Air Temperature Reconstructions Research Articles

A Finnish chironomid- and chaoborid-based inference model for reconstructing past lake levels

In the present study I utilize subfossil chironomid and chaoborid distributions in surface sediments of 68 shallow lakes. The aim is to develop a calibration model for past water-level reconstructions by applying weighted averaging-partial least squares (WA-PLS) techniques and to evaluate its potential applications and limitations. This study considers water depth at sampling sites, rather than maximum lake depth. The best of the water depth models developed uses three components and has a cross-validated coefficient of determination ( r 2 jack) of 0.68 and root-mean-squared error of prediction (RMSEP) of 0.78 m. The model performance is tested on the sediment sequence of a previously studied lake from southern Finland that is known to have experienced past fluctuations in its water level. The water levels inferred are compared with results of chironomid-inferred air temperature reconstruction to ease separation of the effects of the variables. The reconstruction shows consistent results similar to those of previously published cladoceran planktonic:littoral ratios (P:Ls) from the same lake. However, the results indicate that factors other than depth and temperature, such as pollution, may possibly distort the inference results. The results suggest that in applying the midge-based water depth calibration model, it would be advantageous to use it together with an inference model for temperature and preferably in a multiproxy content where changes in water chemistry may be detected. The model can be useful in studies on past effective moisture variability that is closely related to climatic changes.

Subfossil Chironomidae (Insecta: Diptera) along a latitudinal gradient in Finland: development of a new temperature inference model

AbstractNumerical techniques were used to study chironomid distribution and abundance in lakes from a 1000 km transect in Finland, with special interest on the effect of local summer air temperatures on chironomid assemblages. The final aim of the study was to develop a chironomid‐based palaeotemperature inference model. The dataset consisted of 82 lakes (of which 77 were used in the model after deletion of outliers), with catchments spanning from boreal coniferous forests to mountain birch woodland and tundra vegetation. Numerical analysis showed that the mean July air temperature was the most significant variable explaining the distribution and abundance of chironomids in Finnish lakes. Weighted‐averaging partial least squares techniques were used to develop a palaeotemperature inference model for mean July air temperature reconstructions. The model performance statistics were favourable, with cross‐validated coefficient of determination (r2) of 0.78, root mean squared error of prediction of 0.721°C and maximum bias of 0.794°C. Based on these values, the transfer function is a valid means of performing quantitative palaeotemperature estimates in downcore studies. Copyright © 2008 John Wiley & Sons, Ltd.

Methodological basis for quantitative reconstruction of air temperature and sunshine from pollen assemblages in Arctic Canada and Greenland

This study presents a modern database including 831 pollen assemblages from lakes of the Boreal, Subarctic and Arctic biomes of North America and Greenland, and corresponding temperature, sunshine and precipitation. Pollen data include the 39 most common vascular taxa (18 woody plants and 21 herbs). Multivariate ordinations using correspondence analysis (CA) and canonical correspondence analysis (CCA) reveal that temperature and sunshine account, respectively, for 45.5% and 44.4% of the variance within pollen assemblages, whereas precipitation only accounts for 10.2% of total variance. CCA further demonstrates that the climatic information encapsulated in pollen assemblages is not the same for the three biomes. In the Boreal biome, precipitation and temperature account for most of the variance, whereas sunshine and precipitation are more determinant in the Subarctic biome, and the temperature and sunshine seem to exert the main control on the pollen distribution in the Arctic biome. The modern analogue technique (MAT) and CCA regressions were tested for reconstructing climate parameters. MAT yields better results than CCA regressions and validation tests indicate a root mean square error (RMSE) of 1.35 °C for July air temperature, 2.3% for July sunshine, 3.10 °C for January air temperature and 143 mm for annual precipitation. Two examples of reconstructions are presented from recent (<450 years) lake-sediment cores of eastern Baffin Island, Arctic Canada and southwest Greenland. They demonstrate that July air temperature and July sunshine can be reconstructed independently from Arctic pollen assemblages, but January air temperature and annual precipitation must be interpreted with caution. They also suggest that reconstruction of past sunshine variations can serve to document climate changes at synoptic scale including the North Atlantic Oscillation (NAO).

Biogenic silica concentration as a high‐resolution, quantitative temperature proxy at Hallet Lake, south‐central Alaska

High‐resolution, quantitative temperature records are valuable for placing recent warming in the context of long‐term, natural climate variability. Here we use biogenic silica (BSi) concentrations preserved in lacustrine sediment from an oligotrophic lake to quantitatively reconstruct air temperature at Hallet Lake in south‐central Alaska. Mean June through August temperature measured over the past 80 yr at Valdez (Alaska) correlate with BSi from Hallet Lake (r = 0.87, p = 0.01). We chose a nested function to model the non‐linear relation between summer temperature and BSi in the calibration data set, and to reconstruct temperature for the past 2 ka. Our BSi‐inferred temperature reconstruction shows synchronous changes with independent paleoclimatic proxies for southern Alaska, and provides evidence for a greater rate and magnitude of 20th century temperature warming at Hallet Lake than recorded by other quantitative temperature proxies in the region.

Environmental controls on modern chironomid faunas from NW Iceland and implications for reconstructing climate change

Reconstructing climate change quantitatively over millennial timescales is crucial for understanding the processes that affect the climate system. One of the best methods for producing high resolution, low error, quantitative summer air temperature reconstructions is through chironomid analyses. We analysed over 50 lakes from NW and W Iceland covering a range of environmental gradients in order to test whether the distribution of the Icelandic chironomid fauna was driven by summer temperature, or whether other environmental factors were more dominant. A range of analyses showed the main environmental controls on chironomid communities to be substrate (identified through loss-on-ignition and carbon content) and mean July air temperature, although other factors such as lake depth and lake area were also important. The nature of the Icelandic landscape, with numerous volcanic centres (many of which are covered by ice caps) that produce large quantities of ash, means that relative lake carbon content and summer air temperature do not co-vary, as they often do in other chironomid datasets within the Arctic as well as more temperate environments. As the chironomid–environment relationships are thus different in Iceland compared to other chironomid training sets, we suggest that using an Icelandic model is most appropriate for reconstructing past environmental change from fossil Icelandic datasets. Analogue matching of Icelandic fossil chironomid datasets with the Icelandic training set and another European chironomid training set support this assertion. Analyses of a range of chironomid-inferred temperature transfer functions suggest the best to be a two component WA-PLS model with r2jack = 0.66 and RMSEP = 1.095°C. Using this model, chironomid-inferred temperature reconstructions of early Holocene Icelandic sequences show the magnitude of temperature change compared to contemporary temperatures to be similar to other NW European chironomid sequences, suggesting that the predictive power of the model is good.

Testing a European winter surface temperature reconstruction in a surrogate climate

We evaluate the skill of a European winter surface air temperature reconstruction over the last 500 years using pseudoproxies obtained from the ECHO‐G and HadCM3 climate models. The emphasis is thereby on the effect of the reduction of available predictors back in time, an issue that has not yet been investigated in detail at continental and seasonal scale. It is found that the key factor in determining the reconstruction skill is the number of predictors and particularly their spatial distribution. However considering the usually insufficient spatial and temporal predictor availability in paleo‐reconstructions, the quality of the predictors becomes more important further back in time. Not surprisingly, the lowest reconstruction skill is found in the early period when the predictor network is reduced. Important differences between ECHO‐G and HadCM3‐based pseudoproxy reconstructions are discussed and implications for future analyses are presented.

Chironomid-based reconstructions of summer air temperature from lake deposits in Lyndon Stream, New Zealand spanning the MIS 3/2 transition

We present chironomid-based temperature reconstructions from lake sediments deposited between ca 26,600 cal yr BP and 24,500 cal yr BP from Lyndon Stream, South Island, New Zealand. Summer (February mean) temperatures averaged 1 °C cooler, with a maximum inferred cooling of 3.7 °C. These estimates corroborate macrofossil and beetle-based temperature inferences from the same site and suggest climate amelioration (an interstadial) at this time. Other records from the New Zealand region also show a large degree of variability during the late Otiran glacial sequence (34,000–18,000 cal yr BP) including a phase of warming at the MIS 2/3 transition and a maximum cooling that did not occur until the global LGM (ca 20,000 cal yr BP). The very moderate cooling identified here at the MIS 2/3 transition confirms and enhances the long-standing discrepancy in New Zealand records between pollen and other proxies. Low abundances (<20%) of canopy tree pollen in records from late MIS 3 to the end of MIS 2 cannot be explained by the minor (<5 °C) cooling inferred from this and other studies unless other environmental parameters are considered. Further work is required to address this critical issue.

A comparison of chironomid biostratigraphy from Lake Vuolep Njakajaure with vegetation, lake-level, and climate changes in Abisko National Park, Sweden

Chironomid remains from the sediment of Lake Vuolep Njakajaure reflect limnological conditions resulting from changing climate and vegetation throughout the Holocene, but do not strictly follow accepted climate trends or the vegetation history based on regional pollen and macrofossil analyses. Chironomid community changes appear to be influenced by organic nutrient input from the surrounding catchment vegetation and lake hydrology, both of which are indirectly responding to some combination of climate change, hypolimnetic oxygen concentration, and changes in basin morphology. The chironomid-based quantitative mean July air-temperature reconstruction differs from other regional quantitative records; this discrepancy is likely related to limnological conditions particular to Lake Vuolep Njakajaure. Comparison of a northern Swedish temperature transfer function and one from western Canada reveals differences in the mean July air-temperature optima of several common taxa, suggesting that the existing conservative estimates of Holocene climate change in northern Sweden may be underestimated due to the limited temperature gradient captured by the Swedish training set.

Anomalous early 20th century sedimentation in proglacial Green Lake, British Columbia, Canada

Annually laminated sediments were recovered from Green Lake, a proglacial lake in the southern Coast Mountains in British Columbia, to examine their potential as a temperature proxy. Varve thickness is moderately correlated with temperature anomalies (A.D. 1900–1994) and annual maximum mean daily discharge of Lillooet River (A.D. 1930–1999), but these relations are not stable through time. Following A.D. 1977, the relation between varve thickness and annual maximum mean daily discharge is stronger. Prior to A.D. 1977, varve thickness is correlated with March to October air temperature, which controls the intensity and duration of glacier runoff. Varve thickness is weakly correlated with reconstructed air temperature records for North America and the Northern Hemisphere for the period A.D. 1600–1976. Less extensive glacier cover may explain the lack of a clear temperature signal in the varved sediment record prior to A.D. 1600 and following A.D. 1977. The period of highest lake sedimentation, from A.D. 1920 to 1945, coincides with rapid retreat of glaciers in the watershed. The lack of a similar level of sedimentation in the varve chronology suggests that glacier recession during the period 1920–1945 was higher than at any time in the past 600 years.

Teleconnections between sea-surface temperature anomalies and air temperature in northeast Brazil

The relationship between sea-surface temperature (SST) and air temperature in northeast Brazil was analyzed using sea-surface temperature anomalies (SSTA) and geographic coordinates. Mean monthly time series of air temperatures (daily mean, maximum and minimum) of 69 meteorological stations and SSTA from the Atlantic (North and South), the Global Tropics and the Pacific (Niño 3 area) Oceans were analyzed within the framework of principal component analysis (PCA) and linear regression approach. The PCA model was used to identify the dominant temporal and spatial variability patterns of air temperature estimated by the SSTA model and observed air temperature in northeast Brazil. The main objective of this research was to establish a predicting model from the geographic coordinates and SSTA, capable of reconstructing air temperature time series. Data analysis indicated statistically significant correlation ( p<0.01) between SST and air temperature. This relationship was less using the SST from the Equatorial Pacific Ocean (Niño 3 area) and it also proved to be statistically significant ( p<0.01). Results also showed that air temperature in northeast Brazil can be obtained with reasonable accuracy as a function of the geographic coordinates and SSTA. A substantial amount of data variance was accounted for by the first two components. The first and the second principal components (PC) of the mean daily air temperature time series, reconstructed on the basis of the SSTA, explained 90.2% (North Atlantic), 90.7% (South Atlantic), 91.5% (Global Tropics), 92.6% (Pacific Niño 3) and 64.4% (observed data) of the data variance. The first and the second PCs have been associated with the main atmospheric systems that act in northeast Brazil.

Quantitative Calibration of Remote Mountain-Lake Sediments as Climatic Recorders of Air Temperature and Ice-Cover Duration

A combination of empirical modeling and a diatom-based transfer function was developed to reconstruct air temperature and ice-cover duration through the study of lake sediments. By using a thermal degree-day modeling approach, ice-cover duration on European mountain and sub-Arctic lakes is found to be very sensitive to temperature change. For example, our model, which incorporates a weather generator, predicts a 100-day shortening in ice-cover duration for a 3°C temperature rise for catchments at elevations of 1500 m in the Southern Alps and the Pyrenees. For the more maritime lakes of Scotland, 30% higher sensitivities (130 d per 3°C) are found, whereas lakes in northwest Finland, in a more continental setting, have only half the sensitivity (50 d per 3°C). A pan-European data set of the species abundance of 252 diatom taxa in 459 mountain and sub-Arctic lakes has been compiled and taxonomically harmonized. Transfer functions were created that relate both seasonal air temperature and ice-cover duration to diatom species composition on the basis of a weighted averaging–partial least squares (WA-PLS) approach. Cross validation was used to test the transfer functions. For ice-cover duration the pan-European data set yields an R-squared value of 0.73, a jack-knifed R-squared value of 0.58, and a residual-mean-square error of prediction (RMSEP) of 23 days. A regional, northern Fennoscandian transect (151 lakes, 122 taxa) yields a jack-knifed R-squared value of 0.50 and an RMSEP of 9 days. For air temperature the pan-European database displayed greatest skill when reconstructing winter or spring temperatures. This result contrasts with the summer temperatures normally studied when using local elevation gradients. The northern Fennoscandian transect has a remarkably low winter RMSEP of 0.73°C.

Temperature changes in Poland from the 16th to the 20th centuries

A standardized tree-ring width chronology of the Scots pine (Pinus sylvestris L.) along with different types of documentary evidence (e.g. annals, chronicles, diaries, private correspondence, records of public administration, early newspapers) have been used to reconstruct air temperature in Poland. The ground surface temperature (GST) history has been reconstructed based on the continuous temperature logs from 13 wells, using a new method developed recently by Harris and Chapman (1998; Journal of Geophysical Research103: 7371–7383) which is compared with the functional space inversion (FSI) method applied to all available Polish temperature–depth profiles analysed before. Response function calculations conducted for trees growing in Poland (except in mountainous regions) reveal a statistically significant correlation between the annual ring widths of the Scots pine and the monthly mean air temperatures, particularly from February and March, but also from January and April. Therefore, it was only possible to reconstruct the mean January–April air temperature. The following periods featured a warm late winter/early spring: 1530–90, 1656–70 (the warmest period), 1820–50, 1910–40, and after 1985. On the other hand, a cold January–April occurred in the following periods: 1600–50, 1760–75, 1800–15, 1880–1900, and 1950–80. Reconstructions of thermal conditions using documentary evidence were carried out for winter (December–February) and summer (June–August) from 1501 to 1840 and, therefore, their results cannot be directly compared with reconstructions based on tree-ring widths. Winter temperatures in this period were colder than air temperature in the 20th century. On the other hand, ‘historical’ summers were generally warmer than those occurring in the 20th century. Such situations dominated in the 16th and 17th centuries, as well as at the turn of the 18th and 19th centuries. Throughout almost the entire period from 1501 to 1840, the thermal continentality of the climate in Poland was greater than in the 20th century. GST reconstructions show that its average pre-instrumental level (1500–1778) is about 0.9–1.5 °C lower than the mean air temperature for the period 1951–81. Lower amplitude of GST warming (0.9 ± 0.1 °C) results from the individual and simultaneous inversions of well temperature data using the FSI method. A very good correspondence of the results has been found between series of annual mean GSTs from the FSI method and mean seasonal air temperatures reconstructed using documentary evidence. Copyright © 2005 Royal Meteorological Society

Climate evolution in the last five centuries simulated by an atmosphere-ocean model: global temperatures, the North Atlantic Oscillation and the Late Maunder Minimum

The main results of a transient climate simulation of the last 500 years with a coupled atmosphere-ocean model driven by estimated solar variability, volcanic activity and atmospheric concentrations of greenhouse gases are presented and compared with several empirical climate reconstructions. Along the last five centuries the climate model simulates a climate colder than mean 20th century conditions almost globally, and the degree of cooling is clearly larger than in most empirical reconstructions of global and North hemispheric near-surface air temperature (MANN et al., 1998; JONES et al., 1998). The simulated temperatures tend to agree more closely with the reconstruction of ESPER et al. (2002) based on extratropical tree-ring chronologies. The model simulates two clear minima of the global mean temperature around 1700 A.D. (the Late Maunder Minimum) and around 1820 A.D. (the Dalton Minimum). The temperature trends simulated after the recovery from these minima are as large as the observed warming in the 20th century. More detailed results concerning the simulated Late Maunder Minimum, together with a spatially resolved historical reconstruction of the temperature field in Europe, are presented. It is found that the broad patterns of temperature deviations are well captured by the model, with stronger cooling in Central and Eastern Europe and weaker cooling along the Atlantic coast. However, the model simulates an intense drop of air-temperature in the North Atlantic ocean, together with an extensive sea-ice cover south of Greenland and lower salinity in North Atlantic at high latitudes, reminiscent of the Great Salinity Anomaly. Also, during the Late Maunder Minimum the intensities of the Golf Stream and the Kuroshio are reduced. This weakening is consistent with a reduced wind-stress forcing upon the ocean surface.

Palaeolimnological and sedimentary responses to Holocene forest retreat in the Scandes Mountains, west-central Sweden

A suite of analyses was performed on sediments accumulated during the last 10 700 years in Lake Spaime, a small, hydrologically open water body in the modem alpine tundra zone of the Scandes Mountains, west-central Sweden. The study aimed to evaluate (1) the nature of climate changes that forced the late-Holocene lowering of altitudinal tree limit in the region, the timing of which is known from prior studies based on radiocarbon dating of subfossil wood, and (2) the impact of these vegetational changes on an aquatic ecosystem. Arboreal pollen and plant macrofossil data confirm the persistence of trees in the lake catchment at least from c. 9700 cal. BP until c. 3700 cal. BP. Although growing-season temperature is commonly believed to be the dominant factor driving boreal forest tree-limit variations in the region, a chironomid-based reconstruction of mean July air temperature suggests that local deforestation during the late Holocene was not accompanied by a significant cooling. The tree-limit retreat was more likely caused by increasing effective moisture and declining length of the growing season. The ecohydrological response of Lake Spaime to this combination of climate and vegetational changes included a decline in primary productivity, as indicated by an abrupt decrease in sediment organic matter content, while associated increases in organic 613C, 615N and C/N point to diminished fluxes and altered balance of catchment derived nutrients following deforestation. The decline in aquatic productivity is also marked by a distinct change in the mineral magnetic properties, from a high magnetic concentration assemblage dominated by fine-grained magnetite of biogenic origin to one dominated by background levels of coarse-grained detrital magnetite.

Holocene temperature estimates and chironomid community composition in the Abisko Valley, northern Sweden

Multi-proxy paleoenvironmental reconstructions are useful to determine the various factors affecting the biological communities of a lake, but to assess if changes in community composition of one indicator organism accurately reconstructs climatic changes through time, it may be more useful to compare temperature reconstructions using the same indicator in several lakes. Here, we compare reconstructions of mean July air temperature using chironomid-based transfer functions from Holocene records at three nearby lakes in the Abisko Valley of northern Sweden to assess if chironomids can be used as indicators of regional temperature changes. The three study lakes experience the same regional climatic conditions, but are located along gradients of elevation (348–999 m a.s.l), temperature (8.1–12°C) and terrestrial vegetation (coniferous to alpine). Chironomid-temperature reconstructions from the three sites indicate a general pattern of temperature decrease (1.5–2.4°C) during the Holocene, consistent with decreases observed from analyses of other proxies in this area, and from other alpine regions in Europe and North America. Similarities between these reconstructions suggest that chironomids can adequately record general patterns of temperature changes through the Holocene, although effects of site-specific factors such as variations in lake water pH can cause deviations in inferred temperature among sites during some periods.

Statistical downscaling in European mountains: verification of reconstructed air temperature

General circulation models constrained by past meteorological records have been run as part of a major community effort, using datasets from 1958 to the present date, to produce consistent gridded atmospheric databases known as reanalysis data. We derive linear regression models to transfer reanalysis gridded data to high elevation weather stations in Europe using daily observations from 1994 to 2001. The models are then used to reconstruct daily mean, minimum and maximum air temperatures since 1958 at the weather stations. The regression models use principal components of reanalysis temperature and pressure variables in addition to local (nearest grid point) temperature and pressure variables. An all-subsets regression technique in conjunction with cross validation is used to find the best model. The accuracy of the approach is verified using observed monthly data from 1980 to 1990 at 29 stations, and monthly data since 1958 at 8 stations. The verification results indicate that retrodiction to 1980 is good at all stations. However, validation at 3 alpine stations shows large differences between observed and reconstructed temperatures prior to 1970. Nevertheless, the basic spatio-temporal warming pattern we reconstruct for the European mountains has many simi- larities to that for the European 'lowlands'. We find regional climatic trends for the period 1958 to 2001 of typically 0.7°C per 100 yr for minimum temperatures and twice that for maximum temper- atures. These trends are probably underestimated. Our reconstructions suggest that there has been an increase in the diurnal temperature range in European mountains in addition to the overall warming.

Summer temperature in northeastern Siberia since 1642 reconstructed from tracheid dimensions and cell numbers of Larix cajanderi

We reconstructed air temperature for two periods in the growth season from cell dimension and cell number variability in cross-dated tree rings of Larix cajanderi Mayr. from northeastern Siberia. Thirteen tree-ring chronologies based on cell size, cell wall thickness, and cell number were developed for AD 1642–1993. No clear evidence was found of an age-related trend in cell dimensions in the sampled materials, but cell numbers were correlated with cambial age. The chronologies contain strong temperature signals associated with the timing of xylem growth. We obtained reliable reconstructions of mean June temperature from the total cell number and July–September temperature from the cell wall thickness of latewood. June temperature and July–September temperature covaried for most of the period from AD 1642 to AD 1978. After that time, June temperature became cooler relative to July–September temperature. This difference caused disproportional changes in earlywood tracheids because of the late start of growth and cool conditions in June followed by warming during the rest of the season. The identification of this unusual recent change has shown that intraseasonal resolution may be achieved by cell dimension and cell number chronologies.

A chironomid-based Holocene summer air temperature reconstruction from the Swiss Alps

We developed a quantitative chironomid-July air temperature inference model based on surface sediments from 81 Swiss lakes and applied it to the Holocene subfossil chironomid record of Hinterburgsee, a small subalpine lake in the northern Swiss Alps (present-day mean July air temperature of 11.3°C). After smoothing to reduce the high between-sample variability of inferred temperatures, the reconstruction indicates July air temperatures of 10.4– 10.9°C at the end of the Younger Dryas, of 11.9–12.8°C during the early and mid-Holocene (11500–4000 cal. BP), and slightly lower temperatures of 11.5–12.0°C during the late Holocene (3500–1000 cal. BP). A warming trend inferred for the past millennium is most likely an artifact of human impact on Hinterburgsee's chironomid fauna, rather than a genuine temperature signal. The most prominent climatological events during the Holocene were two periods of lower temperatures at c. 10700–10500 cal. BP and 8200–7700 cal. BP and an abrupt shift to a cooler late-Holocene climate around 4000–3700 cal. BP. Although the chironomid-inferred climate signals were within the prediction error of the model (1.51°C), major inferred temperature changes agree well with other northern and central European climate reconstructions and underline the potential of subfossil chironomid analysis to reconstruct even the moderate climatic changes within the Holocene.

Comments on the paper of R. N. Harris and D. S. Chapman “Mid‐latitude (30°N–60°N) climatic warming inferred by combining borehole temperatures with surface air temperatures”

Harris and Chapman [2001; hereafter HC2001] recently presented a comparison between ground temperature records (temperature–depth profiles measured in many boreholes) and surface air temperature observations and reconstructions. Research such as theirs, attempting to reconcile or compare climate proxies that have high temporal resolution with those that have much lower temporal resolution, is important because it provides a way of assessing the fidelity with which the high-resolution proxies capture multicentury climate variability [Briffa and Osborn, 1999, highlighted some potential difficulties at capturing such long time scale variations]. Unfortunately, the paper by HC2001 contains a conspicuous error that requires highlighting in order that their results can be re-evaluated, but also to prevent the error from propagating in the literature.

Ice core evidence of rapid air temperature increases since 1960 in alpine areas of the Wind River Range, Wyoming, United States

Site‐specific transfer functions relating delta oxygen 18 (δ18O) values in snow to the average air temperature (TA) during storms on Upper Fremont Glacier (UFG) were used in conjunction with δ18O records from UFG ice cores to reconstruct long‐term trends in air temperature from alpine areas in the Wind River Range, Wyoming. Transfer functions were determined by using data collected from four seasonal snowpacks (1989–1990, 1997–1998, 1998–1999, and 1999–2000). The timing and amount of each storm was determined from an automated snowpack telemetry (SNOTEL) site, 22 km northeast of UFG, and ∼1060 m in elevation below UFG. Statistically significant and positive correlations between δ18O values in the snow and TA were consistently found in three of the four seasonal snowpacks. The snowpack with the poor correlation was deposited in 1997–1998 during the 1997–1998 El Niño Southern Oscillation (ENSO). An ultrasonic snow‐depth sensor installed on UFG provided valuable insights into site‐specific storms and postdepositional processes that occur on UFG. The timing of storms recorded at the UFG and Cold Springs SNOTEL sites were similar; however, selected storms did not correlate. Snow from storms occurring after mid‐October and followed by high winds was most susceptible to redeposition of snow. This removal of lower temperature snowfall could potentially bias the δ18O values preserved in ice core records to environmental conditions reflecting higher air temperatures and lower wind speeds. Transfer functions derived from seasonal snow cover on UFG were used to reconstruct TA values from δ18O values determined from two ice cores collected from UFG. Reconstructed air temperatures from the ice core data indicate an increase in TA of ∼3.5°C from the mid‐1960s to the early 1990s in the alpine areas of northwestern Wyoming. Reconstructed TA from the ice core records between the end of the Little Ice Age (LIA), mid‐1800s, and the early 1990s indicate a TA increase of ∼5°C. The historically reconstructed TA values from the UFG were significantly higher than the global average observed during the 20th Century but were in agreement with TA increases observed at selected, high‐altitude and high‐latitude sites in other parts of the world. Additional research is required to determine if part of the observed trend toward heavier δ18O values in ice from the UFG since the LIA (and increased TA) is due to an increased proportion of snowfall from southerly storm tracks and moisture sources, as seems to have been the situation in 1997–1998.