Abstract. Thermal structure of the atmosphere of Jupiter was measured from 1029 km above to 133 km below the 1-bar level during entry and descent of the Galileo probe. The data confirm the hot exosphere observed by Voyager (---900 K at 1 nanobar). The deep atmosphere, which reached 429 K at 22 bars, was close to dry adiabatic from 6 to 16 bars within an uncertainty ---0.1 K/km. The upper atmosphere was dominated by gravity waves from the tropopause to the exosphere. Shorter waves were fully absorbed below 300 km, while longer wave amplitudes first grew, then were damped at the higher altitudes. A remarkably deep isothermal layer was found in the stratosphere from 90 to 290 km with T ---160 K. Just above the tropopause at 260 mbar, there was a second isothermal region ---25 km deep with T ---112 K. Between 10 and 1000 mbar, the data substantially agree with Voyager radio occultations. The Voyager 1 equatorial occultation was similar in detail to the present sounding through the tropopause region. The Voyager IRIS average thermal structure in the north equatorial belt (NEB) approximates a smoothed fit to the present data between 0.03 and 400 mbar. Differences are partly a result of large differences in vertical resolution but may also reflect differences between a hot spot and the average NEB. At 15 < p < 22 bars, where it was necessary to extrapolate the pressure calibration to sensor temperatures up to 118øC, the data indicate a stable layer in which stability increases with depth. Consistent with the indication of stability, regular fluctuations in probe vertical velocity imply gravity waves in this layer. At p > 4 bars, probe descent velocities derived from the data are consistently unsteady, suggesting the presence of large-scale turbulence or gravity waves. However, there was no evidence of turbulent temperature fluctuations >0.12 K. A conspicuous pause in the rate of decrease of descent velocity between 1.1 and 1.35 bars, where a disturbance was also detected by the two radio Doppler experiments, implies strong vertical flow in the cloud seen by the probe nephelometer. At p < 0.6 bar, measured temperatures were ---3 K warmer than the dry adiabat, possible evidence of radiative warming. This could be associated with a tenuous cloud detected by the probe nephelometer above the 0.51 bar level. For an ammonia cloud to form at this level, the required abundance is ---0.20 x solar. IntroductionThis paper reports principal results of the Galileo probe atmosphere structure experiment. The primary goal of the experiment was to define the thermal structure of Jupiter's atmosphere below the clouds, a region inaccessible to remote sensing, by direct sensing of atmospheric temperature and , 1996]. It was our intent to obtain measurements through and well below the clouds, to improve accuracy and resolution, and so to define the atmospheric stability against overturning, observe thermal effects of clouds, detect and quantify turbulence, and make other dynamical observations.Densities at a few levels in the upper atmosp...

The Mars Global Surveyor (MGS) z -axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have been detected on opposite sides of the planet near 90°E and 90°W, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere.

Thermal structure of the atmosphere of Venus, and differences in structure with latitude (up to 60°) and clock hour (from midnight to 8 A.M.) have been measured in situ from an altitude of 126 km to the surface by instruments on the four Pioneer Venus entry probes. Several indications from the preliminary analyses are confirmed by the current analysis: Thermal contrasts below 45 km are a few K, with the mid‐latitudes warmer than both equatorial and the high latitudes. Sizeable temperature and pressure differences with latitude develop in the clouds (25 K and 20 mbar at the 200 mbar level). At 30° latitude, diurnal differences were small throughout the lower atmosphere from midnight to 7 A.M. A major stable layer 25 km deep exists just below the clouds. Waves of global extent were observed within this layer. A locally stable layer is indicated in the deep atmosphere, between 10 and 20 km, at latitudes up to 30°. In the middle cloud and immediately below the deep stable layer, the atmosphere is approximately neutrally stable, and there is evidence for convective overturning below the stable layer. Just above the clouds, the lapse rate becomes stable, and a ‘stratosphere’ begins which extends upwards to 110 km, becoming isothermal above 85 km. The stratospheric temperature profiles were essentially the same in three widely separated soundings. Upward of 110 km, there is evidence of large amplitude temperature oscillations with altitude, believed to signify the presence of large amplitude waves, perhaps thermal tides. By comparing data of several experiments, it is found that the large diurnal variations in the upper atmosphere begin at an altitude ∼115 km. Agreement of structure data from other Pioneer Venus experiments with the present results is generally excellent. Our measurements of the winds derived from Doppler data agree well with DLBI results and indicate a retrograde zonal velocity of 113 m/s at 63 km altitude and 30° latitude. The zonal winds predicted at cloud levels from pressure differences between 60° latitude and the mid‐latitude probes by assumption of cyclostrophic balance are in first order agreement with the observed winds. At latitudes below ∼30°, however, cyclostrophic balance of the zonal winds is not the dominant process. At altitudes from 60 to 105 km, the measured pressure differences and the assumption of cyclostrophic balance indicate zonal wind velocities peaking at 155 m/s at 68 km, remaining above 120 m/s up to 95 km, then decreasing rapidly.

Temperatures in Jupiter's atmosphere derived from Galileo Probe deceleration data increase from 109 kelvin at the 175-millibar level to 900 ± 40 kelvin at 1 nanobar, consistent with Voyager remote sensing data. Wavelike oscillations are present at all levels. Vertical wavelengths are 10 to 25 kilometers in the deep isothermal layer, which extends from 12 to 0.003 millibars. Above the 0.003-millibar level, only 90- to 270- kilometer vertical wavelengths survive, suggesting dissipation of wave energy as the probable source of upper atmosphere heating.

The primary objective of the Mars Path nder mission was to demonstrate an innovative, low-cost, reliable method for placing a science payload on the surface of Mars. The spacecraft performance during entry, descent, and landing is assessed. Analysis of the accelerometer and altimeter ight data obtainedby the Path nder spacecraft during atmospheric ight is provided. Results of an effort to reconstruct the spacecraft trajectory and attitude history are presented. An estimate of the Mars atmosphere pro le encountered during atmospheric ight is given. ½ = atmospheric density, kg/m 3 ! obs = observed vehicle roll rate, rad/s ! z = roll rate about the vehicle Z axis, rad/s

Temperatures and pressures measured by the Galileo probe during parachute descent into Jupiter's atmosphere essentially followed the dry adiabat between 0.41 and 24 bars, consistent with the absence of a deep water cloud and with the low water content found by the mass spectrometer. From 5 to 15 bars, lapse rates were slightly stable relative to the adiabat calculated for the observed H2/He ratio, which suggests that upward heat transport in that range is not attributable to simple radial convection. In the upper atmosphere, temperatures of >1000 kelvin at the 0.01-microbar level confirmed the hot exosphere that had been inferred from Voyager occultations. The thermal gradient increased sharply to 5 kelvin per kilometer at a reconstructed altitude of 350 kilometers, as was recently predicted. Densities at 1000 kilometers were 100 times those in the pre-encounter engineering model.

Calculations on time dependence of the inner Van Allen belt proton population show that large changes of the population up to a factor of 50 will take place during the solar cycle. The effect is most pronounced for the region of B‐L space corresponding to minimum altitudes of 300–700 km. Because protons of different energies respond to the changing solar cycle at different rates, the proton energy spectrums will change with time also.

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