s2dverification: EOF – R documentation

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EOF

Area-Weighted Empirical Orthogonal Function Analysis Using SVD

Description

Performs an area-weighted EOF analysis using SVD based on a covariance matrix by default, based on the correlation matrix if corr argument is set to TRUE.

Usage

EOF(ano, lon, lat, neofs = 15, corr = FALSE)

Arguments

`ano`	Array of anomalies with dimensions (number of timesteps, number of latitudes, number of longitudes). NAs could exist but it should be consistent along time_dim. That is, if one grid point has NAs, all the time steps at this point should be NAs.
`lon`	Vector of longitudes of `ano`.
`lat`	Vector of latitudes of `ano`.
`neofs`	Number of modes to be kept. Default = 15.
`corr`	Whether to base on a correlation matrix (`TRUE`) or on a covariance matrix (default, `FALSE`).

Value

`EOFs`	An array of EOF patterns normalized to 1 (unitless) with dimensions (number of modes, number of latitudes, number of longitues). Multiplying `EOFs` by `PCs` gives the original reconstructed field.
`PCs`	An array of pincipal components with the units of the original field to the power of 2, with dimensions (number of time steps, number of modes). `PCs` contains already the percentage of explained variance so, to reconstruct the original field it's only needed to multiply `EOFs` by `PCs`.
`var`	Percentage ( mode (number of modes).
`mask`	Mask with dimensions (number of latitudes, number of longitudes).
`wght`	Weights with dimensions (number of latitudes, number of longitudes).

Author(s)

History:
0.1 - 2012-10 (F. Lienert, fabian.lienert@ic3.cat) - Original code, inspired by R. Benestad's EOF() in R package clim.pact.
0.2 - 2014-03 (Lauriane Batte, lauriane.batte@ic3.cat) - Bug-fixes:
1- Reversion of latitudes in the weights
2- Correlation matrix was used instead of covariance
3- Double use of the weights
0.3 - 2014-03 (Virginie Guemas, virginie.guemas@bsc.es) - Bug-fixes:
1- Weight computation - division by sum of cos(lat)
2- Shuffling of EOFs in EOF.2 intermediate vector
3- Crash when neofs = 1 sorted out
4- Crash when neofs > nt sorted out
0.4 - 2014-03 (Lauriane Batte, lauriane.batte@ic3.cat) - Fixes:
1- BIG cleanup of code and clarification
2- Reduction of the number of transpositions and associated bug-fixes
4- Remove of the obsolete LINPACK options
0.5 - 2014-04 (Virginie Guemas, virginie.guemas@bsc.es) - Fixes:
1- Bug-fix in dimensions handling EOF composition restitutes now the original field in all cases
2- Simplification of the convention transpose
3- Options to use the correlation matrix rather than the covariance matrix
4- Security checks
5- New normalization of PCs so that PC*EOF only reconstruct the original file
6- Weights = sqrt(cos(lat)) for ano so that covariance matrice weighted by cos(lat)
7- Division of EOF by weights so that the reconstruction is simply EOF * PC
1.0 - 2016-03 (N. Manubens, nicolau.manubens@bsc.es) - Formatting to R CRAN

Examples

# See examples on Load() to understand the first lines in this example
 ## Not run: 
data_path <- system.file('sample_data', package = 's2dverification')
expA <- list(name = 'experiment', path = file.path(data_path, 
            'model/$EXP_NAME$/$STORE_FREQ$_mean/$VAR_NAME$_3hourly',
            '$VAR_NAME$_$START_DATE$.nc'))
obsX <- list(name = 'observation', path = file.path(data_path, 
            '$OBS_NAME$/$STORE_FREQ$_mean/$VAR_NAME$',
            '$VAR_NAME$_$YEAR$$MONTH$.nc'))

# Now we are ready to use Load().
startDates <- c('19851101', '19901101', '19951101', '20001101', '20051101')
sampleData <- Load('tos', list(expA), list(obsX), startDates,
                  leadtimemin = 1, leadtimemax = 4, output = 'lonlat',
                  latmin = 27, latmax = 48, lonmin = -12, lonmax = 40)
 
## End(Not run)
 
# This example computes the EOFs along forecast horizons and plots the one that 
# explains the greatest amount of variability. The example data is very low 
# resolution so it does not make a lot of sense.
ano <- Ano_CrossValid(sampleData$mod, sampleData$obs)
eof <- EOF(Mean1Dim(ano$ano_exp, 2)[1, , 1, , ], sampleData$lon, sampleData$lat)
PlotEquiMap(eof$EOFs[1, , ], sampleData$lon, sampleData$lat)

s2dverification

Set of Common Tools for Forecast Verification

v2.10.0

Apache License 2.0

Authors

BSC-CNS [aut, cph], Virginie Guemas [aut], Nicolau Manubens [aut], An-Chi Ho [ctb, cre], Nuria Perez-Zanon [ctb], Javier Garcia-Serrano [aut], Neven Fuckar [aut], Louis-Philippe Caron [aut], Omar Bellprat [aut], Luis Rodrigues [aut], Veronica Torralba [aut], Alasdair Hunter [aut], Chloe Prodhomme [aut], Martin Menegoz [aut], Domingo Manubens [ctb], Constantin Ardilouze [ctb], Lauriane Batte [ctb], Fabian Lienert [ctb], Julia Giner [ctb], Jean-Philippe Baudouin [ctb], Nube Gonzalez [ctb], Ludovic Auger [ctb], Nicola Cortesi [ctb], Eleftheria Exarchou [ctb], Ruben Cruz [ctb], Isabel Andreu-Burillo [ctb], Ramiro Saurral [ctb]

Initial release

EOF