A comparison of models for estimating potential evapotranspiration for Florida land cover types

Douglas, Ellen; Jacobs, Jennifer M.; Sumner, David M.; Ray, Ram L.

doi:10.1016/j.jhydrol.2009.04.029

Cited by 133 publications

(113 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our simulations with the stomatal optimization model predict that a doubling of present CO 2 will decrease the annual transpiration flux from subtropical vegetation in Florida by ≈60 W·m −2 . This decrease is considerable because the current annual evapotranspiration flux in Florida is ≈120 W·m −2 and transpiration constitutes ≈50% of this total (12,30). Feedbacks at regional and continental scale could potentially compensate for reduced canopy transpiration and shift the fractional contribution away from transpiration (31).…”

Section: Discussionmentioning

confidence: 99%

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO ₂

Boer

Lammertsma

Wagner-Cremer

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

146

102

View full text Add to dashboard Cite

Plant physiological adaptation to the global rise in atmospheric CO 2 concentration (CO 2 ) is identified as a crucial climatic forcing. To optimize functioning under rising CO 2 , plants reduce the diffusive stomatal conductance of their leaves (g s ) dynamically by closing stomata and structurally by growing leaves with altered stomatal densities and pore sizes. The structural adaptations reduce maximal stomatal conductance (g smax ) and constrain the dynamic responses of g s . Here, we develop and validate models that simulate structural stomatal adaptations based on diffusion of CO 2 and water vapor through stomata, photosynthesis, and optimization of carbon gain under the constraint of a plant physiological cost of water loss. We propose that the ongoing optimization of g smax is eventually limited by species-specific limits to phenotypic plasticity. Our model reproduces observed structural stomatal adaptations and predicts that adaptation will continue beyond double CO 2 . Owing to their distinct stomatal dimensions, angiosperms reach their phenotypic response limits on average at 740 ppm and conifers on average at 1,250 ppm CO 2 . Further, our simulations predict that doubling today's CO 2 will decrease the annual transpiration flux of subtropical vegetation in Florida by ≈60 W·m −2 . We conclude that plant adaptation to rising CO 2 is altering the freshwater cycle and climate and will continue to do so throughout this century.climate change | physiological forcing | plant evolution P lants respond to the complex of environmental signals they perceive by plastic changes in their phenotype to increase individual fitness (1). The most apparent environmental change that induces phenotypic adaptations in plants is the global increase in atmospheric CO 2 concentration (CO 2 ) (2). In response to this rise in CO 2 , plants reduce the diffusive stomatal conductance of their leaves [g s (mol·m −2 ·s −1 )] to increase drought resistance (3) and reduce physiological costs associated with water transport (4). Plants can reduce g s by dynamically closing their stomata within minutes (5, 6), and structurally within the lifespan of an individual by growing leaves with altered stomatal density [D (number of stomata·m −2 )] and pore size at maximal stomatal opening [a max (m 2 )] (7, 8). Structural adaptations thereby reduce maximal stomatal conductance [g smax (mol·m −2 · s −1 )], which critically reduces actual g s , especially when stomata are fully open during times with ample light and water (9).Reduction of g s via structural adaptation of g smax has the potential to reduce transpiration fluxes and, thus, cause land surface warming in addition to changes in the global hydrological cycle with rising CO 2 (10). This climatic effect is termed the physiological forcing of CO 2 , which acts beside and independent of its radiative forcing. Despite advances to quantify this physiological forcing with global climate models (11, 12), these models rely on semiempirical relations to simulate g s from environmental variables (...

show abstract

Section: Discussionmentioning

confidence: 99%

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO ₂

Boer

Lammertsma

Wagner-Cremer

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

146

102

View full text Add to dashboard Cite

show abstract

“…Apesar de a série histórica ter sido pequena, a indisponibilidade de informações para estudos dessa natureza tem feito com que diversos deles sejam desenvolvidos com séries ainda menores (Douglas et al, 2009;Sentelhas et al, 2010).…”

Section: Methodsunclassified

Estimativa da evapotranspiração de referência a partir de dados meteorológicos limitados

Carvalho

Rocha

Bonomo

et al. 2015

Pesq. agropec. bras.

View full text Add to dashboard Cite

Resumo -O objetivo deste trabalho foi avaliar a estimativa da evapotranspiração de referência (ETo), para a região Sudeste do Brasil, a partir de dados meteorológicos limitados. O método de Penman-Monteith FAO 56 (PM p ) foi tomado como referência. Três cenários com dados meteorológicos limitados, obtidos de rede de estações automáticas, foram utilizados para estimação da ETo: método padrão (PM p ) com uso da radiação solar estimada pelo balanço entre ondas curtas e longas (PM Krs ); método padrão com uso da pressão de vapor estimada pelas temperaturas máxima e mínima, e pela umidade relativa do ar (PM ea ); e método padrão com uso da velocidade de vento constante (2 m s -1 ; PM u2 ). A ETo também foi estimada pelos métodos de Hargreaves-Samani (HS) e de Turc. Os modelos foram analisados por meio de indicadores estatísticos de desvio absoluto médio (MBE), erro relativo (ER), raiz quadrada do erro quadrático médio (RMSE) e índice de Willmott (d). O método PM ea é a melhor alternativa para estimar a ETo, seguido pelos métodos PM u2 , para Espírito Santo e Rio de Janeiro, e PM Krs , para São Paulo e Minas Gerais. Os maiores erros são obtidos com o método de Hargreaves-Samani, que superestimou a ETo em comparação ao PM p , para a maioria das estações avaliadas.Termos para indexação: Hargreaves-Samani, mínimo de dados, Penman-Monteith, radiação solar, Turc, velocidade do vento. Estimating reference evapotranspiration with limited meteorological dataAbstract -The objective of this work was to evaluate the estimate of reference evapotranspiration (ETo) for the Southeast Region of Brazil using limited meteorological data. The FAO 56 Penman-Monteith method (PM p ) was used as reference. Three scenarios of limited meteorological data, obtained from automatic network stations, were used for estimating ETo: standard method (PM p ), with solar radiation estimated from the balance between short and wide wavelengths (PM Krs ); standard method using vapor pressure estimated from minimum and maximum temperatures, and from air relative humidity (PM ea ); and standard method using constant wind speed (2 m s -1 ; PM u2 ). ETo was also estimated by the Hargreaves-Samani (HS) and Turc methods. The models were analyzed by statistical indicators of mean absolute deviation (MBE), relative error (RE), root mean square error (RMSE), and Willmott index (d). The PM ea method is the best alternative to estimate ETo, followed by PM u2 , for the states of Espírito Santo and Rio de Janeiro, and PM Krs , for the states of São Paulo and Minas Gerais. The largest errors are obtained with the Hargreaves-Samani method, which overestimated ETo compared with PM p , for most of the evaluated stations.

show abstract

“…This approach is similar to the one used in other Ep studies on eddy-covariance or lysimeter data, in which the Bowen ratio (e.g. Douglas et al, 2009) …”

Section: Selection Of Unstressed Daysmentioning

confidence: 99%

“…insect plagues, phenological leaf-out, fires, heat and atmospheric dryness stress, nutrient limitations). In addition, surface soil moisture can be a poor indicator of water stress, as rooting depth can vary and is not accurately measured, and different plants may exhibit various strategies and responses to water stress (Miralles et al, 2011a;Douglas et al, 2009;Powell et al, 2006;Martínez-Vilalta et al, 2014). This is confirmed by our results: sampling unstressed days based on the energy balance-based criterion resulted 5 in higher correlations (Table S5 vs Table S2) between Ep and Eunstr for all methods and in lower unRMSE, with the exception of the temperature-based methods (Table S6 vs Table S3).…”

Section: Comparison Of Criteria To Define Unstressed Days 35mentioning

confidence: 99%

“…Pan evaporation data, available in larger volumes and at larger scales, have also been used (Donohue et al, 2010;Zhou et al, 2006;McVicar et al, 2012) but provide a proxy of open-water evaporation, rather than actual ecosystem potential evaporation, and also exhibit biases related to the location, shape and composition of the instrument (Pettijohn and Salvucci, 2009). Eddy 10 covariance measurements, finally, are an attractive alternative, but have so far been used in a relatively limited number of studies focusing on local or regional scale only (Douglas et al, 2009;Li et al, 2016;Jacobs et al, 2004;Sumner and Jacobs, 2005).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Potential evaporation at eddy-covariance sites across the globe

Maes¹,

Gentine²,

Verhoest³

et al. 2018

Preprint

View full text Add to dashboard Cite

Abstract. Potential evaporation (Ep) is a crucial variable for hydrological forecast and in drought monitoring systems. However, multiple interpretations of Ep exist, and these reflect a diverse range of methods to calculateEp. As such, a comparison of the performance of these methods against field observations in different global ecosystems is badly needed. In this study, we used eddy-covariance measurements from 107 sites of the FLUXNET2015 database, covering 11 different biomes, to parameterize and compare the main Ep methods and 10 uncover their relative performance. For each site, we extracted the days for which ecosystems are unstressed based on both an energy balance approach and on a soil water content approach. The evaporation measurements during these days were used as reference to validate the different methods to estimate Ep. Our results indicate that a simple radiation-driven method calibrated per biome consistently performed best, with a mean correlation of 0.93, an unbiased RMSE of 0.56 mm day -1, and a bias of -0.02 mm day -1 against in situ measurements of unstressed 15 evaporation. A Priestley and Taylor method, calibrated per biome, performed just slightly worse, yet substantially and consistently better than more complex Penman, Penman-Monteith-based or temperature-based approaches.We show that the poor performance of Penman-Monteith based approaches relates largely to the fact that the unstressed stomatal conductance was assumed constant. Further analysis showed that the biome-specific parameters required for the simple radiation-driven methods are relatively constant per biome. This makes this 20 simple radiation-driven method calibrated per biome a robust method that can be incorporated into models for improving our understanding of the impact of global warming on future global water use and demand, drought severity and ecosystem productivity.

show abstract

A comparison of models for estimating potential evapotranspiration for Florida land cover types

Cited by 133 publications

References 29 publications

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO ₂

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO ₂

Estimativa da evapotranspiração de referência a partir de dados meteorológicos limitados

Potential evaporation at eddy-covariance sites across the globe

Contact Info

Product

Resources

About

A comparison of models for estimating potential evapotranspiration for Florida land cover types

Cited by 133 publications

References 29 publications

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO 2

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO 2

Estimativa da evapotranspiração de referência a partir de dados meteorológicos limitados

Potential evaporation at eddy-covariance sites across the globe

Contact Info

Product

Resources

About

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO ₂

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO ₂