Table 1 List of the observatories used throughout this study
Observatory | Code | λ | ϕ | Period | Observatory | Code | λ | ϕ | Period |
|---|---|---|---|---|---|---|---|---|---|
Abinger | ABN | 51.2 | 359.6 | 1925-1965 | La Quiaca | LQA | -22.1 | 294.4 | 1963-1981 |
Abisko | ABK | 68.4 | 18.8 | 1950-2010 | Lanzhou | LZH | 36.1 | 103.9 | 1980-2006 |
Addis Ababa | AAE | 9.0 | 38.8 | 1959-1995 | Las Mesas | TEN | 28.5 | 343.7 | 1961-1992 |
Agincourt | AGN | 43.8 | 280.7 | 1931-1970 | Learmonth | LRM | -22.2 | 114.1 | 1990-2010 |
Alert | ALE | 82.5 | 297.6 | 1962-2005 | Leirvogur | LRV | 64.2 | 338.3 | 1962-2010 |
Alibag | ABG | 18.6 | 72.9 | 1922-2010 | Lerwick | LER | 60.1 | 358.8 | 1925-2010 |
Alice Springs | ASP | -23.8 | 133.9 | 1991-2010 | Livingston Island | LIV | -62.7 | 299.6 | 1996-2010 |
Alma Ata | AAA | 43.2 | 76.9 | 1962-2010 | Loparskaya | MMK | 68.2 | 33.1 | 1960-1990 |
Annamalainagar | ANN | 11.4 | 79.7 | 1967-1994 | Lovo | LOV | 59.3 | 17.8 | 1930-2004 |
Apia | API | -13.8 | 188.2 | 1933-2010 | Lunping | LNP | 25.0 | 121.2 | 1980-2000 |
Arctowski | ARC | -62.2 | 301.5 | 1978-1995 | Lvov | LVV | 49.9 | 23.7 | 1957-2010 |
Arti | ARS | 56.4 | 58.6 | 1972-2010 | MBour | MBO | 14.4 | 343.0 | 1952-2010 |
Ascension Island | ASC | -7.9 | 345.6 | 1993-2010 | Macquarie Island | MCQ | -54.5 | 158.9 | 1957-2010 |
Ashkhabad | ASH | 37.9 | 58.1 | 1960-1990 | Manhay | MAB | 50.3 | 5.7 | 1995-2010 |
Baker Lake | BLC | 64.3 | 264.0 | 1951-2010 | Manzhouli | MZL | 49.6 | 117.4 | 1995-2007 |
Bangui | BNG | 4.3 | 18.6 | 1955-2010 | Martin de Vivies | AMS | -37.8 | 77.6 | 1981-2010 |
Bar Gyora | BGY | 31.7 | 35.1 | 1990-2010 | Mawson | MAW | -67.6 | 62.9 | 1963-2010 |
Barrow | BRW | 71.3 | 203.4 | 1964-2010 | Meanook | MEA | 54.6 | 246.7 | 1931-2010 |
Bear Island | BJN | 74.5 | 19.2 | 1987-2006 | Memambetsu | MMB | 43.9 | 144.2 | 1958-2010 |
Beijing | BJI | 40.0 | 116.2 | 1957-2005 | Mirny | MIR | -66.6 | 93.0 | 1956-1997 |
Beijing Ming Tombs | BMT | 40.3 | 116.2 | 1996-2007 | Mizusawa | MIZ | 39.1 | 141.2 | 1980-2010 |
Belsk | BEL | 51.8 | 20.8 | 1966-2010 | Molodezhnaya | MOL | -67.7 | 45.8 | 1967-1977 |
Bereznyaki | KGD | 49.8 | 73.1 | 1965-1976 | Mould Bay | MBC | 76.3 | 240.6 | 1962-1996 |
Borok | BOX | 58.1 | 38.2 | 1980-2010 | Muntinlupa | MUT | 14.4 | 121.0 | 1963-1972 |
Boulder | BOU | 40.1 | 254.8 | 1972-2010 | Nagpur | NGP | 21.1 | 79.0 | 1995-2009 |
Brorfelde | BFE | 55.6 | 11.7 | 1981-2009 | Nagycenk | NCK | 47.6 | 16.7 | 1992-2010 |
Budkov | BDV | 49.1 | 14.0 | 1994-2010 | Narsarsuaq | NAQ | 61.2 | 314.6 | 1968-2009 |
Cambridge Bay | CBB | 69.1 | 255.0 | 1972-2010 | Newport | NEW | 48.3 | 242.9 | 1966-2010 |
Canberra | CNB | -35.3 | 149.4 | 1981-2010 | Niemegk | NGK | 52.1 | 12.7 | 1901-2010 |
Cape Chelyuskin | CCS | 77.7 | 104.3 | 1956-1985 | Novolazarevskaya | NVL | -70.8 | 11.8 | 1961-1978 |
Cape Wellen | CWE | 66.2 | 190.2 | 1956-1987 | Novosibirsk | NVS | 54.8 | 83.2 | 1967-2010 |
Casey | CSY | -66.3 | 110.5 | 1989-2005 | Nurmijarvi | NUR | 60.5 | 24.7 | 1953-2009 |
Chambon-la-Foret | CLF | 48.0 | 2.3 | 1936-2010 | Ottawa | OTT | 45.4 | 284.4 | 1968-2010 |
Changchun | CNH | 43.8 | 125.3 | 1995-2007 | Pamatai | PPT | -17.6 | 210.4 | 1967-2010 |
Changli | CHL | 39.7 | 119.0 | 1995-2007 | Panagjurishte | PAG | 42.5 | 24.2 | 1963-2010 |
Charters Towers | CTA | -20.1 | 146.3 | 1990-2010 | Paratunka | PET | 53.0 | 158.2 | 1969-1995 |
Cheltenham | CLH | 8.7 | 283.2 | 1901-1956 | Phuthuy | PHU | 21.0 | 105.9 | 1996-2010 |
Chengdu | CDP | 31.0 | 103.7 | 1995-2007 | Pilar | PIL | -31.7 | 296.1 | 1941-1980 |
Chongqing | COQ | 29.4 | 106.6 | 1999-2006 | Pleshenitzi | MNK | 54.5 | 27.9 | 1961-1995 |
Chichijima | CBI | 27.1 | 142.2 | 1991-2010 | Pondicherry | PND | 11.9 | 79.9 | 1995-2008 |
College | CMO | 64.9 | 212.1 | 1948-2010 | Port Alfred | CZT | -46.4 | 51.9 | 1974-2009 |
Dalian | DLG | 39.0 | 121.5 | 2000-2007 | Port Moresby | PMG | -9.4 | 147.2 | 1957-1993 |
Dallas | DAL | 33.0 | 263.2 | 1964-1974 | Port Stanley | PST | -51.7 | 302.1 | 1994-2009 |
De Bilt | DBN | 52.1 | 5.2 | 1906-1938 | Port-aux-Francais | PAF | -49.4 | 70.3 | 1957-2009 |
Dedu | DED | 48.6 | 126.1 | 1995-2005 | Poste-de-la-Baleine | PBQ | 55.3 | 282.3 | 1984-2007 |
Del Rio | DLR | 29.5 | 259.1 | 1982-2009 | Qaanaaq | THL | 77.5 | 290.8 | 1947-2010 |
Dikson | DIK | 73.5 | 80.6 | 1957-1986 | Qeqertarsuaq | GDH | 69.3 | 306.5 | 1946-2009 |
Dombas | DOB | 62.1 | 9.1 | 1957-2009 | Qianling | QIX | 34.6 | 108.2 | 1995-2006 |
Dourbes | DOU | 50.1 | 4.6 | 1957-2010 | Resolute Bay | RES | 74.7 | 265.1 | 1956-2010 |
Dumont d’Urville | DRV | -66.7 | 140.0 | 1957-2010 | Rude Skov | RSV | 55.8 | 12.4 | 1927-1981 |
Dusheti | TFS | 42.1 | 44.7 | 1956-2001 | Sable Island | SBL | 43.9 | 300.0 | 1999-2010 |
Dymer | KIV | 50.7 | 30.3 | 1958-1991 | St. Johns | STJ | 47.6 | 307.3 | 1969-2010 |
Ebro | EBR | 40.8 | 0.5 | 1995-2010 | San Fernando | SFS | 36.7 | 354.1 | 1996-2010 |
Eilat | ELT | 29.7 | 34.9 | 1998-2010 | San Juan | SJG | 18.1 | 293.8 | 1921-2010 |
Ekaterinburg | EKT | 56.8 | 60.6 | 1901-1925 | San Pablo-Toledo | SPT | 39.5 | 355.6 | 1996-2010 |
Esashi | ESA | 39.2 | 141.4 | 1997-2010 | Sanae III | SNA | -70.3 | 357.6 | 1961-1990 |
Eskdalemuir | ESK | 55.3 | 356.8 | 1911-2010 | Scott Base | SBA | -77.8 | 166.8 | 1957-2010 |
Eyrewell | EYR | -43.4 | 172.4 | 1980-2010 | Sheshan | SSH | 31.1 | 121.2 | 1932-2010 |
Faraday Islands | AIA | -65.2 | 295.7 | 1957-2010 | Simosato | SSO | 33.6 | 135.9 | 1957-1975 |
Fort Churchill | FCC | 58.8 | 265.9 | 1957-2010 | Sitka | SIT | 57.1 | 224.7 | 1904-2010 |
Fredericksburg | FRD | 38.2 | 282.6 | 1956-2010 | Sodankyla | SOD | 67.7 | 26.6 | 1913-2009 |
Fresno | FRN | 37.1 | 240.3 | 1982-2010 | Stekolnyy | MGD | 60.1 | 151.0 | 1966-1990 |
Fuquene | FUQ | 5.5 | 286.3 | 1955-2010 | Stennis Space Centre | BSL | 30.3 | 270.4 | 1986-2010 |
Furstenfeldbruck | FUR | 48.2 | 11.3 | 1940-2010 | Stepanovka | ODE | 46.8 | 30.9 | 1957-1991 |
Glenlea | GLN | 49.6 | 262.9 | 1984-1997 | Surlari | SUA | 44.7 | 26.3 | 1957-2009 |
Gnangara | GNA | -31.8 | 115.9 | 1957-2010 | Tamanrasset | TAM | 22.8 | 5.5 | 1953-2010 |
Golmud | GLM | 36.4 | 94.9 | 1995-2007 | Tianshui | TSY | 34.6 | 105.9 | 1995-2007 |
Gornotayezhnaya | VLA | 43.7 | 132.2 | 1957-1990 | Tihany | THY | 46.9 | 17.9 | 1957-2009 |
Great Whale River | GWC | 55.3 | 282.2 | 1965-1981 | Tirunelveli | TIR | 8.7 | 77.8 | 1999-2008 |
Guam | GUA | 13.6 | 144.9 | 1957-2010 | Tonghai | THJ | 24.0 | 102.7 | 1995-2007 |
Guangzhou | GZH | 23.1 | 113.3 | 1960-2009 | Trelew | TRW | -43.3 | 294.6 | 1957-2010 |
Guimar | GUI | 28.3 | 343.6 | 1993-2010 | Trivandrum 2 | TRD | 8.5 | 76.9 | 1957-1999 |
Guiyang | GYX | 26.6 | 106.8 | 1995-2005 | Tromso | TRO | 69.7 | 18.9 | 1957-2009 |
Halley Bay | HBA | -75.5 | 333.4 | 1957-1967 | Tsumeb | TSU | -19.2 | 17.6 | 1964-2009 |
Hangzhou | HZC | 30.2 | 120.1 | 1995-2007 | Tucson | TUC | 32.2 | 249.3 | 1910-2010 |
Hartebeesthoek | HBK | -25.9 | 7.7 | 1972-2009 | Ujjain | UJJ | 23.2 | 75.8 | 1980-2003 |
Hartland | HAD | 51.0 | 355.5 | 1957-2010 | Urumqi | WMQ | 43.8 | 87.7 | 1995-2007 |
Hatizyo | HTY | 33.1 | 139.8 | 1986-2009 | Val Joyeux | VLJ | 48.8 | 2.0 | 1901-1936 |
Heiss Island | HIS | 80.6 | 58.0 | 1960-1970 | Valentia | VAL | 51.9 | 349.7 | 1957-2010 |
Hel | HLP | 54.6 | 18.8 | 1966-2010 | Vassouras | VSS | -22.4 | 316.3 | 1915-2010 |
Hermanus | HER | -34.4 | 19.2 | 1941-2010 | Victoria | VIC | 48.5 | 236.6 | 1964-2010 |
Honolulu | HON | 21.3 | 202.0 | 1905-2010 | Vieques | VQS | 18.1 | 294.5 | 1905-1924 |
Hornsund | HRN | 77.0 | 15.5 | 1978-2010 | Visakhapatnam | VSK | 17.7 | 83.3 | 1995-2009 |
Huancayo | HUA | -12.0 | 284.7 | 1921-2010 | Voeikovo | LNN | 59.9 | 30.7 | 1947-1988 |
Hurbanovo | HRB | 47.9 | 18.2 | 1906-2010 | Vostok | VOS | -78.4 | 106.9 | 1958-1979 |
Iqaluit | IQA | 63.8 | 291.5 | 1995-2010 | Vysokaya Dubrava | SVD | 56.7 | 61.1 | 1930-1974 |
Irkutsk | IRT | 52.2 | 104.4 | 1957-2010 | Watheroo | WAT | -30.3 | 115.9 | 1919-1959 |
Istanbul-Kandilli | ISK | 41.1 | 29.1 | 1950-2000 | Wien Kobenzl | WIK | 48.3 | 16.3 | 1957-2005 |
Jaipur | JAI | 26.9 | 75.8 | 1980-209 | Wingst | WNG | 53.7 | 9.1 | 1942-2010 |
Jinghai | JIH | 38.9 | 116.9 | 1995-2007 | Witteveen | WIT | 52.8 | 6.7 | 1938-1987 |
Juyongguan | JYG | 39.8 | 98.2 | 1998-2007 | Wuhan | WHN | 30.5 | 114.6 | 1995-2007 |
Kakadu | KDU | -12.7 | 132.5 | 1995-2010 | Yakutsk | YAK | 62.0 | 129.7 | 1957-2009 |
Kakioka | KAK | 36.2 | 140.2 | 1913-2010 | Yangi Bazar | TKT | 41.3 | 69.6 | 1957-1981 |
Kanoya | KNY | 31.4 | 130.9 | 1958-2010 | Yellowknife | YKC | 62.5 | 245.5 | 1977-2010 |
Kanozan | KNZ | 35.3 | 140.0 | 1961-2010 | Yinchuan | YCB | 38.5 | 106.3 | 1995-2007 |
Kiruna | KIR | 67.8 | 20.4 | 2001-2010 | Yongning | YON | 22.8 | 108.5 | 1996-2006 |
Kourou | KOU | 5.2 | 307.3 | 1996-2010 | Yuzhno Sakhalinsk | YSS | 46.9 | 142.7 | 1957-1988 |
Krasnaya Pakhra | MOS | 55.5 | 37.3 | 1957-2005 | Zaymishche | KZN | 55.8 | 48.8 | 1964-1989 |
L’Aquila | AQU | 42.4 | 13.3 | 1960-2010 |  |  |  |  |  |