scholarly journals Warm Season Mesoscale Superensemble Precipitation Forecasts in the Southeastern United States

2007 ◽  
Vol 22 (4) ◽  
pp. 873-886 ◽  
Author(s):  
T. J. Cartwright ◽  
T. N. Krishnamurti
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Warm Season ◽  
Stage Iv ◽  
Time Of Day ◽  
Florida State University ◽  
State University ◽  
Synoptic Conditions ◽  
Subtropical Highs ◽  
Operational Models

Abstract With current computational limitations, the accuracy of high-resolution precipitation forecasts has limited temporal and spatial resolutions. However, with the recent development of the superensemble technique, the potential to improve precipitation forecasts at the regional resolution exists. The purpose of this study is to apply the superensemble technique to regional precipitation forecasts to generate more accurate forecasts pinpointing exact locations and intensities of strong precipitation systems. This study will determine the skill of a regional superensemble forecast out to 60 h by examining its equitable threat score and its false alarm ratio. The regional superensemble consists of 12–60-h daily quantitative precipitation forecasts from six models. Five are independent operational models, and one comes from the physically initialized Florida State University regional spectral model. The superensemble forecasts are verified during the summer 2003 season over the southeastern United States using merged River Forecast Center stage-IV radar–gauge and satellite analyses. Precipitation forecasts were skillful in outperforming the operational models at all model times. Precipitation results were stratified by time of day to allow detections of the diurnal cycle. As expected, warm season daytime precipitation is commonly forced by convection, which is difficult to accurately model. Major synoptic regimes, including subtropical highs, midlatitude troughs/fronts, and tropical cyclones, were examined to determine the skill of the superensemble under various synoptic conditions.

scholarly journals Climatology and Environmental Characteristics of Extreme Precipitation Events in the Southeastern United States

2015 ◽  
Vol 143 (3) ◽  
pp. 718-741 ◽  
Author(s):  
Benjamin J. Moore ◽  
Kelly M. Mahoney ◽  
Ellen M. Sukovich ◽  
Robert Cifelli ◽  
Thomas M. Hamill
Keyword(s):  
United States ◽  
Extreme Precipitation ◽  
Southeastern United States ◽  
Warm Season ◽  
Stage Iv ◽  
Flow Patterns ◽  
Water Vapor Transport ◽  
Cool Season ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract This paper documents the characteristics of extreme precipitation events (EPEs) in the southeastern United States (SEUS) during 2002–11. The EPEs are identified by applying an object-based method to 24-h precipitation analyses from the NCEP stage-IV dataset. It is found that EPEs affected the SEUS in all months and occurred most frequently in the western portion of the SEUS during the cool season and in the eastern portion during the warm season. The EPEs associated with tropical cyclones, although less common, tended to be larger in size, more intense, and longer lived than “nontropical” EPEs. Nontropical EPEs in the warm season, relative to those in the cool season, tended to be smaller in size and typically involved more moist, conditionally unstable conditions but weaker dynamical influences. Synoptic-scale composites are constructed for nontropical EPEs stratified by the magnitude of vertically integrated water vapor transport (IVT) to examine distinct scenarios for the occurrence of EPEs. The composite results indicate that “strong IVT” EPEs occur within high-amplitude flow patterns involving strong transport of moist, conditionally unstable air within the warm sector of a cyclone, whereas “weak IVT” EPEs occur within low-amplitude flow patterns featuring weak transport but very moist and conditionally unstable conditions. Finally, verification of deterministic precipitation forecasts from a reforecast dataset based on the NCEP Global Ensemble Forecast System reveals that weak-IVT EPEs were characteristically associated with lower forecast skill than strong-IVT EPEs. Based on these results, it is suggested that further research should be conducted to investigate the forecast challenges associated with EPEs in the SEUS.

scholarly journals Seasonal Hydrological Forecasts for Watersheds over the Southeastern United States for the Boreal Summer and Fall Seasons

2013 ◽  
Vol 17 (25) ◽  
pp. 1-22 ◽  
Author(s):  
Satish Bastola ◽  
Vasubandhu Misra ◽  
Haiqin Li
Keyword(s):  
United States ◽  
South Carolina ◽  
Climate Model ◽  
Southeastern United States ◽  
Boreal Summer ◽  
Hydrological Models ◽  
State University ◽  
Streamflow Prediction ◽  
Seasonal Climate ◽  
Hydrological Prediction

Abstract The authors evaluate the skill of a suite of seasonal hydrological prediction experiments over 28 watersheds throughout the southeastern United States (SEUS), including Florida, Georgia, Alabama, South Carolina, and North Carolina. The seasonal climate retrospective forecasts [the Florida Climate Institute–Florida State University Seasonal Hindcasts at 50-km resolution (FISH50)] is initialized in June and integrated through November of each year from 1982 through 2001. Each seasonal climate forecast has six ensemble members. An earlier study showed that FISH50 represents state-of-the-art seasonal climate prediction skill for the summer and fall seasons, especially in the subtropical and higher latitudes. The retrospective prediction of streamflow is based on multiple calibrated rainfall–runoff models. The hydrological models are forced with rainfall from FISH50, (quantile based) bias-corrected FISH50 rainfall (FISH50_BC), and resampled historical rainfall observations based on matching observed analogs of forecasted quartile seasonal rainfall anomalies (FISH50_Resamp). The results show that direct use of output from the climate model (FISH50) results in huge biases in predicted streamflow, which is significantly reduced with bias correction (FISH50_BC) or by FISH50_Resamp. On a discouraging note, the authors find that the deterministic skill of retrospective streamflow prediction as measured by the normalized root-mean-square error is poor compared to the climatological forecast irrespective of how FISH50 (e.g., FISH50_BC, FISH50_Resamp) is used to force the hydrological models. However, our analysis of probabilistic skill from the same suite of retrospective prediction experiments reveals that, over the majority of the 28 watersheds in the SEUS, significantly higher probabilistic skill than climatological forecast of streamflow can be harvested for the wet/dry seasonal anomalies (i.e., extreme quartiles) using FISH50_Resamp as the forcing. The authors contend that, given the nature of the relatively low climate predictability over the SEUS, high deterministic hydrological prediction skills will be elusive. Therefore, probabilistic hydrological prediction for the SEUS watersheds is very appealing, especially with the current capability of generating a comparatively huge ensemble of seasonal hydrological predictions for each watershed and for each season, which offers a robust estimate of associated forecast uncertainty.

Curvularia malina sp. nov. incites a new disease of warm-season turfgrasses in the southeastern United States

Mycologia ◽  
2016 ◽  
Vol 108 (5) ◽  
pp. 915-924 ◽  
Author(s):  
Maria Tomaso-Peterson ◽  
Young-Ki Jo ◽  
Phillip L. Vines ◽  
Federico G. Hoffmann
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Warm Season ◽  
New Disease

scholarly journals Study Paths, Riemann Surfaces And Strebel Differentials

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
Peter Buser ◽  
Klaus-Dieter Semmler
Keyword(s):  
United States ◽  
School System ◽  
Riemann Surfaces ◽  
Conformal Geometry ◽  
The United States ◽  
Florida State University ◽  
State University ◽  
Surface Theory ◽  
The University ◽  
Study Behaviour

These pages aim to explain and interpret why the late Mika Seppälä, a conformal geometer, proposed to model student study behaviour using concepts from conformal geometry, such as Riemann surfaces and Strebel differentials. Over many years Mika Seppälä taught online calculus courses to students at Florida State University in the United States, as well as students at the University of Helsinki in Finland. Based on the click log data of his students in both populations, he monitored this course using edge-decorated graphs, which he gradually improved over the years. To enhance this representation even further, he suggested using tools and geometric intuition from Riemann surface theory. He also was inspired by the much-envied Finnish school system. Bringing these two sources of inspiration together resulted in a promising new representation model for course monitoring. Even though the authors have not been directly involved in Mika Seppälä’s courses, being conformal geometers themselves, they attempt to shed some light on his proposed approach.

scholarly journals Winter grazing stockpiled native warm‐season grasses in the Southeastern United States

2018 ◽  
Author(s):  
Neal R. Wepking ◽  
Renata L. G. Nave ◽  
J. Travis Mulliniks ◽  
Zachary D. McFarlane
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Warm Season ◽  
Winter Grazing ◽  
Warm Season Grasses

Diagnosis of Trichodorus obtusus and Paratrichodorus minor on Turfgrasses in the Southeastern United States

2005 ◽  
Vol 6 (1) ◽  
pp. 20 ◽  
Author(s):  
William T. Crow
Keyword(s):  
United States ◽  
Plant Pathogens ◽  
Southeastern United States ◽  
Warm Season ◽  
Plant Viruses ◽  
Stubby Root Nematode

“Stubby-root” nematodes are of agricultural importance as plant-pathogens and as vectors for plant viruses. Two species of stubby-root nematode have been identified as pathogens on warm-season turfgrasses in the southern U.S.: Paratrichodorus minor and Trichodorus obtusus. Both are pathogens of bermudagrass and St. Augustinegrass, with T. obtusus more damaging than P. minor. Methods for distinguishing these species are described that do not require mounting of specimens and can be used at ×100 magnification or less. Accepted for publication 24 November 2004. Published 21 January 2005.

Tolerance of pintoi peanut to PRE and POST herbicides

2020 ◽  
Vol 34 (6) ◽  
pp. 870-875
Author(s):  
Logan J. Martin ◽  
José Luiz C.S. Dias ◽  
Brent A. Sellers ◽  
Jason A. Ferrell ◽  
Ramon G. Leon ◽  
...  
Keyword(s):  
United States ◽  
Weed Management ◽  
Southeastern United States ◽  
Warm Season ◽  
Future Research ◽  
Herbicide Application ◽  
Forage Crop ◽  
Herbicide Treatments ◽  
Perennial Legume ◽  
Significant Injury

AbstractPintoi peanut is a warm-season perennial legume that shows promise as a forage crop for the southeastern United States, however, little is known about the proper methods of weed management during establishment for this species. The objective of this study was to determine the ability of pintoi peanut to tolerate applications of PRE and POST herbicides during the year of and year after planting. The effects of herbicide treatments on percentage of visual estimates of injury and stand counts of pintoi peanut were investigated at Ona and Marianna, FL, in 2015 and 2016. All PRE herbicides did not result in significant injury or stand reduction. Pintoi peanut’s tolerance to POST herbicides was higher when plants were emerged for at least 2 wk prior to herbicide application. Stands of pintoi peanut that were planted the previous year appear to tolerate all herbicides examined in this work, except sulfosulfuron. Results of this study indicate that at the year of planting pintoi peanut is tolerant to PRE applications of pendimethalin, imazethapyr, and imazapic. Pintoi peanut appears to tolerate applications of 2,4-D, carfentrazone, imazapic and imazethapyr the year after planting at the rates utilized in this study. Future research should evaluate the effects of multiple herbicide applications and tank-mixes to obtain satisfactory weed control and selectivity in pintoi peanut swards.

scholarly journals Frequency and Pathogenicity of Dematiaceous Hyphomycetes on Annual Ryegrass Overseeded on Bermudagrass in Mississippi

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1085-1090 ◽  
Author(s):  
R. G. Pratt
Keyword(s):  
United States ◽  
North American ◽  
Fungal Pathogens ◽  
Cynodon Dactylon ◽  
Southeastern United States ◽  
Axenic Culture ◽  
Warm Season ◽  
Application Site ◽  
Annual Ryegrass ◽  
Dematiaceous Hyphomycetes

Fungal diseases of annual ryegrass (Lolium multiflorum Lam.), a cool-season species grown for forage and turf in the southeastern United States, and bermudagrass (Cynodon dactylon (L.) Pers.), a warm-season perennial, usually are considered distinct. In May 2002 and 2004, symptoms of leaf and stem necrosis were observed simultaneously in forage bermudagrass and overseeded annual ryegrass on a swine waste application site in Mississippi. Sporulation by nine species of Bipolaris, Curvularia, Drechslera, and Exserohilum was observed on symptomatic leaves of ryegrass that were surface disinfested and plated on agar each year, and axenic cultures were established by spore transfers. These isolations represent four new worldwide and two new North American records of occurrence of fungal pathogens on ryegrass, and three new records for the southeastern United States and Mississippi. Bipolaris cynodontis, a common bermudagrass pathogen, and Drechslera dictyoides were observed most frequently on ryegrass during both years. In excised leaves of ryegrass inoculated with infested agar discs, most isolates of B. cynodontis from ryegrass and bermudagrass were equally virulent and caused necrosis equal to or greater than that caused by D. dictyoides, an established ryegrass pathogen. Isolates of B. cynodontis from both hosts also caused similar symptoms in foliage of ryegrass and bermudagrass following spore inoculations. Pathogenicity to ryegrass of five other species of dematiaceous hyphomycetes that represented new worldwide or North American records of occurrence also was demonstrated by foliar inoculations. All pathogens were reisolated from symptomatic tissues and grown in axenic culture for fulfillment of Koch's postulates. Results demonstrate that most of the same species of dematiaceous hyphomycetes infect both forage ryegrass and bermudagrass in Mississippi and indicate that B. cynodontis, in particular, may be a common and virulent pathogen of ryegrass in the southeastern United States.

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