The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.

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Antarctic climate change and the environment

Holgate, S.J.; Matthews, A.; Woodworth, P.L.; Rickards, L.J.; Tamisiea, M.E.; Bradshaw, E.; Foden, P.R.; Gordon, K.M.; Jevrejeva, S., and Pugh, J., 2013. New data systems and products at the Permanent Service for Mean Sea Level. Sea-level rise remains one of the most pressing societal concerns relating to climate change. A significant proportion of the global population, including many of the world's large cities, are located close to the coast in potentially vulnerable regions such as river deltas. The Permanent Service for Mean Sea Level (PSMSL) continues to evolve and provide global coastal sea-level information and products that help to develop our understanding of sea-level and land motion processes. Its work aids a range of scientific research, not only in long-term change, but also in the measurement and understanding of higher frequency variability such as storm surges and tsunamis. The PSMSL has changed considerably over the past 10 years, and the aim of this paper is to update the commu...

https://bioone.org/journals/Journal-of-Coastal-Research/volume-29/issue-3/JCOASTRES-D-12-00175.1/New-Data-Systems-and-Products-at-the-Permanent-Service-for/10.2112/JCOASTRES-D-12-00175.1.pdf

New Data Systems and Products at the Permanent Service for Mean Sea Level

Understanding sea-level processes, such as ocean tides, storm surges, tsunamis, El Nino and rises caused by climate change, is key to planning effective coastal defence. Building on David Pugh's classic book Tides, Surges and Mean Sea-Level, this substantially expanded, full-colour book now incorporates major recent technological advances in the areas of satellite altimetry and other geodetic techniques (particularly GPS), tsunami science, measurement of mean sea level and analyses of extreme sea levels. The authors discuss how each surveying and measuring technique complements others in providing an understanding of present-day sea-level change and more reliable forecasts of future changes. Giving the how and the why of sea-level change on timescales from hours to centuries, this authoritative and exciting book is ideal for graduate students and researchers in oceanography, marine engineering, geodesy, marine geology, marine biology and climatology. It will also be of key interest to coastal engineers and governmental policy-makers.

Sea-Level Science: Understanding Tides, Surges, Tsunamis and Mean Sea-Level Changes

GOCE is the first gravitational gradiometry satellite mission. Gravitational gradiometry is the measurement of the second derivatives of the gravitational potential. The nine derivatives form a 3 × 3 matrix, which in geodesy is referred to as Marussi tensor. From the basic properties of the gravitational field, it follows that the matrix is symmetric and trace free. The latter property corresponds to Laplace equation, which gives the theoretical foundation of its representation in terms of spherical harmonic or Fourier series. At the same time, it provides the most powerful quality check of the actual measured gradients. GOCE gradiometry is based on the principle of differential accelerometry. As the satellite carries out a rotational motion in space, the accelerometer differences contain angular effects that must be removed. The GOCE gradiometer provides the components V
 xx
 , V
 yy
 , V
 zz
 and V
 xz
 with high precision, while the components V
 xy
 and V
 yz
 are of low precision, all expressed in the gradiometer reference frame. The best performance is achieved inside the measurement band from 5 × 10–3 to 0.1 Hz. At lower frequencies, the noise increases with 1/f and is superimposed by cyclic distortions, which are modulated from the orbit and attitude motion into the gradient measurements. Global maps with the individual components show typical patterns related to topographic and tectonic features. The maps are separated into those for ascending and those for descending tracks as the components are expressed in the instrument frame. All results are derived from the measurements of the period from November to December 2009. While the components V
 xx
 and V
 yy
 reach a noise level of about $${10\;\rm{\frac{mE}{\sqrt{Hz}}}}$$
 , that of V
 zz
 and V
 xz
 is about $${20\; \rm{\frac{mE}{\sqrt{Hz}}}}$$
 . The cause of the latter’s higher noise is not yet understood. This is also the reason why the deviation from the Laplace condition is at the $${20 \;\rm{\frac{mE}{\sqrt{Hz}}}}$$
 level instead of the originally planned $${11\;\rm{\frac{mE}{\sqrt{Hz}}}}$$
 . Each additional measurement cycle will improve the accuracy and to a smaller extent also the resolution of the spherical harmonic coefficients derived from the measured gradients.

GOCE gravitational gradiometry

Gravity field and steady-state ocean circulation mission

Dedicated gravity field missions—principles and aims

Gravity Field and Steady-State Ocean Circulation Mission

Current knowledge of the Earth's gravity field and its geoid, as derived from various observing techniques and sources, is incomplete Within a reasonable time, substantial improvement will come by exploiting new approaches based on spaceborne gravity observation Among these, the European Space Agency (ESA) Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite mission concept has been conceived and designed taking into account multi-disciplinary research objectives in solid Earth physics, oceanography and geodesy Based on the unique capability of a gravity gradiometer combined with satellite-to-satellite high-low tracking techniques, an accurate and detailed global model of the Earth's gravity field and its corresponding geoid will be recovered The importance of this is demonstrated by a series of realistic simulation experiments In particular, the quantitative impact of the new and accurate gravity field and geoid is examined in studies of tectonic composition and motion, Glaciological Isostatic Adjustment, ocean mesoscale variability, water mass transport, and unification of height systems Improved knowledge in each of these fields will also ensure the accumulation of new understanding of past and present sea-level changes

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P.L. Woodworth

Papers

Dedicated gravity field missions—principles and aims

Gravity Field and Steady-State Ocean Circulation Mission

The European Gravity Field and Steady-State Ocean Circulation Explorer Satellite Mission: Its Impact on Geophysics

European Views on Dedicated Gravity Field Missions: GRACE and GOCE

The European Earth Explorer Mission GOCE: Impact for the Geosciences