The influence of assimilating leaf area index in a land surface model on global water fluxes and storages
<p>Vegetation plays a fundamental role not only in the energy and carbon cycles but also in the global water balance by controlling surface evapotranspiration (ET). Thus, accurately estimating vegetation-related variables has the potential to improve our understanding and estimation of the dyn...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-07-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://hess.copernicus.org/articles/24/3775/2020/hess-24-3775-2020.pdf |
| Summary: | <p>Vegetation plays a fundamental role not only in the
energy and carbon cycles but also in the global water balance by
controlling surface evapotranspiration (ET). Thus, accurately estimating
vegetation-related variables has the potential to improve our understanding
and estimation of the dynamic interactions between the water, energy, and
carbon cycles. This study aims to assess the extent to which a land surface model
(LSM) can be optimized through the assimilation of leaf area index (LAI)
observations at the global scale. Two observing system simulation
experiments (OSSEs) are performed to evaluate the efficiency of assimilating
LAI into an LSM through an ensemble Kalman filter (EnKF) to estimate LAI,
ET, canopy-interception evaporation (CIE), canopy water storage (CWS),
surface soil moisture (SSM), and terrestrial water storage (TWS). Results
show that the LAI data assimilation framework not only effectively reduces
errors in LAI model simulations but also improves all the modeled water
flux and storage variables considered in this study (ET, CIE, CWS, SSM, and
TWS), even when the forcing precipitation is strongly positively biased
(extremely wet conditions). However, it tends to worsen some of the modeled
water-related variables (SSM and TWS) when the forcing precipitation is
affected by a dry bias. This is attributed to the fact that the amount of
water in the LSM is conservative, and the LAI assimilation introduces more
vegetation, which requires more water than what is available within the soil.</p> |
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| ISSN: | 1027-5606 1607-7938 |