1 / 17

Applications of Radar Refractivity Retrievals: Two-Year Climatology of Boundary Layer Moisture

Applications of Radar Refractivity Retrievals: Two-Year Climatology of Boundary Layer Moisture . David Bodine, Pamela L. Heinselman, Robert D. Palmer, Boon Leng Cheong, Dan Michaud School of Meteorology and Atmospheric Radar Research Center Graduate Student University of Oklahoma.

keiji
Download Presentation

Applications of Radar Refractivity Retrievals: Two-Year Climatology of Boundary Layer Moisture

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. Applications of Radar Refractivity Retrievals: Two-Year Climatology of Boundary Layer Moisture David Bodine, Pamela L. Heinselman, Robert D. Palmer, Boon Leng Cheong, Dan Michaud School of Meteorology and Atmospheric Radar Research CenterGraduate StudentUniversity of Oklahoma Acknowledgements: Support for this research was provided by the Radar Operations Center, National Science Foundation, and the American Meteorological Society Fellowship Program.

  2. Motivation Problem: One of the greatest challenges in meteorology is convective weather forecasting (Emanuel et al. 1995) Example: QPF convective weather forecasts are worst in summer Reason: Limited temporal and spatial resolution of moisture measurements hinders accuracy of convective weather forecasts

  3. Radar Refractivity • Technique that uses ground clutter phase measurements to obtain refractivity (Fabry 2004, Cheong et al. 2008) • Refractivity: • Radar refractivity: 4-km spatial and 5-10 min. temporal resolution

  4. Algorithm Summary Cheong et al 2008

  5. Applications of Refractivity Data • Convection Initiation • Boundary Identification and Tracking • Supercells and Tornadogenesis • Boundary Layer Moisture Characteristics Heinselman et al. 2009

  6. Convection Initiation Case: April 30, 2007

  7. Validation of Impact of Moisture Pool on Convection Initiation Scenario 1: Average surface conditions (∆Td=0ºC) Scenario 2: Average Mesonet ∆Td (∆Td=1.4ºC) Scenario 3: 10 N-unit increase observed in radar refractivity (∆Td=2ºC) NSHARP analysis: 1800 UTC 30 April 2007 LMT sounding

  8. Boundary Layer Moisture Studies Location: KFDR Time Period: 15 May - 31 July 2008 and 1 June - 31 July 2009 Objective: Investigate diurnal characteristics of boundary layer moisture field and its interseasonal and intraseasonal variability

  9. Boundary Layer Moisture Evolution 3 June 2008

  10. Boundary Layer Moisture Spatial Variability • Computed mean absolute deviation (MAD) of N and dN over different spatial scales (4-20 km) • Histograms of one-hour averaged MAD

  11. 2008 2009 W-E MAD of Refractivity • MAD is higher over larger distances • Slightly higher W-E moisture variability in 2008

  12. 2008 2009 W-E MAD of Scan-to-scan Refractivity • Almost no change in MAD with distance • Increasing MAD between 14 and 19 UTC • Slightly decreasing MAD after 19 UTC

  13. Moisture Field Movement and Spectral Analysis • Wave-like features were often observed in the moisture field between 2000 and 0000 UTC • What is the typical movement and wavelength of these features? • 2D cross-correlation analysis: velocity • 2D Fourier analysis: wavelength

  14. Refractivity-derived surface winds? • Precipitation free period • Good agreement with boundary layer and surface wind • Possible near-surface wind retrieval using refractivity?

  15. Scan-to-Scan Refractivity Refractivity Spectral analysis of moisture • Study-long two-dimensional FFT • Refractivity: moisture field dominated by W-E moisture gradient • Scan-to-scan: peak wavelength between 10-15 km

  16. Summary of Boundary Layer Applications • Statistical analysis of diurnal moisture changes showed: • Variability of moisture showed no diurnal trend and short-term moisture changes generally increased as the CBL developed • Maximum variability in the afternoon • Coherent BL structures can be tracked in scan-to-scan refractivity Contact Info: David Bodine bodine@ou.edu

  17. Moisture Field Movement Wind Speed Wind Direction

More Related