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Radar data from cold air outbreak during Constrain

Radar data from cold air outbreak during Constrain. Kirsty McBeath. Introduction. Looking at cases of cold air outbreak in the Northwest approaches 4 flights during Constrain examined these conditions during January 2010 Radar data from these cases used for comparisons with UKV model

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Radar data from cold air outbreak during Constrain

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  1. Radar data from cold air outbreak during Constrain Kirsty McBeath

  2. Introduction • Looking at cases of cold air outbreak in the Northwest approaches • 4 flights during Constrain examined these conditions during January 2010 • Radar data from these cases used for comparisons with UKV model • This data is from a case on January 31st 2010 which coincides with flight b507 of the BAe-146 research aircraft MODIS 31st Jan 2010

  3. Overview of observations

  4. Position of radar Druim-A-Starraig radar 300km 300km

  5. Data from radar • Data available every 5 minutes for 24 period • Using data at 15min intervals for 4.5h period to correspond to model • Scans performed at a range of angles: 0.5°, 1.0°, 1.5°, 2.5° • Data up to height of 12km • More observations close to the surface and close to the radar due to beam overlap

  6. Model Radar Cloud microphysics fields in model used to forward model reflectivity values

  7. Cluster analysis

  8. Cluster Analysis Radar Model 10dBz threshold used to select regions of precipitation (~4mm/day) in both datasets

  9. Cluster Analysis • Identified cells tracked in time for both datasets • Cells excluded from dataset if they moved outside the region of interest, or were only seen to decay • 75 cells identified in observations (+109 excluded cells) • 42 cells identified in model data (+59 excluded cells)

  10. Cluster size Both datasets have same mode in size distribution Model has fewer large cells than radar observations Much greater spread in sizes seen in radar data

  11. Cell size with time

  12. Maximum size Model also has much less spread than observations in the maximum cell size reached

  13. Cluster lifetime Model has more cells with short lifetimes than are seen in the observations

  14. Cluster growth

  15. Cluster Growth Rate

  16. Reflectivity with cell lifetime Model data has higher cell reflectivity values and more variation in cell reflectivity throughout cell lifetime

  17. Cells encountered by the BAe-146 19 cells intercepted by BAe-146 during b507 Mean cell size = 15.7km (s = 9.04km) Mean (full dataset) = 12.06km (s = 7.25km)

  18. Cells encountered by the BAe-146 Cells intercepted by aircraft are slightly larger and longer-lived than average

  19. Next steps Repeat this analysis for different model configurations Look at impact of using different reflectivity thresholds for cluster analysis Examine model data with higher spatial and temporal resolution Compare data from radar and model with data from the 146 research aircraft

  20. Questions

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