A Significance Test for Principal Components Applied to a Cyclone Climatology

Overland, James E.; Preisendorfer, Rudolph W.

doi:10.1175/1520-0493(1982)110<0001:astfpc>2.0.co;2

Cited by 420 publications

(196 citation statements)

References 0 publications

Supporting

Mentioning

188

Contrasting

Unclassified

Order By: Relevance

“…A subjective stage of this objective method is the decision for the number, m, of the retained factors. Many criteria have been proposed (Jolliffe, 1986;Overland and Preisendorfer, 1982;Rogers, 1990) but as some are stringent and some others are loose (Thurston and Spengler, 1985), they hardly indicate the same number of factors. In this respect, Jolliffe (1993) states "...different objectives for an analysis may lead to different rule being appropriate".…”

Section: Methodssupporting

confidence: 86%

“…Apart from the selection of the optimum number of factors, another outstanding by-product of this methodology was the assessment of the various criteria. It was revealed that our results were very close to the ones given by MCT (Overland and Preisendorfer, 1982), which we eventually applied in this work. This criterion is designed to determine whether the factors' eigenvalues for a geophysical data set can be distinguished from those drawn at random.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

On the relation between sea surface and lower temperature over the northern hemisphere

2013

Global NEST Journal

View full text Add to dashboard Cite

In this work the covariability of sea surface and lower troposphere temperatures (SST-AT) is investigated for winter (DJFM) and summer (JJAS), over the whole northern hemisphere, by utilizing monthly anomalies in grid boxes for a 22-year period. Air temperature variations in the lower troposphere are examined in terms of 1000-500 hPa thickness. At first, factor analysis (FA) is applied on both sets of data in order to reduce their dimensionality and to group objectively grid points with a similar long term temperature variability. Also, FA revealed numerous teleconnections in both fields, most important being those governed by PNA in the Pacific Ocean and NAO in the Atlantic Ocean. Then, by using the FA results as a guide, correlation coefficients between the mean temperature time series of the subareas defined by FA in the two fields are estimated. The highest values, up to r=0.70, were found for subareas located one over/under the other. Finally, by introducing time lags, an attempt of forecasting either SST form AT or AT from SST is made. Although in some cases the coefficients appear increasing, test showed that the increase is not statistically significant. In any case, it appears that, on monthly time scale, it is the AT that controls SST and not the vice versa.

show abstract

Section: Methodssupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

On the relation between sea surface and lower temperature over the northern hemisphere

2013

Global NEST Journal

View full text Add to dashboard Cite

show abstract

“…The values of each factor are called factor scores and they are usually presented in standardized form, having zero mean and unit variance (Jolliffe, 1986;Manly, 1986). The number m of the retained factors has to be decided, by using various rules (Overland and Preisendorfer, 1982;Jolliffe, 1986) and considering the physical interpretation of the results . A widely used process is the rotation of axes, which creates new factors with different variances, but it keeps the cumulative variance of the m factors unaffected.…”

Section: Methodsmentioning

confidence: 99%

Spatial and temporal 850 hPa air temperature and sea‐surface temperature covariances in the Mediterranean region and their connection to atmospheric circulation

Lolis

Bartzokas

Katsoulis

2002

Intl Journal of Climatology

View full text Add to dashboard Cite

The spatial and temporal covariability between the lower troposphere and sea surface temperatures (SSTs) are studied in the Mediterranean basin for the period 1958-98. Monthly air temperature anomalies for the 850 hPa pressure level (T-850hPa) at 2.5°× 2.5°grid points and SST anomalies in 5°× 5°grid boxes are utilized. As a first step, factor analysis is applied on both sets of data in order to reduce their dimensionality. Then, canonical correlation analysis is applied and this leads to one statistically significant pair of canonical variates for winter and to two pairs for summer. In winter, a teleconnection (see-saw) between western Europe and the eastern Mediterranean at the 850 hPa level is revealed, and a corresponding weaker one between the areas of central-west and eastern Mediterranean for SST. The correlation between T-850hPa and SST appears higher over the eastern Mediterranean. In summer, the first pair of canonical variates reveals a covariability between T-850hPa and SST in the western Mediterranean, and the second one shows a covariability in the eastern Mediterranean, without the existence of any strong spatial teleconnection. The analysis is repeated, using time lags of 1 month, or longer, in order to detect any possible non-synchronous relation. Statistically significant results are found only when T-850hPa leads SST with a time lag of 1 month. In particular, the results are statistically significant for winter only, and the findings are similar to those of the first analysis. Therefore, the existence of a 1 month time scale SST persistence is detected for winter months.

show abstract

“…The question is whether the second mode, representing only 5% of the variability, is significant or not. A Monte-Carlo simulation analysis [Overland and Preisendorfer, 1982] was applied by running i00 simulations of the CEOF analysis on Gaussian random numbers with a standard deviation of 5. None of the resulting random modes explain >6% (Figure 6).…”

Section: Resultsmentioning

confidence: 99%

Complex empirical orthogonal functions analysis of ERS‐1 and TOPEX/POSEIDON combined altimetric data in the region of the Algerian current

Bouzinac¹,

Vázquez²,

Font³

1998

J. Geophys. Res.

View full text Add to dashboard Cite

-15øE and 35ø-40øN) was found to be dominated by the first two CEOFs. These first two modes explain nearly 85% of the variability, with 80% of the total variance for the first one and 5% of the total variance for the second one. The temporal phase of the first mode indicates that a constant frequency of one cycle per year is clearly dominant, corresponding to the seasonal signal. The strongest amplitude is obtained in the southern part of the channel of Sardinia and south of the Strait of Sicily. The temporal amplitude and the temporal phase of the second mode show a periodicity of about 6 months which appears to be associated with the variability of the Algerian current as the phase isolines are parallel to the mean current path along the Algerian coast. The strongest amplitude of the second mode is located near the African coast at ---4øE and 8øE. These two points of high variability could correspond to eddy detachments from the main current.

show abstract

A Significance Test for Principal Components Applied to a Cyclone Climatology

Cited by 420 publications

References 0 publications

On the relation between sea surface and lower temperature over the northern hemisphere

On the relation between sea surface and lower temperature over the northern hemisphere

Spatial and temporal 850 hPa air temperature and sea‐surface temperature covariances in the Mediterranean region and their connection to atmospheric circulation

Complex empirical orthogonal functions analysis of ERS‐1 and TOPEX/POSEIDON combined altimetric data in the region of the Algerian current

Contact Info

Product

Resources

About