Warm Index Research Articles

Recent trends in daily temperature extremes over northeastern China (1960–2011)

Based on long-term, high-quality, and homogenous daily maximum and minimum temperature of 70 meteorological stations spanning the period from 1960 to 2011, the spatial and temporal characteristics of extreme temperature events in northeastern China have been investigated. A total of 14 indices are used to assess changes in extreme temperature distributions. All the temperature-based indices show patterns consistent with a general warming trend. The regional occurrence of the increase in warm nights (TN90p: 2.17 days/decade) and warm days (TX90p: 0.97 days/decade), and decrease in cool nights (TN10p: −1.80 days/decade) and cool days (TXx: −0.86 days/decade) was detected in the past 52 years. Moreover, the trend magnitudes in cold/warm nights are larger than those in cold/warm days, which indicate that trends in minimum temperature extremes are more rapid than trends in maximum temperature extremes, consistent with a long-term decrease in DTR. The other indices, including TNn, TNx, SU25, TR20, FD0, ID0, GSL, and DTR, show statistically significant changes except for Maximum and minimum values of maximum daily temperatures (TXx and TXn) which have statistically insignificant slopes at individual stations and in regional mean trend. For the majority of stations, significant increases are detected for heat related extremes such as summer days and tropical nights (SU25 and TR20) as well as for maximum and minimum values of minimum daily temperatures (TNn and TNx); With the exception of diurnal temperature range (DTR) and maximum daily maximum temperature (TXx), the other indices strongly correlate with annual mean temperature. In addition, there are high correlations among warm indices and among cold ones, respectively.

The impact of heat waves on daily mortality in Belgrade (Serbia) during summer

In this paper, we are dealing with two extreme events in temperature and population – heat wave and mortality. Our aim is to assess the relation between high temperatures and daily mortality counts during the summer months in the period 2000–2010 in Belgrade (Serbia). In order to establish this connection, we used Poisson regression and two different measures of heat wave: Warm Spell Duration Index (WSDI) and apparent temperature (Tapp). As mean daily temperature increases over 90th, 95th and 99th percentiles, average number of deaths increases for 15.3% (p < .01), 22.4% (p < .05) and 32.0% (insignificant for p < .1). We tested three different thresholds (90th, 95th, 99th) for WSDI and Tapp in order to separate the hottest heat-wave episodes. On average, mortality is higher than expected for 13.4%, 16.7% and 28.3% (90th, 95th and 99th percentiles for WSDI) and 16.1%, 17.3% and 32.5% (90th, 95th and 99th percentiles for Tapp). Estimated mortality excess with heat-wave indices is in accordance with regression output, meaning that WSDI and Tapp are good tools for heat-wave identification. During the most severe episode in July 2007, absolute temperature maximum (43.6°C) and daily maximum mortality counts (94 dead) were recorded in the same day (24 July 2007).

Separation of Sulfur Hexafluoride from a Nitrogen/Sulfur Hexafluoride Mixture Using a Polymer Hollow Fiber Membrane

Sulfur hexafluoride (SF6) has been evaluated by the Intergovernmental Panel on Climate Change (IPCC) as the substance with the highest global warming index. Because of its superior insulating and arc clearing capacities, it is commonly used as an insulator in electrical machines. SF6 waste products form in the process of storing, maintaining, and repairing the machines. SF6 emitted into the atmosphere remains for 3,200 years, causing global warming. Release into the mesosphere leads to photolysis and creation of highly toxic and corrosive by-products. A review of the literature related to the retrieval and separation of SF6 using a separating membrane indicates that research on the permeability of the separating membrane material is lacking. Additionally, research on the concentrations of the SF6 waste products and the separation/retrieval with operating conditions with optimal energy efficiency is only in the initial stages. Therefore, this research assessed the permeability of commercialized separation membranes polysulfone (PSf), polycarbonate (PC), and polyimide (PI) using the gases SF6 and N2. Using an SF6/N2 mixture with the same concentration as the SF6 waste products, we studied the separation and retrieval capacities of PSf, PC, and PI separation membranes under varying operating conditions. The permeability tests showed that the selective permeability of N2/SF6 is highest for the PI membrane and lowest for the PC membrane. When the concentrations of SF6 retrieved from the mixture separation process were compared, the PC membrane was found to be the highest, with 95.6 % at 0.5 MPa. The retrieval percentage of SF6 was highest for PSf, with 97.8 % at an operating pressure of 0.3 MPa and a waste production of 150 cm3/min. The retrieval rates and retrieval failure rates have an inverse relationship. In total, 99 % of the supply of SF6 was identified via the retrieval rates and retrieval failure rates, so it could be confirmed that the separation of the SF6/N2 mixture using a macromolecular hollow fiber separation membrane works properly.

Changes in temperature extremes in the Yangtze River Basin, 1962–2011

Based on daily maximum and minimum temperature observed by the China Meteorological Administration at 115 meteorological stations in the Yangtze River Basin from 1962 to 2011, the methods of linear regression, principal component analysis and correlation analysis are employed to investigate the temporal variability and spatial distribution of temperature extremes. Sixteen indices of extreme temperature are selected. The results are as follows: (1) The occurrence of cold days, cold nights, ice days, frost days and cold spell duration indicator has significantly decreased by −0.84, −2.78, −0.48, −3.29 and −0.67 days per decade, respectively. While the occurrence of warm days, warm nights, summer days, tropical nights, warm spell duration indicator and growing season length shows statistically significant increasing trends at rates of 2.24, 2.86, 2.93, 1.80, 0.83 and 2.30 days per decade, respectively. The tendency rate of the coldest day, coldest night, warmest day, warmest night and diurnal temperature range is 0.33, 0.47, 0.16, 0.19 and −0.07°C per decade, respectively. (2) The magnitudes of changes in cold indices (cold nights, coldest day and coldest night) are obviously greater than those of warm indices (warm nights, warmest day and warmest night). The change ranges of night indices (warm nights and cold nights) are larger than those of day indices (warm days and cold days), which indicates that the change of day and night temperature is asymmetrical. (3) Spatially, the regionally averaged values of cold indices in the upper reaches of the Yangtze River Basin are larger than those in the middle and lower reaches. However, the regionally averaged values of most warm indices (except warm spell duration indicator) and growing season length in the middle and lower reaches are larger than those in the upper reaches. (4) The extreme temperature indices are well correlated with each other except diurnal temperature range.

Environmental assessment of green concrete containing natural zeolite on the global warming index in marine environments

The main air pollutant in the concrete industry is cement responsible for approximately 6% of man-made CO2 emissions. Due to growing concerns for global warming, reducing the consumption of traditional Portland cement and improving mechanical properties of concrete composites have become two important sustainable development issues in recent decades. Zeolite, a type of natural pozzolanic material, has been used as an alternative to improve the durability of concrete. In this study, environmental impact of concrete containing zeolite and conventional one on the global warming potential are assessed by applying life-cycle assessment method. The calculations indicated that replacing 10%, 20% and 30% of cement with zeolite amounted to a 60.3%, 69.7% and 64.3% global warming potential reduction, respectively, which proves the effectiveness of zeolite in making highly environmentally friendly concrete.

The Phytolith and Pollen Record since 10 ka BP from the Lhasa Region, Tibet

Abstract:This paper presents a description of the river terrace at Tangjia Village in Lhasa, Tibet. Selected types of phytolith and pollen were used as proxies to study the paleoclimate in the study area. Ancient climate and vegetation changes since 10 ka BP were examined. The results demonstrated that between 10.2 and 8.9 ka BP, the dominating phytolith was the cold type and the dominating vegetation type was grassland‐forest. This indicated that the climate changed from cool‐humid to cool‐dry and later turned back into a cool‐humid climate. Between 8.9 and 8.1 ka BP, the main types of phytoliths were tooth, dumbbell, and polyhedral. This suggests that the vegetation consisted of forest‐grassland and the period's climate had become warmer. Between 8.1 and 6.7 ka BP, the warm index of phytolith assembelage gradually increased, whereas the spore and pollen assembelage revealed that the vegetation was forest with hardwood. This suggested that the paleoclimate was warmest in this period. The herbaceous vegetation increased gradually, indicating that the climate had become colder since 7.5 ka BP. Between 6.7 and 4.6 ka BP, cold type phytolith such as tooth and cap were found. Simultaneously, the pollen assembelage indicated that the vegetation shifted from grassland to forest and then turned back into grassland. This implies that the climate fluctuated from cold‐dry to cool‐humid. Between 4.6 and 1.9 ka BP, the dominate type of phytolith was cold type and its warm index was in the range 0.04–0.28, suggesting a herbaceous vegetation cover and indicating that the climate was cold. The phytolith warm index from 1.9 ka BP revealed that the climate was continuously decreasing, and most of the pollen assembelage consisted of Chenopodiaceae and Artemisia. This conclusion is in agreement with the phytolith result that indicates that the climate was becoming colder and colder.

Increasing variance in North Pacific climate relates to unprecedented ecosystem variability off California

Changes in variance are infrequently examined in climate change ecology. We tested the hypothesis that recent high variability in demographic attributes of salmon and seabirds off California is related to increasing variability in remote, large-scale forcing in the North Pacific operating through changes in local food webs. Linear, indirect numerical responses between krill (primarily Thysanoessa spinifera) and juvenile rockfish abundance (catch per unit effort (CPUE)) explained >80% of the recent variability in the demography of these pelagic predators. We found no relationships between krill and regional upwelling, though a strong connection to the North Pacific Gyre Oscillation (NPGO) index was established. Variance in NPGO and related central Pacific warming index increased after 1985, whereas variance in the canonical ENSO and Pacific Decadal Oscillation did not change. Anthropogenic global warming or natural climate variability may explain recent intensification of the NPGO and its increasing ecological significance. Assessing non-stationarity in atmospheric-environmental interactions and placing greater emphasis on documenting changes in variance of bio-physical systems will enable insight into complex climate-marine ecosystem dynamics.

Multidecadal signals within co-occurring intertidal barnacles Semibalanus balanoides and Chthamalus spp. linked to the Atlantic Multidecadal Oscillation

Few links have been established between the Atlantic Multidecadal Oscillation and long-term dynamics of marine systems due to the scarcity of sustained biological time-series with sufficient multi-decadal coverage. The abundances of co-occurring boreal and Lusitanian species of barnacle have been recorded annually at a rocky shore in Devon, southwest England since 1953. Multidecadal cycles in relative abundances of the cold-water Semibalanus balanoides and warm-water Chthamalus spp. are strongly correlated with both local sea surface temperatures, and a ‘Warm Index’ of barnacle abundance shows strong links to the basin-scale Atlantic Multidecadal Oscillation. In contrast there are weak or no observed relationships with the North Atlantic Oscillation for either species. The shorter lifecycle of S. balanoides compared to the chthamalids and the increase in spring and summer temperatures to which newly settled S. balanoides recruits have been exposed during the last decade are likely mechanisms by which barnacle densities are responding to low-frequency temperature variability expressed in the Atlantic Multidecadal Oscillation.

A simulation study on the extreme temperature events of the 20th century by using the BCC_AGCM

Extreme temperature events are simulated by using the Beijing Climate Center Atmospheric General Circulation Model (BCC_AGCM) in this paper. The model has been run for 136 yr with the observed external forcing data including solar insolation, greenhouse gases, and monthly sea surface temperature (SST). The daily maximum and minimum temperatures are simulated by the model, and 16 indices representing various extreme temperature events are calculated based on these two variables. The results show that the maximum of daily maximum temperature (TXX), maximum of daily minimum (TNX), minimum of daily maximum (TXN), minimum of daily minimum (TNN), warm days (TX90p), warm nights (TN90p), summer days (SU25), tropical nights (TR20), and warm spell duration index (WSDI) have increasing trends during the 20th century in most regions of the world, while the cold days (TX10p), cold nights (TN10p), and cold spell duration index (CSDI) have decreasing trends.

Changes in daily temperature and precipitation extremes in the Yellow River Basin, China

Spatiotemporal changes in climatic extremes in the Yellow River Basin from 1959 to 2008 were investigated on the basis of a suite of 27 climatic indices derived from daily temperature and precipitation data from 75 meteorological stations with the help of the Mann–Kendall test, linear regression method and GIS technique. Furthermore, the changes in the probability distribution of the extreme indices were examined. The results indicate: (1) The whole basin is dominated by significant increase in the frequency of warm days and warm nights, and dominated by significant decrease in the frequency of cold days and cold nights. Although trends in absolute temperature indices show less spatial coherence compared with that in the percentile-based temperature indices, overall increasing trends can be found in Max Tmax (TXx), Min Tmax (TXn), Max Tmin (TNx) and Min Tmin (TNn). (2) Although the spatial patterns and the number of stations with significant changes for threshold and duration temperature indices are also not identical, general positive trends in warm indices (i.e., summer days (SU25), tropical nights (TR20), warm spell duration indicator and growing season length) and negative trends in cold indices (i.e., frost days, ice days and cold spell duration indicator) can be found in the basin. Annual nighttime temperature has increased at a faster rate than that in daytime temperature, leading to obvious decrease in diurnal temperature range. (3) The changes in precipitation indices are much weaker and less spatially coherent compared with these of temperature indices. For all precipitation indices, only few stations are characterized by significantly change in extreme precipitation, and their spatial patterns are always characterized by irregular and insignificant positive and negative changes. However, generally, changes in precipitation extremes present drying trends, although most of the changes are insignificant. (4) Results at seasonal scale show that warming trends occur for all seasons, particularly in winter. Different from that in other three seasons, general positive trends in max 1-day precipitation (Rx1DAY) and max 5-day precipitation (Rx5DAY) are found in winter. Analysis of changes in probability distributions of indices for 1959–1983 and 1984–2008 indicate a remarkable shift toward warmer condition and a less pronounced tendency toward drier condition during the past decades. The results can provide beneficial reference to water resource and eco-environment management strategies in the Yellow River Basin for associated policymakers and stakeholders.

Change in extreme temperature event frequency over mainland China, 1961−2008

Based on homogeneity-adjusted daily temperature data from national stations, the spatial and temporal change in extreme temperature events in mainland China have been analyzed for the period 1961�2008. The analysis shows that the numbers of frost days and ice days were sig- nificantly reduced, with the most significant reduction generally in northern China for ice days but more extensively across the country for frost days. Summer days and tropical nights significantly in- creased along the middle and lower reaches of the Yangtze River and in southern Southwest China. The maximum values of Tmax (TXx) and Tmin (TNx) and the minimum values of Tmax (TXn) and Tmin (TNn) generally rose, and TXx and TNx significantly increased in northern China, while TXn and TNn significantly increased across the whole country. A significant reduction at a rate of �8.23 d decade �1 (�3.26 d decade -1 ) occurred for cool nights (days), and a significant increase at a rate of 8.16 d decade -1 (5.22 d decade -1 ) occurred for warm nights (days). The reduction of cool nights and cool days occurred mainly in winter, but the increase of warm days and warm nights occurred mostly in autumn and summer. Extreme cold indices were reduced, mainly after the mid-1980s, while extreme warm indices increased remarkably after the mid-1990s. The analysis also shows that, for North China, the urbanization effect on the series of extreme temperature indices was sta- tistically significant for the negative trends of frost days, diurnal temperature range, cool nights and cool days, and for the positive trends of summer days, tropical nights, TNx, TNn, and warm nights.

Understanding and partitioning future climates for Australian regions from CMIP3 using ocean warming indices

The patterns of large-scale climate change over the 21st century simulated by 23 CMIP3 global climate models are analyzed to provide understanding of the range of projected temperature T and precipitation P changes for Australia published in 2007. Means of change, standardized by the global warming, within each of 11 regions are calculated for each model. Correlations between regions across the 23 models indicate that the changes are rather coherent across much of the mainland. The all-Australian average changes are also well correlated with a pattern of tropical sea surface temperatures. A Pacific-Indian Dipole index, representing this pattern, correlates strongly with Australian P. It also correlates well with variables in Southeast Asia. The global warming itself correlates well with Australian warming. These two indices of large-scale ocean warming are used to partition the 23 models into four representative future climates. For Australia overall, these can be described as much warmer and drier, much warmer, warmer and drier, and warmer. The four climates span much of the range of the earlier Australian projections over most of the continent. Further, they may be reproduced by a downscaling model forced with the SST anomalies. An assessment of the realism of the ocean pattern changes has the potential to reduce the uncertainty of projections, both for Australia and beyond.

Characteristics of Climate Warming and Human Body Comfort Index in Beijing during Last 50 Years

In order to analyze the variations of climate warming and human body comfort index on the basis of homogenized correction, the daily meteorological data from 1960 to 2009 in Beijing are examined. According the investigations, some conclusions could be drawn. Firstly, in the last 50 years, the warming rate is 0.39/10a in Beijing, but the warming is unsymmetrical. The warming rate of annual average lowest temperature is obviously higher than that of annual average highest temperature. Secondly, the main discomfort climatic factor is cold discomfort, while thermal discomfort is rare, so is extremely cold discomfort. Thirdly, climate warming and body comfort index are closely correlated in Beijing. The overall trend resulted in by climate warming is the rising in the number of comfortable days, declining in the number of uncomfortable days, and the rate of change is increasing. What’s more, investigations also show that, the heating (cooling) degree days in Beijing dropped (rose) obviously, suggesting that the energy consumption for air conditioners will increase in summer and decrease in winter in Beijing in the future .

Material and energy recovery from Automotive Shredded Residues (ASR) via sequential gasification and combustion

Shredding is the common end-of-life treatment in Europe for dismantled car wrecks. It produces the so-called Automotive Shredded Residue (ASR), usually disposed of in landfill. This paper summarizes the outcome of a study carried out by Politecnico di Milano and LEAP with the support of Actelios SpA on the prospects of a technology based on sequential gasification and combustion of this specific waste stream. Its application to the treatment of ASR allows the recovery of large fractions of metals as non-oxidized, easily marketable secondary raw materials, the vitrification of most of the ash content and the production of power via a steam cycle. Results show that despite the unfavourable characteristics of ASR, the proposed technology can reach appealing energy performances. Three of four environmental impact indicators and the cumulative energy demand index are favourable, the main positive contributes being electricity production and metal recovery (mainly aluminium and copper). The only unfavourable indicator is the global warming index because, since most of the carbon in ASR comes from fossil sources, the carbon dioxide emissions at the stack of the thermal treatment plant are mainly non-renewable and, at the same time, the avoided biogas production from the alternative disposal route of landfilling is minor.

Influence of design high water level, warm index, and maximum snow depth on deterioration rate of wooden crib dams

Influence of design high water level, warm index, and maximum snow depth on deterioration rate of wooden crib dams

Anthropogenic effects on the subsurface thermal and groundwater environments in Osaka, Japan and Bangkok, Thailand

Anthropogenic effects in both Osaka and Bangkok were evaluated to compare the relationships between subsurface environment and the development stage of both cities. Subsurface thermal anomalies due to heat island effects were found in both cities. The Surface Warming Index (SWI), the departure depth from the steady geothermal gradient, was used as an indicator of the heat island effect. SWI increases (deeper) with the magnitude of heat island effect and the elapsed time starting from the surface warming. Distributions of subsurface thermal anomalies due to the heat island effect agreed well with the distribution of changes in air temperature due to the same process, which is described by the distribution of population density in both Osaka and Bangkok. Different time lags between groundwater depression and subsidence in the two cities was found. This is attributed to differences in hydrogeologic characters, such as porosity and hydraulic conductivity. We find that differences in subsurface degradations in Osaka and Bangkok, including subsurface thermal anomalies, groundwater depression, and land subsidence, depends on the difference of the development stage of urbanization and hydrogeological characters.

The 1950-1998 warm ENSO events and regional implications to river flow variability in Southern Africa

The variability of annual river runoff and its possible association with the 1950-1998 seasonal El Niño/Southern Oscillation (ENSO) is investigated in 502 rivers gauged in 9 countries of the Southern African region. We found some evidence of possible links between available surface water resources in terms of mean annual runoff and warm ENSO events. This was revealed by the existence of strong and nearly-strong positive linear correlation between annual discharges and the warm seasonal ENSO indices explained by the sea level pressure (SLP) data. Of the 502 rivers we considered, 150 rivers exhibit strong positive correlation between the December to February quarter ENSO indices and the annual runoff – with 25% of the variance in annual runoff being accounted for by the warm ENSO events. A relatively weaker positive correlation also occurred in 174 rivers we considered. The strong positive correlation occurs in parts of Zambia, Namibia, Mozambique and the lowveld in South Africa. In these parts of Southern Africa, there is evidence of a general decline in annual runoff after the mid-1970s compared to the period before it. These revelations are explored and are found to be partly explained by the high frequency of drought-related warm ENSO phenomena that occurred during the same period. Water SA Vol.32 (4) 2006: pp.459-463

A Flexible Global Warming Index for Use in an Integrated Approach to Climate Change Assessment

Global Warming Potential (GWP) is an index used to measure the cumulative radiative forcing of a tonne of greenhouse house gas (GHG) relative to that of a ‘reference’ gas (CO2). Under the Kyoto Protocol, GWP can be used as a fixed index to govern the trade-off between different GHGs in a multi-gas approach to GHGs abatement. The use of fixed GWPs has been criticized for not being very cost effective compared to the use of some flexible indices. To gain wider acceptance, however, a flexible index must also prove to be easy to use, and the economic gains from its adoption must be significant. In this paper, we develop a flexible index based on the concept of marginal rather than cumulative or average global warming potentials. These marginal global warming potentials (MGWPs) can be endogenously determined within a climate model given a particular climate objective based on radiative forcing level. The MGPWs are then linked to the marginal abatement costs of the GHGs, which are also endogenously determined within an economic model. When the two concepts are linked in this way, the result is a cost-effective way of achieving a particular climate change objective with multigas abatement. We show that the savings in costs when using this flexible MGPWs can be significant, and more importantly, they are not uniformly distributed across different regions.

Evaluating sustainability of household consumption—Using DEA to assess environmental performance

We assess environmental performance across product types and across household types in order to evaluate environmental pressure from human activities. To so do, we combine family budget statistics, input–output tables, energy and material flow matrices, various types of emissions and environmental effects indices for various effect types (e.g. a global warming potential index, an ozone depletion potential index, etc). Subsequently, using DEA (Data Envelopment Analysis), we use these weighted environmental effects indices to form one environ-mental performance score for each family type and product type. We find that the environmental performance of each family type changes considerably across environmental effect types. The analysis of the overall environmental performance scores shows that families living in urban flats, especially the young and elderly families, have the most environmentally friendly consum-ption pattern. Middle income families living in houses have the least environmentally friendly consumer basket, and these families constitute a high share of all families in Denmark.

ＴＭの熱赤外データとＡＭｅＤＡＳの気温データを利用した東京圏のヒートアイランドの広域化の解析

The relationship between temperature changes and the expansion of Tokyo Metropolitan Area was studied using multi-temporal Landsat Thematic Mapper (TM) satellite images. The correlation between the ratio of green covering and brightness temperature was assumed to be an index of urbanization, thus, the relation between the ratio of green covering and air temperature in different seasons was verified around the Automated Meteorological Data Acquisition System (AMeDAS) observation point in Tokyo Metropolitan Area. The area located in NDVI >0.1 was assumed to be a vegetation region, on the other hand, the vegetation in the concentric circle of 0.6 km from the point where AMeDAS was observed, had been extracted from multitemporal TM data.The interrelationships between vegetated area and air temperature in Tokyo metropolis were established by comparing the daily average maximum temperature (Tmax), the daily average minimum temperature (Tmin) the average temperature at 9 p.m. (T21), during winter, summer and autumn using TM images and AMeDAS data. As a result, the strong correlation between a green covering and the daily minimum temperature was revealed at each season. In contrast, such a relation was not observed between the ratio of green covering and the maximum temperature.The variation of brightness temperature of the Tokyo area was estimated using thermal infrared data of TM band 6. Because the DN value changes with the state of performance degradation of the sensor or the atmosphere interface, the absolute value of derived temperature can not be compared to the heat island phenomena. Therefore, the relative change of DN value of thermal infrared data was ideal for studying the heat island phenomena. DN values were extracted from 2 Landsat TM night images acquired on August 1984 and August 1994, which had been used to estimate the expansion of the heat island phenomena.Relative Warming Index (RWI) of the AMeDAS observation point was also evaluated from the rate of change (19841994) of the daily minimum temperature of Tokyo (Otemachi). The rate of change of RWI corresponded to the distribution of differences in brightness temperature around Tokyo. The spatial analysis of relative warming index (RWI) for the 10 years of observations suggests that the warming rate of suburban area was much more pronounced than that of central Tokyo, and the rural side of the suburban area recorded a relatively low RWI than that of the same facing towards central Tokyo. The results from satellite images show of consistency with meteorological records.