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Update on the Ecological Model: Box Model Version. Mark Brush ( VIMS) CHRP October 8, 2009. Officer Box Model. Current Activities. Expanding from 2001 – 2008 Improved salinity functions around the bay: NuShuttle data Alternate S functions: - Cosine functions
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Update on the Ecological Model:Box Model Version Mark Brush (VIMS) CHRP October 8, 2009
Current Activities • Expanding from 2001 – 2008 • Improved salinity functions around the bay: NuShuttle data • Alternate S functions: • - Cosine functions • - Insomniacs + NuShuttle • - Supplement with buoy data when available
Relating Model Daily Average Results to Management Criteria Mark Brush (VIMS) CHRP October 8, 2009
One potential problem re: management use of the model: • RI O2 criteria focus on instantaneous values • Our eco model simulates daily mean O2 • Models can simulate diel O2 variations, but …
Rhode Island DO criteria: Surface Waters (and waters without a pycnocline): “Waters with a DO concentration above an instantaneous value of 4.8 mg/l shall be considered protective of Aquatic Life Uses.” Bottom Waters (waters with a pycnocline): As above, plus … “When instantaneous DO values fall below 4.8 mg/l, the waters shall not be: 1. Less than 2.9 mg/l for more than 24 consecutive hours during the recruitment season; nor 2. Less than 1.4 mg/l for more than 1 hour more than twice during the recruitment season; nor 3. Shall they exceed the cumulative DO exposure presented in Table 3.A.”
Concept for GEMBox / GEM-OBM: Use buoy O2 data to look for relationships between: • daily mean DO • instantaneous minimum DO • time with DO below 2.9 mg/l • time with DO below 1.4 mg/l 2.9 DO t2.9 2.9 1.4 mean DO Inst. min t1.4 ? NCP CR DO
Test sites: • North Prudence • Conimicut Point • Bullocks Reach • Greenwich Bay • 2003, 2005-07
Test sites: • North Prudence • 2003 SURFACE BOTTOM
Test sites: • Conimicut Point • 2003 SURFACE BOTTOM
Test sites: • Bullocks Reach • 2003 SURFACE BOTTOM
Test sites: • Greenwich Bay • 2003 SURFACE Need a change-point regression? BOTTOM
All years together … 2003, 2005-07
Test sites: • North Prudence • 2003, 2005-07 SURFACE BOTTOM
Test sites: • Conimicut Point • 2003, 2005-07 SURFACE BOTTOM
Test sites: • Bullocks Reach • 2003, 2005-07 SURFACE BOTTOM
Test sites: • Greenwich Bay • 2003, 2005-07 SURFACE BOTTOM
Test sites: • All Sites • 2003, 2005-07 SURFACE BOTTOM
Predicting DO Criteria Attainment: • Inst. min. DO and time below DO thresholds appears predictable directly from daily mean DO • Addition of terms for metabolism does not appear to help • Fit is especially good in bottom waters, which is good news • Relationship appears robust across years, and to a lesser degree across sites • PROPOSAL: fit statistical distribution functions by site (years aggregated) with all available buoys to predict criteria attainment/violation from modeled daily mean DO