The variability and seasonality in the ratio of photosynthetically active radiation to solar radiation: A simple empirical model of the ratio
The variability and seasonality in the ratio of photosynthetically active radiation to solar radiation: A simple empirical model of the ratio
复制标题
DOI：
10.1016/j.jag.2022.102724
复制
发表时间：
2022-04
期刊：
影响因子：
--
通讯作者：
T. Akitsu;K. Nasahara;Osamu Ijima;Yasuo Hirose;R. Ide;K. Takagi;A. Kume
中科院分区：
文献类型：
--
作者：
T. Akitsu;K. Nasahara;Osamu Ijima;Yasuo Hirose;R. Ide;K. Takagi;A. Kume
在许多生态学研究中，光合有效辐射（PAR）与太阳辐射（SR）的比值恒定（约0.45-0.46），通过增殖将SR转化为PAR。常数比是有用和方便的。然而，对于这一比率是0.45还是0.46，以及在全球范围内的分布情况，人们并没有达成普遍共识。因此，报告了许多局部经验比率。本研究旨在展示该比率的全球分布及其变化范围。因此，我们创建了两个简单的经验模型来估计基于他们的现场数据的比例，以达到目的。该模型基于在日本筑波馆野用直接和扩散分离方法观测到的SR和PAR的精确数据。在日本的三个验证点，该比率的估计误差在3%以内，与使用常数的15%相比有了相当大的降低。数值模型也产生了误差在3%左右的比率。利用提出的模型，我们证明了该比率的年平均值在0.409到0.477之间。当使用定比时，结果将有助于不确定度的估计。
A constant ratio of photosynthetically active radiation (PAR) to solar radiation (SR) (about 0.45–0.46) has been used in many ecological studies to convert SR into PAR by multiplication. The constant ratio is useful and convenient. However, there is no general agreement on whether the ratio is 0.45 or 0.46 and how distributed globally. Accordingly, many local empirical ratios have been reported. This study aims to demonstrate a global distribution of the ratio and its changing range. Thus, we created two simple empirical models to estimate the ratio based on thein-situclimatic data to achieve the aim. The models were created based on accurate data of SR and PAR observed using a direct and diffuse separation method at Tateno in Tsukuba, Japan. At three validation sites in Japan, the ratio could be estimated with an error within 3%, a considerable reduction from 15% in using a constant. The numerical model also produced the ratio within approximately 3% errors. Using the proposed model, we demonstrated that the annual mean of the ratio had a range from 0.409 to 0.477. The results will contribute to the uncertainty estimation when using a constant ratio.