Sidereal Years Research Articles

English

Properly organized data is vital for appropriate statistics and theories. In this study, it was hypothesized that raw tropical cyclone (TC) data labeled with the current Gregorian time system, dampened the dominant signals and order in the data. Therefore, the objective of this study was to explore and reorganize the data, using the TianGan-DiZhi (T-D) calendar. All 6 h TC records in 60 sidereal years over the western North Pacific (WNP) were investigated after the data were transferred from the Gregorian to T-D calendar. TianGan and DiZhi, two collections of elements in the T-D calendar, were then quantified to conduct correlation analyses with different TC parameters. The results showed significant temporal and spatial correlation between 6 h TC records and variables in the T-D calendar over different timescales. Temporally, 6 h TC records in the T-D summer, generally from May 5 to August 6, of the 60 sidereal years were significantly correlated with the strength difference between yearly TianGan and yearly DiZhi for the sidereal years. Spatially, the longitudes and latitudes of 6 h TC records were also significantly correlated with daily variables in the T-D calendar. We conclude that, TC data over the WNP can be better interpreted using the quantified T-D calendar than the Gregorian calendar. Since this ancient time-labeling tool can provide properly organized data, it might be used to modify some inputs in current numerical models to improve forecasting power. Key words: Tropical cyclone, frequency, temporal, sidereal, Gan-Zhi, calendar.

Unruly Sun: Solar Tables and Calculations in the Papyrus P. Fouad 267 A

The recently published papyrus P. Fouad inv. 267 A, dating from around the second half of the second century a.d., contains instructions and examples for the computation of the Sun’s longitude and related quantities using lost tables that were different in structure and theory from Ptolemy’s. The mean motion tables reflect knowledge of precession and a period of 37,500 Egyptian years which was assumed to exactly comprise whole numbers plus simple fractions of tropical and sidereal years as well as a third kind of year whose astronomical meaning is obscure. The equation table was based on the same solar eccentricity as in Ptolemy’s model, but a different apsidal line that was either sidereally fixed or, paradoxically, both tropically and sidereally fixed. By contrast, the tables for spherical astronomy appear to be different from Ptolemy’s primarily in details of format. This article offers a more linear presentation of the key findings of the papyrus’ editors, with additional analysis.

New cetacean ΔR values for Arctic North America and their implications for marine-mammal-based palaeoenvironmental reconstructions

Radiocarbon-dated marine mammal remains from emergent Arctic coastlines have frequently been used to reconstruct Holocene sea-ice histories. The use of such reconstructions has hitherto been complicated by uncertain marine reservoir corrections precluding meaningful intercomparisons with data reported in calibrated or sidereal years. Based on an exhaustive compilation of previously published marine mammal radiocarbon dates (both live-harvested materials and subfossils) from the Canadian Arctic Archipelago (CAA), new, statistically-derived δ13C and ΔR values are provided. Average δ13C values are: −16.1 ± 1.1‰ (bone collagen; n = 193) for bowhead (Balaena mysticetus); −14.4 ± 0.5‰ (n = 44; dentine) for beluga (Delphinapterus leucas); −14.8 ± 1.9‰ (teeth and tusks; n = 18) and −18.0 ± 4.7‰ (n = 9; bone collagen) for walrus (Odobenus rosmarus). ΔR values are 170 ± 95 14C years for bowhead (n = 23) and 240 ± 60 14C years for beluga (n = 12). Scarce data preclude calculation of meaningful, statistically robust walrus ΔR. Using the new ΔR values, an expanded and revised database of calibrated bowhead dates (651 dates; many used in previous CAA sea-ice reconstructions) shows pronounced late Quaternary spatio-temporal fluctuations in bone abundance. Though broadly resembling earlier bowhead subfossil frequency data, analysis of the new expanded database suggests early- and mid-Holocene increases in whale abundance to be of longer duration and lower amplitude than previously considered. A more even and persistent spread of infrequent low-abundance remains during “whale free” intervals is also seen. The dominance of three eastern regions (Prince Regent Inlet & Gulf of Boothia; Admiralty Inlet; Berlinguet Inlet/Bernier Bay) in the CAA data, collectively contributing up to 88% of all subfossil remains in the mid-Holocene, is notable. An analysis of calibrated regional sea-level index points suggests that severance of the Admiralty Inlet-Gulf of Boothia marine channel due to isostatically-driven regression may have played a significant role in enhanced whale mortality during this interval. Comparisons between the newly calibrated bowhead data and other regional sea-ice proxy data further highlight spatial and temporal discrepancies, potentially due to regional asynchronicities and variable sensitivities in proxy response to climate and oceanographic forcing. However, the limited number of deglacial–postglacial marine records continues to hamper extensive intercomparisons between marine mammal and other proxy datasets. Nevertheless, an examination of assumptions inherent in linking bowhead subfossil frequencies, population densities, and sea-ice thickness and distribution, shows that such relationships are highly complex. Factors such as broad sea-ice preferences, variable mortality rates and causes, long distance carcass transport, variable coastline and basin/channel geometries, and changing emergence rates all complicate the correlation of whale bone abundance to sea-ice histories.

Towards improved empirical isobase models of Holocene land uplift for mainland Scotland, UK

A new approach to modelling patterns of glacio-isostatic land uplift during the Holocene in mainland Scotland, UK, is described. The approach is based upon altitude measurements at the inner margin or locally highest point of raised estuarine surfaces dated by radiocarbon assay supported by microfossil analyses. 2,241 altitudes have been analysed by a technique new to studies of former sea-levels, Gaussian Trend Surface Analysis, and isobase models for four Holocene shorelines: the Holocene Storegga Slide tsunami shoreline, abandoned rapidly circa 7,900 sidereal years BP; the Main Postglacial shoreline, abandoned during circa 6,400-7,700 sidereal years BP; the Blairdrummond shoreline, abandoned during circa 4,500-5,800 sidereal years BP, and a speculative fourth shoreline, the Wigtown shoreline, abandoned during circa 1,520-3,700 sidereal years BP, are shown in a series of maps. The implications of the shoreline patterns for glaicio-isostasy in the area are discussed. It is maintained that the statistical technique used enables broad estimates to be made of near shore sea surface change.

Laminated sediments, human impact, and a multivariate approach: a case study in linking palynology and archaeology (Steisslingen, Southwest Germany)

Situated in the Alpine Foreland, Lake Steisslingen provides sediments covering the last 16,000 sidereal years. The exceptional value as an environmental archive is due to large laminated sections, found in several long cores. Counting of organic varves allowed the establishment of a detailed varve-based age model. A high-resolution pollen analysis for the period 5457 BC to 813 AD was carried out and compared with an archaeological mapping of a 5 km radius around Lake Steisslingen. The combined interpretation of the palynological and archaeological evidence facilitates a reconstruction of the settlement history and the evolution of the landscape over the last eight millenia. Several important aspects of vegetational and settlement history are illuminated: The mathematical ordination method of correspondence analysis is used to extract the main dimension of explanation from the pollen data. A single curve is generated and thought to reflect human impact. The validity of this assumed proxy is tested against the vegetational and archaeological evidence of the micro-scale area since Neolithic times. From the Steisslingen example, we conclude that human impact is the most important and, in a mathematical sense, continuous factor in vegetational development of those landscapes, which are settled since prehistoric times.

Observations of the Leonids over the Last Millenium

The recognition of the astronomical origin of meteors is intimately connected to the Leonid meteors, and their tendency to “storm” with a period of 33 years. It was the Leonid storm of 1799, observed by Alexander von Humboldt among others, that first established the geographical extent of the phenomenon, with observations reported over 90 degrees of longitude and 60 degrees of latitude. During the 1833 storm, Olmsted (1834) at Yale and Twining (1834) at West Point established the radiant point in Leo, and the cosmic origin was clinched when H. A. Newton (1863), also at Yale, determined that the cycle repeated in intervals of sidereal years, not tropical years. Inspired by the 1866 storm, Adams (1866), Schiaparelli (1867), and Le Verrier (1867) determined a 33.25 year period and other orbital elements for the meteor stream; two years after the discovery of Comet Tempel-Tuttle in 1865, that comet was recognized as the parent body of the Leonid stream after von Oppolzer (1867) calculated a period of 33.17 years for the comet. Astronomers confidently predicted another storm in 1899, but none appeared, though there were good showers in 1901-1903. The years 1930-32 also brought fairly good showers, but 1966 brought the strongest storm witnessed in modern times, with an estimated 100,000 meteors per hour. Steady progress was made in meteor studies in the 20th century, especially with new photographic and radar techniques. The current question is what will happen in the 1997-1999 period; the only certainty is that the event will be studied with an even wider array of techniques.

Calibration of the 14C Time Scale Beyond 22,000 BP

The conventional 14C time scale between 11,500 and 22,000 sidereal years has been calibrated by TIMS U/Th dates for corals. Only a few studies have been made for the time beyond this range. Obtaining samples suitable for numerical dating or estimating the reservoir correction of the 14C dates has been difficult, but we do not have these problems with TIMS U/Th dating of interstadial and interglacial lignite, because reservoir corrections are unnecessary.

A new sea-level curve from Nova Scotia: evidence for a rapid acceleration of sea-level rise in the late mid-Holocene

A new late Holocene sea-level curve is presented from the Atlantic coast of Nova Scotia. Contrary to earlier data from the same area, this curve starts at 4400 sidereal years before present (BP) and shows a rapid acceleration between 4400 and 3800 BP, which coincides with a similar acceleration already reported from the Northumberland Strait (Nova Scotia) and an oscillation observed in South Carolina. Comparing the two Nova Scotia curves suggests that the acceleration lasts just over 1000 years and has a vertical extent of 10 m. One puzzling fact is that the 10 m vertical extent in Nova Scotia is 8 m more than the same event measured in South Carolina and it cannot be accounted for simply by postglacial isostatic depression, since that occurs on a much longer time scale. A closer examination of most of the sea-level curves from northeastern North America reveals that either the record is missing from this interval or it is inconsistent. We suggest that this acceleration is part of a global response that coincides with the end of the mid-Holocene warming period, possibly indicating a lag response between warming and ice melt.

Radiocarbon vs. calendar ages of major lateglacial hydrological events in North America

The age of late Quaternary events has largely been established by radiocarbon dating, which does not directly measure calendar (sidereal) years because the production of 14C in the atmosphere has varied through time. Recent research allows the radiocarbon time scale to be converted to sidereal years back as far as the last deglacial period. The calibration curve of Stuiver and Reimer (1993, Radiocarbon, 35, 215–230) is presented and used to determine the true calendar age of several major lateglacial hydrological events in North America and to illustrate how the actual length of these events may substantially deviate from those calculated in radiocarbon years.

Tidal wetland record of holocene sea-level movements and climate history

Paleontological, geochemical, and lithological indicators of former marine and nonmarine influence are correlated between 13 cores from a tidal wetland (Wolfe Glade) on the southeast coast of Delaware Bay. Twenty new radiocarbon dates are used to establish the chronostratigraphy of marsh facies. Sediment iron content, weight loss on ignition, and remains of plants, diatoms and foraminifera (known to tolerate specific tidal inundation cycles) are used to describe cored facies originating from supratidal, intertidal and subtidal salt marsh subenvironments. Pollen assemblages are used to infer local Holocene climate fluctuations and to reconstruct paleoenvironments during marsh evolution. The record of paleoclimatology suggests the Atlantic Chron was warm with variable humidity in the region, whereas the Subboreal was dominated by cool and humid conditions. The Subatlantic was warmer, and initially dryer, with a cool humid phase prior to about 1 ka, returning to warmer, humid conditions in the last several centuries. Local relative sea-level movements are characterized by five rapid, short-term episodes when the rate of sea-level rise accelerated relative to the rate of marsh aggradation. These episodes are recorded by transgressive facies contacts at 5.3 ± 0.2 ka, 4.4 ± 0.2 ka, 3.25 ± 0.2 ka, and 1.8 ± 0.2 ka, sidereal years. An earlier transgressive facies contact dated 6.9 ± 0.2 ka is probably not the product of a true sea-level movement. Sea-level movements are recorded throughout the marsh as palustrine or high marsh peats or peaty overlain by lower intertidal or subtidal marine deposits. Several features suggest that these episodes are local relative transgressions produced by short-term accelerations in the rate of sea-level rise relative to marsh aggradation: the contemporaneity and apparent suddenness of marine inundations: the sequence of facies indicating marine drowning; the presence of similar events in marshes elsewhere in Delaware Bay; and the marsh-wide extent of indicative facies transitions. We propose that the rapid and frequent sea-level movements observed in Wolfe Glade are the result of surges and relaxations in the Gulf Stream (and associated spin-up and partial collapse of the North Atlantic gyre) in response to winds generated by changes in the North Atlantic atmospheric thermal gradient associated with Holocene climate fluctuations.

The present rate of uplift of Fennoscandia implies a low‐viscosity asthenosphere

ABSTRACTThe rate of displacement in Fennoscandia has been intensively discussed for many years. It is now widely accepted to be an isostatic response of the glacial history of the area.The Earth's present response to deglaciation in Fennoscandia is simulated using a three‐dimensional (3D), viscoelastic model in which the asthenosphere and mantle viscosity are allowed to vary so that the maximum rate of present uplift matches its observed value. The deglaciation history is considered to be known, and the C14‐datings are converted to sidereal years. The pattern of the present uplift gives a firm match with the observed data when a low‐viscosity asthenosphere is introduced. Assuming a 15,000 years load cycle, i.e. the glacier was applied to the surface for 15,000 years before the melting started, the best fitting earth viscosity model is a 1024 Nm lithosphere overlying a 75 km‐thick 2.0 × 1019 Pas asthenosphere and a 1.2 × 1021 Pas mantle. The simulations suggest a remaining maximum uplift of 40 m.

Eustatic changes during the last 8,000 years in view of radiocarbon calibration and new information from the Kattegatt region and other northwestern European coastal areas

In view of the calibration of the non-absolute radiocarbon chronology and the accumulation of new field data and radiocarbon dates, the calculated eustatic and isostatic factors responsible for the shore-level displacement in the Kattegatt region are revised for the period covering the last 8,000 sidereal years. The revision does not lead to any drastic changes: some levels are changed by some decimeters and the age of the transgression maximum PTM-7 is now regarded as younger than previously considered. The revised eustatic curve agrees (even in details) very well with all northwestern European relative sea-level records. The tidal effect in the Kattegatt is less than 1 dm. Possible meteorological influences cannot yet be accounted for. The Kattegatt record can be used to test local relative sea-level curves and supposed eustatic curves. Considering possible horizontal and vertical changes of the main geoid pattern, and other factors influencing the surface distribution of the ocean water, regional eustasy (like the present NW European curve) may not be globally valid in detail. The eustatic amplitude variations reflect the Earth's glacial history. The transgression/regression sequence reflects cyclic variations in the world climate of irregular frequency.

Neotectonic rates in the central Ryukyu Islands derived from 230Th coral ages

Kikai, Amami, Toku, Okierabu and Yoron Islands in the Ryukyu island arc north of Okinawa show differing rates of vertical displacement during the past 130,000 years. Kikai has been rising at a rate of 1–2 m/10 3 years over this period whereas the other islands show either recent submergence at a rate of 0.7 m/10 3 years or little movement during the last 6,000 sidereal years. A structural axis probably exists between Kikai, the outermost island in the central segment of the Ryukyu Arc, and the four inner islands. Both the coralliferous nature of the limestone units on Kikai and 230Th growth method ages of individual corals indicate that the limestone units were deposited during interglacial stages. Dated limestones from Kikai are the: 1. ( 1) Raised Coral Reef Limestone; average age of 3 samples is 5,600 years. 2. ( 2) Araki Limestone; average age of 5 samples is 42,000 years. 3. ( 3) Riukiu Limestone (younger member); average age of 3 samples is 67,000 years. The age of the older member of the Riukiu Limestone is geologically inferred to be approximately 130,000 years, which correlates with the Barbados III terrace of Broecker et al. (1968). The rates of vertical displacement of Kikai compare closely to other rates determined for post-Miocene movement in the main islands of Japan.

Florida Submergence Curve Revised: Its Relation to Coastal Sedimentation Rates

New data substantiate as well as modify the south Florida submergence curve, which indicates that eustatic sea level has risen continuously, although at a generally decreasing rate, during the last 6500 to 7000 sidereal years (5500 standard radiocarbon years) to reach its present position. Accumulation rates of coastal deposits are similar to the rate of sea-level rise, thus supporting the generalization that submergence rates largely determine as well as limit rates of coastal sedimentation in lagoonal and estuarine areas.