QBO of the Equatorial-Stratospheric Winds Revisited: New methods to verify the dominance of 28-month cycle

The equatorial-stratospheric wind that shows a Quasi Biennial Oscillation (22-32 months) has been revisited using a dual statistical detail regarding the search of the dominance harmonics. Data were used from the Freie Universitat of Berlin since 1953 for different heights combining the observations of the three radiosonde stations. The dominant period of 28 months has been reaffirmed but with a discernible amplitude and a phase, respectively, inversely varying with height. Such a cycle suggests an estimate for the coming easterly equatorial wind occurrence at 15 hPa level at the end of 2009. The 28-month harmonic is found to take about a year to descend from 15 to 70 hPa with a progressive lag of about 1 month/km. At the top of the stratosphere, easterlies dominate, while at the bottom, westerlies are more likely to be found. Correlation with sunspot numbers and seasonal rainfall is discussed

Bone diagenesis in a Mycenaean secondary burial (Kastrouli, Greece)

Abstract: This paper presents the characteristics of bone diagenesis in a secondary commingled Mycenaean burial in Kastrouli (Phocis, Greece) through the histological (light microscopy), physical (FTIR-ATR), and biochemical (collagen) analysis of seventeen human (including two petrous bones) and seven animal bones. Post-mortem modifications in bone microstructure, bioapatite, and collagen were characteristic of burial environments with seasonal groundwater and temperature fluctuations. The two human petrous bones displayed a lack of microscopic focal destruction (MFD) sites and a generally good histological preservation, but although a small sample size, did not show any better bioapatite and collagen preservation compared with human femora. Intra-site variations were defined by three main diagenetic patterns that display differences in histological modifications, crystallinity changes, and collagen degradation. These different patterns were either related to different microenvironment conditions and/or influenced by possible differences in the early taphonomic histories experienced by bones prior to secondary deposition. Further, this study highlights the importance of infrared splitting factor (IRSF), carbonate/phosphate ratio (C/P), and general histological index (GHI) for the qualitative assessment of archaeological bone, and the potential use of amide/phosphate ratio (Am/P) as a collagen predictor

Stable rate of slip along the Karakax section of the Altyn Tagh Fault from observation of inter-glacial and post-glacial offset morphology and surface dating

Digital elevation maps obtained using TanDEM‐X and Pleiades data combined with newly obtained surface age estimates using Cosmogenic Radionuclide (CRN) and Optically Simulated Luminescence (OSL) methods are used to quantify the slip‐rate along the western section of the Altyn Tagh fault in southern Xinjiang. The reconstruction of the conical shape of massive alluvial fans inferred to be from the Eemian (115±7 ka) from CRN dating shows consistent left‐lateral offsets of 300±20 m, yielding a slip rate of 2.6±0.3 mm/yr. Successive episodes of incision have left cut terraces inset in wide canyons, 10‐25 m below the fans' surface. The incision was followed by the deposition of a broad terrace of early Holocene age, which is re‐incised by modern stream channels. Near the village of Shanxili, a 200 m‐wide valley is partially dammed by a shutter ridge displaced by the fault. A fill terrace deposited upstream from the ridge has an OSL age of.8±0.6 ka. The 23±2 m offset of the riser incising the terrace indicates a minimum post‐depositional movement on the fault, yielding a Holocene rate of 2.6±0.5 mm/yr, consistent with the 115 ka‐average slip rate. Scarp degradation analysis using mass diffusion reveals a non‐linear relationship between fault displacement and degradation coefficient along the progressively exposed fault scarp, a pattern suggesting either seismic clustering or variable diffusion rate since the Eemian. Together with the Gozha Co‐Longmu Co fault to the south, the Karakax section of the Altyn Tagh Fault contributes to the eastward movement of the western corner of Tibet

The genetic history of the Southern Arc: a bridge between West Asia and Europe

By sequencing 727 ancient individuals from the Southern Arc (Anatolia and its neighbors in Southeastern Europe and West Asia) over 10,000 years, we contextualize its Chalcolithic period and Bronze Age (about 5000 to 1000 BCE), when extensive gene flow entangled it with the Eurasian steppe. Two streams of migration transmitted Caucasus and Anatolian/Levantine ancestry northward, and the Yamnaya pastoralists, formed on the steppe, then spread southward into the Balkans and across the Caucasus into Armenia, where they left numerous patrilineal descendants. Anatolia was transformed by intra–West Asian gene flow, with negligible impact of the later Yamnaya migrations. This contrasts with all other regions where Indo-European languages were spoken, suggesting that the homeland of the Indo-Anatolian language family was in West Asia, with only secondary dispersals of non-Anatolian Indo-Europeans from the steppe

QBO of the Equatorial-Stratospheric Winds Revisited: New Methods to Verify the Dominance of 28-Month Cycle

The equatorial-stratospheric wind that shows a Quasi Biennial Oscillation (22–32 months) has been revisited using a dual statistical detail regarding the search of the dominance harmonics. Data were used from the Freie Universitat of Berlin since 1953 for different heights combining the observations of the three radiosonde stations. The dominant period of 28 months has been reaffirmed but with a discernible amplitude and a phase, respectively, inversely varying with height. Such a cycle suggests an estimate for the coming easterly equatorial wind occurrence at 15 hPa level at the end of 2009. The 28-month harmonic is found to take about a year to descend from 15 to 70 hPa with a progressive lag of about 1 month/km. At the top of the stratosphere, easterlies dominate, while at the bottom, westerlies are more likely to be found. Correlation with sunspot numbers and seasonal rainfall is discussed

Periodic variation of δ18O values from V28-239 pacific ocean deep-sea core

Spectral analysis of δ18O values from V28-239 pacific ocean deep-sea core has revealed periodicities which correspond to those calculated for the eccentricity (400 and 100 Kyrs), the obliquity (41 Kyrs) and the climatic precession (23 and 19 Kyrs) as well as secondary ones spanning between 16 Kyrs to 1 million years. The methods of spectrum analysis applied were the maximum entropy, fourier and the successive approximations, where the periodicities are located and their amplitude defined. The significance and stationarity of the detected periods was examined by various tests as well as employing an evolutionary pseudosonogram. The dominant 100 Kyrs and 50 Kyrs periods are present throughout all the interval, the 30 Kyrs is at low variance during 1.2 to 2 million years interval, the precessional signal is not stationary and appears at about 600 Kyrs to 1820 Kyrs. This study shows the necessity of applying various spectral analysis techniques and several tests to extract the optimum of spectral information and also to test the stationarity of certain periodicities, especially when implied mechanisms of climatic cause and variability are involved. © 1995 Kluwer Academic Publishers

A statistical reappraisal in the relationship between global and Greek seismic activity

For the period 1917-1987, Greek seismic activity exhibits a very significant positive correlation to the preceding global activity with a time-lag of 15 years. It seems that all Greece and the two characteristic areas in which we have separated it (Greece without Arc, and the area of the Greek seismic Arc), follow the global seismic activity but with a time-shift of 15 years. Moreover, it seems to exist an intrinsic interaction mechanism between the Greek seismic arc and the rest of Greece, which may be deduced by their different behavior exhibited when they are correlated with the global activity, as well as from the correlation between themselves, where a very significant positive correlation has been found with a time-lag of 3 years, for Greece without arc preceding. A quasi-periodic term of 30-yrs is also observed in these detailed four seismic time-series. The cross-correlation analysis of seismic time-series, as shown, is served as a powerful tool to clarify the complicated space-time pattern of the world wide mosaic of tectonic plate motions. The implications of spring-block model of tectonic plates interaction is invoked, considering the earth's rotation rate changes as their triggering agent. Particular emphasis is given to the potential of such studies in earthquake prediction efforts from local or regional scales to a global scale and vice-versa. © 1995 Kluwer Academic Publishers

On the 60-month cycle of multivariate ENSO index

Many point indices have been developed to describe El Niño/Southern Oscillation but the Multivariate El Niño Southern Oscillation (ENSO) Index (MEI) is considered the most representative since it links six different meteorological parameters measured over the tropical Pacific. Spectral analysis with appropriate data reduction techniques of monthly values of MEI (1950-2008) has allowed the identification of a large 60-month cycle, statistically confident at a level larger than 99%. The highest values of MEI (typical of El Niño events) and the lowest values of MEI (typical of La Niña events) are concordant with respective maxima and minima values of the identified 60-month cycle