What's New Archive

After spending 8 months under water and ice, two of NOAA’s three Arctic-deployed pop-up floats have successfully surfaced in the Chukchi Sea and are transmitting data on temperature, pressure, photosynthetic active radiation (PAR), and chlorophyll fluorescence. These data are from measurements taken while the float is anchored to the seafloor, while it rises through the water column, and while it is trapped under the ice at the water-ice boundary.  

The two floats were initially deployed in the fall of 2020 by the scientists and crew of NOAA Ship Oscar Dyson. These are part of the 4th cohort of deployments since 2017, and the second cohort deployed in the Chukchi Sea.  The first float to surface has transmitted data from the four months it spent on the seafloor, just over a month of data from when it was trapped under ice, and about half of the photos it took while under ice. The second float has transmitted about five months of data from the seafloor, just over four months of data from under the ice along with the under-ice photos it captured, and 7 days of open ocean sea surface temperature. 

Pop-up floats provide an inexpensive method to explore a unique micro-ecosystem under floating ice. The floats collect ocean health data to help researchers better understand the rapidly changing Arctic ecosystem. They collect data during the ice-covered winter and spring months, a time during which it isn’t possible for researchers to penetrate the ice from above to study the water underneath. The water column data they collect on their rise up from seafloor to surface is essential for researchers to monitor ongoing ecosystem changes in the Arctic, such as watching for harmful algal blooms and documenting biodiversity in the environment. The floats can also help researchers measure the extent of the cold pool, an area of cold water about 30 meters deep that results from melting Arctic ice from the previous season.

NOAA PMEL began development of these floats in 2015. The float is an orange sphere equipped with sensors to measure temperature, pressure, and other ocean conditions as well as cameras to capture under ice imagery. It is deployed during the ice-free summer months and anchors to the seafloor measuring bottom-ocean conditions. It stays here collecting measurements throughout the winter and early spring. It then rises up through the water column at a pre-programmed time, in this case early March to mid-April, capturing data at various depths to create a profile of the water column. The floats are then trapped under ice when it reaches the surface, and will continue collecting data and images of conditions at the water-ice boundary. When the ice melts in mid-May and early June, the floats can emerge fully from the ice to reach the surface and begin transmitting their stored data, while continuing to monitor sea surface temperature. 

Read more about the 2020 pop-up deployments in Arctic Today and on the ITAE website.

Firefighters have reported that Western wildfires are starting earlier in the morning and dying down later at night, hampering their ability to recover and regroup before the next day’s flareup.

A study by NOAA Cooperative Institute at the University of Washington and U.S. Forest Service scientists shows why: The drying power of nighttime air over much of the Western U.S. has increased dramatically in the past 40 years. The paper was published online in July in Geophysical Research Letters.

“Nighttime is an important time in fire management. When fires die down at night it gives firefighters a chance to rest, move equipment and strategize. The problem firefighters are reporting is an unexpected increase in nighttime fire activity,” said lead author Andy Chiodi, a UW research scientist at the Cooperative Institute for Climate, Ocean & Ecosystem Studies and at NOAA's Pacific Marine Environmental Laboratory . “Our findings support that this has been going on over the last 40 years over much, but not all, of the Western U.S.”

Earth’s atmosphere is warming due to climate change, and warming in many places has been greater at night. Warmer night air had been suspected as the culprit altering the daily pattern of wildfire activity, with burns continuing later into the night. The new study, however, shows it’s not just that the night air is warmer, but also a dramatic shift from 1980 to 2019 in its drying power — how much moisture the nighttime air can carry away from the fuels — over much of the Western U.S. This shift is not captured in climate models, and the authors say it could be related to natural long-term cycles rather than to climate change.

“We paid special attention to the change in recent years compared to the conditions seen in the ’80s and ’90s, which is when many of the current firefighters started their careers, and presumably formed their ideas about what normal fire behavior should look like,” Chiodi said. “We tried to quantify the changes that we were hearing about from firefighters.”

Vapor Pressure Deficit 

The study looks at the “vapor pressure deficit,” or the difference between the moisture in the air and the saturation moisture level at that air temperature. This difference is a measure of the air’s drying power.

“In the southern Sierra Nevada, the average summer nighttime vapor pressure deficit for the recent decade was 50% higher than the average in the ’80s and ’90s,” Chiodi said. “I was surprised — it’s unusual to see geophysical data change that dramatically.”

Some of this shift in vapor pressure deficit is happening because warmer nighttime air, caused by climate change, produce higher saturation values. But part of the drying power is happening because the nighttime air in some regions has less moisture, and that effect is not predicted by climate change models, at least this much or in this pattern. The authors find a possible connection to the Pacific Decadal Oscillation, a long-term cycle that can influence inland weather.

“Firefighters had been saying for several years that they feel some fires burn later into the evening than they used to,” said co-author Brian Potter at the U.S. Forest Service’s Pacific Wildland Fire Sciences Laboratory. “We found that in some areas, the amount of water in the air is decreasing, sort of doubling up on the warmer nights. These areas, including where the Snake River Complex and Lick Creek fires are burning right now, are much more likely to have fires burn late into the night.”

The analysis used hourly weather outputs from the European Centre for Medium-Range Weather Forecasts. The recently released hourly reconstructions of historical weather allowed investigation of daily cycles. The next step, Chiodi said, is to further explore the causes of these changes in nighttime vapor pressure deficit. After that, he hopes to connect the atmospheric conditions more directly to fuel moisture and fire behavior.

The other co-author is Narasimhan ‘Sim’ Larkin at the U.S. Forest Service’s Pacific Wildland Fire Sciences Laboratory in Seattle. The research was funded by the U.S. Forest Service through its AirFire research team and by NOAA. Story originally posted by the University of Washington. 

On June 13, scientists aboard the NOAA Ship Ronald H. Brown set out on the West Coast Ocean Acidification Research Cruise to characterize conditions along the West Coast of North America and continue to build a unique time-series of carbon and hydrographic measurements in areas expected to be highly impacted by ocean acidification. Scientists have been collecting samples from CTDs, collecting plankton and water samples for genomics analysis, and conducting the first systematic regional survey of methane gas coming out of the thousands of seeps along the west coast.

The California Current System, running along the North American west coast from British Columbia to Baja California, is a region where seasonal upwelling brings nutrient- and carbon dioxide-rich and oxygen-poor waters to the surface. Increasing levels of carbon dioxide from upwelling and anthropogenic emissions, cause a series of chemical reactions that are ultimately increasing acidity in these waters. Because it is an area with high rates of primary production by phytoplankton, air-sea carbon dioxide exchange, and carbon export to the open ocean and sediments, it is particularly susceptible to the impacts of ocean acidification and hypoxia. Understanding the progression of ocean acidification in coastal areas in the context of these other natural processes is critical for developing management, mitigation, and adaptation strategies.

This 47-day research cruise brings together an international team of scientists from the United States, Canada, Mexico, Finland, and the Netherlands to measure acidity, temperature, oxygen, and chlorophyll from 16 transect lines stretching from British Columbia, Canada to San Diego, California. They also have deployed net tows to sample phytoplankton, zooplankton, and fish to analyze how the marine food web is being affected by acidified waters.

With data collected from this cruise, and previous ocean acidification cruises in this region, scientists are documenting the changing ocean acidification conditions and how they are impacting marine ecosystems against a backdrop of multiple stressors including warming and deoxygenation.  In 2016, measurements from this cruise demonstrated, for the first time, that ocean acidification along the US Pacific Northwest coast is impacting the shells and sensory organs of some larval Dungeness crab and that pteropods sampled near the coasts of Washington and Oregon had shells 37 percent thinner than those in waters further offshore.

With the comprehensive approach taken on this year’s mission- combining detailed physical, chemical and biological measurements - we will not only  better understand how our ocean is changing, but also test what new tools can be used to assess the future of these important marine ecosystems.

“A strong understanding of both the changes in chemistry and marine life allows us to make informed decisions to sustain the ecosystems, communities and industry members along the West coast,” says Libby Jewett, Director of NOAA’s Ocean Acidification Program which funds this research cruise.

Follow along scientists aboard with NOAA’s Ocean Acidification Program’s Twitter, Instagram and Facebook .

NOAA and NASA researchers have found that Earth’s energy imbalance approximately doubled during the 14-year period from 2005 to 2019. Earth's climate is determined by a delicate balance between how much of the Sun's radiative energy is absorbed in the atmosphere and at the surface and how much thermal infrared radiation Earth emits to space. A positive energy imbalance means the Earth system is gaining energy, causing the planet to heat up. The doubling of the energy imbalance is the topic of a recent study, the results of which were published June 15 in Geophysical Research Letters.

Scientists compared data from two independent measurements. NASA's Clouds and the Earth's Radiant Energy System (CERES) suite of satellite sensors measure how much energy enters and leaves Earth's system. In addition, data from a global array of ocean floats, called Argo, enable an accurate estimate of the rate at which the world’s oceans are heating up. Since approximately 90 percent of the excess energy from an energy imbalance ends up in the ocean, the overall trends of incoming and outgoing radiation should broadly agree with changes in ocean heat content.

"The two very independent ways of looking at changes in Earth's energy imbalance are in really, really good agreement, and they're both showing this very large trend, which gives us a lot of confidence that what we're seeing is a real phenomenon and not just an instrumental artifact, " said Norman Loeb, lead author for the study and principal investigator for CERES at NASA's Langley Research Center in Hampton, Virginia. "The trends we found were quite alarming in a sense."

Increases in emissions of greenhouse gases such as carbon dioxide and methane due to human activity trap heat in the atmosphere, capturing outgoing radiation that would otherwise escape into space. The warming drives other changes, such as snow and ice melt, and increased water vapor and cloud changes that can further enhance the warming. Earth’s energy imbalance is the net effect of all these factors. In order to determine the primary factors driving the imbalance, the investigators used a method that looked at changes in clouds, water vapor, combined contributions from trace gases and the output of light from the Sun, surface albedo (the amount of light reflected by the Earth's surface), tiny atmospheric particles called aerosols, and changes in surface and atmospheric temperature distributions.

The study finds that the doubling of the imbalance is partially the result an increase in greenhouse gases due to human activity, also known as anthropogenic forcing, along with increases in water vapor are trapping more outgoing longwave radiation, further contributing to Earth’s energy imbalance. Additionally, the related decrease in clouds and sea ice lead to more absorption of solar energy.

The researchers also found that a flip of the Pacific Decadal Oscillation (PDO) from a cool phase to a warm phase likely played a major role in the intensification of the energy imbalance. The PDO is a pattern of Pacific climate variability. Its fingerprint includes a massive wedge of water in the eastern Pacific that goes through cool and warm phases. This naturally occurring internal variability in the Earth system can have far-reaching effects on weather and climate. An intensely warm PDO phase that began around 2014 and continued until 2020 caused a widespread reduction in cloud coverage over the ocean and a corresponding increase in the absorption of solar radiation.

"It's likely a mix of anthropogenic forcing and internal variability," said Loeb. "And over this period they're both causing warming, which leads to a fairly large change in Earth's energy imbalance. The magnitude of the increase is unprecedented."

Loeb cautions that the study is only a snapshot relative to long-term climate change, and that it's not possible to predict with any certainty what the coming decades might look like for the balance of Earth's energy budget. The study does conclude, however, that unless the rate of heat uptake subsides, greater changes in climate than are already occurring should be expected.

"The lengthening and highly complementary records from Argo and CERES have allowed us both to pin down Earth’s energy imbalance with increasing accuracy, and to study its variations and trends with increasing insight, as time goes on." said Gregory Johnson, co-author on the study and physical oceanographer at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, Washington. "Observing the magnitude and variations of this energy imbalance are vital to understanding Earth’s changing climate."

Read the original articles posted by NASA Langley.