ON THE VARIATION OF ACCUMULATED TEMPERATURE DURING THE LAST 100 YEARS AND CROP YIELD IN CHINA
Wang Fu-tang (Academy of Meteorological Science, Central Meteorological Service)
Based on the collecting and processing of the long series data of accumulated temperature and crop yield in our country, this article analyses the variation of the classes of deviation of effective accumulated temperature 10癈 during the last 100 ye ars, and the meteorological association with the meteorological yield variation of the main crop during the last 30 years in Shanghai and other places. 1. There are specific fluctuations with different periods for the variation of ac-cumulated temperature in different regions and it will affect agricultural development to a certain extent. The above mentioned periodic fluctuation will only make a little turbulence on the curve of accumulated temperature for short time- warming and cooling but it cannot change the general trend. 2. The crop meteorological yield not only depends on the environmental-meteor-ological conditions but also on the rule of crop yield variation itself and from the periodic fluctuation in the variation of the meteorological yield such as 12 years period which makes the evaluation of prediction more complicated. 3. In comparing the periodogram analysis of cla.sses of meteorological yield with that of classes of deviation of accumulated temperature in different periods during the last 30 years. There is a corresponding periodicity between them. It also shows that the periodic variation of agrometeorological thermal conditions may effect the periodic variation of crop yield to certain extent. In reference (1) the author suggested that agrometeorological thermal factor, as one of the main environmental conditions for crop planting and development, is one of the main reasons for periodic fluctuation in yield series serious. The above analysis in this paper preliminarily proves the existance of this relationship.