Use of the Surface Reference Technique for Path Attenuation Estimates from the TRMM Precipitation Radar

Meneghini, R.; Iguchi, Toshio; Kozu, Toshiaki; Liao, Liang; Okamoto, Ken‐ichi; Jones, Jeffrey A.; Kwiatkowski, John

doi:10.1175/1520-0450(2001)040<2053:uotsrt>2.0.co;2

Cited by 230 publications

(126 citation statements)

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“…The PR attenuation correction is adequate in stratiform rain but is underestimated in convective rain, particularly for heavy rain accumulations (Liao and Meneghini, 2009). Generally, application of the attenuation correction can change the estimated rain rate by an order of magnitude in cases of heavy precipitation (Bindlish and Barros, 2000;Iguchi et al, 2000;Meneghini et al, 2000). Generally, the NUBF effects refer to underestimation errors in the presence of reflectivity gradients, that is, subgrid-scale volume heterogeneity at the relatively coarse resolution of the PR footprint (Durden et al, 1998;Nakamura, 1991).…”

Section: Trmm Pr 2a25 Productsmentioning

confidence: 99%

Scoping a field experiment: error diagnostics of TRMM precipitation radar estimates in complex terrain as a basis for IPHEx2014

Duan

Wilson

Barros

2015

Hydrol. Earth Syst. Sci.

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Abstract.A diagnostic analysis of the space-time structure of error in quantitative precipitation estimates (QPEs) from the precipitation radar (PR) on the Tropical Rainfall Measurement Mission (TRMM) satellite is presented here in preparation for the Integrated Precipitation and Hydrology Experiment (IPHEx) in 2014. IPHEx is the first NASA ground-validation field campaign after the launch of the Global Precipitation Measurement (GPM) satellite. In anticipation of GPM, a science-grade high-density raingauge network was deployed at mid to high elevations in the southern Appalachian Mountains, USA, since 2007. This network allows for direct comparison between ground-based measurements from raingauges and satellite-based QPE (specifically, PR 2A25 Version 7 using 5 years of data [2008][2009][2010][2011][2012][2013]. Case studies were conducted to characterize the vertical profiles of reflectivity and rain rate retrievals associated with large discrepancies with respect to ground measurements. The spatial and temporal distribution of detection errors (false alarm, FA; missed detection, MD) and magnitude errors (underestimation, UND; overestimation, OVR) for stratiform and convective precipitation are examined in detail toward elucidating the physical basis of retrieval error.The diagnostic error analysis reveals that detection errors are linked to persistent stratiform light rainfall in the southern Appalachians, which explains the high occurrence of FAs throughout the year, as well as the diurnal MD maximum at midday in the cold season (fall and winter) and especially in the inner region. Although UND dominates the error budget, underestimation of heavy rainfall conditions accounts for less than 20 % of the total, consistent with regional hydrometeorology. The 2A25 V7 product underestimates lowlevel orographic enhancement of rainfall associated with fog, cap clouds and cloud to cloud feeder-seeder interactions over ridges, and overestimates light rainfall in the valleys by large amounts, though this behavior is strongly conditioned by the coarse spatial resolution (5 km) of the topography mask used to remove ground-clutter effects. Precipitation associated with small-scale systems (< 25 km 2 ) and isolated deep convection tends to be underestimated, which we attribute to non-uniform beam-filling effects due to spatial averaging of reflectivity at the PR resolution. Mixed precipitation events (i.e., cold fronts and snow showers) fall into OVR or FA categories, but these are also the types of events for which observations from standard ground-based raingauge networks are more likely subject to measurement uncertainty, that is raingauge underestimation errors due to undercatch and precipitation phase.Overall, the space-time structure of the errors shows strong links among precipitation, envelope orography, landform (ridge-valley contrasts), and a local hydrometeorological regime that is strongly modulated by the diurnal cycle, pointing to three major error causes that are inter-related: (1) representation of concurren...

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Section: Trmm Pr 2a25 Productsmentioning

confidence: 99%

Scoping a field experiment: error diagnostics of TRMM precipitation radar estimates in complex terrain as a basis for IPHEx2014

Duan

Wilson

Barros

2015

Hydrol. Earth Syst. Sci.

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“…total of 80 vertical levels). The 2A25 algorithm relies on a hybrid attenuation correction method which combines the surface reference technique (SRT) and Hitschfeld-Bordan method Meneghini et al, 2000;Meneghini et al, 2004). Retrieval errors of the algorithm are mainly attributed to the uncertainty of the a prioi selected drops size distribution (DSD), incorrect physical assumptions (freezing height, hydrometeor temperatures) and non-uniform beam filling (NUBF) effects (Iguchi et al, 2009).…”

Section: Trmm 2a25mentioning

confidence: 99%

Analyzing coastal precipitation using TRMM observations

2011

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Abstract.The interaction between breezes and synoptic gradient winds, and surface friction increase in transition from sea to land can create persistent convergence zones nearby coastlines. The low level convergence of moist air promotes the dynamical and microphysical processes responsible for the formation of clouds and precipitation.Our work focuses on the winter seasons of 1998-2011 in the Eastern Mediterranean. During the winter the Mediterranean sea is usually warmer than the adjacent land, resulting in frequent occurrence of land breeze that opposes the common synoptic winds. Using rain-rate vertical profiles from the Tropical Rainfall Measurement Mission (TRMM) satellite, we examined the spatial and temporal distribution of average hydrometeor mass in clouds as a function of the distance from coastlines.Results show that coastlines in the Eastern Mediterranean are indeed favored areas for precipitation formation. The intra-seasonal and diurnal changes in the distribution of hydrometeor mass indicate that the land breeze may likely be the main responsible mechanism behind our results.

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“…It also uses a PR-based climatology of cloud-fiee surface radar crosssections (Or) to ultimately prescribe path attenuation (A) profile properties if a measured near-, surface range-gate Z factor is not reconciled by the downward accumulated Hitschfeld-Bordan generated total path attenuation ( P A ) . This adjustment involves the surface reference technique (SRT) developed by Meneghini et al (2000); also see Menegluni and Kozu (1990). This means that if the initial top-down ITA estimated fiom a unified pair of Z-R and Z-A relationships used in the rainrate conversion equations do not satisfy the measured 2 factor measured just above the surface, the power law coefficients intrinsic to the Z-R and Z-A relationships are adjusted to ensure that the final R and A profiles give rise to the TPA directly estimated fiom the SRT.…”

Section: Description Of Datasetsmentioning

confidence: 99%

Mechanisms for Diurnal Variability of Global Tropical Rainfall Observed from TRMM

2006

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The behavior and various controls of diurnal variability in tropical–subtropical rainfall are investigated using Tropical Rainfall Measuring Mission (TRMM) precipitation measurements retrieved from the three level-2 TRMM standard profile algorithms for the 1998 annual cycle. Results show that diurnal variability characteristics of precipitation are consistent for all three algorithms, providing assurance that TRMM retrievals are producing consistent estimates of rainfall variability. As anticipated, most ocean areas exhibit more rainfall at night, while over most land areas, rainfall peaks during daytime; however, important exceptions are noted. The dominant feature of the oceanic diurnal cycle is a rainfall maximum in late-evening–early-morning (LE–EM) hours, while over land the dominant maximum occurs in the mid- to late afternoon (MLA). In conjunction with these maxima are pronounced seasonal variations of the diurnal amplitudes. Amplitude analysis shows that the diurnal pattern and its seasonal evolution are closely related to the rainfall accumulation pattern and its seasonal evolution. In addition, the horizontal distribution of diurnal variability indicates that for oceanic rainfall, there is a secondary MLA maximum coexisting with the LE–EM maximum at latitudes dominated by large-scale convergence and deep convection. Analogously, there is a preponderancy for an LE–EM maximum over land coexisting with the stronger MLA maximum, although it is not evident that this secondary continental feature is closely associated with the large-scale circulation. Neither of the secondary maxima exhibit phase behavior that can be considered semidiurnal in nature. Diurnal rainfall variability over the ocean associated with large-scale convection is clearly an integral component of the general circulation. Phase analysis reveals differences in regional and seasonal features of the diurnal cycle, indicating that underlying forcing mechanisms differ from place to place. This is underscored by the appearance of secondary ocean maxima in the presence of large-scale convection, along with other important features. Among these, there are clear-cut differences between the diurnal variability of seasonal rainfall over the mid-Pacific and Indian Ocean Basins. The mid-Pacific exhibits double maxima in spring and winter but only LE–EM maxima in summer and autumn, while the Indian Ocean exhibits double maxima in spring and summer and only an LE–EM maximum in autumn and winter. There are also evident daytime maxima within the major large-scale marine stratocumulus regions off the west coasts of continents. The study concludes with a discussion concerning how the observational evidence either supports or repudiates possible forcing mechanisms that have been suggested to explain diurnal rainfall variability.

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Use of the Surface Reference Technique for Path Attenuation Estimates from the TRMM Precipitation Radar

Cited by 230 publications

References 19 publications

Scoping a field experiment: error diagnostics of TRMM precipitation radar estimates in complex terrain as a basis for IPHEx2014

Scoping a field experiment: error diagnostics of TRMM precipitation radar estimates in complex terrain as a basis for IPHEx2014

Analyzing coastal precipitation using TRMM observations

Mechanisms for Diurnal Variability of Global Tropical Rainfall Observed from TRMM

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