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

The web page

People ?

Graphics How to organize our new synthetic plots?

Data How to organize our new synthetic DATA?

Outreach Animation…

Links Others? Announcement on ArcticInfo?

Private Section Username: mas Password: st33l3

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

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!

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

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

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?

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

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

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

Seasonal/annual mean PP analysis …later…

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

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

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

Temporal Bias Raw data histograms

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

July-Aug-Sept satellite SST anomalies (rel to 1982-2007) Temperature Anomaly (C) July-Aug-Sept satellite SST anomalies (rel to 1982-2007) 2000 2001 2002 1982-2007: 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

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 -1 -0.5 0 +0.5 +1 Jul-Aug-Sep 2007 fadv