Rain - Blog Posts
What Does Two Decades of Rain and Snow Show Us?
You are seeing the culmination of almost twenty years of rain and snow, all at once.
For the first time, we have combined and remastered the satellite measurements from two of our precipitation spacecraft to create our most detailed picture of our planet’s rain and snowfall. This new record will help scientists better understand normal and extreme rain and snowfall around the world and how these weather events may change in a warming climate.
The Most Extreme Places on Earth
Using this new two-decade record, we can see the most extreme places on Earth.
The wettest places on our planet occur over oceans. These extremely wet locations tend to be very concentrated and over small regions.
A region off the coast of Indonesia receives on average 279 inches of rain per year.
An area off the coast of Colombia sees on average 360 inches of rain per year.
The driest places on Earth are more widespread. Two of the driest places on Earth are also next to cold ocean waters. In these parts of the ocean, it rains as little as it does in the desert -- they’re also known as ocean deserts!
Just two thousand miles to the south of Colombia is one of the driest areas, the Atacama Desert in Chile that receives on average 0.64 inches of rain per year.
Across the Atlantic Ocean, Namibia experiences on average 0.49 inches of rain a year and Egypt gets on average 0.04 inches of rain per year.
Global Patterns
As we move from January to December, we can see the seasons shift across the world.
During the summer in the Northern Hemisphere, massive monsoons move over India and Southeast Asia.
We can also see dynamic swirling patterns in the Southern Ocean, which scientists consider one of our planet’s last great unknowns.
Close-up Patterns
This new record also reveals typical patterns of rain and snow at different times of the day -- a pattern known as the diurnal cycle.
As the Sun heats up Earth’s surface during the day, rainfall occurs over land. In Florida, sea breezes from the Gulf of Mexico and Atlantic Ocean feed the storms causing them to peak in the afternoon. At night, storms move over the ocean.
In the winter months in the U.S. west coast, the coastal regions generally receive similar amounts of rain and snow throughout the day. Here, precipitation is driven less from the daily heating of the Sun and more from the Pacific Ocean bringing in atmospheric rivers -- corridors of intense water vapor in the atmosphere.
This new record marks a major milestone in the effort to generate a long-term record of rain and snow. Not only does this long record improve our understanding of rain and snow as our planet changes, but it is a vital tool for other agencies and researchers to understand and predict floods, landslides, disease outbreaks and agricultural production.
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Our Eyes in the Sky See Toxic Waters
Warm summer temperatures often lead to dangerous blooms of phytoplankton in lakes, reservoirs and along our coastlines. These toxin-containing aquatic organisms can sicken people and pets, contaminate drinking water, and force closures at boating and swimming sites.
In this image, a severe bloom of toxic blue-green algae is spreading across the western half of Lake Erie. Taken on July 30, 2019 by the Operational Land Imager on our Landsat 8 satellite, this image shows green patches where the bloom was most dense and where toxicity levels were unsafe for recreational activities. Around the time of this image, the bloom covered about 300 square miles of Lake Erie’s surface, roughly the size of New York City. By August 13, the bloom had doubled to more than 620 square miles. That’s eight times the size of Cleveland.
The dominant organism—a Microcystis cyanobacteria—produces the toxin microcystin, can cause liver damage, numbness, dizziness, and vomiting. On July 29, 2019, the National Oceanic Atmospheric Administration (NOAA) reported unsafe toxin concentrations in Lake Erie and have since advised people (and their pets) to stay away from areas where scum is forming on the water surface.
You can stay informed about harmful algal blooms using a new mobile app that will send you alerts on potentially harmful algal blooms in your area. Called CyAN, it's based on NASA satellite data of the color changes in lakes and other bodies of water. It serves as our eye-in-the-sky early warning system, alerting the public and local officials to when dangerous waters may be in bloom.
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Cape Town was on the verge of running out of water. The South African city of 3.7 million people had suffered years of drought. But after nearly running dry earlier this year, the reservoirs are now rising thanks to rain, conservation efforts, and engineering fixes.
The city’s largest reservoir—Theewaterskloof—holds 40 percent of Cape Town’s water storage capacity, so it's a good barometer for the amount of water available. Natural-color images, captured by Landsat 8, show the change in water levels at Theewaterskloof between July 22, 2017, and July 9, 2018.
Read more HERE.
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Earth: Your Home, Our Mission
We pioneer and support an amazing range of advanced technologies and tools to help us better understand our home planet, the solar system and far beyond.
Here are 5 ways our tech improves life here on Earth...
1. Eyes in the Sky Spot Fires on the Ground
Our Earth observing satellites enable conservation groups to spot and monitor fires across vast rainforests, helping them protect our planet on Earth Day and every day.
2. Helping Tractors Drive Themselves
There has been a lot of talk about self-driving cars, but farmers have already been making good use of self-driving tractors for more than a decade - due in part to a partnership between John Deere and our Jet Propulsion Laboratory.
Growing food sustainably requires smart technology - our GPS correction algorithms help self-driving tractors steer with precision, cutting down on water and fertilizer waste.
3. Turning Smartphones into Satellites
On Earth Day (and every day), we get nonstop "Earth selfies" thanks to Planet Labs' small satellites, inspired by smartphones and created by a team at our Ames Research Center. The high res imagery helps conservation efforts worldwide.
4. Early Flood Warnings
Monsoons, perhaps the least understood and most erratic weather pattern in the United States, bring rain vital to agriculture and ecosystems, but also threaten lives and property. Severe flash-flooding is common. Roads are washed out. Miles away from the cloudburst, dry gulches become raging torrents in seconds. The storms are often accompanied by driving winds, hail and barrages of lightning.
We are working to get better forecasting information to the National Oceanic and Atmospheric Administration (NOAA). Our satellites can track moisture in the air - helping forecasters provide an early warning of flash floods from monsoons.
5. Watching the World's Water
Around the world, agriculture is by far the biggest user of freshwater. Thanks in part to infrared imagery from Landsat, operated by the U.S. Geological Survey (USGS), we can now map, in real time, how much water a field is using, helping conserve that precious resource.
We use the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. Our observations of Earth’s complex natural environment are critical to understanding how our planet’s natural resources and climate are changing now and could change in the future.
Join the celebration online by using #NASA4Earth.
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The 2017 Atlantic Hurricane Season: What We Learned
The 2017 Atlantic hurricane season was among the top ten most active seasons in recorded history. Our experts are exploring what made this year particularly active and the science behind some of the biggest storms to date.
After a period of 12 years without a Category 3 or higher hurricane making landfall in the U.S., Hurricane Harvey made landfall over Texas as a Category 4 hurricane this August.
Harvey was also the biggest rainfall event ever to hit the continental U.S. with estimates more than 49 inches of rain.
Data like this from our Global Precipitation Measurement Mission, which shows the amount of rainfall from the storm and temperatures within the story, are helping scientists better understand how storms develop.
The unique vantage point of satellites can also help first responders, and this year satellite data helped organizations map out response strategies during hurricanes Harvey, Irma and Maria.
In addition to satellites, we use ground stations and aircraft to track hurricanes.
We also use the capabilities of satellites like Suomi NPP and others that are able to take nighttime views. In this instance, we were able to view the power outages in Puerto Rico. This allowed first responders to see where the location of impacted urban areas.
The combined effort between us, NOAA, FEMA and other federal agencies helps us understand more about how major storms develop, how they gain strength and how they affect us.
To learn more about how we study storms, go to www.nasa.gov/Hurricanes.
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How Do Hurricanes Form?
Hurricanes are the most violent storms on Earth. People call these storms by other names, such as typhoons or cyclones, depending on where they occur.
The scientific term for ALL of these storms is tropical cyclone. Only tropical cyclones that form over the Atlantic Ocean or eastern and central Pacific Ocean are called “hurricanes.”
Whatever they are called, tropical cyclones all form the same way.
Tropical cyclones are like giant engines that use warm, moist air as fuel. That is why they form only over warm ocean waters near the equator. This warm, moist air rises and condenses to form clouds and storms.
As this warmer, moister air rises, there's less air left near the Earth's surface. Essentially, as this warm air rises, this causes an area of lower air pressure below.
This starts the 'engine' of the storm. To fill in the low pressure area, air from surrounding areas with higher air pressure pushes in. That “new” air near the Earth's surface also gets heated by the warm ocean water so it also gets warmer and moister and then it rises.
As the warm air continues to rise, the surrounding air swirls in to take its place. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface.
As the storm system rotates faster and faster, an eye forms in the center. It is vey calm and clear in the eye, with very low air pressure.
Tropical cyclones usually weaken when they hit land, because they are no longer being “fed” by the energy from the warm ocean waters. However, when they move inland, they can drop many inches of rain causing flooding as well as wind damage before they die out completely.
There are five types, or categories, of hurricanes. The scale of categories is called the Saffir-Simpson Hurricane Scale and they are based on wind speed.
How Does NASA Study Hurricanes?
Our satellites gather information from space that are made into pictures. Some satellite instruments measure cloud and ocean temperatures. Others measure the height of clouds and how fast rain is falling. Still others measure the speed and direction of winds.
We also fly airplanes into and above hurricanes. The instruments aboard planes gather details about the storm. Some parts are too dangerous for people to fly into. To study these parts, we use airplanes that operate without people.
Learn more about this and other questions by exploring NASA Space Place and the NASA/NOAA SciJinks that offer explanations of science topics for school kids.
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Credits: NASA Space Place & NASA/NOAA SciJinks
Studying Storms from Air and Space
Technology we’ve developed is helping study the movement of storms.
From satellites that can slice through a hurricane with 3-D vision to computer models of gale force winds, scientists now have unprecedented ways of viewing extreme weather.
This August, we’re sending an unmanned aircraft called a Global Hawk to study hurricanes. This mission is called the “East Pacific Origins and Characteristics of Hurricanes,” or EPOCH. It will fly over developing tropical storms to investigate how they progress and intensify.
The three instruments aboard this Global Hawk aircraft will map out 3-D patterns of temperature, pressure, humidity, precipitation and wind speed as well as the role of the East Pacific Ocean in global cyclone formation. These measurements will help scientists better understand the processes that control storm intensity and the role of the East Pacific Ocean in global cyclone formation.
To better understand hurricane formation and intensity, scientists also utilize models and other observations.
Satellites such as our Global Precipitation Measurement Mission, or GPM, and computer models can analyze key stages of storm intensification.
In September 2016, GPM captured Hurricane Matthew’s development from a Category 1 to Category 5 hurricane in less than 24 hours.
Extreme rainfall was seen in several stages of the storm, causing significant flooding and landslides when it passed by Cuba, Haiti and the Dominican Republic.
By combining model and observed data, scientists can analyze storms like never before. They can also better understand how hurricanes and other powerful storms can potentially impact society.
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