An Analysis of the Yearly Changes in Sulfur Concentrations at Various National Parks in the United States for the Period 1980-1996

摘要

An apparent increasing trend in the summertime concentrations of particulate sulfur at Shenandoah (for the time period 1982-1995) and at Great Smoky Mountains (for the time period 1984-95) has been pointed out by Eldred and Cahill~1. White~2 has suggested that these increasing trends may be an analytical artifact resulting from the switch from the SFU measurement system to the Interagency Monitoring of Protected Visual Environments (IMPROVE) measurement system that occurred during the winter of 1987. To obtain a better understanding of the effect of the protocol change, we investigate the changes in the seasonal averages of sulfur concentrations for successive pairs of years for the period 1980-1996 for about 20 national park sites in the United States. For the period 1980-1987 we use sulfur data from the old (SFU) database and for the period 1988-1996 we use IMPROVE database. It does not appear that the protocol change introduced a systematic effect in the sulfur measurements based on the data for the 20 sites we examined.