Papers by John Le Marshall
The Japanese Meteorological Agency (JMA) launched the geostationary satellite Himawari-8 in Octob... more The Japanese Meteorological Agency (JMA) launched the geostationary satellite Himawari-8 in October 2014. The satellite provides 10 minute, sixteen band imagery over the Asian and Australasian region. The imagery has been navigated, calibrated and subsequently used in the Bureau of Meteorology (BoM) to generate Atmospheric Motion Vectors (AMVs) over the full earth disk viewed from the satellite every ten minutes. Each vector has been error characterised and assigned an expected error. In preparation for the operational assimilation of the 10-minute data, these high temporal and spatial resolution data were used in the BoM test operational database to provide forecasts from the next generation operational forecast model ACCESS APS2 using 4D Var. Results from these tests indicate these locally generated Himawari-8 10 minute AMVs are of high quality and density and have the potential to improve numerical weather prediction (NWP) model initialisation and forecasts. The forecasts underta...
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An Analysis Of The Impact Of Earth Observations From Space On Australian And Global Numerical Wea... more An Analysis Of The Impact Of Earth Observations From Space On Australian And Global Numerical Weather Prediction. John Le Marshall(1,3), Jin Lee(1), Paul Gregory(1) Jim Jung(2), Robert Norman(3), and Rolf Seecamp(1). (1) Bureau of Meteorology, Australia, (2) Joint Center for Satellite Data Assimilation, USA, (3) RMIT University, Melbourne, Australia Earth observations from space (EOS), taken by advanced instruments on current and future satellite missions will increasingly provide large volumes of data related to Earth System State. Key benefits from assimilating these earth observations, particularly from an Australian Region and southern hemisphere perspective have been documented. The benefits described are in relation to synoptic scale and severe weather forecasts. Instruments providing these benefits include the Atmospheric Infrared Sounder, those carried by the COSMIC Constellation and the GOES and MTSAT imager. Examples of the beneficial impact of these data are provided. Man...
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Bureau Research Report, 2016
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Journal of Southern Hemisphere Earth System Science, 2017
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Australian Meteorological and Oceanographic Journal, 2010
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Data from the Japanese geostationary satellite MTSAT -1R (and at times MTSAT-2) have been receive... more Data from the Japanese geostationary satellite MTSAT -1R (and at times MTSAT-2) have been received at the Bureau of Meteorology (BoM) satellite groundstation at Crib Point, Victoria. Calibrated and navigated sequential radiance data have been subsequently used to calculate high density Atmospheric Motion Vectors (AMVs). These AMVs have been generated almost continuously throughout the day using sequential images separated by 15-minutes, 30 minutes or an hour. The winds have been calculated using infrared (11 µm), (high resolution) visible (0.5 µm) and water vapour absorption (6.7 µm) band images. The AMVs have been error characterized with error characteristics including the correlated error, the length scale of the correlated error, the Expected Error and Quality Indicator being estimated. These AMV data are important for operational NWP, research and particularly for severe weather forecasting, including tropical cyclone track forecasting. The data have been used in real time data...
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Procedia Earth and Planetary Science, 2009
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Weather and Forecasting, 2013
Atmospheric motion vectors (AMVs) have been generated continuously from Multifunctional Transport... more Atmospheric motion vectors (AMVs) have been generated continuously from Multifunctional Transport Satellite 1 Replacement (MTSAT-1R) radiance data (imagery) since 2005, and more recently from MTSAT-2, which are operated by the Japan Meteorological Agency (JMA). These are the primary geostationary meteorological satellites observing the western Pacific, Asia, and the Australian region. The vectors are used operationally, for analysis in the Darwin Regional Forecast Office. The near-continuous AMVs have been stringently error characterized and used in near-real-time trials to gauge their impact on operational regional numerical weather prediction (NWP), using four-dimensional variational data assimilation (4DVAR). The use of these locally generated hourly vectors (the only hourly AMV source in the region at the time) and 4DVAR has resulted in both improved temporal and spatial data coverage in the operational regional forecast domain. The beneficial impact of these data on the Bureau ...
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Weather and Forecasting, 2008
Observing system experiments (OSEs) during two seasons are used to quantify the important contrib... more Observing system experiments (OSEs) during two seasons are used to quantify the important contributions made to forecast quality from the use of the National Oceanic and Atmospheric Administration’s (NOAA) polar-orbiting satellites. The impact is measured by comparing the analysis and forecast results from an assimilation–forecast system using one NOAA polar-orbiting satellite with results from using two and three polar-orbiting satellites in complementary orbits. The assimilation–forecast system used for these experiments is the National Centers for Environmental Prediction (NCEP) Global Data Assimilation System–Global Forecast System (GDAS–GFS). The case studies chosen consist of periods during January–February and August–September 2003. Differences between the forecasts are accumulated over the two seasons and are analyzed to demonstrate the impact of these satellites. Anomaly correlations (ACs) and geographical forecasts (FIs) are evaluated for all experimental runs during both ...
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Monthly Weather Review, 2011
A two-season Observing System Experiment (OSE) was used to quantify the impacts of assimilating t... more A two-season Observing System Experiment (OSE) was used to quantify the impacts of assimilating the Advanced Scatterometer (ASCAT) surface winds product distributed by the European Organization for the Exploitation of Meteorological Satellites (EUMESAT) and the National Environmental Satellite, Data, and Information Service (NESDIS). The ASCAT wind retrievals were provided by the Royal Netherlands Meteorological Office (KNMI) and the 50-km resolution ASCAT products were assimilated. The impact of assimilating the ASCAT surface wind product in the National Centers for Environmental Prediction (NCEP) Global Data Assimilation/Global Forecast System (GDAS/GFS) was assessed by comparing the forecast results through 168 h for the months of August 2008 and January 2009. The NCEP GDAS/GFS was used, at a resolution of T382–64 layers, as the assimilation system and forecast model for these experiments. A control simulation utilizing all the data types assimilated in the operational GDAS was c...
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5th WMO Data …, 2009
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Atmospheric Research, 2014
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Journal of Southern Hemisphere Earth System Science, 2019
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Journal of Southern Hemisphere Earth Systems Science, 2019
The use of high spatial and temporal resolution data assimilation and forecasting around Australi... more The use of high spatial and temporal resolution data assimilation and forecasting around Australia’s capital cities and rural land provided an opportunity to improve moisture analysis and forecasting. To support this endeavour, RMIT University and Geoscience Australia worked with the Bureau of Meteorology (BoM) to provide real-time GNSS (global navigation satellite system) zenith total delay (ZTD) data over the Australian region, from which a high-resolution total water vapour field for SE Australia could be determined. The ZTD data could play an important role in high-resolution data assimilation by providing mesoscale moisture data coverage from existing GNSS surface stations over significant areas of the Australian continent. The data were used by the BoM’s high-resolution ACCESS-C3 capital city numerical weather prediction (NWP) systems, the ACCESS-G3 Global system and had been used by the ACCESS-R2-Regional NWP model. A description of the data collection and analysis system is ...
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In 2010, an international consortium led by the SPACE Research Centre, RMIT University was awarde... more In 2010, an international consortium led by the SPACE Research Centre, RMIT University was awarded a prestigious Australian Space Research Program (ASRP). This project formed part of the Australian Government's latest space-related initiatives to support national strategic, economic and social objectives, and to enhance Australia's space capabilities by developing integrated and advanced space-based platform technologies through a multi-sensor satellite remote sensing approach. The issues and challenges confronting Australian space research and space industry will be discussed. The research tasks and outcomes for this project will be presented. The research tasks in the context of GPS Radio Occultation (RO) include the analysis of ionospheric errors and developing new methods for statistical optimization for better quality atmospheric retrievals, study of ionospheric scintillation and simulation of ray tracing of GPS RO signal paths and their innovative applications in the a...
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Journal of the Meteorological Society of Japan. Ser. II, 1997
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Papers by John Le Marshall