Reexamination and further development of two‐stream canopy radiative transfer models for global land modeling. (22nd January 2017)

• Record Type: Journal Article
• Authors: Yuan, Hua; Dai, Yongjiu; Dickinson, Robert E.; Pinty, Bernard; Shangguan, Wei; Zhang, Shupeng; Wang, Lili; Zhu, Siguang
• Is Part Of: Journal of advances in modeling earth systems. Volume 9:Number 1(2017)
• Page Start: 113
• Page End: 129
• Publication Date: 2017-01-22
• Subjects: vegetation canopy radiative transfer -- two‐stream approximation -- the Community Land Model; Geological modeling -- Periodicals; Climatology -- Periodicals; Geochemical modeling -- Periodicals; 551.5011
• DOI: 10.1002/2016MS000773
• Languages: English
• ISSNs: 1942-2466

Abstract

Abstract: Four representative two‐stream canopy radiative transfer models were examined and intercompared using the same configuration. Based on the comparison results, two modifications were introduced to the widely used Dickinson‐Sellers model and then incorporated into the Community Land Model (CLM4.5). The modified model was tested against Monte‐Carlo simulations and produced significant improvements in the simulated canopy transmittance and albedo values. In direct comparison with MODIS albedo data, the modified model shows good performance over most snow/ice‐free vegetated areas, especially for regions that are covered by dense canopy. The modified model shows seasonally dependent behavior mainly in the near‐infrared band. Thus, the improvements are not present in all seasons. Large biases are still noticeable in sparsely vegetated areas, in particular for the snow/ice covered regions, that is possibly related to the model, the land surface input data, or even the observations themselves. Further studies focusing on the impact of the seasonal changes in leaf optical properties, the parameterizations for snow/ice covered regions and the case of sparsely vegetated areas, are recommended. Key Points: Parameterizations of four representative two‐stream canopy radiative transfer models have been compared Two major improvements made to the two‐stream canopy radiative transfer model in the Community Land Model (CLM4.5) The new model shows significant improvements in comparison with both Monte‐Carlo simulations and MODIS albedo