In April 2010, developers representing each of the major reanalysis centers met at Goddard Space Flight Center to discuss technical issues - system advances and lessons learned - associated with recent and ongoing atmospheric reanalyses and plans for the future. The meeting included overviews of each center s development efforts, a discussion of the issues in observations, models and data assimilation, and, finally, identification of priorities for future directions and potential areas of collaboration. This report summarizes the deliberations and recommendations from the meeting as well as some advances since the workshop.

The NCEP Climate Forecast System Reanalysis (CFSR) was completed for the 31-yr period from 1979 to 2009, in January 2010. The CFSR was designed and executed as a global, high-resolution coupled atmosphere–ocean–land surface–sea ice system to provide the best estimate of the state of these coupled domains over this period. The current CFSR will be extended as an operational, real-time product into the future. New features of the CFSR include 1) coupling of the atmosphere and ocean during the generation of the 6-h guess field, 2) an interactive sea ice model, and 3) assimilation of satellite radiances by the Gridpoint Statistical Interpolation (GSI) scheme over the entire period. The CFSR global atmosphere resolution is ~38 km (T382) with 64 levels extending from the surface to 0.26 hPa. The global ocean's latitudinal spacing is 0.25° at the equator, extending to a global 0.5° beyond the tropics, with 40 levels to a depth of 4737 m. The global land surface model has four soil levels and the global sea ice m...

Fred Sanders' career extended over 55 yr, touching upon many of the revolutionary transformations in the field of meteorology during that period. In this paper, his contributions to the transformation of synoptic meteorology, his research into the nature of explosive cyclogenesis, and related advances in the ability to predict these storms are reviewed. In addition to this review, the current status of forecasting oceanic cyclones 4.5 days in advance is presented, illustrating the progress that has been made and the challenges that persist, especially for forecasting those extreme extratropical cyclones that are marked by surface wind speeds exceeding hurricane force. Last, Fred Sanders' participation in a forecast for the historic 1947 snowstorm (that produced snowfall amounts in the New York City area that set records at that time) is reviewed along with an attempt to use today's operational global model to simulate this storm using data that were available at the time. The study reveals the predictive limitations involved with this case based on the scarcity of upper-air data in 1947, while confirming Fred Sanders' forecasting skills when dealing with these types of major storm events, even as a young aviation forecaster at New York's LaGuardia Airport.

The goal of the Southeast Bering Sea Carrying Capacity (SEBSCC) program is to document the role of juvenile pollock in the eastern Bering Sea ecosystem. This includes examination of factors that affect their survival and development and testing of annual indices of pre-recruit (age-1) abundance (from the SEBSCC Concept Paper, July 1995). Within this framework, the purpose of the Indices Working Group (IWG, which was developed at the SEBSCC Principal Investigators meeting held in January 2001) is as follows. Based on the best understanding of ecosystem dynamics, identify potential single-or multi-parameter constructs or indices (e.g., wind mixing, time of spring bloom, etc.) that lead to development of survival indices for pollock in the egg, larval and young of the year life history stages. This information will provide input to the National Marine Fisheries Service (NMFS) stock assessment model and/or models of juvenile pollock for use by fisheries scientists at the Alaska Fisheries Science Center (AFSC)/NMFS. As noted by Napp et al (2000) pollock is the most abundant species harvested in the Bering Sea, accounting for > 65% of the total groundfish biomass and during the 1980s when their total biomass exceeded 20 million tones. The biomass trends of three major trophic guilds in the eastern Bering Sea (1979 to 1998: Schumacher et al., in press) show that while the total biomass of pollock in the 1990s is less than in the 1980s, they still dominate biomass in any of the guilds which include marine birds, mammals, other fishes and crabs. Walleye pollock is a nodal species in the food web (NRC Report, 1996) with juveniles being the It is natural that that pollock have been the focus of the Coastal Ocean Program's SEBSECC. The choice of developing a survival index for the early life history stages (eggs through young of the year) allows an early forecast of potential recruitment to the fishery and a metric that can be compared to existing time series of age-1 abundance (Figure 1). A switch model was developed for the eastern Bering Sea (Megrey et al., 1996), which identifies candidates for causing mortality by life history stage and the mortality variability of each stage indicating the stage contributing the most variability in recruitment to the fishery is set (Figure 2). In this model, transport and turbulence have their greatest impact on mortality of yoke-sack through feeding larval stages. It is the vertical structure of temperature, …

Editor's note: This article is accompanied by a CD-ROM that contains the complete documentation of the NCEP-NCAR Reanalysis and all of the data analyses and forecasts. It is provided to members through the sponsorship of SAIC and GSC.

The impact of satellite data on atmospheric analysis was examined using the NCEP/NCAR reanalysis system. Focus was placed on satellite temperature retrievals, cloud motion vectors, sea surface temperature (SST) analysis and direct use of radiances. Several experimental one-month analyses were produced and compared with the corresponding control analyses. The satellite data was very important for analyses over extreme data sparse areas over eastern Oceans in the Southern Hemisphere and in the stratosphere. Fortunately, current analysis systems effectively utilized available observations so that reasonably accurate analyses could be obtained in most of the Southern Hemisphere without satellite data. It was found that the impact of SST analysis on the atmospheric analysis was significant in the tropics. The difference in the SST produced difference in the precipitation in the forecast. The change in the initial guess divergent circulation associated with the changes in precipitation was large enough to impact the resulting analysis of winds as well as temperature. Finally, the use of radiance in the analysis has a very large impact on the analysis. The radiance analysis tends to enhance horizontal temperature gradients and disturbance intensity where other observationsare not available.

The NCEP and NCAR are cooperating in a project (denoted ''reanalysis'') to produce a 40-year record of global analyses of atmospheric fields in support of the needs of the research and climate monitoring communities. This effort involves the recovery of land surface, ship, rawinsonde, pibal, aircraft, satellite, and other data; quality controlling and assimilating these data with a data assimilation system that is kept unchanged over the reanalysis period 1957-96. This eliminates perceived climate jumps associated with changes in the data assimilation system.The NCEP/NCAR 40-yr reanalysis uses a frozen state-of-the-art global data assimilation system and a database as complete as possible. The data assimilation and the model used are identical to the global system implemented operationally at the NCEP on 11 January 1995, except that the horizontal resolution is T62 (about 210 km). The database has been enhanced with many sources of observations not available in real time for operations, provided by different countries and organizations. The system has been designed with advanced quality control and monitoring components, and can produce 1 mon of reanalysis per day on a Gray YMP/8 supercomputer. Different types of output archives are being created to satisfy different user needs, including a ''quick look'' CD-ROM (one per year) with six tropospheric and stratospheric fields available twice daily, as well as surface, top-of-the atmosphere, and isentropic fields. Reanalysis information and selected output is also available on-line via the Internet (http//:nic.fb4.noaa.gov:8000). A special CDROM, containing 13 years of selected observed, daily, monthly, and climatological data from the NCEP/NCAR Reanalysis, is included with this issue. Output variables are classified into four classes, depending on the degree to which they are influenced by the observations and/or the model. For example, ''C'' variables (such as precipitation and surface fluxes) are completely determined by the model during the data assimilation and should be used with caution. Nevertheless, a comparison of these variables with observations and with several climatologies shows that they generally contain considerable useful information. Eight-day forecasts, produced every 5 days, should be useful for predictability studies and for monitoring the quality of the observing systems.The 40 years of reanalysis (1957-96) should be completed in early 1997. A continuation into the future through an identical Climate Data Assimilation System will allow researchers to reliably compare recent anomalies with those in earlier decades. Since changes in the observing systems will inevitably produce perceived changes in the climate, parallel reanalyses (at least 1 year long) will be generated for the periods immediately after the introduction of new observing systems, such as new types of satellite data.NCEP plans currently call for an updated reanalysis using a state-of-the-art system every five years or so. The successive reanalyses will be greatly facilitated by the generation of the comprehensive database in the present reanalysis.