HR: 14:50h
AN: C42B-05    [PDF]
TI: Modelling CLPX IOP3 Radiometric Data by Means of the Dense Media Theory: Preliminary Results for the LSOS Test Site
AU: * Tedesco, M
EM: tedesco@ifac.cnr.it
AF: NASA Cold Land Processes Working Group, Viale Italia, 199/b, Avellino, 83100 Italy
AU: Kim, E J
EM: ed.kim@nasa.gov
AF: Laboratory for Hydrospheric Processes, Goddard Space Flight Center, NASA, Code 975, Greenbelt, MD 20771 United States
AU: Cline, D
EM: cline@nohrsc.nws.gov
AF: National Operational Hydrologic Remote Sensing Center, National Weather Service, NOAA, 1735 Lake Drive West, Chanhassen, MN 55317 United States
AU: Graf, T
EM: tgraf@hydra.t.u-tokyo.ac.jp
AF: Department of Civil Engineering, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-8656 Japan
AU: Koike, T
EM: tkoike@hydra.t.u-tokyo.ac.jp
AF: Department of Civil Engineering, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-8656 Japan
AU: Armstrong, R
EM: rlax@kryos.colorado.edu
AF: National Snow and Ice Data Center, CIRES 449 UCB Univ. of Colorado, Boulder, CO 80309 United States
AU: Brodzik, M
EM: brodzik@zamboni.colorado.edu
AF: National Snow and Ice Data Center, CIRES 449 UCB Univ. of Colorado, Boulder, CO 80309 United States
AU: Hardy, J P
EM: janet.p.hardy@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory, USACE, 72 Lyme Road, Hanover, NH 03755 United States
AB: The capabilities of the Dense Media Radiative Transfer model using the Quasi Crystalline Approximation with Coherent Potential (QCA-CP) to reproduce measured radiometric data were tested using the University of Tokyo Ground Based Microwave Radiometer (GBMR-7) during the third Intensive Observation Period (IOP3) of the NASA Cold-land Processes Field Experiment (CLPX). The data were collected at the Local-Scale Observation Site (LSOS), a 0.8~ha study site consisting of two open meadows separated by trees. Intensive measurements were also made of snow depth and temperature, density, and grain size profiles. A DMRT model is needed to describe radiative transfer in a medium such as snow because the assumption of independent scattering used in classical radiative transfer theory (CRT) is not valid. Validation of the DMRT approach requires a relationship between measured snow grain size and the DMRT approximation of snow grain radius as spherical particles with a mean radius of the log-normal particle-size distribution. This relationship is very important for a better understanding of snow modelling and for practical applications. DMRT simulations were compared with observations of microwave brightnesses at 18.7, 36.5 and 89~GHz (V and H polarizations) collected on February~19-25, 2003. Observation angles ranged from 30\deg to 70\deg. Model inputs included measured snow parameters except mean grain size. The average snow temperature, fractional volume and depth were held constant, together with the ice and soil permittivities. The minimum and maximum measured mean grain sizes were used to test the capabilities of the DMRT to reproduce the brightnesses as upper and lower limits. The sensitivity to the largest and smallest measured grain size in the three classes of minimum, medium and maximum observed grain sizes was also investigated. DMRT particle sizes yielding a best-fit to the experimental data for each date were computed. Results show that the measured brightnesses fall within the range of simulated brightnesses using the smallest and largest measured grain size values. The DMRT best-fit radii are comparable to the average radii for the medium observed grain sizes.
DE: 1823 Frozen ground
DE: 1854 Precipitation (3354)
DE: 1863 Snow and ice (1827)
DE: 1894 Instruments and techniques
DE: 6969 Remote sensing
SC: Cryosphere [C]
MN: 2003 Fall Meeting