Presentation is loading. Please wait.

Presentation is loading. Please wait.

Polarimetric signatures of Mediterranean storms retrieved by an operational X-band radar system Gianfranco Vulpiani 1, Luca Baldini 2, Elisa Adirosi 2,

Similar presentations


Presentation on theme: "Polarimetric signatures of Mediterranean storms retrieved by an operational X-band radar system Gianfranco Vulpiani 1, Luca Baldini 2, Elisa Adirosi 2,"— Presentation transcript:

1 Polarimetric signatures of Mediterranean storms retrieved by an operational X-band radar system Gianfranco Vulpiani 1, Luca Baldini 2, Elisa Adirosi 2, Nicoletta Roberto 2 1 Department of Civil Protection (DPC), Presidency of the Council of Ministers, Rome, Italy 2 Institute of Atmospheric Sciences and Climate (ISAC), National Research Council, Rome, Italy 8 th European Conference on Radar in Meteorology and Hydrology

2 Overview  Content: Analysis of a couple of severe Mediterranean storms are analyzed in terms of polarimetric radar signatures retrieved by the operational X-band radar  Objective: To demonstrate the potential use of dual-polarized X-band radar system for operational precipitation monitoring in case of severe storms with associated high attenuation, eventually enhanced by hail.  Context: The considered system, managed by the Dept. of Civil Protection (DPC), is part of the national radar network. It was deployed in Catania (Sicily, Italy) in 2010 with the aim to monitor weather and volcanic ash clouds (emitted by the nearby Etna volcano). ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 2

3 The context  “Federated network”: radars managed by regional and national bodies  Currently, it is composed by 20 systems, most of them are polarimetric  2 (+2 available) transportable X-band dual-pol radar radar systems Italian National Weather Radar Network X-band radar Installed at the Catania airport a)gap filler within the national radar network b) Etna Volcano ash monitoring X-band radar Installed at the Catania airport a)gap filler within the national radar network b) Etna Volcano ash monitoring ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 3

4 Catania X-band radar scan strategy 12 PPI sweeps + vertical-incidence used for Z DR calibration Scan frequency: 10 minutes Scan duration: 5 min ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 4

5 Catania X-band radar visibility map 1 deg2 deg 3 deg5 deg ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 5

6 X-band radar data processing  Z DR calibration using available analysis at vertical incidence (Gorgucci et al., 1999)  Fuzzy Logic approach to identify non-weather returns (Vulpiani et al., 2012)  Differential phase processing - Iterative finite-difference scheme with short moving window (Vulpiani et al., 2012):  removes offset, aliasing  keeps under control the STD(K DP ) iterating few times the procedure  Attenuation compensated assuming a linear relation (Bringi et al., 1990, Carey et al., 2000) parameterized by scattering simulations based on DSD measurements collected in central Italy (Adirosi et al., 2014): A h,dp =  h,dp K dp  h =0.29,  dp =0.048 A h,dp =  h,dp K dp  h =0.29,  dp =0.048;  Parametric rainfall estimation using Z-R, R(K DP ) and a composite (R C (Z, K DP ) algorithm (Vulpiani and Baldini, 2013)  A Fuzzy Logic hydrometeor classification is applied to support the analysis ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 6

7 Case study 1  On the Feb. 21 st 2013 a severe storm hit central-eastern Sicily (Italy) flash-flooding the city of Catania (close to the radar site)  Hail was also reported Images taken from: http://www.cataniatoday.it/foto/nubifragio-a-catania-21-febbraio-2013/ ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 7

8 Case study 1  MSG (10.8  m) images (1500-1800 UTC)  Lighting (Last 3 hours) (panel e)  Rain gauge located in Catania 60 mm in between 15:00 and 16:00 UTC about 70 mm in 1 and half hour.  nearby raingauges did not record > 20 mm in 3 hours.  2-m temperature between 10.4 (1530 UTC) and 13.5 (till 1500 UTC) in Catania  FLH ranging between 1.8 and 2.1 km ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 8

9 FLH ML Observations at vertical incidence FLH: Freezing Layer Height ML: Melting Layer 16:50 UTC ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 9

10 VMI of Z at 15:00 UTC Signal extinction ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 10

11 Pseduo RHIs @ azim. 4 (deg) + range plots @ 6 deg elev. - 1500 UTC Distance (km) Z Z DR  HV K DP ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY extintion 11

12 <><>  RMSEFSEBias RZRZ -1.622.122.650.640.61 RKRK -0.362.642.630.640.91 RCRC -0.812.162.280.550.80 Comparison with 26 rain gauges within the radar coverage area Rainfall estimation =   = ( ) 1/2 Bias = / FSE=RMSE/ Radar estimated cumulated precipitation between 1500 and 1800 UTC Radar estimated cumulated precipitation between 1500 and 1800 UTC ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 12

13 Case study 2 21 August 2013  Mesoscale convective system lasted about 5 hours  Intense lightning,  several signal extintion episodes  FLH around 3.4 km at 08 UTC  High precipitation amount (e.g., 135 mm in 1 hour and 186 mm in 2 hours ) FLH ML 05:30 07:00 08:0009:00 MSG (10.8  m) images (0530-0900 UTC) ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 13

14 PPI scans at 0450 and 0500 UTC Probability of Hail: derived by  H=H 45-dBZ -H FL H 45-dBZ = 45-dBZ echo top height H FL = Freezing Layer Height Vertical Maximum Intensity ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 14

15 Pseudo-RHI @ azim 121 deg - 0450 UTC ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY Z Z DR  HV K DP 15

16 Pseudo-RHI @ azim 122 deg - 0450 UTC ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY Z Z DR  HV K DP 16

17 Rainfall estimation 6h cumulated rainfall (mm), 2013-08-21 Siracusa The precipitation peak was underestimated: about 180 mm registered in 2 hours in Siracusa but about 130 mm by the composite algorithm <><>  RMSEFSEBias RZRZ -2.6812.4112.591.710.63 RKRK 0.8810.4410.391.411.12 RCRC -0.629.97 1.360.92 ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 17

18 Summary  This work has documented a couple of severe precipitation events causing the flash flood of Catania and Siracusa (Sicily, Italy) using an operational dual-pol X-band radar;  21 Feb. 2013:  60 mm of rainfall registered in 1 hour (70 mm in 1 and ½ hour),  hail was reported for that event.  HCS is able to confirm the presence of melting hail/rain hail mixture justifying the huge differential phase shift observed in very short path length;  21 Aug. 2013:  flash-flood in Siracusa (186 mm in 2 hours),  strong updraft  high water fraction above the FLH,  RAIN/HAIL mixture caused several signal extinction episodes  Rainfall estimation: K DP is a crucial parameter!  21 Feb.: the close-range precipitation peak was pretty well reconstructed  21 Aug.: relatively good with a trend to underestimation, especially at far range (attenuation, NBF) ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY 18

19 References ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY Adirosi E., L. Baldini, N. Roberto, G. Vulpiani, F. Russ, F. Napolitano, 2014: Using disdrometer measured raindrop size distributions to establish weather radar algorithms, 12th Int. Conf. of numerical analysis and applied mathematics (ICNAAM 2014). AIP Conference Proceedings. Bringi, V. N., V. Chandrasekar, N. Balakrishnan, and D. S. Zrnić, 1990: An examination of propagation effects in rainfall on radar measurements at microwave frequencies. J. Atmos. Oceanic Technol., 7, 829–840. Carey, L. D., S. A. Rutledge, D. A. Ahijevych, and T. D. Keenan, 2000: Correcting propagation effects in C-band polarimetric radar observations of tropical convection using differential propagation phase. J. Appl. Meteor., 39, 1405–1433. Gorgucci, E., G. Scarchilli, and V. Chandrasekar, 1999: A procedure to calibrate multiparameter weather radar using properties of the rain medium. IEEE Trans. Geosci. Rem. Sens., vol. 37, N. 1, 269-276. Vulpiani, G., M. Montopoli, L. D. Passeri, A. Gioia, P. Giordano, and F. S. Marzano, 2012: On the use of dual-polarized C-band radar for operational rainfall retrieval in mountainous areas. J. Appl. Meteor and Clim., 51, 405–425. Vulpiani, G., and L. Baldini, 2013: Observations of a severe hail-bearing storm by an operational X-band polarimetric radar in the mediterranean area. Proceed. of the 36th AMS Conference on Radar Meteorology, Breckenridge, CO, USA. 19

20 20

21  DP processing: example ERAD 2014 - THE EIGHTH EUROPEAN CONFERENCE ON RADAR IN METEOROLOGY AND HYDROLOGY G ARMISCH -P ARTENKIRCHEN G ERMANY Window size: 1km, 5 range gates 21


Download ppt "Polarimetric signatures of Mediterranean storms retrieved by an operational X-band radar system Gianfranco Vulpiani 1, Luca Baldini 2, Elisa Adirosi 2,"

Similar presentations


Ads by Google