Long-term monitoring of precipitation chemistry. Insights into environmental changes from Hubbard Brook and the MAP3S/AIRMoN network.
Tom Butler1, Gene E. Likens2, Francoise Vermeylen3, Roger Claybrooke4 and Robert Larson5
The NADP/NTN network began operations in 1978, but a longer record of precipitation chemistry is available from the Hubbard Brook Experimental Forest in NH (started in 1963), some independent monitoring in New York State (1970 and 1971), and the MAP3S network which began in 1976 and evolved into the NADP/AIRMoN network. We use annual data from these long-term records, and other published data, to enhance the precipitation chemistry record previous to the establishment of NADP. We also examine the importance of the entire record from all of these stations and/or networks to show how they resulted in a better understanding of precipitation chemistry, and the implications of this record for promoting policy to improve air quality and reduce atmospheric pollutant loading such as acid rain. Combining the Hubbard Brook record, and the 5 longest operating MAP3S/AIRMoN sites (IL11, NY67, DE02, PA15 and TN00) a mixed model statistical analysis show overall declines in concentrations of H+, SO42- and NO3- from 1981 to 2017 of 85%, 80% and 66%, respectively. Calcium concentration shows a 13% decline and NH4+ shows no change.
1Cary Institute and Cornell University, tjb2@cornell.edu 2University of Connecticut, Storrs CT and the Cary Institute, likensg@caryinstitute.org 3Statistical Consulting Unit, Cornell University, fmv1@cornell.edu 4USGS Central Midwest Water Science Center, Urbana, IL, rclaybrooke@usgs.gov 5NADP Program Office, WSLH, Madison, WI, robert.larson@slh.wisc.edu