Rising Summer Temperatures Research Articles

Contribution of snow and glacier melt to discharge for highly glacierised catchments in Norway

Abstract. Glacierised catchments show a discharge regime that is strongly influenced by snow and glacier meltwaters. In this study, we modelled the mass balance and discharge rates for three highly glacierised catchments (>50% glacier cover) in western Norway over the period 1961–2012. The spatial pattern of the catchments follows a gradient in climate continentality from west to east. The model input were gridded temperature and precipitation values from seNorge (http://senorge.no) which are available at daily resolution. The model accounted for accumulation of snow, transformation of snow to firn and ice, evaporation and melt. Calibration and validation were performed for each catchment based on measurements of seasonal glacier mass balances and daily discharge rates, as additional validation data served daily melt rates from sonic rangers located in the ablation zones of two of the glaciers. The discharge sources snowmelt, glacier melt and rain were analysed with respect to spatial variations and temporal evolution. Model simulations reveal an increase in the relative contribution from glacier melt to total discharge for the three catchments from less than 10% in the early 1990s to 15–30% in the late 2000s. The decline in precipitation by 10–20% in the same period was therefore overcompensated, resulting in an increase in annual discharge by 5–20%. Annual discharge sums and annual glacier melt are most strongly correlated with annual and winter precipitation at the most maritime glacier and, with increased climate continentality, variations in both glacier melt contribution and annual discharge are becoming more strongly correlated with variations in summer temperatures. Therefore, glaciers in more continental climates are especially vulnerable to decrease in both annual and summer discharge with continued rise in summer temperatures and subsequent decrease in glacier extent. This may lead to significant changes to the discharge regime, with increase during spring but decline later in the year, especially for catchments in less maritime climate conditions.

'Beast' 장미 꽃목굽음지의 생장, 화기 및 내생 호르몬 변화

The bent peduncle phenomenon (BPP) is known as a kind of physiological disorders found in cut rose plants, which causes the reduction of cut flower yields. As yet unknown mechanisms, however, it has not been easy to find solutions for BPP. To address this challenge, this study was conducted to investigate the characteristics of floral morphology, growth, and endogenous phytohormone level of BPP shoots in cut rose plants (Rosa hybrida L. 'Beast'). Morphological observation confirmed the fact that BPP was accompanied by the early formation and being phyllody of a specific sepal among five sepals, which gave rise to peduncle bending in the upper part of the phyllody with fasciation. Year-round BPP frequency in 'Beast' cultivar was in the range of 5 to 20% with seasonal change, increasing rapidly with an average temperature rise in summer. Except bent peduncle, the BPP shoots appeared to grow normally in terms of speed and size of floral development in comparison with normal. However, carbohydrate distribution to the floral part in BPP shoots was significantly reduced. The level of endogenous IAA (3-Indoleacetic acid) within the floral part in BPP shoots was highly maintained during floral development, in contrast to normal shoots. GA3 contents were not significantly different between normal and BPP shoots. This study indicates that BPP would be induced by a series of courses: abnormally early formation of a specific sepal relative to high temperature, being phyllody of the sepal with fasciation, and continuous supply of endogenous IAA by phyllody.

S084025 低炭素社会を目指した持続可能な都市エネルギーシステムに関する研究([S084-02]分散型エネルギーシステム(2))

With the great east Japan earthquake disaster, the electrical power supply-demand balance became tight in the summer. In this paper, we examined two countermeasures to alleviate severe situation of electricity supply and demand from short-term and long term viewpoints. One is estimation of an output decrement of thermal power generation by ambient air temperature rise in summer. The other is prediction of effects of large scale introduction of renewable energy to an electric power system. As the result, frequency change of the electric power system was calculated and the introductory limit of photovoltaics was predicted.

Elevation and volume changes of seven Dickson Land glaciers, Svalbard, 1960–1990–2009

Melting Svalbard glaciers have been recognized as an early indicator of climate change. Large parts of Svalbard remain insufficiently investigated, including Dickson Land, in the quasi-continental interior of Svalbard. In this study, elevation and volume changes of seven glaciers located in the Pyramiden region are assessed by analysing contour lines from 1960 topographic maps and photogrammetrically derived 1990 and 2009 digital elevation models. Mass loss was documented for all seven glaciers. In the period 1960-1990, their average elevation change rate was -0.49 m a-1, while in the more recent period, 1990-2009, it was more negative at 0.78 m a-1, caused by a significant equilibrium line altitude shift with post-1990 rise in summer temperatures. Large variation in elevation change rates between individual glaciers was found and is attributed mainly to aspect and hypsometry. This highlights the importance of choosing a representative sample when investigating mass balance of whole regions. Evidence of a rapid increase in thinning rates in the upper parts of the studied glaciers, linked to decreasing albedo in former accumulation zones, was also found.Keywords: Central Svalbard; Dickson Land; Pyramiden; glacier thinning; geometry changes; glacier volume(Published: 8 October 2013)Citation: Polar Research 2013, 32, 18400, http://dx.doi.org/10.3402/polar.v32i0.18400

Arizona Native Plants and the Urban Challenge

This paper explores how Arizona landscape architects have promoted the use of Sonoran native plants in Phoenix, Tucson, and surrounding desert cities and examines their strategies to create ecologically minded communities in challenging surroundings. In promoting native plants, landscape architects have not only created a vernacular landscape for Arizona’s cities, but have helped find solutions to rising summer temperatures and excessive use of borrowed water. In their planning and design for native plants, they have integrated native plants into the diverse functions of cities, both societal and ecological, creating multifunctional landscapes. While these endeavors have widely entrenched native plant design as part of major urban initiatives in Arizona’s desert cities, they have also revealed radical obstacles for native plant designs. Landscape architects have had to find a place for native plant systems amidst the diverse sets of needs of arid cities, from city-wide infrastructure systems to commercial interests and popular preferences, and in light of an overall energy balance within a desert region. This encounter marks yet another chapter in the history of landscape architects’ work with native plants.

Central West Antarctica among the most rapidly warming regions on Earth

There is clear evidence that the West Antarctic Ice Sheet is contributing to sea-level rise. In contrast, West Antarctic temperature changes in recent decades remain uncertain. West Antarctica has probably warmed since the 1950s, but there is disagreement regarding the magnitude, seasonality and spatial extent of this warming. This is primarily because long-term near-surface temperature observations are restricted to Byrd Station in central West Antarctica, a data set with substantial gaps. Here, we present a complete temperature record for Byrd Station, in which observations have been corrected, and gaps have been filled using global reanalysis data and spatial interpolation. The record reveals a linear increase in annual temperature between 1958 and 2010 by 2.4±1.2 °C, establishing central West Antarctica as one of the fastest-warming regions globally. We confirm previous reports of West Antarctic warming, in annual average and in austral spring and winter, but find substantially larger temperature increases. In contrast to previous studies, we report statistically significant warming during austral summer, particularly in December–January, the peak of the melting season. A continued rise in summer temperatures could lead to more frequent and extensive episodes of surface melting of the West Antarctic Ice Sheet. These results argue for a robust long-term meteorological observation network in the region. The West Antarctic Ice Sheet is contributing to sea-level rise, but temperature trends in the region have remained uncertain. A complete temperature record for Byrd Station in central West Antarctica, spanning from 1958 to 2010, establishes West Antarctica as one of the fastest-warming regions globally.

Variation of Maximum Tree Height and Annual Shoot Growth of Smith Fir at Various Elevations in the Sygera Mountains, Southeastern Tibetan Plateau

Little is known about tree height and height growth (as annual shoot elongation of the apical part of vertical stems) of coniferous trees growing at various altitudes on the Tibetan Plateau, which provides a high-elevation natural platform for assessing tree growth performance in relation to future climate change. We here investigated the variation of maximum tree height and annual height increment of Smith fir (Abies georgei var. smithii) in seven forest plots (30 m×40 m) along two altitudinal transects between 3,800 m and 4,200/4,390 m above sea level (a.s.l.) in the Sygera Mountains, southeastern Tibetan Plateau. Four plots were located on north-facing slopes and three plots on southeast-facing slopes. At each site, annual shoot growth was obtained by measuring the distance between successive terminal bud scars along the main stem of 25 trees that were between 2 and 4 m high. Maximum/mean tree height and mean annual height increment of Smith fir decreased with increasing altitude up to the tree line, indicative of a stress gradient (the dominant temperature gradient) along the altitudinal transect. Above-average mean minimum summer (particularly July) temperatures affected height increment positively, whereas precipitation had no significant effect on shoot growth. The time series of annual height increments of Smith fir can be used for the reconstruction of past climate on the southeastern Tibetan Plateau. In addition, it can be expected that the rising summer temperatures observed in the recent past and anticipated for the future will enhance Smith fir's growth throughout its altitudinal distribution range.

Palaeoecological evidence for the middle and late Holocene vegetation, climate and land use in the upper Don River basin (Russia)

New pollen and plant macrofossil data, backed by radiocarbon dates, from the Kulikovo battlefield area in the forest-steppe region of the Upper Don River basin (central part of European Russia) indicate that the area was covered by mosaic vegetation in the second half of the Holocene. Steppe communities dominated during the mid—late Atlantic (7.2–5.7 cal. kyr b.p.) and early Subatlantic (2.7–2.4 cal. kyr b.p.), while forest-steppe dominated during the Subboreal (2.7–5.7 cal. kyr b.p.), middle and late Subatlantic (2.4 cal. kyr b.p. – present). Climatic reconstructions based on these data show that landscape dynamics in the region were most probably driven by changes in effective moisture: an excess of precipitation over evaporation. Even small reductions in annual precipitation, accompanied by a rise in summer temperatures by 1–3°C above present values, were sufficient to increase the proportion of steppe communities within this landscape complex, and also probably resulted in higher frequencies of wildfires. Signals of anthropogenic disturbance of vegetation are clearly pronounced in the pollen and plant macrofossil records since the middle Atlantic. However, human-induced changes in the vegetation remain subtle until the medieval period.

Modelling potential distribution of the threatened tree species Juniperus oxycedrus: how to evaluate the predictions of different modelling approaches?

AbstractQuestions: How can predictions of potential species distribution derived from presence‐only data and different modelling algorithms be compared and evaluated? Where does suitable habitat for Juniperus oxycedrus exist within the study area and which bioclimatic variables prove to be most important in the prediction of J. oxycedrus potential distribution?Location: Central High Atlas, Morocco.Methods: Ecological niche factor analysis (ENFA), maximum entropy approach (MAXENT) and generalized linear models (GLM) were applied to either presence‐only data of J. oxycedrus (ENFA and MAXENT) or presence–absence data (GLM), using bioclimatic variables as predictors. Model accuracy of ENFA, MAXENT and GLM was assessed using their specific evaluation measures and prediction success by means of the minimal predicted area (MPA). Finally, the three maps of potential species distribution were intersected to investigate their consistency in the geographic distribution of predicted suitable habitat.Results: Species distribution models calculated by ENFA, MAXENT and GLM show good model quality according to their evaluation measures. However, calculation of MPA revealed considerable discrepancies in geographic distribution and spatial extent of areas predicted as suitable habitat for J. oxycedrus.Conclusion: Suitable habitat for J. oxycedrus is predicted using all applied modelling approaches in 8% of the study area (mostly the north‐western part). MAXENT gave the best results considering model accuracy and prediction success according to the MPA scores. Predictors representing maximum temperature and potential radiation were selected in all methods to explain species occurrences. This points to a possible shift of the species' potential distribution in cases of a rise in summer temperature due to climate change.

Assessing the results of scenarios of climate and land use changes on the hydrology of an Italian catchment: modelling study

AbstractHydrological models are recognized as valid scientific tools to study water quantity and quality and provide support for the integrated management and planning of water resources at different scales. In common with many catchments in the Mediterranean, the study catchment has many problems such as the increasing gap between water demand and supply, water quality deterioration, scarcity of available data, lack of measurements and specific information. The application of hydrological models to investigate hydrological processes in this type of catchments is of particular relevance for water planning strategies to address the possible impact of climate and land use changes on water resources.The distributed catchment scale model (DiCaSM) was selected to study the impact of climate and land use changes on the hydrological cycle and the water balance components in the Apulia region, southern Italy, specifically in the Candelaro catchment (1780 km2). The results obtained from this investigation proved the ability of DiCaSM to quantify the different components of the catchment water balance and to successfully simulate the stream flows. In addition, the model was run with the climate change scenarios for southern Italy, i.e. reduced winter rainfall by 5–10%, reduced summer rainfall by 15–20%, winter temperature rise by 1·25–1·5 °C and summer temperature rise by 1·5–1·75 °C. The results indicated that by 2050, groundwater recharge in the Candelaro catchment would decrease by 21–31% and stream flows by 16–23%. The model results also showed that the projected durum wheat yield up to 2050 is likely to decrease between 2·2% and 10·4% due to the future reduction in rainfall and increase in temperature.In the current study, the reliability of the DiCaSM was assessed when applied to the Candelaro catchment; those parameters that may cause uncertainty in model output were investigated using a generalized likelihood uncertainty estimation (GLUE) methodology. The results showed that DiCaSM provided a small level of uncertainty and subsequently, a higher confidence level. Copyright © 2010 John Wiley & Sons, Ltd.

Environmental change without climate change?

Environmental change without climate change?

Adaptation to Climate Change: A Framework for Analysis with Examples from the Netherlands

Climate change will have a considerable effect on the level of services provided by housing and infrastructure. In the coming decades interventions will be necessary to maintain these services at an adequate level. Such interventions can be incremental or radical, depending on the physical and societal context. This paper presents a framework for analysis of adaptation policies. The use of this framework is illustrated for sea level rise and the level of services provided by flood protection works in the Netherlands and for temperature rise in summer and the need for cooling in urban areas. Although the framework has already proved its value for the selected cases, further testing is recommended.

Spatial variability of recent glacier area changes in the Tien Shan Mountains, Central Asia, using Corona (~ 1970), Landsat (~ 2000), and ALOS (~ 2007) satellite data

Geographic variability of the recent changes of glacier coverage in the Tien Shan Mountains, Central Asia, is assessed using Corona KH-4B satellite photographs for 1968–1971, Landsat 7 ETM+data for 1999–2002, and ALOS/PRISM and AVNIR data for 2006–2008. The four mountain regions investigated (Pskem, Ili-Kungöy, At-Bashy, and SE-Fergana) cover several distributed glacierized areas in the Tien Shan Mountain system, a region that is affected by highly variable local precipitation regimes. Over the 30 years investigated between ~ 1970 and ~ 2000, glacier area decreased by 19% in the Pskem region, 12% in the Ili-Kungöy region, 12% in the At-Bashy region, and 9% in the SE-Fergana region. In the last 7 years (~ 2000 to ~ 2007), glacier area shrank by 5% in the Pskem region, 4% in the Ili-Kungöy region, 4% in the At-Bashy region, and 0% in the SE-Fergana region. Glacier behavior has varied markedly in these regions. The most dramatic glacier shrinkage has occurred in the outer ranges of the Tien Shan Mountains. Recent glacier area loss has resulted from rising summer temperatures. Regional differences of glacier-area changes related to local climate conditions, to the altitudinal distribution of glacier areas, and to the relative proportion of glaciers in different size classes. The observed accelerated glacier shrinkage is expected to have two impacts on the more populated outer ranges: 1) water shortages during summer and 2) increased threat from glacier hazards such as glacier lake outburst floods (GLOFs) and ice avalanches.

Landscape-and-climate dynamics and land use in Late Holocene forest-steppe ecotone of East European Plain (upper Don River Basin case study)

Results of lithological and palynological data of key sequences of the forest-steppe region in the Upper Don River basin, notably, the Kulikovo Battle-Field area, are presented. The obtained evidence shows the occurrence of open forest-steppe and steppe landscape in the Late Holocene. Climate reconstructions failed to demonstrate any drastic changes in the second half of the Holocene. However, even small reductions in annual precipitation, from 400 to 500 mm in the Atlantic, to 300–400 mm in the Subboreal period, accompanied by the rise of summer temperature, from 20–22 °C to 22–24 °C, respectively, were sufficient to cause landscape changes from the forest-steppe to typical steppe. The paper discusses various aspects of human impact on the landscape.

Diversity in environmental controls of flowering in Australian plants

In adapting their flowering to a particular season of the year, plants utilize a number of environmental inputs. Knowledge of these environmental controls of flowering is important for production in commercial horticulture. Such information is also relevant for assessing whether or not a species is threatened by global warming. Here, for five Australian plant species, we document ways in which the environment regulates their flowering. Spring flowering of Crowea exalata ‘Bindelong Compact’ reflects a response to increased daily light integral, these plants showing no hint of a true long day photoperiodic response. Higher temperatures not only cause earlier flowering of this Crowea cultivar but also depress flower production (5% loss per 1 °C increase). By contrast, another Crowea, ‘White Star’, flowers only if exposed to cool temperatures (15 °C) at the time of the increase in daily light integral. Thus, in commercial horticulture, synchronous and rapid flowering of Crowea will be possible by shifting plants from shade to high light conditions. In nature, light intensity will also have a major impact on flowering. By contrast, best flowering of Lechenaultia formosa in spring is a response to short photoperiods at high temperature while L. biloba prefers long days and has potentially spring to summer flowering. Whereas rising summer temperatures could have a deleterious effect on flowering of C. exalata, global warming may have little impact on L. formosa and L. biloba which flower more profusely in warmer conditions. Another spring flowering species, Verticordia chrysantha, responds both to short days and to exposure to cool temperatures so its survival could be threatened by global warming. For Calytrix fraseri its late summer flowering in nature is explained by its requirement for an exposure to long days. When combined with information previously published for Australian plants, it is clear that there are no simple generalizations to explain why a plant species flowers when it does.

Near-Synchronous Interhemispheric Termination of the Last Glacial Maximum in Mid-Latitudes

Isotopic records from polar ice cores imply globally asynchronous warming at the end of the last glaciation. However, 10Be exposure dates show that large-scale retreat of mid-latitude Last Glacial Maximum glaciers commenced at about the same time in both hemispheres. The timing of retreat is consistent with the onset of temperature and atmospheric CO2 increases in Antarctic ice cores. We suggest that a global trend of rising summer temperatures at the end of the Last Glacial Maximum was obscured in North Atlantic regions by hypercold winters associated with unusually extensive winter sea ice.

Monitoring the glacier changes in the Muztag Ata and Konggur mountains, east Pamirs, based on Chinese Glacier Inventory and recent satellite imagery

AbstractGlaciers in the Muztag Ata and Konggur mountains of the eastern Pamir plateau, northwestern China, have been monitored by applying aerial photo stereo models (1962/66) and Landsat TM (1990) and ETM+ (1999) images, all of which have been compared in order to detect areal and frontal changes through the past four decades. The mean frontal retreat of glaciers in the Muztag Ata and Konggur mountains increased from 6.0 ma−1 between 1962/66 and 1990 to 11.2ma−1 between 1990 and 1999, with an overall glacier length reduction of 9.9% for the whole study period. The glacier area has decreased by 7.9%, mainly due to changes observed in the most recent period (1990–99), when the annual area loss almost tripled to 1.01 km2 a−1. Based on meteorological data from Taxkogan station since 1957, we conclude that climate change, particularly the rise in summer temperature after 1994, is the main forcing factor in glacier shrinkage.

Seasonal and regional temperature changes in China over the 50 year period 1951–2000

Statistical tests were used to detect the variations of winter (December to February), summer (June to August), and annual mean temperatures of 160 representative stations in China during the period from 1951 to 2000. Changes of temperature in the observed time series that exceed the confidence level of 0.01 were classified as significant temperature rises or drops. The stations with significant temperature rises were classified into several temperature rise types, by the use of a clustering method. A search was made for sudden, or abrupt, temperature changes at each of the 160 stations. Possible reasons for the observed temperature variations are discussed. The statistical analysis reveals that for the 160 stations, significant rises occur in 53.1% of their annual mean temperatures, 51.9% of their winter temperatures, and 13.8% of their summer temperatures. Temperature rises increase with latitude. In contrast, significant drops occur in annual mean temperatures at 1 station, winter temperatures at 3 stations, and summer temperatures at 5 stations. Approximately 50% of stations with significant temperature variations are in the form of abrupt changes. The abrupt temperature changes all occurred in the 1970s, most often in 1979 and 1980. The abrupt changes are shown to be related to the subtropical high in South China Sea. The temperature rises in winter are shown to be linked to the presence of an anomalously strong zonal circulation in Eurasia, and a weak polar vortex, since the 1980s. The summer temperature rise in South China also has a link with the increase in size and intensity of the subtropical high, over the same period. Some of the station temperature drops in summer were related to a weaker summer monsoon. The annual mean temperature rise at 71.8% of the stations was influenced mainly by their winter temperature rises. For 8.2% of the stations, the annual mean temperature rise was connected to their summer temperature rise, and for 12.9% of the stations it was related to both the summer and winter temperature rises.

SARS--beginning to understand a new virus.

The 114-day epidemic of the severe acute respiratory syndrome (SARS) swept 29 countries, affected a reported 8,098 people, left 774 patients dead and almost paralyzed the Asian economy. Aggressive quarantine measures, possibly aided by rising summer temperatures, successfully terminated the first eruption of SARS and provided at least a temporal break, which allows us to consolidate what we have learned so far and plan for the future. Here, we review the genomics of the SARS coronavirus (SARS-CoV), its phylogeny, antigenic structure, immune response and potential therapeutic interventions should the SARS epidemic flare up again.

Late Glacial and Holocene environmental history of the Pirin Mountains (SW Bulgaria): a paleolimnological study of Lake Dalgoto (2310 m)

Diatoms, Cladocera, and chironomids preserved in the sediments of Lake Dalgoto were studied to reconstruct the history of the lake ecosystem in the context of the vegetation history as represented by the pollen stratigraphy. Younger Dryas silty sediments at the base of the core are characterized by low diversity of aquatic organisms. The transition to the Holocene is indicated by a sharp change from silt to clay-gyttja. The migration and expansion of trees at lower elevations between 10200 and 8500 14C-yr BP, along with higher diversities and concentrations of aquatic organisms and the decreased proportion of north-alpine diatoms, point to rapidly rising summer temperatures. After 6500 14C-yr BP the expansion of Pinus mugo in the catchment coincides with signs of natural eutrophication as recorded by an increase of planktonic diatoms. In the late Holocene (4000–0 14C-yr BP) Pinus peuce and Abies are reduced and Picea expands. Cereal grains and disturbance indicators suggest late-Holocene human modification of the vegetation.