1 Descriptive Columbia River estuary and plume II EBS566: Estuary and Ocean Systems II – Lecture 6, Winter 2010 Instructors: T. Peterson, M. Haygood, A. Baptista Division of Environmental and Biomolecular Systems, Oregon Health & Science University
Jan 03, 2016
1 Descriptive Columbia River estuary and plume II
EBS566: Estuary and Ocean Systems II – Lecture 6, Winter 2010Instructors: T. Peterson, M. Haygood, A. Baptista
Division of Environmental and Biomolecular Systems, Oregon Health & Science University
2 Plume regionsSum
mary
by D
avid
Jay o
f re
searc
h b
y A
. H
orn
er-
Devin
e e
t al.
3 Salinity intrusion
am169
Salin
ity (
psu
)Tid
e r
an
ge (
m)
Q (
m3/s
)
4 Biology in context?Oceanic diatoms
Myrionecta rubra
Freshwater diatoms
Riverine phytoplankton: washed down river, lyse in saline water
Myrionecta rubra: develops blooms within the estuary, mobile
Oceanic diatoms: washed into the estuary, generally tolerant of low salinity water
Slide by Charles Seaton
5 Internal waves
A SAR image taken at 01:56:27 GMT, July 8, 2007 showing the surface roughness as a manifestation of IWs
in the Columbia River estuary
Spatial coverage of the radar from the bridge (right) to the river mouth (left) (background courtesy of Google Earth). The red rectangle shows the approximate location of the internal waves. Middle: Photo of the internal waves taken from the
deck of the R/V Pt. Sur at 1600 PDT on September 8, 2009 (courtesy of Craig McNeil). Bottom: image produced from radar data showing the internal waves at 1740 PDT on the same day. The intensity [dB (100V)2] is related to internal wave
amplitude while the spacing indicates wavelength.
6 Salinity intrusion length
(a) Data collected by David Jay on LMER and NOAA cruises
(b) Salinity in psu at an upstream station (data in red, model in black, blue and magenta)
Ch
aw
la,
Jay,
Bap
tista
, W
ilkin
an
d S
eato
n,
CS
R 2
00
8
Predicable
(with somechallenges) 6.8
Aug 26,2004
27 28 29 30 31 Sep 1 20.0
7 Salinity intrusion length
ResponsiveSIL has a clear response to river discharge …
8 Salinity intrusion length
River discharge, Q (m3/s)
SIL
(K
m)
SIL2psu ≈ 5.949Q-0.288 r2=0.823
Based
on
DB
16
Responsive… relatively easy to characterize (“noise” is useful to characterize other
influences)
9 Freshwater diatoms?
Slide by Charles Seaton
10 Oceanic and freshwater diatoms?
Oceanic diatoms
Freshwater diatoms
Slide by Charles Seaton
11 Myrionecta rubra?
Slide by Charles Seaton
12 What are internal waves
Internal waves are gravity waves that oscillate within, rather than on the surface of, a water body in association with a stratified fluid in motion
Slide by Jiayi Pan
13
CRE bottom topography is a key factor for generation of internal waves
U
Internal waves
Lee wave is the generation mechanism
Flood tide current interacts with the bottom topography to generate internal waves
25 m
2 km
How are estuarine internal waves generated in the CR?
Slide by Jiayi Pan
14 Internal waves in Columbia River estuary (CRE)
Internal waves can cause vertical
velocity shear, which can
intensify vertical mixing process
Through vertical mixing in the North Channel, internal waves may be quite important for the ecology of the Columbia River Estuary (CRE).
In particular, internal waves may substantially modulate ocean influences, which are felt predominantly through the North Channel
Not a representation of the CR
Why are estuarine internal waves important in the CR?
Slide by Jiayi Pan
15
Internal waves
Why do we see surface signatures of internal waves?
Slide by Jiayi Pan
16
am12 ADCP U velocity
Internal waves
After removing tidal signals U velocity
Internal waves
Internal waves in Columbia River estuary (CRE)
horizontal Velocity (east-
west)Tides dominate
Tidal Residual horizontal velocity
am12 ADCP U velocity ( Saturn 01 Location)
Can we see internal waves in fixed station records ?
Slide by Jiayi Pan
17
Number of Internal waves 107
Mean wavelength 92.0 (m)
Median 84.3 (m)
Standard Deviation 29.5 (m)
Wavelength Range 157.5 (m)
Minimum wavelength 39.7 (m)
Maximum wavelength 197.2 (m)
The statistics of CRE internal waves from 10 SAR images showing internal waves
Wavelength distribution
Statistical Results of the wavelength
There are 107 waves in these images
Characteristics of internal waves in the CR
Slide by Jiayi Pan
18
SAR image Date and Time (UTC)
(showing Internal waves)
TideTime after LW
(hrs)
Tidal amplitude
(m)
River outflow
Beaver (m3/s)
2005-03-03 01:57:00 early ebb 7.3 1.26 3, 964
2005-06-14 01:53:07 early ebb 7.2 1.59 5, 975
2006-07-03 01:52:30 early ebb 7.2 1.57 5, 777
2006-07-20 01:56:40 flood 5.1 1.58 5, 352
2007-05-11 01:52:20 flood 5.4 1.66 8, 976
2007-08-07 14:35:52 flood 5.3 1.34 4, 390
2007-08-08 01:56:27 flood 5.3 1.33 4, 276
2007-09-07 14:31:42 flood 3.0 1.78 3, 313
2008-07-14 19:05:23 early ebb 7.0 1.55 N/A
2008-08-18 19:05:21 flood 3.8 2.19 N/A
Internal waves in Columbia River estuary (CRE) Characteristics of internal waves in the CR
Slide by Jiayi Pan
19
t (hours)
S
x=31 x=31.5 x=32 x=32.5
x=33 x=33.5 x=34 x=34.5
x=36.5
x=38.5
x=36x=35.5x=35
x=37 x=37.5 x=38
Early modeling
Credit: Joseph Zhang