Case study on the effectiveness of Agrometeorological Proverbs

Abstract

Many agrometeorological proverbs unique created by Chinese ancestors imply the relationship between universe, season, climate and agriculture events, which have been past considered as the valuable weather calendar to guide the agriculture events in China for thousands of years. And subject to the variation among various regions with distinguished climate or agricultural conditions, there is a requirement to examine the scientificity and applicability of agrometeorological proverbs before guiding the agriculture management. Based on the daily meteorological data of 206 meteorological stations in the Yangtze River Basin from 1966 to 2019, this paper explored the scientificity of meteorological knowledge embedded in meteorological proverbs “The Beginning of Spring at both ends resulting in hot in the dog days” and their applicability in the context of climate change. The study firstly investigated the warming rate based on the least-square method to fit the temperature data curves of the Beginning of Spring- Minor Heat in the Beginning of Spring at both Ends Years (BSEY) and Normal Years (NY), and to classify the “Fast Warming” (FW) temporal period according to the criteria that the days with a slope of warming of BSEY is greater than the slope of warming of NY in a certain temporal period, which accounts for more than 65% of the total number of days in the temporal period; Furthermore, the differences between BSEY and NY in the “Hot Dog Days ”(HDD) phase were compared and analyzed according to the inter-decadal precipitation and the different “ Heat levels” criteria defined by the difference of the Temperature-Humidity Index (THI) between the two years. Results shows that: (1) all regions in the Yangtze River basin, except for the plateau areas, are in line with the “FW” characteristic, accounting for 69% of the Yangtze River basin area, and the temporal period in which the “FW” characteristic appears (46 days after the Beginning of Spring) is before the the Spring Equinox. (2) There are areas in the upper, middle and lower reaches of the Yangtze River basin that meet the “HDD” characteristics, with the strongest compliance in the lower reaches, accounting for 90% of the lower reaches, and differences in the non-compliant areas, except for the Qinghai-Tibetan alpine region, mainly due to the influence of mountain ranges and other topography. In summary, the proverb is suitable for the main circulation regions in terms of applicability, and meteorological knowledge behind the proverb is also scientificity appropriate in the region where it is used. Meanwhile, this study can provide a reference for future policy development, agriculture-related research, and proper arrangement of agricultural production.