Stanley Trier

Project Scientist
TIIMES - MMM
WCAS

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: FL3 - 2019
Telephone: 303-497-8912
Email: trier@ucar.edu
Home Page

Project Summary:

Click on picture to view the entire figure.

TOP PANEL: ARW-WRF model terrain for simulation of diurnal cycle of precipitation. Insets denote subdomains for

LOWER PANEL: 7-day area-averaged rain rates.

Advanced Research Weather Forecast Model
(ARW-WRF)

During the past year I have participated in TIIMES research that has been co-sponsored by the NCAR Water Cycle across Scales Initiative. The work has focused on both land surface effects on the diurnal cycle of the planetary boundary layer and precipitation, and the role of the Rocky Mountain Cordillera on the diurnal cycle of propagating deep convection across the continental United States.

I have performed process studies of these effects using the Advanced Research Weather Forecast Model (ARW-WRF) at convection resolving resolutions for both retrospective periods and for more climatologically based environmental conditions. Twelve-day simulations during the International H2O Project (IHOP) coincided with a persistent soil moisture anomaly with drier than normal soil over the high plains (W of -98° LON) with wetter than normal soil moisture over parts of the Midwest. These simulations indicated the importance of initial land surface conditions and land-surface model physics in determining the afternoon PBL response and subsequent evening precipitation over these areas (Trier et al. 2007).  Simulations of the diurnal cycle of warm-season convective precipitation in the lee of the Rocky Mountains based on monthly-averaged initial conditions (July 2001) captured a diurnally reversing mountain-plains vertical circulation that modulates the diurnal cycle of precipitation. Here, subsidence is present along and in the lee of the Rockies immediately following sunrise. A mid-late morning shallow vertical motion couplet, with weak ascent over the mountains and subsidence in the lee, strengthens and deepens in response to mountain convection by early afternoon. The deep subsidence over the high plains restricts local development of precipitation until late afternoon and early evening, which becomes more intense as it moves into the central Plains overnight (Figure 1, lower panel) consistent with previous observations.

Upcoming work will continue on understanding the interplay between the mountains and downstream continental precipitation. I also plan to participate in new work that studies land-surface/atmospheric coupling effects related to different vegetation states.

Reference:

Trier, S. B., F. Chen, K. W. Manning, M. A. LeMone, and C. A. Davis, 2007: PBL and precipitation differences in simulations of a 12-day warm-season convection period using different land surface models and soil wetness. Mon. Wea. Rev., submitted.

Community Service:

• Associate Editor - Monthly Weather Review
• Member - Severe Local Storms (SLS), American Meteorological Society (AMS)
• Member - SLS Conference Program, American Meteorological Society (AMS)

Presentations:

• Influences of land-surface atmosphere interactions on precipitation during 9-21 June IHOP, San Antonio USA, January 2007
• Mesoscale convective vortices (MCVs) observed during the Bow-echo and MCV Experiment (BAMEX) 2003, Boulder USA, November 2006
• Mesoscale convective vortices (MCVs) observed during the Bow-echo and MCV Experiment (BAMEX) 2003, St. Louis USA, November 2006
• Mesoscale convective vortices (MCVs) observed during the Bow-echo and MCV Experiment (BAMEX) 2003, Norman USA, April 2007
• WRF simulations of the initiation of long-lived precipitation sequences in the lee of the Rockies, Waterville Valley USA, August 2007

Publications:

Trier, S. B., F. Chen, K. W. Manning, M. A. Lemone, C. A. Davis, 2007: Sensitivity of the PBL and precipitation in 12-day simulations of warm-season convection using different land surface models and soil wetness conditions. Mon. Wea. Rev.. (accepted)

Trier, S. B., C. A. Davis, 2007: Mesoscale convective vortices observed during BAMEX. Part II: Influences on secondary deep convection. Mon. Wea. Rev., 135, 2051-2075, doi: 10.1175/MWR3399.1.

Davis, C. A., S. B. Trier, 2007: Mesoscale convective vortices observed during BAMEX. Part I: Kinematic and thermodynamic structure. Mon. Wea. Rev., 135, 2029-2049, doi: 10.1175/MWR3398.1.

Chen, F., K. W. Manning, M. A. LeMone, S. B. Trier, J. G. Alfieri, R. Roberts, M. Tewari, D. Niyogi, T. W. Horst, S. P. Oncley, J. B. Basara, P. D. Blanken, 2007: Description and evaluation of the characteristics of the NCAR high-resolution land data assimilation system. J. Appl. Meteor. Climat., 46, 694-713, doi: 10.1175/JAM2463.1.

Trier, S. B., F. Chen, K. W. Manning, 2007: Influences of land-atmosphere interactions on precipitation during 9-21 June IHOP-2002. 21st Conf. on Hydrology, San Antonio, TX, US.

Ahijevych, D., G. Bryan, M. Weisman, S. Trier, C. Davis, D. Dowell, 2006: Composite bow echo observed during BAMEX. 23rd Conf. on Severe Local Storms, St. Louis, MO, US.