Ernst, atmosphere_hybrid_sigma_pressure_coordinate attribute was added to vertical pressure coordinate type variables. It uses the calculations described at: http://www.ecmwf.int/research/ifsdocs/DYNAMICS/Chap2_Discretization4.html#961180 Your sample file HIRLAMhybrid.grib, the vertical pressure coordinates don't seem correct to me according to the above documentation. The test file ECMWF.2008.09.07.T00Z.uad_HGrbF00.A08334081908 was used, it had 91 levels and it follow the above documentation and the a and b values matched table located at: http://www.ecmwf.int/products/data/technical/model_levels/model_def_91.html The release with the fixes will be available sometime mid September. Robb... Ticket Details =================== Ticket ID: KDK-897162 Department: Support netCDF Java Priority: Critical Status: Open