Daily Temperature Changes Research Articles

Hatching plasticity in the tropical gastropod Nerita scabricosta

AbstractHatching plasticity has been documented in diverse terrestrial and freshwater taxa, but in few marine invertebrates. Anecdotal observations over the last 80 years have suggested that intertidal neritid snails may produce encapsulated embryos able to significantly delay hatching. The cause for delays and the cues that trigger hatching are unknown, but temperature, salinity, and wave action have been suggested to play a role. We followed individual egg capsules of Nerita scabricosta in 16 tide pools to document the variation in natural time to hatching and to determine if large delays in hatching occur in the field. Hatching occurred after about 30 d and varied significantly among tide pools in the field. Average time to hatching in each pool was not correlated with presence of potential predators, temperature, salinity, or pool size. We also compared hatching time between egg capsules in the field to those kept in the laboratory at a constant temperature in motionless water, and to those kept in the laboratory with sudden daily water motion and temperature changes. There was no significant difference in the hatching rate between the two laboratory treatments, but capsules took, on average, twice as long to hatch in the laboratory as in the field. Observations of developing embryos showed that embryos in the field develop slowly and continuously until hatching, but embryos in the laboratory reach the hatching stage during the first month of development and remain in stasis after that. Instances of hatching plasticity in benthic marine invertebrates, like the one in N. scabricosta, could greatly enhance our ability to investigate the costs and benefits of benthic versus planktonic development, a long‐standing area of interest for invertebrate larval biologists.

Variability for a day or a season

Physiological Ecology Species that experience larger seasonal climatic fluctuations are likely to be more physiologically flexible and thus likely to occur across a wider elevational range. Daily changes in temperature are also common but have rarely been considered. Chan et al. used a global data set of vertebrates to look at how these two different sets of variation affect a species' elevational distribution (see the Perspective by Perez et al. ). Unexpectedly, larger daily fluctuations were associated with smaller elevational distributions. Thus, specialists are favored where daily fluctuations are dominant, whereas generalists are favored where seasonal fluctuations are the main climate influence. Science , this issue p. [1437][1]; see also p. [1392][2] [1]: /lookup/doi/10.1126/science.aab4119 [2]: /lookup/doi/10.1126/science.aaf3343

Climate specific thermomechanical fatigue of flat plate photovoltaic module solder joints

FEM simulations of PbSn solder fatigue damage are used to evaluate seven cities that represent a variety of climatic zones. It is shown that the rate of solder fatigue damage is not ranked with the cities' climate designations. For an accurate ranking, the mean maximum daily temperature, daily temperature change and a characteristic of clouding events are all required. A physics-based empirical equation is presented that accurately calculates solder fatigue damage according to these three factors. An FEM comparison of solder damage accumulated through service and thermal cycling demonstrates the number of cycles required for an equivalent exposure. For an equivalent 25-year exposure, the number of thermal cycles (−40°C to 85°C) required ranged from roughly 100 to 630 for the cities examined. It is demonstrated that increasing the maximum cycle temperature may significantly reduce the number of thermal cycles required for an equivalent exposure.

Examining diel patterns of soil and xylem moisture using electrical resistivity imaging

Summary The feedbacks among forest transpiration, soil moisture, and subsurface flowpaths are poorly understood. We investigate how soil moisture is affected by daily transpiration using time-lapse electrical resistivity imaging (ERI) on a highly instrumented ponderosa pine and the surrounding soil throughout the growing season. By comparing sap flow measurements to the ERI data, we find that periods of high sap flow within the diel cycle are aligned with decreases in ground electrical conductivity and soil moisture due to drying of the soil during moisture uptake. As sap flow decreases during the night, the ground conductivity increases as the soil moisture is replenished. The mean and variance of the ground conductivity decreases into the summer dry season, indicating drier soil and smaller diel fluctuations in soil moisture as the summer progresses. Sap flow did not significantly decrease through the summer suggesting use of a water source deeper than 60 cm to maintain transpiration during times of shallow soil moisture depletion. ERI captured spatiotemporal variability of soil moisture on daily and seasonal timescales. ERI data on the tree showed a diel cycle of conductivity, interpreted as changes in water content due to transpiration, but changes in sap flow throughout the season could not be interpreted from ERI inversions alone due to daily temperature changes.

Multi-Physics Calculation and Contact Degradation Mechanism Evolution of GIB Connector Under Daily Cyclic Loading

A 3-D electromagnetic-thermal-mechanical coupling finite element model of a gas-insulated bus plug-in connector is proposed in this paper with a subsequent analysis for the contact fatigue mechanism. Special attention has been paid to the contact degradation mechanism under normal cyclic operation conditions, which is important for the optimal designing and condition monitoring of the equipment. The current constriction effect and the contact resistance are considered through modeling the equivalent contact bridges between contact interfaces, and the current densities derived from the electromagnetic field are applied as load inputs in a electrical-thermal-mechanical analysis where varying of friction coefficient is considered. The validity of the calculation model has been demonstrated by temperature rise and relative motion experiments, and the influence of daily changing current and environmental temperature on the thermal and mechanical characteristics of plug-in connector has been analyzed. Analysis results show that the temperature rise among different contact fingers of plug-in connector is not the same with different contact forces, and the plastic deformation can be induced on contact spots. The insert depth of connector can be changed under the action of alternating thermal loading induced by daily change of current and environmental temperature, leading to contact degradation and overheating fault of plug-in connector.

Cool night-time temperatures induce the expression of CONSTANS and FLOWERING LOCUS T to regulate flowering inArabidopsis.

Day length and ambient temperature are major stimuli controlling flowering time. To understand flowering mechanisms in more natural conditions, we explored the effect of daily light and temperature changes on Arabidopsis thaliana. Seedlings were exposed to different day/night temperature and day-length treatments to assess expression changes in flowering genes. Cooler temperature treatments increased CONSTANS (CO) transcript levels at night. Night-time CO induction was diminished in flowering bhlh (fbh)-quadruple mutants. FLOWERING LOCUS T (FT) transcript levels were reduced at dusk, but increased at the end of cooler nights. The dusk suppression, which was alleviated in short vegetative phase (svp) mutants, occurred particularly in younger seedlings, whereas the increase during the night continued over 2wk. Cooler temperature treatments altered the levels of FLOWERING LOCUS M-β (FLM-β) and FLM-δ splice variants. FT levels correlated strongly with flowering time across treatments. Day/night temperature changes modulate photoperiodic flowering by changing FT accumulation patterns. Cooler night-time temperatures enhance FLOWERING BHLH (FBH)-dependent induction of CO and consequently increase CO protein. When plants are young, cooler temperatures suppress FT at dusk through SHORT VEGETATIVE PHASE (SVP) function, perhaps to suppress precocious flowering. Our results suggest day length and diurnal temperature changes combine to modulate FT and flowering time.

Assessment of the effect of cold and hot temperatures on mortality in Ontario, Canada: a population-based study

Ambient high temperature is associated with death; however, heat-related risk of death has not been quantified systematically in Ontario, the most populous province in Canada. Less is known about cold-related risk in this population. Our objective was to quantify the health impact from cold and hot temperatures in Ontario. The study population consisted of all residents of Ontario who died between Jan. 1, 1996, and Dec. 31, 2010, from any nonaccidental cause. A case-crossover analysis was applied to assess the relation between daily temperature fluctuation and deaths from nonaccidental and selected causes in cold (December-February) and warm (June-August) seasons, respectively, adjusting for various potential confounders. Risk estimates were obtained for each census division, then pooled across Ontario. We examined potential effect modification for selected comorbidities and sociodemographic characteristics. In warm seasons, each 5°C increase in daily mean temperature was associated with a 2.5% increase in nonaccidental deaths (95% confidence interval [CI] = 1.3% to 3.8%) on the day of exposure (lag 0). In cold seasons, each 5°C decrease in daily temperature was associated with a 3.0% (95% CI 1.8% to 4.2%) increase in nonaccidental deaths, which persisted over 7 days (lag 0-6). The cold-related effects (lag 0-6) were stronger for cardiovascular-related deaths (any cardiovascular death: 4.1%, 95% CI 2.3% to 5.9%; ischemic heart disease: 5.8%, 95% CI 3.6% to 8.1%), especially among people less than 65 years of age (8.0%, 95% CI 3.0% to 13.0%). Conversely, heat most strongly increased respiratory-related deaths during admission to hospital (26.0%, 95% CI 0% to 61.4%). Across Ontario, each 5°C change in daily temperature was estimated to induce 7 excess deaths per day in cold seasons and 4 excess deaths in warm seasons. Heat contributed to excess deaths in Ontario, although the effect of cold weather appeared to be greater. Further work is required to better define high-risk subgroups, which might include the homeless and people with inadequately heated housing.

Midlatitude daily summer temperatures reshaped by soil moisture under climate change

AbstractProjected changes in daily temperatures are highly model dependent, particularly in the summer midlatitudes where the spread in the response of heat waves represents a major obstacle for the design of adaptation strategies. Understanding the main reasons for such uncertainties is obviously a research priority. Here we use a set of global atmospheric simulations to assess the contribution of the soil moisture feedback to changes in the full distribution of daily maximum summer temperatures projected in the late 21st century. Results show that this feedback (i) accounts for up to one third of the mean increase in daily maximum temperatures, (ii) dominates changes in the shape of the distribution, and (iii) explains about half of the increase in the severity of heat waves over densely populated areas of the northern midlatitudes. A dedicated intercomparison project is therefore needed to assess and constrain land surface feedbacks in the new generation Earth System Models.

Managing impact of climatic vagaries on the productivity of wheat and mustard in India

Wheat and mustard crop is highly vulnerable, particularly in the semi-arid and arid regions of India. The climate is warming through the processes such as CO2 and changed pattern of temperature and precipitation resulting in heat and drought stresses, respectively. The effect of increasing temperature during grain filling stage of wheat causes substantial reduction in grain yield. The effect of low temperature (frost) during podding and seed development stage in mustard causes freezing injury in seeds and sizable reduction in seed yield. In this review paper response of wheat and mustard crop to weather extremes and management practices such as time of sowing, selection of resistance cultivars, mulching, seed priming, foliar spray of salts, use of extra irrigation water, foliar spray of micronutrients, sprinkler, wind barrier etc. to mitigate the temperature and moisture stress effect on the productivity of wheat and mustard crop have been discussed. Above ground dry weight of wheat and its rate decreased with increasing water stress at each stage. The averaged values of damage threshold temperatures compiled from the literature were 31 °C for flowering and 35 °C for grain filling of wheat. Changes in average daily maximum temperature during flowering and grain filling had a negative effect on grain yield of 518 kg/ha and 1140 kg/ha, respectively for every 1 degree increase in average maximum temperature in South Australia. Temperature rise would be most harmful for the crop in eastern region, followed by central and northern India, where winter season temperature is comparatively higher than northern region. Rainfed mustard was less vulnerable to temperature rise in northern India as compared to other two central and eastern India. Rise in atmospheric temperature reduced leaf area index, grain number as well as weight of grains which was in turn reflected in yield of mustard crop. Seed yield reduction occurred by low water availability during stem elongation, flowering and pod development in mustard. Priming with moringa water extract and ascorbate substantially improved the tissue water status, membrane stability, gas exchange, water productivity of the plant. Late sown wheat crop faces high temperature stress during ripening phase. Delayed sowing reduces the tillering period and hot weather during critical period of grain filling lead to forced maturity thereby reduces the grain yield. Application of mulches in wheat produced higher grain yield over without much wheat. Organic mulches provided better soil water status and improved plant canopy in terms of biomass, root growth, leaf area index and grain yield as compared to inorganic mulch. The foliar spray of KNO3 (0.5%) at 50 per cent flowering stage, 1.0 per cent KNO3 during anthesis stage, 2.5 mM of arginine, spray of zinc, extra irrigation water during grain filling stage increased the productivity of wheat under high temperature stress.
 Light irrigation in mustard crop one day before frost occurrence protects from frost damage by improving heat transfer and heat capacity. Plastic mulch raises the surface temperature of the soil nearly 10 °C over bare soil. Smoke particles are usually less than 1 µm in size, reflect visible radiation but trap the long wave radiation and so are effective in preventing rapid cooling of surface near ground. Mixing air and liquid materials in the right proportion to create many small bubbles is the secret to generate foam with low thermal conductivity. Organic mulches (straw and saw dust) provided better soil water status over ash mulch.

Comparisons of Ground-Based and Building-Based CORS: A Case Study in the Region of Puerto Rico and the Virgin Islands

AbstractThis study investigated long-term observations from three pairs of closely spaced, continuously operating reference stations (CORS): STVI and VITH (2008–2014, 0.6 km apart), BYSP and PRHL (2008–2014, 3.2 km apart), and CRO1 and VIKH (1995–2014, 23 km apart), in the region of Puerto Rico and Virgin Islands. The Global Positioning System (GPS) antennas of STVI, BYSP, and CRO1 are mounted on ground-based monuments. The GPS antennas of VITH, PRHL, and VIKH are mounted on building-based monuments. This study indicated that there is no considerable difference between building-based and ground-based CORS with regard to the precision of daily positions and the reliability of long-term site velocities. The amplitude of thermal movements associated with daily temperature changes and the wind drift associated with air pressure change from a 2-story concrete building fell below the detectable levels of the present high-precision GPS technique determined by Precise Point Positioning (PPP) processing. Further a...

Daily temperature change in relation to the risk of childhood bacillary dysentery among different age groups and sexes in a temperate city in China

BackgroundIn recent years, many studies have found that ambient temperature is significantly associated with bacillary dysentery (BD). However, there is limited evidence on the relationship between temperature and childhood BD in temperate areas. ObjectivesTo investigate the relationship between daily mean temperature (MT) and childhood BD in China. MethodsData on daily MT and childhood BD between 2006 and 2012 were collected from the Bureau of Meteorology and the Centre for Disease Control and Prevention in Hefei, Anhui Province, China. A Poisson generalized linear regression model combined with a distributed lag non-linear model was used to analyse the effects of temperature on childhood BD across different age and sex subgroups. ResultsAn increase in temperature was significantly associated with childhood BD, and each 1 °C increase corresponded to an increase of 1.58% [95% confidence interval (CI) 0.46–2.71%] in the number of cases of BD. Children aged 0–5 years and girls were particularly sensitive to the effects of temperature. ConclusionsHigh temperatures may increase the risk of childhood BD in Hefei. Children aged 0–5 years and girls appear to be particularly sensitive to the effects of high temperature.

Role of the Suprachiasmatic and Arcuate Nuclei in Diurnal Temperature Regulation in the Rat.

When circadian and metabolic systems are not well synchronized, individuals may develop metabolic diseases. The underlying mechanisms are unknown. Here, we demonstrate that the balance between the releases of neuropeptides derived from the biological clock and from a metabolic sensory organ as the arcuate nucleus, are essential for an adequate temperature control. These observations show that brain areas involved in circadian and metabolic functions of the body need to interact to produce a coherent arrangement of physiological processes associated with temperature control.

ENERGY EFFICIENCY HOUSE WITH COMPLEX USE OF RENEWABLE ENERGY IN HARSH ENVIRONMENTS

The mathematical model and algorithms developed for the energy optimization of the building areas without connection to centralized electricity and gas networks. The model takes into account particular climate conditions characteristic of sharply continental climate: big seasonal and daily changes in temperature, extremely low temperatures in winter. On the basis of the calculations and optimization of the model of joint use of a number of power supply system based on renewable energy sources (wind turbines, solar collectors, photovoltaic cells, heat pump) with a diesel generator cogeneration source of electricity and heat. It is shown that this model reduces the energy consumption of diesel fuel and the environmental burden on the territory of more than 1.5 times. The calculation results are the basis for energy efficiency projects farmhouse, which was implemented in the Sverdlovsk region (the village Rising). In 2009, the project received the National Environmental Award Vernadsky.

Effects of Temperature and Sunshine Hours During Grain Filling Stage on the Quality-Related Traits of High Quality Rice Varieties in Korea

벼 등숙기간 및 등숙기 기간별 기온과 일조시간이 쌀 품질 특성에 미치는 영향을 알아보기 위하여 전국 8개도 24개 지역에서 고품질 벼 11품종을 이용하여 2013-2014년에 시험한 결과는 다음과 같다. 1. 품종, 지역 및 연차별 시험성적을 모두 합하였을 때, 출수기, 출수 후 40일간 평균기온 및 일조시간의 범위는 각각 7월 23일~9월 4일, <TEX>$18.8{\sim}26.4^{\circ}C$</TEX>, 3.9~8.0시간/일이었다. 2. 성적을 모두 합하였을 때, 특성별 범위는 등숙비율 74.2~97.9%, 현미 천립중 19.6~26.1 g, 완전미 비율 61.4~98.5%, 완전미 수량 276~701 kg/10a, 쌀 단백질 4.8~8.3%, Toyo Mido Meter 값 66.1~91.5였다. 3. 완전미 비율, 완전미 수량, 쌀 단백질 및 Toyo Mido Meter 값은 출수 후 40일간의 등숙 최적온도인 <TEX>$22.6^{\circ}C$</TEX>보다 낮은 온도에서 높아졌으며, 쌀 외관품위와 밥맛을 고려한 출수 후 40일간의 최적 일조시간은 6.0~6.1시간/일로 평가되었다. 4. 쌀 단백질은 출수 후 40일간의 평균기온 및 일조시간과 유의한 관계를 보인 품종이 전체 11품종 중 각각 8개와 9개로, 다른 특성에 비해 많았다. 5. 쌀 단백질은 등숙 초기의 평균기온 및 등숙 초 중기의 일조시간에, 완전미 비율은 등숙 초기의 평균기온 및 일조시간에 상대적으로 더 큰 영향을 받았다. Relationship between grain quality-related traits and daily mean temperature/sunshine hours during grain filling stage was analyzed using eleven high quality rice varieties at 24 experimental sites through eight provinces of Korea in 2013~2014. In the data set pooled across varieties, experimental sites and years, grain quality-related traits such as percentage of head rice (PHR), head rice yield (HRY), protein in milled rice (PRO) and Toyo Mido Meter glossiness value (TGV) were higher at the temperature lower than <TEX>$22.6^{\circ}C$</TEX> for 40 days after flowering (DAF), which was optimum for percentage of grain filling in this study. Optimum sunshine hours for 40 DAF were <TEX>$6.0{\sim}6.1\;hr\;d^{-1}$</TEX>when considered PHR, HRY and TGV. PRO was associated with daily mean temperature and sunshine hours for 40 DAF in more varieties than the other traits. PRO was closely correlated with daily mean temperature during early filling stage and sunshine hours during early to mid filling stage, compared to other stages during grain filling. It is concluded that general trend in the variation of grain quality-related traits could be explained by the changes in daily mean temperature and sunshine hours during grain filling. In addition, climate conditions during early grain filling stage played important roles to enhance grain quality.

Modelling temperature change downstream of forest harvest using Newton's law of cooling

We adapted Newton's law of cooling to model downstream water temperature change in response to stream-adjacent forest harvest on small and medium streams (average 327 ha in size) throughout the Oregon Coast Range, USA. The model requires measured stream gradient, width, depth and upstream control reach temperatures as inputs and contains two free parameters, which were determined by fitting the model to measured stream temperature data. This model reproduces the measured downstream temperature responses to within 0.4 °C for 15 of the 16 streams studied and provides insight into the physical sources of site-to-site variation among those responses. We also use the model to examine how the pre-harvest to post-harvest change in daily maximum stream temperature depends on distance from the harvest reach. The model suggests that the pre-harvest to post-harvest temperature change approximately 300 m downstream of the harvest will range from roughly 82% to less than 1% of that temperature change that occurred within the harvest reach, depending primarily on the downstream width, depth and gradient. Using study-averaged values for these channel characteristics, the model suggests that for a stream representative of those in the study, the temperature change approximately 300 m downstream of the harvest will be 56% of the temperature change that occurred within the harvest reach. This adapted Newton's law of cooling procedure represents a highly practical means for predicting stream temperature behaviour downstream of timber harvests relative to conventional heat budget approaches and is informative of the dominant processes affecting stream temperature. Copyright © 2015 John Wiley & Sons, Ltd.

The Association Between Meteorological Factors and Stone-Associated Pancreatohepatobiliary Disease

Introduction: Gallstone-associated cholecystitis and acute pancreatitis were reported to develop more frequently in summer and spring, respectively. However, there have been no reports confirming the association between meteorological factors and stone-associated pancreatohepatobiliary disease (SAPHBD), which includes acute cholelithiasis, acute cholecystitis, acute cholangitis, and acute pancreatitis. The aim of this study was to assess meteorological risk factors for developing SAPHBD. Methods: Retrospective longitudinal study was performed in a tertiary referral center in Tokyo, Japan from January 1 2012 to December 31 2013. In all SAPHBD patients, stones were confirmed by ERCP and/or percutaneous transhepatic biliary drainage (PTBD). Patients with neoplastic lesions or unclear onsets, were excluded. We collected daily meteorological data of Tokyo from the Japan Meteorological Agency calculating daily change of temperature, relative humidity, and barometric pressure. Bivariate analyses were performed through Spearman's correlation coefficient (SCC). Multivariate analysis was conducted by Poisson regression for calculating adjusted incidence rate ratio (IRR). Results: 437 patients underwent ERCP and/or PTBD, and 141 were diagnosed with SAPHBD [cholelithiasis (17%), cholecystitis (12%), cholangititis (61%), pancreatitis (10%)]. The mean age (SD) was 71 (14) years-old and 88 (62%) was male. Mean (SD) of temperature [celsius], humididy [%], and barometric pressure [hPa] was 17 (8), 62 (16), and 1008 (7), respectively. Mean (SD) daily change of temperature [celsius], humididy [%], and barometric pressure [hPa] was 7 (2), 32 (12), and 7 (5), respectively. SCC of daily change of temperature, humidity, and barometric pressure was 0.037, 0.011, and 0.089, respectively. Adjusted IRR [95%CI] of temperature, humidity, and barometric pressure using multiple Poisson regression was 0.98 [0.96, 1.0], 1.0 [0.997, 1.02], and 0.99 [0.96, 1.01]. Adjusted IRR [95%CI] of daily change of temperature, humidity, and barometric pressure was 1.06 [0.98, 1.1], 0.99 [0.98, 1.01], and 1.06 [1.03, 1.09], respectively. Conclusion: Daily change of barometric pressure is significantly associated with SAPHBD development. Lower temperature is also marginally associated with SAPHBD. These association can be applied for constructing local medical emergency system.

Investigating the observed sensitivities of air-quality extremes to meteorological drivers via quantile regression

Abstract. Air pollution variability is strongly dependent on meteorology. However, quantifying the impacts of changes in regional climatology on pollution extremes can be difficult due to the many non-linear and competing meteorological influences on the production, transport, and removal of pollutant species. Furthermore, observed pollutant levels at many sites show sensitivities at the extremes that differ from those of the overall mean, indicating relationships that would be poorly characterized by simple linear regressions. To address this challenge, we apply quantile regression to observed daily ozone (O3) and fine particulate matter (PM2.5) levels and reanalysis meteorological fields in the USA over the past decade to specifically identify the meteorological sensitivities of higher pollutant levels. From an initial set of over 1700 possible meteorological indicators (including 28 meteorological variables with 63 different temporal options), we generate reduced sets of O3 and PM2.5 indicators for both summer and winter months, analyzing pollutant sensitivities to each for response quantiles ranging from 2 to 98 %. Primary covariates connected to high-quantile O3 levels include temperature and relative humidity in the summer, while winter O3 levels are most commonly associated with incoming radiation flux. Covariates associated with summer PM2.5 include temperature, wind speed, and tropospheric stability at many locations, while stability, humidity, and planetary boundary layer height are the key covariates most frequently associated with winter PM2.5. We find key differences in covariate sensitivities across regions and quantiles. For example, we find nationally averaged sensitivities of 95th percentile summer O3 to changes in maximum daily temperature of approximately 0.9 ppb °C−1, while the sensitivity of 50th percentile summer O3 (the annual median) is only 0.6 ppb °C−1. This gap points to differing sensitivities within various percentiles of the pollutant distribution, highlighting the need for statistical tools capable of identifying meteorological impacts across the entire response spectrum.

Evaluation of the effect of Siberia’s high pressure extension on daily minimum temperature changes in Iran

One of the climatic phenomena that affects low temperatures in Iran is the penetration of tongues of high pressures from Siberia during the cold period of the year. Therefore, in order to investigate the effect of Siberia’s high pressure on the occurrence of low temperatures in Iran, air pressure at sea level for the region from 45 to 125°E and 25 to 65°N within the time range of one day and the location range of 2.5°, 561 grids for the month of December from the years 1948 to 2010 was extracted from the NOAA website and evaluated. It is necessary to explain that all pressure data for the studied range were classified into clusters using statistical analysis. Seven of these clusters were chosen as dominant. Of these, three prominent, important patterns, including clusters 3, 4, and 6, together account for 62.26 % our records in during December. In these three patterns, the effect of Siberia’s high pressure on the occurrence of low temperatures in Iran during December is more visible compared to the other patterns. On the other hand, simultaneous with the occurrence of the fourth cluster, with 99 % of Iran’s entire area, the maximum area of the country experiences below-average temperatures, and simultaneous with the occurrence of the second cluster, only 3 % of the entire area of Iran experiences below-average temperatures during December. In addition, we discovered a significant trend of increasing temperatures for most of the clusters in Iran, which can be attributed to global warming.

Forecasting method of ice blocks fall using logistic model and melting degree–days calculation: a case study in northern Gaspésie, Québec, Canada

Ice blocks fall is a serious natural hazard that frequently happens in mountainous cold region. The ice blocks result from the melting and collapse of rockwall icings (ice walls or frozen waterfalls). Environment Canada weather data were analyzed for 440 cases of ice blocks fall events reported in northern Gaspesie by the “Ministere des Transports du Quebec.” The available meteorological variables were used to develop an ice blocks fall forecasting tool. The analysis shows that the ice blocks falls are mainly controlled by an increase in the air temperature above the melting point of ice. The temperature variations and the heat transfer into the ice bodies can be expressed by the melting degree–days (DDmelt). The best logistic model was derived by testing a number of combinations of variables against the database (ice blocks fall events and meteorological data). Feeding this model with the meteorological data and using the recorded evolution of DDmelt as a complementary predictive tool allow the forecast of the most hazardous periods on a regional scale, i.e., along the northern Gaspesie roads and on a local scale, i.e., the collapse of some of the most problematic rockwall icings. We also discuss the effects of large daily temperature changes such as drastic drops of temperature below 0 °C and freeze–thaw cycles on the opening of cracks and the collapse of unstable ice structures such as freestanding ice formations.

The impact of the mean daily air temperature change on electricity consumption

This paper presents the analysis of the impact of weather conditions on the consumption of electricity in the City of Kragujevac (the Republic of Serbia) during the seven-year period from 2006 to 2012. It points out the mean daily air temperature as the most influential climate (meteorological) parameter, and gives an overview of deviations from the mean values compared to the reference period. Increases and decreases in the power consumption depending on the deviations of the mean daily temperature from the normal (average) values are also indicated. In periods of strong and long-lasting cold spells in the winter months, there is increased power consumption as a result of heating in residential and office buildings. During extremely hot and long summer periods, there is also a tendency of increasing electricity consumption because of home air conditioning. In the transitional seasons, especially when the remote heating system is not active, sudden and relatively long periods of cold weather also have a significant influence on increases in the electricity consumption. A timely and accurate weather forecast can certainly help prevent the electrical power system overload and reduce the risk of possible power system damages.