Simulated impact of intraseasonal variations in surface heat and momentum fluxes on the pelagic ecosystem of the Arabian Sea

A series of numerical experiments using a three‐dimensional, coupled ecosystem‐circulation model has been performed to evaluate the impact of variations on an “intraseasonal” daily to monthly timescale in surface fluxes of heat and momentum on simulated biological production in the Arabian Sea. The biological component is a four‐compartment, nitrogen‐based system; the physical component is a high‐vertical‐resolution z ‐level model that includes a mixed‐layer model based on the turbulent energy equation and contrasts with layer models which often overestimate vertical mixing associated with intraseasonal mixed‐layer retreat and formation. Experiments show that the intraseasonal variations in the forcing may have to be considered when comparing sparsely sampled data with results from a numerical model. The experiments provide, however, no evidence that there is any rectification impact on longer timescales. In particular, accounting for intraseasonal variations has essentially no effect on the simulated annual mean biological production.