NUMERICAL SIMULATIONS OF THE ARABIAN SEA USING TRACERS AS PROXIES FORPHYTOPLANKTON BIOMASS

Citation
Pc. Gallacher et Pa. Rochford, NUMERICAL SIMULATIONS OF THE ARABIAN SEA USING TRACERS AS PROXIES FORPHYTOPLANKTON BIOMASS, J GEO RES-O, 100(C9), 1995, pp. 18565-18579
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oceanografhy
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
ISSN journal
2169-9275 → ACNP
Volume
100
Issue
C9
Year of publication
1995
Pages
18565 - 18579
Database
ISI
SICI code
2169-9275(1995)100:C9<18565:NSOTAS>2.0.ZU;2-X
Abstract
A set of numerical simulations were conducted to determine the potenti al interannual variation of phytoplankton biomass in the Arabian Sea. A four-layer, reduced gravity model was forced with interannually vary ing, monthly mean winds for the years 1981 to 1990 and a seasonally va rying, monthly mean climatological heat flux. Passive tracers, with fi xed source and decay rates, were used as proxies for phytoplankton. Th e tracers were released in the second layer, and upwelling combined wi th interlayer mixing transported the tracers into the first (the top) layer of the model. In the top layer advection, diffusion and specifie d decay rate produced distributions of tracer concentration that we co mpare with coastal zone color scanner (CZCS) images. In addition to ma ps of tracer distribution, we constructed time series from areal avera ges of tracer concentration. The time series are particularly useful f or analyzing the temporal variability of the tracer concentrations. Th ere was substantial interannual variability in the results and a stron g seasonal signal associated with the southwest monsoon. The years of maximal tracer concentration were 1990 and 1985. The first was associa ted with a decadal maximum in wind speed and the second with a large w ind stress curl over the western Arabian Sea. The years with minimal t racer concentration were 1981 through 1983. We compare our results wit h published analyses of composited CZCS images during the southwest mo nsoon in 1981 and 1982. We find general agreement between our results and the CZCS images during the peak of the southwest monsoon; however, we find that during the early phase of the monsoon, when the winds ar e strengthening rapidly with time, the CZCS images are badly aliased b y year to year changes in the time periods used to composite available satellite data.