General Application of the Relative Calibration Adjustment (RCA) Technique for Monitoring and Correcting Radar Reflectivity Calibration

Wolff, David B.; Marks, David A.; Petersen, Walter A.

doi:10.1175/jtech-d-13-00185.1

Cited by 41 publications

(40 citation statements)

References 11 publications

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“…The analysis has been restricted to 100 km range to make sure we were able to detect 0‐dBZ echo top heights at any included range. The existing 17‐year radar data set was calibrated using a combination of the Relative Calibration Adjustment technique (Wolff et al, ) and statistical comparisons with the NASA TRMM and Global Precipitation Measurement mission precipitation radars in space using the technique described in Warren et al (). Rainfall and cloud types were classified using the method described by Kumar, Jakob, Protat, May, and Davies ().…”

Section: Methodsmentioning

confidence: 99%

The isotopic signature of monsoon conditions, cloud modes, and rainfall type

Zwart

Munksgaard

Protat

et al. 2018

Hydrological Processes

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This work provides a comprehensive physically based framework for the interpretation of the north Australian rainfall stable isotope record ( 18 O and 2 H). Until now, interpretations mainly relied on statistical relationships between rainfall amount and isotopic values on monthly timescales. Here, we use multiseason daily rainfall stable isotope and high resolution (10 min)ground-based C-band polarimetric radar data and show that the five weather types (monsoon regimes) that constitute the Australian wet season each have a characteristic isotope ratio. The data suggest that this is not only due to changes in regional rainfall amount during these regimes but, more importantly, is due to different rain and cloud types that are associated with the large scale circulation regimes. Negative (positive) isotope anomalies occurred when stratiform rainfall fractions were large (small) and the horizontal extent of raining areas were largest (smallest).Intense, yet isolated, convective conditions were associated with enriched isotope values whereas more depleted isotope values were observed when convection was widespread but less intense.This means that isotopic proxy records may record the frequency of which these typical wet season regimes occur. Positive anomalies in paleoclimatic records are most likely associated with periods where continental convection dominates and convection is sea-breeze forced. Negative anomalies may be interpreted as periods when the monsoon trough is active, convection is of the oceanic type, less electric, and stratiform areas are wide spread. This connection between variability of rainfall isotope anomalies and the intrinsic properties of convection and its large-scale environment has important implications for all fields of research that use rainfall stable isotopes.

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Section: Methodsmentioning

confidence: 99%

The isotopic signature of monsoon conditions, cloud modes, and rainfall type

Zwart

Munksgaard

Protat

et al. 2018

Hydrological Processes

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“…GPM GV has established a world‐class inventory of precipitation instrumentation. Equipment developed and operated as part of this instrument suite include the NASA S‐band dual‐polarization (NPOL) radar (Wolff et al ., ), the Ku‐Ka band Dual‐frequency Dual‐Polarimetric Doppler Radar (D3R: Vega et al ., ), numerous Micro Rain Radars (MRR‐2; Peters et al ., ), Pluvio‐2 weighing gauges, dense networks of (multiple) tipping bucket rain‐gauges, snow imaging/measurement systems such as the Precipitation Imaging Package (PIP) (e.g. Newman et al ., ; Tiira et al ., ), and autonomously operating Parsivel and 2D Video Disdrometer (2DVD) networks (e.g.…”

Section: Ground Validation Activities and Contributions To The Gpm MImentioning

confidence: 99%

The Global Precipitation Measurement (GPM) mission's scientific achievements and societal contributions: reviewing four years of advanced rain and snow observations

Skofronick-Jackson

Kirschbaum

Petersen

et al. 2018

Quart J Royal Meteoro Soc

143

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Precipitation represents a life‐critical energy and hydrologic exchange between the Earth's atmosphere and its surface. As such, knowledge of where, when and how much rain and snow falls is essential for scientific research and societal applications. Building on the 17‐year success of the Tropical Rainfall Measurement Mission (TRMM), the Global Precipitation Measurement (GPM) Core Observatory (GPM‐CO) is the first US National Aeronautical and Space Administration (NASA) satellite mission specifically designed with sensors to observe the structure and intensities of both rain and falling snow. The GPM‐CO has proved to be a worthy successor to TRMM, extending and improving high‐quality active and passive microwave observations across all times of day. The GPM‐CO launched in early 2014, is a joint mission between NASA and the Japanese Aerospace Exploration Agency (JAXA), with sensors that include the NASA‐provided GPM Microwave Imager and the JAXA‐provided Dual‐frequency Precipitation Radar. These sensors were devised with high accuracy standards enabling them to be used as a reference for inter‐calibrating a constellation of partner satellite data. These inter‐calibrated partner satellite retrievals are used with infrared data to produce merged precipitation estimates at temporal scales of 30 min and spatial scales of 0.1° × 0.1°. Precipitation estimates from the GPM‐CO and partner constellation satellites, provided in near real time and later reprocessed with all ancillary data, are an indispensable source of precipitation data for operational and scientific users. Advances have been made using GPM data, primarily in improving sensor calibration, retrieval algorithms, and ground validation measurements, and used to further our understanding of the characteristics of liquid and frozen precipitation and the science of water and hydrological cycles for climate/weather forecasting. These advances have extended to societal benefits related to water resources, operational numerical weather prediction, hurricane monitoring, prediction, and disaster response, extremes, and disease.

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“…The error bars represent the estimated uncertainty. In the Sun calibration, the DRAO reference at 20:00 UTC, as reported in Wolff et al (2015), is subtracted from the observed solar power. The vertical blue lines divide the study period in three sectors as reported in the text.…”

Section: Discussionmentioning

confidence: 99%

“…The method of the ground clutter calibration is based on a clutter mask that is used to select clutter echoes that appear very frequently in the radar images. This is intended to minimize the possible contamination by meteorological echoes (Silberstein et al, 2008 andWolff et al, 2015). The radar volumes are processed by the hydrometeor classification algorithm (Bechini and Chandrasekar, 2015) to identify clutter and meteorological echoes.…”

Section: Ground Clutter Calibrationmentioning

confidence: 99%

“…The calibration using the solar interferences was first proposed by Whiton et al (1976) and has been subsequently applied on operational radars for the monitoring of the radar receiver chain and antenna pointing (Holleman and Beekhuis, 2004;Huuskonen and Holleman, 2007;Holleman et al, 2010a, b;Huuskonen et al, 2014;Gabella et al, 2014 andAltube et al, 2015). The ground clutter calibration allows the stability of the radar calibration to be monitored automatically, specifically the transmitting and receiving chain of both polarization channels, through statistical analysis of the echo power return from fixed targets (Silberstein et al, 2008 andWolff et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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An integrated approach to monitoring the calibration stability of operational dual-polarization radars

et al. 2016

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Abstract. The stability of weather radar calibration is a mandatory aspect for quantitative applications, such as rainfall estimation, short-term weather prediction and initialization of numerical atmospheric and hydrological models. Over the years, calibration monitoring techniques based on external sources have been developed, specifically calibration using the Sun and calibration based on ground clutter returns. In this paper, these two techniques are integrated and complemented with a self-consistency procedure and an intercalibration technique. The aim of the integrated approach is to implement a robust method for online monitoring, able to detect significant changes in the radar calibration. The physical consistency of polarimetric radar observables is exploited using the self-consistency approach, based on the expected correspondence between dual-polarization power and phase measurements in rain. This technique allows a reference absolute value to be provided for the radar calibration, from which eventual deviations may be detected using the other procedures. In particular, the ground clutter calibration is implemented on both polarization channels (horizontal and vertical) for each radar scan, allowing the polarimetric variables to be monitored and hardware failures to promptly be recognized. The Sun calibration allows monitoring the calibration and sensitivity of the radar receiver, in addition to the antenna pointing accuracy. It is applied using observations collected during the standard operational scans but requires long integration times (several days) in order to accumulate a sufficient amount of useful data. Finally, an intercalibration technique is developed and performed to compare colocated measurements collected in rain by two radars in overlapping regions. The integrated approach is performed on the C-band weather radar network in northwestern Italy, during July-October 2014. The set of methods considered appears suitable to establish an online tool to monitor the stability of the radar calibration with an accuracy of about 2 dB. This is considered adequate to automatically detect any unexpected change in the radar system requiring further data analysis or on-site measurements.

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General Application of the Relative Calibration Adjustment (RCA) Technique for Monitoring and Correcting Radar Reflectivity Calibration

Cited by 41 publications

References 11 publications

The isotopic signature of monsoon conditions, cloud modes, and rainfall type

The isotopic signature of monsoon conditions, cloud modes, and rainfall type

The Global Precipitation Measurement (GPM) mission's scientific achievements and societal contributions: reviewing four years of advanced rain and snow observations

An integrated approach to monitoring the calibration stability of operational dual-polarization radars

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