Sea Surface Brightness Temperature Research Articles

Simultaneous Doppler-Radar and Dual-Polarization Radiometer Sensing in Environmental Investigations

The spectral, angular, polarization, air and water temperatures, sea surface wave and wind featres of the sea surface radar cross section and brightness temperature, as well as the variance of distribution of sea surface radar signal Doppler shift averaged by resolution cell are considered. It is shown that the mean and the variance of distribution of reflected signals Doppler shifted may be successfully used for estimation of sea surface wave degree. Microwave radar-radiometer method for simultaneous determination of water and air temperatures, sea wave degree, and wind speed, as well as method and device for detection and identification of different types of anomalous formations of environment are described.

The dependence of S-band sea surface brightness and temperature on wind vector at normal incidence

Aircraft measurements of the S-band sea surface brightness temperature at nadir as a function of wind speed and wind direction were carried out in various regions in 1985-1989. Data set of 65 circular flights was analyzed. It is shown that for water temperature recovering the wind direction is to be taken into account. >

Polarimetric measurements of sea surface brightness temperatures using an aircraft K-band radiometer

Presents the first experimental evidence that the polarimetric brightness temperatures of sea surfaces are sensitive to ocean wind direction in the incidence angle range of 30 to 50/spl deg/. The experimental data were collected by a K-band (19.35 GHz) polarimetric wind radiometer (WINDRAD) mounted on the NASA DC-8 aircraft. A set of aircraft radiometer flights was successfully completed in November 1993. The authors performed circle flights over National Data Buoy Center (NDBC) moored buoys deployed off the northern California coast, which provided ocean wind measurements. The results indicate that passive polarimetric radiometry has a strong potential for global ocean wind speed and direction measurements from space. >

A Simplified Microwave Model and Its Application to the Determination of Some Oceanic Environmental Parametric Values, Using Multichannel Microwave Radiometric Observations

This paper proposes a simplified microwave model, linerized by Taylor expansion and incorporating observed fundamental microwave emissive properties, and discusses its application along with the least square method for determining some oceanic environmental parametric values from multichannel observation data. As a case study, microwave radiometric observations were made in vertical and horizontal polarizations at 6.7 and 18.6 GHz at incidence angles from 200 to 700 at steps of 100, and sea-surface temperature, wind speed, and sky brightness temperatures at the above dual frequencies at zenith angles from 200 to 700 were determined from a set of observed data at each incidence angle. The algorithm-derived results were compared with observed ones and showed good agreements within 10 percent of errors at incidence angles from 200 to 600; however, no good agreement was attained at large incidence angles such as 70°, except sky brightness temperature at 6.7 GHz. This disagreement may be attributed mainly to the difficulty and incompleteness in corrections such as estimation of reflected sky radiation and antenna characteristics, both for retrieval of the antenna temperature averaged over the main lobe and observation errors. This fact, however, may also suggest that observations at such larger incidence angles are of less utility.

The estimation of atmospheric corrections to one-channel (11 μ m) data from the AVHRR; simulation using AVHRR/ 2

Abstract It has been established that the sea-surface brightness temperatures Tb4 in the 11 μ m channel and Tb4in the 12 μ m channel of the Advanced Very High Resolution Radiometer (AVHRR/ 2) are linearly related to a good degree of accuracy, i.e. Tb5= α+ β Tb4 Using AVHRR/ 2 data for various dates and from different parts of the world's oceans, the parameters a and 0 have been determined. The above relation may then be used for simulating Tb5 for those cases for which only Tb4 is available (e.g. for the AVHRR on TIROS-N, NOAA-6, NOAA-8, etc.). The brightness temperature TM and pseudo-brightness temperature Tb5 then enable one to use the split-window technique for estimating atmospherically-corrected sea-surface temperatures (SSTs) from the 11μ m channel data alone. Such an atmospheric correction technique should be a possibility because the 11μ m channel of the AVHRR on the various satellites in question are almost identical This technique has been used with two split-window algorithms for correcting the...