Ecological Archives A020-015-A5

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

Appendix E. Uncertainty assessment for groundwater input (GW).

(E.1)

where was the mean precipitation, ET was the mean evapotranspiration, Aw was the groundwater recharge area, was the mean of measured groundwater DIN, DON, PN, and DIP concentrations, and A was the embayment area. Table E1 contains the parameter values, SE, and degrees of freedom for the values on the right side of Eq. E.1.

and associated SE and df were calculated as described in Appendix C. ET was calculated as the mean of minimum and maximum values of ET from southeastern coastal watersheds reported in the literature. SEET was calculated from Eq. 2. As minimum and maximum values were used to estimate the SE, its df approach infinity and were arbitrarily set to 1000. Aw was calculated as the mean of the minimum and maximum watershed area with SE calculated from Eq. 2. Similar to the df for ET, df for Aw approach infinity and were arbitrarily set to 1000. was calculated by Eq. 2 with df = n–1. Calculations of A and the SE and df for A are described in Appendix A.

The SEGW and dfGW were calculated from Eqs. 3 and 7, respectively, based on the GW formulation (Eq. E.1) where:

(E.2)

(E.3)

 

TABLE E1. Parameter values used in groundwater (GW) input calculations. was the mean precipitation, ET was the mean evapotranspiration, Aw was the groundwater recharge area, were the mean groundwater nutrient concentrations, and A was the embayment area. SE and df were the standard error and degrees of freedom, respectively.

Parameter

Constituent

Value

SE

df

(m/y)

1.44

0.02

1.0

ET (m/y)

1.15

0.15

1000

Aw (m2)

14434

3042

1000

(mmoles/m3)

20.9

7.9

13.0

 

73.7

8.0

8.0

 

0.9

0.5

13.0

A (m2)

9841

27.7

799


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