Informing and inspiring everyone about California’s underwater world

All Columns

U.S.–Japan space out for watery mission

When I entered NASA’s “Let it Snow” international photo competition, I didn’t expect to win. I only entered because I thought it was required as  part of my climate studies course. Since snow isn't a local weather phenomenon along the beach areas of San Diego, I submitted a photo of drifts of snowlike seafoam washed onto shore. To be honest, it was meant to be tongue-in-cheek. Later, when I discovered that the contest wasn't mandatory, I forgot about it.

But then, a month later I received an email congratulating me on my winning photo, now a permanent fixture on NASA's Global Precipitation Measurement webpage. Intrigued, I decided to find out what was behind the seemingly whimsical contest. Turns out it’s an exciting joint project between the U.S. and Japan that will make for a game-changer in the near future of weather and climate forecasting and understanding.

Water in all its forms, such as precipitation, temperature, humidity, and sea level, is the stuff of life and is the foundation of our ever-changing water-climate system. Certainly, the convoluted movements of water through the atmosphere make weather forecasting a complicated business. But projecting future global climate, predicting regional climate impacts, and providing weather forecasts all depend on a solid understanding of water’s leading role on determining climate.

There is a saying that we can’t do anything about the weather but at least we should want to do everything we can to better predict and track its intentions because forewarned is forearmed. However, at present, we are constantly bombarded with wayward weather reports such that many of us believe we are better weather forecasters than the experts.

After all, there is a finite amount of water circulating the planet so if a deluge is soaking one region, a drought can be predicted elsewhere.

Our experts could do better if they had more resources, including more observational and high-tech atmospheric data. To date, we lack the number of satellites necessary to collect enough observations to track weather as it forms, moves, intensifies, and abates.

This isn’t to say there aren’t many weather satellites already orbiting Earth but these are owned and operated by other countries, and each collects data independent of one another. That’s not terribly efficient because all those data points are set to each country’s own independent standards (connecting observations from one system to another would be akin to trying to standardize a wallet containing dollars, euros, rupees, and sheckles).

Why not standardize the data everyone pulls in, and add even more high-tech equipment to better sample the atmosphere? Everyone would win! After all, there is a finite amount of water circulating the planet so if a deluge is soaking one region, a drought can be predicted elsewhere. How could we make this happen?  

Enter the Global Precipitation Measurement (GPM) mission, a joint undertaking by NASA and the Japan Aerospace Exploration Agency (JAXA), with cooperation from a consortium of international space agencies (such as India and France) presently hosting their own orbiting weather satellites. The mission’s goals are two-fold: provide massively more global rain and snow observations, to be updated every three hours (how long it takes for all the satellites to observe precipitation over the entire globe), and unify those observations to one standard to make them meaningful.

The mission’s first step involves launching a “Core Observatory” research satellite, which will carry the first instruments able to make 3-D measurements of precipitation from space using a combination of active and passive remote-sensing techniques. For the second step, weather data gathered by the constellation of satellites will be filtered through the Core satellite. Since the various weather satellites travel along different orbits, they each provide unique data sets. Thus, the Core will not only be receiving tons of data but standardizing each data set to act as a sort-of Grand Central Station (i.e., the reference standard) for worldwide weather sharing.

What the GPM mission gets us for our money will advance our scientific understanding of Earth's water and energy cycle. More and better data translates to a better understanding of storms, hurricanes, droughts and other extreme weather events and their outcomes (such as floods and landslides). Then there is food security, with improved agricultural crop forecasting and monitoring of freshwater resources. And the high-resolution data collected will complement present cloud and aerosol observations to provide further insights into how human activities are affecting precipitation processes (climate change). Thus, we can expect improved climate models, which will translate to improved regional weather and precipitation forecasts and warnings (a welcome development!).

To date, it has been the Wild West up in the sky in terms of weather satellites but now we are on a (GPM) mission to follow the water. Knowing where and how much precipitation falls globally are vital to our understanding the complexities that make up weather and climate, which impact all life on Earth (seafoam formation being just one remarkable example).

It turns out that NASA’s photo competition was not the least bit frivolous but a clever way to inform the public about the GPM website (to which my image is posted) and invite everyone to access the same Core data as the experts. For more information about the mission's science objectives, visit

— Judith Lea Garfield, naturalist and underwater photographer, has authored two natural history books about the underwater park off La Jolla Cove and La Jolla Shores. Send comments to