Annual Temperature Difference Research Articles

Distributions of carbon and nitrogen isotopes in Scotland's topsoil: a national‐scale study

SummaryThe land use and climate of Scotland are currently undergoing change. Concentrations of Natural abundance stable isotopes in ecosystems have been used extensively to help to understand a wide range of processes and functions. In the current study topsoil was collected from the intercepts of a 20‐km grid across the whole of Scotland (183 points), which encompass large differences in mean annual temperature (MAT,3.1–9.1°C), mean annual precipitation (MAP, 588–3470 mm) and land use (from arable land through grassland and woodland to less fertile moorlands and bogs). At each sampling point the natural abundance δ13C and δ15N values were measured. This paper describes for the first time the spatial distribution of these isotopes in the topsoil of Scotland. We applied linear modelling to assess the extent to which land use and climate can control the observed distributions. The more enriched topsoil δ13C values occurred in the northern and western regions of Scotland. Topsoil δ13C values were tightly constrained about the mean, and possibly because of this we were able to explain only 23.6% of the variance even after considering the potential effects of a wide range of abiotic factors and land uses. Precipitation and land use explained the greatest variance in topsoil δ13C, but individually this was only 10.4 and 9.9%, respectively. Topsoil δ15N values showed a more complex spatial arrangement. The main areas of the more enriched δ15N values were in the northern isles, along or near the coast on the eastern side of the country and in some areas of the western mainland. For topsoil δ15N, all explanatory variables together explained 55.7% of the variance, with land use alone explaining 45.4%. Soil under arable land and improved grassland, the more fertile sites, had the most enriched δ15N values, whereas woodland and bogs had the most depleted values. A positive relationship between topsoil δ15N and potential rate of nitrification suggested that this was due, at least in part, to greater losses of nitrate under arable land and improved grassland.

Fault detection in district heating substations

Current temperature levels in European district heating networks are still too high with respect to future conditions as customer heat demands decrease and new possible heat source options emerge. A considerable reduction of temperature levels can be accomplished by eliminating current faults in substations and customer heating systems. These faults do not receive proper attention today, because neither substations nor customer heating systems are centrally supervised. The focus of this paper has been to identify these faults by annual series of hourly meter readings obtained from automatic meter reading systems at 135 substations in two Swedish district heating systems. Based on threshold methods, various faults were identified in 74% of the substations. The identified faults were divided into three different fault groups: Unsuitable heat load pattern, low average annual temperature difference, and poor substation control. The most important conclusion from this early study of big data volumes is that automatic meter reading systems can provide proactive fault detection by continuous commissioning of district heating substations in the future. A complete reduction of current faults corresponds to approximately half the required reduction of the current temperature levels in the effort toward future low-temperature district heating networks.

Comparison of in situ and satellite sea surface-temperature data from South Australia and Tasmania: how reliable are satellite data as a proxy for coastal temperatures in temperate southern Australia?

Satellite sea-surface temperature (SST) is widely used for biological modelling and ecological studies, assuming it represents subsurface in situ temperature (IST). We tested this assumption at 32 coastal sites in southern Australia, spanning a wide geographic range. Annual IST regimes are described and were demonstrated to be highly correlated with SST. Mean annual daily temperature differences between SST and IST (DTD) were generally small, varying spatially and seasonally (range 0–1°C). No correlation between DTDs and a range of site attributes was found, indicating the importance of site-specific factors. Seasonal DTDs were not geographically consistent, being higher in South Australia during the summer (mean 1.4°C) than in Tasmania (mean 0.5°C). Generally, small annual mean DTDs justify using SST for broad-scale ecological and climate-change studies, although considerable DTDs at some sites suggest that using SST at smaller spatial and temporal scales is unlikely to be appropriate. In addition, SST data lack information on daily temperature fluctuation that may be biologically relevant. Excepting South Australia, where spatially consistent summer DTDs would allow a correction factor, this site-specific variation is hard to correct. In spite of this, studies that rely on SST should consider the implications of such variation on the level of certainty associated with temperature-based predictions.

Are seed mass and seedling size and shape related to altitude? Evidence in Gymnocalycium monvillei (Cactaceae)

Several studies reported a negative relationship between altitude and seed mass. In cactus species, seed mass has been also related to seedling morphology (size and shape). Here we studied Gymnocalycium monvillei (Lem.) Pfeiff. ex Britton & Rose, a cactus species with a wide altitudinal distribution, with the main aim of analyzing how altitude affects seed mass and seedling size (height and width) and shape (globose or columnar). We collected seeds from five sites along the entire altitudinal distribution of the species in the Córdoba Mountains (sites were located between 878 and 2230 m a.s.l.), encompassing a marked climatic gradient (6 °C of mean annual temperature difference between the extreme sites). Seed mass and seedling traits were measured in the laboratory. Seedling height increased with altitude, whereas seed mass was not related to this parameter. Seedlings became more globose (reduced surface/volume ratio) with decreasing altitude. Variation in seedling shape along the altitudinal gradient may be related to the contrasting climatic conditions to which seedlings are exposed, and could account for the wide altitudinal distribution of G. monvillei. Our results highlight the importance of seedling traits in the species’ response to climatic change.

Urban warming in villages

Abstract. Long term meteorological records (> 100 years) from stations associated with villages are generally classified as rural and assumed to have no urban influence. Using networks installed in two European villages, the local and microclimatic variations around two of these rural-village sites are examined. An annual average temperature difference ($\\Delta{T}$) of 0.6 and 0.4 K was observed between the built-up village area and the current meteorological station in Geisenheim (Germany) and Haparanda (Sweden), respectively. Considerably larger values were recorded for the minimum temperatures and during summer. The spatial variations in temperature within the villages are of the same order as recorded over the past 100+ years in these villages (0.06 to 0.17 K/10 years). This suggests that the potential biases in the long records of rural-villages also warrant careful consideration like those of the more commonly studied large urban areas effects.

Geographic body size variation in the periodical cicadas Magicicada: implications for life cycle divergence and local adaptation.

Seven species in three species groups (Decim, Cassini and Decula) of periodical cicadas (Magicicada) occupy a wide latitudinal range in the eastern United States. To clarify how adult body size, a key trait affecting fitness, varies geographically with climate conditions and life cycle, we analysed the relationships of population mean head width to geographic variables (latitude, longitude, altitude), habitat annual mean temperature (AMT), life cycle and species differences. Within species, body size was larger in females than males and decreased with increasing latitude (and decreasing habitat AMT), following the converse Bergmann's rule. For the pair of recently diverged 13- and 17-year species in each group, 13-year cicadas were equal in size or slightly smaller on average than their 17-year counterparts despite their shorter developmental time. This fact suggests that, under the same climatic conditions, 17-year cicadas have lowered growth rates compared to their 13-years counterparts, allowing 13-year cicadas with faster growth rates to achieve body sizes equivalent to those of their 17-year counterparts at the same locations. However, in the Decim group, which includes two 13-year species, the more southerly, anciently diverged 13-year species (Magicicada tredecim) was characterized by a larger body size than the other, more northerly 13- and 17-year species, suggesting that local adaptation in warmer habitats may ultimately lead to evolution of larger body sizes. Our results demonstrate how geographic clines in body size may be maintained in sister species possessing different life cycles.

Effect of light intensities on the photosynthetic characteristics of Abies holophylla seedlings from different provenances

The photosynthetic characteristics of Abies holophylla seedlings from six provenances under four artificial light intensities in a greenhouse (full light, 75.08%, 55.42%, and 30.38% of full light) were studied to explore the underlying genetic differences in foliar photosynthesis. Varying light intensities significantly affected the foliar photosynthetic parameters of A. holophylla seedlings from six provenances. As the light intensity dropped, the foliar CO2 assimilation capacity of A. holophylla seedlings sharply decreased, and the foliar light utilization capacity significantly increased. Analysis of genetic variation showed highly significant differences in terms of CO2 assimilation capacity, light utilization capacity, and respiration depletion of A. holophylla seedlings among different provenances under different light intensities. The variations were mainly controlled by the genetic factors of the provenance itself. The obtained results revealed that different sensitivities of A. holophylla seedlings from different provenances in response to changed light intensities elicited significant differences in foliar photosynthesis among different provenances. The relationships between sensitivities and annual temperature difference, mean temperature in January, and mean annual evaporation of provenance were found to be the most closely related, which indicated that temperature range and effective precipitation of provenance were the main factors that affected photosynthetic plasticity of A. holophylla seedlings.

Life history differences ofPsilotreta locumtenens(Trichoptera: Odontoceridae) in two reaches of a mountain stream in Korea

The life history traits of the caddisfly, Psilotreta locumtenens Botosaneanu (Odontoceridae), were studied in two stream reaches with different thermal ranges (main and branch streams) of the Gapyeong Stream, a typical mountain stream located in the central Korean Peninsula. Psilotreta locumtenens larvae were quantitatively sampled monthly from November 2008 to July 2010, and biweekly during the emergence period (late April to early July), using a Surber sampler (30 × 30 cm). Adults were quantitatively sampled with a sweep net. Larval density in the main stream (324.21 ± 38.59 m−2) was higher than that in the branch stream (60.48 ± 10.86 m−2). The larvae hatched in the early summer and overwintered as 5th and 3rd instars in the main and branch streams, respectively. The emergence peak at the main stream was approximately 2 weeks earlier. The sex ratio at both sites was approximately 0.3. The life history in both streams was univoltine. Secondary production in the main stream was much higher than in the branch stream, owing to high larval densities, and the P/B ratios at the two sites were similar. This study demonstrated remarkable differences in larval growth patterns and emergence peaks in P. locumtenens between the two stream reaches due to differences in accumulated degree days (230.30 DD) and other phenological cues such as daily mean threshold water temperature (9°C) during the ascending phase, despite their relatively small mean annual water temperature difference of 0.58°C.

Achieving low return temperatures from district heating substations

District heating systems contribute with low primary energy supply in the energy system by providing heat from heat assets like combined heat and power, waste incineration, geothermal heat, wood waste, and industrial excess heat. These heat assets would otherwise be wasted or not used. Still, there are several reasons to use these assets as efficiently as possible, i.e., ability to compete, further reduced use of primary energy resources, and less environmental impact. Low supply and return temperatures in the distribution networks are important operational factors for obtaining an efficient district heating system. In order to achieve low return temperatures, customer substations and secondary heating systems must perform without temperature faults. In future fourth generation district heating systems, lower distribution temperatures will be required. To be able to have well-performing substations and customer secondary systems, continuous commissioning will be necessary to be able to detect temperature faults without any delays. It is also of great importance to be able to have quality control of eliminated faults. Automatic meter reading systems, recently introduced into district heating systems, have paved the way for developing new methods to be used in continuous commissioning of substations. This paper presents a novel method using the temperature difference signature for temperature difference fault detection and quality assurance of eliminated faults. Annual hourly datasets from 140 substations have been analysed for temperature difference faults. From these 140 substations, 14 were identified with temperature difference appearing or eliminated during the analysed year. Nine appeared during the year, indicating an annual temperature difference fault frequency of more than 6%.

Active layer thermal regime at different vegetation covers at Lions Rump, King George Island, Maritime Antarctica

Climate change impacts the biotic and abiotic components of polar ecosystems, affecting the stability of permafrost, active layer thickness, vegetation, and soil. This paper describes the active layer thermal regimes of two adjacent shallow boreholes, under the same soil but with two different vegetations. The study is location in Lions Rump, at King George Island, Maritime Antarctic, one of the most sensitive regions to climate change, located near the climatic limit of Antarctic permafrost. Both sites are a Turbic Cambic Cryosol formed on andesitic basalt, one under moss vegetation (Andreaea gainii, at 85ma.s.l.) and another under lichen (Usnea sp., at 86ma.s.l.), located 10m apart. Ground temperature at same depths (10, 30 and 80cm), water content at 80cm depth and air temperature were recorded hourly between March 2009 and February 2011. The two sites showed significant differences in mean annual ground temperature for all depths. The lichen site showed a higher soil temperature amplitude compared to the moss site, with ground surface (10cm) showing the highest daily temperature in January 2011 (7.3°C) and the lowest daily temperature in August (−16.5°C). The soil temperature at the lichen site closely followed the air temperature trend. The moss site showed a higher water content at the bottommost layer, consistent with the water-saturated, low landscape position. The observed thermal buffering effect under mosses is primarily associated with higher moisture onsite, but a longer duration of the snowpack (not monitored) may also have influenced the results. Active layer thickness was approximately 150cm at low-lying moss site, and 120cm at well-drained lichen site. This allows to classify these soils as Cryosols (WRB) or Gelisols (Soil Taxonomy), with evident turbic features.

Response of surface air temperature to small-scale land clearing across latitudes

Climate models simulating continental scale deforestation suggest a warming effect of land clearing on the surface air temperature in the tropical zone and a cooling effect in the boreal zone due to different control of biogeochemical and biophysical processes. Ongoing land-use/cover changes mostly occur at local scales (hectares), and it is not clear whether the local-scale deforestation will generate temperature patterns consistent with the climate model results. Here we paired 40 and 12 flux sites with nearby weather stations in North and South America and in Eastern Asia, respectively, and quantified the temperature difference between these paired sites. Our goal was to investigate the response of the surface air temperature to local-scale (hectares) land clearing across latitudes using the surface weather stations as proxies for localized land clearing. The results show that north of 10°N, the annual mean temperature difference (open land minus forest) decreases with increasing latitude, but the temperature difference shrinks with latitude at a faster rate in the Americas [−0.079 (±0.010) °C per degree] than in Asia [−0.046 (±0.011) °C per degree]. Regression of the combined data suggests a transitional latitude of about 35.5°N that demarks deforestation warming to the south and cooling to the north. The warming in latitudes south of 35°N is associated with increase in the daily maximum temperature, with little change in the daily minimum temperature while the reverse is true in the boreal latitudes.

Comparative Study on Crack and Factor of Continuously Reinforced Concrete Pavement in the Tunnel and Outside

Punchout is the main destruction of continuously reinforced concrete pavement, which is closely related to concrete cracking, the form and distribution pattern of pavement crack. Temperature and humidity are important impact factors of concrete pavement cracking. Base on the analysis of temperature and humidity inside and outside the tunnel, this paper studies the influence of temperature and humidity on the continuously reinforced concrete pavement cracking conditions of the test-road, and the application of continuously reinforced concrete pavement in the tunnel and outside by investigating the crack development. It is found that the daily temperature difference is 2°C in the tunnel, the annual temperature difference and humidity are 8.9°C and 75 ∼ 85%, respectively. Temperature during the construction and curing temperature and humidity of continuously reinforced concrete pavement is of great influence on the crack occurrence. Cracks outside the tunnel occur more and are with concentrated distribution in the early stage. Crack distribution in the tunnel is more reasonable. After eight months including a winter, the crack number increased significantly outside, while the spacing was wider and the width was smaller in the tunnel. Results show that appropriate temperature and humidity can guarantee a cement road application, continuously reinforced concrete pavement crack form is more reasonable, performance in the crack width is small, the spacing is big, which reduces the possibility of punchout and spalling.

Tundra ecosystems observed to be CO2sources due to differential amplification of the carbon cycle

Are tundra ecosystems currently a carbon source or sink? What is the future trajectory of tundra carbon fluxes in response to climate change? These questions are of global importance because of the vast quantities of organic carbon stored in permafrost soils. In this meta-analysis, we compile 40years of CO2 flux observations from 54 studies spanning 32 sites across northern high latitudes. Using time-series analysis, we investigated if seasonal or annual CO2 fluxes have changed over time, and whether spatial differences in mean annual temperature could help explain temporal changes in CO2 flux. Growing season net CO2 uptake has definitely increased since the 1990s; the data also suggest (albeit less definitively) an increase in winter CO2 emissions, especially in the last decade. In spite of the uncertainty in the winter trend, we estimate that tundra sites were annual CO2 sources from the mid-1980s until the 2000s, and data from the last 7years show that tundra continue to emit CO2 annually. CO2 emissions exceed CO2 uptake across the range of temperatures that occur in the tundra biome. Taken together, these data suggest that despite increases in growing season uptake, tundra ecosystems are currently CO2 sources on an annual basis.

Using genetic variation to infer associations with climate in the common frog,Rana temporaria

Recent and historical species' associations with climate can be inferred using molecular markers. This knowledge of population and species-level responses to climatic variables can then be used to predict the potential consequences of ongoing climate change. The aim of this study was to predict responses of Rana temporaria to environmental change in Scotland by inferring historical and contemporary patterns of gene flow in relation to current variation in local thermal conditions. We first inferred colonization patterns within Europe following the last glacial maximum by combining new and previously published mitochondrial DNA sequences. We found that sequences from our Scottish samples were identical to (92%), or clustered with, the common haplotype previously identified from Western Europe. This clade showed very low mitochondrial variation, which did not allow inference of historical colonization routes but did allow interpretation of patterns of current fine-scale population structure without consideration of confounding historical variation. Second, we assessed fine-scale microsatellite-based patterns of genetic variation in relation to current altitudinal temperature gradients. No population structure was found within altitudinal gradients (average FST=0.02), despite a mean annual temperature difference of 4.5 °C between low- and high-altitude sites. Levels of genetic diversity were considerable and did not vary between sites. The panmictic population structure observed, even along temperature gradients, is a potentially positive sign for R. temporaria persistence in Scotland in the face of a changing climate. This study demonstrates that within taxonomic groups, thought to be at high risk from environmental change, levels of vulnerability can vary, even within species.

Rock damage and regolith transport by frost: an example of climate modulation of the geomorphology of the critical zone

ABSTRACTIn this article we craft process‐specific algorithms that capture climate control of hillslope evolution in order to elucidate the legacy of past climate on present critical zone architecture and topography. Models of hillslope evolution traditionally comprise rock detachment into the mobile layer, mobile regolith transport, and a channel incision or aggradation boundary condition. We extend this system into the deep critical zone by considering a weathering damage zone below the mobile regolith in which rock strength is diminished; the degree of damage conditions the rate of mobile regolith production. We first discuss generic damage profiles in which appropriate length and damage scales govern profile shapes, and examine their dependence upon exhumation rate. We then introduce climate control through the example of rock damage by frost‐generated crack growth. We augment existing frost cracking models by incorporating damage rate limitations for long transport distances for water to the freezing front. Finally we link the frost cracking damage model, a mobile regolith production rule in which rock entrainment is conditioned by the damage state of the rock, and a frost creep transport model, to examine the evolution of an interfluve under oscillating climate. Aspect‐related differences in mean annual surface temperatures result in differences in bedrock damage rate and mobile regolith transport efficiency, which in turn lead to asymmetries in critical zone architecture and hillslope form (divide migration). In a quasi‐steady state hillslope, the lowering rate is uniform, and the damage profile is better developed on north‐facing slopes where the frost damage process is most intense. Because the residence times of mobile regolith and weathered bedrock in such landscapes are on the order of 10 to 100 ka, climate cycles over similar timescales result in modulation of transport and damage efficiencies. These lead to temporal variation in mobile regolith thickness, and to corresponding changes in sediment delivery to bounding streams. Copyright © 2012 John Wiley & Sons, Ltd.

A 250 ka oxygen isotope record from diatoms at Lake El'gygytgyn, far east Russian Arctic

Abstract. In 2003 sediment core Lz1024 was drilled at Lake El'gygytgyn, far east Russian Arctic, in an area of the Northern Hemisphere which has not been glaciated for the last 3.6 Ma. Biogenic silica was used for analysing the oxygen isotope composition (δ18Odiatom) in the upper 13 m long section dating back about 250 ka with samples dominated by one taxa in the <10 μm fraction (Cyclotella ocellata). Downcore variations in δ18O values show that glacial-interglacial cycles are present throughout the core and δ18Odiatom-values are mainly controlled by δ18Oprecipitation. Changes reflect the Holocene Thermal Maximum, the Last Glacial Maximum (LGM) and the interglacial periods corresponding to MIS 5.5 and MIS 7 with a peak-to-peak amplitude between LGM and MIS 5.5 of Δ18O = 5.3‰. This corresponds to a mean annual air temperature difference of about 9 °C. Our record is the first continuous δ18Odiatom record from an Arctic lake sediment core directly responding to precipitation and dating back more than 250 ka and correlates well with the stacked marine δ18O LR04 (r = 0.58) and δD EPICA Dome-C record (r = 0.69). With δ18O results indicating strong links to both marine and ice-core records, records from Lake El'gygytgyn can be used to further investigate the sensitivity of the Arctic climate to both past and future global climatic changes.

Effect of altitude and latitude on surface air temperature across the Qinghai-Tibet Plateau

The correlation between mean surface air temperature and altitude is analyzed in this paper based on the annual and monthly mean surface air temperature data from 106 weather stations over the period 1961–2003 across the Qinghai-Tibet Plateau. The results show that temperature variations not only depend on altitude but also latitude, and there is a gradual decrease in temperature with the increasing altitude and latitude. The overall trend for the vertical temperature lapse rate for the whole plateau is approximately linear. Three methods, namely multivariate composite analysis, simple correlation and traditional stepwise regression, were applied to analyze these three correlations. The results assessed with the first method are well matched to those with the latter two methods. The apparent mean annual near-surface lapse rate is −4.8 °C /km and the latitudinal effect is −0.87 °C /olatitude. In summer, the altitude influences the temperature variations more significantly with a July lapse rate of -4.3°C /km and the effect of latitude is only −0.28°C /olatitude. In winter, the reverse happens. The temperature decrease is mainly due to the increase in latitude. The mean January lapse rate is −5.0°C /km, while the effect of latitude is −1.51°C /olatitude. Comparative analysis for pairs of adjacent stations shows that at a small spatial scale the difference in altitude is the dominant factor affecting differences in mean annual near-surface air temperature, aided to some extent by differences of latitude. In contrast, the lapse rate in a small area is greater than the overall mean value for the Qinghai-Tibet Plateau (5 to 13°C /km). An increasing trend has been detected for the surface lapse rate with increases in altitude. The temperature difference has obvious seasonal variations, and the trends for the southern group of stations (south of 33° latitude) and for the more northerly group are opposite, mainly because of the differences in seasonal variation at low altitudes. For yearly changes, the temperature for high-altitude stations occurs earlier clearly. Temperature datasets at high altitude stations are well-correlated, and those in Nanjing were lagged for 1 year but less for contemporaneous correlations. The slope of linear trendline of temperature change for available years is clearly related to altitude, and the amplitude of temperature variation is enlarged by high altitude. The change effect in near-surface lapse rate at the varying altitude is approximately 1.0°C /km on the rate of warming over a hundred-year period.

Basic density of radiata pine in New Zealand: genetic and environmental factors

Wood basic density is among the selection criteria for many fast-grown tree species, including Pinus radiata D. Don in New Zealand. Basic density was assessed in 23,330 stem cores from 18 trials to study the heritability, the relevance of environmental effects and the magnitude of genotype-by-environment (GxE) interaction. Site differences in annual average temperature dominated variability in this dataset, with lower latitude and altitude (i.e. warmer) sites displaying higher average density. Between highest- and lowest-density sites there was an 18% difference (302.7 vs. 358.4 kg m − 3) for the linear mean for cores of rings 1–5 and a 39% difference (329.7 vs. 459.1 kg m − 3) for the linear mean of rings 6–10. The estimated heritabilities fluctuated between 0.28 and 0.94 (mean, 0.6); however, basic density displayed little within-site variability (phenotypic coefficient of variation, <8%). Bivariate analyses were used to estimate between-site genetic correlations as an indication of GxE interaction. Only 57 out of the 153 pairs of trials contained enough information to estimate the between-site genetic correlations and, out of those, 15 estimates were not statistically significant. Moderate to high (0.46–0.96) significant genetic correlation estimates indicated that there was little interaction for basic density, suggesting no need to modify the breeding strategy to account for differential performance in this trait. Poor connectedness between trials could be depressing estimates of genetic correlations. This situation should be considered when designing genetic testing schemes, particularly when purposely inducing imbalance as in rolling front strategies.

アメダス資料による都市 (県庁所在地) とその周辺市町村の気温差年平均の分析

アメダス資料による都市 (県庁所在地) とその周辺市町村の気温差年平均の分析

Nationwide Desert Highway Assessment: A Case Study in China

The natural environment affects the construction of desert highways. Conversely, highway construction affects the natural environment and puts the ecological environment at a disadvantage. To satisfy the variety and hierarchy of desert highway construction and discover the spatio-temporal distribution of the natural environment and its effect on highway construction engineering, an assessment of the natural regional divisions of desert highways in China is carried out for the first time. Based on the general principles and method for the natural region division, the principles, method and index system for desert highway assessment is put forward by combining the desert highway construction features and the azonal differentiation law. The index system combines the dominant indicator and four auxiliary indicators. The dominant indicator is defined by the desert’s comprehensive state index and the auxiliary indicators include the sand dune height, the blown sand strength, the vegetation coverage ratio and the annual average temperature difference. First the region is divided according to the dominant indicator. Then the region boundaries are amended according to the four auxiliary indicators. Finally the natural region division map for desert highway assessment is presented. The Chinese desert highways can be divided into three sections: the east medium effect region, the middle medium-severe effect region, and the west slight-medium effect region. The natural region division map effectively paves the way for the route planning, design, construction, maintenance and ongoing management of desert highways, and further helps environmental protection.