2D Wave Spectra

I'm trying to get 2D wave spectra for a region of ocean using the following query:

'class': 'ea',
'date': '2003' + '-' + '02' + '-20/to/' + '2003' + '-' + '03' + '-01',
'direction': '1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24',
'domain': 'g',
'expver': '1',
'frequency': '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',
'number': '0/1/2/3/4/5/6/7/8/9',
'param': '251.140',
'stream': 'ewda',
'time': '00:00:00/03:00:00/06:00:00/09:00:00/12:00:00/15:00:00/18:00:00/21:00:00',
'area': str(maxLat) + '/' + str(maxLon) + '/' + str(minLat) + '/' + str(minLon), # North, West, South, East. Default: global
'grid': '0.5/0.5', # Latitude/longitude. Default: spherical harmonics or reduced Gaussian grid
'type': 'an',
'format': 'netcdf', # Output needs to be regular lat-lon, so only works in combination with 'grid'!
}, 'ISSM_Trial_ERA5_Data_NEW.nc')

I get back a 6 dimensional array that contains date, lat, lon, direction, frequency, and ensemble. I was expecting to get a single spectral density for each combination of date, lat, lon, direction and frequency. I'm not sure what the 10 ensemble values are. Do I need to do something with these 10 ensemble values to get the spectral desity? Thanks in advance for any assistance you can provide.



here some guidelines for 2D wave spectra data:

ERA5: data documentation - Wave spectra




I'm very sorry to disturb you,I want to ask you a question about downloading 2D wave spectra,and I want to download netcdf format,it is my script:

# import cdsapi
# c = cdsapi.Client()
# c.retrieve('reanalysis-era5-complete', {
# 'class': 'ea',
# 'date': '2018-04-25',
# 'direction': '1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24',
# 'domain': 'g',
# 'expver': '1',
# 'frequency': '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',
# 'param': '251.140',
# 'stream': 'wave',
# 'time': '00:00:00/01:00:00/02:00:00/03:00:00/04:00:00/05:00:00/06:00:00/07:00:00/08:00:00/09:00:00/10:00:00/11:00:00/12:00:00/13:00:00/14:00:00/15:00:00/16:00:00/17:00:00/18:00:00/19:00:00/20:00:00/21:00:00/22:00:00/23:00:00',
# 'type': 'an',
# 'format':'netcdf',
# }, 'ERA-spec_20180425.nc')

but ,when I queued for more than 10hours ,there is an error:

The request you have submitted is not valid

Reason: reduced_ll - not on a regular lat/lon grid or on a regular Gaussian grid. Exiting.

So ,I want to know,If is ERA5 unable to download netcdf 2D wave spectra?if it can be downloaded,How to modify the script?

Thanks very much!

I think you need to specify a regular grid. In my case I use a half degree in latitude and longitude. Try adding the line:

'grid': '0.5/0.5', 

thanks very much,I have previously specified a grid:'1*1°‘.I try it again.