In addition to its application in radiocarbon dating, AMS also led to a breakthrough in application of other cosmogenic isotopic systems (10Be, 26Al) to understand various earth surface processes (e.g., glacial retreats, denudation rates). However, with the introduction and development of Accelerator Mass spectrometry (AMS), it became possible to date these natural archives with a much smaller sample quantity. Previously, conventional β counting method for radiocarbon dating required ∼1 g of carbon extracted from the samples. Radiocarbon (14C) dating has been frequently used to date recent archives. In the present attempt, we have focussed on providing an overview of frequently used radiometric (10Be, 14C, 26Al, 137Cs, 210Pb,) dating techniques and the associated instrumental developments. Radiometric dating of Quaternary samples/archives have extensively progressed due to significant instrumentation developments.

Various dating techniques applicable through the Quaternary have received significant impetus from the paleoclimate community for high-resolution paleoclimatic reconstructions that are supported by solid chronological controls. Reliable estimation of ages and temporal correlations through the Quaternary Period (<2.58 Myr) have led to a better understanding of past paleoclimatic changes. The root mean square errors of the analyzed concentrations on day 1000 decreased by the factors varying from 3 to 4 in different DA scenarios as compared to the simulation without DA. In all cases, data assimilation gradually brought ensemble-averaged concentration fields close to the true distribution. Different DA scenarios were considered with different topologies of measurement networks and different source locations.

Due to the high inhomogeneity of the concentration fields, the free regularization parameter had to be defined and tuned using the L-curve approach. The ensemble member with the maximum deviation from the unperturbed concentration distribution was selected to be used as “truth” in data assimilation experiments. On day 1000 of the simulation, correlation coefficients of the members of the concentration ensemble and the unperturbed concentration distribution fell to 0.087. The velocity fields obtained from the ensemble of stream functions were then used for the calculation of the ensemble of concentration fields following short-duration point release. The wind stress curl in the right-hand side of the equation for stream function was randomly perturbed to generate an ensemble of the perturbed fields of currents. The method was tested in an idealized setting where the contaminant was released in the ocean described by a simple linear Stommel model that includes the main features of two-dimensional (2D) wind-driven circulation in the ocean on the β-plane. The original Drifter has since gone into a deep slumber somewhere, slowly gathering strength by eating at the land of Godville, but his fragments still roam the earth looking for heroes to kill and taverns to smash.The capabilities of the ensemble Kalman filter (EKF) data assimilation (DA) method to reduce errors in simulations of concentration distributions following the accidental release of a contaminant in the ocean were evaluated. Since then, the Continental Drifter and hero-kind have been at odds with each other. The Continental Drifter, who was nearby, saw this and flew into a great rage, crashing the party and killing all the passed out heroes and heroines. But after he drifted apart, one of his ‘children’ was brutally smashed apart by a drunk group of party goers.

Once upon a time, the Continental Drifter was merciful and did not kill heroes instead making them promise never to hurt any of its kind again. Long ago, each of his steps could cause coastlines to sink into the ocean, and new mountains to erupt, but now he can only move each part of the earth some millimeters per year, as he himself has slowly drifted apart, creating many smaller, weaker Continental Drifters, leaving the original much smaller, only around the size of a small tavern. The Continental Drifter is a monster rumored to have the power of moving continents.

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