Dual-wavelength radar technique development for snow rate estimation

a case study from GCPEx

Gwo-Jong Huang, Viswanathan N. Bringi, Andrew J. Newman, Gyuwon Lee, Dmitri Moisseev, Branislav M. Notaros

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Quantitative precipitation estimation (QPE) of snowfall has generally been expressed in power-law form between equivalent radar reflectivity factor (Z(e)) and liquid equivalent snow rate (SR). It is known that there is large variability in the prefactor of the power law due to changes in particle size distribution (PSD), density, and fall velocity, whereas the variability of the exponent is considerably smaller. The dual-wavelength radar reflectivity ratio (DWR) technique can improve SR accuracy by estimating one of the PSD parameters (characteristic diameter), thus reducing the variability due to the prefactor. The two frequencies commonly used in dual-wavelength techniques are Ku- and Kabands. The basic idea of DWR is that the snow particle size-to-wavelength ratio is falls in the Rayleigh region at Ku-band but in the Mie region at Ka-band.

We propose a method for snow rate estimation by using NASA D3R radar DWR and Ka-band reflectivity observations collected during a long-duration synoptic snow event on 30-31 January 2012 during the GCPEx (GPM Cold-season Precipitation Experiment). Since the particle mass can be estimated using 2-D video disdrometer (2DVD) fall speed data and hydrodynamic theory, we simulate the DWR and compare it directly with D3R radar measurements. We also use the 2DVD-based mass to compute the 2DVD-based SR. Using three different mass estimation methods, we arrive at three respective sets of Z-SR and SR(Z(h), DWR) relationships. We then use these relationships with D3R measurements to compute radar-based SR. Finally, we validate our method by comparing the D3R radar-retrieved SR with accumulated SR directly measured by a well-shielded Pluvio gauge for the entire synoptic event.
Original languageEnglish
JournalAtmospheric Measurement Techniques
Volume12
Issue number2
Pages (from-to)1409-1427
Number of pages19
ISSN1867-1381
DOIs
Publication statusPublished - 1 Mar 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • ICE WATER-CONTENT
  • MICROPHYSICAL PROPERTIES
  • MEAN DENSITY
  • FALLING SNOW
  • SCATTERING
  • RETRIEVAL
  • FREQUENCY
  • SIZE
  • ORIENTATIONS
  • REFLECTIVITY
  • 1172 Environmental sciences

Cite this

Huang, Gwo-Jong ; Bringi, Viswanathan N. ; Newman, Andrew J. ; Lee, Gyuwon ; Moisseev, Dmitri ; Notaros, Branislav M. / Dual-wavelength radar technique development for snow rate estimation : a case study from GCPEx. In: Atmospheric Measurement Techniques. 2019 ; Vol. 12, No. 2. pp. 1409-1427.
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title = "Dual-wavelength radar technique development for snow rate estimation: a case study from GCPEx",
abstract = "Quantitative precipitation estimation (QPE) of snowfall has generally been expressed in power-law form between equivalent radar reflectivity factor (Z(e)) and liquid equivalent snow rate (SR). It is known that there is large variability in the prefactor of the power law due to changes in particle size distribution (PSD), density, and fall velocity, whereas the variability of the exponent is considerably smaller. The dual-wavelength radar reflectivity ratio (DWR) technique can improve SR accuracy by estimating one of the PSD parameters (characteristic diameter), thus reducing the variability due to the prefactor. The two frequencies commonly used in dual-wavelength techniques are Ku- and Kabands. The basic idea of DWR is that the snow particle size-to-wavelength ratio is falls in the Rayleigh region at Ku-band but in the Mie region at Ka-band.We propose a method for snow rate estimation by using NASA D3R radar DWR and Ka-band reflectivity observations collected during a long-duration synoptic snow event on 30-31 January 2012 during the GCPEx (GPM Cold-season Precipitation Experiment). Since the particle mass can be estimated using 2-D video disdrometer (2DVD) fall speed data and hydrodynamic theory, we simulate the DWR and compare it directly with D3R radar measurements. We also use the 2DVD-based mass to compute the 2DVD-based SR. Using three different mass estimation methods, we arrive at three respective sets of Z-SR and SR(Z(h), DWR) relationships. We then use these relationships with D3R measurements to compute radar-based SR. Finally, we validate our method by comparing the D3R radar-retrieved SR with accumulated SR directly measured by a well-shielded Pluvio gauge for the entire synoptic event.",
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author = "Gwo-Jong Huang and Bringi, {Viswanathan N.} and Newman, {Andrew J.} and Gyuwon Lee and Dmitri Moisseev and Notaros, {Branislav M.}",
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Dual-wavelength radar technique development for snow rate estimation : a case study from GCPEx. / Huang, Gwo-Jong; Bringi, Viswanathan N.; Newman, Andrew J.; Lee, Gyuwon; Moisseev, Dmitri; Notaros, Branislav M.

In: Atmospheric Measurement Techniques, Vol. 12, No. 2, 01.03.2019, p. 1409-1427.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Dual-wavelength radar technique development for snow rate estimation

T2 - a case study from GCPEx

AU - Huang, Gwo-Jong

AU - Bringi, Viswanathan N.

AU - Newman, Andrew J.

AU - Lee, Gyuwon

AU - Moisseev, Dmitri

AU - Notaros, Branislav M.

PY - 2019/3/1

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N2 - Quantitative precipitation estimation (QPE) of snowfall has generally been expressed in power-law form between equivalent radar reflectivity factor (Z(e)) and liquid equivalent snow rate (SR). It is known that there is large variability in the prefactor of the power law due to changes in particle size distribution (PSD), density, and fall velocity, whereas the variability of the exponent is considerably smaller. The dual-wavelength radar reflectivity ratio (DWR) technique can improve SR accuracy by estimating one of the PSD parameters (characteristic diameter), thus reducing the variability due to the prefactor. The two frequencies commonly used in dual-wavelength techniques are Ku- and Kabands. The basic idea of DWR is that the snow particle size-to-wavelength ratio is falls in the Rayleigh region at Ku-band but in the Mie region at Ka-band.We propose a method for snow rate estimation by using NASA D3R radar DWR and Ka-band reflectivity observations collected during a long-duration synoptic snow event on 30-31 January 2012 during the GCPEx (GPM Cold-season Precipitation Experiment). Since the particle mass can be estimated using 2-D video disdrometer (2DVD) fall speed data and hydrodynamic theory, we simulate the DWR and compare it directly with D3R radar measurements. We also use the 2DVD-based mass to compute the 2DVD-based SR. Using three different mass estimation methods, we arrive at three respective sets of Z-SR and SR(Z(h), DWR) relationships. We then use these relationships with D3R measurements to compute radar-based SR. Finally, we validate our method by comparing the D3R radar-retrieved SR with accumulated SR directly measured by a well-shielded Pluvio gauge for the entire synoptic event.

AB - Quantitative precipitation estimation (QPE) of snowfall has generally been expressed in power-law form between equivalent radar reflectivity factor (Z(e)) and liquid equivalent snow rate (SR). It is known that there is large variability in the prefactor of the power law due to changes in particle size distribution (PSD), density, and fall velocity, whereas the variability of the exponent is considerably smaller. The dual-wavelength radar reflectivity ratio (DWR) technique can improve SR accuracy by estimating one of the PSD parameters (characteristic diameter), thus reducing the variability due to the prefactor. The two frequencies commonly used in dual-wavelength techniques are Ku- and Kabands. The basic idea of DWR is that the snow particle size-to-wavelength ratio is falls in the Rayleigh region at Ku-band but in the Mie region at Ka-band.We propose a method for snow rate estimation by using NASA D3R radar DWR and Ka-band reflectivity observations collected during a long-duration synoptic snow event on 30-31 January 2012 during the GCPEx (GPM Cold-season Precipitation Experiment). Since the particle mass can be estimated using 2-D video disdrometer (2DVD) fall speed data and hydrodynamic theory, we simulate the DWR and compare it directly with D3R radar measurements. We also use the 2DVD-based mass to compute the 2DVD-based SR. Using three different mass estimation methods, we arrive at three respective sets of Z-SR and SR(Z(h), DWR) relationships. We then use these relationships with D3R measurements to compute radar-based SR. Finally, we validate our method by comparing the D3R radar-retrieved SR with accumulated SR directly measured by a well-shielded Pluvio gauge for the entire synoptic event.

KW - ICE WATER-CONTENT

KW - MICROPHYSICAL PROPERTIES

KW - MEAN DENSITY

KW - FALLING SNOW

KW - SCATTERING

KW - RETRIEVAL

KW - FREQUENCY

KW - SIZE

KW - ORIENTATIONS

KW - REFLECTIVITY

KW - 1172 Environmental sciences

U2 - 10.5194/amt-12-1409-2019

DO - 10.5194/amt-12-1409-2019

M3 - Article

VL - 12

SP - 1409

EP - 1427

JO - Atmospheric Measurement Techniques

JF - Atmospheric Measurement Techniques

SN - 1867-1381

IS - 2

ER -