Essex Rock

All landscapes are built on rock: from hard stone for building with, to the softest clay or sand. Each piece of rock is a storehouse of prehistorical information; even a simple pebble from the garden has its own complex tale to tell. Geology is the great detective science that can unlock these secrets. In this entertaining and eye-opening book, the authors take a deep dive – quite literally – into their home county of Essex. We are all living in an ice age, an ongoing event that has hugely affected Essex over the last 3 million years. Yet this county was born more than 500 million years ago. Our story begins when the land we know as Essex was part of a large continent close to the South Pole, tracing the geological processes that continue to shape the countryside around us. The form of the land, boulders on village greens, road cuttings, cliffs, stones in church walls – they can all bring geology to light in unexpected and fascinating ways. Aimed at a general readership with no scientific background, chapters progress from fundamentals to intricate details of geological investigations and cutting-edge research. Richly illustrated with photographs and colour diagrams, here the geology of a county is visualised and brought to life as never before, along with pertinent environmental insights in the light of climate change that is happening now.

Antarctic ozone recovery

Since 1976, and more so since 1985, the Antarctic ozone level has suffered considerable depletion (termed as Antarctic ozone hole), attributed to the destructive effects of CFC compounds leaking into the atmosphere from man-made gadgets. The 12-month running means of South Pole Dobson ozone (monthly means, upto 1999 end only) were subjected to spectral analysis, which showed considerable, significant amplitudes for QBO (Quasi-biennial, 2-3 years) and QTO (Quasi-triennial, 3-4 years) oscillations, with a total range of 20-30 DU. When subtracted from the original values, a fairly smooth variation was seen, with a decrease from ~260 DU in 1986 to ~230 DU in 1996 (~12% decrease in 12-month running means), and an almost steady level thereafter. Thus, the net ozone variation at South Pole consists of two parts, (i) a long-term monotonically downward trend upto 1996 and a steady level thereafter and (ii) a superposed QBO-QTO oscillation. The chemical destruction effect is not likely to disappear soon, and may even increase if greenhouse effects, major volcanic eruptions or enhanced stratospheric cooling intervene. If the long-term level (i) remains steady, an extrapolation of the QBO-QTO patterns indicates that the ozone level is due for an increase from about 1999 end to about 2001 beginning. The purpose of the present analysis is to point out that, if such an increase of 20-30 DU occurs, it should not be misinterpreted as due to a decrease in chemical destruction, which scientists are eagerly awaiting due to the indication of a reduction in the halogen load in recent years due to adherence to the Montreal Protocol. After one or two years (in 2002), the extrapolated QBO-QTO oscillation may bring down the ozone level back again to the 1999 end level, and the apparent recovery may turn out to be a false signal.

Non-uniform dissipation of the Antarctic ozone hole

The evolution o f the Antarct ic ozone hole is illustrated fo r 1985·1989 and 1990 springs.A detailed study for 1986.19 89 and 1990 events indicates that the evolution. which occurs in ea rly October . isfairly unifo rm over the South Pole. Hence the fluctuations observed at Syowa, McMurdo and Palmer duringthis period arc mostly due to the vortex \''3.11 passing in and out over these periferial loca t ions. However, later inNovember when the hole is dissipating, the vortex may shift from the South Pole in any direction and may alsocome back or intensify on Sou th Pole before finally disappearing. At South Pole. the recovery started by Octoberend in 19S5. 19R6 and 1988 but later in 19R7 (November end), 1989 {November beginning) and 1990 (Novemberend •.

An Investigation of Extreme Cold Events at the South Pole

From 5 July to 11 September 2012, the Amundsen-Scott South Pole station experienced an unprecedented 78 days in a row with a maximum temperature at or below -50°C. Aircraft and ground-based activity cannot function without risk below this temperature. Lengthy periods of extreme cold temperatures are characterized by a drop in pressure of around 15 hPa over four days, accompanied by winds from grid east. Periodic influxes of warm air from the Weddell Sea raise the temperature as the wind shifts to grid north. The end of the event occurs when the temperature increase is enough to move past the -50°C threshold. This study also examines the length of extreme cold periods. The number of days below -50°C in early winter has been decreasing since 1999, and this trend is statistically significant at the 5% level. Late winter shows an increase in the number of days below -50°C for the same period, but this trend is not statistically significant. Changes in the Southern Annular Mode, El Niño Southern Oscillation, and the Interdecadal Pacific Oscillation/Tripole Index are investigated in relation to the initiation of extreme cold events. None of the correlations are statistically significant. A positive Southern Annular Mode and a La Niña event or a central Pacific El Niño Southern Oscillation pattern would position the upper-level circulation to favor a strong, symmetrical polar vortex with strong westerlies over the Southern Ocean, leading to a cold pattern over the South Pole.

Sensitivity of multi-PMT optical modules in Antarctic ice to supernova neutrinos of MeV energy

New optical sensors with a segmented photosensitive area are being developed for the next generation of neutrino telescopes at the South Pole. In addition to increasing sensitivity to high-energy astrophysical neutrinos, we show that this will also lead to a significant improvement in sensitivity to MeV neutrinos, such as those produced in core-collapse supernovae (CCSN). These low-energy neutrinos can provide a detailed picture of the events after stellar core collapse, testing our understanding of these violent explosions. We present studies on the event-based detection of MeV neutrinos with a segmented sensor and, for the first time, the potential of a corresponding detector in the deep ice at the South Pole for the detection of extra-galactic CCSN. We find that exploiting temporal coincidences between signals in different photocathode segments, a $$27\ \mathrm {M}_{\odot }$$ 27 M ⊙ progenitor mass CCSN can be detected up to a distance of 341 kpc with a false detection rate of $${0.01}\,\hbox {year}^{-1}$$ 0.01 year - 1 with a detector consisting of 10,000 sensors. Increasing the number of sensors to 20,000 and reducing the optical background by a factor of 70 expands the range such that a CCSN detection rate of 0.1 per year is achieved, while keeping the false detection rate at $${0.01}\,{\hbox {year}^{-1}}$$ 0.01 year - 1 .