UPTAKE OF NOY ON WAVE-CLOUD ICE PARTICLES

In a flight through a wave cloud during SUCCESS on 2 May 1996, simulta neous forward- and aft-facing NOy inlets were used to infer the amount of condensed-phase NOy present on ice particles that were up to a few minutes old. Condensed-phase amounts were 25-75 pptv, or 10-20% of ga s-phase NOy. Given the rapid HNO3 uptake on ice observed in the labora tory, a model calculation implies that virtually all of the gas-phase HNO3 will be depleted in the first 1-2 minutes after the appearance of ice. Thus the NOy observations are consistent with the laboratory res ults only if the ambient HNO3/NOy ratio is 10-20%.