Rain retrieval from dual-frequency radar Doppler spectra: validation and potential for a midlatitude precipitating case-study

In this study, we evaluated the performance of rain-retrieval algorithms for the Version 6 Global Precipitation Measurement Dual-frequency Precipitation Radar (GPM DPR) products, against disdrometer observations and improved their retrieval algorithms by using a revised shape parameter µ derived from long-term Particle Size Velocity (Parsivel) disdrometer observations in Jianghuai region from 2014 to 2018. To obtain the optimized shape parameter, raindrop size distribution (DSD) characteristics of summer and winter seasons over Jianghuai region are analyzed, in terms of six rain rate classes and two rain categories (convective and stratiform). The results suggest that the GPM DPR may have better performance for winter rain than summer rain over Jianghuai region with biases of 40% (80%) in winter (summer). The retrieval errors of rain category-based µ (3–5%) were proved to be the smallest in comparison with rain rate-based µ (11–13%) or a constant µ (20–22%) in rain-retrieval algorithms, with a possible application to rainfall estimations over Jianghuai region. Empirical Dm–Ze and Nw–Dm relationships were also derived preliminarily to improve the GPM rainfall estimates over Jianghuai region.

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Effect of Raindrop Size Distribution Variability in Dual-Frequency Radar Rain Retrieval Algorithms Assessed From Disdrometer Measurements

IEEE Geoscience and Remote Sensing Letters ◽

10.1109/lgrs.2005.862275 ◽

2006 ◽

Vol 3 (2) ◽

pp. 197-201 ◽

Cited By ~ 3

Author(s):

N.B. Adhikari ◽

T. Iguchi

Keyword(s):

Size Distribution ◽

Dual Frequency ◽

Raindrop Size Distribution ◽

Retrieval Algorithms ◽

Raindrop Size ◽

Rain Retrieval

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Rain Retrieval Performance of a Dual-Frequency Radar Technique with Differential Attenuation Constraint

2006 IEEE International Symposium on Geoscience and Remote Sensing ◽

10.1109/igarss.2006.14 ◽

2006 ◽

Author(s):

N. Adhikari ◽

T. Iguchi ◽

S. Seto ◽

N. Takahashi

Keyword(s):

Dual Frequency ◽

Retrieval Performance ◽

Rain Retrieval ◽

Radar Technique

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Application of the CSAMT Method to Pb–Zn Mineral Deposits: A Case Study in Jianshui, China

Minerals ◽

10.3390/min9120726 ◽

2019 ◽

Vol 9 (12) ◽

pp. 726 ◽

Cited By ~ 8

Author(s):

Zhenwei Guo ◽

Longyun Hu ◽

Chunming Liu ◽

Chuanghua Cao ◽

Jianxin Liu ◽

...

Keyword(s):

Mineral Exploration ◽

Signal Amplitude ◽

Ore Deposits ◽

Dual Frequency ◽

Ore Body ◽

Em Method ◽

Lead Zinc ◽

Subsurface Resistivity ◽

And Inversion

The electromagnetic (EM) method is commonly used in mineral exploration due to the method’s sensitivity to conductive targets. Controlled source audio-frequency magnetotellurics (CSAMT) is developed from magnetotelluric (MT) method with an artificial EM source to improve the signal amplitude. It has been used for mineral exploration for many years. In this study, we performed a case study of the CSAMT application for the Eagles-Nest lead–zinc (Pb–Zn) ore deposits in Jianshui, China. The Eagles-Nest deposit is located in southwest in China in forest-covered complex terrain, making it difficult to acquire the geophysical data. Based on the previous dual-frequency induced polarization (IP) results, we designed four profiles for the CSAMT data acquisition. After data processing and inversion, we mapped the subsurface resistivity distribution. From the CSAMT results, we inferred the location of the ore body, which was verified by the drilling wells. The Pb–Zn ore body was found at a depth between 373.70 m to 407.35 m in the well.

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Characteristics of DSD Bulk Parameters: Implication for Radar Rain Retrieval

Atmosphere ◽

10.3390/atmos11060670 ◽

2020 ◽

Vol 11 (6) ◽

pp. 670

Author(s):

Liang Liao ◽

Robert Meneghini ◽

Toshio Iguchi ◽

Ali Tokay

Keyword(s):

Shape Factor ◽

Droplet Size Distribution ◽

Measured Data ◽

Dual Frequency ◽

Model Data ◽

Field Campaigns ◽

Bulk Parameters ◽

Power Law Equation ◽

Rain Retrieval ◽

Two Parameter

With the use of 213,456 one-minute measured data of droplet-size distribution (DSD) of rain collected during several National Aeronautics and Space Administration (NASA)-sponsored field campaigns, the relationships between rainfall rate R, mass-weighted diameter Dm and normalized intercept parameter Nw of the gamma DSD are studied. It is found, based on the simulations of the gamma DSD model, that R, Dm and Nw are closely interrelated, and that the ratio of R to Nw is solely a function of Dm, independent of the shape factor μ of the gamma distribution. Furthermore, the model-produced ratio agrees well with those from the DSD data. When a power-law equation is applied to fit the model data, we have: R = aN w D m b , where a = 1.588 × 10 − 4 , b = 4.706 . Analysis of two-parameter relationships such as R–Dm, Nw–R and Nw–Dm reveals that R and Dm are moderately correlated while Nw and Dm are negatively correlated. Nw and R, however, are uncorrelated. The gamma DSD model also reveals that variation of R–Dm relation is caused primarily by Nw. For the application of the Ku- and Ka-band dual-frequency radar for the retrieval of the DSD bulk parameters as well as the specific radar attenuations, the study is carried out to relate the dual-frequency radar reflectivity factors to the DSD and attenuation parameters.

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