• DOI:10.1029/2007JD008589
• Corpus ID: 17658602

A physical model to estimate snowfall over land using AMSU‐B observations

@article{Kim2008APM,
  title={A physical model to estimate snowfall over land using AMSU‐B observations},
  author={Min-Jeong Kim and Min-Jeong Kim and James A. Weinman and William S. Olson and William S. Olson and Dong-Eon Chang and Gail M. Skofronick-Jackson and James R. Wang},
  journal={Journal of Geophysical Research},
  year={2008},
  volume={113}
}

• Min-Jeong Kim, Min-Jeong Kim, +5 authors James R. Wang
• Published 16 May 2008
• Environmental Science
• Journal of Geophysical Research

[1] In this study, we present a physical model to retrieve snowfall rate over land using brightness temperature observations from NOAA's Advanced Microwave Sounder Unit-B (AMSU-B) at 89 GHz, 150 GHz, 183.3 ± 1 GHz, 183.3 ± 3 GHz, and 183.3 ± 7 GHz. The retrieval model is applied to the New England blizzard of 5 March 2001 which deposited about 75 cm of snow over much of Vermont, New Hampshire, and northern New York. In this physical model, prior retrieval assumptions about snowflake shape, particle size distributions, environmental conditions, and optimization methodology have been updated. Here, single scattering parameters for snow particles are calculated with the discrete-dipole approximation (DDA) method instead of assuming spherical shapes. Five different snow particle models are considered. Snow particle size distributions are assumed to vary with air temperature and to follow aircraft measurements described by previous studies. Brightness temperatures at AMSU-B frequencies for the New England blizzard are calculated using these DDA calculated single scattering parameters and particle size distributions. The vertical profiles of pressure, temperature, relative humidity and hydrometeors are provided by MM5 model simulations. These profiles are treated as the a priori database in the Bayesian retrieval algorithm. In algorithm applications to the blizzard data, calculated brightness temperatures associated with selected database profiles agree with AMSU-B observations to within about ±5 K at all five frequencies. Retrieved snowfall rates compare favorably with the near-concurrent National Weather Service (NWS) radar reflectivity measurements. The relationships between the NWS radar measured reflectivities Ze and retrieved snowfall rate R for a given snow particle model are derived by a histogram matching technique. All of these Ze-R relationships fall in the range of previously established Ze-R relationships for snowfall. This suggests that the current physical model developed in this study can reliably estimate the snowfall rate over land using the AMSU-B measured brightness temperatures.