About G-Explorer

The Global Precipitation Measurement Mission (GPM) uses satellites to measure precipitation at earth surface and the vertical structure of storm clouds. Launched by NASA and JAXA in 2014, GPM is an international mission that sets the standard for spaceborne rain and snow measurements, creating a massive, freely available dataset useful for science and operations (see below). The GPM Near-Real-Time Monitor is a web page developed by JAXA that allows to search and find GPM swath data by date. It also displays estimated rain on the surface. One can then download the files from the arthurhouhttps server and use ad-hoc or generic software to display the data. While this sequence works just fine, finding swath data files over a given region and exploring them may result in a tedious task if searching a long window of time.

That motivated the development of G-Explorer, an on-line, simple searching and visualization platform of a subset of GPM data.

In its current version, G-Explorer allows two actions. In the Search-and-find module the user defines a region in a global map, and the system finds all the swaths that partially overlap that region on a given time window. The same module allows to visualize the estimated precipitation at the surface using the data contained in the “light” files (20 Mb) of the type 2A.GPM.DPR.GPM-SLH, download those files, or download the selected “heavy” file (&gt 700 Mb) of the type 2A.GPM.DPR.V9 that contain the full 3D data of each swath. The search is performed using a database created from the light files stored in our server from 2014 to June 2025. We plan to update our database at least twice per year.

In the Display Swath module the user can upload a heavy file to our server, visualize the precipitation at the surface with a 5x5 km2 resolution. Within the swath, the user can select a point and display distance-height cross sections (500 m vertical resolution) of the radar reflectivity (zFinalFactor from KaPR and KuPR) either along or across the swath. One can zoom-in, zoom-out, pan and export the displayed cross section. Note that the full files are not kept in our server.

The first version of G-Explorer was developed in 2025 by a talented group of students from the Computer Science Department of the University of Chile at the request of the Center for Climate and Resilience Science (CR)2. The team is presented here.

We hope G-Explorer will increase the accessibility and usability of GPM data for scientific purposes.All the data used in this was provided by the NASA/Goddard Space Flight Center's and PPS, which develop and compute the DPR data as a contribution to GPM and archived at the NASA GES DISC.We are most grateful to NASA and JAXA for the development and maintenance of the Global Precipitation Measurement Mission.

GPM 101

Precipitation at surface is a key variable in meteorology and climatology, resulting from the fall of hydrometeors (raindrops, ice crystals, snow, and various combinations thereof) that form within storm clouds. The intensity and duration of precipitation determine, among other things, the hydrological response, triggering river floods and inundations in adjacent areas.

Despite its relevance, the spatial distribution of precipitation remains a challenge, especially in regions of complex terrain and/or low density of gauge networks. Ground-based meteorological Radars (Radio Detection and Ranging) are a good alternative but their cost and limited spatial coverage hinder their use in many regions worldwide. That served as one motivation for the Global Precipitation Measurement (GPM) mission, an international network of satellites that provide next-generation global observations of rain and snow. Initiated by NASA and the Japan Aerospace Exploration Agency (JAXA), GPM core satellite was launched in 2014 carrying a Dual-frequency Precipitation Radar (DPR) to measure precipitation from space and serves as a reference standard to unify precipitation.

The DPR instrument consists of a Ka-band precipitation radar (KaPR) operating at 35.5 GHz and a Ku-band precipitation radar (KuPR) operating at 13.6 GHz. Since May 2018, the satellite has been flying a circular, non-sun-synchronous orbit about at 442 km above sea level. Every day, the satellite completes about 15 orbits around the earth from 65°S to 65°N to 65°S, capturing data in a swath of 245 km wide. GPM measures more than 90 variables with a horizontal of 5x5 km2 and vertical resolution of 250 m. Consequently, the data generated by GPM is massive (many, many Terabytes), organized in multiple files (available in HDF format) and available from the NASA's arthurhouhttps server (in honor of Dr. Arthur Hou, the project NASA scientist of GPM).