ok, try using full path name on variableAgg : <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2"> <aggregation dimName="time" type="joinNew"> <variableAgg name="All_Data/VIIRS-CBH-EDR_All/CloudBaseHeightTotal" /> <netcdf location="VCBHO_npp_d20030125_t084830_e084955_b00015_c20071213022754_den_OPS_SEG.h5" coordValue="0" /> <netcdf location="VCBHO_npp_d20030125_t084955_e085121_b00015_c20071213022754_den_OPS_SEG.h5" coordValue="10" /> </aggregation> </netcdf> Ticket Details =================== Ticket ID: CBY-304423 Department: Support netCDF Java Priority: Normal Status: Open