Index: For_developers/Sphinx/source/Documentation/Overview/prog_flow.rst
===================================================================
--- For_developers/Sphinx/source/Documentation/Overview/prog_flow.rst	(revision b1674ed9a3275890229aaf2e958f2ea7db4f28ac)
+++ For_developers/Sphinx/source/Documentation/Overview/prog_flow.rst	(revision f20342a474e36967cf41b6e992ab0fd6992624c4)
@@ -1,4 +1,4 @@
 ************
-Program Flow
+Program flow
 ************
 
@@ -16,15 +16,15 @@
 .. figure:: ../../_files/submit.png    
     
-    Overview of the call of python's ``submit.py`` script and raw sequence of working steps done in ``flex_extract``.
+    Overview of the call of the``submit.py`` Python script and raw sequence of work steps in ``flex_extract``.
 
     
-The ``submit.py`` Python program is called by the Shell script ``run.sh`` or ``run_local.sh`` and accomplish the following steps: 
+The ``submit.py`` Python script is called by the shell script ``run.sh`` or ``run_local.sh`` and accomplishes the following steps: 
 
-    1. Setup the control data:
-        It gets all command-line and ``CONTROL`` file parameters as well as optionally the ECMWF user credentials. Depending the :doc:`app_modes`, it might also prepare a job script which is then send to the ECMWF queue. 
-    2. Retrieves data from MARS:
-        It creates and sends MARS-requests either on the local machine or on ECMWF server, that receives the data and stores them in a specific format in GRIB files. If the parameter ``REQUEST`` was set ``1`` the data are not received but a file ``mars_requests.csv`` is created with a list of MARS requests and their settings. If it is set to ``2`` the file is created in addition to retrieving the data. The requests are created in an optimised way by splitting in time, jobs  and parameters.   
-    3. Post-process data to create final ``FLEXPART`` input files:
-        After all data is retrieved, the disaggregation of flux fields (`see here <../disagg.html>`_ ) is done as well as the calculation of vertical velocity (`see here <../vertco.html>`_) by the Fortran program ``calc_etadot``. Eventually, the GRIB fields are merged together such that a single grib file per time step is available with all fields for ``FLEXPART``. Since model level fields are typically in *GRIB2* format whereas surface level fields are still in *GRIB1* format, they can be converted into GRIB2 if parameter ``FORMAT`` is set to *GRIB2*. Please note, however, that older versions of FLEXPART may have difficulties reading pure *GRIB2* files since some parameter IDs change in *GRIB2*. If the retrieval is executed remotely at ECMWF, the resulting files can be communicated to the local gateway server via the ``ECtrans`` utility if the parameter ``ECTRANS`` is set to ``1`` and the parameters ``GATEWAY``, ``DESTINATION`` have been set properly during installation. The status of the transfer can be checked with the command ``ecaccess-ectrans-list`` (on the local gateway server). If the script is executed locally the progress of the script can be followed with the usual Linux tools.
+    1. Setup of control data:
+        Command-line and ``CONTROL``-file parameters are read, as well as (optionally) the ECMWF user credentials. Depending the :doc:`app_modes`, a job script might be prepared which is then sent to the ECMWF queue. 
+    2. Retrieval of data from MARS:
+        MARS requests are created either on the local machine or on the ECMWF server and then submitted which retrieve the data and store them in GRIB files. If the parameter ``REQUEST`` was set ``1``, the data are not retrieved and instead a file ``mars_requests.csv`` is created, which contains a list of the MARS requests and their settings. If ``REQEST`` is set to ``2``, the csv file is created in addition to retrieving the data. The requests are created in an optimised way by splitting with respect to time, jobs  and parameters.   
+    3. Post-processing of data to create final ``FLEXPART`` input files:
+        After all data have been retrieved, flux fields are disaggregated (`see here <../disagg.html>`_ ) and the vertical velocity is calculated (`see here <../vertco.html>`_) by the Fortran program ``calc_etadot``. Finally, the GRIB fields are merged into a single grib file per time step containing all the fields for ``FLEXPART``. Since model-level fields are typically in *GRIB2* format, whereas surface-level fields are still in *GRIB1* format, they will be converted into GRIB2 if parameter ``FORMAT`` is set to *GRIB2*. Please note, however, that older versions of FLEXPART may have difficulties to read these *GRIB2* files since some parameter IDs have been change in *GRIB2*. If the retrieval is executed remotely at ECMWF, the resulting files will be sent to the local gateway server via the ``ECtrans`` utility if the parameter ``ECTRANS`` is set to ``1`` and the parameters ``GATEWAY``, ``DESTINATION`` have been set properly during installation. The status of the transfer can be checked with the command ``ecaccess-ectrans-list`` (on the local gateway server). If the script is executed locally, the progress of the script can be followed with the usual Linux tools.
 
 
@@ -33,5 +33,5 @@
 ========================================
 
-More details on how different the program flow is for the different :doc:`app_modes` is sketched in the following diagrams:  
+The following diagrams show how different the program flow is for the different :doc:`app_modes`:  
 
 +-------------------------------------------------+------------------------------------------------+
