This is a major release that adds a range of substantial new features and fixes a number of major and minor bugs.
- All functions now accept 3-d arrayed data, enabling the possibility of
using them on gridded climate data. A new data set (
cruts4) has been added to test this new function. - Function
<spei>now accepts non-monthly data (that is, data with frequency other than 12). - A thorough set of test functions have been implemented to help developing new functions without compromising the old results (Thanks to Doug Freedman who wrote the seminal set of tests).
- More thorough data and options checks have been implemented, and a single error / warning message is produced containing all the errors upon failure.
- Different verbosity levels are now implemented in all functions: now they
print information about the options being used. A new argument (
verbosity) can be used to override this behavior if not wanted. - Different versions of the Penman-Monteith ETo calculation have been
implemented in function
<penman>. - A new option to include CO2 concentration data is now available in function
<penman>. - A new option for when no wind data are available in function
<penman>. <plot.spei>has been completely rewritten based onggplot2, solving some bugs and enabling more flexibility.
- Several minor bugs in
<thornthwaite>,<hargreaves>, and<penman>functions have been solved (output difference is less than 0.1%). - A bug in
<spei>has been solved that resulted in bad cumulative data when using a non-rectangular kernel, leading to incorrect SPEI values.
- Allowing for data with frequency other than 12 in
<spei>function.
- Corrected an error in
<spei>function, which was not working when distribution was Gamma or PeasonIII and using user provided parameters. (Thanks to Emanuele Cordano, emanuele.cordano@gmail.com -- 'ecor') - Added probability of monthly precipitation = 0 (pze) when using user provided parameters. (Thanks to Emanuele Cordano).
- Corrected a bug in the \code{\link{kern}} function which resulted in a multiplicative kernel instead of an additive one such the one expected in the \code{\link{spei}} and \code{\link{spi}} functions.
- Plotting methods for \code{spei} objects completely rewritten, now using \code{ggplot2}. Additionally, a bug causing a bad representation of time series starting in months other than January has been corrected.
- Corrected an error in the function \code{\link{thornthwaite}} which resulted in wrong potential evapotranspiration estimates when a multivariate time series was used as input.
- Corrected an error in the function \code{\link{spi}} which resulted in wrong handling of zero precipitation months when using the Gamma or PearsonIII distribution.
- Minor fixes to the \code{\link{spi}} and \code{\link{plot.spei}} functions to correctly handle \code{spei} objects when they result from a call to \code{\link{spi}}.
- Modification to the \code{\link{kern}} function, which now yields kernel coefficients averaging one.
- Corrected an error in the functions \code{\link{spi}} and \code{\link{spei}} which resulted in ub-pwm method being used irrespective of the value of the \code{fit} parameter used, when using the 'Gamma' or 'PearsonIII' distributions.
- Minor changes to the documentation.
- Optimization of function \code{\link{spei}}, now using embed() for accumulating the data at the desired time scale.
- Minor fixes to functions \code{\link{penman}} and \code{\link{pwm}}.
- Documentation of the \code{\link{penman}} function defined by mistake ed as the saturation vapor pressure, while it should read 'actual vapor pressure'.
- Function \code{\link{zzz.R}} added to display basic information about the SPEI package at startup.
- Function \code{\link{SPEINews}} added to display the NEWS file.
- Minor fixes to functions \code{\link{spei}} and \code{\link{penman}}.
- Added new option for user-supplied SPEI parameters in the \code{\link{spei}} function. This overrides the fitting of a probability function to the data.
- Added new dataset \code{\link{cabinda}} from Allen et al. (1998).
- Fixed a bug causing several functions to fail when a time series not belonging to matrix class was provided.
- Function \code{\link{plot.spei}} now distinguishes between calls to \code{\link{spei}} and \code{\link{spi}} and labels the axis accordingly.
- Functions \code{\link{spei}} and \code{\link{spi}} now yield an object of class "spei".
- New functions for summarizing and plotting "spei" objects are provided.
- An option to establish a reference period for the computation of the indices has been implemented in functions \code{\link{spei}} and \code{\link{spi}}.
First release of the SPEI package.