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Earth Syst. Sci. Discuss., 10,Hydrology 11643–11710, and 2013 Hydrology and www.hydrol-earth-syst-sci-discuss.net/10/11643/2013/Earth System Earth System doi:10.5194/hessd-10-11643-2013 HESSD © Author(s) 2013. CC Attribution 3.0 License.Sciences Sciences Discussions 10, 11643–11710, 2013 Open Access Open Access Ocean Science This discussion paper is/hasOcean been under Science review for the journal Hydrology and Earth System Overview of the first Discussions Sciences (HESS). Please refer to the corresponding final paper in HESS if available. HyMeX special observation period Open Access Open Access over Italy Solid Earth Overview of theSolid first Earth HyMeX Special Observation Period over Italy: Discussions R. Ferretti et al. observations and modelOpen Access results Open Access The Cryosphere The Cryosphere Title Page Discussions 1 1 1 1 1,2 3 R. Ferretti , E. Pichelli , S. Gentile , I. Maiello , D. Cimini , S. Davolio , Abstract Introduction M. M. Miglietta4, G. Panegrossi5, L. Baldini5, F. Pasi6, F. S. Marzano1,7, Conclusions References A. Zinzi8,16,17, S. Mariani9, M. Casaioli9, G. Bartolini10, N. Loglisci11, 12 12 13 13 14 A. Montani , C. Marsigli , A. Manzato , A. Pucillo , M. E. Ferrario , Tables Figures V. Colaiuda1, and R. Rotunno15 1CETEMPS, Department of Physics, University of L’Aquila, L’Aquila, Italy J I 2Institute of Methodologies for Environmental Analysis, CNR IMAA, Potenza, Italy J I 3Institute of Atmospheric Sciences and Climate, CNR ISAC, Bologna, Italy 4Institute of Atmospheric Sciences and Climate, CNR ISAC, Lecce, Italy Back Close 5Institute of Atmospheric Sciences and Climate, CNR ISAC, Roma, Italy 6Institute of Biometeorology, CNR IBIMET, Firenze, Italy Full Screen / Esc 7Department of Information Engineering, Electronics and Telecommunications DIET, Sapienza University, Roma, Italy Printer-friendly Version 8ASI, ASDC Frascati, Italy 9Institute for Environmental Protection and Research, ISPRA, Roma, Italy Interactive Discussion 11643 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 10LaMMA Consortium, Firenze, Italy 11ARPA Piemonte – Weather Forecasting Department, Torino, Italy HESSD 12ARPA Emilia Romagna – SIMC, Bologna, Italy 10, 11643–11710, 2013 13ARPA Friuli Venezia Giulia – OSMER, Visco, Udine, Italy 14ARPA Veneto, Teolo, Padova, Italy 15NCAR, Boulder, CO, USA Overview of the first 16INAF-OAR, Monte Porzio Catone, Rome, Italy HyMeX special 17 University of Naples “Parthenope”, Naples, Italy observation period Received: 31 July 2013 – Accepted: 5 September 2013 – Published: 23 September 2013 over Italy Correspondence to: R. Ferretti ([email protected]) R. Ferretti et al. Published by Copernicus Publications on behalf of the European Geosciences Union. Title Page Abstract Introduction Conclusions References Tables Figures J I J I Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 11644 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract HESSD During the first Hymex campaign (5 September–6 November 2012) referred to as Spe- cial Observation Period (SOP-1), dedicated to heavy precipitation events and flash 10, 11643–11710, 2013 floods in Western Mediterranean, three Italian hydro-meteorological monitoring sites 5 were activated: Liguria-Tuscany, North-Eastern Italy and Central Italy. The extraordi- Overview of the first nary deployment of advanced instrumentation, including instrumented aircrafts, and HyMeX special the use of several different operational weather forecast models has allowed an un- observation period precedented monitoring and analysis of high impact weather events around the Italian over Italy hydro-meteorological sites. This activity has seen the strict collaboration between the 10 Italian scientific and operational communities. In this paper, an overview of the Italian R. Ferretti et al. organization during the SOP-1 is provided, and selected Intensive Observation Periods (IOPs) are described. A significant event for each Italian target area is chosen for this analysis: IOP2 (12–13 September 2012) in North-Eastern Italy, IOP13 (15–16 October Title Page 2012) in Central Italy and IOP19 (3–5 November 2012) in Liguria and Tuscany. For each Abstract Introduction 15 IOP the meteorological characteristics, together with special observations and weather forecasts, are analyzed with the aim of highlighting strengths and weaknesses of the Conclusions References forecast modeling systems. Moreover, using one of the three events, the usefulness of Tables Figures different operational chains is highlighted. J I 1 Introduction J I 20 The HYdrological cycle in the Mediterranean Experiment (HyMeX, http://www.hymex. Back Close org; Drobinski et al., 2013) is an international experimental programme that aims at advancing the scientific knowledge of the water cycle variability in the Mediterranean Full Screen / Esc basin. This goal is pursued through monitoring, analysis and modelling of the re- gional hydrological cycle in a seamless approach. Its multidisciplinary research ac- Printer-friendly Version 25 tivity investigates phenomena at different temporal and spatial scales, from the inter- annual/decadal variability of the Mediterranean coupled system (atmosphere-land- Interactive Discussion 11645 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ocean) to the single event of severe weather. In this context, a special emphasis is given to the occurrence of heavy precipitation and floods, considering also the associ- HESSD ated impacts on society. 10, 11643–11710, 2013 The motivation for improving our understanding and the predictability of hydro- 5 meteorological hazards stems from the peculiar characteristics of the Mediterranean region, a nearly enclosed basin surrounded by both highly urbanized and complex ter- Overview of the first rain close to the coast that makes the Mediterranean area prone to natural hazards HyMeX special related to the water cycle. In particular, during the autumn season, when the sea is still observation period relatively warm, the large thermal gradient with the atmosphere allows for intense heat over Italy 10 and moisture fluxes (Duffourg and Ducrocq, 2011, 2013) and therefore the Mediter- ranean is often affected by heavy rainfall and floods, which are responsible for most of R. Ferretti et al. the natural disasters in the region. Given the central position of Italy in the Mediterranean basin, it is particularly af- Title Page fected by severe weather phenomena and by the consequent hydro-geological ef- 15 fects; hence the interest in improving knowledge and forecasting of disastrous severe Abstract Introduction weather events is clear for both scientific research and the operational activities. Con- sistent with the HyMeX programme, within the Western Mediterranean Target Area (TA) Conclusions References three hydro-meteorological sites were identified over Italy (Fig. 1): Liguria-Tuscany (LT), Tables Figures North-Eastern Italy (NEI) and Central Italy (CI). These sites were selected because 20 they are representative of the mechanisms responsible for most of the heavy precip- J I itation and flood events affecting the Italian territory, which can be related to specific large-scale patterns (Tartaglione et al., 2009). For example, the severe weather events J I that occurred over the Alps in recent years (Rotunno and Houze, 2007; Mariani et al., Back Close 2009; Barbi et al., 2012) or in Liguria and Lazio during the autumn of 2011 (Buzzi et 25 al., 2012; Ferretti et al, 2012; Parodi et al., 2012; Rebora et al., 2013), are directly Full Screen / Esc (e.g. orographic precipitation) or indirectly (e.g. cyclogenesis Tibaldi et al., 1990), re- lated to the influence of mountain ranges on atmospheric motions. The steep slopes of Printer-friendly Version the Alps and the Apennines in the vicinity of large coastal areas of the Mediterranean, and the sea itself that acts as a large source of moisture and heat, are the key factors Interactive Discussion 11646 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | in determining the convergence and the rapid uplift of moist and unstable air, being re- sponsible for triggering condensation and convective instability processes (Benzi et al., HESSD 1997; Rotunno and Ferretti, 2001). Heavy rainfall events are often associated with the 10, 11643–11710, 2013 development of intense convective systems (Davolio et al., 2009; Melani et al., 2013), 5 whose scientific understanding and