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Map of the tropical Pacific showing the positions of DART buoys operated by NOAA and international partners as well as saildrone 1065 and 1066 relative to the Hunga Ha’apai Volcano located in the Pacific island nation of Tonga, which is an archipelago consisting of more than 170 islands.
On January 15, 2022, the Hunga Tonga-Hunga Ha’apai volcano erupted off the coast of Tonga in the South Pacific Ocean, generating a tsunami and triggering tsunami alerts around the world. Most tsunamis are commonly caused by earthquakes and only about 5% of tsunamis are generated from volcanic activity (ITIC), making this a rare event captured by NOAA’s observing instruments.
Buoys and Saildrone uncrewed surface vehicles additionally recorded an air pressure wave associated from the eruption. The pressure wave from the volcano explosion was detected as far as the Mediterranean Sea and traveled about 312 meters/second (697 miles per hour) and circled the Earth three times before dissipating. The Krakatau eruption in 1883 was the last event of such scale. Krakatau produced similar air pressure waves and a devastating tsunami that claimed the lives of ~36,000 people and the destruction of hundreds of coastal towns and villages.
Deep-ocean Assessment and Reporting of Tsunamis (DART) systems are strategically deployed by NOAA and international partners around the Pacific Ocean to detect tsunami waves and send data in realtime to tsunami warning centers. These systems recorded the propagating tsunami across the Pacific and prompted expansion of the tsunami alerts for many coastlines in the Pacific. Those warnings may have saved lives at many coastlines that were later flooded by the waves, some as far as the Pacific coast of Peru.
Along with the tsunami wave amplitudes measured by the DART system, the atmospheric pressure wave associated with a shock-wave emanating from the volcano explosion was measured. The air pressure signal detected by weather station buoys is the leading signature before the tsunami wave train and may provide clues for the mechanism of this unusual tsunami generation. However, given that the pressure signal mixed with the tsunami amplitudes in the data, high-resolution air pressure measurements are needed to decipher the DART tsunami records.
Coincidentally, two NOAA-Saildrone drones were approximately 3500 nautical miles (~4028 miles) away from the eruption, the distance to drive between Anchorage, Alaska and Miami, Florida, in the eastern tropical Pacific Ocean. The two drones are part of a 6-month, ongoing Tropical Pacific Observing System (TPOS) mission targeting the eastern tropical Pacific hurricane genesis region and El Niño Southern Oscillation (ENSO) development. The two drones were able to detect an atmospheric pressure jump in high-resolution measurements, capturing crucial information associated with the remote volcanic activity in an observationally-sparse region of the ocean for post-analysis with the DART tsunami records.
The phenomena recorded in the data is unique and additional research and development is needed to accommodate these types of tsunami events in the model used to forecast tsunami events. PMEL tsunami researchers are analyzing the data from the various platforms to get a better understanding of this rare event.
PMEL has also previously studied the dynamics of a smaller scale eruptive activity of this volcano using acoustic data and will uncover and analyze additional acoustic data from hydrophones deployed across the Pacific when they are recovered later this year.
Read more on the TPOS 2021 Saildrone Mission on the blog page.
More about the event can be found on the PMEL Tsunami Research group events page.
Saildrone departing Alameda, CA to study hurricane genesis and ENSO in eastern Pacific Ocean. Photo Credit: Saildrone, Inc.
As the western U.S. experiences record shattering heat waves, mega droughts and the eastern tropical Pacific started its 2021 hurricane season with the earliest tropical storm (Andres) on record going back to the early 1970s, two Uncrewed Surface Vehicle (USV) saildrones were launched on July 23, 2021 from Alameda, CA on a research mission to the eastern tropical Pacific.
The eastern tropical Pacific is a key region for hurricane genesis and El Niño Southern Oscillation (ENSO) development. The ENSO cycle not only modulates hurricane genesis in the eastern tropical Pacific and the tropical Atlantic, but also affects the global marine ecosystem and weather patterns on land. The hurricanes and tropical cyclones generated in the eastern tropical Pacific, whether or not they make landfall, control the critical source of moisture for rainfall, especially over western North America.
This region, however, is a gap in the Tropical Pacific Observing System (TPOS). The two saildrones enroute to the eastern tropical Pacific, will test how USVs may be used to address gaps in the present TPOS. The 150-day mission will target several phenomena including:
- Air-sea interactions and convective development in the eastern Pacific hurricane genesis region
- Air-sea interactions, including carbon dioxide outgassing, in the equatorial upwelling zone
- Wind convergence in the southeastern Inter-Tropical Convergence Zone (ITCZ) between 2°S and 5°S, often referred to as “the double ITCZ” region due to common biases of this phenomenon in models
- Air-sea interactions in the frontal zone north of the cold equatorial upwelling; and
- Contrasting subtropical and tropical oceanic and atmospheric states in the eastern Pacific.
The mission is funded in part by NOAA Office of Marine and Aviation Operations (OMAO), NOAA Global Ocean Monitoring and Observing Program (GOMO), and NOAA National Oceanographic Partnership Program (NOPP) bringing together partners across NOAA, universities, and industry, along with international partners from Mexico and France. Read more about the mission on PMEL's Ocean Climate Stations page.
As the western U.S. experiences record shattering heat waves, mega droughts and the eastern tropical Pacific started its 2021 hurricane season with the earliest tropical storm (Andres) on record going back to the early 1970s, two Uncrewed Surface Vehicle (USV) saildrones were launched on July 23, 2021 from Alameda, CA on a research mission to the eastern tropical Pacific.
The eastern tropical Pacific is a key region for hurricane genesis and El Niño Southern Oscillation (ENSO) development. The ENSO cycle not only modulates hurricane genesis in the eastern tropical Pacific and the tropical Atlantic, but also affects the global marine ecosystem and weather patterns on land. The hurricanes and tropical cyclones generated in the eastern tropical Pacific, whether or not they make landfall, control the critical source of moisture for rainfall, especially over western North America.
This region, however, is a gap in the Tropical Pacific Observing System (TPOS). The two saildrones enroute to the eastern tropical Pacific, will test how USVs may be used to address gaps in the present TPOS. The 150-day mission will target several phenomena including:
- Air-sea interactions and convective development in the eastern Pacific hurricane genesis region
- Air-sea interactions, including carbon dioxide outgassing, in the equatorial upwelling zone
- Wind convergence in the southeastern Inter-Tropical Convergence Zone (ITCZ) between 2°S and 5°S, often referred to as “the double ITCZ” region due to common biases of this phenomenon in models
- Air-sea interactions in the frontal zone north of the cold equatorial upwelling; and
- Contrasting subtropical and tropical oceanic and atmospheric states in the eastern Pacific.
The mission is funded in part by NOAA Office of Marine and Aviation Operations (OMAO), NOAA Global Ocean Monitoring and Observing Program (GOMO), and NOAA National Oceanographic Partnership Program (NOPP) bringing together partners across NOAA, universities, and industry, along with international partners from Mexico and France. Read more about the mission on PMEL's Ocean Climate Station page.
Saildrone uncrewed surface vehicles (USVs), like the one pictured here, made measurements of atmospheric cold pools in remote regions of the tropical Pacific. Credit: Saildrone, Inc.
Atmospheric cold pools over the tropical oceans produce large changes in air temperature and wind speed in the planetary boundary layer. But how they affect the larger atmospheric circulation is not clear. Cold pools are pockets of air cooler than the surrounding environment that form when rain evaporates under thunderstorms. These relatively dense air masses, ranging between 10 to 200 kilometers in diameter, lead to downdrafts that, upon hitting the ocean surface, produce temperature fronts and strong winds that impact the surrounding environment. To understand the role of cold pools in tropical convection, scientists need detailed measurements of these events; however, observations in hard-to-reach ocean locations have been lacking.
Uncrewed surface vehicles, or USVs, could be a solution. In a new study published in Geophysical Research Letters, scientists from the University of Washington and NOAA’s Pacific Marine Environmental Laboratory describe the use of Saildrone USVs, wind-propelled sailing drones with a tall, hard wing and solar-powered scientific instruments. Over three multi-month missions between 2017-2019, ten USVs covered over 137,000 kilometers and made measurements of over 300 cold pool events, defined as temperature drops of at least 1.5 degrees Celsius in 10 minutes. In one case, four USVs separated by several kilometers captured the minute-by-minute evolution of an event and revealed how the cold pool propagated across the region.
The Saildrone USVs measured variations in air temperature, wind speed, humidity, pressure, and sea surface temperature and salinity. Analysis of these variables revealed key features of cold pool events, including how much and how quickly air temperatures dropped, how long it took for wind speeds to reach their peaks, and the dynamics of sea surface temperature changes. The results can be used to evaluate mathematical models of tropical convection and explore more questions, like how gusts at cold pool fronts affect air-sea heat fluxes.
These missions are part of a larger effort to enhance the Tropical Pacific Observing System (TPOS) to improve long-term weather forecasts and better understand local and regional implications of global phenomena such as El Niño Southern Oscillation (ENSO), hurricanes, typhoons and marine heatwaves (e.g. the “Blob”). An international team of scientists are working to rethink and refine the TPOS to build a more effective, modern and robust observing system to meet the observational, experimental, and operational needs of today and the future.
Story modified from Eos Original Story posted on July 6, 2021.
Satellite sea surface temperature departure for October 2015 over the Pacific. Orange-red colors indicate above normal temperatures, indicative of an El Niño condition. The 2015-16 El Niño was the first extreme El Niño of the 21st century and among the three strongest El Niños on record. Credit: NOAA National Environmental Satellite, Data, and Information Service (NESDIS)
The El Niño Southern Oscillation (ENSO) in the Pacific Ocean has major worldwide social and economic consequences through its global scale effects on atmospheric and oceanic circulation, marine and terrestrial ecosystems, and other natural systems. It is the most dramatic year-to-year variation of the Earth’s climate system, affecting agriculture, public health, freshwater availability, power generation, and economic activity in the United States and around the globe. Ongoing climate change is projected to significantly alter ENSO’s dynamics and impacts.
The future of ENSO is the subject of a new book published by the American Geophysical Union. With 21 chapters written by 98 authors from 58 research institutions in 16 countries, the volume covers the latest theories, models, and observations, and explores the challenges of forecasting El Niño and La Niña. The book, “El Niño Southern Oscillation in a Changing Climate” was published online on November 2.
“This is the first comprehensive examination of how ENSO, its dynamics and its impacts may change under the influence of rising greenhouse gas concentrations in the atmosphere,” said Michael McPhaden, senior scientist with PMEL's Global Tropical Moored Buoy Array, and co-editor of the new volume. Two other co-editors are from Australia: Agus Santoso, a scientist with the University of New South Wales, and Wenju Cai, a researcher with the Commonwealth Scientific and Industrial Research Organisation, also known as CSIRO.
The new book, three years in the making, tracks the historical development of ideas about ENSO, explores underlying physical processes and reveals the latest science on how ENSO responds to external factors such as climate phenomena outside the tropical Pacific, volcanic eruptions, and anthropogenic greenhouse gas forcing.
How are ENSO impacts likely to evolve in the coming decades?
“Extreme El Niño and La Niña events may increase in frequency from about one every 20 years to one every 10 years by the end of the 21st century under aggressive greenhouse gas emission scenarios,” McPhaden said. “The strongest events may also become even stronger than they are today.”
In a warming climate, rainfall extremes are projected to shift eastward along the equator in the Pacific Ocean during El Niño events and westward during extreme La Niña events. Less clear is the potential evolution of rainfall patterns in the mid-latitudes, but extremes may be more pronounced if strong El Niños and La Niñas increase in frequency and amplitude, he said.
Some ENSO impacts are already being amplified, such as the extensive coral bleaching and increases in tropical Pacific storm activity observed during the 2015-16 El Niño. ENSO is expected to impact tropical cyclone genesis in the future as it does today in the Atlantic, Pacific and Indian Oceans, but precisely how is still an open question.
Read more on the NOAA Research feature and AGU highlight.
To learn more about El Nino and La Nina and the research PMEL does, visit https://www.pmel.noaa.gov/elnino/pmel-research-activities
41 scientists from PMEL, including scientists from NOAA's cooperative institutes at the University of Washington's Joint Institute for the Study of the Ocean and Atmosphere (JISAO) and Oregon State University's Cooperative Institute for Marine Resources Studies (CIMRS), the National Research Council, graduate and undergraduate students are heading to the Ocean Sciences Meeting in San Diego to share their current research. Talks and posters cover a range of topics include saildrone research, ocean observing systems, marine heatwaves, Arctic, acoustics, Deep Argo, genetics and genomics, El Nino, hydrothermal vents, methane, nutrients, technologies, ocean carbon and data management.
The 2020 Oceans Science Meeting is the flagship conference for the ocean sciences and the larger ocean-connected community. As we approach the UN Decade of Ocean Science for Sustainable Development, beginning in 2021, it is increasingly important to gather as a scientific community to raise awareness of the truly global dimension of the ocean, address environmental challenges, and set forth on a path towards a resilient planet. The meeting is co-sponsored by the American Geophysical Union (AGU), the Association for the Sciences of Limnology and Oceanography (ASLO), and The Oceanography Society (TOS).
PMEL research groups that will be present at the conference are: Acoustics, Arctic including Innovative Technology for Arctic Exploration, Climate-Weather Interface, Earth-Ocean Interactions, EcoFOCI, Engineering, Genetics and Genomics, Global Tropical Moored Buoy Array, , Large Scale Ocean Physics, Ocean Carbon, Ocean Climate Stations, Pacific Western Boundary Currents, and Science Data Integration Group.
The Saildrone is an autonomous sailing drone currently being explored as a tool to provide high quality oceanic and atmospheric observations (Photo Credit: Saildrone, Inc.).
This week, four saildrones departed from Hawaii on the second mission to the equator in an effort to improve the Tropical Pacific Observing System (TPOS). NOAA forecasts a 50-55% chance of a weak El Niño developing during September - November 2018, increasing to 65-70% chance during winter 2018-19. The second saildrone mission will thus capture ocean and atmospheric data during this developing El Niño, including changes in ocean temperature, winds, currents and ocean carbon dioxide concentrations.
During the first mission in late 2017-early 2018, La Niña conditions were present. Strong currents and low winds on the equator made navigation challenging. This year, two of the four saildrones have been outfitted with larger, more efficient sails, making them faster and more capable in low wind-strong current environments.
This mission is part of a series of saildrone missions to the tropical Pacific, focusing on how this new technology could best be used within the TPOS to improve longterm weather forecasts.
PMEL began a partnership with Saildrone, Inc. in 2014 to develop the unmanned surface vehicles for collecting high quality oceanic and atmospheric observations. PMEL's Ocean Climate Stations group has been working together with PMEL engineers and Saildrone, Inc. since 2016 to install sensors on the drones with equivalent or better quality than those currently used on TAO moorings for air-sea flux measurements.
Follow the TPOS Saildrones’ progress at: https://www.pmel.noaa.gov/ocs/ocs-saildrone-mission-blog-tpos-mission-2
Image of the Willamette River in Portland, OR where the Ocean Sciences Meeting will take place.
More than 50 PMEL scientists, including scientists from NOAA, University of Washington's Joint Institute for the Study of the Ocean and Atmosphere (JISAO), Oregon State University's Cooperative Institute for Marine Resources Studies (CIMRS) and the National Research Council, will present a talk or share a poster on their research at the 2018 Ocean Sciences Meeting in Portland, Oregon February 12-16, 2018. PMEL research groups that will be present at the conference are: Acoustics, Arctic, Earth-Ocean Interactions, EcoFOCI, Engineering, Global Tropical Moored Buoy Array, Innovative Technology for Arctic Exploration, Large Scale Ocean Physics, Ocean Carbon, Ocean Climate Stations, Pacific Western Boundary Currents, Science Data Integration Group, Thermal Modeling and Analysis Project
28 talks will present research on ocean carbon, ocean acidification, ocean observing systems, Arctic research including the Distributed Biological Observatory and Arctic Marine Pulses (AMP), ENSO, MJO, hydrothermal vents, Saildrone research, air-sea interactions, SOCCOM, and ocean mixing. 26 posters will be up during the poster sessions and highlight research in the Arctic, hydrothermal vents, acoustics, methane bubbles and hydrates, Saildrone, Oculus Coastal Glider, ocean carbon, deep ocean temperatures, glider research in the Solomon Sea, and ocean acidification and hyopxia.
PMEL staff will also be chairing sessions and workshops on:
- El Nino-Southern Oscillation (ENSO) Diversity, Predictability, and Impacts
- Western Pacific and Indonesian Sea Circulation and Its Environmental and Climatic Impacts
- New Platform and Sensor Technologies: Advancing Research, Readiness, and Transitioning for Sustained Ocean Observing of Essential Ocean Variables
- Methane from the Subsurface Through the Bio-, Hydro-, and Atmosphere: Advances in Natural Hydrate Systems and Methane Seeps in Marine Ecosystems
- Cascadia Margin methane seep and hydrates to share results and coordinate future work
The 2018 Ocean Sciences Meeting is co-sponsored by the American Geophysical Union (AGU), the Association for the Sciences of Limnology and Oceanography (ASLO), and The Oceanography Society (TOS). The meeting is an important venue for scientific exchange across broad marine science disciplines. Sessions will include all aspects of oceanography, especially multidisciplinary topics, as well as presentations that reflect new and emerging research on the global ocean and society, including science education, outreach, and public policy
In a new study published in Science, NOAA and NASA scientists used space-borne observations of carbon dioxide (CO2) from NASA’s Orbiting Carbon Observatory-2 satellite, or OCO-2, to characterize the tropical atmospheric CO2 response to the strong El Niño event of 2015-2016. The El Niño provided NASA and NOAA an unprecedented opportunity to test the effectiveness of this new observation tool. OCO-2 is NASA’s first satellite designed to measure atmospheric carbon dioxide with the precision, resolution, and coverage necessary to quantify regional carbon sources and sinks.
Observations of carbon dioxide concentrations over the tropical Pacific from the satellite were validated by data from NOAA’s Tropical Pacific Observing System of buoys, which directly measure carbon dioxide concentrations at the surface of the ocean. Both observing systems showed that in the early months of the El Niño, during the spring of 2015, outgassing of carbon dioxide over the tropical Pacific Ocean significantly declined by 26 to 54 percent.“This response is consistent with what we expect from a theoretical understanding, and comparable to what the NOAA data suggests,” said Richard Feely, senior scientist at NOAA’s Pacific Marine Environmental Laboratory, who is a co-author on the paper.
This research is part of a series of studies to better understand the growth of carbon dioxide concentrations in the global atmosphere using the new NASA satellite. The studies show how various regions contribute to those emissions or serve as sinks, absorbing carbon dioxide emissions at different times.
Two Saildrones headed to the tropical Pacific Ocean to enhance the Tropical Pacific Observing System
A saildrone as it passes the Golden Gate Bridge in San Francisco, CA. Photo Credit: Saildrone, Inc.
On September 1, two saildrones launched from the Saildrone Inc. dock in Alameda, CA to begin their six-month, 8,000-nautical-mile, round-trip mission to the equator to improve the Tropical Pacific Observing System (TPOS). These saildrones are a component of a broader effort to rethink the Tropical Pacific Observing System (TPOS) that supports sub-seasonal to seasonal forecasting for the US. TPOS provides real-time data used by the US and partner nations to forecast weather and climate, including El Nino. The mission will be testing if this new, enhanced tool can collect a variety of measurements at a quality that matches research ships and proven mooring technology, Tropical Atmosphere Ocean (TAO) array. If this is the case, they may become a powerful tool to provide key observations for weather forecasts.
The saildrones are headed to the California Current Ecosystem (CCE) for a short test before taking part in a larger field study with NASA at the NASA SPURS study site in the eastern Tropical Pacific. The saildrones will perform an intercomparison with the Woods Hole Oceanographic Institution’s (WHOI) buoy and collect observational date in the study site. The saildrones will also do a calibration exercise with a research ship to ensure the accuracy and quality of the measurements that are being collected. This is particularly important to scientists when testing new sensors and technologies. Then the saildrones will travel south to the equator to do intercomparisons with the TAO moorings before heading back to Alameda, CA.
If the mission is successful, the improved data collection can help improve forecasts for El Nino’s and other weather phenomena that develop in the tropical Pacific and strongly impact North American weather patterns.
Read more about the Saildrone missions in the Arctic and the Tropical Pacific here.