DOI: 10.5194/hess-24-325-2020
论文题名: An ensemble square root filter for the joint assimilation of surface soil moisture and leaf area index within the Land Data Assimilation System LDAS-Monde: Application over the Euro-Mediterranean region
作者: Bonan B. ; Albergel C. ; Zheng Y. ; Lavinia Barbu A. ; Fairbairn D. ; Munier S. ; Calvet J.-C.
刊名: Hydrology and Earth System Sciences
ISSN: 1027-5606
出版年: 2020
卷: 24, 期: 1 起始页码: 325
结束页码: 347
语种: 英语
Scopus关键词: Kalman filters
; Petroleum reservoir evaluation
; Soil surveys
; Surface measurement
; Ensemble square root filter
; Gross primary production
; Land data assimilation systems
; Land surface models
; Mediterranean region
; Root mean square differences
; Strong correlation
; Surface soil moisture
; Soil moisture
; data assimilation
; evapotranspiration
; Kalman filter
; leaf area index
; net primary production
; satellite altimetry
; soil moisture
英文摘要: This paper introduces an ensemble square root filter (EnSRF) in the context of jointly assimilating observations of surface soil moisture (SSM) and the leaf area index (LAI) in the Land Data Assimilation System LDAS-Monde. By ingesting those satellite-derived products, LDAS-Monde constrains the Interaction between Soil, Biosphere and Atmosphere (ISBA) land surface model (LSM), coupled with the CNRM (Centre National de Recherches Météorologiques) version of the Total Runoff Integrating Pathways (CTRIP) model to improve the reanalysis of land surface variables (LSVs). To evaluate its ability to produce improved LSVs reanalyses, the EnSRF is compared with the simplified extended Kalman filter (SEKF), which has been well studied within the LDAS-Monde framework. The comparison is carried out over the Euro-Mediterranean region at a 0.25 spatial resolution between 2008 and 2017. Both data assimilation approaches provide a positive impact on SSM and LAI estimates with respect to the model alone, putting them closer to assimilated observations. The SEKF and the EnSRF have a similar behaviour for LAI showing performance levels that are influenced by the vegetation type. For SSM, EnSRF estimates tend to be closer to observations than SEKF values. The comparison between the two data assimilation approaches is also carried out on unobserved soil moisture in the other layers of soil. Unobserved control variables are updated in the EnSRF through covariances and correlations sampled from the ensemble linking them to observed control variables. In our context, a strong correlation between SSM and soil moisture in deeper soil layers is found, as expected, showing seasonal patterns that vary geographically. Moderate correlation and anti-correlations are also noticed between LAI and soil moisture, varying in space and time. Their absolute value, reaching their maximum in summer and their minimum in winter, tends to be larger for soil moisture in root-zone areas, showing that assimilating LAI can have an influence on soil moisture. Finally an independent evaluation of both assimilation approaches is conducted using satellite estimates of evapotranspiration (ET) and gross primary production (GPP) as well as measures of river discharges from gauging stations. The EnSRF shows a systematic albeit moderate improvement of root mean square differences (RMSDs) and correlations for ET and GPP products, but its main improvement is observed on river discharges with a high positive impact on Nash-Sutcliffe efficiency scores. Compared to the EnSRF, the SEKF displays a more contrasting performance. © 2020 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/162809
Appears in Collections: 气候变化与战略
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作者单位: Bonan, B., CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France; Albergel, C., CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France; Zheng, Y., CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France; Lavinia Barbu, A., CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France; Fairbairn, D., European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom; Munier, S., CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France; Calvet, J.-C., CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France
Recommended Citation:
Bonan B.,Albergel C.,Zheng Y.,et al. An ensemble square root filter for the joint assimilation of surface soil moisture and leaf area index within the Land Data Assimilation System LDAS-Monde: Application over the Euro-Mediterranean region[J]. Hydrology and Earth System Sciences,2020-01-01,24(1)