Improvements of Czech combined radar - rain gauge QPE aimed at meeting hydrologists needs

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00020699%3A_____%2F24%3AN0000111" target="_blank" >RIV/00020699:_____/24:N0000111 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Improvements of Czech combined radar - rain gauge QPE aimed at meeting hydrologists needs

Original language description

POSTER conference: 12th European Conference on Radar in Meteorology and Hydrology, 9.-13.9.2024. Rome, Italy The Czech Hydrometeorological Institute (CHMI) operates the Czech weather radar network (CZRAD) which consists of 2 C-band polarimetric doppler radars covering the whole area of the Czech Republic and its neighborhood. The CZRAD measurements are used mainly for convective storms warnings and quantitative precipitation estimates (QPE) and forecasts (QPF) based on the COTREC extrapolation method. Every 10 minutes, an advanced QPE merging algorithm MERGE2 is initiated that generates combined radar-raingauge QPE and also an adjustment coefficient applicable to radar-only QPE and QPF. Radar-only QPE and adjusted radar QPE and QPF are updated every 5 minutes. Different radar-based QPEs are used by a wide range of users and applications, a very important part is hydrological modeling and warning. In the past, radar-based QPE and QPF were used mainly in standard conceptual hydrological models focused on larger areas and longer lasting precipitation events. In the recent years focus was shifted towards their utilization in flash flood nowcasting systems. Currently, both radar-based QPE and QPF are used in the CHMI operational Flash Flood Indicator (FFI) hydrological nowcasting system. Use of these products in FFI revealed some specific problems and new requirements that had to be solved. Development was mainly focused on new quality-based compositing of radar data, upgrade of adjustment coefficient algorithm and splitting of combined radar-raingauge QPEs into shorter intervals based on radar measurements. Recent development is focused on calculation of combined QPEs in situation when standard merging algorithm cannot be used because of limited number of available raingauge measurements or because of low correlation between radar and raingauge measurements caused typically be the limitations of uncertainty of radar measurements. The contribution describes CHMI ́s operational production chain composed of radar-based QPE and QPF and their use in hydrological application with focus on flash flood nowcasting. It discusses specific new requirements for radar-based QPE and QPF demanded by flash flood nowcasting applications, and the combined QPE calculation improvements that have been either implemented or that are currently under development to meet these new requirements.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10509 - Meteorology and atmospheric sciences

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů