- Event Weeks
- NoWCasting SAF - Event Week 2013
NoWCasting SAF - Event Week 2013
EUMeTrain organised an event week on products of the NWC-SAF from 18th to 21st November 2013. There were 8 sessions starting on Monday morning. The presentations comprised nowcasting products based on MSG and PPS satellites like cloud products, precipitation and wind products. Each session consist of 2 parts; first an overview on the product from the developer side and the second part with some typical applications of the data from the users side.
Session 1: Introduction to NWCSAF
The general objective of the NWC SAF is to provide operational services to ensure optimum use of Meteorological satellite data in Nowcasting and Very Short Range Forecasting. To achieve this goal, the NWC SAF is responsible for the development and maintenance of both satellite derived products and of appropriate SW Packages, as well as user support and related tasks.
This lecture intends to provide an overview of the NWC SAF project including objectives, consortium composition, phases, organization, services and products.Recording Pilar Fernández
This lecture is intended to give a detailed overview of the NWCSAF User Services provided through the Helpdesk tool. The attendants will be shown the different services available for users and also the information available for non-users.
Some statistics about the Helpdesk use made by the users (Mail Box, SPR, etc..) will also be shown.Recording Ana Sánchez Piqué
Session 2: GEO: Cloud products and applications
This 30 minutes presentation gives an overview of the cloud products that can be retrieved from the MSG/NWCSAF software. These products are the cloud mask (including dust and volcanic ash flag), the cloud type (including the cloud thermodynamical phase), and the cloud top temperature and height. The algorithms will be outlined and some validation results be presented. Finally short information will be given on the new cloud microphysics product planned in the NWC/GEO software version 2015.Recording Herve Le Gléau
In a second talk, Thomas Krennert will present case studies using the NWCSAF Cloud Products.Recording Thomas Krennert
Session 3: GEO: Precipitation Products and Applications
To provide the forecasters with tools for severe weather events monitoring with a suitable spatial and temporal resolution is very important. The NWCSAF project develops several products to make easier forecasters their nowcasting tasks.
The NWCSAF/MSG software package contains two products devoted to precipitation. Precipitating Clouds (PC) product assigns a probability of precipitation occurrence on each SEVIRI pixel. Convective Rainfall Rate (CRR) product estimates rain rates on convective, and stratiform associated to convection, events. The algorithms, on which those products are based, have currently two different approaches.
PC product takes advantage of surface temperatures and of those SEVIRI spectral features which have the highest correlation with precipitation, to construct a Precipitation Index (PI). According to this PI, which has been calibrated against rain gauges, a likelihood of precipitation occurrence is assigned to each SEVIRI pixel. CRR algorithm assigns rain rates to each pixel according to some SEVIRI channel information and some calibration functions, which have been calibrated using radar data. The influences of environmental and orographic effects on the precipitation distribution are taken into account through some corrections that use NWP data. Besides, two new products are included in the NWCSAF/MSG v2013 software package. These products also estimate the probability of precipitation and convective rainfall rates using a common approach, which takes advantage of cloud microphysical properties.Recording Cecilia Marcos
In a second talk, Natasa Strelec-Mahovic will present applications of the NWCSAF Precipitation Products.Recording Natasa Strelec-Mahovic
Session 4: GEO: Clear Air Products and Applications
Since 2010, the PGE13 SEVIRI Physical Retrieval (SPhR) is available as an operational product of the NWCSAF/MSG software package. The algorithm is based on the physical retrieval algorithm for GOES developed by Dr. Jun Li (CIMSS at Wisconsin University) but using RTTOV as the radiative transfer model and the coefficients adapted for SEVIRI. The PGE13 has been optimized for the purpose of operational implementation; near real time images could be seen on the NWC SAF reference system (http://www.nwcsaf.org).
The improvements on version 2013 of PGE13 are presented first. The main improvement on the 2013 version is that it allows the use as the background NWP input of ECMWF GRIB files on hybrid levels; the 2012 version only allows the use as NWP input of GRIB files on fixed pressure levels.
This step is a small milestone in the exploitation of this kind of MSG L2 products. Now, the spatial and temporal resolution could be used together with vertical resolution provided by the hybrid levels GRIB files to get information of 3D structures. The reason it that the use of hybrid GRIB files as input to the algorithm avoids the stepwise aspect on the vertical cross sections created by the linear interpolation between too separated levels in the fixed pressure levels PGE13 version. Other point is that the local execution of PGE13 allows the generation of optional files with fields like 3D equivalent potential temperature arrays. Thus, forecasters can fully exploit the 3D structure allowing the detection of instability vertical gradients on medium levels.
All these changes allow forecasters the use of the PGE13 for a better monitoring of key ingredients in regions where likely triggering of convective storm could develop and also advise of the regions where the NWP disagree with the PGE13 physical retrieved profiles. The use of PGE13 in several case studies will be presented.Recording Miguel A. Martinez
The NWCSAF Clear Air product consists of total and layer water vapour contents and instability indices. This product is retrieved from SEVIRI data for cloud-free pixels. As it can be calculated in 15-minute time step, even in 5-minute time step it is usable to monitor convection ability.
Case studies will be presentation and analyzed: cases, when the NWP forecasted and the satellite retrieved convective environmental parameters are close to each other and when not. We will show selected cases when the NWCSAF Clear Air product has added value compared to the NWP forecast. The effect of the undetected clouds is also analysed.
As optional output the whole retrieved temperature and humidity profiles can be study. We show a case when the retrieved profiles were also analyzed. Statistical results will be presented on using the satellite retrieved Clear Air environmental parameters to separate stable from unstable environments and the environment where forming severe storm is not likely from the environment where it is possible.Recording Maria Putsay
Session 5: GEO - High Resolution Winds and Applications
The “NWC SAF/HRW High Resolution Winds” provides a detailed calculation of Atmospheric Motion Vectors locally and in near real time. It calculates the AMVs considering cloud and humidity patterns in up to seven different MSG/SEVIRI channels (HRVIS, VIS06, VIS08, WV062, WV073, IR108, IR120), together with NWP data and the “NWC SAF Cloud products (Cloud type, Cloud top temperature and height)”.
It considers up to two tracer scales (Basic and detailed), two tracer determination methods (Gradient and tracer characteristics), two tracking methods (Euclidean distance or cross correlation), and two Height level assignment methods (Brightness temperature interpolation method and Cross correlation contribution method). As other AMV products worldwide it also includes a quality control flagging based on the Quality Indicator Method developed at EUMETSAT.
NWC SAF/HRW product can be useful in Nowcasting applications in synergy with other data available to the forecaster: monitoring of low level convergence, divergence at the top of developed systems, or other cases of small scale circulation or wind singularities. It can also be used as an input in analysis and forecasting applications like NWP models. The development and main characteristics of the product are explained with examples, useful for the potential users to know what the product can offer. The validation results related to the latest version on the product (HRW v4.0) are also explained.Recording Javier Garcia-Pereda
The role of the Atmospheric Motion Vectors (AMV) in the modern data assimilation systems is evident nowadays. The AMVs – along with satellite observations – have an important key for our operational ALADIN data assimilation system as well. In the framework of the EUMETSAT SAF High Resolution Winds (HRW) products had been developed by AEMET for Nowcasting and Very Short Range Forecasting purposes. The HRW products provide quasi real time data of AMVs from MSG HRVIS and IR10.8 channels every hour in a day. A collaboration between AEMET and OMSZ have been focused to compare the benefit of the operationally used AMVs (received through the EumetCAST) with the newly processed HRW winds. Recent work was an extensive evaluation and monitoring of the assimilation and forecast system. The impact of the AMV winds was examined using different diagnostic techniques, verifications tools and case studies. The first results are promising regarding the use of the HRW AMV. The statistical scores on the full domain showed neutral or slightly positive impact in most of the parameters and the experiment based on HRW AMV data provided better estimate of extreme precipitation events.Recording Mate Mile
Session 6: GEO: Convection - Rapid Development Thunderstorms (RDT) and Applications
RDT-CW (Rapid Development Thunderstorm Convection Warning) product is an object-oriented diagnostic for convective clouds or cells. RDT-CW is mainly based on satellite data. RDT-CW software tracks clouds, identifies those that are convective (discrimination), and provides some descriptive attributes for their dynamics. Year after year many attributes have been added to the convection object. These improvements offer end-users the possibility to focus on specific parameters according to their center of interest: dynamic of the system (cooling rate, motion vector) lightning activity, rainfall, main cloud phase of the cell, etc. These attributes may come from various sources such as NWP data, other PGEs (Product Generation Element), lightning network. In the v2013 release, an overshooting top detection inside RDT cell is proposed to users. This new attribute allows to focus on potentially hazardous areas.
RDT cell is proposed to users. This new attribute allows to focus on potentially hazardous areas. In the future releases the description of convective cells will be enriched, giving a high priority to the use of other SAFNWC products. A nowcast of RDT up to one hour will be implemented.Recording Jean-Marc Moisselin
Several SAFNWC processing chains are implemented at Meteo-France over various geographical areas: those covered by MSG of course, but also those covered by other geostationary satellites, like overseas territory where Meteo-France centers are still implemented. Forecasters in these centers are the main users to benefit from RDT as an additional product. Productions over Europe and Africa benefit to Aeronautical forecasters from Meteo-France’s National Forecast center, to French Army, and also to ACMAD, Niamey.
A target visualization tool with nowcasting capabilities will be presented, which allows taking advantage from RDT end-product. Presentation of RDT for various situations and over various areas will also be undertaken, and the latest development implemented in v2013 release will be highlighted.Recording Frédéric Autones
Session 7: GEO: Met. Systems - Automatic Satellite Image Interpretation (ASII)
PGE10 of the SAFNWC/MSG provides an automatic satellite image interpretation in terms of conceptual models (CMs). Conceptual models are important tools for forecasters in diagnosis, nowcasting and very short range forecasting; they describe a synthesis of typical features in satellite images as well as in other synoptic material (for instance numerical model output parameters) and the physical processes causing them. A CM diagnosis cannot only be used for detection of an ongoing process but also for the determination of the stage of development within this process. This presentation will focus on the practical applications of ASII by showing examples of analysed synoptic weather situations.Recording Andreas Wirth
In a second talk, Eunha Son from the Korean Meteorological Service will talk about applications of NWC SAF modules such as RDT, CRR, HRW and ASII in KMA, ongoing works and future works related to NWC SAF.Recording Eunha Sohn
Session 8: PPS: Cloud Products
The PPS package for Polar orbiting satellites produces Cloud Products for NOAA, METOP and the NPP-Suomi satellites. Products available are Cloud mask (CM), Cloud Type (CT), Cloud Top Temperature and Height (CTTH) and Cloud Physical Properties (CPP) during day CPP validated outputs are cloud phase and cloud liquid water path, as well as the auxiliary output fields cloud optical thickness, effective droplet radius and ice water path.
While the software package was originally aimed at producing NWC products for local satellite receiving stations, a subset of cloud products (CT and CTTH) are now also available in near real time via EUMETCAST within the NWC-EARS service.
We will present examples of PPS cloud products concentrating on CT, CTTH and CPP products, as well as giving a short preview of updates for PPS with version 2014.Recording Anna Eronn
In a second talk, Thomas Heinemann will present the EARS-NWC service. Data from the SAFNWC PPS package are computed at EUMETSAT headquarter and distributed via Eumetcast service to end-users.Recording Thomas Heinemann