The phrase "a solar year" is correct and usable in written English.
It can be used when referring to the length of time it takes for the Earth to complete one orbit around the Sun, typically about 365.25 days.
Example: "The calendar is based on a solar year, which is why we have a leap year every four years to account for the extra day."
Alternatives: "a calendar year" or "a year based on the sun".
(The Iranian calendar, however, is based on a solar year).
A solar year is about 365 1/4 days, or about 52 weeks and 1 1/4 days.
While the Gregorian calendar is based on the solar day, the traditional Chinese calendar is lunisolar — a solar year subdivided into lunar cycles of 29.53 days.
Though the sun was created during the vernal equinox, a solar year is not precisely 365 1/4 days, but a few minutes less.
As a lunar year is approximately 11 days shorter than a solar year, a leap month is added at regular intervals to preserve the match with the cycle of the seasons.
Some scholars suggest that a solar year prevailed in ancient Israel, but no convincing proofs have been offered, and it is more likely that a lunisolar calendar similar to that of ancient Babylonia was used.
The year consists of 19 months, each having 19 days, with four or five intercalary days, to make a full solar year.
Ah, but there is a subtle difference in these two representations of a "year". The time length of Earth's orbit around the Sun is called a "tropical" or "solar" year.
The Kiso nightglow data, is a valuable dataset presenting 16 year long observations of the oxygen green line nightglow emission rate from 1979, a solar maximum year, through 1989, the next solar maximum year, to 1994.
For example, Babylonian arithmetical procedures used for computing lunar and solar phenomena turn up in conjunction with a length for the solar year due to Hipparchus.
Since the lunar calendar was 10 or 11 days shorter than the solar year, a 13th month (called Thoth) was intercalated every several years to keep the lunar calendar in rough correspondence with the agricultural seasons and their feasts.
