Evaluation of operational usability of current radar products in estimation of precipitation type

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00020699%3A_____%2F24%3AN0000110" target="_blank" >RIV/00020699:_____/24:N0000110 - isvavai.cz</a>

Result on the web

—

DOI - Digital Object Identifier

—

Result language

angličtina

Original language name

Evaluation of operational usability of current radar products in estimation of precipitation type

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 two weather radars covering the area of the Czech Republic. Both radars were replaced in 2015 by C-band Doppler polarimetric radars Vaisala WRM 200. Before modernization of Czech weather radar network, with single-pol radar measurements, the only radar-based estimation of precipitation type was discrimination between hail vs. no hail occurrence in convective storms. Two reflectivity-based algorithms for hail identification (POH algorithm proposed by Waldvogel and POSH/MEHS proposed by Witt et al.) were implemented in CHMI. After modernization, hail identification became possible also by Vaisala HYDROCLASS polarimetric hydrometeor classification algorithm. In this case we extrapolated presence of hail identified in the lowest PPI to the ground under rough assumption that hail will not melt completely. All of these hail detection algorithms have been evaluated against ground observations and proved their usefulness. Polarimetric hydrometeor classification algorithms together with improved polarimetric bright-band detection enable general discrimination between solid and liquid phase and various hydrometeor types but unfortunately, contrary to user requirements, because of geometric limitations of radar measurements (over the Czech territory the lowest available radar measurement is typically several hundred meters above ground) they can’t discriminate precipitation type on the ground. With the exception of hail, estimation of precipitation type on the ground is currently available in CHMI only as an output of ALADIN numerical model. As it is a forecasted field, it is affected by uncertainties of numerical model forecast both in location and precipitation type. Hence, there is room for improvement of numerical model outputs by combining them with radar data. Radar measurements might be used for correction of precipitation location. Polarimetric hydrometeor classification and bright-band height detection might be used for correction of precipitation type available from ALADIN in suitable cases and locations. Evaluation of possible corrections is now under way. The contribution presents current work on implementation and evaluation of precipitation type based on above mentioned radar measurements and their combination with numerical model forecasts.

Czech name

—

Czech description

—

Type

O - Miscellaneous

CEP classification

—

OECD FORD branch

10509 - Meteorology and atmospheric sciences

Project

—

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