George Y. Jumper

Effect of Compressible Flow on Perceived Temperature Fluctuations Measured by Moving Sensor

Equations are developed for the effect of velocity fluctuations on the perceived temperature fluctuations detected by a moving temperature sensor. The impact of these fluctuations on perceived fluctuations of index of refraction are computed. The magnitude of this effect is estimated using known ranges of atmospheric fluctuations in temperature and velocity. Using a method to estimate velocity fluctuations from temperature fluctuations and concurrently measured atmospheric data, balloon derived fluctuation data is used to estimate what would be perceived by a faster moving sensor. We conclude that normally observed fluctuations can have a significant impact on the perceived optical properties. NOMENCLATURE a = Constant b = Constant Br(x) = Spatial Covariance (units of r squared) Cx2 = Structure constant of the quantity x (units are the units of x^m273) CP = Specific heat at constant pressure (J/kg/K) Dx(r) = Structure function of quantity x (units are the units of x squared) d = Distance (m)

In Situ Measurement of Waves and Turbulence in the T-REX Campaign

The Air Force Research Laboratory participated in the NSF Terrain Rotor Experiment (TREX) from 20 March through 6 April 2006, which included 3 intensive observation periods (IOPs) of the 15 IOPs of the two month T-REX campaign. AFRL focused on the higher altitude turbulence associated with mountain waves. The AFRL flew thermosondes to measure optical turbulence up to 30km. They include a radiosonde to measure meteorological data. Standard radiosondes were also launched to sense atmospheric data including atmospheric wave signatures. These instruments were launched from the windward side of the Sierra Nevada Mountains in order to try to examine the atmosphere at high altitudes. Fifteen thermosondes launches and 10 radiosonde launches were successful. Many of the launches showed evidence of mountain waves, some accompanied by high levels of optical turbulence

Opening a new window on the southern stars for less money: PAIX the first Antarctica polar mission photometer

In this invited paper, we implement a new way to study the stellar oscillations, pulsations and their evolutionary properties with long uninterrupted and continuous precision observations over 150 days from the ground, and without the regular interruptions imposed by the earth rotation. PAIX–First Robotic Antarctica Polar Mission– gives a new insight to cope with unresolved stellar enigma and stellar oscillation challenges and offers a great opportunity to benefit from an access to the best astronomical site on Earth –DomeC–. The project is made of low cost commercial components, and achieves astrophysical measurement time-series of stellar physics fields, challenging photometry from space that shows large gaps in terms of flexibility during the observing runs, the choice of targets, the repair of failures and the inexorable high costs. PAIX has yet more advantages than space missions in observing in UBV RI bands and then collecting unprecedented simultaneous multicolor light curves of several targets. We give a brief history of the Astronomy in Antarctica and describe the first polar robotized mission PAIX and the outcome of stellar physics from the heart of Antarctica during several polar nights. We briefly discuss our first results and perspectives on the pulsating stars and its evolution from Antarctica, especially the connection between temporal hydrodynamic phenomena and cyclic modulations. Finally, we highlight the impact of PAIX on the stellar physics study and the remaining challenges to successfully accomplish the Universe explorations under extreme conditions.

Role of Grid Adaptation in Optical Turbulence Prediction

New grid adaptation approaches have been developed for the dynamic solution adaptation grid algorithm (DSAGA) to improve grid refinement for optical turbulence prediction. The grid adaptation algorithm and a four-equation hybrid LES/RANS turbulence model developed earlier have been incorporated into the numerical weather prediction code MM5 (adaptive version) to provide a new approach for the calculation of C 2 n, a quantitative measure of atmospheric optical turbulence. By comparing with observation, the numerical results suggest that combination of the new grid adaptation scheme and the turbulence model is capable of improving C 2 prediction with dynamic grid refinement in the stratosphere with little increase in computational eort.

Window to the universe for less money: 10 years of PAIX in Antarctica

Time has come to implement a new way to study the stellar physics from the ground with long-term uninterrupted time series, multi-color photometry, flexibility during observing runs and all for less money. PAIX, Photometer AntarctIca eXtinction, gives new insight to cope with unresolved stellar enigma and stellar oscillation challenges and bears witness, for the first time, to a new technology of the polar instrumental robotization under extreme human and weather conditions in the heart of Antarctica. In fact, the stellar pulsation plays a crucial role in understanding the Universe, however progress is limited by the data accuracy needed to detect numerous modes of oscillations with small amplitudes and by the discontinuous nature of typical ground-based data strings which often introduce ambiguities in the determination of oscillation frequencies. The recent space missions enable to overcome both difficulties, However, the outcome of the space missions shows large gaps in terms of flexibility during the observing runs, the choice of targets, the repair of failures and the inexorable high costs. We present here the new technology from Antarctica, in particular from South Polar Site Dome C that benefits from great image quality and 150 days high time coverage, where the seeing reaches a median value of 1 arcsec during the polar night. We briefly describe the instrumental performances of PAIX, its low-cost commercial components, robotic telescope, multi-band photometer and automatic control, working under harsh weather conditions, even when the temperature reach values as low as -80°C. The polar mission PAIX challenges the space missions and even has more advantages than CoRoT and KEPLER in observing in UBVRI bands and then collecting multicolor light curves simultaneously of several targets. We discuss here the first outcomes of stellar physics from the heart of Antarctica during 10 polar nights and PAIX new results and perspectives on the pulsating stars from Antarctica, especially the connection between the stellar pulsation enigma and the Universe mysteries. Finally, we highlight the impact of PAIX -the robotic Antarctica photometer- on the Astronomy development.

Improved Prediction of Optical Scale Turbulence- Progress and Future Directions

New grid adaptation approaches have been developed for the dynamic solution adaptation grid algorithm (DSAGA) to improve grid renement for optical turbulence prediction. The grid adaptation algorithm and a four-equation hybrid LES/RANS turbulence model developed earlier have been incorporated into the numerical weather prediction code MM5 (adaptive version) to provide a new approach for the calculation of C 2 n, a quantitative measure of atmospheric optical turbulence. By comparing with observation, the numerical results suggest that combination of the new grid adaptation scheme and the turbulence model is capable of improving C 2 prediction with dynamic grid renement in the stratosphere with little increase in computational eort.