I want to get actual data (or information as to where I can get the
data) for the ocean currents of the Pacific Ocean on the continental
slope.  Specifically, I am interesed in finding, if possible, data as
to ocean currents at the level of the sea floor and up to about 50
meters above the sea floor on the continental slope in water depths of
about 400 meters.  I believe the main current in this are is called
the California Undercurrent, but not too sure.  Data off of the San
Diego coast is most preferred. Background informatin would be helpful,
but is not enough to answer my question.

Hi oceanmark,

I hope you find the following links just what you are looking for -
pay particular attention to number 2.

1. The California Undercurrent explained:
"Tanner Basin is primarily influenced by the southerly flowing
California Current (Fig. 1) (Reid et al., 1958). The inner edge of the
California Current flows along the outer periphery of the Borderland
(except during spring) and turns toward the coast near San Diego. The
average surface flow in the central portion of the Borderland is the
northerly flowing southern California Countercurrent (Fig. 1). The
northern Channel Islands substantially block this flow, and much of
the current is diverted to the west, where it merges with the
California Current (Lynn and Simpson, 1987). This results in the
formation of a counterclockwise-flowing gyre in the southern
California bight (except during spring). The net flow beneath these
two currents is the northward-flowing California Undercurrent (Lynn
and Simpson, 1987; Reid et al., 1958)."
http://www-odp.tamu.edu/publications/167_SR/chap_07/c7_2.htm

2. Data and figures:
The California Current System
Comparison of Geostrophic Currents,
ADCP Currents and Satellite Altimetry
LCDR David O. Neander, NOAA :
http://www.weather.nps.navy.mil/~psguest/OC3570/CDROM/summer2001/Neander/report.pdf

3. Current Patterns Over the Continental Shelf and Slope
Marlene A. Noble
http://geopubs.wr.usgs.gov/circular/c1198/chapters/067-089_CurrentPatterns.pdf.

4. Seasonal dynamics of the surface circulation in the 
Southern California Current System
Emanuele Di Lorenzo
http://horizon.ucsd.edu/manu/papers/DiLorenzo_2002.pdf.

5. The warming of the California Current System:
Dynamics, thermodynamics and ecosystem implications
Emanuele Di Lorenzo and Arthur J. Miller 
http://horizon.ucsd.edu/manu/papers/DiLorenzo_jpo2003.pdf.

6. U.S. GLOBEC
Global Ocean Ecosystems Dynamics
A Component of the U.S. Global Change Research Program
Eastern Boundary Current Program
Report on Climate Change and the
California Current Ecosystem
http://www.usglobec.org/reports/reports.pdf.files/ebcccs.pdf.

Additional Links:

Southern California Buoy Data:
http://facs.scripps.edu/surf/socal.html

The Coastal Data Information Program (CDIP)
http://cdip.ucsd.edu/

Center for Coastal Studies
University of California, San Diego
http://www-ccs.ucsd.edu/

I hope this helps. If you have any questions or if this doesn't
satisfy your request, please post a clarification request before
rating my answer.

Thank you,
hummer


Search Strategy:
://www.google.ca/search?num=100&hl=en&ie=UTF-8&oe=UTF-8&as_qdr=all&q=ocean+currents+%22Pacific+Ocean%22+%22California+Undercurrent%22&btnG=Google+Search&meta=

Terms Used:
ocean currents 
"Pacific Ocean" 
"California Undercurrent"

---

Request for Answer Clarification by oceanmark-ga on 03 May 2003 23:31 PDT

Reference 2 does technically answer the question, which gives current
data for the depth of water I am interested in, but it does not give
the current velocity near the sea floor at 400 meters or so. 
Reference 2 shows the current at the depth of interest, but it is for
water which is much deeper than 400 meters, I believe. Can any more
data be found for ocean currents near the sea floor off of the San
Diego coast?  Some of the references talk of Calcofi data, but I
cannot find current data for near the sea floor at the calofi site.
However, some of your references clearly show that such data exists. 
You can take another look at this if you like.  However, I do agree
that you answered the question to a sufficient extent.  Thank you for
your excellent effort.

oceanmark-ga

---

Clarification of Answer by hummer-ga on 04 May 2003 07:54 PDT

Hi oceanmark,

Sure, I will be happy to have another look to try and nail this one
down for you. However, we will be out for the day and so I won't be
able to get back to you until Monday at the earliest. In the meantime,
here are a few more links to have a look at.

SAN CLEMENTE IS: 46048: 46048b.328
http://www-ccs.ucsd.edu/zoo/ndbc/html/ndbc_adcp.html

Analysis and Acquisition of Observations of the Circulation
on the California Continental Shelf
University of California, San Diego
Scripps Institution of Oceanography
http://www-ccs.ucsd.edu/research/sbcsmb/qrb/qrb7_3.pdf

You've tried this?
1990-2000 CalCOFI Data Report Index: click on one of the stations on
the map to see the data collected. Unfortunately, I don't see the
current velocity, do you?
http://www.calcofi.org/data/1990s/1990rpts.html

"The California Undercurrent is a strong poleward flow found over the
slope. It has been observed everywhere along the coast where
observations have been made including southern California (Lynn and
Simpson, 1989), off Point Conception and Point Sur (Chelton, 1984;
Chelton et al., 1988; Tisch et al., 1991), Northern California
(Freitag and Halpern, 1981), Oregon (Huyer et al., 1984; Huyer and
Smith, 1985), Washington (Hickey, 1979), and Vancouver Island, British
Columbia (Freeland et al., 1984). The position, strength, and core
velocity of the undercurrent vary from place to place and at different
times of the year, but we typically expect a maximum poleward velocity
of around 30 cm/s between 150 to 300 m depth over the continental
slope in water 500-1000 m deep. The CalCOFI data set, averaged over 23
years (Chelton, 1984) gives some idea of the spatial and temporal
extent of the California Undercurrent off Point Sur (Figure 5). These
observations lead us to expect a well-developed undercurrent will be
found over the Farallones slope. Undercurrent dynamics are poorly
understood, but poleward pressure gradient forces due to the variable
surface wind stress are once again often cited (McCreary, 1987). This
is an area deserving further research."
http://walrus.wr.usgs.gov/reports/ofr92-382/

Talk to you soon,
hummer

---

Clarification of Answer by hummer-ga on 05 May 2003 14:23 PDT

Hi oceanmark,

I'm sorry, but I haven't had any luck in finding the current velocity
near the sea floor at 400 meters off the coast of San Diego. Here are
some more links but none, I'm afraid, are exactly what you are looking
for.

Circulation in the Southern California Bight:
http://seis.natsci.csulb.edu/bperry/scbweb/circulation.htm

Huntington Beach Shoreline: Instrumented moorings at 12 locations
monitored current velocity, temperature, and salinity at many depths
every few minutes for 4 months in the summer/fall of 2001
http://geopubs.wr.usgs.gov/open-file/of03-62/measurement.html

WOCA Current Meter Data: PCM2  California Current:
http://woce.nodc.noaa.gov/woce_v3/wocedata_1/cmdac/welcome.htm

DelMar:
"NSF-funded study of temperature and currents over the narrow southern
California shelf north of San Diego. Moorings deployed June 1978
through March 1979 at 3 sites, with 2 current meters at 15m, 4
instruments at 30m, and 6 instruments at 60m."
http://ccs.ucsd.edu/zoo/

Current Meter Performance in the Surfzone:
http://science.whoi.edu/PVLAB/XTREE/xtree.pdf

Too deep but great figures:
http://data1.gfdl.noaa.gov/WOCE-V3.0/disk1/cmdac/netcdf/pcm2/pcm2.htm

Joint Probability Distribution for Current Velocity Measured at 45 m
on the
Mid-Shelf Point-Sal Mooring from the SBC-SMB Study: Page D-8
http://www.countyofsb.org/energy/documents/projects/tranquillonEIR/App_D.pdf

Oceanography Resources on the Internet
http://www.esdim.noaa.gov/ocean_page.html

Scripps Institution of Oceanography Library
http://scilib.ucsd.edu/sio/

If you can manage it, pay the Department of Oceanography at the
Scripps Institute and the Library a visit and talk to as many people
as you can - someone is bound to be able to help you there!

Take care,
hummer

I thank Hummer for the triple effort put in on this answer.  This
answer will inspire me to ask my next question, which perhaps Hummer
will be able to also answer - how to take the current reading myself. 
Thanks again hummer for a great job.

Oceanmark

Dear Oceanmark,

I'm very happy to hear that you are happy and I'd like to thank you
for your kind words, fine rating and tip. Although frustrating at
times, I enjoyed working on your question, and as you can see, it is
still on my mind.

California Undercurrent
"One of the two narrow, poleward-flowing boundary currents in the
California Current system (the other being the Inshore
Countercurrent). The CU appears as a subsurface maximum of flow
between 100 and 250 m deep over the continental slope and transports
warm, saline equatorial waters. It flows within 150 km of the coast as
opposed to the 850-900 km extent of the southward flowing CC. The flow
seems to be continuous for distances of 400 km or more, and has been
observed at locations ranging from Baja California to Vancouver
Island. Current measurements off Central California indicate
continuous, year-round flow over the upper slope at around 350 m with
an average speed of 7.6 cm s$ ^{-1}$. See Collins et al. (2000)."
http://stommel.tamu.edu/~baum/paleo/ocean/node5.html

As for taking the readings yourself (!), I would be honored to give
you a hand. Just make "For hummer-ga" the subject of your question and
I will find it.

Take care,
Hummer