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This web page "JAXA Realtime Rainfall Watch (GSMaP_NOW)" is a quasi-realtime version of "JAXA Global Rainfall Watch (GSMaP_NRT)", which provides global rainfall map 4-hour after observation.

GSMaP_NOW produces rainfall map over the area of geostationary satellite "Himawari", using passive microwave observations that are available within half-hour after observation (GMI, AMSR2 near Japan, and AMSU direct receiving data). Furthermore, half-hour extrapolation of rainfall map toward future direction by using cloud moving vector from the geostationary satellite allows us to estimate "current" rainfall map at every half-hour.

Precaution for use

Please note followings when you use GSMaP_NOW data. Since GSMaP_NOW uses less passive microwave radiometer data as input compared to that of GSMaP_NRT, its data accuracy tends to be worse qualitatively. Further more, GSMaP_NOW at "current hour" is estimated by extrapolating half-hour by cloud moving vector, so data accuracy may become worse.

Early validation result of data accuracy of GSMaP_NOW is available from here.

User Registration for GSMaP_NOW Data

To use data, user registration is needed. If you have already registered as user of the GSMaP_NRT (JAXA Global Rainfall Watch), you can download GSMaP_NOW data from the same ftp server. If you have not registered yet, please make registration from the button below.

  • User Registration

What’s New

Due to our facility maintenance, you may experience difficulty in accessing to web/ftp contents during following period. Sorry for inconvenience.
Period: 01:00-01:30(UTC), Feb. 14
Due to our facility maintenance, you may experience difficulty in accessing to web/ftp contents during following period. Sorry for inconvenience.
Period: 00:50-01:20(UTC), Feb. 10
JAXA have started to provide a new version (product version 04, algorithm version 7) of GPM-GSMaP products.
The GPM-GSMaP new version data are available from January 17, 2017.
Concurrently, existing GPM-GSMaP data are also being reprocessed back to the start of the mission.
GPM-GSMaP algorithm changes from V3 to V4 are described in the release note and the data format.
Please note that the format of the satellite flag is changed.
Our Web and ftp system will be unavailable from 02:45(UTC), Oct. 5 to 03:00(UTC), Oct. 5 due to our facility maintenance. We apologize for any inconvenience.
For the "JAXA Realtime Rainfall Watch" web site, 24-hour rainfall accumulation image and 72-hour rainfall accumulation image are newly added.
We added the GSMaP Reanalysis Product (GSMaP_RNL) and its gauge-calibrated version, which were processed with GSMaP V6 algorithm (the latest one) for the past period before the launch of GPM Core Observatory.
Because archive data before December 2010 were added in this time, you can download data from March 2000 to February 2014.
We added GSMaP_NOW products and updated "JAXA Realtime Rainfall Watch (GSMaP_NOW)" web site.

For GSMaP_NOW data;
The GrADS-readable products are newly added.
Archive data (Rain rate and time flag) of the GrADS-readable products are newly added.

For the "JAXA Realtime Rainfall Watch web site, the full-screen mode or window mode can be selected.
Due to the system maintenance, Web, FTP, and user registration services will be unavailable during the following period.
Date: Apr. 13, 2016, 01:25-3:00(UTC)
Because of system trouble, the image is not displayed past.
We resumed processing from January 19 (JST).
Due to the system failure occurred.
JAXA, we temporarily stop update of our dataset, "JAXA Realtime Rainfall Watch (GSMaP_NOW)", at present.
"JAXA Realtime Rainfall Watch (GSMaP_NOW)" was opened.


Rainfall rate (mm/hr)
Geostationary satellite "Himawari" area
Grid resolution
0.1 degree lat/lon
Temporal resolution
1 hour
Update interval
30 min
Data latency
0-hour after observation


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