Index: preproc/python/README.md
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+# README #
+
+This documentation shows how to use these python scripts to extract ECMWF ERA-Interim data and generate WINDFIELDS for running FLEXPART. 
+
+### Overview ###
+
+To run FLEXPART with ECMWF ERA-Interim data, you first need to retrieve ECMWF ERA-Interim GRIB fields and generate FLEXPART WINDFIELDS to run FLEXPART.
+
+The two main programs are called respectively `getEIdata.py` and `prepareFLEXPART.py`. 
+
+To get the usage of these programs, use `-h` option:
+
+`getEIdata.py `-h`
+
+Optional arguments are mentionned in squared brackets. 
+
+* `getEIdata.py`
+
+This program allows you to download ECMWF ERA-Interim data from ECMWF using [ecmwfapi](https://software.ecmwf.int/wiki/display/WEBAPI/ECMWF+Web+API+Home). 
+It requires `ecmwfapi` python library (see Requirements below). Check with your local IT group as it may be already available.
+
+`
+Usage: getEIdata.py --start_date=YYYYMMDD [--end_date=YYYYMMDD] [--times=tt1/tt2/tt3] [--levels=nlevels]
+                                                  [--area=north/west/south/east]  [--outputdir=output_directory]
+
+Options:
+  -h, --help            show this help message and exit
+  --start_date=start_date
+                        start date YYYYMMDD
+  --end_date=end_date   end_date YYYYMMDD
+  --times=times         times such as 00/12
+  --levels=levels       number of vertical levels
+  --area=area           area defined as north/west/south/east with default
+                        90.0/-179.0/-90.0/180.0
+  --outputdir=outputdir
+                        root directory for storing output files
+`
+
+* `prepareFLEXPART.py`
+
+This program allow you to generate FLEXPART WINDFIELDS (inputs for FLEXPART). It requires python interface to grib_api and `CONVERT2` program (located in `src` directory with instruction on how to compile it). You also need to provide a namelist for CONVERT2 (see test_1).
+
+`
+Usage: prepareFLEXPART.py --start_date=YYYYMMDD [--end_date=YYYYMMDD] [--namelist=namelist_for_convert] [--inputdir=input_root_directory] [--outputdir=output_directory]
+
+Options:
+  -h, --help            show this help message and exit
+  --start_date=start_date
+                        start date YYYYMMDD
+  --end_date=end_date   end_date YYYYMMDD
+  --namelist=namelist   namelist used for converting
+  --inputdir=inputdir   root directory for reading input files
+  --outputdir=outputdir
+                        root directory for storing output files
+
+`
+### Requirements ###
+
+| Python Support        |
+|----------------------:| 
+| python                | [http://www.python.org](http://www.python.org)  | We have use [python Anaconda](https://store.continuum.io/cshop/anaconda/) for our testings
+| python-numpy          | [http://www.numpy.org/](http://www.numpy.org/)  | Not necessary if you have installed python Anaconda
+| ecmwfapi              | [https://software.ecmwf.int/wiki/display/WEBAPI/ECMWF+Web+API+Home](https://software.ecmwf.int/wiki/display/WEBAPI/ECMWF+Web+API+Home) | You also need to install your API key (as explained in the documentation)
+| Utilities             |
+|----------------------:| 
+|  grib-api             | [https://software.ecmwf.int/wiki/display/GRIB/Home](https://software.ecmwf.int/wiki/display/GRIB/Home) | Make sure you install GRIB-API with JPEG support and python GRIB-API.
+|----------------------:| 
+| FLEXPART programs     | to run these programs (prepareFLEXPART.py), you need to compile CONVERT2 program (located in preproc/src). See separate README file to get instructions on how to compile this code.
+|----------------------:| 
+
+
+### Installation ###
+
+*  Environment
+
+At UIO, Red Hat 6 Linux systems (64 bits) were used for testing. We use the [Module package](http://modules.sourceforge.net/) to set-up user environment.
+
+* Getting the source code
+In the directory of your choice:
+
+`
+git clone git@bitbucket.org:flexpart/flexpart.git
+`
+This command will create a subdirectory called flexpart: it contains the latest FLEXPART version.
+
+Set then environment variable `FLEXPART_HOME`:
+
+** Korn-shell or Bash users:
+`
+cd flexpart
+export FLEXPART_HOME=$PWD
+`
+
+** C-shell users:
+
+`
+cd flexpart
+setenv FLEXPART_HOME=$PWD
+`
+
+* Installation
+
+Make sure your first generate `CONVERT2` program (see separate instructions in `preproc/src`).
+
+Users need to be able to execute prepareFLEXPART.py and getEIdata.py so make sure they have the correct unix permissions:
+
+`
+cd preproc/python
+chmod uog+rx getEIdata.py prepareFLEXPART.py
+`
+
+These two programs must be in the user PATH. At UIO this is done automatically when loading flexpart. If not, you would need to do the following:
+
+** Korn-shell or Bash users:
+`
+export PATH=$FLEXPART_HOME/preproc/python:$PATH
+`
+
+** C-shell users:
+
+`
+setenv PATH $FLEXPART_HOME/preproc/python:$PATH
+`
+
+Where `$FLEXPART_HOME` is the directory where FLEXPART 
+
+* Testing your installation
+
+First check that grib-api python interface is correctly installed on your platform:
+`
+python
+>>> from gribapi import *
+>>>
+`
+Use `CTRL-D` to quit python.
+
+Then check that `ecmwfapi` is properly installed:
+`
+python
+>>> from ecmwfapi import *
+>>>
+`
+
+If the two previous tests were successful, you can run `tests/preproc` (See separate instructions in `tests/preproc`). 
+
+If any of these two tests fail, this probably means that either `ecmwfapi` or `grib-api` have not been installed properly. 
+
+Please report any problems.
+
+###  Installation FAQ ###
+
