Seasonal variability of bio-optical and physical properties in the Arabian Sea: October 1994–October 1995

作者：Tommy D. Dickey, John F. Marra, D.E. Sigurdson, Robert A. Weller, Christopher S. Kinkade, Sarah E. Zedler, Jerry D. Wiggert, Chris Langdon · 发表于：Deep Sea Research Part II Topical Studies in Oceanography · 年份：1998 · DOI：10.1016/s0967-0645(98)00061-7 · 被引用次数：115 · 研究领域：Marine and coastal ecosystems、Marine and fisheries research、Marine and coastal plant biology

A mooring instrumented with optical and physical sensors within the upper 300 m was deployed for two consecutive 6-month periods (October 15, 1994 through October 20, 1995; sampling intervals of a few minutes) in the central Arabian Sea (15°30′N, 61°30′E). Both the Northeast Monsoon (November 1, 1994–February 15, 1995) and Southwest Monsoon (June 1– September 15, 1995) were observed. During the NE Monsoon, wind speeds averaged 6 m s-1 and reached up to 15 m s-1 during the SW Monsoon. Intermonsoon periods (Spring February 16–May 31, 1995; and Fall September 16–October 15, 1995) were characterized by weak and variable winds. Shortwave radiation and photosynthetically available radiation (PAR) displayed half-yearly cycles, peaking during the Intermonsoon periods. Two mixed-layer depth definitions have been used to describe our results. The first is based on a temperature difference of 0.1°C of the surface temperature, MLD0.1°C, and the second is based on a difference of 1.0°C, MLD1.0°C. The maximum Winter mixed layer depth (MLD1.0°C∼110 m) was deeper than the Summer mixed layer (MLD1.0°C∼80 m), primarily because of surface cooling and convection. A half-yearly cycle in chlorophyll a was evident with greater values occurring during each Monsoon and into the Intermonsoon periods. High chlorophyll a values associated with cool mesoscale features were also apparent during each Monsoon. These mesoscale features and others have been identified using remotely sensed sea-surface height ...