On the quality of RS41 radiosonde descent data

Abstract. Radiosonde descent profiles have been available from tens of stations for several years now – mainly from Vaisala RS41 radiosondes. They have been compared with the ascent profiles, with ECMWF short-range forecasts and with co-located radio occultation retrievals. Over this time, our understanding of the data has grown, and the comparison has also shed some light on radiosonde ascent data. The fall rate is very variable and is an important factor, with high fall rates being associated with temperature biases, especially at higher altitudes. Ascent winds are affected by pendulum motion; on average, descent winds are less affected by pendulum motion and are smoother. It is plausible that the true wind variability in the vertical lies between that shown by ascent and descent profiles. This discrepancy indicates the need for reference wind measurements. With current processing, the best results are for radiosondes with parachutes and pressure sensors. Some of the wind, temperature and humidity data are now assimilated in the ECMWF forecast system.

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On the quality of RS41 radiosonde descent data

10.5194/amt-2021-183 ◽

2021 ◽

Author(s):

Bruce Ingleby ◽

Martin Motl ◽

Graeme Marlton ◽

David Edwards ◽

Michael Sommer ◽

...

Keyword(s):

Short Range ◽

Radio Occultation ◽

Fall Rate ◽

Pendulum Motion ◽

Descent Data ◽

Wind Variability ◽

Wind Measurements ◽

Fall Rates ◽

Radiosonde Ascent

Abstract. Radiosonde descent profiles have been available from tens of stations for several years now – mainly from Vaisala RS41 radiosondes. They have been compared with the ascent profiles, with ECMWF short-range forecasts and with co-located radio-occultation retrievals. Over this time our understanding of the data has grown, and the comparison also shed some light on radiosonde ascent data. It has become clear that the fall rate is very variable and that it is an important factor, with high fall rates being associated with temperature biases, especially at higher altitudes. Ascent winds are affected by pendulum motion, on average descent winds are less affected by pendulum motion and are smoother. It is plausible that the true wind variability in the vertical lies between that shown by ascent and descent profiles. The discrepancy indicates the need for reference wind measurements.

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Intensidade do vento de dois ciclones tropicais obtida por diferentes conjuntos de dados

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v13.1.p067-075 ◽

2020 ◽

Vol 13 (1) ◽

pp. 067

Author(s):

Christie Andre Souza ◽

Michelle Simões Reboita

Keyword(s):

Tropical Cyclones ◽

The Other ◽

Data Sets ◽

Global Forecast System ◽

Forecast System ◽

Wind Intensity

Os ciclones tropicais quando atingem ventos com intensidade igual ou superior a 119 km/h desenvolvem uma estrutura conhecida como olho em seu centro. Já os ventos mais intensos do sistema são encontrados imediatamente após o olho. Num estudo recente para os ciclones Haiyan e Haima foi levantada a questão da qualidade dos dados do Global Forecast System (GFS) em representar os ventos uma vez que os ventos máximos apareceram no olho do sistema. Diante disso, esse estudo tem como objetivo avaliar como diferentes conjuntos de dados (GFS, ERA5, ERA-Interim e CCMP) representam os ventos nesses dois ciclones tropicais. A ERA5 e o GFS mostram ventos mais intensos nos ciclones do que os outros dois conjuntos de dados. Todos, exceto o GFS, mostram claramente ventos mais fracos no olho dos ciclones. Wind intensity of two tropical cyclones obtained by different data sets A B S T R A C TWhen the tropical cyclones reach winds with intensity equal or higher than 119 km/h, they develop a structure known as the eye at its center. The strongest winds in the system are found immediately after the eye. In a recent study for Haiyan and Haima cyclones, the question of the quality of the Global Forecast System (GFS) data in representing the winds once the maximum winds appeared in the system eye was raised. Therefore, this study aims to evaluate how different data sets (GFS, ERA5, ERA-Interim and CCMP) represent the winds in these two tropical cyclones. ERA5 and GFS show cyclones with more intense winds than the other datasets. Except the GFS, the other data clearly show weaker winds in the cyclone eye.Keywords: analyzes; cyclones; meteorology; reanalysis

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GRACE-FO radio occultation data processing – First result

10.5194/gstm2020-76 ◽

2020 ◽

Author(s):

Torsten Schmidt ◽

Patrick Schreiner ◽

Byron Iijima ◽

Chi Ao

Keyword(s):

Data Processing ◽

Radio Occultation ◽

Temperature Data ◽

Gps Satellites ◽

Weather And Climate ◽

First Results ◽

Software Updates ◽

Occultation Data ◽

Radio Occultation Data

An objective of the GRACE-FO mission is the continuation of GRACE radio occultation measurements successfully performed between 2006 and 2017. GRACE and GRACE-FO radio occultations contribute to the overall radio occultation dataset used in weather and climate applications. Since mid-2019 rising occultations from GF1 are available while setting radio occultations from GF2 are still disabled. After several on-board software updates and raw data reader improvements about 280 daily GF1 radio occultations are available since March 2020. Currently GF1 radio occultation data are processed on the basis of different measured variables: For different GPS satellites a combination of L1CA/L2P, L1CA/L2C, or L1CA/L5 is available. In this study first results of GF1 processing are presented. Refractivity and temperature data up to an altitude of 60 km will be compared with ECMWF operational analyses and the quality of the different measured variables will be evaluated.

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The Henetus wave forecast system in the Adriatic Sea

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-2965-2011 ◽

2011 ◽

Vol 11 (11) ◽

pp. 2965-2979 ◽

Cited By ~ 12

Author(s):

L. Bertotti ◽

P. Canestrelli ◽

L. Cavaleri ◽

F. Pastore ◽

L. Zampato

Keyword(s):

Adriatic Sea ◽

Model Performance ◽

Venice Lagoon ◽

Wind Fields ◽

Forecast System ◽

Meteorological Model ◽

Wave Forecast ◽

Constant Quality ◽

Operational Range

Abstract. We describe the Henetus wave forecast system in the Adriatic Sea. Operational since 1996, the system is continuously upgraded, especially through the correction of the input ECMWF wind fields. As these fields are of progressively improved quality with the increasing resolution of the meteorological model, the correction needs to be correspondingly updated. This ensures a practically constant quality of the Henetus results in the Adriatic Sea since 1996. After suitable and extended validation of the quality of the results at different forecast ranges, the operational range has been recently extended to five days. The Henetus results are used also to improve the tidal forecast on the Venetian coasts and the Venice lagoon, particularly during the most severe events. Extensive statistics on the model performance are provided, both as analysis and forecast, by comparing the model results versus both satellite and buoy data.

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Quality-of-Service Analysis of Priority Queueing Systems under Long-Range Dependent and Short-Range Dependent Traffic

Recent Advances in Modeling and Simulation Tools for Communication Networks and Services ◽

10.1007/978-0-387-73908-3_19 ◽

2007 ◽

pp. 367-388

Author(s):

Xiaolong Jin ◽

Geyong Min

Keyword(s):

Quality Of Service ◽

Long Range ◽

Short Range ◽

Queueing Systems ◽

Priority Queueing

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Seasonal Forecasting of Tropical Cyclone Landfall Using ECMWF’s System 4

Weather and Forecasting ◽

10.1175/waf-d-18-0032.1 ◽

2019 ◽

Vol 34 (5) ◽

pp. 1239-1255 ◽

Cited By ~ 1

Author(s):

Dan L. Bergman ◽

Linus Magnusson ◽

Johan Nilsson ◽

Frederic Vitart

Keyword(s):

Tropical Cyclone ◽

North American ◽

Seasonal Forecast ◽

Seasonal Forecasting ◽

Forecast System ◽

Forecast Period ◽

The North ◽

Hurricane Season ◽

Tropical Cyclone Landfall

Abstract A method has been developed to forecast seasonal landfall risk using ensembles of cyclone tracks generated by ECMWF’s seasonal forecast system 4. The method has been applied to analyze and retrospectively forecast the landfall risk along the North American coast. The main result is that the method can be used to forecast landfall for some parts of the coast, but the skill is lower than for basinwide forecasts of activity. The rank correlations between forecasts issued on 1 May and observations are 0.6 for basinwide tropical cyclone number and 0.5 for landfall anywhere along the coast. When the forecast period is limited to the peak of the hurricane season, the landfall correlation increases to 0.6. Moreover, when the forecast issue date is pushed forward to 1 August, basinwide tropical cyclone and hurricane correlations increase to 0.7 and 0.8, respectively, whereas landfall correlations improve less. The quality of the forecasts is in line with that obtained by others.

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A Nonparametric Ensemble Postprocessing Approach for Short-Range Visibility Predictions in Data-Sparse Areas

Weather and Forecasting ◽

10.1175/waf-d-17-0066.1 ◽

2018 ◽

Vol 33 (3) ◽

pp. 835-855 ◽

Cited By ~ 1

Author(s):

William R. Ryerson ◽

Joshua P. Hacker

Keyword(s):

Air Force ◽

Short Range ◽

Predictive Power ◽

Cross Validation ◽

Physical Mechanism ◽

Cloud Water ◽

Weather Research And Forecasting ◽

Forecast System ◽

Clear Cases ◽

Observational Record

Abstract This work develops and tests the viability of obtaining skillful short-range (<20 h) visibility predictions using statistical postprocessing of a 4-km, 10-member Weather Research and Forecasting (WRF) ensemble configured to closely match the U.S. Air Force Mesoscale Ensemble Forecast System. The raw WRF predictions produce excessive forecasts of zero cloud water, which is simultaneously predicted by all ensemble members in 62% of observed fog cases, leading to zero ensemble dispersion and no skill in these cases. Adding dispersion to the clear cases by making upward adjustments to cloud water predictions from individual members not predicting fog on their own provides the best chance to increase the resolution and reliability of the ensemble. The technique leverages traits of a joint parameter space in the predictions and is generally most effective when the space is defined with a moisture parameter and a low-level stability parameter. Cross-validation shows that the method adds significant overnight skill to predictions in valley and coastal regions compared to the raw WRF forecasts, with modest skill increases after sunrise. Postprocessing does not improve the highly skillful raw WRF predictions at the mountain test sites. Since the framework addresses only systematic WRF deficiencies and identifies parameter pairs with a clear, non-site-specific physical mechanism of predictive power, it has geographical transferability with less need for recalibration or observational record compared to other statistical postprocessing approaches.

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Upper wind observing systems used for meteorological operations

Annales Geophysicae ◽

10.1007/s00585-994-0691-2 ◽

1994 ◽

Vol 12 (8) ◽

pp. 691-710 ◽

Cited By ~ 2

Author(s):

J. Nash

Keyword(s):

Measurement Errors ◽

Wind Component ◽

Random Errors ◽

The United Kingdom ◽

Radar Systems ◽

Wind Profiler Radar ◽

Wind Measurements ◽

Balloon Measurements ◽

Observing Systems

Abstract. Methods of upper wind measurements used in operational meteorology have been reviewed to provide guidance to those developing wind profiler radar systems. The main limitations of the various methods of tracking weather balloons are identified using results from the WMO radiosonde comparisons and additional tests in the United Kingdom. Costs associated with operational balloon measurements are reviewed. The sampling and quality of operational aircraft wind observations are illustrated with examples from the ASDAR system. Measurement errors in horizontal winds are quantified wherever possible. When tracking equipment is functioning correctly, random errors in southerly and westerly wind component measurements from aircraft and weather balloons are usually in the range 0.5-2 m s-1.

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Thermal Degradation of SiGe Interfaces Studied by X-Ray Reflectivity and Diffraction

MRS Proceedings ◽

10.1557/proc-239-455 ◽

1991 ◽

Vol 239 ◽

Cited By ~ 5

Author(s):

J. M. Hudson ◽

A. R. Powell ◽

D. K. Bowen ◽

M. Wormington ◽

B. K. Tanner ◽

...

Keyword(s):

Short Range ◽

Grazing Incidence ◽

Sige Layer ◽

Interface Roughness ◽

Total Thickness ◽

X Ray Diffraction ◽

X Ray ◽

Surface And Interface ◽

Superlattice Structures

ABSTRACTWe demonstrate the use of x-ray diffraction to provide accurate compositional information, together with grazing incidence reflectivity to provide information on layer thicknesses and surface and interface roughnesses, on Si/Si1-xGex superlattice structures of less than 200nm total thickness.The quality of SiGe interfaces has been investigated in superlattices where x varies from 0.1 to 0.5. At low Ge compositions the interfaces are shown to be smooth to a few angstroms. However, as the Ge composition in the SiGe layer approaches 50%, severe roughness is observed at the SiGe to Si interfaces, although the Si to SiGe interfaces remain relatively smooth.Upon annealing for one hour at 850°C the Ge diffuses outwards from the SiGe layers and can be closely modelled by inclusion of a (2.4±0.3)nm linearly graded layer either side of the SiGe layer into a simulation program. The long range roughness at the SiGe to Si interface is lost upon annealing leaving only a short range roughness of similar size to the Si to SiGe interface roughness.Reflectivity measurements have been shown to distinguish between interface roughness and interdiffusion for the annealed system.

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