Statistical modeling for the monthly estimate of chilling hours and units in Plateau regions of Rio Grande do Sul and Santa Catarina

ABSTRACT The objective of this study was to obtain and evaluate models for the monthly estimation of chilling hours/units based on air temperature data in the Plateau regions of Rio Grande do Sul and Santa Catarina. Data of air temperature were used from May to August 2012 to 2017 of seven meteorological stations. For each month the chilling hours/unit were calculated by the Utah method and the sum of temperatures lower or equal to 7.2 °C that were correlated with the minimum and average monthly temperature with the use of the Regression Analysis. Six statistical methods were used to evaluate the monthly estimate of chilling hours/units obtained by previously obtained models. The minimum temperature and the monthly average explained between 65% and 96% of the chilling hours by the temperature threshold ≤ 7.2 °C and the chilling units by the Utah method. The minimum temperature and the monthly air average are recommended for the estimation of chilling hours and chilling units, respectively. The climatic variability of the winter in the study region results in different performances of the models of estimates of chilling hours/unit.

摘要 本研究旨在基于南里奥格兰德州与圣卡塔琳娜州高原地区的气温数据，构建并评估用于月度低温小时/低温单位（chilling hours/units）估算的模型。本研究采用了2012年至2017年5-8月间7个气象站点的气温观测数据。每月的低温小时/低温单位分别通过犹他法（Utah Method）以及≤7.2℃的温度总和进行计算，并将计算结果与月最低气温、月平均气温通过回归分析进行关联。采用6种统计方法对通过前期构建模型得到的月度低温小时/低温单位估算结果进行评估。对于温度阈值≤7.2℃对应的低温小时以及采用犹他法计算的低温单位，月最低气温与月平均气温的变异解释率分别介于65%至96%之间。研究建议分别采用月最低气温与月平均气温来估算低温小时与低温单位。研究区域冬季的气候变异性会导致低温小时/低温单位估算模型的表现存在差异。