The impact of observations on Mesoscale Model forecasts of three‐hourly rainfall accumulations

Anderson, Serin; Graham, Richard; Bader, M.

doi:10.1017/s1350482700001614

Cited by 7 publications

(6 citation statements)

References 7 publications

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“…Increasing the frequency of the radar data assimilated from 3-hourly to hourly improves the first 6 h of the forecast. One observation impact study (Anderson, 2002) examined forecasts in which observations had given a significant improvement in 6-12 h rainfall forecasts, and investigated the origin of the improvement. Radar data were found to be the most frequent source of the benefit with a similar frequency for other data types such as aircraft and radiosonde.…”

Section: Derived Productsmentioning

confidence: 99%

Satellite cloud and precipitation assimilation at operational NWP centres

Bauer

Auligné

Bell

et al. 2011

Quart J Royal Meteoro Soc

121

100

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The status of current efforts to assimilate cloud-and precipitation-affected satellite data is summarised with special focus on infrared and microwave radiance data obtained from operational Earth observation satellites. All global centres pursue efforts to enhance infrared radiance data usage due to the limited availability of temperature observations in cloudy regions where forecast skill is estimated to strongly depend on the initial conditions. Most systems focus on the sharpening of weighting functions at cloud top providing high vertical resolution temperature increments to the analysis, mainly in areas of persistent high and low cloud cover. Microwave radiance assimilation produces impact on the deeper atmospheric moisture structures as well as cloud microphysics and, through control variable and background-error formulation, also on temperature but to lesser extent than infrared data. Examples of how the impacts of these two observation types are combined are shown for subtropical low-level cloud regimes. The overall impact of assimilating such data on forecast skill is measurably positive despite the fact that the employed assimilation systems have been constructed and optimized for clear-sky data. This leads to the conclusion that a better understanding and modelling of model processes in cloud-affected areas and data assimilation system enhancements through inclusion of moist processes and their error characterization will contribute substantially to future forecast improvement.

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Section: Derived Productsmentioning

confidence: 99%

Satellite cloud and precipitation assimilation at operational NWP centres

Bauer

Auligné

Bell

et al. 2011

Quart J Royal Meteoro Soc

121

100

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“…However, using a similar method of serial casestudies, radiosonde humidity profiles have been found to be very beneficial for shortrange mesoscale model forecasts of rain accumulation (e.g. Anderson et al 1998a).…”

Section: (C) Discussion Of Resultsmentioning

confidence: 99%

The relative utility of current observation systems to global‐scale NWP forecasts

Graham

Anderson

Bader

2000

Quart J Royal Meteoro Soc

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SUMMARYWe study 20 cases in which 60-hour Numerical Weather Prediction (NWP) of specific synoptic events have been markedly improved by observations made during the final 15 hours prior to the forecast initial time. For each case, the observing systems which played major r6les in improving the accuracy of the forecast mean-sea-level pressure (m.s.1.p.) field are identified using a series of Observation System Experiments. The relative utility of each observation type is then assessed according to the frequency, over all cases, with which it delivers a major beneficial impact.The method of multiple case-study employed has the advantage that observation value is assessed according to the benefit delivered to forecasts of events (e.g. cyclogenesis) which are of prime importance to operational meteorology. The method, therefore, provides a useful complement to the conventional statistical approach which typically yields an 'average' benefit, calculated for all regimes (both active and 'quiet') occurring over a given period within a specific geographical region. The cases are selected from the most significant data-impact events detected in routine operational forecasts of m.s.l.p., for Europe and North America, during the period September 1993 to December 1995.Results indicate that, for weather systems developing over North America, radiosonde and aircraft reports contribute major forecast benefits most often, confirming their key r6le in the North American network. These two observing systems contribute with similar frequency, suggesting that the effectiveness of the less abundant radiosonde reports is boosted significantly by their profile format. Surface data and cloud-track winds are the next most frequent contributors.For weather systems developing over the North Pacific and North Atlantic, aircraft winds contribute forecast benefits most frequently, and by a wide margin. Conventional surface data also play a key r6le.Comparison of the utility of wind and temperature data suggests that, on average, the benefit of wind profiles is somewhat greater than that of temperature profiles, and that, in levels above -400 hPa, wind data are considerably more valuable than temperature data.The results give insights which can be used to guide the rationalization of existing networks within the northern hemisphere mid latitudes, and the following recommendations are made with a view to improving NWP over the European area.0 Acquire more aircraft data over North Atlantic routes and over Europe (including reports during climb and descent). However, caution must be exercised if aircraft data are used to replace profile information from radiosondes.0 Deploy more surface observations (e.g. drifting buoys) and shipborne radiosonde ascents over the North Atlantic.0 Make more use of pattern-tracking techniques for deriving 'clear-air' wind data from satellite water-vapour imagery.Continue investigation of the effectiveness of observations 'targeted' on objectively defined regions where model errors are predicted to grow most rapidly.

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“…in hPa, where ρ 0 is in g/m 3 . An approximation of the saturation moist air pressure as a function of temperature profile is given as [17] ( 5 ) in hPa.…”

Section: The Forward Modelmentioning

confidence: 99%

“…In fact, produced [2] by evaporation of warm ocean water, it is redistributed vertically and horizontally across the globe by deep convective cells and large-scale eddies, influencing global circulation models forecasts. Furthermore, in a recent study [3] the moisture field resulted the most beneficial individual observation type for improving the accuracy of forecasts of precipitation accumulation from the UK Met. Office Mesoscale NWP Model.…”

Section: Introductionmentioning

confidence: 99%

PIn. I. An operational nonlinear physical inversion algorithm for precipitable and cloud liquid water estimate in nonraining conditions over sea

Migliorini

Nativi

2001

IEEE Trans. Geosci. Remote Sensing

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An operational nonlinear Physical Inversion (PIn) algorithm for precipitable and cloud liquid water estimate is described. It is suited for a generic conical scanning satellite microwave radiometer acquisitions over sea, in non-raining conditions. The algorithm does not need any calibration phase, and is independent from the availability of in-situ data, being consistent in different geographical and climatological situations. Adopted formulation is addressed to provide observational data to help validating water vapour and cloud fields produced by a numerical weather prediction model. Furthermore, such technique can be utilised for global reanalyses purposes, improving estimates of primary fields of hydrological cycle. A sensitivity study of the forward model and a comparison between output brightness temperatures and those from a robust numerical code are also reported: achieved discrepancies result acceptable with respect to instrumental constrains and computation time. Index Terms-radiative transfer, microwave remote sensing, inversion techniques. I.

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The impact of observations on Mesoscale Model forecasts of three‐hourly rainfall accumulations

Cited by 7 publications

References 7 publications

Satellite cloud and precipitation assimilation at operational NWP centres

Satellite cloud and precipitation assimilation at operational NWP centres

The relative utility of current observation systems to global‐scale NWP forecasts

PIn. I. An operational nonlinear physical inversion algorithm for precipitable and cloud liquid water estimate in nonraining conditions over sea

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