3D T/S, geostrophic horizontal and quasi-geostrophic vertical velocity fields
This page provides access to the T/S, horizontal geostrophic velocity fields and quasi-geostrophic vertical velocity fields reconstructed from the omega BIO-hesperides cruise. The resulting 3D analysed fields (temperature, salinity and velocity) are stored as 3D matrices.(up to Table of Contents)
2. Analysed Data Fields
There are three consecutive survey from the BIO Hesperides Cruise:
The T,S fields were computed by a variational inverse method and calibrated by a cross-validation procedure. The geostrophic velocities were obtained by integrating the thermal wind equation with a reference level of 200m, and adding a non-divergent stream function computed from ADCP data at that level. The vertical velocities were computed from the quasi-geostrophic omega formulation.
Units are 'psu' for salinity, 'degree Celsius' for temperature and 'm/s' for horizontal geostrophic velocity. Vertical velocity unit is m/day.
To get pseudo-synoptic analysed fields, several methods have been developped and implemented
3. Format description
To understand the way the data is stored, please refer to the figure below. The file are stored in a 3D array (matrix) with 3 indexes I, J, K, going from 1 to IMAX, 1 to JMAX, 1 to KMAX. The origin is located at the 'bottom left deepest corner'.
There are KMAX horizontal slices from the bottom (K=1) to the surface (K=KMAX). Increasing I's go from W to E and increasing J's go from S to N.
The point (i,j,k) is located at (-5.0 + i*0.03 , i=0,43) long , (35.7 + j*0.025 , j=0,28) lat and (-301+k*8, k=0,37) m depth except for vertical velocities where point (i,j,k) is located at (-4.94 + i*0.03 , i=0,39) long , (35.75 + j*0.025 , j=0,24) lat and (-301+k*8, k=0,37) m depth.
Extracting routine written in FORTRAN :
C ---------------------------------------- SUBROUTINE READIT (A,IMAX,JMAX,KMAX) C ---------------------------------------- REAL*4 A(IMAX,JMAX,KMAX) INTEGER IMAX,JMAX,KMAX DO 10 K = 1,KMAX DO 20 J = 1,JMAX READ (10,101) (A(I,J,K),I=1,IMAX) 20 CONTINUE 10 CONTINUE 101 FORMAT (5E12.5) END(up to Table of Contents)
4. Access to the 3D analysed fieldsTo download the files, put a '.Z' after the file name. Uncompress the files with 'uncompress < filename >'.
5. Access to the jpg images
Last modified October 26, 1998
Send comments to M.Rixen@ulg.ac.be