Dr. John Nielsen-Gammon

Research Interests

Dr. Nielsen-Gammon's research group uses a combination of observational and numerical techniques to study the characteristics, dynamics, and forecastability of particular weather phenomona. For large-scale phenomena, Nielsen-Gammon has pioneered the application of various techniques involving potential vorticity and nonlinear balance. Recent studies include factors governing the development and intensification of upper-tropospheric mobile troughs and the role of certain aspects of upper-tropospheric mobile trough configuration on the severe weather environment in the Great Plains.

Much of Dr. Nielsen-Gammon's recent work has involved air pollution meteorology. He has employed sophisticated techniques, such as Ensemble Kalman Filter data assimilation, to produce high-resolution simulations of the Houston/Galveston area for the purposes of photochemical modeling and policy development. He has developed conceptual models of ozone formation in the Houston area and is working on the integration of a variety of observational information to determine the spatial extent and magnitude of the Houston urban heat island.

As Texas State Climatologist, Dr. Nielsen-Gammon has supervised research on mechanisms for summertime drought, estimation of long-term trends from climatological data sets, the development of high-resolution drought information, and the climatology of regional air pollution.

Selected Publications

• Nielsen-Gammon, J. W., and D. A. Gold, 2008: Dynamical diagnosis: a comparison of quasigeostrophy and Ertel potential vorticity. Sanders Memorial Volume, in press.
• Gold, D. A., and J. W. Nielsen-Gammon, 2008: Potential vorticity diagnosis of the severe convective regime. Part IV: Comparison with numerical simulations of the 1999 Oklahoma outbreak. Mon. Wea. Rev., 136, 1612-1629.
• Gold, D. A., and J. W. Nielsen-Gammon, 2008: Potential vorticity diagnosis of the severe convective regime. Part III: The Hesston tornado outbreak. Mon. Wea. Rev., 136, 1593-1611.
• Nielsen-Gammon, J. W., and D. A. Gold, 2008: Potential vorticity diagnosis of the severe convective regime. Part II: The impact of idealized anomalies. Mon. Wea. Rev., 136, 1582-1592.
• Gold, D. A., and J. W. Nielsen-Gammon, 2008: Potential vorticity diagnosis of the severe convective regime. Part I: Methodology. Mon. Wea. Rev., 136, 1565-1581.
• Nielsen-Gammon, J. W., C. L. Powell, M. J. Mahoney, W. Angevine, C. Senff, A. White, C. Berkowitz, C. Doran, and K. Knupp, 2007: Multi-sensor estimation of mixing heights over a coastal city. J. Appl. Meteor. Clim., 47, 27-43.
• Nielsen-Gammon, J. W., and *D. A. Gold, 2008: Potential vorticity diagnosis in the quasigeostrophic and nonlinear balance systems. J. Atmos. Sci., 65, 172-188.
• Nielsen-Gammon, J. W., 2007: An Inconvenient Truth: The scientific argument. GeoJournal, 70, 21-26, doi:10.1007/s10708-008-9126-z.
• Pielke Sr., R., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, J. Angel, R. Mahmood, S. Foster, R. T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multidecadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.
• Pielke Sr., R., J. Nielsen-Gammon, C. Davey, J. Angel, O. Bliss, N. Doesken, M. Cai, S. Fall, D. Niyogi, K. Gallo, R. Hale, K. G. Hubbard, X. Lin, H. Li, and S. Raman, 2007: Documentation of uncertainties and bias associated with surface temperature measurement sites for climate change assessment. Bull. Amer. Meteor. Soc., 88, 913-928.
• Nielsen-Gammon, J. W., R. T. McNider, W. M. Angevine, A. B. White, and K. Knupp, 2007: Mesoscale model performance with assimilation of wind profiler data: Sensitivity to assimilation parameters and network configuration. J. Geophys. Res., 112, D09119, doi:10.1029/2006JD007633.
• Stuart, A. L., A. Aksoy, F. Zhang, and J. W. Nielsen-Gammon, 2007: Ensemble-based data assimilation and targeted observation of a chemical tracer in a sea breeze model. Atmos. Env., 41, 3082-3094.
• Zhang, F., N. Bei, J. W. Nielsen-Gammon, G. Li, R. Zhang, A. Stuart, and A. Aksoy, 2007: Impacts of meteorological uncertainties on ozone pollution predictability estimated through meteorological and photochemical ensemble forecasts. J. Geophys. Res., 112, D04304, doi:10.1029/2006JD007429.
• Aksoy, A., F. Zhang, and J. W. Nielsen-Gammon, 2006: Ensemble-based simultaneous state and parameter estimation in a two-dimensional sea breeze model. Mon. Wea. Rev.,, 134, 2951-2970.
• Aksoy, A., F. Zhang, and J. W. Nielsen-Gammon, 2006: Ensemble-based simultaneous state and parameter estimation with MM5. Geophys. Res. Let., 33, L12801, doi:10.1029/2006GL026186.
• Sippel, J. A., J. W. Nielsen-Gammon, and S. E. Allen, 2006: The multiple vortex nature of tropical cyclogenesis. Mon. Wea. Rev.,, 134, 1796-1814.
• Zhang, F., A. Odins, and J. W. Nielsen-Gammon, 2006: Mesoscale predictability of an extreme warm-season precipitation event. Wea. Forecasting, 21, 149-166.
• Nielsen-Gammon, J. W., F. Zhang, A. M. Odins, and B. Myoung, 2005: Extreme rainfall in Texas: Patterns and predictability. Phys. Geog., 26,340-364
• Fan, J., R. Zhang, G. Li, J. Nielsen-Gammon, and Z. Li, 2005: Simulations of fine particulate matter (PM2.5) in Houston, Texas. J. Geophys. Res., 110, D16203, doi:10.1029/2005JD005805.
• Aksoy, A., F. Zhang, J. W. Nielsen-Gammon, and C. C. Epifanio, 2005: Ensemble-based data assimilation for thermally forced circulations. J. Geophys. Res., 110, D16105, doi:10.1029/2004JD005718.
• Banta, R. M., C. J. Senff, J. W. Nielsen-Gammon, T. B. Ryerson, L. S. Darby, R. J. Alvarez, S. P. Sandberg, E. J. Williams, and M. Trainer, 2005: A bad air day in Houston. Bull. Amer. Meteor. Soc., 86, 657-669.
• Orville, R. E., G. R. Huffines, J. Nielsen-Gammon, R. Zhang, B. Ely, S. Steiger, S. Phillips, S. Allen, and W. Read, 2001: Enhancement of cloud-to-ground lightning over Houston, Texas. Geophys. Res. Lett., 28, 2597-2600.
• Nielsen-Gammon, J. W., 2001: A visualization of the global dynamic tropopause.   Bull. Amer. Meteor. Soc., 82, 1151-1168.
• Wandishin, M. S., J. W. Nielsen-Gammon, and D. Keyser, 2000: A potential vorticity diagnostic approach to upper-level frontogenesis within a developing baroclinic wave. J. Atmos. Sci., 57, 3918-3938.
• Nielsen-Gammon, J. W., and D. Keyser, 2000: Effective stratification for pseudoadiabatic ascent. Mon. Wea. Rev., 128, 3007-3010.
• Igau, R. C., and J. W. Nielsen-Gammon, 1998: Low-level jet development during a numerically simulated return flow event. Mon. Wea. Rev., 126, 2972-2990.
• Morgan, M. C., and J. W. Nielsen-Gammon, 1998: Using tropopause maps to diagnose midlatitude weather systems. Mon. Wea. Rev., 126, 2555-2579.
• Nielsen-Gammon, J. W., M. I. Biggerstaff, M. E. Alcorn, D. Austin, K. P. Bowman, D. Djuric, J. Guynes, R. L. Panetta, R. White, and L. J. Wicker, 1996: Texas A&M University's Laboratory for the Exploration of Atmospheric Processes - TAMU's LEAP. Bull. Amer. Meteor. Soc., 77, 2907-2918.
• Nielsen-Gammon, J. W., and R. J. Lefevre, 1996: Piecewise tendency diagnosis of dynamical processes governing the development of an upper-tropospheric mobile trough. J. Atmos. Sci., 53, 3120-3142.
• Livingston, E. S., J. W. Nielsen-Gammon, and R. E. Orville, 1996: A climatology, synoptic assessment, and thermodynamic evaluation for cloud-to-ground lightning in Georgia: A study for the 1996 Summer Olympics. Bull. Amer. Meteor. Soc., 77, 1483-1495.
• Nielsen-Gammon, J. W., 1995: Dynamic conceptual models of upper-level mobile trough formation: comparison and application. Tellus, 47A, 705-721.
• Lefevre, R. J., and J. W. Nielsen-Gammon, 1995: An objective climatology of mobile troughs in the Northern Hemisphere. Tellus, 47A, 638-655.
• Nielsen-Gammon, J. W., and W. Read, 1995: Detection and interpretation of left-moving severe thunderstorms using the WSR-88D: A case study. Wea. Forecasting, 10, 127-140.
• Bosart, L. F., and J. W. Nielsen, 1993: Radiosonde penetration of an undilute cumulonimbus anvil. Mon. Wea. Rev., 121, 1688-1702.
• Nielsen, J. W., and R. M. Dole, 1992: A survey of extratropical cyclone characteristics during GALE. Mon. Wea. Rev., 120, 1156-1167.
• Nielsen, J. W., 1992: In situ observations of Kelvin-Helmholtz waves along a frontal inversion. J. Atmos. Sci., 49, 369-386.
• Nielsen, J. W., and P. P. Neilley, 1990: The vertical structure of New England coastal fronts Mon. Wea. Rev., 118 1793-1807.
• Nielsen, J.W., 1989: The formation of New England coastal fronts. Mon. Wea. Rev., 117, 1380-1401.