HR: 0800h
AN: C21B-0459    [Abstracts]
TI: Prototyping and Testing a Wireless Sensor Network to Retrieve SWE at High Spatial Resolution
AU: * Kang, D
EM: dk43@duke.edu
AF: Duke University, Environmental Physics Lab. Dept. of Civil and Environmental Engineering, Durham, NC 27708, United States
AU: Barros, A P
EM: ana.barros@duke.edu
AF: Duke University, Environmental Physics Lab. Dept. of Civil and Environmental Engineering, Durham, NC 27708, United States
AB: A critical challenge in snow research from space is the ability to obtain measurements at the spatial and temporal resolution to characterize the statistical structure of the space-time variability of the physical properties of the snowpack within an area consistent with the pixel resolution in snow hydrology models or that expected from a future NASA mission dedicated to cold region processes. That is, observations of relevant snow dielectric properties are necessary at high spatial and temporal resolution during the accumulation and melt seasons. We present a new wireless sensor network prototype consisting of multiple antennas and buried low-power, multi- channel transmitters operating in L-band that communicate to a central pod equipped with a Vector Signal Analyzer (VSA) that receives, processes and manages the data. Only commercial off-the-shelf hard-ware parts were used to build the sensors. Because the sensors are very low cost and run autonomously, one envisions that self-organizing networks of large numbers of such sensors might be distributed over very large areas, therefore proving much needed data sets for scaling studies. The measurement strategy consists of placing the transmitters the land surface in the beginning of the snow season which are then run autonomously till the end of the spring and waken at pre-determined time-intervals to emit radio frequency signals and thus sample the snowpack. Along with the sensors, an important component of this work entails the development of an estimation algorithm to estimate snow dielectric properties, snow density, and volume fraction of snow (VF) from the time-of-travel, amplitude and phase modification of the multi-channel RF signals as they propagate through the snow-pack. Here, we present results from full system testing and evaluation of the sensors that were conducted at Duke University using ¢®”Ęsynthetic¢®”¾ limited-area snowpacks (0.5 by 0.5 m2 and 1 by 2 m2) constructed of various combinations of foam layers of different porosities to simulate heterogeneous distributions of water. The existing sensors are currently being primed for field deployment. Discussion is also presented regarding further technology development including power usage, networking, and distribution and operations in remote regions.
DE: 0736 Snow (1827, 1863)
DE: 2487 Wave propagation (0689, 3285, 4275, 4455, 6934)
DE: 4894 Instruments, sensors, and techniques
DE: 5460 Physical properties of materials
DE: 6964 Radio wave propagation
SC: Cryosphere [C]
MN: 2007 Fall Meeting