Abstract

Calculating Nitrogen Flux in the San Bernardino Mountains, California
Track: Environmental Management
Authors: Robert Johnson, Andrzej Bytnerowicz

A method is described that calculates total nitrogen flux (surface deposition and stomatal uptake) for the period 2002 through 2006 in the San Bernardino Mountains of southern California. Results are based on periodic gas concentration measurements, MODIS leaf area index data, and vegetative cover types with respective uptake and deposition velocities. ArcGIS functionality provides for prediction of gas concentration values and their correlation with changing vegetation traits over time, for structuring results in tabular form, and for display of findings. This is accomplished through use of feature class intersection, relational database development, and Python scripting to calculate weighted average values from temporally overlapping but offset periods. These data quantify the distribution of flux and augment environmental studies (e.g. critical loads) that provide guidance in management and planning. Methods are presented that correlate fixed empirical measure values with periodically changing remotely sensed and directly measured data within a fixed geographic extent.