AOSN-II Harvard Ocean Prediction System (HOPS)
Re-analysis Fields

Results

There are four data files available which contain the gzipped netcdf formatted fields from the HOPS Re-Analysis of the AOSN-II real-time exercise.

Hourly TS has compressed Temperature, Salinity and W at tracer points while the file Hourly UV has compressed horizontal (true east-west and north-south) and vertical velocity at velocity points. These are output at a 1hr frequency on the following flat levels -1, -5, -10, -15, -20, -30, -40, -50, -60, -75, -100, -125, -150, -200, -250, -300, -400, -500, -600, -700, -800, -900, for the duration of the experiment plus a couple of days.

Time sequences of the individual maps have been formed into movies and can be accessed below. Each of the individual daily maps for four representative levels can also be found below.

Domains

A complete description of the HOPS modeling domains for this experiment can be found here.

Initialization/Boundary Conditions

The initialization field was created by an objective analysis of the August 2-6, 2003 Point Sur CTD + WHOI and SIO glider + NPS SST data (thinned for speed).

The initialization fields were created with the following correlation scales

        XZERO  = YZERO  =   37.5   (km)
        XDCAY  = YDCAY  =   15.0   (km) 
        TDCAY  =            10.0   (days)
        XZEROM = YZEROM =  112.5   (km)
        XDCAYM = YDCAYM =   45.0   (km) 
        TDCAYM =          1000.0   (days)
        OADAY  = 12858.0  (06 Aug. 2003 - 0:00:00)

BC(2):  August 21-25, 2003 Point Sur and John Martin CTDs + WHOI and SIO gliders + NPS SST.
        OADAY  = 12875.0  (23 Aug. 2003 - 0:00:00)


BC(3):  September 3-6, 2003 Point Sur CTDs
        OADAY  = 12888.0  (05 Sept. 2003 - 0:00:00)

Initial and boundary estimates of velocity were obtained by geostrophic integration of the mapped T/S fields with an assumed level of no motion of 1250m.

The boundary conditions for temperature and salinity were simply linear interpolations in time of the 3 boundary fields (Aug. 6, Aug. 23, Sept. 5) with persistence after Sept. 5. The boundary conditions for the baroclinic velocity components were Orlanski radiation conditions modified by relaxation to the time interpolated values. The boundary conditions for both transport streamfunction and barotropic vorticity tendency were Orlanski radiation.

Assimilation

Thirty-one assimilation fields were created by objective analyses of August 6 - September 06 2003 Pt. Sur, John Martin and Pt. Lobos CTDs; WHOI and SIO gliders; and NPS aircraft SST with the following correlation scales and analysis dates

        XZERO  = YZERO  =   12.5   (km)
        XDCAY  = YDCAY  =    5.0   (km) 
        TDCAY  =             1.0   (days)
        XZEROM = YZEROM =   50.0   (km)
        XDCAYM = YDCAYM =   25.0   (km) 
        TDCAYM =            80.0   (days)
        OADAY  = 12859.5  (07 Aug. 2003 - 12:00:00)
                           daily through
                 12889.5  (06 Sep 2003 - 12:00:00)

For each analysis, only data within +/- 18 hours of the central analysis time were used. From the mapped temperature and salinity fields, velocity estimates were obtained by geostrophic integration with an assumed level of no motion of 1250m.

For each analysis day, temperature, salinity and baroclinic velocity were assimilated into the reanalysis simulation via optimal interpolation. For each day, the temperature and salinity fields were assimilated 4 times with varying relative weights according to the schedule

          0.33 weight on day x.25
          0.66 weight on day x.375
          0.90 weight on day x.5
          0.33 weight on day x.75

The baroclinic velocity was also assimilated with the same ramping schedule but with weights 1/4 that of the tracers.