RAIN-Global

Regional Animations of IMERG in Near-realtime - Global Edition:
RAIN-Global is the interactive, 3D global version of RAIN, a web interface that serves 7-day animations of precipitation rates and accumulations from IMERG data, as well as cloudiness from geosynchronously observed IR data. Animations are updated daily for the week ending on the prior day. Use your mouse or trackpad to navigate around the globe or use the controls on the left to "fly to" a region, country, or city of interest. Select from a list of recent dates to view precipitation estimates for the week ending on that date.

Technical details:
RAIN-Global loads high-resolution animations of IMERG data that are pre-rendered with a combination of Python and Linux command-line tools on PPS's servers. The animations are then loaded into the three.js framework on the front-end to render them onto an interactive sphere and annotate them. Rendering high-resolution (4k and higher) videos onto a sphere is inherently resource-intensive, so each user's experience will be different based on their hardware, OS, and browser. Modern hardware tends to improve performance. Browser performance tends to be best in Chrome, followed by Safari and Edge, while performance in Firefox may not be optimal. On any hardware/software setup, if the tool is running slower than the specified frame rate, a pop-up will appear with suggestions to reduce the system load and improve performance. This tool is intended to be used for exploratory data analysis and not for research or operations. Animations and images are updated on a "best effort" basis.

FAQs:
Q: Why do the clouds abruptly cut off at high latitudes?
A: This tool uses the NOAA CPC IR 4km half-hourly dataset, which is also used as an input to IMERG, to estimate cloudiness. The CPC IR dataset covers between 60°S and 60°N latitude.
Q: What are the horizontal lines that occasionally show up in the clouds?
A: To cover gaps in the IR data, each half-hourly file is interpolated in post-processing. This has the unfortunate side effect of covering occasional missing swaths, which results in a distracting set of horizontal lines. We are investigating ways to improve this in future versions of RAIN.

Acknowledgements:
The developer acknowledges helpful contributions in 3D rendering from the threejs community (e.g., the panoglobe project), and in UI/UX design from others in the Earth data visualization community (e.g., earth.nullschool.net), which allowed this tool to be built in a modern, interactive format. Colors are selected from www.colorbrewer2.org. The Earth surface image is a modified version of the 2004 Blue Marble image from NASA's Earth Observatory. Owen Kelley (PPS/GMU; Research Scientist) and George Huffman (GSFC; GPM Project Scientist) provided helpful feedback on earlier versions of the animations. Erich Stocker (PPS Manager) suggested the idea of an interactive sphere with animated IMERG data and provided helpful UI/UX feedback. The IMERG algorithm development team (George J. Huffman, David T. Bolvin, Robert Joyce, Owen A. Kelley, Eric J. Nelkin, Jackson Tan, Daniel C. Watters) and partners (Sarah Ringerud, David Wolff, and Yalei You) provided additional helpful feedback.

Administrative:
Curator/developer: Jason West
NASA Official: Erich Stocker
Last Updated: 2024-12-05
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