Doppler lidar technology has advanced to the point where wind measurements can be made with confidence from space, thus filling a major gap in the global observing system.

A global three‐dimensional ozone data assimilation system has been developed at the Data Assimilation Office of the NASA Goddard Space Flight Center. The Total Ozone Mapping Spectrometer (TOMS) total ozone data and the Solar Backscatter Ultraviolet/2 (SBUV/2) partial ozone profile observations are assimilated. The assimilation, into an off‐line ozone transport model, is done using the global Physical‐space Statistical Analysis Scheme. This system became operational in December 1999. A detailed description of the statistical analysis scheme and, in particular, of the forecast‐ and observation‐error covariance models is given. A new global anisotropic horizontal forecast‐error correlation model accounts for a varying distribution of observations with latitude. Correlations are largest in the zonal direction in the tropics where data are sparse. Forecast‐error variance is assumed to be proportional to the ozone field. The forecast‐error covariance parameters were determined by maximum‐likelihood estimation. The error covariance models are validated using χ2 statistics. The analysed ozone fields in the winter 1992 are validated against independent observations from ozone sondes and the Halogen Occultation Experiment (HALOE). The difference between the mean HALOE observations and the analysis fields is less than 10% at pressure levels between 70 and 0.2 hPa. The global root‐mean‐square difference between TOMS observed and forecast values is less than 4%. The global root‐mean‐square difference between SBUV observed and analysed ozone between 50 and 3 hPa is less than 15%.

Test beds have become an integral part of the weather enterprise, bridging research and forecast services by transitioning innovative tools and tested methods that impact forecasts and forecast users. O ver roughly the last decade, a variety of "test beds" have come into existence focused on high-impact weather and the core tools of meteorology-observations, models, and fundamental understanding of the underlying physical processes. They have entered the proverbial "valley of death" between research and forecast operations (NAS 2000), Develop and introduce new ideas, data, etc. Input Revise and iterate Experiment and demonstrate End testing Output Test and refine loop V Assess impacts and evaluate and have survived. This paper provides a brief background on how this happened; summarizes test bed origins, methods, and selected accomplishments; and provides a perspective on the future of test beds in our field. Dabbert et al. (2005) provides a useful description of test beds from early in their development and Fig.

Abstract-Wind products from geostationary satellites have been generated for over 20 years and are now used in numerical weather prediction systems. However, geostationary satellites are of limited utility poleward of the midlatitudes. This study demonstrates the feasibility of deriving high latitude tropospheric wind information from polar-orbiting satellites. The methodology employed is based on the algorithms currently used with geostationary satellites, modified for use with the Moderate-Resolution Imaging Spectroradiometer (MODIS) infrared window and water vapor bands. These bands provide wind information throughout the troposphere in both clear and cloudy conditions. The project presents some unique challenges, including the irregularity of temporal sampling, varying viewing geometries, and uncertainties in wind vector height assignment as a result of low atmospheric water vapor amounts and thin clouds. A 30-day case study dataset has been produced and is being used in model impact studies. Preliminary results are encouraging: when the MODIS winds are assimilated in the European Centre for Medium Range Weather Forecasts (ECMWF) system and the NASA Data Assimilation Office system, forecasts of the geopotential height for the Arctic, the Northern Hemisphere extratropics, and the Antarctic are improved significantly.