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K thompson may 2014

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These are the slides from our May 23, 2014 Friday Forum workshop entitled 'Predicting and projecting the frequency of extreme marine events on time scales of days to decades with a focus on coastal flooding' led by Dalhousie University Professor Keith Thompson. The marine environment presents humankind with great economic opportunity but also major risks. It is a dangerous place to extract resources, and a particularly challenging environment for transportation, construction and human development. Our relationship with the marine environment is evolving due to climate change (e.g., global sea level rise, reduced pack ice in the Northwest Passage) and also shifts in economic and societal use (e.g., deep ocean drilling, marine recreational activities). In 2012 a new national network was established to bring together researchers and partners in a multi-sectoral partnership in order to improve Canada’s capabilities in Marine Environmental Observation, Prediction and Response (MEOPAR). In this talk Keith first provided an overview of this new network and then described some of its research, focusing mostly on coastal flooding. He then described how MEOPAR is making extended-range predictions of east coast storm surges, and the probability of coastal flooding, with lead times of hours to about 10 days. He also described a new statistically-based method for estimating the probability of coastal flooding over the next century, taking into account uncertainty in projections of sea level rise and storminess. Keith Thompson is a Professor at Dalhousie University with a joint appointment in the Department of Oceanography and the Department of Mathematics and Statistics. He holds a Canada Research Chair in Marine Prediction and Environmental Statistics. His research interests include ocean and shelf modelling, data assimilation, sea level variability, the analysis of extremes. New interests include the Madden Julian Oscillation and the Kuroshio Extension current system. He is presently a theme lead for the Marine Environmental Observation Prediction and Response (MEOPAR) network, a large national network established recently to help Canada respond more effectively to marine emergencies and change.
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Keith Thompson Natacha Bernier Dalhousie University Environment Canada
Transcript
Page 1: K thompson may 2014

   Keith  Thompson          Natacha  Bernier  Dalhousie  University                      Environment  Canada  

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Overview  of  Talk  

 Overview  of  MEOPAR,  a  new  naDonal  network  

  PredicDng  storm  surges  with  lead  Dmes  up  to  10  days  

  ProjecDng  flood  probabiliDes  over  coming  decades  

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MEOPAR  in  a  Nutshell  

  New  network  of  centers  of  excellence   Marine  Environmental  ObservaDon  PredicDon  and  Response    Reducing  vulnerability  to  marine  hazards  and  emergencies    Established  in  2013,  headquartered  at  Dalhousie    $25M  over  5  years  from  NCE  program     May  be  renewed  twice    Involves  50  researchers  from  12  universiDes    Partners  include  EC,  DFO,  DND,  DRDC,  Lloyds  Register,  ICLR,  ...    

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Dr.  Harold  Ritchie,  Environment  Canada/  Dalhousie  University  

A  relocatable  atmosphere-­‐wave-­‐ocean  forecast  system  that  can  be  set  up  within  hours  of  a  marine  emergency.    

Provide  forecasts  (hours  to  days)  of  physical  properties  of  ocean  and  atmosphere  to  help  guide  response  to  an  emergency.  System  to  be  transferred  to  Environment  Canada  for  operational  use.  

A  Relocatable  Atmosphere-­‐Ocean  Prediction  System  Who:  

What:  

Impact:  

Photo  credit:  ArcticNet  

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Dr.  Jinyu  Sheng,  Dalhousie  Dr.  Susan  Allen,  UBC  

Build  an  integrated  observation  and  prediction  system  for  Halifax  Harbour  and  Strait  of  Georgia.  

Real-­‐time  forecasts  of  sea  level,  waves,  currents,  bio-­‐geochemical  properties  for  ports,  municipalities,  and  the  oil  and  gas  sector.  

Building  Network  of  Fixed  Coastal  Observing  &  Forecast  Systems  

Who:  

What:  

Impact:  

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Dr.  Dany  Dumont,  UQAR  

Improve  surface  drift  forecasts  in  seasonally  ice-­‐infested  seas.  Some  buoys  deployed  by  the  UQAR  ice  canoe  team.  

Respond  to  emergencies  along  Canadian  coasts  e.g.,  a  person  or  oil  patch.  Time  is  key  in  ice-­‐infested  water.  

Improving  Surface  Drift  Forecasts    

Who:  

What:  

Impact:  

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Dr.  Andrea  Scott,    University  of  Waterloo  

Method  to  use  radar  (SAR)  satellite  images  to  improve  the  monitoring  of  sea  ice.  

Accurate  information  about  sea  ice  conditions  is  critical  for  weather  forecasting  and  safe  navigation  in  ice-­‐covered  regions.  

Improving  Sea  Ice  Forecasts  

Who:  

What:  

Impact:  

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Dr.  Gregory  Flato,    Environment  Canada/  Uvic  

Develop  ways  to  assess  and  visualize  changes  in  the  marine  environment  and  the  associated  risks  on  climate  time  scales.  

The  fishing  industry  and  coastal  communities  could.  e.g.,    use  risk  maps  to  manage  their  exposure  to  extreme  weather  events.  

Climate  Change  and  Extreme  Events  in  the  Marine  Environment  

Who:  

What:  

Impact:  

Photo:  CC  Sam  Beebe  

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Dr. Katja Fennel, Dalhousie University

Develop biogeochmical, predictive models of the ocean and make climate projections.

Assist planning by, e.g., fishing industry, oil and gas industry, and coastal communities.

Biogeochemical  Projections  Under  a  Changing  Climate  

Who:  

What:  

Impact:  

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Photo  credit:  ArcticNet  

Dr.  David  Atkinson,  UVic  

Assess  how  large-­‐scale  weather  patterns  adversely  impact  marine  transport  and    industrial  activity  in  eastern  Beaufort  Sea.  

Ensure  marine  operators,  coastal  communities  and  emergency  response  operators  have  access  to  weather  forecast  information  to  help  plan  operations.  

User-­‐Driven  Monitoring  of  Adverse  Marine  and  Weather  States  in  the  Eastern  Beaufort  Sea  

Who:  

What:  

Impact:  

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MEOPeople  

Training  highly  qualified  personnel  is  one  of  MEOPAR’s  most  important  objectives.  

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INFORMED  SOCIETY  

•  More  people  using  research  results  

•  Information  about  the  ocean  readily  available  

COORDINATED  CANADIAN  APPROACH  

•  Bringing  together  researchers,  industry,  and  NGOs  

•  Better  techniques  &  policies  

•  Hazard  management  

TRAINED  PEOPLE  

•  Ocean  skills  •  Student  mentoring  

MEOPAR’S  Outcomes  

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PredicDng  Storm  Surges    With  Lead  Times  up  to  10  Days  

Storm  surges  are  an  ever  present  danger  in  eastern  Canada  

Home  damaged  by  the    storm  surge  of  December,  2010  Sainte  Luce,  Quebec  

hZp://joansullivanphotography.com/STILLS/Climate-­‐change  

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Flooding  is  Caused  by  Tide  and  Surge  

η =ηT +ηS

Halifax  February  1967  

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ForecasDng  Storm  Surges  

Surge  models  are  usually  based  on  two  simple  physical  principles  expressed  by  the  following  equaDons:  

DiscreDze  on  a  grid  with  realisDc  coastlines  and  water  depths.  Integrate  through  Dme  with  forecast  wind  to  forecast  surge.    

Du

Dt= − f ×u − g∇(η−ηp )+

τH−

cd u u

H∂η∂t

+∇ • (uH ) = 0

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Our  Surge  Model  and  Domain  

•   Model  is  2D,  based  on  POM  

•   Shelf  and  deep  water,          Labrador  to  Gulf  of  Maine  

•   Driven  by  10  day  forecast  winds      and  air  pressure  

•   DeterminisDc  (1/30°)  

•   Ensemble  (1/12°)  

•   1  March  2013  to  31  March,  2014  

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Typical  DeterminisDc    Forecasts  

 Rimouski    ObservaDons  in  black  

3  day  forecasts  

5  day  forecasts  

7  day  forecasts  

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How  Good  are  the  DeterminisDc  Forecasts?  

γ 2 =var(ηobs −ηmod )

var(ηobs )=

error

obs

For  each  of  the  22  Dde  gauges  calculate  

γ 2

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Allowing  for  Uncertainty  in  Wind  Forecasts  

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Visualizing  Ensemble  Surge  Forecasts  

5d  forecast  for  22  March  2013  

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5  Day  Forecasts  of  Total  Water  Level  

η =ηT +ηS

Sea  Level  (m)  

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ProjecDng  Flood  ProbabiliDes    Over  Coming  Decades  

Such  informaDon  is  needed  for  sensible  adaptaDon  strategies.  

Problem  is  conceptually  similar  to  predicDng  total  water  levels  10  days  into  future.  

Let’s  start  by  looking  at  some  observaDons  from  the  long  Halifax  sea  level  record.  

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Annual  Means  and  Maxima  for  Halifax  

Halifax  1920-­‐2001  

Offset  due  to  Ddes  

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Annual  Maxima  About  Annual  Means  

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Probability  of  Flooding  Today  

Halifax  return  level  about  mean  (m)  

+0.3m  

Return  period  (years)  

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100y  ProjecDons  of  Flood  ProbabiliDes  

Simplest  approach:  Assume  mean  sea  level  will  increase  by  fixed  amount  and  just  raise  return  levels.  “DeterminisDc”.  

But  sea  level  increase  over  next  century  is  highly  uncertain  (e.g.,  uncertain  emission  scenarios,  model  errors).  

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Projected  Sea  Level  Rise  Over  Next  Century    

IPCC,  2013:    Summary  for  Policymakers.    Figure  SPM.9  

“medium  confidence”  

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ProjecDng  Probability  of  Total  Water  Level  

Write  annual  maximum  as  sum  of  annual  mean  and  a  deviaDon:  

Assume  pdfs  for  these  two  components  are  of  form:  

The  pdf  of  annual  maximum  is  convoluDon  of  these  two  pdfs.  

η = ηA + ηD

p(ηA ) = w1δ(ηA −ηS1)+ w2δ(ηA −ηS2 )+ ...

p(ηD ) = φG (ηD )

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Idealized  Example  Assume  there  are  only  possible  SLR  scenarios:  

S1:  Sea  level  rises  at  0.3m  per  century                          P(S1)=0.8    S2:  Sea  level  rises  at  1.0m  per  century                          P(S2)=0.2    

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Impact  of  Uncertainty  on  Return  Levels  

Return  level  for  

Idealized  Example  

(m)  

Return  period  (years)  

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Average  Dme  between  floods  (years)  

What  Should  Halifax  Expect  Today?  

1.9m  

300y  

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Impact  of  1.9m  on  Downtown  Halifax  

Charles  et  al.,  2011  

Expect  one  every  300y  if  present  condiDons  prevail  

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Flood  level  (m)  

What  Should  Halifax  Expect  in  2100?  

1.9m  

4y  

Probability  of  exceeding  high  flood  levels  is  determined  by  more  extreme,  but  less  likely,  scenarios  

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  Trend  toward  probabilisDc  predicDons  and  projecDons  of  sea  level,  based  on  ensembles  and  expert  knowledge.    

 Uncertainty  is  not  a  sign  of  bad  models  or  science.    

  Surge  predicDons  are  improving  (known  unknowns).  Expect  rapid  improvements  over  next  five  years.  

  Climate  projecDons  more  complex  (unknown  unknowns?)  BeZer  understanding  may  lead  to  greater  uncertainty.  

 Work  presented  here  illustrates  a  small  part  of  the  research  being  conducted  by  MEOPAR.      

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Impact  of  Uncertainty  on  Probability,    and  Number,  of  Floods  with  Time  

Critical  level  Is  2  m  


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