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1.
Kohtaro Hosoda 《Journal of Oceanography》2012,68(5):671-685
The relationship between sea surface temperature (SST) and net heat flux (NHF) in the North Pacific over weekly to annual period bands was investigated using gridded datasets of SST obtained by the Advanced Microwave Scanning Radiometer for the Earth Observing System, and flux data produced by the Modern-era Retrospective-analysis for Research and Applications Reanalysis. This study focused on the phase difference between the SST and NHF, which can suggest the driving force between two co-varying parameters. The SST delay behind the NHF, with phase differences from π/4 to π/2, which suggests that the SST change would be controlled by the NHF, was commonly found over all periods. In the intra-annual (100- to 200-day periods) band, part of the coherent variations showed negative phase differences (around ?π to ?π/3), which were found in the western North Pacific and along ~30°N in the central North Pacific. The spatial scales of SST variability in the shorter band (weekly to intraseasonal: less than 100-day periods) are dominantly over 200?km. In contrast, the scales in the intra-annual band were in the range 50–150?km, where the negative phase differences were frequently found. 相似文献
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Kohtaro Hosoda Hiroshi Murakami Akira Shibata Futoki Sakaida Hiroshi Kawamura 《Journal of Oceanography》2006,62(3):339-350
This study compares infrared and microwave measurements of sea surface temperature (SST) obtained by a single satellite. The
simultaneous observation from the Global Imager (GLI: infrared) and the Advanced Microwave Scanning Radiometer (AMSR: microwave)
aboard the Advanced Earth Observing Satellite-II (ADEOS-II) provided an opportunity for the intercomparison. The GLI-and AMSR-derived
SSTs from April to October 2003 are analyzed with other ancillary data including surface wind speed and water vapor retrieved
by AMSR and SeaWinds on ADEOS-II. We found no measurable bias (defined as GLI minus AMSR), while the standard deviation of
difference is less than 1°C. In low water vapor conditions, the GLI SST has a positive bias less than 0.2°C, and in high water
vapor conditions, it has a negative (positive) bias during the daytime (nighttime). The low spatial resolution of AMSR is
another factor underlying the geographical distribution of the differences. The cloud detection problem in the GLI algorithm
also affects the difference. The large differences in high-latitude region during the nighttime might be due to the GLI cloud-detection
algorithm. AMSR SST has a negative bias during the daytime with low wind speed (less than 7 ms−1), which might be related to the correction for surface wind effects in the AMSR SST algorithm. 相似文献
4.
This study developed a post-processing quality check (QC) process to eliminate cloud contamination in infrared sea surface
temperature (SST) without manual handling. Cloudiness of a pixel was evaluated quantitatively, in which the graduated verifications
and a comprehensive decision from a combination of several tests were conducted. Additionally, the quality of SST data at
the pixel was measured by acceptable limits from reference SST, which were obtained from historical data. The QC processed
data showed good accuracy below 0.8°C, even in the near-cloud area. Before the QC, their accuracies including near-cloud areas
were as poor as 2–5°C. 相似文献
5.
Wirasatriya Anindya Kawamura Hiroshi Helmi Muhammad Sugianto Denny Nugroho Shimada Teruhisa Hosoda Kohtaro Handoyo Gentur Putra Yoppik Disma Girindra Koch Magaly 《Ocean Dynamics》2020,70(6):771-786
Ocean Dynamics - The short-lived events of high SST are called hot events (HEs) and can only be generated under the conditions of large daily heat gain due to strong solar radiation and weak wind.... 相似文献
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Kohtaro Hosoda 《Journal of Oceanography》2010,66(4):439-473
Satellite-based microwave radiometers can measure sea surface temperature (SST) over wide areas, even under cloud cover, owing
to the weak absorption of microwaves by cloud droplets. This advantage is not available in the case of infrared observations,
hence SST data derived from microwave radiometers have been widely used for operational and research purposes in recent years.
This paper reviews the significant algorithms, validations, and applications related to microwave observation of SST. The
history and specifications of past and present microwave radiometers are also documented. Various physical properties, including
sea surface salinity, sea surface wind, molecules in the atmosphere, and clouds, affect the accuracy of SST data estimated
by satellite-based microwave radiometers. Estimation algorithms are designed to correct these effects by using microwave measurements
in several frequency channels and by using data of ancillary geophysical parameters. Validation studies have shown that microwave
radiometer SST data have high accuracy that is comparable to the accuracy of data obtained from infrared measurements. However,
certain persistent problems, such as sea-surface wind correction, remain to be solved. 相似文献
8.
In the previous study, merged sea surface temperature (SST) dataset called “New Generation SST” has been produced from several
infrared and microwave satellite SSTs through an objective mapping. Here we examine the merged SST by comparison with moored
buoy SST at 1 m depth, which is treated as true sea surface temperature. Comparison between wavelet spectra of merged and
buoy SSTs shows that the former have larger amplitudes than those of the latter, which is partly explained as an aliasing
effect due to TRMM Microwave Imager (TMI) aboard Tropical Rainfall Measuring Mission (TRMM) sampling on merged products. Coherency
between wavelet-decomposed merged and buoy SSTs has high values in autumn and low ones in winter to spring. In winter, phase
differences between them are positive, meaning that wavelet components of merged SST lag those of buoy SST. Reasons for delay
and low coherency are: (1) seasonal components of merged SSTs are strongly affected by a lack of infrared SSTs due to clouds
in winter, and (2) small-scale oceanic features, undetectable by coarse-resolution microwave SSTs, are blurred by the merging
process. Improvements of merging methodology are discussed with regard to present study results. 相似文献
9.
Sea surface temperature observation by Global Imager (GLI)/ADEOS-II: Algorithm and accuracy of the product 总被引:1,自引:0,他引:1
Futoki Sakaida Kohtaro Hosoda Masao Moriyama Hiroshi Murakami Akira Mukaida Hiroshi Kawamura 《Journal of Oceanography》2006,62(3):311-319
A sea surface temperature (SST) retrieval algorithm for Global Imager (GLI) aboard the ADEOS-II satellite has been developed.
The algorithm is used to produce the standard SST product in the Japan Aerospace Exploration Agency (JAXA). The algorithm
for cloud screening is formed by combinations of various types of tests to detect cloud-contaminated pixels. The combination
is changed according to the solar zenith angle, which enables us to detect clouds even in the sun glitter region in daytime.
The parameters in the cloud-detection tests have been tuned using the GLI global observations. SST is calculated by the Multi-Channel
SST (MCSST) technique from the detected clear pixels. Using drifting buoy measurements, match-up data are produced to derive
the coefficients of the MCSST equations and to examine their performance. The bias and RMSE of the GLI SST are 0.03 K and
0.66 K for daytime and, −0.01 K and 0.70 K for nighttime, respectively. 相似文献
10.
An algorithm for estimating global sea surface temperatures (SST) from data obtained from the Moderate Resolution Imaging
Spectroradiometer (MODIS) aboard the Aqua satellite has been developed empirically. Four atmospheric correction models for
MODIS observations are examined, and the effects of ancillary data for corrections are discussed. A nonlinear (NLSST) model
using high-temporal-resolution climatological SSTs as the first guess shows high accuracy and availability. The addition of
a temperature-proportional term to the NLSST model effectively improves the estimate. 相似文献