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1 Exploring the Potential of NCEP’s GODAS and CFS to Diagnose and Forecast Coastal Upwelling for California Current Ecosystem Yan Xue, Boyin Huang Climate.

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Presentation on theme: "1 Exploring the Potential of NCEP’s GODAS and CFS to Diagnose and Forecast Coastal Upwelling for California Current Ecosystem Yan Xue, Boyin Huang Climate."— Presentation transcript:

1 1 Exploring the Potential of NCEP’s GODAS and CFS to Diagnose and Forecast Coastal Upwelling for California Current Ecosystem Yan Xue, Boyin Huang Climate Prediction Center Janine Fisler University of Maryland at College Park Acknowledgement: Wayne Higgins, Frank Schwing, Wanqui Wang, David Behringer, Arun Kumar

2 2 Rationale  Coastal upwelling brings nutrients from depth to the surface  Coastal ecosystems flourish in nutrient-rich waters  Monitoring and forecasting upwelling benefits ecosystem and fishery managers

3 3 Upwelling in California Current Ecosystem Ekman Transport ~ along shore wind stress Pickett and Paduan, 2003 Huyer, 1983 Ekman Pumping ~ wind stress curl North of 36˚N upwelling seasonally South of 36˚N upwelling year-round Onset of Upwelling season progresses from March to July along the coast Both onset date and intensity during upwelling season extremely important

4 4 Upwelling Index (UI) (Southwest Fisheries Science Center)  Use NAVY’s FNMOC 3 o x 3 o and 1 o x 1 o Sea Level Pressure fields (6-hourly, monthly data since 1967)  Calculate geostrophic winds from SLP  Use along shore wind stress to calculate Ekman transport  SWFSC’s UI is the only routine upwelling product (500 references) 15 Standard Sites

5 5 Global Ocean Data Assimilation System (GODAS) Background:  Assimilates temperature profiles, synthetic salinity, altimetry into GFDL Modular Ocean Model v.3  Provides oceanic initial conditions for Climate Forecast System (CFS)  75˚S to 65˚N with resolution of 1˚ by 1˚  40 vertical levels, with 10m resolution in the upper 200m  Pentad temporal resolution  Forced by atmospheric Reanalysis 2 (R2) fields Advantages:  Ability to monitor ocean in near-real time (7 day lag)  Can use marine fields instead of winds to approximate upwelling, e.g. vertical velocity at 50-meter depth  Coupled with CFS: potential for prediction

6 6 SWFSC vs. GODAS UI: Climatology Baja 60 o N large disagreement South of 39 o N large disagreement 57 o N – 39 o N good agreement

7 7  Compare both monthly and pentad upwelling  Climatology: 1982- 2004 for both data sets  High correlation between 36 o N - 57 o N  Low correlation north of 57 o N and south of 36 o N SWFSC vs. GODAS UI: Anomaly Correlation

8 8 Which index is more accurate?  Few in situ observations to validate indices  Difficult to make in situ observations Problem:  Derive upwelling index using NCEP surface wind analyses (R1, R2, GDAS) similar to SWFSC index  Verify GODAS and SWFSC, NCEP wind-derived indices against with that derived from QuikScat winds, Approach: See Poster P1.3 “Multiple Coastal Upwelling Indices for the Western Coast of North America” by Boyin Huang, Yan Xue and Frank Schwing

9 9 Cumulative Upwelling Index: CUI  Following Schwing et al., 2006  Calculate pentad date of climatological onset of upwelling season, “start date” (SD)  Calculate pentad date of maximum climatological upwelling, “maximum date” (MD)  Annually integrate upwelling index from SD to MD  Describe both total and anomalous upwelling Schwing et al., 2006

10 10 CUI 2005: Delayed Upwelling 48N 45N 39N 36N 33N 42N GODAS SWFSC

11 11 (from David Foley, NOAA NESDIS) 2002 Strong Upwelling 2005 Weak Upwelling SST Phytoplankton

12 12 CUI 2006: Healthy Upwelling 48N 45N 42N 39N 36N 33N GODASSWFSCGODASSWFSC

13 13 Standardized CUI Anomaly CUIA shifted from below- to above- normal in 1998 coincident with PDO shift Below-normal years: 88, 93, 97, 05 Above-normal years: 99, 01, 02, 03, 06 Poor agreement before 1985 Below-normal years tend to have positive PDO and NINI3.4 88 93 9705

14 14 Composites for Below-Normal Years AMJ (1988, 1993, 1997, 2005) Positive PDO and warm NINO4 SST Anomalous low SLP in NP Cyclonic surface wind anom. consistent with SLP Upwelling dipole at 40N-45N W at 50 m depth

15 15 Depth Temp at DepthsW at Depths Warm SST anom. above 50-meter depth Upwelling reaches 300-meter depth at least 48N: Upwelling extends 3 o offshore 42N-45N: Upwelling confined within 0.5 o of the coast

16 16 Target AMJ 0 Month Lead April 1 I.C. 5 members CFS Forecast

17 17 Target AMJ 1 Month Lead March 1 I.C. 5 members CFS Forecast 1 month lead is not as skillful as 0 month lead

18 18 Collaboration between NCEP and SWFSC through CTB Proposal Use high-resolution CFSRR winds and other NCEP reanalysis winds to improve the accuracy of estimations of coastal upwelling Determine skill of CFS to forecast variations in coastal upwelling Develop a biologically effective upwelling and transport index (BEUTI) using winds and upper-ocean density structure Determine model deficiencies and model requirements for coastal applications Real time monitoring and forecasting products of coastal upwelling

19 19 Backup Slides

20 20 0 Month Lead, AMJ April 1 Initial Condition 5 members

21 21 Critical Factors Controlling Primary Productivity and Ecosystem Health  Timing, intensity, and duration of Upwelling  Stratification of water column  Surface water temperature  Turbulence  Freshwater input/salinity  Position of Jet Stream  Light availability, etc. Giant Kelp

22 22 Annual Normalized CUI Anomaly: 1983 CUIA

23 23 Annual Normalized CUI Anomaly: 1986 CUIA

24 24 Annual Normalized CUI Anomaly: 1988 CUIA

25 25 Annual Normalized CUI Anomaly: 1993 CUIA

26 26 Annual Normalized CUI Anomaly: 1997 CUIA

27 27 Annual Normalized CUI Anomaly: 2005 CUIA

28 28 Annual Normalized CUI Anomaly: Disagreements

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