Faculty of Geography, Babeş-Bolyai University, 5-7, Clinicilor Street, 400006, Cluj-Napoca, Romania.
SC Eco Maps SRL, 2C, Someşului Street, Ent. 1, Apt. 6, 407280, Florești, Romania.
Int J Biometeorol. 2019 Apr;63(4):499-510. doi: 10.1007/s00484-019-01681-6. Epub 2019 Jan 31.
Climate change has profound environmental and socio-economic implications. To analyze climate change in relation to crops, a wide variety of agro-climatic indices has been proposed by the scientific community. In this study, changes in a set of 12 agro-climatic indices related to temperature were investigated in Central Chile over a 56-year period (1961-2016). The indices were computed based on data referring to daily maximum and minimum temperatures (TX and TN). They were organized in two categories: (1) cold- and (2) heat-related indices. Cold-related indices consisted of first frost day (FFD), last frost day (LFD), frost period (FP), number of frost days (FD), accumulated frost (AF), and number of days when TN is below - 2 °C (FD-2). Heat-related indices included the growing degree day (GDD) index, calculated based on four thresholds which measure the available heat resources for a wide variety of plants with different thermal requirements, and two heat stress indices which quantify the number of days with TX above 25 °C (plant heat stress (PHS)) and above 30 °C (plant high heat stress (PHHS)). Changes in agro-climatic indices were investigated using the Mann-Kendall test and the Sen's slope estimator. The main results revealed that the FFD occurred later, while LFD occurred earlier, thus determining a shortening of the FP in the northern half of the studied area. Trends in FD, AF, and FD-2 indices generally indicated warmer conditions in terms of TN during the cold period of the year. Agro-climatic indices related to heat showed important changes in Central Chile. Thus, statistically, the majority of trends become significant and indicated enhanced condition for crops in respect of GDD indices. However, from the heat stress perspective, the analyzed indices showed that conditions become worse in most of the studied locations for crops sensible to temperatures higher than 25 and 30 °C.
气候变化对环境和社会经济具有深远影响。为了分析与作物有关的气候变化，科学界提出了各种各样的农业气候指数。在本研究中，对智利中部 56 年来（1961-2016 年）与温度有关的 12 个农业气候指数的变化进行了研究。这些指数是根据每日最高和最低温度（TX 和 TN）的数据计算得出的。它们分为两类：（1）与寒冷有关的指数和（2）与炎热有关的指数。与寒冷有关的指数包括初霜日（FFD）、终霜日（LFD）、霜期（FP）、霜日数（FD）、累积霜量（AF）和 TN 低于-2°C 的天数（FD-2）。与炎热有关的指数包括生长度日（GDD）指数，该指数基于四个阈值计算，这些阈值衡量了各种具有不同热需求的植物可利用的热量资源，以及两个热量应激指数，用于量化 TX 高于 25°C（植物热应激（PHS））和高于 30°C（植物高热应激（PHHS））的天数。使用 Mann-Kendall 检验和 Sen 的斜率估计器研究了农业气候指数的变化。主要结果表明，北部地区的 FFD 发生得较晚，而 LFD 发生得较早，因此确定了 FP 的缩短。FD、AF 和 FD-2 指数的趋势通常表明，在一年中较冷的时期，TN 温度较暖。与炎热有关的农业气候指数在智利中部发生了重要变化。因此，从统计学上讲，大多数趋势变得显著，并表明 GDD 指数的作物条件得到改善。然而，从热应激的角度来看，分析的指数表明，在大多数研究地点，对温度高于 25°C 和 30°C 敏感的作物的条件变得更糟。
