Department of Mathematics & Statistics
6316 Coburg Road, PO Box 15000
Halifax, Nova Scotia
Canada B3H 4R2
Telephone: (902) 494-1048
Fax : (902) 494-5130
Office: Chase Building, Room 116
Research Interests My research interests are in
Environmental Modelling and Statistics for the Marine Sciences. They
Statistical Data Assimilation
I have an ongoing research interest in data
assimilation, i.e. combining nonlinear dynamical models with available
observations to produce optimal estimates of the time evolving system
state and model parameters. This involves linking statistical
estimation theory to the problem of fitting dynamical models
(governed by time and space dependent partial differential equations)
to observations. My recent research involves statistical approaches
for the data assimilation problem. These rely on the nonlinear,
nonGaussian state space model and use Monte Carlo based Bayesian computational methods. These ideas have been applied to marine
ecological prediction, considering both the complex dynamical
behaviour of biological models, as well as the high dimensionality
found in practical applications.
Stochastic Marine Ecosystem Modelling
Another research area I have is in the
development of mathematical models for lower trophic levels of marine
ecosystems. Currently, I am considering stochastic versions of such
ecological models for uncertainty qunatification, as well as Bayesian approachs to combining them
with new types of observational data. This work has been
focused on development and application of differential equation based
models of coastal ecosystems to assess environmental effects of
shellfish aquaculture, but also food web models and spatial ecology.
Data Analysis Methods for Marine
Environmental Observations :
I also have a
general interest in the development and application of statistical
analysis techniques for marine environmental data sets, especially
satellite imagery. These have incuded spatial analysis of
spaceborne synthetic aperture radar data for high resolution ocean
winds and waves, and ocean color data for for biogeochemical models.
Studies have also been undertaken into trend detection using monitoring
time series of plankton, as well as looking at analysis of high resolution
marine animal movement data and its link to behaviour.
Recent Students and Post-Docs
- Omar Alghamdi (PhD Statistics): (Fall 2015 - present)
- Maria Reyes (MSc Statistics): Incorporating a Gaussian Process
Emulator within a Particle Filter (Winter 2014 - present)
- Joey Hartling (MSc Statistics): Statistical Software for State Space Models (Fall 2011 - present)
- Justin Slater (BSc Honours). Wavelet Analysis in Theory and
Practice (completed Summer 2014)
- David Fay (MSc Statistics): Time Series Analysis of Paleo-Climate
Data (completed Summer 2014)
- Greg Britten (MSc Biology): Time varying population dynamics of
marine fish stocks (completed Fall 2014)
- Celene Burnell (BSc Honours): Quantifying fish behaviour from
accelerometer data (completed Winter 2014)
- Cashelle Fahey (BSc Honours): Computational Bayesian approaches
for estimating time series parameters (completed Winter 2014)
- Miranda McMillian (BSc Honours): Using Copulas for modelling dependence with application to marine benthic data (completed Winter 2013)
- Paul Mattern (PhD Statistics): Parameter estimation for large scale ocean biogeochemical models (completed Summer 2012)
- Sarah Ambrose (BSc Honours): Robustifying the Kalman Filter (completed Winter 2012)
- Jessica Wong (MSc Statistics): Particle MCMC for estimating parameters in a dynamic predator prey model (Completed Spring 2012)
- Jon Briggs (PhD Statistics, Univ Auckland, New Zealand): Data Assimilation with Sequential Monte Carlo (completed Fall 2011)
- Greg Britten (BSc Honours): Modeling ecosystem stability and ecological interactions (completed Winter 2011)
- Joe Boutilier (BSc Honours) Sensitivity analysis of the parameters in a modified random walk model for marine animal movement (completed Spring 2009)
- Scott Wile (MSc Statistics): Parameter estimation and model selection for nonlinear time series (completed Fall 2008)
- Rick Danielson (Post-Doctoral Fellow): Estimation of high resolution marine winds fields from RADARSAT synthetic aperture radar (2004-2008)
- Paul Mattern (MSc, Univ Lubeck, Germany): Ensemble based data assimilation for a physical-biological model near Bermuda (completed Spring 2008)
- Elizabete Almeida (MSc Statistics): Analysis of ocean biogeochemical time series using a cyclical state space model (completed Spring 2008)
- Maud Guarracino (Post-Doctoral Fellow): Coupled biological-physical modelling of lower trophic level coastal ecosystems (2004-2008)
- Jill Falkenberg (BSc Honours): Time dependent value at risk models for financial portfolios using a Kalman filter (completed Spring 2007)
- Laura MacKenzie (MSc Statistics): Nonlinear time series analysis using a Monte Carlo Smooother (completed summer 2006)
Sam Stewart (BSc Honours): Spatial analysis of Radarsat synthetic aperture ocean imagery for wind estimation (completed winter 2006)
Chris Jones (MSc Statistics): State space models for bio-optical oceanic time series (completed winter 2006).
- Sean Smith (MSc Statistics): Options pricing and stochastic
volatility models for financial time series using particle filters (completed Winter 2006).
- Talia Beech (MSc Statistics): Statistical tools for selection of
Marine Protected Areas based on satellite imagery (completed Winter 2006)
- Cathy French (BSc Honours): Nonlinear time series models for temperature prediction (completed winter 2005)
Refereed Journal Publications:
Britten G, Dowd M, Worm B. 2016. Recognizing Ecological Income
Equality in the Ocean. Proceedings of the National Academy of the
Sciences (Letter) doi: 10.1073/pnas.1600793113
Britten G, Dowd M, Worm B. 2016. Changing Recruitment Capacity in
Global Fish Stocks. Proceedings of the National Academy of the
Turk D, Yates KK, Vega-Rodriguez M, Toro-Farmer G,L’Esperance C, Melo
N, Ramsewak D, Dowd M, Estrada SC, Muller-Karger FE, Herwitz SR,
McGillis WR. 2015. Community metabolism in shallow coral reef and
seagrass ecosystems, lower Florida Keys. Marine Ecology Progress Series 538:35-52.
- Wong MC, Dowd M. 2015. Patterns of macroinfaunal taxonomic and
functional diversity differ across seagrass habitats: a case study
in Atlantic Canada. Estuaries and Coasts 38(6):2323-2336
- Joy R, Dowd M, Battaile B, Lestenkoff P, Sterling J, Trites AW,
Routledge R. 2015. Linking northern fur seal dive behaviour to
environmental variables in the eastern Bering Sea. EcoSphere
6(5):75. DOI 10.1890/ES14-00314.1
- Britten G, Dowd M, Minto C, Ferretti F, Boero F, Lotze
H. 2014. Predator decline leads to decreased stability in a coastal
fish community. Ecology Letters 17(12):1518-1525.
- Mattern JP, Fennel K, Dowd M. 2014. Periodic time-dependent
parameters improve forecasting abilities of biological ocean
models. Geophysical Research Letters 41(19):6848- 6854.
- Dowd M, Jones E, Parslow J. 2014. A Statistical Overview and
Perspectives on Data Assimilation for Marine Biogeochemical
Models. Environmetrics, 25(4):203–213
- Boyce D, Dowd M, Lewis, M, Worm B. 2014. Estimating global
chlorophyll changes over the past century. Progress in Oceanography, 122: 163-173
- Wong M, Dowd M. 2014. Role of invasive green crabs in the food web of an intertidal sand flat determined from field observations and a dynamic simulation model. Estuaries and Coasts 37(4): 1004-1016.
- Dowd M, Grant J, Lu L. 2014. Predictive Modeling Of Marine Benthic Macrofauna And Its Use To Inform Spatial Monitoring Design. Ecological Applications, 24(4): 862-876
- Wong M, Bravo M, Dowd M. 2013. Ecological dynamics of Zostera
marina (eelgrass) in three adjacent bays in Atlantic Canada.
Botanica Marina 56 (5-6): 413-424
- Mattern JP, Dowd M., Fennel K. 2013. Particle Filter-based Data
Assimilation for a 3-dimensional Biological Ocean Model and Satellite
Observations. Journal of Geophysical Research: Oceans,
- Mattern JP, Fennel K, Dowd M. 2013. Sensitivity and uncertainty analysis of model hypoxia estimates for the Texas-Louisiana shelf. Journal of Geophysical Research: Oceans, 118:1–17, DOI: 10.1002/jgrc.20130.
- Briggs J, Dowd M, Meyer R. 2013. Data assimilation for Large Scale Spatio-Temporal Systems using a Location Particle Smoother. Environmetrics. DOI: 10.1002/env.2184.
- Mattern JP, Fennel K, Dowd M. 2012. Estimating time-dependent parameters for a biological ocean model using an emulator approach. Journal of Marine Systems. 96-97, 32-48.
- Guarracino M, Dowd M, Sheng J, Cullen JJ. 2011. Development of a coupled biological-physical model for prediction in a coastal inlet. Continental Shelf Research. 31(16): 1713-1727.
- Dowd M and Joy R. 2011. Estimating behavioural parameters in animal movement models using a state augmented particle filter.
- Dowd M. 2011. Parameter estimation for nonlinear stochastic
dynamic systems with application to ocean biogeochemistry.
- Mattern JP, Fennel K, Dowd M. 2010. Introduction and Assessment
of Measures for Quantitative Model-Data Comparison Using Satellite
Images. Remote Sensing. 2(3), 794-818; doi:10.3390/rs2030794
- Mattern JP, Dowd M, Fennel, K. 2010. Sequential Data Assimilation
Applied to a Physical-Biological Model for the Bermuda Atlantic Time
Series Station Journal of Marine Systems. 79: 144-156
- Almeida EA, Dowd M, Flemming J, Li WKW. 2009. State Space Model
Extraction of Trends and Seasonal Variablity in Ocean Monitoring
Data. Limnology and Oceanography: Methods 7:883-847.
Zhai L, Platt T, Tang C, Dowd M, Sathyendranath S, Forget M-H. 2008. Estimation of phytoplankton loss rate by remote sensing, Geophysical Research Letters , 35, L23606, doi:10.1029/2008GL035666.
- Beech T, Dowd M, Field C, Hatcher B, Andrefouet S. 2008. A stochastic approach to
marine reserve design: incorporating data uncertainty. Ecological
Coll M, Palomera I, Tudela S, Dowd M. 2008. Food web dynamics in the
South Catalan Sea ecosystem (NW Mediterranean) for the period
1978-2003. Ecological Modelling 217:95-116
- Danielson RE, Dowd M, Ritchie H. 2008. Objective analysis of
marine winds with the benefit of Radarsat-1 synthetic aperture radar:
a nonlinear regression framework. Journal of Geophysical Research
113, C05019, doi:10.1029/2007JC004413
- Ikeda T, Dowd M, Martin JL. 2008. Application of functional data
analysis for investigating seasonal progression and interannual
variability in plankton. Estuarine Coastal and Shelf Science
Dowd M. 2007. A Discussion on "Parameter Estimation for Differential
Equations: A Generalized Smoothing Approach" by JO Ramsay, G Hooker, D
Campbell, and J Cao. Journal of the Royal Statistical Society Series
Dowd M. 2007. Bayesian statistical data assimilation for ecosystem
models using Markov chain Monte Carlo. Journal of Marine Systems
Cranford PJ, Strain PM, Dowd M, Hargrave BT, Grant J, Archambault
M-C. 2007. Influence of Mussel Aquaculture on Nitrogen Dynamics in a
Nutrient Enriched Coastal Embayment. Marine Ecology Progress
Grant J, Curran KJ, Guyondet TL, Guglielmo T, Bacher C, Koutitonsky V
and Dowd M. 2007. A box model for carrying capacity for suspensed
mussel aquaculture in Grand-Entree, Iles-de-la-Madeline,
Quebec. Ecological Modelling . 100(1-2):193-206.
Losa SN, Vezina A, Wright D, Lu Y, Thompson K,
XsyDowd M. 2006. 3D ecosystem modelling in the North
Atlantic: relative impacts of physical and biological
parameterizations. Journal of Marine
Systems . 61: 230-245.
Dowd, M. 2006. A sequential Monte Carlo approach to marine ecological
prediction. Environmetrics. 17:435-455.
Wong MC, Barbeau MA, Dowd M, Richard K. 2006. Behavioural
mechanisms underlying observed functional responses of sea stars
Asteris vulgaris preying on juvenille sea scallops Placopecten
magellanicus. Marine Ecology Progress Series
Dowd, M. 2005. A biophysical coastal ecosystem model for assessing
environmental effects of marine bivalve aquaculture. Ecological
Modelling . 183(2-3):323-346.
Greenberg DA, Shore JA, Page FH, Dowd M. 2005. A finite
element circulation model for embayments with drying intertidal areas
with application to the Quoddy region of the Bay of Fundy. Ocean
Dowd M, Martin JL, LeGresley MM, Hanke , Page FH. 2004. A
statistical method for the robust detection of interannual changes
in plankton abundance: Analysis of 1988-1999 monitoring data from the
Bay of Fundy, Canada. Journal of Plankton Research . 26(5):509-523.
Dowd, M. 2003. Seston dynamics in a tidal embayment with shellfish
aquaculture: a model study using tracer equations. Estuarine, Coastal
and Shelf Science . 57(3):523-537.
Dowd M, Meyer R. 2003. A Bayesian approach to the ecosystem
inverse problem. Ecological Modelling . 168:39-55.
Dowd M, Martin JL, LeGresley MM, Hanke A, Page FH. 2003. Interannual variability in a plankton time
series. Environmetrics . 14(1):73-86
- Perrie W, Dunlap E, Vachon PW, Toulany B, Dowd M. 2002. Marine winds from remotely sensed measurements.
Canadian Journal of Remote Sensing . 28:450-465.
Thompson KR, Dowd M, Shen Y, Greenberg D. 2002. Probabilistic
characterization of tidal mixing in a coastal embayment: a Markov
chain approach. Continental Shelf Research . 22:1603-1614
Dowd M, Vachon PW, Dobson FW, Olsen RB. 2001. Ocean wave
extraction from RADARSAT synthetic aperture radar inter-look image
cross-spectra. IEEE Transactions on Geoscience and Remote
Sensing . 39(1):21-37.
Thompson KR, Dowd M, Lu Y, Smith B. 2000. Oceanographic
data assimilation and regression analysis. Environmetrics . 11:183-196.
Dowd M, Thompson KR. 1999. "Errata for 'Forecasting coastal
circulation using an approximate Kalman filter based on dynamical
modes' ". Continental Shelf Research . 19:573-574.
Dowd M. 1998. On the estimation of circulation from density
observations in coastal and continental shelf regions. Continental
Shelf Research . 18:991-1014.
Dowd M, Thompson KR. 1998. Forecasting coastal circulation
using an approximate Kalman filter based on dynamical
modes. Continental Shelf Research . 17: 1715-1735.
Dowd M. 1997. On predicting the growth of cultured
bivalves. Ecological Modelling . 104:113-131.
Dowd M, Thompson KR. 1996. Extraction of tidal streams from a
ship-borne acoustic Doppler current profiler using a
statistical-dynamical model. Journal of Geophysical Research . 101:
Other Refereed Contributions:
Wong, M.C., Dowd, M., Bravo, M., Giroux, C., Haverstock, A., Humble,
M., MacFarlane, M., Roach, S., and Rowsell, J. 2016. Nekton in
Zostera marina (eelgrass) beds and bare soft-sediment bottom on the
Atlantic Coast of Nova Scotia, Canada: species-specific density and
data calibrations for sampling gear and day-night
differences. Can. Tech. Rep. Fish. Aquat. Sci. 3155: v + 40 p.
Dowd M., Wong, M.C., and McCarthy, C. 2014. Tidal Analysis in Little
Port Joli Basin, Kejimkujik National Park Seaside, NS: Before and
After Removal of Bridge and Causeway.
Can. Tech. Rep. Fish. Aquat. Sci. 3099: v + xx p.
Dowd, M. 2012. Dynamic modeling in Encyclopedia of Environmetrics
Second Edition, A.-H. El-Shaarawi and W. Piegorsch (eds). John
Wiley & Sons Ltd, Chichester, UK, pp. 733-736. DOI:
- Grant J, Dowd M, Chiu G. 2010. Indices of coastal ecosystem
health: a new paradigm. Canadian Technical Report of Fisheries and
Aquatic Sciences 2904.
Chamberlain J, Weise AM, Dowd M, and Grant J. 2006. Modelling
approaches to assess the potential effects of shellfish aquaculture on
the marine environment . DFO Can. Sci. Advis. Sec Res. Doc.
CSAS Research Document available online here
Wildish, D., M. Dowd, T. Sutherland, and C. Levings. 2004. Near Field
Organic enrichment from Marine Finfish Aquaculture. In: Volume III: A
Scientific Review of the Potential Environmental Effects of
Aquaculture in Aquatic Ecosystems. Canadian Technical Report of
Fisheries and Aquatic Sciences 2450. p. 1-42.
Cranford, P., M. Dowd, J. Grant., B. Hargrave, and
S. McGladdery. 2003. Ecosystem Level Effects of Marine Bivalve
Aquaculture. In: Volume I: A Scientific Review of the Potential
Environmental Effects of Aquaculture in Aquatic Ecosystems. Canadian
Technical Report of Fisheries and Aquatic Sciences 2450. p. 51-84.
Dowd, M., F. Page, and R. Losier. 2002. Time Series Analysis of
Temperature, Salinity, Chlorophyll and Oxygen data from Tracadie Bay,
PEI. Canadian Technical Report of Fisheries and Aquatic
Sciences 2441. 86pp.
Page F, Hanke A, Martin JL, Dowd M, LeGresley MM. 2002. Multivariate
community structure and time series analyses of phytoplankton from the
Bay of Fundy: some work in progress. Canadian Technical Report of Fisheries and Aquatic
Dowd, M., F. Page, R. Losier, P. McCurdy, G. Budgen. 2001. Physical
oceanography of Tracadie Bay, P.E.I.: Analysis of sea level, current,
wind and drifter data. Canadian Technical Report of Fisheries and
Aquatic Sciences 2347. 80pp.
Singh, R., M. -I. Buzeta, M. Dowd, J.L. Martin,
M. LeGresley. 2000. Ecological Overview of Musquash Estuary: A
Proposed Marine Protected Area. Canadian Manuscript Report of
Fisheries and Aquatic Sciences 2538. 39pp.
Grant, J., M. Dowd, K.R. Thompson, C. Emerson and A. Hatcher. 1993.
Perspectives on field studies and related biological models of bivalve
growth and carrying capacity. In: Bivalve Filter Feeders in Estuaries
& Coastal Marine Ecosystem Processes . (R. Dame, ed.) Springer
Verlag. pp. 371-420.