Contribution of JAXA&#8217;s Earth Observation Missions to Water Cycle and Climate Studies, Disaster Mitigation, and Operational Applications
Authors: Tachi Kazuo , Furukawa Kinji 
Published: March 2020

&lt;p&gt;&lt;span&gt;&lt;span&gt;Contribution to water cycle and climate studies, disaster mitigation, and various operational applications, including weather forecast, fishery, and agriculture, is a big target of JAXA&amp;#8217;s Earth observation missions. JAXA launched the Greenhouse-gases Observing SATellite-2 (GOSAT-2), which is a successor of the GOSAT satellite, in October 2018. GOSAT series satellites are a joint mission among Ministry of the Environment Government of Japan (MOE), National Institute for Environmental Studies (NIES) and JAXA to provide accurate measurement of greenhouse-gases for researchers and policymakers. Another series of satellites that contribute to water cycle and climate studies is the Global Change Observation Mission (GCOM). It consists of two satellite missions, GCOM-W (Water) and GCOM-C (Climate) and aims to provide comprehensive information of the Essential Climate Variables (ECVs) of atmosphere, ocean, land, cryosphere and ecosystem by combined information of optical and microwave imagers. The GCOM-W satellite carries the Advanced Microwave Scanning Radiometer 2 (AMSR2), a successor of AMSR-E on NASA&amp;#8217;s EOS Aqua satellite, to monitor water-related variables. On the other hand, the GCOM-C satellite carries the Second-generation Global Imager (SGLI) to monitor various parameters related to carbon cycle and energy budget. In December 2019, we started development of the Global Observation SATellite for Greenhouse gases and Water Cycle (GOSAT-GW) that is a joint mission of AMSR2 follow-on (AMSR3) and GOSAT-2 follow-on to be launched in Japanese Fiscal Year (JFY) 2023. AMSR3 will be almost equivalent capability to that of AMSR2 except additional high-frequency channels (166 &amp; 183 GHz) for snowfall retrievals and numerical weather prediction. For water cycle studies, JAXA and NASA led the Global Precipitation Measurement (GPM) mission under international partnership. JAXA provides the Dual-frequency Precipitation Radar (DPR) onboard the GPM core observatory and GCOM-W for the GPM mission to provide high-frequent and accurate global precipitation observation. One of its major outcomes is the Global Satellite Mapping of Precipitation (GSMaP), which is a set of hourly merged-satellite global precipitation products. In June 2019, we have released GSMaP realtime version (GSMaP_NOW) with 0-hour latency over global area, while near-real-time version (GSMaP_NRT) is 4-hour latency. GSMaP is especially used in areas where ground observation capability is not enough, such as isolated islands and developing countries, for heavy rainfall and tropical cyclone monitoring. For land monitoring and disaster mitigation, including flood plain detection, JAXA currently operates the Advanced Land Observing Satellite-2 (ALOS-2) carrying Synthetic Aperture Radar (SAR). Two ALOS series satellites are waiting for launch in near future -- ALOS-3 carrying advanced optical imager to be launched in JFY2020 and ALOS-4 carrying advanced SAR is to be launched in JFY2021. Combination use of multi-satellite and numerical models is one of JAXA&amp;#8217;s targets to expand satellite data utilization in various fields. JAXA collaborates with Japan Meteorological Agency (JMA) in various operational applications. The recent outcome in this collaboration is that JMA will start operational data assimilation of Himawari-8 aerosol products into model for aerosol forecasts in January 2020. Further collaboration with model communities are underway to utilize multi-satellite data into various models for better monitoring and forecasts.&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;