The High-Pressure Area of November 1889 in Central Europe, with Remarks on High-Pressure Areas in General

Nature ◽  
1891 ◽  
Vol 43 (1116) ◽  
pp. 466-471
Author(s):  
WM. FERREL
Keyword(s):  
High Pressure ◽  
Central Europe ◽  
Pressure Area

scholarly journals Impact of Atmospheric Circulation on the Occurrence of Hot Nights in Central Europe

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 474 ◽  
Author(s):  
Arkadiusz Tomczyk
Keyword(s):  
Water Management ◽  
High Pressure ◽  
Central Europe ◽  
National Research Institute ◽  
Upper Troposphere ◽  
Atmospheric Research ◽  
Pressure Area ◽  
Environmental Prediction ◽  
The Waves ◽  
Minimum Air Temperature

The main goal of the study is to determine the pressure conditions that cause waves of hot nights in Central Europe. The goal was implemented on the basis of data from 1966 to 2015, made available by the Institute of Meteorology and Water Management—National Research Institute, Deutscher Wetterdienst and the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). A hot night was defined as a day with the minimum air temperature above 18 °C. In the analysed years, an increase in the number of hot nights was found, which was predominantly statistically significant within the studied area. The study shows that the occurrence of waves of hot nights in Central Europe was associated on average with the ridge of high pressure, within which a local high-pressure area developed. During the waves of hot nights, there were positive anomalies of heights of isobaric surfaces over the study area with a maximum in the upper troposphere.

scholarly journals Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Vincenzo Petrone ◽  
Adolfo Senatore ◽  
Vincenzo D'Agostino
Keyword(s):  
High Pressure ◽  
Film Thickness ◽  
Free Volume ◽  
Experimental Studies ◽  
Line Contact ◽  
Volume Model ◽  
Free Volume Model ◽  
Pressure Area ◽  
New Formulation ◽  
Lubricant Viscosity

This paper presents the application of an improved Yasutomi correlation for lubricant viscosity at high pressure in a Newtonian elastohydrodynamic line contact simulation. According to recent experimental studies using high pressure viscometers, the Yasutomi pressure-viscosity relationship derived from the free-volume model closely represents the real lubricant piezoviscous behavior for the high pressure typically encountered in elastohydrodynamic applications. However, the original Yasutomi correlation suffers from the appearance of a zero in the function describing the pressure dependence of the relative free volume thermal expansivity. In order to overcome this drawback, a new formulation of the Yasutomi relation was recently developed by Bair et al. This new function removes these concerns and provides improved precision without the need for an equation of state. Numerical simulations have been performed using the improved Yasutomi model to predict the lubricant pressure-viscosity, the pressure distribution, and the film thickness behavior in a Newtonian EHL simulation of a squalane-lubricated line contact. This work also shows that this model yields a higher viscosity at the low-pressure area, which results in a larger central film thickness compared with the previous piezoviscous relations.

Calculation Method of Lubricant Film Pressure Distribution of Axial Piston Pump Slippers

2013 ◽  
Vol 328 ◽  
pp. 629-633
Author(s):  
Ya Jun Wang
Keyword(s):  
High Pressure ◽  
Pressure Distribution ◽  
Mass Conservation ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Shearing Flow ◽  
Pump Speed ◽  
Pressure Area ◽  
The Difference ◽  
Axial Piston

A method is implemented to get the pressure distribution of the axial piston pump slipper. Slipper was seen as translating thrust bearing, taking slipper tilt and spin in account, based on finite volume method, hydrodynamic and hydrostatic pressure has been calculated by using the mass conservation principle. For a representative element volume, the difference flow was averaged by the difference flow between the tilting planes, and the shearing flow by slipper translating was averaged by the shearing flow between the tilting planes. The numerical calculating result based two liquid resistance assume was compared, the results showed that two methods have got the same pressure distribution schematics, and the high pressure area locates at the slipper titling direction, but for the pressure values at high pressure area, the second method is slightly higher than the first method, and that the higher pump speed were, the higher the pressure values, and at the same pump speed, the slipper spin speed affects slightly the pressure, and at the lower pump speed, the lubricant pressure tends to the hydrostatic lubrication.

scholarly journals NOCE MROŹNE W POZNANIU I ICH CYRKULACYJNE UWARUNKOWANIA

2018 ◽  
pp. 225-238
Author(s):  
ARKADIUSZ M. TOMCZYK
Keyword(s):  
Water Management ◽  
High Pressure ◽  
Central Europe ◽  
Air Temperature ◽  
National Research Institute ◽  
Pressure System ◽  
Air Masses ◽  
Circulation Types ◽  
Pressure Ridge ◽  
Minimum Air Temperature

The main purpose of this article was to determine the pressure situations and circulation types causing the occurrence of frosty nights in Poznań in the years 1966/67–2015/16. A night was assumed to be a frosty night with a minimum temperature below –10°C. The article uses the daily values of the minimum air temperature for the period of 1966–2016 for the station in Poznań. The data was provided by the Institute of Meteorology and Water Management – National Research Institute. In the analyzed years, 10 frosty nights were recorded on average every season. Conducted studies showed a decrease in their number, although these changes were not statistically significant. The average occurrence of frosty nights was associated with the presence of a high-pressure system over Central Europe, which developed within a high-pressure ridge extending over the majority of the continent. Such a pressure situation led to the advection of continental air masses from the eastern sector.

scholarly journals Research and application of supramolecular gel plugging agent in abnormal pressure reservoir

2021 ◽  
Vol 2045 (1) ◽  
pp. 012006
Author(s):  
B Baletabieke ◽  
Y X Gu ◽  
T Zhou ◽  
D X Duan ◽  
J T Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Oil And Gas ◽  
Adhesion Force ◽  
Fiber Composite ◽  
Low Pressure ◽  
Effective Rate ◽  
Pressure Zone ◽  
Composite Gel ◽  
Pressure Area ◽  
Strong Adhesion

Abstract The Aktobe project is the largest oil and gas producing area of PetroChina in Central Asia. However, after years of exploitation, the pressure of the reservoir has dropped, making it difficult to increase the production of a single well. Both the Kenkyak block and North Troyes block of the project have induced fractured leakage, and frequent leakage affects safe and efficient drilling and completion operations and production. Therefore, the research on leakage prevention and control technology is very necessary. This article focuses on the characteristics of the cracks in the high-pressure area of the Kenkyak block and the cracks in the low-pressure area of the North Troyes block. Aiming at the fracture characteristics of the high-pressure zone in the Kenkyak block and the low-pressure zone in North Troyes block, and taking advantage of the synergistic effect of supramolecules, a supramolecular plugging-while-drilling agent was developed based on the deformable fiber composite gel. It forms a strong adhesion plugging layer on the inner wall of the leakage channel through the strong adhesion force, and it achieves a good plugging effect. The 300-500mD sand disc bearing pressure could reach 700psi when adding 3% agent, and the bearing pressure of 3-5D permeability sand disc could reach above 450psi. A supramolecular static plugging agent was also developed based on the dilatant gel. It is rich in strong shear reversible gel with supramolecular structure, which guarantees its pumpability and plugging performance. The effective rate of one-time plugging is over 80%, and the viscosity is greatly reduced after the gel is broken for 72hr, which benefits the reservoir protection.

scholarly journals Overview of the synoptic and pollution situation over Europe during the EUCAARI-LONGREX field campaign

2010 ◽  
Vol 10 (8) ◽  
pp. 19129-19174 ◽  
Author(s):  
T. Hamburger ◽  
G. McMeeking ◽  
A. Minikin ◽  
W. Birmili ◽  
M. Dall'Osto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Central Europe ◽  
Number Concentration ◽  
Series Data ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Field Campaign ◽  
Accumulation Mode ◽  
Continental Scale

Abstract. The European integrated project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) focuses on understanding the interactions of climate and air pollution. As part of the EUCAARI intensive observational period, an aircraft field campaign (EUCAARI-LONGREX) was conducted in May 2008. The campaign aimed at studying the distribution and evolution of air mass properties on a continental scale. Airborne aerosol and trace gas measurements were performed aboard the German DLR Falcon 20 and the British FAAM BAe-146 aircraft. This paper outlines the meteorological situation over Europe during May 2008 and the temporal and spatial evolution of predominantly anthropogenic particulate pollution inside the boundary layer and the free troposphere. Time series data of six selected ground stations are used to discuss continuous measurements besides the single flights. The observations encompass total and accumulation mode particle number concentration (0.1–0.8 μm) and black carbon mass concentration as well as several meteorological parameters. Vertical profiles of total aerosol number concentration up to 10 km are compared to vertical profiles probed during previous studies. During the first half of May 2008 an anticyclonic blocking event dominated the weather over Central Europe. It led to increased pollutant concentrations within the centre of the high pressure inside the boundary layer. Due to long-range transport the accumulated pollution was partly advected towards Western and Northern Europe. The measured aerosol number concentrations over Central Europe showed in the boundary layer high values up to 14 000 cm−3 for particles in diameter larger 10 nm and 2300 cm−3 for accumulation mode particles during the high pressure period, whereas the middle free troposphere showed rather low concentrations of particulates. Thus a strong negative gradient of aerosol concentrations between the well mixed boundary layer and the clean middle troposphere occurred.

scholarly journals Overview of the synoptic and pollution situation over Europe during the EUCAARI-LONGREX field campaign

2011 ◽  
Vol 11 (3) ◽  
pp. 1065-1082 ◽  
Author(s):  
T. Hamburger ◽  
G. McMeeking ◽  
A. Minikin ◽  
W. Birmili ◽  
M. Dall'Osto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Central Europe ◽  
Number Concentration ◽  
Series Data ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Field Campaign ◽  
Accumulation Mode ◽  
Continental Scale

Abstract. In May 2008 the EUCAARI-LONGREX aircraft field campaign was conducted within the EUCAARI intensive observational period. The campaign aimed at studying the distribution and evolution of air mass properties on a continental scale. Airborne aerosol and trace gas measurements were performed aboard the German DLR Falcon 20 and the British FAAM BAe-146 aircraft. This paper outlines the meteorological situation over Europe during May 2008 and the temporal and spatial evolution of predominantly anthropogenic particulate pollution inside the boundary layer and the free troposphere. Time series data of six selected ground stations are used to discuss continuous measurements besides the single flights. The observations encompass total and accumulation mode particle number concentration (0.1–0.8 μm) and black carbon mass concentration as well as several meteorological parameters. Vertical profiles of total aerosol number concentration up to 10 km are compared to vertical profiles probed during previous studies. During the first half of May 2008 an anticyclonic blocking event dominated the weather over Central Europe. It led to increased pollutant concentrations within the centre of the high pressure inside the boundary layer. Due to long-range transport the accumulated pollution was partly advected towards Western and Northern Europe. The measured aerosol number concentrations over Central Europe showed in the boundary layer high values up to 14 000 cm−3 for particles in diameter larger 10 nm and 2300 cm−3 for accumulation mode particles during the high pressure period, whereas the middle free troposphere showed rather low concentrations of particulates. Thus a strong negative gradient of aerosol concentrations between the well mixed boundary layer and the clean middle troposphere occurred.

scholarly journals Occurrence and mechanisms of extreme winter air temperatures in the Arctic and surrounding continents

2020 ◽  
Author(s):  
Timo Vihma ◽  
Petteri Uotila ◽  
Tuomas Naakka ◽  
Tiina Nygård
Keyword(s):  
High Pressure ◽  
North America ◽  
Sea Ice ◽  
Central Europe ◽  
Northern China ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Jet Stream ◽  
Cold Air ◽  
Weather Events

<p>The recent rapid warming of the Arctic atmosphere and ocean and related sea ice decline have been associated with increasing occurrence of extreme weather events in the Arctic. Applying ERA-Interim reanalysis, we identify 100 days with largest positive and negative anomalies (compared to local climatology) in 2-m air temperature (T2m) in the Northern Hemisphere in winter during 2005-2019, and address various physical mechanisms contributing to these events. The mechanisms responsible for warm extremes in the Arctic are often associated with a meandering Polar front jet stream, favouring cases of large transports of heat and moisture from mid-latitudes to the Arctic. In addition, subsidence heating often contributes to warm extremes in the Arctic, allowing them to occur also under high-pressure conditions. The coldest T2m anomalies north of 30<sup>o</sup>N mostly occur in regions that are also climatologically cold, i.e., cannot be strongly affected by cold-air advection. This suggests a dominating role local surface energy budget and boundary-layer processes.</p><p>Extreme weather events often interact with anomalies in sea ice concentration. Cases of strong winds transporting warm, moist air masses to the Arctic provide both dynamic and thermodynamic forcing for large sea ice anomalies, and during winter the openings in sea ice field contribute to air temperature extremes via large heat fluxes from the ocean to atmosphere.</p><p>Coldest winter extremes in mid-latitudes are typically associated with meandering jet stream and high-pressure blockings, but show differences between Central Europe, North America and northern China. In Central Europe the coldest events are typically associated with cold-air advection from the East or Northeast, whereas during the coldest events in North American East Coast the cold air is transported from the North. In northern China, the coldest events often occur under high-pressure conditions with weak winds. Accordingly, the role of cold-air advection is much smaller than in the case of the coldest events in North America.</p>

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