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<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2026-2031</article-id>
<title-group>
<article-title>Scale dependence of precipitation structure using Tweedie Poisson&amp;ndash;Gamma scaling: an Estonian case study from radar composites and gauges</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Tsoi</surname>
<given-names>Yee Chun</given-names>
<ext-link>https://orcid.org/0009-0007-7644-1637</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Männik</surname>
<given-names>Aarne</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rikka</surname>
<given-names>Sander</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Marine Systems, Tallinn University of Technology, Tallinn, 19086, Estonia</addr-line>
</aff>
<pub-date pub-type="epub">
<day>14</day>
<month>04</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>29</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Yee Chun Tsoi et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2031/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2031/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2031/egusphere-2026-2031.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2031/egusphere-2026-2031.pdf</self-uri>
<abstract>
<p>We characterize precipitation structure over Estonia and the surrounding region using Tweedie Poisson&amp;ndash;Gamma scaling, with Tweedie power as a descriptor of aggregation-dependent mean&amp;ndash;variance behaviour in zero-inflated, heavily-positive-skewed precipitation. The study extends existing Tweedie precipitation analysis to the joint examination of temporal aggregation, seasonality, spatial variability, and observing-system differences. The analysis uses a 1 km, 5 min radar composite derived from the two Estonian C-band radars together with an OTT Pluvio&lt;sup&gt;2&lt;/sup&gt; L gauge network over September 2020 to August 2024. For accumulation lengths from sub-hour to daily windows, is estimated from block-wise mean and variance statistics using ordinary least squares, with availability filtering to handle missing radar timestamps and matched window sampling for radar&amp;ndash;gauge comparison.&lt;/p&gt;
&lt;p&gt;Across all data sources, &lt;em&gt;p&lt;/em&gt; increases with accumulation length, showing that temporal aggregation changes precipitation mean&amp;ndash;variance scaling. Seasonal separation is also clear, with generally highest in summer and lowest in winter, and winter showing the strongest increase with accumulation. Spatially, the all-year radar fields show strong scale dependence but only weak geographical contrasts at fixed accumulation length, whereas seasonal maps show clearer heterogeneity at longer windows. Radar-based at station locations is generally higher than gauge-based estimates, and the magnitude and spread of the differences depend on accumulation length and gauge temporal resolution. These results show that should not be used as a fixed precipitation parameter transferable across durations, seasons, space, or products. Instead, it provides a scale-aware benchmark for evaluating precipitation consistency in generated, corrected, or forecast products, such as quantitative precipitation estimation, downscaling, and nowcasting.</p>
</abstract>
<counts><page-count count="29"/></counts>
</article-meta>
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