Topoclimatic variations in temperature and winds as the basis for mountain refugia. C. David Whiteman University of Utah Salt Lake City

Transcription

1 Topoclimatic variations in temperature and winds as the basis for mountain refugia C. David Whiteman University of Utah Salt Lake City MtnClim 2014, Midway, UT, Sept 2014

2 Definitions temperature inversion an atmospheric layer in which temperature increases with height lapse rate (LR) rate at which temperature T decreases with height ( dt/dz) environmental LR the actual atmospheric lapse rate (determined from a temperature sounding T(z)) dry adiabatic LR thermodynamic rate of T decrease when parcel is lifted adiabatically (Γ = -dt/dz = 9.8 C/km) potential temperature the temperature Θ a parcel of air would have if brought to 1000 mb (~sea level) stable layer an atmospheric layer with a lapse rate less than 9.8 C/km cold air pool a terrain-confined atmospheric stable layer The heat deficit to 2000 m MSL is proportional to the area between the environmental soundings and the dashed lines Θ

3 Local rate of change of potential temperature Local rate of change of potential temperature gradient Stability increases when

4 AWS Radiosonde RASS ICs HOBO T datalogger/ radiation shield Tethered balloon

5 The Salt Lake Basin, Utah Salt Lake basin

6 Three types of SLC cold-air pools Jan 2004 Craig Clements photo 20 Jan 2005 Jim Steenburgh photo Erik Crosman photo Photo Credit: Tom Smart, Deseret Morning News

7 Relationships between twice-daily heat deficits H 22 and daily PM 10 and PM 2.5 concentrations. The dashed line marks a threshold heat deficit of 4.04 MJ m -2. PM 2.5 and PM 10 concentrations are normalized so that the dashed horizontal line also indicates the NAAQS for these variables, 35 and 150 mg m -3, respectively. Whiteman et al. (2014)

8 Potential temperatures from 12-hourly radiosonde ascents at Salt Lake City for 2200 m MSL (solid line) and the surface (dashed line). The shading between the upper and lower curves is a measure of atmospheric stability in the valley. Whiteman et al. (2014)

9 Lareau et al. (2013)

10 Lareau et al. (2013)

11 Lareau et al. (2013)

12 Lareau et al. (2013)

13 Lareau et al. (2013)

14 Lareau et al. (2013)

15 Lareau et al. (2013)

16 The mean wintertime heat deficit (1 Oct - 31 Mar) bounces around from year to year depending on the frequency, duration and strength of passing high pressure weather disturbances Whiteman et al. (2014)

17 29 Dec Jan 2001 SLC cold-air pool Animation slide 1

18 Seiches - T oscillations Columbia Basin cold pool Whiteman et al. (2001) Negative convection, Grand Canyon: Whiteman et al. (1999)

19 Pseudo-vertical soundings & superadiabatic profiles composite: 16,17,18,19,24,25 Jan 2014 Salt Lake Valley 1. Consistent exposure of temperature sensors, radiation shielding 2. Urban Heat Island (UHI) 3. Cold air intrusions into depressions UHI Meteor Crater, AZ Whiteman et al. (2010)

20 Gruenloch Sinkhole - Eastern Alps Steinacker et al. (2007)

21 Temperature time series - Gruenloch Dec 1 Dec 4 Dorninger et al. (2011)

22 Classification of cold pool events Dorninger et al. (2011)

23 Basin Meteorology Whiteman (1990) Extreme minimum temperatures usually occur in mountain basins, rather than in valleys: Peter Sink, UT F (-56.3 C) Feb 1, 1985 West Yellowstone, MT -66 F (-54 C) Feb 1933 Taylor Park, CO -60 F (-51 C) Feb 1951 Fraser, CO -53 F (-47 C) Jan 1962 Stanley, ID -54 F (-48 C) Dec 1983 Gruenloch Basin, Austria -63 F (-52.6 C) between 19 Feb and 4 Mar 1932

24 Cold air pools in valleys Trappers/drainers: Whiteman et al. (1996) Whiteman (2000)

25 Skyview fraction, dewfall, cooling rates Multi-sinkholes: Whiteman et al. (2004) 3-D radiative transfer: Hoch et al. (2011) Cooling rates: DeWekker & Whiteman (2006) Dewfall: Whiteman et al. (2007) Kennecott s Bingham Copper Mine, Utah

26 Diurnal Mountain Winds Whiteman (2000) Review of diurnal mountain wind systems: Zardi and Whiteman (2012) Cross-valley flows: Lehner et al. (2010); Lehner and Whiteman (2012, 2014)

27 Slope flows Whiteman (2000) Slope winds are gravity or buoyancy circulations following the dip of the underlying slope and caused by differences in temperature between air heated or cooled over the mountain slopes and air at the same altitude over the valley center.

28 Downslope flows Animation slide 2 Gruenloch Basin sidewall 2051 UTC 2 June 2002 From R. Steinacker

29 Whiteman (2000) Early in the evening when the atmosphere is near-neutral, downslope flows are strong and they converge on the valley floor. As the ambient stability (valley inversion) builds later in the evening, the downslope flows cannot penetrate readily to the valley floor and converge at higher altitudes.

30 Meteor Crater, Arizona Near-circular basin Surrounded by a uniform plain sloping upwards to the SW with 2% slope Uniform rim height - no major saddles or passes m 170 m N John S. Shelton

31 Propagation of shadows and insolation patterns Animation slide 3 Meteor Crater, Arizona Whiteman & Kahler (2006)

32 Meteor Crater, MST 20 OCT 2013 Animation slide 4

33 Meteor Crater, MST 20 OCT 2013 Animation slide 5

34 The End Torres del Paine Sigrid & Ron Smith

35 References Dorninger, M., C. D. Whiteman, B. Bica, S. Eisenbach, B. Pospichal, and R. Steinacker, 2011: Meteorological events affecting cold-air pools in a small basin. J. Appl. Meteor. Climatol, 50, Hoch, S. W., C. D. Whiteman, and B. Mayer, 2011: A systematic study of longwave radiative heating and cooling within valleys and basins using a three-dimensional radiative transfer model. J. Appl. Meteor. Climatol., 50, Lareau, N., E. Crosman, C. D. Whiteman, J. D. Horel, S. W. Hoch, W. O. J. Brown, and T. W. Horst, 2013: The Persistent Cold-Air Pool Study. Bull. Amer. Meteor Soc., 94, Lehner, M., and C. D. Whiteman, 2012: The thermally driven cross-basin circulation in idealized basins under varying wind conditions. J. Appl. Meteor. Climatol., 51, Lehner, M., and C. D. Whiteman, 2014: Physical mechanisms of the thermally driven cross-basin circulation. Quart. J. Roy. Meteor. Soc., 140, Lehner, M., C. D. Whiteman, and S. W. Hoch, 2011: Diurnal cycle of thermally driven cross-basin winds in Arizona's Meteor Crater. J. Appl. Meteor. Climatol., 50, Steinacker, R., C. D. Whiteman, M. Dorninger, B. Pospichal, S. Eisenbach, A. M. Holzer, P. Weihs, E. Mursch-Radlgruber, and K. Baumann, 2007: A sinkhole field experiment in the eastern Alps. Bull. Amer. Meteor. Soc., 88, De Wekker, S. F. J., and C. D. Whiteman, 2006: On the time scale of nocturnal boundary layer cooling in valleys and basins and over plains. J. Appl. Meteor., 45, Whiteman, C. D., 1990: Observations of Thermally Developed Wind Systems in Mountainous Terrain. Chapter 2 in Atmospheric Processes Over Complex Terrain, (W. Blumen, Ed.), Meteorological Monographs, 23, no. 45. American Meteorological Society, Boston, Massachusetts, Whiteman, C. D., 2000: Mountain Meteorology: Fundamentals and Applications. Oxford University Press, New York, 355pp. Whiteman, C. D., S. W. Hoch, J. D. Horel, and A. Charland, 2014: Relationship between particulate air pollution and meteorological variables in Utah's Salt Lake Valley. Atmos. Environ., 94, Whiteman, C. D., S. W. Hoch, M. Lehner, and T. Haiden, 2010: Nocturnal cold air intrusions into Arizona's Meteor Crater: Observational evidence and conceptual model. J. Appl. Meteor. Climatol., 49, Whiteman, C. D., S. F. J. De Wekker, and T. Haiden, 2007: Effect of dewfall and frostfall on nighttime cooling in a small, closed basin. J. Appl. Meteor., 46, Whiteman, C. D., T. Haiden, B. Pospichal, S. Eisenbach, and R. Steinacker, 2004: Minimum temperatures, diurnal temperature ranges and temperature inversions in limestone sinkholes of different size and shape. J. Appl. Meteor., 43, Whiteman, C. D., S. Zhong, W. J. Shaw, J. M. Hubbe, X. Bian, and J. Mittelstadt, 2001: Cold pools in the Columbia Basin. Weather and Forecasting, 16, Whiteman, C. D., S. Zhong, and X. Bian, 1999: Wintertime boundary-layer structure in the Grand Canyon. J. Appl. Meteor., 38, Whiteman, C. D., T. B. McKee, and J. C. Doran, 1996: Boundary layer evolution within a canyonland basin. Part I. Mass, heat, and moisture budgets from observations. J. Appl. Meteor., 35, Zardi, D., and C. D. Whiteman, 2012: Diurnal Mountain Wind Systems. Chapter 2 in: Mountain Weather Research and Forecasting (Chow, F. K., S. F. J. DeWekker, and B. Snyder (Eds.)). Springer, Berlin, pp