WEEK TWELVE: 24-28 April 2017

Item of Interest:

• Higher than normal tide anticipated this coming week along East Coast -- According to the NOAA National Ocean Service's High Tide Bulletin for Spring 2017, above average tides are expected between 27 and 29 April for most of the Atlantic Coast of the US, stretching southward from Maine to the eastern coast of Florida. A new moon occurring on Wednesday, 26 April, coupled with lunar perigee one day later when the Moon is closest to Earth, is responsible for the perigean spring tide with higher than normal high tides. [NOAA National Ocean Service News]
• Worldwide GLOBE at Night 2017 Campaign is underway -- The fourth in the series of GLOBE at Night citizen-science campaigns for 2017 will continue through Thursday, 27 April. GLOBE at Night is a worldwide, hands-on science and education program designed to encourage citizen-scientists worldwide to record the brightness of their night sky by matching the appearance of a constellation (Leo in the Northern Hemisphere and Crux in the Southern Hemisphere) with the seven magnitude/star charts of progressively fainter stars. Activity guides are also available. The GLOBE at night program is intended to raise public awareness of the impact of light pollution. The next series in the 2017 campaign is scheduled for 17-26 May 2017. [GLOBE at Night]
• Planet Earth seen between Saturn's rings -- An image of Earth was recently generated from data collected by a sensor onboard NASA's Cassini spacecraft that is currently passing planet Saturn. This image, obtained in mid April, shows Earth as a point of light appearing between the icy rings of Saturn; a zoomed-in image also shows Earth's moon as a fainter nearby point of light. At the time the image was obtained, the Cassini spacecraft was 870 million miles from Earth. [NASA Jet Propulsion Laboratory News]
• Accessing and interpreting climate data -- If you would like to obtain a variety of climate data for your home town or state that are available from the National Weather Service, please read this week's Supplemental Information...In Greater Depth. This Supplemental not only identifies some of the sites to find the data, but also provides you with a brief explanation of the terminology used to identify the climate data.

Ocean in the News:

• Eye on the tropics -- During the last week tropical cyclones were monitored in the Northern Hemisphere:
  • In the North Indian Ocean basin, Tropical Storm Maarutha traveled toward the northeast over the Bay of Bengal, making landfall along the coast of Myanmar at the start of last week. After making landfall, Maarutha weakened rapidly. Locally heavy rainfall and strong winds accompanied Maarutha as it moved inland. Satellite imagery and additional information on Tropical Storm Maarutha is available on the NASA Hurricane Page
    
  • In the western North Pacific Ocean basin, the remnant low pressure system that had been known as Tropical Depression 2W continued to travel to the northwest at the start of last week, crossing the Philippines and then out across the Luzon Strait. Ultimately, Tropical Depression 2W dissipated to the southeast of Taiwan. The NASA Hurricane Page has a satellite image and additional information on Tropical Depression 2W.
    
  • In the North Atlantic basin, a subtropical depression formed nearly 900 miles to the west-southwest of the Azores at the midpoint of last week. Traveling to the north-northwest and then northwest, this subtropical depression intensified and gained tropical characteristics, becoming Tropical Storm Arlene last Thursday afternoon. At that time, the center of Arlene was located approximately 810 miles to the west of the Azores. The formation of an Atlantic tropical storm in April is rare, as Tropical Storm Ana in 2003 is the only other April tropical storm on record. On Friday, Arlene merged with an extratropical cyclone (midlatitude storm) approximately 1235 miles to the west of the Azores. The NASA Hurricane Page has additional information and satellite imagery on Tropical Storm Arlene.
• The 2016 hurricane season reviewed -- The 2016 hurricane season in the North Atlantic along with the eastern and central North Pacific is reviewed and compared to the more than 150 years of record keeping in the North Atlantic and the 40 years in the eastern North Pacific. [AMS DataStreme Atmosphere]
• Hurricane awareness tour commences to Mexico and the Caribbean -- NOAA and US Air Force Reserve hurricane experts will embark this coming week (24-29 April 2017) on a six-day, five-city tour to Mexico, Honduras, Grand Cayman, Turks and Caicos, and Puerto Rico in a "hurricane hunter" aircraft designed to raise public hurricane awareness in communities in several countries surrounding the Gulf of Mexico. A series of events will be hosted that would include tours aboard the Air Force Hurricane Hunter aircraft. [NOAA Media Release]
• Five ways listed to view marine wildlife responsibly -- In conjunction with Earth Day 2017, NOAA has issued five ways for the public to view marine life safely and responsibly. Remember the request: "Please, no selfies with the seals!" [NOAA News]
• Recognizing toxicity in the marine ecosystem -- A feature article written by an ecologist and senior staff scientist was posted on the NOAA Office of Response & Restoration's blog focusing upon toxicity in marine environments. Topics covered include how to test for toxicity, the complexities of toxicity testing and observations made over time. [NOAA Office of Response & Restoration Blog]
• Public involvement counts in monitoring humpback whales in Hawaii -- The Hawaiian Islands Humpback Whale National Marine Sanctuary has developed a project called "Sanctuary Ocean Count" that encourages both the public and scientists to observe and assist in monitoring humpback whale populations from the Hawaiian shore, culminating in humpback whale population count events on the last Saturday of every January, February, and March. These count events correspond to peak whale season. [NOAA National Marine Sanctuaries News]
• Scientific expedition to study marine ecosystem returns to West Hawai'i -- During the past week the West Hawaiʻi Integrated Ecosystem Assessment (IEA) research team returned to the coastal waters off West Hawai'i Island (or the Kona coast of the Big Island) onboard the NOAA Ship Oscar Elton Sette to study this dynamic ecological area. This expedition is scheduled to run for two weeks. [NOAA Fisheries Pacific Islands Fisheries Science Center]
• Visualizing changes in size distributions of 22 Bering Sea fish species over three decades of climate variability -- NOAA Fisheries Alaska Fisheries Science Center recently completed a study that examines how the populations of 22 groundfish species in the eastern Bering Sea have changed over 34 years in which varying climate conditions have occurred. The data used in this analysis were obtained from summer bottom trawl surveys across the Bering Sea between 1982 and 2015. Environmental data such as ocean temperature were also collected. This study may help provide clues as to how future climate changes could affect fisheries in upcoming years. [NOAA Fisheries Alaska Fisheries Science Center]
• Coral loss along with slow signs of recovery documented in Central Pacific -- A three-month mission was conducted by scientists from NOAA and partner research institutions onboard the NOAA Ship Hi'ialakai, surveying the health of coral reef ecosystems at unpopulated islands in the Pacific Remote Islands Marine National Monument and Marianas Archipelago. They found that at one of the reefs that experienced a significant number of coral deaths during the 2015-16 El Niño event, there was little evidence of local recovery. However, they did observe some signs of re-growth in some large, long-lived individual corals. [NOAA Media Release]
• Where the money went in the Deepwater Horizon oil spill settlements -- Last week was the seventh anniversary of the explosion of the Deepwater Horizon oil rig that resulted in deaths of 11 people, the injury of 17 others and a massive oil spill across the northern Gulf of Mexico, fouling the coasts of the Gulf Coast States from Florida to Texas. A six-year long legal and environmental battle led to a $20.8 billion settlement, which is the largest in the nation's history. NOAA recently posted a feature describing how the moneys obtained in the settlement were allocated. [NOAA News]
• Review of global weather and climate for March 2017 -- Using preliminary data collected from the global network of surface weather stations, scientists at NOAA's National Centers for Environmental Information (NCEI) have determined that the combined global land and ocean surface temperature for March 2017 was the second highest for any March since sufficiently detailed global climate records began in 1880. This global temperature for March 2017 was 1.89 Fahrenheit degrees above the 20th century (1901-2000) average. This global temperature departure for March 2017 fell behind the record March departure set last year (2016) by 0.32 Fahrenheit degrees.
  When considered separately, the average land temperature for March 2017 was the second highest land temperature for any March in the 138-year period of record, falling below the record set in March 2016. Likewise, last month's average temperature over the oceans was the second highest for March, running behind the record departure set one year ago. Interestingly, the March 2017 monthly global combined sea-land temperature departure from the 20th century average for represents the first time that a monthly departure exceeded 1.80 Fahrenheit degrees in the absence of an El Niño episode across the equatorial Pacific.
  The researchers at the National Snow and Ice Data Center noted the areal extent of the Arctic sea ice for March 2017 was the smallest since satellite surveillance began in 1979. In addition, the extent of the Antarctic sea ice was the smallest in the 39-season record. According to data from the Rutgers Global Snow Lab, the Northern Hemisphere snow cover extent for March was the 24th smallest in the 51-year period of record of satellite observations. [NOAA/NCEI State of the Climate] A global map of Selected Significant Climate Anomalies and Events for March 2016 is available from NCEI.
  A summary article describing the global climate for March and the year to date is available. [NOAA News]
• Coastal communities placed at risk by sea floor erosion in coral reef ecosystems -- Researchers with the US Geological Survey (USGS) recently completed the first ecosystem-wide study of changing sea depths at five large coral reef tracts in Florida, the Caribbean and Hawaii, finding the sea floor to be eroding in all five locations. Coral reef degradation has caused sea floor depths to increase as sand and other sea floor materials have erode. Furthermore, the reefs do not appear to be keeping pace with sea level rise. Consequently, coastal communities protected by the reefs are facing increased risks from storms, waves and erosion. [USGS News]
• An All-Hazards Monitor -- This Web portal provides the user information from NOAA's National Weather Service, FAA and FEMA on current environmental events that may pose as hazards such as tropical weather, fire weather, marine weather, severe weather, drought and floods. [NOAA/NWS Daily Briefing]
• Earthweek -- Diary of the Planet [earthweek.com]

Concept of the Week: Climate Feedback Processes

Earth's climate system includes many interacting variables. Some variables are external to the Earth-atmosphere system and some are internal. External variables include solar energy output and Earth-sun geometry (i.e., the Milankovitch cycles). Internal variables include properties of the Earth's surface (e.g., albedo, moisture), the concentration of key atmospheric components (e.g., greenhouse gases, sulfurous aerosols), and cloud cover and thickness.

An important consideration in understanding how Earth's climate system responds to some perturbation is feedback. Feedback is defined as a sequence of interactions among variables in a system that determines how the system responds to some initial perturbation in one or more of the variables. Variables in Earth's climate system may interact in such a way as to either amplify (positive feedback) or lessen (negative feedback) a change in climate. An example of positive feedback is the ice-albedo effect described in Chapter 12 of the DataStreme Ocean textbook. Less ice cover in the Arctic greatly reduces the albedo of the Arctic Ocean causing higher sea surface temperatures and accelerated melting of the multiyear pack ice.

Consider an example of negative feedback. Increasing concentrations of atmospheric carbon dioxide enhances the greenhouse effect causing global warming. Global warming in turn raises sea surface temperatures and increases the rate of evaporation. A more humid atmosphere means more persistent and thicker cloud cover but clouds have both a cooling and warming effect on the lower atmosphere. The relatively high albedo of cloud tops causes cooling whereas absorption and emission of infrared radiation by clouds causes warming by contributing to the greenhouse effect. Satellite measurements and numerical models indicate that cooling would dominate.

In general, negative feedback tends to dominate over positive feedback in Earth's climate system, limiting the magnitude of climate change. The great thermal inertia of the ocean is the principal reason for dampening the planetary temperature response.

Concept of the Week: Questions

1. Feedback in Earth's climate system that amplifies climate change is described as [(positive)(negative)] feedback.
2. In general, [(negative)(positive)] feedback tends to prevail in Earth's climate system.

Historical Events:

• 24 April 1884...USS Thetis, Bear, and Alert sailed from New York to search for Greeley expedition lost in the Arctic. (Naval Historical Center)
• 24 April 1928...The fathometer was patented by Herbert Grove Dorsey (No. 1,667,540). The invention measured underwater depths by using a series of electrical sounds and light signals. (Today in Science History)
• 26 April 1991...200,000 people were killed as a cyclone caused tremendous flooding which devastated the Bay of Bengal region of Bangladesh and India. (National Weather Service files)
  
• 27 April 1521...The Portuguese navigator Ferdinand Magellan was killed by natives during a tribal skirmish on Mactan Island in the Philippines after completing nearly three-quarters of a trip around the world. One of his ships, the Victoria, under the command of the Basque navigator Juan Sebastiýn de Elcano, continued west to arrive at Seville, Spain on 9 September 1522, the first ship to circumnavigate the globe. (The History Channel)
• 28 April 1947...Norwegian anthropologist Thor Heyerdahl and five others set out in a balsa wood craft known as Kon Tiki to prove that Peruvian Indians could have settled in Polynesia. The trip took 101 days.
• 29 April 1770...The British explorer, Captain James Cook, arrived at and named Botany Bay, Australia. (Wikipedia)
• 30 April 1492...Spain gave Christopher Columbus his commission of exploration. (Wikipedia)
• 30 April 1894...An Antarctic iceberg fragment was sighted at a latitude comparable to Rio de Janeiro. Reported by the ship Dochra, this sighting remains the nearest to the equator that an iceberg has been seen. (Today in Science History)
• 30 April 1991...Southeast Bangladesh was devastated by a tropical cyclone with sustained winds of approximately 150 mph during the early morning. A 20-foot storm surge inundated offshore islands south of Chittagong, taking water from the Bay of Bengal inland for miles. This cyclone resulted in up to 200,000 deaths and $1.4 billion damage. (Accord Weather Guide Calendar)

Return to DataStreme Ocean's RealTime Ocean Portal

Prepared by DS Ocean Central Staff and Edward J. Hopkins, Ph.D.,
email hopkins@aos.wisc.edu
© Copyright, 2016, The American Meteorological Society.