scholarly journals Using the Polar Jet Stream Core Wind Speed to Estimate the Surface Low Pressure System value during winter

2019 ◽  
Vol 30 (1) ◽  
pp. 7
Author(s):  
Hazim D. Mohsin
Keyword(s):  
Low Pressure ◽  
Jet Stream ◽  
Pressure System ◽  
High Frequencies ◽  
The Core ◽  
Linear Regression Technique ◽  
Good Element ◽  
Low Pressure System ◽  
Indirect Relationship ◽  
The Relationship

The work studied the relationship between polar jet stream core speed at 300 hPa level and the surface low pressure system on winter seasons during years from 2014 to 2016. Februaries were chosen from winter seasons which the polar jet stream passes with high frequencies over the area of study. The study presented that the structure of polar jet was almost continuous jet-type structure that the jet core was easy to recognize and it had indirect relationship with the low pressure systems at surface. the Pearson's (R) statistical test used to show the strength of that relationship which accessible values were between (0.6 - 1) that presented the core speed values as a good element to derive equation connecting between the low pressure system value in (hPa) at surface and core speed value in (kt) at 300 hPa level . The simple linear regression technique is used to drive the equation that connects between the low pressure system and the jet core speed value which was (Low pressure center value (hPa) =1042.57 ̶ (0.307 × core speed (kt) )) . The equation was tested against some jet stream cases at 300 hPa that were the highest value of the jet core speed, the lowest and middle selected value which presented the percentage errors were between (0.03-0.09). the chart analyzing presented the lowest low pressure system center corresponded the highest the jet core speed values as shown in 11 Feb., 2015 at 00 UTC which the core speed was 150 (kt) corresponding the surface low pressure system which was 993 (hPa)

scholarly journals The Relationship between Disturbance of the Polar Jet Stream and the Surface Low Pressure Intensity

2019 ◽  
Vol 30 (2) ◽  
pp. 1
Author(s):  
Hazim D. Mohsin ◽  
Monim H. Al-Jiboori ◽  
Asraa Khtan
Keyword(s):  
Geopotential Height ◽  
Direct Relationship ◽  
Low Pressure ◽  
High Ratio ◽  
Jet Stream ◽  
Pressure Center ◽  
Pressure System ◽  
Low Pressure System ◽  
Indirect Relationship ◽  
The Relationship

The work studied the relationship between polar jet stream and surface low pressure in April's months during years from 2014 to 2016 which the polar jet passes with high frequencies over the area of study. The study presents the structure of polar jet that affects significantly in the intensity of the low pressure system at the surface. The structuredid not repeat regularly during April's months for the years from 2014 to 2016 and it was two structures, continuous and discontinuous with different percentage ratios from a year to year. The percentages ratios of discontinuous jet-types were in2014 about 36 %, 6 % in 2015, 92 % in 2016 which declared to estimate low pressure center value on the surface which need the corrected recognizing the polar jet-type depending on its structure. The relationship between low pressure center value and the lowest polar jet geopotential height was during April 2014 which was generally direct relationship with continuous jet-type while it was indirect relationship with discontinuous jet-type. The mixing continuous and discontinuous jet-types data in same year will distorted that relationship. The discontinuous jet-type structure was significant to limit the relationship between low pressure center on surface and geopotential height which was direct relationship with small ratio of discontinuous as April 2015 jet-type and high ratio as April 2016 while with ratio near from middle as April 2014 relationship was distorted. The study also revealed the low pressure center value would be less withthe discontinuous jet-type if there were same geopotential height values of continuous and discontinuous jet-type

Estimation of Design Parameters and Performance for a State-of-the-Art Turbofan

2021 ◽  
Author(s):  
Oliver Sjögren ◽  
Carlos Xisto ◽  
Tomas Grönstedt
Keyword(s):  
Performance Metrics ◽  
State Of The Art ◽  
Low Pressure ◽  
Performance Model ◽  
Cycle Performance ◽  
Civil Aviation ◽  
Design Parameters ◽  
Pressure System ◽  
Public Data ◽  
Low Pressure System

Abstract The aim of this study is to explore the possibility of matching a cycle performance model to public data on a state-of-the-art commercial aircraft engine (GEnx-1B). The study is focused on obtaining valuable information on figure of merits for the technology level of the low-pressure system and associated uncertainties. It is therefore directed more specifically towards the fan and low-pressure turbine efficiencies, the Mach number at the fan-face, the distribution of power between the core and the bypass stream as well as the fan pressure ratio. Available cycle performance data have been extracted from the engine emission databank provided by the International Civil Aviation Organization (ICAO), type certificate datasheets from the European Union Aviation Safety Agency (EASA) and the Federal Aviation Administration (FAA), as well as publicly available data from engine manufacturer. Uncertainties in the available source data are estimated and randomly sampled to generate inputs for a model matching procedure. The results show that fuel performance can be estimated with some degree of confidence. However, the study also indicates that a high degree of uncertainty is expected in the prediction of key low-pressure system performance metrics, when relying solely on publicly available data. This outcome highlights the importance of statistic-based methods as a support tool for the inverse design procedures. It also provides a better understanding on the limitations of conventional thermodynamic matching procedures, and the need to complement with methods that take into account conceptual design, cost and fuel burn.

The effect of vasoactive drugs on the low-pressure system

1978 ◽  
Vol 73 (2) ◽  
pp. 220-229 ◽  
Author(s):  
K. Kirsch ◽  
A. Ameln ◽  
H. J. Wicke
Keyword(s):  
Low Pressure ◽  
Vasoactive Drugs ◽  
Pressure System ◽  
Low Pressure System

scholarly journals Synoptic perspectives on pollutant transport patterns observed by satellites over East Asia: Case studies with a conceptual model

2016 ◽  
Author(s):  
Hyun Cheol Kim ◽  
Soontae Kim ◽  
Seok-Woo Son ◽  
Pius Lee ◽  
Chun-Sil Jin ◽  
...  
Keyword(s):  
High Pressure ◽  
East Asia ◽  
Southern China ◽  
Low Pressure ◽  
Pressure System ◽  
Weather Patterns ◽  
High Pressure System ◽  
Synoptic Weather ◽  
Low Pressure System ◽  
Transport Patterns

Abstract. We demonstrate that daily pollutant transport patterns in East Asia are visible from satellite images when inspected with corresponding synoptic weather analyses. Transport pathways of air pollutants in East Asia are investigated using satellite observations, surface weather charts, and chemical-transport model simulations. It is found that during cool season (fall to spring), pollutant transports in East Asia are largely determined by synoptic weather patterns associated with high pressure system over southern China, which is extended from the Siberia High, and low pressure system over Manchuria, which is initiated by Altai-Sayan cyclogenesis. Based on the relative location and strength of these weather systems, three types of synoptic weather patterns that may contribute to pollutants transport in East Asia, especially in China and Korea, are identified: i.e., (1) a strengthening of the Siberian High and its southeastward propagation; (2) a high-pressure system over southern China followed by a frontal passage associated with a northern low-pressure system; and (3) a stagnant high-pressure system over southern China. For all three patterns, the high-pressure system in southern China is essential for the development of regional air pollution, while frontal activities associated with low-pressure system provide a forcing mechanism to transport those pollutants eastward or southeastward. Observed and simulated surface PM distributions show good agreement in both aerosol optical depth and NO2 column density further implying that anthropogenic emissions also contribute to regional events of high surface PM concentrations. It is argued that the quasi-periodic migration of synoptic weather systems in East Asia works as an efficient pump of pollutants; i.e., regional air pollutions developed under high-pressure systems are transported downstream by low-pressure systems.

Synoptic and Mesoscale Background of the Disastrous Heavy Rainfall in Sri Lanka Caused by a Low Pressure System

2021 ◽  
pp. 407-416
Author(s):  
A. R. P. Warnasooriya ◽  
K. H. M. S. Premalal ◽  
A. W. S. J. Kumara ◽  
Chathuska G. Premachandra
Keyword(s):  
Sri Lanka ◽  
Heavy Rainfall ◽  
Low Pressure ◽  
Pressure System ◽  
Low Pressure System
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