Brief communication: Lower-bound estimates for residence time of energy in the atmospheres of Venus, Mars and Titan

Abstract. The residence time of energy in a planetary atmosphere, τ, which was recently introduced and computed for the Earth's atmosphere (Osácar et al., 2020), is here extended to the atmospheres of Venus, Mars and Titan. τ is the timescale for the energy transport across the atmosphere. In the cases of Venus, Mars and Titan, these computations are lower bounds due to a lack of some energy data. If the analogy between τ and the solar Kelvin–Helmholtz scale is assumed, then τ would also be the time the atmosphere needs to return to equilibrium after a global thermal perturbation.

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Brief Communication: Residence Time of Energy in the Atmospheres of Venus, Earth, Mars and Titan

10.5194/npg-2020-49 ◽

2021 ◽

Author(s):

Javier Pelegrina ◽

Carlos Osácar ◽

Amalio Fernández-Pacheco

Keyword(s):

Lower Bounds ◽

Residence Time ◽

Time Scale ◽

Planetary Atmosphere ◽

Residence Times ◽

Thermal Perturbation ◽

Return To Equilibrium ◽

Energy Data ◽

Earth’S Atmosphere ◽

Earth's Atmosphere

Abstract. The concept of residence time of energy in a planetary atmosphere τR, recently introduced and computed for the Earth's atmosphere (Osácar et al., 2020), is here extended to the atmospheres of Venus, Mars and Titan. After a global thermal perturbation, τR is the time scale the atmosphere needs to return to equilibrium. The residence times of energy in the atmospheres of Venus, Earth, Mars and Titan have been computed. In the cases of Venus, Mars and Titan, these are mere lower bounds due to a lack of some energy data.

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Estudo das Rajadas de Vento no Semiárido Brasileiro

Ciência e Natura ◽

10.5902/2179460x45219 ◽

2020 ◽

Vol 42 ◽

pp. e3

Author(s):

Luana Dos Santos Ferreira ◽

Dimas De Barros Santiago ◽

Edson Matias dos Santos ◽

Renata Carvalho de Araújo ◽

Roberto Fernando da Fonseca Lyra

Keyword(s):

Renewable Energy ◽

Wind Speed ◽

Human Activity ◽

Air Temperature ◽

Energy Transport ◽

Daily Maximum ◽

Earth’S Atmosphere ◽

Earth's Atmosphere ◽

Time Of Year

To qualify the wind it is necessary to know its direction and speed. It may have interference in direction and wind speed location, time of year, air temperature, pressure of the earth's atmosphere, humidity, atmosphere and reliefs. Their knowledge is of essential importance in various sectors of human activity, including aircraft safety, navigation, civil construction, agriculture, renewable energy, transport and etc. The focus of this work is the gusts of wind recorded in different regions of the semiarid state of Alagoas (Arapiraca and Palmeira dos Índios) and Pernambuco (Garanhuns and Petrolina) in the period 2014-2018. were analyzed the seasonal direction of the gusts, mean annual speed and gust distributions (seasonal and daily), Maximum annual bursts, monthly gust distributions, occurrences above 15 m/s and the day of the highest gust on the surface, to observe how behaves the gusts, temperature, pressure and direction at the time of winds peak.

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The Problem of Kinetic Heating Associated with Unmanned Re-entry Vehicles

Journal of the Royal Aeronautical Society ◽

10.1017/s036839310007783x ◽

1962 ◽

Vol 66 (624) ◽

pp. 764-766

Author(s):

A. J. Craig

Keyword(s):

Dynamic Stability ◽

Planetary Atmosphere ◽

List Type ◽

Mechanical Shock ◽

Art And Science ◽

Earth’S Atmosphere ◽

Earth's Atmosphere

The art and science of re-entering a vehicle into a planetary atmosphere poses many problems, which are today on the edge of man’s mental and industrial capabilities. Re-entering a vehicle into the earth’s atmosphere incurs the following major problems: —(a) Kinetic heating as it passes through the denser regions of the atmosphere. Materials have to be found which can deal with the enormous amounts of heating experienced by the vehicle.(b) Design of a vehicle to withstand large thermal and mechanical shock.(c) Dynamic stability at hypersonic velocities.(d) Accuracy of direction of entry into the atmosphere.(e) Recovery of the capsule after impact, wherever it landed.This paper deals with the kinetic heating aspect of re-entry and shows how present day materials are utilised in restricting the inside temperature of re-entry vehicles to within reasonable limits. Unmanned re-entry is specified because to re-enter a manned capsule puts large restrictions on deceleration and inside temperature limits and hence produces some unique problems which are not covered in this paper.

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