Uncertainty is one of the greatest challenges in the quantitative understanding of land-surface systems.This paper discusses the sources of uncertainty in land-surface systems and the possible means to reduce and cont...Uncertainty is one of the greatest challenges in the quantitative understanding of land-surface systems.This paper discusses the sources of uncertainty in land-surface systems and the possible means to reduce and control this uncertainty.From the perspective of model simulation,the primary source of uncertainty is the high heterogeneity of parameters,state variables,and near-surface atmospheric states.From the perspective of observation,we first utilize the concept of representativeness error to unify the errors caused by scale representativeness.The representativeness error also originates mainly from spatial heterogeneity.With the aim of controlling and reducing uncertainties,here we demonstrate the significance of integrating modeling and observations as they are complementary and propose to treat complex land-surface systems with a stochastic perspective.In addition,through the description of two modern methods of data assimilation,we delineate how data assimilation characterizes and controls uncertainties by maximally integrating modeling and observational information,thereby enhancing the predictability and observability of the system.We suggest that the next-generation modeling should depict the statistical distribution of dynamic systems and that the observations should capture spatial heterogeneity and quantify the representativeness error of observations.展开更多
Characterization of essential stability of minimum solutions for a class of optimization problems with boundedness and lower pseudocontinuity on a compact metric space is given. It shows that any optimization problem ...Characterization of essential stability of minimum solutions for a class of optimization problems with boundedness and lower pseudocontinuity on a compact metric space is given. It shows that any optimization problem considered here has one essential component(resp. one essential minimum solution) if and only if its minimum solution set is connected(resp. singleton) and that those optimization problems which have a unique minimum solution form a residual set(however, which need not to be dense).展开更多
基金supported by the National Natural Science Fundation of China for Distinguished Young Scientists(Grant No.40925004)the Chinese Academy of Sciences Action Plan for West Development Program Project(Grant No.KZCX2-XB3-15)the National Natural Science Foundation of China(Grant No.91125001)
文摘Uncertainty is one of the greatest challenges in the quantitative understanding of land-surface systems.This paper discusses the sources of uncertainty in land-surface systems and the possible means to reduce and control this uncertainty.From the perspective of model simulation,the primary source of uncertainty is the high heterogeneity of parameters,state variables,and near-surface atmospheric states.From the perspective of observation,we first utilize the concept of representativeness error to unify the errors caused by scale representativeness.The representativeness error also originates mainly from spatial heterogeneity.With the aim of controlling and reducing uncertainties,here we demonstrate the significance of integrating modeling and observations as they are complementary and propose to treat complex land-surface systems with a stochastic perspective.In addition,through the description of two modern methods of data assimilation,we delineate how data assimilation characterizes and controls uncertainties by maximally integrating modeling and observational information,thereby enhancing the predictability and observability of the system.We suggest that the next-generation modeling should depict the statistical distribution of dynamic systems and that the observations should capture spatial heterogeneity and quantify the representativeness error of observations.
基金supported by National Natural Science Foundation of China under Grants Nos.11161011and 11161015
文摘Characterization of essential stability of minimum solutions for a class of optimization problems with boundedness and lower pseudocontinuity on a compact metric space is given. It shows that any optimization problem considered here has one essential component(resp. one essential minimum solution) if and only if its minimum solution set is connected(resp. singleton) and that those optimization problems which have a unique minimum solution form a residual set(however, which need not to be dense).
