ERA5 dataset

[charleshelms]

Hi all,
Has anyone managed to get era52arl working when downloading from "new" (circa 2018) Copernicus system? I had successfully converted ERA5 data to HYSPLIT when I downloaded ERA5 from the old MARS system circa 2017. The error I get is the same "latitudeOfFirstGridPointInDegrees" error that is discussed in this thread. Looking in the grib files, it appears that the variable exists in the files. I've included the python code I used to retrieve one of the files below:

#!/MYPATH/anaconda3/bin/python
import cdsapi
c = cdsapi.Client()
c.retrieve('reanalysis-era5-complete', {
'class': 'ea',
'date':'2013-09-05',
'expver': '1',
'levelist': '10/20/30/50/70/100/125/150/175/200/225/250/300/350/400/450/500/550/600/650/700/750/775/800/825/850/875/900/925/950/975/1000',
'levtype': 'pl',
'param': '60.128/75.128/76.128/129.128/130.128/131/132/133.128/135.128/138.128/155.128/157.128/203.128/246.128/247.128/248.128',
'stream': 'oper',
'time': '00:00:00',
'type': 'an',
'area': [50, -105, 0, -10],
'format':'grib'
}, 'era5_atlantic_201309050000')

In theory, I suppose I could go back to using the MARS system, but it seems like the Copernicus system is the preferred way to retrieve the data, so I'd like to get this working with that data if at all possible.

Thanks in advance,
Chip Helms

[alicec]

Can you make sure that you are using the most up to date era52arl code?
You can get it from github as well as the lastest HYSPLIT release.
https://github.com/amcz/hysplit_metdata

I have also added some sample code in the README.
For the pressure level data I am using the 'reanalysis-era5-pressure-levels'
rather than 'reanalysis-era5-complete' although I need to use the latter to get the ensemble data
and it should work for the pressure level data as well.

Can you add the code you are using to get the surface data
and the command for the conversion?

[alicec]

I reproduced your problem by downloading files using the request code that you have posted.
It looks like your request results in a file with
gridType = sh
please modify your request so
gridType = regular_ll

See some examples of requests at
https://github.com/amcz/hysplit_metdata

[charleshelms]

Sorry for the delayed response (I didn't notice that the forum thread went onto a second page )

I managed to get data that era52arl found agreeable based on the examples in the github readme file. That said, I suspect the cause of my issues might actually be down to me using 'cat' to combine the single-time grib files I downloaded into one combined grib file expected by era52arl instead of using grib_copy (I could have sworn 'cat' was a valid way to combine grib files, but perhaps it's a case of being good enough for some uses but not for all, or perhaps I'm just misremembering). As far as specifying 'gridType' as 'regular_ll', I wasn't able to get that to work, but after digging around it might be that I should have specified 'typeOfGrid', although I haven't had a chance to test that. Either way, I've included examples of the python scripts that I used to download the individual files that I then combined with grib_copy into three files (one each for the pressure levels, the surface analysis, and the surface forecast). One final note, I haven't had the chance to run the trajectory model on the converted files (and I probably won't have time to do so for a couple weeks), but I wanted to reply to the thread in a semi-timely manner. I did notice that I kept getting the following warning:
"WARNING, 2d forecast does not have time 13 9 5 9"
but I don't expect it to be an issue as the last time I'm interested in is 0000 UTC 5 September 2013.

Thanks again for your help!

Here are the examples of the python scripts I used:

::::::::::::::
tmpera5grab_pl_an.py
::::::::::::::
#!/PATH/TO/anaconda3/bin/python
import cdsapi
c = cdsapi.Client()
c.retrieve('reanalysis-era5-pressure-levels',
{
'variable' : ['temperature','u_component_of_wind','v_component_of_wind','vertical_velocity','relative_humidity','geopotential'],
'pressure_level':['10','20','30','50','70','100','125','150','175','200','225','250','300','350','400','450','500','550','600','650','700','750','775','800','825','850','875','900','925','950','975','1000'],
'product_type' : 'reanalysis',
'grid' : '0.25/0.25',
'date':'2013-09-05',
'time': '00:00:00',
'type': 'an',
'area': [50, -105, 0, -10],
'format':'grib'
}, 'era5_atlantic_201309050000')
::::::::::::::
tmpera5grab_sfc_an.py
::::::::::::::
#!/PATH/TO/anaconda3/bin/python
import cdsapi
c = cdsapi.Client()
c.retrieve('reanalysis-era5-single-levels', {
'variable' : ['2m_temperature','10m_u_component_of_wind','10m_v_component_of_wind','surface_pressure','boundary_layer_height','geopotential','friction_velocity'],
'product_type' : 'reanalysis',
'grid' : '0.25/0.25',
'type': 'an',
'date':'2013-09-05',
'time': '00:00:00',
'area': [50, -105, 0, -10],
'format':'grib'
}, 'era5_sfc_an_atlantic_201309050000')
::::::::::::::
tmpera5grab_sfc_fc.py
::::::::::::::
#!/PATH/TO/anaconda3/bin/python
import cdsapi
c = cdsapi.Client()
c.retrieve('reanalysis-era5-single-levels', {
'variable' : ['2m_temperature','10m_u_component_of_wind','10m_v_component_of_wind','surface_pressure','boundary_layer_height','geopotential','friction_velocity'],
'product_type' : 'reanalysis',
'grid' : '0.25/0.25',
'type': 'fc',
'date':'2013-09-04',
'time': '18:00:00',
'area': [50, -105, 0, -10],
'format':'grib'
},
'era5_sfc_fc_atlantic_201309041800')

[alicec]

Thanks for updating and sharing your scripts.

A few thoughts.

With the new cdsapi you do not need to have separate files for the analysis and forecast surface data.
The new api allows you to retrieve both types of variables into the same file (The old api did not).
The era52arl program can still ingest separate files, but you can also just give it one file for the surface fields.
The -f option is optional.
I strongly suggest you use a single file for the surface fields.

The warning you are getting relates to the use of the separate forecast file.
With the old api, the forecast data had to be retrieved separately and then the conversion program needed to calculate the
date the data was valid for by taking into account the forecast step. The new api automatically packages the forecast
data in with the analysis data so this does not need to be done.

specifying
'grid':'0.25/0.25'
results in the regular_ll grid type.
https://confluence.ecmwf.int/display/CK ... +reference

[Charlie]

Hi everyone!

As you well know, ERA5 has been updated! And I need to know if the era52arl.f program still works with the ERA5 update. I would appreciate any information.

Best regards!

Charlie

[chaojixiaoniuniu]

I'm not sure I understand the trouble you are having with downloading the files. How are you trying to download them?
Are you using the python code or other way? Can you describe this problem in more detail?

The reason you are getting the error from era52arl is that you need to input at least 2 grib files - one
for the surface fields and one form the pressure level fields. The default name for the pressure level fields
is DATA.GRIB. The default name for the surface fields is SFC.GRIB. You can specify other names for these with the -i and -a options (see below).
The error you are getting is because it is not finding the SFC.GRIB file.
After it says Allocating igrib, you should also get a message that says Allocating agrib.

a default era52arl.cfg will be created if none exists or
alternate name is not specified with the -d option.
This file specifies variables and pressure levels to be written.
-d[decoding configuration file {name | create era52arl.cfg}]
-i[input grib1 file with pressure level fields name {DATA.GRIB}]
-a[input grib1 analysis surface fields name {SFC.GRIB}]
-f[input grib1 forecast surface fields name {SFC2.GRIB}]
-o[output data file name {DATA.ARL}]
-v[verbose mode {False}]

Hello, Alicec. i can complie the era52arl program, but when i use the bash below
./era52arl_debug -i pressure_level.grib -a surface_level.grib -o output.arl
i face the problem, the fault is below
(eccodes_build) [@localhost era52arl]$ ./era52arl_debug -o output.arl
NARG 2

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:

Could not print backtrace: unrecognized DWARF version in .debug_info at 6

Could not print backtrace: unrecognized DWARF version in .debug_info at 6
#0 0x7fc13621adfd in ???
#1 0x7fc13621a013 in ???
#2 0x7fc135b643ff in ???
#3 0x7fc135c98fa2 in ???
#4 0x7fc136431f5a in ???
#5 0x7fc13621a7c9 in ???
#6 0x56078487a4c2 in era52arl
at /home//era52arl/era52arl.f:374
#7 0x56078488908e in main
at /home//era52arl/era52arl.f:102
Segmentation fault (core dumped)
Can you help me ? Is so, thanks very much!