Space Physics Interactive Data Resource—SPIDR

SPIDR (Space Physics Interactive Data Resource) is a standard data source for solar-terrestrial physics, functioning within the framework of the ICSU World Data Centers. It is a distributed database and application server network, built to select, visualize and model historical space weather data distributed across the Internet. SPIDR can work as a fully-functional web-application (portal) or as a grid of web-services, providing functions for other applications to access its data holdings.

The 27-Day Signal in Sunspot Number Series and the Solar Dynamo

We analyze the Wolf number daily series WN (1849 to present) as well as two other related series characterizing solar activity. Our analysis consists in computing the amplitude of a given Fourier component in a sliding time window and examining its long-term evolution. We start with the well-known 27.03- and 27.6-day periods and observe strong decadal variations of this amplitude as well as a sharp increase of the average value starting around 1905. We then consider a packet of 31 lines with periods from 25.743 to 28.453 days, which is shown to be a better representation of the synodic solar rotation. We first examine the temporal evolution of individual lines, then the energy of the packet. The energy of the packet increases sharply at the beginning of the 20th century, leading by more than two decades the well-known increase of the Wolf number. The nonaxisymmetry of sunspots increases before the total increase of activity and may be considered as a precursor. We discuss briefly and tentatively this observation in terms of solar dynamo theory.     

The oxidation state of hydrothermal systems on early Enceladus

The discovery of CO₂, CH₄, and N₂ in a plume at Enceladus provides useful clues about the chemistry and evolution of this moon of Saturn. Here, we use chemical equilibrium and kinetic calculations to estimate the oxidation state of hydrothermal systems on early Enceladus, with the assumption that the plume's composition was inherited from early hydrothermal fluids. Chemical equilibrium calculations are performed using the CO₂/CH₄ ratio in the plume, and kinetic calculations are conducted using equations from fluid dynamics and chemical kinetics. Our results suggest that chemical equilibrium between CO₂ and CH₄ would have been reachable at temperatures above ∼200 °C in hydrothermal systems. The oxidation state of the hydrothermal systems would have been close to the pyrrhotite-pyrite-magnetite (PPM) or fayalite-magnetite-quartz (FMQ) redox buffer (i.e., terrestrial-like) if the plume's CO₂ and CH₄ equilibrated in hydrothermal systems long ago. As for minerals, we suggest that iron metal would have been oxidized to magnetite by the escape of H₂ from the early satellite. Our calculations also indicate that, assuming CO₂ and CH₄ reached chemical equilibrium, magnetite would not have been oxidized to hematite in hydrothermal systems, perhaps due to insufficient H₂ escape. It is shown that, if Enceladus accreted as much NH₃ as comets contain, the presence of N₂ and deficiency of NH₃ in the plume can be understood in the context of chemical equilibrium in the C-N-O-H system. We conclude by proposing an evolutionary hypothesis in which the fairly oxidized nature of the plume can be explained by a brief episode of oxidation caused by short-lived radioactivity. These suggestions can be rigorously tested by acquiring gravity and isotopic data in the future.     

Improvements of drilling fluid processing for cable-suspended electromechanical drills

Deep ice drilling in Polar Regions plays a key role in paleo-climate, microbiological and glaciological researches. For deep ice and subglacial coring the special purpose-built electromechanical cable-suspended drills with bottom-hole circulation are designed and explored. Used at present drilling fluid circulation systems are specified by very high fluid wastes during processing. Measurements in deep drilling projects in Antarctic and Greenland ice sheets showed that 25%-40% of the drilling fluid, pumped into the hole, is retrieved to the surface with cable and drill, and up to 45% of retrieved fluid goes to waste. This leads not only to increasing of the fluid consumption and cost of the project in general but also to severe contamination of air, surface and near-surface snow-firn layers at the drilling site. In order to reduce wastes and environmental impact, it is proposed to modify drilling fluid processing system by avoiding of evaporation and leakages of fluid as far as practicable. Drilling fluid is prepared and pumped into the hole according to predetermined program on semiautomatic mode, and volume and density of blended and pumped into the hole drilling fluid are measured continuously. Components of the drilling fluid are stored and mixed in the special closed containers equipped by pressure relief valves. Separation of drilling fluid from ice cuttings is carried out by two steps: firstly, fluid is separated with hydro extractor and then with thermal separator. To reduce the amount of removed drilling fluid with cable special squeezing collar is installed on the borehole mouth. All these arrangements are able to decrease drilling fluid wastes in many times.     

Signature of long supercycles in the Pleistocene history of Asian limnic systems

The analysis of sediment chemistry and biota in drill cores from Lake Khubsugul in Mongolia (KDP-01) and Lake Baikal in Siberia (BDP-96/1), two great Eurasian freshwater lakes, detected prominent climate and biological events at 460–420 and 670 kyrs BP in addition to the orbital cycles of precession, tilt and eccentricity. The revealed long-term events were associated with notable changes in biodiversity and geography/landscapes, mainly in water budgets and weathering patterns. The span between 460–420 and 670 kyrs BP was the time when the climate and geographic conditions differed from those before and after these events. The corresponding 33–24 m (670–460 kyr) interval of the Khubsugul core lacked the usual signature of the Milankovitch glacial/interglacial cycles. Events of approximately these ages were found in some other continental ecosystems and in oceanic δ¹³C records. The two events may mark the phases of a 300–500-kyr long supercycle (or megastadial) in the evolution of continental ecosystems. Among other causes (e.g., regional tectonic events), this periodicity, being globally correlated, may be associated with the 400-kyr cycle of the Earth’s orbital eccentricity.     

Geoarchaeology of the Kostenki–Borshchevo sites,Don River Valley,Russia

The Kostenki–Borshchevo localities include 26 Upper Paleolithic sites on the first and second terraces along the west bank of the Don River, near Voronezh on the central East European Plain. Geoarchaeological research from 2001 through 2004 focused on sites Kostenki 1, 12, and 14, with additional work at Kostenki 11 and 16, and Borshchevo 5. The strata are grouped into three units (bottom up): Unit 1, > 50 ka, consists of coarse alluvium (representing upper terrace 2 deposits) and colluvium, overlain by fine‐grained sediments. Unit 2 includes archaeological horizons sealed within two sets of thin lenses of silt, carbonate, chalk fragments, and organic‐rich soils (termed the Lower Humic Bed and Upper Humic Bed) dating 50–30 ka. Separating the humic beds is a volcanic ash lens identified as the Campanian Ignimbrite Y5 tephra, dated elsewhere by Ar/Ar to ca. 40 ka. The humic beds appear to result from the complex interplay of soil formation, spring deposition, slope action, and other processes. Several horizons buried in the lower part of Unit 2 contain Upper Paleolithic assemblages. The springs and seeps, which are still present in the area today, emanated from the bedrock valley wall. Their presence may account for the unusually high concentration of Upper Paleolithic sites in this part of the central East European Plain. Unit 3, < 30 ka, contains redeposited loess with a buried soil (Gmelin Soil) overlain by a primary full‐glacial loess with an associated Chernozem (Mollisol), forming the surface of the second terrace. © 2007 Wiley Periodicals, Inc.     

Monochromatic intensity measurements of selected areas of lunar surface for possible investigations

Absolute photoelectric intensity measurements of 104 selected lunar regions are given in five interference filters 4035 Å, 4765 Å, 5538 Å, 6692 Å and 7922 Å. Among these regions, eighteen lunar regions have been measured repeatedly for several phase angles between +86° and ?43°. They include observations made very close to the full Moon. A catalogue has been compiled to serve as a basin for possible investigations of colour contrasts of lunar grounds, variation of the ratio of reflectivity with wavelengths and phase angles for morphological studies. The study can be extended for the brightness phase variation, opposition effect and radiance factors at zero phase in five colours.     

Orbital forcing of continental climate during the Pleistocene: a complete astronomically tuned climatic record from Lake Baikal, SE Siberia

A new composite BDP-96 biogenic silica record over the entire Pleistocene was generated by splicing BDP-96-1 and BDP-96-2 drill cores from Lake Baikal, crosschecked against a similar record from a nearby BDP-98 drill core. A new astronomically tuned age model is proposed based on correlating peak biogenic silica responses with the timing of September perihelia. This target is derived from analysis of regional climate proxy responses during the Holocene, the last interglacial and around paleomagnetic reversals. By resolving virtually every precessional cycle during the Pleistocene, the new age model represents a major improvement compared with previously reported Lake Baikal timescales. The astronomically tuned ages of the Pleistocene paleomagnetic reversals are consistent with published dates. The minimal tuning approach we used (precession only) has also aligned high signal power in a narrow obliquity band, confirming the strong presence of orbital forcing. There are also strong ca 100-ka scale cycles, but these are not aligned with the orbital eccentricity.Despite the location of Lake Baikal in a continental interior that is highly sensitive to insolation forcing, the tuned biogenic silica record reveals a consistent phase difference of −32° (ca 4 ka) relative to insolation in the obliquity band. An inherent lag embedded in a continental proxy record, not driven by global ice volume, is an intriguing finding. Another new observation is that long-term changes in sedimentation rates in Lake Baikal appear to be related to the amplitude of orbital forcing; both amplitudes and sedimentation rates undergo significant changes during MIS 24-MIS 19 interval corresponding to the Middle Pleistocene Transition. With potential for linking continental and marine climato-stratigraphies, the new Baikal record serves a new benchmark correlation target in continental Eurasia, as an alternative to June 65°N insolation and ODP-correlated timescales.