WMO Non-Nuclear Environmental Response Activities
Backtracking Experiment - Participant Instructions
February 2008
1
Overview of the Experiment
The experiment will simulate a stationary release of a chemical contaminant near the coast of Europe, over a 72
hour period.
The simulated observations will be created by RSMC Exeter, by calculating by forward trajectory 6 hourly
sampling concentrations at a number of locations. Over a 72 hour period from the beginning of the experiment,
three summaries of the receptor details will be prepared (Days 1, 2 and 3). These three notifications of receptor
details will all be sent together to participating RSMCs soon after the experiment period ends.
Notification will be by e-mail and will be sent on Day 4, unless this is on a weekend, in which case the
notification will be sent the following week. Please note that this means that participating centres will need to
store the meteorological data necessary for backtracking for up to 7 days.
At the beginning of the experiment period participants will be informed by email. For example, we would have
issued the following on the 15 Oct: ‘The period of the exercise will cover 15 Oct to 18 Oct.'
At the end of the experiment period, participants will receive the notification of simulated receptor details in the
format as shown below, with a request for backward runs of 24 hours for Day 1, 48 hours for Day 2 and 72
hours for Day 3.
Participating centres will not need to respond immediately, but can carry out the backtracking runs when
convenient. The products to be generated for the 24 hr, 48 hr and 72 hr runs are:
 6 hour time integration concentration maps as images (gif, jpg, png)
 back trajectories for each receptor in image format (gif, jpg, png)
 SRS fields based on 6 hr output interval.
2
Technical Details
2.1
Example Notification
Notification will be sent during the week of 25 February 2008 by either matthew.hort@metoffice.gov.uk or by
claire.witham@metoffice.gov.uk.
====== REQUEST FOR SUPPORT ===== TEST: RSMC OCT 2007
#START
Source-receptor matrix results are requested for
007
detections
NUM LON LAT ID Measurement Start/stop time (YYYYMMDD hh)
001 12.6 55.7 RSMC07 20071016 0000 20071016 06
002 12.6 55.7 RSMC07 20071016 0600 20071016 12
003 12.6 55.7 RSMC07 20071016 1200 20071016 18
004 12.6 55.7 RSMC07 20071016 1800 20071017 00
005 18.7 54.4 RSMC10 20071016 0600 20071016 12
006 18.7 54.4 RSMC10 20071016 1200 20071016 18
007 18.7 54.4 RSMC10 20071016 1800 20071017 00
======================================================================
Please calculate backward to
20071015 00
#END
2.2
Back Run Setup Details
All times are UTC.
Negative Longitude indicates Western Hemisphere.
Output Domain:
Horizontal Grids (referenced to the centre of the grid box):
Coordinate system:
Long-Lat,
Number of long points (nx):
360
Number of lat points (ny):
360
Space between/size of long points/boxes: 0.25 degrees
Space between/size of lat points/boxes:
0.25 degrees
long-lat of centre of first ouput point/box: -45.0, 0.0 degrees
Vertical Grid:
Coordinate system:
Height of output grid point/box:
Output grid point/box centred at:
meters above ground level (agl)
150 m
75 m agl
Receptor Strength (i.e. Source strength for back run)
1 g/s
Species:
INERT-TRACER
Source/Receptor Dimensions:
dx=0
dy=0
dz = 0 - 150m above ground level
2.3
Output
For the duration of each forecast:
6 hour time integration concentration maps as images (gif, jpg, png)
Back trajectories for each receptor in image format (gif, jpg, png)
SRS fields based on 6 hr output interval
2.4
Transmission of Results:
Please FTP the SRS results to Roland Draxler at gus.arlhq.noaa.gov (user: wmoftp pass: test1029). The files should be
same format as those normally supplied to CTBTO: ascii and compressed (zip or gzip).
Please send an e-mail notification to Roland.Draxler@noaa.gov the upload has been completed. The account will be
disabled after the experiment.
Please send images (gif, jpg, png) to UK – email: matthew.hort@metoffice.gov.uk
Please note: 10 Mb limit per email – 140Mb limit for entire mail box.
If email is not possible please advise Matthew Hort.
2.5
Name,
RSM01,
RSM02,
RSM03,
RSM04,
RSM05,
RSM06,
RSM07,
RSM08,
RSM09,
RSM10,
RSM11,
RSM12,
RSM13,
RSM14,
RSM15,
RSM16,
RSM17,
RSM18,
RSM19,
RSM20,
RSM21,
RSM22,
RSM23,
RSM24,
RSM25,
RSM26,
RSM27,
RSM28,
Sensor Locations
Long., Lat
-3.0, 59.0
-6.0, 54.5
-3.7, 50.4
-15.0, 45.0
5.3, 60.4
18.1, 59.3
12.6, 55.7
13.4, 52.0
-18.0, 53.5
18.7, 54.4
2.3, 70.0
6.1, 49.6
-1.6, 47.2
-3.0, 43.2
-9.1, 38.7
2.6, 39.6
10.2, 36.8
11.2, 43.8
19.5, 47.5
27.6, 53.9
23.7, 38.0
30.7, 46.5
31.2, 30.1
-8.0, 31.6
-21.9, 64.2
19.0, 69.7
30.3, 59.9
37.6, 55.8