Collaborative Research: Estimating Regional Forest Evapotranspiration and Photosynthesis with a Satellite Derived Vegetation Index and Surface Temperature

合作研究：利用卫星导出的植被指数和地表温度估算区域森林蒸散量和光合作用

• 批准号: 8817965
• 负责人: Steven Running
• 金额: $ 25.28万
• 依托单位: University of Montana
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-01-15 至 1992-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8817965&HistoricalAwards=false
• 关键词: Collaborative; Research; Estimating; Regional; Forest

Current maps of global vegetation have been produced by the Normalized Difference Vegetation Index (NDVI) from the AVHRR satellite sensor. These maps have been related to absorbed solar radiation or surface leaf area index, but the NDVI has only been related theoretically to evapotranspiration and photosynthesis processes for vegetation and then only under optimal conditions of water and temperature, constraints that severely limit real world applications. The project will utilize a simple evapotranspiration and photosynthesis model for forests driven entirely by AVHRR data that is sensitive to sub-optimal water and temperature conditions. The investigators will (1) relate the seasonal trend of weekly composite NDVI to vegetation phenology and temperature limits, (2) test a satellite-derived surface resistance factor which is related to canopy diffusion resistance and (3) define physiologically based energy to mass conversion factors for carbon and water. These NDVI driven models will then be evaluated against a more complex ecosystem process model. The resulting simple, satellite-driven forest canopy models should allow a vastly improved computation of surface water and carbon exchange rates by global forests and improve accuracy of global carbon and hydrologic budgets. Output from the project should be useful in understanding the regional-to-global dynamics of water, CO2 and climate with regard to the "greenhouse effect" as well as possibly providing better, more rapid means of estimating forest production on large scales. The investigators are quite well qualified. Institutional accommodations and support for both collaborators is excellent. The Ecosystem Studies Program recommends support for this three- year collaborative effort.

目前的全球植被图是由 AVHRR的归一化植被指数 卫星传感器 这些地图与吸收的太阳能有关 辐射或表面叶面积指数，但植被指数只 理论上与蒸散和光合作用有关 只有在最佳条件下， 水和温度的限制，严重限制了真实的 世界应用。 该项目将利用一个简单的 森林蒸散和光合作用模型 完全由AVHRR数据，是敏感的次优水， 温度条件。 调查人员将（1） 周合成NDVI对植被物候的季节变化趋势 和温度限制，（2）测试卫星导出的表面 与冠层扩散阻力有关的阻力因子 以及（3）定义基于生理学的能量质量转换 碳和水的因素。 这些NDVI驱动模型将 根据更复杂的生态系统过程模型进行评估。 的 由此产生的简单的卫星驱动的森林冠层模型应该 大大改进了地表水和碳的计算 全球森林的汇率，并提高全球 碳和水文预算。 项目的产出应该有助于理解 水、二氧化碳和气候的区域至全球动态， “温室效应”以及可能提供更好的， 更快速的大规模估算森林产量的手段。 调查人员都很合格。 体制 住宿和支持两个合作者是非常好的。 生态系统研究计划建议支持这三个- 年的合作努力。