Import data on unstructured grid

1

Hello,

I have data stored in a NetCDF file on its native, unstructured model grid. Here is a snapshot of how the data is organized and formatted:

dimensions:
	ncol = 316010 ;
	time = UNLIMITED ; // (12 currently)
	nbnd = 2 ;
	chars = 8 ;
	lev = 58 ;
	ilev = 59 ;
	trop_pref = 58 ;
	trop_prefi = 59 ;
	trop_cld_lev = 58 ;
variables:
	double lat(ncol) ;
		lat:long_name = "latitude" ;
		lat:units = "degrees_north" ;
	double lon(ncol) ;
		lon:long_name = "longitude" ;
		lon:units = "degrees_east" ;
	double areawt(ncol) ;
		areawt:long_name = "physics column area weight" ;
	double area(ncol) ;
		area:long_name = "physics column areas" ;
	double lev(lev) ;
		lev:long_name = "hybrid level at midpoints (1000*(A+B))" ;
		lev:units = "hPa" ;
		lev:positive = "down" ;
		lev:standard_name = "atmosphere_hybrid_sigma_pressure_coordinate" ;
		lev:formula_terms = "a: hyam b: hybm p0: P0 ps: PS" ;
	double hyam(lev) ;
		hyam:long_name = "hybrid A coefficient at layer midpoints" ;
	double hybm(lev) ;
		hybm:long_name = "hybrid B coefficient at layer midpoints" ;
	double P0 ;
		P0:long_name = "reference pressure" ;
		P0:units = "Pa" ;
	double ilev(ilev) ;
		ilev:long_name = "hybrid level at interfaces (1000*(A+B))" ;
		ilev:units = "hPa" ;
		ilev:positive = "down" ;
		ilev:standard_name = "atmosphere_hybrid_sigma_pressure_coordinate" ;
		ilev:formula_terms = "a: hyai b: hybi p0: P0 ps: PS" ;
	double hyai(ilev) ;
		hyai:long_name = "hybrid A coefficient at layer interfaces" ;
	double hybi(ilev) ;
		hybi:long_name = "hybrid B coefficient at layer interfaces" ;

VAPOR is unable to read in the dataset in its current form.

I’m wondering 1) if/how I can modify the formatting so VAPOR can understand the data and 2) if/how VAPOR handles hybrid sigma-pressure coordinates?

Any help or insight is greatly appreciated!

Thanks,
Nick F.

2

Hi Nick,

VAPOR only supports the unstructured data standards from MPAS and UGRID. We provide some samples here. If you can get your data to match either of those types, you should be able to import them as those types.

VAPOR also does support hybrid sigma-pressure coordinates by internally converting those values to meters above ground level.

Hope that helps and let me know if you have any followup questions.

-Scott