1. Characterizing urban boundary layer dynamics using
radar, lidar, sodar, surface observations and
predictions from numerical models
Mark Arend
Optical Remote Sensing Lab
City College of New York
NOAA CREST
with
E. Gutierrez *, B. Madhavan, C. M. Gan, S. Abdelazim, B. Gross,
D. Santoro, F. Moshary, J. Gonzalez *, and S. Ahmed
Collaborators:
R. D. Bornstein**, A. Martilli***,
*Mechanical Engineering Department, City College of New York
**Meteorology Department, San Jose State University
*** Research Centre for Energy, Environment and Technology (CIEMAT), Spain.
This research was supported, in part, by grants from NOAA
Through the NOAA Coperative Science Centers
NOAA ISET and NOAA CREST
and computer time from the
City University of New York High Performance Computing Center under
NSF Grants CNS and CNS

2. GOAL APPROACH Observe and model the growth of the convective
boundary layer during “bad air days”
e.g. boundary layer mixing is dominated by
thermal fluxes from the surface as opposed to
synoptic scale disturbances (fronts producing wind shears)
APPROACH
Operate ground based surface and unique remote sensing meteorological instrumentation for New York City
(our test bed for an Urban/Coastal megacity). Ingest data in a continuous and automated fashion
Pick selected meteorological events
Characterize vertical wind, temperature and mixing layer height
Develop regional high resolution Urban/Coastal mesoscale model, compare to observations and other models

3. NYCMetNet Vertical Profiling Assets and Surface Station Ingest

4. Available from NYC MetNet Web site

5. Available from NYC MetNet Web site

6. Synoptic scale condition :Warm summer days 2010
Focus on Aug 30,31 and Sept1
(from NCEP Daily Weather maps 07:00 EST)
Expect Geostrophic Winds from the NW initially
Aug 30
Aug 31
Sept 1
Sept 2

7. Observed RWP Wind Speed vs. Time
stacked every 80m
2 km
Scale 10 m/sec
surface

8. Observed RWP Wind Direction vs. Time
All vertical levels (degrees from N)
Modulo (-60,300)

9. Wind direction in degrees from N at 650m height
3rd day
First 2 days

10. Signature of thermal fluxes
Vertical Velocity from all sodar levels
(20 to 200 m above building tops)

11. WRF and uWRF Setup (** see poster 790 tomorrow)
Coarse WRF for input in to CMAQ
WRF-NMM - NCEP 0Z 24 –h forecast data.
12 km grid resolution
Mellor-Yamada-Janjic (MYJ) 2.5 local (TKE) PBL scheme. First level 27 m
NOAH Land Surface Module (Bulk Parameterization)
CMAQ version 4.6
Nested 12km x 12km
Eddy Vertical Diffusion “K-coefficient”
aero3 aerosol mechanism
uWRF with Multi-layer urban canopy surface layer parameterization*
A 24-h forecast was performed
(12-h spin up) for NYC Aug 30,31, Sept1.
Four two-way nested domains
grid spacing of 9, 3, 1 and km
Initial and boundary conditions
from NAM (resolution: 12 km).
Vertical resolution of 51 terrain
Following sigma levels (33 levels
in the lowest 1.5 km, first level ~10m.
PBL Parameterization: Bougeault
and Lacarrère (BouLac).
Urban classes were derived from the
National Land Cover Data (NLCD)**
(** see poster 790 tomorrow)
* Martilli A., Clappier A., and Rotach M. W., 2002:
An urban surface exchange parameterization for
mesoscale models, Boundary-Layer Meteorol.,
104, 26, 304.

12. Typically see temperature profile gradient discrepancy between MWR and coarse WRF MODEL --May affect how CMAQ interprets mixing layer height--
MWR
Significant differences in Air Temperature envelope can test Urban Heat Island Mechanisms.

13. August 30, 2010 MWR Temperature and Relative Humidity Profiles
WRF Temperature and Relative Humidity Profiles

14. MWR and WRF Temperature profiles
Difference plot and constant difference time evolution
August 30, 2010

15. Lidar Return Signal Range Corrected, 1064 nm

16. August 31, 2010 MWR Temperature and Relative Humidity Profiles
WRF Temperature and Relative Humidity Profiles

17. MWR and WRF Temperature profiles
Difference plot and constant difference time evolution
August 31, 2010

18. Lidar Return Signal Range Corrected, 1064 nm

19. September 1, 2010
MWR Temperature and Relative Humidity Profiles

20. MWR and WRF Temperature profiles
Difference plot and constant difference time evolution
September 1, 2010

21. Lidar Return Signal Range Corrected, 1064 nm

22. Wavelet transform analysis of PBL height. K. J. Davis, N
*Wavelet transform analysis of PBL height. K. J. Davis, N. Gamageb, et al., “An objective method for deriving atmospheric structure from airborne lidar observations,”
J. Atmos. Oceanic Technol. 17, 1455–1468 (2000).

25. Conclusion
Vertical profilers are used to characterize coastal/urban boundary layer dynamics and to test urban surface parameterization schemes Outcome: Improvements have been made to properly represent surface and boundary layer interactions Further investigation is needed to appropriately resolve discrepancies between observations and models