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- Author or Editor: Gerald R. Smith x
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Abstract
A theoretical study is made to assess the importance of the solar EUV flux in the thermal energy balance of the Jovian thermosphere. A global averaged vertical temperature contrast in the thermosphere of 15K is calculated and the mesopause is located at a particle density of 5×1013 cm−3. Thus, the upper atmosphere of Jupiter is approximately isothermal. At the mesopause IR cooling by C3H2 is an order of magnitude more important than IR cooling by CH4. Only the location of the mesopause is a sensitive function of the IR cooling agent in the upper atmosphere. The exospheric temperature depends principally on the mesopause temperature and the solar flux. Eddy heat transport plays a negligible role in the thermal energy balance of the Jovian thermosphere. For the thermospheres of Saturn and Titan the global averaged vertical temperature contrasts are estimated to be ∼10K and 90K, respectively, if their compositions are similar to Jupiter's and the same physics is applicable.
Abstract
A theoretical study is made to assess the importance of the solar EUV flux in the thermal energy balance of the Jovian thermosphere. A global averaged vertical temperature contrast in the thermosphere of 15K is calculated and the mesopause is located at a particle density of 5×1013 cm−3. Thus, the upper atmosphere of Jupiter is approximately isothermal. At the mesopause IR cooling by C3H2 is an order of magnitude more important than IR cooling by CH4. Only the location of the mesopause is a sensitive function of the IR cooling agent in the upper atmosphere. The exospheric temperature depends principally on the mesopause temperature and the solar flux. Eddy heat transport plays a negligible role in the thermal energy balance of the Jovian thermosphere. For the thermospheres of Saturn and Titan the global averaged vertical temperature contrasts are estimated to be ∼10K and 90K, respectively, if their compositions are similar to Jupiter's and the same physics is applicable.
Abstract
We provide morphological and kinematic desc6ptions of the UV markings seen in the Mariner 10 imagery of Venus: the dark horizontal Y, bow-like waves, circumequatorial belts, subsolar disturbance, spiral streaks and bands, polar ring and polar region. The dark horizontal Y is interpreted as a westward-propagating planetary wave with zonal wavenumber 1 and period ∼4.2 days; it may he the superposition of a Rossby-Haurwitz wave dominant at mid-latitudes and a Kelvin wave dominant in equatorial regions. Bow-like waves may be true bow waves formed by the interaction of the rapid zonal flow with internal gravity waves of lower horizontal phase speeds generated by the subsolar disturbance. Circumequatorial belts are interpreted as internal gravity waves with horizontal wavelength ∼500 km and zonal extent ∼5000 km. They are essentially parallel to latitude circles and propagate southward at about 20 m s−1. Cellular features in the subsolar region undoubtedly imply convection there. The identificatiod of both bright- and dark-rimmed cells, with horizontal scales of about 200 and 500 km, respectively, implies a 15 km deep convective layer, based on an analogy with mesoscale convection in the terrestrial maritime atmosphere. The dark areas of the cells may be regions of downwelling. Variability in the location and intensity of the polar ring may be caused by a zonally propagating disturbance, perhaps related to the planetary wave producing the Y in lower latitudes. Circulation patterns and other atmospheric processes in the polar region may be rather different from elsewhere on the planet; only in the polar region are UV markings also visible in the orange.
Abstract
We provide morphological and kinematic desc6ptions of the UV markings seen in the Mariner 10 imagery of Venus: the dark horizontal Y, bow-like waves, circumequatorial belts, subsolar disturbance, spiral streaks and bands, polar ring and polar region. The dark horizontal Y is interpreted as a westward-propagating planetary wave with zonal wavenumber 1 and period ∼4.2 days; it may he the superposition of a Rossby-Haurwitz wave dominant at mid-latitudes and a Kelvin wave dominant in equatorial regions. Bow-like waves may be true bow waves formed by the interaction of the rapid zonal flow with internal gravity waves of lower horizontal phase speeds generated by the subsolar disturbance. Circumequatorial belts are interpreted as internal gravity waves with horizontal wavelength ∼500 km and zonal extent ∼5000 km. They are essentially parallel to latitude circles and propagate southward at about 20 m s−1. Cellular features in the subsolar region undoubtedly imply convection there. The identificatiod of both bright- and dark-rimmed cells, with horizontal scales of about 200 and 500 km, respectively, implies a 15 km deep convective layer, based on an analogy with mesoscale convection in the terrestrial maritime atmosphere. The dark areas of the cells may be regions of downwelling. Variability in the location and intensity of the polar ring may be caused by a zonally propagating disturbance, perhaps related to the planetary wave producing the Y in lower latitudes. Circulation patterns and other atmospheric processes in the polar region may be rather different from elsewhere on the planet; only in the polar region are UV markings also visible in the orange.
Abstract
Empirical studies of total outgoing infrared radiation IR and surface temperature T have shown them to be well correlated for large time and space scales. An analysis of one year of Nimbus-6 data shows that the simple form IR = A + BT (with A = 204 W m−2, B = 1.93 W m−2K−1) explains 90% of the area-weighted variance in the annual mean and annual cycle of the zonally averaged IR field. The geographical distribution of the annual cycle in IR shows a large amplitude over the continental interiors, as is found in the observed temperature field, and the ratio of the large amplitudes (Blocal ) is approximately 2 W m−2K−1. This helps to explain our recent success in modeling the geographical distribution of the annual cycle in T with a two-dimensional, time-dependent energy balance climate model (EBCM) which makes use of the A + BT rule. The parameterization works well in regions where the thermal inertia is small and the annual cycles of T and IR are large and in phase. Those regions where Blocal differs markedly from 2 W m−2K−1 are where the IR is strongly affected by the cloudiness of seasonal precipitation regimes. This effect is especially evident over the tropical oceans where the parameterization fails; but that is where the thermal inertia is large, the seasonal cycle in T is small, and even large errors in the radiative cooling approximation will have little impact on seasonal cycle simulations by simple climate models.
Abstract
Empirical studies of total outgoing infrared radiation IR and surface temperature T have shown them to be well correlated for large time and space scales. An analysis of one year of Nimbus-6 data shows that the simple form IR = A + BT (with A = 204 W m−2, B = 1.93 W m−2K−1) explains 90% of the area-weighted variance in the annual mean and annual cycle of the zonally averaged IR field. The geographical distribution of the annual cycle in IR shows a large amplitude over the continental interiors, as is found in the observed temperature field, and the ratio of the large amplitudes (Blocal ) is approximately 2 W m−2K−1. This helps to explain our recent success in modeling the geographical distribution of the annual cycle in T with a two-dimensional, time-dependent energy balance climate model (EBCM) which makes use of the A + BT rule. The parameterization works well in regions where the thermal inertia is small and the annual cycles of T and IR are large and in phase. Those regions where Blocal differs markedly from 2 W m−2K−1 are where the IR is strongly affected by the cloudiness of seasonal precipitation regimes. This effect is especially evident over the tropical oceans where the parameterization fails; but that is where the thermal inertia is large, the seasonal cycle in T is small, and even large errors in the radiative cooling approximation will have little impact on seasonal cycle simulations by simple climate models.
Abstract
Specially prepared sections of pictures taken with the Mariner 10 television cameras are composited to show the time development of UV markings at various locations on Venus. A second series of composite pictures shows the development of selected UV markings in a frame of reference which follows the apparent zonal motion. BY comparing these composites with individual TV pictures, we show that large-scale markings (∼1000 km) between ±45° latitude have lifetimes exceeding 4 days and move en masse with the apparent angular motion at the equator. Smaller scale markings (100−500 km) are found to have lifetimes in excess of 1.5 days but less than 4 days. The polar ring, bow-like waves, circumequatorial belts and cellular features all show rapid growth, modulation or propagation characteristics in the pictures. The long lifetime of large-scale markings permits us to interpret the time development pictures as spatial maps of the entire face of Venus at the time of Mariner 10 encounter. A single, dark, horizontal Y is found to encircle the planet. At high southerly latitudes (>40°) the large-scale pattern of markings is found to he decoupled from the mean flow as defined by small-scale markings. This is also the case for the polar ring which also shows noticeable diurnal changes. These observations suggest that the Y and the polar ring are both visible manifestations of propagating waves.
Abstract
Specially prepared sections of pictures taken with the Mariner 10 television cameras are composited to show the time development of UV markings at various locations on Venus. A second series of composite pictures shows the development of selected UV markings in a frame of reference which follows the apparent zonal motion. BY comparing these composites with individual TV pictures, we show that large-scale markings (∼1000 km) between ±45° latitude have lifetimes exceeding 4 days and move en masse with the apparent angular motion at the equator. Smaller scale markings (100−500 km) are found to have lifetimes in excess of 1.5 days but less than 4 days. The polar ring, bow-like waves, circumequatorial belts and cellular features all show rapid growth, modulation or propagation characteristics in the pictures. The long lifetime of large-scale markings permits us to interpret the time development pictures as spatial maps of the entire face of Venus at the time of Mariner 10 encounter. A single, dark, horizontal Y is found to encircle the planet. At high southerly latitudes (>40°) the large-scale pattern of markings is found to he decoupled from the mean flow as defined by small-scale markings. This is also the case for the polar ring which also shows noticeable diurnal changes. These observations suggest that the Y and the polar ring are both visible manifestations of propagating waves.
The Atmospheric Science Education Program (ASEP) established in 1986 at Purdue University had two components: (1) To conduct a summer program for teachers on topics in atmospheric science; and (2) To develop educational materials for teaching atmospheric science to grades five through nine.
The ASEP Summer Program for Teachers was conducted at Purdue University in July 1987 for selected Indiana teachers. Its purpose was to help teachers that teach science in grades five through nine to incorporate atmospheric science topics into their school curricula. The teachers participated in a four-week program that included lectures, laboratory sessions, educational applications seminars, field trips, and guest speakers.
The ASEP staff also developed a series of videotapes and an accompanying set of instructional booklets for students and teachers. These materials were designed to reach a nationwide audience of students and teachers of science so they could incorporate atmospheric-related activities into the general science classroom. The participating teachers in the summer program provided input on the suitability (for the targeted school grades) of these materials, which will become available in late 1988.
Follow-up visitations were made by ASEP staff to the schools of the summer participants to determine the impact of the summer program and to assist the teachers with implementation of atmospheric science into their science classrooms. These visitations and other correspondence with the participating teachers have revealed that the teachers are actively adapting the educational materials and components of the summer program instruction into their science curricula, as well as conducting in-service training for other teachers in their own school districts and at state science-teachers' meetings.
The Atmospheric Science Education Program (ASEP) established in 1986 at Purdue University had two components: (1) To conduct a summer program for teachers on topics in atmospheric science; and (2) To develop educational materials for teaching atmospheric science to grades five through nine.
The ASEP Summer Program for Teachers was conducted at Purdue University in July 1987 for selected Indiana teachers. Its purpose was to help teachers that teach science in grades five through nine to incorporate atmospheric science topics into their school curricula. The teachers participated in a four-week program that included lectures, laboratory sessions, educational applications seminars, field trips, and guest speakers.
The ASEP staff also developed a series of videotapes and an accompanying set of instructional booklets for students and teachers. These materials were designed to reach a nationwide audience of students and teachers of science so they could incorporate atmospheric-related activities into the general science classroom. The participating teachers in the summer program provided input on the suitability (for the targeted school grades) of these materials, which will become available in late 1988.
Follow-up visitations were made by ASEP staff to the schools of the summer participants to determine the impact of the summer program and to assist the teachers with implementation of atmospheric science into their science classrooms. These visitations and other correspondence with the participating teachers have revealed that the teachers are actively adapting the educational materials and components of the summer program instruction into their science curricula, as well as conducting in-service training for other teachers in their own school districts and at state science-teachers' meetings.
