Scientists published a study this week in Nature Climate Change revealing future climate change in the tropics will be accelerated by warming in the nearby subtopics.

In response to future fossil fuel burning, climate computer models simulate a pronounced warming in the tropical oceans. This warming can influence the El Niño phenomenon and shift weather and rainfall patterns across the globe. Despite being robustly simulated in computer models of the climate system, the origin of this accelerated tropical warming has remained a mystery. The international research team, led by Malte Stuecker, new assistant professor of oceanography in the University of Hawai‘i at Mānoa School of Ocean and Earth Science and Technology (SOEST), concluded that climate change outside the tropics is the main culprit.

Earth’s future warming will not be identical everywhere. Atmospheric and oceanic circulation changes, as well as cloud processes, will determine which regions will warm faster and which ones will experience a delayed warming relative to the global mean. Focusing on the tropical regions, a team of scientists developed a new method that separates the contributions from local and remote physical processes that cause warming in a given region.

The team found that the expected future warming in the tropics (15^oS-15^oN) originates mostly from warming that occurs in subtropical regions (16^oN-32^oN and 16^oS-32^oS).

“To understand this surprising phenomenon, one has to understand how different areas interact with each other climatically,” said Stuecker, who was at the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea while conducting the study.

A large-scale atmospheric circulation feature referred to as the Hadley cell and its surface branch, known as trade wind circulation, transport relatively dry subtropical air to the tropics. Due to the effects of earth’s rotation, trade winds also cause upwelling of cold subsurface waters in the tropical Pacific and Atlantic.

“In response to increasing greenhouse gas emissions, future subtropical warming will slow down the atmospheric Hadley cell,” adds Stuecker.

This will lead to a weakening of the surface trade winds, less upwelling of cold ocean water, and a resulting warming of the sea surface. In addition, a weaker Hadley cell also means that less humid air is rising, and cloud coverage is reduced in most of the tropics, increasing the amount of sunlight reaching the surface.

“This can further exacerbate future warming in the tropics”, says Axel Timmermann, director of the ICCP and co-author of the study. 

To arrive at these conclusions, the authors used a computer model of the global climate system and ran it for present-day and future CO₂ conditions. By imposing the extra energy related to the CO₂ change, either in the tropics or subtropics, the team then found that human-induced subtropical warming causes about 40% more future tropical surface ocean temperature change than if the same amount of extra energy would enter Earthʻs atmosphere directly in the tropics.

The study presents a new paradigm to understand the patterns of future global warming and the arising regional differences.

“Warming in one area can affect the degree of warming in another place. We are starting to appreciate how strongly different areas are connected in the climate system” said Fei-Fei Jin, co-author and atmospheric sciences professor at UH Mānoa SOEST.

Content courtesy of Kyungmi Park, IBS Center for Climate Physics, Pusan National University.

Read also on UH News and Hawaii News Now.

A team at the University of Hawaiʻi at Mānoa has been awarded a $900,000 grant by the U.S. Department of Agriculture (USDA)’s Natural Resources Conservation Service through a program that supports the conservation of private lands through funding projects centered on technology and innovation.

UH’s project, Forecasting daily reference evapotranspiration and rainfall for water resources conservation and sustainable agriculture, is led by principal investigators Sayed Bateni of the College of Engineering and the Water Resources Research Center (WRRC), Jonathan Deenik and Jensen Uyeda of the College of Tropical Agriculture and Human Resources and Aly El-Kadi of the School of Ocean and Earth Science and Technology and WRRC.

The team aims to demonstrate how farmers can conserve water and be more effective in utilizing water resources by implementing an innovative new method to model and forecast daily rainfall and evaporation in irrigation areas. The approach centers on use of an artificial neural network that breaks down complex long-term time-series into simpler units, providing more accurate forecasting.

The USDA’s Conservation Innovation Grants program awarded a total of $12.5 million in 2019 to 19 different projects addressing areas including water quantity, urban agriculture, pollinator habitat and accelerating the pace and scale of conservation adoption. The goal of the program is to foster innovation to provide solutions to the most pressing issues facing farmers today, using science to support agricultural conservation and sustainability.

Startling data fresh off an eight-year tiger shark study in French Polynesia shows severe impacts the creatures of the sea face long after they are cut loose from fishing lines.

Many sharks are swimming around with stainless steel hooks lodged into their jaws. New research, co-authored by Hawai‘i Institute of Marine Biology associate professor Carl Meyer, revealed sharks can retain those hooks for at least seven years and possibly an entire lifetime.

Watch the video from UH News

“That can have profound consequences for those animals. It can injure or even perhaps kill them because they’re unable to feed properly after these interactions,” said Meyer. The notable shark expert is one of four researchers assigned to the project that launched in 2011.

According to the study, many tiger sharks are accidentally hooked by long line fisheries targeting tuna and swordfish. Data confirmed fishing boats hook millions of sharks each year, and about one-third bite through the line or are set free with hooks protruding from their jaws. Some sharks had up to seven deeply wedged hooks, according to researchers.

Meyer’s four-member team studied 55 tiger sharks just outside Tahiti’s northwest coast. And it was common for sharks to have more than one hook present.

Meyer’s team published their findings in Fisheries Research and are hopeful the study’s data will result in a mandatory overhaul of fishing gear.

“If fisheries were to switch from using stainless hooks to carbon steel hooks then the impact on the sharks would be reduced simply because those hooks would fall out much more quickly,” Meyer explained.

Researchers found sharks shed carbon steel, or corrodible hooks, within two-and-a half years. Stainless steel hooks are no longer permitted for use by longline fisheries in Australia and various entities in the US.

According to the study, hook retention is a widespread issue that likely affects millions of shark species, including blue sharks, silky sharks, oceanic whitetip sharks, mako sharks and thresher sharks. Meyer says it torments tiger sharks in Hawaiian waters, as well. Within a few weeks at the end of 2019, he managed to remove four hooks from sharks off Oʻahu.

The study is geared toward heightening insights into shark conservation and management issues. The World Conservation Union designates tiger sharks as “near threatened” which means they are at risk of becoming endangered.

Read more on UH News, KHON2, and Honolulu Star-Advertiser.

SOEST planetary scientist David Trang co-authored a study published this week in Science Advances that shows lava flows on Venus may be only a few years old, suggesting that Venus could be volcanically active today — making it the only planet in our solar system, other than Earth, with recent eruptions.

“If Venus is indeed active today, it would make a great place to visit to better understand the interiors of planets,” said Justin Filiberto, the study’s lead author and Universities Space Research Association (USRA) staff scientist at the Lunar and Planetary Institute. “For example, we could study how planets cool and why the Earth and Venus have active volcanism, but Mars does not. Future missions should be able to see these flows and changes in the surface and provide concrete evidence of its activity.”

Radar imaging from NASA’s Magellan spacecraft in the early 1990s revealed Venus, our neighboring planet, to be a world of volcanoes and extensive lava flows. In the 2000s, the European Space Agency’s Venus Express orbiter shed new light on volcanism on Venus by measuring the amount of infrared light emitted from part of Venus’ surface during its nighttime. These new data allowed scientists to identify fresh versus altered lava flows on the surface of Venus. However, until recently, the ages of lava eruptions and volcanoes on Venus were not well known because the alteration rate of fresh lava was not well constrained.

Trang, a researcher in SOEST’s Hawaii Institute of Geophysics and Planetology, Filiberto and co-authors recreated Venus’ hot caustic atmosphere in the laboratory to investigate how the observed Venusian minerals react and change over time. Their experimental results showed that once erupted onto the surface, an abundant mineral in basalt — olivine —reacts rapidly with the atmosphere and within weeks becomes coated with the iron oxide minerals magnetite and hematite. Trang’s efforts included relating laboratory results to the results from spacecraft data. They further found that the Venus Express observations of this change in mineralogy would only take a few years to occur. Thus, the new results by Filiberto and coauthors suggest that these lava flows on Venus are very young, which implies that Venus does indeed have active volcanoes.

“It has been decades since the last space mission to explore the surface of Venus and hopefully our findings will persuade the community that we need to go back to further investigate our dynamic neighbor,” said Trang.

Content courtesy of USRA-Lunar and Planetary Institute

Read more in New York Times, Gizmodo, Smithsonian Magazine, KHON2, Hawaii News Now and Big Island Now.

Earth scientists from the University of Hawai‘i at Mānoa recently co-authored a study in Science Advances that investigated the characteristic surface motion that occurs in the weeks to months to years after very large earthquakes. By combining GPS measurements with a new numerical modeling method, the team, led by Jonathan Weiss, postdoctoral researcher and lecturer at the University of Potsdam Institute for Geosciences and alumni of the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), probed the Earth’s structure beneath a portion of the southern Andes.

Weiss, SOEST researcher James Foster and graduate student Jonathan Avery, and international colleagues use a network consisting of hundreds of permanent Global Positioning System (GPS) stations installed across South America—from the Chilean coastline in the west to the rainforests of Brazil in the east—to measure horizontal and vertical ground motions as small as a few millimeters per year. The instruments are similar to but much more precise than those in mobile phones or automobile satellite navigation systems. Studying these motions can reveal detailed information about numerous processes ranging from the forces responsible for mountain building over long timescales, the short-term behavior of rocks in response to large, earthquake-induced changes in stress, and even seasonal cycles of rainfall in the Amazon basin.

The team analyzed continuously recorded GPS data from after the 2010 magnitude 8.8 Maule earthquake in Chile, which was the largest event to occur in that region for 50 years, using a novel geophysical data inversion technique. Their modeling approach used surface motion measurements from GPS data to reveal details of the physical properties of the rock in the crust and mantle, and how it responded to the stresses generated by the earthquake. This innovative and computationally efficient approach contrasts the commonly used forward modeling methods that require immense computational time and resources.

The newly published results of their study confirm that the combination of a dense network of GPS sites with the new inversion algorithm can significantly increase our knowledge of subduction zone and deep crustal and upper mantle structure, which ultimately controls the distribution and frequency of large earthquakes and volcanic activity. Their study provides a new piece of the puzzle that may aid scientists in determining when and where the next destructive earthquake will occur.

Content courtesy of Simon Schneider from University of Potsdam.

A reception was held on the University of Hawai‘i (UH) research vessel Ka’imikai-O-Kanaloa (“Heavenly Searcher of the Seas of Kanaloa”) just before she was sold this fall. Affectionately known to many as the K-O-K, the ship joined the fleet of UH marine expeditionary research vessels on January 15, 1994. Since then, the K-O-K has been used across the Pacific Ocean on a variety of missions that included submersible operations, deployment of deep-sea moorings, hydrographic surveys, and studies of marine biology, chemistry and climate change.

The original vessel was built by Mangrove Shipbuilding Co., Houston, Texas in 1979 and was used for more than a decade for oil and gas exploration. Starting in 1992, UH oceanographer and director of the Hawai‘i Undersea Research Laboratory (HURL), Alex Malahoff, worked tirelessly to acquire and reconfigure this 185-foot offshore supply vessel to serve as the support ship for HURL’s two human-occupied submersibles, Makali’i and Pisces V, the remotely-operated vehicle RC V-150 and, after Makali’i was retired, Pisces IV.

Attendees at the reception included Mrs. Beverly Malahoff, who christened the reconfigured platform, R/V Ka’imikai-O-Kanaloa when she emerged from Bender Shipbuilding and Repair Co. as a versatile 223-foot oceanographic research vessel with a cruising speed of 10 knots, a 15,000 nautical mile range, 50-day endurance, and space for 14 crew members and 19 scientists. The approximately $5 million conversion was funded by the State of Hawai‘i and NOAA, with the State of Hawaii holding the ship’s title.

K-O-K facilitated research in Hawaiian waters and across the Pacific Ocean by scientists from UH and around the world. Some of the K-O-K’s greatest accomplishments using the HURL submersibles include finding the sunken Japanese midget sub that led the December 7, 1941 attack on Pearl Harbor, investigating the chain of active volcanoes running north from New Zealand, long-term monitoring of the changes and growth of Lo‘ihi seamount off Hawai‘i Island and finding dozens of new species in the Papahānaumokuākea Marine National Monument.

“In addition to enabling important discoveries and ocean monitoring efforts, the local access of the KOK made available UH’s UNOLS/AGOR vessels (previously R/V Moana Wave and now R/V Kilo Moana) for extended circum-Pacific expeditions,” said Brian Taylor, Dean of the UH Mānoa School of Ocean and Earth Science and Technology.

One of the most consistent users of the K-O-K was the Hawai‘i Ocean Time-series (HOT) program.  During the period July 1999 through July 2018, 93 separate HOT cruises to the open-ocean Station ALOHA were conducted aboard the K-O-K. The vessel was also used in Hawai‘i for numerous expeditions by the UH Center for Microbial Oceanography: Research and Education (C-MORE) and the UH Simons Collaboration on Ocean Processes and Ecology (SCOPE), including the Life Aquatic in the Volcanic Aftermath (LAVA) expedition in July 2018 to explore the effects of the Kilauea eruption on the marine environment.

After 25 years of scientific voyages for UH, the KOK was retired following her final expedition in July 2018 on the 304^th cruise of the HOT program. In December, the K-O-K was towed to Mexico by an ocean tug where she will be recycled and repurposed.