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editorial ECMWF Newsletter No. 128 – Summer 2011 Contents New Director-General Editorial New Director-General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 NEWS C M Y CM CY CMY B C M Y 70% CMY B C M Y MY CMY CMY B C M International . . . . . . . . . +44 118 949 9000 ECMWF website . . . . . . . . . . . . . . http://www.ecmwf.int– B National. . . . . . . . . . . . . . . . 0118 949 9000 CMY . . . . . . . . . . . . . . . . . . . . +44 118 986 9450 70% Fax: Telephone: Y Shinfield Park, Reading, Berkshire RG2 9AX, UK M Contacting ECMWF C 2 Any queries about the content or distribution of the ECMWF Newsletter should be sent to Bob.Riddaway@ecmwf.int Guidance about submitting an article is available at www.ecmwf.int/publications/newsletter/guidance.pdf B 22 Typesetting and Graphics: Rob Hine CMY 21 Editor: Bob Riddaway 70% 20 The ECMWF Newsletter is published quarterly. Its purpose is to make users of ECMWF products, collaborators with ECMWF and the wider meteorological community aware of new developments at ECMWF and the use that can be made of ECMWF products. Most articles are prepared by staff at ECMWF, but articles are also welcome from people working elsewhere, especially those from Member States and Co-operating States. The ECMWF Newsletter is not peer-reviewed. 19 Publication policy 70% Useful names and telephone numbers within ECMWF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1Y4 Index of newsletter articles . . . . . . . . . . . . . . . . . . . . . . . 28 1M4 ECMWF publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1 1C4 ECMWF Calendar 2011. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1B4 General MY Developments in precipitation verification. . . . . . . . . . . . 12 Observation errors and their correlations for satellite radiances. . . . . . . . . . . . . . . . . . 17 Development of cloud condensate background errors. . 23 18 Meteorology On 1 July 2011 I took over from Dominique Marbouty as Director-General of ECMWF. Not least because of the research collaboration I had with ECMWF scientists some years ago, I am fully aware of its deserved reputation for being a world leader in numerical weather prediction (NWP). Indeed my research interests over many years have been related to weather systems, their dynamics and predictability. My background is as a physicist and then for many years as a Professor of Meteorology at the University of Reading. In 1999 I became the Director of the Hadley Centre for climate prediction and research, and subse­ quently the founding Director of the UK’s National Centre for Atmos­ pheric Science. I took up the post of Chief Executive of the UK’s Natural Environ­ment Research Council in 2005, from which role I moved to ECMWF. As a leader I have experience of the many and varied issues that need to be managed effectively and efficiently for organisations both small and large. As the new Director-General I am delighted to be joining such a successful and important organisation as ECMWF. I have greatly enjoyed learning about the activities of ECMWF, and my personal thanks go to Dominique, and others at ECMWF, for making my transition into the role such a smooth one. He involved me as Director-GeneralElect in the most recent meetings of the Policy Advisory Committee and Council, as well as in the final stages of preparation of the ECMWF Strategy 2011–2020. ECMWF and the meteo­ro­logi­cal community owe Dominique a huge debt of gratitude for his outstanding contributions over many years and I wish him well in the future. The President of ECMWF Council, François Jacq, pays further tribute to Dominique on page 2 of this Newsletter. As described in the Strategy, the vision is for ECMWF to be the acknowledged world leader in global medium-range NWP, in order to provide the best possible forecast products, particularly to the European national meteorological services, for the benefit of society. This is an inspirational as well as challenging vision and one that I am fully committed to it being achieved. People all over the world rely on weather forecasts to help them in their daily lives whether it is to avoid problems associated with severe weather or whether it be an opportunity 17 An appreciation of Dominique Marbouty. . . . . . . . . . . . . . 2 Outcome of Council’s 75th session. . . . . . . . . . . . . . . . . . 3 Jean Labrousse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ECMWF Annual Report for 2010 . . . . . . . . . . . . . . . . . . . . 4 Forecast Products Users’ Meeting, June 2011 . . . . . . . . . 5 IMO prize to first ECMWF Director . . . . . . . . . . . . . . . . . . 6 Extension of the ERA-Interim reanalysis to 1979. . . . . . . . 7 Improved exploitation of radio occultation observations. . 8 Representing model uncertainty and error in weather and climate prediction . . . . . . . . . . . . . . . . . . . 9 New model cycle 37r2. . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Y 70% CMY B C NEWS to develop their businesses. Indeed, the way we live has increased our sensitivity and vulnerability to the natural environment and in particular to weather. Being able to give as early foresight as possible of what weather conditions are to come is a huge benefit arising from ECMWF forecast products. Our goal is to develop our core forecasting systems. This will mean that we can produce forecast products that enable people to receive early warnings of severe weather as many days in advance as possible and reliable predictions up to a few weeks ahead of the onset and decay of heat and cold spells as well as periods of drought. As a result national meteo­ro­logical services (NMSs) will be able to use our forecast ECMWF Newsletter No. 128 – Summer 2011 products to provide and develop services to sectors such as the energy supply industry, trans­port, commerce, agriculture, health and disaster relief. In addition, we will be producing forecasts that support the provision of air quality services, for example, for protection of health and developing environmental policies. A further goal is to produce reanalyses that provide the best possible descrip­tion of the past weather and climate trends in the twentieth century. In all these areas the activities of ECMWF and NMSs will continue to be fully complementary. As I start as Director-General I reflect on the fact that ECMWF is a user-driven organisation that is a sig­ nifi­c ant part of the European Meteo­ro­ logical Infra­struc­ture. As well as the crucial operational forecast products that it creates and disseminates, ECMWF is an important component of the meteorological research com­ muni­ty that is focussed on advances to improve forecast skill and capabilities. We collaborate and partner with many individuals and organisations for mutual benefit. During my period as Director-General I am committed to ensuring that ECMWF continues to focus on costefficiency and value-for-money whilst fully serving the needs of the Member and Co-operating States and acting as a beacon to the international meteo­ ro­ logical community in the field of NWP. Alan Thorpe An appreciation of Dominique Marbouty François Jacq (ECMWF President) On 30 June Dominique Marbouty relinquished the post of DirectorGeneral of ECMWF. He will now take up a new job in Paris as an adviser in the French Ministry of Environment from 1 September. During his 12 years at ECMWF, with 7 of those years as its leader, Dominique has made major contributions to the enhancement of the status of ECMWF and the development of its activities to meet the needs of Member States. Before joining ECMWF, Dominique had a long and fruitful career within Météo-France. He held a wide variety of positions: head of a research unit, head of a regional office, head of the regional network and deputy director general. His experience of both research and operations, along with an understanding of the political dimension, were put at the service of ECMWF. Dominique was first recruited at ECMWF as Head of Operations, and then became Director and finally, a few months before leaving, DirectorGeneral. ECMWF is without doubt the leading medium-range forecasting centre in the world. This is of course 2 the result of the effort and competence of the entire staff, but these need to be applied with a clear focus on what needs to be achieved. Dominique, along with his fellow Directors, was instru­mental in defining the appro­ priate strategy for achieving and maintaining world-class status, and ensuring the implementation of that ambitious strategy. The strategy was clearly based on making significant and well-defined scientific progress, particularly aimed at enhancing the early warning of severe weather. But, to support the scientific strategy, it was important to develop ECMWF’s infrastructure. This is why it was so important that Dominique was able to: l Convince Member States to double the budget devoted to high-perform­ ance computing (HPC), which in turn triggered important developments. l Complete the HPC procurement with great efficiency. Research teams also need buildings and infrastructures. Dominique was able to build a new facility devoted to research without any increased funding from Member States, even after the collapse of the firm chosen to build it. This demonstrates his wide range of capabilities. Dominique also had the vision that ECMWF should develop in other directions. For example he convinced Council that ECMWF should coordinate European efforts in global reanalysis. Indeed, the recent start of the ERA-CLIM project, funded by the European Commission, is a culmi­na­ tion of efforts in this area. Also the development of seasonal forecasts has been an important step in supporting the activities of Member States. There is of course another important legacy from Dominique. After major efforts, he succeeded in bringing into force the amended convention – this is a major achievement. It provides a mod­ernized instrument for supporting ECMWF’s activities and will strongly facilitate the further expansion of ECMWF. As impressive as it may be, a scien­ tific centre could not be of world-class without a proper administration and a ECMWF Newsletter No. 128 – Summer 2011 proper human resources policy. In this field also, Dominique has been a big influence. For example, he has been able to: l Solve the issue of the pension scheme by convincing the Council to put in place a mechanism which does not threaten ECMWF’s financial position. l Considerably improve the situation of consultants; though it is still necessary to develop a proper policy on those matters, Dominique has set up the foundations. Good management also means having good quality accounts – so Dominique started the imple­men­tation of IPSAS (International Public Sector Accounting Standards). He also had to face concerns of the Members States about the accuracy of the budget. However (and otherwise it would not be fair on Alan Thorpe), there are still things to be solved. Dominique experienced hard times discussing the conditions under which ECMWF operates. These illustrate that in some cases, politics is even more compli­ca­ ted than understanding the physics of atmosphere. Dominique had been the source of wise guidance in those matters, showing both diplomacy and tenacity. Finally, saying ECMWF is a Euro­ pean institution is not understating the situation, even if European in this case does not mean the European Union. Thanks to Dominique, ECMWF is a major component of the European Meteorological Infrastructure (EMI). For example, Dominique has been able to: NEWS l Establish excellent relationships with EUMETNET, EUMETSAT and ESA. l Ensure ECMWF is highly respected by the European Commission. In particular the contribution of ECMWF to the GMES (Global Monitoring for Environment and Security) programme is impressive. What has been written only outlines Dominique’s profound influence on all aspects of ECMWF’s activities and his achievements during his highly successful period as its leader. He will be greatly missed, but I am sure that Dominique now has a very distin­ guished successor. I am convinced that Alan Thorpe will further enhance ECMWF’s reputation and achieve­ ments by building upon Dominique’s legacy. Outcome of Council’s 75th session Manfred Klöppel Raising of the Icelandic flag. To mark the participation of Iceland in the Council as a Member State the Icelandic flag was raised. From left to right: Árni Snorrason (Director General of the Icelandic Meteorological Office), Alan Thorpe (incoming ECMWF Director-General), Dominique Marbouty (outgoing ECMWF Director-General) and François Jacq (ECMWF President). Under the chairmanship of its President, Francois Jacq (France), the Council held its 75th session on 16 and 17 June 2011. This session was the first chaired by Mr Jacq, the last for the outgoing Director-General, Dominique Marbouty, and the first for Iceland participating as a Member State. During the first day of the session, the representative from Iceland, Árni Snorrason, raised the Icelandic flag. The Council congratulated the Centre on the main achievements since its last session in December 2010, noting in particular that: l A new cycle of the forecasting sys­ tem had been implemented on 18 May 2011, introducing meteorological and technical changes. l Several important projects, in parti­ cular the ERA-CLIM project funded by the European Union, were developing as expected. The following main decisions were taken unanimously at this session: l Member States agreed to vote by correspondence in August 2011 on the accession of the Republic of Croatia to the ECMWF Convention. l The Council authorised the DirectorGeneral to start negotiations with the Republic of Moldova on becoming an ECMWF Co-operating State. l A resolution on the Centre’s contributions to Global Monitoring for Environment and Security (GMES) was adopted requesting the European Union to prepare a framework for the use of the Centre’s facilities in the operational phase from 2014 onwards (see http://www.ecmwf.int/about/ basic/volume-1/resolutions/index.html) and extending the already agreed data policy to cover the GMES pre­opera­ tion­al phase. In addition, the Council unami­ nously adopted the ECMWF Strategy for the period 2011–2020. The principal goal of ECMWF in the next ten years is to improve its global, medium-range weather forecasting systems, at the current rapid rates, in order to: l Provide Member States’ National Meteorological Services with reliable forecasts of severe weather across the medium-range. l Meet Member States’ requirements for high quality near-surface weather forecast products such as precipitation, wind and temperature. Complementary goals are to: l Improve the quality of monthly and seasonal–to-interannual forecasts. 3 NEWS Support climate monitoring with state-of-the-art reanalyses of the Earth-system. l Contribute towards the optimisation of the Global Observing System. l ECMWF Newsletter No. 128 – Summer 2011 Enhance support to Member States’ national forecasting activities by providing suitable boundary conditions for limited-area models. l Deliver global analyses and forecasts of atmospheric composition l The strategy itself and a document describing the scientific and technical basis of the strategy can be found at: l http://www.ecmwf.int/about/ programmatic/strategy/ index.html Jean Labrousse Jean Labrousse, the second Director at ECMWF, sadly passed away on Saturday 9 July 2011. A French national, Jean played an important role during the early days of ECMWF. As Head of Operations, from June 1974 to 1979, he had the overall responsibility for the Centre’s operational forecasting system and for the Centre’s computer system. He was instrumental in establishing the operational facilities required for ECMWF to deliver its first operational global medium-range weather fore­ cast to its Member States on 1 August 1979. Jean Labrousse became ECMWF’s second Director from 1 January 1980. After a short period of two years he returned to France, since he was appointed as Director of Météorologie Nationale (Météo-France) from 1 January 1982 by the French Conseil des Ministres. From 1987 to 1991, he was Director of the Research and Development Programme of the World Meteorological Organization. Before he retired in November 1997, Jean Labrousse was Director of the Earth-Ocean-Space-Environment Department in the French Ministry of Research, Technology and Space (1991–1993), Scientific Secretary for Meteorology EEC/COST (1994–1997), and Head of the French Secretariat for Joint Implementation (United Nations Framework Convention on Climate Change). Staff at ECMWF are enormously grateful for Jean’s outstanding contributions in setting up ECMWF’s first operational infrastructure and for his excellent leadership during his short period as Director of ECMWF. ECMWF Annual Report for 2010 Bob Riddaway 4 The ECMWF Annual Report 2010 has been published. It provides an over­ view and a broad, non-technical description of ECMWF’s main activities. There is also an indication of ECMWF’s future plans. The report draws attention to some of the key events of 2010 that are associated with operational activities and membership of ECMWF. l Implementation of IFS Cycle 36r1. A new cycle of the ECMWF fore­cast­ing and analysis system, Cy36r1, was introduced in operations. This cycle includes major increases in horizontal resolution for the deterministic and the probabilistic forecasting systems. The higher-resolution wind fields are better at representing features such as tropical storms, fronts and land/sea transitions; this translates into better wave forecasts. 26 January l Headline measure of skill reached the forecast range of 10 days. ECMWF reached a landmark in the perform­ ance of its deterministic forecasting system during a month. For the first time ever, the headline measure of skill in February reached the forecast range of 10 days. February l ERA-CLIM project selected for funding. The ERA-CLIM project proposal, submitted to the European Commission in January, was selected for funding. This three-year project will be coordinated by ECMWF. The goal of ERA-CLIM is to prepare for the production of a next-generation global atmospheric reanalysis that spans the entire 20th century. 12 May NEWS ECMWF Newsletter No. 128 – Summer 2011 New products on the website. New products from the ECMWF Ensemble Prediction System (EPS) were made available on the website following Council’s decision to extend the range of weather forecast products that are available freely and with no restrictions. 13 May l Amended ECMWF Convention entered into force. The amendments to the ECMWF Convention entered into force. This is a milestone in ECMWF’s history as it allows an enlarge­ment of ECMWF’s member­ ship and an expansion of the scope of its activities. 6 June l Implementation of IFS Cycle 36r2. A new cycle of the ECMWF forecasting and analysis system, Cy36r2, was implemented. This included a new method for providing initial-time perturbations for the EPS. In the new cycle, differences between members of an ensemble of data assimilations (EDA) were used. 22 June l Co-operation agreement with Bulgaria. The co-operation agreement between the Republic of Bulgaria and ECMWF entered into force. 12 July l Co-operation agreement with Israel. The co-operation agreement between Israel and ECMWF entered into force. 28 October l Implementation of IFS Cycle 36r4. The new model cycle 36r4 was imple­ mented in operations. The new cycle includes a new cloud para­metri­z­ation scheme and new surface analysis schemes introduced for snow and soil moisture. 9 November l Migration of data to the Auto­mated Tape Libraries completed. The process of migrating data from the old silos to the new Automated Tape Libraries finished. 19 December In addition the Annual Report describes a wide range of activities and achievements in 2010 that are of benefit to the operational activities of Member and Co-operating States as well as supporting the endevours of the international meteorological community. Dominique Marbouty, ECMWF Director-General, starts his foreword to the Annual Report by stating that: “The main event of 2010 was undoubt­edly the entry into force of the amended Convention on 6 June. It concluded a process that started more than 10 years ago when the ECMWF Council decided that it wanted to allow new States to join ECMWF. This period was divided in two almost equal phases. The first one was dedicated to defining the necessary l changes and resulted in the unani­ mous adoption of the proposed changes at an extraordinary session of the Council in April 2005. During the second one it was necessary for all Member States to adopt these amend­ ments which, for most of them, required a decision by their Parlia­ ments. By the end of 2010 two States had already officially applied to become ECMWF Member States.” As outgoing President of the Council, Wolfgang Kusch, states that: “ECMWF plays a significant role in complementing the activities of national institutions in Member and Co-operating States, particularly meteorological and hydrological services. During my presidency in 2010, the Centre once again provided very good early forecasts of various severe weather events several days or even weeks ahead, thereby allowing early warnings to the public.” Wolfgang Kusch concluded his statement by stating that “I would like to congratulate the whole team working at ECMWF on the remarkable progress made in a variety of areas during 2010”. The Annual Report can be down­ loaded from: l http://www.ecmwf.int/ publications/annual_report Forecast Products Users’ Meeting, June 2011 David Richardson The annual meeting for users of ECMWF forecast products was held at ECMWF on 8 to 10 June. The purposes of these meetings are to: l Update users on recent and planned developments of the ECMWF operational forecasting system, especially the forecast products. l Give users of ECMWF forecasts the opportunity to discuss their experience with the medium-range and extended-range products and to present feedback on their use and future requirements. The meeting was attended by representatives from National Meteorological Services of 16 Member States and Co-operating States and from a number of commercial users of ECMWF weather forecast products. Changes to the ECMWF forecasting system since the previous meeting, including the implementation of three new operational model cycles, were presented. Cycle 36r4 (November 2010) incorporated a large number of improvements, including a new cloud scheme and new surface analyses for soil moisture and snow depth. Cycle 37r2 (May 2011) included changes to the use of observations (reduced observation errors for AMSU-A satellite data) and use of flowdependent background errors (from the EDA) in the data assimilation. A number of significant changes were made to the Ensemble Prediction System (EPS), including the use of the ensemble of data assimilations (EDA) to provide additional initial perturbations (Cycle 36r2, June 2010) and revised simulation of the model uncertainties in the EPS (Cycle 36r4). ECMWF has introduced a number of new products during the last year. New parameters produced from the forecasts include height of lowest cloud base, height of 0°C level, surface and sub-surface runoff, totalsky and clear-sky direct solar radiation at the surface, and cloud rain and snow water content. Low, medium and high cloud covers are now available from the EPS members as well as for the deterministic 5 NEWS ECMWF Newsletter No. 128 – Summer 2011 forecast. A new set of web pages has been prepared, showing the graphical products from both Thursday and Monday runs. Users confirmed that this reorganisation, which allows users to easily compare the latest forecast with the previous ones for the same verifying period, meets their requirements. A new seasonal forecasting system is planned for implementation later in 2011. This uses a higher resolution and more recent version of the ECMWF atmospheric model coupled to the NEMO ocean model. The new System 4 has significantly lower overall model biases that the current System 3. The implementation The new ecCharts interactive web facility for operational forecasters. Forecasters schedule for System 4 was discussed, can easily zoom and pan to relocate the map to any geographical area of interest. Also they including the availability of the can display a wide range of fields from the deterministic and EPS forecasts. Timeseries and EPSgrams can be displayed by clicking on any point or using the city finder tool. The hindcast datasets for users. Further system has already proved valuable to forecasters, for example during the Fukushima crisis. details, including updates on the implementation and performance of forecast. New products introduced tun­ity to try out the features during the System 4 are available at during the last year include the new meeting. ecCharts has been avail­able to l http://www.ecmwf.int/products/ changes/system4/ EPS clustering (described in detail operational forecasters in the Member As usual, during the meeting partici­ ECMWF Newsletter No. 127), and States and Co-operating States for beta information on tropical cyclone testing since the begin­ning of the year. pants made a number of requests for additional products. These focused on genesis and extra-tropical cyclone Several of the partici­pants reported tracks on the ECMWF web site. Users that ecCharts has already proved to be more weather element information commented positively on these recent a valuable tool; in partic­ular it allowed and extension of some products additions, and several examples of forecasters to gain quick access to full- further into the medium range. The presentations and summary their use were shown during the resolution data for the Japan region from the meeting are available on the presentations from users. during the Fukushima crisis. ECMWF website: The new interactive web facility ECMWF is introducing a second l http://www.ecmwf.int/newsevents/ aimed at forecasters (ecCharts, see weekly run of the monthly forecast, meetings/forecast_products_user/ ECMWF Newsletter No. 126) was run every Monday (00 UTC), to provide Presentations2011/ presented and users had the oppor­ an update to the current Thursday IMO prize to first ECMWF Director Alan Thorpe WMO’s most prestigious award, the IMO prize, originates from WMO’s predecessor, the International Meteorological Organization. It is granted annually by the WMO Executive Council for outstanding work in the field of meteorology, climatology, hydrology and related science. The 56th IMO prize has been awarded to the late Aksel WiinNielsen as a lifetime achievement award. Prof Wiin-Nielsen, who passed 6 away last year, was particularly renown for his leadership and success in setting up ECMWF. A Danish national, Prof Wiin-Nielsen was ECMWF’s first Director from I January 1974 to 31 December 1979. He put ECMWF on track to become a world leader in global Numerical Weather Prediction (NWP). Before joining ECMWF, Prof WiinNielsen developed a scientific career that started in 1952 in the University of Copenhagen, and continued in Stockholm at the International Meteorological Institute set up by NEWS ECMWF Newsletter No. 128 – Summer 2011 Carl-Gustaf Rossby. Here he took part in setting up the first operational NWP system in the world. Prof Wiin-Nielsen moved to the USA in 1959 where he worked at the Joint Numerical Weather Prediction Unit and NCAR. From 1963 he created the Department of Meteorology at the University of Michigan. When a decision was made to establish ECMWF, Prof Wiin-Nielsen was the natural choice as its first Director. On leaving ECMWF he became WMO Secretary-General in 1980, and then Director of the Danish Meteo­ro­ logical Institute (DMI) in 1984. In that function, Prof Wiin-Nielsen returned to ECMWF to attend sessions of the ECMWF Council, representing Denmark. He served as President of the ECMWF Council in 1987. Prof Wiin-Nielsen was one of the leading meteorologists of the second part of the twentieth century who contributed significantly to the development and understanding of NWP. Extension of the ERA-Interim reanalysis to 1979 Dick Dee, Paul Poli, Adrian Simmons In response to demands from many users, the ERA-Interim reanalysis dataset has been extended by a decade and now includes data from 1 January 1979 to the present. This extension makes the dataset even more useful for climate-related studies and climate change monitoring, as it now covers a period exceeding three decades. The 10-year extension was comple­ ted in just under 8 months with few technical interruptions. Most importantly, the accuracy of the reanalysed fields is not very differ­ent in the first decade compared to the 1990s, and the temporal consist­ency of the extended reanaly­ sis is remarkably good. This can be seen, for example, in time series of observation departures, and also in the bias correct­ions of satellite radiance data that are automatically generated during the reanalysis. Producing a long reanalysis in multiple streams has always been a challenge, but this (unplanned) exercise with ERA-Interim has demonstrated that it is possible to do so without introducing major jumps or shifts in the final product. ERA-Interim data for 1979–1988 will shortly be available in MARS and on the ECMWF public data server. We will continue to extend the ERAInterim reanalysis forward in time for at least several more years, until it can be replaced by a new version that uses an up-to-date IFS release and an improved set of input observations. This will be done in the framework of the ERA-CLIM project (see ECMWF Newsletter No. 123, p.6); current plans are to begin production of such a new reanalysis of the satellite era by the end of 2012. Global mean background departures from radiosonde temperature observations (275–775hPa) 0.5 0 –0.5 1982 1986 1990 1994 1998 2002 2006 2010 2006 2010 2006 2010 Global mean background departures for MSU channel 2 radiance observations 0.5 0 –0.5 0.6 0.3 0 –0.3 –0.6 –0.9 –1.2 1982 1986 1990 1994 1998 2002 Global mean bias correction for MSU channel 2 radiance observations 1982 1986 1990 1994 1998 2002 Stability and temporal consistency of the extended ERA-Interim reanalysis. The three panels demonstrate the stability and temporal consistency of the extended ERA-Interim reanalysis, and the nearly seamless transition between the two production streams on 1 January 1989. Reanalysed temperatures in the mid-troposphere are largely consistent with radiosonde observations (top panel) and with bias-corrected radiance measurements from the Microwave Sounding Units (MSU) flown on successive NOAA satellites (centre panel; colours indicate different satellites). The bias corrections for the MSU data, produced by the variational analysis in ERA-Interim, account for calibration differences, orbital drifts and various other instrument errors (lower panel). 7 NEWS ECMWF Newsletter No. 128 – Summer 2011 Improved exploitation of radio occultation observations Axel von Engeln (EUMETSAT, Darmstadt, Germany), David R. Ector (NOAA, Boulder, Colorado, USA) Radio occultation measurements (RO) are now an important component of the Global Observing System. In June 2008, the joint ECMWF/GRAS Satellite Application Facility (GRAS SAF) work­ shop on ‘The Applications of GPS Radio Occultation Measurements’, recommended the formation of an International Radio Occultation Work­ ing Group (IROWG). In 2009, this was endorsed by the Coordinating Group for Meteorological Satellites (CGMS), and IROWG is now the fourth perma­ nent working group of the CGMS. The group’s first meeting (IROWG-1) took place on 10–11 September, 2010, at the University of Graz, Austria. More than sixty scientists participated in IROWG-1, including representatives from the major centres providing and assimilating RO data. IROWG-1 was Working Groups of the Coordinating Group for Meteorological Satellites (CGMS) The CGMS Working Groups are: l International Radio Occultations Working Group (IROWG) l International TOVS Working Group (ITWG) (meetings are known as International TOVS Study Conferences) l International Winds Working Group (IWWG) l International Precipitation Working Group (IPWG) The working groups interact closely with the annual CGMS meetings by reporting to and taking actions and recommend­ ations from CGMS. The regular and formal interaction provides a direct link with the operational agencies that operate the relevant satellite instruments. 8 held together with the ‘International Workshop on Occultations for Probing Atmosphere and Climate 2010’ (OPAC 2010) and the ‘GRAS SAF Climate Workshop’, 6–10 September. The RO technique itself uses observa­tions of Global Positioning System (GPS) signals seen through the Earth’s atmosphere from a space-based GPS receiver; it has been improv­ing our understanding and prediction of the weather, climate and ionosphere over the last fifteen years. RO missions such as GPS-MET, CHAMP, SAC-C, Oersted, GRACE, GRAS, IOX, CORISS and the RO constellation, COSMIC, have been used as important observa­ tion sources for NWP models, climate benchmarking reference and iono­ spheric assimilation models. Several of the existing RO satellites have reached or are nearing the end of their useful lifetimes. Recent missions are TerraSAR-X/ TanDEM-X and ROSA on Oceansat-2; some follow-on RO satellite systems are being planned such as COSMIC-2, ROSA/SAC-D, and PAZ. However, it is clear that an international coordi­ nation of efforts is needed in order to: l Understand and utilize more fully RO observations. l Achieve better coverage. l Avoid gaps in the observation systems. l Ensure and sustain RO observations. Furthermore, within the next two decades there will be a multiplicity of Global Navigation Satellite Systems (GNSS) constellations transmitting radio signals which can be used for RO, such as GPS (USA), Galileo (EU), GLONASS (Russian Federation), COMPASS (China), IRNSS (India), and QZSS (Japan). These GNSS will significantly increase the potential number of signal sources for RO to somewhere in the range of 87–125 transmitters, thus providing RO Objectives of the IROWG The overall objectives of IROWG are to: l Make recommendations to national and international agencies and to the atmospheric sounding community regarding the utilis­ ation of current RO data and the development of future RO systems. l Suggest and promote studies aiming at the definition of future RO satellite constellations that fulfill the expected operational and research user requirements. l Encourage cooperation on ground support infrastructure for RO systems. l Promote standard operational procedures and common software to the scientific community for processing and assimilating radio occultation measurements from satellites. l Stimulate increased inter­ national scientific research and development in this field and establish routine means of exchanging scientific studies and verification results. l Support and stimulate the training and education of the scientific community at large for the exploitation of RO product information. l Promote the exploitation of RO observations and their unique capability in the context of climate applications. l Foster communication between the RO scientific community, space agencies and science policy institutions such as the IPCC. opportunities to increase substantially the spatial and temporal sampling densities of the atmosphere and the accuracy of the observations. The main purposes of the IROWG-1 workshop were to exchange experi­ NEWS ECMWF Newsletter No. 128 – Summer 2011 ences in the exploitation of RO data and formulate common recommenda­tions. To achieve this, the Workshop focused on five topics: NWP, climate, research to operations/payload technology, innovative occultation techniques, and space weather. Extensive recommend­ ations and their rationale were devel­ oped for (a) each topic and (b) the entire IROWG and its participating agencies, institutions and providers and assimilators of RO data. Specific aspects regarding the operation and planning of satellite radio occultation instruments were formulated as recommendations to the CGMS. The IROWG-1 Workshop summary and the full recommend­ations are online at the Working Group site l http://www.irowg.org. The next IROWG workshop is in Estes Park, Colorado, USA from 28 March to 3 April 2012. It will be held together with the UCAR/COSMIC Workshop on GPS RO Data Processing for Climate Applications. Further details can be found at the IROWG website. The establishment of the IROWG and its contribution to the improved exploitation of radio occultation observations highlights the value of ECMWF’s programme of workshops. Representing model uncertainty and error in weather and climate prediction Tim Palmer Between 20 and 24 June, a workshop was held at ECMWF on ‘Representing Model Uncertainty and Error in Weather and Climate Prediction’. The workshop attracted almost 100 partici­pants, from Europe and other parts of the world, such as Japan, North and South America and Australia, and was co-sponsored by WMO/ WGNE, WMO/THORPEX, WCRP, and of course ECMWF. The organisers were Tim Palmer (ECMWF/Oxford), Christian Jacob (Monash University), Tom Hamill (NOAA/ESRL), Istvan Szunyogh (Texas A&M) and Ben Kirtman (University of Florida). One of the key highlights of the new ECMWF strategy is provision of reliable medium-range forecasts of severe weather. However, severe weather events can also be some of the most unpredictable. Hence, in order to provide reliable forecasts of severe weather, ECMWF must provide accurate flow-dependent estimates of forecast uncertainty arising from the fact that neither the forecast initial conditions, nor the forecast model equations, are known precisely. This can be achieved within ensemble prediction systems, where both the initial conditions and the model equations are perturbed. There are a number of techniques to represent model uncertainty in ensemble forecasts. These range from the multi-model techniques which feature prominently in IPCC assess­ ment reports, to the stochastic parametrization approach pioneered at ECMWF, but now widely used at weather forecast centres around the world. The multi-model technique is now fairly mature for climate predic­ tion, and clearly outperforms single model predictions. On the other hand, as the TIGGE (THORPEX Interactive Grand Global Ensemble) data shows, there is not much advantage to the multi-model ensemble over the ECMWF EPS (Ensemble Prediction System) in the medium range, especially when hindcast data is used for calibration. The purpose of the meeting was partly to compare different methods for representing model uncertainty, and to discuss how to advance this area of research. Amongst the talks, there were presentations from experts focussing on uncertainty in the representation of specific key processes: this included the dynamical core, cloud microphysics, radiation, convection, oceans and the land surface. There then followed some talks looking at model uncertainty from a mathe­ matical and dynamical systems perspective, including mathematical issues related to the solution of stoch­ astic differential equations. The various schemes used in weather and climate centres to represent uncertainty were reviewed, from the multi-model ensemble, the multiparametrization ensemble, the perturbed parameter approach, the superparametrization approach, and finally the stochastic parametrization 9 NEWS approach. Work describing the use of simplified stochastic dynamical system models for the subgrid­scale, using lattice and cellular automaton dynamics, were presented. It was recognised that in many areas, this is a relatively new and exciting area of research. A key out­ come of the meeting was that the ECMWF Newsletter No. 128 – Summer 2011 stochastic parametrization paradigm needs further development at the process level, and hence needs to be incorporated as part of general parametrization development. Key tools will include sophisticated analyses of observational datasets, output from cloud resolving models, and analyses from objective data assimilation. Data assimilation techniques themselves will benefit from better representations of model uncertainty. The presentations delivered at the workshop, along with the posters, can be found at: l http://www.ecmwf.int/newsevents/ meetings/workshops/2011/ Model_uncertainty/index.html New model cycle 37r2 Peter Bauer, Erik Andersson On 18 May 2011, a new cycle of the Integrated Forecasting System (IFS) was implemented that produced a remarkable improvement over the previous version (cycle 36r4 implemented on 9 November 2010). Cycle 37r2 combined a number of significant scientific contributions with the instalment of GRIB-2 that permits the encoding of data on a larger number of model levels as required by the increased vertical resolution planned for 2012 The scientific components of the Cy37r2 cycle enhanced the accuracy of both the analysis system and forecast model. The ensemble of data assimilations (EDA, ECMWF Newsletter No. 123) produces short-range forecast error variances so that the 4D-Var analysis can better represent the background error dependence on the flow since the introduction of Cy37r2. Since Cy36r2 (implemented on 24 June 2010), the EDA spread has been contributing to the definition of initial perturbations for the EPS, and it is 10 planned to exploit more of the entire EDA error covariance structures in 4D-Var in the near future. The other major contribution to the cycle’s forecast impact is the reduction of AMSU-A radiance observation errors. This followed a comprehensive investigation of spatial and spectral error covariances (see the article starting on page 14) aimed at revising the radiance data thinning to use more of the available data. Since reducing the degree of data thinning increases computational cost, observation errors were reduced instead with very similar effect as produced by less data thinning. With Cy36r4, a new cloud scheme was introduced that added liquid and frozen precipitation as prognostic variables that greatly enhanced the realism and complexity of cloud and precipitation forming processes. This scheme was updated with Cy37r2 so that a condensation limiter was reactivated and several adjustments were made to auto-conversion and melting. The figure shows the summary score card of the cycle. Symbols and colours indicate better (green) or worse (red) performance of Cy37r2 when compared to Cy36r4 as a function of forecast range, both verified with their own analyses. Information on statistical significance has been included as well. The overall performance of Cy37r2 is very good and improvements are statistically significant well into the medium range and, to a different degree, valid at most levels. Satellite data generally dominates the analysis in the southern hemisphere because of the sparse conventional network. Thus, the impact of the new cycle is slightly larger in the southern hemisphere than in other areas due to the increased weight given to AMSU-A data in the analysis; this is a result of reduced observation errors as well as enhanced spatial detail through more flow-dependent background error variances. The apparently negative impact in terms of root-mean-square errors for relative humidity at 700 hPa are explained by the effect of the cloud parametrization change on mean state – anomaly correlation is not affected.