Singularity (climate)
Encyclopedia
A singularity is a weather phenomenon likely to occur with reasonable regularity around a specific approximate calendar date.
The concept should not be confused with more general seasonal weather patterns. For example the British tradition that rain on St. Swithun's Day (15 July) will be followed by forty days and nights of rain would (if true) represent a singularity, but the fact that May Day
is usually warmer than New Year's Day
in northern
locales is not.
Although folk tales such as St Swithun's Day generally have little credibility, some of these events have a more solid basis. Early scientific investigation involved the creation of calendars of singularities based on temperature and rainfall anomalies. Later and more successful work by Hubert Lamb
of the Climatic Research Unit
was based on air circulation patterns. Lamb's work analysed daily frequency of airflow categories between 1898 and 1947. Similar work was carried out by Flohn
and Hess in central Europe based on analysis of air flows from 1881 to 1947.
A 1955 study by Liverpool Observatory and Tidal Institute
analysed maximum daily temperatures at a single location from 1900 to 1953. This found problems when attempting to demonstrate the statistical significance of apparent temperature anomalies.
In the 1950s, E.G. Bowen
suggested that some rainfall calendaricities might be explicable in terms of meteoric particles from cometary orbits acting as ice nuclei in terrestrial clouds; his theory received support from a number of sources
However, such work has now fallen out of favour due to modern dynamic modelling techniques, although articles are still appearing (e.g., by Godfrey et al.) which suggest that at least some observed singularities are genuine phenomena.
The concept should not be confused with more general seasonal weather patterns. For example the British tradition that rain on St. Swithun's Day (15 July) will be followed by forty days and nights of rain would (if true) represent a singularity, but the fact that May Day
May Day
May Day on May 1 is an ancient northern hemisphere spring festival and usually a public holiday; it is also a traditional spring holiday in many cultures....
is usually warmer than New Year's Day
New Year's Day
New Year's Day is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar used in ancient Rome...
in northern
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
locales is not.
Although folk tales such as St Swithun's Day generally have little credibility, some of these events have a more solid basis. Early scientific investigation involved the creation of calendars of singularities based on temperature and rainfall anomalies. Later and more successful work by Hubert Lamb
Hubert Lamb
Hubert Horace Lamb was an English climatologist who founded the Climatic Research Unit in 1972 in the School of Environmental Sciences at the University of East Anglia.-Career:...
of the Climatic Research Unit
Climatic Research Unit
The Climatic Research Unit is a component of the University of East Anglia and is one of the leading institutions concerned with the study of natural and anthropogenic climate change....
was based on air circulation patterns. Lamb's work analysed daily frequency of airflow categories between 1898 and 1947. Similar work was carried out by Flohn
Hermann Flohn
Hermann Flohn was "one of the world greatest climatologists". Flohn was professor at the University of Bonn and head of the department at the Institute of Meteorology of Bonn University. He produced about 360 publications...
and Hess in central Europe based on analysis of air flows from 1881 to 1947.
A 1955 study by Liverpool Observatory and Tidal Institute
Proudman Oceanographic Laboratory
The former Proudman Oceanographic Laboratory is based in Brownlow Street, Liverpool, England. In April 2010, POL merged with the National Oceanography Centre, Southampton to form the National Oceanography Centre National Oceanography Centre...
analysed maximum daily temperatures at a single location from 1900 to 1953. This found problems when attempting to demonstrate the statistical significance of apparent temperature anomalies.
In the 1950s, E.G. Bowen
Edward George Bowen
Edward George 'Taffy' Bowen, CBE, FRS was a British physicist who made a major contribution to the development of radar, and so helped win both the Battle of Britain and the Battle of the Atlantic...
suggested that some rainfall calendaricities might be explicable in terms of meteoric particles from cometary orbits acting as ice nuclei in terrestrial clouds; his theory received support from a number of sources
However, such work has now fallen out of favour due to modern dynamic modelling techniques, although articles are still appearing (e.g., by Godfrey et al.) which suggest that at least some observed singularities are genuine phenomena.