slide1
Download
Skip this Video
Download Presentation
Observations of Storms off the West Coast in 2012 from Seafloor Data

Loading in 2 Seconds...

play fullscreen
1 / 64

Observations of Storms off the West Coast in 2012 from Seafloor Data - PowerPoint PPT Presentation


  • 86 Views
  • Uploaded on

Observations of Storms off the West Coast in 2012 from Seafloor Data David Atkinson, UVic Dept. of Geography Steve Mihaly, ONC Dilumie Abeysirigunawardena, ONC Martin Heesemann, ONC 2013 CSAS State of Ocean Workshop February 20, 2013. Series of storm events, Jan 19 – 26, 2012:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Observations of Storms off the West Coast in 2012 from Seafloor Data' - winter-wise


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1
Observations of Storms off the West Coast in 2012 from Seafloor Data
    • David Atkinson, UVic Dept. of Geography
    • Steve Mihaly, ONC
    • Dilumie Abeysirigunawardena, ONC
    • Martin Heesemann, ONC
    • 2013 CSAS State of Ocean Workshop
    • February 20, 2013
slide2
Series of storm events, Jan 19 – 26, 2012:
  • Synoptic overview
  • La Perouse traces
  • ONC Folger Passage (Deep) data:
    • surface waves
      • Start with annual variance and comparison, 2011 vs 2012
        • BPR power spectra trace, late summer period
      • spring period close-up
      • storm period close-up
    • ADCP currents
      • storm event response
    • oxygen
      • storm event response
slide3
Series of storm events, Jan 19 – 26, 2012:
  • Synoptic overview.
  • - point to note: potential for different wave source regions during these events
slide4
January 19 2012 00Z
  • Typical progression:
  • - “parent” system moves off jet
  • into GoA
  • Dynamically linked systems
  • generated, moved towards
  • coast and to NE
  • -Support from aloft =
  • rapid increases in strength

M

slide5
January 19 2012 06Z
  • La Perouse Bank buoy
  • Direction
  • Wspd,Hs

M

6,4

slide35
Max sustained wind ~23m/s

(gust 30m/s)

Wave height peaks >8m

Note direction shifts

slide40
Annual: 2011

log

More energetic,

more variable

winter season

Less energetic/variable

summer season

slide41
Annual: 2011

log

February – activity appeared to be winding down

- Kicked back in for an active March

slide43
Annual: 2012

Similar in general form to 2011 – winter active, summer quieter

log

slide44
Annual: 2012

Timings – 2011 winter ended fairly suddenly; 2012 dragged out

log

slide45
Annual: 2012

Timings – both years – late July/August very quiet, September sees increasing activity

log

July/Aug.

Sept.

slide46
First three weeks of September 2012 locally were (very) storm free

Observed energy can not be local.

slide47
Use a running spectral power plot of Folger BPR data to assess wave dispersion

- angled tracks between 25s-10s indicate long period waves arriving well before shorter

= wave trains pumped out by distant storms

Relative

power

Wave

Period

Sept 1

2012

Sept 7

2012

Sept 14

2012

Sept 21

2012

slide48
Annual: 2012

Late Jan. Stormy period – most active single week in 2012

log

slide49
Spring: 2011

Closer look at variance traces for stormy period

log

spring

JAN 01

FEB 01

MAR 01

slide50
Spring: 2011

log

spring

  • Note pattern – waves often exhibit rapid onset, slow decline
  • Cordillera blocks eastern progression of storms
  • move in fast, but stall and die slowly

JAN 01

FEB 01

MAR 01

slide51
Spring: 2011

log

spring

  • Note pattern – waves often exhibit rapid onset, slow decline
  • Cordillera blocks eastern progression of storms
  • move in fast, but stall and die slowly

JAN 01

FEB 01

MAR 01

slide52
Spring: 2011

log

spring

Can also observe fairly regular synoptic timing

3 – 7 days between events in mid-latitudes at this time of year

JAN 01

FEB 01

MAR 01

slide53
Spring: 2012

Similar general pattern but a higher level of activity persisted

- no February slow-down as in 2012

log

spring

Storm period

JAN 01

FEB 01

MAR 01

slide54
Stormy period: Jan 19-27, 2012

Three peaks in local activity, two major (22-23rd and 26th)

log

storms

JAN 18

JAN 21

JAN 24

slide56
Stormy period: Jan 19-27, 2012

ADCP current vector data, daily averages, filtered

North

South

East

West

slide57
Stormy period: Jan 19-27, 2012

Direction maintained,

Speed dropped off

ADCP current vector data, daily averages, filtered

North

South

Rapid wind shift

Bottom return

current

East

West

slide58
Stormy period: Jan 19-27, 2012

ADCP current vector data, daily averages, filtered

Upper ~40m

entrained during

these events

North

South

Possible Barkley

Sound outflow?

East

West

slide61
Stormy period: Jan 19-27, 2012

Oxygen data at 94m compared with ADCP vector currents

slide62
Stormy period: Jan 19-27, 2012

Presumably return flow at depth draws from oxygenated upper flow

Oxygen data at 94m compared with ADCP vector currents

Upwelling?

(SE flow)

slide63
Summary

- 2012 – surface forcing from Folger BPR:

- more active and longer winter/spring

- quiet mid-July/Aug,

- Sept showed activity due to distant storms

- Strong storm period in late Jan

- Folger data show in general

- very high resolution overview of wave activity

- spectral tracks great for ID storm distance

- depth of entrainment of surface water

- indications of overturning flow due to storm-surge forcing/

interactions with Barkley Sound and bathy

- resulting oxygenation at depth

- short lived upwelling events ?

ad