Haruhisa Shimoda

Five years of AMSR-E monitoring and successive GCOM-W1/AMSR2 instrument

Japan Aerospace Exploration Agency (JAXA) has been proposing the Global Change Observation Mission (GCOM). GCOM will consist of two series of medium size satellites: GCOM-W (Water) and GCOM-C (Climate). The mission will take over the Advanced Earth Observing Satellite-II (ADEOS-II or Midori-II). The GCOM-W1 satellite (the first generation of GCOM-W series) was approved by the Space Activities Commission of Japan to proceed to the development phase. Current target of launch date is the beginning of 2012. The Advanced Microwave Scanning Radiometer-2 (AMSR2) is sole mission instrument onboard the GCOM-W1 satellite. Although the simultaneous observation by a microwave scatterometer and AMSR2 is still desired, installation of the scatterometer is not the case at least for the GCOM-W1 satellite. AMSR2 is a successor of the AMSR for the EOS (AMSR-E) provided to the NASA Aqua satellite and AMSR onboard Midori-II with some improvements based on the experiences of AMSR and AMSR-E. They include an improvement of calibration system and an addition of 7.3 GHz channels to help mitigating radio-frequency interference issue. The AMSR-E instrument is still providing continuous data records more than 5-years. Observed brightness temperatures and retrieved geophysical parameters are being widely used for monitoring environmental changes and for applying to the operational applications such as numerical weather forecasting. We expect a long-term continuity by leading the GCOM-W/AMSR2 to the AMSR-E observation.

Status of GCOM-W1/AMSR2 development and science activities

Japan Aerospace Exploration Agency (JAXA) is developing the Advanced Microwave Scanning Radiometer-2 (AMSR2). AMSR2 will be onboard the GCOM-W1 satellite, which is the first satellite of the Japans Global Change Observation Mission (GCOM). The second satellite of GCOM will be GCOM-C1, which will carry the Secondgeneration Global Imager (SGLI). AMSR2 is being developed based on the experience of the AMSR for the EOS (AMSR-E), which is currently in operation on EOS Aqua satellite more than 6-years. The AMSR2 instrument is a dualpolarized total power microwave radiometer system with six frequency bands ranging from 7GHz to 89GHz. Major changes in performance from AMSR-E include the larger antenna diameter of 2.0m for better spatial resolution, additional 7.3GHz channels for mitigating radio-frequency interference, and improvements of calibration system. Engineering model of AMSR2 is being manufactured and tested including performance testing of calibration target in thermal vacuum environment. The GCOM-W1 satellite system finished the preliminary design review before proceeding to Phase-C in June 2008. AMSR2 will observe various water-related geophysical parameters. We expect a long-term continuity by leading the AMSR2 to the current AMSR-E observation that has been accumulating six years of data records. This will contribute to the long-term monitoring of climate variability and daily operational applications. Current target launch year of GCOM-W1 is the beginning of 2012.

Long-term observations of water and climate by AMSR-E and GCOM-W

The Global Change Observation Mission (GCOM) consists of two satellite observing systems and three generations to achieve global, comprehensive, and long-term Earth monitoring. The first satellite of the GCOM-W (Water) series will be GCOM-W1 with the Advanced Microwave Scanning Radiometer-2 (AMSR2) onboard. AMSR2 is a successor of AMSR on the Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR for EOS (AMSR-E) on NASAs Aqua satellite. Basic performance of AMSR2 will be similar to that of AMSR-E based on the minimum requirement of data continuity of AMSR-E, with several enhancements including larger main reflector (2.0 m), additional channels in C-band receiver, and improved calibration system. Development of the GCOM-W1 satellite and sensor system is going quite smoothly. The satellite system is now in Phase-C and finished the CDR No.1 in July 2009. The CDR No.2 is scheduled in autumn 2009 for reviewing the additional items. The AMSR2 instrument is now in Phase-D and the flight model is being manufactured. Retrieval algorithms are being developed by collaboration with principal investigators for the eight standard products and possible research products. Experiences through the AMSR-E research activities and the data themselves can be directly utilized in the AMSR2 algorithm development. AMSR-E continues its observation nearly seven years. Taking over from the AMSR-E observations to GCOM, we will be able to construct over 20-years data set of unique geophysical parameters including all-weather sea surface temperature and soil moisture content. Current target launch year of GCOM-W1 is in Japanese fiscal year 2011.

Status of the GCOM-W and onboard AMSR follow-on instrument

One of the series of satellite for the Global Change Observation Mission (GCOM) is the GCOM-W that will carry the Advanced Microwave Scanning Radiometer (AMSR) follow-on instrument. To keep the continuous observation by the current AMSR for the EOS (AMSR-E) on the Aqua satellite, an earliest launch date is desired. Current proposed launch year is 2010 in Japanese fiscal year. The AMSR-E instrument has been successfully operated for about 4-years and expected to continue providing measurements with high-spatial resolution and in C-band channels that are used to estimate all-weather sea surface temperature and land surface soil moisture. The total dataset period will be over 20-years if the AMSR-E observation can last until the GCOM-W launch. Among the GCOM mission objectives, GCOM-W will focus on the long-term observation of variations in water and energy circulation. In addition, further practical uses including numerical weather forecasting, maritime and meteorological monitoring, and ice applications will be promoted. The AMSR follow-on instrument will be a six-frequency, dual polarized passive microwave radiometer system to observe water-related geophysical parameters. It takes over the basic sensor concept of the AMSR-E instrument with some essential improvements on the calibration system and mitigation of radio-frequency interference (RFI) in C-band channels. Regarding the calibration system, some issues particularly for the warm load target will be investigated and improved based on the AMSR and AMSR-E experiences. Although mitigating the RFI problem is a difficult issue, some preliminary aircraft measurements of anthropogenic radio emissions have performed in Japan and used for assessing the possibilities of sub-band configuration in C-band. Prototyping the several critical components including the above has already started in the last Japanese fiscal year.

Overview of Japanese Earth observation programs

Five programs, i.e. TRMM, AMSR-E, ASTER, GOSAT and GCOM-W1 are going on in Japanese Earth Observation programs. ASTER has lost its short wave infrared channels. AMSR-E stopped its operation, but it started its operation from Sep. 2012. GCOM-W1 was launched on 18, May, 2012 and is operating well as well as TRMM and GOSAT. ALOS (Advanced Land Observing Satellite) was successfully launched on 24th Jan. 2006. ALOS carries three instruments, i.e., PRISM (Panchromatic Remote Sensing Instrument for Stereo Mapping), AVNIR-2 (Advanced Visible and Near Infrared Radiometer), and PALSAR (Phased Array L band Synthetic Aperture Radar). Unfortunately, ALOS has stopped its operation on 22nd, April, 2011 by power loss. GOSAT (Greenhouse Gas Observation Satellite) was successfully launched on 29, January, 2009. GOSAT carries 2 instruments, i.e. a green house gas sensor (TANSOFTS) and a cloud/aerosol imager (TANSO-CAI). The main sensor is a Fourier transform spectrometer (FTS) and covers 0.76 to 15 μm region with 0.2 to 0.5 cm-1 resolution. SMILES (Super-conducting Millimeter wave Emission Spectrometer) was launched on September 2009 to ISS and started the observation, but stopped its operation on April 2010. After the unfortunate accident of ADEOS2, JAXA still have plans of Earth observation programs. Next generation satellites will be launched in 2012-2015 timeframe. They are, GCOM-C (ADEOS-2 follow on), and GPM (Global Precipitation Mission) core satellite. GPM is a joint project with NASA and will carry two instruments. JAXA will develop DPR (Dual frequency Precipitation Radar) which is a follow on of PR on TRMM. Another project is EarthCare. It is a joint project with ESA and JAXA is going to provide CPR (Cloud Profiling Radar). GCOM-C1 will be launched on fiscal 2016, GPM core satellite will be launched on 2014 and EarthCare will be launched on 2015. ALOS F/O satellites are divided into two satellites, i.e. SAR and optical satellites. The first one of ALOS F/O is called ALOS 2 and will carry L-band SAR. It will be launched on fiscal 2013. JAXA is planning to launch follow on of optical sensors on ALOS. GOSAT2 project is going to start and will be launched on 2018.

Overview of vegetation Lidar “MOLI”

Accurate measurements of forest biomass are important to evaluate its contribution to the global carbon cycle. Forest biomass correlates with forest canopy height; therefore, global measurements of canopy height enable a more precise understanding of the global carbon cycle. A vegetation lidar named “MOLI” which is designed to measure accurate canopy height has been studied by the Japan Aerospace Exploration Agency (JAXA) in cooperation with some researchers. MOLI stands for Multi-footprint Observation Lidar and Imager. The feature of MOLI is to set multi-footprints for improving the precision of canopy height, and we can find out whether ground surface is flat or slope because an angle of inclination affects the estimation of canopy height. MOLI is going to be mounted on the Exposed Facility (EF) of the Japanese Experiment Module (JEM, also known as “Kibo”) on the International Space Station (ISS). Now, we are carrying out a feasibility study and some experiments. We introduce an overview and a status of MOLI.

Front Matter: Volume 10423

This PDF file contains the front matter associated with SPIE Proceedings Volume 10423, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

VIIRS spectral sharpening, or solution looking for a problem (Conference Presentation)

The Visible/Infrared Imaging Radiometer Suite (VIIRS) is the NOAA operational follow-on to the Moderate Resolution Imaging Spectrometer on NASA’s Earth Observing System. VIIRS operates on the Joint Polar-orbiting Satellite System which is the now current NOAA low-earth orbit operational Meteorological Satellite system. The VIIRS has Moderate (750 m nadir resolution) and Imaging (375 m nadir resolution) bands, as well as a band with large dynamic range that operates as a 750 m resolution, full swath imaging band in both day and night viewing conditions. This presentation will look at one specific M-band centered at 680 nm and one I-band centered at 640 nm which are nested spectrally, but for which the I-band has an 80 nm bandwidth and the M-band has a 20 nm bandwidth. We will show that an additional band of 60 nm (centered at 630 nm) may be synthesized from these two bands because the trailing edges of the spectral response of these two bands are nearly identical. The synthetic band will have lower radiometric accuracy and is considered most useful for diagnostic rather than specific quantitative objectives. Potential guidelines for the use of this synthetic band are provided also. A coarse uncertainty budget is shown that provides the uncertainty sources unique to the synthetic band, which are in addition to the uncertainties of the input bands. The concept of constructing a synthetic spectral band in this manner is considered an appropriate remote sensing concept only in the context of spectro-radiometric calibration approaches when tunable laser-source, absolute detector based calibrations are provided due to the enhanced calibrations with this class of standard devices. Traditional radiometric calibrations using integrating spheres are not considered sufficiently precise or sufficiently accurate to support computations of this nature. nThis may be thought of as a solution looking for a problem. Then we will show the results of an investigation into applying this solution to the detection of Harmful Algal Blooms (HAB). Laboratory results from the literature are introduced showing that species common to HAB in the Florida USA Gulf Coast have an absorption feature centered near 630 nm. This species is Karenia brevis which is the most common algae in West Florida shelf HABs. HAB outbreaks observed within the 6-year VIIRS dataset will be investigated using this synthesized band to assess the usefulness of this band as another tool for the study of coastal processes.

SNPP VIIRS reflective solar bands on-orbit calibration using the Moon (Conference Presentation)

The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) spacecraft has been on orbit for more than five years. It has been scheduled to view the moon approximately monthly since its nadir door open on November 21, 2011. The scheduled lunar observations have been used to monitor the VIIRS reflective solar bands (RSB) on-orbit gain changes. The VIIRS RSB are primarily calibrated by an onboard Solar Diffuser (SD) panel and an accompanying Solar Diffuser Stability Monitor (SDSM). Due to non-uniformity of the SD degradation, the SD/SDSM calibration may have non-negligible errors, especially for the short wavelength bands. Since lunar surface is very stable, the Moon can be used to provide more reliable on-orbit long-term gain changes of the RSB. The RSB calibration coefficients derived from the lunar calibration are generally consistent with those derived from the SD/SDSM calibration, but clear differences in trend are seen, especially for the short wavelength bands.

The Copernicus Sentinel 4 mission: a geostationary imaging UVN spectrometer for air quality monitoring

Sentinel-4 is an imaging UVN (UV-VIS-NIR) spectrometer, developed by Airbus Defence and Space under ESA contract in the frame of the joint EU/ESA COPERNICUS program. The mission objective is the operational monitoring of trace gas concentrations for atmospheric chemistry and climate applications – hence the motto of Sentinel-4 “Knowing what we breathe”. Sentinel-4 will provide accurate measurements of key atmospheric constituents such as ozone, nitrogen dioxide, sulfur dioxide, methane, and aerosol properties over Europe and adjacent regions from a geostationary orbit (see Fig. 1). In the family of already flown UVN spectrometers (SCIAMACHY, OMI, GOME and GOME 2) and of those spectrometers currently under development (Sentinel-5p and Sentinel-5), Sentinel-4 is unique in being the first geostationary UVN mission. Furthermore, thanks to its 60-minutes repeat cycle measurements and high spatial resolution (8x8 km2), Sentinel-4 will increase the frequency of cloud-free observations, which is necessary to assess troposphere variability. Two identical Sentinel-4 instruments (PFM and FM-2) will be embarked, as Customer Furnished Item (CFI), fully verified, qualified and calibrated respectively onto two EUMETSAT satellites: Meteosat Third Generation-Sounder 1 and 2 (MTG-S1 and MTG-S2), whose Flight Acceptance Reviews are presently planned respectively in Q4 2021 and Q1 2030. This paper gives an overview of the Sentinel-4 system1 architecture, its design and development status, current performances and the key technological challenges.