WEEKLY CLIMATE NEWS

12-16 March 2018

This is Break Week for the Spring 2018 offering of this course. This Weekly Climate News contains new information items and historical data, but the Concept of the Week (below) is repeated from last week.

ITEMS OF INTEREST

Worldwide GLOBE at Night 2018 Campaign for March is underway -- The third in the series of GLOBE at Night citizen-science campaigns for 2018 will continue through Saturday, 17 March. 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 for latitudes equatorward of 30 degrees latitude in the Northern Hemisphere and Canis Major for all latitudes in 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 fourth series in the 2018 campaign is scheduled for 6-15 April 2018. [GLOBE at Night]
Cherry Blossom Watch in Washington, DC -- Many tourists descend upon Washington, DC during the spring to view the sights, including the blossoming cherry trees that line the Tidal Basin along the Potomac River. This year marks the 90th anniversary of the first Cherry Blossom Festival. The National Park Service operates a website that reports the status of the cherry blossoms in anticipation of the timing of peak bloom. According to their most recent forecast, experts expect that the trees should be at peak bloom between 17-20 March 2018. The 2018 National Cherry Blossom Festival will start on Tuesday, 20 March, and run through Sunday, 15 April 2018. The current dates of anticipated bloom are earlier than the average peak bloom date of 2 April. This website also has a listing of the phenological observations for past bloom dates over the past 26 years.
A four-minute video "Climate Change and Cherry Blossoms in Washington, DC" is available on the National Park Service website and describes how the earlier blossoming of cherry trees indicate a changing climate.
A graph of the occurrence of the dates of peak cherry blossom occurrence in Washington, DC beginning in 1921 and running through last year is also available. Examination of this graph indicates that the anticipated peak bloom could rival the record earliest occurrence on 15 March 1990.
Update on Iditarod Trail Sled Dog Race -- After the ceremonial start of the Iditarod Trail Sled Dog Race in Anchorage one week ago Saturday, the official start of the race was in Willow last Sunday. As of early Sunday some of the mushers had left the Kaltag checkpoint, headed for Unalakleet. The winner of the Iditarod race is expected to reach Nome early this week.[Fairbanks Daily News-Miner]
A website is maintained for teachers and students interested in following the progress of the Iditarod and a 5th-grade teacher from Virginia, who is the "2018 Iditarod Teacher on the Trail™." Current weather conditions and weather forecasts for this year's checkpoint stations are available.
Viewing atmospheric circulation in three-dimensions -- Read this week's Supplemental Information.. In Greater Depth for information concerning the average circulation in the lower and upper troposphere.

CURRENT CLIMATE MONITORING

Extent of Arctic sea ice during this February is smallest since 1979 -- A map of the sea ice concentration in the Arctic basin during this past February shows that the extent of sea ice was the smallest since satellite surveillance commenced in 1979. A “winter warming event” appears to be responsible for the decline in ice over the Bering and Chukchi Seas. A map displaying the February air temperature anomaly (arithmetic differences between observed and long-term average monthly temperatures) shows positive anomalies associated with above average temperatures across a large section of the Arctic basin. [NASA Earth Observatory]
Satellite-based solar telescope provides new view of the Sun -- The Solar Ultraviolet Imager (SUVI) that is onboard NOAA’s GOES-16 satellite has been providing images of the Sun’s atmosphere in the extreme ultraviolet region of the electromagnetic spectrum since the satellite was launched into a geosynchronous orbit in November 2016. NOAA’s National Centers for Environmental Information (NCEI) and the Cooperative Institute for Research in Environmental Sciences (CIRES) are releasing images of the Sun made from the SUVI to the scientific community. The recently launched GOES-S satellite is also carrying a SUVI sensor. [NOAA NCEI News]
Following the advance of spring with phenological maps -- The USA-National Phenology Network (NPN)is producing a variety of maps of the 48 contiguous United States that show the advance of spring northward across the nation. Two “Status of Spring” maps, called the “Spring Leaf Index Anomaly” and the “Spring Bloom Index Anomaly” are generated on a weekly basis based upon the USA-NPN’s model called the Spring Leaf and Bloom Indices. The timing of leaf-out, migration, flowering and other seasonal phenomena in many species are phenological events that are closely tied to local weather conditions and broad climatic patterns. These maps are anomaly charts showing how the calculated indices for each week compare with the corresponding 30-year averages (for 1981-2010) and provide a means of comparison of this spring with “normal” conditions. [USA-National Phenology Network Spring]
USA-NPN is also generating some pilot Pheno Forecast maps that are based on their 6-day Accumulated Growing Degree Day (AGDD) forecasts. These Pest-detection, management, and treatment Maps are available for five pests: apple maggot, emerald ash borer, hemlock woolly adelgid, lilac borer and winter moth. The treatment window for these pests are displayed as it approaches, based on predicted life stage. [USA-NPN Pheno Forecasts]

CLIMATE FORCING

Carbon can be unleashed from far northern permafrost within decades -- Scientists from NASA's Jet Propulsion Laboratory, the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, the National Center for Atmospheric Research (NCAR) and the University of Alaska Fairbanks recently determined that permafrost in the coldest northern Arctic will thaw sufficiently to become a permanent source of carbon to the atmosphere during the 21st century, with the peak transition occurring in 40 to 60 years. On the other hand, warmer, more southerly permafrost regions are not expected to become a significant carbon source until the end of the 22nd century, warmer, more southerly permafrost regions will not become a carbon source until the end of the 22nd century, even though they are presently thawing. The researchers based their conclusions on data on soil temperatures in Alaska and Siberia and output from a numerical model from NCAR that calculates changes in carbon emissions as plants grow and permafrost thaws in response to climate change. [NASA Jet Propulsion Laboratory Feature]
An update on gas hydrates is made from a modern perspective -- The U.S. Geological Survey (USGS) recently published two new fact sheets on methane hydrates and related USGS research activities. Methane hydrates are crystalline solids that look like ice and are formed from water and gas, often containing large quantities of the greenhouse gas methane. These gas hydrates are found hidden in sediments on every continent including in Arctic permafrost and in marine sediments directly below the sea floor. One of the USGS fact sheets contains up-to-date information about naturally occurring gas hydrates, including their global distribution, the amount of gas trapped in these deposits, and the technology used to find them. The other fact sheet describes the USGS Gas Hydrates Project, a collaborative effort with other U.S. federal agencies, international partners, and academic researchers to enhance understanding of the resource potential of gas hydrates and the interaction of gas hydrates with the changing environment. [USGS News]

CLIMATE FORECASTS

Updated El Niño/Southern Oscillation (ENSO) Diagnostic Discussion is released -- Late last week forecasters at NOAA's Climate Prediction Center (CPC) and the International Research Institute for Climate and Society (IRI) released their monthly El Niño/Southern Oscillation (ENSO) Diagnostic Discussion. They reported that the La Niña was weakening during February, although sea surface temperatures (SST) across the eastern equatorial Pacific Ocean remained below average. Furthermore, atmospheric conditions typical of La Niña were also weakening. Most of the prediction models used by the forecasters indicate that La Niña should continue weakening and transition into ENSO-neutral conditions (with neither El Niño nor La Niña conditions) during this meteorological spring season in the Northern Hemisphere (March, April and May). The forecasters have continued their La Niña advisory, noting an approximately 55 percent chance that a transition from La Niña to ENSO-neutral conditions would occur during this Northern Hemisphere meteorological spring, then continuing into the second half of 2018. [NOAA Climate Prediction Center]
An ENSO blog was written by a contractor with NOAA's CPC describing how the La Niña conditions that prevailed at the end of 2017 and during the first month of 2018 appear to show a transition into ENSO-neutral conditions across the equatorial Pacific. She provides several informative graphics to supplement her discussion. [NOAA Climate.gov News]
Forecasters with the Australian Bureau of Meteorology reported that La Niña conditions were waning as warming was occurring in the central equatorial Pacific. They suggest that the current phase of the Madden-Julian Oscillation (MJO) could hasten the demise of La Niña and a transition to ENSO-neutral conditions. [Australian Government Bureau of Meteorology]
An El Niño forecast from Down Under -- Forecasters with the Australian Bureau of Meteorology recent reported that several ENSO (El Niño-Southern Oscillation) indicators suggest that the current ENSO-neutral conditions could develop into an El Niño event in the equatorial Pacific Ocean during this calendar year of 2017. The Bureau's ENSO Outlook status has been upgraded to an El Niño WATCH, meaning the likelihood of El Niño forming in 2017 is approximately 50%. [Australian Government Bureau of Meteorology]

CLIMATE AND THE BIOSPHERE

Tree mortality would increase on a warming planet -- An international team of scientists recently reported that several factors are contributing to an increase in the mortality rate of trees in the moist tropics, with trees in some regions dying at double the rates 35 years ago. The researchers studied the tree health in tropical areas of South America, Africa and Southeast Asia, as well as analyzing several factors affecting these trees such as rising temperatures and carbon dioxide levels, droughts, fires, more potent storms and insect infestation. Apparently, increased air temperatures reduces the ability of trees to absorb carbon dioxide for photosynthesis and intensify their loss of water. [Pacific Northwest National Laboratory News]
Ocean waters off West Coast returning to average conditions, but salmon catches are lagging - NOAA's Southwest Fisheries Science Center and Northwest Fisheries Science recently presented their annual "California Current Ecosystem Status Report" that indicates ocean conditions off most of the U.S. West Coast are returning to near average, after an extreme marine heat wave from 2014 to 2016 disrupted the California Current Ecosystem and shifted many species beyond their traditional range. However, the central and southern sections of the West Coast face low snow pack and potential drought in 2018 that could put salmon at continued risk as they migrate back up rivers to spawn. [NOAA Fisheries West Coast Region News]

PALEOCLIMATE RECONSTRUCTION

A "wet lab" experiment is used to model prehistoric ocean conditions -- A laboratory experiment was conducted by an international team of scientists involving a modified graduated cylinder that was used to model Earth's prehistoric ocean with conditions like that of the Archean Era, approximately 2.5 billion years ago. Cyanobacteria were included since these organisms are assumed to have helped fix oxygen into the early atmosphere. The researchers were evaluating the reduction of iron in prehistoric oceans in conditions under which iron-rich sedimentary rock was formed. They found that despite the oxygenation by the cyanobacteria, much of the iron did not remain oxidized but was reduced again into its dissolved form, yielding a larger amount than anticipated. [Iowa State University News]

CLIMATE AND SOCIETY

Earthweek -- Diary of the Planet [earthweek.com]

This Concept of the Week is repeated from last week.

Concept of the Week: Tropospheric westerly winds, north and south

The theoretical existence of upper tropospheric jet stream winds was not confirmed until being encountered by World War II bomber pilots when heading west into strong headwinds at altitudes of approximately 30,000 feet (10,000 m). Wind speeds sometimes exceeded 170 mph causing their relatively slow, heavily laden aircraft to almost stand still. Subsequently, westerly jet stream winds were found to encircle the planet in midlatitudes of both hemispheres above regions of strong temperature contrasts.

The explanation for these winds involves atmospheric mass distributions and forces on a rotating planet. Air in tropical latitudes is warmed, rises and then flows poleward, both north and south. On a rotating planet, moving air is deflected by the Coriolis effect, to the right in the Northern Hemisphere (and left in the Southern). The greater the temperature differences between warm lower and cold higher latitudes, the stronger the air motions and the faster the jet streams. The vertical temperature patterns result in the highest wind speeds near the top of the troposphere.

So Northern Hemisphere air headed northward, deflected to the right ends up headed east, a "westerly wind." In the Southern Hemisphere, southward moving air, deflected left will also go east, as a westerly wind. These "rivers" of strong upper-level winds steer surface weather systems as they move generally eastward across midlatitudes. They also provide boosts for jet aircraft headed eastward with them, but need to be avoided for going west! Of course, the full story is complex as land (especially mountains) and water surfaces interact with the heating of the air and eddies form in the turbulent flows, so jet streams wander. And with them go the storms and the weather patterns that form our short-term climate.

Historical Events:

12-13 March 1907...A storm produced a record 5.22 inches of rain in 24 hours at Cincinnati, OH. (The Weather Channel)
12 March 1923...The record low air pressure of 971.9 millibars (28.70 inches) for Chicago, IL was set during a storm that produced heavy snow, a thick glaze, gales, and much rain that caused $800,000 damage. (Intellicast)
13-15 March 1952...The world's 5-day rainfall record was set when a tropical cyclone produced 151.73 inches of rain at Cilos, Reunion Island in the Indian Ocean. The 73.62 inches that fell in a 24-hour period (15^th-16^th) set the world's 24-hour rainfall record. (Accord's Weather Guide Calendar)
13 March 1993...The "Great Blizzard of '93" clobbered the eastern US and produced perhaps the largest swath of heavy snow ever recorded. Heavy snow was driven to the Gulf Coast with 3 inches falling at Mobile, AL and up to 5 inches reported in the Florida Panhandle, the greatest single snowfall in the state's history. Thirteen inches blanketed Birmingham, AL to set not only a new 24-hour snowfall record for any month, but also set a record for maximum snow depth, maximum snow for a single storm, and maximum snow for a single month. Tremendous snowfall amounts occurred in the Appalachians. Mount Leconte in Tennessee recorded an incredible 60 inches. Mount Mitchell in North Carolina was not far behind with 50 inches. Practically every official weather station in West Virginia set a new 24-hour record snowfall. Farther to the north, Pittsburgh, PA measured 25 inches, Albany, NY checked in with 27 inches, and Syracuse, NY was buried under 43 inches. The major population corridor from Washington, DC to Boston, MA was not spared this time as all the big cities got about a foot of snow before a changeover to rain. A rather large amount of thunderstorm activity accompanied the heavy snow. Winds to hurricane force in gusts were widespread. Boston recorded a gust to 81 mph, the highest wind gust at that location since hurricane Edna in 1954. Numerous cities in the south and mid Atlantic states recorded their lowest barometric pressure ever as the storm bottomed out at 960 millibars (28.35 inches of mercury) over Chesapeake Bay. Some 208 people were killed by the storm and total damage was estimated at $6 billion-- the costliest extratropical storm in history. (Intellicast)
14 March 1944...A single storm brought a record 21.6 inches of snow to Salt Lake City UT. (The Weather Channel)
14 March 1984...A coastal storm dumped very heavy snow over northern New England. Caribou, ME received 28.6 inches of snow in 24 hours, by far its greatest 24-hour snowfall on record. (Intellicast)
15 March 1892...A winter storm in southwestern and central Tennessee produced 26 inches of snow at Riddleton, and 18.5 inches at Memphis, resulting in the deepest snow of record for those areas. (David Ludlum)
15 March 1906...The temperature at Snake River, WY dipped to 50 degrees below zero, a record for the U.S. for the month of March. (Sandra and TI Richard Sanders -1987)
15 March 1952...Over 72 (73.62) inches of rain fell on Cilaos, Reunion Island in the western Indian Ocean, the greatest global 24-hour total rainfall. (The Weather Doctor)
15 March 2004...Rain at Brownsville, TX broke a century-old precipitation record for the greatest daily rainfall accumulation for March with 3.23 inches . (The Weather Doctor)
16 March 1975...A single storm brought 119 inches of snow to Crater Lake OR establishing a state record. (The Weather Channel)
16-17 March 2002...A snowstorm dumped 28.7 inches of snow on Anchorage, AK breaking the old daily record of 15.6 inches. Snow amounts ranged from 24 to 29 inches at lower elevations. (The Weather Doctor)
17 March 1906...The temperature at Snake River, WY dipped to 50 degrees below zero, a record for the coterminous U.S. for the month of March. (Sandra and TI Richard Sanders -1987)
17 March 1998...Calgary, Alberta experienced its worst March snowstorm in 113 years, measuring 13 inches of snow at the airport and from 15 to 18 inches in other parts of the city. (The Weather Doctor)
17-24 March 1999...Intense Tropical Cyclone Vance (Category 5) moved across portions of Western Australia. A record wind gust for the Australian mainland of 167 mph was recorded at the Learmonth Meteorological Office. (The Weather Doctor)
18 March 1914...San Francisco, CA reached its highest temperature ever recorded in March. The mercury rose to 86 degrees. (Intellicast)
18 March 1925...The great "Tri-State Tornado" occurred, the most deadly tornado in U.S. history. The tornado, which claimed 695 lives (including 234 at Murphysboro, IL and 148 at West Frankfort, IL), cut a swath of destruction 219 miles long and as much as a mile wide from east central Missouri to southern Indiana between 1 PM and 4 PM. (David Ludlum) (Intellicast)
18 March 2002...A snowstorm over coastal British Columbia produced the latest and heaviest single-day snowfall on record for the city of Vancouver of 2.55 inches. (The Weather Doctor)

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