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Despite rapid Arctic warming, plan for more frigid spells
New research on the Arctic confirms that even as the Arctic is warming faster than the rest of the world, cold-air outbreaks from the polar region will continue across the Northern Hemisphere in the coming decades.
The big challenge now is to better understand what triggers these cold-air outbreak events and how to improve their predictability.
Much of the previous research has shown how a weakening of the stratospheric polar vortex can allow pockets of frigid air to plunge much farther south than normal. The new study, conducted by an international team including Arctic researchers from NOAA, provides additional insights as to how other influences - stalled weather systems, stretching of the stratospheric polar vortex and even events in the distant midlatitudes can influence these polar patterns.
"A better understanding of these Arctic-midlatitude linkages would improve forecasts covering periods of weeks to months, which would give communities more time to plan for adverse winter weather conditions," said co-author Muyin Wang, a scientist from the Cooperative Institute for Climate, Ocean, and Ecosystem Studies who works at NOAA’s Pacific Marine Environmental Laboratory (PMEL). "The impacts can be more significant as societies conditioned to global warming become increasingly less used to them."
The study was published in Environmental Research: Climate.
The stratospheric polar vortex is a mass of cold whirling air bounded by the jet stream that forms 10 to 30 miles above the Arctic surface in response to the large north-south temperature difference that develops during winter. Generally, the stronger the winds, the more the air inside is isolated from lower latitudes, and the colder it gets. But sometimes it can be shifted or stretched off the pole toward the United States, Europe or Asia.
"It seems really counterintuitive, but there will be plenty of ice, snow, and frigid air in the Arctic winter for decades to come, and that cold can be displaced southward into heavily populated regions by Arctic heat waves," said co-author Jennifer Francis with the Woodwell Climate Research Center.
The study, which resulted from an international workshop held in 2023 in Great Britain, provides a new analysis of recent research that offers a pathway to improved forecasts.
The authors said the stratospheric polar vortex has been relatively under-studied in previous reviews of Arctic-midlatitude climate linkages that focus predominantly on the role of changes in the tropospheric polar jet stream. They suggest that future research should focus on the complicated interactions between Arctic, midlatitude and tropical influences.
While many analyses focus on warm Arctic and cold midlatitude events, connections have also been found between unusually cold Arctic temperatures and warm winter events in midlatitudes, especially in Europe.
"Such a range of results confounds those who would like the science to offer a simple way to anticipate seasonal outlooks," said James Overland, a research oceanographer at PMEL.
One of the complicating factors occurs when a weather system stalls, creating an atmospheric block: a quasi-stationary modification of the jet-stream flow that occurs at middle and high latitudes and typically last for one to a few weeks. Blocking events are associated with persistent weather conditions in the vicinity of the block and frequently lead to extreme weather events in midlatitudes, including winter cold air outbreaks.
Tropical climatic drivers, such as the El Niño-Southern Oscillation and the Madden-Julian Oscillation, can create the conditions that lead to the establishment of these atmospheric blocks thousands of miles away.
The study authors underscored the need for research to better understand how to predict cold outbreaks in lower latitudes, which will help communities adapt to the consequences of extreme cold weather.
"The Arctic may seem irrelevant and far away to most folks, but our findings show that the profound changes there affect billions of people around the Northern Hemisphere," said lead author Edward Hanna with the University of Lincoln.
The international research team was composed of scientists from the United States, United Kingdom, Germany, Finland, South Korea, China and Japan.
"The most interesting part of the research is that the polar vortex stretching events could be an important driver of North American cold air outbreaks,” said Amy Butler, a climate researcher with the Chemical Sciences Laboratory who was not involved in the study. “It’s a novel way of looking at how the stratosphere might influence the surface climate - It’s certainly worth understanding better to improve predictability."
(Material from University of Lincoln and Woodwell Institute press releases were included in this story.)
Hanna, E., J. Francis, M. Wang, J.E. Overland, J. Cohen, D. Luo, T. Vihma, Q. Fu, R.J. Hall, R. Jaiser, S.-J. Kim, R. Köhler, L. Luu, X. Shen, I. Erner, J. Ukita, Y. Yao, K. Ye, H. Choi, and N. Skific (2024): Influence of high-latitude blocking and the northern stratospheric polar vortex on cold-air outbreaks under Arctic amplification of global warming. Environ. Res. Clim., 3(4), 042004, doi: 10.1088/2752-5295/ad93f3
Fifty years ago, NOAA created a new environmental research laboratory in Seattle with an initial focus on water quality in Puget Sound, and environmental studies of the Gulf of Alaska and Bering Sea. Since then, the Pacific Marine Environmental Laboratory has evolved into one of the world’s leading ocean research institutes, specializing in observing ocean conditions from tsunamis to changes in climate and ocean chemistry with the aid of innovative instrumentation and measurement strategies often developed by the lab.
To recognize PMEL’s half-century of accomplishments, the journal Oceanography has published a special issue with 29 diverse articles which highlight the laboratory’s scientific work over the last five decades. The issue provides new perspectives on global and regional implications of ocean acidification and its biological impacts, the influence of El Nino-Southern Oscillation on global weather patterns, and the important role marine aerosols play in regulating climate.
“PMEL researchers and their collaborators not only have fundamentally reshaped the scientific understanding of so many aspects of our ocean, their research and explorations have sparked our imagination and fascination with the deep and all that we might learn about our planet,” said NOAA Administrator and former President of The Oceanography Society Rick Spinrad, Ph.D. “Year after year, PMEL scientists continue to inspire the next generation of scientists and researchers, while providing the nation with the priceless knowledge gained by their investigations.”
Discoveries made by PMEL scientists, supported by national and international research partners, have been at the forefront of a sea of knowledge about climate change and variability, extreme weather events, the effects of climate change on marine ecosystems, fisheries oceanography, global patterns and processes of heat and carbon budgets within the oceans, Arctic oceanography, and ocean-seafloor interactive processes such like hydrothermal vents.
“We cannot understand climate change and its impacts on the world without understanding the ocean,” said PMEL director Michelle McClure. “PMEL’s scientists have been leaders in researching our marine system, and we are dedicated to providing the information we need to help society address the climate crisis in the coming decades.”
Special journal issue offers a deep dive into PMEL’s accomplishments
The Oceanography special issue covers the full range of topics that PMEL has studied over its 50 years, from the Arctic to zooplankton.
One study, led by PMEL Senior Scientist Richard Feely, provides a new assessment of rapid changes driven by ocean acidification in regions that would normally be considered refuges, threatening the protection that these regions provide for stocks of sensitive species.
A second, led by PMEL Supervisory Oceanographer Simone Alin, evaluates the sensitivity of Dungeness crab to anticipated ocean acidification trends in near-shore waters of Washington State through 2100. Their modeling studies suggest large declines in landings of crab, which for decades has been the most valuable fishery on the US West Coast, may be seen as soon as 2060 to 2070 under a high-emissions scenario.
An analysis of data collected by the Global Tropical Moored Buoy Array, led by Senior Scientist Michael McPhaden, discusses unusual developments in the El Nino-Southern Oscillation cycle over the past decade, capped off with a rare three-year or “triple dip” La Nina during 2020 – 2023. This recent period of extended cold in the tropical Pacific has upended theories of what causes multi-year La Niñas, while highlighting potential influences from the tropical Indian and Atlantic Oceans as well as from higher latitudes of the Pacific on the predictability of El Nino-Southern Oscillation events.
Decades of measurements by PMEL have revealed the important role of sulfur compounds generated by plankton, sea-spray aerosol and aerosols transported long distances in generating clouds in the marine boundary layer. As detailed in a paper led by PMEL’s lead atmospheric chemist Patricia Quinn, these measurements have been aggregated into the largest global ocean database characterizing a complex mixture of chemical components that are important for climate models to accurately model Earth’s radiation budget.
Fifty years of discovery in ocean science
Since 1974, PMEL engineers and technicians working with scientists in the lab and at sea developed a stream of new technologies needed to expand observational capabilities over vast expanses of ocean. These tools have profoundly shaped scientists’ understanding of Earth system processes, leading to advances in environmental prediction and climate assessments.
Together, this has resulted in more than 3,400 papers published by PMEL scientists over the last 50 years, work that has garnered more than 225,000 citations in peer-reviewed journals. Observational data collected by the lab are used in innumerable oceanographic studies.
“One only has to look at PMEL’s outstanding publication and citation record to know that this is a world-class organization,” said Chris Sabine, who rose from oceanographer to PMEL director during a 15-year stint with the lab. “But as anyone who has been to sea on a PMEL cruise knows, the level of professionalism and preparedness of the seagoing scientists and engineers is unsurpassed,” said Sabine, who is now an Oceanography professor at the University of Hawaiʻi at Mānoa.
“PMEL is an amazing team that includes scientists, support staff, engineers and technicians at all stages of their careers,” McClure added. “The collaboration and cooperation between them all has been a critical component of our past successes – successes that we are committed to continuing as we address the acute challenges of climate and environmental changes.”
Learn more about some of PMEL’s current research, on YouTube or on the website: https://www.pmel.noaa.gov/
Originally posted on NOAA Research on November 1, 2023 View the interactive Oceanography flipbook online: https://oceanographydigital.tos.org/flip-book/110286/579668/page/1
The three Saildrone, Inc. uncrewed surface vehicles were launched from Hawai‘i and currently are at the equator in the central Pacific observing the developing El Niño. Sea Surface Temperature (SST) warmer than 90°F is shown in dark red. SST cooler than 70°F is shown in dark blue. This image was generated within the Saildrone, Inc. mission portal using the SST analysis from the HYCOM ocean prediction system. Click to enlarge map.
The 120-day Tropical Pacific Observing System (TPOS) 2023 Saildrone Mission officially began on June 22, 2023, just after the official start of what experts suggest may be a strong El Niño. The three Saildrone, Inc. Explorer-class Uncrewed Surface Vehicles (USVs), launched from Honolulu, Hawai‘i, are now at the equator in the central Pacific (~155°W), about 1,300 miles south of the Hawaiian Islands. An El Niño state occurs when above-average equatorial sea surface temperatures are present throughout the central and eastern tropical Pacific, leading to a weakening or even reversal of the trade winds near the equator and anomalous weather patterns across the world.
Each USV is outfitted with a suite of sensors to monitor wind stress, air-sea exchanges of heat and carbon dioxide, and surface seawater temperature, salinity, and biogeochemistry. In addition, two of the drones will profile ocean currents to about 100 m depth, while the third will profile the distribution of organisms on a range of trophic levels down to 1,000 m depth.
Overall, this sixth TPOS mission uses Saildrone, Inc. USV for: (a) observing the air-sea interactions, including potential equatorial upwelling, associated with the evolving El Niño system, (b) observing the relaxation of carbon dioxide outgassing from the Tropical Pacific often associated with El Niño events, and (c) supplementing ship-based acoustic fish surveys to assess the distribution of organisms in the water column.
This TPOS mission marks a new collaboration between the NOAA Pacific Marine Environmental Laboratory TPOS team and Dr. Réka Domokos of NOAA Pacific Islands Fisheries Science Center. The Science Center produces science to support the conservation and management of the fisheries and many marine resources in the Pacific Islands Region. “The addition of the acoustic echosounder will allow us to explore the value and feasibility of using long-range USVs to assess the effects of the physical environment on biomass and distribution of organisms within the remote Pacific Islands Regions during a collaborative effort,” said Dr. Domokos. Ultimately, the goal for this new collaboration is to better connect the life cycle with the energy, water, and carbon cycles, thereby improving ecosystem forecasts within Earth system models.
This 120-day mission is supported by NOAA Uncrewed Systems Operations Center and NOAA Uncrewed Systems Research Transition Office. The TPOS mission brings together academic, industry, and international partners with NOAA partners from Research, the Weather Service, Marine and Aviation Operations, and now Fisheries line offices. It highlights NOAA’s efforts to increase innovative applications of uncrewed systems technologies through purchasing data using public-private partnerships and collaboration with academia.
To follow the progress of our mission, visit our blog: https://www.pmel.noaa.gov/ocs/ocs-saildrone-mission-blog-tpos-2023-mission
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.
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.
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.
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.
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