Report from the PDP working group

Transcription

1 Report from the PDP working group Craig Bishop, Pat Harr, Shuhei Maeda, John Methven, Mark Rodwell, Istvan Szunyogh, Olivier Talagrand, Heini Wernli ICSC11 Meeting July 2013

2 PDP mission Main task of the PDP WG: Identify basic research problems with significant importance for NWP and to accelerate the transfer of new techniques from academia to the operational practice. The PDP WG achieves these goals by: Bringing together the academic dynamical meteorology community and the operational NWP centers Encouraging the dynamical meteorology community to carry out process studies with the specific aim to improve the understanding of the relationship between particular processes and weather forecast accuracy.

3 Main activities since ICSC10 Contributions to the WGNE systematic model error workshop in Exeter in April 2013 Contributions to field campaign activities (DIAMET, HYMEX, T-NAWDEX- Falcon) Contributions to planning of post-thorpex activities - Expert team on Predictability, Dynamics and Ensemble Prediction (preparations led by Richard Swinbank) - High-Impact Weather project (preparations led by Brian Golding and Sarah Jones) Organization of DACA-13 conference with session on High-impact weather and extreme climate events led by Richard Swinbank, Istvan Szunyogh et al.

4 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view Christian M. Grams (1) and Heather M. Archambault (2) (1) IAC, ETH Zurich, Switzerland; (2) NPS, Monterey, CA, USA recurvature relative composite of 12 strongest SEP ET cases (Archambault et al. 2013) PV surgery (Grams et al. 2013) Control run + No TC run = Quantification of ET impact on midlatitude flow 335-K PV, wind, and SLP at T-42 h

5 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view control T+0h

6 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view notc T+0h

7 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view control T +48h

8 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view notc T+48h

9 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view control - notc T+48h

10 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view control T +108h

11 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view notc T +108h

12 Quantification of the impact of extratropical transition on the midlatitude flow: A composite view control - notc T +108h

13 Tracing errors back to initial time Z500 from forecasts started at 0 UTC on 10 April 2011 from Mark Rodwell Linus Magnusson Can trace large European day 6 errors back to North America at day 2 but, at shorter leadtimes, uncertianties in analysis are not negligable. Instead, look for best ensemble member and confine perturbations while maintaining small day 6 European error.

14 10 April Rockies trough with CAPE & MCS ahead from Mark Rodwell Z500 and CAPE anomaly Shade unit = 100Jkg -1 30ms hr Radar-observed precipitation Unit = mm Trough CAPE MCS Contour Interval = 100m Z500 at 0UTC, CAPE at 6UTC (T+6), 12hr NEXRAD Radar precipitation accumulated to 9 UTC. MCS is Mesoscale Convective System

15 Ensemble of data assimilations, EDA 10 April T200 mean & spread First-guesses T+12hr Analyses from Mark Rodwell MCS magnifies spread in firstguess New data reduces spread Rodwell et al. (2013) The ensemble of first-guess forecasts develops spread over the first 12 hours associated with uncertainties in the prediction of a mesoscale convective system. The incorporation of new observations by the ensemble of data assimilations results in a contraction of the spread. Key question: Is the final analysis spread too large or too small to correctly reflect the predictability of the subsequent flow? Data: Temperature at 200 hpa from 10-member EDA, valid at 6UTC.

16 Composite ensemble spread & error (Z500 at day 6) from Mark Rodwell Background Trough/CAPE composite Error Spread Error spread (system reliable in the mean). e.g. stormtrack 30% increased error. Spread not fully predicting the reduced predictability? Composite over all 84 events 10 November March 2012 (0 or 12UTC) with a strong trough over the Rockies and positive CAPE ahead. Error is RMSE of ensemble-mean (dominated by random component), Spread is ensemble standard deviation, scaled for finite ensemble

17 DIAMET: Diabatic processes in severe weather systems Vaughan / Methven / Renfrew / Parker

18 DIAMET IOP-8 (8 Dec 2011) First aircraft observations in sting-jet cyclone

19 Field experiment T-NAWDEX-Falcon (October 2012) Cooperation DLR Oberpfaffenhofen, ETH Zurich, University of Mainz

20 T-NAWDEX-Falcon: 3 IOPs (8 flights) in western Europe Instrumentation: H2O gas phase and total (Voigt et al.) FSSP (Bormann & Weigel) trace gases & passive tracer (Schlager et al.) Dropsondes (Busen) Schäfler et al., submitted

21 T-NAWDEX-Falcon: Lagrangian flights in evolving clouds An example from IOP3 Flexpart calculations from flight 3a (blue) show Lagrangian match with flight 3b (black) 6 hours later novel insight in cloud evolution Schäfler et al., submitted

22 T-NAWDEX-Falcon: IOP3 (19/20 Oct) Sharp trough over western Europe with strong southerly jet and intense WCB over UK and the North Sea

23 T-NAWDEX-Falcon: IOP3c (20 Oct 2012) ice cloud at -35 C warm/mixed-phase cloud at 0 to -25 C

24 The extremeness of cyclones extremeness = Σ of local extreme events along track of cyclones extreme precipitation extreme 10-m wind gust cyclone track and area from Christian Grams

25 The extremeness of cyclones First results for YOTC period 05/ /2010 Top 10 extreme cyclones : 9 with tropical origin from Christian Grams

26 The extremeness of cyclones Are fc errors particularly large for extreme cyclones? accum. intensity error extreme cyclones not particularly badly predicted intensity errors seem to be more an issue than track errors accum. track error from Christian Grams

27 T-NAWDEX & DOWNSTREAM Planning towards a cross-atlantic aircraft field experiment in 2016 Scientific objective Investigate physical processes (e.g., aspects of transport, microphysics and radiation involved in formation of pos & neg PV anomalies at tropopause level) in sequence of North Atlantic weather systems potentially involving ET, extratropical cyclones, WCB, blocking & HIW over Europe Aircraft Two G-V from both sides of the Atlantic (HIAPER and HALO), shorter range aircraft from UK, Partners US (Pat Harr, Chris Davis et al.), UK (John Methven and DIAMET community), Germany (DLR, U Munich, DWD), France (Meteo F), Canada (Env. Canada), Switzerland (ETH),