@Article{RaczkaHoDuFoAnBoLi:2021:ImCLBi,
               author = "Raczka, Brett and Hoar, Timothy J. and Duarte, Henrique Ferro and 
                         Fox, Andrew M. and Anderson, Jeffrey L. and Bowling, David R. and 
                         Lin, John C.",
          affiliation = "{University of Utah} and {National Center for Atmospheric 
                         Research} and {Instituto Nacional de Pesquisas Espaciais (INPE)} 
                         and {Joint Center for Satellite Data Assimilation} and {National 
                         Center for Atmospheric Research} and {University of Utah} and 
                         {University of Utah}",
                title = "Improving CLM5.0 Biomass and Carbon Exchange Across the Western 
                         United States Using a Data Assimilation System",
              journal = "Journal of Advances in Modeling Earth Systems",
                 year = "2021",
               volume = "13",
               number = "7",
                pages = "e2020MS002421",
                month = "July",
             keywords = "data assimilation, CLM, land-atmosphere carbon exchange, biomass 
                         stocks, DART, Western United States.",
             abstract = "The Western United States is dominated by natural lands that play 
                         a critical role for carbon balance, water quality, and timber 
                         reserves. This region is also particularly vulnerable to forest 
                         mortality from drought, insect attack, and wildfires, thus 
                         requiring constant monitoring to assess ecosystem health. Carbon 
                         monitoring techniques are challenged by the complex mountainous 
                         terrain, thus there is an opportunity for data assimilation 
                         systems that combine land surface models and satellite-derived 
                         observations to provide improved carbon monitoring. Here, we use 
                         the Data Assimilation Research Testbed to adjust the Community 
                         Land Model (CLM5.0) with remotely sensed observations of leaf area 
                         and above-ground biomass. The adjusted simulation significantly 
                         reduced the above-ground biomass and leaf area, leading to a 
                         reduction in both photosynthesis and respiration fluxes. The 
                         reduction in the carbon fluxes mostly offset, thus both the 
                         adjusted and free simulation projected a weak carbon sink to the 
                         land. This result differed from a separate observation-constrained 
                         model (FLUXCOM) that projected strong carbon uptake to the land. 
                         Simulation diagnostics suggested water limitation had an important 
                         influence upon the magnitude and spatial pattern of carbon uptake 
                         through photosynthesis. We recommend that additional observations 
                         important for water cycling (e.g., snow water equivalent, land 
                         surface temperature) be included to improve the veracity of the 
                         spatial pattern in carbon uptake. Furthermore, the assimilation 
                         system should be enhanced to maximize the number of the simulated 
                         state variables that are adjusted, especially those related to the 
                         recommended observed quantities including water cycling and soil 
                         carbon.",
                  doi = "10.1029/2020MS002421",
                  url = "http://dx.doi.org/10.1029/2020MS002421",
                 issn = "1942-2466",
             language = "en",
           targetfile = "2020MS002421.pdf",
        urlaccessdate = "11 jun. 2024"
}