A QUASI-GLOBAL CONFIGURATION OF ROMS (OR, TOWARDS GOMS?) Guillermo Auad & Art Miller (CRD/SIO) Grid features : ● zonal resolution: 0.8º (fixed); meridional resolution: 0.3 to 0.7º (slowing varying: ∆ resolution < 1.5%); vertical resolution: 20 levels. ● Includes: fixed Iceshelf, topography from etopo2. ● Zonal walls at 80º (N & S). ● E-W periodic condition used at longitude 180º. Runs carried out so far: 1.- Spin up climatological run from rest and Levitus T-S. (60-year long) driven by NCEP/NCAR reanalysis wind stresses and heat fluxes year long hindcast run (i.e., climat. + anomalous winds and heat fluxes), from 1948 to 2003 (finished a few days ago).

Organization A minor code adaptation Spin up of the model's total kinetic energy Model output: main ocean currents of the World A tough test: coastal flows A tougher test: representation of a water mass: NPIW 2 climatic indexes in the Pacific Ocean: PDO and Nino3.4 Planned applications

Scaling of horizontal viscosity coefficient goal: for each grid cell to proportionally (to its grid size) contribute potential vorticity to western boundary layers. ß ψ x ~ A h ψ xxxx (1) but since A h needs to satisfy a minimum value in order to yield realistic solutions (Bryan, Manabe and Pacanowski, 1975): A h > 0.17 * ß* dx³ (2) from (1) and (2) we can scale A h as A h ~ A h0 (dx/dx 0 )**3 cos(φ)cos(φ 0 ) (3) where the subindex 0 marks the latitude, and viscosity of the largest grid size in the domain (dx 0 ). In practice: Obtain A h0 from (2) (i.e., for the largest grid size), and then obtain the rest using (3).

Minimum Viscosity Coeff. (visc2) vs. Latitude A h =A h ( φ,dx)

MODEL's TOTAL KINETIC ENERGY vs. TIME

ROMS MGSVA Gulf Stream, Antilles Curr., Loop Current & Labrador Curr.

Kuroshio, Oyashio, Liman, Tsuchiya & Tsugaru Currents

from MGSVA Malvinas-Brasil Confluence Area summer winter

TROPICAL PACIFIC CURRENTS AND SST

Tropical Instability Waves

Across-equator zonal velocity profiles (152 °W – Hawaii-Tahiti transect) From Johnson & Luther (1994) - current meter data ROMS

150 m Surface Winter Flows off California

STRAIT OF GIBRALTAR Mean speed from ROMS Mean speed from obs (ADCP)

Guinea, Equatorial and Angola Currents MGVSA

TRANSPORT THROUGH DRAKE PASSAGE Malvinas Whitworth & Peterson (1985)(*)=134  13 Sv Various ACDP estimates from the Univ. of Southampton=94Sv-155Sv ROMS : 128 Sv

ANTARCTIC CIRCUMPOLAR CURRENT

(from L. Talley, SIO) Global Salinity Minimum Global ROMS

SEA LEVEL COMPARISON AT SAN FRANCISCO

CLIMATIC INDEXES FROM 56-y RUN: PDO and NI ÑO3.4 Corr=0.67; Coherence for 25y harmonic: 0.91 (10 ° phase) Corr=0.73; Coherence for 4y harmonic=0.78 (ampl=0.7 & phase =7 °)

Planned Applications of the Global ROMS Couple “GOMS” to an atmospheric model (ECPC fcsts) Use its output (climat & hincdast) as OBCs in regional models (a few latin american scientists are interested in this) Sea level (*)& climatic studies. Studies on water mass formation (NPIW and Ross Sea area) Future runs/planned improvements: Filter forcing with Killworth's matrix to obtain more realistic amplitudes (*) (e.g., Nino3.4 index). Include sea-ice. (*) underway