A comparison of surface and free-air temperature variability and trends at radiosonde sites and nearby high elevation surface stations

2007 ◽  
Vol 27 (11) ◽  
pp. 1519-1529 ◽  
Author(s):  
N. C. Pepin ◽  
W. Duane
Keyword(s):  
Air Temperature ◽  
High Elevation ◽  
Temperature Variability ◽  
Free Air

scholarly journals Spatial representativity of air-temperature information from instrumental and ice-core-based isotope records in the European Alps

2002 ◽  
Vol 35 ◽  
pp. 157-161 ◽  
Author(s):  
Wolfgang Schöner ◽  
Ingeborg Auer ◽  
Reinhard Böhm ◽  
Lothar Keck ◽  
Dietmar Wagenbach
Keyword(s):  
Air Temperature ◽  
Ice Core ◽  
Ice Cores ◽  
Summer Precipitation ◽  
High Elevation ◽  
Summer Temperature ◽  
Temperature Variability ◽  
Temperature Record ◽  
European Alps

AbstractSpatial correlations between Alpine high-elevation and European low-elevation instrumental air temperatures are computed to assess the spatial representativity of a high-Alpine ice-core isotope proxy temperature record. the correlation analyses indicate that air-temperature records at Alpine ice-core drill sites are representative for central Europe, particularly in summer. While Alpine ice cores generally show a large scattering in the conserved section of the year, long-term records from low-accumulation sites consist almost solely of summer precipitation and thus reflect isotope proxy summer-temperature variability. However, correlation between seasonal and annual instrumental air temperature indicates that summer temperature variability provides an adequate approach to annual temperature variability. Comparison of long-term ice-core δ18O records from Colle Gnifetti (4450ma.s.l.), Monte Rosa, Western Alps, with local instrumental summer temperatures inferred from an instrumental network shows good agreement in the long-term scale. Thus Alpine long-term ice-core δ18O records are representative for central European air-temperature variability.

Air temperature variability in high-elevation glacierized regions: observations from six catchments on the Tibetan Plateau

2021 ◽  
Keyword(s):  
Tibetan Plateau ◽  
Air Temperature ◽  
High Elevation ◽  
Temperature Variability ◽  
The Tibetan Plateau ◽  
Katabatic Winds ◽  
Near Surface ◽  
Southeastern Tibetan Plateau ◽  
Air Temperatures ◽  
Cooling Effects

Abstract Near-surface air temperature variability and the reliability of temperature extrapolation within glacierized regions are important issues for hydrological and glaciological studies that remain elusive because of the scarcity of high-elevation observations. Based on air temperature data in 2019 collected from 12 automatic weather stations, 43 temperature loggers and 6 national meteorological stations in six different catchments, this study presents air temperature variability in different glacierized/nonglacierized regions and assesses the robustness of different temperature extrapolations to reduce errors in melt estimation. The results show high spatial variability in temperature lapse rates (LRs) in different climatic contexts, with the steepest LRs located on the cold-dry northwestern Tibetan Plateau and the lowest LRs located on the warm-humid monsoonal-influenced southeastern Tibetan Plateau. Near-surface air temperatures in high-elevation glacierized regions of the western and central Tibetan Plateau are less influenced by katabatic winds and thus can be linearly extrapolated from off-glacier records. In contrast, the local katabatic winds prevailing on the temperate glaciers of the southeastern Tibetan Plateau exert pronounced cooling effects on the ambient air temperature, and thus, on-glacier air temperatures are significantly lower than that in elevation-equivalent nonglacierized regions. Consequently, linear temperature extrapolation from low-elevation nonglacierized stations may lead to as much as 40% overestimation of positive degree days, particularly with respect to large glaciers with a long flowline distances and significant cooling effects. These findings provide noteworthy evidence that the different LRs and relevant cooling effects on high-elevation glaciers under distinct climatic regimes should be carefully accounted for when estimating glacier melting on the Tibetan Plateau.

scholarly journals A Comparison of SNOTEL and GHCN/CRU Surface Temperatures with Free-Air Temperatures at High Elevations in the Western United States: Data Compatibility and Trends

2005 ◽  
Vol 18 (12) ◽  
pp. 1967-1985 ◽  
Author(s):  
N. C. Pepin ◽  
M. Losleben ◽  
M. Hartman ◽  
K. Chowanski
Keyword(s):  
Air Temperature ◽  
Temperature Difference ◽  
Warming Trend ◽  
High Elevation ◽  
Climatic Research Unit ◽  
Mountain Areas ◽  
Temperature Anomalies ◽  
Surface Temperatures ◽  
Air Temperatures ◽  
Free Air

Abstract This paper compares high-elevation surface temperatures based on the Global Historical Climate Network/Climatic Research Unit (GHCN/CRU) and snow telemetry (SNOTEL) datasets, with simultaneous free-air equivalent temperatures, interpolated from NCEP–NCAR reanalysis. Mean monthly temperature anomalies from 1982 to 1999 are examined for 60 SNOTEL and 296 GHCN/CRU sites at elevations over 500 m with relatively homogenous records. The surface/free-air temperature difference ΔT (Ts − Ta) is calculated for both the SNOTEL and GHCN/CRU datasets. Topography influences the correlation between surface and free-air temperature anomalies. Physically realistic diurnal and seasonal changes in ΔT\E are illustrated. Systematic secular trends in surface temperatures, free-air temperatures, and ΔT are revealed, but the sign and magnitude of change depends on location, meaning that regional signals are weak. The Ts trends are positive for most GHCN and CRU sites, and for SNOTEL sites at night. Daytime cooling in the SNOTEL network reduces the mean daily warming trend. The Ta trends are consistently positive for both networks and are often larger than Ts. Thus mean ΔT trends are negative for both datasets. The smaller sample size in the SNOTEL dataset means that error estimates for regional signals are much wider than for the GHCN/CRU dataset. Trend difference maps identify potentially anomalous SNOTEL records. Trends show no correlation with elevation and topography. Surface trends show higher variability and account for most of the uncertainty in ΔT trends. Sensitivity of trends to time period is also discussed. Such changes in the free-air/surface temperature difference may indicate change in the energy balance of mountain areas.

Comparison of Vertical Soundings and Sidewall Air Temperature Measurements in a Small Alpine Basin

2004 ◽  
Vol 43 (11) ◽  
pp. 1635-1647 ◽  
Author(s):  
C. David Whiteman ◽  
Stefan Eisenbach ◽  
Bernhard Pospichal ◽  
Reinhold Steinacker
Keyword(s):  
Air Temperature ◽  
Land Use Planning ◽  
Lower Cost ◽  
Temperature Inversion ◽  
Eastern Alps ◽  
Static Stability ◽  
Good Correspondence ◽  
Temperature Bias ◽  
Air Temperatures ◽  
Free Air

Abstract Tethered balloon soundings from two sites on the floor of a 1-km-diameter limestone sinkhole in the eastern Alps are compared with pseudovertical temperature “soundings” from three lines of temperature dataloggers on the basin's northwest, southwest, and southeast sidewalls. Under stable nighttime conditions with low background winds, the pseudovertical profiles from all three lines were good proxies for free air temperature soundings over the basin center, with a mean nighttime cold temperature bias of about 0.4°C and a standard deviation of 0.4°C. Cold biases were highest in the upper basin where relatively warm air subsides to replace air that spills out of the basin through the lowest-altitude saddle. On a windy night, standard deviations increased to 1°–2°C. After sunrise, the varying exposures of the dataloggers to sunlight made the pseudovertical profiles less useful as proxies for free air soundings. The good correspondence between sidewall and free air temperatures during high-static-stability conditions suggests that sidewall soundings can be used to monitor temperatures, temperature gradients, and temperature inversion evolution in the sinkhole. Sidewall soundings can produce more frequent profiles at lower cost than can tethersondes or rawinsondes, and extension of these findings to other enclosed or semienclosed topographies may enhance future basic meteorological research or support applications studies in agriculture, forestry, air pollution, and land use planning.

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