scholarly journals An 18-year climatology of derechos in Germany

2019 ◽  
Author(s):  
Christoph P. Gatzen ◽  
Andreas H. Fink ◽  
David M. Schultz ◽  
Joaquim G. Pinto
Keyword(s):  
North Sea ◽  
Mixed Layer ◽  
Convective Available Potential Energy ◽  
Vertical Wind Shear ◽  
Warm Season ◽  
The United States ◽  
Cold Season ◽  
Central Germany ◽  
The North ◽  
The North Sea

Abstract. Derechos are high-impact convective wind events that can cause fatalities and widespread losses. In this study, 40 derechos affecting Germany between 1997 and 2014 are analysed to estimate the derecho risk. Similar to the United States, Germany is affected by two derecho types. The first derecho type forms in south-westerly 500-hPa flow downstream of intense west-European troughs and accounts for 22 of the 40 derechos. These derechos are named warm-season type due to their peak occurrence in June and July. Warm-season type derechos frequently start over southwestern Germany in the afternoon and move either eastward along the Alpine forelands or north-eastward across southern central Germany. Only one warm-season derecho moved across the North Sea and one moved across the Baltic Sea in the 18-year period. Proximity soundings of German warm-season type derechos indicate strong deep-layer vertical wind shear with a median of 20 m s−1 0–6-km shear and mixed-layer Convective Available Potential Energy (mixed-layer CAPE) between 20 and 2600 J kg−1 with a median around 500 J kg−1. The second derecho type forms in north-westerly 500-hPa flow and accounts for 18 of the 40 derechos. These derechos form in strong north-westerly flow, frequently in association with mid-tropospheric PV intrusions. They are named cold-season type because they are associated with a secondary peak from December to February. Cold-season type derechos start over or close to the North Sea and primarily affect north and central Germany; their start time is not strongly related to the peak of diurnal heating. Proximity soundings indicate high-shear–low-CAPE environments with a median 0–6-km shear of 35 m s−1 and a median mixed-layer CAPE of 3 J kg−1. Environmental CAPE is zero in almost half of cold-season type proximity soundings. Fifteen warm-season type and nine cold-season type derechos had wind gusts reaching 33 m s−1 in at least at three locations. Although warm-season derechos are more frequent, the path length of cold-season type derechos is on average 1.4 times longer. Thus, these two types of German derechos are likely to have similar impacts.

scholarly journals An 18-year climatology of derechos in Germany

2020 ◽  
Vol 20 (5) ◽  
pp. 1335-1351 ◽  
Author(s):  
Christoph P. Gatzen ◽  
Andreas H. Fink ◽  
David M. Schultz ◽  
Joaquim G. Pinto
Keyword(s):  
Mixed Layer ◽  
Convective Available Potential Energy ◽  
Vertical Wind Shear ◽  
Warm Season ◽  
The United States ◽  
Cold Season ◽  
Start Time ◽  
Central Germany ◽  
The North ◽  
Wind Events

Abstract. Derechos are high-impact convective wind events that can cause fatalities and widespread losses. In this study, 40 derechos affecting Germany between 1997 and 2014 are analyzed to estimate the derecho risk. Similar to the United States, Germany is affected by two derecho types. The first, called warm-season-type derechos, form in strong southwesterly 500 hPa flow downstream of western European troughs and account for 22 of the 40 derechos. They have a peak occurrence in June and July. Warm-season-type derechos frequently start in the afternoon and move either eastward along the Alpine forelands or northeastward across southern central Germany. Associated proximity soundings indicate strong 0–6 and 0–3 km vertical wind shear and a median of mixed-layer convective available potential energy (mixed-layer CAPE) around 500 J kg−1. The second derecho type, the cold-season-type derecho, forms in strong northwesterly 500 hPa flow, frequently in association with mid-tropospheric potential vorticity (PV) intrusions, and accounts for 18 of the 40 derechos. They are associated with a secondary peak from December to February. Cold-season-type derechos start over or close to the North Sea and primarily affect northern and central Germany; their start time is not strongly related to the peak of diurnal heating. Proximity soundings indicate high-shear–low-CAPE environments. A total of 15 warm-season-type and 9 cold-season-type derechos had wind gusts reaching 33 m s−1 in at least three locations. Although warm-season derechos are more frequent, the path length of cold-season-type derechos is on average 1.4 times longer. Thus, these two types of German derechos are likely to have similar impacts.

RESOURCE SHARING AND STRATEGIC ALLIANCES-REDUCTION OF OILFIELD COSTS THROUGH INNOVATIVE SUPPLY CHAIN MANAGEMENT

1998 ◽  
Vol 38 (1) ◽  
pp. 570
Author(s):  
A.R.J. Schenk
Keyword(s):  
Supply Chain ◽  
Supply Chain Management ◽  
North Sea ◽  
Strategic Alliances ◽  
Resource Sharing ◽  
Oil And Gas Industry ◽  
The United States ◽  
Chain Management ◽  
The North ◽  
The North Sea

Supply chain management is the relatively recently implemented concept of managing an integrated supply function from production of a product or service to its receipt by its ultimate end user.This management philosophy has revolutionised production and manufacturing industries throughout the world, and has brought about dramatic efficiency improvements, with similar effects upon reducing overall costs. Traditionally, this was an area that was considered of low priority, presenting little opportunity for value adding or innovation, and characterised by adversarial, uncompetitive management techniques.Similarly, in the oil and gas industry, especially in the North Sea and the Gulf of Mexico, extended supply chains have necessitated a re-evaluation of the mechanisms used not only for provision of the supply service, but in the relationship between the operator and the service provider. Most notable examples being the CRINE (Cost Reduction Initiative for the New Era) initiative in the United Kingdom and Chevron Corporation's (one of West Australian Petroleum's participants and also its technical advisor) CSQIP (Chevron Supplier Quality Improvement Process) methodology.This paper will concern itself therefore with the application of cutting edge Supply Chain Management techniques garnered from both the North Sea and the United States. Focussing specifically upon alliancing/partnering, resource sharing and outsourcing, upon West Australian Petroleum Pty Limited (WAPET) and its respective contractors.It will seek to show that through innovative use of current supply chain management tools, as well as imaginative 'out of the box' thinking by WAPET personnel and contractor personnel alike, significant cost reductions and performance improvements can be brought to bear on oilfield operating costs.

Mixed-layer kaolinite-illite-vermiculite in North Sea shales

Clay Minerals ◽  
1999 ◽  
Vol 34 (2) ◽  
pp. 333-344 ◽  
Author(s):  
B. A. Sakharov ◽  
H. Lindgreen ◽  
A. L. Salyn ◽  
V. A. Drits
Keyword(s):  
North Sea ◽  
Mixed Layer ◽  
Coherent Scattering ◽  
Upper Jurassic ◽  
The North ◽  
Dominant Component ◽  
The North Sea ◽  
Xrd Patterns ◽  
Layer Mineral ◽  
Random Alternation

AbstractThe finest fractions of Upper Jurassic shales from the North Sea and onshore Denmark contain 80–90% of an illite-smectite-vermiculite (I-S-V) mixed-layer mineral and, in addition a phase which has X-ray diffraction (XRD) peaks at 7.20–7.26 Å and 3.56–3.58 Å in air- dried and glycolated specimens. This phase may be a fine kaolinite with a small thickness of coherent scattering domains (CSDs) or alternatively a mixed-layer mineral which has kaolinite as the dominant component. For one sample from the Norwegian well 9/4-3, these alternatives are investigated using the multi-specimen method by which agreement between the experimental pattern and the pattern calculated for one and the same structure is obtained for each of several specimens saturated with different cations and with/without glycolation. It is demonstrated that the modelled XRD patterns for a kaolinite-illite-vermiculite (K-I-V) structure having 0.94 kaolinite, 0.03 illite and 0.03 vermiculite layers and random alternation fit the experimental patterns.

scholarly journals Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health

2009 ◽  
Vol 6 (4) ◽  
pp. 8411-8453 ◽  
Author(s):  
N. Greenwood ◽  
E. R. Parker ◽  
L. Fernand ◽  
D. B. Sivyer ◽  
K. Weston ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
North Sea ◽  
Mixed Layer ◽  
Ecosystem Health ◽  
Bottom Water ◽  
Dissolved Oxygen Concentration ◽  
The North ◽  
The North Sea ◽  
Oxygen Concentrations

Abstract. This paper presents new results from high temporal resolution observations over two years (2007 and 2008) from instrumented moorings deployed in the central North Sea, at the Oyster Grounds and on the northern slope of Dogger Bank (North Dogger). The water column was stratified in the summer at both sites, leading to limited exchange of the water in the bottom mixed layer. Data from these moorings revealed the variable nature of summer oxygen depletion at the Oyster Grounds. The combination of in situ and ship-based measurements allowed the physical and biological conditions leading to decreasing dissolved oxygen concentrations in bottom water to be examined. The concentration of dissolved oxygen in the bottom water at both sites was observed to decrease throughout the summer period after the onset of stratification. Depleted dissolved oxygen concentration (6.5 mg l−1, 71% saturation) was measured at the North Dogger, a site which is not significantly influenced by anthropogenic nutrient inputs. Lower oxygen saturation (5.2 mg l−1, 60% saturation) was measured for short durations at the Oyster Grounds. Increasing bottom water temperature accounted for 55% of the decrease in dissolved oxygen concentration at the Oyster Grounds compared to 10% at North Dogger. Dissolved oxygen concentration in bottom water at the Oyster Grounds was shown to be strongly influenced by short term events including storm events and pulses of biomass input. In contrast, dissolved oxygen concentration in bottom water at the North Dogger reflected longer seasonal processes such as gradual temperature increases and a more steady supply of biomass to the bottom mixed layer. The differences between the study sites shows the need for an improved understanding of the mechanisms driving these processes if the use of oxygen in marine management and ensuring ecosystem health is to be meaningful and successful in the future. These observations provide greater understanding of the nature of the depletion in bottom oxygen concentration in the North Sea.

Flying Boat Construction

1921 ◽  
Vol 25 (128) ◽  
pp. 385-420
Keyword(s):  
United States ◽  
North Sea ◽  
United States Navy ◽  
The United States ◽  
The North ◽  
Boat Building ◽  
The World ◽  
The North Sea ◽  
Naval Architect ◽  
Design And Construction

The design and construction of light hulls and floats suitable for flying boats and seaplanes is a very highly specialised branch of shipbuilding. This being the case, all matters pertaining to same Should be in the hands of naval architects. At a recent lecture before this Society, Commander Hunsaker, of the United States Navy, stated that British aircraft designers followed the naval architect's methods more than in any other country; he thought this was natural as he gave us the credit of being the first maritime power of the world. This may be perfectly true with regard to airships, but I cannot endorse his opinion that the majority of flying boats built in this country show the impress of the trained hand of a naval architect. I do not imply that the American boats are superior to ours, as for instance, a large American boat with twin engines built in the United States, which we used for the North Sea patrol, was by no means typical of good boat-building ; there were no less than four consecutive planks butted—not even scarfed—on the same timber, which had a siding of 5/8in., the line of butts being in line with the step where the boat was naturally weakest.

scholarly journals The Safe and Efficient Development of Offshore Transboundary Hydrocarbons: Best Practices from the North Sea and Their Application to the Gulf of Mexico

2019 ◽  
Author(s):  
Elise Aldendifer ◽  
McKenzie Coe ◽  
Taylor Faught ◽  
Ian Klein ◽  
Peter Kuylen ◽  
...  
Keyword(s):  
United States ◽  
Gulf Of Mexico ◽  
North Sea ◽  
Oil And Gas ◽  
The United States ◽  
Framework Agreement ◽  
The North ◽  
The North Sea ◽  
Regulatory Regimes ◽  
Transboundary Resources

Offshore hydrocarbon resources have been developed for many decades, and with technology improvements, many fields which were once impossible to develop, are now economically and technologically feasible. This has led to a growing difficulty in determining the legislative and regulatory framework for resources that straddle the recognized borders between two states. In this paper, we examine a successful framework agreement governing the transboundary resources between the United Kingdom (“U.K.”) and Norway in the North Sea, and the agreement between the United States and Mexico governing the Gulf of Mexico. Following the 2013 Energy Reform, the Mexican energy sector has been revitalized, leading to greater exploration, development, and production than ever before. This means that in the near future transboundary resources may be licensed for production, bringing the issues highlighted in this paper to the attention of multiple government and international entities. This paper seeks to recommend improvements to the transboundary framework in the Gulf of Mexico based on the successful framework agreement utilized in the North Sea. This paper begins by introducing international law for offshore resources in Part II. Part III discusses the offshore regulatory regimes in the U.K. and Norway, analyzing how the two states have successfully used bilateral agreements to facilitate cooperation regarding effective exploitation and apportionment of costs from cross-boundary offshore oil and gas projects in the North Sea. Part IV discusses the offshore regulatory regimes in the United States and Mexico and analyzes the current transboundary agreement in place for the Gulf of Mexico. Part V compares the transboundary agreement governing the North Sea and the same governing the Gulf of Mexico. We highlight the major differences in the agreements and suggest changes to the Gulf of Mexico agreement based on the successful North Sea agreement. Finally, this paper concludes and provides key policy recommendations to improve the rules and regulations surrounding the exploitation of transboundary hydrocarbons in the Gulf of Mexico.

scholarly journals The Lower Palaeozoic shale gas play in Denmark

1969 ◽  
Vol 31 ◽  
pp. 19-22 ◽  
Author(s):  
Niels H. Schovsbo ◽  
Arne T. Nielsen ◽  
Donald L. Gautier
Keyword(s):  
North Sea ◽  
Best Practice ◽  
The United States ◽  
United States Geological Survey ◽  
The North ◽  
Alum Shale ◽  
Wide Range ◽  
The North Sea ◽  
Potential Resource ◽  
Lower Palaeozoic

The unconventional gas resources in the Lower Palaeozoic shale of Denmark were recently assessed by the United States Geological Survey (USGS; Gautier et al. 2013). Assuming unrestricted application of best practice current technology, recoverable gas resources of 0 to 130 × 109 Nm3 gas were estimated onshore (mean = 67 × 109 Nm3 gas) and 0 to 228 × 109 Nm3 gas were estimated offshore (mean = 119 × 109 Nm3 gas), i.e. a total estimated mean of 186 × 109 Nm3 gas (Nm3: normal cubic metre, unit used for natural gas at 0°C and 101.325 kPa). Nearly all of this potential resource is assumed to be contained in the Cambro-Ordovician Alum Shale. The wide range of estimates reflects the sparse data and the geological uncertainty inherent in the still untested play. The estimated mean quantity of gas resource is comparable to the total volume of gas produced from the Danish part of the North Sea during 1972–2011 and twice the amount of the estimated remaining reserves of conventional gas in the Danish part of the North Sea.

Sequential structure transformation of illite-smectite-vermiculite during diagenesis of Upper Jurassic shales from the North Sea and Denmark

Clay Minerals ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 351-371 ◽  
Author(s):  
V. A. Drits ◽  
B. A. Sakharov ◽  
H. Lindgreen ◽  
A. Salyn
Keyword(s):  
North Sea ◽  
Mixed Layer ◽  
Structural Characteristics ◽  
Upper Jurassic ◽  
Interlayer Cation ◽  
X Ray ◽  
The North ◽  
Sequential Structure ◽  
The North Sea ◽  
Multicomponent Program

AbstractFor mixed-layer clay fractions from the North Sea and Denmark, X-ray diffractograms have been recorded for specimens saturated with Mg, Ca, Na and NH4, both airdry and intercalated with ethylene glycol, and the patterns have been computer-simulated with a multicomponent program. The mixed-layer fractions consist of an illite-smectite-vermiculite (I-S-V) phase constituting ~90% of the fraction and a kaolinite-illite-vermiculite (K-I-V) phase. For each I-S-V, the degree of swelling in swelling interlayers depends on both interlayer cation and glycolation, whereas the amount of non-swelling illite and swelling interlayers and the interstratification parameters are constant. Based on structural characteristics and the degree of diagenetic transformation, the samples investigated can be divided into three groups. The I-S-V of group one is predominantly detrital and has 0.69-0.73 illite, 0.26-0.20 smectite and 0.04-0.07 vermiculite interlayers, the illite, smectite and vermiculite interlayers being segregated. The I-S-V of group two has been diagenetically transformed and has 0.80 illite, 0.12 smectite and 0.08 vermiculite interlayers, the vermiculite interlayers being segregated whereas the illite and smectite have the maximum ordering possible for R = 1. The I-S-V of group three has been further transformed during diagenesis and has 0.84 illite, 0.08 smectite and 0.08 vermiculite interlayers. Statistical calculations demonstrate that the I-S-V transformation can be described as a single interlayer transformation (SIT) within the crystallites.

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