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You can use the MARS catalogue and the or Archive catalogue (for users without full MARS access) and the "View MARS request" to to get a MARS request and modify the keywords with the information that you need. Once you have the request prepared, you should replace RETRIEVE by by LIST and add the OUTPUT = COST keyword. Any post-processing keyword will be ignored by the LIST verb.
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Using the MARS catalogue, browse to the data you want to retrieve until you reach the final stage which gives a selection and several options: http://apps.ecmwf.int/mars-catalogue/?stream=enfo&levtype=sfc&time=00%3A00%3A00&expver=1&month=mar&year=2019&date=2019-03-01&type=pf&class=odod (or the same data selection in Archive catalogue).
For this particular case a different "Parameter", "Number" and "Step" can be selected for a specific date and time. All the fields you can choose in this page should be stored on the same tape file.
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| Tip |
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The size of the file that will be transferred to the system can be established by downloading a single field using the Post-processing keywords (usually GRID and AREA). Then multiply the size of the file obtained containing this single field by the total number of fields that you want to retrieve in a single request: number_of_fields=43500. |
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| Code Block | ||
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#!/bin/bash
#this example will filter the area of Europe (N/W/S/E) and interpolate the final fields to a lat/lon 0.5/0.5 degrees
AREA="73.5/-27/33/45"
GRID="0.5/0.5"
# fixed selection from the same block
STEP="0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/33/34/35/36/37/38/39/40/41/42/43/44/45/46/47/48/49/50/51/52/53/54/55/56/57/58/59/60/61/62/63/64/65/66/67/68/69/70/71/72/73/74/75/76/77/78/79/80/81/82/83/84/85/86/87/88/89/90/93/96/99/102/105/108/111/114/117/120/123/126/129/132/135/138/141/144/150/156/162/168/174/180/186/192/198/204/210/216/222/228/234/240/246/252/258/264/270/276/282/288/294/300/306/312/318/324/330/336/342/348/354/360,"
PARAMS="134.128/151.128/165.128/166.128/246.228/247.228"
NUMBER="1/to/50"
TIMES="0000"
YEAR="2019"
MONTH="03"
for y in ${YEAR}; do
for m in ${MONTH}; do
#get the number of days for this particular month/year
days_per_month=$(cal ${m} ${y} | awk 'NF {DAYS = $NF}; END {print DAYS}')
#date loop
for my_date in $(seq -w 1 ${days_per_month}); do
my_date=${YEAR}${m}${my_date}
#time lop
for my_time in ${TIMES}; do
cat << EOF > my_request_${my_date}_${my_time}.mars
RETRIEVE,
CLASS = OD,
TYPE = PF,
STREAM = ENFO,
EXPVER = 0001,
LEVTYPE = SFC,
GRID = ${GRID},
AREA = ${AREA},
PARAM = ${PARAMS},
DATE = ${my_date},
TIME = ${my_time},
STEP = ${STEP},
NUMBER = ${NUMBER},
TARGET = "enfo_pf_${my_date}_${my_time}.grib"
EOF
mars my_request_${my_date}_${my_time}.mars
if [ $? -eq 0 ]; then
rm -f my_request_${my_date}_${my_time}.mars
fi
done
done
done
done |
| Note |
|---|
You can use the multi-target feature in the TARGET keyword if you are using the full MARS client (from within ECMWF computing facilities). You can also use ecCodes to post-process the TARGET file afterwards. |
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