Yizhi Han , Salvatore Calabrese , Huihua Du , Jun Yin
{"title":"评估不同时间尺度下彭曼蒸发蒸腾率和彭曼-蒙蒂斯蒸发蒸腾率的偏差","authors":"Yizhi Han , Salvatore Calabrese , Huihua Du , Jun Yin","doi":"10.1016/j.jhydrol.2024.131534","DOIUrl":null,"url":null,"abstract":"<div><p>The Penman and Penman–Monteith equations are widely used for estimating surface evapotranspiration (ET) at regional and global scales. These nonlinear equations were derived from the turbulent transport of heat fluxes and, in theory, need to be applied to a temporal scale ranging from half hour to an hour. However, these equations have been frequently applied with hydrometeorological variables averaged at daily, monthly, and even decadal time intervals, resulting in biases due to their nonlinearities. In this study, we used global reanalysis data and Taylor expanded Penman and Penman–Monteith equations to explore their nonlinear components and the biases associated with the timescale mismatches. We found that global average biases for approximating Penman equation range from 0.72 to 1.31 mm day<sup>−1</sup> from daily to annual timescales, which mainly stem from the temperature–radiation, temperature–vapor pressure deficit (VPD), and aerodynamic conductance–VPD covariances. For Penman–Monteith equation, the corresponding biases vary from 0.47 to 0.53 mm day<sup>−1</sup>, which may be associated with the addition of stomatal conductance–VPD covariances. As a reference, the global averages from Penman and Penman–Monteith at hourly timescale over one year are 7.1 and 1.7 mm day<sup>−1</sup>. Large biases also exist around the world across various climate zones, where one or multiple covariances between meteorological variables makes the first-order approximations of Penman and Penman–Monteith equations less accurate. This analysis serves as a reminder of nonlinearities in Penman and Penman–Monteith equations, hence the requirement of data at high temporal resolution for estimating potential or actual evapotranspiration.</p></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":null,"pages":null},"PeriodicalIF":5.9000,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Evaluating biases in Penman and Penman–Monteith evapotranspiration rates at different timescales\",\"authors\":\"Yizhi Han , Salvatore Calabrese , Huihua Du , Jun Yin\",\"doi\":\"10.1016/j.jhydrol.2024.131534\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The Penman and Penman–Monteith equations are widely used for estimating surface evapotranspiration (ET) at regional and global scales. These nonlinear equations were derived from the turbulent transport of heat fluxes and, in theory, need to be applied to a temporal scale ranging from half hour to an hour. However, these equations have been frequently applied with hydrometeorological variables averaged at daily, monthly, and even decadal time intervals, resulting in biases due to their nonlinearities. In this study, we used global reanalysis data and Taylor expanded Penman and Penman–Monteith equations to explore their nonlinear components and the biases associated with the timescale mismatches. We found that global average biases for approximating Penman equation range from 0.72 to 1.31 mm day<sup>−1</sup> from daily to annual timescales, which mainly stem from the temperature–radiation, temperature–vapor pressure deficit (VPD), and aerodynamic conductance–VPD covariances. For Penman–Monteith equation, the corresponding biases vary from 0.47 to 0.53 mm day<sup>−1</sup>, which may be associated with the addition of stomatal conductance–VPD covariances. As a reference, the global averages from Penman and Penman–Monteith at hourly timescale over one year are 7.1 and 1.7 mm day<sup>−1</sup>. Large biases also exist around the world across various climate zones, where one or multiple covariances between meteorological variables makes the first-order approximations of Penman and Penman–Monteith equations less accurate. This analysis serves as a reminder of nonlinearities in Penman and Penman–Monteith equations, hence the requirement of data at high temporal resolution for estimating potential or actual evapotranspiration.</p></div>\",\"PeriodicalId\":362,\"journal\":{\"name\":\"Journal of Hydrology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.9000,\"publicationDate\":\"2024-07-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Hydrology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022169424009302\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, CIVIL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hydrology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022169424009302","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
Evaluating biases in Penman and Penman–Monteith evapotranspiration rates at different timescales
The Penman and Penman–Monteith equations are widely used for estimating surface evapotranspiration (ET) at regional and global scales. These nonlinear equations were derived from the turbulent transport of heat fluxes and, in theory, need to be applied to a temporal scale ranging from half hour to an hour. However, these equations have been frequently applied with hydrometeorological variables averaged at daily, monthly, and even decadal time intervals, resulting in biases due to their nonlinearities. In this study, we used global reanalysis data and Taylor expanded Penman and Penman–Monteith equations to explore their nonlinear components and the biases associated with the timescale mismatches. We found that global average biases for approximating Penman equation range from 0.72 to 1.31 mm day−1 from daily to annual timescales, which mainly stem from the temperature–radiation, temperature–vapor pressure deficit (VPD), and aerodynamic conductance–VPD covariances. For Penman–Monteith equation, the corresponding biases vary from 0.47 to 0.53 mm day−1, which may be associated with the addition of stomatal conductance–VPD covariances. As a reference, the global averages from Penman and Penman–Monteith at hourly timescale over one year are 7.1 and 1.7 mm day−1. Large biases also exist around the world across various climate zones, where one or multiple covariances between meteorological variables makes the first-order approximations of Penman and Penman–Monteith equations less accurate. This analysis serves as a reminder of nonlinearities in Penman and Penman–Monteith equations, hence the requirement of data at high temporal resolution for estimating potential or actual evapotranspiration.
期刊介绍:
The Journal of Hydrology publishes original research papers and comprehensive reviews in all the subfields of the hydrological sciences including water based management and policy issues that impact on economics and society. These comprise, but are not limited to the physical, chemical, biogeochemical, stochastic and systems aspects of surface and groundwater hydrology, hydrometeorology and hydrogeology. Relevant topics incorporating the insights and methodologies of disciplines such as climatology, water resource systems, hydraulics, agrohydrology, geomorphology, soil science, instrumentation and remote sensing, civil and environmental engineering are included. Social science perspectives on hydrological problems such as resource and ecological economics, environmental sociology, psychology and behavioural science, management and policy analysis are also invited. Multi-and interdisciplinary analyses of hydrological problems are within scope. The science published in the Journal of Hydrology is relevant to catchment scales rather than exclusively to a local scale or site.