Australian Wind Profiler Network and Data Use in both Operational and Research Environments

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1 Australian Wind Profiler Network and Data Use in both Operational and Research Environments Bronwyn Dolman 1,2 and Iain Reid 1,2 1 ATRAD Pty Ltd 20 Phillips St Thebarton South Australia 2 University of Adelaide, Australia

2 Introduction Tennant Creek, Australia Weather Radar Wind Profiling Radar Remote Balloon Launcher Meteorological Instrumentation

3 Operational Profilers Complement existing meteorological technology by providing continuous profiles of the atmosphere in the vertical column above the instrument Principal operation, as the name suggests, is to profile the horizontal and vertical wind 20 km 0 km South Uist 40 kw STP high mode 12 UT 00 UT 24 UT

4 Operational Profilers Wind profiling radars sample the atmosphere in the vertical column above the instrument Transmit pulsed RF, which scatters from various atmospheric constituents Calculate height of returns from time delay Height Targets Time

5 Operational Profilers Targets depend on profiler frequency. For VHF & UHF: Rayleigh scatter from clear air irregularities in pressure, temperature and humidity Bragg scatter from precipitation As the frequency increases, sensitivity to clear-air decreases and to precipitation increases Height Targets Time

6 Australian Profiler Network Carnarvon Tennant Creek

7 Australian Profiler Network Carnarvon Tennant Creek Ceduna

8 Australian Profiler Network Carnarvon Tennant Creek Ceduna

9 Australian Profiler Network Carnarvon Tennant Creek Ceduna

10 Australian Profiler Network Carnarvon Tennant Creek Ceduna

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

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

13 World wide installations MF radar VHF boundary layer radar VHF stratosphere-troposphere radar VHF meteor detection radar Broadband radar VHF Ionospheric radar Other

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

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

16 Boundary Layer Profilers Spaced Antenna Full Correlation Analysis 27 Yagi antennas arranged in 3 groups of λ 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

17 Scatter plot of Ceduna wind magnitude (vertical) against radiosondes (horizontal) launched from the same location. The histogram shows the difference between the sonde and profiler. Results from a three year validation. Boundary Layer Profilers Ceduna 12 kw BLP validation

18 Stratospheric Tropospheric Profilers Doppler Beam Steering Analysis 144 Yagi antennas arranged on a 12 x 12 square grid 0.7 λ 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

19 Stratospheric Tropospheric Profilers Doppler Beam Steering Analysis 144 Yagi antennas arranged on a 12 x 12 square grid 0.7 λ 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

20 Wind Measurement Process

21 Wind Measurement Process

22 Wind Measurement Process

23 Wind Measurement Process

24 Wind Measurement Process

25 Wind Measurement Process

26 Wind Measurement Process

27 Wind Measurement Process

28 Wind Measurement Process Quality Control Quality Control Quality Control Quality Controlled Wind Estimate

29 Data use - ACCESS ACCESS NWP Australian Community Climate and Earth- System Simulator Model Domain Resolution ACCESS-G Global ~40 km ACCESS-R Regional ~12 km ACCESS-C City ~4 km ACCESS-TC Relocatable ~12 km

30 Data use - ACCESS BUFR Model observation processing system 6 hour resolution (higher temporal resolution for 1.5 km model) Quality Control Background and basic sanity checks Variational analysis with all other data

31 Data use - ACCESS Currently, only OS wind profilers are assimilated Most data EUMETNET Some North America Some Japan Typically receive observations per day, assimilate ~15%

32 Data use - ACCESS Data from Australian instruments has been analysed, and bias and variance observations with respect to ACCESS wind fields support data assimilation Next operational upgrade

33 Data use - forecasters Regional forecasting centre in each capital city Data use varies with location, expertise and individual preference Gradient winds for seabreeze and fog forecasting Steering winds in thunderstorms Aviation forecasts, particularly for ground-truthing models when deciding whether to issue a SIGMET Fire weather Convective analyses, steering winds in mid-levels are analysed as to direction developing convection will take

34 Data use - forecasters Data from each station at 800 hpa are plotted, and the forecasters interpretation of wind speed, wind direction and pressure systems are hand drawn on. These plots are then compared to numerical weather model output.

35 06 UT 18 UT Data use - forecasters TC low level jet seen most mornings during the dry season verifying forecasts of jet onset time and strength very important, particularly to aviation clients 8 km Tennant Creek 80 kw STP low mode

36 Data Availability 20 km UKMO South Uist 40 kw STP high mode Wind barbs plotted on the signal to noise ratio. Warm colours indicate higher SNRs. South Uist 40 kw STP high mode 15 km Each cell represents a single height and time. White indicates a wind was retrieved, red indicates no wind was available.

37 Data Availability 20 km Tennant Creek 80 kw STP high mode 800 days Bright green indicates 100% data availability, light blue is 80-89%.

38 800 days Data Availability 7 km Ceduna 12 kw BLP low mode 6 km Tennant Creek 80 kw STP low mode > 1000 days

39 UHF BL Motivation ST Profiler km 40 m x 40 m BL Profiler km 14 m x 14 m UHF Profiler 0.1 5* km 3 m x 3 m

40 UHF BL Motivation Need for a simple radar to sample the lowest km of the atmosphere Existing radar wind profiler technology does not typically perform well in the lowest part of the boundary layer (first 300 m of the atmosphere) Need for an easily deployable / relocatable radar For agriculture, bushfire weather, wind farms / wind prospecting A complement to existing ATRAD wind profiling products

41 UHF Preproduction Design Low power ~ 1.5 kw base Modular/scalable Increase the number of modules to increase the aperture, and therefore the height coverage Transmitter Scale power Deploy single modules at spatially relevant locations, to sample weather patterns of interest Capable of rapid deployment Receivers Back T/R switches Front

42 Potential Uses Weather forecasting Nowcasting Bushfire monitoring Environmental monitoring Mining Agriculture Educational tool Research Local weather effects Precipitation/frontal studies

43 Buckland Park 55 MHz ST antenna field 55 MHz ST electronics UHF antenna field 55 MHz BL & UHF electronics 55 MHz BL antenna field

44 Buckland Park Field Site Dish with Yagi as feed 3 x 3 x 3 Yagi array Original Yagi array Yagi array without radome or clutter screen

45 UHF Wind Retrievals Initial Field Trials with 600 W UHF 6 km 2 km 10 ms -1 Magnitude Direction 55 MHz VHF BL in blue, 449 MHz UHF BL with Yagi panel antennas in red. The difference in scattering mechanisms is clear, with the UHF retrieving winds where the VHF did not.

46 UHF Wind Retrievals Initial Field Trials with 600 W UHF 55 MHz VHF BL in blue, 449 MHz UHF BL with Yagi panel antennas in red. At this time the UHF and VHF show excellent agreement. 10 ms -1 Magnitude Direction

47 UHF Wind Retrievals UHF to VHF BLP validation Scatter plot of UHF wind magnitudes (vertical) against 55 MHz VHF wind magnitudes (horizontal) at Buckland Park. The histogram shows the difference between the VHF and UHF.

48 UHF BL Wind Retrievals 2.2 km BP 12 kw BLP low mode (top), 600 W UHF using Yagi panels (bottom) 2.2 km Wind barbs plotted on the Signal to Noise Ratio. Warm colours indicate higher SNRs.

49 UHF BL Wind Retrievals 2.2 km BP 12 kw BLP low mode (top), 600 W UHF using Yagi panels (bottom) 2.2 km Wind barbs plotted on the Signal to Noise Ratio. Warm colours indicate higher SNRs.

50 UHF Preproduction System Currently awaiting trial at Adelaide Airport 5 kw peak power available Refining antenna designs Optimising experiment parameters 5 kw system with front panels removed

51 Other Data Uses Precipitation Information Tropopause Detection Turbulence Monitoring Holdsworth, D. A., Vincent, R. A. and Reid, I. M., Mesospheric turbulent velocity estimation using the Buckland Park MF radar 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

52 Conclusion Well established VHF wind profilers UHF preproduction system in final stages of testing At smallest system size, the target is a system suitable for use as a network of low cost profilers At larger system sizes, the targets are BL and ST equivalents at higher frequencies than our 55 MHz systems (spectrum allocations vary worldwide) Data use Operational: forecasts and models Wind field mapping: forecasting and climatologies Research: e.g., low level jets, wave effects DSD retrievals: QPE and microphysics