1. Massachusetts Bay Physical Processes 2011 compared to 2012
Rocky Geyer
Woods Hole Oceanographic Institution

2. River Discharge, 2011 Wet 68th 73rd 88th 93rd 98th 63rd 38th 93rd
percentile
73rd
88th
93rd
98th
63rd
percentile
38th
Record
Maximum*
93rd *

3. River Discharge, 2012 Dry 36th 12th 26th 45th 21rd 21st 12th 31th
percentile
12th
26th
45th
21rd
percentile
21st
12th
31th

5. salinity
Wow!

6. NERACOOS A
Near-field

7. 2011 was wet all year
BIG discharge event in 2010

8. water temperature Upwelling event Mixing event
Record near-bottom water temperature– end of august Why?

9. 2011 Late spring winds and water temperature
Strong upwelling

10. 2012 late spring winds and water temperature
NE wind mixing event
surface
20 m
50 m

11. dissolved oxygen

12. 2011 fall winds and water temperature
Irene
Peak stress same as Irene!

13. 2012 fall winds and water temperature
Hurricane
Sandy

14. Generally warmer deep
water means lower DO

15. Near-bottom Dissolved Oxygen Regression Model
Dopredicted = - A T - B S

16. NERACOOS A East-West current at 50 m—
Does it influence DO?
Toward offshore 10
7.5 5
From offshore

17. summary Precipitation affects river flow, which affects salinity
2011 was wet, and 2012 was dry
Winter temperature sets initial deep-water temperature
2012 had a warm winter, leading to warm bottom water
Upwelling cools surface water and downwelling warms bottom water
Dissolved oxygen co-varies with temperature and salinity
warmer temperatures cause lower DO
higher salinities cause lower DO (different from other systems)
DO is a “regional” variable
strong correlation between NERACOOS and near-field
Bottom DO decreases steadily during the stratified period
Fall wind mixing relieves near-bottom low DO