Determination of Air Density at High Altitude by Means of an Earth Satellite

1957 ◽  
Vol 25 (2) ◽  
pp. 115-115 ◽  
Author(s):  
G. Leitmann
Keyword(s):  
High Altitude ◽  
Earth Satellite ◽  
Air Density

The Optical Measurement of Lapse Rate *

1950 ◽  
Vol 31 (2) ◽  
pp. 51-55 ◽  
Author(s):  
Robert G. Fleagle
Keyword(s):  
Optical Measurement ◽  
Vertical Gradient ◽  
Lapse Rate ◽  
Speed Of Light ◽  
Indirect Methods ◽  
Reliable Determination ◽  
Air Density ◽  
Lapse Rates ◽  
The Relationship

The need for reliable determination of the temperature of the air very near the ground and the difficulties inherent in measurement of this quantity by the ordinary indirect methods are pointed out. It is suggested that the dependence of the speed of light on air density provides a convenient method for the determination of the temperature near the ground by direct measurement of the lapse rate, and evidence is given from other papers to show that this is feasible where the vertical gradient of humidity is not great. The relationship between apparent elevation and lapse rates of temperature and vapor pressure is derived, and the relationship is illustrated by the results of computations.

scholarly journals New High-Altitude Study of Cosmic-Ray Bands and a New Determination of Their Total Energy Content

1933 ◽  
Vol 44 (4) ◽  
pp. 246-252 ◽  
Author(s):  
I. S. Bowen ◽  
R. A. Millikan ◽  
H. V. Neher
Keyword(s):  
Total Energy ◽  
High Altitude ◽  
Energy Content ◽  
Cosmic Ray ◽  
Total Energy Content

Accurate determination of the total alkalinity and the CO2 system parameters in high-altitude lakes from the Western Pyrenees (France – Spain)

2020 ◽  
Vol 152 ◽  
pp. 104345
Author(s):  
Leire Kortazar ◽  
Bastien Duval ◽  
Olaia Liñero ◽  
Olaia Olamendi ◽  
Ainhoa Angulo ◽  
...  
Keyword(s):  
High Altitude ◽  
Accurate Determination ◽  
Total Alkalinity ◽  
System Parameters ◽  
High Altitude Lakes ◽  
Western Pyrenees

scholarly journals Efficiency of High Altitude On-shore Wind Turbines: Air Density and Turbulence Effects—Qollpana Wind Farm (Bolivia)

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 487 ◽  
Author(s):  
Rober Mamani ◽  
Norbert Hackenberg ◽  
Patrick Hendrick
Keyword(s):  
High Altitude ◽  
Wind Turbines ◽  
Wind Farm ◽  
Air Density ◽  
Turbulence Effects

Influence of Altitude on the Performance of a Bicycle-Cyclist Set

2017 ◽  
Author(s):  
Mateo Morales ◽  
Sergio D. Roa ◽  
Luis E. Muñoz ◽  
Diego A. Ferreira ◽  
Omar D. Lopez Mejia
Keyword(s):  
High Altitude ◽  
Drag Force ◽  
Power Output ◽  
Aerodynamic Drag ◽  
Integrated Approach ◽  
Cycling Performance ◽  
Air Density ◽  
Effort Tests ◽  
Different Altitudes

There is a tradeoff between power delivery and aerodynamic drag force when cyclists ride at different altitudes. The result is particular to the characteristics of the bicycle as well as the aerobic fitness of the cyclist. This work proposes a methodology based on an integrated approach to the study of the influence of altitude on power output and aerodynamic drag over a particular bicycle-cyclist set. The methodology consists of an independent analysis for each of the effects, to conclude with an integration of results that allows estimating the overall effect of altitude on cycling performance. A case study for the application of the methodology was developed, and the obtained results apply for the specific bicycle-cyclist set under analysis. First, the relationship between power and time was analyzed for a male recreational cyclist based on all-out effort tests at two different altitudes: 237 meters and 2652 meters above sea level (m.a.s.l). Second, the effects of environmental conditions on air density and drag area coefficient due to altitude changes were analyzed based on Computational Fluid Dynamics (CFD) simulations. It was found that for the bicycle-cyclist set under study, the sustainable power output for 1-hour cycling was reduced 45W for the high-altitude condition as a consequence of the reduction in the maximum oxygen uptake capacity. In addition, the aerodynamic drag force is reduced in greater proportion due to the change in air density than due to the change in drag coefficient. Finally, the results of both effects were integrated to analyze the overall influence of altitude on cycling performance. It was found that for the analyzed case study, the aerodynamic advantage at higher altitude dominates over the disadvantage of reduction in power output: despite delivering 45W less, the subject can travel an additional distance of 900 meters during a one hour ride for the high-altitude condition compared to that in low altitude.

scholarly journals Scientific Need for Space Astronomy

1980 ◽  
Vol 5 ◽  
pp. 63-68
Author(s):  
L. Goldberg
Keyword(s):  
High Altitude ◽  
Phase 1 ◽  
Satellite Orbit ◽  
Earth Satellite ◽  
Second Phase ◽  
National Academy Of Sciences ◽  
Space Astronomy ◽  
Small Satellites ◽  
Time Space ◽  
Two Phases

Many scientific justifications for space astronomy have been prepared by individuals and committees during the past three decades or more. The first such report that I am aware of, called “Astronomical Advantages of an Extraterrestrial Observatory”, was written by Lyman Spitzer in September 1946, and although its goals were extremely modest by today’s standards, the report did dwell with enthusiasm on the ultimate goal of a large reflecting telescope 4-6 meters in diameter with diffraction-limited optics put into earth-satellite orbit. The latest study, from which I shall quote liberally, has just been published by the Astronomy Committee of the U. S. National Academy of Sciences, and provides the scientific foundation for space astronomy in the 1980’s. Space Astronomy was initiated about one month after the date of publication of Spitzer’s report, when the first high-altitude rocket was launched to observe the sun’s ultraviolet radiation. Since that time, space astronomy has completed two phases and is about to embark on a third. In Phase 1, which lasted until the beginning of Sputnik, observations were made for a few minutes at a time from high-altitude rockets. In the second phase, which is just ending, observations were made with relatively small instruments in earth-orbiting satellites. The observing programs carried out with rockets and small satellites were called experiments because their capabilities and objectives were limited and their lifetimes were short -from a few minutes to about a year.

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