TITLE

Non-Gaussianity and Asymmetry of the Winter Monthly Precipitation Estimation from the NAO

AUTHOR(S)
Pires, Carlos A.; Perdigão, Rui A. P.
PUB. DATE
February 2007
SOURCE
Monthly Weather Review;Feb2007, Vol. 135 Issue 2, p430
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The present work assesses non-Gaussianity and asymmetry within the statistical response of the monthly winter (December–February) precipitation to the North Atlantic Oscillation (NAO) over the North Atlantic–European region (NAE). To evaluate asymmetry, data are split through the median of the NAO index and side correlations are computed for each regime [negative and positive phases of the NAO (NAO- and NAO+, respectively)]. The following statistically significant differences between these correlations are found: (a) near the central North Atlantic, around 40°N, 20°W, and southeast of Iceland, with much stronger correlations in the wet-favorable regime: NAO- in the first location and NAO+ in the second location; (b) around 42°N, 48°W in the west North Atlantic; and (c) south of Greenland and in the west Mediterranean near 36°N, where, in both cases, the correlation is only relevant for the dry-favorable NAO+ regime. Based on the above decomposition, a map of a statistical test of asymmetry, applicable for every bivariate distribution, is shown. To evaluate redundancy and non-Gaussianity, the mutual information (MI) is computed from information theory. Its positive contributions resulting from the linear correlation, a purely Gaussian term, and non-Gaussianity, which vanishes in pure Gaussian cases, are studied. The MI is estimated through two methods: 1) the truncated Edgeworth expansion of the bivariate probability density function in terms of Hermite polynomials and cumulants, and 2) the maximum entropy method. This method is quite general, while the first one is only applicable for small deviations from Gaussianity. The map of non-Gaussian MI over the NAE domain reveals some coherent regions, where the nonlinear component of the response of monthly winter precipitation to the NAO is more important. The MI is evaluated both for the original pair of variables and for that pair after being subjected to Gaussian anamorphosis in order to prevent the influence of marginal outliers and keep the applicability of the Edgeworth method.
ACCESSION #
23980397

 

Related Articles

  • A Global View of Non-Gaussian SST Variability. Sura, Philip; Sardeshmukh, Prashant D. // Journal of Physical Oceanography;Mar2008, Vol. 38 Issue 3, p639 

    The skewness and kurtosis of daily sea surface temperature (SST) variations are found to be strongly linked at most locations around the globe in a new high-resolution observational dataset, and are analyzed in terms of a simple stochastically forced mixed layer ocean model. The predictions of...

  • Winter Mixed Layer Development in the Central Irminger Sea: The Effect of Strong, Intermittent Wind Events. Våge, Kjetil; Pickart, Robert S.; Moore, G. W. K.; Ribergaard, Mads Hvid // Journal of Physical Oceanography;Mar2008, Vol. 38 Issue 3, p541 

    The impact of the Greenland tip jet on the wintertime mixed layer of the southwest Irminger Sea is investigated using in situ moored profiler data and a variety of atmospheric datasets. The mixed layer was observed to reach 400 m in the spring of 2003 and 300 m in the spring of 2004. Both of...

  • Modeled winter sea ice variability and the North Atlantic Oscillation: a multi-century perspective. Strong, Courtenay; Magnusdottir, Gudrun // Climate Dynamics;Mar2010, Vol. 34 Issue 4, p515 

    The relationship between winter sea ice variability and the North Atlantic Oscillation (NAO) is examined for the time period 1860–2300. This study uses model output to extend recently reported observational results to multi-century time scales. Nine ensemble members are used in two Global...

  • Does Global Warming Affect Sea Temperature?  // USA Today Magazine;Jun2004, Vol. 132 Issue 2709, p12 

    States that a North Atlantic Ocean circulation system was weakened in the late 1990, which could have effects on the climate, according to a study from the U.S. National Aeronautics and Space Administration. Information on North Atlantic Oscillation atmospheric pressure system; Implications of...

  • Anatomy of Synoptic Eddy-NAO Interaction through Eddy Structure Decomposition. Ren, Hong-Li; Jin, Fei-Fei; Gao, Li // Journal of the Atmospheric Sciences;Jul2012, Vol. 69 Issue 7, p2171 

    A method of eddy structure decomposition is proposed to detect how low-frequency flow associated with the North Atlantic Oscillation (NAO) organizes systematically synoptic eddy (SE) activity to generate in-phase and upstream feedbacks. In this method, a statistical eddy streamfunction (SES)...

  • Mechanism of Interdecadal Thermohaline Circulation Variability in a Coupled Ocean–Atmosphere GCM. Dong, Buwen; Sutton, Rowan T. // Journal of Climate;Apr2005, Vol. 18 Issue 8, p1117 

    Interdecadal variability of the Atlantic thermohaline circulation (THC) is studied in the third version of the Hadley Centre global coupled atmosphere–ocean sea-ice general circulation model (HadCM3). A diagnostic approach is used to elucidate the mechanism that governs the variability...

  • North Atlantic decadal regimes in a coupled GCM simulation. Raible, C.C.; Luksch, U.; Fraedrich, K.; Voss, R. // Climate Dynamics;Dec2001, Vol. 18 Issue 3/4, p321 

    The non-stationarity of the North Atlantic atmosphere-ocean coupling is investigated utilizing a long time integration of a coupled atmosphere-ocean general circulation model (GCM) and a consistent atmospheric experiment forced by the climatological sea surface temperature (SST) of the coupled...

  • Particle Flux in the Deep Sargasso Sea. CONTE, MAUREEN H.; WEBER, J. C. // Oceanography;Mar2014, Vol. 27 Issue 1, p142 

    The Oceanic Flux Program (OFP) sediment trap time series, the longest running time series of its kind, has continuously measured particle fluxes in the deep Sargasso Sea since 1978. OFP results provided the first direct observation of seasonality in the deep ocean, and they have documented the...

  • Trends in coastal upwelling intensity during the late 20th century. Narayan, N.; Paul, A.; Mulitza, S.; Schulz, M. // Ocean Science Discussions;2010, Vol. 7 Issue 1, p335 

    This study presents linear trends of coastal upwelling intensity in the later part of the 20th century (1960-2001) employing various indices of upwelling, derived from meridional wind stress and sea surface temperature. The analysis was conducted in the four major coastal upwelling regions in...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics