Abstract: The concepts of accumulated temperature and heat resources have been widely presented in domestic literature and teaching materials, and accumulated temperature is usually as the main form of representation of heat resource. But its traditional definition obviously violates the principles of physics, and the measurement units also have not been unified. It urgently needs to be given an accurate scientific interpretation and further standardized. Based on the origin and development history of the concepts of accumulated temperature and heat resources, the problems in its practical application are reviewed in this paper, and the application frequency, geographical distribution characteristics of the term of accumulated temperature and its synonyms through Web of Science related literature are statistically analyzed and compared. The results show that, although accumulated temperature is the main indicator of traditional term of agricultural heat resources and is widely used, however, in fact, plants and cold-blooded animals do not need a certain amount of heat energy to complete a certain stage of growth and development, but require suitable temperature conditions and necessary duration. Excessive heat or too high temperature will cause damage to organisms, and some species even require relatively lower temperatures. On the other hand, literature search and statistics show that the term “accumulated temperature” has been rarer and rarer used in the international academic communities now, and the term “heat resource” is also rarely used in authoritative agricultural meteorological literature. In order to promote a more accurate and scientific term, it is recommended to stop use of the term “accumulated temperature” in Chinese Scientific Journals and to change into "integrated temperature" or "thermal time". And the unit should be unified into "℃·d" or “℃·h” and not “℃”. The term of “heat resource” is also changed to “temperature resource” and broadened, i.e. the synthesis of temperature conditions and their duration conducive to growth and development of plants and cold-blood animals. It will give full scientific significance without affecting the large number of applications and achievements of the current accumulated temperature theory, and will promote further development of agricultural meteorology and related disciplines.

Key words: Thermal time, Degree-day, Accumulated temperature, Heat resource, Measuring unit, Scientificalness