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91.
Relations between sea-surface temperature (T
s) and heat flux at the sea surface (F) have been investigated using data from ocean observation buoys located off Shikoku in the Sea of Japan and in the East China
Sea. Wavelet transformation decomposed F and T
s to wavelet coefficients (WLC) in the period-time domain. Assuming one-dimensional heat transfer by eddy diffusion in the
upper ocean, the phase difference (δθ) defined as the difference between the phase of the temporal change rate of T
s, and the phase of F ranges statistically from 0 to +π/4 when F changes T
s, and is around −π/2 when heat convergence in the sea (Av) forces T
s. The δθ values are distributed from 0 to +π/4 at one-day and one-year periods at all buoys. WLC amplitude (WLCA) of F at periods from 16 to 32 day periods, which may be caused by the atmospheric ridge-trough systems, maintains energy longer
than WLCA at periods from 2 to 16 days, which may be caused by monsoonal surges. At periods from 2 to 64 days, δθ values distribute
from 0 to +π/4 or around −π/2 at each event, reflecting the surroundings of each ocean, i.e., Kuroshio recirculation in the
off-Shikoku area, water-temperature front in the Sea of Japan, and water exchange in the continental shelf edge in the East
China Sea. We demonstrate that the wavelet analysis can characterize the correspondence between irregular signals of F and T
s in various time scales and locations.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
92.
The authors have verified a regression model for the evaluation of the daily amplitude of sea surface temperature (ΔSST) proposed
by Kawai and Kawamura (2002). The authors investigated the accuracy of satellite data used for the evaluation and showed that
ΔSST error caused by satellite data error is less than ±0.7 K. The evaluated ΔSSTs were compared with in situ values. Its
root-mean-square error is about 0.3 K or less, except for a coastal region, and it has a bias of more than +0.1 K in the tropics.
This bias can be removed by considering latent heat flux.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
93.
Distributions of low molecular weight dicarboxylic acids in the North Pacific aerosol samples 总被引:1,自引:0,他引:1
Marine aerosol samples collected from the North Pacific atmosphere were studied for molecular distributions of dicarboxylic acids by using a capillary gas chromatography and mass spectrometery. A homologous series of dicarboxylic acids (C2–C10) was detected in the marine aerosol samples as dibutyl esters. All the samples showed that the smallest diacid (oxalic acid: C2) was the most abundant and comprised 41–67% of the total diacids. The second most abundant species was malonic acid (C3) or succinic acid (C4). The diacids with more carbon numbers were generally less abundant. Total diacid concentration range was 17–1040 ng m–3, which accounted for up to 1.6% of total aerosol mass. This indicates that low molecular weight dicarboxylic acids are important class of organic compounds in the marine atmosphere. The concentrations were generally higher in the western North Pacific and lower in the central North Pacific. The major portion of diacids is probably derived from the Asian Continent and East Asian countries by long-range atmospheric transport and partly fromin situ photochemical production in the marine atmosphere. 相似文献
94.
The Visible and Infrared Scanner (VIRS) aboard the Tropical Rainfall Measuring Mission (TRMM) is a five-channel radiometer
with wavelength from 0.6 to 12 μm. Daily 0.125° sea surface temperature (SST) data from VIRS were first produced at the National
Space Development Agency (NASDA) for comparison with SST from TRMM Microwave Imager (TMI). In order to obtain accurate high
spatial resolution SST for the merging of SST from infrared and microwave measurements, new SST retrieval coefficients of
the Multichannel SST (MCSST) algorithm were generated using the global matchups from VIRS brightness temperature (BT) and
Global Telecommunications System (GTS) SST. Cloud detection was improved and striping noise was eliminated. One-year global
VIRS level-1B data were reprocessed using the MCSST algorithm and the advanced cloud/noise treatments. The bias and standard
deviation between VIRS split-window SST and in situ SST are 0.10°C and 0.63°C, and for triple-window SST, are 0.06°C and 0.48°C.
The results indicate that the reprocessing algorithm is capable of retrieving high quality SST from VIRS data.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
95.
Il-Chan Kim Young Ja Kim Yong-Dal Yoon Shoji Kawamura Yong-Sung Lee Jae-Seong Lee 《Marine environmental research》2004,58(2-5):125
To use two small fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae) and the Japanese medaka Oryzias latipes (Belloniformes) as testing models in molecular ecotoxicology, we have cloned the cytochrome P450 1A (CYP1A) gene after screening of both genomic DNA libraries, and sequenced 11,863 and 7,243 bp including all the exons and introns with promoter regions, respectively. The Rivulus and the medaka CYP1A gene consisted of seven exons (including non-coding exons) with high homology to mammals. In the promoter region, Rivulus CYP1A gene has seven xenobiotic response elements (XREs) and two metal response elements (MREs), while the Japanese medaka CYP1A gene has six XREs and four MREs. Interestingly, medaka CYP1A gene has a number of MREs at the promoter, which may affect its response on metal exposure. We describe here the gene structure of both fish CYP1A genes. 相似文献
96.
Principal component analysis (PCA) was applied to the displacement field recorded at 147 GPS stations in the Kanto-Tokai district, Japan, for the period from January 1999 to February 2003. Some prominent geophysical events occurred during this period. Using PCA, we attempted to decompose the displacement field into some representative spatial modes and their corresponding temporal modes to quantitatively extract the primary geophysical events that have caused rapid crustal deformation in this region. The displacement field was roughly decomposed into modes corresponding to the following three major events: (1) The Miyake-Kozu volcanic event, which occurred in the region south of Tokyo in 2000. It included large-scale dyke intrusion and intensive earthquake swarm between the Miyakejima and Kozushima islands. (2) The Tokai slow-slip event, which is considered to have begun just after the Miyake-Kozu volcanic event and is ongoing as of November 2005. It occurred on the boundary between the subducting Philippine Sea Plate and the overriding Eurasian (Amurian) Plate in the Tokai district. (3) The Boso slow-slip event, which lasted for approximately 10 days in October 2002. It occurred on the boundary between the subducting Pacific Plate and the overriding North American Plate near the Boso Peninsula. In the decomposition process, we combined the mode-rotation technique with ordinary PCA. This is because PCA causes contamination between modes, i.e., a mode obtained with PCA is contaminated by other modes. For example, the first principal mode corresponding to the Miyake-Kozu volcanic event, which is by far the largest in magnitude, was clearly seen in many other modes. In order to remove such contamination, we applied the mode-rotation technique, in which the principal axes derived from PCA are rotated so as to minimize the correlation coefficients between different temporal modes for a time period in which some prominent change occurs. Combining the mode-rotation technique with PCA exhibited a better performance in separating the displacement field. 相似文献
97.
Hiroshi Kawamura Huiling Qin Kohtaro Hosoda Futoki Sakaida Chunhua Qiu 《Journal of Oceanography》2010,66(6):855-864
Producing high-quality match-ups coupling the Japanese geostationary satellite, Himawari-6 (H6), and buoy SST observations,
we have developed the new SST retrieval method. Kawamura et al. (2010) developed the previous version of SST product called MTSAT SST, which left several scientific/technical questions.
For solving them, 6,711 algorithm tuning match-ups with precise navigation and 240,476 validation match-ups are generated
for covering all seasons and wide ocean coverage. For discriminating the previous MTSAT SST, we call the new version of SST
H6 SST. It is found that the SZA dependences of MTSAT SST algorithm are different from area to area of SZA > 40–50° N/S. The
regionally different SZA dependences are treated by dividing the H6 disk coverage into five areas by the latitude lines of
40° N/S first and the longitude lines of 100° K and 180° K. Using the algorithm tuning match-ups, Nonlinear SST (NLSST) equations
are derived for all of the five areas. Though the sun zenith angle dependency correction term is also examined, there is no
significant regional difference. Therefore, this term is used in the H6 SST algorithm again. The new H6 SST equation is formed
by the areal NLSST and the sun zenith angle dependency term for each area. The statistical evaluation of H6 SST using the
validation match-ups show the small negative biases and the RMS errors of about 0.74° K for each area. For the full H6 disk,
the bias is −0.1° K and the RMS error 0.74° K. The histogram of H6 SST minus the in situ SST for each area has a similar Gaussian shape with small negative skewness, and the monthly validation of H6 SST for each
area is consistent with those for the whole period and the histograms 相似文献
98.
Hideyuki Kawamura Toshimichi Ito Takuya Kobayashi Shigeyoshi Otosaka Naoki Hirose Orihiko Togawa 《Journal of Oceanography》2010,66(5):649-662
A numerical experiment is carried out to reproduce distribution of concentration of 90Sr and 137Cs, estimate their total amount and verify their source in the Japan Sea. Model results are in good agreement with observational
findings in the Japan Sea expeditions between 1997 and 2002 by the Japan Atomic Energy Agency. Vertical profiles of the concentration
of 90Sr and 137Cs show exponential decreases with depth from the sea surface to the sea bottom. From the model and observational results,
it is suggested that the concentration of 90Sr and 137Cs in the surface layer is approximately in the range of 1.0–1.5 Bq/m3 and 2.0–2.5 Bq/m3, respectively. On the other hand, it is found that the concentration in the intermediate and deep layer
is higher than that observed in the northwestern Pacific Ocean, suggesting active winter convection in the Japan Sea. The
total amount of 90Sr and 137Cs in the seawater is evaluated to be 1.34 × 1015 Bq and 2.02 × 1015 Bq, respectively, in the numerical experiment, which demonstrates an estimation by observational data obtained in the Japan
Sea expeditions. The total amount of 90Sr and 137Cs changed during the second half of 20th century corresponding to deposition at the sea surface with the maximums of 4.86
× 1015 Bq for 90Sr and 7.33 × 1015 Bq for 137Cs, respectively, in the mid-1960s. The numerical experiment suggests that the main source of 90Sr and 137Cs has been global fallout, although there have been some potential sources in the Japan Sea. 相似文献
99.
To investigate the feasibility and methodology of new generation sea surface temperature (SST) maps that combine various satellite
measurements, we have quantitatively evaluated SST availabilities of NOAA AVHRR (National Oceanic and Atmospheric Administration,
Advanced Very High Resolution Radiometer), GMS S-VISSR (Geostationary Meteorological Satellite, Stretched-Visible Infrared
Spin Scan Radiometer) and TRMM MI (Tropical Rainfall Measuring Mission, Microwave Imager: TMI), during the one-year period
from October 1999 to September 2000. The advantage of satellite microwave SST measurements is the ability to penetrate the
clouds that contaminate satellite infrared measurements. Daily SST availabilities were calculated in the overlapping coverage
from 20°N to 38°N and 120°E to 160°E. The annual-mean SST availabilities of AVHRR, S-VISSR and TMI are 48%, 56% and 78%, respectively.
There are large seasonal variations in the availabilities of infrared measurements. The latitude-time plots of one-degree
zonal mean SST availabilities of S-VISSR and TMI in the region from 38°S to 38°N and 80°E to 160°W show significant zonal
variations, which are influenced by the atmospheric circulation such as the Subtropical High and the Intertropical Convergence
Zone. The SST availabilities of S-VISSR and TMI in the five selected regions have large regional variations, ranging from
35% to 74% and 62% to 88% for S-VISSR and TMI, respectively. The present statistical analyses of SST availabilities in the
infrared and microwave measurements indicate that 1) a daily cloud-free high-spatial resolution may be achieved by merging
various SST measurements since their deficiencies compensate each other, and 2) nevertheless, it is necessary to take account
of the seasonal and regional variations of SST availabilities of different satellite sensors for the development of merging
technology.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
100.
Merging satellite infrared and microwave SSTs: Methodology and evaluation of the new SST 总被引:3,自引:0,他引:3
The Global Ocean Data Assimilation Experiment (GODAE) requires the availability of a global analyzed SST field with high-resolution
in space (at least 10 km) and time (at least 24 hours). The new generation SST products would be based on the merging of SSTs
from various satellites data and in situ measurements. The merging of satellite infrared and microwave SST data is investigated in this paper. After pre-processing
of the individual satellite data, objective analysis was applied to merge the SST data from NOAA AVHRR (National Oceanic and
Atmospheric Administration, Advanced Very High Resolution Radiometer), GMS S-VISSR (Geostationary Meteorological Satellite,
Stretched-Visible Infrared Spin Scan Radiometer), TRMM MI (Tropical Rainfall Measuring Mission, Microwave Imager: TMI) and
VIRS (Visible and Infrared Scanner). The 0.05° daily cloud-free SST products were generated in three regions, viz., the Kuroshio
region, the Asia-Pacific Region and the Pacific, during one-year period of October 1999 to September 2000. Comparisons of
the merged SSTs with Japan Meteorological Agency (JMA) buoy SSTs show that, with considerable error sources from individual
satellite data and merging procedure, an accuracy of 0.95 K is achieved. The results demonstrate the practicality and advantages
of merging SST measurements from various satellite sensors. 相似文献