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Masanobu Shimada Hiromi Oaku Yasushi Mitomi Hiroshi Murakami Akira Mukaida Yasuhisa Nakamura Joji Ishizaka Hiroshi Kawamura Tasuku Tanaka Motoaki Kishino Hajime Fukushima 《Journal of Oceanography》1998,54(5):401-416
We present calibration and validation results of the OCTS’s ocean color version-3 product, which mainly consists of the chlorophyll-a concentration (Chl-a) and the normalized water-leaving radiance (nLw). First, OCTS was calibrated for the inter-detector sensitivity difference, offset, and absolute sensitivity using external
calibration source. It was also vicariously calibrated using in-situ measurements for water (Chl-a andnLw) and atmosphere (optical thickness), which were acquired synchronously with OCTS under cloud-free conditions. Second, the
product was validated using selected 17 in-situ Chl-a and 11 in-situnLw measurements. We confirmed that Chl-a was estimated with an accuracy of 68% for Chl-a less than 2 mg/m3, andnLw from 94% (band 2) to 128% (band 4). Geometric accuracy was improved to 1.3 km. Stripes were significantly reduced by modifying
the detector normalization factor as a function of input radiance. 相似文献
2.
Hajime Fukushima Akiko Higurashi Yasushi Mitomi Teruyuki Nakajima Toshimitsu Noguchi Toshio Tanaka Mitsuhiro Toratani 《Journal of Oceanography》1998,54(5):417-430
This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic
structure with Gordon and Wang’s Sea WiFS algorithm, it uses 10 candidate aerosol models including the “Asian dust model”
introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670
and 865 nm bands, the algorithm selects a pair of aerosol models that account best for the observed spectral reflectances,
and synthesizes the aerosol reflectance used for the atmospheric correction. Two different schemes for determining the value
of the parameter for the aerosol model selection are presented and their anticipated estimation error is analyzed in terms
of retrieved water reflectance at 443 nm. The results of our numerical simulation show that the standard deviation of the
estimation error of the “weighted average” scheme is mostly within the permissible level of ±0.002, reducing the error by
18% on average compared to the “simple average” scheme. The paper further discusses the expected error under the old CZCS-type
atmospheric correction, which assumes constant aerosol optical properties throughout the given image. Although our algorithm
has a better performance than the CZCS algorithm, further analysis shows that the error induced by the assumption taken in
the algorithm that the water-leaving radiance at 670 nm band is negligibly small may be large in high pigment concentration
waters, indicating the necessity for future improvements. 相似文献
3.
Hiroshi Kawamura 《Journal of Oceanography》1998,54(5):383-399
The Ocean Color and Temperature Scanner (OCTS) on board the Advanced Earth Observing Satellite (ADEOS) observed the chlorophyll-a concentration in the surface layer and sea surface temperature in global oceans from October 1996 to June 1997. The OCTS
team was formed in the National Space Development Agency of Japan (NASDA) Earth Observation Research Center (EORC) to develop
algorithm, calibrate and validate OCTS products and promote OCTS data usage. Intensive efforts to improve the quality of the
OCTS products were made after the launch of ADEOS. Much sea-truth data was collected, and the algorithms to retrieve the ocean
parameters have been revised several times. The OCTS data were distributed to the user community through the Internet while
OCTS was functioning. An overview of the OCTS mission is presented in this paper.
The OCTS Team is formed by NASDA personnel and supporting scientists listed in Appendix 1. 相似文献
4.
Akihiko Tanaka Motoaki Kishino Roland Doerffer Helmut Schiller Tomohiko Oishi Tadashi Kubota 《Journal of Oceanography》2004,60(3):519-530
An algorithm is presented to retrieve the concentrations of chlorophyll a, suspended pariclulate matter and yellow substance
from normalized water-leaving radiances of the Ocean Color and Temperature Sensor (OCTS) of the Advanced Earth Observing Satellite
(ADEOS). It is based on a neural network (NN) algorithm, which is used for the rapid inversion of a radiative transfer procedure
with the goal of retrieving not only the concentrations of chlorophyll a but also the two other components that determine the water-leaving radiance spectrum. The NN algorithm was tested using the
NASA's SeaBAM (SeaWiFS Bio-Optical Mini-Workshop) test data set and applied to ADEOS/OCTS data of the Northwest Pacific in
the region off Sanriku, Japan. The root-mean-square error between chlorophyll a concentrations derived from the SeaBAM reflectance data and the chlorophyll a measurements is 0.62. The retrieved chlorophyll a concentrations of the OCTS data were compared with the corresponding distribution obtained by the standard OCTS algorithm.
The concentrations and distribution patterns from both algorithms match for open ocean areas. Since there are no standard
OCTS products available for yellow substance and suspended matter and no in situ measurements available for validation, the result of the retrieval by the NN for these two variables could only be assessed
by a general knowledge of their concentrations and distribution patterns.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Ken Furuya Osamu Hasegawa Takashi Yoshikawa Satoru Taguchi 《Journal of Oceanography》1998,54(5):545-552
The light-saturated maximum value (P
B
max) and initial slope (α) of the photosynthesis-irradiance (P-E) curve were examined in a warm streamer, a cold streamer and
a warm core ring off the Sanriku area in the subarctic western North Pacific Ocean during an ADEOS/OCTS Sanriku field campaign
in early May 1997. BothP
B
max and α were within the ranges of temperate populations. A regional difference was apparent inP
B
max: populations in the warm streamer tended to show higher value ranging between 1.92 and 4.74 mgC (mgChla)−1h−1 than those in the cold streamer and the warm core ring (1.35–2.87 mgC (mgChla)−1h−1). A depth variation was also observed in α in both the warm streamer and the warm core ring: shallow populations tended to
have lower α than deep populations. The depth variations in bothP
B
max and α resulted in a lower light intensity of the light saturation in a deeper population than that of a shallower one. These
depth-related variations in the P-E parameters were likely a manifestation of “shade-adaptation” of photosynthesis. Photoinhibition
was not observed over in situ surface light intensity varying below ca 1600 μmol photon m−2s−1. Water-column primary productivity was biooptically estimated to be 233 to 949 mgC m−2d−1 using vertical distributions of the P-E parameters, chlorophylla, phytoplankton light absorption and underwater irradiance. Applicability of surface data sets for estimation of water-column
productivity is discussed. 相似文献
6.
Kunio Kutsuwada 《Journal of Oceanography》1998,54(5):443-456
Data sets of surface wind and wind-stress fields in the North Pacific from September 1996 to June 1997 have been constructed
using NASA Scatterometer (NSCAT) data on-board ADEOS to investigate their variability and implications for the wind-driven
oceanic circulation. Using a weighting function decreasing with the distance between each grid and data points, and of Gaussian
type for time, daily, 10-day and monthly averages are calculated for each 1°×1° grid. Products are validated by comparison
with those calculated from in-situ measurement data at oceanic buoys around Japan (JMA) and in the equatorial area (TAO).
The RMS differences for wind direction and speed never exceed 20° and 2 ms−1, respectively, for the TAO buyos. This does not hold for data taken by JMA buoys, suggesting that the reliability in the
mid-latitudes is not good for time averages shorter than several days. Zonal integration of the Sverdrup transport in a zone
of 28°–30°N calculated from the monthly-mean products ranges between 25 and 60×106 m3s−1 (Sv) around its mean of 38 Sv. These are not so different from the Kuroshio transport values calculated from oceanic measurements. 相似文献
7.
Futoki Sakaida Masao Moriyama Hiroshi Murakami Hiromi Oaku Yasushi Mitomi Akira Mukaida Hiroshi Kawamura 《Journal of Oceanography》1998,54(5):437-442
The Ocean Color and Temperature Scanner (OCTS) aboard the Advanced Earth Observing Satellite (ADEOS) can observe ocean color
and sea surface temperature (SST) simultaneously. This paper explains the algorithm for the OCTS SST product in the NASDA
OCTS mission. In the development of the latest, third version (V3) algorithm, the OCTS match-up dataset plays an important
role, especially when the coefficients required in the MCSST equation are derived and the equation form is adjusted. As a
result of the validation using the OCTS match-up dataset, the algorithm has improved the root mean square (rms) error of the
OCTS SST up to 0.698°C although some problems remain in the match-up dataset used in the present study. 相似文献
8.
Motoaki Kishino Takashi Ishimaru Ken Furuya Tomohiko Oishi Kiyoshi Kawasaki 《Journal of Oceanography》1998,54(5):431-436
In-water algorithms for OCTS standard products were developed using in situ data and installed for operationally processing
at NASDA/EOC. This paper describes the in-water algorithms Version 1.0 for chlorophylla concentration, pigment concentration, and attenuation coefficient at a wavelength of 490 nm. The selected OCTS standard algorithms
(Ver. 1.0) are as follows:
相似文献
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