Solar variability effects studied by tree-ring data wavelet analysis

The global change approach to study the Sun-Earth system gives a growing amount of evidences that climate dynamics is affected by a large number of factors. The solar variability is very likely to be among them. Natural records, such as tree ring data, can be investigated to study the past global and regional climate, which was influenced by the solar radiative output variations, associated to solar activity. Wavelet transform analysis was applied to sunspot number and tree ring width time series from 1837 to 1996 at Concórdia, Brazil. The amplitude and cross-amplitude spectral representation in the time-frequency domain allowed us to detect the occurrence of predominant periodicities and the relationship between the sunspot number and the tree ring time series. The Morlet complex wavelet analysis was used to study the most important variability factors on time scales ranging from from 2 to 100 years, and their stability in time, which is shown in both time series studied. We also applied the cross-wavelet spectral analysis to evaluate time delay among different tree ring time series, and between tree ring and sunspot number time series.     

Arthropod model systems for studying complex biological processes in the space environment.

Three arthropod systems are discussed in relation to their complementary and potential use in Space Biology. In a next biosatellite flight, Drosophila melanogaster pre-adapted during several months to different g levels will be flown in an automatic device that separates parental from first and second generations. In the same flight, flies will be exposed to microgravity conditions in an automatic unit in which fly motility can be recorded. In the International Microgravity Laboratory-2, several groups of Drosophila embryos will be grown in Space and the motility of a male fly population will be video-recorded. In the Biopan, an ESA exobiology facility that can be flown attached to the exterior of a Russian biosatellite, Artemia dormant gastrulae will be exposed to the space environment in the exterior of the satellite under a normal atmosphere or in the void. Gastrulae will be separated in hit and non-hit populations. The developmental and aging response of these animals will be studied upon recovery. With these experiments we will be able to establish whether exposure to the space environment influences arthropod development and aging, and elaborate on some of the cellular mechanisms involved which should be tested in future experiments.     

Phase modulated DGPS transmitter implemented with a clamped-mode resonant converter

A clamped-mode resonant converter (CMRC) is proposed to be used as a transmitter which broadcasts correction signals in a differential Global Positioning System (DGPS). The digital information of the DGPS modulates the carrier with different modulation methods minimum shift keying (MSK) (recommended for the marine radiobeacon band), stepped binary phase shift keying (S-BPSK) and BPSK. The first two methods allow keeping the converter's operation in soft switching mode. Extensive trials under impedance mismatch and modulation conditions confirm that the soft switching mode is preserved.     

Remote sounding of atmospheric gravity waves with satellite limb and nadir techniques

Recent advances in satellite techniques hold great potential for mapping global gravity wave (GW) processes at various altitudes. Poor understanding of small-scale GWs has been a major limitation to numerical climate and weather models for making reliable forecasts. Observations of short-scale features have important implication for validating and improving future high-resolution numerical models. This paper summarizes recent GW observations and sensitivities from several satellite instruments, including MLS, AMSU-A, AIRS, GPS, and CLAES. It is shown in an example that mountain waves with horizontal wavelengths as short as 30 km now can be observed by AIRS, reflecting the superior horizontal resolution in these modern satellite instruments. Our studies show that MLS, AMSU-A and AIRS observations reveal similar GW characteristics, with the observed variances correlated well with background winds. As a complementary technique, limb sounding instruments like CRISTA, CLAES, and GPS can detect GWs with better vertical but poorer horizontal resolutions. To resolve different parts of the broad GW spectrum, both satellite limb and nadir observing techniques are needed, and a better understanding of GW complexities requires joint analyses of these data and dedicated high-resolution model simulations.     

A Modification of the Method of Transporting Trajectory

Further development of an approximate method for optimizing a flight with an ideally controlled small thrust is proposed. The method is based on the employment of the transporting trajectory and considered in [1–3]. A detailed analysis of the means of improving the accuracy of this method suggested in [2, 3] is carried out, and the solution is presented in finite form. The proposed approach is applied to the flights making flybys of many celestial bodies. In the case of small bodies the solution is also obtained in finite form. A numerical example is considered confirming the high efficiency of this method.     

Satellite altimetry determination of differences between mean sea-level heights and testing geopotential models

The Satellite Altimeter Data has been used for a) Determination of differences between mean ocean levels; b) Testing the accuracy of different geopotential models as regards their internal structure over the oceans.     

A review of geostationary satellite alternatives for retrieving data from long duration balloon flights

Low speed data from high altitude scientific balloon flights can be retrieved by geostationary satellites through existing data collection platform systems. Higher speed data of the order of 1 kbit/s create a more difficult problem, particularly if a response is to be made to the balloon payload in near real time. Different geostationary satellite methods to achieve these more demanding requirements are reviewed, and the more interesting cases identified for possible future experiments.     

Synchrotron radiation as a probe of the inner magnetosphere of Jupiter

A short review is given on the characteristics of Jupiter's inner magnetosphere derived from radio observations in the decimetric wavelength range. A comparison of the data with sophisticated model calculations yields information on the magnetic field configuration and the electron distribution, its density, energy spectrum, and pitch angle dependence as a function of spatial coordinates. The latter information can be used to derive e.g. the radial diffusion parameters plus the effects of the satellites, Jupiter's ring, and wave-particle interactions upon the electron distribution.     

Solar maximum mission experiment: Early results of the hard X-ray imaging experiment

We have selected four widely different flares from the early period of operations of the Hard X-Ray Imaging Spectrometer (HXIS) on SMM to illustrate the characteristic imaging properties of this experiment. For the small flare of April 4, 1980, we demonstrate the instrument's capability for locating a compact source. In the weak, but extensive, flare of April 6 we show how well the instrument can display spatial structure, and also the low level of the instrument background. In the 1B flare of April 7 we are able to locate positions of the X-ray emission in the soft and hard channels, and estimate the positional variations of the emission patches. Finally, in the IN flare of April 10, which produced the strongest hard X-ray burst we have seen so far, we repeat some of the studies made for the April 7 event, and also demonstrate the capability of the HXIS instrument to study the development, with high time resolution, of individual 8″ × 8″ elements of the flare.