Characteristics of PDV and the need for a PDV research and monitoring Nate Mantua JISAO/SMA Climate Impacts Group University of Washington

November-April SLP change: ( ) - ( )

Cool season Aleutian Low variability: (Nitta and Yamada 1989, J. Met. Soc. Japan; Trenberth 1990, BAMS) North Pacific winter sea level pressure field (i.e. the Aleutian Low) “shifted” in 1977

The Pacific Decadal Oscillation an El Niño-like pattern of climate variability 20 to 30 year periods of persistence in North American and Pacific Basin climate warm extremes prevailed from , and again from ; a prologed cold era spanned ? (Mantua, Hare, Zhang, Wallace and Francis 1997, BAMS)

Todd Mitchell, UW/JISAO Warm phase PDO and North American climate temperatureprecipitation

Wavelet of NPI & PDOI Minobe (1999 GRL; 2000 Prog. Oceanogr)

Some key unanswered questions How many decadal/interdecadal modes are there in Pacific climate? What are their dynamics and predictability? Can we detect phase changes soon after they take place?

Distinct modes of NP SST variability? from a Rotated PC analysis of COADS SST (Nigam et al. 1999, Eos Trans.)

Slowdown of the meridional overturning circulation in the Tropical Pacific ~25% decrease in upwelling from 1970’s to 1990’s, rising eq. SSTs and a reduced CO 2 flux to the atmos McPhaden and Zhang, Nature,2002

P

OCEANIC AND ATMOSPHERIC EVIDENCE FOR A PACIFIC DECADAL OSCILLATION (PDO) PHASE SHIFT AFTER 1998 Gary S. E. Lagerloef, Earth and Space Research, Seattle, WA, USA Patrick Cummins, Institute of Ocean Sciences, Sidney BC, Canada Jeffrey Polovina, NOAA/NMFS, Honolulu, HI, USA Gary T. Mitchum, University of South Florida, St. Petersburg, FL, USA 1 Mantua et al. (1997), 2 Lagerloef (1995) 1 2

PDV and marine ecosystems

Alaska Commercial Salmon Catches Alaska Department of Fish and Game

Bottom trawl surveys in Pavlov Bay, Alaska (source: Botsford et al Science) 1960’s 1970’s 1980’s Ecosystems change

Pavlov Bay, Alaska Trawl surveys (Anderson and Piatt 1999, Mar. Ecol. Prog. Ser.)

Pacific Sardines: a history of 20th Century boom and bust cycles (Kawasaki and Omori 1988)

Sardines, Anchovies, climate and carbon Chavez et al. 2003, Science

Chavez et al. 2003, Science

PDV projects: revised outline I.INTRODUCTION: motivation II. the nature of PDV 1.Instrumental Description of PDV 2.Paleo-reconstructions of PDV III. PDV modeling, mechanisms and predictability 1.PDV observing strategy: past and future 2.mechanisms of PDV in coupled models 3.Prediction and predictability of PDV 4.PDV and land surface feedbacks 5.PDV and global warming IV. PDV impacts: mechanisms and predicting impacts 1.Fisheries/Marine food webs 2.water resources 3.Energy, fire, Human health, Ag?

7. Observations System Simulation Experiments for PDV in coupled models The problem? Need to design a purposeful monitoring system for PDV modes Why is it important? Background observing system planned for CLIVAR may not be sufficient for PDV nowcasts or forecast initializations What has been done so far? nothing What needs to be done? Simulated predictions (as suggested in item 6) with degraded initial conditions What will be different if it is done? PDV monitoring needs can be compared with planned and existing capabilities

Feb 2003 PDV workshop A small two day workshop organized by Ed Sarachik, Nate Mantua, and David Legler to discuss and revise a draft prospectus for a PDV science program And ftp://ftp.atmos.washington.edu/mantua/PDV