Active Layer Thickness and Moisture Content of Arctic Tundra From SVAT Models and Assimilated 1.4 or 6.9 GHz Brightness

来自 SVAT 模型和同化 1.4 或 6.9 GHz 亮度的北极苔原的活性层厚度和水分含量

• 批准号: 0240747
• 负责人: Anthony England
• 金额: $ 46.25万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-15 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0240747&HistoricalAwards=false
• 关键词: Active; Layer; Thickness; Moisture; Content

The long-term objective of this project is to enable near-daily satellite monitoring of thickness and water content of the active layer throughout the circumpolar Arctic. The PIs propose to test two hypotheses within the framework of Arctic-CHAMP: 1) Assimilation of plot-scale 1.4 or 6.9 GHz brightness in SVAT/Radiobrightness models will yield reliable histories of thickness and moisture content of the permafrost active layer; and 2) Assimilation of satellite-scale 1.4 or 6.9 GHz brightness in a distributed hydrology model having embedded SVAT/Radiobrightness linkages will yield meaningful spatially aggregated active layer histories. This assertion is supported by REBEX-3 data, which show plotscale 19 GHz brightness data (~3 m) to be nearly identical to SSM/I satellite-scale 19 GHz brightness data (~50 km) - a 4 order of magnitude span in spatial resolution. Soil-Vegetation-Atmosphere Transfer (SVAT) models depict energy and moisture transport and storage processes in soil, vegetation, and snow. SVAT moisture profiles have been made accurate to meter depths through assimilation of the moisture content of the top 5 cm of soil inferred from 1.4 GHz brightness. Although similar tests have not been made with 6.9 GHz data, these data have significant sensitivity to soil moisture and are now available from the new AMSR satellite instrument. For the assimilation approach with either frequency to work in the Arctic requires that tundra SVAT models linking active layer moisture content to microwave brightness be developed and calibrated. A NASA Global Water and Energy Cycle (GWEC) Program grant is permitting the PIs to build upon the success of their prairie Land Surface Process/Radiobrightness (LSP/R) model to develop and calibrate a diagnostic LSP/R model for arctic tundra. The GWEC project includes a six-week, plot-scale calibration experiment near Toolik Lake in 2004. The PIs propose to (1) extend that calibration experiment to the entire summer season, (2) create a parameterized inversion model to assimilate 1.4 or 6.9 GHz brightness data from the calibration experiment to test hypothesis 1, (3) embed the tundra LSP/R model and the parameterized inversion model in an existing hydrology model of the upper Kuparuk River watershed, (4) acquire AMSR satellite 6.9 GHz brightness data and create a season-long "nature run" of 1.4 GHz brightness data for an area of the Watershed equal to a satellite footprint (~2,500 km2), and (5) assimilate the satellite and synthesized nature run data to test hypothesis 2. The research is interdisciplinary between the Department of Atmospheric, Oceanic, and Space Sciences and the Department of Electrical Engineering and Computer Science at the University of Michigan. It offers scientists and engineers across these disciplines unique collaborative opportunities to introduce new technologies to arctic environmental science.

该项目的长期目标是能够对整个北极圈的活动层的厚度和含水量进行近乎每日的卫星监测。PI建议在Arctic-CHAMP的框架内检验两个假设：1）在SVAT/射电亮度模型中同化图尺度1.4或6.9 GHz亮度将产生可靠的冻土活动层厚度和含水量历史;和2）在具有嵌入式SVAT/辐射亮度的联系将产生有意义的空间聚集的活动层的历史。REBEX-3的数据支持这一说法，它表明绘图尺度19 GHz亮度数据（~3米）几乎与SSM/I卫星尺度19 GHz亮度数据（~50公里）相同-空间分辨率为4个数量级。土壤-植被-大气传输（SVAT）模型描述了能量和水分在土壤、植被和雪中的传输和储存过程。SVAT水分配置文件已准确到米深度通过同化的水分含量的顶部5厘米的土壤推断从1.4 GHz的亮度。虽然还没有用6.9 GHz的数据进行类似的测试，但这些数据对土壤湿度非常敏感，现在可以从新的AMSR卫星仪器中获得。对于同化方法，无论是在北极工作的频率，要求冻原SVAT模型联系活跃层水分含量微波亮度的开发和校准。美国宇航局全球水和能量循环（GWEC）计划拨款允许PI在其草原陆地表面过程/辐射亮度（LSP/R）模型的成功基础上开发和校准北极苔原的诊断LSP/R模型。GWEC项目包括2004年在图利克湖附近进行的为期六周的小块规模校准实验。PI建议（1）将校准实验扩展到整个夏季，（2）创建参数化反演模型，以同化校准实验中1.4或6.9 GHz亮度数据，以检验假设1，（3）将苔原LSP/R模型和参数化反演模型嵌入到Kuparuk河上游流域的现有水文模型中，（4）获取AMSR卫星6.9 GHz亮度数据，并为等于卫星覆盖区（约2，500 km 2）的分水岭区域创建一个1.4 GHz亮度数据的季节性“自然运行”，以及（5）同化卫星和合成自然运行数据以检验假设2。该研究是密歇根大学大气，海洋和空间科学系与电气工程和计算机科学系之间的跨学科研究。它为这些学科的科学家和工程师提供了独特的合作机会，将新技术引入北极环境科学。