Ecological Archives A020-015-A3

John C. Lehrter and Just Cebrian. 2010. Uncertainty propagation in an ecosystem nutrient budget. Ecological Applications 20:508–524.

Appendix C. Uncertainty assessment for atmospheric deposition (AtmDep).

AtmDep = ( ) + ( Dry:Wet)

(C.1)

where was the mean annual precipitation, was the mean nutrient concentration (DIN, DON, or DIP), and Dry:Wet was the ratio of dry atmospheric deposition to wet deposition for DIN, DON, and DIP. Table C1 contains the parameter values, SE, and degrees of freedom for the values on the right side of Eq. C.1.

Precipitation was measured continuously over the study period (i.e., every rainfall event was measured) at three locations (Fig. 1). Annual precipitation at a given site is a cumulative measurement. However, the gauge adjacent to the Gongora site was inoperable from 6 February 2004 through 16 March 2004. Therefore, mean precipitation () was calculated from the annual precipitation at the other two locations, was calculated from equation (2), and was calculated as n–1 with n = 2. Mean rainfall nutrient concentrations () were calculated from measured rainfall DIN, DON, and DIP at these same three locations with calculated by equation (2) and df = n–1.

Dry:Wet was the mean of literature values with the SE calculated with Eq. 2 and df equal to n–1, where in this case n was the number of literature values averaged. The SEAtmDep and dfAtmDep were calculated from Eqs. 3 and 7, respectively, based on the AtmDep formulation (Eq. C.1) where

(C.2)

(C.3)

TABLE C1. Parameter values used in atmospheric deposition (AtmDep) calculations. was the mean precipitation. were the mean rainfall concentrations. Dry:Wet was the mean ratio of dry deposition to wet deposition. SE and df were the standard error and degrees of freedom.

Parameter

Constituent

Value

SE

df

(m/y)

1.44

0.02

1.0

(mmoles/m3)

22.1

3.72

66.0

 

17.6

3.76

17.0

 

0.65

0.11

64.0

Dry:Wet (unitless)

DIN

0.57

0.024

2.0

 

DON

0.24

0.018

2.0

 

DIP

4.78

1.66

2.0


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