GISS multi-year radiation flux data GISS lwdn lwdn domain.T62.nc time lon lat area mask giss.lwdn.T62.1996.nc giss.lwdn.T62.1997.nc giss.lwdn.T62.1998.nc giss.lwdn.T62.1999.nc giss.lwdn.T62.2000.nc cp:/ptmp/kauff/tn460_data_multi-year/RADFLX/