The Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) had been operated in special slow rotation mode to obtain continuous brightness temperatures for the inter-comparison with those of AMSR2 on the Global Change Observation Mission-Water (GCOM-W) for three years. Although its observation coverage is sparse and some calibration uncertainties exist, the data are still very useful for straightforward inter-comparison.

The Global Change Observation Mission 1st-Water (GCOM-W1) satellite, which was launched by the Japan Aerospace Exploration Agency in May 2012, contains an Advanced Microwave Scanning Radiometer-2 (AMSR2). The AMSR2 provides multifrequency measurements of microwave energy (brightness temperature) emitted by the Earth's surface and atmosphere. However, each frequency field of view (FOV) differs in size because of its hardware design. For the retrieval of more accurate geophysical parameters from multifrequency brightness temperatures, the brightness temperatures should be modified to be the same as measured in the same FOV. The Backus-Gilbert (BG) method is one of the antenna pattern matching techniques used for this modification. We applied the BG method to the AMSR2 data to define a new data set of modified brightness temperatures, a level 1R (L1R) product that is freely and widely available. We optimized the implementation of the BG method to obtain the L1R product, with smoothing factors dynamically determined for all modified brightness temperatures. This paper describes the implementation method, including the criterion used to determine the smoothing factors and presents a quality assessment of the L1R product.

The Advanced Microwave Scanning Radiometer 2 (AMSR2) on board the Global Change Observation Mission — Water (GCOM-W or “SHIZUKU”) was launched on May 18, 2012 (JST), and continuous its observation from the A-Train orbit more than one year successfully. Validation results of AMSR2 standard products satisfied required release accuracy, and JAXA has released AMSR2 geophysical parameters to public though the GCOM-W1 Data Providing Service System (https://gcom-w1.jaxa.jp) since May 17, 2013. In addition to AMSR2 standard products, research products are defined to extend possible utilization of AMSR2 data. We are also planning to integrate the water-related parameters derived from AMSR2 with those from AMSR-E to produce long-term continuous datasets for climate change studies.

Here, we describe the characteristics of brightness temperature (Tb) measured by the Advanced Microwave Scanning Radiometer-2 (AMSR2) onboard the Global Change Observation Mission 1st-Water (GCOM-W1). This mission aims to achieve long-term global monitoring of Earth using two polar-orbiting satellite observation systems with three consecutive generations. GCOM-W1, the first satellite of the GCOM-W (Water) series, was launched successfully on May 18, 2012. AMSR2 is a single-mission instrument onboard the GCOM-W1 satellite. The basic characteristics of AMSR2 are similar to those of its predecessor, AMSR-E; this allows the continuation of AMSR-E observations but with several improvements, including a larger main reflector (2.0-m diameter), additional channels at C-band frequency, an improved calibration system, and increased reliability imparted by the addition of a redundant momentum wheel. Since July 3, 2012, the instrument has functioned properly and has accumulated a data set of Tb measurements. During the initial calibration and validation period, Tb values are being evaluated and characterized according to various methodologies, including intercalibration between similar microwave radiometers [e.g., the Tropical Rainfall Measuring Mission Microwave Imager (TMI)] based on radiative transfer computations. The intercalibration results for the ocean area as the cold end and the rainforest area the as warm end demonstrate that Tb measured by AMSR2 exhibits no apparent seasonal variation, with a maximum calibration difference of approximately 5 K compared to TMI and AMSR-E. This calibration difference appears to depend on the Tb of the observed object.

The Advanced Microwave Scanning Radiometer 2 (AMSR2) on board the Global Change Observation Mission - Water (GCOM-W or “SHIZUKU”) was launched on May 18, 2012 (JST), and continuous its observation from the ATrain orbit more than one year successfully. Validation results of AMSR2 standard products satisfied required release accuracy, and JAXA has released AMSR2 geophysical parameters to public though the GCOM-W1 Data Providing Service System (https://gcom-w1.jaxa.jp) since May 17, 2013. Definition of AMSR2 research products are currently discussed under the AMSR2 Science Team and some candidate algorithms are being processed and tested for operation utilization in some user agencies.

The Advanced Microwave Scanning Radiometer 2 (AMSR2) on board the Global Change Observation Mission - Water 1st (GCOM-W1 or “SHIZUKU”) was launched on May 18, 2012 (JST), and continuous its observation from the A-Train orbit more than one year successfully. Validation results of eight geophysical parameters of AMSR2 standard products show that all products satisfied required release accuracy, and JAXA has released AMSR2 geophysical parameters to public though the GCOM-W1 Data Providing Service System (https://gcom-w1.jaxa.jp) since May 17, 2013.

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.

The Advanced Microwave Scanning Radiometer-2 (AMSR2) will be launched as a single mission instrument onboard on the first satellite of the Water Series of Global Change Observation Mission (GCOM-W1). AMSR2 is multi-frequency, total-power microwave radiometer system with dual polarization channels for all frequency bands, and a successor of AMSR on the Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR for the Earth Observing System (AMSR-E) on NASA's Aqua satellite. Participation of GCOM-W1 on the A-Train constellation is now being coordinated. Current target launch year of GCOM-W1 is in Japanese fiscal year 2011. Although GCOM-W1 will not be capable of observing ocean surface vector winds, the future possibility of installing a U.S. provided scatterometer on GCOM-W2 is under discussion. Simultaneous active and passive microwave measurements will enhance the water cycle observation capability of the GCOM-W series.

The Japan Aerospace Exploration Agency (JAXA) is pursuing the Global Change Observation Mission (GCOM) that will inherit the Advanced Earth Observing Satellite-II (ADEOS-II) mission and develop into long-term monitoring. GCOM is not the name of a single satellite, but of a mission that consists of two series of medium-size satellites, GCOM-W (Water) and GCOM-C (Climate), and three generations of each satellite series to continue the observations for 10 to 15 years. The Advanced Microwave Scanning Radiometer-2 (AMSR2) will be the single instrument on the GCOM-W1 satellite, which is the first satellite of the GCOM series. The second satellite will be GCOM-C1, which will carry the Second-generation Global Imager (SGLI). GCOM-W will mainly contribute to the observations related to global water and energy circulation, while GCOM-C will contribute to the measurements related to the carbon cycle and radiation budget. Current target launch years are calendar year 2011 for GCOM-W1 and 2014 for C1.

The Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) was built in Japan, and it has been flying on the Aqua satellite since May 2002. Aqua has completed its prime mission in September 2008. The observations from AMSR-E are being used by scientists all over the world in conjunction with other ATrain satellite instruments to monitor and understand hydrological processes over land, ocean, and in the cryosphere. The status of AMSR-E will be presented. Images of AMSR-E products will be shown, as well as a summary of the ongoing research with these data. AMSR-E's follow-on instrument, AMSR2, will be launched on JAXA's GCOM-W1 satellite in Japanese fiscal year 2011. The AMSR2 instrument will be similar to AMSR-E with some important enhancements, and will provide a critical bridge of climate observations until the first Microwave Imager Sounder (MIS) flies on the second NPOESS satellite in 2016 or any other radiometer planned, and yet unknown to the international research community. JAXA and NASA are discussing whether to place GCOM-W1 in the same orbit as Aqua, as part of the Atrain constellation. The benefits of the collocation of the two AMSRs will be discussed and examples given of the research possibilities.

In order to evaluate variations in the physical properties of winter precipitation over the Sea of Japan, we analyzed the Wakasa Bay Experiment 2003 datasets. The results show that synoptic scale differences in freezing-level height (FLH) were observed between extra-tropical low cases and winter monsoon and upper cold low cases, and that, frozen-particle density and cloud liquid water content (CLWC) observed at the surface showed great variation independent of the precipitation rate, although positive correlation may exist between these two properties. The radiative transfer model (RTM) simulation and the validation using the advanced microwave scanning radiometer on EOS (AMSR-E) and millimeter-wave imaging radiometer brightness temperatures (TBs) indicate that sensitivity to frozen precipitation rate (0-5 mm ldr h-1) was found in 89-GHz polarization-corrected temperature (PCT89), 89-GHz polarization difference (PD89), and 150-GHz TBs and that this sensitivity decreased with FLH due to emission from mixed- and liquid-phase particles. The RTM simulation, however, overestimated the AMSR-E PCT89 depressions for nonzero FLH cases. This indicates that microwave retrieval for winter precipitation requires a priori information about FLH and an efficient mixed-phase-particle model for RTM. The relationship between surface precipitation rate and TBs was also influenced by the observed variation of CLWC. The relationship between PCT89 and PD89 is greatly altered in terms of CLWC. Relationship between AMSR-E PCT89 precipitation sensitivity and CLWC estimated from PCT89 and PD89 was qualitatively consistent with those of the RTM simulations. This suggests that CLWC, another important retrieval parameter, can be estimated from PCT89 and PD89.

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.

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

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.