On the uncertainties in the measurement of absolute (true) TEC over Indian equatorial and low latitude sectors

The Indian sector encompasses the equatorial and low latitude regions where the ionosphere is highly dynamic and is characterized by the equatorial ionization anomaly (EIA) resulting in large latitudinal electron density gradients causing errors and uncertainties in the estimation of range delays in satellite based navigation systems. The diurnal and seasonal variations of standard deviations in the TEC data measured during the low sunspot period 2004–2005 at 10 different Indian stations located from equator to the anomaly crest region and beyond are examined and presented. The day-to-day variability in TEC is found to be lowest at the equatorial station and increases with latitude up to the crest region of EIA and decreases beyond.     

Shear flow energy redistribution stipulated by the internal-gravity wavy structures in the dissipative ionosphere

The linear mechanism of generation, intensification and further nonlinear dynamics of internal gravity waves (IGW) in stably stratified dissipative ionosphere with non-uniform zonal wind (shear flow) is studied. In case of the shear flows the operators of linear problem are non-selfadjoint, and the corresponding Eigen functions – nonorthogonal. Thus, canonical – modal approach is of less use studying such motions. Non-modal mathematical analysis becomes more adequate for such problems. On the basis of non-modal approach, the equations of dynamics and the energy transfer of IGW disturbances in the ionosphere with a shear flow is obtained. Exact analytical solutions of the linear as well as the nonlinear dynamic equations of the problem are built. The increment of shear instability of IGW is defined. It is revealed that the transient amplification of IGW disturbances due time does not flow exponentially, but in algebraic – power law manner. The effectiveness of the linear amplification mechanism of IGW at interaction with non-uniform zonal wind is analyzed. It is shown that at initial linear stage of evolution IGW effectively temporarily draws energy from the shear flow significantly increasing (by an order of magnitude) own amplitude and energy. With amplitude growth the nonlinear mechanism turns on and the process ends with self-organization of nonlinear solitary, strongly localized IGW vortex structures (the monopole vortex, the transverse vortex chain or the longitudinal vortex street). Accumulation of these vortices in the ionospheric medium can create the strongly turbulent state.     

Multi-Criteria Decision Analysis integrated with GIS and remote sensing for astronomical observatory site selection in Antalya province,Turkey

Astronomical observatory site selection is a complex problem that involves evaluation of multiple factors from different sources. The aim of this study is to select the best possible candidates for astronomical observations sites using Multi-Criteria Decision Analysis integrated with Geographical Information Systems and remote sensing technologies. The study was implemented in the Antalya province of Turkey, which is convenient for astronomical site observatory facilities with its appropriate climate properties and weather conditions. Eleven factors (cloud cover, precipitable water, earthquake zones, geology, landslide inventory, active fault lines, Digital Elevation Model, city lights, mining activities, settlement areas, roads) were determined, splitting into three categories; meteorological, geographical and anthropogenic criteria. These factors were evaluated using Analytical Hierarchy Process method and the weights of criteria layers were determined. As a result, the most suitable areas were located extensively in western and eastern part of Antalya. This study offers a robust, accurate, cost and time effective procedure for preliminary site selection for astronomical observatory. However, for a final decision of the best location of astronomical observatory, site testing measurements and atmospheric seeing observations will be further required in these preliminary areas.     

Ionospheric F-region response to geomagnetic disturbances

The F2-region reaction to geomagnetic storms usually called as an ionospheric storm is a rather complicated event. It consists of so called positive and negative phases, which have very complicated spatial and temporal behavior. The main morphological features of ionospheric storms and the main processes governing their behavior were understood at the end of the 1900s and described in a series of review papers. During the recent decade there were many publications dedicated to the problem of ionospheric storms. In this paper a concept of ionospheric storm morphology and physics formulated at the end of the 1990s is briefly summarized and the most interesting results obtained in the 2000s are described. It is shown that the main features of the studies of the previous decade were: the use of GPS TEC data for analyzing the ionospheric storm morphology, attraction of sophisticated theoretical models for studying the processes governing ionospheric behavior in disturbed conditions, and accent to analysis of ionospheric behavior during prominent events (very strong and great geomagnetic storms). Also a special attention was paid to the pre-storm enhancements in foF2 and TEC.     

Wireless sensor networks for planetary exploration: Experimental assessment of communication and deployment

Planetary surface exploration is an appealing application of wireless sensor networks that has been investigated in recent years by the space community, including the European Space Agency. The idea is to deploy a number of self-organizing sensor nodes forming a wireless networked architecture to provide a distributed instrument for the study and exploration of a planetary body. To explore this concept, ESA has funded the research project RF Wireless for Planetary Exploration (RF-WIPE), carried out by GMV, SUPSI and UPM. The purpose of RF-WIPE was to simulate and prototype a wireless sensor network in order to assess the potential and limitations of the technology for the purposes of planetary exploration.     

Autonomic straightening of gravitropically curved cress roots in microgravity.

The typical response of plant organs to gravistimulation is differential growth that leads to organ bending. If the gravitropic stimulus is withdrawn, endogenous compensation of the graviresponse and subsequent straightening occur in some plants. For instance, autonomic straightening of Lepidium roots occurs when gravitropically-curved rootsare rotated on a clinostat (Stankovi et al., 1998a). To determine whether endogenous compensation of the graviresponse also occurs in space, microgravity-grown cress roots were laterally centrifuged in-flight and then returned to microgravity using Biorack hardware on a shuttle mission (STS-81). The cress roots were centrifuged at 4 different g-doses (0.1 x g and 1 x g for 15 or 75 min). All four treatments yielded varying degrees of root curvature. Upon removal from the centrifuge, roots in all four treatments underwent subsequent straightening in microgravity. This straightening resulted from a loss of gravitropic curvature in older regions of the root and the coordinated alignment of new growth. These results show that both microgravity and clinostat rotation on Earth are equivalent in stimulus withdrawal with respect to the induction of endogenous compensation of the curvature. Cress roots are the only plant organ shown to undergo compensation of the curvature in both microgravity and on a clinostat. The compensation of graviresponse in space rules out the hypothesis that the endogenous root straightening ("autotropism") represents a commitment to a pre-stimulus orientation with respect to gravity and instead suggests that there is a default tendency towards axiality following a withdrawal of a g-stimulus.     

Ontogeny of plants under various gravity condition.

The results of experiments performed under conditions of microgravity (MG) or under its simulation on the horizontal clinostat (HC) with the callus, seedlings of various species and embryogenic structures have revealed a definite role of gravity as an ecological factor in the processes of cytomorphogenesis, growth, and development. The transformation of differentiated somatic cells of arabidopsis seed into undifferentiated callus was not inhibited under MG, though modifications of the whole callus morphology and of mean cell and nucleus size were observed. The morphogenesis of polar structures such as root-hair bearing cells of Lactuca primary root has been shown to be modified in the course of differentiation under mass acceleration diminished below 0.1 g. Seed germination and seedling morphogenesis under MG follow their normal course, but a significant stimulation of shoot growth with no effect on primary root growth has been determined. A successful in vitro regeneration of Nicotiana tabacum plantlets from leaf cells and subsequent formation of shoots and roots on a continuously rotating HC as well as the formation of viable seeds during seed-to-seed growth of Arabidopsis plants under MG have indicated that gravity plays but a limited role in the processes of embryogenesis and organogenesis.     

The CELSS Test Facility project: an example of a CELSS flight experiment system.

The CELSS Test Facility (CTF) is a device for measuring crop plant productivity in the micro-gravity environment of Space Station Freedom. It will allow us to address questions of crop productivity in space, versus that on the ground. The crop productivity factors that will be measured are rates of: 1) biomass production, 2) food production, 3) O2 and CO2 exchange, and 4) water transpiration. In addition, other productivity factors of specific crops will be determined, such as : 1) the ratio of edible to inedible biomass (harvest index), 2) leaf area exposed to and collecting light (leaf area index), 3) ratio of root mass to total biomass, and 4) photosynthetic efficiency (ratio of moles of CO2 fixed (or O2 produced), per mole of photons of specific energies used). Plant and crop morphology, at several levels, ranging from the community to the sub-cellular, will also be evaluated.     

The energy release of substorm and magnetic storm: Its present state and future improvements by KuaFu mission

Considering the KuaFu mission, state of the energy release of substorm and storm is simply presented and it’s improvements by KuaFu mission are investigated. The KuaFu mission will provide us an opportunity to improve our understanding of the energy release during the storm and the substorms. The two KuaFu-B satellites flying in 180° phase-lagged formation in a polar orbit will allow synoptic observations of the auroral oval, central plasma sheet, ring current and other regions. It can monitor the polar region 24/7 continuously. The advantage of the KuaFu mission is to provide the data during all phases of storm and substorm time that can be used to study the global energy release during all phases continuously. The data from auroral imager and other in-situ instruments on board KuaFu-B can be used to study the auroral dynamics and Joule heating during a storm and substorm. The data from the neutral atom imager instrument can be used to study the dynamics and the energy release in the ring current region from sudden commencement to complete storm recovery. Furthermore the data from KuaFu-A, which is around L1 point, can be used to study the interplanetary conditions along with the data from the plasma sheet to study the triggering process and energy release during a substorm. So, KuaFu mission with its continuous time monitoring facilities would enable us to make much progress towards solving the underlying problems.     

Monopolar structure of the Sun in between polar reversals and in Maunder Minimum

After a polar reversal in one hemisphere the Sun has two polar caps of the same sign, leaving it in a kind of monopolar state. It may take months before a polar reversal occurs in the other hemisphere. The situation may have been extreme in the Maunder Minimum where the northern hemisphere most probably did not have polar reversals during several cycles, while the southern hemisphere may have had some. This may affect the interplanetary field and thus the cosmic rays reaching the Earth. Using the relation between the Wolf number and the speed of the global magnetic field regions the yearly mean Wolf number has to exceed 40 in order to have polar reversals, hence per hemisphere we expect that it must exceed 20. This may be used to give a definition of a deep minimum.