Explanation notes for PRECIS exported outputs files
These notes describe how the PRECIS output text files are structured to facilitate the use of it by the
users. These are simple notes and not a scientific description of the results.
1. The data files contain the outputs of PRECIS experiments at a resolution of 50x50km. Thus,
every point inside the grid box will be represented by the same value.
2. The files were organized by countries subdirectories (see Table 1 for country list). Each country
subdirectory contain two directories with the PRECIS outputs forced by HadAM3P and
ECHAM4 Global Models. Then for each GCM directory we have the outputs from the two
SRES emission scenarios employed in the experiments (A2 and B2). Finally, each SRES
subdirectory incorporate the variables that are described in Table 2. Figure 1 show the directory
structure of PRECIS data files.
3. The data file name were formed considering the longitude and latitude of the central point of
each grid box. All grid box that are fully or partially within the border of the country were
selected.
4. Each file are in text format, so the user can manage it with excel or other packaged. The files
have three main blocks, having the monthly mean values (columns 1-12 are for months and
column 13 is the annual). The block description is as following:
a) the first block “Model_Current_Climate_raw_values” is for the GCM outputs for 19611989 period and should be used to analyze how the model represent the current climate
conditions, however, care should be take comparing these values with observations at stations
locations. While the stations values represent the climate condition in the point where they are
located, the model values are indicating the mean conditions for the 50x50km grid box . At the
end of this block there is a line (Mean) with the 1961-19891 long term average, which should be
considered as the baseline climatology;
b) the second block “Model_Future_raw_values” contain the values as simulated by the
model for the future climate. Despite these values are useful for some analysis, a more useful
information appears in the next block;
c) the third block “Model_Future_Anomalies_(Climate_Changes)” comprise the differences
of model future climate and model baseline climatology. These are the well knowledge delta or
climate change values. User that would like to combine observed climate (at a fix site) with
climate projections, can use the values of the last block and apply them to the observations. In
the case of precipitation, the delta values are in percent (future-baseline/baseline)*100.
5. Future values for Hadley are available only for 2071-2099 period, while for Echam are for
1991-2099. In the later, the year 2015 is not available due some problems with the experiments.
1 In this line, the indication 61_90 is wrong. The correct period is 1961-1989 as we state above
Table 1. Countries included in the PRECIS exported files
1
Antigua and Barbuda
2
Bahamas
3
Barbados
4
Belize
5
Cuba
6
Dominican Republic
7
Dominica
8
Grenada
9
Guadalupe
10
Guyana
11
Haiti
12
Jamaica
13
Martinique
14
St. Kits and Nevis
15
St. Lucia
16
St. Vincent and Grenadines
17
Trinidad and Tobago
18
Turks and Caicos
Table 1. Variable codes and description
Code
Description
03236
Surface mean temperature at 1.5 meters (Celsius degrees)
03236.max
Surface maximum temperature at 1.5 meters (Celsius degrees)
03236.min
Surface minimum temperature at 1.5 meters (Celsius degrees)
03245
Relative humidity (%)
03249
Wind speed at 10 meters (m/s)
05216
Precipitation (mm)
16222
Sea level pressure (hPa)
Figure 1. Directory structure of the PRECIS exported files