Tidal associated temperature disturbances observed at the middle atmosphere (30–65 km) by a Rayleigh lidar at 23°S

A lidar has been operated in São José dos Campos, Brazil (23.2°S, 45.8°W) since 1972, mainly dedicated to the study of mesospheric sodium at the 589 nm resonant line. The molecular Rayleigh scattering can also be used provided we limit the height to ∼75 km where the sodium scattering begins. Nevertheless, the weak signal obtained only permits the determination of density and temperature profiles by accumulating a large number of shots giving only nocturnal average profiles. Temporal variations in density and temperature on the scale of hours can however, be obtained by performing a superposed epoch analysis for a given time interval and covering a period of several days. In this way we obtained hourly mean profiles grouped by months, seasons and overall, with data acquired from 1993 to 2004. The difference between the hourly temperatures and the nocturnal means shows for some months, with enough data coverage, downward propagating structures that apparently have tidal origin. The seasonal averages show a recurrent feature with high temperatures before and low temperatures after midnight above 50 km. Some similarity is found with the GSWM model, but the observed temperature amplitudes are twice of that for the model.     

Responses of ionospheric foF2 to geomagnetic activities in Hainan

Responses of low-latitude ionospheric critical frequency of F2 layer to geomagnetic activities in different seasons and under different levels of solar activity are investigated by analyzing the ionospheric foF2 data from DPS-4 Digisonde in Hainan Observatory during 2002–2005. The results are as follows: (1) the response of foF2 to geomagnetic activity in Hainan shows obvious diurnal variation except for the summer in low solar activity period. Generally, geomagnetic activity will cause foF2 to increase at daytime and decrease at nighttime. The intensity of response of foF2 is stronger at nighttime than that at daytime; (2) seasonal dependence of the response of foF2 to geomagnetic activity is very obvious. The negative ionospheric storm effect is the strongest in summer and the positive ionospheric storm effect is the strongest in winter; (3) the solar cycle has important effect on the response of foF2 to geomagnetic activity in Hainan. In high solar activity period, the diurnal variation of the response of foF2 is very pronounced in each season, and the strong ionospheric response can last several days. In low solar activity period, ionospheric response has very pronounced diurnal variation in winter only; (4) the local time of geomagnetic activities occurring also has important effect on the responses of foF2 in Hainan. Generally, geomagnetic activities occurred at nighttime can cause stronger and longer responses of foF2 in Hainan.     

Simulation experiments of the cosmic ray isotope telescope on ETS VI

A computer simulation was carried out to evaluate the basic characteristics of a Δ E×E cosmic ray telescope consisting of 23 solid state detectors including 3 position sensitive detectors with large effective area. Based on the simulation, the geometric factor of the telescope is deduced to be as large as 22.5 cm²sr, almost independent of charge and energy concerned. The energy ranges to be covered by the telescope are, for example, 18–98 MeV/n for Li and 56–339 MeV/n for Fe. By analyzing simulated data, the mass resolution for iron in the overall energy range covered by the telescope is estimated as about 0.22 amu in standard deviation. The expected counting rates and mass-histograms are simulated for Galactic cosmic rays and solar energetic particles.     

The Flight 2000 avionics suite: paving the way to free flight

The FAA's Flight 2000 project is an innovative initiative to implement and validate selected operational improvements leading to Free Flight. It integrates new avionics, new ground systems, new procedures, avionics certification, and operational approval. Approximately 2000 aircraft operating in Alaska, Hawaii, and Oceanic airspace will be equipped with new capabilities enabling benefits such as improved situational awareness, increased flexibility, and efficiency gains. By developing and fielding these operational improvements, the actual benefits of new procedures and capabilities will be validated and risks associated with national implementation will be reduced     

Long clinostation influence on the localization of free and weakly bound calcium in cell walls of Funaria hygrometrica moss protonema cells.

The pyroantimonate method was used to study the localization of free and weakly bound calcium in cells of moss protonema of Funaria hygrometrica Hedw. cultivated on a clinostat (2rev/min). Electroncytochemical study of control cells cultivated at 1 g revealed that granular precipitate marked chloroplasts, mitochondria, Golgi apparatus, lipid drops, nucleoplasma, nucleolus, nucleus membranes, cell walls and endoplasmic reticulum. In mitochondria the precipitate was revealed in stroma, in chloroplast it was found on thylakoids and envelope membranes. The cultivation of protonema on clinostat led to the intensification in cytochemical reaction product deposit. A considerable intensification of the reaction was noted in endomembranes, vacuoles, periplasmic space and cell walls. At the same time analysis of pectinase localization was made using the electroncytochemical method. A high reaction intensity in walls in comparison to that in control was found out to be a distinctive peculiarity of the cells cultivated on clinostat. It testifies to the fact that increasing of free calcium concentrations under conditions of clinostation is connected with pectinic substances hydrolysis and breaking of methoxy groups of pectins. Data obtained are discussed in relation to problems of possible mechanisms of disturbance in calcium balance of plant cells and the role of cell walls in gomeostasis of cell grown under conditions of simulated weightlessness.     

Interpretation of data on laser sensing of aerosol atmosphere from space

A single-frequency lidar, using aerosol scattering as an informative component, is the simplest and reliable facility for remote sensing of the atmosphere. The information on vertical distribution of atmospheric aerosol which can be obtained using such a lidar is necessary for investigating the physics of atmospheric processes and forecast of optical state of the atmosphere. At the same time, the interpretation of data on single-frequency sounding is associated with some difficulties of fundamental character, mainly due to insufficient software of the experiment. Under such conditions the problems of optimal processing of lidar returns aiming at extracting the useful information on aerosol are of great importance, especially if one takes into account the hindering effects of atmospheric background and optical noises. This paper presents a statistical approach to this problem, and the possibilities of single-frequency sounding from space are analyzed.     

Multi-computer VXIbus system set up and use

VXI has matured into a flexible bus architecture with which to develop various types of instrumentation systems. This paper details the multi-computer approach used in the VXI-based system that CACI developed for the Air Force. The system, the Engine Test/Trim Automated System II (ETTAS II) is designed to test: all Air Force jet engines. The paper discusses how to integrate multiple computers in a VXI-based system, including discussions on: setting up the computers; selecting register-based versus message-based computers; setting up and using shared-memory; defining and separating tasks for each computer. The shared memory discussion talks about different ways to structure the shared memory, including setting up a system-level “Current-Value Table” (CVT) for all instruments, as well as how other devices, including another computer can access the shared memory space. The paper shows how Commercial-Off-the-Shelf (COTS) software products NI-VXI, LabVIEW, and NI-VISA (National Instruments) can be used to satisfy all these requirements. The paper shows how the multi-computer approach can be cost-effective in many cases     

Rio de la Plata estuarine system: Relationship between river flow and frontal variability

This paper deals with the application of SeaWIFS images to characterize spatial and temporal variability of fronts in the Rio de la Plata estuarine system over the period 2000–2003. We aim to depict the relationship between river outflow and variability of fronts’ loci on monthly to ENSO-related timescales and the influence of the winds along Rio de la Plata (axial winds) on the abrupt changes in frontal dynamics over synoptic timescales. During the studied period both La Niña (July 1999–June 2000) and El Niño (April 2002–May 2003) events induced significant displacements of fronts. Three distinct fronts were analyzed between river, estuarine, coastal and marine waters of the Rio de la Plata: Main Turbidity Front, Main Marine Front, and Secondary Marine Front. Their number, location and separation seem to be mainly related to river outflow and second, to fresh (>8 m/s) axial winds. During low discharge periods (i.e. summer time and/or La Niña events) these winds induce abrupt changes in the location of fronts (100–200 km) and greater separation between them over synoptic timescale, whereas during high river discharge or ENSO years some of the variability of fronts location is explained by the river’s outflow fluctuations, especially by the high variability of the River Uruguay discharge.     

What we have not learned from the troubles with the Hubble

The Hubble space-based telescope is a great tribute to our progress in space. The ability to place an optical telescope at a significant distance from the Earth's surface, away from the interference of the planet's unsteady atmosphere, have already paid off by producing magnificent records of astronomical activities in the depths of outer space. In the past the problems with the alignment of the Hubble's optics were blamed on the manufacturers of it's optical components. The hastily set investigation concluded that the problem is a spherical aberration of the primary mirror (the primary mirror is said to be 2 microns too flat at the edges). It is suggested that the real culprit is the Parker Effect. Since the time of Galileo Galilei, all telescopes were built, aligned, and used on the Earth's surface. Hubble is the first telescope to be built and aligned on Earth for use in space. Because of this we have to consider the fundamental differences between the alignment of surface-based and space-based telescopes. For those who missed our article “The Parker Effect and Navigation in Space” published in the January issue. The Parker Effect describes the result of interaction between inertial bodies (anything that has mass) and non-inertial media (light or other E/M fields)