Precipitation | Global Satellite Measurements

On Friday February 28, 2014, Japan time, the Global Precipitation Measurement (GPM) Core Observatory was launched by the Japan Aerospace Exploration Agency (JAXA) from the Tanegashima Space Center. The GPM spacecraft will coordinate with an international network of existing and future satellites to measure rainfall and snowfall globally every three hours. The mission will greatly enhance what we know of Earth’s water and energy cycles, aid in the forecasting of extreme weather events, and give us all added benefits in areas where precipitation affects our lives.

Rainfall in the tropics is being measured by the Tropical Rainfall Measuring Mission (TRMM), launched in 1997. It has added important observations of tropical weather systems and hurricanes. The GPM Core Observatory will provide measurements to higher latitudes. GPM will observe from the Antarctic Circle to the Arctic Circle every 3 hours. This graphic compares the ground tracks of the two missions for a 3 orbit time period. GPM, in blue, will add to our data many times over in areal and time coverage compared to TRMM.


Video of the launch from Tanegashima Island

Explanation from NASA of the importance of GPM

GPM will be part of a constellation of satellites from several nations all monitoring precipitation world-wide.


The goal is to better understand the water cycle and energy cycle of the Earth. Water changes states from vapor to liquid to ice. It moves by precipitation, infiltration, transpiration, runoff, and subsurface flow. The gas, liquid and solid states determine the weather, climate, and ecological systems on Earth. Movement between the three phases very strongly affects Earth’s energy budget.


The sun’s heat energy affects the atmosphere and the water and energy cycles. About 25% of the Sun’s energy is used directly to drive atmospheric dynamics. Water adds energy to the atmosphere for the other 75%. Heat causes water to evaporate. It condenses into clouds and rain. Rain releases latent heat into the atmosphere via condensation. That heat drives atmospheric motion of air around the world. TRMM helped create global heat models by measuring rainfall at different altitudes over the tropics. GPM will expand these observations beyond the tropics.

GPM will help understand how precipitation patterns change regionally and globally. More accurate measures of precipitation from the atmosphere to the surface will reduce uncertainties in the water and energy models. Scientists will have more accurate estimates for soil moisture, temperature, and snowpack. Predictions of vegetation cover, weather forecasts, and water/energy models will improve.

Future Launches This Year

Four addition launches this year will add more robustness to the Earth Science monitoring efforts and our understanding of the climate and weather.

1. June – The ISS-RapidScat will monitor ocean winds essential in weather predictions and hurricane monitoring.

2. July – Orbiting Carbon Observatory (OCO)-2 will study atmospheric carbon dioxide from Space.

3. September – SpaceX 5 will deliver Cloud-Aerosol Transport System (CATS), a laser instrument to measure clouds, pollution, dust, smoke, and other particulates in the atmosphere.

4. November – Soil Moisture Active Passive (SMAP) is to measure and map soil moisture, and freeze and thaw conditions to understand Earth’s water, carbon and energy cycles.

These efforts continue the missions designed to better monitor and understand how our atmosphere works and how we can be better stewards for it.


6 thoughts on “Precipitation | Global Satellite Measurements

  1. Very nice overview. We will need to get a better handle of the extreme weather events as accelerated climate change will increase the number and frequency of these events.


  2. We can use all the information we can get, so this will be a very effective coordinated resource. Here in the NW we already rely on satellite data heavily for weather forecasting, since the prevailing winds are off the ocean where there are no surface resources beyond a few buoys. The CATS satellite mentioned here is particularly intriguing, since particulate pollution from China has already begun changing our precipitation in this area. This will be a way to quantify that, among other effects. Thanks for the info about this program.


    • I agree with you about the amount of info. I have a pending post about the aerosols to come out one of these days. That is a significant problem for you.

      Thank you for your comments.


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