         NAME
              clm - Input data files for LPJmL runs

         DESCRIPTION
              LPJmL is driven by monthly fields of temperature,
              precipitation, cloudiness and number of days with rain.
              Additionally static information on soil properties,
              geographic coordinates of climate and soil data, and mean
              annual atmospheric CO2 concentration are required. Except
              for CO2 all files are binary data including a header (except
              for the soil and lake fraction data).

            Structure of the header
              header name
                   (7 byte char array, LPJCLIM for temp, precip, wet days
                   and cloudiness, LPJGRID for coordinate data, LPJLUSE
                   for land use data, LPJ_COW for country codes, LPJDAMS
                   for reservoir data)

              header version
                   (4 byte integer, currently set to 3, also used to
                   determine if input data needs byte swapping)

              order
                   (4 byte integer, values are either 1 (cellyear) or 2
                   (yearcell))

              firstyear
                   (4 byte integer, first year of data record)

              nyear
                   (4 byte integer, total number of years)

              firstcell
                   (4 byte integer)

              ncell
                   (4 byte integer, number of grid cells represented)

              nbands
                   (4 byte integer)

              cellsize_lon
                   (4 byte float, longitude cellsize in deg)

              scalar
                   (4 byte float conversion factor)

              cellsize_lat
                   (4 byte float, latitude cellsize in deg)

              datatype
                   (4 byte int, 0 for byte, 1 for short, 2 for int, 3 for
                   float, 4 for double)

            Sorting of the climate data
              The sorting of the monthly climate data and of the land use
              data does not correspond to a standard file format but is a
              mixture of BSQ (band sequential) and BIP (band interleaved
              by pixel). You start with 12 monthly values (or with 24 land
              use-fractions) of the first year and first grid cell. After
              that, the first twelve monthly values of the second cell
              follow and so on. Once you are done with all grid cells, you
              continue with the first grid cell's monthly data of the
              second year. This format is called "cellyear" in the LPJmL
              vocabulary and is the only format that is supported from
              LPJmL-version 3.2 and above ("YEARCELL" = BIP has been used
              in previous LPJ-versions).  Once you have a data set that
              you want to apply, you use any programming language, to
              write the header to a file. In C, you can use the function
              fwriteheader(..)  in src/tools/header.c to write headers (or
              freadheader(...) to read it) Datasets can be converted to
              LPJ-format (including headers) from plain binary input files
              (BIP) with the executable cru2clm that has been provided
              with the LPJmL distribution.  Data needs to be stored in the
              same order as the input grid.

            Input data files
              soil data
                   (1 file) data type char (1 byte), the grid needs to be
                   the same as your input grid / climate data
                   values are currently ranging from 0 to 9
                   corresponding soil parameters can be found in
                   par/soil.par
                   no header

              climate data
                   (all monthly values, 4 files + 1 file with atmospheric
                   CO2 concentrations)

                   - temperature [scaled: degree Celsius*10]
                     size of header: 38 bytes

                   - precipitation [mm/month]
                     size of header: 38 bytes

                   - cloudiness [%]
                     for internal computation of radiation
                     size of header: 38 bytes

                   - wet days
                     number of wet days per month (needed only, if your

                   are using the
                     "weather generator", that distributes rain within
                   month randomly)
                     size of header: 38 bytes

                   - atmospheric carbon dioxide [ppmv]
                     global annual mean CO2 concentration as ASCII file
                     format: year concentration
                     Example
                       1990 354.19
                       1991 355.59
                       1992 356.37
                       1993 357.04
                       1994 358.88

              Land use data

                   - land use:
                     in C data type short (2 bytes), grid needs to be the
                   same as your input grid / climate data
                     values range between 0 and 1000 (fraction *1000)
                     each grid cell and year has 24 entries: 12 for rain-
                   fed crops, 12 for irrigated crops
                     crop order is as follows:
                     1: temperate cereals, 2: rice, 3: maize, 4: tropical
                   cereals, 5: pulses,
                     6: temperate roots, 7: tropical roots, 8: oil crops
                   sunflower, 9: oil crops soybean,
                     10: oil crops groundnut, 11: oil crops rapeseed, 12:
                   pasture (C3/C4 mix left to LPJmL to determine)

                   - country codes:
                     in C data type short (2 bytes)
                     for each cell two values: countrycodes (n=197) and
                   regioncodes (n=433)

                   - river routing:
                     in C data type int (4 bytes), the grid needs to be
                   the same as your input grid / climate data
                     for each cell two values: one in which cell to rout
                   the water
                                               one with the distance [km]
                   between the midpoints of the two cells

                     -9: inland sink or outflow to the ocean

         AUTHORS
              Werner von Bloh (Werner.von.Bloh@pik-potsdam.de), Sibyll
              Schaphoff (Sibyll.Schaphoff@pik-potsdam.de), Stefanie Rost
              (Jachner) (Stefanie.Rost@pik-potsdam.de), Marlies
              Gumpenberger (Marlies.Gumpenberger@pik-potsdam.de), Tim
              Beringer (Erbrecht) (Tim.Beringer@pik-potsdam.de), Christoph
              Mueller (Christoph.Mueller@pik-potsdam.de)

         SEE ALSO
              lpjml(1), cru2clm(1), txt2clm(1), catclm(1), grid2clm(1),
              cft2clm(1), printclm(1), printheader(1)