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United States Department of Agriculture

Agricultural Research Service

Research Project: Leveraging Remote Sensing, Land Surface Modeling and Ground-based Observations ... Variables within Heterogeneous Agricultural Landscapes

Location: Hydrology and Remote Sensing Laboratory

Title: Smap Validation Experiment 2012 (Smapvex12): Overview and Outlook

Authors
item Jackson, Thomas
item Mcnairn, H -
item Wiseman, G -
item Colliander, A -
item Berg, A -
item Magagi, R -
item Kim, S -
item Cosh, Michael
item Njoku, E -
item Belair, S -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 14, 2013
Publication Date: N/A

Technical Abstract: The Soil Moisture Active Passive (SMAP) mission will provide global soil moisture products that will facilitate new science and application areas, while extending those that have developed as a result of its predecessors. Validation of the suite of SMAP soil moisture and freeze/thaw products is a mission requirement. During the pre-launch phase of SMAP the major concerns related to validation are providing data for the development and evaluation of the SMAP algorithms and establishing the infrastructure to efficiently conduct the post-launch validation in a timely manner. Field campaigns are one of the methodologies that are used for these purposes. SMAP Algorithm Development Teams were asked to provide an assessment of what outstanding issues could be addressed with a field campaign. All of the soil moisture algorithms had two common requirements for a field campaign; an extended time series and diverse vegetation conditions. Data sets that supported the combined active passive algorithm were considered the top priority, which necessitated an aircraft instrument suite that could provide data to simulate the SMAP sensor system. This evaluation also indicated that it was critical that any campaign be conducted as soon as possible in order for the algorithm teams to effectively utilize the results. In response to the issues identified, a field campaign SMAP Validation Experiment 2012 (SMAPVEX12) was designed and executed. The primary objectives were as follows: 1) Collect an extended times series of concurrent active and passive microwave observations, 2) Capture a wide range of soil moisture conditions, 3) Observe a wide range of vegetation conditions that both include both types and growth stages, 4) Multiple resolution observations for scaling, 5) Find ways to better mitigate low-level RFI effects observed in North America, 6) Improve the parameterization of vegetation (and its water content), and 7) Contribute to establishing an in situ Cal/Val site for SMAP post-launch validation. A preliminary review indicated that these objectives could best be accomplished through collaboration with the Canadian Space Agency (CSA) as part of its partnership in the SMAP Project and broadening the experiment to incorporate additional objectives related to CSA goals. All participants collaborated in analyses; however, data collection leadership was divided with NASA having responsibility for aircraft and the Canadian team responsible for ground observations. Data processing is ongoing and more details and results will be available in the near future and will follow precedents from previous collborations. Both the weather conditions and instrument performance exceeded expectations resulting in SMAPVEX12 being very successful. A total of seventeen days of flights were conducted with supporting ground observations over 42 days (June 7-July 19, 2012). This simulated the temporal frequency expected from SMAP at mid-latitudes. Following the first flight, which had moderate soil moisture levels, there was a series of rain events that resulted in very wet conditions for several days. This wet period was followed by an extended drying of the soils that lasted over two weeks. The remainder of the campaign had mixed conditions. Many of the crops were near bare soil conditions at the outset of SMAPVEX12 and reached peak biomass/vegetation water content by its end. Winter wheat reached its peak biomass early in the campaign and then entered senescence. Both instruments/aircraft were able to collect data on every flight day. Very little data was lost due to RFI or instrument failure. Based upon the wide range of soil moisture and vegetation conditions that existed and that we were able to sample with both the ground-based and aircraft instruments, SMAPVEX12 was highly successful in achieving its objectives. Data processing is currently underway. Following a data quality and team evaluation period, all data will be archived at a public website. USDA is an equal opportunity employer.

Last Modified: 9/10/2014
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