DSpace Collection:

Seasonal and Summer Interannual Variations of SeaWiFS Chlorophyll a in the Yellow Sea and East China Sea

2012-01-01T00:00:00Z

Title: Seasonal and Summer Interannual Variations of SeaWiFS Chlorophyll a in the Yellow Sea and East China Sea Authors: Kim, Hyun-cheol; K Okamura; J Ishizaka; Y Kiyomoto; S W Kim; Y B Son; H Yamaguchi Abstract: Seasonal variability in satellite chlorophyll a concentrations (SCHL) in the Yellow Sea and the East China Sea (YECS) was investigated using 10-year averages of monthly data collected between September 1997 and October 2006. Interannual variations were also assessed to help clarify the influence of Changjiang River discharge (CRD) during summer. The YECS was represented by 12 areas each with different seasonal variability in SCHL. SCHL were overestimated during winter due to resuspension of sediment near the Changjiang Bank and near coastal areas. Increases of SCHL were observed over large areas of the YECS during spring, as would be expected with the occurrence of spring blooms. The spatial distribution of the summer maximum of SCHL shifted from the Changjiang River mouth to just east of Jeju Island from July to September. An eastward shift of the high SCHL water coincided with the movement of the Changjiang diluted water (CDW), taking approximately 2 months to move from Changjiang River mouth to Jeju Island. Summer SCHL between 1998 and 2006 in this region were positively correlated with CRD with a time lag of 0？2 months, suggesting that the interannual variation of SCHL was controlled by the interannual variation of CRD. SCHL during summer in the Yellow Sea gradually increased over the 10 years, indicating possible eutrophication. variations were also assessed to help clarify the influence of Changjiang River discharge (CRD) during summer. The YECS was represented by 12 areas each with different seasonal variability in SCHL. SCHL were overestimated during winter due to resuspension of sediment near the Changjiang Bank and near coastal areas. Increases of SCHL were observed over large areas of the YECS during spring, as would be expected with the occurrence of spring blooms. The spatial distribution of the summer maximum of SCHL shifted from the Changjiang River mouth to just east of Jeju Island from July to September. An eastward shift of the high SCHL

한국연안해역의 플랑크톤생태학(동해의 일차생산력)

2011-01-01T00:00:00Z

Title: 한국연안해역의 플랑크톤생태학(동해의 일차생산력) Authors: 유신재; Kim, Hyun-cheol

Spring Bloom and mixed layer depth in the JES

2009-01-01T00:00:00Z

Title: Spring Bloom and mixed layer depth in the JES Authors: Kim, Hyun-cheol; Yoo, Sinjae; Jang, chan Joo; Kim, Eun Jin Abstract: Climate changes are currently observed at a global scale. In order to give better estimates of the future change, understand of past is important. Marine ecosystem is observed due to its role in climate, such as phytoplankton takes an important role in carbon cycle over world as reducer of CO2. Phytoplankton is sensitively responses to climate change due to they are primary producer of marine ecosystem. In this study, to assess the response on climate change, the seasonal dynamics of phytoplankton bloom in the Japan/East Sea is studied that a pronounced year-to-year variation over past 12 years as was observed from SeaWiFS (1997-recent) and MODIS/AQUA (2002~recent). As some researches reported, the seasonal dynamics shows a typical bimodal cycle such as spring bloom and fall bloom. However, the seasonality showed a strong year-to-year variation. Gaussian fitting is used to define the spring bloom as a index of interannual variation. Usually, spring bloom occurred in March, however the area where bloom occurred in March showed a dramatic year-to-year variation. The area of March bloom in 2003 showed the largest, while the area in 2000 showed the smallest. Especially, in 2006 the largest May bloom (late bloom) in north JES was occurred. To explain the interannual variations, we assessed the mixed layer depth (MLD) from ARGO and Sea-Ice of north JES. In critical depth theory, the MLD is import parameter of spring bloom. But get the MLD is not easy due to it from in situ observing. Using ARGO we calculated the MLD and accesses a role of it to spring bloom.

Distribution of Changjiang Diluted Water Detected by Satellite Chlorophyll-a and Its Interannual Variation during 1998-2007

2008-01-01T00:00:00Z

Title: Distribution of Changjiang Diluted Water Detected by Satellite Chlorophyll-a and Its Interannual Variation during 1998-2007 Authors: S. Yoo; K. Tanaka; J. Ishizaka; Y. Kiyomoto; H. Yamaguchi; Kim, Hyun-cheol; I. Oh; T. Park; S. Kim; K. Okamura; J. Zhu Abstract: Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll-a distribution in summer in the East China Sea during 1998？2007 was analyzed. Statistical analysis with K-means clustering technique allowed us to define the proper satellite chlorophyll-a concentration indicating the Changjiang Diluted Water (CDW). The spatial distributions of the higher satellite chlorophyll-a concentrations (>0.48 mg m？3) corresponded well with the distributions of lower salinity CDW (<30？32) every year. Interannual variation of the CDW area, indicated by the high satellite chlorophyll-a, correlated with the interannual variation of the Changjiang summer freshwater discharge. The correlation analysis indicated that the CDW spread eastward in the East China Sea with a time lag of 1 to 2 months after the discharge.