Mike Schwank

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The scope of this study is to establish the parameters of the L-band (1.4 GHz) Microwave Emission of the Biosphere model (L-MEB) for grass covers, and to assess surface soil moisture retrievals in areas covered by grass. L-MEB parameters are key ancillary information for the Soil Moisture and Ocean Salinity mission (SMOS) retrieval algorithm that produces(More)
A field experiment with an L-band radiometer at 1.4 GHz was performed from May–July 2004 at an experimental site near Zurich, Switzerland. Before the experiment started, clover grass was seeded. Thermal infrared, in situ temperature, and time-domain reflectometer (TDR) measurements were taken simultaneously with hourly radiometer measurements. This setup(More)
We report on field-measured microwave emission in a period of frost penetration into a grassland soil. The measurements were recorded with a high temporal resolution using an L-band radiometer mounted on a 7-m high tower. The observation period (December 2002 to March 2003) included two cycles of soil freezing and thawing with maximum frost depth of 25 cm.(More)
L-band (1-2 GHz) microwave radiometry is a remote sensing technique that can be used to monitor soil moisture, and is deployed in the Soil Moisture and Ocean Salinity (SMOS) Mission of the European Space Agency (ESA). Performing ground-based radiometer campaigns before launch, during the commissioning phase and during the operative SMOS mission is important(More)
The microwave Forest Soil Moisture Experiment (FOSMEX) was performed at a deciduous forest site at the Research Centre Jülich (Germany). An Land an X-band radiometer were mounted 100 m above ground and directed to the canopy. The measurements consist of dualand single-polarized Land X-band data and simultaneously recorded ground moisture, temperature, and(More)
The crown vegetation of a deciduous forest is known to be semitransparent at low microwave frequencies, and leaf litter covering the forest soil has been recognized to have a significant impact on ground emission. The proposed approach for modeling the L-band radiative transfer through leaf litter consists of an isotropic effective medium approach for the(More)
Accurate estimates of surface soil moisture are essential in many research fields, including agriculture, hydrology, and meteorology. The objective of this study was to evaluate two remote-sensing methods for mapping the soil moisture of a bare soil, namely, L-band radiometry using brightness temperature and ground-penetrating radar (GPR) using surface(More)
3 Maciej Miernecki, Jean-Pierre Wigneron, Ernesto Lopez-Baeza,Yann Kerr, Richard De Jeu, 4 Gabrielle J. M. De Lannoy, Tom J. Jackson, Peggy E. O'Neill, Mike Schwank, Roberto Fernandez 5 Moran, Simone Bircher, Heather Laurence, Arnaud Mialon, Ahmad Al Bitar, Philippe Richaume 6 7 a University of Hamburg, Center for Marine and Atmospheric Sciences (ZMAW),(More)
Ring-capacitor sensors are used widely for real-time estimation of volumetric soil water content u from measured resonant frequency fr, which is directly affected by the bulk soil permittivity e. However, the relationship fr(e) requires improved quantification. We conducted laboratory experiments to characterize the response of the Sentek EnviroSMART sensor(More)
Recent studies of passive L-band observations over forests have shown that the average canopy transmissivity in temperate coniferous and deciduous forests is on the order of 0.4–0.5. Although the canopy would therefore be expected to transmit a reasonable amount of ground emission, the total emission observed above the canopy shows very little variation(More)