Research of Precipitation Measuring Mission

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25ER1400

Subject Category: Space Technology

Responsible Representative: Osamu Ochiai, Earth Observation Research Center
Contact Information: Takuji Kubota(kubota.takuji@jaxa.jp)
Members: Tomohiko Higashiuwatoko, Takeshi Masaki, Munehisa K. Yamamoto, Takuji Kubota

Abstract

Calculation of the global rainfall map derived from Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Measurement (GPM) during a period from Decemebr 1997 to March 2023 using the latest GSMaP standard algorithm (V08) and GSMaP Gauge NRT V8 algorithm.

Reference URL

Please refer to https://www.eorc.jaxa.jp/GPM/en/index.html .

Reasons and benefits of using JAXA Supercomputer System

The JSS3 is necessary for calculation of the long-term data which consists of multiple satellites and sensors for the precipitation measurement with earlier computational times for algorithm evaluations, improvements, and long-term production. Because of the complexity of the processing algorithms, strict business progress management, emergency response, detailed user response by the operation side, etc. are required. When we do not use the JSS3, it can be said that reprocessing in a short period cannot be achieved.

Achievements of the Year

The Global Satellite Mapping of Precipitation (GSMaP) is a global precipitation dataset developed under the Global Precipitation Measurement (GPM) mission by integrating observations from multiple precipitation-measuring satellites and geostationary meteorological satellites. Developed by JAXA, GSMaP products are widely used by users around the world. In fiscal year 2021, GSMaP products reprocessed with the latest GSMaP algorithm (Version 8) for the satellite observation period since 2000 were released and are currently in operational use. A major version upgrade of GSMaP is scheduled for August 2026.

In the current fiscal year, long-term processing over several months has been conducted based on algorithm code submitted by the principal investigators responsible for algorithm development, and the results have been fed back to the developers. Figure 1 shows the monthly mean precipitation for July 2014 derived from GPM/GMI observations using the existing algorithm, while Figure 2 shows the corresponding result processed with the next-version algorithm.

In the GSMaP microwave precipitation retrieval algorithm, underestimation of precipitation over land has been recognized as a longstanding issue. The next-version algorithm shows an increase in both rain detection and precipitation amount over land, while precipitation over ocean tends to decrease. These changes are consistent with the intended direction of algorithm improvement, and the effectiveness of the algorithm update has been confirmed (Figure 3).

The ability to perform large-scale data processing rapidly using JSS3 significantly increased the number of trial runs, thereby enabling more efficient progress in algorithm development.

Fig.1: Monthly mean precipitation (mm/day) derived from GPM/GMI observations in July 2014 using the existing algorithm.

Fig.2: Monthly mean precipitation (mm/day) derived from GPM/GMI observations in July 2014 using the improved algorithm.

Fig.3: Difference between Figures 2 and 1 (mm/day). Values smaller than 1mm/day are not shown.

Publications

N/A

Usage of JSS

Computational Information

Process Parallelization Methods: N/A
Thread Parallelization Methods: N/A
Number of Processes: 1
Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.02

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

Computational Resources
System Name	CPU Resources Used (Core x Hours)	Fraction of Usage*2(%)
TOKI-SORA	0.00	0.00
TOKI-ST	101660.48	0.11
TOKI-GP	0.00	0.00
TOKI-XM	0.00	0.00
TOKI-LM	0.00	0.00
TOKI-TST	0.00	0.00
TOKI-TGP	0.00	0.00
TOKI-TLM	0.00	0.00

File System Resources
File System Name	Storage Assigned (GiB)	Fraction of Usage*2(%)
/home	0.00	0.00
/data and /data2	71680.00	0.47
/ssd	0.00	0.00

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	54.89	0.17

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

ISV Software Licenses Used

ISV Software Licenses Resources
	ISV Software Licenses Used (Hours)	Fraction of Usage*2(%)
ISV Software Licenses (Total)	0.00	0.00

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.