The Advanced Microwave Scanning Radiometer-3 (AMSR3), the successor to AMSR2, is currently under development for launch in 2023. One of the goals of the AMSR3 mission is to make the retrieval limit of sea surface temperature (SST) to the coast at least 30 km (ultimately 20 km) while mitigating the effects of weather. Since AMSR3 needs to maintain the same design as AMSR2 as much as possible in order to shorten the development period, this goal must be mainly achieved by a data processing approach. Therefore, we first developed a spatial resolution enhancement algorithm for the brightness temperature ($T_{B}$) based on the Backus–Gilbert method. We aim to achieve the goal by retrieving SST using this resolution enhanced$T_{B}$. At present, the standard SST product of AMSR2 retrieves SST in waters more than 80 km from the coast using the C-band$T_{B}$. Therefore, we applied our spatial resolution enhancement algorithm to the C-band$T_{B}$of AMSR2 to retrieve hi-resolution SST (HST), evaluated how close the retrieval limit is to the coast, and compared the retrieval accuracy with the standard SST product. As a result, it was confirmed that the retrieval limit of HST is less than 30 km to the coast, with retrieval accuracy as approximating that of the standard SST product.

The Advanced Microwave Scanning Radiometer-2 (AMSR2) follow-on mission is currently being considered, and end users are demanding the acquisition of sea-surface temperature (SST) with higher spatial resolution. However, it is assumed that the AMSR2 baseline design will be followed as much as possible to shorten the development period. The SST image retrieved from the 6- or 10-GHz brightness temperatures includes random “snow” noise due to the thermal noise originating from the receiver components. In AMSR2, simple spatial averaging was performed to reduce such random noise to obtain clear SST images, but this method is not suitable for acquiring SST images with the high spatial resolution because it degrades the spatial resolution. In the AMSR2 follow-on mission, the algorithm for the AMSR2 L1R product (Backus-Gilbert method) will be applied to reduce random noise without degrading the spatial resolution. In addition, we propose equipping not only a 10-GHz channel with the conventional frequency band but also that with an extended frequency band. This letter presents the results of the study that led to these proposals required to obtain clear SST images with higher spatial resolution in the AMSR2 follow-on mission.

Three-dimensional (3D) measurement is an important means for robots to acquire information about their environment. Structure from Motion is one of these 3D measurement methods. The 3D reconstruction of objects in the environment can be obtained from pictures captured with single camera in Structure from Motion. Furthermore, the camera motion can be obtained simultaneously. Because of its simplicity, Structure from Motion has been implemented in various ways. However there is an essential problem in that the scale of the measured objects cannot be computed by Structure from Motion. In order to compute the absolute scale, other information is required. However this is difficult for robots in an unknown situation. In this paper, we propose a method that can reconstruct the absolute scale of objects using refraction. Refraction changes the light ray path between the objects and the camera. This method is implemented using only a refractive plate and single camera. The results of simulations show the effectiveness of the proposed method in both air and other media (e.g., water).

Asymmetric features of oceanic brightness temperature from spaceborne microwave imagers in high surface wind speed conditions were investigated with two kinds of collocated data. The first is simultaneous measurements of microwave brightness temperatures and surface wind vectors from the Advanced Microwave Scanning Radiometer (AMSR) and SeaWinds on Advanced Earth Observing Satellite II. The second is microwave brightness temperature observations (AMSR2 and the Special Sensor Microwave Imager Sounder) and surface wind vectors in the European Centre for Medium-Range Weather Forecasts numerical weather prediction model. Both collocated data sets showed that the vertical-polarized and the horizontal-polarized microwave brightness temperature have out-of-phase asymmetric features in terms of relative wind direction (RWD) at high surface wind speeds. Furthermore, different asymmetric features were found for the northern and Southern Hemispheres and for ascending and descending satellite orbits. Although similar asymmetric features can be found in other microwave imager studies, the causes of the asymmetry have not been fully investigated. To investigate the cause of the asymmetry, the observation frequency regarding air-sea temperature difference was examined in upwind, downwind, and crosswind cases. Two important factors contribute to the asymmetry. First, the observations from inclined polar orbit satellites provide different samplings on atmospheric stability in terms of the RWD. Second, the oceanic microwave brightness temperatures have negative correlations with atmospheric stability at high surface wind speeds. The out-of-phase asymmetry is closely related with atmospheric stability, and it appears under a high-surface-wind-speed condition.

The 6-7GHz band spaceborne microwave radiometer is very important because ocean surface temperature can be observed through cloud with highest sensitivity. Ocean surface temperature is very important in the study of global warming and others. However, 6-7GHz band is not protected in the Radio Regulations (R.R) of ITU-R. In this paper, various interferences to a spaceborne microwave radiometer imagery are classified and introduced. Some analysis is conducted for the first time in the world in the case of surface scattering of down link from mobile satellites to gateways.

Sea surface temperature (SST) observed by the advanced microwave scanning radiometer for the Earth Observing System (AMSR-E) aboard the AQUA, whose data are available from July 2002 to the present, was used to detect SST anomalies in the northern high latitudes oceans. Significant positive SST anomalies were found in many oceans of those latitudes in summer season, which may be correlated with the decrease of the arctic sea ice distribution in summer season as observed also by AMSR-E.

Simultaneous measurements of sea surface temperature (SST) by infrared and microwave sensors on single satellites are compared. The sensors are Global Imager (GLI) and Advanced Microwave Scanning Radiometer (AMSR) aboard Advanced Earth Observing Satellite-II (ADEOS-II), and Moderate Resolution Imaging Spectroradiometer (MODIS) and AMSR for Earth Observing System (AMSR-E) aboard Aqua. The characteristics of SST differences are discussed with regard to the spatial distribution and water vapor amount in atmosphere.

The C-band channels of the Advanced Microwave Scanning Radiometer (AMSR) onboard the Midori-II satellite and the AMSR for the EOS (AMSR-E) on NASA's EOS Aqua satellite suffer from man-made radio emissions, or radio frequency interference (RFI), due to the no allocation of the band to the passive microwave radiometry from space. In order to assess better frequency setting of the AMSR follow-on instrument for the Global Change Observation Mission (GCOM), we have been working on global analysis of satellite brightness temperatures and the aircraft measurement of the artificial radio emissions over Japan. We have conducted three sets of flights over Japan with simple measurement setup mainly consisting of low-gain antenna, low-noise amplifier, and spectrum analyzer. The spectra obtained in the frequency range between 6 and 8GHz are being used to assess how to mitigate the RFI problem for the AMSR follow-on instrument.

An accuracy of sea surface temperature (SST) retrieved from passive microwave radiometers can be improved by adequate corrections on wind effects. In an older version of SST algorithm used for the Advanced Microwave Scanning Radiometer for (AMSR-E) aboard the AQUA, a coefficient used for wind effect correction is constant in the global ocean. Comparison of AMSR-E and buoys SST showed that the correction coefficient is not constant, but varied seasonally and locally. In a new version of AMSR-E SST algorithm, seasonal variations of wind effect correction are adopted. In this presentation, seasonal changes of correction coefficient are given.

Three years data of sea surface temperature (SST) from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) aboard the NASA/AQUA are available since July 2002. SST measurement by passive microwave radiometers has advantages of observation capability through clouds, and of easy handling due to small data volume. AMSR-E SST can be used to monitor a future global warming. To do this, careful calibration of AMSR-E SST is necessary, since a possible change of SST may be small such as an order of 0.1-0.2 oC during several years. In this presentation, a method of calibrating AMSR-E SST is presented.

An algorithm of retrieving wind speed by combing 6 and 10GHz of the Advanced Microwave Scanning Radiometer (AMSR) is developed. Even though this algorithm can be applied to both under no-rain and rainy conditions, a main purpose of development is application to inside storms such as typhoons and hurricanes. Wind speed equivalence derived from AMSR is investigated inside several hurricanes in the Atlantic Ocean, and a capability of distinguishing wind speeds from around 20 to 70 m/s is confirmed.

The Advanced Microwave Scanning Radiometer (AMSR) on board the Advanced Earth Observing Satellite-II (ADEOS-II, or Midori-II) has two channels in the oxygen absorption bands. This is the first attempt to obtain brightness temperatures at the channels by a conically scanning microwave radiometer with high spatial resolution. Potential applications of the channels include the air temperature monitoring, improving geophysical parameter retrieval by incorporating the information of air temperature, and sensing hydrometeor information by utilizing the different penetration depth compared to other window-frequency channels. Since one of the future trends of passive microwave instruments is to integrate the imaging and sounding capabilities into single conical scanning instrument, AMSR data will provide some insights to those future plans. We introduce some potential uses of the channels in conjunction with the preliminary examples of actual AMSR data

Accuracies of sea surface temperature (SST) retrieved from the Advanced Microwave Scanning Radiometer (AMSR) aboard the Advanced Earth Observing Satellite-II (ADEOS-II) are compared between two methods of removing wind direction effects; one is using only AMSR data, and the other is using the SeaWinds aboard ADEOS-II. The result is that rms of SST difference between AMSR and buoy is 0.626 degC from the method of using only AMSR, and is 0.660 degC from the one of using SeaWinds

Sea surface temperature (SST) retrieved from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) aboard NASA Aqua is used as operational data source for monitoring oceanic conditions conducted by the Japan Meteorological Agency, and monitoring fisheries conditions conducted by the Japan Fisheries Information Service Center. In this paper, evaluation of AMSR-E SST accuracy is presented, and those SST applications are reported

The Advanced Microwave Scanning Radiometer for EOS (AMSR-E) was developed and provided to NASA's EOS Aqua satellite by the National Space Development Agency of Japan (NASDA). AMSR-E is the modified version of AMSR onboard the Advanced Earth Orbiting Satellite-II (ADEOS-II, currently called the Midori-II). AMSR-E has been in operation since June 2002 and providing continuous data record. This paper presents the status of post-launch calibration and data evaluation of the instrument.

The Advanced Microwave Scanning Radiometer for EOS (AMSR-E) aboard the Advanced Earth Orbiting Satellite-II (ADEOS-II) and AMSR-E aboard the AQUA have an ability to observe sea surface temperature (SST) through clouds. An accuracy of observed SST is 0.64 C estimated by comparing with oceanic buoy's SST. Spatial resolution of two AMSRs' SST is about 50 km, which is determined by AMSR's antenna diameter.

The Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) was developed and provided to the National Aeronautics and Space Administration's EOS Aqua satellite by the National Space Development Agency of Japan, as one of the indispensable instruments for Aqua's mission. AMSR-E is a modified version of AMSR that was launched December 2002 aboard the Advanced Earth Observing Satellite-II (ADEOS-II). It is a six-frequency dual-polarized total-power passive microwave radiometer that observes water-related geophysical parameters supporting global change science and monitoring efforts. The hardware improvements over existing spaceborne microwave radiometers for Earth imaging include the largest main reflector of its kind and addition of 6.925-GHz channels. These improvements provide finer spatial resolution and the capability to retrieve sea surface temperature and soil moisture information on a global basis. This paper provides an overview of the instrument characteristics, mission objectives, and data products.

In 2002, two spaceborne microwave radiometers were launched to provide new observation data. One sensor is the Advanced Microwave Scanning Radiometer (AMSR), aboard the Advanced Earth Observing Satellite-II (ADEOS-II) of the National Space Development Agency of Japan (NASDA). The other is AMSR-E, aboard Aqua of the National Aeronautics and Space Administration (NASA). AMSR and AMSR-E are almost identical sensors, and have lower frequencies 6 and 10 GHz, in comparison with preceding sensors, such as the Special Sensor Microwave/Imager (SSM/I). In addition to geophysical products currently retrieved from the SSM/I, new products of sea surface temperature and soil moisture have been retrieved from AMSR and AMSR-E by using those lower frequencies. Eleven Principal Investigators were assigned by NASDA to develop algorithms to retrieve geophysical products, and their programs have been installed at the Earth Observation Research Center of NASDA. Geophysical products are currently being validated by several methods, such as using existing in situ data, employing instruments in field observations, and comparing data with other sensor's data.

The National Space Development Agency of Japan (NASDA) developed two spaceborne microwave radiometers: the Advanced Microwave Scanning Radiometer (AMSR) for NASDA's Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR-E for NASA's Aqua satellite. Each instrument, as well as the combination of instruments, will provide valuable information for understanding the mechanism of global water and energy circulation. To accomplish the mission, it is necessary to provide reliable, well-calibrated data. Several post-launch calibration and validation activities are then planned in addition to two-point, on-board calibration of the instruments.

Several types of browse images of Advanced Microwave Scanning Radiometer (AMSR) and AMSR-E will be available to the public use for purposes to observe storms, sea ice, and others. The AMSR/AMSR-E data will be also transferred to the Japan Meteorological Agency (JMA) for weather forecast, and to the Japan Fisheries Information Center (JAFIC) for marine fisheries.