Graeme Stephens is principal investigator of NASA’s CloudSat Mission. CloudSat is a satellite designed to investigate how clouds affect Earth’s water cycle – that is, the movement of water on, in, and above the Earth.
Graeme Stephens: We’re really beginning to understand the water cycle of our planet at a level that’s important to make predictions about how this water cycle might change.
CloudSat is equipped with radar that is 1,000 times more sensitive than weather radar. CloudSat’s radar can detect the tiny particles of liquid water and ice that make up clouds, which other satellites can’t see. It orbits the Earth along with NASA’s Aqua satellite, and their data is often combined to make unique and important observations, said Stephens.
Graeme Stephens: We can actually use the observations of CloudSat to basically weigh clouds, and work out how much rain is in the clouds.
Stephens said that scientists want to know how much water is suspended in the atmosphere, and how it converts into rainfall. He said that’s important because climate scientists try to accurately predict how global warming might alter future precipitation.
Graeme Stephens: We find, for example, that the conversion of cloudwater to rainwater is much slower than expected, and much slower than is predicted in climate models.
Stephens said that these findings could reshape the way climate models are created.
Graeme Stephens: These observations are truly unique. And this has been a unique period in Earth observation with this constellation of satellites.
CloudSat is part of what NASA calls a “constellation” of satellites, orbiting the planet together. Dubbed the “A-Train,” these satellites are intended to improve scientific understanding of the climate system and the potential of climate change. The other satellites include Aqua, Aura, Calypso and PARASOL. Stephens explained the usefulness of this constellation.
Graeme Stephens: Cloudsat makes the measurements from this radar, and we use measurements from Aqua from other sensors. We tie them together, and that gives us an absolutely unique way of observing the Earth’s atmosphere, and the processes that shape the flow of water through the atmosphere.
He added that clouds are one of the most complicated aspects of studying the atmosphere.
Graeme Stephens: Clouds are a lot more complicated than carbon dioxide in the atmosphere because they affect sunlight, they affect infrared radiation and the greenhouse effect. These effects are very complicated and in many ways, they compensate each other. It’s been a puzzle as to what clouds really do. The observations we’ve had over last 20 to 30 years, global observations, weren’t precise enough to give us clues as to how greenhouse effects of clouds might compensate albedo effect on clouds – that is, how sunlight is reflected from them.
Stephens said that when scientists learn how clouds interact with other forces in the atmosphere, models predicting future climate will become much more accurate.
Our thanks today to NASA’s Aqua Mission, improving our knowledge of our home planet through satellite observations.
Before I retired I was a staff engineer at the NSCL lab so I am not a crackpot but I do have a question that the mainstream seems to be overlooking. The question is about the temperature gradient that tilts toward the troposphere-stratosphere boundary from both above and below. The huge amount of energy being emitted by water vapor crystallizing there causes that place to be the coldest place in the atmosphere. It must be caused by the emitting of photons of about 18 um wave length for each vapor molecule that is being extinguished because that wavelength is both the vapor sublimation energy per particle and the gap from the top of the waters infrared window (8 um) to its bottom (14 um). Energies in that range are illegal. Water vapor does not go above the cold height and conditions there seem right for stimulated or spontaneous emittion of such photons. Do you have equipment to see that IR selectively over the 10 to 20 um range.
I’m wondering how many times, if at all, the water cycle has completed a full cycle, in human history?
How much water has the human population consumed? Enough that waste emissions have flowed into an ocean, evaporated, and rained back down to a source river or lake, to be consumed again?
Charts on the internet show that fresh water is but 3% of total water and but 0.3% of that is surface water.
Further, as we understand more about clouds, we may find that water’ time in the cloud segment of its cyclical journey may be longer than we first thought. As such, it’s possible that clouds are a station during which a process of sterilizing is ongoing. Evaporation leaves particles (salts, etc) in the ocean’s basins while H2O as vapour rises and condenses into clouds. There, some process occurs in which the sun’s rays react with the water in the clouds to burn away impurities that rose with the vapour, before that cleansed water rains down to provide fresh water for earth’s inhabitants to consume?
Keeping in mind that nature itself had a system for dealing with sewage sludge before humans built sanitation stations, right?
However, if we have yet to complete a cycle, perhaps we have not yet begun to consume water that had been previously consumed by the ancients…?
Thanks for any consideration of the above.
instead of looking up to understand we first must take care of what we all live upon. It’s high time that issues such as nuclear waste which was dumped into under water cavnerns in the artic, which are now leaking and also entering the Earths water supply should be retrieved and made safe. Sewage treatment plants must become a priority to those countries which now just pump it into lakes rivers streams and the Ocean which recives it all. Before we look to understand the clouds we must repair the cloudy water, right here on Earth.
Water is always on the move. Rain falling where you live may have been water in the ocean just days before. And the water you see in a river or stream may have been snow on a high mountaintop.
Water can be in the atmosphere, on the land, in the ocean, and even underground. It is recycled over and over through the water cycle.
We human all need water to survive. No matter who you are or how famous you are, you still need water to survive, even the most renown personalities like Ophra, Obama and Amanda Seyfried they all need water to survive.