Precipitation Processing System (PPS) servers will be down for extended maintenance from Tuesday, September 22nd through Thursday September 24th. During this time the PPS websites, the PMM Publisher API, and the GPM research data server (arthurhou) will be unavailable. The GPM near real-time server (jsimpson) and satellite data collection will not be affected. Click here to learn more.


Getting the Big Picture: Remote Sensing

Submitted by JacobAdmin on Thu, 11/12/2015
Video Embed

A brief animated look at the different types of remote sensing techniques that NASA uses to study the Earth. This video discusses why we need remote sensing to study the Earth, and the differences between active and passive remote sensing from satellites. It also gives examples of different types of data NASA satellites collect about the Earth, and some of the applications of that data.

This video is public domain and can be downloaded in high resolution here.


Active and Passive Remote Sensing Diagram

Diagram illustrating the differences between active and passive remote sensing.
Image Caption
This diagram illustrates the differences between active and passive remote sensing.

TRMM and GPM rely on active and passive instruments to measure the properties of precipitation from space.

Active radars, such as the TRMM Precipitation Radar, transmit and receive signals reflected back to the radar. The signal returned to the radar receiver (called radar reflectivity) provides a measure of the size and number of rain/snow drops at multiple vertical layers in the cloud (Left figure).