Solar radiation, ground surface and air temperatures change periodically day by day. Then we measured the surface temperature, air temperature, humidity and wind velocity on various types of land covers such as concrete, asphalt, soil and grass every hour for one cycle namely 24 hours. The relationship between the diurnal radiant energy from ground surface and air and global solar irradiance were studied as a function of time. A linear relationship was established between them, when the phases of them were synchronized. The values of parameters of the relationship were determined using experimental data and compared with the estimated values using the radiation balance model. Finally, we tried to estimate the surface radiant energy in a day using Landsat/TM data.

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In this paper, M sequence coded subsurface radar is proposed for signal processing to cancel the time-sidelobe. Generally, conventional signal processing performed by NRZ-M sequence coded pulses performs poorly due to its short code length. It is well known that the longer the code length, the shorter the time-sidelobe level. However, if the longer M sequence coded pulses are used, the signal processing time will be longer for pulse compression, which is not practical. Therefore, the method of reducing time-sidelobe is proposed even the M sequence code length is small. In this case, RZ-M sequence coded pulses are introduced as reference signal. Computer simulation shows the excellent effect and the field experiment shows the superior result than the conventional processing.

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Early results from the vicarious calibration activities for ASTER/VNIR and SWIR in Japan are described. An influence due to solar irradiance models on the vicarious calibration for visible to short wave infrared region is clarified. Also vicarious calibration activities are introduced together with the radiometric calibration coefficients with vicarious calibration data. EOS standard solar irradiance model of WRC is compared with the widely used MODTRAN 4.0 based solar irradiance. The percent difference both is below 1 % for the visible to near infrared region while that for short wave infrared region is +3.1 to -10%. The calibration coefficients are compared with the onboard calibration lamp data derived coefficients. Both show a good coincidence. As a conclusion, it is found that vicarious calibration accuracy in the visible to near infrared wavelength region is around ±4% while that in the short wave infrared region is approximately ±15%.

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The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) launched in December 1999, is a high-spatial-resolution multispectral imager with 14 bands from the visible and near-infrared (VNIR) to the thermal infrared (TIR) regions. In the present paper, the brightness temperatures at five TIR bands derived from the onboard calibration (OBC) are verified based on two vicarious calibration (VC) experiments at Lake Kasumigaura, Japan, on 16 May 2000 and 16 March 2001. In each experiment, the bulk and skin temperatures of a selected area on the lake were measured at the satellite overpass time, and the atmospheric profiles for pressure, temperature, andmoisture were also measured by two radiosondes launched before and after that time. These parameters are used for radiative transfer computations using MODTRAN 3.7, and then the top of the atmosphere (TOA) brightness temperature and its error bar are predicted for each band. On the other hand, the ASTER data for the both experiments are calibrated using the radiometric calibration coefficients (RCCs) of version 1.02 that apply the gain coefficients determined from the long-term calibration on 12 March 2000. As a result, the difference of the TOA brightness temperature between OBC and VC shows to be within 0.6 K for all bands in the both experiments. This allows us to estimate that the RCCs of version 1.02 satisfy the absolute-temperature-accuracy requirement (within 1 K for the range from 270 to 340 K) for the ASTER data used.

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Lake Kasumigaura is polluted by massive growth of blue green algae during a typical summer. Measuring a quantity of chlorophyll-a in the phytoplankton is of importance in tackling with the lake water pollution problem. In this paper, a remote sensing method to estimate distribution of rich chlorophyll-a concentration as well as suspended solids concentration which is important parameter of turbidity in lakes or inland seas is proposed.

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An AOTF is a solid-state electro-optical device which acts as an electronically tunable spectral filter. The specific point of the device is that we can simultaneously obtain two diffracted beams perpendicularly polarized each other. So we developed an imaging spectro-polarimeter employing a visible (450-700nm) AOTF as well as a visible and up to near infrared (500-1, 000nm) AOTF. This paper first presents the concept, configuration, and performance of the instrument and, then the examples of experiments both in a laboratory and in the fields.

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