STABLE ISOTOPE SIMULATIONS USING A REGIONAL STABLE ISOTOPE MODEL COUPLED TO A ZONALLY AVERAGED GLOBAL-MODEL

A global zonally averaged stable isotope model (Fisher, 1990) is reviewed, checked and used to give input to a regional model that uses precipitation along assumed vapour trajectories to predict (delta(O-18) and deuterium excess d in Arctic Canada, NW Greenland, Central Greenland, East Antarctica, Victoria Land (Antarctica) and on the Ross Ice Shelf. Where there is predominantly a single moisture trajectory, the model works well but it does not fit the data in regions like Central Greenland (Crete) that would seem to have no predominant regional moisture path. Cloud supersaturation, seasonal precipitation and the temperature at which clouds shift from water droplets to ice crystals are emphasized. Source ocean delta's are not assumed to be zero.