1 / 47

Evening and nocturnal winds in the Hudson valley

Evening and nocturnal winds in the Hudson valley David R. Fitzjarrald 1 , Jeffrey M. Freedman 2 , Ricardo K. Sakai 1 , Mathew J. Czikowsky 1 , and Jessica Neiles 3 1. Atmospheric Sciences Research Center, UAlbany, SUNY 2. Atmospheric Information Services, Albany, NY 3. NWSFO Wilmington NC.

brosh
Download Presentation

Evening and nocturnal winds in the Hudson valley

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. Evening and nocturnal winds in the Hudson valley David R. Fitzjarrald1, Jeffrey M. Freedman2, Ricardo K. Sakai1, Mathew J. Czikowsky1, and Jessica Neiles3 1. Atmospheric Sciences Research Center, UAlbany, SUNY 2. Atmospheric Information Services, Albany, NY 3. NWSFO Wilmington NC

  2. • a look at the decaying CBL in the Hudson valley • partial nocturnal disconnection of surface and SBL • detect presence of a little nocturnal jet. { All above illustrated with examples from HVAMS, Hudson Valley Ambient Meterorology Study }

  3. The Hudson Valley Catskills ALB Hudson Valley Kingston POU HPN NYC

  4. Old news--stations in the FOG-82 program Albany NY - 26 Stations at the Albany region: moderately complex terrain and the presence of obstacles (trees and buildings) (Acevedo & Fitzjarrald, 2001, 2003)

  5. The early evening transition (EET) marks the transition from horizontal homogeneity to heterogeneity in the surface layer. Spatial variability: at any minute, the standard deviation of the values at 26 stations Temporal variability: at one station, the standard deviation of groups of 30 minutes

  6. Fitzjarrald and Lala, 1989 “Hudson Valley fog environments”, JAM 28,1303-1328.

  7. Cartoon version (Stull, 1988) Model version, Zeman, 1979

  8. Alaska (60°N) Surface hodograph rotation Namibia (19° S) * NB: all that rotates is not due to the Coriolis effect…… Amazon (3°S)

  9. The simple-minded approach, temporal spiral toward The geostrophic point

  10. HVAMS intensive field obs, 10-11/2003 ISSF Typical LES domain

  11. PAM ISSF station at Green Acres Airport

  12. North Zena Cornfield (Station 7) West East South

  13. PAM Station Network Windroses and Transmission Factors

  14. 0600 - 1800 LT

  15. 1800 - 0600 LT

  16. ISSF: 9-station 5-minute surface u* averages max

  17. ISSF: 9-station 5-minute surface <w’T’> averages max zero

  18. 10/6/03 10/8/03 10/13/03 10/18/03 10/30/03 10/24/03

  19. Flights made at specified fractions of the mixed layer height…… Sensible heat flux dies, killing mixing…

  20. Net radiative flux <w’T’> Sensible heat flux Q* Potential temperature departure Q - Qo

  21. CO2 flux concentration Left to do--what kind of CO2 advection/entrainment combo. can cause this?

  22. sw/w*2 Key result, mixing in vertical dies at sunset, but horizontal wind variation persists into the night…. [t* -t*(Hmax) ] -1.2

  23. What do surface stations ‘see’ at night in the complicated landscape of the Hudson valley?

  24. Some problems with how models deal with nocturnal conditions…… Are we in the mathematically ambiguous zone? Pulsed mixing, but with a caveat… McNider et al., 1995, MM5 results… Van de Wiel et al., 2002

  25. VERTICAL STRUCTURE Black: maximum surface T or q blue: T or q at station 1 squares: T or q at 30 m (soundings) triangles: T or q at surface (soundings) (Acevedo & Fitzjarrald, 2001, 2003) The value at 30 m from the soundings is in excellent agreement to the maximum surface values observed in the network. Mixing can bring a sheltered point to a regionally characteristic value.

  26. When turbulence restarts at a station, its surface temperature goes up to the value observed at the higher, windier stations. Acevedo & Fitzjarrald, 2001, 2003 The maximum surface value can be used as an approximation to the temperature at the height to which the surface connects during turbulence breakdowns

  27. HVAMS reveals similar signal, but over a wider region…

  28. Along-valley wind maximum observed intermittently at the sfc on the east side of the river at higher Sites--leads one to seek the Hypothesized jet-like structure at Low (50-100 m) along the valley.

  29. Shallow along-valley jet-like circulations appear at night in the Hudson Valley…. Tethered balloon results from 1982 obs at Albany airport…. q qsat U V Along-valley wind Fitzjarrald and Lala, 1989

  30. Jet-like feature seen during HVAMS in the early morning..

  31. ‘close approaches’ to 5 small airfields …… Surface station elevations

  32. Aircraft altitude V U Missed approach to Green Acres Airport, Oct. 17, 2003, 1300 UT (0900 LST)

  33. October 30, 2003 case..

  34. 10/30/03 Close approaches Cross valley Along valley

  35. Not a classic SBL, but also there is an ‘accumulation’ layer that depends on local effects.

  36. another case study: Oct 17, 2003 1200 Z surface map Shallow along-valley flow… q Q

  37. The effect of the density interface at the top of the SBL made visible by a cement plant plume (west side of river), October 17, 2003. Photo by King Air pilot Thomas Drew.

  38. Profiles made from close approaches, 10/17/2003 1242-1307 UT V U Q CO2

  39. V U q Q CO2 O3

  40. No low-level NS wind maximum detected by the NOAA profiler at Schenectady airport “L”

  41. 10/17/03 Kingston/Ulster Airport: MIPS 915 Profiler km Echo intensity 915 km 12Z 0Z 0Z MIPS Sodar Echo intensity m km Surface data: T, Tdew Wind speed 360 Wind direction 0 MIPS Surface Hard to see the low level jet feature in profiler observations at Kingston-Ulster airport. Southerly component not observed by profiler

  42. Time series from TAOS 10/16/03 18-23 LST Easterly flow in the early evening

  43. Southerly flow appears only in the early morning hours. ASRC sodar at Schodack Island State Park

  44. So we’ve not got it all sorted out yet. Still have to do: • find the pressure gradients that drive the nocturnal jet. • seek the wind rotation in the decaying CBL in the profiler & sodar records. • quantify how landscape and topographic structure are connected to microclimate and mixing frequency at sfc stations. • figure out how there can be an SBL at all if sfc stations all decouple! (decide where the mixing ‘hot spots’ are in a landscape.)

  45. What to do about forecasting the Hudson very low level jet: • detailed modeling maybe not yet possible (high resolution needed over large region.) • ‘modeling’ through grotesque parameterization (always briefly satisfying, but…) • continued study of profilers, seek ‘ideal’ spots for ongoing simple observations (sodar, tall towers, profilers).

  46. HVAMS is supported by NSF grant ATM0313718. Jeff Freedman, Matt Czikowsky, Ricardo Sakai, and Alex Tsoyref, the HVAMS team.. Special thanks to Jessica Neiles, Project assistant during the intensive field phase. Undergraduate students Kim Sutkevich, Jason Herb, and Aaron Feinberg assisted both during the field operations and in subsequent data analysis when they were joined by Matt Doody. We thank the teams from U. Wyoming, (especially Larry Oolman, pilot Tom Drew) NCAR ATD (Steve Oncley, Kurt Knudson, Tony Delany and many others), and U. Alabama HuntsvilleMIPS team for their help.

More Related