Summary session 5. Structure & outcomes Before coffee break – Surface subsurface climate...
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Transcript of Summary session 5. Structure & outcomes Before coffee break – Surface subsurface climate...
Structure & outcomes
• Before coffee break – Surface subsurface climate variability
• After coffee break– Oxygen & nutrient – Fisheries
• Outcomes– Updated synthesis of climate processes in the N-Pac– Interpret IPCC5 projections in the context of N-Pac
Cliamte dynamics
Mat Collins
• Anomalies 1986-2005 average. • Transient climate response is likely in the
range 1-2.5C and extremely unlikely greater than 3c. (box 12.2)
• My interest: Tropical atmospheric circulation is weakened, subtropics creeps poleward.
• Five consistent models show faster reduction of sea-ice.
Mat Collins 2
• SAT change 2081-2100 minus 1986-2005– Global mean, land-sea contrast, polar amplification
(themodynamic processes) are removed. Then PICES region is fastest warming
– Dynamical SAT changes seem much smaller – although of crucial in the tropics (Xie et al. 2010)
• Vertical winds (omega) = precipitation (P) / humidity (q) – This relation is good for global, but not in Asian – Chadwick et al. (2013)
Mat Collins 4
• Chapter 14: climate phenomne and their relevance for future regional climate change
• Any specific projected change in ENSO variability in the 21st century remains low. Associated precipitation changes will be intensified.
• Extreme El Ninos (Cai et al, Nature Climate Change 2014) will be doubled.
Mat Collins
• Changing El Nino teleconnections associated with Walker Circulation Change – Chung et al. Cdyn 2014– Power et al. Nature 2013
Mat Collins
• Global warming ‘pause’ or ‘hiastus’ (Box 9.2)• Chris Roberts, Matt Palmer, MO– Pseudo ensemble hiatus from piControl + forced
response – 2001-2010 negative trend (11.5%). Hiatus can occur
by chance. – 2001-2015 negative trend (0.8%) – Composite mean pattern of hiatus has PDO pattern
in the Pacific (with amplitudes in Indian and Atlantic Oceans), consistent with observation.
Mat Collins
• Trade wind strengthening: England et al. Nature Climate Change 2014– See also Kosaka and Xie 2013
Mat Summary
• Large-scale thermodynamic response of temp relatively well understood; global + land/sea + polar amplification. Could build a quantitative theory. – Interestingly, after removal of them SAT change is
largest PICES region. Can be associated with polar amplification (just masking)
• Precip: weakened circulation and increase humidity • Challenge is to combine information from
imperfect models with our (sometimes quite good) understanding of physical processes.
Nate Mantua
• 1998-2013 minus 1977-1997• Max corr. Is 0.53 Beween negative pole in C-N-
Pac and pole in E-N-Pac. • ER-SST (1900-2012) USHCNv2 GHCNv3 (1900-
2012), flux SODA (1900-)• EOF east of dateline (max corr 0.82): horse
shoe-oval still (ship track is good in this region)• SLP PC1 max at 150W, 35N (shifted east than
NPI)
Nate Mantua 2
• SST = 0.81 SST(t-1) + 0.27 SLP(t) + eps(t) (monthly)– Good reconstuction =0.79 (monthly)
• SST tendency due to latent heat flux, horizontal Ekman transport, vertical T-advection
• Coastal air-temperature は annual meanでよく一致.• SLP forcing accounts for all of the SST trend & most of
SAT trend (from northern California to Washington) • Circulation changes looks to be free (not forced) from
4 CMIP5 models (31 members), consistent with Deser et al. (2012, 2014), Oshima et al. (2012)
Mat Newman 1
• PDO is reddened ENSO + lagged KOE due to Rossby waves – PDO (yr) = 0.6 PDO (yr-1) + 0.6 ENSO(yr) + eps
• Multivariate red noise (Ornstein-Uhlenbeck)– dx/dt = B x + fs – If B is nonnormal (not symmetric), transient anomaly
growth is possible even through exponential growth is not.
– Detemine B with LIM from lagged covariance (space and time) statistics of X
Matt Newman 2
• LIM, State variable – Pacific SST – Tropical thermocline depth (20C isodepth) – N-pac mixed layer (30-100 m)
• Seasonality is ignored • B determined from 3 month lag• Result is flat to 0.02 cycle/yr
Mat Newman 3
• After removal tropical forcing, Oyashio SST anomalies stand out
• Trend + KOE-related + decadal ENSO (aka CP ENSO)
• PDO may generally provide only weak forcing of the atmosphere (Kumar et al. 2012)
• Smirnov et al. (2014) HR model KOE -> G Alaska
Bo Qiu 1
• Unstable states lagged by 4-yrs to PDO, 3-yr to NPGO. Due to Rossby waves. – Stable -> strong gradient?
• KE index: sum of four indices, extended using OFES to 1956 (just SSH anomaly in KE region).
• two way prediction model has a better skill 4-5 years
• Northward-shifted and stable KE will last further several years. (Qiu 2014 JC)
Nikas 1
• Taguchi & Schneider JC 2014 submitted• 0-300 m HC propagate eastward • Higher vertical mode• Density-spiciness split– δT = d[T]/dρ δρ + δ T’ (vertical movement +
spiciness) – Spiciness is dominant – Meridional displacement produces spiciness
Niklas 2 summary
• Westward propagating SSHa• Eastward propagating OHCa– Generation meridional migration – Mean advection – Damping produces higher vertical modes
Krovnin 1
• Azores high & icelandic low longitudes and Z500 – 1950-1977: – 1978-2005:
• Atlantic influence -> Eurasia -> North Pacific• Ocean tracers as integrators– Long memory -> red noise (Ito & Deutsch 2010;
2013)– Double integration (Di Lorenzo & Ohman 2013)
Taka Ito 1• Declining oxygen – Coastal hypoxia (Diaz and Rosenberg 2008; Bograd
et al. 2008)– Expanding/shaling oxygen minimum zone (OMZ)
(Stramma et al., 2008; 2010; Helm et al. 2011)• What controls subsurface O2– Oxygen <-> productivity -> respiration = O2
utilization
Taka Ito 2
• Helm et al. (2011) WOCE vs historic data 1992-1970 in 100-1000 m
• 1990-2008 minus 1960-74 diff (Stramma et al. 2010) O2 decline <- AOU increase in the topical oceans
• Warming • Weakening ocean vertical exchange – Weaker physical O2 -> weaker nutrient upwelling ->
weaker productivity • Tropics incease oxygen (Cocco et al. 2013)
Taka Ito 3
• Tropical O2 paradox – There are a number of suggestions including
decadal variability of Deutsch et al. (2011) – This study : anthropogenic nutrient flux – Mineral Fe : acidification aerosol makes solble
iron. – Anthropogenic Fe decomposition promoves ocean
productivity (Krishnamurty 2009?)
Taka Ito 4
• Global 1x1, L23 (MITgcm –Ecco) • 2 biogeochemistry models • Soluble Fe flux 100 years-> macro nutrient
down -> productivity up -> O2 down – This effect is not in CMIP5 models.
• This can explain the reduction of topical oxygen reduction.
Sung Yong Kim (KAIST)
• CalCOFI region • 6 harmonics T, T/2, T/3 … T/6 • Fitted with seasonal cycle, ENSO, PDO, NPGO,
trend
Di Lorenzo
• Good coastal hypoxia map (Diaz and Rosenberg Science 2008)
• Isopycnal 26.5 • d O’shelf /dt = -(1+r) w’ [Osub] + [w] Osub’ –
eps O’shelf• Northward poleward undercurrent bring low
O2 (high NO3) from the south• Gyre brings high O2 (low NO3)
Di Lorenzo 2
• Salinity anomalies in ECMWF ORA3 on isopycnal 26.5 is used as a proxy of Oxygen– Good in ColCOFI and Statin P – CalCOFI papers: Bograd et al 2008; Koslow et al
2011; Peterson et al. 2013• Subtropical gyre in the central Pacific N-Pac
oxygen (index) can predict CalCOFI oxygen with lag of 8-10 years
Art Miller 1
• CCE-LTER founded in 2004• Rykaczewki and Checkley (2008): off-shore
Ekman pumping is important as coastal upwelling
• Warm water coming from depth
Shin-ichi Ito
• Pacific saury: subarctic feeding, subtopics spawning, Surf riding theory
• Examine using NEMURO.FISH• Previous 3box -> Euler model – Velocity (Ambe 08) 1/3 deg, temperature (MODIS/Terra 1/12
deg), Chl-a SeaSiFS (1/12 deg)• Feeding migration: highest grwoth, spawning migration, • Order is good, but interannual variation 2002-2009 is
not good enough– Adjust westward migration speed. ->
Shin-ichi Ito 2
• Westward migration is low in 2004 high in 2008– SST west is warmer (cooler in east) -> faster
westward migration – Saury may see light (cloudiness)
Sukgeun Jung
• Pacific cod (cold water spices) in Korea waters increase from 1999 to 2011.
• Common squid (warm water) dominant • Increase Sardine (warm) and Cod (cold) since
the late 1990s. • Corresponding analysis -> dim1 & dim2 – Dim1 is correlated to temp 100-500 m