The Intermountain Precipitation Experiment

The Intermountain Precipitation Experiment (IPEX) is a field and research program designed to improve the understanding, analysis, and prediction of precipitation and precipitation processes in complex terrain. Information about the program can be found at the links to the left.

Doppler on Wheels collects winter weather data An article appeared in the February 2002 Bulletin of the American Meteorological Society that describes the IPEX research program: motivation, scientific objectives, field-phase research, outcome, preliminary results, and lessons learned.

The project is led, in part, by Dr. David Schultz of the Mesoscale Applications Group and Dr. Jeff Trapp (now at Purdue University) and involves scientists from the National Severe Storms Lab (NSSL), University of Utah , Desert Research Institute (DRI) , and staff from the National Weather Service Office in Salt Lake City , Hydrometeorological Prediction Center , and Storm Prediction Center . Students from the University of Utah and University of Oklahoma also participated. The field phase was held 31 January - 25 February 2000. The major scientific objectives of IPEX are:

to advance fundamental knowledge of orographic precipitation, with an emphasis on the narrow, steeply sloped Wasatch Mountains of northern Utah,
to improve knowledge of lake-effect precipitation of the Great Salt Lake,
to validate and improve high-resolution data-assimilation systems, mesoscale model performance, and quantitative-precipitation forecasts over complex terrain,
to validate and improve quantitative-precipitation estimates produced by WSR-88D's located at high elevation, and
to collect the first balloon-borne measurements of electric-field profiles in continental winter storms in the United States.

P-3 on the tarmac in Utah IPEX observing platforms include two NSSL mobile laboratories with Cross-chain LORAN Atmospheric Sounding Systems (CLASS), two, OU Doppler weather radars on wheels (DOW) , a NOAA P-3 research aircraft, Univ. of Utah's dual-frequency microwave radiometer, a vertically pointing Doppler radar (Radian, Corporation and the Salt River Project), and supplemental soundings from National Weather Service upper-air observing sites. These platforms enhance an existing surface observing system known as the Utah Mesonet .

Data collected allow project scientists to examine a number of questions and testable hypotheses concerning the interaction of dynamical and microphysical processes during orographic precipitation events, including factors controlling the distribution and intensity of precipitation across a narrow, steeply sloped mountain range like the Wasatch Mountains. Other project activities include validating and improving mesoscale model quantitative precipitation forecasts, human-produced forecast products, and quantitative precipitation estimates from WSR-88D radars. Data collected during IPEX has been used for validation studies of orographic precipitation by scientists at SUNY Stony Brook and Yale University.

FORMAL PUBLICATIONS

NEW Shafer, J. C., W. J. Steenburgh, J. A. W. Cox, and J. P. Monteverdi, 2005: Terrain influences on synoptic storm structure and mesoscale precipitation distribution during IPEX IOP3. Mon. Wea. Rev., in press. [PDF]
NEW Colle, B. A., J. B. Wolfe, W. J. Steenburgh, D. E. Kingsmill, J. A. W. Cox, and J. C. Shafer, 2005: High-resolution simulations and microphysical validation of an orographic precipitation event over the Wasatch Mountains during IPEX IOP3. Mon. Wea. Rev., 133, 2947-2971. [AMS] [PDF]
NEW Cox, J. A. W., W. J. Steenburgh, D. E. Kingsmill, J. C. Shafer, B. A. Colle, O. Bousquet, B. F. Smull, and H. Cai, 2005: The kinematic structure of a Wasatch Mountain winter storm during IPEX IOP3. Mon. Wea. Rev., in press. [AMS] [PDF]
Barstad, I. and R. B. Smith, 2005: Evaluation of an orographic precipitation model. J. Hydrometeor., 6, 85-99.[AMS] [PDF]
Schultz, D. M., and R. J. Trapp, 2003: Nonclassical cold-frontal structure caused by dry subcloud air in northern Utah during the Intermountain Precipitation Experiment (IPEX). Mon. Wea. Rev., 131, 2222-2246. [AMS] [PDF] [HTML] (First Annual CIMMS Outstanding Paper Award, 2005)
Rust, W. D., and R. J. Trapp, 2002: Initial balloon soundings of the electric field in winter nimbostratus clouds in the USA. Geophysical Research Letters, 29(20), 1959, doi:10.1029/2002GL015278. [PDF]
Schultz, D. M., W. J. Steenburgh, R. J. Trapp, J. Horel, D. E. Kingsmill, L. B. Dunn, W. D. Rust, L. Cheng, A. Bansemer, J. Cox, J. Daugherty, D. P. Jorgensen, J. Meitin, L. Showell, B. F Smull, K. Tarp, and M. Trainor, 2002: Understanding Utah winter storms: The Intermountain Precipitation Experiment. Bull. Amer. Meteor. Soc., 83, 189-210. [AMS] [PDF] [PDF-extended version (draft)] [HTML-extended version]

INFORMAL PUBLICATIONS

Colle, B. A., J. Wolfe, J. Steenburgh, D. Kingsmill, J. A. W. Cox, and J. Shafer, 2005: High resolution simulations and microphysical validation of an orographic precipitation event over the Wasatch Mountains during IPEX IOP3. Preprints, 21st Conference on Weather Analysis and Forecasting/17th Conference on Numerical Weather Prediction, Washington, DC, Amer. Meteor. Soc., 9.7. [AMS]
Colle, B. A., M. Garvert, J. A. W. Cox, W. J. Steenburgh, D. E. Kingsmill, J. B. Wolfe, and C. P. Woods, 2004: Some comparisons between IMPROVE-2 and IPEX kinematic and precipitation structures and bulk microphysical verification. Preprints, 11th Conference on Mountain Meteorology and the Annual Mesoscale Alpine Program (MAP), Bartlett, NH, Amer. Meteor. Soc. [AMS]
Steenburgh, W. J., J. A. W. Cox, J. C. Shafer, D. E. Kingsmill, and B. A Colle, 2003: Orographic precipitation processes over the Wasatch Mountains during IPEX IOP 3. Preprints, 10th Conf. on Mesoscale Processes, Portland, OR, Amer. Meteor. Soc. [PDF]
Ladue, J. G., 2002: The structure of a tornadic bow echo in Idaho. Preprints, 21st Conf. on Severe Local Storms, San Antonio, TX, Amer. Meteor. Soc.
Shafer, J. C., W. J. Steenburgh, and J. A. W. Cox, 2002: Analysis of an orographically modified cyclone over the western United States during IPEX IOP 3. Preprints, Tenth Conf. on Mountain Meteorology, Park City, UT, Amer. Meteor. Soc. [PDF]
Kingsmill, D. E., H. Cai, J. A. W. Cox, W. J. Steenburgh, 2002: Microphysical structure of orographic precipitation along the Wasatch Mountains during IPEX. Preprints, Tenth Conf. on Mountain Meteorology, Park City, UT, Amer. Meteor. Soc. [PDF]
Schultz, D. M., 2002: Structure and evolution of a tornadic cold front in the Intermountain West. Preprints, Tenth Conf. on Mountain Meteorology, Park City, UT, Amer. Meteor. Soc. [AMS]
Cox, J. A. W., W. J. Steenburgh, and D. E. Kingsmill, 2002: Dual-Doppler analysis of the kinematic structure of a Wasatch mountain winter storm. Preprints, Tenth Conf. on Mountain Meteorology, Park City, UT, Amer. Meteor. Soc. [PDF]
Cox, J. A. W., W. J. Steenburgh, D. E. Kingsmill, and B. A. Colle, 2001: Orographic precipitation processes associated with the Wasatch Mountains during IPEX IOP3. Preprints, Ninth Conf. on Mesoscale Processes, Fort Lauderdale, FL, Amer. Meteor. Soc., 196-197. [PDF]
Schultz, D. M., W. J. Steenburgh, R. J. Trapp, D. Kingsmill, L. Dunn, 2000: Preliminary Results from the Intermountain Precipitation Experiment. Preprints, Ninth Conf. on Mountain Meteorology, Aspen, CO, 316-317. [HTML]
Ciliberti, C. M., J. D. Horel, and S. M. Lazarus, 2000: Sensitivity Experiments With a High Resolution Data Assimilation Scheme. Preprints, Ninth Conf. on Mountain Meteorology, Aspen, CO, 413-416. [PDF]

THESES

Shafer, J. C., 2002: Synoptic and Mesoscale Analysis of Wasatch Mountain Snow Storm. M.S. thesis, Department of Meteorology, University of Utah, 70 pp. [PDF]
Cox, J. A. W., 2002: Kinematic structure of a Wasatch Mountain snowstorm. M.S. thesis, Department of Meteorology, University of Utah, 60 pp. [PDF]
Cheng, L., 2001: Validation of Quantitative Precipitation Forecasts During the Intermountain Precipitation Experiment. M.S. thesis, Department of Meteorology, University of Utah, 137 pp. [HTML]

ONLINE PRESENTATIONS

Intermountain Weather Workshop: 7 November 2002