We apply and compare three widely applicable methods for estimating ecosystem transpiration (T) from eddy covariance (EC) data across 251 FLUXNET sites globally. All three methods are based on the coupled water and carbon relationship, but they differ in assumptions and parameterizations. Intercomparison of the three daily T estimates shows high correlation among methods (R between .89 and .94), but a spread in magnitudes of T/ET (evapotranspiration) from 45% to 77%. When compared at six sites with concurrent EC and sap flow measurements, all three EC‐based T estimates show higher correlation to sap flow‐based T than EC‐based ET. The partitioning methods show expected tendencies of T/ET increasing with dryness (vapor pressure deficit and days since rain) and with leaf area index (LAI). Analysis of 140 sites with high‐quality estimates for at least two continuous years shows that T/ET variability was 1.6 times higher across sites than across years. Spatial variability of T/ET was primarily driven by vegetation and soil characteristics (e.g., crop or grass designation, minimum annual LAI, soil coarse fragment volume) rather than climatic variables such as mean/standard deviation of temperature or precipitation. Overall, T and T/ET patterns are plausible and qualitatively consistent among the different water flux partitioning methods implying a significant advance made for estimating and understanding T globally, while the magnitudes remain uncertain. Our results represent the first extensive EC data‐based estimates of ecosystem T permitting a data‐driven perspective on the role of plants’ water use for global water and carbon cycling in a changing climate.

Nelson, J.A.; Pérez-Priego, O.; Zhou, S.; Poyatos, R.; Zhang, Y.; Blanken, P.D.; Gimeno, T.E.; Wohlfahrt, G.; Desai, A.R.; Gioli, B.; Limousin, J.M.; Bonal, D.; Paul-Limoges, E.; Scott, R.L.; Varlagin, A.; Fuchs, K.; Montagnani, L.; Wolf, S.; Delpierre, N.; Berveiller, D.; Gharun, M.; Belelli Marchesini, L.; Gianelle, D.; Šigut, L.; Mammarella, I.; Siebicke, L.; Andrew, B.T.; Knohl, A.; Hörtnagl, L.; Magliulo, V.; Besnard, S.; Weber, U.; Carvalhais, N.; Migliavacca, M.; Reichstein, M.; Jung, M. (2020). Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites. GLOBAL CHANGE BIOLOGY, 26 (12): 6916-6930. doi: 10.1111/gcb.15314 handle: http://hdl.handle.net/10449/65078

Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites

Belelli Marchesini, L.;Gianelle, D.;
2020-01-01

Abstract

We apply and compare three widely applicable methods for estimating ecosystem transpiration (T) from eddy covariance (EC) data across 251 FLUXNET sites globally. All three methods are based on the coupled water and carbon relationship, but they differ in assumptions and parameterizations. Intercomparison of the three daily T estimates shows high correlation among methods (R between .89 and .94), but a spread in magnitudes of T/ET (evapotranspiration) from 45% to 77%. When compared at six sites with concurrent EC and sap flow measurements, all three EC‐based T estimates show higher correlation to sap flow‐based T than EC‐based ET. The partitioning methods show expected tendencies of T/ET increasing with dryness (vapor pressure deficit and days since rain) and with leaf area index (LAI). Analysis of 140 sites with high‐quality estimates for at least two continuous years shows that T/ET variability was 1.6 times higher across sites than across years. Spatial variability of T/ET was primarily driven by vegetation and soil characteristics (e.g., crop or grass designation, minimum annual LAI, soil coarse fragment volume) rather than climatic variables such as mean/standard deviation of temperature or precipitation. Overall, T and T/ET patterns are plausible and qualitatively consistent among the different water flux partitioning methods implying a significant advance made for estimating and understanding T globally, while the magnitudes remain uncertain. Our results represent the first extensive EC data‐based estimates of ecosystem T permitting a data‐driven perspective on the role of plants’ water use for global water and carbon cycling in a changing climate.
Ecohydrology
Eddy covariance
Evaporation
Evapotranspiration
FLUXNET
Transpiration
Settore BIO/07 - ECOLOGIA
2020
Nelson, J.A.; Pérez-Priego, O.; Zhou, S.; Poyatos, R.; Zhang, Y.; Blanken, P.D.; Gimeno, T.E.; Wohlfahrt, G.; Desai, A.R.; Gioli, B.; Limousin, J.M.; Bonal, D.; Paul-Limoges, E.; Scott, R.L.; Varlagin, A.; Fuchs, K.; Montagnani, L.; Wolf, S.; Delpierre, N.; Berveiller, D.; Gharun, M.; Belelli Marchesini, L.; Gianelle, D.; Šigut, L.; Mammarella, I.; Siebicke, L.; Andrew, B.T.; Knohl, A.; Hörtnagl, L.; Magliulo, V.; Besnard, S.; Weber, U.; Carvalhais, N.; Migliavacca, M.; Reichstein, M.; Jung, M. (2020). Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites. GLOBAL CHANGE BIOLOGY, 26 (12): 6916-6930. doi: 10.1111/gcb.15314 handle: http://hdl.handle.net/10449/65078
File in questo prodotto:
File Dimensione Formato  
gcb.15314.pdf

accesso aperto

Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Creative commons
Dimensione 2.76 MB
Formato Adobe PDF
2.76 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10449/65078
Citazioni
  • ???jsp.display-item.citation.pmc??? 5
  • Scopus 102
  • ???jsp.display-item.citation.isi??? 99
social impact