depudm               package:climatol               R Documentation

_M_o_n_t_h_l_y _d_a_t_a _h_o_m_o_g_e_n_i_z_a_t_i_o_n

_D_e_s_c_r_i_p_t_i_o_n:

     Climatological series homogeneity studies, with missing data
     estimation, inhomogeneities (point errors, mean shifts and trends)
     detection, and graphical displays.

_U_s_a_g_e:

       depudm(varcli, anyi, anyf, nm = 12, wa = 100, dz.max = 2, difumb = 0.05,
         leer = TRUE, a = 0, b = 1, wz=0.001, sqrtrans = FALSE, ttip = 3,
         refglob = FALSE, ndec = 1, pval = 0.05, graf = FALSE, auto = FALSE,
         verb=TRUE)

_A_r_g_u_m_e_n_t_s:

  varcli: Acronym of the name of the studied climatic variable, as in
          the data file name.

    anyi: Initial year of the data present in the file (four digits)

    anyf: Final year of the data present in the file (four digits)

      nm: Number of series in each station. (Default=12, for monthly
          data).

      wa: Shape parameter of the weighting function '1/(1+d^2/wa)',
          where d stands for distance. Low values (1-10) increase the
          weight of nearby stations, while high values (>1000) take in
          account also the far stations influence. Do 'wa=0' if you
          want an unweighted average of all the stations.

  dz.max: Threshold to accept differences between observed and
          estimated data, in standard deviation units. (Only used when
          'auto=TRUE').

  difumb: Maximum acceptable difference in the series average values
          between missing data filling iterations. This process will
          stop when the maximum difference is lower or equal to
          'difumb'.

    leer: if 'TRUE', climatological data will be read from files. (Can
          be set to 'FALSE' if data have already been read in a
          previous call to 'depudm').

    a, b: Parameters of the optional transformation 'a+b*dat' to be
          applied to data when read from the files.

      wz: Scale parameter of the vertical coordinate 'Z'. The default
          value assumes that 'X' and 'Y' are expressed in km, while 'Z'
          is expressed in m.  Can be used to change the 'Z' weight in
          inter-station distance computations.

sqrtrans: if 'TRUE', a square root transformation will  be applied to
          all data greater than 1. (Useful with e.g. precipitation
          data, to approximate their distribution to a Gauss one).

    ttip: Type of standardization:

          _0: none,

          _1: deviations from the mean,

          _2: proportions of the mean (only for means greater than 1),

          _3: full standardization (subtract the mean and divide by the
               standard deviation).

 refglob: if 'TRUE', use annual averages for normalization of all the
          series of each station. Incompatible with 'graf=TRUE'. Can be
          useful in arid places with frequent null precipitation mixed
          with high precipitation values in other years, making quite
          unstable the computation of their averages.

    ndec: Number of decimal places of the purged data, to be saved in
          the file 'VAR_AI-AF.dep'.

    pval: If greater than 0, t-test of mean difference will be applied
          to running windows of 10 and 20 terms (between samples of 5
          and 10 terms), and an overall trend test. If 'graf=TRUE',
          p-values of the t-test will be plotted and, provided that the
          trend is significant (lower than 'pval'), the regression line
          with time will be plotted as well.

    graf: If 'TRUE', interactive graphs will be displayed for each
          series.

    auto: If 'TRUE', data whose differences to their estimated
          (normalized) values are greater than 'dz.max' will be
          substituted by their estimates.

    verb: If 'TRUE', progress indications will be shown in the
          terminal.

_D_e_t_a_i_l_s:

     This is the main function for error correction and homogeneity
     testing of the climatological series, and makes frequent calls to
     other subordinated functions.  The climatological series are read
     from files named 'VAR_AI-AF.dat', and the coordinates and names of
     the stations from 'VAR_AI-AF.est', where 'VAR' stands for any
     acronym of the involved climatological variable, and 'AI' and 'AF'
     are the two last digits of the initial and final year of the data.
     Data are stored station by station, and chronologically within
     each station block.  Missing values are specified as 'NA' (the
     usual way in R). In the stations file there will be a record
     (line) for each station, with structure 'X Y Z ID NAME', where 'X'
     and 'Y' are the UTM coordinates in km, 'Z' the altitude in m, 'ID'
     a station identifier, followed by the full 'NAME' of the station,
     that must be put between double quotes if it contains any space
     character (see the example files in the package's data directory).
      'depudm' will save the purged, filled series in files
     'VAR_AI-AF.dep', eventually overwriting the pre-existing ones.
     (Rename them if results of different calls to 'depudm' are to be
     saved). A log of each run will also be appended in a file named
     'climatol.log'.

_V_a_l_u_e:

     Objects created by this function (original data, 'dat.d';
     normalized data, 'dat.z'; estimated data, 'dat.e'; ...) will
     remain resident in the memory space during the rest of the R
     session while not explicitly removed, therefore been susceptible
     to apply on them all the extended variety of statistical and
     graphic functions available in R.

_N_o_t_e:

     As inhomogeneities in one series will affect other nearby series,
     making them suspects of inhomogeneity even if they are good, it is
     advisable to proceed step by step, beginning with a fairly high
     'wa' (>=1000) to only correct the most prominent errors, and
     successively repeat the process with decreasing values of 'wa'.

_A_u_t_h_o_r(_s):

     Jose A. Guijarro

_R_e_f_e_r_e_n_c_e_s:

     Climatol: Software libre para la depuracin y homogeneizacin de
     datos climatolgicos. IV Congress of the Spanish Climatology
     Society (Santander, 2-5 of November 2004).

_S_e_e _A_l_s_o:

     'grafanom', 'grabeps', 'depstat'

_E_x_a_m_p_l_e_s:

       #The two files PTOT_51-00.* of the package's data directory must be
       #  first copied to the working directory. Then run:
       ## Not run: depudm("PTOT",1951,2000,b=.1,ttip=2,sqrtrans=TRUE,graf=TRUE)

