scholarly journals A Climatology of Northern Hemisphere Blocking

2006 ◽  
Vol 19 (6) ◽  
pp. 1042-1063 ◽  
Author(s):  
David Barriopedro ◽  
Ricardo García-Herrera ◽  
Anthony R. Lupo ◽  
Emiliano Hernández
Keyword(s):  
Conceptual Model ◽  
Northern Hemisphere ◽  
Additional Information ◽  
Teleconnection Patterns ◽  
The North ◽  
Blocking Mechanisms ◽  
The Individual ◽  
Dynamical Connection

Abstract In this paper a 55-yr (1948–2002) Northern Hemisphere blocking climatology is presented. Traditional blocking indices and methodologies are revised and a new blocking detection method is designed. This algorithm detects blocked flows and provides for a better characterization of blocking events with additional information on blocking parameters such as the location of the blocking center, the intensity, and extension. Additionally, a new tracking procedure has been incorporated following simultaneously the individual evolution of blocked flows and identifying coherently persistent blocked patterns. Using this method, the longest known Northern Hemisphere blocking climatology is obtained and compared with previous studies. A new regional classification into four independent blocking sectors has been obtained based on the seasonally preferred regions of blocking formation: Atlantic (ATL), European (EUR), West Pacific (WPA), and East Pacific (EPA). Global and regional blocking characteristics have been described, examining their variability from the seasonal to interdecadal scales. The global long-term blocking series in the North Hemisphere showed a significant trend toward weaker and less persistent events, as well as regional increases (decreases) in blocking frequency over the WPA (ATL and EUR) sector. The influence of teleconnection patterns (TCPs) on blocking parameters is also explored, being confined essentially to wintertime, except in the WPA sector. Additionally, regional blocking parameters, especially frequency and duration, are sensitive to regional TCPs, supporting the regional classification obtained in this paper. The ENSO-related blocking variability is evident in blocking intensities and preferred locations but not in frequency. Finally, the dynamical connection between blocking occurrence and regional TCPs is examined through the conceptual model proposed by Charney and DeVore. Observational evidence of a dynamical link between the asymmetrical temperature distributions induced by TCPs and blocking variability is provided with a distinctive contrast “warm ocean/cold land” pattern favoring the blocking occurrence in winter. However, the conceptual model is not coherent in the WPA sector, suggesting different blocking mechanisms operating in this sector.

scholarly journals Spatiotemporal Variability and Trends in Extreme Temperature Events in Finland over the Recent Decades: Influence of Northern Hemisphere Teleconnection Patterns

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Masoud Irannezhad ◽  
Hamid Moradkhani ◽  
Bjørn Kløve
Keyword(s):  
Northern Hemisphere ◽  
Extreme Temperature ◽  
Cold Temperature ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
Temperature Extremes ◽  
Warm Temperature ◽  
Teleconnection Patterns ◽  
The North ◽  
Temperature Indices

Fifteen temperature indices recommended by the ETCCDI (Expert Team on Climate Change Detection and Indices) were applied to evaluate spatiotemporal variability and trends in annual intensity, frequency, and duration of extreme temperature statistics in Finland during 1961–2011. Statistically significant relationships between these high-resolution (10 km) temperature indices and seven influential Northern Hemisphere teleconnection patterns (NHTPs) for the interannual climate variability were also identified. During the study period (1961–2011), warming trends in extreme temperatures were generally manifested by statistically significant increases in cold temperature extremes rather than in the warm temperature extremes. As expected, warm days and nights became more frequent, while fewer cold days and nights occurred. The frequency of frost and icing days also decreased. Finland experienced more (less) frequent warm (cold) temperature extremes over the past few decades. Interestingly, significant lengthening in cold spells was observed over the upper part of northern Finland, while no clear changes are found in warm spells. Interannual variations in the temperature indices were significantly associated with a number of NHTPs. In general, warm temperature extremes show significant correlations with the East Atlantic and the Scandinavia patterns and cold temperature extremes with the Arctic Oscillation and the North Atlantic Oscillation patterns.

Creep Characterization Of Ceramic BGA

2004 ◽  
Vol 1 (2) ◽  
pp. 102-107
Author(s):  
Lewis S. Goldmann ◽  
Mukta Farooq
Keyword(s):  
Compressive Loading ◽  
Compressive Force ◽  
Creep Model ◽  
Equivalent Material ◽  
Geometric Stiffening ◽  
The Individual ◽  
Term Creep ◽  
Range Of Values

Long term creep of a ceramic ball grid array (CBGA) solder ball under compressive loading was investigated. An experiment was conducted with two levels of loading and four of temperature. Analysis of the data assumed the composite ball structure could be simulated by an interconnection having the same shape, but of a single equivalent material. Curve fitting determined the stress exponent and activation energy of the equivalent material in the Norton creep model; the values were consistent with the range of values of the individual components available in the literature. Nonlinearity of the change in ball height with time was hypothesized to be due to geometric stiffening, a hypothesis which was confirmed by a simplified model. The model may be used to estimate creep behavior of other ball geometries having the same material set. The final result of this work - a closed form equation describing height decrease as a function of compressive force, temperature and time - can be used to simplify complex modeling of an entire package, and as an aid in designing accelerated thermal cycles which appropriately synchronize solder creep and fatigue.

scholarly journals Characterization of Supraharmonic Emission from Three Different Electric Vehicle Charging Infrastructures in Time and Frequency Domain

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 394
Author(s):  
Tim Streubel ◽  
Christoph Kattmann ◽  
Adrian Eisenmann ◽  
Krzysztof Rudion
Keyword(s):  
Electric Vehicle ◽  
Power Quality ◽  
Harmonic Distortion ◽  
Electric Vehicle Charging ◽  
Vehicle Charging ◽  
The Individual ◽  
The Impact ◽  
Distribution Grids

With the recent proliferation of electric vehicles (EVs), maintaining power quality within acceptable limits in future distribution grids will become a challenging task. A specific concern is the spread of Supraharmonics in the range from 2 to 150 kHz, generated by modern power electronic devices. In this paper, the long term Supraharmonic distortion from three differently sized electric vehicle charging infrastructures is analyzed in frequency and time domain. At the monitored sites several interruptions of EV charging processes were observed due to poor power quality. It was found that vehicles disconnect when exposed to high levels of harmonic distortion. Moreover, the impact of the charging EVs on the Supraharmonic distortion and the interaction with the background distortion for the individual sites is discussed. Results show that a general increase in Supraharmonics emission can be expected due to the rising number of EVs. However, measurements also indicate that damping effects can occur for certain load configurations.

scholarly journals Changing Northern Hemisphere Storm Tracks in an Ensemble of IPCC Climate Change Simulations

2008 ◽  
Vol 21 (8) ◽  
pp. 1669-1679 ◽  
Author(s):  
U. Ulbrich ◽  
J. G. Pinto ◽  
H. Kupfer ◽  
G. C. Leckebusch ◽  
T. Spangehl ◽  
...  
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Climate Models ◽  
Global Climate ◽  
Storm Track ◽  
Global Climate Models ◽  
The North ◽  
Storm Track Activity ◽  
Eastern North Atlantic ◽  
The Individual

Abstract Winter storm-track activity over the Northern Hemisphere and its changes in a greenhouse gas scenario (the Special Report on Emission Scenarios A1B forcing) are computed from an ensemble of 23 single runs from 16 coupled global climate models (CGCMs). All models reproduce the general structures of the observed climatological storm-track pattern under present-day forcing conditions. Ensemble mean changes resulting from anthropogenic forcing include an increase of baroclinic wave activity over the eastern North Atlantic, amounting to 5%–8% by the end of the twenty-first century. Enhanced activity is also found over the Asian continent and over the North Pacific near the Aleutian Islands. At high latitudes and over parts of the subtropics, activity is reduced. Variations of the individual models around the ensemble average signal are not small, with a median of the pattern correlation near r = 0.5. There is, however, no evidence for a link between deviations in present-day climatology and deviations with respect to climate change.

scholarly journals River as a flow of commodities: The reasoning behind the third Danube regulation in Bratislava by Enea Grazioso Lanfranconi

2021 ◽  
Vol 26 (4) ◽  
pp. 46-54
Author(s):  
Monika Bočková
Keyword(s):  
City Planning ◽  
Planning Process ◽  
Statistical Data ◽  
Theoretical Work ◽  
New Paradigm ◽  
The Third ◽  
The North ◽  
The Individual ◽  
The 19Th Century

Abstract The channel of most of the rivers is the result of long-term human endeavour to modify their shape. This paper focuses on the flow of commodities juxtaposed with the physical water flow of the river that has served over centuries as one of the main means of goods transport. The topic is closely observed on the example of the Danube regulation in Bratislava at the end of the nineteenth century and the transformation of the river into a canal. The reasons for the individual interventions in the natural riverbed differed. The third regulation (1886 - 1896) was meant to add the missing part of the canal on the route between the North and Black Seas, which would be fully adapted for freight transport by steamer. The 19th century has introduced a new paradigm to city planning. In the belief in technical innovation, the planning process was undertaken by engineers. The paper places in confrontation the oeuvre of two engineers, Charles-Joseph Minard and Enea Grazioso Lanfranconi. While the former, a French civil engineer, brought a unique way of visualizing the flow of goods between territories based on statistical data, the latter, a Hungarian hydraulic engineer, is the author of the third regulation of the Danube in the section between Devín (Theben) and Gönyű (Gönyö). For the purpose of the paper, the original theoretical work of Enea Grazioso Lanfranconi was translated and analysed. Selected data from Lanfranconi’s work was interpreted visually.

scholarly journals CARINA-Oxygen: a new high-quality oxygen database for the Atlantic Ocean

2009 ◽  
Vol 2 (1) ◽  
pp. 103-135 ◽  
Author(s):  
I. Stendardo ◽  
N. Gruber ◽  
A. Körtzinger
Keyword(s):  
Data Base ◽  
North Atlantic ◽  
Deep Ocean ◽  
Atlantic Region ◽  
The North ◽  
Term Change ◽  
Sample Density ◽  
The Individual ◽  
Oxygen Measurements

Abstract. In the CARINA project, a new dataset with many previously unpublished hydrographic data from the Atlantic, Arctic and Southern Ocean was assembled and subjected to careful quality control (QC) procedures. In this paper, we present the dissolved oxygen measurements in the Atlantic region of the database and describe in detail the secondary QC procedures that aim to ensure optimal consistency between different cruises in order to permit studies of long-term change. The secondary QC is based on a cross-over analysis, i.e. the comparison of deep ocean data at places that were sampled by different cruises at different times. Initial adjustments to the individual cruises were then determined by an inverse procedure that computes a set of adjustments that requires the minimum amount of adjustment and at the same time reduces the offsets in an optimal manner. The initial adjustments were then reviewed by the CARINA members, and only those that passed the following two criteria were adopted: (i) the region not subject to substantial temporal variability, and (ii) the adjustment must be based on at least three stations from each cruise. No adjustment was recommended for cruises that did not fit these criteria. The final CARINA-Oxygen database has 113005 oxygen samples from 9535 stations obtained during 98 cruises covering three decades. The sampling density of the oxygen data is particularly good in the North Atlantic north of about 40° N especially after 1987. In contrast, the sample density in the South Atlantic is much lower. Some cruises appear to have poor data quality, and were subsequently omitted from the adjusted data base. Of the data included in the adjusted data base, 20% were adjusted with a mean adjustment of 2%.

scholarly journals Prediction Skill of the NAO and PNA from Daily to Seasonal Time Scales

2007 ◽  
Vol 20 (10) ◽  
pp. 1957-1975 ◽  
Author(s):  
Åke Johansson
Keyword(s):  
Time Scales ◽  
Northern Hemisphere ◽  
Horizontal Resolution ◽  
Forecast Skill ◽  
Teleconnection Patterns ◽  
Modes Of Variability ◽  
The North ◽  
Negative Skewness ◽  
Medium Range ◽  
Two Indices

Abstract The skill of state-of-the-art operational dynamical models in predicting the two most important modes of variability in the Northern Hemisphere extratropical atmosphere, the North Atlantic Oscillation (NAO) and Pacific–North American (PNA) teleconnection patterns, is investigated at time scales ranging from daily to seasonal. Two uncoupled atmospheric models used for deterministic forecasting in the short to medium range as well as eight fully coupled atmosphere–land–ocean forecast models used for monthly and seasonal forecasting are examined and compared. For the short to medium range, the level of forecast skill for the two indices is higher than that for the entire Northern Hemisphere extratropical flow. The forecast skill of the PNA is higher than that of the NAO. The forecast skill increases with the magnitude of the NAO and PNA indices, but the relationship is not pronounced. The probability density function (PDF) of the NAO and PNA indices is negatively skewed, in agreement with the distribution of skewness of the geopotential field. The models maintain approximately the observed PDF, including the negative skewness, for the first week. Extreme negative NAO/PNA events have larger absolute values than positive extremes in agreement with the negative skewness of the two indices. Recent large extreme events are generally well forecasted by the models. On the intraseasonal time scale it is found that both NAO and PNA have lingering forecast skill, in contrast to the Northern Hemisphere extratropical flow as a whole. This fact offers some hope for extended range forecasting, even though the skill is quite low. No conclusive positive benefit is seen from using higher horizontal resolution or coupling to the oceans. On the monthly and seasonal time scales, the level of forecast skill for the two indices is generally quite low, with the exception of winter predictions at short lead times.

Clostridium difficile -Associated Disease in Long-Term Care Facilities

1990 ◽  
Vol 11 (8) ◽  
pp. 434-438 ◽  
Author(s):  
David W. Bentley
Keyword(s):  
Clostridium Difficile ◽  
Clinical Manifestations ◽  
Gastrointestinal Infections ◽  
Term Care ◽  
Additional Information ◽  
Care Facilities ◽  
Definition Of ◽  
Pathological Event

Clostridium difficile is a major cause of gastrointestinal infections. In 1978, Bartlett and colleagues identified C difficile and its toxin as the cause of the antibiotic-associated pseudomembranous colitis (PMC). Within a few years, there was the development of a diagnostic assay, a description of a clinical and pathological spectrum of the disease, a definition of risk factors and characterization of the two toxins that account for the pathological event. Additional information regarding the microbiology, pathogenesis, clinical manifestations, diagnosis and treatment has rapidly developed. These features are beyond the scope of this report, and the reader is referred to several recent reviews.

scholarly journals Genetic Variability and Management in Nero di Parma Swine Breed to Preserve Local Diversity

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 538 ◽  
Author(s):  
Elena Mariani ◽  
Andrea Summer ◽  
Michela Ablondi ◽  
Alberto Sabbioni
Keyword(s):  
Genetic Diversity ◽  
Mean Value ◽  
Breeding Strategies ◽  
Term Survival ◽  
The North ◽  
Local Diversity ◽  
The Mean ◽  
The Individual

Nero di Parma is an endangered swine breed reared in the North of Italy which nowadays counts 1603 alive pigs. The aims of this study were (i) to explore the genetic diversity of the breed at pedigree level to determine the actual genetic structure, (ii) to evaluate the effectiveness of the breeding recovery project and (iii) to potentially propose breeding strategies for the coming generations. The pedigree dataset contained 14,485 animals and was used to estimate demographic and genetic parameters. The mean equivalent complete generations was equal to 6.47 in the whole population, and it reached a mean value of 7.94 in the live animals, highlighting the quality of the available data. Average inbreeding was 0.28 in the total population, whereas it reached 0.31 in the alive animals and it decreased to 0.27 if only breeding animals were considered. The rate of inbreeding based on the individual increase in inbreeding was equal to 7%. This study showed the effectiveness of the recovery project of the breed. Nevertheless, we found that inbreeding and genetic diversity have reached alarming levels, therefore novel breeding strategies must be applied to ensure long-term survival of this breed.

scholarly journals An Objective Satellite-Based Tropical Cyclone Size Climatology

2014 ◽  
Vol 27 (1) ◽  
pp. 455-476 ◽  
Author(s):  
John A. Knaff ◽  
Scott P. Longmore ◽  
Debra A. Molenar
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Historical Record ◽  
Maximum Intensity ◽  
Low Level ◽  
The North ◽  
Tangential Wind ◽  
Long Term Trends ◽  
The Individual

Abstract Storm-centered infrared (IR) imagery of tropical cyclones (TCs) is related to the 850-hPa mean tangential wind at a radius of 500 km (V500) calculated from 6-hourly global numerical analyses for North Atlantic and eastern North Pacific TCs for 1995–2011. V500 estimates are scaled using the climatological vortex decay rate beyond 500 km to estimate the radius of 5 kt (1 kt = 0.514 m s−1) winds (R5) or TC size. A much larger historical record of TC-centered IR imagery (1978–2011) is then used to estimate TC sizes and form a global TC size climatology. The basin-specific distributions of TC size reveal that, among other things, the eastern North Pacific TC basins have the smallest while western North Pacific have the largest TC size distributions. The life cycle of TC sizes with respect to maximum intensity shows that TC growth characteristics are different among the individual TC basins, with the North Atlantic composites showing continued growth after maximum intensity. Small TCs are generally located at lower latitudes, westward steering, and preferred in seasons when environmental low-level vorticity is suppressed. Large TCs are generally located at higher latitudes, poleward steering, and preferred in enhanced low-level vorticity environments. Postmaximum intensity growth of TCs occurs in regions associated with enhanced baroclinicity and TC recurvature, while those that do not grow much are associated with west movement, erratic storm tracks, and landfall at or near the time of maximum intensity. With respect to climate change, no significant long-term trends are found in the dataset of TC size.

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