scholarly journals PREDICTION OF CUMULONIMBUS (CB) CLOUD BASED ON INTEGRATED FORECAST SYSTEM (IFS) OF EUROPEAN MEDIUM-RANGE WEATHER FORECAST (ECMWF) IN THE FLIGHT INFORMATION REGION (FIR) OF JAKARTA AND UJUNG PANDANG

2020 ◽  
Vol 21 (2) ◽  
Author(s):  
Achmad Fahruddin Rais ◽  
Fani Setiawan ◽  
Rezky Yunita ◽  
Erika Meinovelia ◽  
Soenardi Soenardi ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Cloud Cover ◽  
Convective Cloud ◽  
Weather Forecast ◽  
Forecast System ◽  
Medium Range Weather Forecast ◽  
Medium Range ◽  
Ujung Pandang ◽  
Categorical Verification ◽  
Ecmwf Model

This study was focused on cumulonimbus (Cb) cloud prediction based on Integrated Forecast System (IFS) European Medium-Range Weather Forecast (ECMWF) model in the Flight Information Region (FIRs) Jakarta and Ujung Pandang. The Cb cloud prediction was calculated using convective cloud cover (CC) of the precipitation product. The model predictability was examined through categorical verification. The Cb cloud observation was based on brightness temperature (BT) IR1 and brightness temperature difference (BTD) IR1-IR2. The results showed that CC 50%' predictor was the best predictor to estimate the Cb cloud. The study in the period other than 2019 is suggested for the next research because Indian Ocean Dipole (IOD) is extreme that may affect the Cb cloud growth in the study area.

Impact of the Different Components of 4DVAR on the Global Forecast System of the Meteorological Service of Canada

2007 ◽  
Vol 135 (6) ◽  
pp. 2355-2364 ◽  
Author(s):  
Stéphane Laroche ◽  
Pierre Gauthier ◽  
Monique Tanguay ◽  
Simon Pellerin ◽  
Josée Morneau
Keyword(s):  
Data Assimilation ◽  
Positive Impact ◽  
Weather Forecast ◽  
Forecast Model ◽  
Variational Data Assimilation ◽  
Global Forecast System ◽  
Forecast System ◽  
Medium Range Weather Forecast ◽  
Medium Range ◽  
The Impact

Abstract A four-dimensional variational data assimilation (4DVAR) scheme has recently been implemented in the medium-range weather forecast system of the Meteorological Service of Canada (MSC). The new scheme is now composed of several additional and improved features as compared with the three-dimensional variational data assimilation (3DVAR): the first guess at the appropriate time from the full-resolution model trajectory is used to calculate the misfit to the observations; the tangent linear of the forecast model and its adjoint are employed to propagate the analysis increment and the gradient of the cost function over the 6-h assimilation window; a comprehensive set of simplified physical parameterizations is used during the final minimization process; and the number of frequently reported data, in particular satellite data, has substantially increased. The impact of these 4DVAR components on the forecast skill is reported in this article. This is achieved by comparing data assimilation configurations that range in complexity from the former 3DVAR with the implemented 4DVAR over a 1-month period. It is shown that the implementation of the tangent-linear model and its adjoint as well as the increased number of observations are the two features of the new 4DVAR that contribute the most to the forecast improvement. All the other components provide marginal though positive impact. 4DVAR does not improve the medium-range forecast of tropical storms in general and tends to amplify the existing, too early extratropical transition often observed in the MSC global forecast system with 3DVAR. It is shown that this recurrent problem is, however, more sensitive to the forecast model than the data assimilation scheme employed in this system. Finally, the impact of using a shorter cutoff time for the reception of observations, as the one used in the operational context for the 0000 and 1200 UTC forecasts, is more detrimental with 4DVAR. This result indicates that 4DVAR is more sensitive to observations at the end of the assimilation window than 3DVAR.

scholarly journals Detection and thermal description of medicanes from numerical simulation

2014 ◽  
Vol 14 (5) ◽  
pp. 1059-1070 ◽  
Author(s):  
M. A. Picornell ◽  
J. Campins ◽  
A. Jansà
Keyword(s):  
Numerical Simulation ◽  
Thermal Structure ◽  
Weather Prediction ◽  
Weather Forecast ◽  
Small Scale ◽  
Medium Range Weather Forecast ◽  
Warm Core ◽  
Strong Winds ◽  
Nwp Model ◽  
Ecmwf Model

Abstract. Tropical-like cyclones rarely affect the Mediterranean region but they can produce strong winds and heavy precipitations. These warm-core cyclones, called MEDICANES (MEDIterranean hurriCANES), are small in size, develop over the sea and are infrequent. For these reasons, the detection and forecast of medicanes are a difficult task and many efforts have been devoted to identify them. The goals of this work are to contribute to a proper description of these structures and to develop some criteria to identify medicanes from numerical weather prediction (NWP) model outputs. To do that, existing methodologies for detecting, characterizating and tracking cyclones have been adapted to small-scale intense cyclonic perturbations. First, a mesocyclone detection and tracking algorithm has been modified to select intense cyclones. Next, the parameters that define the Hart's cyclone phase diagram are tuned and calculated to examine their thermal structure. Four well-known medicane events have been described from numerical simulation outputs of the European Centre for Medium-Range Weather Forecast (ECMWF) model. The predicted cyclones and their evolution have been validated against available observational data and numerical analyses from the literature.

scholarly journals Analisis Kondisi Atmosfer Terkait Siklon Tropis Pabuk Serta Pengaruhnya Terhadap Tinggi Gelombang di Perairan Kepulauan Riau

2020 ◽  
Vol 8 (2) ◽  
pp. 111
Author(s):  
Diana Cahaya Siregar ◽  
Vivi Putrima Ardah ◽  
Arlin Martha Navitri
Keyword(s):  
Tropical Cyclone ◽  
Satellite Imagery ◽  
Vertical Velocity ◽  
Atmospheric Condition ◽  
Weather Forecast ◽  
Distribution Data ◽  
Medium Range Weather Forecast ◽  
Wavewatch Iii ◽  
Medium Range ◽  
The Impact

Abstract Tropical cyclones is a synoptic scale low pressure system which can have an impact, both directly or indirectly to its traversed area. On January 1 to 6, 2019, Pabuk tropical cyclone was active on the South China Sea which its movement was to the west with its maximum wind speed was 64 knots. The aim of this study was to know the impact of Pabuk tropical cyclone to the atmospheric condition and sea wave on the Riau Islands region. This study used convective index analysis using IR1 channel of Himawari-8 satellite imagery and rainfall distribution data from rainfall observation by meteorological stations which are in the Riau Islands region. European Center for Medium-Range Weather Forecast (ECMWF) reanalysis data likes relative humidity, vertical velocity, and divergence was used to describe the atmospheric condition during the life time of Pabuk tropical cyclone. Wavewatch-III data was used to describe the condition of sea waves on the Riau Islands region. The results showed that Pabuk tropical cyclone had an impact on the growth of convective clouds which it caused the light to moderate rainfall quite evenly in the Riau Islands region. Besides, it was impact to the potential of high waves reached 4.5 meters on the northern of Anambas Sea and 7.0 meters on the north-eastern of Natuna Sea.Key words: Tropical cyclone, satellite imagery, wave height Abstrak Siklon tropis merupakan sistem tekanan rendah berskala sinoptik yang berdampak secara langsung maupun tidak langsung terhadap wilayah yang dilalui. Pada tanggal 1-6 Januari 2019, siklon tropis Pabuk muncul di wilayah Laut Cina Selatan dengan pergerakan ke arah barat dan kecepatan angin maksimumnya mencapai 64 knots. Penelitian ini dilakukan untuk mengkaji dampak yang ditimbulkan oleh siklon tropis Pabuk terhadap kondisi atmosfer dan gelombang laut di wilayah Kepulauan Riau. Penelitian ini menggunakan analisis indeks konvektif dari data citra satelit Himawari-8 kanal IR1 dan analisis sebaran hujan menggunakan data pengamatan curah hujan dari beberapa stasiun meteorologi yang ada di Kepulauan Riau. Data reanalisis European Centre for Medium-Range Weather Forecast (ECMWF) berupa kelembaban udara, vertical velocity, dan divergensi diolah untuk menggambarkan kondisi atmosfer pada masa hidup siklon tropis Pabuk. Data gelombang Wavewatch-III digunakan untuk menggambarkan kondisi gelombang laut di sekitar wilayah Kepulauan Riau. Hasil penelitian menunjukkan bahwa aktifnya siklon tropis Pabuk berdampak terhadap pertumbuhan awan konvektif yang menimbulkan hujan ringan hingga sedang yang cukup merata di wilayah Kepulauan Riau. Selain itu, berdampak juga pada potensi terjadinya gelombang tinggi mencapai 4,5 meter di sebelah utara Perairan Anambas dan 7,0 meter di sebelah timur laut Perairan Natuna.Kata Kunci: Siklon tropis, citra satelit, tinggi gelombang

scholarly journals Statistical interpretation of general circulation model: A prospect for automation of medium range local weather forecast in India

MAUSAM ◽  
2021 ◽  
Vol 47 (3) ◽  
pp. 229-236
Author(s):  
ASHOK KUMAR ◽  
PARVINDER MAINI
Keyword(s):  
General Circulation ◽  
Weather Forecasting ◽  
Monsoon Season ◽  
Circulation Model ◽  
Weather Forecast ◽  
General Circulation Models ◽  
Statistical Interpretation ◽  
Medium Range Weather Forecast ◽  
Medium Range ◽  
Local Weather

The General Circulation Models (GCM), though able to provide reasonably good medium range weather forecast. have comparatively less skill in forecasting location-specific weather. This is mainly due to the poor representation of 16cal topography and other features in these models. Statistical interpretation (SI) of GCM is very essential in order to improve the location-specific medium range local weather forecast. An attempt has been made at the National Centre for Medium Range Weather Forecasting (NCMRWF), New Delhi to do this type of objective forecasting. Hence location-specific SI models are developed and a bias free forecast is obtained. One of the techniques for accomplishing this, is the Perfect Prog. Method (PPM). PPM models for precipitation (quantitative, probability, yes/no) and maximum minimum temperature are developed for monsoon season (June to August) for 10 stations in lndia. These PPM models and the output from the GCM (R-40) operational at NCMRWF, are then used to obtain the SI forecast. An indirect method based upon SI forecast and observed values of previous one or two seasons, for getting bias free forecast is explained. A comparative study of skill of bias free SI and final forecast, with the observed, issued from NCMRWF to 10 Agromet Field Units (AMFU) during monsoon season 1993, has indicated that automation of medium range local weather forecast can be achieved with the help of SI forecast.

scholarly journals Fire weather index: the skill provided by ECMWF ensemble prediction system

2020 ◽  
Author(s):  
Francesca Di Giuseppe ◽  
Claudia Vitolo ◽  
Blazej Krzeminski ◽  
Jesús San-Miguel
Keyword(s):  
Weather Forecast ◽  
Research Centre ◽  
Ensemble Prediction ◽  
Fire Weather ◽  
Prediction System ◽  
Weather Index ◽  
Fire Weather Index ◽  
Ensemble Prediction System ◽  
Medium Range Weather Forecast ◽  
Medium Range

Abstract. In the framework of the EU Copernicus program, the European Centre for Medium-range Weather Forecast (ECMWF) on behalf of the Joint Research Centre (JRC) is forecasting daily fire weather indices using its medium range ensemble prediction system. The use of weather forecast in place of local observations can extend early warnings up to 1–2 weeks allowing for greater proactive coordination of resource-sharing and mobilization within and across countries. Using one year of pre-operational service in 2017 and the fire weather index (FWI) here we assess the capability of the system globally and analyze in detail three major events in Chile, Portugal and California. The analysis shows that the skill provided by the ensemble forecast system extends to more than 10 days when compared to the use of mean climate making a case of extending the forecast range to the sub-seasonal to seasonal time scale. However accurate FWI prediction does not translate into accuracy in the forecast of fire activity globally. Indeed when all 2017 detected fires are considered, including agricultural and human induced burning, high FWI values only occurs in 50 % of the cases and only in Boreal regions. Nevertheless for very important events mostly driven by weather condition, FWI forecast provides advance warning that could be instrumental in setting up management strategies.

scholarly journals Latent Heat Flux in the Agulhas Current

2019 ◽  
Vol 11 (13) ◽  
pp. 1576 ◽  
Author(s):  
Arielle Stela Imbol Nkwinkwa N. ◽  
Mathieu Rouault ◽  
Johnny A. Johannessen
Keyword(s):  
Heat Flux ◽  
Wind Speed ◽  
Annual Cycle ◽  
Current System ◽  
Surface Wind ◽  
Weather Forecast ◽  
Specific Humidity ◽  
Medium Range Weather Forecast ◽  
Agulhas Current ◽  
Medium Range

In-situ observation, climate reanalyses, and satellite remote sensing are used to study the annual cycle of turbulent latent heat flux (LHF) in the Agulhas Current system. We assess if the datasets do represent the intense exchange of moisture that occurs above the Agulhas Current and the Retroflection region, especially the new reanalyses as the former, the National Centers for Environmental Prediction Reanalysis 2 (NCEP2) and the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis second-generation reanalysis (ERA-40) have lower sea and less distinct surface temperature (SST) in the Agulhas Current system due to their low spatial resolution thus do not adequately represent the Agulhas Current LHF. We use monthly fields of LHF, SST, surface wind speed, saturated specific humidity at the sea surface (Qss), and specific humidity at 10 m (Qa). The Climate Forecast System Reanalysis (CFSR), the European Centre for Medium-Range Weather Forecast fifth generation (ERA-5), and the Modern-Era Retrospective analysis for Research and Applications version-2 (MERRA-2) are similar to the air–sea turbulent fluxes (SEAFLUX) and do represent the signature of the Agulhas Current. ERA-Interim underestimates the LHF due to lower surface wind speeds than other datasets. The observation-based National Oceanography Center Southampton (NOCS) dataset is different from all other datasets. The highest LHF of 250 W/m2 is found in the Retroflection in winter. The lowest LHF (~100 W/m2) is off Port Elizabeth in summer. East of the Agulhas Current, Qss-Qa is the main driver of the amplitude of the annual cycle of LHF, while it is the wind speed in the Retroflection and both Qss-Qa and wind speed in between. The difference in LHF between product are due to differences in Qss-Qa wind speed and resolution of datasets.

scholarly journals Analysis of extreme summers and prior late winter/spring conditions in central Europe

2013 ◽  
Vol 13 (5) ◽  
pp. 1243-1257 ◽  
Author(s):  
C. Träger-Chatterjee ◽  
R. W. Müller ◽  
J. Bendix
Keyword(s):  
Soil Moisture ◽  
Atmospheric Circulation ◽  
Central Europe ◽  
Weather Forecast ◽  
Solar Irradiation ◽  
Late Winter ◽  
Seasonal Forecasts ◽  
Medium Range Weather Forecast ◽  
Medium Range ◽  
Low Precipitation

Abstract. Drought and heat waves during summer in mid-latitudes are a serious threat to human health and agriculture and have negative impacts on the infrastructure, such as problems in energy supply. The appearance of such extreme events is expected to increase with the progress of global warming. A better understanding of the development of extremely hot and dry summers and the identification of possible precursors could help improve existing seasonal forecasts in this regard, and could possibly lead to the development of early warning methods. The development of extremely hot and dry summer seasons in central Europe is attributed to a combined effect of the dominance of anticyclonic weather regimes and soil moisture–atmosphere interactions. The atmospheric circulation largely determines the amount of solar irradiation and the amount of precipitation in an area. These two variables are themselves major factors controlling the soil moisture. Thus, solar irradiation and precipitation are used as proxies to analyse extreme sunny and dry late winter/spring and summer seasons for the period 1958–2011 in Germany and adjacent areas. For this purpose, solar irradiation data from the European Center for Medium Range Weather Forecast 40-yr and interim re-analysis dataset, as well as remote sensing data are used. Precipitation data are taken from the Global Precipitation Climatology Project. To analyse the atmospheric circulation geopotential data at 850 hPa are also taken from the European Center for Medium Range Weather Forecast 40-yr and interim re-analysis datasets. For the years in which extreme summers in terms of high solar irradiation and low precipitation are identified, the previous late winter/spring conditions of solar irradiation and precipitation in Germany and adjacent areas are analysed. Results show that if the El Niño–Southern Oscillation (ENSO) is not very intensely developed, extremely high solar irradiation amounts, together with extremely low precipitation amounts during late winter/spring, might serve as precursor of extremely sunny and dry summer months to be expected.

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