The seasonal year is the time between successive recurrences of a seasonal event such as the flooding of a river, the migration of a species of bird, or the flowering of a species of plant.
The need for farmers to predict seasonal events led to the development of calendars. However, the variability from year to year of seasonal events (due to climate change or just random variation) makes the seasonal year very hard to measure. This means that calendars are based on astronomical years (which are regular enough to be easily measured) as surrogates for the seasonal year. For example, the ancient Egyptians used the heliacal rising of Sirius to predict the flooding of the Nile.
A study of temperature records over the past 300 years[1] suggests that the seasonal year is governed by the anomalistic year rather than the tropical year.
This suggestion is surprising because the seasons have been thought to be governed by the tilt of the Earth's axis (see Effect of sun angle on climate). The two types of years differ by a mere 4 days over 300 years, so Thompson's result may not be significant. However, the result is not unreasonable. The seasons can be considered to be an oscillating system driven by two inputs with slightly different frequencies: the total input of energy from the sun varies with the anomalistic year, while the distribution of this energy between the hemispheres varies with the tropical year. In other physical situations, oscillating systems driven by two similar frequencies can latch onto either one. One point that must be considered is that the oscillation arising from the tilt of the axis is much greater than that arising from the distance of the sun.
^Thomson, David (1995-04-07). "The Seasons, Global Temperature, and Precession". Science. 268 (5207): 59–68. Bibcode:1995Sci...268...59T. doi:10.1126/science.268.5207.59. PMID 17755231. S2CID 34475254.
The seasonalyear is the time between successive recurrences of a seasonal event such as the flooding of a river, the migration of a species of bird, or...
the seasonalyear, the fiscal year, the academic year, etc. The term can also be used in reference to any long period or cycle, such as the Great Year. Due...
to a common year. The 366th day (or 13th month) is added to keep the calendar year synchronised with the astronomical year or seasonalyear. Since astronomical...
In time series data, seasonality is the presence of variations that occur at specific regular intervals less than a year, such as weekly, monthly, or...
Calendar reform Common year Fiscal year ISO 8601 ISO week date Leap year Model year Tropical yearSeasonalyear "calendar year". Merriam-Webster. Retrieved...
Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival...
to 5 million cases of severe illness and 290,000 to 650,000 deaths from seasonal flu occur worldwide. Three virus families, Influenza virus A, B, and C...
A seasonal industry is activity within an economic sector in which the majority of operations take place during only part of the year, usually within...
Seasonal adjustment or deseasonalization is a statistical method for removing the seasonal component of a time series. It is usually done when wanting...
Seasonal food refers to the times of the year when the harvest or the flavour of a given type of food is at its peak. This is usually the time when the...
Seasonal lag is the phenomenon whereby the date of maximum average air temperature at a geographical location on a planet is delayed until some time after...
Seasonal affective disorder (SAD) is a mood disorder subset in which people who typically have normal mental health throughout most of the year exhibit...
Seasonal thermal energy storage (STES), also known as inter-seasonal thermal energy storage, is the storage of heat or cold for periods of up to several...
beers. Seasonal beers may be produced when fresh ingredients are available during various seasons, per climatic conditions during the time of the year, and...
Irish low-cost carrier Ryanair serves the following 229 year-round and seasonal destinations in 37 countries as of April 2022. Map showing all destinations...
The Wheel of the Year is an annual cycle of seasonal festivals, observed by a range of modern pagans, marking the year's chief solar events (solstices...
the sky during the summer months, which increases the solar flux. Due to seasonal lag, June, July, and August are the warmest months in the Northern Hemisphere...
ergograph is a graph that shows a relation between human activities and a seasonalyear. The name was coined by Dr. Arthur Geddes of the University of Edinburgh...
29 June 2014. "Seasonal Awards 1993/94". Premier League. Archived from the original on 9 December 2006. Retrieved 29 June 2014. "Seasonal Awards 1994/95"...
Seasonal variation in human birth rate has been found to be a nearly universal phenomenon. Also, birth seasonality has been found to be correlated with...
United States, the efficiency of air conditioners is often rated by the seasonal energy efficiency ratio (SEER) which is defined by the Air Conditioning...
Ashe juniper, Alstonia scholaris Seasonal allergy symptoms are commonly experienced during specific parts of the year, usually during spring, summer or...
governed by the fiscal year it chooses. A business may choose any consistent fiscal year that it wants; however, for seasonal businesses such as farming...
winters and dry summers. Dry and rainy months are characteristic of tropical seasonal forests: in contrast to tropical rainforests, which do not have dry or...
Research on seasonal effects on suicide rates suggests that the prevalence of suicide is greatest during the late spring and early summer months, despite...
snowy landscapes. Among animals, variable snow camouflage is a type of seasonal polyphenism with a distinct winter plumage or pelage. It is found in birds...
are used for data affected by seasonality, when it could be misleading to directly compare different times of the year. SAARs are often used for car sales...
Seasonal human migration is the movement of people from one place or another on a seasonal basis. It occurs most commonly due to seasonal shifts in demand...
Seasonal packaging is a way of marketing a product and sparking sales in consumer segments that infrequently buy the product, by wrapping the product in...
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