WEEKLY CLIMATE NEWS

WEEKLY CLIMATE NEWS

WEEK TWELVE: 24-28 April 2017

ITEMS OF INTEREST

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]
Celebrating National Arbor Day -- This coming Friday, 28 April 2017, many locations across the nation will celebrate Arbor Day, a day when the planting of trees is encouraged. Arbor Day was originally proposed in 1872 by J. Sterling Morton, Nebraska's first newspaper editor, and continues to be most often celebrated by individual states on the last Friday in April. However, since planting conditions vary greatly due to the state's climate it may occur from September to May. In Arkansas, Arbor Day is celebrated on the third Monday in March, but in Alaska, the date is the third Monday in May. For your state's observance (and name of the official state tree), please consult the National Arbor Day Foundation.
National Science Bowl set for next weekend -- The US Department of Energy (DOE) National Science Bowl®, a nationwide academic competition for middle and high school students will be held through next weekend (27 April -1 May 2017) in Washington, DC. This event will test students' knowledge in all areas of science and is meant to encourage high school students to excel in science and math and to pursue careers in those fields. [DOE Office of Science]
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]
State, national and global instrumental records -- Temperature and precipitation data have been collected around the world since the mid-19th century. Beginning in the 1890s, a sufficiently dense climate network has been established in the United States and its territories. The records from around the nation and from around the global have been collected and archived at several central locations, such as NOAA's National Climatic Data Center (NCDC). Scientists at NCDC along with colleagues at NASA's Goddard Institute for Space Studies and in the United Kingdom have produced time series of area-average monthly and annual temperatures for over a century on state, national and global space scales. For more details on these records and how to access them, please read this week's Supplemental Information...In Greater Depth.

CURRENT CLIMATE STATUS

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]
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]
California's Sierra snowpack in 2017 is larger than last four snow seasons combined -- Data recently collected by NASA's Airborne Snow Observatory (ASO) show that the snowpack in California's Tuolumne River Basin in the Sierra Nevada is currently greater than that of the four previous years combined. This finding is good news as the snowpack in this basin represents a major source of water for San Francisco and California's Central Valley. [NASA Earth Observatory]
Monitoring the replenishment of California reservoirs from space -- Three sets of images obtained from the Operational Land Imager (OLI) on NASA's Landsat 8 satellite show how this the heavy precipitation that fell this past winter across California has replenished the surface water supply in some of the Golden State's reservoirs following a five year drought. Satellite images were made of three reservoirs (Trinity Lake, Don Pedro Reservoir and Castaic Lake) in 2015 when water levels were exceedingly low and during the last two months after the reservoirs had refilled following a sequence of atmospheric river events that brought abundant moisture from the tropical and subtropical Pacific. [NASA Earth Observatory]

CLIMATE FORECASTS

New Seasonal Climate Outlooks released -- During the last week, forecasters at NOAA's Climate Prediction Center (CPC) released their Three-Month (Seasonal) Climate Outlooks for the three-months running from May through July 2017, which contains the last month of meteorological spring and the first two months of two months of meteorological summer. Specific details of their outlooks include:

Temperature and precipitation outlooks -- According to their temperature outlook, essentially all of the 48 contiguous United States should experience a high chance of above average temperatures for these three upcoming months, with the greatest probability of such an occurrence being found along the Atlantic Seaboard, the Gulf Coast and sections of the Southwest. Only sections of the northern Rockies and northern Plains were expected to have nearly equal chances of warmer or cooler than normal conditions.
Their precipitation outlook calls for better than even chances of dry conditions for May through July 2017 across the northern and western Great Lakes States with the highest chances of dry weather centered on northern Wisconsin and Michigan's Upper Peninsula. Conversely, many states across along the Rockies and the western Gulf Coast were expected to have a better than even chance of having above median precipitation. These regions extend from Montana southward to New Mexico and from the lower Texas Gulf Coast eastward to the Mississippi Delta in Louisiana. The rest of the contiguous United States should have equal chances of below and above median precipitation for late spring and early summer. [NOAA Climate Prediction Center] Outlooks for May are also available. A summary of the prognostic discussion of the outlook for non-technical users is available from CPC. These forecasts were based in part upon the anticipated continuation of ENSO-neutral conditions through late meteorological spring and into early summer 2017 in the Northern Hemisphere. However, atmospheric conditions appear to contain a residual component of the weak La Niña event that ended earlier this year.
Seasonal Drought Outlook released -- The forecasters at CPC also released their US Seasonal Drought Outlook that would run from mid April through July 2017 in which drought conditions were expected to persist or expand across the Southeast, extending from the Tennessee Valley in Mississippi and Alabama eastward across Georgia and South Carolina. Some of this region is currently under moderate to extreme drought conditions. The region in the Southwest currently under moderate drought should also expected to see continued drought conditions into midsummer. This region is primarily along the US-Mexican border in Arizona and California and in the region around Los Angeles.. Improvement in drought conditions was expected across the scattered areas in the central and northern Plains, along with sections of the Florida Peninsula, the Middle Atlantic States and southern New England. Most of these areas could be removed from drought consideration. Note: a Seasonal Drought Outlook Discussion is included describing the forecasters' confidence.

CLIMATE AND THE BIOSPHERE

Trace gas found to be a key to estimating how plant growth surges with increases in carbon dioxide -- Scientists have found that a trace atmospheric gas, carbonyl sulfide (COS), can be used to estimate how plant growth increases along with rising levels of atmospheric carbon dioxide. An international team of scientists from the US, France and Finland have reviewed the 54,000-year record for atmospheric carbonyl sulfide from measurements of air trapped in the snowpack at the South Pole. They found that as emissions of carbon dioxide from burning fossil fuels increased since the start of the 20th century, plants around the world are utilizing 30 percent more carbon dioxide, spurring plant growth. [NOAA News]
Climate-related planting zone maps reveal effects of changing climate --In recognition of Earth Day, a member of NOAA's Climate Program Office wrote a feature for ClimateWatch Magazine investigating how changing climate conditions across the nation could have an effect upon when a garden should be planted in spring. She focuses upon maps of Plant Hardiness Zones and how they have changed over the last five decades. Plant Hardiness Zones are based upon the average lowest winter (minimum) temperatures across the nation for 1981-2010 that are then put into 10-Fahrenheit degree bins. Interactive planting zone maps show how these zones have changed over time, as comparison has been made with the Plant Hardiness Zones computed for 1971-2000. These maps represent a collaboration between NOAA's National Center for Environmental Information and the American Public Garden Association. [NOAA Climate.gov News]
Life-detecting devices being tested in one of the Earth's driest climate --A team of researchers from NASA and several research universities tested devices that are meant to detect life on distant planets last February on Chile's Atacama Desert, arguably called the world's driest climate. One of the devices was a portable chemistry lab called the Chemical Laptop developed at NASA's Jet Propulsion Laboratory that checks liquid samples for a set of 17 amino acids from which the presence of life may be inferred. The Atacama Desert was selected as it has little precipitation, which would provide water needed for life. Some weather stations on the Atacama Desert of northern Chile and southern Peru have never reported measurable precipitation, while others have received as much as 0.6 inches of rain per year on average. [NASA Jet Propulsion Laboratory 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]
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]

CLIMATE AND SOCIETY

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

Concept of the Week: Climate Sensitivity

Climate sensitivity is a relatively new and powerful concept in climate science. It is a measure of how responsive the temperature of Earth's climate system is to a change in radiative forcing due to increases in atmospheric carbon dioxide, an important greenhouse gas, combined with the contributions of feedbacks within the system. Specifically, the term is defined as how much the global mean surface temperature will increase if there is a doubling of atmospheric greenhouse gases (in terms of equivalent CO₂), once the planet has had a chance to settle into a new equilibrium after the increase occurs. In other words, it's an assessment of how Earth's climate will respond to that doubling.

According to NASA climate scientist James Hansen, the concept of climate sensitivity has its origins in a request made by President Jimmy Carter in 1979 for the National Academy of Sciences (NAS) to report on the potential impact on climate of the increasing atmospheric concentration of carbon dioxide. Jule G. Charney (1917-1981) of the Massachusetts Institute of Technology (MIT) led the Academy investigation team. He designed a now classic experiment where computer models of Earth's climate system had the atmospheric concentration of CO₂ doubled while all other variables (except temperature) were held constant.

The addition of CO₂ makes the atmosphere more opaque for outgoing infrared radiation (heat), warming the lower atmosphere and cooling the upper atmosphere. Applying basic radiation laws, Charney found that doubling the atmospheric CO₂ concentration would reduce the net radiative flux (from Earth to space) at the tropopause by a global average of about 4 watts per square meter (W/m²). How much warmer would Earth's surface become as a consequence of this enhanced greenhouse effect? According to the Stefan-Boltzmann law, the radiation emitted by an object is directly proportional to the fourth power of the object's absolute temperature. To reestablish radiative equilibrium following a doubling of atmospheric CO₂, Earth must radiate to space an additional 4 W/m², brought about by a global warming of 1.2 Celsius degrees (or 0.3 Celsius degrees per W/m²).

Charney's initial experiment accounted for the effect of a forcing agent (i.e., atmospheric CO₂) on global climate but not the influence of feedbacks. As noted in the Concept of the Week for Week 2, forcing agents and mechanisms drive climate change, while feedbacks determine the magnitude of climate change. Hence, Charney's "no-feedback" experiment significantly underestimates the amount of global warming likely to accompany a doubling of atmospheric CO₂. With inclusion of feedbacks, the 1979 Academy study indicated that global warming could range from 2 to 3.5 Celsius degrees. The most recent IPCC report (AR4) estimates the magnitude of warming with feedbacks incorporated as 3 Celsius degrees with a range of uncertainty of 2 to 4.5 Celsius degrees. This greater sensitivity depends primarily on all the different feedbacks, both positive and negative, that either amplify or diminish the greenhouse effect. The three primary feedbacks involve clouds, sea ice, and water vapor.

In summary, climate sensitivity is usually expressed in terms of the equilibrium change in global mean annual surface temperature caused by an increment in downward infrared radiative flux that would result from sustained doubling of atmospheric CO₂ concentration compared to its pre-industrial level (taken to be 280 ppmv).

Concept of the Week: Questions

All other factors being equal, the addition of CO₂ to the atmosphere [(increases) (decreases)(has no effect upon)] the flux of infrared radiation from Earth's surface to space.
Charney's initial estimate of the amount of global warming that would accompany a doubling of atmospheric CO₂ [(did)(did not)] account for the temperature change(s) likely to accompany feedbacks in Earth's climate system.

Historical Events:

24 April 2003...The temperature at Juneau, AK soared to a maximum of 70 degrees, the earliest occurrence of a 70-degree reading for the period of record in Alaska's capital city. (The Weather Doctor)
25 April 1875...New York City received three inches of snow, the latest measurable snow of record for that location. (David Ludlum)
25 April 1898...The temperature at Volcano Springs, CA hit 118 degrees to establish an U.S. record for the month of April. (The Weather Channel)
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 1915...The temperature at Washington, DC hit 92 degrees, the highest ever in April. New York City hit 92 degrees as well. (Intellicast)
27 April 1931...The temperature at Pahala, located on the main island of Hawaii, soared to 100 degrees to establish a state high temperature record. (The Weather Channel)
27 April 1960...The highest temperature ever recorded in Thailand reached 112 degrees at Uttaradit, Thailand . (The Weather Doctor)
27 April 1988...Mount Washington, NH reported seven ft of snow in ten days, pushing their snowfall total for the month to 89.9 in., surpassing the previous record of 89.3 in. set in 1975. Records have been kept at the Observatory on the summit since December 1932. (The National Weather Summary) (Intellicast)
27 April 2003...The largest hail storm ever recorded at Key West, FL was reported between 4:10 and 4:20 PM, hailstones ranging in size from one-half inch up to one and three-quarter inches fell. It is the eleventh recorded hail event (since 1871) at Key West. (The Weather Doctor)
28 April 1973...The all-time record crest of the Mississippi River at St. Louis, MO was recorded at 43.3 ft, exceeding the former 1884 mark by 1.9 ft. (Intellicast) This record has since been exceeded by a record flood level of 49.6 feet on 1 August 1993. (National Weather Service)
29 April 1910...The temperature at Kansas City, MO soared to 95 degrees to establish a record for the month of April. Four days earlier the afternoon high in Kansas City was 44 degrees, following a record cold morning low of 34 degrees. (The Weather Channel) (The Kansas City Weather Almanac)
North America's deadliest rockslide was caused by snowmelt followed by temperatures near zero degrees Fahrenheit that caused water in the rock joints under Turtle Mountain in the Canadian Rockies to freeze and expand. Ninety million tons of limestone fell some 3000 ft onto Frank, AB. As many as 70 people died as the result of the rockslide. (Accord's Weather Guide Calendar)
29 April 1912...The highest temperature ever recorded in Oceania was 108 degrees that occurred on this date at Tuguegarao, Philippines. (The Weather Doctor)
29 April 1973...The Mississippi River reached a crest of 43.4 ft at St. Louis, MO, breaking the previous record of 42 ft established in 1785. (David Ludlum)
30 April 1888...World's deadliest hailstorm occurred at Moradabad, India as enormous hailstones killed 230 persons and many livestock. An additional 16 people died in another town. (The Weather Doctor)
30 April 1991...Memphis, TN set a new monthly rainfall record for April with 17.13 inches of rain. The old record was 13.90 inches set back in 1877. (Intellicast)
30 April 1994...The rain finally stopped on the Kaneohe Ranch on the Hawaiian island of Oahu, ending a streak of 247 consecutive days of rain that began 27 August 1993. (The Weather Doctor)
30 April 2011...There were 758 tornadoes in the U.S. in April 2011, the most ever recorded in a month (beating the old record by 216). (National Weather Service files)

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