Performance analysis of global HYCOM flow field using Argo profiles

Flow field data generated by ocean models are important for simulating ocean currents and circulation patterns,which are essential components in digital Earth construction.To evaluate the accuracy of model-simulatedflow felds,Array for Real-timeGeostrophic Oceanography(Argo)float observations can be considered benchmarks.In this study,a novel method for comparing Argo profiles with 3-dimensional trajectories obtained by simulating Argo floats in Hybrid Coordinate Ocean Model(HYCOM)-provided flow fields was proposed.Surface and subsurface trajectories were calculated,and their spatial matching characteristics were analyzed.The results demonstrated that(1)the HYCOM surface and subsurface flow felds generally conform to the basic characteristics and trends of ocean currents;(2)the HYCOM sea surface current field error pattern exhibits a symmetrical distribution centered on the equator in the Northern and Southern Hemispheres and increases with increasing latitude;and(3)the HYCOM subsurface flow field exhibits regional differences,with the largest differences in the Gulf Stream,North Atlantic Warm Current,and Westerly Wind Drift region.Through analysis of the disparities between HYCOM and Argo data,the effectiveness of using model simulation data can be enhanced,and the accuracy and dependability of ocean models can be improved.

地理综合研究方法的发展与思考

地理系统是一个复杂巨系统,地理综合研究是整体性认知与理解地理系统的重要途径.随着地理学的发展演进,地理综合成为新时期地理学创新与突破的根本任务;发展地理综合的理论方法,成为防止地理学空心化,建立地理学核心理论的重要途径.然而,传统地理综合方法多采用"先分后综"的思路,导致"易分难综",地理综合方法体系亟待进一步探索.本文总结了现有地理综合相关研究及方法,分析了阻碍地理综合研究方法发展的根结所在,提出了发展基于地理模态的地理综合研究方法新构想.地理模态作为地理系统规律性认知的描述形式与表达机制,是比地理要素与地理过程更高层次的抽象载体;以多层次地理模态的有机聚合、有序迭代形成地理系统的整体性、系统性认知,有望指导后期地理系统的综合研究与模型重构.基于地理模态的地理综合研究方法将试图打通片段地理认知到综合地理认知的双向通道,构建地理数据到地理规律再到综合地理认知的模型方法,推动地理综合研究在理论和方法上的协同演进,促进地理综合研究的发展.

Geographic modeling and simulation systems for geographic research in the new era: Some thoughts on their development and construction

Regionality,comprehensiveness,and complexity are regarded as the basic characteristics of geography.The exploration of their core connotations is an essential way to achieve breakthroughs in geography in the new era.This paper focuses on the important method in geographic research:Geographic modeling and simulation.First,we clarify the research requirements of the said three characteristics of geography and its potential to address geo-problems in the new era.Then,the supporting capabilities of the existing geographic modeling and simulation systems for geographic research are summarized from three perspectives:Model resources,modeling processes,and operational architecture.Finally,we discern avenues for future research of geographic modeling and simulation systems for the study of regional,comprehensive and complex characteristics of geography.Based on these analyses,we propose implementation architecture of geographic modeling and simulation systems and discuss the module composition and functional realization,which could provide theoretical and technical support for geographic modeling and simulation systems to better serve the development of geography in the new era.

Geographic scenario:a possible foundation for further development of virtual geographic environments

It has been two decades since virtual geographic environments(VGEs)were initially proposed.While relevant theories and technologies are evolving,data organization models have always been the foundation of VGE development,and they require further exploration.Based on the comprehensive consideration of the characteristics of VGEs,geographic scene is proposed to organize geographic information and data.We empirically find that geographic scene provides a suitable organization schema to support geo-visualization,geo-simulation,and geo-collaboration.To systematically investigate the concept and method of geographic scene,Geographic Scenario is proposed as the theory on developing geographic scene,and corresponding key issues of the Geographic Scenario are illustrated in this article.Prospects of the proposed method are discussed with the hope of informing future studies of VGEs.

A framework on task configuration and execution for distributed geographical simulation

Geographical simulation is a popular method in geographical and environmental research.Many models developed to address geographic and environmental issues are distributed worldwide.However,due to the lack of portals,these models are still difficult to invoke for geographical simulations in open web environments.This study designs and develops a framework to assemble service-oriented models from volunteers distributed worldwide for geographical simulations on the web.The framework consists of three layers(task layer,data exchange layer,and model execution layer)that establish a network of serviceoriented locally shared models and simulation tasks for user configurations.With the help of such a framework,users can configure simulation tasks and invoke suitable models shared worldwide for geographical simulations.This article provides an application of the distributed simulation of gross primary production(GPP)by the Biome-BioGeochemical Cycles(BGC)model in China.This application shows that the framework can be beneficial for model assembly from volunteers’computers and distributed simulation tasks that are run for geographical and environmental issues,which can be applied to Digital Earth initiatives.

Prototyping an open environment for sharing geographical analysis models on cloud computing platform

The sharing of geographical analysis models is of crucial importance for simulating geographic processes and phenomena in the current geographical information systems(e.g.Digital Earth),but there remain some issues that have not been completely resolved.The challenges include,eliminating model heterogeneity and searching for suitable infrastructures to support the open sharing and effective execution of models.Taking advantage of cloud computing,this article aims to address the above issues and develop an open environment for geographical analysis model sharing.On the basis of the analysis of the applicability of cloud computing,the architecture of the open environment is proposed.More importantly,key strategies designed for heterogeneous model description,model encapsulating as well as model deploying and transparent accessing in the cloud are discussed in detail to establish such an environment.Finally,the prototype environment is implemented,and experiments were conducted to verify the environment’s feasibility to support the sharing of geographical analysis models.

A new academic impact metric for evaluating geographic simulation models

Geographic simulation models can be used to explore and better understand the geographical environment. Recent advances in geographic and socio-environmental research have led to a dramatic increase in the number of models used for this purpose. Some model repositories provide opportunities for users to explore and apply models,but few provide a general evaluation method for assessing the applicability and recognition of models. In this study,an academic impact evaluation method for models is proposed. Five indices are designed based on their pertinence. The analytical hierarchy process is used to calculate the index weights,and the academic impacts of models are quantified with the weighted sum method. The time range is controlled to evaluate the life-term and annual academic impacts of the models. Some models that met the evaluation criteria from different domains are then evaluated. The results show that the academic impact of a model can be quantified with the proposed method,and the major research areas that models impact are identified.

A model-service deployment strategy for collaboratively sharing geo-analysis models in an open web environment

Geo-analysis models can be shared and reused via model-services to support more effective responses to risks and help to build a sustainable world.The deployment of model-services typically requires significant effort,primarily because of the complexity and disciplinary specifics of geo-analysis models.Various modelling participants engage in the collaborative modelling process:geo-analysis model resources are provided by model providers,computational resources are provided by computational resource providers,and the published model-services are accessed by model users.This paper primarily focuses on model-service deployment,with the basic goal of providing a collaboration-oriented method for modelling participants to conveniently work together and make full use of modelling and computational resources across an open web environment.For model resource providers,a model-deployment description method is studied to help build model-deployment packages;for computational resource providers,a computational resource description method is studied to help build model-service containers and connectors.An experimental system for sharing and reusing geo-analysis models is built to verify the capability and feasibility of the proposed methods.Through this strategy,modellers from dispersed regions can work together more easily,thus providing dynamic and reliable geospatial information for Future Earth studies.