Calibration of Two X-Band Ground Radars Against GPM DPR Ku-Band
Journal
Remote Sensing
Date Issued
May 14, 2025
DOI
10.3390/rs17101712
Abstract
Weather radars are essential in the Quantitative Precipitation Estimates (QPE) but
are susceptible to calibration errors. Previous work demonstrated that observations from
the Ku-band Dual Polarization Radar (DPR) radar on board the Global Precipitation Measurement
Mission Dual-Precipitation Radar (GPM) are suitable for ground radar calibration.
Several studies volume-matched ground radar and GPM DPR Ku-band reflectivities for
the absolute calibration of ground radars, by applying different constraints and filters in
the volume-matching procedure. This study compares and evaluates volume-matching
thresholds and data filtering schemes for the Rizoelia, Larnaca (LCA) and Nata, Pafos (PFO)
radars of the Cyprus weather radar network from October 2017 till May 2023. Excluding
reflectivities below and within the melting layer with a 250 m buffer yielded consistent
results for both ground radars. The selected calibration schemes were combined, and
the resulting offsets were compared to stable radar parameters to identify stable calibration
periods. The consistency of the wet hydrological year October 2019 to September
2020 suggests that radar calibration results are prone to differences in meteorological conditions,
as scarce rainfall can result in insufficient data for reliable calibration. Future
work will incorporate disdrometer measurements and extend the analysis to quantitative
precipitation estimation.
are susceptible to calibration errors. Previous work demonstrated that observations from
the Ku-band Dual Polarization Radar (DPR) radar on board the Global Precipitation Measurement
Mission Dual-Precipitation Radar (GPM) are suitable for ground radar calibration.
Several studies volume-matched ground radar and GPM DPR Ku-band reflectivities for
the absolute calibration of ground radars, by applying different constraints and filters in
the volume-matching procedure. This study compares and evaluates volume-matching
thresholds and data filtering schemes for the Rizoelia, Larnaca (LCA) and Nata, Pafos (PFO)
radars of the Cyprus weather radar network from October 2017 till May 2023. Excluding
reflectivities below and within the melting layer with a 250 m buffer yielded consistent
results for both ground radars. The selected calibration schemes were combined, and
the resulting offsets were compared to stable radar parameters to identify stable calibration
periods. The consistency of the wet hydrological year October 2019 to September
2020 suggests that radar calibration results are prone to differences in meteorological conditions,
as scarce rainfall can result in insufficient data for reliable calibration. Future
work will incorporate disdrometer measurements and extend the analysis to quantitative
precipitation estimation.
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