Water is essential for life on the Earth, and the supply of this precious liquid is constantly being recycled through energy from the sun. This process is known as the hydrologic cycle, and through it water is continuously exchanged between the land, the atmosphere, and the oceans. Precipitation in its various forms is critical to sustaining life and keeping this system going. In order to gain a better understanding of the Earth’s water and energy cycles, the National Aeronautics and Space Administration (NASA) has begun the Global Precipitation Measurement (GPM), an international satellite mission to provide advanced precipitation measurements.
NASA, in conjunction with the Japanese Aerospace Exploration Agency (JAXA) launched the GPM Core Observatory on February 27, 2014, and this satellite is providing global observations of rain and snow every three hours. From its orbit at an altitude of 253 miles, the GPM is surveying weather worldwide from the Arctic Circle to the Antarctic Circle, circling the globe once every 93 minutes. The satellite is working to unify weather data in cooperation with other satellites from major countries like France and India. The data from the satellite can then be used to measure when, where, and how much it rains and snows on the Earth. The GPM is the descendant of NASA’s Tropical Rainfall Measuring Mission (TRMM) in 1997 which measured moderate to heavy rainfall in tropics.
The GPM is equipped with two specialized instruments in order to measure rain and snow. The GPM Microwave Imager (GMI) captures the intensity of precipitation and detects horizontal patterns through clouds. It utilizes different microwave frequencies to observe energy from different types of precipitation. This means that the GMI can detect everything from light to heavy rain and falling snow. Moreover, the GMP’s Dual-frequency Precipitation Radar (DPR) gives 3-D data about precipitation particles based upon the reflected energy that these particles emit. The DPR can not only deduce the size of these particles but also bring an improved understanding of a storm’s physical attributes and features.
The purpose behind the Global Precipitation Measurement is to gain more insight into the Earth’s water and energy cycle as well as get a clearer picture of how weather and climate impact the environment. Knowing how much rain and snow falls on a specific location can help scientists and researchers learn more about natural disasters, the availability of fresh water, the impact of the water cycle on agriculture, and climate change. NASA also hopes the data provided by the GPM mission will bring many societal benefits including the greater capability to predict extreme weather events and hurricanes, better monitoring and managing of freshwater resources, and the improved forecast of natural hazards like droughts.
The image shows rain rates across a 550-mile (885 kilometer) wide swath of an extra-tropical cyclone observed off the coast of Japan on March 10, 2014. Red areas indicate heavy rainfall, while yellow and blue indicate less intense rainfall. In the northwest part of the storm in the upper left of the image, the blue areas indicate falling snow.
Ultimately, NASA’s Global Precipitation Measurement mission is a giant leap forward to better comprehend the role of precipitation in the Earth’s water cycle and weather patterns. Of course, weather patterns and the availability of precipitation in different areas of the globe have a profound impact upon the life found there. Water is vital for life on the planet, and the GPM might be able to help us better appreciate the critical role it plays in sustaining our world.
