Sentences with phrase «scale variability over»

The mean state of ENSO, its global patterns of influence, amplitude of interannual variability, and frequency of extreme events show considerable multidecadal and century - scale variability over the past several centuries.»

Not exact matches

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.

While this leads to an elevation in the level of scientific understanding from very low in the TAR to low in this assessment, uncertainties remain large because of the lack of direct observations and incomplete understanding of solar variability mechanisms over long time scales.»

We're also learning that natural variability is really important when we're looking over time scales of anywhere from the next year or two to even a couple of decades in the future.

Koffman, B.G., Kreutz, K.J., Breton, D.J., Kane, E.J., Winski, D.A., Birkel, S.D., Kurbatov, A.V., and Handley, M.J., 2014, Centennial - scale variability of the Southern Hemisphere westerly wind belt in the eastern Pacific over the past two millennia.

Seasonal to centennial - scale variability of microparticle concentration and size distribution in the WAIS Divide ice core over the past 2.4 ka.

Aims: We aim to demonstrate the persistence of the phenomenon over time scales of a few years and to search for variability of our previously detected excesses.

Forecasts can only be tested against future temperatures over time scales sufficiently long to be largely outside the range of shorter term variability.

For variability on a long time scale, the effect is generally constant over a short time period (such as Milankovitch cycles).

For instance, an influential analysis by Hawking & Sutton (2009)(link to figures) has suggested that internal climate variability account for only about 20 % of the variance over the British isles on a 50 - year time scale.

They have not analyzed the first year of data yet, but in my lab we have looked at results from a similar set of moorings at 15N (Uwe Send's work) and find rather significant variability on weekly to monthly time scales (but no trend over the 4 years of data).

There are other and very separate issues you've raised (in minimal detail) regarding models, but quite frankly GCMs are not and never were intended to project decadal scale variability — and over the scales that those climate models cover there's certainly no «hiatus».

However, atmospheric CO2 content plays an important internal feedback role.Orbital - scale variability in CO2 concentrations over the last several hundred thousand years covaries (Figure 5.3) with variability in proxy records including reconstructions of global ice volume (Lisiecki and Raymo, 2005), climatic conditions in central Asia (Prokopenko et al., 2006), tropical (Herbert et al., 2010) and Southern Ocean SST (Pahnke et al., 2003; Lang and Wolff, 2011), Antarctic temperature (Parrenin et al., 2013), deep - ocean temperature (Elder eld et al., 2010), biogeochemical conditions in the Northet al., 2008).

Each subsystem, moreover, has its own internal variability, all other things being constant, over a fairly broad range of time scales.

It is quite clear that the perturbation that we are currently imposing is already large, and will be substantially larger, by up to an order of magnitude, than any plausible natural variability over this time scale.

The ability of a sampling method to accurately measure seasonal variability does not indicate that the method is valid for estimating trends over centennial time scales.

However, in the paper the authors actually stated that «our conclusion about the dominance of the CRF over climate variability is valid only on multimillion - year time scales».

This in turn can have had a number of possible causes: «natural» tropical variability — for instance, the winter (DJF) tropical Pacific cooled over these two years, possibly as part of larger - scale ENSO variability.

While this leads to an elevation in the level of scientific understanding from very low in the TAR to low in this assessment, uncertainties remain large because of the lack of direct observations and incomplete understanding of solar variability mechanisms over long time scales.»

If you are of the opinion that temperature variability on a short time scale is insignificant, how can we declare as fact that the rise in global temperature over the past 50 years is incontrovertibly tied to the increase in CO2 levels?

«Aerosol variability, synoptic - scale processes, and their link to the cloud microphysics over the northeast Pacific during MAGIC.»

Attribution of the observed warming to anthropogenic forcing is easier at larger scales because averaging over larger regions reduces the natural variability more, making it easier to distinguish between changes expected from different external forcings, or between external forcing and climate variability.

Long - term climate variability is the range of temperatures and weather patterns experienced by the Earth over a scale of thousands of years.

The stagnation in greenhouse warming observed over the past 15 + years demonstrates that CO2 is not a control knob that can fine tune climate variability on decadal and multi-decadal time scales.

The U.S. military seems interested in climate variations / change on timescales from seasonal to scales out to about 30 years, a period over which natural climate variability could very well swamp anthropogenically forced climate change.

The scale of the solar induced natural variability that has been observed over more than 500 years swamps any warming effect from human CO2.

However, models would need to underestimate variability by factors of over two in their standard deviation to nullify detection of greenhouse gases in near - surface temperature data (Tett et al., 2002), which appears unlikely given the quality of agreement between models and observations at global and continental scales (Figures 9.7 and 9.8) and agreement with inferences on temperature variability from NH temperature reconstructions of the last millennium.

Models all produce natural variability, many of which show temperature flatlines over decadal timescales, and given the wide importance of natural variability over < 10 year time scales and uncertain forcings, one can absolutely not claim that this is inconsistent with current thinking about climate.

Most of the variability in this gravitational pull occurs over time scales of less than a year.

«Our analysis shows warming underway by 1800, large variations up and down throughout the 19th century, and that variability on the 3 - 15 year scale has been dramatically decreasing over the past two centuries.»

e.g. Y. Markonis, and D. Koutsoyiannis, Climatic variability over time scales spanning nine orders of magnitude: Connecting Milankovitch cycles with Hurst — Kolmogorov dynamics, Surveys in Geophysics, 34 (2), 181 — 207, doi: 10.1007 / s10712 -012-9208-9, 2013.

Ole Willy says, «The hiatus in warming observed over the past 16 years demonstrates that CO2 is not a control knob on climate variability on decadal time scales.»

We believe this is the first attempt to estimate the influence of mechanical thinning on runoff over multi-year broad - scale restoration projects that accounts for the effects of climate variability.

(A) coordinate programs at the National Oceanic and Atmospheric Administration to ensure the timely production and distribution of data and information on global, national, regional, and local climate variability and change over all time scales relevant for planning and response, including intraseasonal, interannual, decadal, and multidecadal time periods;

BartH notes that «At relatively short time scales (say, a couple of decades), natural variability will dominate over systematic climate change, and there is more added value to expect from ensuring that the projections reflect natural variability adequately than to assess the degree to which the background climate changes.»

In the context of large - scale variability in the North Atlantic and North Pacific oceans, the spring 2010 Atlantic Multi-decadal Oscillation (AMO; area averaged SST over the North Atlantic) was the highest since 1948 (http://www.esrl.noaa.gov/psd/data/correlation/amon.us.data) while the spring 2010 PDO (http://jisao.washington.edu/pdo/) was near neutral.

Here is their description of the work: The influence of solar variability on Earth's climate over centennial to millennial time scales is the subject of considerable debate.

Moreover, we suggest that accounting for any spatial or seasonal biases in the stack would tend to reduce its variability because of the cancellation of noise in a large - scale mean and the opposing nature of seasonal insolation forcing over the Holocene, causing the Holocene temperature distribution to contract.

Furthermore, we characterize this variability over the widest possible range of scales that the available information allows, and we try to connect the deterministic Milankovitch cycles with the Hurst — Kolmogorov (HK) stochastic dynamics.

It doesn't mean that there can't be any natural variability that appears as wobbles in the temperature record (or in other climate variables), masking the multi-decadal temperature trend over a time scale shorter than 20 years with the effect that the longer term trend is not statistically detectable in the time series, if one chooses the time period only short enough.

The North Atlantic Oscillation (NAO), the dominant mode of atmospheric circulation variability over the North Atlantic / European sector, is a leading governor of wintertime climate fluctuations in Europe, the Mediterranean, parts of the Middle East and eastern North America over a wide range of time scales from intra-seasonal to multi-decadal (e.g., Hurrell 1995; Hurrell et al. 2003).

Jan Perlwitz says:» It doesn't mean that there can't be any natural variability that appears as wobbles in the temperature record (or in other climate variables), masking the multi-decadal temperature trend over a time scale shorter than 20 years with the effect that the longer term trend is not statistically detectable in the time series, if one chooses the time period only short enough.»

«We use geochemical data from a sediment core in the shallow - silled and intermittently dysoxic Kau Bay in Halmahera (Indonesia, lat 1 ° N, long 127.5 ° E) to reconstruct century - scale climate variability within the Western Pacific Warm Pool over the past ~ 3500 yr.

Analyses of tide gauge and altimetry data by Vinogradov and Ponte (2011), which indicated the presence of considerably small spatial scale variability in annual mean sea level over many coastal regions, are an important factor for understanding the uncertainties in regional sea - level simulations and projections at sub-decadal time scales in coarse - resolution climate models that are also discussed in Chapter 13.

If a frequency of sites spatially and of data collection over time can produce enough dynamically significant data points to satisfy the requirements of Chaos (eg, antialiasing, bifurcation), then we can know just how badly we are measuring the climate, and whether some currently ontic variability is really aleatory, or may be semi-deterministic in some spans and scales if only we have enough granularity in our sampling.

Proxy - based reconstructions of past climate provide insights into externally forced and intrinsic variability over regional to global scales and can be used to place recent trends in a long - term context.

However, changes in climate at the global scale observed over the past 50 years are far larger than can be accounted for by natural variability.

We find that the reported discrepancy can be traced to two main issues: (1) unforced internal climate variability strongly affects local wetness and dryness trends and can obscure underlying agreement with WWDD, and (2) dry land regions are not constrained to become drier by enhanced moisture divergence since evaporation can not exceed precipitation over multiannual time scales.

It seems that every new climate scenario making the media over the past 20 years they always describe a warm future on a multidecadal scale ignoring a cool future as if variability didn't exist, but isn't scientific climatology primarily concerned with longer millenia time scales of a thousand years or more?

When subgrid scale variability is inferred from the AGCM meteorology, dust emission shows significant improvement especially over the Sahara and Asia.