Equations of motion

The fundamental equation governing the motion of air in a planetary atmosphere is the Navier-Stokes equation. Consider a parcel of air of volume SV Sx Sy Sz and density p. From Newton's Second Law, F ma and thus where V is the velocity vector. There are three main forces that may act on air parcels in a non-rotating planetary atmosphere gravity, the pressure gradient force, and friction. Incorporating these forces leads to the Navier-Stokes equation in an inertial frame where 7 is the viscosity...

Exact leastsquares and Backus Gilbert solutions

Suppose that we represent a set of measurements (channel radiances, or a whole spectrum measured at a set of discrete wavelengths) by the vector ym of m elements, known as the measurement vector. We may also represent atmospheric conditions with the state vector xn of n elements, which may contain the temperature, composition, cloud abundances, at appropriate levels in the atmosphere, etc. We may represent the radiative transfer model by a forward model F(xn), from which we may calculate the...

Diatomic homonuclear molecules

Diatomic homonuclear molecules do not interact with electromagnetic radiation via electric dipole transitions at all since no vibrational or rotational change of state may induce an electric dipole in the molecule. Although such molecules may interact weakly with electromagnetic radiation in other ways, they are usually effectively considered to be radiatively inactive in terrestrial atmospheres since their weak absorptions are totally dominated by the electric dipole transitions of other...

Illustrations

1.1 The giant planets as observed by the Voyager spacecraft together with the Earth for 1.2 Total thermal infrared radiation flux emitted by the giant planets as a function of 1.3 Jupiter as observed by Cassini in December 1.4 Jovian zonal 1.5 Saturn as observed by the Hubble Space Telescope in December, 1994 color 1.6 Saturn's rings behind 1.7 Saturn's night side as seen by Cassini ISS, with the Sun directly behind Saturn's 1.8 False-color image of Saturn and its 1.9 Uranus observed by Voyager...

Meteorology Of Neptune General circulation and zonal structure

The atmosphere of Neptune is powered by extremely low energy fluxes. Internal heat energy flux is estimated to be 0.45 Wm-2 (Table 3.2) while the absorbed solar flux is estimated to be 0.27Wm-2, compared with values of 0Wm-2 and 205.5Wm-2, respectively, for the Earth. However, the cloud top zonal winds on Neptune are found to be very high with an extremely fast westward retrograde equatorial jet reaching speeds of 400 ms-1, gradually decreasing in the poleward direction and becoming eastward...

Meteorology Of Saturn General circulation and zonal structure

Saturn emits 1.78 x more energy than it receives from Sun, but compared with Jupiter the overall energy emission is much less (only 1 3 that of Jupiter). Hence, it might be expected that Saturn should have a commensurately less vigorously overturning atmosphere. However, the atmosphere appears just as energetic as Jupiter's with strong zonal winds that reach speeds of 400 m s-1 in the eastward-flowing equatorial jet. Although the atmosphere is very dynamic, the appearance of Saturn is generally...

Neptune Radio Emissions Ground Based

Overlap spectral regions between thermal emission (solid) and reflected sunlight (dotted) for the giant planets. Calculated reflection is from a Lambertian layer with albedo 0.1 placed at 1 bar for Jupiter and Saturn, and 3 bar for Uranus and Neptune. Radiance units are again Wcm-2 sr-1 (cm-1)-1. The thermal emission spectrum of Saturn is in many respects rather similar to that of Jupiter, but of significantly lower overall brightness. Spectral features are formed from similar gas...

Tropospheric circulation and jets

Rotating Tank Spin Down And Spin

We have seen that the zonal wind circulation of the giant planets is very vigorous. What is not so clear, however, is how these jets are initiated, maintained, and how deep into the interior these zonal winds extend. In this section we will review some the modeling work that has been done to understand the mean circulation of the giant planet atmospheres. The Rhines length Lp was introduced in Section 5.3.1, in the context that vortices in a two-dimensional turbulent flow will grow via the...

Storms and vortices

The cloud features that are visible on Saturn appear to be the tops of active convection systems that push their way up into the overlying semitransparent region. While generally less active than Jupiter's atmosphere, a number of spots have been observed in Saturn's atmosphere from ground-based observations over many years (Sanchez-Lavega, 1982). Like Jupiter, cloud tracking of the motion of eddies in Saturn's atmosphere suggests that it is the small eddies that drive the zonal jets and not...

Meteorology Of Jupiter General circulation and zonal structure

Jupiter emits 1.67 x more radiation than it receives from the Sun indicating a substantial internal heat source and hence, presumably, vigorous convection. The zonal structure of Jupiter appears to be neutrally stable with well-defined belts and zones (summarized in Figure 1.4 and reviewed in great detail by Rogers, 1995). In fact, this canonical stable belt zone structure is a little misleading since the dark belts occasionally brighten and the bright zones occasionally darken with typical...

Uranus Composition profiles

In Chapter 2 we saw that the observable atmosphere of Uranus (Figure 4.19, see color section) has much higher levels of methane than Jupiter and Saturn, and a much greater D H ratio. The methane v.m.r. was estimated to be 2.3 from Voyager 2 radio occultation measurements (Lindal et al., 1987). Later ground-based visible hydrogen quadrupole measurements suggested a figure closer to 1.6 (Baines et al., 1995b), and more recent estimates from ground-based near-IR observations put the abundance as...

Photopolarimeter Isophot

The ISO imaging photo-polarimeter, ISOPHOT, was composed of three subsystems optimized for specific photometric modes. These were 1 PHT-P, a multi-band, multi-aperture photometer with three single detectors covering the wavelength range 3 m to 120 m from the near-infrared to the far-infrared 2 PHT-C, two photometric far-IR cameras for the wavelength range 50 m to 240 m and 3 PHT-S, two grating spectrophotometers, operated simultaneously, for the wavelength ranges of about 2.5 m to 5 m and 6 m...

Observed Atmospheres Of The Giant Planets

The observable atmospheres of the giant planets are dominated by molecular hydrogen and helium, in proportions roughly similar to that found in the Sun. The abundance of heavy elements which in this context refers to elements heavier than helium is found, or estimated, to be approximately 3-5 times the solar value for Jupiter, 10 times the solar value for Saturn, increasing to 30-50 times the solar value Figure 1.2. Total thermal-infrared radiation flux Wm 2 emitted by the giant planets as a...

Overtones and hot bands

The vibrational selection rule Av 1 for electric dipole transitions is only absolute for a pure simple harmonic oscillator. The binding force between real molecules, while proportional to displacement for small oscillations, has non-negligible higher orders, or anharmonic elements for larger oscillations. These anharmonic elements relax the selection rules to Av 1, 2, 3, giving rise to overtone bands, for V symmetric stretch V' bend A v bend B v.i asymmetric stretch which gt 1. Overtone bands...

Constraints on formation DH ratio

As the presolar cloud collapsed into a circumstellar disk incoming material arriving from the presolar cloud would have been subjected to appreciable reprocessing both through the collapse process itself, and also through shocking as the material entered the dense nebula. Both these effects are likely to have been more substantial near the Sun and less important at greater distances. Some models suggest that the water molecules in the ices were completely dissociated by this process and then...

Imaging Photopolarimeter

To run out of power, and thus lose contact with the Earth, sometime in the next 20 years. Pioneer 11 was identical to Pioneer 10 except that a flux-gate magnetometer was also added. The spacecraft was launched on April 5, 1973 and flew past Jupiter on December 2, 1974 at an even lower altitude of 0.6 Rj 43,000 km . Pioneer 11 arrived from south of Jupiter's equator and left from above allowing imaging of Jupiter's North Polar region. Its trajectory then took it across the solar system to fly...

Very Large Baseline Array VLBA

The VLBA is a series of ten 25 m diameter radio antennas located at sites across the continental United States, and on Mauna Kea, Hawaii, and St. Croix in the U.S. Virgin Islands. Work on its construction began in 1985 and the last VLBA station on Mauna Kea, Hawaii, was completed in 1993. Because of its extremely long baseline and large collecting area, the VLBA has a maximum angular resolution of less than one-thousandth of an arcsecond at A 7 mm , and covers a wavelength range of 3 mm to 90...

Effective radiating temperature of planets

The Sun radiates essentially as a black body, with an effective surface temperature Ts 5,750 K and radius Rs 700,000 km. Applying Stefan-Boltzmann's law we find that the total power radiated by the Sun in all directions is Es a 4-RS TS 3.8 x 1026 W. 3.28 where a is the Stefan-Boltzmann constant. The flux of sunlight W m 2 arriving at a planet at distance D from the Sun is simply this power divided by the surface area of a sphere of radius equal to the distance to the Sun that is, At the Earth's...