PUTTING AN END TO NUCLEAR EXPLOSIONS
Disclaimer: The views expressed on this poster are those of the author and do not necessarily re$ect the view of the CTBTO
ECMWF data sets as input for the ATM FLEXPART prepared by
a new version of the flex_extract tool
Anne Philipp ¹·², Leopold Haimberger ¹ and Petra Seibert ³
¹ Department of Meteorology and Geophysics, University of Vienna, Vienna, Austria
² Aerosol & Environmental Physics, University of Vienna, Vienna, Austria
³ Institute of Meteorology, University of Natural Resources and Life Sciences, Vienna, Austria
T2.4-P20
ABSTRACT
An open-source tool called flex_extract has been developed over
many years, partly on behalf of the CTBTO/PTS, to retrieve and
prepare meteorological data from the European Centre for
Medium-Range Weather Forecasts (ECMWF) MARS archive for
driving the Lagrangian particle transport model FLEXPART ([1],[3],
[5],[6]) or the WRF model. These data fields describe the state of
the atmosphere relevant for transport modelling.
Its functionality includes the generation and execution of MARS
requests, calculation of the vertical winds for FLEXPART, and
transformation to a latitude-longitude grid. Additionally, it
disaggregates accumulated flux data, such as precipitation, in
order to get the quasi-instantaneous fluxes which FLEXPART
requires, and prepares the final FLEXPART input files.
In 2018, several changes effected the ECMWF processing system,
such as the replacement of grib_api by ecCodes, of emoslib by the
new interpolation library MARS-MIR, and also in the Web API
access. Furthermore, more data can now be accessed by non-
member-state users. The latest reanalysis, ERA5, with many
improvements compared to the previous ERA-Interim, is currently
available from 1979 on.
The diversity of data sets, the possible combinations of MARS
request settings and ways of accessing MARS can be confusing
for less experienced users. Therefore, an overview of the available
ECMWF data sets and the ways how they can be accessed with
the latest version of flex_extract is presented.
REFERENCES
[1] Anonymous (2019): The official FLEXPART web site,
https://www.flexpart.eu/
[2] MARS user documentation.
https://confluence.ecmwf.int/display/UDOC/MARS+user+documentation
, Accessed: 19.06.2019
[3] Pisso, I.; Sollum, E.; Grythe, H.; Kristiansen, N.; Cassiani, M.;
Eckhardt, S.; Arnold, D.; Morton, D.; Thompson, R. L.; Groot Zwaaftink,
C. D.; Evangeliou, N.; Sodemann, H.; Haimberger, L.; Henne, S.;
Brunner, D.; Burkhart, J. F.; Fouilloux, A.; Brioude, J.; Philipp, A.;
Seibert, P.; and Stohl, A. (2019): The Lagrangian particle dispersion
model FLEXPART version 10.3, Geosci. Model Dev. Discuss.,
https://doi.org/10.5194/gmd-2018-333, in review.
[4] Baudouin Raoult (-): Architecture of the new MARS server. ECMWF
article
[5] Stohl, A.; M. Hittenberger and G. Wotawa (1998): Validation of the
Lagrangian particle dispersion model FLEXPART against large scale
tracer experiments, Atmos. Environ. 32, 4245-4264.
[6] Stohl, A., C. Forster, A. Frank, P. Seibert, and G. Wotawa (2005):
Technical Note : The Lagrangian particle dispersion model FLEXPART
version 6.2, Atmos. Chem. Phys. 5, 2461-2474.
How to get flex_extract
Since it is not yet officially released, it can currently be
cloned from the dev branch of the git repository on
https://flexpart.eu for testing purposes. An extensive
online documentation is currently in process and will
soon be available on https://flexpart.eu along with the
software package .
Support
●
FLEXPART’s community website and ticket
system: https://flexpart.eu
●
flex_extract information:
https://www.flexpart.eu/wiki/FpInputMetEcmwf
●
Git repository:
https://www.flexpart.eu/browser/flex_extract.git
●
Mailing list: flexpart[at]lists.univie.ac.at
Access modes with flex_extract
MARS archive
MARS is the ECMWF’s Meteorological Archival and Retrieval
System. The data in this system are meteorological fields and
observation data, the smallest addressable object. Additionally,
metadata describe the place where the data is stored.
The single fields are grouped together into logical entities, such as
“a forecast”, also called archive object. To address these fields or
objects the metadata or attributes are organised in a tree fashion,
such as this one for an operational analysis in february 1996:
Parameters
Model level U, V, T, Q, ETADOT,
(CIWC+CLWC=QC)
Surface level LNSP, MSL, 10u, 10v, 2T, 2D,
SD, TCC, SR, Z, SDOR, LSM
Flux data LSP, CP, SSHF, EWSS, NSSS
Archive object
for “a forecast”
Operational
ERA-Interim
CERA-20C
ERA5
ERA-Interim
CERA-20C
ERA5
Member state user
Datasets accessible through flex_extract
Public user
Not all meteorological fields and time steps are available for
public users. This is taken into account in the sample
CONTROL files according to the datasets.
Hypercube:
Example sketch of all fields
of all forecasts of an
Ensemble prediction system
for a month
MARS access for availability check
It might be useful or necessary to check for availability
of data in ECMWF’s MARS. Public users can use a web
mask to check on data or list available data at
https://apps.ecmwf.int/datasets/.
Member state users can check availability of data online
at https://apps.ecmwf.int/mars-catalogue/.
On ECMWF servers there are more possibilities to work
with MARS:
➔
retrieve – extract data by specifying the MARS
keywords
➔
compute – performs mathematical operations on
GRIB files
➔
list – checks if data specifying from MARS request is
available
➔
read – just reads data from GRIB files for manipulation
➔
write – writes selected data into files
Parameters controlling flex_extract
Flex_extract uses so-called “CONTROL” files to specify the
parameters for controlling the program flow and to generate the
MARS request. Some parameters in these CONTROL files are
specific for the MARS requests, others control internals of
flex_extract. The parameters are described in detail in the
documentation.
An example of a CONTROL file for the extraction of a single day
from the CERA-20C dataset is shown below:
START_DATE 20000908
DTIME 3
TYPE AN AN AN AN AN AN AN AN
TIME 00 03 06 09 12 15 18 21
STEP 00 00 00 00 00 00 00 00
ACCTYPE FC
ACCTIME 18
ACCMAXSTEP 24
CLASS EP
DATASET cera20c
STREAM ENDA
NUMBER 0
GRID 1.
LEFT -179.
LOWER -90.
UPPER 90.
RIGHT 180.
LEVELIST 1/to/91
RESOL 106
ETA 1
CWC 1
PREFIX CEpub
This would result in 8
FLEXPART input files, one
per time step:
CEpub00090800
CEpub00090803
CEpub00090806
CEpub00090809
CEpub00090812
CEpub00090815
CEpub00090818
CEpub00090821
run.sh
CONTROL file
flex_extract
FLEXPART
input files
A public dataset is
explicitly requested by
using the additional
keyword “DATASET”.
Program flow
Flex_extract is used by first specifying the parameters in a
CONTROL file and by defining some parameters in the “run.sh”
script. Afterwards the “run.sh” script is started:
Table1: List of
most important
specifications
and differences
in the available
datasets.
FLEXPART parameters retrieved with
flex_extract
FLEXPART needs specific meteorological fields which are
extracted with flex_extract in any case. However, with the
additional keyword “ADDPAR” the user can extract more 2D
fields, with the only limit that they are not allowed to be
accumulated fields.
MARS
Modes Description
1.Remote Installation and execution on
ECMWF server; member state user
account
2.Gateway Installation and execution on local
gateway server; Job scripts send
by ecaccess to ECMWF server;
member state user account
3.Local
member
Installation and execution on local
machine; member state user
account
4.Local
public
Installation and execution on local
machine; registration as public
user; acceptance of each dataset
licenses needed
ECMWF
WebAPI
Services
Archive
catalogue
Public
datasets
Access
MARS
Access
public
datasets
CDS API
Services
Access
ERA5 in
MARS
Access
public ERA5
dataset
MARS
Public
user
Member
state user
Local
gateway
server
ECMWF server
2. Gateway
1. Remote
4. Local public
3. Local member
4
.
L
o
c
a
l
p
u
b
l
i
c
3. Local member
Member state user
Full access to
ECMWF data in
MARS. Registration
through Computing
Representative.
Public user
Limited access to
reanalysis data in
MARS through Web
API. Registration on
ECMWF website.
