2 nd International IPWG Workshop Monterey, CA, October, 2004 The International Precipitation Working Group Arnold Gruber – NOAA/NESDIS, Camp Springs, MD, USA and Vincenzo Levizzani – CNR/ISAC, Bologna, Italy

2 nd International IPWG Workshop Monterey, CA, October, 2004 International Precipitation Working Group (IPWG) Established June Workshop at CSU Tamasag Conference Facility, Fort Collins, Colorado, USA Objectives : 1) to promote standard operational procedures and common software for deriving precipitation measurements from satellites; 2) to establish standards for validation and independent verification of precipitation measurements derived from satellite data; including: reference standards for the validation of precipitation for weather, hydrometeorological and climate applications; standard analysis techniques that quantify the uncertainty of ground-based measurements over relevant time and space scales needed by satellite products; 3) to devise and implement regular procedures for the exchange of data on inter-comparisons of operational precipitation measurements from satellites;

2 nd International IPWG Workshop Monterey, CA, October, 2004 Objectives of the IPWG: 4) to stimulate increased international scientific research and development in this field and to establish routine means of exchanging scientific results and verification results; 5) to make recommendations to national and international agencies regarding the utilization of current and future satellite instruments on both polar and geostationary platforms; and 6) to encourage regular education and training activities with the goal of improving global utilization of remote sensing data for precipitation measurements.

2 nd International IPWG Workshop Monterey, CA, October, 2004 First Meeting of IPWG – Madrid Spain, September 23-27, 2002 Three Working Groups – Operational Applications, Research and Validation Total of 21 Recommendations- –Associated actions - a mix of short and long term. –It was ambitious – but sets the stage for future IPWG activities –They should be reviewed by Working Groups and refined with the benefit of two years experience

2 nd International IPWG Workshop Monterey, CA, October, 2004 Some Accomplishments A web page designed for the precipitation community –Reports, Algorithms, Datasets, Validation, Training, Meetings, etc Requirements for MW and sub-mm frequencies protection-Bizzaro Bizzarri Climate Monitoring principles - Phil Arkin

2 nd International IPWG Workshop Monterey, CA, October, 2004 Accomplishments, cont’d Links to validation –AMSRE Validation network- Witek Krajewski –Forecast verification-issues, methods- Beth Ebert –QPF – validation NWP rain-tools – Beth Ebert –Satellite validation rainfall –Beth Ebert –SRDC – Mark Morrissey Links to Training –CGMS Virtual Lab for Education and training –CIRA –Web based resource site for modelers, algorithm developers and users of passive MW data – Grant Petty Co-sponsorship with GPCP of assessment of global precipitation Algorithm Inventory and downloadable algorithms

2 nd International IPWG Workshop Monterey, CA, October, 2004 Inventory of routinely produced precipitation estimates either operational or experimental/research. Results on the IPWG web site: IR-based5 Multiple blend7 MW-based5 MW-IR blended5 EURAINSAT/A 1.0EURAINSAT/A 1.0 – available for downloading- ( 12 requests )

2 nd International IPWG Workshop Monterey, CA, October, 2004 IPWG/GPCP validation / intercomparison project. Validation of daily precipitation from a variety of algorithms: IR, MW, IR/MW, multi-spectral and NWP Beth Ebert - Australia John Janowiak – USA Chris Kidd – Europe Precipitation Validation

2 nd International IPWG Workshop Monterey, CA, October, 2004

2 nd International IPWG Workshop Monterey, CA, October, 2004 Working Group Recommendations

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 1: Form a subgroup for the development of instantaneous precipitation estimation export algorithms for users of geostationary and low Earth-orbiting satellite data. Recommendation 2: Establish the IPWG web site Operational Applications

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 3: Coordinate efforts and activities contemplating the use of satellite precipitation data for "non-traditional" e.g. snow models, irrigation models, pest and disease models, mud slide and avalanche models, dispersion models, surface pollution models and other applications. Recommendation 4: Make case study satellite datasets available through the IPWG website, for further algorithm research. Recommendation 5: Encourage continued development, refinement, and validation of the various research-status satellite sensor precipitation estimation techniques Recommendation 6: Coordinate satellite-based precipitation estimation research with the needs and requirements for climatological applications. Operational Applications

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 1: Provide a generally accessible platform on data and algorithms for the research community. Recommendation 2: Enable co-operation and training through software libraries. Recommendation 3: Develop new strategies on flexible and global structures for physical algorithm development, validation, and data fusion. Establishing a framework for Physical algorithm development (global and regional). Developing a testbed for algorithm validation (comparison data sets etc.). Product merging and blending Research Activities

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 4: Develop different types of analysis/retrieval approaches to solve the principal problem of under-constrained precipitation retrievals. The usefulness and complexity of the needed methodology and information depends on the application. Only by stronger constraints on algorithms can special retrieval problems be solved such as: orographic precipitation, light precipitation, frozen precipitation, resolution enhancement [spatial (vertical/horizontal) and temporal]. Recommendation 5: In view of future sensor development a long-term strategy for frequency protection has to be developed and integrated in the current ITWG activities. Research Activities

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 1: Provide baseline validation standards for satellite precipitation algorithm(s) in terms of the needs of users in NWP data assimilation, nowcasting, hydrology, climate, and algorithm development communities. Recommendation 2: Ensure that members of the NWP data assimilation, nowcasting, hydrology, climate communities are represented at future IPWG meetings. Recommendation 3: Monitor performance of operational precipitation algorithms on a large scale on a daily basis, preferably in connection with NWP forecast validation. Recommendation 4: Support alternative approaches to error estimation such as physical error modeling and cloud/system classification to obtain global error estimates. Validation Activities

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 5: Create an inventory of existing high quality reference data. Recommendation 6: Encourage sharing of data from Intensive Observation Periods in large-scale experiments with the IPWG community, to enable improved validation of satellite rainfall estimates. Recommendation 7: Perform and develop new methods for the error characterization of reference datasets. Validation Activities

2 nd International IPWG Workshop Monterey, CA, October, 2004 Recommendation 8: Encourage the use of dual-gauge systems and optimal network design in operational rain gauge networks, to improve the reliability and quality of rainfall observations. Recommendation 9: Investigate the quality and availability of surface reference networks for the validation of hard-to-measure (orographic, light, solid) precipitation. Recommendation 10: Develop an assessment software package, incorporating both basic and advanced techniques, to facilitate validation of satellite rainfall estimates by algorithm developers and users. Validation Activities