WINDS IN CHINA
The prevailing winds blow across southern China from the southeast. Further north they blow in from the west. The Chinese began using weather cocks and vanes very early and were probably the pioneers of wind direction devices. At least as early as the first century B.C., the Chinese recorded "wind seasons," and used kites to record the speed and direction of the 24 seasonal winds. In some places the first autumn breeze is known as the sz. In other places you can find whispering winds that go I tien tien fung.
Monsoon winds, caused by differences in the heat-absorbing capacity of the continent and the ocean, dominate the climate. Alternating seasonal air-mass movements and accompanying winds are moist in summer and dry in winter. North China and southward are affected by the seasonal cold, dry winds from Siberia and the Mongolia Plateau between September/October and March/April. Summer monsoon winds bring warm and wet currents into South China and northward. There are often vicious storms, heavy rains, floods and landslides in the early summer. Cyclonic storms sometimes approach from Europe. Typhoons strike from time to time, particularly along the southeast coast, in late summer and early fall.
The climate of China is influences very much by the Jet Stream and the prevailing westerly winds. Jet stream winds that blow at high altitudes and blow weather to the east are caused by excessive pressure difference and ribbons of high speed air within the Westerlies. They can blow in excess of 200 miles per hour. As air flows from high pressure and high temperature areas at the equator to low pressure and low temperatures areas at the poles, the earth’s rotation deflects the air in the Northern and Southern hemispheres in a basic east to west direction. This deflection, known as the Coriolis effect, creates west-to-east winds called the Westerlies.
Dust Storms in China
Northern China, including Beijing, and western China are struck with fierce sand storms and dust storms in late winter and early spring. The winds generally blow from west to east and kick up tens of millions of tons of top soil each day. The storms are produced by atmospheric low pressure cells that develop over Mongolia and create windy conditions in the Taklamakan and Gobi deserts. The storms are worse when the climate is hot and dry. In 2003, the storms were less severe than usual. This was attributed mainly to more rain in the Gobi and the failure of atmospheric low pressure cells to develop over Mongolia.
The yellow dust kicked up these storms refers not so much to the color of the dust while it is in the air but more to the film of dust left on cars, windows and other surfaces by the winds. The air and skies are usually a kind of brownish gray. Sometimes the sand mixes with snow and causes yellow snow.
Sand storms reduce visibility to less than one kilometer. The dust and sand in the air damages the lungs and irritates the eyes. Homeowners have to work to keep the dust out of their homes. Fierce sand storms, propelled by powerful winds, in Xinjiang have destroyed houses and cracked double-gazed windows.
The storms become particularly dangerous when they move east and pick up industrial pollutants such as arsenic and dioxins and heavy metals such as copper, cadmium and lead when they pass over China’s heavily industrialized northeast and dumps these pollutants further west, sometimes in Korea and Japan, even the U.S.
Dust Storms and Desertification in China
Storm sand left behind in Beijing Dust and sand levels are exacerbated by drought and desertificaton. Drought robs the soil of moisture, making it easier for the soil to be picked up the wind. Drought in the winter is particularly damaging because it dries the soil before the big winds arrive in late winter and early spring.
In recent years, the dust storms have been occurring earlier, with greater frequency, lasting longer, and carrying stronger winds and more dust. One study found severe storms have increased from five in the 1950s to eight in the 1960s, 13 in the 1970s, 14 in the 1980s and 23 in the 1990s. Storms with unusual ferocity have hit Beijing. Not far from the Beijing villages are being gobbled up by moving sand dunes.
In the 2000s an average of about five or six dust and sand storms a year strike Beijing and the rate was increasing. In 2006, 10 dust struck Beijing. Desertification in western China and Mongolian steppes has made sandstorms worse in recent years. Global warming is blamed for producing milder and dryer winters that loosen the soils which are easily lifted by the spring winds.
Huge sand and dust storms used to occur regularly in the springtime but seem to occur less now. The massive planting of trees and bushes in fragile areas has reduced their occurrence and intensity to some degree, but the expansion of cities and industries and overgrazing by animals has put environmental pressure on the places the storms occur.
Damaging Dust and Sand Storms in China
Dust and sand storms in the Yellow River valley and the Gobi desert are so strong that planes can’t fly and transportation is brought to halt. Yurts get knocked over. People stay indoors and stuff rags under their doors to keep dust and sand from blowing in. People that go outside are forced to wear surgical masks to keep from choking on the yellow dust and sand.
A dust storm in April 2006 dumped an estimated 330,000 tons of yellow sand on Beijing, making parts of the city look like a desert. The storm was especially damaging because the grains of sand from the Gobi Desert were larger than usual and winds were unusually strong. The storm turned the skies of Beijing brownish yellow; left a thick covering of sand on homes, streets and cars; filled hospitals with people with respiratory diseases; and prompted authorities to raise dust and pollution warnings to their highest level and advised people to either wear face masks or stay indoors. The same storm kicked up high winds across the Gobi Desert that created huge dust clouds, toppled houses, buried railroads and roads and killed one person. A train in a remote stretch of desert had it windows broken by sand-laden winds.
Gobi dust in South Korea A sand storm in February 2010 turned the streets of Beijing yellow and raised the air quality level to a rare top-level “5" or “hazardous” rating. Most people stayed indoors. Those that went outside wore face masks and even then said they could taste the dust. Some people left behind footprints where dust had settled in the streets. A warning for the storm issued for a large swath of China went: “We advise friends in these areas to reduce their outdoor activities as much as possible. When you go out, please take measures to protect against the sand such as wearing cotton clothes, masks and glasses to avoid the sand harming your eyes and respiratory system.”
In April 2014, a strong sandstorm swept Gansu Province in northwest China reducing visibility to less than 30 meters, according to the provincial meteorological center. Reuters reported: “The sandstorm, the strongest since 1996 according to reports, started in the early afternoon in Dunhuang County. "Suddenly it became dark and I can't tell whether it's day or night," said one resident. "My nose hurts and I can't open my eyes," another resident said. The Jiuquan City Meteorological Center, which includes Dunhuang, issued a sandstorm red alert, the highest level alert, forecasting that visibility would be reduced to less than 164ft throughout Jiuquan on Wednesday evening. As well as Dunhuang, neighbouring counties were also affected, with Guazhou, Subei, Yumen and Jinta counties also issuing sandstorm red alerts. [Source: Reuters, April 23, 2014]
In March 2021, Beijing and a wide swath of the China’s north were engulfed in the worst sandstorm. Associated Press reported: “Skyscrapers in the center of Beijing appeared to drop from sight amid the dust and sand. Traffic was snarled and more than 400 flights out of the capital's two main airports were canceled before noon. The National Meteorological Center said the sand and dust affect 12 provinces and regions from Xinjiang in the far northwest to Heilongjiang in the northeast and the eastern coastal port city of Tianjin. “This is the most intense sandstorm weather our country has seen in 10 years, as well as it covering the broadest area," the center said in a post on its website. “It wasn't clear if the storm was related to a recent general decline in air quality despite efforts to end Beijing's choking smog. [Source: Associated Press, March 15, 2021]
Global Impact of the Dust Storms in China
Yellow dust from north-central China blows into Korea and Japan and sometimes makes its way across the Pacific to North America. So much of China's topsoil blows away that scientists at the Mauna Loa Observatory in Hawaii can detect the dust within a matter of days after the spring winds starts. One storm in 2001 "blanketed areas from Canada to Arizona with a layer of dust."
Yellow sand from huge springtime storms in northern China often hit Korea and Japan in March or April. The chocking clouds — which are like gritty fast-moving fogs and can be seen as yellow blobs from weather satellites — were particularly bad in 2000, 2001 and especially 2002. After a wicked dust storm hit Seoul in March 2002, schools were closed; clinics were filled with people with respiratory problems; drugs stores ran out of cough medicine and face masks; and nonsmokers felt like smokers.
The yellow sand causes respiratory problems in northern China and South Korea and tinges laundry yellow. During the storms the amount of particulate matter in the air can increase 30 times. One South Korean weather service employee told the New York Times, “There is no way for us to deter this. All we can do is try to forecast the yellow dust storms as early as possible, but with the current technology we can only detect it one day ahead of time at best.
Satellite image of a Gobi dust storm
In Japan, the storms are more of a nuisance than a health hazard. During particularly bad ones, the air is gritty and gray and cars are covered by a yellow film and the percentage of faulty products produced by precision machinery factories increases, but people generally don’t have respiratory problems.
Recent studies have revealed that yellow sand is not entirely a bad thing. It can neutralize acid rain, and has beneficial affect on the marine environment. Yellow sand contain highly-alkaline calcium carbonate, which neutralizes acid and absorbs acid-rain-producing sulfur dioxide. When it falls over the sea it is consumed by plankton which in turn provide food for fish. The sand is also rich in phosphorus and iron which can help fertilize the soil
China withdrew from a scheme to cooperate with Japan and South Korea on observing, forecasting and reducing airborne desert sand, citing weather information as state secrets.
Tornadoes in China
Places in China, including Beijing, occasionally get hit by tornadoes, sometimes accompanied and devastating hail storms. In May 2004, a storm in Hunan Province produced fist-size hail and a tornado that killed seven people The tornado knocked down centuries-old trees, power lines and large advertising billboards and destroyed a number of homes. In June 2004, a hail storm that produce egg-size hail in Handan city on northern China injured 32 people and caused a massive power outage. In July 2005, a tornado struck a town in Lingi Country, killing 15 people. In Anhui Province a tornado struck 33 villages in 2007. In June 2008, a tornado in Anhui Province destroyed 650 homes and killed one person and injured 45, eight seriously. In May 2010, a tornado and strong winds struck Chongqing in southwestern China, killing 25 and injuring 150.
In May 2021, Back-to-back tornadoes killed at least 10 people in central and eastern China and left more than 300 others injured, officials and state media reported. According to Associated Press: “Six people died in the inland city of Wuhan and four others in the town of Shengze, about 400 kilometers (250 miles) east in Jiangsu province. A tornado first struck Shengze about 7 p.m., toppling factory buildings and damaging electricity facilities. The Suzhou city government, which oversees the town, said in a social media post that four people had died and 149 others had minor injuries. Shengze is near Shanghai on China’s east coast. [Source: Associated Press, May 15, 2021]
“A tornado then hit Wuhan about 8:40 p.m. with winds of 86 kilometers (53 miles) per hour, destroying more than two dozen homes and triggering a power outage affecting 26,600 households. The Wuhan government said six people had died and 218 were injured.Xinhua said that 27 homes collapsed in Wuhan, and another 130 were damaged. Construction site sheds and two cranes were also damaged, while downed power lines knocked out electricity, the news agency reported. Photos showed a swarm of rescuers searching through building debris in Wuhan after midnight Friday and workers clearing metallic debris at a factory in Shengze in the morning.
Dust Devil Lifts Elementary Schoolboy Into the Air in Gansu, China
In April 2016, three dust devils tore through an elementary-school sports event in Gansu Province in north-central-western China, lifting one boy into the air and dropping him on the ground, according to local media and video of the event. NBC News reported: “The student suffered minor head injuries and was taken to the hospital following the incident at Yuanquan Primary School, in China's northern Gansu province. [Source: Alexander Smith, NBC News, April 21, 2016]
“Chinese state-run broadcaster CCTV said the first dust devil measured between 100 and 130 feet in height."We immediately started to evacuate the students. But in a very short time, the second round of the dust devil arrived," Fang Fang, a teacher at the school, told the broadcaster. The second twister was larger still, and video footage showed debris being blown into the air as students tried to lie flat in the open area. "We brought the short and thin children together to lie on the ground," Fang told CCTV.
Lightning in China
Lightning killed 499 people in China in 2007, more than double the number during the previous year. All the victims were villagers. Seventy-nine percent were struck while working in fields. Jiangxi Province recorded the highest number of lightning deaths — 166. [Source: CNN]
A sixteen-hour storm in Chongqing in July 2007 that produced 40,000 lightning bolts killed 15 people, left more than 100 injured, caused 10,000 houses to collapse and brought air , train and road traffic to a complete stop. The airports was closed; rail lines were severed; roads were cut off; electricity turned off — cutting off Chongqing from the outside world.
Number of lightning fatalities, injuries and damage reports, and their ranks for all provinces in China from 1997 to 2009.
Province — Fatalities — Rank — Injuries — Rank — Damage Reports — Rank
Guangdong —— 595 —— 1 —— 518 —— 2 —— 17098 —— 1
Jiangxi —— 494 —— 2 —— 293 —— 5 —— —— 2448 —— 8
Yunnan —— 491 —— 3 —— 590 —— 1 —— 1950 —— 9
Guizhou —— 301 —— 4 —— 345 —— 3 —— 937 —— 17
Sichuan —— 261 —— 5 —— 239 —— 8 —— 1596 —— 13
Fujian —— 255 —— 6 —— 175 —— 10 —— 4585 —— 4
Guangxi —— 248 —— 7 —— 273 —— 6 —— 1735 —— 11
Hubei —— 244 —— 8 —— 251 —— 7 —— 1800 —— 10
Jiangsu —— 238 —— 9 —— 104 —— 15 —— 3263 —— 5
Hunan —— 221 —— 10 —— 300 —— 4 —— 4968 —— 2
Shandong —— 219 —— 11 —— 175 —— 11 3188 —— 6
Anhui —— 159 —— 12 —— 140 —— 13 —— 1728 —— 12
Zhejiang —— 158 —— 13 —— 140 —— 14 —— 4815 —— 3
Hainan —— 143 —— 14 —— 199 —— 9 —— 639 —— 19
Henan —— 136 —— 15 —— 152 —— 12 1456 —— 14
Hebei —— 125 —— 16 —— 85 —— 18 —— 3045 —— 7
Liaoning —— 115 —— 17 —— 47 —— 22 —— 1384 —— 15
Inner Mongolia —— 92 —— 18 —— 66 —— 20 482 —— 20
Tibet —— 75 —— 19 —— 90 —— 17 —— 165 190 —— 28
Jilin —— 63 —— 20 —— 36 —— 25 —— 99 758 —— 18
Heilongjiang —— 61 —— 21 —— 44 —— 24 443 —— 21
Shaanxi —— 56 —— 22 —— 66 —— 21 —— 122 —— 22 —— 357 —— 23
Chongqing —— 55 —— 23 —— 95 —— 16 —— 425 —— 22
Qinghai —— 42 —— 24 —— 84 —— 19 —— 244 —— 26
Shanghai —— 36 —— 25 —— 31 —— 26 —— 247 —— 25
Shanxi —— 36 —— 26 —— 16 —— 30 —— 306 —— 24
Gansu —— 33 —— 27 —— 27 —— 27 —— 130 —— 29
Xinjiang —— 33 —— 28 —— 18 —— 29 —— 95 —— 30
Beijing —— 17 —— 29 —— 46 —— 23 —— 1007 —— 16
Tianjin —— 17 —— 30 —— 2 —— 31 —— 236 —— 27
Ningxia —— 14 —— 31 —— 23 —— 28 —— 59 —— 31
Total —— 5033 —— 4670 —— 9703 —— 61614
[Source: “Lightning Casualties and Damages in China from 1997 to 2009, Wenjuan ZHANG, Qing MENG, Ming MA, Yijun ZHANG, Laboratory of Lightning Physics and Protection Engineering, Chinese Academy ofMeteorological Sciences, Beijing, China, 2010 vaisala.com
Forty Killed During Hour-Long Hailstorm in China
snow in Anhui Province in 2008 In May 2012, AFP reported: “Forty people were killed when a brief but violent hailstorm and torrential rain swept through a mountainous region of northwest China. Eighteen others remained missing in Min county, a disaster-prone area of Gansu province, while 87 had been sent to hospital, the local government said. Officials said 29,300 people were evacuated after rain and hail battered the county for just an hour later. It "wreaked havoc" on all of the county's 18 townships and affected more than two-thirds of its 450,000 residents, the state-controlled Xinhua news agency reported. [Source: AFP, May 13, 2012 ***]
"Roads were blocked, houses collapsed, farmland was destroyed, and the power supply and telecommunications services were disrupted by the extreme weather," the agency said, quoting Xu Guangyao, a senior county official. Min county is 90 miles from Zhouqu county, where a rain-triggered mudslide killed about 1,500 people in August 2010.Hailstorms in the central province of Hunan have also killed six people and left one missing, according to statistics released by the Ministry of Civil Affairs, Xinhua reported. Since May 8 hailstorms have struck across the province, affecting 3.42 million people, the ministry said. About 64,000 people have been relocated to safer areas and 7,600 houses have collapsed. ***
In June 2005, walnut-size hail dung a freak storm caused $6 million worth of damage in Beijing. The storm only lasted 10 minutes but the hail broke windows, dented cars and destroyed crops. In May 2006, hail and rainstorms killed 12 people, destroyed 3,234 houses an damaged 155,000 hectares of crops in Shandong Province. Another storm that produced egg-size hailstones, flash floods and high winds killed at least 25 people in Henan Province. The hail storm lasted for 25 minutes in Zhengzhou, Henan’s capital, where buildings collapsed and hospitals were swamped with people who sustained injuries after being struck by hail and debris.
Cold Weather and Snow Storms in China
The Chinese have traditionally worn layers of thick cotton coats in the winter. Cold days and very cold days are often referred respectively to as "two-coat weather" and "three-coat weather."
A cold snap in late 2009 and early 2010 left Beijing blanketed in snow with 12 centimeters of snow reportedly near the Great Wall. Schools were closed, flights were canceled, roads were closed extra buses were ordered and thousands f residents were ordered to help clear icy roads and paths, Vegetable prices rose as greenhouses were affect and the high demand for coal and gas for heating produced shortages,
In January 2010, extreme cold and blizzards in Xinjiang left four people dead and half million snowed, More than 100,000 hoes were allted and more than 15,000 head of cattle were killed.
A blizzard in Sichuan in 1996 left 21 dead, 147 disabled and 10,000 with frostbite. Forty people were killed and 40,000 were injured during deadly snowstorms in Sichuan in the winter of 1997.
An "eye-blinding" snow storm trapped 47 trains and closed a rail line in central China for nine days. Over 100,000 tons of sand was dumped on the tracks in an attempt to clear the snow and 10,000 passengers had to be evacuated.
An intense winter storm in November 2008 killed nine people, stranded 2,150 herders and caused the evacuation of 2,000 others. Linzhi in southeast Tibet was one of the worst hit places. Nearly continuous snow for 36 hours left snow that was an average of 1.5 meters deep.
The winter of 2009-2010 in Beijing was especially cold. Among those who suffered the most following the largest blizzard in fifty years, were residents of art districts that faced forced evictions and the loss of electricity, water, and heat. Heavy early snowstorms in November 2009 in the northern and central provinces of Hebei, Shanxi, Shaanxi, Shandong and Henan killed 40 people, caused thousands of buildings to collapse and destroyed almost 200,000 acres of winter crops. Nineteen of the deaths resulted from traffic accidents. Chinese media reported that some of the snow was induced by cloud seeding. The total damage was estimated to be around $700 million.
Blizzards in Inner Mongolia, see Mongolia.
Ice and Snow Storms in China in 2008
snow in Anhui Province in 2008
In late January and early February 2008, freezing rain and the worst snow storms in 50 years struck central China. More than 300,000 homes collapsed and 1 million more were damaged. One million people were evacuated. Factories suspended operation. Power plants ran out of fuel. Stores ran out food. Transportation was paralyzed. Thousands of flights were canceled. One traffic jam stretched for 70 kilometers. Millions suffered a cold, dark New Year without heat, light or electricity. The biggest snowfalls since 1954 hit Hunan, Hubei, Guizhou, Jiangxi and Anhui Provinces. Some places recorded of the coldest temperatures in over a century.
For two weeks there was near continuous ice and snow storms. Some of the worst weather occurred just as the Chinese New Year holiday was getting underway. Millions were left stranded in train cars and railway stations. Migrant workers were told to scrap plans to return home. For some it was their first chance to go home in years. One of the worst places to be was Guangzhou train station, where about 800,000 people were stranded when the storms were at their peak. Hundreds of thousands were stranded at Guangzhou train station, where crowds were sprawled into the streets around the terminal. The only people who seem to make out were ticket scalpers who were able to command high prices for scarce seats on the train that were going. Things weren’t much better on the roads. One traveler who took 11 days to reach his destination told Reuters, “On the road, we had to move forward step by step, stopping every 100 or 200 meters....yesterday, the whole day we moved only one kilometer.”
At least 130 people were killed. In southern China. Eleven electricians were killed as they reconnected electricity lines and broke ice from power lines. People died in traffic accidents and collapsed buildings., One traveler was killed during a stampede to get on a train. A single traffic accident on a mountain road in road in Guizhou province which caused a bus to plunge 40 meters down a slope was blamed for killing 25 people, 21 of them on the bus. A 14-car pile up in Yunnan killed five people.
The storms lashed areas that are used to relatively warm winter weather. More than 300,000 troops and nearly 1.1. million militia and army reservists were called upon to help get the transportation system going and repair power lines. Tanks were deployed to clear ice from roads. Automatic weapons were used to knock ice off power lines. The fact the military had be dispatched was seen as a sign of poor planning on the part of the government.
Damage from the Ice and Snow Storms in China in 2008
Chenzhou, a city of four million in Hunan, went without power for almost two weeks in early February. Food and gasoline supplies ran dangerously low. People huddled under blankets and gathered around cooking stoves to stay warm. There were serious concerns about social unrest. In mid February heavy snows in Yunnan blocked more than 14,000 kilometers of roads, paralyzed 20,000 vehicles and stranded 180,000 people.
Agriculture in some places was severely disrupted by the storms, Regions hit by the storms supply much of China with its winter fruits and vegetables. By one estimate 59 percent of the crops were lost in affected areas. Some winter crops were completely wiped out. This and the power shortages and factory closures were devastating to the economy in some parts of China, By some estimates the storms cost Chinese economy over $12 billion.
Environmental damage was also severe, About one tenth of China’s forests were damaged. In some areas 90 percent of the forest were ruined, much of it from ice. In Yunnan, a tanker truck carrying more than 30 tons of sulfuric acid crashed on a highway between Anning and Chuxiong spilling much of its contents into a river alongside the highway and causing “serious pollution.”
Lightly -built towers and poles buckled from the weight of the snow while ice snapped transmission lines. It wasn’t until March that power was completely restored. Total losses were estimated at over $21 billion Toyota and Honda closed factories in areas not affected by the storm because of fall out from the storm.
Heavy Snow Storms in China Kill 40
In November 2009, Associated Press reported: “Unusually early snow storms in north-central China have claimed 40 lives, caused thousands of buildings to collapse and destroyed almost 500,000 acres of winter crops, the Civil Affairs Ministry. Nineteen of the deaths resulted from traffic accidents related to the storms that began Nov. 9, the ministry said in a statement on its Web site. [Source: Associated Press , November 13, 2009]
The snowfall is the heaviest in the northern and central provinces of Hebei, Shanxi, Shaanxi, Shandong and Henan since record keeping began after the establishment of the Communist state in 1949, the ministry said without giving detailed figures. It estimated economic losses from the storm at $659 million. Chinese state media say some of the snow was induced through cloud seeding, although the precise amount of snowfall in all areas was not reported and it wasn't clear what the previous records were.
Hebei's provincial capital, Shijiazhuang, received the heaviest snowfall — 3.7 inches — on Nov. 10, the day of the heaviest flurries. Neighboring Beijing, which usually suffers through long, cold and extremely dry winters, reported about 1 inch. More than 7.5 million people have been stranded or otherwise affected by the storms, which caused the collapse of more than 9,000 buildings, damaged 470,000 acres of crops, and forced the evacuation of 158,000 people, the ministry said.
State media have reported at least two deaths were caused by the collapse of buildings, including a school cafeteria. Beijing has been hit by three successive waves of snow, causing havoc on roadways and forcing the cancellation or delay of scores of flights. The capital and surrounding areas are little prepared to deal with such heavy snow, with few plows or road deicing supplies. Snow tires and chains are almost unknown and many drivers simply leave their cars at home and turn to public transport in such conditions.The impact has been far greater in the surrounding provinces of Hebei, Shanxi, Shaanxi, Shandong and Henan, where highways have been closed, schools shuttered, and crews sent to rescue people in their snowbound homes.
Freak snow and ice storms last year hit parts of eastern and southern China unaccustomed to such weather. Those storms paralyzed key transport systems just as millions of migrant workers were heading home for the Lunar New Year holiday, leading to more than 80 deaths and billions of dollars in damage.
Image Sources: 1) Dartmouth College; 2, 3) All Posters com Seach Chinese Art ; 4) NASA; 5) UNCCD; 6, 9) Xinhua; 7) AFP; 8) BBC; 10) The Hindu; 11) Gary Braasch ; snow from Wiki Commons
Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.
Last updated June 2022