DOCSLIB.ORG

REFORECASTS an Important Dataset for Improving Weather Predictions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
REFORECASTS an Important Dataset for Improving Weather Predictions REFORECASTS An Important Dataset for Improving Weather Predictions BY THOMAS M. HAMILL, JEFFREY S. WHITAKER, AND STEVEN L. MULLEN Statistical correction of today’s numerical forecast using a long set of reforecasts (hindcasts) dramatically improves its forecast skill. eanalyses such as the National Centers for reanalysis datasets have facilitated a wide range of Environmental Prediction (NCEP)–National research; for example, the Kalnay et al. (1996) article R Center for Atmospheric Research (NCAR) re- above has been cited more than 3200 times. analysis (Kalnay et al. 1996) and the European Centre In this article, we explore the value of a companion for Medium-Range Weather Forecasts (ECMWF) dataset to reanalyses, which we shall call “reforecasts.” 40-year reanalysis (ERA-40; Uppala et al. 2005) have These are retrospective weather forecasts generated become heavily used products for geophysical science with a fixed numerical model. Model developers research. These reanalyses run a practical, consistent could use them for diagnosing model bias, thereby data assimilation and short-range forecast system facilitating the development of new, improved ver- over a long period of time. While the observation sions of the model. Others could use them as data type and quality may change somewhat, the forecast for statistically correcting weather forecasts, thereby model and assimilation system are typically fixed. developing improved, user-specific products [e.g., This facilitates the generation of a reanalysis dataset model output statistics (MOS) Glahn and Lowry that is fairly consistent in quality over time. These 1972; Carter et al. 1989]. Others may use them for studies of atmospheric predictability. Unfortunately, extensive sets of reforecasts are not commonly pro- AFFILIATIONS: HAMILL AND WHITAKER—NOAA Earth System duced utilizing the same model version as is run Research Lab, Physical Sciences Division, Boulder, Colorado; operationally. These computationally expensive MULLEN—Institute of Atmospheric Physics, University of Arizona, reforecasts are “squeezed out” by operational data Tucson, Arizona assimilation and forecast models that are run at as CORRESPONDING AUTHOR: Dr. Thomas M. Hamill, NOAA fine a resolution as possible. Earth Systems Research Lab, Physical Sciences Division, Boulder, CO 80305-3328 Would the additional forecast improvement and E-mail: [email protected] diagnostic capability provided by reforecasts make them worth the extra computational resources they The abstract for this article can be found in this issue, following the table of contents. require? To explore this, we recently generated a DOI:10.1175/BAMS-87-1-33 prototype 25-yr, 15-member ensemble reforecast dataset using a 1998 version of the NCEP Medium In final form 12 August 2005 ©2005 American Meteorological Society Range Forecast (MRF) model run at T62 resolution, which is admittedly a resolution far from being state AMERICAN METEOROLOGICAL SOCIETY JANUARY 2006 | 33 of the art in operational numerical weather prediction through the use of the reforecasts. Because reforecast- centers in 2005. Despite the coarse resolution of this ing using higher-resolution models can be expensive, dataset, we were able to make probabilistic week-2 implementing this idea could require the purchase or forecasts that were more skillful than the operational reallocation of computer resources. Thus, the imple- NCEP forecasts that are based on higher-resolution mentation of reforecasting requires discussion at the models (Hamill et al. 2004). Others have also dem- top levels of the weather services. onstrated the utility of reforecasts for improving pre- We will provide a description of this dataset in dictions. Rajagopalan et al. (2002) and Stefanova and “Description of the reforecast dataset” and illustrate how Krishnamurti (2002) used multimodel reforecasts users can download raw data. We then demonstrate a to improve seasonal predictions, and Vitart (2004) range of potential applications in “Some applications at demonstrated improved monthly forecasts using a the reforecast data,” illustrating how such datasets may smaller reforecast dataset. Other smaller reforecast be used to inform a variety of forecast problems. “How datasets also have been produced as companions can reforecasts be integrated into operational numerical to reanalysis datasets, but have not been used for weather prediction?” discusses the manner in which real-time statistical corrections of forecasts (Kistler reforecasts may be able to be integrated into operational et al. 2001; Mesinger et al. 2005). The novelty of the NWP facilities without excessive disruption. reforecast dataset discussed here is its length (every day, from 1979 to the present), the ongoing produc- DESCRIPTION OF THE REFORECAST tion of real-time numerical forecasts from the same DATASET. A T62 resolution (roughly 200-km grid model, and that it is an ensemble of forecasts rather spacing) version of NCEP’s Global Forecasting System than a single integration. (GFS) model (Kanamitsu 1989; Kanamitsu et al. 1991; A variety of other approaches are being explored Hong and Pan 1996; Wu et al. 1997; Caplan et al. 1997, for improving probabilistic forecasts. The Develop- and references therein) was used with physics that ment of the European Multimodel Ensemble System were operational in the 1998 version of the model. for Seasonal to Interannual Prediction (DEMETER) This model was run with 28 vertical sigma levels. The project in Europe has generated probabilistic sea- reforecasts were generated at the National Oceanic sonal climate forecasts in a multimodel environment and Atmospheric Administration (NOAA) laboratory (Palmer et al. 2004; Hagedorn et al. 2005; Doblas- in Boulder, Colorado, and real-time forecasts are now Reyes et al. 2005). Statistical approaches to correct- generated at NCEP and archived in Boulder. ing weather forecasts have been tried using shorter A 15-member ensemble was produced every day training datasets, including some with multimodel from 1979 to the present, starting from 0000 UTC or multianalysis approaches (Vislocky and Fritsch initial conditions. The ensemble initial conditions con- 1995, 1997; Hamill and Colucci 1997, 1998; Eckel and sisted of a control initialized with the NCEP–NCAR Walters 1998; Krishnamurti et al. 1999; Roulston and reanalysis (Kalnay et al. 1996) and a set of seven bred Smith 2003; Raftery et al. 2005; Wang and Bishop pairs of initial conditions (Toth and Kalnay 1993, 1997) 2005). Results presented here will reinforce our previ- that are recentered each day on the reanalysis initial ous assertion (Hamill et al. 2004) that for many dif- condition. The breeding method was the same as that ficult problems, such as long lead forecasts, forecasts used operationally in January 1998. The forecasts ex- of rare events, or forecasts of surface variables with tend to 15 days lead, with data archived every 12 h. significant bias, a large training sample size afforded Because of the large size of this dataset, we have by reforecasts may prove especially beneficial. chosen to archive only a limited set of model output. Our intent in this article is to introduce the reader Winds, temperature, and geopotential height are avail- to the several applications of reforecast data that able at the 850-, 700-, 500-, 250-, and 150-hPa levels, demonstrate the potential for improving weather and winds and temperature are available at 1000 hPa. predictions and increasing our understanding of at- The 10-m wind components, 2-m temperature, mean mospheric predictability. We also intend to stimulate sea level pressure, accumulated precipitation, convec- a serious discussion about the value of reforecasts. tive heating, precipitable water, and 700-hPa relative Is the value added so large that operational weather humidity were also archived. Data can be downloaded forecast centers should make reforecasting a regular using the online form at www.cdc.noaa.gov/refore- part of the operational numerical weather prediction cast/ (Fig. 1). Real-time data can also be obtained us- process? We will demonstrate that for the problem ing file transfer portocol (ftp) from ftp://ftp.cdc.noaa. of probabilistic precipitation forecasting there is a gov/Datasets.other.refcst/ensdata/yyyymmddhh, large, additional amount of skill that can be realized where yyyy is the year, mm is the month, dd is the 34 | JANUARY 2006 day, and hh is the hour of the initialization time. The 2000), but most utilize a simpler approach of directly real-time forecasts are typically available about 10 h finding observed analogs to the forecast. Consider a after the initialization time. situation where the forecast model is consistently too wet. In a one-step analog technique, the ensemble of SOME APPLICATIONS OF THE REFORE- observed analogs would, by construction, retain the CAST DATASET. Because reanalyses have fostered forecast’s wet bias. The two-step procedure would many creative diagnostic studies, a long reforecast da- first find similar forecasts, but if the observed data taset permits an examination and correction of weath- were drier, the second step would compensate for er forecasts in ways that were not previously possible. the wet bias. Robust statistical forecast techniques can be developed, To demonstrate the potential of this two-step the characteristics of model biases more thoroughly analog procedure, the technique was used to gen- understood, and predictability issues explored. Here, erate probabilistic forecasts of 24-h-accumulated we
Load more

Recommended publications
  • Gridded Model Output Statistics: Improving and Expanding
    6A.6 GRIDDED MODEL OUTPUT STATISTICS: IMPROVING AND EXPANDING Kathryn K. Gilbert*, Bob Glahn, Rebecca L. Cosgrove1, Kari L. Sheets, Geoffrey A. Wagner2 Meteorological Development Laboratory National Weather Service, NOAA Silver Spring, MD 1National Center for Environmental Prediction, National Weather Service, Camp Springs, MD 2Wyle Information Systems, McLean, VA 1. INTRODUCTION Since the original implementation, gridded MOS has undergone several adaptations to improve For years, National Weather Service (NWS) consistency as well as regional applicability. MDL forecasters have used Model Output Statistics developers have welcomed assessments of grid- (MOS) guidance (Glahn and Lowry 1972) as an ded MOS from local forecasters in order to make aid in producing text forecast products issued to adjustments to provide guidance which is both the user community. However, the methods fore- representative of the local area, and compatible casters use to generate products have changed with the process for generating forecasts for because of requirements to produce the official NDFD. Some of the improvements resulting from NWS 7-day forecasts on high-resolution grids. forecaster feedback include: removal of unrepre- These gridded, or digital, forecasts are put into a sentative forecasts from the analysis, expansion of National Digital Forecast Database (NDFD; Glahn the grid coverage, and modifications to the and Ruth 2003). NWS forecasters need support- land/water mask. ing guidance available on a grid, at a resolution comparable to the grid resolution used at the local In this paper, we discuss the current state of forecast office. One approach to the problem of the gridded MOS suite, as well as ongoing en- providing guidance on the required grid is to objec- hancements to the operational GFS-based MOS tively analyze forecasts at MOS stations.
    [Show full text]
  • Verification of Model Output Statistics Forecasts Associated with the North
    Allison Monarski, University of Maryland Masters Scholarly Paper, December 6, 2011 1 Department of Atmospheric and Oceanic Science Verification of Model Output Statistics forecasts associated with the North American Mesoscale model upgrade Results of work done during the Student Career Experience Program tour with the Statistical Modeling Branch (SMB) of the Meteorological Development Lab (MDL) of the National Weather Service (NWS), Silver Spring, MD, under the guidance of Mark Antolik & Kathy Gilbert, NWS/MDL/SMB I. Introduction and Motivation For the past four decades, the model output statistics (MOS) technique has been in operation and forecasters and meteorologists globally have used forecasts generated through MOS. MOS is a statistical approach to forecasting which involves determination of a relationship between a predictand and numerical weather prediction (NWP) model output for a variety of variables (predictors) at the same projection times (Glahn and Lowry 1972). Through the years, MOS has provided reliable forecasts, predicting quantities that the underlying NWP model is unable to predict. Specifically, the MOS technique can account for local effects on certain elements that the coarser resolution NWP model cannot detect (Antolik and Baker 2009). Usually, statistical forecasting systems, such as MOS, rely on many years of stable development data for optimal performance. However, due to frequent changes in the underlying structure, physics, and dynamics of the NWP models, this kind of data is difficult to obtain. Fortunately, developers at the National Weather Service’s (NWS) Meteorological Development Laboratory (MDL) have been able to show that reliable MOS forecasts can be produced using as little as just two years of data from models which are evolving (Antolik and Baker 2009).
    [Show full text]
  • Model Output Statistics Cascade to Improve Day Ahead Solar Irradiance Forecast
    Available online at www.sciencedirect.com ScienceDirect Solar Energy 117 (2015) 99–113 www.elsevier.com/locate/solener Model output statistics cascade to improve day ahead solar irradiance forecast M. Pierro a, F. Bucci a, C. Cornaro a,⇑, E. Maggioni b, A. Perotto b, M. Pravettoni c, F. Spada b a Department of Enterprise Engineering, University of Rome Tor Vergata, Via del Politecnico, 1, 00133 Rome, Italy b IDEAM srl, Via Frova 34, Cinisello Balsamo, MI, Italy c Institute of Applied Sustainability to the Build Environment, University of Applied Sciences and Arts of Southern Switzerland, Canobbio CH-6952, Switzerland Received 29 September 2014; received in revised form 9 April 2015; accepted 26 April 2015 Communicated by: Associate Editor Christian A. Gueymard Abstract In this paper a new hybrid Model Output Statistics (MOS), named MOS cascade, is developed to refine the day-ahead forecast of the global horizontal irradiance provided by the Weather Research and Forecast (WRF) model. The proposed approach is based on a sequence of two different MOS. The first, called MOSRH, is a new physically based algorithm, built to correct the treatment of humidity in the WRF radiation schemes. The second, called MOSNN, is based on artificial intelligence techniques and aims to correct the main systematic and learnable errors of the Numerical Weather Prediction output. The 1-day and 2-day forecast accuracies are analyzed via direct comparison with irradiance data measured in two sites, Rome and Lugano. The paper shows that a considerable reduction in error was achieved using MOSRH model and MOS cascade. The differences between the two sites are discussed in details.
    [Show full text]
  • Supporting Gridded Model Output Statistics Forecast Guidance System
    Supporting Gridded Model Output Statistics Forecast Guidance System Kari L. Sheets ABSTRACT The Meteorological Development Laboratory (MDL) of NOAA’s National Weather Service is creating a National Digital Guidance Database at a fine resolution to comple- ment the existing National Digital Forecast Database. To help accomplish this goal, MDL is producing a gridded Model Output Statistics (MOS) forecast guidance system. Currently, gridded MOS populates a 5-km grid with elements needed for weather fore- cast grids covering the contiguous United States. This paper describes the use of Geographic Information System (GIS) to gener- ate and quality control geophysical variables, create a station dictionary including land/water designations for the observing stations, and analyze or troubleshoot problem areas in gridded MOS weather elements. Stations used in traditional MOS development are unevenly distributed, leaving developers searching for additional data to aid in ana- lyzing these values to the aforementioned grid. GIS is integral in supplying the data to move from station-based MOS to gridded MOS. 1. Introduction The Meteorological Development Laboratory (MDL) of NOAA’s National Weather Service (NWS) is developing a National Digital Guidance Database (NDGD) at fine reso- lutions to complement the existing National Digital Forecast Database (NDFD, Glahn and Ruth 2003). To help accomplish this goal, MDL is creating a gridded forecast guid- ance system. Current forecast guidance is produced for the United States and its terri- tories at approximately 1800 hourly observing sites and over 5000 cooperative observ- ing sites by using the Model Output Statistics (MOS) technique (Glahn and Lowry 1972). In the MOS approach, observed predictand data are statistically related to predictors such as forecasts from dynamical models, surface observations, and geoclimatic infor- mation.
    [Show full text]
  • Statistical Post-Processing of Ensemble Forecasts of Temperature in Santiago De Chile
    Statistical post-processing of ensemble forecasts of temperature in Santiago de Chile Mailiu D´ıaza, Orietta Nicolisa;b, Julio Cesar´ Mar´ınc and Sandor´ Barand aDepartment of Statistics, University of Valpara´ıso Gran Breta~na1111, Valpara´ıso,Chile bFaculty of Engineering, Andres Bello University Quillota 980, Vi~nadel Mar, Chile cDepartment of Meteorology, University of Valpara´ıso Gran Breta~na644, Valpara´ıso,Chile dFaculty of Informatics, University of Debrecen Kassai ´ut26, H-4028 Debrecen, Hungary Abstract Currently all major meteorological centres generate ensemble forecasts using their operational ensemble prediction systems; however, it is a general problem that the spread of the ensemble is too small, resulting in underdispersive forecasts, leading to a lack of calibration. In order to correct this problem, different statistical calibration techniques have been developed in the last two decades. In the present work different post-processing techniques are tested for calibrating arXiv:1809.04042v1 [stat.AP] 11 Sep 2018 9 member ensemble forecast of temperature for Santiago de Chile, obtained by the Weather Research and Forecasting (WRF) model using different planetary boundary layer and land surface model parametrization. In particular, the ensemble model out- put statistics (EMOS) and Bayesian model averaging techniques are implemented and since the observations are characterized by large altitude differences, the estimation of model parameters is adapted to the actual conditions at hand. Compared to the raw ensemble all tested post-processing approaches significantly improve the calibration of probabilistic and the accuracy of point forecasts. The EMOS method using parameter estimation based on expert clustering of stations (according to their altitudes) shows the best forecast skill.
    [Show full text]
  • Statistical Postprocessing of Ensemble Forecasts for Severe Weather at Deutscher Wetterdienst
    Nonlin. Processes Geophys., 27, 473–487, 2020 https://doi.org/10.5194/npg-27-473-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Statistical postprocessing of ensemble forecasts for severe weather at Deutscher Wetterdienst Reinhold Hess Deutscher Wetterdienst, Offenbach, Germany Correspondence: Reinhold Hess ([email protected]) Received: 7 January 2020 – Discussion started: 20 January 2020 Revised: 13 August 2020 – Accepted: 19 August 2020 – Published: 6 October 2020 Abstract. This paper gives an overview of Deutscher Wet- 1 Introduction terdienst’s (DWD’s) postprocessing system called Ensemble- MOS together with its motivation and the design con- Ensemble forecasting rose with the understanding of the lim- sequences for probabilistic forecasts of extreme events ited predictability of weather. This limitation is caused by based on ensemble data. Forecasts of the ensemble systems sparse and imperfect observations, approximating numerical COSMO-D2-EPS and ECMWF-ENS are statistically opti- data assimilation and modelling, and by the chaotic phys- mised and calibrated by Ensemble-MOS with a focus on se- ical nature of the atmosphere. The basic idea of ensemble vere weather in order to support the warning decision man- forecasting is to vary observations, initial and boundary con- agement at DWD. ditions, and physical parameterisations within their assumed Ensemble mean and spread are used as predictors for lin- scale of uncertainty and rerun the forecast model with these ear and logistic multiple regressions to correct for conditional changes. biases. The predictands are derived from synoptic observa- The obtained ensemble of forecasts expresses the distribu- tions and include temperature, precipitation amounts, wind tion of possible weather scenarios to be expected.
    [Show full text]
  • Articles Described by the Community Multiscale Air Datasets, Moderate-To-Large Biases Exist in Hourly Precipita- Quality Modeling System
    Geosci. Model Dev., 14, 3969–3993, 2021 https://doi.org/10.5194/gmd-14-3969-2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Evaluation of the offline-coupled GFSv15–FV3–CMAQv5.0.2 in support of the next-generation National Air Quality Forecast Capability over the contiguous United States Xiaoyang Chen1, Yang Zhang1, Kai Wang1, Daniel Tong2,6, Pius Lee4,3, Youhua Tang3,4, Jianping Huang5,6, Patrick C. Campbell3,4, Jeff Mcqueen5, Havala O. T. Pye7, Benjamin N. Murphy7, and Daiwen Kang7 1Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA 2Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, VA 22030, USA 3Center for Spatial Information Science and System, George Mason University, Fairfax, VA 22030, USA 4Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA 5National Oceanic and Atmospheric Administration/National Centers for Environmental Prediction/Environmental Modeling Center, College Park, MD 20740, USA 6IM Systems Group, Rockville, MD 20852, USA 7Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA Correspondence: Yang Zhang ([email protected]) Received: 11 August 2020 – Discussion started: 2 September 2020 Revised: 19 January 2021 – Accepted: 7 February 2021 – Published: 29 June 2021 Abstract. As a candidate for the next-generation National Teorological Aerodrome Reports (METAR) dataset.
    [Show full text]
  • Performance Assessment of General Circulation Model in Simulating Daily Precipitation and Temperature Using Multiple Gridded Datasets
    water Article Performance Assessment of General Circulation Model in Simulating Daily Precipitation and Temperature Using Multiple Gridded Datasets Najeebullah Khan 1,2, Shamsuddin Shahid 1 , Kamal Ahmed 1,2, Tarmizi Ismail 1 , Nadeem Nawaz 2 and Minwoo Son 3,* 1 School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru, Malaysia; [email protected] (N.K.); [email protected] (S.S.); [email protected] (K.A.); [email protected] (T.I.) 2 Faculty of Water Resource Management, Lasbela University of Agriculture Water and Marine Sciences (LUAWMS), 90150 Uthal, Balochistan, Pakistan; [email protected] 3 Department of Civil Engineering, Chungnam National University, Daejeon 34134, Korea * Correspondence: [email protected]; Tel.: +82-42-821-5676 Received: 28 September 2018; Accepted: 4 December 2018; Published: 6 December 2018 Abstract: The performance of general circulation models (GCMs) in a region are generally assessed according to their capability to simulate historical temperature and precipitation of the region. The performance of 31 GCMs of the Coupled Model Intercomparison Project Phase 5 (CMIP5) is evaluated in this study to identify a suitable ensemble for daily maximum, minimum temperature and precipitation for Pakistan using multiple sets of gridded data, namely: Asian Precipitation– Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE), Berkeley Earth Surface Temperature (BEST), Princeton Global Meteorological Forcing (PGF) and Climate Prediction Centre (CPC) data. An entropy-based robust feature selection approach known as symmetrical uncertainty (SU) is used for the ranking of GCM. It is known from the results of this study that the spatial distribution of best-ranked GCMs varies for different sets of gridded data.
    [Show full text]
  • Guidelines on Ensemble Prediction System Postprocessing
    Guidelines on Ensemble Prediction System Postprocessing 2021 edition WEATHER CLIMATE WATER CLIMATE WEATHER WMO-No. 1254 Guidelines on Ensemble Prediction System Postprocessing 2021 edition WMO-No. 1254 WMO-No. 1254 © World Meteorological Organization, 2021 The right of publication in print, electronic and any other form and in any language is reserved by WMO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to: Chair, Publications Board World Meteorological Organization (WMO) 7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03 P.O. Box 2300 Fax: +41 (0) 22 730 81 17 CH-1211 Geneva 2, Switzerland Email: [email protected] ISBN 978-92-63-11254-5 NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised. PUBLICATION REVISION TRACK RECORD Part/chapter/ Date Purpose of amendment Proposed by Approved by section CONTENTS Page ACKNOWLEDGEMENTS . vii EXECUTIVE SUMMARY . viii KEY RECOMMENDATIONS . ix CHAPTER 1 . INTRODUCTION . 1 CHAPTER 2 . PHYSICAL POSTPROCESSING . 5 2.1 Meteorological diagnostic information.
    [Show full text]
  • A Model Output Deep Learning Method for Grid Temperature Forecasts in Tianjin Area
    applied sciences Article A Model Output Deep Learning Method for Grid Temperature Forecasts in Tianjin Area Keran Chen 1,2 , Ping Wang 1,2, Xiaojun Yang 3, Nan Zhang 3 and Di Wang 1,2,* 1 School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, China; [email protected] (K.C.); [email protected] (P.W.) 2 Joint Laboratory of Intelligent Identification & Nowcasting Service for Convective System, CMA Public Meteorological Service Center, Beijing 100081, China 3 Tianjin Bureau of Meteorology, Tianjin 300074, China; [email protected] (X.Y.); [email protected] (N.Z.) * Correspondence: [email protected] Received: 25 June 2020; Accepted: 18 August 2020; Published: 22 August 2020 Abstract: In weather forecasting, numerical weather prediction (NWP) that is based on physical models requires proper post-processing before it can be applied to actual operations. Therefore, research on intelligent post-processing algorithms has always been an important topic in this field. This paper proposes a model output deep learning (MODL) method for post-processing, which can improve the forecast effect of numerical weather prediction. MODL is an end-to-end post-processing method based on deep convolutional neural network, which directly learns the mapping relationship between the forecast fields output by numerical model and the observation temperature field in order to obtain more accurate temperature forecasts. MODL modifies the existing deep convolution model according to the post-processing problem’s characteristics, thereby improving the performance of the weather forecast. This paper uses The International Grand Global Ensemble (TIGGE) dataset from European Centre for Medium-Range Weather Forecasts (ECMWF) and the observed air temperature of 2 m obtained from Tianjin meteorological station in order to test the post-processing performance of MODL.
    [Show full text]
  • SCN21-21 Updated: Notification of Dissemination Changes of Models Downstream of the GFS Due To
    NOUS41 KWBC 181800 AAA PNSWSH Service Change Notice 21-21 Updated National Weather Service Headquarters Silver Spring MD 200 PM EDT Thu Mar 18 2021 To: Subscribers: -NOAA Weather Wire Service -Emergency Managers Weather Information Network -NOAAPort Other NWS Partners, Users and Employees FROM: Mike Farrar Director National Centers for Environmental Prediction SUBJECT: Updated: Notification of Dissemination Changes of Models Downstream of the GFS due to the GFSv16 Upgrade: Effective March 22, 2021 Updated to reflect delay in implementation date to Monday, March 22 due to Critical Weather Day. Effective on or about March 22, 2021, beginning with the 1200 Coordinated Universal Time (UTC) cycle of the Global Forecast System (GFS), models that use GFS products for initialization will experience delays associated with the upgrade to GFS V16. Due to timing changes with the GFSv16 upgrade, which are laid out in its own SCN, the following downstream models will have timing changes across all dissemination channels including AWIPS, Satellite Broadcast Network(SBN)/NOAAPort, and NCEP and NWS web services (NOMADS, NOMADS GDS, NOMADS grib filter, FTPPRD and TGFTP). Ensemble Tracker: up to 16 min later https://nomads.ncep.noaa.gov/pub/data/nccf/com/ens_tracker/prod/ ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/ens_tracker/prod/ Extra-Tropical Storm Surge (ETSS): up to 10 min later https://nomads.ncep.noaa.gov/pub/data/nccf/com/etss/prod/ ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/etss/prod/ https://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT
    [Show full text]
  • Generalizing Model Output Statistics with Recurrent Neural Networks
    Generalizing Model Output Statistics With Recurrent Neural Networks Joan Creus-Costa Departments of Computer Science and Physics Stanford University [email protected] Abstract We present an architecture using a single neural network to learn a mapping between the raw outputs of a numerical prediction model and model output statistics of interest, in this case temperature and dewpoint temperature. Instead of learning a model for each of thousands of weather stations, we enable data reuse and better learning by using a single recurrent neural network that learns the biases based on the errors of the model in the previous days. This greater generalization enables for better adaptation to changes in NWP models and makes it easier to add new locations for which predictions of model output statistics are desired. It achieves comparable performance to NOAA’s state of the art model output statistics, with a root-mean-square error of 1.88 and 1.70 degrees Celsius in predicting temperature and dewpoint 24 hours in advance. 1 Introduction Global numerical weather prediction models, such as the American GFS or the European ECMWF, produce outputs for various variables—such as humidity or temperature—on a coarse grid with a resolution of approximately 27 km. These raw forecasts, however, do not directly translate to weather forecasts as we know them. The issue with them is threefold: one, it does not capture all the variables humans care about (such as probability of rain, or surface-level quantities); second, it can have a variety local and global biases and systematics; and thirdly, its limited resolution means interpolation is required to produce predictions of meaningful quantities at the points of interest [1].
    [Show full text]