Sentences with phrase «observed nao»

For this calculation, we scale the observed interannual SLP, SAT and P regression values by the factor 1.53 appropriate for a 30 - year trend and an observed NAO autocorrelation of 0.17 based on detrended data during 1920 — 2012 (Fig.

Given that the model's low - frequency NAO variability is almost entirely internally - generated, and if the same is true for observations, then the chronologies of the simulated and observed NAO time series need not match.

This approach provides a hybrid assessment of the combined influence of anthropogenic climate change [determined from the ensemble - mean of the CESM - LE or from the multi-model Coupled Model Intercomparison Project phase 5 (CMIP5) archive (Taylor et al. 2012)-RSB- and observed NAO variability on climate over the coming decades.

As a corollary, the observed NAO characteristics may also be subject to some uncertainty, and thus any individual simulation need not match observations exactly.

In this way, we can obtain the expected range of projected climate trends using the interannual statistics of the observed NAO record in combination with the model's radiatively - forced response (given by the ensemble - mean of the 40 simulations).

Not exact matches

The westerlies in the Northern Hemisphere, which increased from the 1960s to the 1990s but which have since returned to about normal as part of NAO and NAM changes, alter the flow from oceans to continents and are a major cause of the observed changes in winter storm tracks and related patterns of precipitation and temperature anomalies, especially over Europe.

Variability in the tracks on a year by year basis, for instance, as diagnosed by the models NAO index resembles that observed, explaining about the same amount of variability as observed.

The global climate models (GCMs) are for all intents and purposes able to simulate observed natural variations such as the North Atlantic Oscillation (NAO) and Atlantic Meridional Overturning Circulation (AMOC).

Look, I do not claim that climate models are perfect — far from it — but their matches to observed data at the large scale are impressive — Pinatubo, last 30 years, response to ENSO, NAO response, sea ice response, ozone hole response etc..

Variability in the marine carbon cycle has been observed in response to physical changes associated with the dominant modes of climate variability such as El Niño events and the PDO (Feely et al., 1999; Takahashi et al., 2006), and the NAO (Bates et al., 2002; Johnson and Gruber, 2007).

Statistical studies have debated the correlation between retreating Arctic ice and the negative NAO because it generates a confounding short term warming trend that is contradicted by the longer cooling trend suggested for the LIA as well as observed during the 1960s and 70s.

They constructed a numerical network model from 4 observed ocean and climate indices — ENSO, PDO, the North Atlantic Oscillation (NAO) and the Pacific Northwest Anomaly (PNA)-- thus capturing most of the major modes of climate variability in the period 1900 — 2000.

Thus, winter and spring atmospheric anomalies associated with the positive phase of the NAO may underlie the reduction of summer sea ice extent observed during the 1980s and 1990s.

Indeed, the NAO shows a wide variety of temporal sequences across the 30 members of the CESM - LE, with ensemble member 5 lining up with the observed record just by chance (Fig. 5).

The observed P regression values in areas most strongly affected by the NAO, which includes all of western and Eastern Europe and most of eastern North America, lie within the spread of the 40 values simulated across the CESM - LE (Fig. 3e).

We find that the expected 95 % range of future climate trends induced by NAO fluctuations estimated from the observed statistics of the NAO and the modeled response to increased GHGs is largely similar to that obtained from the CESM - LE directly, attesting to the fidelity of the model's representation of the NAO and the utility of this approach.

If they can be inferred to a reasonable degree, then one can use the observed characteristics of interannual NAO variability to estimate the error on future NAO trends, rather than relying solely on the model.

The observed influence of the NAO on extreme precipitation is largest in eastern North America, with the likelihood of a negative phase extreme rainfall event decreased in the north and increased in the south under the positive phase of the NAO.

Increased negative NAO is observed through solar minima, and negative NAO is directly associated with slower trade winds and hence increased El Nino.

We also find that observed fluctuations in extreme events in Padova are linked to the North Atlantic Oscillation: increases in the NAO Index are on average associated with an intensification of daily extreme rainfall events.

Here we show that the unexplained strengthening of the NAO can be fully simulated in a climate model by imposing observed trends in the lower stratosphere.