wiki:udg/ecoms/RPackage/examples/continentalSelection

Regional-Continental domain selections

In this example we will load data for Europe for the variable surface (2m) minimum temperature (var = tasmin), for the first two members (members = 1:2) of the CFSv2 hindcast (dataset = CFSv2_seasonal_16), considering the wintertime (DJF, season = c(12,1,2)) for the 10-year period 1991-2000 (years = 1991:2000), according to the forecast issued in September (leadMonth = 3). The original variable is 6-hourly . We will retrieve the daily minimum values, by setting the argument time = "DD" and the daily aggregation function to minimum (aggr.d = "min"):

ex2 <- loadECOMS(dataset = "CFSv2_seasonal",
                 var = "tasmin",
                 members = 1:2,
                 lonLim = c(-15,35),
                 latLim = c(32, 75),
                 season = c(12,1,2),
                 years = 1991:2000,
                 leadMonth = 3,
                 time = "DD",
                 aggr.d = "min")

## [2016-05-13 13:26:29] Defining homogeneization parameters for variable "tasmin"
## [2016-05-13 13:26:29] Opening dataset...
## [2016-05-13 13:26:29] The dataset was successfuly opened
## [2016-05-13 13:26:29] Defining geo-location parameters
## [2016-05-13 13:26:30] Defining initialization time parameters
## NOTE: Daily aggregation will be computed from 6-hourly data
## [2016-05-13 13:26:32] Retrieving data subset ...
## [2016-05-13 13:31:41] Done

The size of the object is 35 Mb:

print(object.size(ex2), units = "Mb")
## 35.1 Mb

In this case, the data are stored in a 4D-array, with the dimensions indicated by the dimensionsattribute, always following the canonical ordering of dimensions:

str(ex2$Data)
## num [1:2, 1:903, 1:47, 1:54] 21.6 16.1 21.1 17.4 21.5 ...
##  - attr(*, "dimensions")= chr [1:4] "member" "time" "lat" "lon"

The attribute dimensions provides important information for data collocation in subsequent manipulations of the loaded grid.

Members can be plotted individually by setting multi.member = TRUE in the plotMeanGrid function of the downscaleR package:

plotMeanGrid(ex2, multi.member = TRUE)

Last modified 5 years ago Last modified on May 13, 2016 1:39:15 PM

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