Ozone production during the field campaign RISFEX 2003 in the Sea of Japan: analysis of sensitivity and behavior basing on an improved indicator

Abstract

Abstract. An improved indicator Φ, based on the present indicator Θ=τOHVOC/τOHNOx, is developed to determine the sensitivity of ozone production to HC and NOx in the field campaign RISFEX 2003 (RIShiri Fall EXperiment 2003) made in September 2003 at Rishiri island (45.07° N, 141.12° E, and 35 m a.s.l.) in the sea of Japan. The indicator, defined as a ratio of kHC+OH[HC] to kNOx+OH[NOx], has a close correlation with the relative sensitivity (dlnP(O3)/dln[NO] and P(O3)/dln[HC]) which can explicitly give the sensitivity of P(O3) to NO and HC. According to the indicator, four distinctive regimes were obtained in which modeled P(O3) behaviors differently with HC and NOx. At Φ<1, P(O3) is located in Regime I and is greatly sensitive to both HC with a positive correlation and NOx with a negative one. In Regime II (1<Φ<7±3), P(O3) is more sensitive to HC than NOx, but has a similar relationship to HC and NOx. P(O3) is both positively sensitive to HC and NOx in Regime III (7±3