Fine-scale mapping of daily minimum temperature in a cropland with complex terrains through the combination of a cold flow accumulation model with inversion strength
Fine-scale mapping of daily minimum temperature in a cropland with complex terrains through the combination of a cold flow accumulation model with inversion strength
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DOI：
10.1016/j.agrformet.2022.109247
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发表时间：
2023-02
影响因子：
6.2
通讯作者：
Kensuke Kimura;A. Maruyama;K. Sasaki;K. Kudo;Eri Tanaka;Erina Fushimi;H. Nakagawa
中科院分区：
文献类型：
--
作者：
Kensuke Kimura;A. Maruyama;K. Sasaki;K. Kudo;Eri Tanaka;Erina Fushimi;H. Nakagawa
在复杂地形下，由于冷空气的排放，最低温度在细空间尺度上变化。这导致植物物候事件和霜冻风险的空间变异性很大。各种地形变量已被用来模拟冷空气排放及其对温度的影响。在这项研究中，我们使用流量累积（FA）修改了传统方法。首先，我们开发了一个新的算法FA重新考虑有效领域的冷空气排水。这使我们能够提高模型的适用性。FA模型，然后结合垂直梯度的位温，这代表逆温强度稳定，夜间条件。这一过程有助于在给定日期和时间点估计最低温度。该模型是利用复杂地形的茶园温度观测数据开发的，由于气候变化，霜冻风险正在增加。15个观测点的日最低气温最大差异为6.7°C，尽管海拔差异只有73米。与仅使用空间插值的模型相比，该模型产生了更好的日最低温度时空变化的估计，并将山谷地区的估计和测量温度之间的平均残差从1.9提高到0.03°C。与传统算法相比，该算法提高了脊区温度估计的准确性，明确了脊区和谷区的边界。我们的方法可以有助于时空分析温度变化和随之而来的物候事件和霜冻风险在复杂地形的变化。
In complex terrains, the minimum temperature varies at fine spatial scales owing to cold air drainage. This leads to large spatial variabilities in phenological events and frost risk in plants. Various topographic variables have been used to model cold air drainage and its influence on temperature. In this study, we modified a conventional approach using flow accumulation (FA). First, we developed a new algorithm for FA by reconsidering effective areas of cold air drainage. This allowed us to increase the model's applicability. The FA model was then combined with the vertical gradient of potential temperature, which represents the inversion strength during stable, nighttime conditions. This process facilitated minimum temperature estimation at a given date and point. The model was developed using temperature observations in tea fields with complex terrains, where frost risk is increasing due to climate change. The maximum difference in daily minimum temperature across 15 observation points was 6.7°C, despite only a 73-m elevation difference. Compared with models using spatial interpolation alone, the proposed model produced a better estimate of the spatiotemporal variability of daily minimum temperature and improved the average residuals between estimated and measured temperatures in valley areas from 1.9 to 0.03°C. Moreover, compared to the conventional algorithm, the proposed algorithm improved temperature estimations in ridge areas and clarified the boundaries between ridges and valleys. Our approach could contribute to the spatiotemporal analysis of temperature variations and concomitant changes in phenological events and frost risk in complex terrains.