Microwave Remote Sensing Group

Microwave Remote Sensing Group

The Microwave Remote Sensing group within CEOSR contributes to NASA’s Precipitation Processing System (PPS) at NASA Goddard. This group works with satellite precipitation retrieval algorithms and develops job-control, archiving, and distribution software along with prototyping visualization software and data analysis products. PPS processes data for NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite and Global Precipitation Measurement (GPM) satellite. The TRMM satellite was launched in 1997 and operated nominally until 2014. The GPM satellite was launched in February of 2014 and will continue to provide global precipitation estimates from space extending from the tropics into mid-latitudes.

Science Logos PPS GPM TRMM


The Microwave Remote Sensing Group members have a broad background with specialties including traditional microwave remote sensing and atmospheric physics, computer science, data management, information technology, data visualization and scientific programming.

The members of the CEOSR Microwave Remote Sensing group are as follows:

Joyce Chou
Owen Kelley
Patrick Kolbe
John Kwiatkowski
Patty McCaughey

Jon Mitchell
Quyen Nguyen
Bala Pillai
Tony Stocker
John Stout

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Among other tasks, CEOSR staff are involved in many aspects of NASA’s global multi-satellite estimate of precipitation, which is generated by an algorithm called IMERG. IMERG stands for “Integrated Multi-satellitE Retrievals for GPM.” The algorithm uses as input passive microwave satellite observations, infrared satellite observations, and various calibration datasets. The CEOSR staff tests new versions of the algorithm and prepares the algorithm for operational use. CEOSR staff monitors the algorithm’s execution, and visualize the algorithms latest estimates in near real time. One such visualization is available on the GPM website as an interactive virtual globe.

In September, 2014, data became publicly available for both instruments of the GPM satellite, the GPM Dual-frequency Precipitation Radar (DPR) and the GPM Microwave Imager (GMI). From February to September 2014, CEOSR staff were involved in the instrument and algorithm checkout period of the GPM satellite. Prior to launch, CEOSR staff were involved in end-to-end testing of the GPM ground system and data processing system. Below are images of a few events that GPM satellite saw during the checkout period.

Hurricane Ita observed by GPM on 9 April 2014

In the above image is shown a GPM overflight of Cyclone Ita a few days before it struck Australia. At the time of this overflight, Cyclone Ita was rapidly intensifying from category 1 to category 4. The GPM radar data on the left shows a “hot tower” cell in the eyewall, a phenomena associated with hurricane intensification. The GPM passive microwave data on the right shows three different views of the storm based on different microwave frequencies. The various frequencies high-light different aspects of the storm’s structure.

Thunderstorms near the South Pole observed by GPM on 31 July 2014

The above image shows a line of thunderstorms in the Southern Ocean. While lightning is relatively rare this close to the poles, it occurs occasionally. The GPM satellite will collected a sample of such storms over the next three years. Such observations may help scientists better understand the severe weather that occasionally effects high latitudes.

Trending of Physical Retrievals

Satellite instrument health and precipitation retrievals can be monitored by trending various quantities over time. We automatically produce trending analysis that provides NASA with information that helps determine the state of the spacecraft, instruments and retrieval algorithms. This information can also be used towards climate studies, particularly in the case of TRMM which has had a 16+ year mission. We routinely trend more than 100 fields from TRMM.

Below is an example of the bright band height from Latitudes 20N to 40N. The ‘bright band’ is an area of mixed phase (water/ice) precipitation around the freezing layer and gets its name from the enhanced echo seen by the radar in that location. The red curve is the mean height of the bright band for all data within a day and clearly shows seasonal variations. The blue curve is the standard deviation within each day. The vertical purple line indicates the change in TRMM orbit in August of 2001 when the spacecraft orbit was changed from 350km to 402km to reduce drag and extend mission life.


Our Work In The Media

NASA Atmosphere’s twitter account: Hurricane Henri (August 2021)
Hurricane: The Anatomy, Episode 1: Predicting the Unpredictable (2014), a documentary featuring Owen Kelley and other scientists
NPR Science Friday: Hurricane Sandy’s CT Scan, and other Vital Images (2 Nov 2012)

Precipitation Processing System (PPS) at NASA Goddard
Global Precipitation Measurement (GPM) Science Team website
Global Precipitation Measurement at @NASA.gov (GPM)