• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.309-323
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• 2020

Estimation of chlorophyll a concentration (CHL) on coastal areas using remote sensing has been mostly performed through multi-spectral satellite image analysis. Recently, various studies using hyperspectral imagery have been attempted. In particular, airborne hyperspectral imagery is composed of hundreds of bands with a narrow band width and high spatial resolution, and thus may be more effective in coastal areas than estimation of CHL through conventional satellite image. In this study, comparative analysis of hyperspectral and satellite-based CHL images was performed to estimate CHL in coastal areas. As a result of analyzing CHL and seawater spectrum data obtained by field survey conducted on the south coast of Korea, the seawater spectrum with high CHL peaked near the wavelength bands of 570 and 680 nm. Using this spectral feature, a new band ratio of 570 / 490 nm for estimating CHL was proposed. Through regression analysis between band ratio and the measured CHL were generated new CHL empirical formula. Validation of new empirical formula using the measured CHL showed valid results, with R² of 0.70, RMSE of 2.43 mg m^-3, and mean bias of 3.46 mg m^-3. As a result of applying the new empirical formula to hyperspectral and satellite images, the average RMSE between hyperspectral imagery and the measured CHL was 0.12 mg m^-3, making it possible to estimate CHL with higher accuracy than multi-spectral satellite images. Through these results, it is expected that it is possible to provide more accurate and precise spatial distribution information of CHL in coastal areas by utilizing hyperspectral imagery.

• Applied Biological Chemistry
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• v.44 no.2
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• pp.73-80
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• 2001

Factors such as temperature $(20,\;60^{\circ}C)$), pH (4.5, 7.0), gaseous phase $(N_2,\;0_2)$, and light (0 lux, 5,000 lux), antioxidants and packaging conditions were investigated to study the effects of above factors on the chlorophyll components in spinach during storage. Regardless of other factors, as the storage temperature increased from $20^{\circ}C$ to $60^{\circ}C$ and pH decreased from 7.0 to 4.5, the contents of chlorophyll a and chlorophyll b in spinach decreased significantly (P<0.05). The amounts of chlorophyll a and chlorophyll b in spinach stored in nitrogen gas were significantly (P<0.05) lower than those in sample in oxygen phase. As the light intensity increased from 0 lux to 5,000 lux during storage, the contents of chlorophyll a and chlorophyll b in spinach significantly (P<0.05) decreased. The antioxidants reduced the degradation of chlorophyll a in a model system during dark storage by minimization of free radical oxidation. The effectiveness of antioxidants decreased as following orders; ${\alpha}-tocopherol$>ascorbic acid>${\beta}-carotene$>catechin>quercetin>rutin>kaempherol>caffeic acid>chlorogenic acid>p-coumaric acid>ferulic acid. The degradation of chlorophyll a in a model system during light storage was minimized by antioxidants due to the reduction of singlet oxygen oxidation. The antidiscoloring potential of antioxidants decreased as following orders; ${\beta}-carotene$>${\alpha}-tocopherol$>ascorbic acid>catechin>quercetin>rutin>kaem-pherol>caffeic acid>chlorogenic acid>p-coumaric acid>ferulic acid. The amounts of chlorophyll a and chlorophyll b in freeze dried spinach packed with polyethylene bag were significantly (P<0.05) lower than those in non-packed freeze dried spinach. The package of spinach in polyethylene bag with the combination of antioxidants could be used to minimize the degradation of chlorophyll components in spinach during storage.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.700-705
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• 2009

Several studies have demonstrated that chlorophyll has many beneficial properties, including anti-inflammatory, anti-tumor, and antioxidant properties. Chlorophyll has been also shown to have an excellent chemopreventive potential against skin tumor. Its preventive mechanism against skin tumor, however, has not been examined in detail. Furthermore, the effects of chlorophyll on UVB-induced cellular responses have not been investigated. Solar UV radiation, in particular its UVB component, is the primary cause of many adverse biological effects, which is responsible for the photoaging and skin cancer. We investigated the preventive effects of chlorophyll a on UVB-mediated responses in human immortalized HaCaT kerationocytes and normal human fibroblast. We found that treatment of chlorophyll a markedly inhibited UVB-induced generation of reactive oxygen species and lipid peroxidation. Chlorophyll a also prevented UVB-induced MMP-1 expression and MMP-2 activation and increased Type I pN collagen synthesis. These results suggest that chlorophyll a is a potent candidate for the prevention and treatment of UVB-induced skin cancer and photoaging.

• Korean Journal of Remote Sensing
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• v.33 no.6_1
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• pp.917-930
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• 2017

To understand the temporal and spatial variations of surface chlorophyll-a concentration (Chl-a) distribution in the Indian Ocean ($30^{\circ}E{\sim}120^{\circ}E$, $30^{\circ}S{\sim}30^{\circ}N$) by the Indian Ocean Dipole (IOD), we conducted EOF and K means analyses of monthly satellite-derived Chl-a data in the region during 1998~2016 periods. Chl-a showed low values in the central region of the Indian Ocean and relatively high values in the upwelling region and around the marginal regions of the Indian Ocean. It also had a strong seasonal variation of Chl-a, showing the lowest value in the spring and the highest value in summer due to the change of the monsoon and current system. The EOF analysis showed that Chl-a variation in EOF mode 1 is related to ENSO (El $Ni{\tilde{n}}o$/Southern Oscillation) and that of mode 2 is linked to IOD. Both modes explained spatially opposite trends of Chl-a in the east and west Indian Ocean. From K means analysis, the Chl-a variation in the east and west Indian Ocean, and around India have relatively good relationship with IOD while that in the tropical and middle Indian Ocean closely associated with ENSO. The spatial and temporal distribution of Chl-a also showed distinct spatial and temporal variations depend on the different types of IOD events. IOD classifies two patterns, which occurred during the developing ENSO (First Type IOD) and the year following ENSO event (Second Type IOD). Chl-a variation in the First Type IOD started in summer and peaked in fall around the east and west Indian Ocean. Chl-a variation in the Second Type IOD occurred started in spring, peaked in summer and fall, and disappeared in winter. In the Chl-a variation related to IOD, developing process appearing in the Chl-a difference between the east and west Indian ocean was similar. Chl-a variation in the northern Indian Ocean were opposite trend with changing developing phase of IOD.

• Korean journal of food and cookery science
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• v.21 no.3 s.87
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• pp.339-345
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• 2005

This study was carried out to determine the changes of chlorophyll contents in spinach during growth stages and storage with two packaging materials. The chlorophyll contents increased to a maximum level in the spinach leaves after 35 days of planting, while the level in the roots extremely decreased and that in the stems did not change during the growth period. The total chlorophyll content was higher in the leaves than that in the stems and roots. The ratios of chlorophyll a/b in the leaves and stems were almost similar to those reported for spinach elsewhere. When stored for 1, 3, and 5 days without packaging, the remaining percentage of chlorophyll was $96.29\%,\;90.79\%\;and\;85.74\%$, respectively, at $5^{\circ}C,\;and\;82.75,\;44.63,\;33.07\%$, respectively, at $20^{\circ}C$. The chlorophyll contents of the spinach stored in polyethylene bags were significantly higher than of that those without packaging and of that packaged with newspaper during storage. From the results, it was found that spinach packaged in polyethylene bags suppressed the degradation of chlorophyll and maintained the freshness during low temperature storage and that the chlorophyll contents increased during the growth period.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.6
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• pp.586-592
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• 2003

This research used High Performance Liquid Chromatography(HPLC) to analyze and compare the content and the pattern of chlorophyll to find the difference in quality, water temperature, and the stirring time between the three different types of Korean and Japanese powder green tea, which were currently on the market. Chlorophyll contents of Japanese-made medium quality tea (S5: 8.34mg/g), and low quality tea (S6: 8.23mg/g) were relatively high, and that of Korean-made medium quality tea (S2 ; 4.87mg/g) was lower. The water temperature of 85$^{\circ}C$ and 95$^{\circ}C$ were high except in Korean-made medium and low quality powder green tea (S2 and S3). Japanese-made powder tea required 60 seconds of stirring time and Korean-made tea required 15 seconds, but 30 seconds seem to be the ideal stirring time for both of them. Chlorophyll a, b, pheophytin a, b, and pheophorbide were confirmed from the chlorophyll pattern. There were 1.5∼2 times more of chlorophyll a in Japanese-made one compared to that of Korean-made one; also 1.5∼2 times more of pheophytin a in Korean-made one than Japanese-made one. It might be concluded that Japanese-made powder green tea was higher in quality.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.63-66
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• 1985

Phytoplankton (microplankton and nannoplankton) biomass as chlorophyll-a concentrations ana ratios of nannoplanktons ($size<60{\mu}m$) to total phytoplanktons ($size<300{\mu}m$) were measured in the coastal waters of Korea in fall, 1983. Chlorophyll-a concentrations of total phytoplankton ranged from 0.202 to 1.350 $mg/m^3$ with a mean and standard deviation, $0.597{\pm}0.287\;mg/m^3$, Chlorophyll-a concentrations of the nannoplankton ranged from 0.100 to $0.855\;mg/m^3$ with a mean and standard deviation, $0.372{\pm}0.201\;mg/m^3$, and it accounted for 25.4 to $83.3\%$ with an average $62.2\%$ to total phytoplankton biomass as chlorophyll-a concentrations. The amounts of chlorophyll-a concentrations of total phytoplankton in the water column below the surface area of $1m^2$ varied from 16.12 to $17.67\;mg/m^2$ with a mean $17.01\;mg/m^2$.

• Korean Journal of Remote Sensing
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• v.18 no.4
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• pp.187-199
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• 2002

Correlation between chlorophyll a in the East China Sea and spectral bands (412, 443, 490, (510), 555, (676, 765)nm) of Ocean Scanning Multi-Spectral Imager (OSMI) including the profile multi-spectral radiometer (PRR-800) was studied. The values of remote sensing reflectance (Rrs) at the bands corresponding to the field chlorophyll $\alpha$ in the East China Sea were much higher than those in clear waters off California, USA. In case of the particle absorptions related to the chlorophyll a concentration at the spectral bands (440, 670nm) were much higher in the East China Sea than the ones in the clean waters off California. The normalized water leaving radiances (nLw) at 412, 443, 490, 555 nm of OSMI and the field chlorophyll a in the East China Sea were correlated each other. According to the results, the relationship between field chlorophyll $\alpha$ and nLw 410 nm in OSMI bands was the lowest, whereas that between field chlorophyll a and nLw 555 nm in the bands was the highest. Reciprocal action between the field chlorophyll a and the band ratio of the OSMI bands (nLw410/nLw555, nLw443/nLw555, nLw490/nLw555) was also studied. Relationship between the chlorophyll $\alpha$ and the band ratio (nLw490/nLw555) was highest in the OSMI bands. Relationship between the chlorophyll $\alpha$ and the ratio (nLw490/nLw555) was higher than one in the nLw410/nLw555. The difference in the estimated chlorophyll $\alpha$ (mg/m$^3$) between OSMI and SeaWiFS (Sea Viewing Wide Field-of-View Sensor) at the special observing stations in the northern eastern sea of Jeju Island in February 25, 2002 was about less than 0.3 mg/m$^3$ within 3 hours. It is suggested that OC2 (ocean color chlorophyll 2 algorithm) be used to get much better estimation of chlorophyll $\alpha$ from OSMI than the ones from the updated algorithms as OC4.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.417-424
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• 1990

Effect of physical processes on the surface distributions of chlorophyll-a and nutrients was investigated in the southern sea of Korea during summer season. The northwestern area of Cheju Island had higher concentrations of the chlorophyll-a and nutrients than its southeastern area. A nutrient-rich patch was observed in the western area of Cheju Island and the northern area of $34^{\circ}N$ respectively. It seems that the patch in the western area of Cheju Island is formed by horizontal extension of the low-saline Coastal Water of China Contiental(CWCC), while the patch in the northern area of $34^{\circ}N$ by vertical mixing. Also, the high chlorophyll-a in the vicinity of Cheju Island appears to be ascribed to sufficient supply of nutrient from bottom water by coastal upwelling.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.35-45
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• 1996

The reflectance of chlorophyll was measured using UV-VIS spectrophotometer with the reflectance integrator in the laboratory in order to define its spectral characteristics. Sharp peaks appear at around 485nm and 655nm due to fluorescence and scattering, and the reflectance of chlorophyll increases at 580nm. With the increase in the chlorophyll concentration, the reflectance also increases. We have applied TM data to the reflectance spectrum of chlorophyll and have developed two formula with which one can estimate the chlorophyll concetration. Satellite re sensing, with its synoptic overage, is used to obtain the chlorophyll concentration in Daecheong reservoir. The approach involved acquisition of water quality samples front boat simultaneous with Landsat 5 satellite overpass. The remotely-sensed data and the ground truth data were obtained oil 20 June 1995 and on 18 March 1996. Regression models have been developed between the chlorophyll concentration and Landsat Thematic Mapper digital data. As the regression model was determined based on the correlation coefficient which was higher than 0.7 and the spectral characteristics of chlorophyll, and we have applied it to the entire study area to genelate a distribution map of trophic state. According to the trophic state map made based upon Aizaki's TSI and chlorophyll a concentration, the area where Okchun stream was flowing into was shown to be polluted the most all over the Daechung reservoir by showing an eutrophic state in June 1995 and a mesotrophic state in March 1996.