scholarly journals The Daily Cloud-to-Ground Lightning Flash Density in the Contiguous United States and Finland

2011 ◽  
Vol 139 (5) ◽  
pp. 1323-1337 ◽  
Author(s):  
Antti Mäkelä ◽  
Pekka Rossi ◽  
David M. Schultz
Keyword(s):  
United States ◽  
Detection Efficiency ◽  
Quantitative Measure ◽  
The United States ◽  
Lightning Flash ◽  
Upper Midwest ◽  
Lightning Detection ◽  
Operational Forecasting ◽  
Central United States ◽  
Cloud To Ground Lightning

A method is developed to quantify thunderstorm intensity according to cloud-to-ground lightning flashes (hereafter ground flashes) determined by a lightning-location sensor network. The method is based on the ground flash density ND per thunderstorm day (ground flashes per square kilometer per thunderstorm day) calculated on 20 km × 20 km fixed squares. Because the square size roughly corresponds to the area covered by a typical thunderstorm, the flash density for one square defines a unit thunderstorm for the purposes of this study. This method is tested with ground flash data obtained from two nationwide lightning-location systems: the National Lightning Detection Network (NLDN) in the contiguous United States and the portion of the Nordic Lightning Information System (NORDLIS) in Finland. The distribution of daily ground flash density ND is computed for all of Finland and four 800 000 km2 regions in the United States (identified as western, central, eastern, and Florida). Although Finland and all four U.S. regions have median values of ND of 0.01–0.03 flashes per square kilometer per thunderstorm day—indicating that most thunderstorms produce relatively few ground flashes regardless of geographical region—the most intense 1% of the storms (as measured by the 99th percentiles of the ND distributions within each region) show much larger differences among regions. For example, the most intense 1% of the ND distributions is 1.3 flashes per square kilometer per thunderstorm day in the central U.S. region, but only 0.2 flashes per square kilometer per thunderstorm day in Finland. The spatial distribution of the most intense 1% of the ND distributions illustrates that the most intense thunderstorm days occur in the central United States and upper Midwest, which differs from the maxima of the average annual flash density NA and the number of thunderstorm days TD, both of which occur in Florida and along the coast of the Gulf of Mexico. This method for using ND to quantify thunderstorm intensity is applicable to any region as long as the detection efficiency of the lightning-location network is high enough or known. This method can also be employed in operational forecasting to provide a quantitative measure of the lightning intensity of thunderstorms relative to climatology.

scholarly journals Diurnal Variations of NLDN-Reported Cloud-to-Ground Lightning in the United States

2014 ◽  
Vol 142 (3) ◽  
pp. 1037-1052 ◽  
Author(s):  
Ronald L. Holle
Keyword(s):  
United States ◽  
The United States ◽  
Maximum Activity ◽  
Lightning Flash ◽  
Diurnal Changes ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
Local Mean ◽  
Composite Maps ◽  
Mean Time

Abstract National maps of cloud-to-ground lightning flash density (in flashes per square kilometer per year) for one or more years have been produced since the National Lightning Detection Network (NLDN) was first deployed across the contiguous United States in 1989. However, no single publication includes maps of cloud-to-ground flash density across the domain and adjacent areas during the entire diurnal cycle. Cloud-to-ground lightning has strong and variable diurnal changes across the United States that should be taken into account for outdoor lightning-vulnerable activities, particularly those involving human safety. For this study, NLDN cloud-to-ground flash data were compiled in 20 km by 20 km grid squares from 2005 to 2012 for the lower 48 states. A unique feature of this study is that maps were prepared to coincide with local time, not time zones. NLDN flashes were assigned to 2-h time periods in 5° longitude bands. Composite maps of the 2-h periods with the most lightning in each grid square were also prepared. The afternoon from 1200 to 1800 local mean time provides two-thirds of the day’s lightning. However, lightning activity starts before noon over western mountains and onshore along the Atlantic and Gulf of Mexico coasts. These areas are where recurring lightning-vulnerable recreation and workplace activities should expect the threat at these times, rather than view them as an anomaly. An additional result of the study is the midday beginning of lightning over the higher terrain of the western states, then the maximum activity moves steadily eastward. These storms pose a threat to late-afternoon and evening recreation. In some Midwest and plains locations, lightning is most frequent after midnight.

scholarly journals Seasonal, Monthly, and Weekly Distributions of NLDN and GLD360 Cloud-to-Ground Lightning

2016 ◽  
Vol 144 (8) ◽  
pp. 2855-2870 ◽  
Author(s):  
Ronald L. Holle ◽  
Kenneth L. Cummins ◽  
William A. Brooks
Keyword(s):  
United States ◽  
New England ◽  
The United States ◽  
Lightning Flash ◽  
Time Space ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
Annual Total ◽  
The Caribbean ◽  
Using Data

Abstract Annual maps of cloud-to-ground lightning flash density have been produced since the deployment of the National Lightning Detection Network (NLDN). However, a comprehensive national summary of seasonal, monthly, and weekly lightning across the contiguous United States has not been developed. Cloud-to-ground lightning is not uniformly distributed in time, space, or frequency. Knowledge of these variations is useful for understanding meteorological processes responsible for lightning occurrence, planning outdoor events, anticipating impacts of lightning on power reliability, and relating to severe weather. To address this gap in documentation of lightning occurrence, the variability on seasonal, monthly, and weekly scales is first addressed with NLDN flash data from 2005 to 2014 for the 48 states and adjacent regions. Flash density and the percentage of each season’s portion of the annual total are compiled. In spring, thunderstorms occur most often over southeastern states. Lightning spreads north and west until by June, most areas have lightning. New England, the northern Rockies, most of Canada, and the Florida Peninsula have a small percentage of lightning outside of summer. Arizona and portions of adjacent states have the highest incidence in July and August. Flash densities reduce in September in most regions. This seasonal, monthly, and weekly overview complements a recent study of diurnal variations of flashes to document when and where lightning occurs over the United States. NLDN seasonal maps indicate a summer lightning dominance in the northern and western United States that extends into Canada using data compiled from GLD360 network observations. GLD360 also extends NLDN seasonal maps and percentages into Mexico, the Caribbean, and offshore regions.

scholarly journals Cloud-to-Ground Lightning Flash Density and Thunderstorm Day Distributions over the Contiguous United States Derived from NLDN Measurements: 1993–2018

2019 ◽  
Vol 148 (1) ◽  
pp. 313-332 ◽  
Author(s):  
Thomas L. Koehler
Keyword(s):  
United States ◽  
The United States ◽  
Horizontal Resolution ◽  
Precipitation Anomaly ◽  
Lightning Flash ◽  
Southern Rocky Mountains ◽  
Weather Observations ◽  
Cloud To Ground Lightning ◽  
The Mean ◽  
Southern Florida

Abstract This study employs cloud-to-ground (CG) lightning flash data from the U.S. National Lightning Detection Network (NLDN) to examine temporal and spatial distributions of lightning flash and thunderstorm day (TD) occurrences over the contiguous United States from 1993 to 2018. TD distributions are estimated from NLDN CG flashes using 4 thunder audibility approximations: 5 and 10 nautical mile (n mi; 1 n mi = 1.852 km) audibility ranges, and minima of 1 and 2 flashes within the audibility range. The 26-yr period examined is longer than previous studies using NLDN data, and the TD results can be compared directly to climatologies derived from surface weather observations dating back to the late 1890s. Results based on the abundant NLDN data avoid limitations introduced by the coarse horizontal resolution of surface observations inherent in pre-NLDN TD climatologies. Annual mean flash density and annual and monthly mean TD distributions are derived from almost 568 million NLDN CG flashes. A mean annual maximum of more than 16 flashes km−2 is found near Tampa, Florida. The mean annual TD maximum of 113 days (from at least 2 flashes within 10 n mi) occurs in southern Florida. Regions exceeding 70 TDs are found from eastern Texas eastward into Florida, and over the southern Rocky Mountains. Large positive deviations from the mean number of TDs extend from Texas northwestward into Colorado during 2003–07, followed by large negative deviations over the same region during 2008–12. Both deviation patterns are similar to expected summertime precipitation anomaly patterns over the United States during El Niño and La Niña years, respectively.

scholarly journals Where Is the Real Cloud-to-Ground Lightning Maximum in North America?

2005 ◽  
Vol 20 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Martin J. Murphy ◽  
Ronald L. Holle
Keyword(s):  
Detection Efficiency ◽  
Local Maximum ◽  
Propagation Model ◽  
Model Parameters ◽  
Lightning Flash ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
Northwestern Mexico ◽  
Signal Normalization ◽  
Relative Detection

Abstract A local maximum in cloud-to-ground (CG) lightning flash density over northwestern Mexico as measured by the U.S. National Lightning Detection Network is examined in detail. Corrections are derived for the relative detection efficiency of the network in this region that is outside the perimeter of the sensors. The need to adjust the parameters of the signal normalization model used for the network is also documented. New propagation model parameters are employed to derive relative detection efficiency corrections for northwestern Mexico and these are then used to show that the actual CG flash density over the region significantly exceeds that observed in Florida, the area with the highest flash density within the perimeter of the network.

scholarly journals The Pseudoscorpions of Illinois

1949 ◽  
Vol 24 (1-4) ◽  
pp. 413-500 ◽  
Author(s):  
C. Clayton Hoff
Keyword(s):  
United States ◽  
Natural Habitat ◽  
Habitat Preferences ◽  
The United States ◽  
Accurate Information ◽  
North Central ◽  
Taxonomic Importance ◽  
Central United States ◽  
Identification Of Species ◽  
Made In

Pseudoscorpions are minute animals only a few millimeters long, with the general appearance of diminutive scorpions except that they have no tails. They belong to the large phylum of joint-legged animals, the Arthropoda, and to the class Arachnida. which, in addition to the pseudoscorpions, embraces the spiders, mites, ticks, scorpions, and other related groups. Pseudoscorpions are seclusive in habit, occurring in soil cover and rotten logs, under bark, and in similar places out of doors: one species is found in houses. In their natural habitat, these little brown animals arc difficult to see. especially when they draw in their legs and "play possum." In this position they look like little specks of dirt. Probably because pseudoscorpions are inconspicuous, few collections of the group have been made in the past, and the fauna, at least of North America, and especially of the central and north-central United States, has remained scantily known. The object of this report is twofold, first to present illustrated keys and descriptions for the identification of species in this region, and, secondly, to summarize information regarding the distribution, biology, and habitat preferences of the species. As an aid in use of the keys, a section has been included on morphology, in which the structures now considered of major taxonomic importance are explained. Summarizing the distribution has been especially difficult because many identifications made prior to Chamberlin's work are probably incorrect and should be rechecked before they are cited. Because of this situation there is little accurate information to serve as a guide in foretelling what additional described species may be collected in Illinois. In order to make this report of wide application, the keys have been made to include all the genera known from the central and northeastern portions of the United States and adjacent portions of Canada.

Paddlefish Management, Propagation, and Conservation in the 21st Century

2009 ◽  
Keyword(s):  
United States ◽  
The United States ◽  
Fish Production ◽  
Single Source ◽  
Spawning Habitat ◽  
Domestic Consumption ◽  
Central United States ◽  
History Of ◽  
Food Fish ◽  
Aquaculture Production

<em>Abstract</em>.—Paddlefish <em>Polyodon spathula </em>populations in North America have long been exploited commercially for meat and roe; however, the history of paddlefish propagation and culture is more recent. Early efforts to artificially propagate and culture paddlefish were motivated by conservation following the construction of dams and destruction of spawning habitat on major rivers of the central United States. From these beginnings, paddlefish propagation and the species itself have spread from native U.S. waters to other countries, including Russia and China. In the United States, conservation is still an important aspect of paddlefish culture, although sport fishing and aquaculture production have been added to the mix. However, in those countries where paddlefish have been introduced, the motivation has been the perceived potential for producing food for domestic consumption and valuable products for export, including one of the most exotic and expensive food products in today’s world—caviar. The collective efforts of state and federal hatchery personnel in the United States, along with university researchers from the United States and worldwide have resulted in a more complete body of information on paddlefish propagation and culture. Included in this collection are methods for handling broodstock, induced spawning, and nursery stages of production, along with cryopreservation of milt and manipulation of sex ratios in the hatchery to produce a preponderance of female fish. We have assembled this collection here to provide a single source reference and have added information concerning hatchery design, regulations, and the grow-out stages of aquaculture food fish production.

scholarly journals Positivity Rates of in Vitro Inhalant/ Respiratory and Food Allergy Tests in the Northern Midwestern United States

2018 ◽  
Vol 97 (9) ◽  
pp. 296-322 ◽  
Author(s):  
Michael S. Benninger ◽  
Thomas Daly ◽  
Kevin Graffmiller
Keyword(s):  
United States ◽  
Cleveland Clinic ◽  
The United States ◽  
Test Results ◽  
Dust Mites ◽  
Upper Midwest ◽  
Allergy Test ◽  
Wide Variability ◽  
Very High

Rates of allergy-test positivity vary by country and by regions within countries. Several studies have looked at allergy test results to determine the most common allergens. Many of these studies have been based on surveys or on studies of small numbers of tests. Positivity rates for allergy tests are poorly defined in the northern midwestern region of the United States. We conducted a study to identify the rates of positive allergy tests for both inhalant/respiratory allergens and food allergens in the upper Midwest. We extracted from our laboratory database the results of all test samples sent for one of eight allergen panels that had been analyzed between Sept. 1, 2014, and Sept. 1, 2015. All testing was performed at The Cleveland Clinic with the Phadia ImmunoCAP system. The percentage of positive tests, the distribution of the most frequently positive tests, and the class of in vitro responses were identified. A total of 148,628 test results for 63 different allergens were identified. Of the 125,190 tests for inhalant/respiratory allergens, the most frequently positive were dog dander (24% of tests), cat dander (23%), dust mites (23% for both Dermatophagoides pteronyssinus and Dermatophagoides farinae), and June grass (21%). Of the 23,438 food tests, the most frequently positive test results were for milk (18%), peanut (17%), wheat (16%), and egg white (15%). Most of the results fell into classes 1 through 3, although there was still a notable number of very high responses (class 5 and 6). These findings suggest that there is wide variability in the positivity of in vitro allergy tests and that the likelihood of a positive result in screening panels can be estimated. Evaluating such rates will help identify the most and least common allergens and will help to cost-effectively refine allergy screening panels.

scholarly journals Performance of Landscape Roses Grown with Minimal Input in the North-central, Central, and South-central United States

2017 ◽  
Vol 27 (5) ◽  
pp. 718-730 ◽  
Author(s):  
David C. Zlesak ◽  
Randy Nelson ◽  
Derald Harp ◽  
Barbara Villarreal ◽  
Nick Howell ◽  
...  
Keyword(s):  
United States ◽  
National Level ◽  
The United States ◽  
The South ◽  
Flower Number ◽  
North Central ◽  
The North ◽  
South Central ◽  
Central United States ◽  
Plant Hardiness

Landscape roses (Rosa sp.) are popular flowering shrubs. Consumers are less willing or able to maintain landscape beds than in years past and require plants that are not only attractive, but well-adapted to regional climatic conditions, soil types, and disease and pest pressures. Marketing and distribution of rose cultivars occurs on a national level; therefore, it is difficult for U.S. consumers in the U.S. Department of Agriculture (USDA) Plant Hardiness Zones 3 to 5 to identify well-adapted, cold-hardy cultivars. Identifying suitable cultivars that have strong genetic resistance to pests and disease and that will tolerate temperature extremes without winter protection in the USDA Plant Hardiness Zones 3 to 5 is of tremendous value to consumers and retailers in northern states. Twenty landscape rose cultivars, primarily developed in north-central North America, were evaluated at five locations in the United States (three in the north-central United States, one in the central United States, and one in the south-central United States) using the low-input, multiyear Earth-Kind® methodology. Six roses had ≥75% plant survival at the end of the study and were in the top 50% of performers for overall mean horticultural rating at each of the three north-central U.S. sites: ‘Lena’, ‘Frontenac’, ‘Ole’, ‘Polar Joy’, ‘Sunrise Sunset’, and ‘Sven’. Five of these six roses met the same criteria at the central United States (exception ‘Lena’) and the south-central United States (exception ‘Polar Joy’) sites. Cultivar, rating time, and their interaction were highly significant, and block effects were not significant for horticultural rating for all single-site analyses of variance. Significant positive correlations were found between sites for flower number, flower diameter, and overall horticultural rating. Significant negative correlations were found between flower number and diameter within each site and also between black spot (Diplocarpon rosae) lesion size from a previous study and overall horticultural rating for three of the five sites. Cane survival ratings were not significantly correlated with overall horticultural rating, suggesting some cultivars can experience severe winter cane dieback, yet recover and perform well. Data from this study benefit multiple stakeholders, including nurseries, landscapers, and consumers, with evidence-based regional cultivar recommendations and breeders desiring to identify regionally adapted parents.

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