Title
Coupling a land-surface model with a crop growth model to improve et flux estimations in the Upper Ganges basin, India
Date Issued
28 October 2014
Access level
open access
Resource Type
journal article
Author(s)
Tsarouchi G.
Mijic A.
Imperial College London
Publisher(s)
Copernicus GmbH
Abstract
Land-Surface Models (LSMs) are tools that represent energy and water flux exchanges between land and the atmosphere. Although much progress has been made in adding detailed physical processes into these models, there is much room left for improved estimates of evapotranspiration fluxes, by including a more reasonable and accurate representation of crop dynamics. Recent studies suggest a strong land-surface-atmosphere coupling over India and since this is one of the most intensively cultivated areas in the world, the strong impact of crops on the evaporative flux cannot be neglected. In this study we dynamically couple the LSM JULES with the crop growth model InfoCrop. JULES in its current version (v3.4) does not simulate crop growth. Instead, it treats crops as natural grass, while using prescribed vegetation parameters. Such simplification might lead to modelling errors. Therefore we developed a coupled modelling scheme that simulates dynamically crop development and parametrized it for the two main crops of the study area, wheat and rice. This setup is used to examine the impact of inter-seasonal land cover changes in evapotranspiration fluxes of the Upper Ganges River basin (India). The sensitivity of JULES with regard to the dynamics of the vegetation cover is evaluated. Our results show that the model is sensitive to the changes introduced after coupling it with the crop model. Evapotranspiration fluxes, which are significantly different between the original and the coupled model, are giving an approximation of the magnitude of error to be expected in LSMs that do not include dynamic crop growth. For the wet season, in the original model, the monthly Mean Error ranges from 7.5 to 24.4 mm monthg-'1, depending on different precipitation forcing. For the same season, in the coupled model, the monthly Mean Error's range is reduced to 5.4-11.6 mm monthg'1. For the dry season, in the original model, the monthly Mean Error ranges from 10 to 17 mm monthg'1, depending on different precipitation forcing. For the same season, in the coupled model, the monthly Mean Error's range is reduced to 2.2-3.4 mm monthg'1. The new modelling scheme, by offering increased accuracy of evapotranspiration estimations, is an important step towards a better understanding of the two-way crops-atmosphere interactions.
Start page
4223
End page
4238
Volume
18
Issue
10
Language
English
OCDE Knowledge area
Oceanografía, Hidrología, Recursos hídricos Ciencia del suelo
Scopus EID
2-s2.0-84908577787
Source
Hydrology and Earth System Sciences
ISSN of the container
10275606
Sponsor(s)
Natural Environment Research Council NE/I022558/1 NERC
Sources of information: Directorio de Producción Científica Scopus