The Australian Wind Profiler Network

Transcription

1 The Australian Wind Profiler Network Bronwyn Dolman 1,2, Iain Reid 1,2, Chris Tingwell 3 and Tom Kane 3 1 ATRAD Pty Ltd 20 Phillips St Thebarton South Australia www. 2 University of Adelaide, Australia 3 Australian Government Bureau of Meteorology

2 Australian Profiler Network Carnarvon Tennant Creek Davis Station Buckland Park Ceduna

3 Australian Profiler Network Complement existing meteorological technology providing continuous profiles of the atmosphere in the vertical column above the instrument Tennant Creek Weather Radar Wind Profiling Radar Remote Balloon Launcher Meteorological Instrumentation

4 Australian Profiler Network Currently all VHF systems (55 MHz) Boundary Layer Profiler (BLP) 8 km coverage Stratospheric Tropospheric Profiler (STP) 20 km coverage Transceiver / System design is modular signal processing with most components shared Combiner Antennas Beam Steering Power Amplifiers 80 kw STP

5 Boundary Layer Profilers Spaced Antenna Full Correlation Analysis 27 Yagi antennas arranged in 3 groups of spacing BLP Frequency Power Receiver Acquisition 55 MHz (range MHz) 12 kw (3 4 kw modules) 3 coherent (complex) channels Virtex 4 FPGA

6 Boundary Layer Profilers Spaced Antenna Full Correlation Analysis 27 Yagi antennas arranged in 3 groups of spacing Low High Pulse Width 100 m 500 m PRF Hz Hz Range 0 7 km 0 14 km Sampling Interval 100 m 250 m Dwell Time 55 s 55 s Coherent Integrations Spectral Points

7 Stratospheric Tropospheric Profilers Doppler Beam Steering Analysis 144 Yagi antennas arranged on a 12 x 12 square grid 0.7 spacing Phase delays to steer beam STP Frequency Power Receiver Acquisition 55 MHz (range MHz) 80 kw (24 4 kw modules) 3 coherent (complex) channels (1 used) Virtex 4 FPGA

8 Stratospheric Tropospheric Profilers Doppler Beam Steering Analysis 144 Yagi antennas arranged on a 12 x 12 square grid 0.7 spacing Phase delays to steer beam Low High Pulse Width 250 m 1000 m PRF Hz 6000 Hz Range 0 8 km 1 20 km Sampling Interval 100 m 200 m Dwell Time 55 s (per beam) 55 s (per beam) Coherent Integrations Spectral Points

9 Wind Measurements Doppler FCA X 15 Averaging interval: 30 mins

10 Wind Measurements Doppler Quality Control FCA X 15 Quality Control Averaging interval: 30 mins

11 Wind Measurements Doppler Quality Control Wind Estimate FCA X 15 Quality Control Wind Estimate Averaging interval: 30 mins

12 Wind Measurements Doppler Quality Control Wind Estimate BUFR FCA X 15 Quality Control Wind Estimate BUFR Averaging interval: 30 mins

13 Wind Measurements Doppler Quality Control Wind Estimate BUFR Output to user FCA X 15 Quality Control Wind Estimate BUFR Averaging interval: 30 mins

14 Wind Measurements Verified at each site against sondes Zonal and meridional comparison Sonde magnitude against profiler

15 Forecasters 30 minute average data available to Australian forecasters Gradient and steering winds, jet onset time and duration Aviation forecasts Fire weather 20 km Tennant Creek 80 kw STP high mode

16 Global data use Most BoM profilers now available on EUMETNET wind profilers

17 ACCESS NWP Courtesy of Chris Tingwell BoM Based on Met Office Unified Model and 4D Var data assimilation Provides the BoM with operational forecasts Global and Regional ACCESS systems assimilate a wide range of meteorological observations in six hour cycles

18 ACCESS Forecast Sensitivity to Observations Courtesy of Chris Tingwell BoM Observations Data Assimilation 4D Var model Forecast T + 24h Analysis Forecast error T + 24h Significant new technique in which the forecast error reduction in a 24 hour forecast due to data assimilation can be split up and attributed to each individual assimilated observation. Change in forecast error due to each observation Adjoint VAR Change in forecast error due to analysis model Adjoint PF model Forecast T + 30h Change in forecast error Forecast error T + 30h Forecast error is measured by a global energy norm (in J/kg). Over several weeks, the reduction of forecast error due to observing systems, instruments, groups of observations etc. can be aggregated and compared.

19 Australian Upper Air Observing Network Courtesy of Chris Tingwell BoM Halls Creek WINPRO & PILOT TEMP: radiosonde observations of temperature, moisture, wind (once/twice per day) PILOT: tracked balloon flights wind only (once/twice per day) WINPRO: wind profilers (hourly) Williamtown Sydney Labelled stations used for comparisons here

20 Courtesy of Chris Tingwell BoM Australian Upper Air Observing Network Forecast Impact/day (J/kg) 24 hour forecast error reduction in the global ACCESS system due to observations in the Australian Upper Air network aggregated over 10 weeks (more negative means more forecast error reduction). Wind profilers contribute less than the impact of the radiosonde "TEMP" observations, but rather more than the "PILOT" wind observations. WINPRO observation impacts are less on a per observation basis (2 nd panel) but this is counter balanced by their being much more frequent. Forecast Impact/observation (J/kg)

21 Courtesy of Chris Tingwell BoM Australian Upper Air Observing Network Forecast Impact/day (J/kg) Temp impacts greatest as include measurements of temperature, humidty and wind reported at many observation levels. Also assigned a smaller observation error in the assimilation and is thus assigned more weighting. Per observation refers to, say, a single zonal wind measurement at a particular height at a particular time. Density and timing of observation must be considered here. The profilers are typically located at Bureau sites and thus amidst other observations. The sondes are at a lower temporal resolution and thus add information to a region of the model which hasn t seen an observation for up to 24 hours. Forecast Impact/observation (J/kg)

22 Australian Upper Air Observing Network Forecast Impact/day (J/kg) Williamtown v. Sydney Courtesy of Chris Tingwell BoM Comparison of impacts from nearby radiosonde "TEMP" (Williamtown) and Wind profiler (Sydney) observations. The greatest impact/observation is from the Williamtown temperature & moisture measurements, but the aggregated forecast impact from the Sydney wind profiler is almost as much as from the Williamtown radiosonde flights. Forecast Impact/observation (J/kg)

23 Australian Upper Air Observing Network Forecast Impact/day (J/kg) Halls Creek Courtesy of Chris Tingwell BoM Co located wind profiler and PILOT observations PROFILER: hourly observations throughout day. PILOT balloon flights: twice a day at 00 UTC & 06 UTC. WINPRO observations have greater integrated forecast impact because of much greater numbers, although the impact per observation is less. Forecast Impact/observation (J/kg)

24 Current Developments Examining dwell time with an aim to reduce it Turbulence estimates Tropopause detection Developing real time automatic peak detection routines Automatically identify and where possible or problematic, remove interference Trigger additional analysis such as precipitation retrievals Alexander, S. P., Murphy, D. J. and Klekociuk, A. J., High resolution VHF radar measurements of tropopause structure and variability at Davis, Antarctica (69 o S, 78 o E), Atmos. Chem. Phys., 13, 3121, 3132, 2013

25 Interference Removal Courtesy of Baden Gilbert UoA Aircraft interference

26 Interference Removal Courtesy of Baden Gilbert UoA Aircraft interference

27 Real Time Retrievals Precipitation Rainfall Clear air

28 Real Time Retrievals Precipitation Drop Size Distribution Rainfall Clear air

29 Real Time Retrievals Precipitation Drop Size Distribution Rain Rate Retrieval Rainfall Clear air

30 Conclusion Australian wind profiler network consists of 18 instruments across Australia and Antarctica 11 assimilated profilers make a significant contribution to improving the forecast skill of ACCESS Current effort geared towards providing the best possible product for the user, and utilising data for more than wind estimates