Ocean Model Impact Study Proposal for 2015

Transcription

1 Ocean Model Impact Study Proposal for 2015 OMITT-1 Background: HWRF w/ 3D POM-TC Yablonsky et al. (2010 IHC) confirmed POM tended to under-cool in response to prescribed wind stress based on observed TC winds, when compared against buoy composites. Positive bias. Kim et al. (2012) showed a similar under-cooling, when compared against MW remote sensing daily composites. Positive bias. Tallapragada et al. (2014) in the 2014 pre-implementation T&E Negative bias. HWRF w/ 1D & 3D POM-TC: real simulations in EPac. Negative bias. HWRF w/ GFS SST Kim et al. (2014) in a study of the WNP TC forecasts: no cooling, hence infinite positive SST feedback. Almost Perfect Forecasts, followed by negative (> 72h) in 2012; followed by positive bias (> 96 h) in 2013.

2 Ocean Model Impact Study Proposal for 2015 Ocean Model Impact Tiger Team (OMITT) OMITT-2 Overarching Objective: Demonstrate, understand, and improve ocean model impacts on coupled HWRF forecasts Difficult quest Improved ocean model performance does NOT always lead to improved TC forecasts. Ocean model improvement can expose deficiencies in the atmospheric model and in surface flux parameterizations. The reverse is also true. Improvement in coupled TC forecasts will be a long-term iterative process. This proposed project will initiate this process by documenting and understanding ocean model impacts and devising strategies to improve ocean model performance

3 Goals and Approach (provisional) Goal 1: Impact of no ocean coupling Implement an idealized version of HWRF coupled to a 1-D ocean model Conduct idealized twin experiments, uncoupled versus 1-D evaluate ocean response. Goal 2: Impact of coupling to 1-D versus 3-D ocean model Forecast models to be used MPIPOM-TC HYCOM 1-D HYCOM & POM Conduct experiments for multiple real storms comparing fixed SST (uncoupled), 1-D coupling, and 3-D coupling. Goal 3: Evaluate and compare different 3-D ocean models Physics-based ocean model evaluation Compare models to each other and each model to observations. Goal 4: Recommend strategies to improve ocean model performance (will be revised based on consensus of team members) OMITT-3

4 Ocean Model Impact Tiger Team OMITT-4 Hyun-Sook Kim (EMC) (co-chair) George Halliwell (AOML) (co-chair) Ligia Bernardet (DTC) Pete Black (NRL) Sue Chen (NRL) Joe Cione (HRD) Jili Dong (EMC/AOML) Isaac Ginis (URI) Benjamin Jaimes (U Miami) Beth Sanabia (USNA) Nick Shay (U Miami) Biju Thomas (URI) Eric Uhlhorn (HRD) Lin Zhu (EMC) addition by recommendation and/or volunteering.

5 A) CASES (Provisional) Candidate Storms to be decided upon consensus among team participants 2014 Edouard (ATL), Fengshen (WNP) 2013 Ingrid (ATL), Soulik (WNP), Haiyan (WNP) 2012 Nadine (ATL), Leslie (ATL), Isaac (ATL), Sandy (ATL) 2010 Earl (ATL)* 2008 Gustav (ATL)* 2005 Katrina (ATL), Rita (ATL) 2004 Ivan (ATL), Frances (ATL) (HWRF not available) OMITT-5 B) OCEAN MODELS i) 1D Idealized Cases different mixing physics Real Cases HYCOM & MPI-POM-TC ii) 3D Real Cases only - MPI-POM-TC - HYCOM C) Persistent SSTs - GFS coarse SST nowcast - High resolution GFS SST nowcast, e.g. NCODA Analysis - High resolution GFS SST, e.g. global HYCOM SST nowcast

6 D) Data (first cut) - Target obs. 1) SS funded ATL: Cione (HRD), IFEX and Shay (RSMAS) for Edouard ATL: Goni et al. (AOML,EMC) for Bertha, Cristobal, Gonzalo WNP: Bond (JISAO) & Cronin (PMEL) Fengshen and Nuri 2) P3, GH, HS3, and WC-130J Isaac (2012) & Sandy (2012); Iselle (2014). Historical TCs - Regular obs. + Funded by other programs 1) NDBC surface and subsurface obs. 2) ARGO, moorings, etc. OMITT-6 Caveats: Due to potential different physical processes, each basin may require different parameterizations. E) Metrics and Tools - Ocean diagnostic metrics decided during the 2009 HFIP air-sea interaction workshop. - Building diagnostic tools: Transfer to operational. F) Prepare a report to be presented at the 2015 HFIP annual meeting.

7 Efforts made in the Past: Example Presented in 2012 IHC by Bernardet, et al. (2012) OMITT-7 Uhlhorn and Cione (2012): 2012 operational HWRF run retrospectively for 2011 storms under-cools relative to buoy composites. Example: Katia initialized 09/01/2011, 12 UTC Buoy passage 9/4 12Z Reasonable track forecast Good Intensity forecast Poor ocean cooling forecast The right result (good intensity forecast) was obtained for the wrong reasons (compensating errors between the atmospheric and ocean models)

8 2014 Observations available (1) OMITT-8 Cione, IFEX, RSMAS: TC Edouard 26 ocean probes 8 BT 11 CP 7 CTD 3 days prior to storm Specific depths OML Z26 Z20 SMARTS: Systematically-merged Atlantic Regional Temperature and Salinity Climatology (Meyers et al. 2014)

9 OMITT Observations available (2) AOML SS funded SeaGlider Observations at 15UTC 10/14/2014: T & S changes during TC Gonzalo T S

10 OMITT Observations available (3) Bond (JISAO) and Cronin (PMEL) KEO mooring During Fengshen, Kammuri and Nuri Fengshen Nuri KEO Water Temperature > -3oC Nuri Fengshen Kammuri Kammuri BP, RH and Tair at 2.5 m; Winds at 4.2 m; LW & SW Rad. at 3.5 m; Rain rate at 3.1 m; Latent Heat Flux (not in RT). KEO Barometric Pressure -35 hpa Fengshen Nuri Kammuri 10

11 Model data available, including WNP Example 1. URI s MPIPOM-TC West Pacific Domain: Ocean Response to Supertyphoon Bolaven with Initialization at NCODA GDEMv3 + GFS SST 23/00Z SST 23/00Z 77.5-m T 23/00Z SST 23/00Z 77.5-m T 28/00Z SST 28/00Z 77.5-m T 28/00Z SST 28/00Z 77.5-m T 22 to 30oC 15 to 29oC OMITT to 30oC 15 to 29oC

12 Model data available, including WNP Example 2. Comparison against daily TMI & AMSRE OI SST OMITT-12 Obs. HYCOM GFS Daily SST for day 1 (left) HYCOM Weaker cooling GFS relatively warm Daily SST for day 5 (right): HYCOM Similar cold wake (~26 o C) and a similar degree of cooling (~4 o C) GFS No change in GFS SST. NO cold wake and no cooling No Mesoscale variability

13 OMITT-13 1D Ideal Case (Preliminary Results): Azimuthal average tangential (contour) and radial wind (shade) at t=96 h uncoupled Axisymmetric wind structure weakens with 1D HYCOM coupled; low level inflow is also weaker Small Storms (50 km) 44 coupled uncoupled Large Storms (150 km) coupled

14 1D Ideal Case: Azimuthal average temperature anomaly at t=96 h OMITT-14 uncoupled Warm core is weaker with 1D HYCOM coupled for slow moving storms; for small and faster moving storms, the difference between uncoupled and coupled forecasts is smaller; Small Storms coupled Large Storms uncoupled coupled

15 OMITT-15 Proposed Assignments (will be update) Hyun-Sook Kim (EMC) (co-chair) George Halliwell (AOML) (co-chair) Joe Cione (HRD) & Eric Uhlhorn (HRD) Air-sea flux parameterizations, evaluation using observations. Assessment of the OM impact on TC forecasts. TC Edouard (2014); TC Isaac (2012); TC Leslie (2011). Ligia Bernardet (DTC) Diagnostic SST cooling and OML response; evaluate using observations. Rerun Real Cases, if necessary. Jili Dong (EMC/AOML) & Lin Zhu (EMC) Ideal studies, w/ and w/o 1D coupling; forecast sensitivity to ocean initialization Assemble and build diagnostic tools. Sue Chen (NRL) & Pete Black (NRL) WNP and EPac case studies; airborne observations for multiple storms Beth Sanabia (USNA) TC Isaac (2012) and TC Sandy (2012). Benjamin Jaimes (U Miami) & Nick Shay (U Miami) Ocean dynamics; evaluation of OM response and OM initialization using airborne observations of multiple storms Isaac Ginis (URI) & BiJu Tomas (URI) Assessment of the OM impact on TC forecasts. Comments and recommendations are solicited by the co-chairs