1. What we’ve done since June 2007
Michael Steele & Wendy Ermold
Polar 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

2. The web page

3. People ?

4. Graphics
How to organize our new synthetic plots?

5. Data
How to organize our new synthetic DATA?

6. Outreach
Animation…

7. Links
Others?
Announcement on ArcticInfo?

8. Private Section
Username: mas
Password: st33l3

9. Animation: 1:30 pm today SST study:
Refresher on bias & binning issues/techniques
Updated through 2007
…using satellite data & model output

10. SPATIAL BIAS Example: East Siberian + eastern Laptev Seas
Raw Data
50km bin averaged
Mean SST = 2.2 C
Mean SST = 1.9 C
sparse COLD profiles
dense WARM profiles
Temperature (ºC)
PP binning: getting done!

11. Solution: subtract out the mean spatial field
Fake trends
Year 1
Year 2
Year 3
steady state ocean
cold
warmer
hot
data
spatially biased sampling
 fake regional-average warming trend
Solution: subtract out the mean spatial field
Trend analysis: still to do

12. Mean summer (Jul-Aug-Sep) Sea Surface Temperature (SST) (0-10 m)
Beaufort-W
World Ocean Database ’05
(in situ data)
summer
50 km bins

13. Summer (jul/aug/sep) SST trends: regional anomalies
in situ
WOD’05
satellite
Reynolds et al
smoothed
summer SST (C)
mean = 2.7°C
mean = 0.4°C
recent
warming
(a) Beaufort-E
(b) Beaufort-W
3.25 std dev
summer SST (C)
recent
warming
mean = 5.9°C
mean = 2.3°C
Beaufort-East seems out of phase with Beaufort-West, which probably relates with sea ice circulation (Barnett Severity Index increases as Beaufort-West increases) but also maybe with Pacific Water changes However, recently we see warming in both regions
Bering St area is boring! Until recent warming
ESS+Laptev confirms the sea ice influence discussed in previous slide Ice thickness is from Zhang’s model Anomalously thick ice in the spring (1960s) leads to cooler SST, while anomalously thin springtime ice (1990s) leads to warmer SST
Kara might show decadal oscillations, but the data are sparse
Chukchi boring until recent warming
(c) Bering St
(d) ESS+ Laptev
3.05 std dev
recent
warming
summer SST (C)
mean = 3.1°C
mean = 2.9°C
(e) Kara
(f) Chukchi
 Is warming starting to matter to PP?

14. Ocean heat fluxes: summer 2007
(Jul-Aug-Sept)
…using Jinlun Zhang’s ice-ocean model
Lateral heat flux convergence
Surface heating (Fsw)
ice
ice
Chukchi + w. Beaufort
Everywhere!
ocean currents are
important north of Alaska
but most places,
it’s solar heating

15. Freshwater studies 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
(2) Rawlins et al. …in prep.
Mackenzie R.
24% fresher with
variable river discharge
Terrestrial
P-E incr.
’96/’97
River
discharge incr.
’96 – ‘98
Lake
discharge incr.
’98
Ocean
shelf FW incr.
’96
Sea ice
melt decr.
’97/’98
Beaufort
gyre FW incr.
’97-’02

16. PHC update …in progress… Fram Strait / EGC Bering St /
Siberian shelves
MLD lobes …later
…in progress…

17. Seasonal/annual
mean PP
analysis
…later…

18. Ongoing:
Update our T, S data base
with data from 1990s & 2000s
Barely started:
MLD/stratification temporal change study

20. Chukchi Borderland (75.7°N, 156°W) Aug 7, 2007
Heat content uncertainty
model
satellite SST
But!
Model’s
heat content
underestimated?
SST + MLD = heat content
overestimate
XCP
Beaufort Slope (70.8°N, 140°W) Aug 1, 2007
Depth (m) 50
100
Temperature (°C) -2 2 4
model
obs
Maybe not everywhere…
Depth (m) 50
Chukchi Borderland (75.7°N, 156°W) Aug 7, 2007
100 -2 2 4
Temperature (°C)
Conclusions:
Ocean transport < shortwave …probably
Need further analysis of the in situ IPY data!
Courtesy of J. Morison,
F. McLaughlin, A. Proshutinsky

21. WOD’05 data distribution, colored by:
Temperature (ºC)
Temperature
Years
Earliest Year
0-10 m
July, Aug, Sept

22. Temporal Bias
Raw data histograms

23. The solution: Multiple Regression
T = a + bx + cy + dPHC(x,y) + eyear ^
spatial field
Anomalies are defined relative to the mean spatial field over a given time period.
…no “intra-year” predictor

24. July-Aug-Sept satellite SST anomalies (rel to 1982-2007)
Temperature Anomaly (C)
July-Aug-Sept satellite SST anomalies (rel to )
2000
2001
2002 :
boring!
2003
2004
2005
1980s – 1990s: Warm, cool anomalies, nothing obviously spectacular (“ehh…”)
Early 2000s: some warm years, what I would have said were VERY warm until 2007!
2007: Crazy ass warming, obviously tied to ice retreat Too fast and too strong for Pacific Water to be major cause: it’s got to be mostly solar heating But we want to work with Perovich’s SASS group to better understand this
2007:
What a year!
Max Anom  5°C
2006
2007
Sept 16

25. lateral heat flux convergence
How much warming is from
ocean transport?
lateral heat flux convergence
net ocean heating
fadv 
Russia
ice
20-30%
100%
Alaska
Jul-Aug-Sep 2007
fadv