scholarly journals Pseudovertical Temperature Profiles in a Broad Valley from Lines of Temperature Sensors on Sidewalls

2014 ◽  
Vol 53 (11) ◽  
pp. 2430-2437 ◽  
Author(s):  
C. David Whiteman ◽  
Sebastian W. Hoch
Keyword(s):  
Salt Lake ◽  
Low Cost ◽  
Temperature Inversion ◽  
Temperature Sensors ◽  
Lapse Rate ◽  
Future Research ◽  
Temperature Structure ◽  
Salt Lake Valley ◽  
The North ◽  
Free Air

AbstractPseudovertical temperature “soundings” from lines of inexpensive temperature sensors on the sidewalls of Utah’s Salt Lake valley are compared with contemporaneous radiosonde soundings from the north, open end of the valley. Morning [0415 mountain standard time (MST)] soundings are colder, and afternoon (1615 MST) soundings are warmer than radiosonde soundings because of warm and cold boundary layers that form over the slopes. Cross-valley temperature differences occur between east- and west-facing sidewalls because of differing insolation. Differences in vertically averaged pseudovertical and radiosonde temperatures are generally within 1°C, with a standard deviation of 2°–3°C. The pseudovertical soundings are especially good proxies for radiosondes in winter. The sounding comparisons identified along-valley differences in temperature, inversion depth, and lapse rate that have led to hypotheses concerning their causes, to be evaluated with future research. The low cost and much better time resolution of the pseudovertical soundings suggest that such lines will be a useful supplement to valley radiosondes and will have significant operational advantages if available in real time. Lines of surface-based sensors will prove useful in identifying intravalley meteorological differences and may be used to estimate free-air temperature structure in other valleys where radiosondes are unavailable.

scholarly journals Optimal Ranking Regime analysis of TreeFlow dendrohydrological reconstructions

2015 ◽  
Vol 11 (2) ◽  
pp. 755-803
Author(s):  
S. A. Mauget
Keyword(s):  
San Francisco ◽  
North Atlantic ◽  
18Th Century ◽  
Southern Oscillation ◽  
Salt Lake ◽  
Time Windows ◽  
Future Research ◽  
The North ◽  
Climate Reconstructions ◽  
Optimal Ranking

Abstract. The Optimal Ranking Regime (ORR) method was used to identify 6–100 year time windows containing significant ranking sequences in 55 western US streamflow reconstructions, and reconstructions of the level of the Great Salt Lake and San Francisco Bay salinity during 1500–2007. The method's ability to identify optimally significant and non-overlapping runs of low and high rankings allows it to re-express a reconstruction time series as a simplified sequence of regime segments marking intra- to multi-decadal (IMD) periods of low or high streamflow, lake level, or salinity. Those ORR sequences, referred to here as Z lines, can be plotted to identify consistent regime patterns in the analysis of numerous reconstructions. The Z lines for the 57 reconstructions evaluated here show a common pattern of IMD cycles of drought and pluvial periods during the late 16th and 17th centuries, a relatively dormant period during the 18th century, and the reappearance of alternating dry and wet IMD periods during the 19th and early 20th centuries. Although this pattern suggests the possibility of similarly active and inactive oceanic modes in the North Pacific and North Atlantic, such centennial-scale patterns are not evident in the ORR analyses of reconstructed Pacific Decadal Oscillation (PDO), El Niño–Southern Oscillation, and North Atlantic seas-surface temperature variation. But given the inconsistency in the analyses of four PDO reconstructions the possible role of centennial-scale oceanic mechanisms is uncertain. In future research the ORR method might be applied to climate reconstructions around the Pacific Basin to try to resolve this uncertainty. Given its ability to compare regime patterns in climate reconstructions derived using different methods and proxies, the method may also be used in future research to evaluate long-term regional temperature reconstructions.

scholarly journals Optimal ranking regime analysis of TreeFlow dendrohydrological reconstructions

2015 ◽  
Vol 11 (8) ◽  
pp. 1107-1125 ◽  
Author(s):  
S. A. Mauget
Keyword(s):  
San Francisco ◽  
North Atlantic ◽  
18Th Century ◽  
Southern Oscillation ◽  
Salt Lake ◽  
Time Windows ◽  
Future Research ◽  
The North ◽  
Climate Reconstructions ◽  
Optimal Ranking

Abstract. The optimal ranking regime (ORR) method was used to identify 6–100-year time windows containing significant ranking sequences in 55 western US streamflow reconstructions, and reconstructions of the level of the Great Salt Lake and San Francisco Bay salinity during 1500–2007. The method's ability to identify optimally significant and non-overlapping runs of low- and high-rankings allows it to re-express a reconstruction time series as a simplified sequence of regime segments marking intra- to multi-decadal (IMD) periods of low or high streamflow, lake level, and salinity. Those ORR sequences, referred to here as Z-lines, can be plotted to identify consistent regime patterns in the analysis of numerous reconstructions. The Z-lines for the 57 reconstructions evaluated here show a common pattern of IMD cycles of drought and pluvial periods during the late 16th and 17th centuries, a relatively dormant period during the 18th century, and the reappearance of alternating dry and wet IMD periods during the 19th and early 20th centuries. Although this pattern suggests the possibility of similarly active and inactive oceanic modes in the North Pacific and North Atlantic, such centennial-scale patterns are not evident in the ORR analyses of reconstructed Pacific Decadal Oscillation (PDO), El Niño–Southern Oscillation, and North Atlantic sea-surface temperature variation. However, given the inconsistency in the analyses of four PDO reconstructions, the possible role of centennial-scale oceanic mechanisms is uncertain. In future research the ORR method might be applied to climate reconstructions around the Pacific Basin to try to resolve this uncertainty. Given its ability to compare regime patterns in climate reconstructions derived using different methods and proxies, the method may also be used in future research to evaluate long-term regional temperature reconstructions.

Downslope Flows on a Low-Angle Slope and Their Interactions with Valley Inversions. Part I: Observations

2008 ◽  
Vol 47 (7) ◽  
pp. 2023-2038 ◽  
Author(s):  
C. David Whiteman ◽  
Shiyuan Zhong
Keyword(s):  
Salt Lake ◽  
Temperature Inversion ◽  
Maximum Speed ◽  
Salt Lake Valley ◽  
Typical Situation ◽  
Thermally Driven ◽  
Downslope Flows ◽  
Downslope Flow ◽  
Deep Temperature ◽  
Using Data

Abstract Thermally driven downslope flows were investigated on a low-angle (1.6°) slope on the west side of the floor of Utah’s Salt Lake Valley below the Oquirrh Mountains using data from a line of four tethered balloons running down the topographic gradient and separated by about 1 km. The study focused on the evolution of the temperature and wind structure within and above the slope flow layer and its variation with downslope distance. In a typical situation, on clear, undisturbed October nights a 25-m-deep temperature deficit of 7°C and a 100–150-m-deep downslope flow with a jet maximum speed of 5–6 m s−1 at 10–15 m AGL developed over the slope during the first 2 h following sunset. The jet maximum speed and the downslope volume flux increased with downslope distance. The downslope flows weakened in the late evening as the stronger down-valley flows expanded to take up more of the valley atmosphere and as ambient stability increased in the lower valley with the buildup of a nocturnal temperature inversion. Downslope flows over this low-angle slope were deeper and stronger than has been reported previously by other investigators, who generally investigated steeper slopes and, in many cases, slopes on the sidewalls of isolated mountains where the downslope flows are not subject to the influence of nighttime buildup of ambient stability within valleys.

scholarly journals Temperature Inversion and Ultrafine Particulate/Near Ultrafine Particulate Matter Concentrations in the Salt Lake Valley

2021 ◽  
Vol 2 (7) ◽  
pp. 422-435
Author(s):  
Danielle Mecate ◽  
Rod Handy ◽  
Leon Pahler ◽  
Darrah Sleeth ◽  
Joemy Ramsay ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Health Outcomes ◽  
Salt Lake ◽  
Temperature Inversion ◽  
Linear Regression Models ◽  
Salt Lake Valley ◽  
Adverse Health Outcomes ◽  
The Mean ◽  
Ultrafine Particulate Matter ◽  
Negative Health Outcomes

Ultrafine particulate (UFP) matter exposures are associated with negative health outcomes. UFPs (<100nm) and near UFP (NUFP) matter (4.5nm - 250nm) are trapped by the bowl-like geography of the Salt Lake Valley causing winter inversions (i.e., trapped particulate matter (PM)). Enmont PUFP C100 and Grimm 1.109 particle counters were used to define NUFP concentrations during inversion (n=5) and non-inversion (n=5) days at 7 sites. NUFP concentrations served as a proxy for the UFP fraction. NUFP concentrations were log-transformed and multivariable mixed effects linear regression models determined if NUFP concentration differed between inversion and non-inversion or by length of inversion. Difference in fraction NUFP was also analyzed. The mean NUFP concentration was 1.49-fold higher during inversions (95% CI 1.11–2.02), whereas the fraction declined by 0.22 (95% CI -0.31– -0.13). Increased NUFP concentrations during inversions may lead to increased adverse health outcomes. These findings have serious implications for inversion-prone regions.

scholarly journals Lake-Breeze Fronts in the Salt Lake Valley

2007 ◽  
Vol 46 (2) ◽  
pp. 196-211 ◽  
Author(s):  
Daniel E. Zumpfe ◽  
John D. Horel
Keyword(s):  
Salt Lake ◽  
Great Salt Lake ◽  
Vertical Mixing ◽  
Salt Lake City ◽  
Lake Breeze ◽  
Salt Lake Valley ◽  
The North ◽  
Dewpoint Temperature ◽  
Lake City ◽  
Transport And Mixing

Abstract Winds at the Salt Lake City International Airport (SLC) during the April–October period from 1948 to 2003 have been observed to shift to the north (up-valley direction) between late morning and afternoon on over 70% of the days without precipitation. Lake-breeze fronts that develop as a result of the differential heating between the air over the nearby Great Salt Lake and that over the lake’s surroundings are observed at SLC only a few times each month. Fewer lake-breeze fronts are observed during late July–early September than before or after that period. Interannual fluctuations in the areal extent of the shallow Great Salt Lake contribute to year-to-year variations in the number of lake-breeze frontal passages at SLC. Data collected during the Vertical Transport and Mixing Experiment (VTMX) of October 2000 are used to examine the structure and evolution of a lake-breeze front that moved through the Salt Lake Valley on 17 October. The onset of upslope and up-valley winds occurred within the valley prior to the passage of the lake-breeze front. The lake-breeze front moved at roughly 3 m s−1 up the valley and was characterized near the surface by an abrupt increase in wind speed and dewpoint temperature over a distance of 3–4 km. Rapid vertical mixing of aerosols at the top of the 600–800-m-deep boundary layer was evident as the front passed.

scholarly journals Synoptic-Scale Environments Conducive to Orographic Impacts on Cold-Season Surface Wind Regimes at Montreal, Quebec

2012 ◽  
Vol 51 (3) ◽  
pp. 598-616 ◽  
Author(s):  
Alissa Razy ◽  
Shawn M. Milrad ◽  
Eyad H. Atallah ◽  
John R. Gyakum
Keyword(s):  
Surface Wind ◽  
Temperature Inversion ◽  
Cold Season ◽  
Temperature Structure ◽  
Synoptic Scale ◽  
Near Surface ◽  
The North ◽  
Type D ◽  
Wind Events ◽  
Northeast Wind

AbstractOrographic wind channeling, defined as dynamically and thermally induced processes that force wind to blow along the axis of a valley, is a common occurrence along the St. Lawrence River Valley (SLRV) in Quebec, Canada, and produces substantial observed weather impacts at stations along the valley, including Montreal (CYUL). Cold-season observed north-northeast (n = 55) and south-southeast (n = 16) surface wind events at CYUL are identified from 1979 to 2002. The authors partition the north-northeast wind events into four groups using manual synoptic typing. Types A and D (“inland cyclone” and “northwestern cyclone”) are associated with strong lower-tropospheric geostrophic warm-air advection and near-surface pressure-driven channeling of cold air from the north-northeast, along the axis of the SLRV. Type C (“anticyclone”) shows no evidence of a surface cyclone and thus is the least associated with inclement weather at CYUL, whereas type B (“coastal cyclone”) is associated with predominantly forced wind channeling along the SLRV. Type D of the north-northeast wind events and all south-southeast wind events exhibit similar sea level pressure patterns. The respective magnitudes of the pressure gradients in the Lake Champlain Valley south of CYUL and the SLRV play a large role in determining the favored wind direction. Soundings of the various event types illustrate substantial differences in temperature structure, with a large near-surface temperature inversion particularly prevalent in north-northeast events. The results of this study may provide guidance in forecasting winds, temperatures, and observed weather in and around the SLRV, given certain synoptic-scale regimes.

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