Long-term trends were computed by state partners using the Seasonal Kendall non-parametric technique for annual data collected from 1999-2013. Highly significant trends are indicated with triangles and possible trends are show with colored circles. Surface total nitrogen concentrations are decreasing/improving significantly at 41 stations, possibly decreasing at 16 stations, increasing/degrading significantly at 1 station, and possibly increasing at 1 station.
Author: Howard Weinberg
Date created: Apr 28 2015 / Download ( 1.44 MB )