Arabian Sea Model Results

Investigators Raleigh Hood
Julian McCreary
Kevin Kohler
Sharon Smith
Don Olson

Co-Investigators none

SMP Project Development, validation and improvement of a coupled biological/chemical/physical model for the Arabian Sea

Product Arabian Sea ecosystem model results (NetCDF)

Description A coupled physical-biological model was used to synthesize observations from cruises and time-series data generated during the U.S. JGOFS Arabian Sea Process Study. The physical component, a variable-density, 4 1/2 layer model, consists of four active layers above the deepest 1/2 layer in which pressure gradients are assumed to vanish. Each layer (reported as 'model level' in the results) represents either a specific water-mass type or dynamically important region: layer 1, surface mixed layer; layer 2, diurnal thermocline; layer 3, seasonal thermocline and layer 4, main thermocline. Level height, reported in meters, represents the depth layer interface, i.e., h1 is the depth of the interface between layer 1 and layer 2. The biological component comprises a set of advective-diffusive equations in each layer to determine nitrogen concentration in four compartments: nutrients, phytoplankton, zooplankton and detritus. In each run, the physical model is spun up from a state of rest for a period of five years, after which the coupled system is integrated from April 15, 1993 through December 26, 1995. The model was adjusted and improved through analysis of iterative runs and model-data comparison.

Reported fields from the four-dimensional coupled physical-biological model of the Arabian Sea include:

Grid Variables:
  • LONGITUDE = longitude (degrees East)
  • LATITUDE = latitude (degrees North)
  • LEVEL = model level
  • TIME = time (days) since the start of the model run (01-JAN-1993)
  • HEIGHT = Level Height (meters)
  • TEMPERATURE = Temperature (degrees Celsius)
  • SALINITY = Salinity (ppt)
  • DIN = Dissolved Inorganic Nitrogen (umol kg-1)
  • PHYTOPLANKTON= Phytoplankton Biomass, Nitrogen (umol kg-1)
  • ZOOPLANKTON= Zooplankton Biomass, Nitrogen (umol kg-1)
  • DETRITUS= Detritus, Nitrogen (umol kg-1)

Anyone wishing to access other parts of the model solution should contact Dr. Hood directly at the address listed below. Additional information may be available online from sites authored by the principal investigators.

  inputs and model code (site maintained by Kevin Kohler)

Submitted March 2003

e-Citation R.R. Hood, J.P. McCreary, K.E. Kohler, S.L. Smith and D.B. Olson. U.S. JGOFS Synthesis & Modeling Project - Results. U.S. JGOFS. iPub: March 2003. 'date you accessed the data'

References R.R. Hood, K.E. Kohler, J.P. McCreary and S.L. Smith. 2003. A four-dimensional validation of a coupled physical biological model of the Arabian Sea. Deep-Sea Research II 50(22-26) 2917-2945, doi:10.1016/j.dsr2.2003.07.004, U.S. JGOFS Contribution No. 939.

McCreary, J.P., Jr., K.E. Kohler, R.R. Hood, and D.B. Olson. 1996. A four-component ecosystem model of biological activity in the Arabian Sea. Progress in Oceanography 37 193-240.

McCreary, J.P., Jr., K.E. Kohler, R.R. Hood, S. Smith, J. Kindle, A.S. Fischer and R.A. Weller (2001). Influences of diurnal and intraseasonal forcing on mixed-layer and biological variability in the Central Arabian Sea. Journal of Geophysical Research, 106: 7139-7155, U.S. JGOFS Contribution No. 586.

Contact Raleigh R. Hood
Horn Point Environmental Laboratory
2020 Horns Point Rd
P.O. Box 775
Cambridge, MD 21613
tel: (410) 221-8434, 8497
fax: (410) 221-8490