Space-Earth Sensing

We are conducting various researches in satellite remote sensing technology, data analysis/processing technology, and applications of satellite remote sensing data for global climate/environmental researches by using the data from the instruments with wide range of wavelength and active/passive principles.

Further information → Space-Earth Sensing Web

Data analysis technology

The Earth observations from space had started in 1970's and have been continued by various organizations around the world. Up to now, almost 40-years of data were accumulated for some of the instruments and are being used for detecting a glimpse of the global changes including sea ice decrease in the Arctic Ocean. Improvement of observing sensors in spatial/temporal resolution, enhanced spectral information, increase of the number of satellites by constellation concept, and development of new observation technologies lead the significant glowing diversity and data volume. To properly extract information from such huge dataset, we are conducting researches such as inter-calibration among multiple satellites/sensors and application of machine learning technique including deep learning to such dataset.

Figure above shows an example of rain-area estimation from Himawari-8 infrared brightness temperatures by convolutional neural network trained with ground-based rain radar data.

Remote sensing technology

Developing and improving satellite-borne instruments are one of the essential parts to gain new knowledges of the Earth. We are conducting researches on new sensing technologies required for future missions and sensor calibration methodologies for acquiring high-confidence data. For the future microwave radiometers, larger aperture-size of antenna to improve the spatial resolution and implementation of reduction mechanism of radio-frequency interference (RFI) will be necessary. Our research aims to establish digital-backend microwave radiometers which enable electric beam steering for scanning large antennas and on-board RFI reduction. In addition to the space-borne sensors, ground-based instruments also need to be improved. Recently the Global Navigation Satellite System (GNSS) is being widely used for obtaining location information. The system can also be used for atmospheric and oceanic observation such as water vapor and ocean wind speed by analyzing the delayed or reflected signal. By utilizing the low-cost receiver system, we are investigating the construction of dense observation network.

Figure left shows RFI effects in AMSR2 C-band channels over the North America. Figure right shows NASA's SMAP satellite, which realized the rotating scan system with light-weighted 6m antenna.

Monitoring Earth's environment

Satellite observations, which have unbiased and periodical coverage of the Earth, have been providing indispensable data for global climate and environment monitoring. With the spatial and temporal analyses of various satellite dataset, we are conducting global environment researches particularly focused on the atmospheric science such as understanding the global water cycle and cloud-precipitation systems. Satellite measurements have been playing essential roles in various areas including daily weather forecast and yellow-dust monitoring. However, such best practices are still limited. This is mainly due to the information mismatch between satellite data and end-users' requirements such as in information quality and spatial/temporal resolution. Our researches are trying to resolve such mismatch to promote social implementation of satellite-based applications.

Comparison between monthly sea-surface salinity from NASA's Aquarius and flesh water flux from microwave radiometers data.