Search Results
You are looking at 1 - 3 of 3 items for
- Author or Editor: W. E. McGovern x
- Refine by Access: All Content x
Abstract
When radiative transfer is the dominant mechanism cooling the lower thermosphere of Jupiter, CH4, (7.7μ) is probably the dominant cooling agent; however, its low turbopause mixing ratio (10−4, as compared to 10−3 in the lower atmosphere) contributes to a cooling rate small (≲10−4) compared to CO2 on Mars. This results in a Javian mesopause density ∼10 times the Martian density or ∼1014 cm−3, if radiative cooling is the primary heat transfer mechanism in the lower thermosphere. An alternate method for transporting heat is convection (forced or free), which apparently emerges as the dominant transport mechanism as the effective eddy diffusion coefficient (Kv ) approaches values similar to those anticipated in the earth's lower thermosphere (106 cm see−1). Over the solar cycle, with a high heating efficiency (0.86), the temperature rise above the turbopause ranges between 19 and 53K for weak convective activity (Kv =105 cm see−1) and 7–19K for strong activity (107 cm see−1), suggesting that satellite measurements of the exospheric temperature could be used to estimate the degree of convective activity present in the upper atmosphere. Reasonable variations in the H2-He ratio and the mesopause height (∼300 km), temperature (140K) and cooling rate are of minor importance compared to the heating efficiency and the incident flux in establishing the thermospheric temperature profile via the heat conduction equation. The diurnal temperature variation in the Jovian exosphere over the solar cycle is small, probably less than 5–10K.
Abstract
When radiative transfer is the dominant mechanism cooling the lower thermosphere of Jupiter, CH4, (7.7μ) is probably the dominant cooling agent; however, its low turbopause mixing ratio (10−4, as compared to 10−3 in the lower atmosphere) contributes to a cooling rate small (≲10−4) compared to CO2 on Mars. This results in a Javian mesopause density ∼10 times the Martian density or ∼1014 cm−3, if radiative cooling is the primary heat transfer mechanism in the lower thermosphere. An alternate method for transporting heat is convection (forced or free), which apparently emerges as the dominant transport mechanism as the effective eddy diffusion coefficient (Kv ) approaches values similar to those anticipated in the earth's lower thermosphere (106 cm see−1). Over the solar cycle, with a high heating efficiency (0.86), the temperature rise above the turbopause ranges between 19 and 53K for weak convective activity (Kv =105 cm see−1) and 7–19K for strong activity (107 cm see−1), suggesting that satellite measurements of the exospheric temperature could be used to estimate the degree of convective activity present in the upper atmosphere. Reasonable variations in the H2-He ratio and the mesopause height (∼300 km), temperature (140K) and cooling rate are of minor importance compared to the heating efficiency and the incident flux in establishing the thermospheric temperature profile via the heat conduction equation. The diurnal temperature variation in the Jovian exosphere over the solar cycle is small, probably less than 5–10K.
An unprecedented analysis of the atmosphere of planet Earth is currently underway with the involvement of over 140 countries in the Global Weather Experiment—the largest international scientific experiment yet attempted. After many years of planning, the Operational Year began in December of 1978. Following the field phase and data management phase, a multi-year evaluation and research program will commence and continue until the late 1980s. During this period, scientists and technicians will examine the atmosphere, the sea surface, and the upper layer of the world's oceans in the most intense survey and study ever made. A number of successes and failures occurred in preparing for the observing phase and these are mentioned as each observing system actually deployed in the field is reviewed. The focus of the paper is on the quantity of data gathered and how it was obtained. The article concludes with some suggestions for assurances of final success of the Experiment.
An unprecedented analysis of the atmosphere of planet Earth is currently underway with the involvement of over 140 countries in the Global Weather Experiment—the largest international scientific experiment yet attempted. After many years of planning, the Operational Year began in December of 1978. Following the field phase and data management phase, a multi-year evaluation and research program will commence and continue until the late 1980s. During this period, scientists and technicians will examine the atmosphere, the sea surface, and the upper layer of the world's oceans in the most intense survey and study ever made. A number of successes and failures occurred in preparing for the observing phase and these are mentioned as each observing system actually deployed in the field is reviewed. The focus of the paper is on the quantity of data gathered and how it was obtained. The article concludes with some suggestions for assurances of final success of the Experiment.
During the Second Special Observing Period of May and June 1979, the Global Weather Experiment reached a peak. At this time the largest concentration of resources ever assembled was deployed to meet the challenge of observing the atmosphere and oceans to an unprecedented degree. This article outlines this effort and highlights the various observing systems involved in this effort—in particular the quantity of observations gathered from each major system.
During the Second Special Observing Period of May and June 1979, the Global Weather Experiment reached a peak. At this time the largest concentration of resources ever assembled was deployed to meet the challenge of observing the atmosphere and oceans to an unprecedented degree. This article outlines this effort and highlights the various observing systems involved in this effort—in particular the quantity of observations gathered from each major system.
