# makeGlobalStat: Compute global statistic of a variable In RCMIP5: Tools for Manipulating and Summarizing CMIP5 Data

## Description

Calculates a global summary for CMIP5 data, usually weighted by the grid cell areas used by each particular model. If no area weighting is supplied, one is computed based on the lon/lat values of `x`. The default statistic is weighted.mean, but any summary function that returns a numeric result can be used.

## Usage

 ```1 2``` ```makeGlobalStat(x, area = NULL, verbose = FALSE, sortData = FALSE, FUN = cmip5.weighted.mean, ...) ```

## Arguments

 `x` A `cmip5data` object `area` An area `cmip5data` object `verbose` logical. Print info as we go? `sortData` logical. Sort `x` and `area` before computing? `FUN` function. Function to apply across grid `...` Other arguments passed on to `FUN`

## Details

The stat function is calculated for all combinations of lon, lat, and Z (if present). This function is more complicated than the other make...Stat functions, because it provides explicit support for area-weighted functions. We expect that weighted.mean and a weighted sum will be the most frequent calculations needed. Note that the base R `weighted.mean` function doesn't work well for CMIP5 data, and so `cmip5.weighted.mean` is used as a default function. Any other user-supplied stat function must follow the weighted.mean syntax, in particular accepting parameters 'x' (data) and 'w' (weights) of equal size, as well as dots(...).

## Value

A `cmip5data` object, in which the `val` dimensions are the same as the caller for Z (if present) and time, but lon and lat are reduced to 1 (i.e. no dimensionality). A `numCells` field is also added, recording the number of cells in the spatial grid.

## Note

If `x` and optional `area` are not in the same order, make sure to specify `sortData=TRUE`.

## See Also

`makeAnnualStat` `makeZStat` `makeMonthlyStat` `cmip5.weighted.mean`

## Examples

 ```1 2 3``` ```d <- cmip5data(1970:1975) # sample data makeGlobalStat(d) summary(makeGlobalStat(d)) ```

### Example output

```CMIP5: var, model experiment,  x  x 0 x 72, 1970 to 1975, from 1 ensemble
CMIP5 data (spatial summary of 21 cells)
Variable: var (unit) from model model
Data range: 1 to 1 Mean: 1
Experiment: experiment - 1 ensemble(s)
Spatial dimensions: lon [] lat [] Z [0]
Time dimension: mon [72] days since 1970-01-01
Size: 0.0 MB
Provenance has 4 entries
```

RCMIP5 documentation built on May 1, 2019, 6:28 p.m.