VERIFICATION OF THE LAMI AT CNMCA

1. VERIFICATION OF THE LAMI AT CNMCA by Adriano Raspanti, Patrizio Emiliani, Alessandro Galliani+ E-mail: name.surname@meteoam.it Presented by Adriano Raspanti COSMO general meeting – Zurich 20-23 September 2005 – WG5

2. CONTENTS VERIFICATION OF THE LAMI AT CNMCA • Objective verifications only for surface variables • Continuous variables: T2m, TD2m,10m wind speed,Mslp; • Verifications for precipitations; • Results for winter, spring and summer 2005 (of course early results); • Stratifications for different areas; • Some verifications against previous years; • Some confrontations vs. Ecmwf model (precipitations only); • Preliminary results from subjective/qualitative verifications of LAMI COSMO general meeting – Zurich 20-23 September 2005 – WG5

3. VERIFICATION OF THE LAMI AT CNMCA • Strong negative bias in winter • Strong positive mae (low abs accuracy) • in summer around midday COSMO general meeting – Zurich 20-23 September 2005 – WG5

4. VERIFICATION OF THE LAMI AT CNMCA • Positive bias in winter COSMO general meeting – Zurich 20-23 September 2005 – WG5

5. VERIFICATION OF THE LAMI AT CNMCA • Positive bias for all the seasons (low mae in summer – weak circulation) • Diurnal cycle in spring and summer (overestimation during night – weak underestimation daytime) COSMO general meeting – Zurich 20-23 September 2005 – WG5

6. VERIFICATION OF THE LAMI AT CNMCA • Quasi-Linear increment of mae with the ranges • Negative bias for d+2 during summer COSMO general meeting – Zurich 20-23 September 2005 – WG5

7. VERIFICATION OF THE LAMI AT CNMCA • Diurnal cycle • Strong positive mae (low abs accuracy) • in summer around midday (since may) • The model is cold during afternoon COSMO general meeting – Zurich 20-23 September 2005 – WG5

8. VERIFICATION OF THE LAMI AT CNMCA • General overestimation especially in winter COSMO general meeting – Zurich 20-23 September 2005 – WG5

9. VERIFICATION OF THE LAMI AT CNMCA • Strong negative bias in winter • Strong positive mae (low abs accuracy) • in summer around midday COSMO general meeting – Zurich 20-23 September 2005 – WG5

10. VERIFICATION OF THE LAMI AT CNMCA • General overestimation for all seasons COSMO general meeting – Zurich 20-23 September 2005 – WG5

11. VERIFICATION OF THE LAMI AT CNMCA • In winter (and less in spring) the performance is better due to the type of precipitations (mainly large scale) • In summer shift in convective daily precipitations (model anticipates the occurrence) COSMO general meeting – Zurich 20-23 September 2005 – WG5

12. VERIFICATION OF THE LAMI AT CNMCA • Same consideration as the previous slide COSMO general meeting – Zurich 20-23 September 2005 – WG5

13. VERIFICATION OF THE LAMI AT CNMCA • Note in summer the range 12-24 has the best performance (with a low frequency bias) COSMO general meeting – Zurich 20-23 September 2005 – WG5

14. VERIFICATION OF THE LAMI AT CNMCA • Note the low FBI especially in winter and spring COSMO general meeting – Zurich 20-23 September 2005 – WG5

15. VERIFICATION OF THE LAMI AT CNMCA • improvement in FBI values compare to winter 2004 (and 2003 but it was without nudging) COSMO general meeting – Zurich 20-23 September 2005 – WG5

16. VERIFICATION OF THE LAMI AT CNMCA • Note the low 2005 FBI compared to 2004 also in a rainy summer (afternoon ranges) COSMO general meeting – Zurich 20-23 September 2005 – WG5

17. With this project (taken from an original idea by Carlo Cacciamani) we would like to understand the behaviour of the model not only from a quantitative point of view but also from qualitative (and then subjective) one.Another main goal is to develop the sensibility of the forecaster in using and then in understanding the different “sensibility” of the model in a number of different weather regimes situations.We use a simple excel file with pre-fixed items to describe weather regimes, synoptic and mesoscale features and so on, in order to give to the different runs and ranges a sort of good/bad score.What follows are the results of the march-august subjective verification VERIFICATION OF THE LAMI AT CNMCA(subjective – a new program) COSMO general meeting – Zurich 20-23 September 2005 – WG5

18. This is the form used by our forecasters VERIFICATION OF THE LAMI AT CNMCA(subjective – a new program) In these six months (say spring and summer) we have found some interesting results:The model seems to “prefer” to forecast synoptic situations with the characteristic associated features: for example frontal and large scale precipitations, both in spring and summer (in this rainy summer!!!)No particular weather regime seems to be better predictable except maybe for the SW, generally more slow and often characterized by well-developed frontal zones;A very good identification of strong wind events;Some problems with the detection of fogs (using Automatic Weather interpretation tool) except in march, maybe due to the 2mT and humidity fields forecasts and to the algorithms used; COSMO general meeting – Zurich 20-23 September 2005 – WG5

19. 112 cases of good or very good forecasts vs. a total of 192 in summer (58%); • 196 cases of good or very good forecasts vs. a total of 295 in spring (66%) • The “quality” of the model decreases quasi-monotonically from march to august (except for June when is really bad!!!), probably due to the change of precipitations nature (from slow and frontal to mainly convective and fast). • To be continued…. VERIFICATION OF THE LAMI AT CNMCA (subjective – a new program) COSMO general meeting – Zurich 20-23 September 2005 – WG5