Cover Duration Research Articles

Analyzing the Effects of Growing Season Length on the Net Ecosystem Production of an Alpine Grassland Using Model\u2013Data Fusion

Alpine ecosystems are, similar to arctic ecosystems, characterized by a very long snow season. Previous studies investigating arctic or alpine ecosystems have shown that winter CO2 effluxes can dominate the annual balance and that the timing and duration of the snow cover plays a crucial role for plant growth and phenology and might also influence the growing season ecosystem CO2 strength and dynamics. The objective of this study was to analyze seasonal and annual CO2 balances of a grassland site at an elevation of 2440 m a.s.l in the Swiss central Alps. We continuously measured the NEP using the eddy covariance method from June 2013 to October 2014, covering two growing seasons and one winter. We analyzed the influence of snow melt date on the CO2 exchange dynamics at this site, because snow melt differed about 24 days between the 2 years. To this end, we employed a process-based ecosystem carbon cycling model to disentangle the co-occurring effects of growing season length, environmental conditions during the growing season, and physiological/structural properties of the canopy on the ecosystem carbon balance. During the measurement period, the site was a net sink for CO2 although winter efflux contributed significantly to the total balance. The cumulative growing season NEP as well as mean and maximum daily CO2 uptake rates was lower during the year with the later snow melt, and the results indicated that the differences were mainly due to differing growing season lengths.

Vulnerability analysis of the rare and endangered woodland fern Polystichum braunii in Germany: three possible causes of population decline

Background: Various rare and endangered temperate ferns are being threatened by their recent population decline, but there is limited understanding of the causes behind it.Aims: This study attempted to identify the possible drivers of regional population decline and extinction in the globally distributed woodland fern Polystichum braunii.Methods: A comparison was undertaken of the climatic, edaphic and phytosociological characteristics of sites with increasing, decreasing or recently extinct populations in Germany.Results: A significantly higher frequency of episodes of low relative air humidity (<60%) was found at sites with decreasing or extinct populations compared to habitats with population increases. Sites with decreasing or extinct populations were also characterised as having less summer precipitation (<500 mm year−1) and a shorter duration of snow cover (<110 days year−1) than sites with increasing populations. The latter had significantly higher moss cover (56% of the forest floor), but less cover by a tree litter layer (23%) compared to decreasing (36% and 38%) or recently extinct populations (22% and 52%). All increasing populations were located in intact Tilia – Acer ravine forests, while those suffering population decline were mostly located in Fagus-dominated forests.Conclusions: It was concluded that the probable causes of the recent decline in German P. braunii populations are reduced air humidity levels, decreasing snow duration or a shift from moss-covered to tree litter-covered forest floors due to climate warming or altered forest management.

Abstract 2494: ATR inhibitor AZD6738 as monotherapy and in combination with olaparib or chemotherapy: defining pre-clinical dose-schedules and efficacy modelling

Abstract Introduction: AZD6738 is a potent and selective oral inhibitor of the ataxia telangiectasia and rad3 related (ATR) protein kinase. ATR has a key role in the DNA replication stress response (RSR) pathway of DNA repairby facilitating the recovery and repair of potentially cytotoxic persistent, stalled DNA replication forks. Inhibition of ATR leads to the inability to resolve replication associated damage and the accumulation of DNA strand breaks, which if remains unrepaired leads to cell death. AZD6738 is currently in Phase I/II clinical trials being evaluated as a monotherapy and in combination with novel agents olaparib / Lynparza (PARP DNA damage response inhibitor), durvalumab (PD-L1 immune checkpoint inhibitor) and DNA-damaging agents such as carboplatin and ionising radiation. Critical in helping to guide the clinical usage of AZD6738 and maximise patient benefit, pre-clinical studies were performed to determine optimal doses and schedules as monotherapy and in combination with olaparib and carboplatin. Experimental procedures: Human cancer cell lines, xenograft and patient-derived explant (PDX) models of non-small cell lung cancer (NSCLC), head &amp; neck squamous cell carcinoma (HNSCC), and triple-negative breast cancer (TNBC) were tested comparing once daily versus twice daily dosing, the number of consecutive days dosing (3 days/week, 5 days/week, continuous) and co-dosing versus sequential or intermittent dosing with AZD6738 alone or in combination with olaparib or carboplatin. The magnitude and duration of anti-tumour responses were then compared with AZD6738 mouse pharmacokinetic (PK), pharmacodynamic (PD) and in vitro target (IC) / growth inhibition (GI) profiles. Results: A mathematical model was derived which adequately described the AZD6738 PK/PD-efficacy relationship. This modelling confirms that duration of cover (time) above cellular ATR target inhibition thresholds (IC90 pCHK1 / GI90) per day, rather than Cmax or exposures per se, is the major determinant of anti-tumour responses. As monotherapy, in sensitive ATM-deficient models, it is necessary to inhibit ATR continuously to give tumour stabilisation, which can be achieved through repeat daily of AZD6738 over several weeks. Co-dosing AZD6738 in combination with olaparib or carboplatin gives best efficacy compared to sequential dosing and PK cover over the first 48-72 hours is necessary to give tumour regressions. The models predict that extending the duration of ATR cover, achieved through repeat daily dosing, further increases efficacy. These pre-clinical dose-schedules were compared to human free plasma AZD6738 PK data and predicted efficacious exposures found to be clinically achievable. Conclusions: Together these data further support the clinical evaluation of AZD6738 and suggest optimal dosing schedules for ATR inhibitors. Citation Format: Alan Y. Lau, James Yates, Zena Wilson, Lucy A. Young, Adina M. Hughes, Alienor Berges, Amy Cheung, Rajesh Odedra, Elaine Brown, Mark J. O'Connor, Simon Hollingsworth. ATR inhibitor AZD6738 as monotherapy and in combination with olaparib or chemotherapy: defining pre-clinical dose-schedules and efficacy modelling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2494. doi:10.1158/1538-7445.AM2017-2494

Reliability of temperature signal in various climate indicators from northern Europe.

We collected relevant observational and measured annual-resolution time series dealing with climate in northern Europe, focusing in Finland. We analysed these series for the reliability of their temperature signal at annual and seasonal resolutions. Importantly, we analysed all of the indicators within the same statistical framework, which allows for their meaningful comparison. In this framework, we employed a cross-validation procedure designed to reduce the adverse effects of estimation bias that may inflate the reliability of various temperature indicators, especially when several indicators are used in a multiple regression model. In our data sets, timing of phenological observations and ice break-up were connected with spring, tree ring characteristics (width, density, carbon isotopic composition) with summer and ice formation with autumn temperatures. Baltic Sea ice extent and the duration of ice cover in different watercourses were good indicators of winter temperatures. Using combinations of various temperature indicator series resulted in reliable temperature signals for each of the four seasons, as well as a reliable annual temperature signal. The results hence demonstrated that we can obtain reliable temperature information over different seasons, using a careful selection of indicators, combining the results with regression analysis, and by determining the reliability of the obtained indicator.

Characteristics of the snow cover distribution on the coast of Lake Baikal

The paper presents results of studies of the dynamics of snow cover characteristics along the Lake Baikal coast for the years 1961–2009. Statistical characteristics of the following elements: snow depth, duration of the period with snow cover, dates of onset and destruction of snow cover, were calculated from data of local meteorological stations. Mean annual snow depth in the region varies from 1 to 36 cm, while the maximal ten-day values changes from 12 cm on the West coast up to 60–86 cm on the East coast. Mean duration of the snow cover in the Baikal region is 138 days, while on the East coast it lasts for 178 days, and on the West one – for 126 days. Long-term trends of the snow cover characteristics are mostly statistically insignificant. However, at the end of the above period dates of the snow cover onset and destruction has been shifted to earlier dates. The inter-annual variability of these dates reaches 30 days. A linear dependence of the snow cover depth on the mean air temperature and the precipitation amount for the cold season was revealed with correlation coefficients from 0.31 to 0.89.

Snow cover on the Lagonaky high plateau (Western Caucasus)

The paper presents characteristics of a snow cover observed on the Lagonaky high plateau (the Western Caucasus) in the interfluve of the rivers Belaya and Pshekha along two snow-measuring courses. The period of observations is 1973–2015, and the altitude interval is 460–2020 m. The characteristics measured are the following: depths of snow cover, the snow density, and temperature of different snow layers in the test pits. The stratigraphy of the snow thickness is described. In different years, observations did show changes in the depths which felt within a wide range of values from a few centimeters up to 5–6 m at the same points. The observations allowed determination of dates of snow appearance (setting-up of snow cover) as well as the disappearance in different parts of the Lagonaky high plateau. Durations of the snow cover in different altitudinal belts were also determined. By the end of March the snow cover disappears to altitudes of 700 m, and after 20th of April the slopes become free of snow to 1000 m. The snow cover duration in the low-altitude zone (500–1000 m) is 70–80 days, while in the middle altitudes (1,000–1,500 m) it is 130 days. In the highlands (above 2000 m), the snow cover lasts for 215 days. It must be emphasized that during the last five years the duration of snow cover has changed significantly. Materials of snow surveys showed that snow depths and water contents (water equivalents of snow cover) significantly differ from year to year. In seasons 1975/76, 1978/79, 19861/87, 1989/90 the winters were extremely snowy, while winters in 1976/77, 1979/80, 1983/84, 1990/91, 2013–2015 had small amount of snow. According to data of distant snow-measuring sticks, the maximum values of the snow depth (610 cm) have been recorded in March of 1976 near the tourist shelter Fisht (1596 м). Significant changes in the distribution of snow cover in recent years were probably related to the global climate changes.

How alpine heathlands response to the snow cover change on the ski slope? Long-lasting ski slope impact case study from the Hrubý Jeseník Mts (Central Europe)

The distribution and duration of snow cover are important variables that affect ecosystem processes in the alpine zone. The establishment of ski resorts dramatically change their surrounding environment and ski slopes represent significant anthropogenic impact in the mountains. We assessed the changes in environmental factors, phenology, growth, and reproductive performance of bilberry (&lt;em&gt;Vaccinium myrtillus&lt;/em&gt;), a dominant species of alpine heathlands, caused by a “nature-friendly” managed ski slope (i.e., without artificial snow and machine grading) at permanent plots established on the ski slope under operations (inside the ski slope) and on an unaffected control area (outside the ski slope). A lower mean temperature and a shorter time of great temperature fluctuation during snow melting, a longer time span of snow cover, and a higher snow water equivalent were observed inside the ski slope compared to outside it. Due to changed environmental conditions, the beginning of growth was postponed, and a delay in phenological development was observed in the bilberry at the ski slope. However, bilberry ripened both inside and outside the ski slope in a similar period and showed similar cover and even higher flower and fruit densities inside the ski slope compared with natural surroundings. The persistence of bilberry was not deteriorated and its performance was even better inside the ski slope. On the ski slope, managed snow cover can reduce the potential vegetation shifts due to expected impact of the climate warming. That should be taken into account in conservation and management planning.

Plant community response to nitrogen and phosphorus enrichment varies across an alpine tundra moisture gradient

Background: The extent to which nutrient availability influences plant community composition and dynamics has been a focus of ecological enquiry for decades.Aims: Results from a long-term nitrogen (N) and phosphorus (P) addition experiment in alpine tundra were used to evaluate the importance of the two nutrients in structuring plant communities in three communities that differed in their snow cover amounts and duration and soil moisture characteristics.Methods: A factorial N and P experiment was established in three meadows differing in initial vegetation composition and soil moisture. Plant and soil characteristics were measured after 20 years, and the dissimilarity among meadows and treatments were measured using permutational analysis of variance.Results: Plant species richness declined uniformly across the three meadow types and in response to N and N + P additions, while both evenness and the Shannon diversity index finding indicated that nutrient additions had the highest impact on moister habitats. Overall, N impacts overshadowed changes attributed to P additions, and the N and N + P plots in wet meadow sites were the least diverse and scored the lowest dissimilarity averages among treatments. Dissimilarity estimates indicated that the control and P plots in the dry meadow community were more distinct in composition than all other plots, and especially those in the moist or wet meadows. Above-ground biomass of grasses and sedges (graminoids) increased with N additions while forbs appeared to show responses dictated in part by the graminoid responses. The most abundant grass species of moist and wet meadow, Deschampsia cespitosa, dominated N and N + P plots of the wet sites, but did not show a N response in moist areas in spite of its general abundance in moist meadow. Competition from other plant species in the moist areas likely diminished the D. cespitosa response and contributed to the resilience of the community to nutrient enrichment.Conclusions: Initial community composition, as influenced by the specific moisture regime, appears to control the extent to which changes in nutrient resources can alter plant community structure. Long-term fertilization tends to support most but not all findings obtained from shorter-termed efforts, and wet meadows exhibit the largest changes in plant species numbers and composition when chronically enriched with N.

Changes in the snow water equivalent in mountainous basins in Slovakia over recent decades

Abstract. Changes in snowpack and duration of snow cover can cause changes in the regime of snow and rain-snow induced floods. The recent IPCC report suggests that, in snow-dominated regions such as the Alps, the Carpathian Mountains and the northern parts of Europe, spring snowmelt floods may occur earlier in a future climate because of warmer winters, and flood hazards may increase during wetter and warmer winters, with more frequent rain and less frequent snowfall. The monitoring and modelling of snow accumulation and snow melting in mountainous catchments is rather complicated, especially due to the high spatial variability of snow characteristics and the limited availability of terrestrial hydrological data. An evaluation of changes in the snow water equivalent (SWE) during the period of 1961–2010 in the Upper Hron river basin, which is representative of the mountainous regions in Central Slovakia, is provided in this paper. An analysis of the snow cover was performed using simulated values of the snow water equivalent by a conceptual semi-distributed hydrological rainfall-runoff model. Due to the poor availability of the measured snow water equivalent data, the analysis was performed using its simulated values. Modelling of the SWE was performed in different altitude zones by a conceptual semi-distributed hydrological rainfall-runoff model. The evaluation of the results over the past five decades indicates a decrease in the simulated snow water equivalent and the snow duration in each altitude zone and in all months of the winter season. Significant decreasing trends were found for December, January and February, especially in the highest altitude zone.

The influence of atmospheric circulation on the formation of snow cover on the north eastern Siberia

Based on daily data of the five meteorological stations located in different parts of northeastern Siberia (Anadyr, Chokurdakh, Wrangell Island, Verkhoyansk, Markovo) the change of dates of formation, occurrence and maximum snow depth from year to year for the entire period of observation to 2008 is analyzed. The results are compared with long-term changes of the atmospheric circulation in the Northern Hemisphere and in a particular region (according to classification by B.L. Dzerdzeevskii, V.M. Kurganskaya and Z.M. Vitvitskaya). The differences in the fluctuations of selected indicators in circulation epochs are considered. The types of circulation, contribute to early or late formation of snow cover, as well as early or late it outright are identified. Macro-circulation processes which correspond with snowy or little snowy winters are defined. Time changing of maximum snow depth formation is considered. The change in frequency of extreme values of considered characteristics par circulation epochs and their relationship with macro-circulation processes, including possible tends, are analyzed. During recent years, in the Northeastern Siberia with sharp inter-annual fluctuations of atmosphere processes the later dates of setting and earlier dates of disappearance of snow cover dominate, which reduces the duration of snow cover, in comparison with long-term average. Maximum snow depth in all stations, except Anadyr, are above the average long-term value. There is a trend of increase the maximum snow depth, its duration, as well as its later formation, compare with the average, which indicates the increase in proportion of solid precipitation at the end of winter. These are facilitated by increasing of blocking atmospheric processes duration.

Zaleganie pokrywy śnieżnej i jego zmienność w polskiej części Sudetów i na ich przedpolu

Zaleganie pokrywy śnieżnej i jego zmienność w polskiej części Sudetów i na ich przedpolu

Variability and Trends in the Duration and Depth of Snow Cover in Iran in Thirty Years

This study investigates the changes and variability of the number of days with snow cover of ≥ 1 cm depth and the seasonal maximum snow cover depth at 28 meteorological stations throughout Iran, spanning a period of 30 (1981-82 to 2010-2011) to 15 (1996-97 to 2010-2011) Winter seasons. Investigation of spatial variability of parameters using GIS map shows that maximum of the snow depth and the number of days with snow cover belongs to Koohrang station in Zagros mountains about 69.4 cm and 2457 days in 15 winter season, respectively. A decreasing trend of snow cover in the 30 winter seasons is observed in areas with abundant snow cover in highland stations. However, the scale of the snow cover change is not proportional to the air temperature changes in the most stations.

Cascading Effects of Climate Change on Forest Ecosystems: Biogeochemical Links Between Trees and Moose in the Northeast USA

The relationship between herbivores, plants and nutrient dynamics, has been investigated in many systems; however, how these relationships are influenced by changing climate has had much less attention. In the northeastern USA, both moose populations and winter climate have been changing. Moose, once extirpated from the region, have made a comeback; while locally, snow depth and duration of snow cover have declined. There is considerable uncertainty in how these changes will interact to influence forested systems. We used small experimental plots and transects along with snow removal (to elicit soil freezing and expose potential forage plants), mechanical browsing, and fecal additions (labeled with 15N) to examine ecosystem responses. We found that snow removal changed moose browsing behavior, with balsam fir more heavily browsed than sugar maple or Viburnum under low snow conditions. Soil freezing alone did not significantly alter N dynamics or selected plant responses, but there were significant interactions with moose activity. The combined effects of moose fecal additions, mechanical browsing, and soil freezing resulted in higher levels of NO3 − leaching under fir and maple, whereas Viburnum had essentially no response to these multiple factors. Our results suggest that declines in snow depth can initiate a cascade of ecosystem responses, beginning with exposure of plants to increased browsing that then triggers a series of responses that can lead to higher N losses, precipitated by decreased N demand in plants compromised by soil freezing damage. Balsam fir may be particularly susceptible to this cascade of multiple stresses.

Effects of regional climate changes on the planktonic ecosystem and water environment in the frozen Notoro Lagoon, northern Japan

Diatom fossils from core sediments and living diatoms from water samples of Notoro Lagoon in northern Japan were examined to evaluate natural climate effects on lagoon environmental changes. In 1974, the artificial inlet was excavated. Immediately after, the anoxic bottom water in Notoro Lagoon began to disappear due to an increasing water exchange rate. However, chemical oxygen demand (COD) in the bottom water of Notoro Lagoon gradually increased, with fluctuations, during the last 30 years. In addition, the dominant diatom assemblages in Notoro Lagoon shifted to ice-related and spring bloom taxa after the excavation. The dominant taxa of each year in the sediment core were also strongly related to the timing of lagoon ice melting. This is because the COD in Notoro Lagoon was affected by the deposited volume of blooming diatoms, which was controlled by the duration of ice cover and the timing of ice discharge to the Okhotsk Sea likely due to an air pressure pattern change over the northern North Pacific like the Pacific Decadal Oscillation (PDO).

Water soluble carbohydrates and growth potential of winter wheat as influenced by weather conditions during winter

Although winter survival of winter wheat most often is recorded qualitatively by rating dead or living plants, the surviving plants may differ extensively in vigour and degree of carbohydrate reserves left at the end of winter. This factor is yet not accounted for in existing models of winter wheat yield and crop performance. A quantitative measure of plant vigour at spring arrival, as influenced by the prevailing winter weather and the plants’ concentration of water soluble carbohydrates, would hence make a useful supplement to such models. Two cultivars of winter wheat were grown in boxes over 2 years at three sites in Norway with contrasting winter climates. Plants were sampled monthly for measurements of growth potential and analyses of reserve carbohydrates. Fructan constituted the main part of water soluble carbohydrates (WSC). The concentration of fructan fell throughout winter, but increased rapidly after snow thaw in spring when a positive carbon balance was restored. Daily global radiation at plant level and soil temperature (2 cm) were the only two climatic factors found to have significant effects on periodic changes in fructan concentration in a stepwise regression analysis. Still, number of days with snow cover had a causal effect through its impact on soil temperature and radiation at plant level. In neither of the 2 years was there any significant correlation between plant carbohydrate concentration and growth potential at the different sites. The results implied that plant vigour at the end of winter was strongly related to plant condition in late autumn and duration of snow cover in winter. Plants that had been covered with snow for a long time period showed significantly lower growth at the samplings in March and April than plants from the location with a shorter duration of snow cover.

Modification of SNTHERM Albedo Algorithm and Response from Black Carbon in Snow

We carried out numerical experiments of snow accumulation and depletion as well as snow albedo for a SNOw pack TELemetry (SNOTEL) site, using a one-dimensinal energy and mass balance snow model (SNTHERM) and a two-stream, multi-layer Snow, Ice, and Aerosol Radiation model (SNICAR). We developed SNTHERM_SNICAR model by replacing the snow albedo algorithm in SNTHERM with SNICAR algorithm, to improve understanding of snow accumulation and snowpack ablation processes and response from black carbon (BC) in snow. Model was tested against observed snow water equivalent (SWE) during the water year 2000 and 2002. Results show that both models do a very good job at predicting SWE, although underestimates and earlier melt-out happen. Snow albedo got from SNTHERM_SNICAR model is lower than that got from SNTHERM. Decrease in albedo, duo to BC mixed in snow, leads to faster snowmelt process and shorter duration of snow cover.

The median winter snowline in the Alps

The relative duration of snow cover in a season is a number between zero and unity; here it represents the probability to encounter, at a given station, snow of at least 5 cm depth. We use routine station data of snow depth for the winters 1961-2000 to explore the pattern of relative snow duration in the Alps. A horizontal isoline is drawn across all stations that exhibit 50 % snow duration; we consider this isoline the median snowline. We further introduce the mountain temperature as linear expansion of the Central European temperature with respect to station coordinates; it separates the large-scale European temperature from the local-scale vertical lapse rate and serves as substitute for the station temperature. The mountain temperature allows to condense the snow data of all stations and years into one analytical curve, the state function of snow duration. This curve yields every desired snowline; the median snowline coincides with the altitude of maximum sensitivity of snow duration to European temperature. The median snowline in winter is located at an average altitude of 641 m and slightly slopes downward towards the eastern Alps. The average altitude varies considerably from winter to winter under the influence of European temperature fluctuations; it shifts upward by about 123 m per °C climate warming.

Limnological measures related to climate change in the Hubbard Brook Valley, USA

Long-term monitoring within the Hubbard Brook Valley revealed changes in many climate and limnological variables known to affect the structure and function of aquatic ecosystems. The Hubbard Brook Valley is located in the White Mountains of New Hampshire, USA, and is the site of integrated, long-term ecological, biogeochemical, and hydrological studies. Mean annual temperatures in 2 headwater streams on south-facing slopes of the Hubbard Brook Valley declined ~2 °C from 1966 to 1983 and then showed a small (~1 °C) and variable increase thereafter. No significant change in temperature was observed in 3 north-facing, headwater streams. Reliable records of ice-in and ice-out have been maintained since 1968 for Mirror Lake at the base of the Hubbard Brook Valley. The duration of ice cover on Mirror Lake has declined since 1968 at a significant rate of about −0.475 d/yr as a result of earlier ice-out (0.203 d/yr) rather than later ice-in dates. Since about 1996 the duration of ice cover has become much more variable with a nonsignificant change in ice cover duration. Evaluating how various temperature-sensitive components of aquatic ecosystems in the Hubbard Brook Valley change (amount and timing) in the future will be important to developing a better understanding of limnological responses to climate change.

Vegetation–environment interactions in a sub-arctic primary succession

Biological modification of the physical environment is a characteristic feature of primary succession that is of particular importance in stressful, high-latitude habitats. However, the degree of spatiotemporal variability in biotic reaction is poorly understood. This is a significant gap in our knowledge of primary succession, as spatiotemporal variability in biotic reaction may be linked to divergent development during succession. The aim of this research was to infer long-term, spatiotemporal changes in vegetation and environmental parameters during primary succession from a chronosequence of lava flows in Iceland. Vegetation surveys and measurement of key environmental variables (temperature, relative humidity and wind speed) were carried out on seven lava flows aged 26–848 years. The duration of snow cover was inferred from temperature data using a novel technique. Paired measurements were taken in topographical low and high points, as previous studies in this location have indicated divergent vegetation development according to topographical position. The analysis indicated the long-term amelioration of microclimate. Vegetation development was associated with increased soil temperatures, decreased wind speeds and increased duration of snow-lie. There was also evidence that microenvironmental changes paralleled changes in vegetation structure, although the relationship varied according to the environmental parameter studied. It is likely that positive feedback between shrub development and snow accumulation structures the vegetation on the study sites. These findings have implications for sub-arctic areas where shrub cover is expanding due to climate change and for the development of vegetation on terrain exposed by retreating ice.

Ground temperature variability on a glacier foreland, Storbreen, Jotunheimen, Norway

Two-years of ground temperatures (10 cm and 50 cm depths) from the foreland of Storbreen in the Jotunheimen Mountains of Norway demonstrate that seasonal and annual ground temperature differences induced by microtopographic position at a constant elevation are comparable to differences stemming from ∼ 100 m to ∼ 300 m in elevation. Between ∼ 1460 m a.s.l. and ∼ 1150 m a.s.l., mean annual lapse rates calculated for soil depths of 10 cm were≤0.8°C per100m beneath tundra, moraine crests, and moraine proximal base positions, each of which was calculated independently. Seasonal lapse rates were often larger,≥1.0°C per 100m in both summer and winter. The calculated ground temperature lapse rates compare favorably with those already reported in the literature for the region. Categorical data in the form of Thawed, Freeze-Thaw, Isothermal, and Frozen Days also showed considerable variability by elevation and microtopographic position. Variability in growing conditions was examined by calculating Thawing Degree Days and Growing Degree Days. These values sometimes, but not always, mimic ground temperature patterns. Although no wintertime field observations are available, the depth and duration of seasonal snow cover appears to be the primary source of variability.