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Evaluation of land surface models using ground-based point-scale measurements.

机译：使用基于地面的点尺度测量来评估陆地表面模型。

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摘要

Numerical models developed to simulate land-surface processes for different applications have to be validated against observations. This dissertation consists of two separate model validation and evaluation studies conducted over different regions. Each of these studies focuses on the dominant land-surface processes under those particular climatic conditions.; The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) Phase 2(d) experiment at Valdai, Russia looks into the models' abilities to correctly simulate land-surface hydrology in a cold region where snow and frozen soil related processes dominate. Building on previous work, I use newly available observations to investigate the thermal and hydrological impacts of frozen soil on soil temperature, soil moisture, and runoff, both in observations and model simulations. This study shows that the thermal impact of frozen soil on soil temperature is important and models can have correct soil temperature simulations in cold regions only if they explicitly account for soil water freezing or thawing. The hydrological impact of frozen soil is inconclusive in this study. No evidence suggests that the existence of frozen soil stops infiltration in this region. I also found that hysteresis in snow cover fraction, which is absent in all current parameterizations, might have quite an impact on snow simulations, in addition to snow physics.; The evaluation of the North American Land Data Assimilation System (NLDAS) over the Southern Great Plains focuses on validating the NLDAS forcing and evaluating the land surface models during the warm season. This study has validated the high quality of NLDAS retrospective forcing and revealed the differences in the partitioning of water and energy between the models and observations. The inter-model variation is quite striking given that models are driven by the same atmospheric forcing with the same land surface specifications. Several additional experiments conducted in this study imply that models can be improved and the difference between models can be reduced with careful calibrations and some fine-tuning. This also illustrates the value of the evaluation work in that evaluation and diagnosis of models provides insights on where the sources for errors are and in which direction models can be improved.
机译：必须针对观察结果验证为模拟不同应用的陆面过程而开发的数值模型。本文由两个分别在不同地区进行的模型验证和评估研究组成。这些研究中的每一个都着眼于那些特定气候条件下的主要地表过程。俄罗斯瓦尔代邦的地表参数化方案比较项目（PILPS）第二阶段（d）实验研究了该模型能够正确模拟在雪和冻土相关过程占主导的寒冷地区的地表水文学。在以前的工作的基础上，我使用新近获得的观测资料来研究观测和模型模拟中冻土对土壤温度，土壤湿度和径流的热力和水文影响。这项研究表明，冻土对土壤温度的热影响非常重要，只有在模型明确表明土壤水冻结或解冻的情况下，模型才能在寒冷地区具有正确的土壤温度模拟。在这项研究中，冻土的水文影响尚无定论。没有证据表明冻土的存在阻止了该地区的渗透。我还发现，除雪物理学之外，当前所有参数化中都没有的积雪分数的滞后可能会对积雪模拟产生很大影响。对大平原南部的北美土地数据同化系统（NLDAS）的评估重点在于验证NLDAS强迫和评估暖季期间的地表模型。这项研究验证了NLDAS追溯强迫的高质量，并揭示了模型和观测结果之间水和能量分配的差异。鉴于模型是由具有相同地面规格的相同大气强迫驱动的，因此模型间的差异非常惊人。在这项研究中进行的其他几个实验表明，通过仔细的校准和一些微调，可以改善模型，并减少模型之间的差异。这也说明了评估工作的价值，因为模型的评估和诊断可提供有关错误源在何处以及可以改进方向的见解。

著录项

  • 作者

    Luo, Lifeng.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Environmental Sciences.; Hydrology.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 143 p.
  • 总页数 143
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境科学基础理论;水文科学（水界物理学）;
  • 关键词

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