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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - How does the Spatial Scale Mismatch Between in Situ and Smos Soil Moisture Evolve Through Timescales?
摘要： The SMOS (Soil Moisture and Ocean Salinity) mission, together with other passive microwave based missions (AMSR, SMAP), provides soil moisture estimates at resolutions ranging from 30 to 55 km. These estimates are validated by direct comparison to in situ measurements that typically measure over an area of a few centimeters. There exist a spatial scale mismatch between the satellite (large support) and the in situ measurements (point support), which contributes to the differences observed. Their magnitude depends on the spatial representativeness of the in situ measurements, which varies in time and with the selected location. This communication will show how the spatial scale mismatch evolves through timescales. It is characterized by using modeled, in situ and satellite soil moisture time series. Timescales, from 0.5 to 128 days, are obtained using wavelet transforms and the spatial representativeness is assessed with a new approach that uses wavelet-based correlations (WCor).
关键词： time scales,satellite validation,wavelet decomposition,soil moisture,spatial representativeness,spatial scales
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - SIM Time Scale: 10 Years of Operation
摘要： The Inter-American Metrology System (SIM) is one of the world′s five major Regional Metrology Organizations (RMO′s). Starting in 2005, the SIM Time and Frequency Metrology Working Group (SIM TFWG) developed a time and frequency comparison network for the Americas (SIMTN). Currently 23 NMIs from SIM region participate on the SIMTN. Since 2008 the SIM TFWG is producing a time scale called SIM Time Scale (SIMT). SIMT is an averaged time scale computed in near real-time (every hour) from time difference data that the SIMTN produces and publishes every 10 minutes. In this paper, a SIMT evaluation based on data from August 2016 to January 2018 is presented.
关键词： international comparison,atomic clocks,Time Scales
更新于2025-09-10 09:29:36