9-13 April 2018

ITEMS OF INTEREST

• Tidal Basin cherry blossoms reach full bloom -- The National Park Service recently announced that Thursday, 5 April 2018 was determined to have been the day when 70 percent of the Yoshino cherry blossoms surrounding the Tidal Basin in Washington, DC were fully blooming. The blooms can be best viewed through the first several days of this week, unless the anticipated snow and strong winds over this past weekend cause them to fall early. [Bloom Watch, National Park Service]
  A warm February in the Middle Atlantic States led to a preliminary forecast for a bloom that would have been in mid-March, but an unseasonably cold March and early April delayed the bloom. A portfolio of pictures showing the cherry blossoms at the Tidal Basin on the Wednesday and Thursday was posted. [Washington Post, Capital Weather Gang]
  The graph of the occurrence of the dates of peak cherry blossom occurrence in Washington, DC beginning in 1921 has been updated through this year. This graph is an example of the display of an assemblage of phenological observations taken over a 98-year span.
  The National Cherry Blossom Festival continues through next Sunday, 15 April.
• Celebrating volunteer researchers as Citizen Science Day approaches -- This coming Saturday, 14 April 2018, is Citizen Science Day, an annual event designed to celebrate and promote the various aspects of citizen science that include amazing discoveries, inspiring projects and dedicated volunteers. In recognition of the contributions made by the citizen scientists who help in monitoring the Earth's atmosphere and oceans, NOAA has been highlighting one of the programs that involves citizen scientist participation each day, beginning on 2 April and continuing through 14 April. [NOAA News]
• Worldwide GLOBE at Night 2018 Campaign for April is underway -- The fourth in the series of GLOBE at Night citizen-science campaigns for 2018 will continue through Sunday, 15 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 with the seven magnitude/star charts of progressively fainter stars. These constellations are Leo in the Northern Hemisphere and Crux for the Southern Hemisphere. Activity guides are also available. The GLOBE at night program is intended to raise public awareness of the impact of light pollution. The fifth series in the 2018 campaign is scheduled for 5-14 May 2018. [GLOBE at Night]
• Linking weather and climate -- Read this week's Supplemental Information.. In Greater Depth for a description the distinction between atmospheric conditions that can be considered as weather events, which may last for time spans of up to a week, from those events with longer time spans of a month to three months that can be considered within the ream of climate analysis or forecasting.

CURRENT CLIMATE STATUS

• Atmospheric rivers are soaking California -- A meteorologist with NOAA's Climate Prediction Center posted an Event Tracker blog on the ClimateWatch Magazine describing the soaking that California received this March by atmospheric rivers following the second-driest winter (December 2017 through February 2018) on record for the entire state. These atmospheric rivers, which include the well-known "Pineapple Express," are long plumes of abundant atmospheric water vapor, clouds and precipitation that are carried across the North Pacific Ocean from tropical and subtropical latitudes near Hawaii to the West Coast of North America. Locally heavy rains of more than ten inches fell in three days (20-22 March) near the coastal community of San Luis San Luis Obispo, CA, while 160 inches of snow fell near Squaw Valley in the Sierras in March to produce a seasonal total of 226 inches. [NOAA Climate.gov News]

CURRENT CLIMATE MONITORING

• National maps of last spring freeze are available -- NOAA's National Centers for Environmental Information has posted a national "Day of the Last Spring Freeze" map that is based on a frost-freeze climatology derived from the 1981-2010 U.S. Climate Normals. The map shown was the median date of the last 32-degree Fahrenheit occurrence in spring (meaning a 50% probability of 32 degrees Fahrenheit) from the "Freeze Normals." [NOAA NCEI News]
  The Midwestern Regional Climate Center (MRCC) is hosting a monitoring, assessment, and networking program called the Vegetation Impact Program (VIP) that is studying major impacts upon vegetation driven by weather and climate conditions. VIP has a Frost/Freeze Guidance Project that is intended to improve communication about the state of vegetation and its susceptibility to potentially damaging low air temperatures. A suite of national frost/freeze maps is available that show current season freezes and climatologies of freezes using 32 degrees and 28 degrees Fahrenheit temperature thresholds. For example, under the "32° F Freeze Climatologies" tab in the left column, click on Date of Median Last 32° F Freeze to produce the national map. Another map can be generated to show the latest last 32° F Freeze. These maps can be used as guidance for spring planting. [MRCC Vegetation Impact Program ] (Note: Clicking on a location on any of the frost/freeze national maps will expand the map to focus on a regional view centered upon three or four states. EJH)
• Satellites document the 30-year decline of two glaciers in northwestern Greenland -- Images made from data collected by two of NASA's Landsat satellites in late September 1987 and 30 years later in September 2017 show how Tracy and Heilprin glaciers, two "marine-terminating outlet glaciers," have been rapidly retreating along the coast of Prudhoe Land in northwest Greenland. The image acquired in 1987 was from data obtained by the Thematic Mapper on NASA's Landsat 5, while the more recent image was from the Operational Land Imager (OLI) on Landsat 8. Scientists report that the Tracy glacier retreated by 364 meters per year between 2000 and 2017, while the Heilprin lost 109 meters per year over the same span. The glacial retreat has been attributed to increasing global temperatures over the last several decades. [NASA Earth Observatory]
• "Top 10 list" is "all about ice" -- A web producer at NASA's Jet Propulsion Laboratory has recently produced a web page that features ten selected items concerning various aspects of ice on planet Earth, including its measurement using several new Earth observing satellite platforms and aircraft. NASA is scheduled to launch the GRACE Follow-On (GRACE-FO) mission this year to track the movement of water over the planet, including Earth's frozen regions. The ICESat-2 spacecraft will also be launched this year by NASA that is designed to precisely measure the changing elevation of ice around the world using an onboard laser instrument. Operation IceBridge, NASA's aerial survey of polar ice, is also featured. [NASA Global Climate Change News]

CLIMATE FORCING

• Rocks are found to be a significant source of global nitrogen -- Researchers from the University of California Davis and Terra Analytics in Helena, MT report that up to 26 percent of the nitrogen in natural ecosystems originates from rocks, with the remaining fraction from the atmosphere, which until recently was thought to have been the sole source of nitrogen on Earth. Their discovery could greatly improve climate change projections, which rely on understanding the carbon cycle. Since nitrogen availability is a central controller of terrestrial plant growth, it could also feed the carbon cycle on land, allowing ecosystems to remove more carbon emissions from the atmosphere, thereby influencing global climate change. [University of California Davis News]
• Newest editions of historical natural hazard events posters have been released -- A collaboration between NOAA's National Centers for Environmental Information (NCEI), its World Data Service (WDS) for Geophysics and the International Tsunami Information Center (ITIC), a UNESCO/IOC-NOAA partnership, has resulted in three updated poster-size maps that show the worldwide distribution of major tsunamis, earthquakes and volcanic eruptions over the last several millennia. One of the updated posters is entitled "Tsunami Sources 1610 B.C. to A.D. 2017." Over 1200 confirmed tsunami source events are displayed on the map that are from earthquakes, volcanic eruptions, landslides and other causes. These displayed events are from the 2500 events contained in the NCEI Global Historical Tsunami Database. The second poster, with a title "Significant Earthquakes 2150 B.C. to A.D. 2017," contains the locations of destructive earthquakes around the globe of many of the approximately 6000 earthquakes that are archived in the NCEI Significant Earthquake Database. The third poster has a title of "Significant Volcanic Eruptions 4360 B.C. to A.D. 2017" and displays many of the roughly 800 volcanic eruptions contained in the NCEI Significant Volcanic Eruptions Database. [NOAA NCEI News]

CLIMATE FORECASTS

• Early forecast for 2018 Atlantic hurricane season is made -- Last week, the hurricane forecast team from Colorado State University headed by Dr. Phil Klotzbach released its initial "Extended Range Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2018" that provides projected estimates of the number of named tropical cyclones (hurricanes and tropical storms) during the upcoming hurricane season that officially begins on 1 June 2018. The team, which had been formed by the late Professor William Gray, foresees slightly above-average tropical cyclone activity during this upcoming hurricane season. The team's initial April forecast envisions fourteen named tropical cyclones, which include seven hurricanes. Of these hurricanes, the forecasters foresee three major hurricanes (category 3 or higher on the Saffir-Simpson Scale). A typical North Atlantic hurricane season would have slightly more than ten named systems, based upon long-term averages running from 1931 to 2010. The average number of hurricanes is six per annum. A slightly above-average probability is anticipated for major hurricanes making landfall along the United States coastline and in the Caribbean in 2018. The team bases their outlook on the likelihood that the current weak La Niña conditions will evolve into ENSO-neutral conditions during the next several months. They do not foresee any development of an El Niño event by late summer and early autumn during the peak in the Atlantic hurricane season. However, the waters of the western tropical Atlantic are anomalously warm, while the eastern tropical Atlantic and far North Atlantic are anomalously cool over the past month, which indicates that the Atlantic Multi-Decadal Oscillation index is close to the long-term average. [The Tropical Meteorology Project]
  In mid-May, forecasters with NOAA's Climate Prediction Center (CPC) also should provide their outlook for the 2018 Atlantic hurricane season.

CLIMATE AND THE BIOSPHERE

• Spring appears to be arriving earlier in U.S. National Parks -- Although this spring appears to be lagging across northern sections of the 48 contiguous United States, ecologists with the U.S. National Park Service (NPS) and their colleagues in other agencies and research institutions report that spring is appearing much earlier during the last few years than at the beginning of the 20th century. They based their conclusions on the analysis of two indicators made in 276 NPS units: one of these indicators is the date of appearance of the "first leaf" from buds on vegetation and the other is the date of "first bloom" when blossoms appear. They found that these indicators showed that spring was earlier than in 1901 in more than three-quarters of the park units they studied. For example, the first leaf is occurring three weeks earlier in Washington's Olympic National Park, where first bloom is nearly two weeks earlier. Along the Appalachian Trail, first leaf and first bloom are nearly a week earlier over the 20th century. The earlier springs in the nation's national parks are attributed to a changing climate with higher temperatures. [NASA Earth Observatory]

PALEOCLIMATE RECONSTRUCTION

• Reconstructing past climate records could involve five creative proxy indicators -- For more than a century, paleontologists have been using a variety of proxy indicators that approximate past climate in the absence of direct measures such as temperature using thermometers or precipitation using rain gauges. These proxy indicators include tree rings, corals, cave formations, cores of ocean or lake sediments and ice cores to reconstruct climate records over long time intervals, often extending back a million years into the past. Some of these efforts during the last half century have used radiochemical analysis involving the determination of ratios between heavy and light isotopes of such chemical elements as oxygen, carbon and nitrogen to ascertain if the climate at some time in the past were hot, cold, dry, or wet. Recently, some scientists have employed novel proxy indicators such as bat guano, Roman aqueducts, snail shells, whale earwax and sponges. [EOS Earth & Space Science News]
• Annual growth increments in fish otoliths can serve as proxy indicators of past climates -- Fish otoliths are hard calcium carbonate structures in the vestibular labyrinth of fish that are used for hearing. Annual growth increments (annuli) can form in these fish otoliths, with changes in the width of the annuli indicative of changes in the environment where the fish reside. Therefore, chronologies of temperature can be generated from these otoliths in an analogous fashion to what dendrochronologists extract from their analysis of tree-ring width. Fish otolith chronologies have been reconstructed over a 25-year interval for yellowfin sole in Alaska's Bering Sea. [NOAA Fisheries Alaska]

CLIMATE AND SOCIETY

• More solar than fossil fuel generating power capacity added around globe in 2017 -- According to the recently-released "The Global Trends in Renewable Energy Investment 2018 report," a record 98 gigawatts of new solar capacity were added to the Earth's power generation network in 2017. This new investment in solar generation capacity far exceeded the net additions of any other technology that included renewable, fossil fuel or nuclear. Furthermore, solar power also attracted far more investment, at $160.8 billion (which is up 18 per cent) than any other technology. [United Nations Environment News]
• Carbon intensity of the nation's power sector has dropped to a record low -- The 2018 Carnegie Mellon Power Sector Carbon Index, which was recently released by Mitsubishi Hitachi Power Systems and Carnegie Mellon University, reveals that US power plant emissions averaged 967 pounds (lb) of carbon dioxide (CO₂) per megawatt hour (MWh) in 2017, which was down 3.1 percent from the prior year and down 26.8 percent from the annual value of 1,321 lb CO₂ per MWh in 2005. This Index tracks the environmental performance of US power producers and compares current emissions to more than two decades of historical data collected nationwide. [Carnegie Mellon University College of Engineering News]
• Earthweek -- Diary of the Planet [earthweek.com]

Concept of the Week: Evolution of Climate Models

Climate scientists have been building increasingly sophisticated, mathematical climate models to serve two main purposes: test the sensitivity of the climate to altered conditions and simulate climate over time, either back into the past or forward into the future. The simplest, early type of climate model (zero dimensional) was the "energy balance model", which provides an average planetary temperature from incoming and outgoing radiation. A one-dimensional energy balance model determines the surface temperature from the energy balance at individual latitude belts.

More complex models involve the physical equations of motion (gas laws, thermodynamics and radiation interactions) subject to climate forcings, the boundary conditions of solar radiation, surface properties and atmospheric composition. As computers improved, models have included a three-dimensional oceanic circulation ("atmosphere-ocean coupling"), then interactions between the atmosphere, cryosphere and geosphere, with climate feedback mechanisms involving the exchanges of heat and water. Finally, models have been able to incorporate the improved knowledge of the biogeochemical processes. Climate models calculate variables such as temperature at individual points within the three-dimensional grid of cells across the Earth's surface and vertically through the atmosphere, ocean, ice and land. A tradeoff exists between the number of grid points (the spatial resolution) and the number of numerical computations. Time and space accuracy costs increased computational time and expense.

The development of numerical weather prediction models during the 1960s and 1970s spurred the development of General Circulation Models (GCMs) for climate. One of the early atmospheric GCMs was developed at Princeton University's Geophysical Fluid Dynamics Laboratory (GFDL). By the 1990s, comprehensive climate models were being perfected with three-dimensional oceanic circulation. Ultimately, the term GCM could be used to refer to a Global Climate Model that represents the major climate system components (atmosphere, ocean, land surface and polar ice) and their interactions. The Community Climate Model at the National Center for Atmospheric Research is one of the most comprehensive climate models currently available. This model has been used to determine the future temperature response for several scenarios concerning the release of greenhouse gases through the 21st century as proposed by the IPCC reports.

Historical Events:

• 9 April 1983...Hottest day in Malaysian historical record, as the temperature reached at Chuping, Malaysia reached 101 degrees, a record that was tied nine days later. (The Weather Doctor)
• 9 April 2000...A record April snowfall of 14.6 in. shut down Montreal, Quebec. Snow removal contracts had ended on 1 April. (The Weather Doctor)
• 9 April 1995...Glasgow, MT recorded 12.2 inches of snow in 24 hours, its greatest 24-hour snowfall on record. (Intellicast)
• 10 April 1985...A late season cold snap in the east set record low April temperatures in the following cities: Asheville, NC, 23 degrees; Beckley, WV, 11 degrees; Elkins, WV, 3 degrees. April record lows were tied in Raleigh-Durham, NC (23 degrees) and Roanoke, VA (20 degrees). (Intellicast)
• 10 April 1996...A wind gust of 253 mph was measured when the eyewall of Tropical Cyclone Olivia passed over Australia's Barrow Island. This gust became the highest surface wind speed record, replacing the 231-mph wind gust measured at New Hampshire's Mount Washington Observatory on 12 April 1934. (Accord Weather Guide Calendar)
• 12 April 1815...Massive eruption of Mount Tambora in Indonesia blew 400 cubic kilometers (100 cubic miles) of ash skyward. Eruption disrupted the global weather for several years, particularly noteworthy: the cold summer of 1816 in North America and Europe. (The Weather Doctor)
• 12 April 1934...Winds atop Mount Washington, NH (elevation 6288 feet) averaged a world record 186 mph for five minutes, with a peak gust from the southeast of 231 mph, which is the highest wind speed ever clocked in the world. (David Ludlum) On 10 April 1996, a wind gust of 253 mph was measured when the eyewall of Tropical Cyclone Olivia passed over Australia's Barrow Island and is now considered to be the highest surface wind speed record. (Accord Weather Guide Calendar)
• 12 April 1985...Key West, FL set a new record for April rainfall in a 24-hour period as 6.06 inches of rain were recorded, eclipsing the previous record of 6.04 inches which fell on 29 April 1941. In addition, the heavy rainfall shattered the old record for this date set back in 1931 when 1.49 inches of rain fell. (Intellicast)
• 12 April 1996...Duluth, MN recorded 1.7 inches of snow on this day to raise its seasonal snowfall total to 132.8 inches -- its snowiest winter on record. The old record was 131.6 inches set back in 1949-50. (Intellicast)
• 13 April 1955...The town of Axis, AL was deluged with 20.33 inches of rain in 24 hours establishing a state record. (The Weather Channel)
• 13 April 1985...The high temperature of 86 degrees for this date at Medford, OR was the highest ever so early in the spring season. (Intellicast)
• 14 April 1933...The state intensity record for snowfall for New Hampshire was set at Franklin Lake as 35 inches fell in 24 hours. (Intellicast)
• 14 April 1986...The world's heaviest hailstone, weighing 2.25 pounds, fell in the Gopalganj District of Bangladesh. This hailstone could have reached speeds in excess of 90 mph. The hailstorm killed 92 people. (Accord's Weather Guide Calendar) (Wikipedia) (National Weather Service files)
• 15 April 1921...Two-mile high Silver Lake (elevation 10,220 ft) in Boulder County, Colorado received 75.8 in. of snow in 24 hrs, the largest 24-hr total of record for North America. The storm left a total of 87 in. in twenty-seven and a half hours. (David Ludlum)
• 15 April 1927...New Orleans, LA was drenched with 14.01 inches of rain, which established a 24-hour rainfall record for the state. This record was eclipsed in August 1962, when 22.00 inches fell in a 24-hour span. (The Weather Channel)

Return to RealTime Climate Portal

Prepared by Edward J. Hopkins, Ph.D., email hopkins@aos.wisc.edu
© Copyright, 2018, The American Meteorological Society.