EURADCLIM: the European climatological high-resolution gauge-adjusted radar precipitation dataset

Abstract

Abstract. The European climatological high-resolution gauge-adjusted radar precipitation dataset, EURADCLIM, addresses the need for an accurate (sub)daily precipitation product covering 78 % of Europe at a high spatial resolution. A climatological dataset of 1 and 24 h precipitation accumulations on a 2 km grid is derived for the period 2013 through 2020. The starting point is the European Meteorological Network (EUMETNET) Operational Program on the Exchange of Weather Radar Information (OPERA) gridded radar dataset of 15 min instantaneous surface rain rates, which is based on data from, on average, 138 ground-based weather radars. First, methods are applied to further remove non-meteorological echoes from these composites by applying two statistical methods and a satellite-based cloud-type mask. Second, the radar composites are merged with the European Climate Assessment & Dataset (ECA&D) with potentially ∼ 7700 rain gauges from National Meteorological and Hydrological Services (NMHSs) in order to substantially improve its quality. Characteristics of the radar, rain gauge and satellite datasets are presented, as well as a detailed account of the applied algorithms. The clutter-removal algorithms are effective while removing few precipitation echoes. The usefulness of EURADCLIM for quantitative precipitation estimation (QPE) is confirmed by comparison against rain gauge accumulations employing scatter density plots, statistical metrics and a spatial verification. These show a strong improvement with respect to the original OPERA product. The potential of EURADCLIM to derive pan-European precipitation climatologies and to evaluate extreme precipitation events is shown. Specific attention is given to the remaining artifacts in and limitations of EURADCLIM. Finally, it is recommended to further improve EURADCLIM by applying algorithms to 3D instead of 2D radar data and by obtaining more rain gauge data for the radar–gauge merging. The EURADCLIM 1 and 24 h precipitation datasets are publicly available at https://doi.org/10.21944/7ypj-wn68 (Overeem et al., 2022a) and https://doi.org/10.21944/1a54-gg96 (Overeem et al., 2022b).

Merging with crowdsourced rain gauge data improves pan-European radar precipitation estimates

“…OPERA converts the horizontally polarised radar reflectivity factors to instantaneous surface rain rates using the Marshall-Palmer Z h − R relation (Z h = 200R 1.6 ). The OPERA radar data and the applied algorithms are described in more detail by Saltikoff et al (2019) and Overeem et al (2023).…”

“…Here, two OPERA-based clock-hour radar precipitation datasets are utilised. The processing of these datasets and its characteristics are provided by Overeem et al (2023). For each clock-hour and grid cell, accumulations are only computed in case of full availability of the underlying 15-min data.…”

“…Moreover, these steps only consider the removal of non-meteorological echoes and not the precipitation retrieval itself. The first dataset is an unadjusted OPERA radar dataset, called "OPERA" in this paper and corresponding to "Gabella + CTM + static filter" in Overeem et al (2023). The second dataset is obtained by merging with disaggregated 1-h ECA&D rain gauge accumulations employing a local mean-field bias adjustment succeeded by a spatial adjustment.…”

“…An important reason for the disaggregation is the fact that the measurement interval of daily rain gauge accumulations is not the same for the European NMHSs, which is reflected in ECA&D as the NMHSs are the main source of data. A daily adjustment would therefore be less appropriate (Overeem et al, 2023). This publicly accessible climatological gauge-adjusted product is called "EURADCLIM" (Overeem et al, 2022a, b).…”

“…The merged dataset is evaluated against rain gauge accumulations from the European Climate Assessment & Dataset (ECA&D). Results are also contrasted to those from the European climatological high-resolution gauge-adjusted radar precipitation dataset EURADCLIM (EUropean RADar CLIMatology) (Overeem et al, 2023). In order to assess the performance in case solid precipitation is likely, the evaluation is also performed separately for air temperatures below and above 5 • C.…”