Banse,K.,English,D.C.
Geographical differences in seasonality of CZCS-derived phytoplankton pigment in the Arabian Sea for 1978-1986 Journal Article
In: Deep-Sea Research Part II, vol. 47, no. 322, pp. 1623-1677, 2000.
Abstract | BibTeX | Tags: Arabian Sea, chlorophyll, depth, Gulf of Oman, lead, Oman, plankton, productivity, timing, trap, Upwelling
@article{,
title = {Geographical differences in seasonality of CZCS-derived phytoplankton pigment in the Arabian Sea for 1978-1986},
author = {Banse,K.,English,D.C.},
year = {2000},
date = {2000-01-01},
journal = {Deep-Sea Research Part II},
volume = {47},
number = {322},
pages = {1623-1677},
abstract = {In situ measurements of phytoplankton chlorophyll in the Arabian Sea were taken largely along temporally and spatially unevenly distributed sections, scarce especially prior to the operation of NASA's Coastal Zone Color Scanner (CZCS). Herein, the CZCS pigment observations between late 1978 and mid-1986 north of 10§N, including the outer Gulf of Oman, are depicted for 14 subregions beyond the continental shelves as daily means, often only five days apart. To eliminate bias from electronic overshoot, the data were reprocessed with a more conservative cloud screen than used for NASA's Global Data Set. The pattern, derived from the older in situ observations, of one period with elevated chlorophyll almost everywhere during the Southwest Monsoon (SWM) and one additional late-winter bloom in the north, is confirmed. The differing nitrate silicate ratios in freshly entrained water in the central and northern Arabian Sea seem to lead to different succession and perhaps to differing vertical fluxes, and during winter favor blooms only in the north. The spatial pigment pattern in the outer Gulf of Oman is not an extension of that of the northwestern Arabian Sea. The seasonal physical forcing explains much of the timing of pigment concentration changes, but not the levels maintained over long periods. From the CZCS observations it is unclear whether the period of high phytoplankton productivity expected during the SWM in the open Arabian Sea lasts for about two or four months. During this entire season, chlorophyll values in the upper layers rarely exceed 1-2 mg m-3 outside the zone influenced by the Arabian upwelling. Near 15§N, however, fluxes into sediment traps at 3 km depth indicate an onset of high primary production very soon after the arrival of the SWM and suggest a long period of high production in the open sea. The partial temporal disconnect during the SWM between pigment changes in the upper part of the euphotic zone and of fluxes into the traps is disconcerting. For future modeling of plankton production in the open Arabian Sea, the use of two size classes of phytoplankton is recommended. The utility of satellite-derived pigment concentrations (as opposed to temporal changes of pigment) for testing such models is questioned.},
keywords = {Arabian Sea, chlorophyll, depth, Gulf of Oman, lead, Oman, plankton, productivity, timing, trap, Upwelling},
pubstate = {published},
tppubtype = {article}
}
In situ measurements of phytoplankton chlorophyll in the Arabian Sea were taken largely along temporally and spatially unevenly distributed sections, scarce especially prior to the operation of NASA's Coastal Zone Color Scanner (CZCS). Herein, the CZCS pigment observations between late 1978 and mid-1986 north of 10§N, including the outer Gulf of Oman, are depicted for 14 subregions beyond the continental shelves as daily means, often only five days apart. To eliminate bias from electronic overshoot, the data were reprocessed with a more conservative cloud screen than used for NASA's Global Data Set. The pattern, derived from the older in situ observations, of one period with elevated chlorophyll almost everywhere during the Southwest Monsoon (SWM) and one additional late-winter bloom in the north, is confirmed. The differing nitrate silicate ratios in freshly entrained water in the central and northern Arabian Sea seem to lead to different succession and perhaps to differing vertical fluxes, and during winter favor blooms only in the north. The spatial pigment pattern in the outer Gulf of Oman is not an extension of that of the northwestern Arabian Sea. The seasonal physical forcing explains much of the timing of pigment concentration changes, but not the levels maintained over long periods. From the CZCS observations it is unclear whether the period of high phytoplankton productivity expected during the SWM in the open Arabian Sea lasts for about two or four months. During this entire season, chlorophyll values in the upper layers rarely exceed 1-2 mg m-3 outside the zone influenced by the Arabian upwelling. Near 15§N, however, fluxes into sediment traps at 3 km depth indicate an onset of high primary production very soon after the arrival of the SWM and suggest a long period of high production in the open sea. The partial temporal disconnect during the SWM between pigment changes in the upper part of the euphotic zone and of fluxes into the traps is disconcerting. For future modeling of plankton production in the open Arabian Sea, the use of two size classes of phytoplankton is recommended. The utility of satellite-derived pigment concentrations (as opposed to temporal changes of pigment) for testing such models is questioned.
Bartolacci,D.M.,Luther,M.E.
Patterns of co-variability between physical and biological parameters in the Arabian Sea Journal Article
In: Deep-Sea Research Part II, vol. 46, no. 40, pp. 1933-1964, 1999.
Abstract | BibTeX | Tags: Arabian Sea, timing, Upwelling
@article{,
title = {Patterns of co-variability between physical and biological parameters in the Arabian Sea},
author = {Bartolacci,D.M.,Luther,M.E.},
year = {1999},
date = {1999-01-01},
journal = {Deep-Sea Research Part II},
volume = {46},
number = {40},
pages = {1933-1964},
abstract = {The relationship between physical forcing and biological response observed in the Arabian Sea for the years 1978-1986 were examined. Spatial and temporal patterns of variability in a climatological time-series of three possible physical forcing parameters and CZCS-derived phytoplankton pigment concentration during the annual cycle were quantified using single and joint empirical orthogonal function (EOF) and singular-value decomposition (SVD) analyses. Monthly composites of the NASA regional pigment data were interpolated to fill data voids and binned corresponding to the physical flux data. Nearly all the spatial-temporal analyses consistently partitioned a large portion of the variability using only 1 or 2 dominant modes and indicated a lag in the timing of the peak pigment concentration behind the maxima in physical forcing. In all cases, major modes of variability resembled the Southwest Monsoon pattern, with the Northeast Monsoon contributing very little to the total variance and covariance. The Joint EOF and SVD analyses incorporated subtle features surrounding the peak Southwest Monsoon phenomena. Correlation maps of the joint EOF analysis depicted differences in spatial variability of pigment concentration associated with stress and curl, showing areas of curl-driven upwelling distinct from coastal upwelling, with possible off-shore advection of the curl-induced high pigment waters.},
keywords = {Arabian Sea, timing, Upwelling},
pubstate = {published},
tppubtype = {article}
}
The relationship between physical forcing and biological response observed in the Arabian Sea for the years 1978-1986 were examined. Spatial and temporal patterns of variability in a climatological time-series of three possible physical forcing parameters and CZCS-derived phytoplankton pigment concentration during the annual cycle were quantified using single and joint empirical orthogonal function (EOF) and singular-value decomposition (SVD) analyses. Monthly composites of the NASA regional pigment data were interpolated to fill data voids and binned corresponding to the physical flux data. Nearly all the spatial-temporal analyses consistently partitioned a large portion of the variability using only 1 or 2 dominant modes and indicated a lag in the timing of the peak pigment concentration behind the maxima in physical forcing. In all cases, major modes of variability resembled the Southwest Monsoon pattern, with the Northeast Monsoon contributing very little to the total variance and covariance. The Joint EOF and SVD analyses incorporated subtle features surrounding the peak Southwest Monsoon phenomena. Correlation maps of the joint EOF analysis depicted differences in spatial variability of pigment concentration associated with stress and curl, showing areas of curl-driven upwelling distinct from coastal upwelling, with possible off-shore advection of the curl-induced high pigment waters.