Statistical cloud schemes with prognostic probability distribution functions have become more important in atmospheric modeling, especially since they are in principle scale adaptive and capture cloud physics in more detail. While in theory the schemes have a great potential, their accuracy is still questionable. High-resolution three-dimensional observational data of water vapor and cloud water, which could be used for testing them, are missing. We explore the potential of ground-based remote sensing such as lidar, microwave, and radar to evaluate prognostic distribution moments using the “perfect model approach.” This means that we employ a high-resolution weather model as virtual reality and retrieve full three-dimensional atmospheric quantities and virtual ground-based observations. We then use statistics from the virtual observation to validate the modeled 3-D statistics. Since the data are entirely consistent, any discrepancy occurring is due to the method. Focusing on total water mixing ratio, we find that the mean ratio can be evaluated decently but that it strongly depends on the meteorological conditions as to whether the variance and skewness are reliable. Using some simple schematic description of different synoptic conditions, we show how statistics obtained from point or line measurements can be poor at representing the full three-dimensional distribution of water in the atmosphere. We argue that a careful analysis of measurement data and detailed knowledge of the meteorological situation is necessary to judge whether we can use the data for an evaluation of higher moments of the humidity distribution used by a statistical cloud scheme.

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Researchers analyzing the upper clouds of Jupiter and Saturn are unable to theoretically reproduce the data returned by Pioneers 10 and 11 and Voyagers 1 and 2 with an approach based on Mie theory. Ammonia crystals are believed to be an important constituent of Jupiter's upper clouds, but both their shape and scattering properties were unknown at the start of this work. Ammonia crystals and water crystals were grown in a cold chamber at temperatures 20°C below their freezing points (0°C and -77.7°C, respectively). The H₂O crystals formed had shapes in agreement with published growth habit diagrams. The NH₃ crystals formed were usually irregular in shape, but regular four-sided pyramids were commonly observed. This four-sided pyramidal shape is in agreement with ammonia's primitive cubic crystal structure. Ammonia crystals could not be formed at temperatures above -95°C due to nucleation problems. A scattering measuring instrument was constructed with fifteen separate lens-detector combinations aimed at a common point in the center of the cold chamber. A laser beam (6328Å wavelength) traversed the chamber center, illuminating any crystal aerosal clouds present. A computer was used to rapidly sample the outputs of the fifteen detectors and to drive a photoelectric modulator to change the slow speed polarization properties of the laser beam. The measurements resulted in a determination of the single scattering phase function and degree of linear polarization for the crystal species present. Water crystals were found to have scattering properties similar to that reported by previous researchers. The H₂O crystal scattering possesses a smaller backscatter peak and smaller polarization features than is common for water spheres of similar size. A negative polarization of 5% occurred in the forward scattering hemisphere and a positive polarization of 10% in the rear. Ammonia particles were observed to have a backscattering peak four times higher than for water crystals. The NH₃ particle light scattering produced very little polarization of the scattered light. A small (∼ 4%) negative polarization occurred in the forward scattering hemisphere. Work is continuing here to make scattering measurements using blue light illumination nearly simultaneous with the red HeNe laser wavelength illumination.

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I studied the atmospheric jet streams of Jupiter and Saturn through numerical simulations. Jupiter and Saturn have approximately 30 and 15 jet streams, respectively, alternatively blowing eastward and westward at the cloud level. My studies are motivated by recent space probe observations of the giant planets, which are revealing vertical structures and time dependent behaviors of the atmospheric jets. Such new findings are important keys to understanding how the jets are driven and maintained. My first project tested the hypothesis that a large convective storm on Saturn observed in 1990 decelerated the equatorial jet. The equatorial jet's speed is reported to be ∼275 ms⁻¹ today, half of the speed measured by the Voyagers in 1980-81. It has been hypothesized that the large storm is responsible for causing the observed slowdown. Our result shows that the storm's effect is insufficient to cause a slowdown of the observed magnitude. The second project investigated the formation of Jovian jet streams, namely, whether Jupiter-like atmospheric jets emerge from self-organization of small initial vortices. Thunderstorms are observed on Jupiter and have been proposed to be the sources of small-scale vorticity. Our result shows that self-organization of initial small vortices leads to east-west jets under various Jupiter-like conditions. Third, I tested the stability of shallow atmospheric jets under Jovian conditions. Deep atmospheric jets have been shown to be stable on Jupiter; however, the possibility that those jets are shallow, with the point of zero-motion at perhaps ∼100-bar level, is not well explored and deserves a thorough examination.

The Phoenix mission investigated patterned ground and climate in the northern arctic region of Mars for 5 months starting May 25, 2008. A shallow ice table was uncovered by the robotic arm in a nearby polygon's edge and center at depths of 5-15 cm. In late summer snowfall and frost blanket the surface at night; water ice and vapor constantly interact with the soil. Analysis reveals an alkaline Ph with CaCO3, aqueous minerals, and salts making up several wt% of the soil; liquid water is implicated as having been important in creating these components. In combination with the oxidant perchlorate (~1 wt%), an energy source for terrestrial microbes, and a prior epoch of higher temperatures and humidity, this region may have been a habitable zone.

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The theme of social-psichological atmosphere at a hostel of a vosational school was not discussed much and no doubt is very important.

In this report a radar model is modeled and implemented in a simulation framework called Flames. The focus is to investigate how and if electromagnetic waves emitted from the radar antenna can be simulated by different methods and how these methods can be implemented to work in real-time simulations. The radar model developed in this report is based on ray tracing and ray propagation techniques developed by the author. The model considers varying refractive indices that describes both standard atmospheres and atmospheres where ducting occur. Preparatory studies are also made to model ground reflection by ray tracing techniques. Other simulation techniques, such as the Finite-Difference Time-Domain method and the Split-Step Parabolic Equation method, are furthermore considered for radar simulation applications. The results show that ray tracing in conjunction with geometrical optics is a valid method for simulating electromagnetic waves in simple atmosphere models.