1 / 17

Refractivity in the Coastal Atmospheric Boundary Layer

Refractivity in the Coastal Atmospheric Boundary Layer. Stephen Burk and Tracy Haack Naval Research Laboratory Monterey, CA. Strength (  M). Height. top. Thickness (= top-base). base. Modified Refractivity, M. Refractivity in the Coastal Atmospheric Boundary Layer. . Q. Height.

kelii
Download Presentation

Refractivity in the Coastal Atmospheric Boundary Layer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Refractivity in the Coastal Atmospheric Boundary Layer Stephen Burk and Tracy Haack Naval Research Laboratory Monterey, CA

  2. Strength (M) Height top Thickness (= top-base) base Modified Refractivity, M Refractivity in the Coastal Atmospheric Boundary Layer  Q Height Potential Temperature & Specific Humidity

  3. COAMPSTM 27km grid SAUDI ARABIA INDIA Cook & Burk, 1992, BLM, 58, 151-159. Burk & Thompson, 1997, JAM, 36, 22-31. Haack & Burk, 2001, JAM, 40, 673-687. Burk, Haack, Rogers, & Wagner, 2003, JAM, 349-367.

  4. Wallops 2000 EM Propagation Field Experiment from NSWCDD/TR-01/132

  5. DMDZ/THETA Height (m) COAMPSTM Wallops Island DTG: 10-12 Apr 2000 Triple nest: 27-9-3 km Vertical: 40 levels SST/SLP 10-m Winds/SLP x = 3 km x = 27 km

  6. April 10, 2000 1200 UTC April 12, 2000 1200 UTC April 11, 2000 1200 UTC

  7. Dots = COAMPSTM forecast values EDH(m) RH(%) Ta T(0C) IR U(m/s) Obs from Davidson, NPS

  8. Wallops * Norfolk COAMPSTM SST and Ground Temperature * 284 297 3 am LT 10 Apr 2000

  9. 20 20 0 0 0 -20 0 0 40 0 0 40 -20 20 0 20 60 60 COAMPSTM Sensible Heat Flux (W/m2); near surface streamlines 11 Apr 2000 3 am LT 3 pm LT

  10. 2 6 10 8 4 12 4 24 28 COAMPSTM Evaporation Duct Height (m) 11 Apr 2000 3 am LT 3 pm LT

  11. Strength (M) Height top base Modified Refractivity, M Animation of two 24h COAMPSTM forecasts of: 40m(shaded); 50m streamlines; & dM/dz = 0 isosurface (white) hourly fields from 00 UTC 11 Apr- 2300 UTC 12 Apr 2000

  12. North South 1 km 0 Horizontal: Evaporation Duct Height (shaded) & Streamlines Vertical: Potential Temperature (shaded & contoured) “Clouds”: Trapping Layer (DMDZ=0 isosurface)

  13. (a) (b) M Crossection M Crossection Shaded with dM/dz (c) Looking toward SE across Tidewater Peninsula Red Isosurface  dM/dz = 157 M-units/km  subrefraction White isosurface  dM/dz = 0 M-units/km  trapping layer 1800 UTC 12 Apr 2000 COAMPSTM

  14. 1800 UTC 12 Apr 2000 COAMPSTM Mixing Ratio (g/kg), Shaded; Potential Temperature (K),contoured

  15. Duct parameters from COAMPSTM 1800 UTC 12 Apr 2000 Wallops Island 500 400 300 18 15 300 200 12 200 9 100 100 6 0 3 0 0 Duct Base Height (m) Duct Thickness (m) Duct Strength (M-units)

  16. Summary • COAMPSTM forecasts both evaporation ducts and elevated and/or • surface based ducts • To date, most modeling studies of refractivity/propagation have focused on • subsidence dominated, strongly capped BL’s (e.g., CA coast in summer; • Persian Gulf) • Intensive Observation Periods of the Wallops-2000 propagation field experiment • are addressed here using COAMPSTM at high resolution. Model refractivity • will be inserted into propagation codes for comparison with prop measurements. • New insights into refractivity structure in frontal regions are emerging • Accurate forecasting of major synoptic features (e.g., frontal boundaries) can be • of greater importance than extremely high model resolution in defining local • refractive structure/ EM propagation conditions. Mesoscale ensembles may • be very useful in this context.

More Related