End of Practical Session 3
Congratulations! You have completed Session 3!
If you have extra time, you may want to try these additional METplus exercises. The answers are found on the next page.
EXERCISE 3.1: accum_3hr - Build a 3 Hour Accumulation Instead of 6
Instructions: Modify the METplus configuration files to build a 3 hour accumulation instead of a 6 hour accumulation from forecast data using pcp_combine in the HREF MEAN vs. MRMS QPE example. Then compare 3 hour accumulations in the forecast and observation data with grid_stat.
Copy your custom configuration file and rename it to qpf-ensemble.accum_3hr.conf for this exercise.
cp qpf-ensemble.output.conf qpf-ensemble.accum_3hr.conf
Open hrefmean-vs-mrms-qpe.conf (qpf) to remind yourself how fields are defined in METplus
Open qpf-ensemble.accum_3hr.conf with an editor and changes values.
HINT: There is a variable in the observation data named P03M_NONE that contains a 3 hour accumulation.
You should also change OUTPUT_BASE to a new location so you can keep it separate from the other runs.
OUTPUT_BASE = {ENV[METPLUS_TUTORIAL_DIR]}/output/exercises/accum_3hr
Rerun master_metplus passing in your new custom config file for this exercise
Review the log file. You should see Pcp-Combine read 3 files and run Grid-Stat comparing both 3 hour accumulations.
DEBUG 1: Reading data (name="P01M_NONE"; level="(0,*,*)";) from input file: /path/to/METplus_Data/qpf/uswrp/HREFv2_Mean/native/20170621/hrefmean_2017062100f024.nc
DEBUG 1: Reading data (name="P01M_NONE"; level="(0,*,*)";) from input file: /path/to/METplus_Data/qpf/uswrp/HREFv2_Mean/native/20170621/hrefmean_2017062100f023.nc
DEBUG 1: Reading data (name="P01M_NONE"; level="(0,*,*)";) from input file: /path/to/METplus_Data/qpf/uswrp/HREFv2_Mean/native/20170621/hrefmean_2017062100f022.nc
DEBUG 1: Creating output file: /path/to/tutorial/output/exercises/accum_3hr/uswrp/HREFv2_Mean/bucket/20170622/hrefmean_2017062200_A03.nc
DEBUG 2: Writing output variable "APCP_03" for the "sum" of "P01M_NONE(0,*,*)".
...
DEBUG 2: Processing APCP_03(*,*) versus P03M_NONE(0,*,*)...
Go to the next page for the solution to see if you were right!
EXERCISE 3.2: input_1hr - Force Pcp-Combine to only use 1 hour accumulation files
Instructions: Modify the METplus configuration files to force Pcp-Combine to use six 1 hour accumulation files instead of one 6 hour accumulation file of observation data in the PHPT vs. StageIV GRIB example.
Tip: Recall from the QPF presentation that METplus used a 6 hour observation accumulation file as input to Pcp-Combine to build a 6 hour accumulation file for the example where forecast lead = 6.
From the log output:
DEBUG 1: Reading data (name="APCP"; level="A6";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090418.06h
DEBUG 2: Skipping 399779 of 987601 grid points which do not meet the valid data threshold (1).
DEBUG 1: Creating output file: /path/to/tutorial/output/qpf-prob/uswrp/StageIV_grib/bucket/20160904/ST4.2016090418_A06h
DEBUG 2: Writing output variable "APCP_06" for the "sum" of "APCP/A6".
Copy your custom configuration file and rename it to qpf-prob.input_1hr.conf for this exercise.
cp qpf-prob.output.conf qpf-prob.input_1hr.conf
Open phpt-vs-s4grib.conf to remind yourself how fields are defined in METplus
Open qpf-prob.input_1hr.conf with an editor and add the extra information.
HINT 1: The variables that you need to add must go under the [config] section.
HINT 2: The FCST_PCP_COMBINE_INPUT_LEVEL and OBS_PCP_COMBINE_INPUT_LEVEL variables set the accumulation interval that is found in grib2 input data for forecast and observation data respectively.
You should also change OUTPUT_BASE to a new location so you can keep it separate from the other runs.
OUTPUT_BASE = {ENV[METPLUS_TUTORIAL_DIR]}/output/exercises/input_1hr
Rerun master_metplus passing in your new custom config file for this exercise
Review the log file to verify that six 1 hour accumulation files were used to generate the file valid at 2016090418. You should see output similar to the following in the log file:
DEBUG 1: Reading data (name="APCP"; level="A1";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090418.01h
DEBUG 1: Reading data (name="APCP"; level="A1";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090417.01h
DEBUG 1: Reading data (name="APCP"; level="A1";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090416.01h
DEBUG 1: Reading data (name="APCP"; level="A1";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090415.01h
DEBUG 1: Reading data (name="APCP"; level="A1";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090414.01h
DEBUG 1: Reading data (name="APCP"; level="A1";) from input file: /path/to/METplus_Data/qpf/uswrp/StageIV/20160904/ST4.2016090413.01h
DEBUG 2: Skipping 480079 of 987601 grid points which do not meet the valid data threshold (1).
DEBUG 1: Creating output file: /path/to/tutorial/output/exercises/input_1hr/uswrp/StageIV_grib/bucket/20160904/ST4.2016090418_A06h
DEBUG 2: Writing output variable "APCP_06" for the "sum" of "APCP/A1".
Go to the next page for the solution to see if you were right!
