release of crop carbon in the United States

2011 ◽  
Vol 8 (8) ◽  
pp. 2037-2046 ◽  
Author(s):  
T. O. West ◽  
V. Bandaru ◽  
C. C. Brandt ◽  
A. E. Schuh ◽  
S. M. Ogle
Keyword(s):  
Great Plains ◽  
Carbon Budget ◽  
Supply And Demand ◽  
The United States ◽  
Northern Great Plains ◽  
Agricultural Crops ◽  
Biomass Storage ◽  
The Us ◽  
Import And Export ◽  
Crop Biomass

Abstract. Carbon fixed by agricultural crops in the US creates regional CO2 sinks where it is harvested and regional CO2 sources where it is released back to the atmosphere. The quantity and location of these fluxes differ depending on the annual supply and demand of crop commodities. Data on the harvest of crop biomass, storage, import and export, and on the use of biomass for food, feed, fiber, and fuel were compiled to estimate an annual crop carbon budget for 2000 to 2008. With respect to US Farm Resource Regions, net sources of CO2 associated with the consumption of crop commodities occurred in the Eastern Uplands, Southern Seaboard, and Fruitful Rim regions. Net sinks associated with the production of crop commodities occurred in the Heartland, Northern Great Plains, and Mississippi Portal regions. The national crop carbon budget was balanced to within 0.3 to 6.1 % yr−1 during the period of this analysis.

scholarly journals A Unified Effort to Fight an Enemy of Wheat and Barley: Fusarium Head Blight

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1712-1728 ◽  
Author(s):  
Marcia McMullen ◽  
Gary Bergstrom ◽  
Erick De Wolf ◽  
Ruth Dill-Macky ◽  
Don Hershman ◽  
...  
Keyword(s):  
United States ◽  
Fusarium Head Blight ◽  
Great Plains ◽  
Plant Disease ◽  
Management Strategies ◽  
The United States ◽  
Export Market ◽  
Northern Great Plains ◽  
Head Blight ◽  
Food And Feed

Wheat and barley are critical food and feed crops around the world. Wheat is grown on more land area worldwide than any other crop. In the United States, production of wheat and barley contributes to domestic food and feed use, and contributes to the export market and balance of trade. Fifteen years ago, Plant Disease published a feature article titled “Scab of wheat and barley: A re-emerging disease of devastating impact”. That article described the series of severe Fusarium head blight (FHB) epidemics that occurred in the United States and Canada, primarily from 1991 through 1996, with emphasis on the unparalleled economic and sociological impacts caused by the 1993 FHB epidemic in spring grains in the Northern Great Plains region. Earlier publications had dealt with the scope and damage caused by this disease in the United States, Canada, Europe, and China. Reviews published after 1997 further described this disease and its impact on North American grain production in the 1990s. This article reviews the disease and documents the information on U.S. FHB epidemics since 1997. The primary goal of this article is to summarize a sustained, coordinated, and collaborative research program that was put in place shortly after the 1993 epidemic, a program intended to quickly lead to improved management strategies and outreach implementation. This program serves as a model to deal with other emerging plant disease threats.

scholarly journals Primary Atmospheric Drivers of Pluvial Years in the United States Great Plains

2018 ◽  
Vol 19 (4) ◽  
pp. 643-658 ◽  
Author(s):  
Paul X. Flanagan ◽  
Jeffrey B. Basara ◽  
Jason C. Furtado ◽  
Xiangming Xiao
Keyword(s):  
United States ◽  
Great Plains ◽  
Heavy Precipitation ◽  
The United States ◽  
Precipitation Variability ◽  
Northern Great Plains ◽  
Southern Great Plains ◽  
The Public ◽  
Moisture Fluxes ◽  
Precipitation Events

Abstract Precipitation variability has increased in recent decades across the Great Plains (GP) of the United States. Drought and its associated drivers have been studied in the GP region; however, periods of excessive precipitation (pluvials) at seasonal to interannual scales have received less attention. This study narrows this knowledge gap with the overall goal of understanding GP precipitation variability during pluvial periods. Through composites of relevant atmospheric variables from the ECMWF twentieth-century reanalysis (ERA-20C), key differences between southern Great Plains (SGP) and northern Great Plains (NGP) pluvial periods are highlighted. The SGP pluvial pattern shows an area of negative height anomalies over the southwestern United States with wind anomalies consistent with frequent synoptic wave passages along a southward-shifted North Pacific jet. The NGP pattern during pluvial periods, by contrast, depicts anomalously low heights in the northwestern United States and an anomalously extended Pacific jet. Analysis of daily heavy precipitation events reveals the key drivers for these pluvial events, namely, an east–west height gradient and associated stronger poleward moisture fluxes. Therefore, the results show that pluvial years over the GP are likely driven by synoptic-scale processes rather than by anomalous seasonal precipitation driven by longer time-scale features. Overall, the results present a possible pathway to predicting the occurrence of pluvial years over the GP and understanding the causes of GP precipitation variability, potentially mitigating the threats of water scarcity and excesses for the public and agricultural sectors.

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