what we’ve done since june 2007

Michael SteelePolar Science Center / APLUniversity of Washington

Jan 28, 2008Arctic PP obs

wkshpSeattle, WAWhat we’ve done since June What we’ve done since June

20072007

Michael Steele & Wendy ErmoldPolar Science Center / Applied Physics Laboratory / University of Washington,

Seattle WA USA

• Web site

• Animation script consultation

• SST study updated through 2007

• Freshwater studies with (i) Polyakov & (ii) Rawlins/Serreze

• PHC update

• Start of seasonal/annual mean PP analysis



wkshpSeattle, WA

The web pageThe web page



wkshpSeattle, WA

PeoplePeople



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GraphicsGraphics

How to organize our new synthetic plots?



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DataData

How to organize our new synthetic DATA?



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OutreachOutreach

Animation…Animation…



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LinksLinks

• Others?

• Announcement on ArcticInfo?



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Private SectionPrivate Section

Username: mas

Password: st33l3



wkshpSeattle, WAAnimationAnimation::

1:30 pm today1:30 pm today

SST study:

• Refresher on bias & binning issues/techniques

• Updated through 2007

…using satellite data & model output

SST study:

• Refresher on bias & binning issues/techniques

• Updated through 2007

…using satellite data & model output



wkshpSeattle, WASPATIAL BIASSPATIAL BIAS

Mean SST = 2.2 C Mean SST = 1.9 C

Example: East Siberian + eastern Laptev Seas

Temperature (ºC)

Raw Data 50km bin averaged

dense dense WARMWARM profiles profiles

sparse sparse COLDCOLD profiles profiles

PP binning: getting done!PP binning: getting done!



wkshpSeattle, WAFake trendsFake trends

Year 1 Year 2 Year 3

cold

warmer

hot

datadatadatadata

Solution: subtract out the mean spatial field

Trend analysis: still to doTrend analysis: still to do

spatially biased samplingspatially biased sampling fake regional-average fake regional-average warmingwarming trend trend



wkshpSeattle, WA

World Ocean Database ’05(in situ data)

Beaufort-W

summer

Mean summer (Jul-Aug-Sep) Sea Surface Temperature (SST)

(0-10 m)

50 km bins



wkshpSeattle, WA

Summer (jul/aug/sep) SST trends: regional anomalies

Summer (jul/aug/sep) SST trends: regional anomalies

(f) Chukchi

(a) Beaufort-E

(c) Bering St

(e) Kara

(d) ESS+ Laptev

(b) Beaufort-W

sum

mer

SST

(C

)

Reynolds et al

recentwarming

recentwarming

recentwarming

in situin situsatellitesatellite

WOD’05

smoothedsmoothed

3.25 std dev3.25 std dev

3.05 std dev3.05 std dev

sum

mer

SST

(C

)su

mm

er S

ST (

C)

mean =mean = 2.7°C 2.7°C mean =mean = 0.4°C 0.4°C

mean =mean = 5.9°C 5.9°C

mean =mean = 3.1°C 3.1°C mean =mean = 2.9°C 2.9°C

mean =mean = 2.3°C 2.3°C

Is warming starting to matter to PP?



wkshpSeattle, WA

Ocean heat fluxes: Ocean heat fluxes: summer summer 20072007

(Jul-Aug-Sept)(Jul-Aug-Sept)

Surface heating (Fsw)

ice

Everywhere!Chukchi + w. Beaufort

Lateral heat flux convergence

ice

…using Jinlun Zhang’s ice-ocean model

ocean currents are important north of Alaska

but most places, it’s solar heating



wkshpSeattle, WA

(1) Polyakov et al.…in press

(1) Polyakov et al.…in press

Russian shelf anomalies are:

(a) out of phase with central

Arctic Ocean

(b) much smaller than central

Arctic Ocean anomalies

Freshwater studiesFreshwater studiesFreshwater studiesFreshwater studies

(2) Rawlins et al. …in prep. (2) Rawlins et al. …in prep.

Mackenzie R.

24% fresher with variable river discharge24% fresher with variable river discharge

TerrestrialP-E incr.

’96/’97

Riverdischarge incr.

’96 – ‘98

Lakedischarge incr.

’98

Oceanshelf FW incr.

’96

Sea ice melt decr.

’97/’98

Beaufortgyre FW incr.

’97-’02



wkshpSeattle, WA

PHC updatePHC update

• Fram Strait / EGC

• Bering St / Siberian shelves

• MLD lobes …later

…in progress……in progress…



wkshpSeattle, WA

Seasonal/annual mean PP analysis

…later…



wkshpSeattle, WA

Ongoing:

• Update our T, S data base

with data from 1990s & 2000s

Barely started:

• MLD/stratification temporal change study



wkshpSeattle, WA



wkshpSeattle, WA

XCP

satellite SST

SST + MLD = heat contentoverestimate

model

But! Model’s heat contentunderestimated?

Conclusions:

• Ocean transport < shortwave …probably

• Need further analysis of the in situ IPY data!

Courtesy of J. Morison, F. McLaughlin, A. Proshutinsky

Chukchi Borderland (75.7°N, 156°W) Aug 7, 2007

Heat content uncertaintyHeat content uncertaintyHeat content uncertaintyHeat content uncertainty

Temperature (°C)-2 0 2 4

Dep

th (

m)

100

50

0

Beaufort Slope (70.8°N, 140°W) Aug 1, 2007D

epth

(m

)

0

50

100

Temperature (°C)-2 0 2 4

modelmodel

obsobs

Maybe not everywhere…



wkshpSeattle, WA

WOD’05WOD’05data distribution,data distribution,

colored by: colored by:

Temperature (ºC)

Years

TemperatureTemperature

Earliest YearEarliest Year

0-10 mJuly, Aug, Sept



wkshpSeattle, WA

Raw data histograms

Temporal BiasTemporal Bias



wkshpSeattle, WAThe solution: Multiple Regression

T = a + bx + cy + dPHC(x,y) + eyear

spatial fieldspatial field

Anomalies are defined relative to the mean spatial field over a given time period.

…no “intra-year” predictor

^



wkshpSeattle, WA

July-Aug-Septsatellite SSTanomalies

(rel to 1982-2007)

July-Aug-Septsatellite SSTanomalies

(rel to 1982-2007)

Temperature Anomaly (C)

2000 2001 2002

200520042003

2006 2007

boring!

2007:What a year!

Max Anom 5°CMax Anom 5°C

Sept 16

1982-2007:



wkshpSeattle, WAHow much

warming is fromocean transport?

ice

20-30%20-30%

-1 -0.5 0 +0.5 +1

Alaska

Russia

lateral heat flux convergencenet ocean heating

100%100%

fadv

fadv

Jul-Aug-Sep 2007

what we’ve done since june 2007

Documents