Not exact matches
Researchers from the University
of Southampton, the National Oceanography Centre and the Australian National University developed a new method for determining
sea -
level and deep -
sea temperature
variability over the past 5.3 million years.
«The important point here is that smooth projections
of sea level rise do not capture this
variability, so adverse effects
of sea level rise may occur before they are predicted to happen,» Dutton said.
The centre runs research programmes in climate
variability and change, the monitoring
of sea levels, ocean uptake
of carbon dioxide, and Antarctic marine ecosystems.
Episodes like volcanic eruptions can create
variability: the eruption
of Mount Pinatubo in 1991 decreased global mean
sea level just before the Topex / Poseidon satellite launch, for example.
In the past 15 years, the oceans have warmed, the amount
of snow and ice has diminished and
sea levels have risen, explains Lisa Goddard, an expert in climate
variability at Columbia University.
The CTD sections show that the deeper layers are also warmer and slightly saltier and the observed
sea level can be explained by steric expansion over the upper 2000 m. ENSO
variability impacts on the northern part
of the section, and a simple Sverdrup transport model shows how large - scale changes in the wind forcing, related to the Southern Annular Mode, may contribute to the deeper warming to the south.
Abstract: Mid - to late - Holocene
sea -
level records from low - latitude regions serve as an important baseline
of natural
variability in
sea level and global ice volume prior to the Anthropocene.
Suzuki, T., et al., 2005: Projection
of future
sea level and its
variability in a high - resolution climate model: Ocean processes and Greenland and Antarctic ice - melt contributions.
«The impacts
of sea level change will be felt most acutely during periods
of high
sea level, both from this type
of interannual (and decadal)
variability as well as extreme events,» Church said.
For birds and amphibians, we considered exposure to five components
of climate change, namely changes in mean temperature, temperature
variability, mean precipitation, precipitation
variability and
sea level rise.
The imprint
of SAM
variability on the Southern Ocean system is observed as a coherent
sea level response around Antarctica (Aoki, 2002; Hughes et al., 2003) and by its regulation
of Antarctic Circumpolar Current flow through the Drake Passage (Meredith et al., 2004).
«[B] y making use
of 21 CMIP5 coupled climate models, we study the contribution
of external forcing to the Pacific Ocean regional
sea level variability over 1993 — 2013, and show that according to climate models, externally forced and thereby the anthropogenic
sea level fingerprint on regional
sea level trends in the tropical Pacific is still too small to be observable by satellite altimetry.»
Our framework links innovative approaches for (1) generating high - resolution, probabilistic projection
of future climate and
sea -
level changes and (2) empirically identifying robust statistical relationships characterizing how humans have responded to past climate
variability and past climate change, in order to (3) project how humans may respond to uncertain future changes.
There is nothing there beyond the regular short - term
variability primarily due to ENSO, and
of course we should smooth enough to get rid
of this short - term
variability when testing for the kind
of long - term linkage between global temperature and
sea level that we expect.
Periods that are
of possibly the most interest for testing sensitivities associated with uncertainties in future projections are the mid-Holocene (for tropical rainfall,
sea ice), the 8.2 kyr event (for the ocean thermohaline circulation), the last two millennia (for decadal / multi-decadal
variability), the last interglacial (for ice sheets /
sea level) etc..
Zhang, J., M. Steele, and A. Schweiger (2010), Arctic
sea ice response to atmospheric forcings with varying
levels of anthropogenic warming and climate
variability, Geophys.
Mike's work, like that
of previous award winners, is diverse, and includes pioneering and highly cited work in time series analysis (an elegant use
of Thomson's multitaper spectral analysis approach to detect spatiotemporal oscillations in the climate record and methods for smoothing temporal data), decadal climate
variability (the term «Atlantic Multidecadal Oscillation» or «AMO» was coined by Mike in an interview with Science's Richard Kerr about a paper he had published with Tom Delworth
of GFDL showing evidence in both climate model simulations and observational data for a 50 - 70 year oscillation in the climate system; significantly Mike also published work with Kerry Emanuel in 2006 showing that the AMO concept has been overstated as regards its role in 20th century tropical Atlantic SST changes, a finding recently reaffirmed by a study published in Nature), in showing how changes in radiative forcing from volcanoes can affect ENSO, in examining the role
of solar variations in explaining the pattern
of the Medieval Climate Anomaly and Little Ice Age, the relationship between the climate changes
of past centuries and phenomena such as Atlantic tropical cyclones and global
sea level, and even a bit
of work in atmospheric chemistry (an analysis
of beryllium - 7 measurements).
Geoff Beacon, before betting too much check papers like Zhang et al. «Arctic
sea ice response to atmospheric forcings with varying
levels of anthropogenic warming and climate
variability».
Those projections are detailed in Zhang et al, 2010 «Arctic
sea ice response to atmospheric forcings with varying
levels of anthropogenic warming and climate
variability.»
The differences between the quadratic acceleration numbers come from differences in the decadal to multidecadal
variability in the curves which I don't consider very robust (we have shown in Rahmstorf et al. 2012 how strongly these can be affected by a small amount
of «noise» in the
sea -
level data).
Nevertheless such
variability induced by winds or currents may give a false impression
of global
sea level fluctuations in analyses
of tide gauge data.
It uses the satellite data
of sea level to determine the typical
variability patterns
of the
sea surface and thus to establish the link between the locally measured tide gauge values and the global
sea level.
There are many patterns
of behaviour particularly in the Pacific, associated with El Nino
variability — possibly related to Vanuatu's lack
of actual
sea level rise over the last 40 years.
Variability in the prevailing winds (which can extend over decades, England et al. 2014) will therefore lead to variability in the water level along the coasts — but of course we know that the wind can not change global sea level at all as it merely redistributes
Variability in the prevailing winds (which can extend over decades, England et al. 2014) will therefore lead to
variability in the water level along the coasts — but of course we know that the wind can not change global sea level at all as it merely redistributes
variability in the water
level along the coasts — but
of course we know that the wind can not change global
sea level at all as it merely redistributes the water.
The same is true for one source
of sea -
level rise, Greenland melting measured by GRACE: GRACE is a new instrument demanding calibration and Greenland a region known for its marked pluridecadal
variability.
That approach, from Katrina forward, was bound to fail, given the
variability of conditions year to year and persistent (and non-manufactured) uncertainty surrounding some
of the most consequential impacts (for instance, the pace and extent
of warming and
sea -
level rise in this century).
WMO will issue its full Statement on the State
of the Climate in 2017 in March which will provide a comprehensive overview
of temperature
variability and trends, high - impact events, and long - term indicators
of climate change such as increasing carbon dioxide concentrations, Arctic and Antarctic
sea ice,
sea level rise and ocean acidification.
Spatial
variability of the rates
of sea level rise is mostly due to non-uniform changes in temperature and salinity and related to changes in the ocean circulation.
Quadrelli and Wallace (2004) found that many patterns
of NH interannual
variability can be reconstructed as linear combinations
of the first two Empirical Orthogonal Functions (EOFs)
of sea level pressure (approximately the NAM and the PNA).
Much
of what is
of concern to the military is extreme weather events (e.g. Pakistan floods) driven by natural climate
variability and random weather roulette (concerns about
sea level rise and the opening
of the Arctic Ocean are linked more closely to AGW)
The overarching goal
of this WCRP research effort, led by WCRP's Core Project «Climate and Ocean
Variability, Predictability and Change» (CLIVAR) as a Research Focus, is to establish a quantitative understanding of the natural and anthropogenic mechanisms of regional to local sea level variability; to promote advances in observing systems required for an integrated sea level monitoring; and to foster the development of sea level predictions and projections that are of increasing benefit for coastal zone
Variability, Predictability and Change» (CLIVAR) as a Research Focus, is to establish a quantitative understanding
of the natural and anthropogenic mechanisms
of regional to local
sea level variability; to promote advances in observing systems required for an integrated sea level monitoring; and to foster the development of sea level predictions and projections that are of increasing benefit for coastal zone
variability; to promote advances in observing systems required for an integrated
sea level monitoring; and to foster the development
of sea level predictions and projections that are
of increasing benefit for coastal zone management.
In order to use tidal gauges to reliably estimate global
sea level changes, researchers have to successfully separate the components
of shifting land heights and local
sea level variability from any global trends.
The evolution
of El Niño - Southern Oscillation (ENSO)
variability can be characterized by various ocean - atmosphere feedbacks, for example, the influence
of ENSO related
sea surface temperature (SST)
variability on the low -
level wind and surface heat fluxes in the equatorial tropical Pacific, which in turn affects the evolution
of the SST.
Its estimated ice volume and contribution to mean global
sea level reside well within their ranges
of natural
variability, and from the current looks
of things, they are not likely to depart from those ranges any time soon.
Its six chapters cover temperature assessment, precipitation assessment, large - scale climate
variability modes and related oscillation indices, extreme events, climate and composition
of the atmosphere and cryosphere and
sea level.
variability of sea level pressure over the Pacific etc..
The combination
of predicted astronomical tides with projected weather forcing, El Niño related
variability, and secular SLR, gives a series
of hourly
sea level projections for 2005 — 2100.
The study demonstrates that observation - based interpretations, highlighting the role
of winds in past regional
sea level variability, are not inconsistent with the dominance
of AMOC - associated changes in the 21st century.
J. T. Fasullo, R. S. Nerem & B. Hamlington Scientific Reports 6, Article number: 31245 (2016) doi: 10.1038 / srep31245 Download Citation Climate and Earth system modellingProjection and prediction Received: 13 April 2016 Accepted: 15 July 2016 Published online: 10 August 2016 Erratum: 10 November 2016 Updated online 10 November 2016 Abstract Global mean
sea level rise estimated from satellite altimetry provides a strong constraint on climate
variability and change and is expected to accelerate as the rates
of both ocean warming and cryospheric mass loss increase over time.
At the core
of the issue is the fact that, as far as we know, CO ₂
levels are currently very unusual for the Late Pleistocene, about twice the average, while temperatures,
sea levels, and ice are within Holocene
variability range.
A: «Internal
variability versus anthropogenic forcing on
sea level and its components» B: «The rate
of sea -
level rise» C: «Quantifying anthropogenic and natural contributions to thermosteric
sea level rise» D: «Detection and attribution
of global mean thermosteric
sea level change» E: «Long - term
sea level trends: Natural or anthropogenic?»
Abstract: «Global mean
sea level rise estimated from satellite altimetry provides a strong constraint on climate
variability and change and is expected to accelerate as the rates
of both ocean warming and cryospheric mass loss increase over time.
Extending the
sea level record back over the entire century suggests that the high
variability in the rates
of sea level change observed over the past 20 years were not particularly unusual.
Regionally, climate models underestimate the amount
of sea level rise that occured, but do show reasonable agreement for interannual and multidecadal
variability.
People are already experiencing the impacts
of climate change through slow onset changes, for example
sea level rise and greater
variability in the seasonality
of rainfall, and through extreme weather events, particularly extremes
of heat, rainfall and coastal storm surges.
''... when correcting for interannual
variability, the past decade's slowdown
of the global mean
sea level disappears, leading to a similar rate
of sea -
level rise (
of 3.3 ± 0.4 mm yr − 1) during the first and second decade
of the altimetry era.
Here we present an analysis based on
sea -
level data from the altimetry record
of the past ~ 20 years that separates interannual natural
variability in
sea level from the longer - term change probably related to anthropogenic global warming.
Obviously you are not aware that the decadal
variability of ENSO is not in synch with the PDO: The graph is from this post: http://bobtisdale.wordpress.com/2011/06/30/yet-even-more-discussions-about-the-pacific-decadal-oscillation-pdo/ The reasons for the differences are
of course due to the influence
of sea level pressure on the PDO.
«Here we present an analysis based on
sea -
level data from the altimetry record
of the past ~ 20 years that separates interannual natural
variability in
sea level from the longer - term change probably related to anthropogenic global warming... Our results confirm the need for quantifying and further removing from the climate records the short - term natural climate
variability if one wants to extract the global warming signal.»
Specifically, smoothing
sea -
level data (adjusting for natural
variability of ENSO) over the past century fits most closely with a 4th degree polynomial model, and there has very likely not been any slowing in the longer - term background rate
of sea level rise over the period
of the tropospheric «pause».