Soil Moisture Assimilation Improves Terrestrial Biosphere Model GPP Responses to Sub-Annual Drought at Continental Scale
(2023) In Remote Sensing 15(3).- Abstract
Due to the substantial gross exchange fluxes with the atmosphere, the terrestrial carbon cycle plays a significant role in the global carbon budget. Drought commonly affects terrestrial carbon absorption negatively. Terrestrial biosphere models exhibit significant uncertainties in capturing the carbon flux response to drought, which have an impact on estimates of the global carbon budget. Through plant physiological processes, soil moisture tightly regulates the carbon cycle in the environment. Therefore, accurate observations of soil moisture may enhance the modeling of carbon fluxes in a model–data fusion framework. We employ the Carbon Cycle Data Assimilation System (CCDAS) to assimilate 36-year satellite-derived surface soil... (More)
Due to the substantial gross exchange fluxes with the atmosphere, the terrestrial carbon cycle plays a significant role in the global carbon budget. Drought commonly affects terrestrial carbon absorption negatively. Terrestrial biosphere models exhibit significant uncertainties in capturing the carbon flux response to drought, which have an impact on estimates of the global carbon budget. Through plant physiological processes, soil moisture tightly regulates the carbon cycle in the environment. Therefore, accurate observations of soil moisture may enhance the modeling of carbon fluxes in a model–data fusion framework. We employ the Carbon Cycle Data Assimilation System (CCDAS) to assimilate 36-year satellite-derived surface soil moisture observations in combination with flask samples of atmospheric CO2 concentrations. We find that, compared to the default model, the performance of optimized net ecosystem productivity (NEP) and gross primary productivity (GPP) has increased with the RMSEs reduced by 1.62 gC/m2/month and 10.84 gC/m2/month, which indicates the added value of the ESA-CCI soil moisture observations as a constraint on the terrestrial carbon cycle. Additionally, the combination of soil moisture and CO2 concentration in this study improves the representation of inter-annual variability of terrestrial carbon fluxes as well as the atmospheric CO2 growth rate. We thereby investigate the ability of the optimized GPP in responding to drought by comparing continentally aggregated GPP with the drought index. The assimilation of surface soil moisture has been shown to efficiently capture the influences of the sub-annual (≤9 months drought durations) and large-scale (e.g., regional to continental scales) droughts on GPP. This study highlights the significant potential of satellite soil moisture for constraining inter-annual models of the terrestrial biosphere’s carbon cycle and for illustrating how GPP responds to drought at a continental scale.
(Less)
- author
- Xing, Xiuli ; Wu, Mousong LU ; Scholze, Marko LU ; Kaminski, Thomas ; Vossbeck, Michael ; Lu, Zhengyao LU ; Wang, Songhan ; He, Wei ; Ju, Weimin and Jiang, Fei
- organization
- publishing date
- 2023
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- carbon cycle data assimilation system, drought, ESA-CCI soil moisture, gross primary productivity
- in
- Remote Sensing
- volume
- 15
- issue
- 3
- article number
- 676
- publisher
- MDPI AG
- external identifiers
-
- scopus:85147925365
- ISSN
- 2072-4292
- DOI
- 10.3390/rs15030676
- language
- English
- LU publication?
- yes
- id
- 1c818c14-ebf8-427e-8b9e-376d4e6319b0
- date added to LUP
- 2023-03-06 12:51:45
- date last changed
- 2023-09-08 21:12:31
@article{1c818c14-ebf8-427e-8b9e-376d4e6319b0,
abstract = {{<p>Due to the substantial gross exchange fluxes with the atmosphere, the terrestrial carbon cycle plays a significant role in the global carbon budget. Drought commonly affects terrestrial carbon absorption negatively. Terrestrial biosphere models exhibit significant uncertainties in capturing the carbon flux response to drought, which have an impact on estimates of the global carbon budget. Through plant physiological processes, soil moisture tightly regulates the carbon cycle in the environment. Therefore, accurate observations of soil moisture may enhance the modeling of carbon fluxes in a model–data fusion framework. We employ the Carbon Cycle Data Assimilation System (CCDAS) to assimilate 36-year satellite-derived surface soil moisture observations in combination with flask samples of atmospheric CO<sub>2</sub> concentrations. We find that, compared to the default model, the performance of optimized net ecosystem productivity (NEP) and gross primary productivity (GPP) has increased with the RMSEs reduced by 1.62 gC/m<sup>2</sup>/month and 10.84 gC/m<sup>2</sup>/month, which indicates the added value of the ESA-CCI soil moisture observations as a constraint on the terrestrial carbon cycle. Additionally, the combination of soil moisture and CO<sub>2</sub> concentration in this study improves the representation of inter-annual variability of terrestrial carbon fluxes as well as the atmospheric CO<sub>2</sub> growth rate. We thereby investigate the ability of the optimized GPP in responding to drought by comparing continentally aggregated GPP with the drought index. The assimilation of surface soil moisture has been shown to efficiently capture the influences of the sub-annual (≤9 months drought durations) and large-scale (e.g., regional to continental scales) droughts on GPP. This study highlights the significant potential of satellite soil moisture for constraining inter-annual models of the terrestrial biosphere’s carbon cycle and for illustrating how GPP responds to drought at a continental scale.</p>}},
author = {{Xing, Xiuli and Wu, Mousong and Scholze, Marko and Kaminski, Thomas and Vossbeck, Michael and Lu, Zhengyao and Wang, Songhan and He, Wei and Ju, Weimin and Jiang, Fei}},
issn = {{2072-4292}},
keywords = {{carbon cycle data assimilation system; drought; ESA-CCI soil moisture; gross primary productivity}},
language = {{eng}},
number = {{3}},
publisher = {{MDPI AG}},
series = {{Remote Sensing}},
title = {{Soil Moisture Assimilation Improves Terrestrial Biosphere Model GPP Responses to Sub-Annual Drought at Continental Scale}},
url = {{http://dx.doi.org/10.3390/rs15030676}},
doi = {{10.3390/rs15030676}},
volume = {{15}},
year = {{2023}},
}