scholarly journals Propagation of radiosonde pressure sensor errors to ozonesonde measurements

2014 ◽  
Vol 7 (1) ◽  
pp. 65-79 ◽  
Author(s):  
R. M. Stauffer ◽  
G. A. Morris ◽  
A. M. Thompson ◽  
E. Joseph ◽  
G. J. R. Coetzee ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Atmospheric Pressure ◽  
Pressure Profile ◽  
Mixing Ratio ◽  
Concentration Cell ◽  
Pressure Profiles ◽  
Dependent Variables ◽  
Sensor Errors ◽  
Subsequent Addition ◽  
Total Column

Abstract. Several previous studies highlight pressure (or equivalently, pressure altitude) discrepancies between the radiosonde pressure sensor and that derived from a GPS flown with the radiosonde. The offsets vary during the ascent both in absolute and percent pressure differences. To investigate this problem further, a total of 731 radiosonde/ozonesonde launches from the Southern Hemisphere subtropics to northern mid-latitudes are considered, with launches between 2005 and 2013 from both longer term and campaign-based intensive stations. Five series of radiosondes from two manufacturers (International Met Systems: iMet, iMet-P, iMet-S, and Vaisala: RS80-15N and RS92-SGP) are analyzed to determine the magnitude of the pressure offset. Additionally, electrochemical concentration cell (ECC) ozonesondes from three manufacturers (Science Pump Corporation; SPC and ENSCI/Droplet Measurement Technologies; DMT) are analyzed to quantify the effects these offsets have on the calculation of ECC ozone (O3) mixing ratio profiles (O3MR) from the ozonesonde-measured partial pressure. Approximately half of all offsets are > ±0.6 hPa in the free troposphere, with nearly a third > ±1.0 hPa at 26 km, where the 1.0 hPa error represents ~ 5% of the total atmospheric pressure. Pressure offsets have negligible effects on O3MR below 20 km (96% of launches lie within ±5% O3MR error at 20 km). Ozone mixing ratio errors above 10 hPa (~ 30 km), can approach greater than ±10% (> 25% of launches that reach 30 km exceed this threshold). These errors cause disagreement between the integrated ozonesonde-only column O3 from the GPS and radiosonde pressure profile by an average of +6.5 DU. Comparisons of total column O3 between the GPS and radiosonde pressure profiles yield average differences of +1.1 DU when the O3 is integrated to burst with addition of the McPeters and Labow (2012) above-burst O3 column climatology. Total column differences are reduced to an average of −0.5 DU when the O3 profile is integrated to 10 hPa with subsequent addition of the O3 climatology above 10 hPa. The RS92 radiosondes are superior in performance compared to other radiosondes, with average 26 km errors of −0.12 hPa or +0.61% O3MR error. iMet-P radiosondes had average 26 km errors of −1.95 hPa or +8.75 % O3MR error. Based on our analysis, we suggest that ozonesondes always be coupled with a GPS-enabled radiosonde and that pressure-dependent variables, such as O3MR, be recalculated/reprocessed using the GPS-measured altitude, especially when 26 km pressure offsets exceed ±1.0 hPa/±5%.

scholarly journals Propagation of radiosonde pressure sensor errors to ozonesonde measurements

2013 ◽  
Vol 6 (4) ◽  
pp. 7771-7810 ◽  
Author(s):  
R. M. Stauffer ◽  
G. A. Morris ◽  
A. M. Thompson ◽  
E. Joseph ◽  
G. J. R. Coetzee
Keyword(s):  
Pressure Sensor ◽  
Atmospheric Pressure ◽  
Mixing Ratio ◽  
Concentration Cell ◽  
Dependent Variables ◽  
Sensor Errors ◽  
Subsequent Addition ◽  
Total Column ◽  
Pressure Altitude

Abstract. Several previous studies highlight pressure (or equivalently, pressure altitude) discrepancies between the radiosonde pressure sensor and that derived from a GPS flown with the radiosonde. The offsets vary during the ascent both in absolute and percent pressure differences. To investigate this, a total of 501 radiosonde/ozonesonde launches from the Southern Hemisphere subtropics to northern mid-latitudes are considered, with launches between 2006–2013 from both historical and campaign-based intensive stations. Three types of electrochemical concentration cell (ECC) ozonesonde manufacturers (Science Pump Corporation; SPC and ENSCI/Droplet Measurement Technologies; DMT) and five series of radiosondes from two manufacturers (International Met Systems: iMet, iMet-P, iMet-S, and Vaisala: RS80 and RS92) are analyzed to determine the magnitude of the pressure offset and the effects these offsets have on the calculation of ECC ozone (O3) mixing ratio profiles (O3MR) from the ozonesonde-measured partial pressure. Approximately half of all offsets are > ±0.7 hPa in the free troposphere, with nearly a quarter > ±1.0 hPa at 26 km, where the 1.0 hPa error represents ~5% of the total atmospheric pressure. Pressure offsets have negligible effects on O3MR below 20 km (98% of launches lie within ±5% O3MR error at 20 km). Ozone mixing ratio errors in the 7–15 hPa layer (29–32 km), a region critical for detection of long-term O3 trends, can approach greater than ±10% (>25% of launches that reach 30 km exceed this threshold). Comparisons of total column O3 yield average differences of +1.6 DU (−1.1 to +4.9 DU 10th to 90th percentiles) when the O3 is integrated to burst with addition of the McPeters and Labow (2012) above-burst O3 column climatology. Total column differences are reduced to an average of +0.1 DU (−1.1 to +2.2 DU) when the O3 profile is integrated to 10 hPa with subsequent addition of the O3 climatology above 10 hPa. The RS92 radiosondes are clearly distinguishable in performance from other radiosondes, with average 26 km errors of +0.32 hPa (−0.09 to +0.54 hPa 10th to 90th percentiles) or −1.31% (−2.19 to +0.37%) O3MR error. Conversely, iMet-P radiosondes had average 26 km errors of −1.49 hPa (−2.33 to −0.82 hPa) or +6.71% (+3.61 to +11.0%) O3MR error. Based on our analysis, we suggest that ozonesondes always be coupled with a GPS-enabled radiosonde and that pressure-dependent variables, such as O3MR, be recalculated/reprocessed using the GPS-measured altitude, particularly when 26 km pressure offsets exceed ±1.0 hPa/±5%.

scholarly journals Zernike polynomials applied to apparent solar disk flattening for pressure profile retrievals

2013 ◽  
Vol 6 (3) ◽  
pp. 823-835 ◽  
Author(s):  
E. Dekemper ◽  
F. Vanhellemont ◽  
N. Mateshvili ◽  
G. Franssens ◽  
D. Pieroux ◽  
...  
Keyword(s):  
Transfer Matrix ◽  
Atmospheric Pressure ◽  
Solar Disk ◽  
Pressure Profile ◽  
Training Dataset ◽  
Zernike Polynomials ◽  
Test Cases ◽  
Inversion Algorithm ◽  
Pressure Profiles ◽  
Limb Darkening

Abstract. We present a passive method for the retrieval of atmospheric pressure profiles based on the measurement of the apparent flattening of the solar disk as observed through the atmosphere by a spaceborne imager. This method was applied to simulated sunsets. It relies on accurate representation of the solar disk, including its limb darkening, and how its image is affected by atmospheric refraction. The Zernike polynomials are used to quantify the flattening in the Sun images. The inversion algorithm relies on a transfer matrix providing the link between the atmospheric pressure profile and a sequence of Zernike moments computed on the sunset frames. The transfer matrix is determined by a training dataset of pressure profiles generated from a standard climatology. The performance and limitations of the method are assessed by two test cases. Pressure profiles similar to the training dataset show that retrieval error can be up to 10 times smaller than the natural variability in the lower mesosphere, and up to 500 times smaller in the upper troposphere. Tests with other independent profiles emphasize the need for better representativeness of the training dataset.

scholarly journals Zernike polynomials applied to apparent solar disk flattening for pressure profile retrievals

2012 ◽  
Vol 5 (5) ◽  
pp. 7535-7565
Author(s):  
E. Dekemper ◽  
F. Vanhellemont ◽  
N. Mateshvili ◽  
G. Franssens ◽  
D. Pieroux ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Solar Disk ◽  
Pressure Profile ◽  
Natural Variability ◽  
Zernike Moments ◽  
Zernike Polynomials ◽  
Passive Method ◽  
Solar Occultation ◽  
Pressure Profiles

Abstract. We present a passive method for the retrieval of atmospheric pressure profiles based on the measurement of the apparent flattening of the solar disk as observed through the atmosphere by a spaceborne imager. It involves accurate simulations of the solar occultation and uses the Zernike moments to quantify the flattening. This method is expected to achieve retrievals up to the lower mesosphere with uncertainties 10 to 1000 times smaller than the natural variability.

Patterns and Reduced-order Reconstruction of Impinging Wiping Jet Pressure Profile Fluctuation Using Proper Orthogonal Decomposition

2021 ◽  
Author(s):  
Le Quang Phan ◽  
Andrew Johnstone ◽  
P. Buyung Kosasih ◽  
Wayne Renshaw
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Jet Impingement ◽  
Pressure Profile ◽  
Orthogonal Decomposition ◽  
Maximum Pressure ◽  
Frequency Spectra ◽  
Reduced Order ◽  
Order Reconstruction ◽  
Pressure Profiles ◽  
Proper Orthogonal

Abstract Wiping jet impingement pressure is important in controlling the coating mass (thickness) and influencing the smoothness of the thin metallic coating produced in continuous galvanizing lines (CGLs). However, the fluctuation of the impingement pressure profile that directly impacts the coating smoothness has not been adequately understood. To study key features of the impingement pressure fluctuation, the instantaneous impingement pressure profiles obtained from Large Eddy Simulations were analyzed using Proper Orthogonal Decomposition (POD). Dominant fluctuation modes of pressure profiles can be differentiated from the energy contents of the modes corresponding to different jet types namely mixing, non-mixing, and transitional mixing jet. The dominant modes of mixing jets in the wiping region contain comparable strength of all modes (flapping, pulsing, and out-of-phase multi pulsing). Non-mixing jets do not show discernable fluctuation modes and transitional mixing jets show pulsing and flapping modes only. Additionally, instantaneous maximum pressure gradient and their location were determined from the reduced-order reconstruction of the pressure profiles. From the analysis, frequency spectra of the magnitude and location fluctuations of the maximum pressure gradients associated with each of the jet types can be clearly distinguished. This is a knowledge that may be helpful for CGL operators in the operation of wiping jets.

The Effects of Oil Supply Pressure at different Groove Position on Temperature and Pressure Profile in Journal Bearing

2013 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
R. S. Dwyer-Joyce ◽  
Aidah Jumahat
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Diameter Ratio ◽  
Radial Load ◽  
Oil Supply ◽  
Supply Pressure ◽  
Pressure Profiles ◽  
Hydrodynamic Journal Bearing ◽  
Temperature And Pressure ◽  
Length To Diameter Ratio

The effects of oil supply pressure on the temperature and pressure at different groove locations on a hydrodynamic journal bearing were investigated. A journal with a diameter of 100 mm and a ½ length-to-diameter ratio was used. The supply pressure was set to 0.2, 0.5, and 0.7 MPa at seven different groove locations, namely, -45°, -30°, -15°, 0°, +15°, +30°, and +45°. Temperature and pressure profiles were measured at speed values of 300, 500, and 800 rpm with 10 kN radial load. The results show that the change in oil supply pressure simultaneously reduced the temperature and increased the pressure profile.

scholarly journals BLOOD PRESSURE PROFILES AMONG EAST BONGAS AND WEST BONGAS PEOPLE IN EFFORT AND SUPPORT FROM UNIVERSITAS PADJADJARAN AND THE REGENT OF MAJALENGKA REGENCY AND CHIEVES OF THE VILLAGES

2017 ◽  
Vol 9 (6) ◽  
pp. 215
Author(s):  
Diah Dhianawaty D. ◽  
Henhen Heryaman ◽  
Mas Rizky Anggun Adipurna Syamsunarno
Keyword(s):  
Blood Pressure ◽  
Age Groups ◽  
Simple Random Sampling ◽  
Pressure Profile ◽  
Joint National Committee ◽  
National Committee ◽  
Cross Sectional ◽  
Male And Female ◽  
The People ◽  
Pressure Profiles

Objective: To support the people in East Bongas and West Bongas villages to prevent and treatment the hypertension disease.Methods: This was a cross-sectional design while the subjects were taken by a simple random sampling. A total of 323 families were included, and blood pressure of the male and female subjects aged between 18 to 65 y was measured and had been given a question relating to their blood pressure.Results: The blood pressure profile was classified based on the seventh report of the Joint National Committee (JNC 7). The youngest male and female participants of pre-hypertension were 18 and 22 y, respectively. The normal blood pressure, pre-hypertension, hypertension stage-1, and hypertension stage-2 were 34.3%, 49.5%, 12.1%, and 4.1%, respectively. Prevalence of patients with hypertension based on the age groups 30-39, 40-49, 50-59, and 60-69 y were 6.8%, 15.6%, 33.9%, and 37.3%, respectively. Prevalence of patients with hypertension in male was 16.8%, the female was 15.7%, and the total of both were 16.2%. Prevalence based on gender showed that those who had information about hypertension in male was 46.8%, the female was 47.9%, and the total of both were 47.4%. Prevalence of hypertension patients increased, for a male was 8.9%, the female was 8.2%, and the total of both were 8.5% after the participants declared that they were not hypertension patients.Conclusion: In both villages occurred an increase of hypertension prevalence. Based on this information, the people in two villages should be given the appropriate knowledge and awareness regarding hypertension.

scholarly journals Modeling the Response of Magnetorheological Fluid Dampers under Seismic Conditions

2019 ◽  
Vol 9 (19) ◽  
pp. 4189 ◽  
Author(s):  
Darson Dezheng Li ◽  
Declan Finn Keogh ◽  
Kevin Huang ◽  
Qing Nian Chan ◽  
Anthony Chun Yin Yuen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Pressure Drop ◽  
Fluid Velocity ◽  
Pressure Profile ◽  
Inlet Pressure ◽  
Mr Fluid ◽  
Pressure Profiles ◽  
Efficiency And Effectiveness ◽  
Fluid Dampers ◽  
Mr Fluid Damper

Magnetorheological (MR) fluid is a smart material fabricated by mixing magnetic-responsive particles with non-magnetic-responsive carrier fluids. MR fluid dampers are able to provide rapid and reversible changes to their damping coefficient. To optimize the efficiency and effectiveness of such devices, a computational model is developed and presented where the flow field is simulated using the computational fluid dynamics approach, coupled with the magnetohydrodynamics model. Three different inlet pressure profiles were designed to replicate real loading conditions are examined, namely a constant pressure, a sinusoidal pressure profile, and a pressure profile mimicking the 1994 Northbridge earthquake. When the MR fluid damper was in its off-state, a linear pressure drop between the inlet and the outlet was observed. When a uniform perpendicular external magnetic field was applied to the annular orifice of the MR damper, a significantly larger pressure drop was observed across the annular orifice for all three inlet pressure profiles. It was shown that the fluid velocity within the magnetized annular orifice decreased proportionally with respect to the strength of the applied magnetic field until saturation was reached. Therefore, it was clearly demonstrated that the present model was capable of accurately capturing the damping characteristics of MR fluid dampers.

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