Effects of Nonuniform Beam Filling on Rainfall Retrieval for the TRMM Precipitation Radar

Durden, Stephen L.; Haddad, Ziad S.; Kitiyakara, A.; Li, F. K.

doi:10.1175/1520-0426(1998)015<0635:eonbfo>2.0.co;2

Cited by 63 publications

(57 citation statements)

References 22 publications

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“…However, the nonlinear nature of the radar attenuation equation and the power-law relations among specific attenuation (k), radar reflectivity factor (Ze), and precipitation rate (R) are known to induce biases in PIA and the retrieved precipitation rate in the presence of horizontal nonuniformity within the PR field-of-view (FOV), namely the nonuniform beam filling (NUBF) effect (Kozu and Iguchi 1999). High spatial resolution observations from an airborne TRMM PR prototype confirm the presence of the NUBF effect in TRMM PR-scale FOVs and its effects on retrieval algorithms (Durden et al 1998). In addition, the airborne radar data reveal evidence of vertical decorrelation in the radar reflectivity fields.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Nonuniform Beam Filling Effects by Vertical Decorrelation: Theory and Simulations

Short

Nakagawa

Iguchi

2013

Journal of the Meteorological Society of Japan

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Algorithms for estimating precipitation rates from spaceborne radar observations of apparent radar reflectivity depend on attenuation correction procedures. The algorithm suite for the Ku-band precipitation radar aboard the Tropical Rainfall Measuring Mission satellite is one such example. The well-known problem of nonuniform beam filling is a source of error in the estimates, especially in regions where intense deep convection occurs. The error is caused by unresolved horizontal variability in precipitation characteristics such as specific attenuation, rain rate, and effective reflectivity factor. This paper proposes the use of vertical decorrelation for correcting the nonuniform beam filling error developed under the assumption of a perfect vertical correlation. Empirical tests conducted using ground-based radar observations in the current simulation study show that decorrelation effects are evident in tilted convective cells. However, the problem of obtaining reasonable estimates of a governing parameter from the satellite data remains unresolved.

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Section: Introductionmentioning

confidence: 99%

Reduction of Nonuniform Beam Filling Effects by Vertical Decorrelation: Theory and Simulations

Short

Nakagawa

Iguchi

2013

Journal of the Meteorological Society of Japan

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“…An example of such a radar is the Precipitation Radar (PR) aboard the TRMM satellite. It has provided unprecedented precipitation measurements over land (Iguchi et al, 2000), but it may underestimate the intensity of shallow precipitation or that from rain cells smaller than 4 km (Durden et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land

Marzano

Mori

Chini

et al. 2011

Hydrol. Earth Syst. Sci.

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Abstract. X-band Synthetic Aperture Radars (X-SARs), able to image the Earth's surface at metric resolution, may provide a unique opportunity to measure rainfall over land with spatial resolution of about few hundred meters, due to the atmospheric moving-target degradation effects. This capability has become very appealing due to the recent launch of several X-SAR satellites, even though several remote sensing issues are still open. This work is devoted to: (i) explore the potential of X-band high-resolution detection and retrieval of rainfall fields from space using X-SAR signal backscattering amplitude and interferometric phase; (ii) evaluate the effects of spatial resolution degradation by precipitation and inhomogeneous beam filling when comparing to other satellite-based sensors. Our X-SAR analysis of precipitation effects has been carried out using both a TerraSAR-X (TSX) case study of Hurricane "Gustav" in 2008 over Mississippi (USA) and a COSMO-SkyMed (CSK) X-SAR case study of orographic rainfall over Central Italy in 2009. For the TSX case study the near-surface rain rate has been retrieved from the normalized radar cross section by means of a modified regression empirical algorithm (MREA). A relatively simple method to account for the geometric effect of X-SAR observation on estimated rainfall rate and firstorder volumetric effects has been developed and applied. The TSX-retrieved rain fields have been compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (AL, USA). The rainfall detection capability of X-SAR has been tested on the CSK case study using the Correspondence to: F. S. Marzano (marzano@die.uniroma1.it) repeat-pass coherence response and qualitatively comparing its signature with ground-based Mt. Midia C-band radar in central Italy. A numerical simulator to represent the effect of the spatial resolution and the antenna pattern of TRMM satellite Precipitation Radar (PR) and Microwave Imager (TMI), using high-resolution TSX-retrieved rain images, has been also set up in order to evaluate the rainfall beam filling phenomenon. As expected, the spatial average can modify the statistics of the high-resolution precipitation fields, strongly reducing its dynamics in a way non-linearly dependent on the rain rate local average value.

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“…The Precipitation Radar (PR) aboard the Tropical Rainfall Measurement Mission (TRMM) satellite has provided unique precipitation measurements as demonstrated by Kummerow et al (2000), but even the 4 km horizontal resolution, and the Signal/Noise Ratio (SNR) floor of the PR may inhibit the measurement of compact rain cells, Durden et al (1998).…”

Section: Introductionmentioning

confidence: 99%

Rainfall observation from X-band, space-borne, synthetic aperture radar

Weinman

Marzano

Plant

et al. 2009

Nat. Hazards Earth Syst. Sci.

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Abstract. Satellites carrying X-band Synthetic Aperture Radars (SAR) have recently been launched by several countries. These provide new opportunities to measure precipitation with higher spatial resolution than has heretofore been possible. Two algorithms to retrieve precipitation from such measurements over land have been developed, and the retrieved rainfall distributions were found to be consistent. A maritime rainfall distribution obtained from dual frequency (X and C-band) data was used to compute the Differential Polarized Phase Shift. The computed Differential Polarized Phase Shift compared well with the value measured from space. Finally, we show a comparison between a recent Xband SAR image of a precipitation distribution and an observation of the same rainfall from ground-based operational weather radar. Although no quantitative comparison of retrieved and conventional rainfall distributions could be made with the available data at this time, the results presented here point the way to such comparisons.

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Effects of Nonuniform Beam Filling on Rainfall Retrieval for the TRMM Precipitation Radar

Cited by 63 publications

References 22 publications

Reduction of Nonuniform Beam Filling Effects by Vertical Decorrelation: Theory and Simulations

Reduction of Nonuniform Beam Filling Effects by Vertical Decorrelation: Theory and Simulations

Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land

Rainfall observation from X-band, space-borne, synthetic aperture radar

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