Science.gov

Sample records for air temperature warming

  1. Air moisture control on ocean surface temperature, hidden key to the warm bias enigma

    NASA Astrophysics Data System (ADS)

    Hourdin, Frédéric; Gǎinusǎ-Bogdan, Alina; Braconnot, Pascale; Dufresne, Jean-Louis; Traore, Aboul-Khadre; Rio, Catherine

    2015-12-01

    The systematic overestimation by climate models of the surface temperature over the eastern tropical oceans is generally attributed to an insufficient oceanic cooling or to an underestimation of stratocumulus clouds. We show that surface evaporation contributes as much as clouds to the dispersion of the warm bias intensity in a multimodel simulations ensemble. The models with the largest warm biases are those with the highest surface heating by radiation and lowest evaporative cooling in atmospheric simulations with prescribed sea surface temperatures. Surface evaporation also controls the amplitude of the surface temperature response to this overestimated heating, when the atmosphere is coupled to an ocean. Evaporation increases with temperature both because of increasing saturation humidity and of an unexpected drying of the near-surface air. Both the origin of the bias and this temperature adjustment point to the key role of near-surface relative humidity and its control by the atmospheric model.

  2. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature

    PubMed Central

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    Global analyses of surface mean air temperature (Tm) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the “warming hole” over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of Tm. Existing global analyses calculate Tm from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using Tm calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2. PMID:26198976

  3. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Zhou, Chunlüe

    2015-07-01

    Global analyses of surface mean air temperature (Tm) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the “warming hole” over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of Tm. Existing global analyses calculate Tm from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using Tm calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2.

  4. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Zhou, Chunlüe

    2016-04-01

    Global analyses of surface mean air temperature (Tm) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the "warming hole" over the central U.S., are still under debate. Here we show these regional contrasts depends on the calculation methods of Tm. Existing global analyses calculated Tm from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using Tm calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2.

  5. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature.

    PubMed

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    Global analyses of surface mean air temperature (T(m)) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the "warming hole" over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of T(m). Existing global analyses calculate T(m) from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using T(m) calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2. PMID:26198976

  6. Potential causes of differences between ground and surface air temperature warming across different ecozones in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Majorowicz, Jacek A.; Skinner, Walter R.

    1997-10-01

    Analysis and modelling of temperature anomalies from 25 selected deep wells in Alberta show that the differences between GST (ground surface temperature) warming for the northern Boreal Forest ecozone and the combined Prairie Grassland ecozone and Aspen Parkland transition region to the south occur during the latter half of this century. This corresponds with recent changes in surface albedo resulting from permanent land development in the northern areas and also to increases in natural forest fires in the past 20 years. Differences between GST and SAT (surface air temperature) warming are much higher in the Boreal Forest ecozone than in the Prairie Grassland ecozone and Aspen Parkland transition region. Various hypotheses which could account for the existing differences between the GST and SAT warming in the different ecozones of Alberta, and western Canada in general, are tested. Analysis of existing data on soil temperature, hydrological piezometric surfaces, snowfall and moisture patterns, and land clearing and forest fires, indicate that large areas of Alberta, characterised by anomalous GST warming, have experienced widespread changes to the surface landscape in this century. It is postulated that this has resulted in a lower surface albedo with a subsequent increase in the absorption of solar energy. Heat flow modelling shows that, after climatic SAT warming, permanent clearing of the land is the most effective and likely cause of the observed changes in the GST warming. The greater GST warming in the Boreal Forest ecozone in the latter half of this century is related to landscape change due to land development and increasing forest fire activity. It appears to account for a portion of the observed SAT warming in this region through a positive feedback loop with the overlying air. The anthropogenic effect on regional climatic warming through 20th century land clearing and landscape alteration requires further study. In future, more accurate quantification of

  7. Warming spring air temperatures, but delayed spring streamflow in an Arctic headwater basin

    NASA Astrophysics Data System (ADS)

    Shi, Xiaogang; Marsh, Philip; Yang, Daqing

    2015-06-01

    This study will use the Mann-Kendall (MK) non-parametric trend test to examine timing changes in spring (early May to the end of June) streamflow records observed by the Water Survey of Canada during 1985-2011 in an Arctic headwater basin in the Western Canadian Arctic. The MK test shows a general delay in the five timing measures of springtime streamflow, which are based on the 5 percentile (Q5), 10 percentile (Q10), 50 percentile (Q50), 90 percentile (Q90), and 95 percentile (Q95) dates of spring runoff, respectively. However, much stronger trend signals were clearly noted for the high percentiles than that for the low and middle percentiles, indicating different effects of hydroclimate processes working on the timing of springtime streamflow. In contrast, the earlier snowmelt onset derived from daily mean temperatures was found over the 27-year study period. In addition, multiple relationships were correlated between these five timing measures of spring runoff and five hydroclimate indicators (total snowfall, snowmelt onset, spring temperature fluctuation, spring rainfall, and spring rainfall timing) in order to identify possible causes on the changes of springtime streamflow timing. The results indicate that the differences are due to the contradictory effects of winter-spring air temperature changes, temperature fluctuation during the melting period, and spring rainfall to spring runoff. The earlier snowmelt onset, which is attributed to the winter-spring warming, and spring temperature fluctuation that works in the opposite way, result in the minor timing changes of Q5, Q10, and Q50. The increase in spring rainfall and its delayed timing have a significant impact on the dates of Q90 and Q95. Moreover, the decreased total snow accumulation over the winter season only has a minor influence on the timing of springtime streamflow.

  8. Effects of a Circulating-water Garment and Forced-air Warming on Body Heat Content and Core Temperature

    PubMed Central

    Taguchi, Akiko; Ratnaraj, Jebadurai; Kabon, Barbara; Sharma, Neeru; Lenhardt, Rainer; Sessler, Daniel I.

    2005-01-01

    Background: Forced-air warming is sometimes unable to maintain perioperative normothermia. We therefore compared heat transfer, regional heat distribution, and core rewarming of forced-air warming with a novel circulating-water garment. Methods: Nine volunteers were each evaluated on two randomly ordered study days. They were anesthetized and cooled to a core temperature near 34°C. The volunteers were subsequently warmed for 2.5 hours with either a circulating-water garment or forced-air cover. Overall, heat balance was determined from the difference between cutaneous heat loss (thermal flux transducers) and metabolic heat production (oxygen consumption). Average arm and leg (peripheral) tissue temperatures were determined from 18 intramuscular needle thermocouples, 15 skin thermal flux transducers, and “deep” arm and foot thermometers. Results: Heat production (≈ 60 kcal/h) and loss (≈45 kcal/h) were similar with each treatment before warming. The increase in heat transfer across anterior portions of the skin surface was similar with each warming system (≈65 kcal/h). Forced-air warming had no effect on posterior heat transfer whereas circulating-water transferred 21 ± 9 kcal/h through the posterior skin surface after a half hour of warming. Over 2.5 h, circulating-water thus increased body heat content 56% more than forced air. Core temperatures thus increased faster than with circulating water than forced air, especially during the first hour, with the result that core temperature was 1.1 ± 0.7°C greater after 2.5 h (P < 0.001). Peripheral tissue heat content increased twice as much as core heat content with each device, but the core-to-peripheral tissue temperature gradient remained positive throughout the study. Conclusions: The circulating-water system transferred more heat than forced air, with the difference resulting largely from posterior heating. Circulating water rewarmed patients 0.4°C/h faster than forced air. A substantial peripheral

  9. Effect of preoperative forced-air warming on postoperative temperature and postanesthesia care unit length of stay.

    PubMed

    Fettes, Sondra; Mulvaine, Mary; Van Doren, Elaine

    2013-03-01

    Unintended hypothermia in the surgical patient has been linked to numerous postoperative complications, including increased risk for surgical site infection, increased oxygen demands, and altered medication metabolism. The lack of literature on the subject was part of the impetus for perioperative nurses in one hospital to conduct a quality improvement project to evaluate the effectiveness of preoperative warming on patients' postoperative temperatures. We randomly assigned 128 patients to either a group that received a forced-air warming blanket preoperatively or a group that did not. Our results showed that prewarming patients before surgery did not have an effect on patients' postoperative temperatures. PMID:23452697

  10. Modeling 2 m air temperatures over mountain glaciers: Exploring the influence of katabatic cooling and external warming

    NASA Astrophysics Data System (ADS)

    Ayala, A.; Pellicciotti, F.; Shea, J. M.

    2015-04-01

    Air temperature is one of the most relevant input variables for snow and ice melt calculations. However, local meteorological conditions, complex topography, and logistical concerns in glacierized regions make the measuring and modeling of air temperature a difficult task. In this study, we investigate the spatial distribution of 2 m air temperature over mountain glaciers and propose a modification to an existing model to improve its representation. Spatially distributed meteorological data from Haut Glacier d'Arolla (Switzerland), Place (Canada), and Juncal Norte (Chile) Glaciers are used to examine approximate flow line temperatures during their respective ablation seasons. During warm conditions (off-glacier temperatures well above 0°C), observed air temperatures in the upper reaches of Place Glacier and Haut Glacier d'Arolla decrease down glacier along the approximate flow line. At Juncal Norte and Haut Glacier d'Arolla, an increase in air temperature is observed over the glacier tongue. While the temperature behavior over the upper part can be explained by the cooling effect of the glacier surface, the temperature increase over the glacier tongue may be caused by several processes induced by the surrounding warm atmosphere. In order to capture the latter effect, we add an additional term to the Greuell and Böhm (GB) thermodynamic glacier wind model. For high off-glacier temperatures, the modified GB model reduces root-mean-square error up to 32% and provides a new approach for distributing air temperature over mountain glaciers as a function of off-glacier temperatures and approximate glacier flow lines.

  11. Tolerability of Nasal Delivery of Humidified and Warmed Air at Different Temperatures: A Randomised Double-Blind Pilot Study

    PubMed Central

    Bibby, Susan; Reddy, Sumeet; Cripps, Terrianne; McKinstry, Steve; Weatherall, Mark; Beasley, Richard; Pilcher, Janine

    2016-01-01

    Objectives. Delivery of warmed, humidified air via nasal high flow therapy could potentially reduce replication of temperature-sensitive viruses in the upper respiratory tract. This study investigates whether nasal high flow therapy is well tolerated by healthy adults at 37°C and 41°C. Methods. In this randomised, double-blind, controlled crossover pilot trial, nasal high flow therapy was used to deliver humidified air at 35 L/min, at either 37°C or 41°C, for three one-hour sessions of use over one day. The alternative was delivered at least 14 days later. Ten healthy, nonsmoking adults were asked, via questionnaire after each day's use, whether they would use nasal high flow therapy while being unwell with a cold or flu if it was demonstrated to improve symptoms. Results. All participants completed both interventions. Eighty percent responded “yes” to future use of nasal high flow therapy, for both 37°C and 41°C. There was no significant change from baseline in saccharin times following either intervention or in the following morning. Conclusions. Delivering humidified air via nasal high flow therapy at both 37°C and 41°C is well tolerated by healthy adults. This supports investigation into the potential use of nasal high flow therapy as treatment in viral upper respiratory tract infections. Trial Registration. This trial is registered with ACTRN12614000183684 (tolerability study of nasal delivery of humidified & warmed air). PMID:27127650

  12. Effects of Full-Season Temperature Free-Air-Controlled Enhancement (T-FACE) Ecosystem Warming on Leaf Number

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global warming is likely to affect crop canopy development. However, our ability to quantitatively predict how temperature affects processes such as leaf appearance rates still requires refinement. Although controlled-environment chambers can be used to study temperature responses, they introduce nu...

  13. Water Consumption, Soil Temperature and Soil Respiration in Model Ecosystems of Young Oak Stands Treated by Air-warming and Drought

    NASA Astrophysics Data System (ADS)

    Kuster, Thomas; Arend, Matthias; Günthardt-Goerg, Madeleine S.; Schulin, Rainer

    2010-05-01

    IPCC scenarios predict a global mean annual temperature increase during the 21st century of 2 - 6 °C, as well as changes in precipitation patterns. The multidisciplinary project "Querco" addresses the question how increased air temperature and extended drought periods will influence stands of young oaks. For this purpose, mixed stands of young Q. robur, Q. pubescens and Q. petrea (4-year-old trees from seeds of four different provenances each) were composed in the WSL open-top model-ecosystem chambers on either acid or calcareous forest soils and grown under four different climate treatments (control, air-warming, drought, air-warming & drought) from 2007 to 2009. Drought treated chambers only received about one third of water during the growing seasons from May to October as compared to the control. Further, we established longer drought periods without any irrigation. The air-warming treatment was established by keeping the side walls of the open-top chambers more closed than in the controls. Unsurprisingly, evapotranspiration from dry soils was much lower than from irrigated soils. There was significantly more evapotranspiration from the acidic than from the calcareous soil. These findings are in line with increased leaf transpiration rates and a tendency towards higher leaf biomass in oaks growing on acid as compared to calcareous soil. The higher evapotranspiration from acid soils also was in line with the fact that soil water potentials decreased more in acidic than in calcareous soils, an effect that became particularly significant during periods of high consumptive water demand by the trees. While soil water potentials were strongly decreased by the drought treatments down to 1 m depth, the air-warming treatment had almost no effect on soil water potential. Treatments, air-warming and drought, significantly increased soil temperature. In drought treated soils, this effect was related to the lower water content as compared to the control soils. As intended

  14. Temperature Data Shows Warming in 2001

    NASA Technical Reports Server (NTRS)

    2002-01-01

    TThe figure above depicts how much air temperatures near the Earth's surface changed relative to the global mean temperature from 1951 to 1980. NASA researchers used maps of urban areas derived from city lights data to account for the 'heat island' effect of cities. The red and orange colors show that temperatures are warmer in most regions of the world when compared to the 1951 to 1980 'normal' temperatures. Warming around the world has been widespread, but it is not present everywhere. The largest warming is in Northern Canada, Alaska and Siberia, as indicated by the deeper red colors. The lower 48 United States have become warmer recently, but only enough to make the temperatures comparable to what they were in the 1930s. The scale on the bottom of these temperature anomaly images represent degrees in Celsius. The negative numbers represent cooling and the positive numbers depict warming. Overall, the air temperature near the Earth's surface has warmed by 1oF (0.6oC) globally, on average, over the last century. For more information and additional images, read Satellites Shed Light on a Warmer World. Image courtesy Goddard Institute for Space Studies (GISS).

  15. Effects of warming on uptake and translocation of cadmium (Cd) and copper (Cu) in a contaminated soil-rice system under Free Air Temperature Increase (FATI).

    PubMed

    Ge, Li-Qiang; Cang, Long; Liu, Hui; Zhou, Dong-Mei

    2016-07-01

    Global warming has received growing attentions about its potential threats to human in recent, however little is known about its effects on transfer of heavy metals in agro-ecosystem, especially for Cd in rice. Pot experiments were conducted to evaluate Cd/Cu translocation in a contaminated soil-rice system under Free Air Temperature Increase (FATI). The results showed that warming gradually decreased soil porewater pH and increased water-soluble Cd/Cu concentration, reduced formation of iron plaque on root surface, and thus significantly increased total uptake of Cd/Cu by rice. Subsequently, warming significantly promoted Cd translocation from root to shoot, and increased Cd distribution percentage in shoot, while Cu was not significantly affected. Enhanced Cd uptake and translocation synergistically resulted in higher rice grain contamination with increasing concentration from 0.27 to 0.65 and 0.14-0.40 mg kg(-1) for Indica and Japonica rice, respectively. However increase of Cu in brown grain was only attributed to its uptake enhancement under warming. Our study provides a new understanding about the food production insecurity of heavy metal contaminated soil under the future global warming. PMID:27093634

  16. Causality of global warming seen from observations: a scale analysis of driving force of the surface air temperature time series in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Yang, Peicai; Wang, Geli; Zhang, Feng; Zhou, Xiuji

    2016-05-01

    By using the slow feature analysis, we reconstructed the driving force for an observed monthly surface air temperature anomaly time series in the northern hemisphere. Wavelet transformation technique was then used to analyze the scale structure of the derived driving force and its causal relationship with global warming. Results showed that the driving force for the analyzed temperature climate system included two independent degrees of freedom which respectively represented the effects of 22-year solar cycle and Atlantic Multidecadal Oscillation on the climate. More importantly, the driving force is modulated in amplitude by signals with much longer time periods. The modulation controls the energy input to the climate system and its effect on the global warming is decisive. In addition, through analyzing phase transitions from zero to extremes of the modulating signals, we provide a projection for the future trend of the surface air temperature. In specific, in the next 45-65 years, the driving force will continue to rise which will drive the air temperature even warmer. This is a long term natural trend determined by the modulating amplitude signals, but not directly related to human activity.

  17. The effect of preoperative warming on patients' postoperative temperatures.

    PubMed

    Cooper, Shauna

    2006-05-01

    Many perioperative clinicians encounter difficulty in preventing hypothermia in surgical patients. One intervention to prevent perioperative hypothermia is the use of forced-air warming. Although forced-air warming is used most frequently in the intraoperative area, prewarming patients with forced-air warming systems before induction of anesthesia may be enough to prevent hypothermia throughout the surgical procedure, allowing patients to arrive in the postanesthesia care unit in a normothermic state. A review of the literature on preoperative forced-air warming is provided, and the effect of prewarming on postoperative patient temperatures is discussed. PMID:16722285

  18. Chamberless residential warm air furnace design

    SciTech Connect

    Godfree, J.

    1996-07-01

    This brief paper is an introduction to the concept of designing residential warm air furnaces without combustion chambers. This is possible since some small burners do not require the thermal support of a combustion chamber to complete the combustion process.

  19. Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

    PubMed Central

    Amos-Abanyie, S.; Akuffo, F. O.; Kutin-Sanwu, V.

    2013-01-01

    Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+) simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT). An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses. PMID:23878528

  20. Comparison of the efficacy of a forced-air warming system and circulating-water mattress on core temperature and post-anesthesia shivering in elderly patients undergoing total knee arthroplasty under spinal anesthesia

    PubMed Central

    Lee, Kyu Chang; Lee, Myeong Jong; Kim, Mi-Na; Kim, Ji-Sub; Lee, Won Sang; Lee, Jung Hwa

    2014-01-01

    Background In the present study, we compared changes in body temperature and the occurrence of shivering in elderly patients undergoing total knee arthroplasty under spinal anesthesia during warming with either a forced-air warming system or a circulating-water mattress. Methods Forty-six patients were randomly assigned to either the forced-air warming system (N = 23) or circulating-water mattress (N = 23) group. Core temperature was recorded using measurements at the tympanic membrane and rectum. In addition, the incidence and intensity of post-anesthesia shivering and verbal analogue score for thermal comfort were simultaneously assessed. Results Core temperature outcomes did not differ between the groups. The incidence (13.0 vs 43.5%, P < 0.05) and intensity (20/2/1/0/0 vs 13/5/3/2/0, P < 0.05) of post-anesthesia shivering was significantly lower in the forced-air system group than in the circulating-water mattress group. Conclusions The circulating-water mattress was as effective as the forced-air warming system for maintaining body temperature. However, the forced-air warming system was superior to the circulating-water mattress in reducing the incidence of post-anesthesia shivering. PMID:24910726

  1. Forced-air patient warming blankets disrupt unidirectional airflow.

    PubMed

    Legg, A J; Hamer, A J

    2013-03-01

    We have recently shown that waste heat from forced-air warming blankets can increase the temperature and concentration of airborne particles over the surgical site. The mechanism for the increased concentration of particles and their site of origin remained unclear. We therefore attempted to visualise the airflow in theatre over a simulated total knee replacement using neutral-buoyancy helium bubbles. Particles were created using a Rocket PS23 smoke machine positioned below the operating table, a potential area of contamination. The same theatre set-up, warming devices and controls were used as in our previous study. This demonstrated that waste heat from the poorly insulated forced-air warming blanket increased the air temperature on the surgical side of the drape by > 5°C. This created convection currents that rose against the downward unidirectional airflow, causing turbulence over the patient. The convection currents increased the particle concentration 1000-fold (2 174 000 particles/m(3) for forced-air warming vs 1000 particles/m(3) for radiant warming and 2000 particles/m(3) for the control) by drawing potentially contaminated particles from below the operating table into the surgical site. Cite this article: Bone Joint J 2013;95-B:407-10. PMID:23450029

  2. Warm-air advection, air mass transformation and fog causes rapid ice melt

    NASA Astrophysics Data System (ADS)

    Tjernström, Michael; Shupe, Matthew D.; Brooks, Ian M.; Persson, P. Ola G.; Prytherch, John; Salisbury, Dominic J.; Sedlar, Joseph; Achtert, Peggy; Brooks, Barbara J.; Johnston, Paul E.; Sotiropoulou, Georgia; Wolfe, Dan

    2015-07-01

    Direct observations during intense warm-air advection over the East Siberian Sea reveal a period of rapid sea-ice melt. A semistationary, high-pressure system north of the Bering Strait forced northward advection of warm, moist air from the continent. Air-mass transformation over melting sea ice formed a strong, surface-based temperature inversion in which dense fog formed. This induced a positive net longwave radiation at the surface while reducing net solar radiation only marginally; the inversion also resulted in downward turbulent heat flux. The sum of these processes enhanced the surface energy flux by an average of ~15 W m-2 for a week. Satellite images before and after the episode show sea-ice concentrations decreasing from > 90% to ~50% over a large area affected by the air-mass transformation. We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm-air advection.

  3. Air-cooled CWS warm air furnace. Final report

    SciTech Connect

    Litka, A.F.; Becker, F.E.

    1995-08-01

    Thermo Power Corporation, Tecogen Division, has developed coal water slurry (CWS) combustion technologies specifically tailored to meet the space heating needs of the residential, commercial, and industrial market sectors. This furnace was extensively tested and met all the design and operating criteria of the development program, which included combustion efficiencies in excess of 99%, response to full load from a cold start in less than 5 minutes, and steady-state thermal efficiencies as high as 85%. While this furnace design is extremely versatile, versatility came at the expense of system complexity and cost. To provide a more cost effective CWS-based option for the residential market sector, Tecogen, developed a totally air-cooled CWS-fired residential warm air heating system. To minimize system cost and to take advantage of industry manufacturing practices and experience, a commercially available oil/gas solid fuel-fired central furnace, manufactured by Yukon Energy Corporation, was used as the platform for the CWS combustor and related equipment. A prototype furnace was designed, built, and tested in the laboratory to verify system integrity and operation. This unit was then shipped to the PETC to undergo demonstration operation and serve as a showcase of the CWS technology. An in-depth Owners Manual was prepared and delivered with the furnace. This Owners Manual, which is included as Appendix A of this report, includes installation instructions, operating procedures, wiring diagrams, and equipment bulletins on the major components. It also contains coal water slurry fuel specifications and typical system operating variables, including key temperatures, pressures, and flowrates.

  4. Global Warming and Air Quality in China

    NASA Astrophysics Data System (ADS)

    Liu, S. C.

    2014-12-01

    The atmospheric lapse rate has been observed to decrease as a result of global warming. Reduced lapse rate is a result of a robust water vapor/lapse rate climate feedback simulated in coupled ocean-atmosphere models. The reduced lapse rate makes the atmosphere more stable, and in turn the more stable atmosphere can affect air quality in many aspects, most of them detrimental to the air quality. The largest effect of an increased vertical stability is an increased trapping of air pollutants in the boundary layer. A more stable atmosphere also makes it less likely to precipitate, especially for light and moderate precipitation that requires an unstable large-scale environment. Thus there is less scavenging of air pollutants by precipitation. Furthermore less precipitation implies less cloud cover or more clear days which can result in more nighttime inversions, again trapping more pollutants in the surface layer. Significant increase in clear days has been observed in China in the last 50 years, this can be a major contributor to more and worse fog/haze events in recent decades.

  5. Global temperatures and the global warming ``debate''

    NASA Astrophysics Data System (ADS)

    Aubrecht, Gordon

    2009-04-01

    Many ordinary citizens listen to pronouncements on talk radio casting doubt on anthropogenic global warming. Some op-ed columnists likewise cast doubts, and are read by credulous citizens. For example, on 8 March 2009, the Boston Globe published a column by Jeff Jacoby, ``Where's global warming?'' According to Jacoby, ``But it isn't such hints of a planetary warming trend that have been piling up in profusion lately. Just the opposite.'' He goes on to write, ``the science of climate change is not nearly as important as the religion of climate change,'' and blamed Al Gore for getting his mistaken views accepted. George Will at the Washington Post also expressed denial. As a result, 44% of U.S. voters, according to the January 19 2009 Rasmussen Report, blame long-term planetary trends for global warming, not human beings. Is there global cooling, as skeptics claim? We examine the temperature record.

  6. Stream Temperature Sensitivity to Climate Warming in California's Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Null, S.; Viers, J. H.; Deas, M.; Tanaka, S.; Mount, J.

    2010-12-01

    Water temperatures influence the distribution, abundance, and health of aquatic organisms in stream ecosystems. Improving understanding of climate warming on the thermal regime of rivers will help water managers better manage instream habitat. This study assesses climate warming impacts on unregulated stream temperatures in California’s west-slope Sierra Nevada watersheds from the Feather River to the Kern River. We used unregulated hydrology to isolate climate induced changes from those of water operations and land use changes. A 21 year timeseries of weekly instream flow estimates from WEAP21, a spatially explicit rainfall-runoff model were passed to RTEMP, a simplified model based on equilibrium temperature theory, to estimate stream temperatures using net heat exchange, coarse river channel geometry, and exposure time of water to atmospheric conditions. Air temperature was uniformly increased by 2○C, 4○C, and 6○C as a sensitivity analysis to bracket the range of likely outcomes for stream temperatures. Other meteorological conditions, including precipitation, were left unchanged from historical values. Overall, stream temperatures increased by an average of 1.6○C for each 2○C rise in air temperature, and increased most at middle elevations. Thermal heterogeneity existed within and between basins (Figure 1). The high watersheds of the southern Sierra Nevada and the Feather River watershed were less vulnerable to changes in the thermal regime of rivers from climate warming. Precipitation as rainfall instead of snowfall, and low flow conditions were two characteristics that drove water temperatures dynamics with climate warming. These results suggest the thermal regime of rivers will change with climate warming. Viable coldwater habitat will shift to higher elevations and will likely be reduced in California. Understanding potential changes to stream temperatures from climate warming will affect how fish and wildlife are managed, and must be

  7. Do forced air patient-warming devices disrupt unidirectional downward airflow?

    PubMed

    Legg, A J; Cannon, T; Hamer, A J

    2012-02-01

    Patient warming significantly decreases the risk of surgical site infection. Recently there have been concerns that forced air warming may interfere with unidirectional airflow, potentially posing an increased risk of infection. Our null hypothesis was that forced air and radiant warming devices do not increase the temperature and the number of particles over the surgical site when compared with no warming device. A forced air warming device was compared with a radiant warming device and no warming device as a control. The temperature and number of particles were measured over the surgical site. The theatre was prepared as for a routine lower-limb arthroplasty operation, and the same volunteer was used throughout the study. Forced air warming resulted in a significant mean increase in the temperature (1.1°C vs 0.4°C, p < 0.0001) and number of particles (1038.2 vs 274.8, p = 0.0087) over the surgical site when compared with radiant warming, which raises concern as bacteria are known to require particles for transport. PMID:22323696

  8. Preoperative forced-air warming combined with intraoperative warming versus intraoperative warming alone in the prevention of hypothermia during gynecologic surgery.

    PubMed

    Adriani, Melissa Bucci; Moriber, Nancy

    2013-12-01

    Hypothermia in the perioperative setting can have serious consequences, including increased risk of infection or adverse cardiac events. Forced-air warming units commonly are used to prevent hypothermia. This study examined the impact of adding preoperative warming (Bair Paws, 3M) to conventional intraoperative forced-air warming modalities. Thirty patients received both preoperative and intraoperative forced-air warming, and 30 patients received intraoperative warming alone. Temperature readings were recorded across 3 time periods: preoperative, intraoperative, and postoperative. Data were analyzed using descriptive statistics, analysis of variance (ANOVA), and repeated-measures ANOVA. Demographics were similar in both groups with respect to age, body mass index, total intravenous fluids, and estimated blood loss. Statistically significant differences in temperature were seen over time (df = 2, P < .001), and for each intervention across all 3 time periods (P = .042). However, no statistically significant differences in temperature were demonstrated between groups over time. ASA status and type of procedure (laparoscopic vs open) also had no impact on results. These results suggest that preoperative warming with the Bair Paws gown offers no benefit over conventional therapy in maintaining normothermia in the perioperative period. PMID:24597006

  9. Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods.

    PubMed

    Bransburg-Zabary, Sharron; Virozub, Alexander; Mimouni, Francis B

    2015-01-01

    Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60 ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast. PMID:26061694

  10. Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods

    PubMed Central

    Bransburg-Zabary, Sharron; Virozub, Alexander; Mimouni, Francis B.

    2015-01-01

    Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast. PMID:26061694

  11. Microclimatic performance of a free-air warming and CO₂ enrichment experiment in windy Wyoming, USA

    SciTech Connect

    LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco; Liang, Wenju

    2015-02-06

    In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO₂ had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much

  12. Microclimatic performance of a free-air warming and CO₂ enrichment experiment in windy Wyoming, USA

    DOE PAGESBeta

    LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco; Liang, Wenju

    2015-02-06

    In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night)more » but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO₂ had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming

  13. Tree canopy temperature response under experimental warming and drought

    NASA Astrophysics Data System (ADS)

    Blair, S. N.; Garrity, S. R.; Cai, M.; McDowell, N. G.

    2012-12-01

    Tree mortality associated with rising temperatures and drought has been observed in numerous locations across the globe. Simulated global climate change experiments, such as increased air temperature and reduced precipitation, can help us understand tree response to altered climate regimes and identify key physiological mechanisms involved in tree stress response. We collected canopy-level leaf temperature measurements from several piñon (Pinus edulis) and one-seed juniper (juniperus monosperma) subjected to experimental warming, drought, combined warming and drought treatments, and control conditions in a field-based experiment in northern New Mexico beginning June 2012. We examined leaf temperature responses to the treatments by using continuous measurements from infrared thermocouples located above the tree canopy. We found that leaf temperatures were approximately 5 degrees warmer in heated chambers compared to leaf temperatures of trees outside chambers. Comparisons within each treatment demonstrated that, on average, piñon had higher absolute differences between leaf temperature and air temperature values compared to juniper trees. Stomatal conductance, measured with a leaf porometer showed that within each treatment, juniper had higher stomatal conductance relative to piñon, and that heated trees had lower stomatal conductance relative to non-heated trees. These differences may be attributable to the fact that piñon trees are isohydric, meaning that they have a lower tolerance to water stress. To date, we have not observed a significant drought effect on leaf temperature, however, this is likely due to the short duration of the drought treatment to date. We expect that as the experiment progresses, a drought effect will emerge. One of the key questions that we hope to answer as data continues to be collected is how tree physiology responds to drought, heat, and the interaction between both variables. Although this case study is being conducted in

  14. Temperature and size variabilities of the Western Pacific Warm Pool

    NASA Technical Reports Server (NTRS)

    Yan, Xiao-Hai; Ho, Chung-Ru; Zheng, Quanan; Klemas, Vic

    1992-01-01

    Variabilities in sea-surface temperature and size of the Western Pacific Warm Pool were tracked with 10 years of satellite multichannel sea-surface temperature observations from 1982 to 1991. The results show that both annual mean sea-surface temperature and the size of the warm pool increased from 1983 to 1987 and fluctuated after 1987. Possible causes of these variations include solar irradiance variabilities, El Nino-Southern Oscillaton events, volcanic activities, and global warming.

  15. Warm air sensation for assessment of block after spinal anaesthesia.

    PubMed

    Shah, J; Ayorinde, B T; Rowbotham, D J; Buggy, D J

    2000-03-01

    We have evaluated a new method of assessing dermatomal sensory levels after regional anaesthesia based on warm sensation. Sensory levels were assessed in 30 patients after spinal anaesthesia using a respiratory gas humidifier, adapted to deliver a constant flow of warm air at 40 +/- 0.2 degrees C. This was compared with the cold sensation from ethyl chloride spray. The frequency distribution of the dermatomal differences showed 96.6% of the comparisons were between +1 and -1 dermatomes. The median difference in dermatomal levels between the two methods of assessment was 0 (interquartile range 0-1) (P = 0.65). We conclude that the warm air method compares favourably with ethyl chloride spray and both can be used interchangeably. PMID:10793604

  16. Low clouds suppress Arctic air formation and amplify high-latitude continental winter warming

    PubMed Central

    Cronin, Timothy W.; Tziperman, Eli

    2015-01-01

    High-latitude continents have warmed much more rapidly in recent decades than the rest of the globe, especially in winter, and the maintenance of warm, frost-free conditions in continental interiors in winter has been a long-standing problem of past equable climates. We use an idealized single-column atmospheric model across a range of conditions to study the polar night process of air mass transformation from high-latitude maritime air, with a prescribed initial temperature profile, to much colder high-latitude continental air. We find that a low-cloud feedback—consisting of a robust increase in the duration of optically thick liquid clouds with warming of the initial state—slows radiative cooling of the surface and amplifies continental warming. This low-cloud feedback increases the continental surface air temperature by roughly two degrees for each degree increase of the initial maritime surface air temperature, effectively suppressing Arctic air formation. The time it takes for the surface air temperature to drop below freezing increases nonlinearly to ∼10 d for initial maritime surface air temperatures of 20 °C. These results, supplemented by an analysis of Coupled Model Intercomparison Project phase 5 climate model runs that shows large increases in cloud water path and surface cloud longwave forcing in warmer climates, suggest that the “lapse rate feedback” in simulations of anthropogenic climate change may be related to the influence of low clouds on the stratification of the lower troposphere. The results also indicate that optically thick stratus cloud decks could help to maintain frost-free winter continental interiors in equable climates. PMID:26324919

  17. Low clouds suppress Arctic air formation and amplify high-latitude continental winter warming.

    PubMed

    Cronin, Timothy W; Tziperman, Eli

    2015-09-15

    High-latitude continents have warmed much more rapidly in recent decades than the rest of the globe, especially in winter, and the maintenance of warm, frost-free conditions in continental interiors in winter has been a long-standing problem of past equable climates. We use an idealized single-column atmospheric model across a range of conditions to study the polar night process of air mass transformation from high-latitude maritime air, with a prescribed initial temperature profile, to much colder high-latitude continental air. We find that a low-cloud feedback--consisting of a robust increase in the duration of optically thick liquid clouds with warming of the initial state--slows radiative cooling of the surface and amplifies continental warming. This low-cloud feedback increases the continental surface air temperature by roughly two degrees for each degree increase of the initial maritime surface air temperature, effectively suppressing Arctic air formation. The time it takes for the surface air temperature to drop below freezing increases nonlinearly to ∼ 10 d for initial maritime surface air temperatures of 20 °C. These results, supplemented by an analysis of Coupled Model Intercomparison Project phase 5 climate model runs that shows large increases in cloud water path and surface cloud longwave forcing in warmer climates, suggest that the "lapse rate feedback" in simulations of anthropogenic climate change may be related to the influence of low clouds on the stratification of the lower troposphere. The results also indicate that optically thick stratus cloud decks could help to maintain frost-free winter continental interiors in equable climates. PMID:26324919

  18. D-0 End Calorimeter Warm Tube/TeV Dry Air Purge

    SciTech Connect

    Leibfritz, J.R.; /Fermilab

    1991-08-14

    This Engineering Note studies the design of the Dry Air Purge that is going to flow through the Warm Tube of the End Calorimeter of the D-O Calorimeter. The Tev tubes through the E.C. can be thought of as a cluster of concentric tubes: The Tev tube, the warm (vacuum vessel) tube, 15 layers of superinsulation, the cold (argon vessel) tube, and the Inner Hadronic center support tube. The Dry Air Purge will involve flowing Dry Air through the annular region between the Warm Tube and the Tev Beam Pipe. This air flow is intended to prevent condensation from forming in this region which could turn to ice under cryogenic temperatures. Any ice formed in this gap, could cause serious problems when these tubes are moved. The Air will flow through a Nylon Tube Fitting -1/4-inch I.D. to 1/8-inch male pipe thread (Cole Palmer YB-06465-15) see Drawing MC-295221 (Appendix A). This fitting will be attached to the Nylon 2-inch Tube-Wiper and Seal Assembly which is clamped to the ends of the Warm Tube (Appendix A). This note includes drawings and calculations that explain the setup of the Dry Air Purge and give the required information on the pressure drops through the setup. The Equations and properties used in the calculations were obtained from the Applied Fluid Dynamics Handbook by Robert D. Blevins and Fluid Dynamics Second Edition by Frank M. White.

  19. Role of radiatively forced temperature changes in enhanced semi-arid warming over East Asia

    NASA Astrophysics Data System (ADS)

    Guan, X.; Huang, J.; Guo, R.; Lin, P.; Zhang, Y.

    2015-08-01

    As the climate change occurred over East Asia since 1950s, intense interest and debate have arisen concerning the contribution of human activities to the warming observed in previous decades. In this study, we investigate surface temperature change using a recently developed methodology that can successfully identify and separate the dynamically induced temperature (DIT) and radiatively forced temperature (RFT) changes in raw surface air temperature (SAT) data. For regional averages, DIT and RFT make 43.7 and 56.3 % contributions to the SAT over East Asia, respectively. The DIT changes dominate the SAT decadal variability and are mainly determined by internal climate variability, such as the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO). The radiatively forced SAT changes made major contribution to the global-scale warming trend and the regional-scale enhanced semi-arid warming (ESAW). Such enhanced warming is also found in radiatively forced daily maximum and minimum SAT. The long-term global-mean SAT warming trend is mainly related to radiative forcing produced by global well-mixed greenhouse gases. The regional anthropogenic radiative forcing, however, caused the enhanced warming in the semi-arid region, which may be closely associated with local human activities. Finally, the relationship between global warming hiatus and regional enhanced warming is discussed.

  20. Optimal Detection of Global Warming using Temperature Profiles

    NASA Technical Reports Server (NTRS)

    Leroy, Stephen S.

    1997-01-01

    Optimal fingerprinting is applied to estimate the amount of time it would take to detect warming by increased concentrations of carbon dioxide in monthly averages of temperature profiles over the Indian Ocean.

  1. Unabated global surface temperature warming: evaluating the evidence

    NASA Astrophysics Data System (ADS)

    Karl, T. R.; Arguez, A.

    2015-12-01

    New insights related to time-dependent bias corrections in global surface temperatures have led to higher rates of warming over the past few decades than previously reported in the IPCC Fifth Assessment Report (2014). Record high global temperatures in the past few years have also contributed to larger trends. The combination of these factors and new analyses of the rate of temperature change show unabated global warming since at least the mid-Twentieth Century. New time-dependent bias corrections account for: (1) differences in temperatures measured from ships and drifting buoys; (2) improved corrections to ship measured temperatures; and (3) the larger rates of warming in polar regions (particularly the Arctic). Since 1951, the period over which IPCC (2014) attributes over half of the observed global warming to human causes, it is shown that there has been a remarkably robust and sustained warming, punctuated with inter-annual and decadal variability. This finding is confirmed through simple trend analysis and Empirical Mode Decomposition (EMD). Trend analysis however, especially for decadal trends, is sensitive to selection bias of beginning and ending dates. EMD has no selection bias. Additionally, it can highlight both short- and long-term processes affecting the global temperature times series since it addresses both non-linear and non-stationary processes. For the new NOAA global temperature data set, our analyses do not support the notion of a hiatus or slowing of long-term global warming. However, sub-decadal periods of little (or no warming) and rapid warming can also be found, clearly showing the impact of inter-annual and decadal variability that previously has been attributed to both natural and human-induced non-greenhouse forcings.

  2. Evaluation of low temperature properties of warm mix asphalt

    NASA Astrophysics Data System (ADS)

    Wen, Jin; Liu, Zhifei; Wu, Shaopeng

    2010-03-01

    Warm mix asphalt (WMA), which reduces the mixing and compaction temperature of conventional hot mix asphalt (HMA), is becoming an attractive paving material. It is critical to identify the low temperature properties of warm mix asphalt. In this study, the three-point bending, bending creep tests and indirect tensile tests were conducted to test the low-temperature properties of warm mix asphalt as well as the conventional hot mix asphalt, which was used as the control mixture. Sasobit and Aspha-min were used as additives for warm mix asphalt, which was mixed and compacted lower than the traditional hot mix asphalt about 25°C dosages accounted for 3% of asphalt, and 0.3% of mixture, respectively. The results of bending strength, bending modulus, and creep rate indicate that warm mix asphalt using Sasobit and Aspha-min slightly affects the resistance property to cracking compared with the conventional hot mix asphalt. The results suggest that the warm mix asphalt can maintain the low temperature properties of hot mix asphalt.

  3. Evaluation of low temperature properties of warm mix asphalt

    NASA Astrophysics Data System (ADS)

    Wen, Jin; Liu, Zhifei; Wu, Shaopeng

    2009-12-01

    Warm mix asphalt (WMA), which reduces the mixing and compaction temperature of conventional hot mix asphalt (HMA), is becoming an attractive paving material. It is critical to identify the low temperature properties of warm mix asphalt. In this study, the three-point bending, bending creep tests and indirect tensile tests were conducted to test the low-temperature properties of warm mix asphalt as well as the conventional hot mix asphalt, which was used as the control mixture. Sasobit and Aspha-min were used as additives for warm mix asphalt, which was mixed and compacted lower than the traditional hot mix asphalt about 25°C dosages accounted for 3% of asphalt, and 0.3% of mixture, respectively. The results of bending strength, bending modulus, and creep rate indicate that warm mix asphalt using Sasobit and Aspha-min slightly affects the resistance property to cracking compared with the conventional hot mix asphalt. The results suggest that the warm mix asphalt can maintain the low temperature properties of hot mix asphalt.

  4. Electron-ion temperature equilibration in warm dense tantalum

    DOE PAGESBeta

    Doppner, T; LePape, S.; Ma, T.; Pak, A.; Hartley, N. J.; Peters, L.; Gregori, G.; Belancourt, P.; Drake, R. P.; Chapman, D. A.; et al

    2014-11-05

    We present measurements of electron-ion temperature equilibration in proton-heated tantalum, under warm dense matter conditions. Our results agree with theoretical predictions for metals calculated using input data from ab initio simulations. Furthermore, the fast relaxation observed in the experiment contrasts with much longer equilibration times found in proton heated carbon, indicating that the energy flow pathways in warm dense matter are far from being fully understood.

  5. Electron-ion temperature equilibration in warm dense tantalum

    SciTech Connect

    Doppner, T; LePape, S.; Ma, T.; Pak, A.; Hartley, N. J.; Peters, L.; Gregori, G.; Belancourt, P.; Drake, R. P.; Chapman, D. A.; Richardson, S.; Gericke, D. O.; Glenzer, S. H.; Khaghani, D.; Neumayer, P.; Vorberger, J.; White, T. G.

    2014-11-05

    We present measurements of electron-ion temperature equilibration in proton-heated tantalum, under warm dense matter conditions. Our results agree with theoretical predictions for metals calculated using input data from ab initio simulations. Furthermore, the fast relaxation observed in the experiment contrasts with much longer equilibration times found in proton heated carbon, indicating that the energy flow pathways in warm dense matter are far from being fully understood.

  6. Spatiotemporal Divergence of the Warming Hiatus over Land Based on Different Definitions of Mean Temperature.

    PubMed

    Zhou, Chunlüe; Wang, Kaicun

    2016-01-01

    Existing studies of the recent warming hiatus over land are primarily based on the average of daily minimum and maximum temperatures (T2). This study compared regional warming rates of mean temperature based on T2 and T24 calculated from hourly observations available from 1998 to 2013. Both T2 and T24 show that the warming hiatus over land is apparent in the mid-latitudes of North America and Eurasia, especially in cold seasons, which is closely associated with the negative North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) and cold air propagation by the Arctic-original northerly wind anomaly into mid-latitudes. However, the warming rates of T2 and T24 are significantly different at regional and seasonal scales because T2 only samples air temperature twice daily and cannot accurately reflect land-atmosphere and incoming radiation variations in the temperature diurnal cycle. The trend has a standard deviation of 0.43 °C/decade for T2 and 0.41 °C/decade for T24, and 0.38 °C/decade for their trend difference in 5° × 5° grids. The use of T2 amplifies the regional contrasts of the warming rate, i.e., the trend underestimation in the US and overestimation at high latitudes by T2. PMID:27531421

  7. Spatiotemporal Divergence of the Warming Hiatus over Land Based on Different Definitions of Mean Temperature

    PubMed Central

    Zhou, Chunlüe; Wang, Kaicun

    2016-01-01

    Existing studies of the recent warming hiatus over land are primarily based on the average of daily minimum and maximum temperatures (T2). This study compared regional warming rates of mean temperature based on T2 and T24 calculated from hourly observations available from 1998 to 2013. Both T2 and T24 show that the warming hiatus over land is apparent in the mid-latitudes of North America and Eurasia, especially in cold seasons, which is closely associated with the negative North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) and cold air propagation by the Arctic-original northerly wind anomaly into mid-latitudes. However, the warming rates of T2 and T24 are significantly different at regional and seasonal scales because T2 only samples air temperature twice daily and cannot accurately reflect land-atmosphere and incoming radiation variations in the temperature diurnal cycle. The trend has a standard deviation of 0.43 °C/decade for T2 and 0.41 °C/decade for T24, and 0.38 °C/decade for their trend difference in 5° × 5° grids. The use of T2 amplifies the regional contrasts of the warming rate, i.e., the trend underestimation in the US and overestimation at high latitudes by T2. PMID:27531421

  8. Daily Temperature Records in a Warming Climate

    NASA Astrophysics Data System (ADS)

    Meehl, G. A.; Tebaldi, C.

    2014-12-01

    The ratio of daily record high maximum temperatures to daily record low minimum temperatures in the first decade of the 21st century was about 2 to 1. Previous model simulations also showed a comparable ratio, with projections of an increase in that ratio in the 21st century. Here we relate record highs and record lows to changing surface conditions in 1 degree and 0.5 degree resolution global coupled climate models for 20th and 21st century climate to address the issue of model resolution in simulating past and future changes of temperature extremes as represented by daily record highs and lows.

  9. Microclimatic Performance of a Free-Air Warming and CO2 Enrichment Experiment in Windy Wyoming, USA

    PubMed Central

    LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco

    2015-01-01

    In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO2) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO2 enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms-1 average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO2 had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO2. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much of the

  10. Air-activated chemical warming devices: effects of oxygen and pressure.

    PubMed

    Raleigh, G; Rivard, R; Fabus, S

    2005-01-01

    Air-activated chemical warming devices use an exothermic chemical reaction of rapidly oxidizing iron to generate heat for therapeutic purposes. Placing these products in a hyperbaric oxygen environment greatly increases the supply of oxidant and thus increases the rate of reaction and maximum temperature. Testing for auto-ignition and maximum temperatures attained by ThermaCare Heat Wraps, Playtex Heat Therapy, and Heat Factory disposable warm packs under ambient conditions and under conditions similar to those encountered during hyperbaric oxygen treatments in monoplace and multiplace hyperbaric chambers (3 atm abs and > 95% oxygen) revealed a maximum temperature of 269 degrees F (132 degrees C) with no spontaneous ignition. The risk of thermal burn injury to adjacent skin may be increased significantly if these devices are used under conditions of hyperbaric oxygen. PMID:16509287

  11. Contribution of air conditioning adoption to future energy use under global warming.

    PubMed

    Davis, Lucas W; Gertler, Paul J

    2015-05-12

    As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change. PMID:25918391

  12. Contribution of air conditioning adoption to future energy use under global warming

    PubMed Central

    Davis, Lucas W.; Gertler, Paul J.

    2015-01-01

    As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change. PMID:25918391

  13. A Phenological Timetable of Oak Growth under Experimental Drought and Air Warming

    PubMed Central

    Kuster, Thomas M.; Dobbertin, Matthias; Günthardt-Goerg, Madeleine S.; Schaub, Marcus; Arend, Matthias

    2014-01-01

    Climate change is expected to increase temperature and decrease summer precipitation in Central Europe. Little is known about how warming and drought will affect phenological patterns of oaks, which are considered to possess excellent adaptability to these climatic changes. Here, we investigated bud burst and intra-annual shoot growth of Quercus robur, Q. petraea and Q. pubescens grown on two different forest soils and exposed to air warming and drought. Phenological development was assessed over the course of three growing seasons. Warming advanced bud burst by 1–3 days °C−1 and led to an earlier start of intra-annual shoot growth. Despite this phenological shift, total time span of annual growth and shoot biomass were not affected. Drought changed the frequency and intensity of intra-annual shoot growth and advanced bud burst in the subsequent spring of a severe summer drought by 1–2 days. After re-wetting, shoot growth recovered within a few days, demonstrating the superior drought tolerance of this tree genus. Our findings show that phenological patterns of oaks are modified by warming and drought but also suggest that ontogenetic factors and/or limitations of water and nutrients counteract warming effects on the biomass and the entire span of annual shoot growth. PMID:24586988

  14. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. PMID:27152990

  15. Is Air Temperature Enough to Predict Lake Surface Temperature?

    NASA Astrophysics Data System (ADS)

    Piccolroaz, S.; Toffolon, M.; Majone, B.

    2014-12-01

    Lake surface water (LST) is a key factor that controls most of the physical and ecological processes occurring in lakes. Reliable estimates are especially important in the light of recent studies, which revealed that inland water bodies are highly sensitive to climate, and are rapidly warming throughout the world. However, an accurate estimation of LST usually requires a significant amount of information that is not always available. In this work, we present an application of air2water, a lumped model that simulates LST as a function of air temperature only. In addition, air2water allows for a qualitative evaluation of the depth of the epilimnion during the annual stratification cycle. The model consists in a simplification of the complete heat budget of the well-mixed surface layer, and has a few parameters (from 4 to 8 depending on the version) that summarize the role of the different heat flux components. Model calibration requires only air and water temperature data, possibly covering sufficiently long historical periods in order to capture inter-annual variability and long-term trends. During the calibration procedure, the information included in input data is retrieved to directly inform model parameters, which can be used to classify the thermal behavior of the lake. In order to investigate how thermal dynamics are related to morphological features, the model has been applied to 14 temperate lakes characterized by different morphological and hydrological conditions, by different sources of temperature data (buoys, satellite), and by variable frequency of acquisition. A good agreement between observed and simulated LST has been achieved, with a RMSE in the order of 1°C, which is fully comparable to the performances of more complex process-based models. This application allowed for a deeper understanding of the thermal response of lakes as a function of their morphology, as well as for specific analyses as for example the investigation of the exceptional

  16. Independent Confirmation of Global Land Warming without the Use of Station Temperatures

    NASA Astrophysics Data System (ADS)

    Compo, Gilbert; Sardeshmukh, Prashant; Whitaker, Jeffrey; Brohan, Philip; Jones, Philip; McColl, Chesley

    2013-04-01

    Confidence in estimates of 20th century land warming is limited by known issues with near-surface air temperature observations from land stations. Station siting, site moves, instrument changes, changing observing practices, urban effects, land cover, land use variations, and statistical processing have all been hypothesized as affecting the trends presented by the Intergovernmental Panel on Climate Change and others. Confidence in the observed rise of global land temperatures since the 1950s is important in assessments of anthropogenic effects on climate, so any artifacts in the observed decadal and centennial variations associated with these issues could have important consequences for scientific understanding and climate policy. Here we test the station temperature observations using a completely different approach to investigate global 20th century land warming. Specifically, we ignore all land temperature observations and instead infer the temperatures from global observations of subdaily barometric pressure, monthly HadISST1.1 sea surface temperature and sea-ice concentration, and of CO2, solar and volcanic radiative forcing agents using a physically-based data assimilation system called the 20th Century Reanalysis. This independent dataset reproduces both annual variations and centennial trends found in the observational near-surface air temperature datasets, thus demonstrating the robustness of previous conclusions based on them regarding global warming.

  17. A comparison of warming interventions on the temperatures of inpatients undergoing colorectal surgery.

    PubMed

    Nicholson, Martha

    2013-03-01

    This study compared the effects of two different warming interventions in the preoperative setting on the preoperative, intraoperative, and postoperative temperatures of patients undergoing colorectal surgery in an inpatient setting. The study was performed to determine whether prewarming patients for at least 30 minutes would result in postoperative temperatures of 36° C (96.8° F) or higher within 15 minutes of their arrival in the postanesthesia care unit. The results indicated that prewarming devices did not result in reduced proportions of patients who subsequently experienced hypothermia. One reason may be that all the patients were warmed with a forced-air warming device before induction in the OR. Our study does not recommend a specific intervention for a prewarming strategy but indicates that prewarming may contribute to normothermia in the immediate postoperative period. PMID:23452696

  18. Common Warm Dust Temperatures Around Main Sequence Stars

    NASA Technical Reports Server (NTRS)

    Morales, Farisa; Rieke, George; Werner, Michael; Stapelfeldt, Karl; Bryden, Geoffrey; Su, Kate

    2011-01-01

    We compare the properties of warm dust emission from a sample of main-sequence A-type stars (B8-A7) to those of dust around solar-type stars (F5-KO) with similar Spitzer Space Telescope Infrared Spectrograph/MIPS data and similar ages. Both samples include stars with sources with infrared spectral energy distributions that show evidence of multiple components. Over the range of stellar types considered, we obtain nearly the same characteristic dust temperatures (∼ 190 K and ∼60 K for the inner and outer dust components, respectively)-slightly above the ice evaporation temperature for the inner belts. The warm inner dust temperature is readily explained if populations of small grains are being released by sublimation of ice from icy planetesimals. Evaporation of low-eccentricity icy bodies at ∼ 150 K can deposit particles into an inner/warm belt, where the small grains are heated to dust Temperatures of -190 K. Alternatively, enhanced collisional processing of an asteroid belt-like system of parent planetesimals just interior to the snow line may account for the observed uniformity in dust temperature. The similarity in temperature of the warmer dust across our B8-KO stellar sample strongly suggests that dust-producing planetesimals are not found at similar radial locations around all stars, but that dust production is favored at a characteristic temperature horizon.

  19. The Summertime Warming Trends in Surface Water Temperature of the Great Lakes

    NASA Astrophysics Data System (ADS)

    Sugiyama, N.; Kravtsov, S.; Roebber, P.

    2014-12-01

    Over the past 30 years, the Laurentian Great Lakes have exhibited summertime warming trends in surface water temperature which were greater than those in surface air temperature of the surrounding land, by as much as an order of magnitude over some of the regions. For the years 1995-2012, Lake Superior exhibited the most dramatic warming trend in July-mean temperature, of 0.27±0.15 deg. C yr-1, based on the NOAA's GLSEA satellite observations. Shallower lakes, such as Lake Erie, exhibited smaller warming trends. In addition, within each lake, the warming was also the greatest in the regions of larger water depth; for example, some regions of Lake Superior deeper than 200m exhibited surface-water July-mean warming trends which exceeded 0.3 deg. C yr-1. We used a three-column lake model based on the one developed by Hostetler and Barnstein (1990) coupled with a two-layer atmospheric energy balance model to explore the physics behind these warming trends. We found that, as suggested by Austin and Colman (2007), the ice-albedo feedback plays an important role in amplifying the overlake warming trends. Our particular emphasis was on the question of whether the ice-albedo feedback alone is enough to account for lacustrine amplification of surface warming observed over the Great Lakes region. We found that the answer to this question depends on a number of model parameters, including the diffusion and light attenuation coefficients, which greatly affect the model's skill in reproducing the observed ice coverage of the deep lakes.

  20. Preventing inadvertent hypothermia: comparing two protocols for preoperative forced-air warming.

    PubMed

    Cobbe, Kerry-Anne; Di Staso, Renatta; Duff, Jed; Walker, Kim; Draper, Nicole

    2012-02-01

    Preoperative forced-air warming is one way of preventing inadvertent perioperative hypothermia. There is scant evidence, however, on the best warming method or the acceptability of these methods to patients. This pilot study compared two warming protocols: one that commenced at maximum temperature and was titrated down as requested (A) and one that commenced at near body temperature and was titrated up as tolerated (B). A crossover design was used in which each participant (n=10) received both protocols sequentially. The mean device temperature and length of time spent at maximum settings were greater for protocol A (43°C±0°C vs 41°C±1°C, P=.003; and 60±0 vs 41.5±2.8 minutes, P=.004). There was no difference in thermal comfort scores, participant temperature, or sweating between the two protocols. When asked, participants preferred protocol A to B (70% to 30%). Starting at higher device settings appears the more favorable of the two approaches. PMID:22264617

  1. Effect of warming temperatures on US wheat yields.

    PubMed

    Tack, Jesse; Barkley, Andrew; Nalley, Lawton Lanier

    2015-06-01

    Climate change is expected to increase future temperatures, potentially resulting in reduced crop production in many key production regions. Research quantifying the complex relationship between weather variables and wheat yields is rapidly growing, and recent advances have used a variety of model specifications that differ in how temperature data are included in the statistical yield equation. A unique data set that combines Kansas wheat variety field trial outcomes for 1985-2013 with location-specific weather data is used to analyze the effect of weather on wheat yield using regression analysis. Our results indicate that the effect of temperature exposure varies across the September-May growing season. The largest drivers of yield loss are freezing temperatures in the Fall and extreme heat events in the Spring. We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures. Our analysis indicates that there exists a tradeoff between average (mean) yield and ability to resist extreme heat across varieties. More-recently released varieties are less able to resist heat than older lines. Our results also indicate that warming effects would be partially offset by increased rainfall in the Spring. Finally, we find that the method used to construct measures of temperature exposure matters for both the predictive performance of the regression model and the forecasted warming impacts on yields. PMID:25964323

  2. Effect of warming temperatures on US wheat yields

    PubMed Central

    Tack, Jesse; Barkley, Andrew; Nalley, Lawton Lanier

    2015-01-01

    Climate change is expected to increase future temperatures, potentially resulting in reduced crop production in many key production regions. Research quantifying the complex relationship between weather variables and wheat yields is rapidly growing, and recent advances have used a variety of model specifications that differ in how temperature data are included in the statistical yield equation. A unique data set that combines Kansas wheat variety field trial outcomes for 1985–2013 with location-specific weather data is used to analyze the effect of weather on wheat yield using regression analysis. Our results indicate that the effect of temperature exposure varies across the September−May growing season. The largest drivers of yield loss are freezing temperatures in the Fall and extreme heat events in the Spring. We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures. Our analysis indicates that there exists a tradeoff between average (mean) yield and ability to resist extreme heat across varieties. More-recently released varieties are less able to resist heat than older lines. Our results also indicate that warming effects would be partially offset by increased rainfall in the Spring. Finally, we find that the method used to construct measures of temperature exposure matters for both the predictive performance of the regression model and the forecasted warming impacts on yields. PMID:25964323

  3. The Role of Anthropogenic-Induced Surface Temperature Change on Regional Enhanced Warming over East Asia

    NASA Astrophysics Data System (ADS)

    Guan, X.; Huang, J.; Guo, R.

    2014-12-01

    In this study, the long-term trend and decadal variability of surface air temperature (SAT) are studied by using observation data from 1901-2009. We found that the warming trends of the semi-arid regions are higher than other lands, which have increased 2.42°C as compared to the global annual mean temperature increase of 1.13°C over land. To investigate the causes of Enhanced Semi-Arid Warming (ESAW), we used an advanced dynamic-adjusted method proposed by Wallace et al. (2012) to analyse the contribution of dynamically-induced and anthropogenic-induced SAT changes to ESAW. In the process of dynamic adjustment, the temperature has been divided into two parts, one for the dynamic forcing induced temperature, and the other for the temperature associated with the build-up of greenhouse gases and the other various radiative forcing. The results show that the anthropogenic-warming peak over semi-arid region plays the main role in the ESAW. Such anthropogenic warming peak may be related to reduction of snow cover due to black carbon (BC) emission by fuels for winter residential heating. Besides the impact of BC in snow, the agricultural mulch creation, wind farms and other types of human activities may also make attribution to local SAT changes that need to be further studied.

  4. 10 CFR 431.72 - Definitions concerning commercial warm air furnaces.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....72 Section 431.72 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR... do not have any differing physical or functional characteristics that affect energy efficiency. Test... efficiency, water consumption, or water efficiency. Commercial warm air furnace means a warm air furnace...

  5. 10 CFR 431.72 - Definitions concerning commercial warm air furnaces.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning commercial warm air furnaces. 431.72 Section 431.72 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces § 431.72 Definitions...

  6. 10 CFR 431.72 - Definitions concerning commercial warm air furnaces.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Definitions concerning commercial warm air furnaces. 431.72 Section 431.72 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces § 431.72 Definitions...

  7. Air-fuel ratio control system for internal combustion engines capable of controlling air-fuel ratio in accordance with degree of warming-up of the engines

    SciTech Connect

    Hibino, Y.; Fukuzawa, T.

    1988-06-28

    This patent describes an air-fuel ratio control system for an internal combustion engine, the system having an automatic choke valve arranged in an intake passage of the engine, and exhaust gas sensor arranged in an exhaust passage of the engine and having an output characteristic linear with respect to the concentration of a specific component in exhaust gases from the engine, an air passage bypassing a throttle valve in the intake passage, an air-fuel ratio control valve arranged in the air passage, and disposed to be driven in response to an output from the exhaust gas sensor for controlling the air-fuel ratio of a mixture supplied to the engine, and temperature sensing means for sensing the degree of warming-up of the engine, the combination comprising; determining means for determining whether the exhaust gas has been activated; means for controlling the opening of the automatic choke valve in response to the degree of warming-up of the engine sensed by the temperature sensing means while the determining means determines that the exhaust gas sensor is inactive; means for determining the difference between a desired value of the air-fuel ratio and an actual value thereof sensed by the exhaust gas sensor, and for driving the automatic choke valve when the determined difference is larger than a predetermined value, and the air-fuel ratio control valve when the determined difference is smaller than the predetermined value, respectively, from the time the determining means determines for the first time that the exhaust gas sensor has become activated to the time the temperature sensing means detects completion of warming up of the engine; and means for driving the air-fuel ratio control valve in response to operating conditions of the engine so as to achieve a desired value of the air-fuel ratio, after the temperature sensing means detects completion of warming-up of the engine.

  8. Rice yields decline with higher night temperature from global warming.

    PubMed

    Peng, Shaobing; Huang, Jianliang; Sheehy, John E; Laza, Rebecca C; Visperas, Romeo M; Zhong, Xuhua; Centeno, Grace S; Khush, Gurdev S; Cassman, Kenneth G

    2004-07-01

    The impact of projected global warming on crop yields has been evaluated by indirect methods using simulation models. Direct studies on the effects of observed climate change on crop growth and yield could provide more accurate information for assessing the impact of climate change on crop production. We analyzed weather data at the International Rice Research Institute Farm from 1979 to 2003 to examine temperature trends and the relationship between rice yield and temperature by using data from irrigated field experiments conducted at the International Rice Research Institute Farm from 1992 to 2003. Here we report that annual mean maximum and minimum temperatures have increased by 0.35 degrees C and 1.13 degrees C, respectively, for the period 1979-2003 and a close linkage between rice grain yield and mean minimum temperature during the dry cropping season (January to April). Grain yield declined by 10% for each 1 degrees C increase in growing-season minimum temperature in the dry season, whereas the effect of maximum temperature on crop yield was insignificant. This report provides a direct evidence of decreased rice yields from increased nighttime temperature associated with global warming. PMID:15226500

  9. Airborne Asbestos Exposures from Warm Air Heating Systems in Schools.

    PubMed

    Burdett, Garry J; Dewberry, Kirsty; Staff, James

    2016-01-01

    The aim of this study was to investigate the concentrations of airborne asbestos that can be released into classrooms of schools that have amosite-containing asbestos insulation board (AIB) in the ceiling plenum or other spaces, particularly where there is forced recirculation of air as part of a warm air heating system. Air samples were collected in three or more classrooms at each of three schools, two of which were of CLASP (Consortium of Local Authorities Special Programme) system-built design, during periods when the schools were unoccupied. Two conditions were sampled: (i) the start-up and running of the heating systems with no disturbance (the background) and (ii) running of the heating systems during simulated disturbance. The simulated disturbance was designed to exceed the level of disturbance to the AIB that would routinely take place in an occupied classroom. A total of 60 or more direct impacts that vibrated and/or flexed the encapsulated or enclosed AIB materials were applied over the sampling period. The impacts were carried out at the start of the sampling and repeated at hourly intervals but did not break or damage the AIB. The target air volume for background samples was ~3000 l of air using a static sampler sited either below or ~1 m from the heater outlet. This would allow an analytical sensitivity (AS) of 0.0001 fibres per millilitre (f ml(-1)) to be achieved, which is 1000 times lower than the EU and UK workplace control limit of 0.1 f ml(-1). Samples with lower volumes of air were also collected in case of overloading and for the shorter disturbance sampling times used at one site. The sampler filters were analysed by phase contrast microscopy (PCM) to give a rapid determination of the overall concentration of visible fibres (all types) released and/or by analytical transmission electron microscopy (TEM) to determine the concentration of asbestos fibres. Due to the low number of fibres, results were reported in terms of both the calculated

  10. Airborne Asbestos Exposures from Warm Air Heating Systems in Schools

    PubMed Central

    Burdett, Garry J.; Dewberry, Kirsty; Staff, James

    2016-01-01

    The aim of this study was to investigate the concentrations of airborne asbestos that can be released into classrooms of schools that have amosite-containing asbestos insulation board (AIB) in the ceiling plenum or other spaces, particularly where there is forced recirculation of air as part of a warm air heating system. Air samples were collected in three or more classrooms at each of three schools, two of which were of CLASP (Consortium of Local Authorities Special Programme) system-built design, during periods when the schools were unoccupied. Two conditions were sampled: (i) the start-up and running of the heating systems with no disturbance (the background) and (ii) running of the heating systems during simulated disturbance. The simulated disturbance was designed to exceed the level of disturbance to the AIB that would routinely take place in an occupied classroom. A total of 60 or more direct impacts that vibrated and/or flexed the encapsulated or enclosed AIB materials were applied over the sampling period. The impacts were carried out at the start of the sampling and repeated at hourly intervals but did not break or damage the AIB. The target air volume for background samples was ~3000 l of air using a static sampler sited either below or ~1 m from the heater outlet. This would allow an analytical sensitivity (AS) of 0.0001 fibres per millilitre (f ml−1) to be achieved, which is 1000 times lower than the EU and UK workplace control limit of 0.1 f ml−1. Samples with lower volumes of air were also collected in case of overloading and for the shorter disturbance sampling times used at one site. The sampler filters were analysed by phase contrast microscopy (PCM) to give a rapid determination of the overall concentration of visible fibres (all types) released and/or by analytical transmission electron microscopy (TEM) to determine the concentration of asbestos fibres. Due to the low number of fibres, results were reported in terms of both the calculated

  11. Upper Temperature Limits of Tropical Marine Ectotherms: Global Warming Implications

    PubMed Central

    Nguyen, Khanh Dung T.; Morley, Simon A.; Lai, Chien-Houng; Clark, Melody S.; Tan, Koh Siang; Bates, Amanda E.; Peck, Lloyd S.

    2011-01-01

    Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour−1, the upper lethal temperature range of intertidal ectotherms was 41–52°C, but this range was narrower and reduced to 37–41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2–3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming. PMID:22242115

  12. Tropical Intraseasonal Air-Sea Exchanges during the 1997 Pacific Warming

    NASA Technical Reports Server (NTRS)

    Sui, C.-H.; Lau, K.-M.; Chou, S.-H.; Wang, Zihou

    1999-01-01

    The Madden Julian Oscillations (MJO) and associated westerly wind (WW) events account for much of the tropical intraseasonal variability (TISV). The TISV has been suggested as an important stochastic forcing that may be one of the underlying causes for the observed irregularities of the El Nino-Southern Oscillation (ENSO). Recent observational studies and theories of interannual to interdecadal-scale variability suggest that ENSO may arise from different mechanisms depending on the basic states. The Pacific warming event of 1997, being associated with a period of strong MJO and WW events, serves as a natural experiment for studying the possible role of TISV in triggering an ENSO event. We have performed a combined statistical and composite analysis of surface WW events based on the assimilated surface wind and sea level pressure for the period of 1980-1993, the SSM/I wind for the period of 1988-1997, and OLR. Results indicates that extratropical forcing contribute significantly to the evolution of MJO and establishment of WW events over the Pacific warm pool. Following the major WW events, there appeared an eastward extension of equatorial warm SST anomalies from the western Pacific warm pool. Such tropical-extratropical interaction is particularly clear in the winter of 96-97 that leads to the recent warming event in 1997/98. From the above discussion, our current study on this subject is based on the hypothesis that 1) there is an enhanced air-sea interaction associated with TISV and the northerly surges from the extratropics in the initial phase of the 97/98 warming event, and 2) the relevant mechanisms are functions of the basic state of the coupled system (in terms of SST distribution and atmospheric mean circulation) that varies at the interannual and interdecadal time scale. We are analyzing the space-time structure of the northerly surges, their association with air-sea fluxes and upper ocean responses during the period of September 1996 to June 1997. The

  13. Role of radiatively forced temperature changes in enhanced semi-arid warming in the cold season over east Asia

    NASA Astrophysics Data System (ADS)

    Guan, X.; Huang, J.; Guo, R.; Yu, H.; Lin, P.; Zhang, Y.

    2015-12-01

    As climate change has occurred over east Asia since the 1950s, intense interest and debate have arisen concerning the contribution of human activities to the observed warming in past decades. In this study, we investigate regional surface temperature change during the boreal cold season using a recently developed methodology that can successfully identify and separate the dynamically induced temperature (DIT) and radiatively forced temperature (RFT) changes in raw surface air temperature (SAT) data. For regional averages, DIT and RFT contribute 44 and 56 % to the SAT over east Asia, respectively. The DIT changes dominate the SAT decadal variability and are mainly determined by internal climate variability, represented by the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO). Radiatively forced SAT changes have made a major contribution to the global-scale warming trend and the regional-scale enhanced semi-arid warming (ESAW). Such enhanced warming is also found in radiatively forced daily maximum and minimum SAT. The long-term global-mean SAT warming trend is mainly related to radiative forcing produced by global well-mixed greenhouse gases. The regional anthropogenic radiative forcing, however, caused the enhanced warming in the semi-arid region, which may be closely associated with local human activities. Finally, the relationship between the so-called "global warming hiatus" and regional enhanced warming is discussed.

  14. High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

  15. The warming trend of ground surface temperature in the Choshui Alluvial Fan, western central Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, W.; Chang, M.; Chen, J.; Lu, W.; Huang, C. C.; Wang, Y.

    2013-12-01

    Heat storage in subsurface of the continents forms a fundamental component of the global energy budget and plays an important role in the climate system. Several researches revealed that subsurface temperatures were being increased to 1.8-2.8°C higher in mean ground surface temperature (GST) for some Asian cities where are experiencing a rapid growth of population. Taiwan is a subtropic-tropic island with densely populated in the coastal plains surrounding its mountains. We investigate the subsurface temperature distribution and the borehole temperature-depth profiles by using groundwater monitoring wells in years 2000 and 2010. Our data show that the western central Taiwan plain also has been experiencing a warming trend but with a higher temperatures approximately 3-4 °C of GST during the last 250 yrs. We suggest that the warming were mostly due to the land change to urbanization and agriculture. The current GSTs from our wells are approximately 25.51-26.79 °C which are higher than the current surface air temperature (SAT) of 23.65 °C. Data from Taiwan's weather stations also show 1-1.5 °C higher for the GST than the SAT at neighboring stations. The earth surface heat balance data indicate that GST higher than SAT is reasonable. More researches are needed to evaluate the interaction of GST and SAT, and how a warming GST's impact to the SAT and the climate system of the Earth.

  16. Contrasting development of Pleistocene warm temperature regimes across the Arctic

    NASA Astrophysics Data System (ADS)

    Bauch, Henning; Nalan Koç, Nalan

    2014-05-01

    Late Pleistocene records from the North Atlantic characterize intervals of major interglacials as times of comparable ocean warmth (± 1-2°C) due to enhanced poleward flow of warm North Atlantic surface waters. A number of recent observations and interpretations from various climate archives would imply varying impacts on the arctic environment during older interglacials. Among warm periods of the past 500 ka, marine isotope stage 11 (MIS 11) is often named as the prominent interglacial phase with a particularly tight global-scale climate connection. For Greenland, it was even suggested that the ice sheet was so strongly reduced in size that trees were able to thrive. And as noted in records from Lake El'gygytgyn in NE Siberia, average temperatures and precipitations exceeded those of the Holocene by far. Indeed, this interpretation of a rather moist and warm climate over Siberia seems to be in line also with assumptions concluded from other lake (Baikal) and speleothem records. In terms of meridional transfer of ocean-atmosphere heat across the North Atlantic, the Nordic Seas comprise the major gateway to the Arctic Ocean. By investigating in detail the oceanic surface ocean warmth during MIS 11 we cannot identify overly enhanced heat flow from the North Atlantic into the Arctic during this interglacial interval. As further deduced from our data, subsequent warm periods (e.g., MIS 5e and MIS 1) appear to have had significantly warmer surface ocean conditions than MIS 11. Moreover, sediment records from close to Greenland would imply a very active eastern ice sheet margin throughout MIS11 with regard to iceberg release rates and occurrence of sea ice. It is therefore proposed that the observation of rather cold surface conditions in the Nordic Seas but comparatively warm temperature regime over the Pacific side of the Arctic either resulted in or caused a distinct cross-arctic climate contrast. That situation significantly changed atmospheric circulation patterns

  17. Persistent Cold Air Outbreaks over North America Under Climate Warming

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Leung, L. R.; Lu, J.

    2014-12-01

    This study evaluates the change of cold air outbreaks (CAO) over North America using Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble of global climate simulations as well as regional high resolution climate simulations. In future, while robust decrease of CAO duration dominates in most of the North America, the decrease over northwestern U.S. was found to have much smaller magnitude than the surrounding regions. We found statistically significant increase of the sea level pressure over gulf of Alaska, leading to the advection of cold air to northwestern U.S.. By shifting the probability distribution of present temperature towards future warmer conditions, we identified the changes in large scale circulation contribute to about 50% of the enhanced sea level pressure. Using the high resolution regional climate model results, we found that increases of existing snowpack could potentially trigger the increase of CAO in the near future over the southwestern U.S. and Rocky Mountain through surface albedo effects. By the end of this century, the top 5 most extreme historical CAO events may still occur and wind chill warning will continue to have societal impacts over North America in particular over northwestern United States.

  18. Surface Temperature variability from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Dang, V. T.; Aumann, H. H.

    2015-12-01

    To address the existence and possible causes of the climate hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014for the day and night conditions. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We compare the satellite data with the new surface data produced by Karl et al. (2015) who denies the reality of the climate hiatus. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The day-night difference is an indicator of the anthropogenic trend. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  19. Variability of Winter Air Temperature in Mid-Latitude Europe

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

    2002-01-01

    The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

  20. On the Regulation of the Pacific Warm Pool Temperature

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Chou, Sue-Hsien; Chan, Pui-King; Lau, William K. M. (Technical Monitor)

    2002-01-01

    In the tropical western Pacific, regions of the highest sea surface temperature (SST) and the largest cloud cover are found to have the largest surface heating, primarily due to the weak evaporative cooling associated with weak winds. This situation is in variance with the suggestions that the temperature in the Pacific warm pool is regulated either by the reduced solar heating due to an enhanced cloudiness or by the enhanced evaporative cooling due to an elevated SST. It is clear that an enhanced surface heating in an enhanced convection region is not sustainable and must be interrupted by variations in large-scale atmospheric circulation. As the deep convective regions shift away from regions of high SST due primarily to seasonal variation and secondarily to interannual variation of the large-scale atmospheric and oceanic circulation, both trade wind and evaporative cooling in the high SST region increase, leading to a reduction in SST. We conclude that the evaporative cooling associated with the seasonal and interannual variations of trade winds in the primary factor that prevent the warm pool SST from increasing to a value much higher than what is observed.

  1. Effect of dry warm air on respiratory water loss in children with exercise-induced asthma.

    PubMed

    Tabka, Z; Ben Jebria, A; Vergeret, J; Guenard, H

    1988-07-01

    The variation in respiratory water loss (RWL) over time, expressed as the mass of water vapor lost per liter (body temperature and pressure, saturated) of ventilation (MH2O), was investigated in two groups: (1) children with exercise-induced asthma; and (2) healthy children. Children were matched for age and sex and went without medication for at least 12 hours before each experiment. The children breathed dry warm air (TI = 28.4 degrees C +/- 0.3 degree C) for 15 minutes while bicycling at constant and moderate work load (50 W). The MH2O was measured by collecting and weighing the expired water vapor (1) at rest breathing in warm conditions of inspired gas (control values), (2) every five minutes during exercise while breathing dry warm air, and (3) four minutes after the end of exercise. Pulmonary function tests were performed before and six minutes after exercise. The results were abnormal only in children with exercise-induced asthma. During exercise, RWL significantly fell (compared to control value) at the tenth and 15th minute in both groups. Whereas normal subjects recovered their initial values for MH2O four minutes after stopping exercise, asthmatic children still had a reduction in respiratory water loss. During exercise, MH2O decreased a little more in healthy than in asthmatic children. The decrease in MH2O in both groups suggests that the means to fully humidify expired gas are overwhelmed by thermal stress. The lack of increase in MH2O in asthmatic children on stopping exercise suggests that the airway mucosa is unable to produce enough water vapor and is thus dehydrated and probably hyperosmotic. PMID:3383660

  2. Historical changes in air temperature are evident in temperature fluxes measured in the sub-soil.

    NASA Astrophysics Data System (ADS)

    Fraser, Fiona; McCormick, Benjamin; Hallett, Paul; Wookey, Philip; Hopkins, David

    2013-04-01

    Warming trends in soil temperature have implications for a plethora of soil processes, including exacerbated climate change through the net release of greenhouse gases. Whereas long-term datasets of air temperature changes are abundant, a search of scientific literature reveals a lack of information on soil temperature changes and their specific consequences. We analysed five long-term data series collected in the UK (Dundee and Armagh) and Canada (Charlottetown, Ottawa and Swift Current). They show that the temperatures of soils at 5 - 20 cm depth, and sub-soils at 30 - 150 cm depth, increased in line with air temperature changes over the period 1958 - 2003. Differences were found, however, between soil and air temperatures when data were sub-divided into seasons. In spring, soil temperature warming ranged from 0.19°C at 30 cm in Armagh to 4.30°C at 50 cm in Charlottetown. In summer, however, the difference was smaller and ranged from 0.21°C at 10 cm in Ottawa to 3.70°C at 50 cm in Charlottetown. Winter temperatures were warmer in soil and ranged from 0.45°C at 5 cm in Charlottetown to 3.76°C at 150 cm in Charlottetown. There were significant trends in changes to soil temperature over time, whereas air temperature trends tended only to be significant in winter (changes range from 1.27°C in Armagh to 3.35°C in Swift Current). Differences in the seasonal warming patterns between air and soil temperatures have potential implications for the parameterization of models of biogeochemical cycling.

  3. Persistent cold air outbreaks over North America in a warming climate

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Leung, L. Ruby; Lu, Jian; Masato, Giacomo

    2015-04-01

    This study examines future changes of cold air outbreaks (CAOs) using a multi-model ensemble of global climate simulations from the Coupled Model Intercomparison Project Phase 5 and high resolution regional climate simulations. Overall, climate models agree on a dip in CAO duration across North America, but the percentage change is consistently smaller from western Canada to the upper mid-western US with historically more frequent CAO. By decomposing the changes of the probability density function of daily surface temperature into changes due to mean warming and changes in standard deviation (std) and skewness/higher order moments, the contributions of each factor to CAO changes are quantified. Results show that CAO changes can be explained largely by the mean warming, but the decrease in temperature std contributes to about 20% reduction of CAO from Alaska to northeastern US and eastern Canada possibly due to the Arctic amplification and weakening of storm track. A thermodynamical modulation of the skewness called the ‘0 °C mode’ effect is found to operate prominently along the 0 °C isotherm hemispherically and reduce CAO in western and northeastern US with winter snow cover by up to 10%. This effect also produces a manifold increase in CAO events over the Arctic sea ice. An increased frequency in atmospheric blocking also contributes to increases in CAO duration over Alaska and the Arctic region. Regional simulations revealed more contributions of existing snowpack to CAO in the near future over the Rocky Mountain, southwestern US, and Great Lakes areas through surface albedo effects. Overall, the multi-model projections emphasize that cold extremes do not completely disappear in a warming climate. Concomitant with the relatively smaller reduction in CAO events in northwestern US, the top five most extreme CAO events may still occur, and wind chill will continue to have societal impacts in that region.

  4. General dissipation coefficient in low-temperature warm inflation

    SciTech Connect

    Bastero-Gil, Mar; Berera, Arjun; Rosa, João G.; Ramos, Rudnei O. E-mail: ab@ph.ed.ac.uk E-mail: joao.rosa@ed.ac.uk

    2013-01-01

    In generic particle physics models, the inflaton field is coupled to other bosonic and fermionic fields that acquire large masses during inflation and may decay into light degrees of freedom. This leads to dissipative effects that modify the inflationary dynamics and may generate a nearly-thermal radiation bath, such that inflation occurs in a warm rather than supercooled environment. In this work, we perform a numerical computation and obtain expressions for the associated dissipation coefficient in supersymmetric models, focusing on the regime where the radiation temperature is below the heavy mass threshold. The dissipation coefficient receives contributions from the decay of both on-shell and off-shell degrees of freedom, which are dominant for small and large couplings, respectively, taking into account the light field multiplicities. In particular, we find that the contribution from on-shell decays, although Boltzmann-suppressed, can be much larger than that of virtual modes, which is bounded by the validity of a perturbative analysis. This result opens up new possibilities for realizations of warm inflation in supersymmetric field theories.

  5. Constant diurnal temperature regime alters the impact of simulated climate warming on a tropical pseudoscorpion

    PubMed Central

    Zeh, Jeanne A.; Bonilla, Melvin M.; Su, Eleanor J.; Padua, Michael V.; Anderson, Rachel V.; Zeh, David W.

    2014-01-01

    Recent theory suggests that global warming may be catastrophic for tropical ectotherms. Although most studies addressing temperature effects in ectotherms utilize constant temperatures, Jensen's inequality and thermal stress considerations predict that this approach will underestimate warming effects on species experiencing daily temperature fluctuations in nature. Here, we tested this prediction in a neotropical pseudoscorpion. Nymphs were reared in control and high-temperature treatments under a constant daily temperature regime, and results compared to a companion fluctuating-temperature study. At constant temperature, pseudoscorpions outperformed their fluctuating-temperature counterparts. Individuals were larger, developed faster, and males produced more sperm, and females more embryos. The greatest impact of temperature regime involved short-term, adult exposure, with constant temperature mitigating high-temperature effects on reproductive traits. Our findings demonstrate the importance of realistic temperature regimes in climate warming studies, and suggest that exploitation of microhabitats that dampen temperature oscillations may be critical in avoiding extinction as tropical climates warm. PMID:24424082

  6. Sensitivity of New England Stream Temperatures to Air Temperature and Precipitation Under Projected Climate

    NASA Astrophysics Data System (ADS)

    Huang, T.; Samal, N. R.; Wollheim, W. M.; Stewart, R. J.; Zuidema, S.; Prousevitch, A.; Glidden, S.

    2015-12-01

    The thermal response of streams and rivers to changing climate will influence aquatic habitat. This study examines the impact that changing climate has on stream temperatures in the Merrimack River, NH/MA USA using the Framework for Aquatic Modeling in the Earth System (FrAMES), a spatially distributed river network model driven by air temperature, air humidity, wind speed, precipitation, and solar radiation. Streamflow and water temperatures are simulated at a 45-second (latitude x longitude) river grid resolution for 135 years under historical and projected climate variability. Contemporary streamflow (Nash-Sutcliffe Coefficient = 0.77) and river temperatures (Nash-Sutcliffe Coefficient = 0.89) matched at downstream USGS gauge data well. A suite of model runs were made in combination with uniformly increased daily summer air temperatures by 2oC, 4 oC and 6 oC as well as adjusted precipitation by -40%, -30%, -20%, -10% and +10% as a sensitivity analysis to explore a broad range of potential future climates. We analyzed the summer stream temperatures and the percent of river length unsuitable for cold to warm water fish habitats. Impacts are greatest in large rivers due to the accumulation of river temperature warming throughout the entire river network. Cold water fish (i.e. brook trout) are most strongly affected while, warm water fish (i.e. largemouth bass) aren't expected to be impacted. The changes in stream temperatures under various potential climate scenarios will provide a better understanding of the specific impact that air temperature and precipitation have on aquatic thermal regimes and habitat.

  7. Relationship between the large-scale air circulation and frequency of very warm days in Romania

    NASA Astrophysics Data System (ADS)

    Stefan, Sabina; Barbu, Nicu; Baciu, Madalina

    2015-04-01

    In this work is investigated the relationship between the large-scale air circulation and frequency of very warm days (frequency of days with maximum temperature greater or equal to 90th percentile - FrTmax90). This analysis is conducted for summer and winter over the period 1962-2010. Daily temperature data recorded at 85 Romanian meteorological stations with complete observations over the study period were used to calculate the FrTmax90 for summer and winter. Daily air circulation types computed by using two objective catalogues, namely GWT (GrossWetter-Typen) and WLK (WetterLargenKlassifikation) from COST733Action were used to calculate the air circulation frequency for summer and winter. NCEP/NCAR gridded reanalysis data sets were used. For the GWT catalogue the sea level pressure data sets were used to classify the air circulation in the 18 types. In the case of the WLK catalogue the geopotential height at 925 and 500 hPa, zonal and meridional components of wind vector at 700 hPa and precipitable water content for the entire atmospheric column were used to classify the air circulation in the 40 types. For winter were obtained 4 clusters and for summer 8 clusters of FrTmax90 by using a clusterization method. These clusters present homogeneity related to the FrTmax90. The Pearson correlation coefficient (R) is calculated between the FrTmax90 and the air circulation types. The results show that correlation coefficients are greatest in winter than in summer for the GWT catalogue compared to the WLK catalogue. The greatest correlation coefficients was obtained during winter for southwestern-anticyclones (SW[A]) circulation type for all the 4 clusters according to the GWT catalogue. The northwestern-anticyclones-wet (NW-AAW) circulation type presents the greatest correlation coefficient only for the cluster 3 according to the WLK catalogue. We can note that these results depend on the both large-scale air circulation and orography (the Carpathians).

  8. Root-Zone Warming Differently Benefits Mature and Newly Unfolded Leaves of Cucumis sativus L. Seedlings under Sub-Optimal Temperature Stress

    PubMed Central

    Miao, Yanxiu; Gao, Lihong

    2016-01-01

    Sub-optimal temperature extensively suppresses crop growth during cool-season greenhouse production. Root-zone (RZ) warming is considered an economical option to alleviate crop growth reduction. In this study we cultivated cucumber seedlings in nutrient solution under different air-RZ temperature treatments to investigate the effects of RZ warming on seedling growth- and photosynthesis-related parameters in leaves. The air-RZ temperature treatments included sub-optimal RZ temperature 13°C and sub-optimal air temperature 20/12°C (day/night) (S13), RZ warming at 19°C and sub-optimal air temperature (S19), and RZ warming at 19°C and optimal air temperature 26/18°C (day/night) (O19). In addition, for each air-RZ temperature treatment, half of the seedlings were also treated with 2% (m/m) polyethylene glycol (PEG) dissolved in nutrient solution to distinguish the effect of root-sourced water supply from RZ temperature. At the whole-plant level, S19 significantly increased the relative growth rate (RGR) by approximately 18% compared with S13, although the increase was less than in O19 (50%) due to delayed leaf emergence. S19 alleviated both diffusive and metabolic limitation of photosynthesis in mature leaves compared with S13, resulting in a photosynthetic rate similar to that in O19 leaves. In newly unfolded leaves, S19 significantly promoted leaf area expansion and alleviated stomatal limitation of photosynthesis compared with S13. PEG addition had a limited influence on RGR and leaf photosynthesis, but significantly suppressed new leaf expansion. Thus, our results indicate that under sub-optimal temperature conditions, RZ warming promotes cucumber seedling growth by differently benefiting mature and newly unfolded leaves. In addition, RZ warming enhanced root-sourced water supply, mainly promoting new leaf expansion, rather than photosynthesis. PMID:27152599

  9. Root-Zone Warming Differently Benefits Mature and Newly Unfolded Leaves of Cucumis sativus L. Seedlings under Sub-Optimal Temperature Stress.

    PubMed

    Wang, Xiaozhuo; Zhang, Weihua; Miao, Yanxiu; Gao, Lihong

    2016-01-01

    Sub-optimal temperature extensively suppresses crop growth during cool-season greenhouse production. Root-zone (RZ) warming is considered an economical option to alleviate crop growth reduction. In this study we cultivated cucumber seedlings in nutrient solution under different air-RZ temperature treatments to investigate the effects of RZ warming on seedling growth- and photosynthesis-related parameters in leaves. The air-RZ temperature treatments included sub-optimal RZ temperature 13°C and sub-optimal air temperature 20/12°C (day/night) (S13), RZ warming at 19°C and sub-optimal air temperature (S19), and RZ warming at 19°C and optimal air temperature 26/18°C (day/night) (O19). In addition, for each air-RZ temperature treatment, half of the seedlings were also treated with 2% (m/m) polyethylene glycol (PEG) dissolved in nutrient solution to distinguish the effect of root-sourced water supply from RZ temperature. At the whole-plant level, S19 significantly increased the relative growth rate (RGR) by approximately 18% compared with S13, although the increase was less than in O19 (50%) due to delayed leaf emergence. S19 alleviated both diffusive and metabolic limitation of photosynthesis in mature leaves compared with S13, resulting in a photosynthetic rate similar to that in O19 leaves. In newly unfolded leaves, S19 significantly promoted leaf area expansion and alleviated stomatal limitation of photosynthesis compared with S13. PEG addition had a limited influence on RGR and leaf photosynthesis, but significantly suppressed new leaf expansion. Thus, our results indicate that under sub-optimal temperature conditions, RZ warming promotes cucumber seedling growth by differently benefiting mature and newly unfolded leaves. In addition, RZ warming enhanced root-sourced water supply, mainly promoting new leaf expansion, rather than photosynthesis. PMID:27152599

  10. Crowdsourcing urban air temperatures from smartphone battery temperatures

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James C. R.; Leijnse, Hidde; Steeneveld, Gert-Jan; Horn, Berthold K. P.; Uijlenhoet, Remko

    2014-05-01

    Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. It has been shown that a straightforward heat transfer model can be employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. The methodology has been applied to Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree

  11. Observations of Cooling Summer Daytime Temperatures (1948-2005) in Growing Urban Coastal California Air Basins

    NASA Astrophysics Data System (ADS)

    Bornstein, R.; Lebassi, B.; Gonzalez, J.

    2008-12-01

    The study evaluated long-term (1948-2005) air temperatures in California (CA) during summer (June- August). The aggregate CA results showed asymmetric warming, as daily minimum temperatures increased faster than daily maximum temperatures. The spatial distributions of daily maximum temperatures in the heavily urbanized South Coast and San Francisco Bay Area air basins, however, exhibited a complex pattern, with cooling at low-elevation (mainly urban) coastal-areas and warming at (mainly rural) inland areas. Previous studies have suggested that cooling summer max temperatures in CA were due to increased irrigation, coastal upwelling, or cloud cover. The current hypothesis, however, is that this temperature pattern arises from a 'reverse-reaction' to greenhouse gas (GHG) induced global-warming. In this hypothesis, the global warming of inland areas resulted in an increased (cooling) sea breeze activity in coastal areas. The coastal cooling thus resulted as urban heat island (UHI) warming was weaker than the reverse-reaction cooling; if there was no UHI effect, then the cooling would be even stronger. The cooling or warming trends at several pairs of nearby urban and non- urban sites were compared in an effort to separate out the urban heat island (UHI) and global warming components of the trend. Average temperatures from global circulation models show warming that decreases from inland areas of California to its coastal areas. Such large scale models, however, cannot resolve these smaller scale topographic and coastal effects. Meso-scale modeling on a 4 km grid is thus being carried out to evaluate the contributions from GHG global-warming and land-use changes, including UHI development, to the observed trends. Significant societal impacts may result from this observed reverse-reaction to GHG- warming; possible beneficial effects include decreased maximum: O3 levels, human thermal-stress, and per- capita energy requirements for cooling.

  12. Prevention of perioperative hypothermia with forced-air warming systems and upper-body blankets.

    PubMed

    Perl, Thorsten; Bräuer, Anselm; Quintel, Michael

    2006-01-01

    Forced-air warming is known as an effective procedure in prevention and treatment of perioperative hypothermia. Hypothermia is associated with disturbances of coagulation, raises postoperative oxygen consumption by shivering, increases cardiac morbidity, leads to a higher incidence of wound infection, and prolongs hospital stay. Additionally, preoperative local warming reduces the incidence of wound infection after clean surgery. In an animal experiment it has been demonstrated that even during large abdominal operations the major source of heat loss was the skin. Although evaporation accounted for the largest heat loss from the abdominal cavity, it was a minor source due to the smaller heat losing area. As a consequence, reduction of heat loss from the skin is the most promising approach to avoid hypothermia. During abdominal surgery and lower-limb surgery, the use of upper blankets is favourable. The use of upper-body blankets implies a reduction of heat loss in a relevant area and, furthermore, a heat gain. The covered area is approximately 0.35 m2, or approximately 15%-20% of body surface. The heat balance in this area can be changed by 46.1W to 55.0W by forced-air warming systems with upper body blankets. Depending on the surgical procedure and resulting fluid demand, forced-air warming with upper-body blankets-in combination with insulation and fluid warming-is an effective method to prevent perioperative hypothermia. PMID:17029156

  13. Spatio-temporal analysis of warming in Bangladesh using recent observed temperature data and GIS

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Rejaur; Lateh, Habibah

    2016-05-01

    This study focused on the annual and seasonal warming at local scale by analysing the trends, anomalies, change points and shifting of isotherm in temperature from 34 meteorological stations distributed over Bangladesh, spanning 40 years from the year 1971-2010. For trends, a linear regression using least square model was applied. Anomalies were calculated as a difference between the reference (1971-2000 mean) and actual occurrence value. Inverse distance weighted interpolation and GIS techniques were used to find out the spatial pattern of warming. Besides, the sequential version of the Mann-Kendall test was applied to detect the changing point of warming. Direction of shifting of warming was detected by the decadal distribution pattern of specific isotherms which were generated using GIS. The result reveals that the climate of Bangladesh undergone a significant warming during the period 1971-2010, 0.020 °C per year (for annual mean) and the maximum temperature warmed more than the minimum temperature (0.022 vs. 0.018 °C per year). On a seasonal basis, hot summer, humid summer and dry winter also show significant warming, 0.022, 0.026 and 0.011 °C per year, respectively. The warming of maximum temperature (0.032 °C per year) in humid summer was greater than other seasons, contributed more on annual warming. Spatial patterns indicate that geographically the warming varied significantly and some places warming exit 2.0 °C and reached up to 3.2 °C. The north western, north eastern, southern and south eastern parts of the country are more susceptible to rising temperature. In 2010, mean annual temperature was 0.84 °C warmer than the base period (1971-2000) mean. The significant warmest period was spread across the year 1995-2010, with 2010 being the warmest year. Statistically significant warming was began in early 1990's and the years 1990, 1994 and 1997 identified as important abrupt change points of warming. Moreover, a remarkably northward and north

  14. Multi-sliding time windows based changing trend of mean temperature and its association with the global-warming hiatus

    NASA Astrophysics Data System (ADS)

    Shi, Yan; Zhai, Panmao; Jiang, Zhihong

    2016-04-01

    Based on three global annual mean surface temperature time series and three Chinese annual mean surface air temperature time series, climate change trends on multiple timescales are analyzed by using the trend estimation method of multi-sliding time windows. The results are used to discuss the so-called global-warming hiatus during 1998-2012. It is demonstrated that different beginning and end times have an obvious effect on the results of the trend estimation, and the implications are particularly large when using a short window. The global-warming hiatus during 1998-2012 is the result of viewing temperature series on short timescales; and the events similar to it, or the events with even cold tendencies, have actually occurred many times in history. Therefore, the global-warming hiatus is likely to be a periodical feature of the long-term temperature change. It mainly reflects the decadal variability of temperature, and such a phenomenon in the short term does not alter the overall warming trend in the long term.

  15. Warm Ocean Temperatures Blanket the Far-Western Pacific

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These data, taken during a 10-day collection cycle ending March 9, 2001, show that above-normal sea-surface heights and warmer ocean temperatures(indicated by the red and white areas) still blanket the far-western tropical Pacific and much of the north (and south) mid-Pacific. Red areas are about 10centimeters (4 inches) above normal; white areas show the sea-surface height is between 14 and 32 centimeters (6 to 13 inches) above normal.

    This build-up of heat dominating the Western Pacific was first noted by TOPEX/Poseidon oceanographers more than two years ago and has outlasted the El Nino and La Nina events of the past few years. See: http://www.jpl.nasa.gov/elnino/990127.html . This warmth contrasts with the Bering Sea, Gulf of Alaska and tropical Pacific where lower-than-normal sea levels and cool ocean temperatures continue (indicated by blue areas). The blue areas are between 5 and 13centimeters (2 and 5 inches) below normal, whereas the purple areas range from 14 to 18 centimeters (6 to 7 inches) below normal. Actually, the near-equatorial ocean cooled through the fall of 2000 and into mid-winter and continues almost La Nina-like.

    Looking at the entire Pacific basin, the Pacific Decadal Oscillation's warm horseshoe and cool wedge pattern still dominates this sea-level height image. Most recent National Oceanic and Atmospheric Administration (NOAA) sea-surface temperature data also clearly illustrate the persistence of this basin-wide pattern. They are available at http://psbsgi1.nesdis.noaa.gov:8080/PSB/EPS/SST/climo.html

    The U.S.-French TOPEX/Poseidon mission is managed by JPL for NASA's Earth Science Enterprise, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. For more information on the TOPEX/Poseidon project, see: http://topex-www.jpl.nasa.gov

  16. The "blob of death", or how warm air advection causes rapid ice melt

    NASA Astrophysics Data System (ADS)

    Tjernström, Michael; Shupe, Matthew; Achtert, Peggy; Brooks, Barbara; Brooks, Ian; Johnston, Paul; Persson, Ola; Prytherch, John; Salisbury, Dominic; Sedlar, Joseph; Sotiropoulou, Georgia; Wolfe, Dan

    2015-04-01

    The Arctic Clouds in Summer Experiment (ACSE) program obtained measurements of surface energy fluxes, boundary-layer structure, cloud macro- and micro-physical structure, and upper-ocean thermal and salinity structure from pack-ice and open-water regions in the eastern Arctic from early July to early October 2014. ACSE was divided into two legs. The first took a route from Tromsö, Norway, to Barrow, Alaska, during late summer (early July to late August) mostly on the Siberian Shelf, while the second leg was from traversed back mostly north of the shelf during September and early October. This paper will present ACSE and show examples of some results. Energy fluxes at the surface determine the annual summer melt and autumn freeze-up of Arctic sea ice, but are strongly modulated by interactions between atmospheric, ocean, and sea-ice processes. ACSE summer measurements showed energy flux surpluses leading to significant surface melt, while late August and September measurements showed deficits, leading to freeze-up of sea ice and the ocean surface. A weeklong episode with intensive melt resulting from warm air advection from continental Russia will be presented and discussed. During this episode, temperatures up to 20 °C was observed aloft while near surface temperatures over the ice remained near melting. In the surface inversion dense fog formed that enhanced the downward longwave radiation. Together with a downward turbulent sensible heat flux this caused a rapid melt in this area.

  17. 10 CFR 431.72 - Definitions concerning commercial warm air furnaces.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Definitions concerning commercial warm air furnaces. 431.72 Section 431.72 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR...) characteristics that affect energy consumption, energy efficiency, water consumption, or water...

  18. 10 CFR 431.72 - Definitions concerning commercial warm air furnaces.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Definitions concerning commercial warm air furnaces. 431.72 Section 431.72 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR...) characteristics that affect energy consumption, energy efficiency, water consumption, or water...

  19. Total environmental warming impact (TEWI) calculations for alternative automative air-conditioning systems

    SciTech Connect

    Sand, J.R.; Fischer, S.K.

    1997-01-01

    The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and questions about the effects of refrigerants on global warming. Automobile air-conditioning has three separate impacts on global warming; (1) the effects of refrigerant inadvertently released to the atmosphere from accidents, servicing, and leakage; (2) the efficiency of the cooling equipment (due to the emission of C0{sub 2} from burning fuel to power the system); and (3) the emission of C0{sub 2} from burning fuel to transport the system. The Total Equivalent Warming Impact (TEWI) is an index that should be used to compare the global warming effects of alternative air-conditioning systems because it includes these contributions from the refrigerant, cooling efficiency, and weight. This paper compares the TEWI of current air-conditioning systems using HFC-134a with that of transcritical vapor compression system using carbon dioxide and systems using flammable refrigerants with secondary heat transfer loops. Results are found to depend on both climate and projected efficiency of C0{sub 2}systems. Performance data on manufacturing prototype systems are needed to verify the potential reductions in TEWI. Extensive field testing is also required to determine the performance, reliability, and ``serviceability`` of each alternative to HFC-134a to establish whether the potential reduction of TEWI can be achieved in a viable consumer product.

  20. Crowdsourcing urban air temperatures from smartphone battery temperatures

    NASA Astrophysics Data System (ADS)

    Overeem, A.; Robinson, J. C. R.; Leijnse, H.; Steeneveld, G. J.; Horn, B. K. P.; Uijlenhoet, R.

    2013-08-01

    Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. A straightforward heat transfer model is employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas.

  1. Amazon Basin climate under global warming: the role of the sea surface temperature.

    PubMed

    Harris, Phil P; Huntingford, Chris; Cox, Peter M

    2008-05-27

    The Hadley Centre coupled climate-carbon cycle model (HadCM3LC) predicts loss of the Amazon rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the atmospheric component of HadCM3LC is used to assess the role of simulated changes in mid-twenty-first century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC, including much of the reduction in Amazon Basin rainfall. This rainfall change is shown to be the combined effect of SSTAs in both the tropical Atlantic and the Pacific, with roughly equal contributions from each basin. The greatest rainfall reduction occurs from May to October, outside of the mature South American monsoon (SAM) season. This dry season response is the combined effect of a more rapid warming of the tropical North Atlantic relative to the south, and warm SSTAs in the tropical east Pacific. Conversely, a weak enhancement of mature SAM season rainfall in response to Atlantic SST change is suppressed by the atmospheric response to Pacific SST. This net wet season response is sufficient to prevent dry season soil moisture deficits from being recharged through the SAM season, leading to a perennial soil moisture reduction and an associated 30% reduction in annual Amazon Basin net primary productivity (NPP). A further 23% NPP reduction occurs in response to a 3.5 degrees C warmer air temperature associated with a global mean SST warming. PMID:18267896

  2. 10 CFR 431.76 - Uniform test method for the measurement of energy efficiency of commercial warm air furnaces.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... efficiency of commercial warm air furnaces. 431.76 Section 431.76 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces Test Procedures § 431.76 Uniform test method for the measurement of energy efficiency...

  3. 10 CFR 431.76 - Uniform test method for the measurement of energy efficiency of commercial warm air furnaces.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... efficiency of commercial warm air furnaces. 431.76 Section 431.76 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces Test Procedures § 431.76 Uniform test method for the measurement of energy efficiency...

  4. 10 CFR 431.76 - Uniform test method for the measurement of energy efficiency of commercial warm air furnaces.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... efficiency of commercial warm air furnaces. 431.76 Section 431.76 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces Test Procedures § 431.76 Uniform test method for the measurement of energy efficiency...

  5. 10 CFR 431.76 - Uniform test method for the measurement of energy efficiency of commercial warm air furnaces.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... efficiency of commercial warm air furnaces. 431.76 Section 431.76 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces Test Procedures § 431.76 Uniform test method for the measurement of energy efficiency...

  6. 10 CFR 431.76 - Uniform test method for the measurement of energy efficiency of commercial warm air furnaces.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... efficiency of commercial warm air furnaces. 431.76 Section 431.76 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Warm Air Furnaces Test Procedures § 431.76 Uniform test method for the measurement of energy efficiency...

  7. Controlled-Temperature Hot-Air Gun

    NASA Technical Reports Server (NTRS)

    Munoz, M. C.

    1986-01-01

    Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

  8. Experimental and theoretical analysis results for high temperature air combustion

    SciTech Connect

    Tanigawa, Tadashi; Morita, Mitsunobu

    1998-07-01

    With Japan's preparation of its Action program to prevent global warming in 1990 and the holding of the United National Conference on Environment and Development (the Earth Summit) in 1992 as a backdrop, reflecting the global effort to protect the environment, a high performance industrial furnace development project was launched in 1993 by the New Energy and Industrial Technology Development Organization (NEDO). This project focuses on the development of a combustion technology which uses air that is preheated to extremely high temperatures (above 1,000 C), heretofore considered impossible. Not only can this technology reduce carbon dioxide emission, thought to cause the greenhouse effect, by over 30%, but it can also reduce nitrogen oxide emission by nearly half. This new technology makes use of the recently-developed high-cycle regenerative heat exchanger, for preheating the furnace air supply. This exchanger preheats air to above 1,000 C, much higher than for conventional furnaces, and then this air is injected with fuel. R and D data have shown that CO{sub 2} and NO{sub x} emissions can be reduced markedly. However, the theoretical analysis is yet to be made, thereby hampering efforts to have this advanced technology become widely adopted. This project accumulated new data related to uniform temperature distribution, high energy heat transfer and low NO{sub x} as common characteristics of high temperature air combustion.

  9. Geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppälä, A.; Randall, C. E.; Clilverd, M. A.; Rozanov, E.; Rodger, C. J.

    2009-10-01

    Here we use the ERA-40 and ECMWF operational surface level air temperature data sets from 1957 to 2006 to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the A p index. Previous modeling work has suggested that NO x produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in surface air temperatures (SATs). We find that during winter months, polar SATs in years with high A p index are different than in years with low A p index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, depending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings (SSWs) are excluded. We take into account solar irradiance variations, unlike previous analyses of geomagnetic effects in ERA-40 and operational data. Although we cannot conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. We tested our SAT results against variation in the Quasi Biennial Oscillation, the El Niño Southern Oscillation and the Southern Annular Mode. The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode, and we cannot robustly exclude a chance linkage between sea surface temperature variability and geomagnetic activity.

  10. Amplification of Arctic warming by past air pollution reductions in Europe

    NASA Astrophysics Data System (ADS)

    Acosta Navarro, J. C.; Varma, V.; Riipinen, I.; Seland, Ø.; Kirkevåg, A.; Struthers, H.; Iversen, T.; Hansson, H.-C.; Ekman, A. M. L.

    2016-04-01

    The Arctic region is warming considerably faster than the rest of the globe, with important consequences for the ecosystems and human exploration of the region. However, the reasons behind this Arctic amplification are not entirely clear. As a result of measures to enhance air quality, anthropogenic emissions of particulate matter and its precursors have drastically decreased in parts of the Northern Hemisphere over the past three decades. Here we present simulations with an Earth system model with comprehensive aerosol physics and chemistry that show that the sulfate aerosol reductions in Europe since 1980 can potentially explain a significant fraction of Arctic warming over that period. Specifically, the Arctic region receives an additional 0.3 W m-2 of energy, and warms by 0.5 °C on annual average in simulations with declining European sulfur emissions in line with historical observations, compared with a model simulation with fixed European emissions at 1980 levels. Arctic warming is amplified mainly in fall and winter, but the warming is initiated in summer by an increase in incoming solar radiation as well as an enhanced poleward oceanic and atmospheric heat transport. The simulated summertime energy surplus reduces sea-ice cover, which leads to a transfer of heat from the Arctic Ocean to the atmosphere. We conclude that air quality regulations in the Northern Hemisphere, the ocean and atmospheric circulation, and Arctic climate are inherently linked.

  11. Spatial variability in subsurface warming over the last three decades; insight from repeated borehole temperature measurements in The Netherlands

    NASA Astrophysics Data System (ADS)

    Kooi, Henk

    2008-06-01

    Subsurface temperatures around the world are changing in response to accelerated surface atmospheric temperature (SAT) rise, but are also impacted by other natural and anthropogenic changes in surface environmental conditions which alter the surface energy balance. Improved understanding of the latter influences is important for geothermal climate applications and to generate a comprehensive knowledge-framework of subsurface warming, including inherent spatial variability. Here I examine sixteen wells in a relatively small area in The Netherlands, each with two available temperature logs recorded some three decades apart. Temperature differences of the log pairs reveal marked differences in subsurface warming amongst the wells for this time period. Forward modelling of the observed temperature changes, using surface air temperature (SAT) forcing, shows that a considerable part of this inter-site variability may be caused by inter-site differences in thermal properties and groundwater flow conditions. However, for some of the wells these factors are insufficient, implying contributions from non-SAT-driven changes in ground surface temperature (GST). In one case an anomalous decrease in GST can be linked to back-growth of the canopy after forest cutting. For another well site, GST warming has been less than SAT warming in the absence of apparent changes in surface conditions, indicating local, subtle influences on the surface energy balance independent of SAT. The results demonstrate that repeated borehole temperature logging resolves key uncertainties and ambiguities pertaining to interpretation of individual temperature logs. The study further highlights the importance of establishing high-quality borehole temperature databases, also for these relatively complex settings with dynamic and variable surface conditions.

  12. Air separation with temperature and pressure swing

    DOEpatents

    Cassano, Anthony A.

    1986-01-01

    A chemical absorbent air separation process is set forth which uses a temperature swing absorption-desorption cycle in combination with a pressure swing wherein the pressure is elevated in the desorption stage of the process.

  13. Crowdsourcing urban air temperature measurements using smartphones

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-10-01

    Crowdsourced data from cell phone battery temperature sensors could be used to contribute to improved real-time, high-resolution air temperature estimates in urban areas, a new study shows. Temperature observations in cities are in some cases currently limited to a few weather stations, but there are millions of smartphone users in many cities. The batteries in cell phones have temperature sensors to avoid damage to the phone.

  14. Nowcasting daily minimum air and grass temperature

    NASA Astrophysics Data System (ADS)

    Savage, M. J.

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  15. Nowcasting daily minimum air and grass temperature.

    PubMed

    Savage, M J

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient (b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  16. The use of warm air stream for solvent evaporation: effects on the durability of resin-dentin bonds.

    PubMed

    Reis, Alessandra; Klein-Júnior, Celso A; de Souza, Fabio H Coelho; Stanislawczuk, Rodrigo; Loguercio, Alessandro D

    2010-01-01

    This study evaluated the effect of a warm (W) or cold (C) air-dry stream for solvent evaporation on the immediate (IM) and six-month (6M) resin-dentin bond strength (microTBS) and silver nitrate uptake pattern (SNU) of two-step etch-and-rinse adhesive system (Adper Single Bond [SB] and Prime & Bond 2.1 [PB]). The adhesives were applied on demineralized dentin surfaces and a warm or cold air-dry stream (10 seconds) was applied followed by light-activation (10 seconds). After 24-hours of water storage, the specimens were serially sectioned in the "x" and "y" directions to obtain bonded sticks around 0.8 mm2 to be tested immediately or after six months of water storage. The specimens at each period were immersed in a 50% solution of silver nitrate, photodeveloped and analyzed by SEM for SNU. Higher IM microTBS values were observed for SB under W conditions. Both adhesives showed reductions in microTBS after 6M in both air temperatures. Regarding SEM, a low silver nitrate uptake was observed in the W groups either in IM or 6M for both adhesives. PMID:20166408

  17. Temperature Tunable Air-Gap Etalon Filter

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Stephen, Mark A.; Lunt, David L.

    1998-01-01

    We report on experimental measurements of a temperature tuned air-gap etalon filter. The filter exhibits temperature dependent wavelength tuning of 54 pm/C. It has a nominal center wavelength of 532 nm. The etalon filter has a 27 pm optical bandpass and 600 pm free spectral range (finesse approximately 22). The experimental results are in close agreement with etalon theory.

  18. The time of day effects of warm temperature on flowering time involve PIF4 and PIF5

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To probe the signaling pathways that promote early flowering under warm temperatures, the flowering time of Arabidopsis thaliana plants was evaluated in day-neutral photocycles that had warm temperature (28°C) added during the day, night, or both. Warm temperature present during any part of the phot...

  19. Undulator Hall Air Temperature Fault Scenarios

    SciTech Connect

    Sevilla, J.; Welch, J.; /SLAC

    2010-11-17

    Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about {+-}2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

  20. Modeling monthly mean air temperature for Brazil

    NASA Astrophysics Data System (ADS)

    Alvares, Clayton Alcarde; Stape, José Luiz; Sentelhas, Paulo Cesar; de Moraes Gonçalves, José Leonardo

    2013-08-01

    Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant ( α ≤ 0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67 × 108 pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories.

  1. Effect of warming with temperature oscillations on a low-latitude aphid, Aphis craccivora.

    PubMed

    Chen, Chia-Yu; Chiu, Ming-Chih; Kuo, Mei-Hwa

    2013-08-01

    To estimate the net effect of climate change on natural populations, we must take into account the positive and negative effects of temperature oscillations and climate variability. Warming because of climate change will likely exceed the physiological optima of tropical insects, which currently live very close to their thermal optima. Tropical insects will be negatively affected if their optima are exceeded otherwise warming may affect them positively. We evaluate the demographic responses of the cowpea aphid, Aphis craccivora, to summer warming in subtropical and tropical Taiwan, and examine the effects of diel temperature oscillation on these responses. Aphids were reared at four temperatures (current summer mean, +1.4, +3.9 and +6.4 °C), the latter three simulating different levels of warming. At each average temperature, aphids experienced constant or oscillating (from -2.9 to +3.6 °C of each mean temperature) regimes. As the simulated summer temperatures increased, so did the negative effects on life-history traits and demographic parameters. Compared with aphids reared in constant temperatures, aphids reared in oscillating temperatures developed more slowly and had a longer mean generation time, but their net reproductive rate was higher. These findings demonstrate that climate warming will affect demographic parameters and life-history traits differentially. Studies that use constant temperatures are unlikely to accurately predict biotic responses to climate change. PMID:23448233

  2. On the association between high temperature and mortality in warm climates.

    PubMed

    El-Zein, Abbas; Tewtel-Salem, Mylene

    2005-05-01

    We conducted a time-series analysis of 1997-1999 data records of air temperature and all-cause mortality in Greater Beirut, using bi-linear Poisson auto-regressive models, and published our findings in the Science of the Total Environment [El-Zein, A., Tewtel-Salem, M., Nehme, G., 2004. A time-series analysis of mortality and air temperature in Greater Beirut. Sci. Total Environ. 330, 71-80]. We compared our results to those of Curriero et al. [Curriero, F.C., Heiner, K.S., Samet, J.M., Zeger, S.L., Strug, L., Patz, J.A., 2002. Temperature and mortality in 11 cities of the Eastern United States. Am. J. Epidemiol. 155(1) 80-87.], who subsequently reported that their original results were inaccurate and published new results [Curriero, F.C., Heiner, K.S., Samet, J.M., Zeger, S.L., Strug, L., Patz, J.A., 2002. Temperature and mortality in 11 cities of the Eastern United States. Am. J. Epidemiol. 155(1) 80-87; Curriero, F.C., Samet, J.M., Zeger, S.L., 2003. Letter to the Editor re. On the Use of Generalized Additive Models in Time-Series Studies of Air Pollution and Health" and "Temperature and Mortality in 11 Cities of the Eastern United States". Am. J. Epidemiol. 158(1) 93-94.]. In this letter, we report two changes in the interpretation of our findings as a result of the change in the results of Curriero et al. [Curriero, F.C., Heiner, K.S., Samet, J.M., Zeger, S.L., Strug, L., Patz, J.A., 2002. Temperature and mortality in 11 cities of the Eastern United States. Am. J. Epidemiol. 155(1) 80-87]. Their newly-reported results reinforce our conclusion that heat-related mortality can be a significant public health issue even in temperate to warm climates. However, our findings raise a question concerning the ability of socioeconomic indicators to explain differences in vulnerability to heat between high-income and low-income countries. PMID:15862851

  3. Photosynthetic enhancement by elevated CO₂ depends on seasonal temperatures for warmed and non-warmed Eucalyptus globulus trees.

    PubMed

    Quentin, A G; Crous, K Y; Barton, C V M; Ellsworth, D S

    2015-11-01

    Arguments based on the biochemistry of photosynthesis predict a positive interaction between elevated atmospheric [CO2] and temperature on photosynthesis as well as growth. In contrast, few long-term studies on trees find greater stimulation of photosynthesis in response to elevated [CO2] at warmer compared with cooler temperatures. To test for CO2 × temperature interactions on leaf photosynthesis and whole-plant growth, we planted Eucalyptus globulus Labill. in climate-controlled chambers in the field at the Hawkesbury Forest Experiment research site, and investigated how photosynthetic enhancement changed across a range of seasonal temperatures. Trees were grown in a complete two-way factorial design with two CO2 concentrations (ambient and ambient + 240 ppm) and two temperatures (ambient and ambient + 3 °C) for 15 months until they reached ∼10 m height, after which they were harvested for biomass. There was significant enhancement of photosynthesis and growth with elevated [CO2], with the photosynthetic stimulation varying with season, but there was no significant effect of warming. Photosynthetic enhancement was higher in summer (+46% at 28 °C) than in winter (+14% at 20 °C). Photosynthetic enhancement as a function of leaf temperature was consistent with theoretical expectations, but was strongly mediated by the intercellular [CO2]/ambient [CO2] (Ci/Ca) ratio across seasons. Total tree biomass after 15 months was 66% larger in elevated CO2 (P = 0.017) with no significant warming effect detected. The fraction of biomass in coarse roots was reduced in warmed trees compared with ambient temperature controls, but there was no evidence of changed biomass allocation patterns in elevated CO2. We conclude that there are strong and consistent elevated CO2 effects on photosynthesis and biomass of E. globulus. It is crucial to consider stomatal conductance under a range of conditions to appraise the interactive effect of [CO2] and temperature on

  4. Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

    NASA Astrophysics Data System (ADS)

    Wang, K.; Li, Y.; Wang, X.; Yuan, M.

    2013-12-01

    Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

  5. Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures

    NASA Astrophysics Data System (ADS)

    Cowtan, Kevin; Hausfather, Zeke; Hawkins, Ed; Jacobs, Peter; Mann, Michael E.; Miller, Sonya K.; Steinman, Byron A.; Stolpe, Martin B.; Way, Robert G.

    2015-08-01

    The level of agreement between climate model simulations and observed surface temperature change is a topic of scientific and policy concern. While the Earth system continues to accumulate energy due to anthropogenic and other radiative forcings, estimates of recent surface temperature evolution fall at the lower end of climate model projections. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. Applying the methodology of the HadCRUT4 record to climate model temperature fields accounts for 38% of the discrepancy in trend between models and observations over the period 1975-2014.

  6. Decadal power in land air temperatures: Is it statistically significant?

    NASA Astrophysics Data System (ADS)

    Thejll, Peter A.

    2001-12-01

    The geographical distribution and properties of the well-known 10-11 year signal in terrestrial temperature records is investigated. By analyzing the Global Historical Climate Network data for surface air temperatures we verify that the signal is strongest in North America and is similar in nature to that reported earlier by R. G. Currie. The decadal signal is statistically significant for individual stations, but it is not possible to show that the signal is statistically significant globally, using strict tests. In North America, during the twentieth century, the decadal variability in the solar activity cycle is associated with the decadal part of the North Atlantic Oscillation index series in such a way that both of these signals correspond to the same spatial pattern of cooling and warming. A method for testing statistical results with Monte Carlo trials on data fields with specified temporal structure and specific spatial correlation retained is presented.

  7. Abrupt summer warming and changes in temperature extremes over Northeast Asia since the mid-1990s: Drivers and physical processes

    NASA Astrophysics Data System (ADS)

    Dong, Buwen; Sutton, Rowan T.; Chen, Wei; Liu, Xiaodong; Lu, Riyu; Sun, Ying

    2016-09-01

    This study investigated the drivers and physical processes for the abrupt decadal summer surface warming and increases in hot temperature extremes that occurred over Northeast Asia in the mid-1990s. Observations indicate an abrupt increase in summer mean surface air temperature (SAT) over Northeast Asia since the mid-1990s. Accompanying this abrupt surface warming, significant changes in some temperature extremes, characterized by increases in summer mean daily maximum temperature (Tmax), daily minimum temperature (Tmin), annual hottest day temperature (TXx), and annual warmest night temperature (TNx) were observed. There were also increases in the frequency of summer days (SU) and tropical nights (TR). Atmospheric general circulation model experiments forced by changes in sea surface temperature (SST)/sea ice extent (SIE), anthropogenic greenhouse gas (GHG) concentrations, and anthropogenic aerosol (AA) forcing, relative to the period 1964-93, reproduced the general patterns of observed summer mean SAT changes and associated changes in temperature extremes, although the abrupt decrease in precipitation since the mid-1990s was not simulated. Additional model experiments with different forcings indicated that changes in SST/SIE explained 76% of the area-averaged summer mean surface warming signal over Northeast Asia, while the direct impact of changes in GHG and AA explained the remaining 24% of the surface warming signal. Analysis of physical processes indicated that the direct impact of the changes in AA (through aerosol-radiation and aerosol-cloud interactions), mainly related to the reduction of AA precursor emissions over Europe, played a dominant role in the increase in TXx and a similarly important role as SST/SIE changes in the increase in the frequency of SU over Northeast Asia via AA-induced coupled atmosphere-land surface and cloud feedbacks, rather than through a direct impact of AA changes on cloud condensation nuclei. The modelling results also imply

  8. No Evidence for Recent Climatic Warming From Borehole Temperatures in the Canadian Cordillera

    NASA Astrophysics Data System (ADS)

    Lewis, T.

    2004-05-01

    Inversions of temperature data from 60 boreholes at 20 sites spanning 13 degrees of latitude in the Canadian Cordillera show that there was no significant unexplained change in the GST (ground surface temperature) over the last two centuries. There were no changes in the GST at undisturbed sites, and at sites where a known event altered the terrain surrounding them, the modelled changes in GST were in agreement with the site histories. These boreholes were chosen for analysis from over 500 in this region in the GSC data base. The others were excluded because of unknown terrain histories, obvious effects of water flow in crystalline rocks, low water tables, or penetration of sedimentary rocks that might have bulk permeability. From a consideration of the heat budget at the surface of the earth, the change in the average surface temperature expected due to permanent deforestation and/or drainage of surface waters is approximately 2 K. This is due to the greater run off of water and the smaller amount of heat required, principally in the summer time, for evaporation and transpiration. This is equivalent to the average amount detected at such sites. The GST tracks the SAT (surface air temperature) in this region, except when it is below 0° C. Climatic warming in the winter time would not be detected by this method, except in the very southern, coastal part of this region. Proxy data indicate that winter temperatures have not changed significantly in the north. Therefore I suggest changing amounts of precipitation and their distribution in time are causing glacial recession.

  9. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  10. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  11. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  12. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  13. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  14. Sampling Biases in Datasets of Historical Mean Air Temperature over Land

    NASA Astrophysics Data System (ADS)

    Wang, K.

    2014-12-01

    Global mean surface air temperature have risen by 0.74 °C over the last 100 years. However, the definition of mean surface air temperature is still a subject of debate. The most defensible definition might be the integral of the continuous temperature measurements over a day (Td0). However, for technological and historical reasons, mean temperatures (Td1) over land have been taken to be the average of the daily maximum and minimum temperature measurements. All existing principle global temperature analyses over land are primarily based on Td1. Here, I make a first quantitative assessment of the bias in the use of Td1 to estimate trends of mean air temperature using hourly air temperature observations at 5600 globally distributed weather stations from the 1970s to 2013. I find that the use of Td1 has a negligible impact on the global mean warming rate. However, the trend of Td1 has a substantial bias at regional and local scales, with a root mean square error of over 25% at 5°×5° grids. Therefore, caution should be taken when using mean air temperature datasets based on Td1 to examine spatial patterns of global warming.

  15. Effect of Strain Rate and Temperature Gradient on Warm Formability of Aluminum Alloy Sheet

    NASA Astrophysics Data System (ADS)

    Bagheriasl, R.; Ghavam, K.; Worswick, M. J.

    2011-08-01

    The effect of temperature gradient and forming speed on warm formability of aluminum alloy sheet has been studied using a coupled thermal mechanical finite element model of cup deep drawing. A user-defined material model was developed using the Bergstrom temperature and strain-rate dependant hardening model and Barlat YLD2000 anisotropic yield surface, which was implemented within LS-DYNA. The stress-strain curves for AA3003 at elevated temperatures and different strain rates were used to fit the Bergstrom hardening parameters. The anisotropy parameters were considered to be non-temperature dependant. The numerical model was validated against experiments from previous work and was found to accurately predict punch force for warm deep drawing. Increases in forming speed are shown to have a negative effect on formability. It is concluded that non-isothermal warm forming can be used to improve the formability of aluminum alloy sheet.

  16. Persistence analysis of daily mean air temperature variation in Georgia

    NASA Astrophysics Data System (ADS)

    Matcharashvili, Teimuraz; Chelidze, Tamaz; Zhukova, Natalia; Mepharidze, Ekaterine; Sborshchikov, Alexander

    2010-05-01

    Extrapolation of observed linear trends is common practice in climate change researches on different scales. In this respect it is important, that though global warming is well established, the question of persistence of trends on regional scales remain controversial. Indeed, climate change for specific region and time by definition includes more than the simple average of weather conditions. Either random events or long-term changes, or more often combinations of them, can bring about significant swings in a variety of climate indicators from one time period to the next. Therefore in order to achieve further understanding of dynamics of climate change the character of stable peculiarities of analyzed dynamics should be investigated. Analysis of the character of long range correlations in climatological time series or peculiarities of their inherent memory is motivated exactly by this goal. Such analysis carried out on a different scales may help to understand spatial and temporal features of regional climate change. In present work the problem of persistence of observed trends in air temperature time series in Georgia was investigated. Longest available mean daily temperature time series of Tbilisi (1890-2008) were analyzed. Time series on shorter time scales of five stations in the West and East Georgia also were considered as well as monthly mean temperature time series of five stations. Additionally, temporally and spatially averaged daily and monthly mean air temperature time series were analyzed. Extent of persistence in mentioned time series were evaluated using R/S analysis calculation. Detrended and Multifractal Detrended Fluctuation Analysis as well as multi scaling analysis based on CWT have been used. Our results indicate that variation of daily or monthly mean temperatures reveals clear antipersistence on whole available time scale. It seems that antipersistence on global scale is general characteristics of mean air temperature variation and is not

  17. Responses of soil respiration to elevated CO2, air warming, and changing soil water availability in an old-field grassland

    SciTech Connect

    Wan, Shiqiang; Norby, Richard J; Childs, Joanne; Weltzin, Jake

    2007-01-01

    Responses of soil respiration to atmospheric and climatic change will have profound impacts on ecosystem and global C cycling in the future. This study was conducted to examine effects on soil respiration of the concurrent driving factors of elevated atmospheric CO2 concentration, rising temperature, and changing precipitation in a constructed old-field grassland in eastern Tennessee, USA. Model ecosystems of seven old-field species in 12 open-top chambers (4 m in diameter) were treated with two CO2 (ambient and ambient plus 300 ppm) and two temperature (ambient and ambient plus 3 C) levels. Two split plots with each chamber were assigned with high and low soil moisture levels. During the 19-month experimental period from June 2003 to December 2004, higher CO2 concentration and soil water availability significantly increased mean soil respiration by 35.8% and 15.7%, respectively. The effects of air warming on soil respiration varied seasonally from small reductions to significant increases to no response, and there was no significant main effect. In the wet side of elevated CO2 chambers, air warming consistently caused increases in soil respiration, whereas in other three combinations of CO2 and water treatments, warming tended to decrease soil respiration over the growing season but increase it over the winter. There were no interactive effects on soil respiration among any two or three treatment factors irrespective of testing time period. Temperature sensitivity of soil respiration was reduced by air warming, lower in the wet than the dry side, and not affected by CO2 treatment. Variations of soil respiration responses with soil temperature and soil moisture ranges could be primarily attributable to the seasonal dynamics of plant growth and its responses to the three treatments. Using a conceptual model to interpret the significant relationships of treatment-induced changes in soil respiration with changes in soil temperature and moisture observed in this study

  18. Warm Body Temperature Facilitates Energy Efficient Cortical Action Potentials

    PubMed Central

    Yu, Yuguo; Hill, Adam P.; McCormick, David A.

    2012-01-01

    The energy efficiency of neural signal transmission is important not only as a limiting factor in brain architecture, but it also influences the interpretation of functional brain imaging signals. Action potential generation in mammalian, versus invertebrate, axons is remarkably energy efficient. Here we demonstrate that this increase in energy efficiency is due largely to a warmer body temperature. Increases in temperature result in an exponential increase in energy efficiency for single action potentials by increasing the rate of Na+ channel inactivation, resulting in a marked reduction in overlap of the inward Na+, and outward K+, currents and a shortening of action potential duration. This increase in single spike efficiency is, however, counterbalanced by a temperature-dependent decrease in the amplitude and duration of the spike afterhyperpolarization, resulting in a nonlinear increase in the spike firing rate, particularly at temperatures above approximately 35°C. Interestingly, the total energy cost, as measured by the multiplication of total Na+ entry per spike and average firing rate in response to a constant input, reaches a global minimum between 37–42°C. Our results indicate that increases in temperature result in an unexpected increase in energy efficiency, especially near normal body temperature, thus allowing the brain to utilize an energy efficient neural code. PMID:22511855

  19. Understanding the rapid summer warming and changes in temperature extremes since the mid-1990s over Western Europe

    NASA Astrophysics Data System (ADS)

    Dong, Buwen; Sutton, Rowan T.; Shaffrey, Len

    2016-05-01

    Analysis of observations indicates that there was a rapid increase in summer (June-August) mean surface air temperature (SAT) since the mid-1990s over Western Europe. Accompanying this rapid warming are significant increases in summer mean daily maximum temperature, daily minimum temperature, annual hottest day temperature and warmest night temperature, and an increase in frequency of summer days and tropical nights, while the change in the diurnal temperature range (DTR) is small. This study focuses on understanding causes of the rapid summer warming and associated temperature extreme changes. A set of experiments using the atmospheric component of the state-of-the-art HadGEM3 global climate model have been carried out to quantify relative roles of changes in sea surface temperature (SST)/sea ice extent (SIE), anthropogenic greenhouse gases (GHGs), and anthropogenic aerosols (AAer). Results indicate that the model forced by changes in all forcings reproduces many of the observed changes since the mid-1990s over Western Europe. Changes in SST/SIE explain 62.2 ± 13.0 % of the area averaged seasonal mean warming signal over Western Europe, with the remaining 37.8 ± 13.6 % of the warming explained by the direct impact of changes in GHGs and AAer. Results further indicate that the direct impact of the reduction of AAer precursor emissions over Europe, mainly through aerosol-radiation interaction with additional contributions from aerosol-cloud interaction and coupled atmosphere-land surface feedbacks, is a key factor for increases in annual hottest day temperature and in frequency of summer days. It explains 45.5 ± 17.6 % and 40.9 ± 18.4 % of area averaged signals for these temperature extremes. The direct impact of the reduction of AAer precursor emissions over Europe acts to increase DTR locally, but the change in DTR is countered by the direct impact of GHGs forcing. In the next few decades, greenhouse gas concentrations will continue to rise and AAer precursor

  20. Temperature alone does not explain phenological variation of diverse temperate plants under experimental warming.

    PubMed

    Marchin, Renée M; Salk, Carl F; Hoffmann, William A; Dunn, Robert R

    2015-08-01

    Anthropogenic climate change has altered temperate forest phenology, but how these trends will play out in the future is controversial. We measured the effect of experimental warming of 0.6-5.0 °C on the phenology of a diverse suite of 11 plant species in the deciduous forest understory (Duke Forest, North Carolina, USA) in a relatively warm year (2011) and a colder year (2013). Our primary goal was to dissect how temperature affects timing of spring budburst, flowering, and autumn leaf coloring for functional groups with different growth habits, phenological niches, and xylem anatomy. Warming advanced budburst of six deciduous woody species by 5-15 days and delayed leaf coloring by 18-21 days, resulting in an extension of the growing season by as much as 20-29 days. Spring temperature accumulation was strongly correlated with budburst date, but temperature alone cannot explain the diverse budburst responses observed among plant functional types. Ring-porous trees showed a consistent temperature response pattern across years, suggesting these species are sensitive to photoperiod. Conversely, diffuse-porous species responded differently between years, suggesting winter chilling may be more important in regulating budburst. Budburst of the ring-porous Quercus alba responded nonlinearly to warming, suggesting evolutionary constraints may limit changes in phenology, and therefore productivity, in the future. Warming caused a divergence in flowering times among species in the forest community, resulting in a longer flowering season by 10-16 days. Temperature was a good predictor of flowering for only four of the seven species studied here. Observations of interannual temperature variability overpredicted flowering responses in spring-blooming species, relative to our warming experiment, and did not consistently predict even the direction of flowering shifts. Experiments that push temperatures beyond historic variation are indispensable for improving predictions of

  1. Robust Comparison of Climate Models with Observations Using Blended Land Air and Ocean Sea Surface Temperatures

    NASA Astrophysics Data System (ADS)

    Hausfather, Z.; Jacobs, P.; Cowtan, K.; Hawkins, E.; Mann, M. E.; Miller, S. K.; Steinman, B. A.; Way, R. G.; Stolpe, M.

    2015-12-01

    Model-observation comparisons provide an important test of climate models' ability to realistically simulate the transient evolution of the system. A great deal of attention has recently focused on the so-called "hiatus" period of the past ~15 years, when estimates of recent surface temperature evolution fall at the lower end of climate model projections. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. We discuss the magnitude of these biases, and their implications for the evaluation of climate model performance over the "hiatus" period and the full instrumental record.

  2. The paradox of cooling streams in a warming world: regional climate trends do not parallel variable local trends in stream temperature in the Pacific continental United States

    USGS Publications Warehouse

    Arismendi, Ivan; Johnson, Sherri; Dunham, Jason B.; Haggerty, Roy; Hockman-Wert, David

    2012-01-01

    Temperature is a fundamentally important driver of ecosystem processes in streams. Recent warming of terrestrial climates around the globe has motivated concern about consequent increases in stream temperature. More specifically, observed trends of increasing air temperature and declining stream flow are widely believed to result in corresponding increases in stream temperature. Here, we examined the evidence for this using long-term stream temperature data from minimally and highly human-impacted sites located across the Pacific continental United States. Based on hypothesized climate impacts, we predicted that we should find warming trends in the maximum, mean and minimum temperatures, as well as increasing variability over time. These predictions were not fully realized. Warming trends were most prevalent in a small subset of locations with longer time series beginning in the 1950s. More recent series of observations (1987-2009) exhibited fewer warming trends and more cooling trends in both minimally and highly human-influenced systems. Trends in variability were much less evident, regardless of the length of time series. Based on these findings, we conclude that our perspective of climate impacts on stream temperatures is clouded considerably by a lack of long-termdata on minimally impacted streams, and biased spatio-temporal representation of existing time series. Overall our results highlight the need to develop more mechanistic, process-based understanding of linkages between climate change, other human impacts and stream temperature, and to deploy sensor networks that will provide better information on trends in stream temperatures in the future.

  3. Measurements of surface air temperatures in Lombok with low cost miniature data loggers

    NASA Astrophysics Data System (ADS)

    Sudiarta, I. W.; Yadnya, M. S.; Mardiana, L.; Kuripan, I. N.

    2014-09-01

    The global warming and climate change are two of our major problems in this decade. Local impacts of global warming need to be investigated since it depends on local conditions. Understanding variability of local weather especially surface air temperature requires many observations, not only periodic but also covers large area. In this paper, we report our progress in developing low cost miniature data loggers for temperature measurements. The data loggers are based on microcontrollers ATMega8L and 10 kΩ thermistors. Calibration results in laboratory and in field have indicated that the temperature obtained by data loggers shows good agreement with thermometer readings. It is found that errors of temperature measurements are less than 0.3 °C. We have performed preliminary temperature measurements in Lombok Island using twenty data loggers for about one week duration. Temperature variation in Lombok shows localized temperature distribution that is affected by position and topography.

  4. Precipitation scaling with temperature in warm and cold climates: An analysis of CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Li, Guangqi; Harrison, Sandy P.; Bartlein, Patrick J.; Izumi, Kenji; Colin Prentice, I.

    2013-08-01

    investigate the scaling between precipitation and temperature changes in warm and cold climates using six models that have simulated the response to both increased CO2 and Last Glacial Maximum (LGM) boundary conditions. Globally, precipitation increases in warm climates and decreases in cold climates by between 1.5%/°C and 3%/°C. Precipitation sensitivity to temperature changes is lower over the land than over the ocean and lower over the tropical land than over the extratropical land, reflecting the constraint of water availability. The wet tropics get wetter in warm climates and drier in cold climates, but the changes in dry areas differ among models. Seasonal changes of tropical precipitation in a warmer world also reflect this "rich get richer" syndrome. Precipitation seasonality is decreased in the cold-climate state. The simulated changes in precipitation per degree temperature change are comparable to the observed changes in both the historical period and the LGM.

  5. Linking geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppala, Annika

    ERA-40 and ECMWF operational surface level air temperature (SAT) data sets from 1957 to 2006 were used to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the Ap index. Previous modelling work has suggested that NOx produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in polar SATs. We find that during winter months, ERA-40 and ECMWF polar SATs in years with high Ap index are different than in years with low Ap index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, de-pending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings are excluded. Solar irradiance variations were taken into account in the analysis. Although using the re-analysis and operational data sets it was not possible to conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating polar wintertime surface air temperature patterns. The SAT results were tested against variation in the Quasi Biennial Oscillation (QBO), the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode n (SAM). The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode (NAM) and we could not robustly exclude a chance linkage between sea surface temperature (SST) variability and geomagnetic activity. Examining the physical link between geomagnetic activity and polar surface temperature variability patterns using atmospheric models is an ongoing task.

  6. Long term temperature sensitivity of soil carbon pools in a prairie warming experiment

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Brennan, A. L.; Pendall, E.

    2012-12-01

    The temperature sensitivity of microbial respiration fluxes of CO2 from soil is a critical determinant of soil carbon stocks in a warming climate. While short-term effects of temperature on soil microbial metabolism are well known, the effects of warming on longer-lived soil carbon pools and under the altered substrate conditions that result from warming are less well understood, and critical to predicting future soil carbon stocks. We used a combination of carbon isotopes and experimental treatments to examine the temperature sensitivity of soil C pools of different ages. We sampled soils from the Wyoming Prairie Heating and CO2 Enrichment (PHACE) experiment, where addition of a carbon isotope tracer in elevated CO2 plots allowed us to separate the effect of temperature on respiration of C fixed prior to the experiment (> 5 years old) from carbon fixed more recently. We incubated soils at three temperatures in the laboratory to compare the temperature sensitivity of soil carbon pools from a combination of field treatments; vegetated vs. non-vegetated, and field warmed vs. ambient temperature. For the vegetated treatment, C residing in soil for at least 5 years (fixed prior to the experiment) contributed less than 10% of the total CO2 flux, with the majority of CO2 coming from soil C deposited more recently. However, pre-experiment C was about twice as temperature sensitive as newer C. In contrast, there was no difference in the temperature sensitivity of pre-experiment and younger C from the non-vegetated plots, where application of herbicide prevented new plant inputs for 4 growing seasons previous. A field warming treatment allowed us to investigate the effect of labile C depletion on temperature sensitivity. Specifically, field warmed soils were more substrate-depleted, with lower CO2 fluxes, and ~2/3 of respiration coming from pre-experiment C, compared to ~1/4 from the ambient temperature control. Despite the relative depletion of labile substrate

  7. Evidence for a little ice age and recent warming from a borehole temperature data inversion procedure

    SciTech Connect

    Fivez, J.; Thoen, J.

    2004-11-15

    In this article, we apply our analytical theory, published earlier in this journal, to obtain information on the earth surface temperature history from some borehole temperature data. Compared to the results of the five different methods applied to the same temperature data, our method seems to be easier, assumption-free, and yields internally consistent results. The results suggest a cooling a few centuries ago, followed by a continuing warming up to these days, in agreement with a little ice age scenario.

  8. Design and performance of B4WarmED, an aboveground and belowground free-air warming experiment at the temperate-boreal forest ecotone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conducting manipulative climate change experiments in forests is challenging, given their spatial heterogeneity and canopy complexity. One specific challenge involves warming both plants and soils to depth in ecosystems without much bare ground. We describe the design, implementation, and performanc...

  9. Energy and global warming impacts of next generation refrigeration and air conditioning technologies

    SciTech Connect

    Sand, J.R.; Fischer, S.K.; Baxter, V.D.

    1996-10-01

    Significant developments have occurred in hydrofluorocarbon (HFC) and the application of ammonia and hydrocarbons as refrigerant working fluids since the original TEWI (Total Equivalent Warming Impact) report in 1991. System operating and performance data on alternative refrigerants and refrigeration technologies justify and updated evaluation of these new alternative refrigerants and competing technologies in well-characterized applications. Analytical and experimental results are used to show quantitative comparisons between HFCS, HFC blends, hydrocarbons, and ammonia, used as refrigerants. An objective evaluation is presented for commercial and near commercial non-CFC refrigerants/blowing agents and alternative refrigeration technologies. This information is needed for objective and quantitative decisions on policies addressing greenhouse gas emissions from refrigeration and air conditioning equipment. The evaluation assesses the energy use and global warming impacts of refrigeration and air conditioning technologies that could be commercialized during the phase out of HCFCS. Quantitative comparison TEWI for two application areas are presented. Opportunities for significant reductions in TEWI are seen with currently known refrigerants through improved maintenance and servicing practices and improved product designs.

  10. Wood anatomical responses of oak saplings exposed to air warming and soil drought.

    PubMed

    Fonti, P; Heller, O; Cherubini, P; Rigling, A; Arend, M

    2013-01-01

    Water is vital for plant performance and survival. Its scarcity, induced by a seasonal decline in soil water availability or an increase of evaporative demand, can cause failures of the water conducting system. An adequate tolerance to drought and the ability to acclimate to changing hydraulic conditions are important features for the survival of long-lived woody plants in dry environments. In this study we examine secondary growth and xylem anatomical acclimation of 6 year old saplings of three European oak species (Quercus robur, Q. petraea, Q. pubescens) during the third consecutive year of exposure to soil drought and/or air warming (from 2007 to 2009). Intra-annual pinning was applied to mark the development of the formation of the annual ring 2009. Vessel size, parenchyma cell density and fiber size produced at different time of the growing season 2009 were compared between drought and warming treatments and species. Drought reduced secondary growth and induced changes in xylem structure while air warming had little effect on wood anatomical traits. Results indicate that drought-exposed saplings adjust their xylem structure to improve resistance and repairing abilities after cavitation. All species show a significant radial growth reduction, a reduced vessel size with diminished conductivity and a slightly increased density of parenchyma cells. Comparisons between species fostered our understanding of the relationship between the inter-specific xylem hydraulic plasticity and the ecological response to drought. The stronger changes observed for Q. robur and Q. petraea indicate a lower drought tolerance than Q. pubescens. PMID:22612857

  11. Troposphere-Stratosphere Coupled Chemistry-Climate Interactions: From Global Warming Projections to Air Quality

    NASA Astrophysics Data System (ADS)

    Nowack, P. J.; Abraham, N. L.; Maycock, A. C.; Braesicke, P.; Pyle, J. A.

    2015-12-01

    Changes in stratospheric composition can affect tropospheric composition and vice versa. Of particular interest are trace gas concentrations at the interface between these two atmospheric layers in the tropical upper troposphere and lower stratosphere (UTLS). This is due to the crucial importance of composition changes in the UTLS for the global energy budget. In a recent study (Nowack et al., 2015), we provided further evidence that composition changes in the tropical UTLS can significantly affect global warming projections. Using a state-of-the-art atmosphere-ocean chemistry-climate model, we found a ~20% smaller global warming in response to an abrupt 4xCO2 forcing if composition feedbacks were included in the calculations as compared to simulations in which composition feedbacks were not considered. We attributed this large difference in surface warming mainly to circulation-driven decreases in tropical UTLS ozone and related changes in stratospheric water vapor, partly counteracted by simultaneous changes in ice clouds. Here, we explain why this result is expected to differ between models and how, inter alia, tropospheric chemical mechanisms can contribute to this uncertainty. We highlight that improving our understanding of processes in the tropical UTLS and their representation in Earth system models remains a key challenge in climate research.Finally, taking geoengineering as a new example, we show that changes in the stratosphere can have an impact on air quality in the troposphere. In particular, we explain for a simple solar radiation management scenario how changes in surface ozone can be linked to changes in meteorology and composition in the troposphere and stratosphere. In conclusion, we highlight the importance of considering air quality impacts when evaluating a variety of geoengineering scenarios. Reference: Nowack, P.J., Abraham, N.L., Maycock, A.C., Braesicke, P., Gregory, J.M., Joshi, M.M., Osprey, A., and Pyle, J.A. Nature Climate Change 5, 41

  12. Vulnerability to the mortality effects of warm temperature in the districts of England and Wales

    NASA Astrophysics Data System (ADS)

    Bennett, James E.; Blangiardo, Marta; Fecht, Daniela; Elliott, Paul; Ezzati, Majid

    2014-04-01

    Warm temperatures adversely affect disease occurrence and death, in extreme conditions as well as when the temperature changes are more modest. Therefore climate change, which is expected to affect both average temperatures and temperature variability, is likely to impact health even in temperate climates. Climate change risk assessment is enriched if there is information on vulnerability and resilience to effects of temperature. Some studies have analysed socio-demographic characteristics that make individuals vulnerable to adverse effects of temperature. Less is known about community-level vulnerability. We used geo-coded mortality and environmental data and Bayesian spatial methods to conduct a national small-area analysis of the mortality effects of warm temperature for all 376 districts in England and Wales. In the most vulnerable districts, those in London and south/southeast England, odds of dying from cardiorespiratory causes increased by more than 10% for 1 °C warmer temperature, compared with virtually no effect in the most resilient districts, which were in the far north. A 2 °C warmer summer may result in 1,552 (95% credible interval 1,307-1,762) additional deaths, about one-half of which would occur in 95 districts. The findings enable risk and adaptation analyses to incorporate local vulnerability to warm temperature and to quantify inequality in its effects.

  13. Investigating climatic drivers of the warming hole through empirical downscaling of eastern U.S. summertime maximum temperatures

    NASA Astrophysics Data System (ADS)

    Wagner, Audrey Romaine

    Global average temperatures have increased over the past century, but not all regions of the world have experienced warming. The central United States has experienced less warming than western and eastern portions of the country, with some stations experiencing cooling trends during the period of 1948-2009, leading researchers to dub the area a "warming hole." The causes of this anomaly have been investigated via general circulation models (GCMs) and regional climate model downscaling of GCM output, but conclusions have been limited. This research identifies important drivers of June, July, and August (JJA) mean maximum daily temperature (Tmax) in the region which includes the "warming hole" by developing a model for Tmax using empirical downscaling of large scale variables and local precipitation. First, robust trend analysis is used to determine temperature trends across the country for two time periods: 1948--2009, and 1978--2009; and to locate stations which have experienced cooling, or minimal warming. Second, 19 surface and upper air variables are investigated to identify the optimal independent predictors of Tmax. Station-by-station models of T max are produced from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis sea level pressure, 500 mb geopotential heights, total (meridional and zonal) 850 mb winds in the area of frequent LLJs, as well as station precipitation and assessed for quality. Measures of skill include analysis of error and variance in the modeled time series, as well values of beta-weighted regression coefficients. Third, trends from the modeled time series are calculated and compared with the observed trends. The models show that 500 mb heights have a strong positive correlation with Tmax across the study area, while precipitation widely and uniformly correlates with lower Tmax. Sea level pressure has a negative correlation with Tmax in much of the study area. The LLJ predictor provides novel

  14. The deal with diel: Temperature fluctuations, asymmetrical warming, and ubiquitous metals contaminants.

    PubMed

    Hallman, Tyler A; Brooks, Marjorie L

    2015-11-01

    Climate projections over the next century include disproportionately warmer nighttime temperatures ("asymmetrical warming"). Cool nighttime temperatures lower metabolic rates of aquatic ectotherms. In contaminated waters, areas with cool nights may provide thermal refugia from high rates of daytime contaminant uptake. We exposed Cope's gray tree frogs (Hyla chrysoscelis), southern leopard frogs (Lithobates sphenocephalus), and spotted salamanders (Ambystoma maculatum) to five concentrations of a mixture of cadmium, copper, and lead under three to four temperature regimes, representing asymmetrical warming. At concentrations with intermediate toxicosis at test termination (96 h), temperature effects on acute toxicity or escape distance were evident in all study species. Asymmetrical warming (day:night, 22:20 °C; 22:22 °C) doubled or tripled mortality relative to overall cooler temperatures (20:20 °C) or cool nights (22:18 °C). Escape distances were 40-70% shorter under asymmetrical warming. Results suggest potentially grave ecological impacts from unexpected toxicosis under climate change. PMID:26142755

  15. Warm Pool Temperatures and the Zonal Gradient in the Tropical Pacific during the Early Pliocene Warm Period

    NASA Astrophysics Data System (ADS)

    Ravelo, A. C.; Fedorov, A. V.; Ford, H. L.; Lawrence, K. T.

    2014-12-01

    The absolute temperature of the western Pacific warm pool (WPWP) and the zonal tropical Pacific temperature gradient provide fundamental information regarding the causes of Pliocene warmth and regarding earth system sensitivity when atmospheric CO2 was similar to today (~350-400 ppm). Temperature estimates, derived from foraminiferal Mg/Ca, Uk'37 and TEX86, differ in detail from each other, but overall indicate that, within error, WPWP temperatures were similar to today while the zonal gradient was reduced relative to today. WPWP TEX86 data (Zhang et al., 2014; O'Brien et al., 2014) indicate a long-term cooling from early Pliocene average values similar to today, to approximately 2C cooler during the Late Pleistocene (although calibration errors of ±2.5C exceed the amplitude of the trend). Notably, Late Pleistocene orbital-scale data indicate a strong coupling between WPWP temperature and CO2, which was as much as ~30% lower than pre-industrial values; however, during the early Pliocene, WPWP temperatures were not warmer even though CO2 was as much as ~30% higher that pre-industrial values. Hence, WPWP temperature sensitivity to CO2 forcing was non-linear over myr-long time scales. Orbital scale sensitivity cannot be evaluated in the early Pliocene until more CO2 and temperature records are generated. By compiling data from the eastern tropical Pacific (ETP) it is possible to resolve changes in the spatial pattern of temperature, with the largest anomalies in the heart of the cold tongue. In all, the cold tongue was warmer than today resulting in a reduced (but existent) zonal gradient of about 1-2C, referred to as a 'permanent El Niño-like' or 'El Padre' mean state. Although many temperature proxy records agree with each other, some do not. These apparent disagreements can be explained by considering the depth ecology of organisms that produce the fossil shells and molecules that are analyzed, whole-ocean changes in chemistry, and post-depositional processes.

  16. What caused the recent ``Warm Arctic, Cold Continents'' trend pattern in winter temperatures?

    NASA Astrophysics Data System (ADS)

    Sun, Lantao; Perlwitz, Judith; Hoerling, Martin

    2016-05-01

    The emergence of rapid Arctic warming in recent decades has coincided with unusually cold winters over Northern Hemisphere continents. It has been speculated that this "Warm Arctic, Cold Continents" trend pattern is due to sea ice loss. Here we use multiple models to examine whether such a pattern is indeed forced by sea ice loss specifically and by anthropogenic forcing in general. While we show much of Arctic amplification in surface warming to result from sea ice loss, we find that neither sea ice loss nor anthropogenic forcing overall yield trends toward colder continental temperatures. An alternate explanation of the cooling is that it represents a strong articulation of internal atmospheric variability, evidence for which is derived from model data, and physical considerations. Sea ice loss impact on weather variability over the high-latitude continents is found, however, to be characterized by reduced daily temperature variability and fewer cold extremes.

  17. Trends in Surface Temperature from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.

    2014-12-01

    To address possible causes of the current hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We find a monotonic positive trend for the land temperature but not for the ocean temperature. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The results are compared with the model studies. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  18. Cardinal temperatures for wheat leaf appearance as assessed from varied sowing dates and infrared warming

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate data on crop responses to temperatures are essential for predicting the potential impacts of climate extremes. Air temperatures can be precisely regulated in controlled environment chambers, but chambers seldom provide realistic radiation, photoperiod, wind and humidity regimes, which raise...

  19. Temperature Profiles Along the Root with Gutta-percha Warmed through Different Heat Sources

    PubMed Central

    Simeone, Michele; Santis, Roberto De; Ametrano, Gianluca; Prisco, Davide; Borrelli, Marino; Paduano, Sergio; Riccitiello, Francesco; Spagnuolo, Gianrico

    2014-01-01

    Objectives: To evaluate temperature profiles developing in the root during warm compaction of gutta-percha with the heat sources System B and System MB Obtura (Analityc Technology, Redmond, WA, USA). Thirty extracted human incisor teeth were used. Root canals were cleaned and shaped by means of Protaper rotary files (Dentsply-Maillefer, Belgium), and imaging was performed by micro-CT (Skyscan 1072, Aartselaar, Belgium). Methods: Teeth were instrumented with K-type thermocouples, and the roots were filled with thermoplastic gutta-percha. Vertical compaction was achieved through the heat sources System B and System MB, and temperature profiles were detect-ed by means of NI Dac Interface controlled by the LabView System. With both heat sources, higher temperature levels were recorded in the region of the root far from the apex. When the warm plugger tip was positioned at a distance of 3 mm from the root apex, temperature levels of about 180°C were used to soften gutta-percha, and no statistically significant differences were observed between peak temperatures developed by the two heating sources at the root apex. However, a temperature level higher than 40°C was maintained for a longer time with System MB. Results: Statistically significant differences were observed in peak temperature levels recorded far from the root apex. Thus, with a temperature of about 180°C and the warm plugger positioned at 3 mm from the root apex, both heating sources led to a temperature slightly higher than 40°C at the apex of the root, suggesting that the gutta-percha was properly softened. Significance: A temperature level higher than 40°C was maintained for a longer time with System MB, thus providing an ad-equate time for warm compaction of the gutta-percha. PMID:25614768

  20. Surface air temperature and its changes over the past 150 years

    NASA Astrophysics Data System (ADS)

    Jones, P. D.; New, M.; Parker, D. E.; Martin, S.; Rigor, I. G.

    1999-05-01

    We review the surface air temperature record of the past 150 years, considering the homogeneity of the basic data and the standard errors of estimation of the average hemispheric and global estimates. We present global fields of surface temperature change over the two 20-year periods of greatest warming this century, 1925-1944 and 1978-1997. Over these periods, global temperatures rose by 0.37° and 0.32°C, respectively. The twentieth-century warming has been accompanied by a decrease in those areas of the world affected by exceptionally cool temperatures and to a lesser extent by increases in areas affected by exceptionally warm temperatures. In recent decades there have been much greater increases in night minimum temperatures than in day maximum temperatures, so that over 1950-1993 the diurnal temperature range has decreased by 0.08°C per decade. We discuss the recent divergence of surface and satellite temperature measurements of the lower troposphere and consider the last 150 years in the context of the last millennium. We then provide a globally complete absolute surface air temperature climatology on a 1° × 1° grid. This is primarily based on data for 1961-1990. Extensive interpolation had to be undertaken over both polar regions and in a few other regions where basic data are scarce, but we believe the climatology is the most consistent and reliable of absolute surface air temperature conditions over the world. The climatology indicates that the annual average surface temperature of the world is 14.0°C (14.6°C in the Northern Hemisphere (NH) and 13.4°C for the Southern Hemisphere). The annual cycle of global mean temperatures follows that of the land-dominated NH, with a maximum in July of 15.9°C and a minimum in January of 12.2°C.

  1. Effects of copper, hypoxia and acute temperature shifts on mitochondrial oxidation in rainbow trout (Oncorhynchus mykiss) acclimated to warm temperature.

    PubMed

    Sappal, Ravinder; Fast, Mark; Stevens, Don; Kibenge, Fred; Siah, Ahmed; Kamunde, Collins

    2015-12-01

    Temperature fluctuations, hypoxia and metals pollution frequently occur simultaneously or sequentially in aquatic systems and their interactions may confound interpretation of their biological impacts. With a focus on energy homeostasis, the present study examined how warm acclimation influences the responses and interactions of acute temperature shift, hypoxia and copper (Cu) exposure in fish. Rainbow trout (Oncorhynchus mykiss) were acclimated to cold (11°C; control) and warm (20°C) temperature for 3 weeks followed by exposure to environmentally realistic levels of Cu and hypoxia for 24h. Subsequently, mitochondrial electron transport system (ETS) respiratory activity supported by complexes I-IV (CI-IV), plasma metabolites and condition indices were measured. Warm acclimation reduced fish condition, induced aerobic metabolism and altered the responses of fish to acute temperature shift, hypoxia and Cu. Whereas warm acclimation decelerated the ETS and increased the sensitivity of maximal oxidation rates of the proximal (CI and II) complexes to acute temperature shift, it reduced the thermal sensitivity of state 4 (proton leak). Effects of Cu with and without hypoxia were variable depending on the acclimation status and functional index. Notably, Cu stimulated respiratory activity in the proximal ETS segments, while hypoxia was mostly inhibitory and minimized the stimulatory effect of Cu. The effects of Cu and hypoxia were modified by temperature and showed reciprocal antagonistic interaction on the ETS and plasma metabolites, with modest additive actions limited to CII and IV state 4. Overall, our results indicate that warm acclimation came at a cost of reduced ETS efficiency and increased sensitivity to added stressors. PMID:26513222

  2. Near-surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    NASA Astrophysics Data System (ADS)

    Pérez Díaz, C. L.; Lakhankar, T.; Romanov, P.; Muñoz, J.; Khanbilvardi, R.; Yu, Y.

    2015-08-01

    Land Surface Temperature (LST) is a key variable (commonly studied to understand the hydrological cycle) that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air) and snow skin temperature (T-skin) helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS) LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE) for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

  3. Temperature Deviations in the Midlatitude Mesosphere During Stratospheric Warmings as Measured with Rayleigh-Scatter Lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent; Fish, Chad; Herron, Joshua P.

    2016-06-01

    While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected an extensive set of temperature data for 11 years in the 45-90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the midlatitude mesospheric temperatures during these SSW events. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions during SSW events, and warmings in the lower mesosphere.

  4. Temperature inverted haloclines provide winter warm-water refugia for manatees in southwest Florida

    USGS Publications Warehouse

    Stith, Bradley M.; Reid, James P.; Langtimm, Catherine A.; Swain, Eric D.; Doyle, Terry J.; Slone, Daniel H.; Decker, Jeremy D.; Soderqvist, Lars E.

    2010-01-01

    Florida manatees (Trichechus manatus latirostris) overwintering in the Ten Thousand Islands and western Everglades have no access to power plants or major artesian springs that provide warm-water refugia in other parts of Florida. Instead, hundreds of manatees aggregate at artificial canals, basins, and natural deep water sites that act as passive thermal refugia (PTR). Monitoring at two canal sites revealed temperature inverted haloclines, which provided warm salty bottom layers that generally remained above temperatures considered adverse for manatees. At the largest PTR, the warmer bottom layer disappeared unless significant salt stratification was maintained by upstream freshwater inflow over a persistent tidal wedge. A detailed three-dimensional hydrology model showed that salinity stratification inhibited vertical convection induced by atmospheric cooling. Management or creation of temperature inverted haloclines may be a feasible and desirable option for resource managers to provide passive thermal refugia for manatees and other temperature sensitive aquatic species.

  5. Determination of Warm Working Temperature Range for In Situ Alm-TiB2p Composite

    NASA Astrophysics Data System (ADS)

    Mishra, R.; Alexander, A.; Srinivasan, K.

    2015-04-01

    Composites with hard undeformable particles are better suited for creep resistant applications. Alm-TiB2 particulate composite is one such composite. Its flow properties and formability are investigated and presented in the paper. A suitable temperature range for working this particulate composite is ascertained by using uniaxial axysymmetric compression tests and ring compression tests. Warm working is found to be suitable for this composite in the temperature window of 473-523 K.

  6. Observed changes in seasonal heat waves and warm temperature extremes in the Romanian Carpathians

    NASA Astrophysics Data System (ADS)

    Micu, Dana; Birsan, Marius-Victor; Dumitrescu, Alexandru; Cheval, Sorin

    2015-04-01

    Extreme high temperature have a large impact on environment and human activities, especially in high elevation areas particularly sensitive to the recent climate warming. The climate of the Romanian Carpathians became warmer particularly in winter, spring and summer, exibiting a significant increasing frequency of warm extremes. The paper investigates the seasonal changes in the frequency, duration and intensity of heat waves in relation to the shifts in the daily distribution of maximum temperatures over a 50-year period of meteorological observations (1961-2010). The paper uses the heat wave definition recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) and exploits the gridded daily dataset of maximum temperature at 0.1° resolution (~10 km) developed in the framework of the CarpatClim project (www.carpatclim.eu). The seasonal changes in heat waves behavior were identified using the Mann-Kendall non-parametric trend test. The results suggest an increase in heat wave frequency and a lengthening of intervals affected by warm temperature extremes all over the study region, which are explained by the shifts in the upper (extreme) tail of the daily maximum temperature distribution in most seasons. The trends are consistent across the region and are well correlated to the positive phases of the East Atlantic Oscillation. Our results are in good agreement with the previous temperature-related studies concerning the Carpathian region. This study was realized within the framework of the project GENCLIM, financed by UEFISCDI, code PN-II 151/2014.

  7. Regional temperature and precipitation changes under high-end (≥4°C) global warming.

    PubMed

    Sanderson, M G; Hemming, D L; Betts, R A

    2011-01-13

    Climate models vary widely in their projections of both global mean temperature rise and regional climate changes, but are there any systematic differences in regional changes associated with different levels of global climate sensitivity? This paper examines model projections of climate change over the twenty-first century from the Intergovernmental Panel on Climate Change Fourth Assessment Report which used the A2 scenario from the IPCC Special Report on Emissions Scenarios, assessing whether different regional responses can be seen in models categorized as 'high-end' (those projecting 4°C or more by the end of the twenty-first century relative to the preindustrial). It also identifies regions where the largest climate changes are projected under high-end warming. The mean spatial patterns of change, normalized against the global rate of warming, are generally similar in high-end and 'non-high-end' simulations. The exception is the higher latitudes, where land areas warm relatively faster in boreal summer in high-end models, but sea ice areas show varying differences in boreal winter. Many continental interiors warm approximately twice as fast as the global average, with this being particularly accentuated in boreal summer, and the winter-time Arctic Ocean temperatures rise more than three times faster than the global average. Large temperature increases and precipitation decreases are projected in some of the regions that currently experience water resource pressures, including Mediterranean fringe regions, indicating enhanced pressure on water resources in these areas. PMID:21115514

  8. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  9. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  10. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  11. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  12. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  13. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  14. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  15. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  16. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  17. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  18. Air pollution control and decreasing new particle formation lead to strong climate warming

    NASA Astrophysics Data System (ADS)

    Makkonen, R.; Asmi, A.; Kerminen, V.-M.; Boy, M.; Arneth, A.; Hari, P.; Kulmala, M.

    2011-09-01

    The number of cloud droplets determines several climatically relevant cloud properties. A major cause for the high uncertainty in the indirect aerosol forcing is the availability of cloud condensation nuclei (CCN), which in turn is highly sensitive to atmospheric new particle formation. Here we present the effect of new particle formation on anthropogenic aerosol forcing in present-day (year 2000) and future (year 2100) conditions. The total aerosol forcing (-1.61 W m-2 in year 2000) is simulated to be greatly reduced in the future, to -0.23 W m-2, mainly due to decrease in SO2 emissions and resulting decrease in new particle formation. With the total aerosol forcing decreasing in response to air pollution control measures taking effect, warming from increased greenhouse gas concentrations can potentially increase at a very rapid rate.

  19. The influence of clean air entrainment on the droplet effective radius of warm maritime convective clouds

    SciTech Connect

    Pontikis, C.A.; Hicks, E.M.

    1993-09-01

    The influence of clear air entrainment on the droplet effective radius of cloudy air parcels is investigated theoretically and experimentally by using data collected in 16 warm maritime tropical cumuli during the Joint Hawaii Warm Rain Project (1985). The theoretical study consists of calculations of the droplet spectrum, droplet effective radius, and liquid water content performed by an entraining cloud parcel model for different entrainment-mixing scenarios. The numerical simulation results are interpreted by means of an analytic equation of the droplet effective radius expressed as a function of both the liquid water content and the droplet concentration. In the experiment study, the behavior of the effective radius is examined at all scales as a function of the liquid water content, used as a dilution degree indicator. At a given cloud level, in the abscence of secondary droplet activation, the effective radius of the droplet spectrum of small-scale parcels (10-Hz data) is roughly independent of the liquid water content and appears unaffected by entrainment. In contrast, if secondary droplet activation occurs in diluted ascending cloud parcels, a wide range of effective radius values is observed for a given liquid water content as a result of the induced variation of the droplet concentration. Further, mean cloud pass effective radii increase with increasing mean pass liquid water contents and mean pass height above cloud base. The results limit the validity of the classical cloud effective radius parameterizations used in the radiative transfer calculations in climate models and some suggestions to improve these parameterizations are presented.

  20. Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter

    PubMed Central

    Bang, W.; Albright, B. J.; Bradley, P. A.; Vold, E. L.; Boettger, J. C.; Fernández, J. C.

    2016-01-01

    Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1–100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly with temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. These simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement. PMID:27405664

  1. Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter

    NASA Astrophysics Data System (ADS)

    Bang, W.; Albright, B. J.; Bradley, P. A.; Vold, E. L.; Boettger, J. C.; Fernández, J. C.

    2016-07-01

    Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1–100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly with temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. These simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement.

  2. Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter

    DOE PAGESBeta

    Bang, Woosuk; Albright, Brian James; Bradley, Paul Andrew; Vold, Erik Lehman; Boettger, Jonathan Carl; Fernández, Juan Carlos

    2016-07-12

    Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1–100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly withmore » temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. In conclusion, these simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement.« less

  3. Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter.

    PubMed

    Bang, W; Albright, B J; Bradley, P A; Vold, E L; Boettger, J C; Fernández, J C

    2016-01-01

    Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1-100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly with temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. These simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement. PMID:27405664

  4. Changes in the dynamics of foliar N metabolites in oak saplings by drought and air warming depend on species and soil type.

    PubMed

    Hu, Bin; Simon, Judy; Günthardt-Goerg, Madeleine S; Arend, Matthias; Kuster, Thomas M; Rennenberg, Heinz

    2015-01-01

    Climate change poses direct or indirect influences on physiological mechanisms in plants. In particular, long living plants like trees have to cope with the predicted climate changes (i.e. drought and air warming) during their life span. The present study aimed to quantify the consequences of simulated climate change for foliar N metabolites over a drought-rewetting-drought course. Saplings of three Central European oak species (i.e. Quercus robur, Q. petraea, Q. pubescens) were tested on two different soil types (i.e. acidic and calcareous). Consecutive drought periods increased foliar amino acid-N and soluble protein-N concentrations at the expense of structural N in all three oak species. In addition, transient effects on foliar metabolite dynamics were observed over the drought-rewetting-drought course. The lowest levels of foliar soluble protein-N, amino acid-N and potassium cation with a minor response to drought and air warming were found in the oak species originating from the driest/warmest habitat (Q. pubescens) compared to Q. robur and Q. petraea. Higher foliar osmolyte-N and potassium under drought and air warming were observed in all oak species when grown on calcareous versus acidic soil. These results indicate that species-specific differences in physiological mechanisms to compensate drought and elevated temperature are modified by soil acidity. PMID:25961713

  5. Changes in the Dynamics of Foliar N Metabolites in Oak Saplings by Drought and Air Warming Depend on Species and Soil Type

    PubMed Central

    Hu, Bin; Simon, Judy; Günthardt-Goerg, Madeleine S.; Arend, Matthias; Kuster, Thomas M.; Rennenberg, Heinz

    2015-01-01

    Climate change poses direct or indirect influences on physiological mechanisms in plants. In particular, long living plants like trees have to cope with the predicted climate changes (i.e. drought and air warming) during their life span. The present study aimed to quantify the consequences of simulated climate change for foliar N metabolites over a drought-rewetting-drought course. Saplings of three Central European oak species (i.e. Quercus robur, Q. petraea, Q. pubescens) were tested on two different soil types (i.e. acidic and calcareous). Consecutive drought periods increased foliar amino acid-N and soluble protein-N concentrations at the expense of structural N in all three oak species. In addition, transient effects on foliar metabolite dynamics were observed over the drought-rewetting-drought course. The lowest levels of foliar soluble protein-N, amino acid-N and potassium cation with a minor response to drought and air warming were found in the oak species originating from the driest/warmest habitat (Q. pubescens) compared to Q. robur and Q. petraea. Higher foliar osmolyte-N and potassium under drought and air warming were observed in all oak species when grown on calcareous versus acidic soil. These results indicate that species-specific differences in physiological mechanisms to compensate drought and elevated temperature are modified by soil acidity. PMID:25961713

  6. Comparison of MODIS Satellite Land Surface Temperature with Air Temperature along a 5000-metre Elevation Transect on Kilimanjaro, Tanzania.

    NASA Astrophysics Data System (ADS)

    Pepin, N. C.; Williams, R.; Maeda, E. E.

    2015-12-01

    There is concern that high elevations may be warming more rapidly than lower elevations, but there is a lack of observational data from weather stations in the high mountains. One alternative data source is satellite LST (Land Surface Temperature) which has extensive spatial coverage. This study compares instantaneous values of LST (1030 and 2230 local solar time) as measured by the MODIS MOD11A2 product at 1 km resolution with equivalent screen level air temperatures (in the same pixel) measured from a transect of 22 in situ weather stations across Kilimanjaro ranging in elevation from 990 to 5803 m. Data consists of 11 years on the SW slope and 3 years on the NE slope, equating to >500 and ~140 octtads (8-day periods) respectively. Results show substantial differences between LST and local air temperature, sometimes up to 20C. During the day the LST tends to be higher than air temperature and the reverse is true at night. The differences show large variance, particularly during the daytime, and tend to increase with elevation, particularly on the NE slope of the mountain which faces the sun when the daytime observations are taken (1030 LST). Differences between LST and air temperature are larger in the dry seasons (JF and JJAS), and reduce when conditions are more cloudy. Systematic relationships with cloud cover and vegetation characteristics (as measured by NDVI and MAIAC for the same pixel) are displayed. More vegetation reduces daytime surface heating above the air temperature, but this relationship weakens with elevation. Nighttime differences are more stable and show no relationship with vegetation indices. Therefore the predictability of the LST/air temperature differences reduces at high elevations and it is therefore much more challenging to use satellite data at high elevations to complement in situ air temperature measurements for climate change assessments, especially for daytime maximum temperatures.

  7. Urediospores of Puccinia spp. and other rusts are warm-temperature ice nucleators and harbor ice nucleation active bacteria

    NASA Astrophysics Data System (ADS)

    Morris, C. E.; Sands, D. C.; Glaux, C.; Samsatly, J.; Asaad, S.; Moukahel, A. R.; Gonçalves, F. L. T.; Bigg, E. K.

    2012-10-01

    In light of various features of the biology of the rust fungi and of the epidemiology of the plant diseases they cause that illustrate the important role of rainfall in their life history, we have characterized the ice nucleation activity (INA) of the aerially disseminated spores (urediospores) of this group of fungi. Urediospores of this obligate plant parasite were collected from natural infections from 7 species of weeds in France, from coffee in Brazil and from field and greenhouse-grown wheat in France, the USA, Turkey and Syria. Immersion freezing was used to determine freezing onset temperatures and the abundance of ice nuclei in suspensions of washed spores. Microbiological analyses of spores and subsequent tests of the ice nucleation activity of the bacteria associated with spores were deployed to quantify the contribution of bacteria to the ice nucleation activity of the spores. All samples of spores were ice nucleation active having freezing onset temperatures as warm as -4 °C. Spores in most of the samples carried cells of ice nucleation-active strains of the bacterium Pseudomonas syringae (at rates of less than 1 bacterial cell per 100 urediospores), but bacterial INA accounted for only a small fraction of the INA observed in spore suspensions. Changes in the INA of spore suspensions after treatment with lysozyme suggest that the INA of urediospores involves a polysaccharide. Based on data from the literature, we have estimated the concentrations of urediospores in air at cloud height and in rainfall. These quantities are very similar to those reported for other biological ice nucleators in these same substrates. We suggest that air sampling techniques have ignored the spatial and temporal variability of atmospheric concentrations that occur under conditions propitious for precipitation that could increase their local abundance intermittently. Nevertheless, we propose that the relative low abundance of warm-temperature biological ice nucleators in the

  8. Combined land/sea surface-air-temperature trends, 1949-1972

    SciTech Connect

    Chen, R.S.

    1982-04-01

    A major deficiency in most previous studies of fluctuations in the earth's climate based on air temperature records has been the dearth of data from oceanic areas and the Southern Hemisphere. This study analyzes a unique collection of ship-based observations of surface air temperature assembled by the UK Meteorological Office in parallel with the station-based dataset developed by the National Center for Atmospheric Research from the publications World Weather Records and Monthly Climatic Data for the World. Based on this much more geographically comprehensive database, it is concluded that, during the 24-year period 1949 to 1972, no statistically significant warming or cooling trends were evident in the time series of globally averaged surface air temperature measurements. However, temperature trends did vary latitudinally, with significant cooling in northern extra-tropical latitudes, no trend in equatorial latitudes, and significant but not homogeneous warming in southern extra-tropical latitudes. Time series of air temperatures over land and sea exhibited qualitatively similar behavior over the period 1949 to 1972, indicative of both the comparable quality of the two datasets and the probable lack of significant widespread bias in the land-based measurements due to urban development. The results of this study underscore the need for dense and geographically comprehensive measurements from both land and ocean areas and from both hemispheres in analyzing the global behavior of the earth's climate.

  9. Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Migała, Krzysztof; Urban, Grzegorz; Tomczyński, Karol

    2016-07-01

    The results of meteorological measurements carried out continuously on Mt Śnieżka in Karkonosze mountains since 1880 well document the warming observed on a global scale. Data analysis indicates warming expressed by an increase in the mean annual air temperature of 0.8 °C/100 years. A much higher temperature increase was recorded in the last two decades at the turn of the twenty-first century. Mean decade air temperatures increased from -0.1 to 1.5 °C. It has been shown that there are relationships between air temperature at Mt Śnieżka and global mechanisms of atmospheric and oceanic circulation. Thermal conditions of the Karkonosze (Mt Śnieżka) accurately reflect global climate trends and impact of the North Atlantic Oscillation (NAO) index, macrotypes of atmospheric circulation in Europe (GWL) and Atlantic Multidecadal Oscillation (AMO). The increase in air temperature during the 1989-2012 solar magnetic cycle may reveal a synergy effect to which astrophysical effects and atmospheric and oceanic circulation effects contribute, modified by constantly increasing anthropogenic factors.

  10. Rice grain yield and quality responses to free-air CO2 enrichment combined with soil and water warming.

    PubMed

    Usui, Yasuhiro; Sakai, Hidemitsu; Tokida, Takeshi; Nakamura, Hirofumi; Nakagawa, Hiroshi; Hasegawa, Toshihiro

    2016-03-01

    Rising air temperatures are projected to reduce rice yield and quality, whereas increasing atmospheric CO2 concentrations ([CO2 ]) can increase grain yield. For irrigated rice, ponded water is an important temperature environment, but few open-field evaluations are available on the combined effects of temperature and [CO2 ], which limits our ability to predict future rice production. We conducted free-air CO2 enrichment and soil and water warming experiments, for three growing seasons to determine the yield and quality response to elevated [CO2 ] (+200 μmol mol(-1) , E-[CO2 ]) and soil and water temperatures (+2 °C, E-T). E-[CO2 ] significantly increased biomass and grain yield by approximately 14% averaged over 3 years, mainly because of increased panicle and spikelet density. E-T significantly increased biomass but had no significant effect on the grain yield. E-T decreased days from transplanting to heading by approximately 1%, but days to the maximum tiller number (MTN) stage were reduced by approximately 8%, which limited the panicle density and therefore sink capacity. On the other hand, E-[CO2 ] increased days to the MTN stage by approximately 4%, leading to a greater number of tillers. Grain appearance quality was decreased by both treatments, but E-[CO2 ] showed a much larger effect than did E-T. The significant decrease in undamaged grains (UDG) by E-[CO2 ] was mainly the result of an increased percentage of white-base grains (WBSG), which were negatively correlated with grain protein content. A significant decrease in grain protein content by E-[CO2 ] accounted in part for the increased WBSG. The dependence of WBSG on grain protein content, however, was different among years; the slope and intercept of the relationship were positively correlated with a heat dose above 26 °C. Year-to-year variation in the response of grain appearance quality demonstrated that E-[CO2 ] and rising air temperatures synergistically reduce grain appearance quality of

  11. Effect of Contraction on Turbulence and Temperature Fluctuations Generated by a Warm Grid

    NASA Technical Reports Server (NTRS)

    Mills, Robert R., Jr.; Corrsin, Stanley

    1959-01-01

    Hot-wire anemometer measurements were made of several statistical properties of approximately homogeneous and isotropic fields of turbulence and temperature fluctuations generated by a warm grid in a uniform airstream sent through a 4-to-1 contraction. These measurements were made both in the contraction and in the axisymmetric domain farther downstream. In addition to confirming the well-known turbulence anisotropy induced by strain, the data show effects on the skewnesses of both longitudinal velocity fluctuation (which has zero skewness in isotropic turbulence) and its derivative. The concomitant anisotropy in the temperature field accelerates the decay of temperature fluctuations.

  12. Feasibility study of measuring the temperature and pressure of warm dense matter.

    SciTech Connect

    Rambo, Patrick K.; Schwarz, Jens

    2008-09-01

    We have investigated the feasibility of making accurate measurements of the temperature and pressure of solid-density samples rapidly heated by the Z-Petawatt laser to warm dense matter (WDM) conditions, with temperatures approaching 100eV. The study focused specifically on the heating caused by laser generated proton beams. Based on an extensive literature search and numerical investigations, a WDM experiment is proposed which will accurately measure temperature and pressure based on optical emission from the surface and sample expansion velocity.

  13. Benefits of Leapfrogging to Superefficiency and Low Global Warming Potential Refrigerants in Room Air Conditioning

    SciTech Connect

    Shah, Nihar K.; Wei, Max; Letschert, Virginie; Phadke, Amol A.

    2015-10-01

    Hydrofluorocarbons (HFCs) emitted from uses such as refrigerants and thermal insulating foam, are now the fastest growing greenhouse gases (GHGs), with global warming potentials (GWP) thousands of times higher than carbon dioxide (CO2). Because of the short lifetime of these molecules in the atmosphere,1 mitigating the amount of these short-lived climate pollutants (SLCPs) provides a faster path to climate change mitigation than control of CO2 alone. This has led to proposals from Africa, Europe, India, Island States, and North America to amend the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) to phase-down high-GWP HFCs. Simultaneously, energy efficiency market transformation programs such as standards, labeling and incentive programs are endeavoring to improve the energy efficiency for refrigeration and air conditioning equipment to provide life cycle cost, energy, GHG, and peak load savings. In this paper we provide an estimate of the magnitude of such GHG and peak electric load savings potential, for room air conditioning, if the refrigerant transition and energy efficiency improvement policies are implemented either separately or in parallel.

  14. Drought and air warming affect the species-specific levels of stress-related foliar metabolites of three oak species on acidic and calcareous soil.

    PubMed

    Hu, Bin; Simon, Judy; Rennenberg, Heinz

    2013-05-01

    Climate change as projected for Central Europe will lead to prolonged periods of summer drought and enhanced air temperature. Thus, forest management practices are required to take into account how species performance is adapted to cope with these climate changes. Oak trees may play a major role in future forests because of their relative drought-tolerance compared with other species like beech. Therefore, this study investigated the stress responses (i.e., anti-oxidants, free amino acids) in the leaves of three widely distributed oak species in Central Europe (i.e., Quercus robur L., Q. petraea [Matt.] Libel., Q. pubescens Willd.) to drought, air warming and the combination of drought plus air warming under controlled conditions after periods of spring drought, a short rewetting and summer drought. We quantified foliar levels of thiols, ascorbate, and free amino compounds in Q robur, Q. petraea and Q. pubescens. Our study showed that oak saplings had increased levels of γ-glutamylcysteine and total glutathione and proline with drought and air warming. Foliar ascorbate, glutathione disulfide and dehydroascorbic acid levels were not affected. The comparison of stress responses to drought and/or air warming between the three species showed higher foliar thiol levels in Q. robur and Q. pubescens compared with Q. petraea. For total and reduced ascorbic acid and γ-aminobutyric acid, the highest levels were found in Q. robur. In conclusion, our study showed that foliar anti-oxidant and free amino acid levels were significantly affected by drought plus air warming; however, this effect was species-dependent with the drought-tolerant species of Q. pubescens having the highest reactive oxygen species scavenging capacity among three tested oak species. Furthermore, stress responses as shown by increased levels of foliar anti-oxidants and free amino acids differ between calcareous and acidic soil indicating that the capacities of anti-oxidative defense and osmotic stress

  15. West African warming: Investigating Temperature Trends and their relation between Precipitation Trends over West African Sahel.

    NASA Astrophysics Data System (ADS)

    LY, M., Jr.

    2014-12-01

    It is now admitted that the West African region faces a lot of constraints due to the comprehensiveness of the high climate variability and potential climate change. This is mainly due to the lack of a large number of datasets and long-term records as summarized in the in the IPCC reports. This paper aims to provide improved knowledge and evidence on current and future climate conditions, for better manage climate variability over seasons and from year to year and strengthen the capacity to adapt to future climate change. In this regards, we analyse the evolution of some extreme temperature and precipitation indices over a large area of West Africa. Prior results show a general warming trend at individual stations throughout the region during the period from 1960 to 2010, namely negative trends in the number of cool nights, and positive trends in the number of warm days and length of warm spells. Trends in rainfall-related indices are not as uniform as the ones in temperatures, rather they display marked multi-decadal variability, as expected. To refine analyses of temperature variations and their relation to precipitation we investigated on cluster analysis aimed at distinguishing different sub-regions, such as continental and coastal, and relevant seasons, such as wet, dry/cold and dry warm. This will contribute to significantly lower uncertainties by developing better and more tailored temperature and precipitation trends to inform the user communities on climate related risks, as well as enhance their resilience to food insecurity and other climate related disasters.

  16. Forced-air warming: a source of airborne contamination in the operating room?

    PubMed Central

    Albrecht, Mark; Gauthier, Robert; Leaper, David

    2009-01-01

    Forced-air-warming (FAW) is an effective and widely used means for maintaining surgical normothermia, but FAW also has the potential to generate and mobilize airborne contamination in the operating room. We measured the emission of viable and non-viable forms of airborne contamination from an arbitrary selection of FAW blowers (n=25) in the operating room. A laser particle counter measured particulate concentrations of the air near the intake filter and in the distal hose airstream. Filtration efficiency was calculated as the reduction in particulate concentration in the distal hose airstream relative to that of the intake. Microbial colonization of the FAW blower's internal hose surfaces was assessed by culturing the microorganisms recovered through swabbing (n=17) and rinsing (n=9) techniques. Particle counting revealed that 24% of FAW blowers were emitting significant levels of internally generated airborne contamination in the 0.5 to 5.0 µm size range, evidenced by a steep decrease in FAW blower filtration efficiency for particles 0.5 to 5.0 µm in size. The particle size-range-specific reduction in efficiency could not be explained by the filtration properties of the intake filter. Instead, the reduction was found to be caused by size-range-specific particle generation within the FAW blowers. Microorganisms were detected on the internal air path surfaces of 94% of FAW blowers. The design of FAW blowers was found to be questionable for preventing the build-up of internal contamination and the emission of airborne contamination into the operating room. Although we did not evaluate the link between FAW and surgical site infection rates, a significant percentage of FAW blowers with positive microbial cultures were emitting internally generated airborne contamination within the size range of free floating bacteria and fungi (<4 µm) that could, conceivably, settle onto the surgical site. PMID:21808690

  17. Air temperature variation across the seed cotton dryer mixpoint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eighteen tests were conducted in six gins in the fall of 2008 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the...

  18. Possible Economies in Air-Conditioning by Accepting Temperature Swings.

    ERIC Educational Resources Information Center

    Loudon, A. G.; Petherbridge, P.

    Public building air conditioning systems, which use constant and varying heat and cooling loads, are compared and investigated. Experiments indicated that constant temperature controls based on outside air temperature alone were inefficient. Ventilating a building with outside air and the methods of doing so are cited as being the most economical…

  19. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  20. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  1. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  2. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  3. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  4. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  5. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  6. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  7. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  8. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  9. AIR TEMPERATURE DISTRIBUTION IN SEED COTTON DRYING SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ten tests were conducted in the fall of 2007 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the airflow ductwork...

  10. Acoustic method for measuring air temperature and humidity in rooms

    NASA Astrophysics Data System (ADS)

    Kanev, N. G.

    2014-05-01

    A method is proposed to determine air temperature and humidity in rooms with a system of sound sources and receivers, making it possible to find the sound velocity and reverberation time. Nomograms for determining the air temperature and relative air humidity are constructed from the found sound velocity and time reverberation values. The required accuracy of measuring these parameters is estimated.

  11. Temperature-mediated biotic interactions influence enemy release of nonnative species in warming environments.

    PubMed

    Fey, Samuel B; Herren, Cristina M

    2014-08-01

    "Enemy release" occurs when invading species suffer from interactions with pathogens, parasites, herbivores, or predators to a lesser degree than native species due to a lack of shared evolutionary history. Here we provide strong support for the hypothesis that variable thermal sensitivities between a consumer and its resources can generate temperature-dependent enemy release using both a mathematical model and a field experiment. We identify three common scenarios where changes in temperature should alter enemy release based on asymmetric responses among enemies and their resources to changes in temperature: (1) the vital rates of a shared enemy are more sensitive to changes in temperature than its resources, (2) the enemy's thermal maximum for consumption is higher than the resources' maxima for growth, and (3) the invading resource has a higher thermal maximum for growth than its native competitor. Mathematical representations indicated that warming is capable of altering enemy release in each of these three scenarios. We also tested our hypothesis using a mesocosm warming experiment in a system that exhibits variable thermal sensitivities between a predator and its native and nonnative prey. We conducted a six-week experiment manipulating the presence of Lepomis sunfish (present, absent) and water temperature (ambient, heated) using the nonnative crustacean zooplankter, Daphnia lumholtzi, whose morphological defenses reduce predation from juvenile sunfish relative to native Daphnia pulex. Our results indicate that D. lumholtzi benefited to a greater extent from the presence of Lepomis predators as temperatures increase. Taken together, our model and experiment indicate that changes in environmental temperature may directly influence the success of nonnative species and may assist with forecasting the community consequences of biological invasions in a warming world. PMID:25230475

  12. Ambient temperature, air pollution, and heart rate variability in an aging population.

    PubMed

    Ren, Cizao; O'Neill, Marie S; Park, Sung Kyun; Sparrow, David; Vokonas, Pantel; Schwartz, Joel

    2011-05-01

    Studies show that ambient temperature and air pollution are associated with cardiovascular disease and that they may interact to affect cardiovascular events. However, few epidemiologic studies have examined mechanisms through which ambient temperature may influence cardiovascular function. The authors examined whether temperature was associated with heart rate variability (HRV) in a Boston, Massachusetts, study population and whether such associations were modified by ambient air pollution concentrations. The population was a cohort of 694 older men examined between 2000 and 2008. The authors fitted a mixed model to examine associations between temperature and air pollution and their interactions with repeated HRV measurements, adjusting for covariates selected a priori on the basis of their previous studies. Results showed that higher ambient temperature was associated with decreases in HRV measures (standard deviation of normal-to-normal intervals, low-frequency power, and high-frequency power) during the warm season but not during the cold season. These warm-season associations were significantly greater when ambient ozone levels were higher (>22.3 ppb) but did not differ according to levels of ambient fine (≤2.5 μm) particulate matter. The authors conclude that temperature and ozone, exposures to both of which are expected to increase with climate change, might act together to worsen cardiovascular health and/or precipitate cardiovascular events via autonomic nervous system dysfunction. PMID:21385834

  13. Warming Amplification of Minimum and Maximum Temperatures over High-Elevation Regions across the Globe

    PubMed Central

    Wang, Mengben; Jiménez, Claudia Villarroel

    2015-01-01

    An analysis of the annual mean temperature (TMEAN) (1961–2010) has revealed that warming amplification (altitudinal amplification and regional amplification) is a common feature of major high-elevation regions across the globe against the background of global warming since the mid-20th century. In this study, the authors further examine whether this holds for annual mean minimum temperature (TMIN) and annual mean maximum temperature (TMAX) (1961–2010) on a global scale. The extraction method of warming component of altitude, and the paired region comparison method were used in this study. Results show that a significant altitudinal amplification trend in TMIN (TMAX) is detected in all (four) of the six high-elevation regions tested, and the average magnitude of altitudinal amplification trend for TMIN (TMAX) [0.306±0.086 °C km-1(0.154±0.213 °C km-1)] is substantially larger (smaller) than TMEAN (0.230±0.073 °C km-1) during the period 1961–2010. For the five paired high- and low-elevation regions available, regional amplification is detected in the four high-elevation regions for TMIN and TMAX (respectively or as a whole). Qualitatively, highly (largely) consistent results are observed for TMIN (TMAX) compared with those for TMEAN. PMID:26461461

  14. Brain Temperature in Spontaneously Hypertensive Rats during Physical Exercise in Temperate and Warm Environments

    PubMed Central

    Drummond, Lucas Rios; Kunstetter, Ana Cançado; Vaz, Filipe Ferreira; Campos, Helton Oliveira; de Andrade, André Gustavo Pereira; Coimbra, Cândido Celso; Natali, Antônio José

    2016-01-01

    This study aimed to evaluate brain temperature (Tbrain) changes in spontaneously hypertensive rats (SHRs) subjected to two different physical exercise protocols in temperate or warm environments. We also investigated whether hypertension affects the kinetics of exercise-induced increases in Tbrain relative to the kinetics of abdominal temperature (Tabd) increases. Male 16-week-old normotensive Wistar rats (NWRs) and SHRs were implanted with an abdominal temperature sensor and a guide cannula in the frontal cortex to enable the insertion of a thermistor to measure Tbrain. Next, the animals were subjected to incremental-speed (initial speed of 10 m/min; speed was increased by 1 m/min every 3 min) or constant-speed (60% of the maximum speed) treadmill running until they were fatigued in a temperate (25°C) or warm (32°C) environment. Tbrain, Tabd and tail skin temperature were measured every min throughout the exercise trials. During incremental and constant exercise at 25°C and 32°C, the SHR group exhibited greater increases in Tbrain and Tabd relative to the NWR group. Irrespective of the environment, the heat loss threshold was attained at higher temperatures (either Tbrain or Tabd) in the SHRs. Moreover, the brain-abdominal temperature differential was lower at 32°C in the SHRs than in the NWRs during treadmill running. Overall, we conclude that SHRs exhibit enhanced brain hyperthermia during exercise and that hypertension influences the kinetics of the Tbrain relative to the Tabd increases, particularly during exercise in a warm environment. PMID:27214497

  15. Brain Temperature in Spontaneously Hypertensive Rats during Physical Exercise in Temperate and Warm Environments.

    PubMed

    Drummond, Lucas Rios; Kunstetter, Ana Cançado; Vaz, Filipe Ferreira; Campos, Helton Oliveira; Andrade, André Gustavo Pereira de; Coimbra, Cândido Celso; Natali, Antônio José; Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau

    2016-01-01

    This study aimed to evaluate brain temperature (Tbrain) changes in spontaneously hypertensive rats (SHRs) subjected to two different physical exercise protocols in temperate or warm environments. We also investigated whether hypertension affects the kinetics of exercise-induced increases in Tbrain relative to the kinetics of abdominal temperature (Tabd) increases. Male 16-week-old normotensive Wistar rats (NWRs) and SHRs were implanted with an abdominal temperature sensor and a guide cannula in the frontal cortex to enable the insertion of a thermistor to measure Tbrain. Next, the animals were subjected to incremental-speed (initial speed of 10 m/min; speed was increased by 1 m/min every 3 min) or constant-speed (60% of the maximum speed) treadmill running until they were fatigued in a temperate (25°C) or warm (32°C) environment. Tbrain, Tabd and tail skin temperature were measured every min throughout the exercise trials. During incremental and constant exercise at 25°C and 32°C, the SHR group exhibited greater increases in Tbrain and Tabd relative to the NWR group. Irrespective of the environment, the heat loss threshold was attained at higher temperatures (either Tbrain or Tabd) in the SHRs. Moreover, the brain-abdominal temperature differential was lower at 32°C in the SHRs than in the NWRs during treadmill running. Overall, we conclude that SHRs exhibit enhanced brain hyperthermia during exercise and that hypertension influences the kinetics of the Tbrain relative to the Tabd increases, particularly during exercise in a warm environment. PMID:27214497

  16. Comparison of Vertical Soundings and Sidewall Air Temperature Measurements in a Small Alpine Basin

    SciTech Connect

    Whiteman, Charles D.; Eisenbach, Stefan; Pospichal, Bernhard; Steinacker, Reinhold

    2004-11-01

    Tethered balloon soundings from two sites on the floor of a 1-km diameter limestone sinkhole in the Eastern Alps are compared with pseudo-vertical temperature ‘soundings’ from three lines of temperature data loggers on the basin’s northwest, southwest and southeast sidewalls. Under stable nighttime conditions with low background winds, the pseudo-vertical profiles from all three lines were good proxies for free air temperature soundings over the basin center, with a mean nighttime cold temperature bias of about 0.4°C and a standard deviation of 0.4°C. Cold biases were highest in the upper basin where relatively warm air subsides to replace air that spills out of the basin through the lowest altitude saddle. On a windy night, standard deviations increased to 1 - 2°C. After sunrise, the varying exposures of the data loggers to sunlight made the pseudo-vertical profiles less useful as proxies for free air soundings. The good correspondence between sidewall and free air temperatures during high static stability conditions suggests that sidewall soundings will prove useful in monitoring temperatures and vertical temperature gradients in the sinkhole. The sidewall soundings can produce more frequent profiles at less cost than tethersondes or rawinsondes, and provide valuable advantages for some types of meteorological analyses.

  17. Synchronous change of atmospheric CO2 and Antarctic temperature during the last deglacial warming.

    PubMed

    Parrenin, F; Masson-Delmotte, V; Köhler, P; Raynaud, D; Paillard, D; Schwander, J; Barbante, C; Landais, A; Wegner, A; Jouzel, J

    2013-03-01

    Understanding the role of atmospheric CO2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records of atmospheric CO2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies. PMID:23449589

  18. A microbiological evaluation of warm air hand driers with respect to hand hygiene and the washroom environment.

    PubMed

    Taylor, J H; Brown, K L; Toivenen, J; Holah, J T

    2000-12-01

    A finger rinse technique for counting micro-organisms on hands showed no significant difference in the level of recovered micro-organisms following hand drying using either warm air or paper towels. Contact plate results appeared to reflect the degree of dampness of hands after drying rather than the actual numbers of micro-organisms on the hands. In laboratory tests, a reduction in airborne count of Pseudomonas aeruginosa and Staphylococcus aureus of between 40 and 75% was achieved from 600 readings comparing inlets and outlets of warm air hand driers. In washroom trials, the number of airborne micro-organisms was reduced by between 30 and 75%. Air emitted from the outlet of the driers contained significantly fewer micro-organisms than air entering the driers. Drying of hands with hand driers was no more likely to generate airborne micro-organisms than drying with paper towels. Levels of micro-organisms on external surfaces of hand driers were not significantly different to those on other washroom surfaces. This work shows that warm air hand driers, of the type used in this study, are a hygienic method of drying hands and therefore appropriate for use in both the healthcare and food industry. PMID:11123464

  19. Rapid fluctuations of the air and surface temperature in the city of Bucharest (Romania)

    NASA Astrophysics Data System (ADS)

    Cheval, Sorin; Dumitrescu, Alexandru; Hustiu, Mihaita-Cristinel

    2016-04-01

    Urban areas derive significant changes of the ambient temperature generating specific challenges for society and infrastructure. Extreme temperature events, heat and cold waves affect the human comfort, increase the health risk, and require specific building regulations and emergency preparedness, strongly related to the magnitude and frequency of the thermal hazards. Rapid changes of the temperature put a particular stress for the urban settlements, and the topic has been approached constantly in the scientific literature. Due to its geographical position in a plain area with a temperate climate and noticeable continental influence, the city of Bucharest (Romania) deals with high seasonal and daily temperature variations. However, rapid fluctuations also occur at sub-daily scale caused by cold or warm air advections or by very local effects (e.g. radiative heat exchange, local precipitation). For example, in the area of Bucharest, the cold fronts of the warm season may trigger temperature decreasing up to 10-15 centigrades / hour, while warm advections lead to increasing of 1-2 centigrades / hour. This study focuses on the hourly and sub-hourly temperature variations over the period November 2014 - February 2016, using air temperature data collected from urban sensors and meteorological stations of the national network, and land surface temperature data obtained from satellite remote sensing. The analysis returns different statistics, such as magnitude, intensity, frequency, simultaneous occurrence and areal coverage of the rapid temperature fluctuations. Furthermore, the generating factors for each case study are assessed, and the results are used to define some preliminary patterns and enhance the urban temperature forecast at fine scale. The study was funded by the Romanian Programme Partnership in Priority Domains, PN - II - PCCA - 2013 - 4 - 0509 - Reducing UHI effects to improve urban comfort and balance energy consumption in Bucharest (REDBHI).

  20. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  1. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  2. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  3. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  4. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  5. Evaluation of Proposed Solutions to Global Warming, Air Pollution, and Energy Security

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.

    2008-12-01

    This study reviews and ranks major proposed solutions to global warming, air pollution mortality, and energy security while considering other impacts of the proposed solutions, such as on water supply, land use, wildlife, resource availability, thermal pollution, water chemical pollution, nuclear proliferation, and undernutrition. Nine electric power sources and two liquid fuel options are considered. The electricity sources include solar-photovoltaics (PV), concentrated solar power (CSP), wind, geothermal, hydroelectric, wave, tidal, nuclear, and coal with carbon capture and storage (CCS) technology. The liquid fuel options include corn-E85 and cellulosic E85. To place the electric and liquid fuel sources on an equal footing, we examine their comparative abilities to address the problems mentioned by powering new-technology vehicles, including battery-electric vehicles (BEVs), hydrogen fuel cell vehicles (HFCVs), and flex-fuel vehicles run on E85. Twelve combinations of energy source-vehicle type are considered. Upon ranking and weighting each combination with respect to each of 11 impact categories, four clear divisions of ranking, or tiers, emerge. Tier 1 (highest-ranked) includes wind-BEVs and wind-HFCVs. Tier 2 includes CSP-BEVs, geothermal-BEVs, PV-BEVs, tidal-BEVs, and wave-BEVs. Tier 3 includes hydro-BEVs, nuclear-BEVs, and CCS-BEVs. Tier 4 includes corn- and cellulosic-E85. Wind-BEVs ranked first in six out of 11 categories, including the two most important, mortality and climate damage reduction. Although HFCVs are less efficient than BEVs, wind- HFCVs ranked second among all combinations. Tier 2 options provide significant benefits and are recommended. Tier 3 options are less desirable. However, hydroelectricity, which was ranked ahead of coal- CCS and nuclear with respect to climate and health, is an excellent load balancer, thus strongly recommended. The Tier-4 combinations (cellulosic- and corn-E85) were ranked lowest overall and with respect to

  6. Effects of environmental temperature change on mercury absorption in aquatic organisms with respect to climate warming.

    PubMed

    Pack, Eun Chul; Lee, Seung Ha; Kim, Chun Huem; Lim, Chae Hee; Sung, Dea Gwan; Kim, Mee Hye; Park, Ki Hwan; Lim, Kyung Min; Choi, Dal Woong; Kim, Suhng Wook

    2014-01-01

    Because of global warming, the quantity of naturally generated mercury (Hg) will increase, subsequently methylation of Hg existing in seawater may be enhanced, and the content of metal in marine products rise which consequently results in harm to human health. Studies of the effects of temperatures on Hg absorption have not been adequate. In this study, in order to observe the effects of temperature changes on Hg absorption, inorganic Hg or methylmercury (MeHg) was added to water tanks containing loaches. Loach survival rates decreased with rising temperatures, duration, and exposure concentrations in individuals exposed to inorganic Hg and MeHg. The MeHg-treated group died sooner than the inorganic Hg-exposed group. The total Hg and MeHg content significantly increased with temperature and time in both metal-exposed groups. The MeHg-treated group had higher metal absorption rates than inorganic Hg-treated loaches. The correlation coefficients for temperature elevation and absorption were significant in both groups. The results of this study may be used as basic data for assessing in vivo hazards from environmental changes such as climate warming. PMID:25343296

  7. Sources of global warming in upper ocean temperature during El Niño

    USGS Publications Warehouse

    White, Warren B.; Cayan, Daniel R.; Dettinger, Mike; Auad, Guillermo

    2001-01-01

    Global average sea surface temperature (SST) from 40°S to 60°N fluctuates ±0.3°C on interannual period scales, with global warming (cooling) during El Niño (La Niña). About 90% of the global warming during El Niño occurs in the tropical global ocean from 20°S to 20°N, half because of large SST anomalies in the tropical Pacific associated with El Niño and the other half because of warm SST anomalies occurring over ∼80% of the tropical global ocean. From examination of National Centers for Environmental Prediction [Kalnay et al., 1996] and Comprehensive Ocean-Atmosphere Data Set [Woodruff et al., 1993] reanalyses, tropical global warming during El Niño is associated with higher troposphere moisture content and cloud cover, with reduced trade wind intensity occurring during the onset phase of El Niño. During this onset phase the tropical global average diabatic heat storage tendency in the layer above the main pycnocline is 1–3 W m−2above normal. Its principal source is a reduction in the poleward Ekman heat flux out of the tropical ocean of 2–5 W m−2. Subsequently, peak tropical global warming during El Niño is dissipated by an increase in the flux of latent heat to the troposphere of 2–5 W m−2, with reduced shortwave and longwave radiative fluxes in response to increased cloud cover tending to cancel each other. In the extratropical global ocean the reduction in poleward Ekman heat flux out of the tropics during the onset of El Niño tends to be balanced by reduction in the flux of latent heat to the troposphere. Thus global warming and cooling during Earth's internal mode of interannual climate variability arise from fluctuations in the global hydrological balance, not the global radiation balance. Since it occurs in the absence of extraterrestrial and anthropogenic forcing, global warming on decadal, interdecadal, and centennial period scales may also occur in association with Earth's internal modes of climate variability on those scales.

  8. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    NASA Astrophysics Data System (ADS)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-10-01

    Uncertainties in the satellite-derived surface skin temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) 2003-2014 were investigated and the three data sets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. The AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically warmer up to 1.65 K at the sea ice boundary and colder down to -2.04 K in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a less accurate GCM forecast over the seasonally varying frozen oceans than the microwave data. The three data sets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~ 2.8 ± 1.9 K decade-1) in the northern high regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  9. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    NASA Astrophysics Data System (ADS)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-05-01

    Uncertainties in the satellite-derived Surface Skin Temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) of 2003-2014 were investigated and the three datasets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically up to 1.65 K warmer at the sea ice boundary and up to 2.04 K colder in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a~less accurate GCM forecast over the seasonally-varying frozen oceans than the microwave data. The three datasets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~2.8 ± 1.9 K decade-1) in the northern high latitude regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  10. Effects of warm sea-surface temperature anomalies on the blue petrel at the Kerguelen Islands

    PubMed Central

    Guinet, C.; Chastel, O.; Koudil, M.; Durbec, J. P.; Jouventin, P.

    1998-01-01

    Several long-term studies on Southern Ocean seabirds and seals have suggested a possible link between major declines in breeding performance and El Niño Southern Oscillation events. We report that the breeding performances and body condition of the blue petrel (Halobaena carulea) on the Kerguelen Islands is depressed by episodic, warm sea-surface temperatures (SSTs) in the winter before breeding. Lagged cross correlations between SSTs in the Kerguelen sector and the Southern Oscillation Index indicate that warm SSTs were found south of Kerguelen Islands within a year of, and between 4.2 and 5.4 years after, an El Niño event took place. These results can be discussed with respect to the recently described Antarctic Circumpolar Wave that drives climatic anomalies eastward around the Southern Ocean.

  11. Air pollution control and decreasing new particle formation lead to strong climate warming

    NASA Astrophysics Data System (ADS)

    Makkonen, R.; Asmi, A.; Kerminen, V.-M.; Boy, M.; Arneth, A.; Hari, P.; Kulmala, M.

    2012-02-01

    The number concentration of cloud droplets determines several climatically relevant cloud properties. A major cause for the high uncertainty in the indirect aerosol forcing is the availability of cloud condensation nuclei (CCN), which in turn is highly sensitive to atmospheric new particle formation. Here we present the effect of new particle formation on anthropogenic aerosol forcing in present-day (year 2000) and future (year 2100) conditions. The present-day total aerosol forcing is increased from -1.0 W m-2 to -1.6 W m-2 when nucleation is introduced into the model. Nucleation doubles the change in aerosol forcing between years 2000 and 2100, from +0.6 W m-2 to +1.4 W m-2. Two climate feedbacks are studied, resulting in additional negative forcings of -0.1 W m-2 (+10% DMS emissions in year 2100) and -0.5 W m-2 (+50% BVOC emissions in year 2100). With the total aerosol forcing diminishing in response to air pollution control measures taking effect, warming from increased greenhouse gas concentrations can potentially increase at a very rapid rate.

  12. The effect of air temperature and human thermal indices on mortality in Athens, Greece

    NASA Astrophysics Data System (ADS)

    Nastos, Panagiotis T.; Matzarakis, Andreas

    2012-05-01

    This paper investigates whether there is any association between the daily mortality for the wider region of Athens, Greece and the thermal conditions, for the 10-year period 1992-2001. The daily mortality datasets were acquired from the Hellenic Statistical Service and the daily meteorological datasets, concerning daily maximum and minimum air temperature, from the Hellinikon/Athens meteorological station, established at the headquarters of the Greek Meteorological Service. Besides, the daily values of the thermal indices Physiologically Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) were evaluated in order to interpret the grade of physiological stress. The first step was the application of Pearson's χ 2 test to the compiled contingency tables, resulting in that the probability of independence is zero ( p = 0.000); namely, mortality is in close relation to the air temperature and PET/UTCI. Furthermore, the findings extracted by the generalized linear models showed that, statistically significant relationships ( p < 0.01) between air temperature, PET, UTCI and mortality exist on the same day. More concretely, on one hand during the cold period (October-March), a 10°C decrease in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 13%, 15%, 2%, 7% and 6% of the probability having a death, respectively. On the other hand, during the warm period (April-September), a 10°C increase in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 3%, 1%, 10%, 3% and 5% of the probability having a death, respectively. Taking into consideration the time lag effect of the examined parameters on mortality, it was found that significant effects of 3-day lag during the cold period appears against 1-day lag during the warm period. In spite of the general aspect that cold conditions seem to be favourable factors for daily mortality

  13. Reduced diurnal temperature range does not change warming impacts on ecosystem carbon balance of Mediterranean grassland mesocosms

    DOE PAGESBeta

    Phillips, Claire L.; Gregg, Jillian W.; Wilson, John K.

    2011-11-01

    Daily minimum temperature (Tmin) has increased faster than daily maximum temperature (Tmax) in many parts of the world, leading to decreases in diurnal temperature range (DTR). Projections suggest these trends are likely to continue in many regions, particularly northern latitudes and in arid regions. Despite wide speculation that asymmetric warming has different impacts on plant and ecosystem production than equal-night-and-day warming, there has been little direct comparison of these scenarios. Reduced DTR has also been widely misinterpreted as a result of night-only warming, when in fact Tmin occurs near dawn, indicating higher morning as well as night temperatures. We reportmore » on the first experiment to examine ecosystem-scale impacts of faster increases in Tmin than Tmax, using precise temperature controls to create realistic diurnal temperature profiles with gradual day-night temperature transitions and elevated early morning as well as night temperatures. Studying a constructed grassland ecosystem containing species native to Oregon, USA, we found the ecosystem lost more carbon at elevated than ambient temperatures, but was unaffected by the 3ºC difference in DTR between symmetric warming (constantly ambient +3.5ºC) and asymmetric warming (dawn Tmin=ambient +5ºC, afternoon Tmax= ambient +2ºC). Reducing DTR had no apparent effect on photosynthesis, likely because temperatures were most different in the morning and late afternoon when light was low. Respiration was also similar in both warming treatments, because respiration temperature sensitivity was not sufficient to respond to the limited temperature differences between asymmetric and symmetric warming. We concluded that changes in daily mean temperatures, rather than changes in Tmin/Tmax, were sufficient for predicting ecosystem carbon fluxes in this reconstructed Mediterranean grassland system.« less

  14. Reduced diurnal temperature range does not change warming impacts on ecosystem carbon balance of Mediterranean grassland mesocosms

    SciTech Connect

    Phillips, Claire L.; Gregg, Jillian W.; Wilson, John K.

    2011-11-01

    Daily minimum temperature (Tmin) has increased faster than daily maximum temperature (Tmax) in many parts of the world, leading to decreases in diurnal temperature range (DTR). Projections suggest these trends are likely to continue in many regions, particularly northern latitudes and in arid regions. Despite wide speculation that asymmetric warming has different impacts on plant and ecosystem production than equal-night-and-day warming, there has been little direct comparison of these scenarios. Reduced DTR has also been widely misinterpreted as a result of night-only warming, when in fact Tmin occurs near dawn, indicating higher morning as well as night temperatures. We report on the first experiment to examine ecosystem-scale impacts of faster increases in Tmin than Tmax, using precise temperature controls to create realistic diurnal temperature profiles with gradual day-night temperature transitions and elevated early morning as well as night temperatures. Studying a constructed grassland ecosystem containing species native to Oregon, USA, we found the ecosystem lost more carbon at elevated than ambient temperatures, but was unaffected by the 3ºC difference in DTR between symmetric warming (constantly ambient +3.5ºC) and asymmetric warming (dawn Tmin=ambient +5ºC, afternoon Tmax= ambient +2ºC). Reducing DTR had no apparent effect on photosynthesis, likely because temperatures were most different in the morning and late afternoon when light was low. Respiration was also similar in both warming treatments, because respiration temperature sensitivity was not sufficient to respond to the limited temperature differences between asymmetric and symmetric warming. We concluded that changes in daily mean temperatures, rather than changes in Tmin/Tmax, were sufficient for predicting ecosystem carbon fluxes in this reconstructed Mediterranean grassland system.

  15. Are there evidences of altitudinal effects of air temperature trends in the European Alps 1820-2013?

    NASA Astrophysics Data System (ADS)

    Schoener, W.; Auer, I.; Chimani, B.; Garnekind, M.; Haslinger, K.

    2013-12-01

    We use the HISTALP data set (www.zamg.ac.at/histalp) in order to assess the elevation dependency of air temperature trends within the European Alps. The evidence of altitudinal effects of the climate warming (with higher sensitivity of high mountain regions to warming) is a key statement, or at least key hypothesis, in many studies. The high relevance of such statement resp. hypothesis is obvious if one consider the impacts resulting from such fact, such as snow- and glacier melting and related effects for mountain hydrology. The HISTALP data set stands out with respect to its series lengths and its high level of homogenisation. Interestingly, the HISTALP temperature data show no clear altitudinal dependency of warming or cooling trends within the period 1820-2013. Additionally, a rather homogenous temporal trend could be observed within the entire Greater Alpine Region (GAR). Because HISTALP include also air pressure and vapour pressure series, we could compare our measured air temperatures with mean-column air temperatures, computed by the barometric formula, which were derived from the independently measured air pressure data (using vapour pressure to account for the atmospheric water content) at low resp. high elevations. Computed mean column temperatures are in good agreement with observed temperatures, indicating generally homogenous temporal temperature trend behaviour at different elevations. Our finding contradicts several results from climate modelling attempts and also other studies investigating Alpine temperature trends. We conclude that, whereas modelling results are still limited in the assessment of altitudinal effect of temperature trends from missing atmospheric processes captured by the models, the difference of the trend behaviour compared to other analyses of instrumental air temperatures comes from the seasonal base taken as the basis for trend estimation. It appears that opposite trend in spring and autumn for the period 1980

  16. Warm molecular gas temperature distribution in six local infrared bright Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Pereira-Santaella, Miguel; Spinoglio, Luigi; van der Werf, Paul P.; Piqueras López, Javier

    2014-06-01

    We simultaneously analyze the spectral line energy distributions (SLEDs) of CO and H2 of six local luminous infrared (IR) Seyfert galaxies. For the CO SLEDs, we used new Herschel/SPIRE FTS data (from J = 4-3 to J = 13-12) and ground-based observations for the lower-J CO transitions. The H2 SLEDs were constructed using archival mid-IR Spitzer/IRS and near-IR VLT/SINFONI data for the rotational and ro-vibrational H2 transitions, respectively. In total, the SLEDs contain 26 transitions with upper level energies between 5 and 15 000 K. A single, constant density, model (nH2 ~ 104.5-6 cm-3) with a broken power-law temperature distribution reproduces well both the CO and H2 SLEDs. The power-law indices are β1 ~ 1-3 for warm molecular gas (20 K 100 K). We show that the steeper temperature distribution (higher β) for hot molecular gas can be explained by shocks and photodissociation region (PDR) models; however, the exact β values are not reproduced by PDR or shock models alone and a combination of both is needed. We find that the three major mergers among our targets have shallower temperature distributions for warm molecular gas than the other three spiral galaxies. This can be explained by a higher relative contribution of shock excitation, with respect to PDR excitation, for the warm molecular gas in these mergers. For only one of the mergers, IRASF 05189-2524, the shallower H2 temperature distribution differs from that of the spiral galaxies. The presence of a bright active galactic nucleus in this source might explain the warmer molecular gas observed. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  17. Long tails in regional surface temperature probability distributions with implications for extremes under global warming

    NASA Astrophysics Data System (ADS)

    Ruff, Tyler W.; Neelin, J. David

    2012-02-01

    Prior work has shown that probability distributions of column water vapor and several passive tropospheric chemical tracers exhibit longer-than-Gaussian (approximately exponential) tails. The tracer-advection prototypes explaining the formation of these long-tailed distributions motivate exploration of observed surface temperature distributions for non-Gaussian tails. Stations with long records in various climate regimes in National Climatic Data Center Global Surface Summary of Day observations are used to examine tail characteristics for daily average, maximum and minimum surface temperature probability distributions. Each is examined for departures from a Gaussian fit to the core (here approximated as the portion of the distribution exceeding 30% of the maximum). While the core conforms to Gaussian for most distributions, roughly half the cases exhibit non-Gaussian tails in both winter and summer seasons. Most of these are asymmetric, with a long, roughly exponential, tail on only one side. The shape of the tail has substantial implications for potential changes in extreme event occurrences under global warming. Here the change in the probability of exceeding a given threshold temperature is quantified in the simplest case of a shift in the present-day observed distribution. Surface temperature distributions with long tails have a much smaller change in threshold exceedances (smaller increases for high-side and smaller decreases for low-side exceedances relative to exceedances in current climate) under a given warming than do near-Gaussian distributions. This implies that models used to estimate changes in extreme event occurrences due to global warming should be verified regionally for accuracy of simulations of probability distribution tails.

  18. Infrared-warmed and un-warmed wheat vegetation indices coalesce using canopy-temperature-based growing degree days

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to determine the likely effects of global warming on field-grown wheat, a “Hot Serial Cereal” experiment was conducted -- so-called “Cereal” because wheat was the crop, “Serial” because the wheat was planted about every six weeks for two years, and “Hot” because infrared heaters were deploy...

  19. The local impact of southern Minnesota springtime lake temperature on warm-season surface meteorological parameters

    NASA Astrophysics Data System (ADS)

    Grimaldi, R. T.; Eberhard, M. J.; Phetteplace, B. B.

    2006-12-01

    Here, we investigate the relationship between late-spring lake surface temperatures in south-central Minnesota and surface wet-bulb potential temperatures in the Minneapolis/St. Paul area. We have identified six years in which the spring thaw of three local lakes occurred latest and six years in which the thaw occurred earliest since 1950. Early afternoon, wet-bulb potential temperatures from Minneapolis and St. Paul are compared to 700mb temperatures over the same region for the period May 10 to July 10. Results show, on average, there is a smaller difference between surface wet-bulb potential temperatures and 700mb temperatures for late thaw years. June surface temperatures average approximately 1 degree C cooler following a delayed thaw, thus providing additional support for a relationship between lake temperature and air temperature. However, the implied stabilization of the surface layer is found to have little if any effect upon thunderstorm activity in the region.

  20. Perioperative Warming in Surgical Patients: A Comparison of Interventions.

    PubMed

    Rowley, Brenda; Kerr, Marsi; Van Poperin, Judy; Everett, Cindy; Stommel, Manfred; Lehto, Rebecca H

    2015-08-01

    The four arm study investigates how use of a preoperative forced-air warming blanket and adjustment of ambient surgical room temperature may contribute to prevention of perioperative hypothermia. Active warming interventions may prevent the drop in core temperature that occur as a result of surgical anesthesia. Core body temperatures from a convenience sample of 220 adult surgical patients were sequentially monitored in the preoperative, intraoperative, and post-anesthesia care units (PACU) while receiving: (a) routine surgical care, (b) application of preoperative forced-air warming blanket, (c) application of preoperative forced-air warming blanket with adjustment of ambient surgical room temperatures, or (d) adjustment of ambient surgical room temperature only. Sample characteristics were evenly distributed among the four groups. There were no statistical differences in PACU core body temperatures. The application of forced-air warming blankets and room temperature adjustment interventions were not more effective than current practice in preventing perioperative hypothermia. PMID:24913925

  1. Warm temperature acclimation impacts metabolism of paralytic shellfish toxins from Alexandrium minutum in commercial oysters.

    PubMed

    Farrell, Hazel; Seebacher, Frank; O'Connor, Wayne; Zammit, Anthony; Harwood, D Tim; Murray, Shauna

    2015-09-01

    Species of Alexandrium produce potent neurotoxins termed paralytic shellfish toxins and are expanding their ranges worldwide, concurrent with increases in sea surface temperature. The metabolism of molluscs is temperature dependent, and increases in ocean temperature may influence both the abundance and distribution of Alexandrium and the dynamics of toxin uptake and depuration in shellfish. Here, we conducted a large-scale study of the effect of temperature on the uptake and depuration of paralytic shellfish toxins in three commercial oysters (Saccostrea glomerata and diploid and triploid Crassostrea gigas, n = 252 per species/ploidy level). Oysters were acclimated to two constant temperatures, reflecting current and predicted climate scenarios (22 and 27 °C), and fed a diet including the paralytic shellfish toxin-producing species Alexandrium minutum. While the oysters fed on A. minutum in similar quantities, concentrations of the toxin analogue GTX1,4 were significantly lower in warm-acclimated S. glomerata and diploid C. gigas after 12 days. Following exposure to A. minutum, toxicity of triploid C. gigas was not affected by temperature. Generally, detoxification rates were reduced in warm-acclimated oysters. The routine metabolism of the oysters was not affected by the toxins, but a significant effect was found at a cellular level in diploid C. gigas. The increasing incidences of Alexandrium blooms worldwide are a challenge for shellfish food safety regulation. Our findings indicate that rising ocean temperatures may reduce paralytic shellfish toxin accumulation in two of the three oyster types; however, they may persist for longer periods in oyster tissue. PMID:26032975

  2. Increasing influence of air temperature on upper Colorado River streamflow

    NASA Astrophysics Data System (ADS)

    Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory J.

    2016-03-01

    This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.

  3. Increasing influence of air temperature on upper Colorado River streamflow

    USGS Publications Warehouse

    Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory

    2016-01-01

    This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.

  4. Detection of recent regional sea surface temperature warming in the Caribbean and surrounding region

    NASA Astrophysics Data System (ADS)

    Glenn, Equisha; Comarazamy, Daniel; González, Jorge E.; Smith, Thomas

    2015-08-01

    We show a sea surface temperature (SST) warming trend for the Caribbean and surrounding region over 1982-2012. Using an optimum interpolated SST product, a 30 year climatological analysis was generated to observe annual, monthly, and seasonal trends. Results show that SSTs are increasing annually for the region. For the two Caribbean rainy seasons, the Early Rainfall Season (ERS) and the Late Rainfall Season (LRS), estimated trends at 0.0161°C yr-1 and 0.0209°C yr-1 were observed, with high statistical significance. Subregional analysis revealed that warming is greatest in the Gulf of Mexico and north of South America during the ERS and LRS. Additionally, LRS averages for 1998-2012 reflect an increase in magnitude and intensity of the Atlantic Warm Pool (AWP) since the 1983-1997 period reflected in the AWP Area Index. Extreme increases/decreases in the time series show potential correlation with El Niño and the Southern Oscillation.

  5. Crack growth behavior of warm-rolled 316L austenitic stainless steel in high-temperature hydrogenated water

    NASA Astrophysics Data System (ADS)

    Choi, Kyoung Joon; Yoo, Seung Chang; Jin, Hyung-Ha; Kwon, Junhyun; Choi, Min-Jae; Hwang, Seong Sik; Kim, Ji Hyun

    2016-08-01

    To investigate the effects of warm rolling on the crack growth of 316L austenitic stainless steel, the crack growth rate was measured and the oxide structure was characterized in high-temperature hydrogenated water. The warm-rolled specimens showed a higher crack growth rate compared to the as-received specimens because the slip bands and dislocations produced during warm rolling served as paths for corrosion and cracking. The crack growth rate increased with the dissolved hydrogen concentration. This may be attributed to the decrease in performance and stability of the protective oxide layer formed on the surface of stainless steel in high-temperature water.

  6. Linkage Between Hourly Precipitation Events and Atmospheric Temperature Changes over China during the Warm Season

    PubMed Central

    Miao, Chiyuan; Sun, Qiaohong; Borthwick, Alistair G. L.; Duan, Qingyun

    2016-01-01

    We investigated changes in the temporospatial features of hourly precipitation during the warm season over mainland China. The frequency and amount of hourly precipitation displayed latitudinal zonation, especially for light and moderate precipitation, which showed successive downward change over time in northeastern and southern China. Changes in the precipitation amount resulted mainly from changes in frequency rather than changes in intensity. We also evaluated the linkage between hourly precipitation and temperature variations and found that hourly precipitation extreme was more sensitive to temperature than other categories of precipitation. A strong dependency of hourly precipitation on temperature occurred at temperatures colder than the median daily temperature; in such cases, regression slopes were greater than the Clausius-Clapeyron (C-C) relation of 7% per degree Celsius. Regression slopes for 31.6%, 59.8%, 96.9%, and 99.1% of all stations were greater than 7% per degree Celsius for the 75th, 90th, 99th, and 99.9th percentiles for precipitation, respectively. The mean regression slopes within the 99.9th percentile of precipitation were three times the C-C rate. Hourly precipitation showed a strong negative relationship with daily maximum temperature and the diurnal temperature range at most stations, whereas the equivalent correlation for daily minimum temperature was weak. PMID:26931350

  7. Numerical and Experimental Investigation of Temperature Effect on Thickness Distribution in Warm Hydroforming of Aluminum Tubes

    NASA Astrophysics Data System (ADS)

    Hashemi, Seyed Jalal; Moslemi Naeini, Hassan; Liaghat, Gholamhosein; Azizi Tafti, Roohollah; Rahmani, Farzad

    2013-01-01

    Reduction of weight and increase of corrosion resistance are among the advantageous applications of aluminum alloys in automotive industry. Producing complicated components with several parts as a uniform part not only increases their strength but also decreases the production sequences and costs. However, achieving this purpose requires sufficient formability of the material. Tube hydroforming is an alternative process to produce complex products. In this process, the higher the material formability the more uniform will be the thickness distribution. In this research, tube hydroforming of aluminum alloy (AA1050) at various temperatures has been investigated numerically to study temperature effect on thickness distribution of final product. Also a warm hydroforming set-up has been designed and manufactured to evaluate numerical results. According to numerical and experimental results in the case of free bulging, unlike the constrained bulging, increase of the process temperature causes more uniform thickness distribution and therefore increases the material formability.

  8. Hardy exotics species in temperate zone: can "warm water" crayfish invaders establish regardless of low temperatures?

    PubMed

    Veselý, Lukáš; Buřič, Miloš; Kouba, Antonín

    2015-01-01

    The spreading of new crayfish species poses a serious risk for freshwater ecosystems; because they are omnivores they influence more than one level in the trophic chain and they represent a significant part of the benthic biomass. Both the environmental change through global warming and the expansion of the pet trade increase the possibilities of their spreading. We investigated the potential of four "warm water" highly invasive crayfish species to overwinter in the temperate zone, so as to predict whether these species pose a risk for European freshwaters. We used 15 specimens of each of the following species: the red swamp crayfish (Procambarus clarkii), the marbled crayfish (Procambarus fallax f. virginalis), the yabby (Cherax destructor), and the redclaw (Cherax quadricarinatus). Specimens were acclimatized and kept for 6.5 months at temperatures simulating the winter temperature regime of European temperate zone lentic ecosystems. We conclude that the red swamp crayfish, marbled crayfish and yabby have the ability to withstand low winter temperatures relevant for lentic habitats in the European temperate zone, making them a serious invasive threat to freshwater ecosystems. PMID:26572317

  9. Summertime Temperatures in Buildings Without Air-Conditioning.

    ERIC Educational Resources Information Center

    Loudon, A. G.

    Many modern buildings become uncomfortably warm during sunny spells in the summer, and until recently there was no simple, reliable method of assessing at the design stage whether a building would become overheated. This paper describes a method of calculating summertime temperatures which was developed at the Building Research Station, and gives…

  10. Projected increases in near-surface air temperature over Ontario, Canada: a regional climate modeling approach

    NASA Astrophysics Data System (ADS)

    Wang, Xiuquan; Huang, Guohe; Liu, Jinliang

    2015-09-01

    As the biggest economy in Canada, the Province of Ontario is now suffering many consequences caused by or associated with global warming, such as frequent and intense heat waves, floods, droughts, and wind gust. Planning of mitigation and adaptation strategies against the changing climate, which requires a better understanding of possible future climate outcomes over the Province in the context of global warming, is of great interest to local policy makers, stakeholders, and development practitioners. Therefore, in this study, high-resolution projections of near-surface air temperature outcomes including mean, maximum, and minimum daily temperature over Ontario are developed, aiming at investigating how the global warming would affect the local climatology of the major cities as well as the spatial patterns of air temperature over the entire Province. The PRECIS modeling system is employed to carry out regional climate ensemble simulations driven by the boundary conditions of a five-member HadCM3-based perturbed-physics ensemble (i.e., HadCM3Q0, Q3, Q10, Q13, and Q15). The ensemble simulations are then synthesized through a Bayesian hierarchical model to develop probabilistic projections of future temperature outcomes with consideration of some uncertain parameters involved in the regional climate modeling process. The results suggest that there would be a consistent increasing trend in the near-surface air temperature with time periods from 2030s to 2080s. The most likely mean temperature in next few decades (i.e., 2030s) would be [-2, 2] °C in northern Ontario, [2, 6] °C in the middle, and [6, 12] °C in the south, afterwards the mean temperature is likely to keep rising by ~ 2 °C per 30-years period. The continuous warming across the Province would drive the lowest mean temperature up to 2 °C in the north and the highest mean temperature up to 16 °C in the south. In addition, the spread of the most likely ranges of future outcomes shows a consistent

  11. Modeling Snowcover Sensitivity to Warming Temperature Across a Climatic Gradient in the Oregon Cascades

    NASA Astrophysics Data System (ADS)

    Cooper, M. G.; Sproles, E.; Nolin, A. W.; Rittger, K. E.; Painter, T. H.

    2013-12-01

    Warming winter temperatures will continue to shift precipitation from snow to rain, decreasing mountain snowpacks in temperature-sensitive regions such as the Pacific Northwest. Snow in the Oregon Cascades is particularly at risk because it falls at temperatures close to the melting point. The west side of the Oregon Cascades receives significantly more winter precipitation than the east side (2000 mm vs. 600 mm). While previous studies have focused on the west side of the Oregon Cascades, to date, no study has examined effects of warming temperature on snow over both the east and west sides of this mountain range. This study examines the effect of warming temperatures on present day and future patterns of snowpack accumulation and ablation in the headwater catchments of McKenzie (west side) and Metolius (east side) River Basins of the Oregon Cascades. This study employs a process-based, spatially distributed model, SnowModel, to quantify snow accumulation and ablation. We run the model at 100-m spatial scale on a daily time step, driving the model using spatially distributed meteorological data from stations in and around the sub-basins. The modeling period covers 1989-2009, during which time the region experienced high, low, and average snow water equivalent (SWE). For each basin, we quantify the date and magnitude of peak SWE, the date of snow disappearance, the ratio of SWE to winter precipitation (SWE:P), and the snow-covered area (SCA) at peak SWE for each year. We validate our model results using available SWE measurements and snow extent from Landsat remote sensing imagery. SnowModel is then run using perturbed meteorological input data (+1°C, +2°C, +3°C, +4°C and ×10% precipitation) to evaluate the potential effects of a warmer, wetter/drier winter climate on snowpack accumulation and melt in the watersheds. Simulations of SWE, precipitation, and temperature in the McKenzie Basin for the study period have Nash-Sutcliffe efficiencies of 0.83, 0.97, and

  12. Modulation of sea surface temperature warming in the Bay of Biscay by Loire and Gironde Rivers

    NASA Astrophysics Data System (ADS)

    Costoya, X.; Fernández-Nóvoa, D.; deCastro, M.; Santos, F.; Lazure, P.; Gómez-Gesteira, M.

    2016-01-01

    The influence of Loire and Gironde River discharges over the sea surface temperature (SST) in the eastern Bay of Biscay (0.6º-36.6ºW, 44.2º-47.8ºW) was analyzed by means of two complementary databases (MODIS and OISST1/4). The area influenced by river plume showed a different SST when compared with the adjacent oceanic area for the months when the plume attains its highest extension (December, January, and February). Ocean was observed to warm at a rate of approximately 0.3ºC dec-1 while temperature at the area influenced by the rivers cooled at a rate of -0.15ºC dec-1 over the period 1982-2014. The mere presence of a freshwater layer is able to modulate the warming observed at adjacent ocean locations since the coastal area is isolated from the rest of the Bay. This nearshore strip is the only part of the Bay where changes in SST depend on North Atlantic Oscillation (NAO) but not on North Atlantic SST represented by the Atlantic Multidecadal Oscillation (AMO). These different cooling-warming trends are even more patent over the last years (2002-2014) under atmospheric favorable conditions for plume enhancement. River runoff increased at a rate on the order of 120 m3s-1dec-1 over that period and southwesterly winds, which favor the confinement of the plume, showed a positive and significant trend both in duration and intensity. Thus, the coastal strip has been observed to cool at a rate of -0.5°C dec-1.

  13. Recent trends in regional air temperature and precipitation and links to global climate change in the Maharlo watershed, Southwestern Iran

    NASA Astrophysics Data System (ADS)

    Abolverdi, Javad; Ferdosifar, Ghasem; Khalili, Davar; Kamgar-Haghighi, Ali Akbar; Abdolahipour Haghighi, Mohammad

    2014-11-01

    Trends in air temperature and precipitation data are investigated for linkages to global warming and climate change. After checking for serial correlation with trend-free pre-whitening procedure, the Mann-Kendall test is used to detect monotonic trends and the Mann-Whitney test is used for trend step change. The case study is Maharlo watershed, Southwestern Iran, representing a semi-arid environment. Data are for the 1951-2011 period, from four temperature sites and seven precipitation sites. A homogeneity test investigates regional similarity of the time series data. The results include mean annual, mean annual maximum and minimum and seasonal analysis of air temperature and precipitation data. Mean annual temperature results indicate an increasing trend, while a non-significant trend in precipitation is observed in all the stations. Furthermore, significant phase change was detected in mean annual air temperature trend of Shiraz station in 1977, indicating decreasing trend during 1951-1976 and increasing trend during 1977-2011. The annual precipitation analysis for Shiraz shows a non-significant decrease during 1951-1976 and 1977-2011. The result of homogeneity test reveals that the studied stations form one homogeneous region. While air temperature trends appear as regional linkage to global warming/global climate change, more definite outcome requires analysis of longer time series data on precipitation and air temperature.

  14. Biases in the air-sea flux of CO2 resulting from ocean surface temperature gradients

    NASA Astrophysics Data System (ADS)

    Ward, B.; Wanninkhof, R.; McGillis, W. R.; Jessup, A. T.; Degrandpre, M. D.; Hare, J. E.; Edson, J. B.

    2004-08-01

    The difference in the fugacities of CO2 across the diffusive sublayer at the ocean surface is the driving force behind the air-sea flux of CO2. Bulk seawater fugacity is normally measured several meters below the surface, while the fugacity at the water surface, assumed to be in equilibrium with the atmosphere, is measured several meters above the surface. Implied in these measurements is that the fugacity values are the same as those across the diffusive boundary layer. However, temperature gradients exist at the interface due to molecular transfer processes, resulting in a cool surface temperature, known as the skin effect. A warm layer from solar radiation can also result in a heterogeneous temperature profile within the upper few meters of the ocean. Here we describe measurements carried out during a 14-day study in the equatorial Pacific Ocean (GasEx-2001) aimed at estimating the gradients of CO2 near the surface and resulting flux anomalies. The fugacity measurements were corrected for temperature effects using data from the ship's thermosalinograph, a high-resolution profiler (SkinDeEP), an infrared radiometer (CIRIMS), and several point measurements at different depths on various platforms. Results from SkinDeEP show that the largest cool skin and warm layer biases occur at low winds, with maximum biases of -4% and +4%, respectively. Time series ship data show an average CO2 flux cool skin retardation of about 2%. Ship and drifter data show significant CO2 flux enhancement due to the warm layer, with maximums occurring in the afternoon. Temperature measurements were compared to predictions based on available cool skin parameterizations to predict the skin-bulk temperature difference, along with a warm layer model.

  15. Changes in winter air temperatures near Lake Michigan, 1851-1993, as determined from regional lake-ice records

    USGS Publications Warehouse

    Assel, R.A.; Robertson, Dale M.

    1995-01-01

    Records of freezeup and breakup dates for Grand Traverse Bay, Michigan, and Lake Mendota, Wisconsin, are among the longest ice records available near the Great Lakes, beginning in 185 1 and 1855, respectively. The timing of freezeup and breakup results from an integration of meteorological conditions (primarily air temperature) that occur before these events. Changes in the average timing of these ice-events are translated into changes in air temperature by the use of empirical and process-driven models. The timing of freezeup and breakup at the two locations represents an integration of air temperatures over slightly different seasons (months). Records from both locations indicate that the early winter period before about 1890 was - 15°C cooler than the early winter period after that time; the mean temperature has, however, remained relatively constant since about 1890. Changes in breakup dates demonstrate a similar 1.0-1 .5”C increase in late winter and early spring air temperatures about 1890. More recent average breakup dates at both locations have been earlier than during 1890-1940, indicating an additional warming of 1.2”C in March since about 1940 and a warming of 1 . 1°C in January-March since about 1980. Ice records at these sites will continue to provide an early indication of the anticipated climatic warming, not only because of the large response of ice cover to small changes in air temperature but also because these records integrate climatic conditions during the seasons (winter-spring) when most warming is forecast to occur. Future reductions in ice cover may strongly affect the winter ecology of the Great Lakes by reducing the stable environment required by various levels of the food chain. 

  16. Medieval Warm Period, Little Ice Age and 20th century temperature variability from Chesapeake Bay

    USGS Publications Warehouse

    Cronin, T. M.; Dwyer, G.S.; Kamiya, T.; Schwede, S.; Willard, D.A.

    2003-01-01

    We present paleoclimate evidence for rapid (< 100 years) shifts of ??? 2-4??C in Chesapeake Bay (CB) temperature ???2100, 1600, 950, 650, 400 and 150 years before present (years BP) reconstructed from magnesium/calcium (Mg/Ca) paleothermometry. These include large temperature excursions during the Little Ice Age (???1400-1900 AD) and the Medieval Warm Period (???800-1300 AD) possibly related to changes in the strength of North Atlantic thermohaline circulation (THC). Evidence is presented for a long period of sustained regional and North Atlantic-wide warmth with low-amplitude temperature variability between ???450 and 1000 AD. In addition to centennial-scale temperature shifts, the existence of numerous temperature maxima between 2200 and 250 years BP (average ???70 years) suggests that multi-decadal processes typical of the North Atlantic Oscillation (NAO) are an inherent feature of late Holocene climate. However, late 19th and 20th century temperature extremes in Chesapeake Bay associated with NAO climate variability exceeded those of the prior 2000 years, including the interval 450-1000 AD, by 2-3??C, suggesting anomalous recent behavior of the climate system. ?? 2002 Elsevier Science B.V. All rights reserved.

  17. Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

    2010-01-01

    Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

  18. Characteristics of the Dominant Frequency of West Pacific Warm Pool Subsurface Temperature in Response to ENSO Events.

    NASA Astrophysics Data System (ADS)

    Park, G. S.; Lee, D. K.; Jo, Y. H.

    2014-12-01

    West Pacific Warm Pool (WPWP) is the warm water body confined by Sea Surface Temperature (SST) over 28°C. The most important role of WPWP in response to air-sea interactions is that El-Niño and La-Niña events are determined by WPWP's zonal migration. Many researches have conducted to understand the relationship between ENSO events and WPWP changes, but research for Subsurface Temperature (ST) fluctuation by WPWP's movement does not well understood due to deficiency of observations, which is the main motivation of this research. This research based on ARGO's float profile subsurface data and TAO/TRITON's mooring subsurface data. Especially, our research results are based on ST from surface to 500m depth and estimated ST deviation in route of eastbound WPWP between north and south 10° by the Pacific equatorial line to identify ENSO events. The El-Niño and La-Niña events were defined by Multivariate ENSO Index (MEI) and then, we computed certain frequencies of ST under each condition, respectively. In order to understand the dominant frequency of ST, Ensemble Empirical Mode Decomposition (EEMD) was used. EEMD is analysis method to add Gaussian white noise in signal to redeem weak point of analysis method to non-linear and non-stationary signal. The research result shows that during normal condition, ST deviation values in Eastern Pacific (EP) had lower than those of Western Pacific (WP). During El-Niño condition, ST deviation values in the EP was higher than the normal condition, and ST deviation values in the WP was lower than normal condition and higher frequency in temperature fluctuation. During La-Niña condition, EP had similar ST amplitude with normal condition, but ST deviation values in the WP was so lower than the normal condition and fluctuation frequency was lower, too. So, we could understand that our estimations are resulting from intensified ST difference between high temperature of WPWP and low temperature of subsurface in location of WPWP

  19. Long-range Memory in Earth's Global Temperature and its Implications for Future Global Warming

    NASA Astrophysics Data System (ADS)

    Rypdal, K.; Oestvand, L.

    2012-12-01

    The Earth's climate is a driven complex system which responds to a variable radiative forcing on a vast range of time scales. The contribution explores the hypothesis that the temporal global temperature response can be modeled as a long-range memory (LRM) stochastic process characterized by a Hurst exponent 0.5temperature records we verify LRM scaling on time scales from months to several decades. We find that the LRM increases when one goes from regional (H= 0.7) to global (H=1.0) records and that LRM is highest in records strongly influenced by the ocean. The increasing trend through the last century cannot be explained as an unforced LRM fluctuation, but the observed 60-yr oscillation can. Analysis of a northern-hemisphere reconstruction for the last two millennia confirms LRM scaling up to at least 250 yr. If this record reconstructs the milennium-scale temperatures correctly there is a significant temperature difference between the Medieval Warm Period and the Little Ice Age which cannot be explained as an inherent LRM fluctuation. We systematically investigate biases and uncertainties of a number of analysis methods, and conclude that for these record lengths it has no meaning to give Hurst exponents with more than one decimal. We also address the serious implications of such memory effects on future global warming due to the stronger disturbance of the Earth's energy balance under sustained forcing.

  20. Acclimation of photosynthetic temperature optima of temperate and boreal tree species in response to experimental forest warming.

    PubMed

    Sendall, Kerrie M; Reich, Peter B; Zhao, Changming; Jihua, Hou; Wei, Xiaorong; Stefanski, Artur; Rice, Karen; Rich, Roy L; Montgomery, Rebecca A

    2015-03-01

    Rising temperatures caused by climate change could negatively alter plant ecosystems if temperatures exceed optimal temperatures for carbon gain. Such changes may threaten temperature-sensitive species, causing local extinctions and range migrations. This study examined the optimal temperature of net photosynthesis (Topt ) of two boreal and four temperate deciduous tree species grown in the field in northern Minnesota, United States under two contrasting temperature regimes. We hypothesized that Topt would be higher in temperate than co-occurring boreal species, with temperate species exhibiting greater plasticity in Topt , resulting in better acclimation to elevated temperatures. The chamberless experiment, located at two sites in both open and understory conditions, continuously warmed plants and soils during three growing seasons. Results show a modest, but significant shift in Topt of 1.1 ± 0.21 °C on average for plants subjected to a mean 2.9 ± 0.01 °C warming during midday hours in summer, and shifts with warming were unrelated to species native ranges. The 1.1 °C shift in Topt with 2.9 °C warming might be interpreted as suggesting limited capacity to shift temperature response functions to better match changes in temperature. However, Topt of warmed plants was as well-matched with prior midday temperatures as Topt of plants in the ambient treatment, and Topt in both treatments was at a level where realized photosynthesis was within 90-95% of maximum. These results suggest that seedlings of all species were close to optimizing photosynthetic temperature responses, and equally so in both temperature treatments. Our study suggests that temperate and boreal species have considerable capacity to match their photosynthetic temperature response functions to prevailing growing season temperatures that occur today and to those that will likely occur in the coming decades under climate change. PMID:25354151

  1. Air Temperature Evolution for the Last 10 Years in the National Petroleum Reserve Alaska

    NASA Astrophysics Data System (ADS)

    Vas, D. A.; Toniolo, H. A.; Kemnitz, R.; Bailey, J. P.

    2014-12-01

    The National Petroleum Reserve-Alaska (NPR-A), an area of approximately 23 million acres, extends from the north side of the Brooks Range to the Arctic Ocean. The Bureau of Land Management (BLM), as a part of studies focused on establishing baseline conditions for weather and hydrological parameters, installed six weather and gauging stations along the NPR-A. This work concentrates on weather conditions, specifically air temperature. Data collected in each of these sites include air temperature (in all the stations), while summer precipitation and wind parameters were collected only at three stations. We present an initial summary of air temperature evolution in the stations, from the installation of each site to September 30, 2013. Available information indicates that the entire region followed a pronounced warming trend, finishing with the 2010/2011 winter, which was the warmest winter recorded in each station. A nearly 20 percent increase in annual cumulative freezing degree days (ACFDD) occurred between the 2011/2012 and 2012/2013 winters. A preliminary analysis of air temperature on a monthly basis shows that, in general, the months of January and March of 2012 contributed the most to the increase in the ACFDD. In particular, the mean monthly temperature in March was in the vicinity of -35 °C in all the stations, which certainly marked 2012 as the coldest March on record.

  2. The impact of different cooling strategies on urban air temperatures: the cases of Campinas, Brazil and Mendoza, Argentina

    NASA Astrophysics Data System (ADS)

    Alchapar, Noelia Liliana; Cotrim Pezzuto, Claudia; Correa, Erica Norma; Chebel Labaki, Lucila

    2016-07-01

    This paper describes different ways of reducing urban air temperature and their results in two cities: Campinas, Brazil—a warm temperate climate with a dry winter and hot summer (Cwa), and Mendoza, Argentina—a desert climate with cold steppe (BWk). A high-resolution microclimate modeling system—ENVI-met 3.1—was used to evaluate the thermal performance of an urban canyon in each city. A total of 18 scenarios were simulated including changes in the surface albedo, vegetation percentage, and the H/W aspect ratio of the urban canyons. These results revealed the same trend in behavior for each of the combinations of strategies evaluated in both cities. Nevertheless, these strategies produce a greater temperature reduction in the warm temperate climate (Cwa). Increasing the vegetation percentage reduces air temperatures and mean radiant temperatures in all scenarios. In addition, there is a greater decrease of urban temperature with the vegetation increase when the H/W aspect ratio is lower. Also, applying low albedo on vertical surfaces and high albedo on horizontal surfaces is successful in reducing air temperatures without raising the mean radiant temperature. The best combination of strategies—60 % of vegetation, low albedos on walls and high albedos on pavements and roofs, and 1.5 H/W—could reduce air temperatures up to 6.4 °C in Campinas and 3.5 °C in Mendoza.

  3. Annual and seasonal air temperature trend patterns of climate change and urbanization effects in relation to air pollutants in Turkey

    NASA Astrophysics Data System (ADS)

    Tayanç, Mete; Karaca, Mehmet; Yenigün, Orhan

    1997-01-01

    With a view to estimating climate change and ifs urban-induced bias in selected Turkish cities, we have used data from the period 1951 to 1990 recorded by 54 climate stations, four of which are corrected for their inhomogeneities. Two sets are produced; S1, including the large urban stations, and S2, consisting of rural, small urban and medium urban stations. Normalized Kendall trend test coefficients with a spatial prediction scheme, kriging, are used to construct spatial patterns of both sets together and separately. Results reveal a statistically significant cooling in mean temperatures mostly in northern regions and warming in minimum temperatures specific to large urban areas. Seasonal analysis shows that most of this cooling has been occurring in the summer and urban warming in the spring. The causes of cooling is investigated in relation to some air pollutants, SO2 and particulate matter (PM). Linear regressions performed on the time series resulted in a significant urban bias of 0.24°C per 40 years on mean temperatures and 0.56°C/40 years on minimum temperatures. In association with the above results, a decrease in the temperature range of 0.48°C over the period owing to urban bias was found. A 0.24°C urban bias magnitude of mean temperature trends is much greater than the results found on other three regions of the Earth [Jones et al., 1990]. An overall average cooling in mean temperatures, -0.07°C per decade, detected here is the same as Nasrallah and Balling's [1993] average result for the two grid points located over Turkey.

  4. Recent changes in Arctic temperature extremes: warm and cold spells during winter and summer

    NASA Astrophysics Data System (ADS)

    Matthes, Heidrun; Rinke, Annette; Dethloff, Klaus

    2015-11-01

    In the Arctic, climate change manifests with the strongest warming trends on the globe, especially in the cold season. It is under debate if climate extremes change similarly strong. Our study provides detailed regional information about two selected temperature extreme indices in the Arctic, namely warm and cold spells in winter and summer. We analyze their temporal evolution and variability from 1979-2013, based on daily station data and ERA-Interim reanalysis. Calculated trends from both datasets suggest a widespread decrease of cold spells in winter and summer of up to -4 days/decade, with regional patches where trends are statistically significant throughout the Arctic. Winter trends are spatially heterogeneous, the reanalysis also shows small areas with statistically significant increases of cold spells throughout Siberia. Calculated changes in warm spells from both datasets are mostly small throughout the Arctic (less than ±1 day/decade) and statistically not significant. Remarkable exceptions are the Lena river basin in winter with a statistically significant decrease of up to -1.5 days/decade and areas in Scandinavia with statistically significant increases of up to 2.5 days/decade in winter and summer (again from both datasets). From the analysis of spell lengths, we find that there are no shifts from longer to shorter spells or vice versa with time, but long cold spells (events lasting for more than 15 days) disappear almost completely after the year 2000. There is a distinct inter-annual and decadal variability in the spells, which hinders the detection of significant trends for all spell categories in all regions.

  5. Characterizing Air Temperature Changes in the Tarim Basin over 1960–2012

    PubMed Central

    Peng, Dongmei; Wang, Xiujun; Zhao, Chenyi; Wu, Xingren; Jiang, Fengqing; Chen, Pengxiang

    2014-01-01

    There has been evidence of warming rate varying largely over space and between seasons. However, little has been done to evaluate the spatial and temporal variability of air temperature in the Tarim Basin, northwest China. In this study, we collected daily air temperature from 19 meteorological stations for the period of 1960–2012, and analyzed annual mean temperature (AMT), the annual minimum (Tmin) and maximum temperature (Tmax), and mean temperatures of all twelve months and four seasons and their anomalies. Trend analyses, standard deviation of the detrended anomaly (SDDA) and correlations were carried out to characterize the spatial and temporal variability of various mean air temperatures. Our data showed that increasing trend was much greater in the Tmin (0.55°C/10a) than in the AMT (0.25°C/10a) and Tmax (0.12°C/10a), and the fluctuation followed the same order. There were large spatial variations in the increasing trends of both AMT (from −0.09 to 0.43 °C/10a) and Tmin (from 0.15 to 1.12°C/10a). Correlation analyses indicated that AMT had a significantly linear relationship with Tmin and the mean temperatures of four seasons. There were also pronounced changes in the monthly air temperature from November to March at decadal time scale. The seasonality (i.e., summer and winter difference) of air temperature was stronger during the period of 1960–1979 than over the recent three decades. Our preliminary analyses indicated that local environmental conditions (such as elevation) might be partly responsible for the spatial variability, and large scale climate phenomena might have influences on the temporal variability of air temperature in the Tarim Basin. In particular, there was a significant correlation between index of El Niño-Southern Oscillation (ENSO) and air temperature of May (P = 0.004), and between the index of Pacific Decadal Oscillation (PDO) and air temperature of July (P = 0.026) over the interannual to decadal time scales. PMID

  6. Characterizing air temperature changes in the Tarim Basin over 1960-2012.

    PubMed

    Peng, Dongmei; Wang, Xiujun; Zhao, Chenyi; Wu, Xingren; Jiang, Fengqing; Chen, Pengxiang

    2014-01-01

    There has been evidence of warming rate varying largely over space and between seasons. However, little has been done to evaluate the spatial and temporal variability of air temperature in the Tarim Basin, northwest China. In this study, we collected daily air temperature from 19 meteorological stations for the period of 1960-2012, and analyzed annual mean temperature (AMT), the annual minimum (T min) and maximum temperature (Tmax), and mean temperatures of all twelve months and four seasons and their anomalies. Trend analyses, standard deviation of the detrended anomaly (SDDA) and correlations were carried out to characterize the spatial and temporal variability of various mean air temperatures. Our data showed that increasing trend was much greater in the T min (0.55°C/10a) than in the AMT (0.25°C/10a) and Tmax (0.12°C/10a), and the fluctuation followed the same order. There were large spatial variations in the increasing trends of both AMT (from -0.09 to 0.43 °C/10a) and T min (from 0.15 to 1.12°C/10a). Correlation analyses indicated that AMT had a significantly linear relationship with T min and the mean temperatures of four seasons. There were also pronounced changes in the monthly air temperature from November to March at decadal time scale. The seasonality (i.e., summer and winter difference) of air temperature was stronger during the period of 1960-1979 than over the recent three decades. Our preliminary analyses indicated that local environmental conditions (such as elevation) might be partly responsible for the spatial variability, and large scale climate phenomena might have influences on the temporal variability of air temperature in the Tarim Basin. In particular, there was a significant correlation between index of El Niño-Southern Oscillation (ENSO) and air temperature of May (P = 0.004), and between the index of Pacific Decadal Oscillation (PDO) and air temperature of July (P = 0.026) over the interannual to decadal time scales. PMID:25375648

  7. Solar Eclipse Effect on Shelter Air Temperature

    NASA Technical Reports Server (NTRS)

    Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

    1996-01-01

    Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

  8. Atmospheric forcing intensifies the effects of regional ocean warming on reef-scale temperature anomalies during a coral bleaching event

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenlin; Falter, James; Lowe, Ryan; Ivey, Greg; McCulloch, Malcolm

    2013-09-01

    We investigate how local atmospheric conditions and hydrodynamic forcing contributed to local variations in water temperature within a fringing coral reef-lagoon system during the peak of a marine heat wave in 2010-2011 that caused mass coral bleaching across Western Australia. A three-dimensional circulation model Regional Ocean Modeling System (ROMS) with a built-in air-sea heat flux exchange module Coupled Ocean Atmosphere Experiment (COARE) was coupled with a spectral wave model Simulating Waves Nearshore (SWAN) to resolve the surface heat exchange and wave-driven reef circulation in Coral Bay, Ningaloo Reef. Using realistic oceanic and atmospheric forcing, the model predictions were in good agreement with measured time series of water temperature at various locations in the coral reef system during the bleaching event. Through a series of sensitivity analyses, we found that the difference in temperature between the reef and surrounding offshore waters (ΔT) was predominantly a function of both the daily mean net heat flux (Qnet>¯) and residence time, whereas diurnal variations in reef water temperature were dependent on the diurnal fluctuation in the net heat flux. We found that reef temperatures were substantially higher than offshore in the inner lagoon under normal weather conditions and over the entire reef domain under more extreme weather conditions (0.7°C-1.5°C). Although these temperature elevations were still less than that caused by the regional ocean warming (2°C-3°C), the arrival of peak seasonal temperatures in the summer of 2010-2011 (when net atmospheric heat fluxes were positive and abnormally high) caused substantially higher thermal stresses than would have otherwise occurred if offshore temperatures had reached their normal seasonal maxima in autumn (when net atmospheric heat fluxes were negative or cooling). Therefore, the degree heating weeks calculated based on offshore temperature substantially underestimated the thermal stresses

  9. Simultaneous microwave measurements of middle atmospheric ozone and temperature during sudden stratospheric warming

    NASA Astrophysics Data System (ADS)

    Kulikov, M. Y.; Krasil'nikov, A. A.; Shvetsov, A. A.; Mukhin, D. N.; Fedoseev, L. I.; Ryskin, V. G.; Belikovich, M. V.; Karashtin, D. A.; Kukin, L. M.; Feigin, A. M.

    2012-04-01

    At the present time we carry out the experimental campaign aimed to study the response of middle atmosphere on current sudden stratospheric warming above Nizhny Novgorod, Russia (56N, 44E). The equipment consists of two room-temperature radiometers which specially have been designed to detect emission ozone line at 110.8 GHz and atmospheric radiation in the frequency range 52.5 - 54.5 GHz accordingly. Two digital fast Fourier transform spectroanalyzers developed by "Acqiris" are employed for signal analysis in the intermediate frequency range 0.05-1 GHz with the effective resolution 61 KHz. For retrieval vertical profiles of ozone and temperature from radiometric data we apply novel method based on Bayesian approach to inverse problems which assumes a construction of probability distribution of the characteristics of retrieved profiles with taking into account measurement noise and available a priori information about possible distributions of ozone and temperature in the middle atmosphere. Here we are going to introduce the fist results of the campaign in comparison with Aura MLS data and temperature maps from High Resolution Transport Model MIMOSA. The work was done under support of the RFBR (projects 11-05-97050 and 12-05-00999).

  10. Provenance-specific growth responses to drought and air warming in three European oak species (Quercus robur, Q. petraea and Q. pubescens).

    PubMed

    Arend, Matthias; Kuster, Thomas; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias

    2011-03-01

    Provenance-specific growth responses to experimentally applied drought and air warming were studied in saplings of three European oak species: Quercus robur, Quercus petraea and Quercus pubescens. Four provenances of each species were grown in large open-top chambers and subjected to four climates: control, periodic drought, air warming or their combination in 3 subsequent years. Overall growth responses were found among species and provenances, with drought reducing shoot height growth and stem diameter growth and air warming stimulating shoot height growth but reducing stem diameter growth and root length growth. Differential growth responses in shoots, stems and roots resulted in altered allometric growth relations. Root length growth to shoot height growth increased in response to drought but decreased in response to air warming. Stem diameter growth to shoot height growth decreased in response to air warming. The growth responses in shoots and stems were highly variable among provenances indicating provenance-specific sensitivity to drought and air warming, but this response variability did not reflect local adaptation to climate conditions of provenance origin. Shoot height growth was found to be more sensitive to drought in provenances from northern latitudes than in provenances from southern latitudes, suggesting that genetic factors related to the postglacial immigration history of European oaks might have interfered with selective pressure at provenance origins. PMID:21422189

  11. Effect of drink temperature on core temperature and endurance cycling performance in warm, humid conditions.

    PubMed

    Burdon, Catriona; O'Connor, Helen; Gifford, Janelle; Shirreffs, Susan; Chapman, Phillip; Johnson, Nathan

    2010-09-01

    The aims of this study were to determine the effect of cold (4 °C) and thermoneutral (37 °C) beverages on thermoregulation and performance in the heat and to explore sensory factors associated with ingesting a cold stimulus. Seven males (age 32.8 ± 6.1 years, [V(.)]O(2peak) 59.4 ± 6.6 ml x kg(-1) x min(-1)) completed cold, thermoneutral, and thermoneutral + ice trials in randomized order. Participants cycled for 90 min at 65%[V(.)]O(2peak) followed by a 15-min performance test at 28 °C and 70% relative humidity. They ingested 2.3 ml x kg(-1) of a 7.4% carbohydrate-electrolyte solution every 10 min during the 90-min steady-state exercise including 30 ml ice puree every 5 min in the ice trial. Absolute changes in skin temperature (0.22 ± 1.1 °C vs. 1.14 ± 0.9 °C; P = 0.02), mean body temperature (1.2 ± 0.3 vs. 1.6 ± 0.3 °C; P = 0.03), and heat storage were lower across the 90-min exercise bout for the cold compared with the thermoneutral trial. Significant improvements (4.9 ± 2.4%, P < 0.01) in performance were observed with cold but no significant differences were detected with ice. Consumption of cold beverages during prolonged exercise in the heat improves body temperature measures and performance. Consumption of ice did not reveal a sensory response, but requires further study. Beverages consumed by athletes exercising in the heat should perhaps be cold for performance and safety reasons. PMID:20694887

  12. The time of day effects of warm temperature on flowering time involve PIF4 and PIF5

    PubMed Central

    Thines, Bryan C.; Duarte, Maritza I.; Harmon, Frank G.

    2014-01-01

    Warm temperature promotes flowering in Arabidopsis thaliana and this response involves multiple signalling pathways. To understand the temporal dynamics of temperature perception, tests were carried out to determine if there was a daily window of enhanced sensitivity to warm temperature (28 °C). Warm temperature applied during daytime, night-time, or continuously elicited earlier flowering, but the effects of each treatment were unequal. Plants exposed to warm night (WN) conditions flowered nearly as early as those in constant warm (CW) conditions, while treatment with warm days (WD) caused later flowering than either WN or CW. Flowering in each condition relied to varying degrees on the activity of CO , FT , PIF4 , and PIF5 , as well as the action of unknown genes. The combination of signalling pathways involved in flowering depended on the time of the temperature cue. WN treatments caused a significant advance in the rhythmic expression waveform of CO, which correlated with pronounced up-regulation of FT expression, while WD caused limited changes in CO expression and no stimulation of FT expression. WN- and WD-induced flowering was partially CO independent and, unexpectedly, dependent on PIF4 and PIF5 . pif4-2, pif5-3, and pif4-2 pif5-3 mutants had delayed flowering under all three warm conditions. The double mutant was also late flowering in control conditions. In addition, WN conditions alone imposed selective changes to PIF4 and PIF5 expression. Thus, the PIF4 and PIF5 transcription factors promote flowering by at least two means: inducing FT expression in WN and acting outside of FT by an unknown mechanism in WD. PMID:24574484

  13. Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

    NASA Technical Reports Server (NTRS)

    Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

    2014-01-01

    The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

  14. Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

    2013-04-01

    Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

  15. Predicting canopy temperatures and infrared heater energy requirements for warming field plots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Warming open-field plots using arrays of infrared heaters has proven feasible for conducting experiments to determine the likely effects of global warming on various ecosystems. To date, however, such experiments have been done for only a few degrees (= 3.5°C) of warming, yet climate projections, es...

  16. Global warming and coral reefs: modelling the effect of temperature on Acropora palmata colony growth.

    PubMed

    Crabbe, M James C

    2007-08-01

    Data on colony growth of the branching coral Acropora palmata from fringing reefs off Discovery Bay on the north coast of Jamaica have been obtained over the period 2002-2007 using underwater photography and image analysis by both SCUBA and remotely using an ROV incorporating twin lasers. Growth modelling shows that while logarithmic growth is an approximate model for growth, a 3:3 rational polynomial function provides a significantly better fit to growth data for this coral species. Over the period 2002-2007, involving several cycles of sea surface temperature (SST) change, the rate of growth of A. palmata was largely proportional to rate of change of SST, with R(2)=0.935. These results have implications for the influence of global warming and climate change on coral reef ecosystems. PMID:17631417

  17. Recent Warming of Lake Kivu

    PubMed Central

    Katsev, Sergei; Aaberg, Arthur A.; Crowe, Sean A.; Hecky, Robert E.

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730

  18. Associations of endothelial function and air temperature in diabetic subjects

    EPA Science Inventory

    Background and Objective: Epidemiological studies consistently show that air temperature is associated with changes in cardiovascular morbidity and mortality. However, the biological mechanisms underlying the association remain largely unknown. As one index of endothelial functio...

  19. [Effect of air temperature and rainfall on wetland ecosystem CO2 exchange in China].

    PubMed

    Chu, Xiao-jing; Han, Guang-xuan

    2015-10-01

    Wetland can be a potential efficient sink to reduce global warming due to its higher primary productivity and lower carbon decomposition rate. While there has been a series progress on the influence mechanism of ecosystem CO2 exchange over China' s wetlands, a systematic metaanalysis of data still needs to be improved. We compiled data of ecosystem CO2 exchange of 21 typical wetland vegetation types in China from 29 papers and carried out an integrated analysis of air temperature and precipitation effects on net ecosystem CO2 exchange (NEE), ecosystem respiration (Reco), gross primary productivity (GPP), the response of NEE to PAR, and the response of Reco to temperature. The results showed that there were significant responses (P<0.05) of NEE (R2 = 50%, R2=57%), GPP (R2 = 60%, R2 = 50%) Reco (R2 = 44%, R2=50%) with increasing air temperature and enhanced precipitation on the annual scale. On the growing season scale, air temperature accounted for 50% of the spatial variation of NEE, 36% of GPP and 19% of Reco, respectively. Both NEE (R2 = 33%) and GPP (R2 =25%) were correlated positively with precipitation (P<0.05). However, the relationship between Reco and precipitation was not significant (P>0.05). Across different Chinese wetlands, both precipitation and temperature had no significant effect on apparent quantum yield (α) or ecosystem respiration in the daytime (Reco,day, P>0.05). The maximum photosynthesis rate (Amax) was remarkably correlated with precipitation (P <0.01), but not with air temperature. Besides, there was no significant correlation between basal respiration (Rref) and precipitation (P>0.05). Precipitation was negatively correlated with temperature sensitivity of Reco (Q10, P<0.05). Furthermore, temperature accounted for 35% and 46% of the variations in temperature sensitivity of Reco (Q10) and basal respiration (Rref P<0.05), respectively. PMID:26995905

  20. Response of Surface Temperature and Precipitation over Ecotone in Northern China to the Global Warming during 1964-2013

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Wei, Z.; Dong, W.; Zheng, Z.

    2015-12-01

    Based on observed temperature and precipitation data in the period of 1964-2013 from China Meteorological Administration (CMA), the climate response of ecotone in Northern China were analyzed in this paper. The result shows that: ecotone of northern China can be divided into 4 regions using the rotated empirical orthogonal decomposition (REOF):northwest region, north region, the southern section of the northeast region, and the northern section of the northeast region. During recent 50 years, ecotone of northern China experienced a significant warming(0.41℃/10a) compared to the warming over china(0.39℃/10a) and the warming around the world(0.15℃/10a), which is mainly contributed by minimum temperature increasing and cold season warming. The surface temperature showed declined during 1964-1969 but shifted to accelerating warming in 1970s-1990s(0.55℃/10a), and started to cooling since 2000s(-0.68℃/10a), which indicates the temperature of ecotone in Northern China has experienced a warming hiatus resembled to the global warming hiatus since 2000s, while it has decreased much more. Besides, the annual precipitation dropped about 13mm during 1964-2013 overall, of which the north region has declined the most (21mm). Seasonal differences also exist in individual regions. The decline of precipitation in southern section of northeast region was mainly occurred in summer, while the decrease of precipitation in northwest region was mainly resulted from the decrease of spring precipitation. As for the increase of precipitation in northern section of northeast region, spring precipitation contributed the most.

  1. Temperatures in Excess of Critical Thresholds Threaten Nestling Growth and Survival in A Rapidly-Warming Arid Savanna: A Study of Common Fiscals

    PubMed Central

    Cunningham, Susan J.; Martin, Rowan O.; Hojem, Carryn L.

    2013-01-01

    Frequency, duration, and intensity of hot-weather events are all predicted to increase with climate warming. Despite this, mechanisms by which temperature increases affect individual fitness and drive population-level changes are poorly understood. We investigated the link between daily maximum air temperature (tmax) and breeding success of Kalahari common fiscals (Lanius collaris) in terms of the daily effect on nestling body-mass gain, and the cumulative effect on size and age of fledglings. High tmax reduced mass gain of younger, but not older nestlings and average nestling-period tmax did not affect fledgling size. Instead, the frequency with which tmax exceeded critical thresholds (tcrits) significantly reduced fledging body mass (tcrit = 33°C) and tarsus length (tcrit = 37°C), as well as delaying fledging (tcrit = 35°C). Nest failure risk was 4.2% per day therefore delays reduced fledging probability. Smaller size at fledging often correlates with reduced lifetime fitness and might also underlie documented adult body-size reductions in desert birds in relation to climate warming. Temperature thresholds above which organisms incur fitness costs are probably common, as physiological responses to temperature are non-linear. Understanding the shape of the relationship between temperature and fitness has implications for our ability to predict species’ responses to climate change. PMID:24040296

  2. Air Mass Origin in the Arctic and its Response to Future Warming

    NASA Technical Reports Server (NTRS)

    Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

    2014-01-01

    We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

  3. WARM AND FUZZY: TEMPERATURE AND DENSITY ANALYSIS OF AN Fe XV EUV IMAGING SPECTROMETER LOOP

    SciTech Connect

    Schmelz, J. T.; Rightmire, L. A.; Kimble, J. A.; Worley, B. T.; Pathak, S.; Saar, S. H.

    2011-09-10

    The Hinode EUV Imaging Spectrometer (EIS) and X-Ray Telescope (XRT) were designed in part to work together. They have the same spatial resolution and cover different but overlapping coronal temperature ranges. These properties make a combined data set ideal for multithermal analysis, where EIS provides the best information on the cooler corona (log T < 6.5) and XRT provides the best information on the hotter corona (log T > 6.5). Here, we analyze a warm non-flaring loop detected in images made in a strong EIS Fe XV emission line with a wavelength of 284.16 A and peak formation temperature of log T = 6.3. We perform differential emission measure (DEM) analysis in three pixels at different heights above the footpoint and find multithermal results with the bulk of the emission measure in the range 6.0 < log T < 6.6. Analysis with the EIS lines alone gave a DEM with huge amounts of emission measure at very high temperatures (log T >7.2); analysis with XRT data alone resulted in a DEM that was missing most of the cooler emission measure required to produce many of the EIS lines. Thus, both results were misleading and unphysical. It was only by combining the EIS and XRT data that we were able to produce a reasonable result, one without ad hoc assumptions on the shape and range of the DEM itself.

  4. Reevaluation of conflicting Eocene tropical temperature estimates: Molluskan oxygen isotope evidence for warm low latitudes

    NASA Astrophysics Data System (ADS)

    Kobashi, Takuro; Grossman, Ethan L.; Yancey, Thomas E.; Dockery, David T., III

    2001-11-01

    Oxygen isotope data from planktonic foraminifera for the warm Eocene epoch suggest that tropical sea-surface temperatures (SSTs) may have been cooler than at present. Such data have stimulated various explanations involving, e.g., major changes in ocean heat transport. However, the planktonic data disagree with terrestrial climate proxies, which suggest significantly warmer low-latitude temperatures. We examined this discrepancy by analyzing seasonal oxygen isotope variations in shallow-marine mollusks from the Mississippi Embayment. Results indicate that mean annual SSTs decreased from 26 27 °C in the early Eocene to 22 23 °C in the Oligocene, agreeing well with temperatures inferred from terrestrial climate proxies. These cooling trends, with more significant winter cooling (5 °C) than summer cooling (3 °C), are consistent with the predicted consequences of decreasing atmospheric CO2 concentration through the Paleogene, suggesting that atmospheric CO2 change was a major controlling factor for Paleogene climate change. That winter SST estimates from the mollusks agree well with the foraminiferal SST estimates suggests that planktonic foraminiferal growth in low latitudes occurred mainly during the cooler winter months throughout the Eocene. We hypothesize that the unusual hydrography of Eocene oceans shifted foraminiferal productivity primarily to winter, biasing foraminiferal SST estimates of mean annual SSTs.

  5. Climate warming revealed by englacial temperatures at Col du Dôme (4250 m, Mont Blanc area)

    NASA Astrophysics Data System (ADS)

    Vincent, Christian; Le Meur, Emmanuel; Six, Delphine; Possenti, Philippe; Lefebvre, Eric; Funk, Martin

    2007-08-01

    Temperatures were measured in two deep boreholes drilled at the same location in the ice at Col du Dôme (4250 m) in 1994 and 2005, providing clear evidence of atmospheric warming. The 1994 temperature profile was already far from steady state conditions. Results from a heat transfer model reveal that the englacial temperature increase cannot be explained solely by atmospheric temperature rise. The latent heat produced by the refreezing of surface meltwater below the surface also contributes to the englacial temperature increase. Although surface melting is normally very low at this altitude, this contribution became significant after 1980 for temperatures at the top of the borehole. Simulations for different climatic scenarios show that glaciated areas located between 3500 and 4250 m could become temperate in the future. This warming could have a major impact on the stability of hanging glaciers frozen to their beds if the melting point is reached.

  6. Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming

    PubMed Central

    Lin, Yong; Franzke, Christian L. E.

    2015-01-01

    Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary. PMID:26259555

  7. Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming

    NASA Astrophysics Data System (ADS)

    Lin, Yong; Franzke, Christian L. E.

    2015-08-01

    Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary.

  8. Lessons Learned from AIRS: Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2011-01-01

    This slide presentation reviews the use of shortwave channels available to the Atmospheric Infrared Sounder (AIRS) to improve the determination of surface and atmospheric temperatures. The AIRS instrument is compared with the Infrared Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A satellite. The objectives of the AIRS/AMSU were to (1) provide real time observations to improve numerical weather prediction via data assimilation, (2) Provide observations to measure and explain interannual variability and trends and (3) Use of AIRS product error estimates allows for QC optimized for each application. Successive versions in the AIRS retrieval methodology have shown significant improvement.

  9. Spatial distribution of air temperature in Toruń (Central Poland) and its causes

    NASA Astrophysics Data System (ADS)

    Przybylak, Rajmund; Uscka-Kowalkowska, Joanna; Araźny, Andrzej; Kejna, Marek; Kunz, Mieczysław; Maszewski, Rafał

    2015-09-01

    In this article, the results of an investigation into the air temperature pattern and development (including the urban heat island (UHI)) in Toruń (central Poland) are presented. For the analysis, daily mean temperature (Ti) as well as daily maximum (Tmax) and minimum (Tmin) temperatures for 2012 gathered for 20 sites, evenly distributed in the area of city, have been taken as source data. Additionally, in order to provide more extensive characteristics of the diversity of the air temperature in the study area, the diurnal temperature range (DTR) and the number of the so-called characteristic days were calculated as well. The impact of weather conditions (cloudiness and wind speed), atmospheric circulation, urban morphological parameters and land cover on the UHI in the study area was investigated. In Toruń, according to the present study, the average UHI intensity in 2012 was equal to 1.0 °C. The rise of cloudiness and wind speed led to a decrease of the magnitude of the UHI. Generally, in most cases, anticyclonic situations favour increased thermal contrast between rural and city areas, particularly in summer. Warm western circulation types significantly reduced temperature differences in the western side of the city and enlarged them in the eastern side of the city. Eastern cold types also have a similar influence on air temperature differences. Positive and statistically significant correlations have been found between the percentage of built-up areas (sealing factor) and air temperature. Conversely, sky view factor (SVF) reveals negative correlations which are statistically significant only for Tmin.

  10. The Benefits of Using Dense Temperature Sensor Networks to Monitor Urban Warming

    NASA Astrophysics Data System (ADS)

    Twine, T. E.; Snyder, P. K.; Kucharik, C. J.; Schatz, J.

    2015-12-01

    Urban heat islands (UHIs) occur when urban and suburban areas experience temperatures that are elevated relative to their rural surroundings because of differences in the fraction of gray and green infrastructure. Studies have shown that communities most at risk for impacts from climate-related disasters (i.e., lower median incomes, higher poverty, lower education, and minorities) tend to live in the hottest areas of cities. Development of adequate climate adaptation tools for cities relies on knowledge of how temperature varies across space and time. Traditionally, a city's urban heat island has been quantified using near-surface air temperature measurements from a few sites. This methodology assumes (1) that the UHI can be characterized by the difference in air temperature from a small number of points, and (2) that these few points represent the urban and rural signatures of the region. This methodology ignores the rich information that could be gained from measurements across the urban to rural transect. This transect could traverse elevations, water bodies, vegetation fraction, and other land surface properties. Two temperature sensor networks were designed and implemented in the Minneapolis-Saint Paul, MN and Madison, WI metropolitan areas beginning in 2011 and 2012, respectively. Both networks use the same model sensor and record temperature every 15 minutes from ~150 sensors. Data from each network has produced new knowledge of how temperature varies diurnally and seasonally across the cities and how the UHI magnitude is influenced by weather phenomena (e.g., wind, snow cover, heat waves) and land surface characteristics such as proximity to inland lakes. However, the two metropolitan areas differ in size, population, structure, and orientation to water bodies. In addition, the sensor networks were established in very different manners. We describe these differences and present lessons learned from the design and ongoing efforts of these two dense networks

  11. Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L

    1952-01-01

    Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

  12. Importance of finite-temperature exchange correlation for warm dense matter calculations

    NASA Astrophysics Data System (ADS)

    Karasiev, Valentin V.; Calderín, Lázaro; Trickey, S. B.

    2016-06-01

    The effects of an explicit temperature dependence in the exchange correlation (XC) free-energy functional upon calculated properties of matter in the warm dense regime are investigated. The comparison is between the Karasiev-Sjostrom-Dufty-Trickey (KSDT) finite-temperature local-density approximation (TLDA) XC functional [Karasiev et al., Phys. Rev. Lett. 112, 076403 (2014), 10.1103/PhysRevLett.112.076403] parametrized from restricted path-integral Monte Carlo data on the homogeneous electron gas (HEG) and the conventional Monte Carlo parametrization ground-state LDA XC [Perdew-Zunger (PZ)] functional evaluated with T -dependent densities. Both Kohn-Sham (KS) and orbital-free density-functional theories are used, depending upon computational resource demands. Compared to the PZ functional, the KSDT functional generally lowers the dc electrical conductivity of low-density Al, yielding improved agreement with experiment. The greatest lowering is about 15% for T =15 kK. Correspondingly, the KS band structure of low-density fcc Al from the KSDT functional exhibits a clear increase in interband separation above the Fermi level compared to the PZ bands. In some density-temperature regimes, the deuterium equations of state obtained from the two XC functionals exhibit pressure differences as large as 4% and a 6% range of differences. However, the hydrogen principal Hugoniot is insensitive to the explicit XC T dependence because of cancellation between the energy and pressure-volume work difference terms in the Rankine-Hugoniot equation. Finally, the temperature at which the HEG becomes unstable is T ≥7200 K for the T -dependent XC, a result that the ground-state XC underestimates by about 1000 K.

  13. Importance of finite-temperature exchange correlation for warm dense matter calculations.

    PubMed

    Karasiev, Valentin V; Calderín, Lázaro; Trickey, S B

    2016-06-01

    The effects of an explicit temperature dependence in the exchange correlation (XC) free-energy functional upon calculated properties of matter in the warm dense regime are investigated. The comparison is between the Karasiev-Sjostrom-Dufty-Trickey (KSDT) finite-temperature local-density approximation (TLDA) XC functional [Karasiev et al., Phys. Rev. Lett. 112, 076403 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.076403] parametrized from restricted path-integral Monte Carlo data on the homogeneous electron gas (HEG) and the conventional Monte Carlo parametrization ground-state LDA XC [Perdew-Zunger (PZ)] functional evaluated with T-dependent densities. Both Kohn-Sham (KS) and orbital-free density-functional theories are used, depending upon computational resource demands. Compared to the PZ functional, the KSDT functional generally lowers the dc electrical conductivity of low-density Al, yielding improved agreement with experiment. The greatest lowering is about 15% for T=15 kK. Correspondingly, the KS band structure of low-density fcc Al from the KSDT functional exhibits a clear increase in interband separation above the Fermi level compared to the PZ bands. In some density-temperature regimes, the deuterium equations of state obtained from the two XC functionals exhibit pressure differences as large as 4% and a 6% range of differences. However, the hydrogen principal Hugoniot is insensitive to the explicit XC T dependence because of cancellation between the energy and pressure-volume work difference terms in the Rankine-Hugoniot equation. Finally, the temperature at which the HEG becomes unstable is T≥7200 K for the T-dependent XC, a result that the ground-state XC underestimates by about 1000 K. PMID:27415377

  14. Transitional properties of supersolitons in a two electron temperature warm multi-ion plasma

    NASA Astrophysics Data System (ADS)

    Varghese, Steffy S.; Ghosh, S. S.

    2016-08-01

    The existence domain of an ion acoustic supersoliton and its transition to a regular kind of solitary wave have been explored in detail using Sagdeev pseudopotential technique for a two electron temperature warm multi-ion plasma having two species of ions. It was found that both the cold to hot electron temperature ratio and their respective ambient densities play a deterministic role for the existence of a supersoliton, as well as its transitional processes to a regular solitary wave. Analogous to a double layer solution, which often marks the boundary of the existence domain of a regular solitary wave, a "curve of inflection" determines the boundary of the existence domain of a supersoliton. The characteristics of the "curve of inflection," in turn, depend on the respective concentrations of the two ion species. It is observed that the supersolitons are actually a subset of a more general kind of solutions which are characterized by a fluctuation in the corresponding charge separation which precedes their maximum amplitude. It is also observed that these novel kinds of solitary structures, including supersolitons, occur only for a very narrow range of parameters near constant amplitude beyond which the wave breaks.

  15. A physically based analytical spatial air temperature and humidity model

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Endreny, Theodore A.; Nowak, David J.

    2013-09-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

  16. Xylem anatomical responses of Vaccinium myrtillus exposed to air CO2 enrichment and soil warming at treeline

    NASA Astrophysics Data System (ADS)

    Anadon-Rosell, Alba; Fonti, Patrick; Dawes, Melissa; von Arx, Georg

    2016-04-01

    Plant life at treeline is limited by harsh growth conditions. In this study we used nine years of free air CO2 enrichment (+200 ppm from 2001 to 2009) and six years of soil warming (+4 °C from 2007 to 2012) at a treeline experimental site in the Swiss Alps to investigate xylem anatomical responses of Vaccinium myrtillus, a co-dominant dwarf shrub in many treeline communities. Our aim was to identify whether the release from limiting growth conditions induced adjustments of the water conductive and storage tissues. High-resolution images of wood anatomical microsections from the stem base of 40 individuals were captured with a digital camera mounted on a microscope. We used the specialized image analysis tool ROXAS to quantify size, density, grouping patterns, and potential hydraulic conductivity of vessels. In addition, we measured the abundance and distribution of ray parenchyma. Our preliminary results show that CO2 enrichment and soil warming induced contrasting anatomical responses. In the last years of the CO2 enhancement vessels were larger, whereas soil warming induced an immediate reduction of vessel size. Moreover, larger vessels were found when V. myrtillus was in cohabitation with pine as opposed to larch. Results for ray parenchyma measurements did not show clear trends, although warming seemed to have a slightly positive effect on the fraction of uniseriate vs. multiseriate rays. These results suggest that release from the growth limiting factors can result in contrasting and partially lagged responses in the hydraulic system with little impact on the storage tissues. In addition, the overstory species seem to play a key role on the anatomy of V. myrtillus at treeline.

  17. Unprecedented recent warming rate and temperature variability over the east Tibetan Plateau inferred from Alpine treeline dendrochronology

    NASA Astrophysics Data System (ADS)

    Shi, Chunming; Masson-Delmotte, Valérie; Daux, Valérie; Li, Zongshan; Carré, Matthieu; Moore, John C.

    2015-09-01

    Despite instrumental records showing recent large temperature rises on the Tibetan Plateau (TP), only a few tree-ring temperature reconstructions do capture this warming trend. Here, we sampled 260 trees from seven Alpine treeline locations across the southeast TP. Standardized tree-ring width chronologies of Abies squamata and Sabina squamat were produced following Regional Curve Standardization detrending. The leading principal component of these records is well correlated with the regional summer (JJA) minimum temperature (MinT) (R2 = 0.47, P < 0.001, 1953-2009). Hence we produce a regional summer MinT reconstruction spanning the last 212 years. This reconstruction reveals a long-term persistent warming trend, starting in the 1820s, at a rate of 0.45 ± 0.09 °C/century (1820-2009). This trend is also detected since the 1820s in the Asian summer MinT reconstruction produced by the PAGES 2K project, with a very close warming rate (0.43 ± 0.08 °C/century, 1820-1989). Our record also displays an enhanced multi-decadal variability since the mid-twentieth century. The 1990s-2000s are the warmest of our whole record, due to the superposition of the gradual warming trend and decadal variability during this interval. The strongest decadal cooling occurs during the 1950s and the largest warming trend during the 1970s. The magnitude of warming from 1973 to 2003 was larger than the total warming trend from 1820s to 2009. Extreme events are also more frequent since 1950. The pattern of multi-decadal variability has similarities with the Atlantic multi-decadal oscillation, suggesting common causality. CMIP5 historical simulations fail to capture both the magnitude and timing of this multi-decadal variability. The ensemble CMIP5 average produces a steady warming trend starting in the 1970s, which only accounts for about 60 % of the observed warming trend during this period. We conclude that TP summer temperature could reflect a climate response to increased greenhouse gas

  18. Traceability and reliable uncertainty calculation of near-surface air temperature measurements.

    NASA Astrophysics Data System (ADS)

    Izquierdo, C. G.; Merlone, A.

    2014-12-01

    Near-surface air temperature is one of the Essential Climate Variables defined by GCOS (Global Climate Observing System) and currently, it is the most important variable in the climatic analysis of global warming. A reliable affirmation of climate change or global warming must be based on reliable measurements which imply traceability of such measurements and a consistent uncertainty calculation. The improvement of these two aspects is covered by the European projects MeteoMet1 and its successor, MeteoMet2, within the frame of the European Metrology Research Program (EMRP). These two projects count on the participation of several European metrology and meteorology national institutes together with universities and manufacturers. They are focused on responding to the need for new stable and comparable measurement standards, protocols, sensors and calibration procedures, data-fusion and uncertainty evaluation methods, to enhance data reliability and to reduce uncertainties in climate models. This presentation describes the activities related with air temperature measurements included in both projects and the scientific achievements reached in MeteoMet1 project

  19. Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from forest fires

    NASA Astrophysics Data System (ADS)

    Rosenfeld, Daniel; Yu, Xing; Liu, Guihua; Xu, Xiaohong; Zhu, Yannian; Yue, Zhiguo; Dai, Jin; Dong, Zipeng; Dong, Yan; Peng, Yan

    2011-11-01

    Heavy aerosol loads have been observed to suppress warm rain by reducing cloud drop size and slowing drop coalescence. The ice forming nuclei (IFN) activity of the same aerosols glaciate the clouds and create ice precipitation instead of the suppressed warm rain. Satellite observations show that desert dust and heavy air pollution over East Asia have similar ability to glaciate the tops of growing convective clouds at glaciation temperature of Tg < ˜ -20°C, whereas similarly heavy smoke from forest fires in Siberia without dust or industrial pollution glaciated clouds at Tg ≤ -33°C. The observation that both smoke and air pollution have same effect on reducing cloud drop size implies that the difference in Tg is due to the IFN activity. This dependence of Tg on aerosol types appears only for clouds with re-5 < 12 μm (re-5 is the cloud drop effective radius at the -5°C isotherm, above which ice rarely forms in cloud tops). For the rest of the clouds the glaciation temperature increases strongly with re-5 with little relation to the aerosol types, reaching Tg> ˜ -15°C for the largest re-5, which are typical to marine clouds in pristine atmosphere.

  20. Equipment for Measuring Air Flow, Air Temperature, Relative Humidity, and Carbon Dioxide in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Jacobs, Bruce W.

    Information on equipment and techniques that school facility personnel may use to evaluate IAQ conditions are discussed. Focus is placed on the IAQ parameters of air flow, air temperature, relative humidity, as well as carbon dioxide and the equipment used to measure these factors. Reasons for measurement and for when the measurement of these…

  1. Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best

  2. Sampling Biases in Datasets of Historical Mean Air Temperature over Land

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun

    2014-04-01

    Global mean surface air temperature (Ta) has been reported to have risen by 0.74°C over the last 100 years. However, the definition of mean Ta is still a subject of debate. The most defensible definition might be the integral of the continuous temperature measurements over a day (Td0). However, for technological and historical reasons, mean Ta over land have been taken to be the average of the daily maximum and minimum temperature measurements (Td1). All existing principal global temperature analyses over land rely heavily on Td1. Here, I make a first quantitative assessment of the bias in the use of Td1 to estimate trends of mean Ta using hourly Ta observations at 5600 globally distributed weather stations from the 1970s to 2013. I find that the use of Td1 has a negligible impact on the global mean warming rate. However, the trend of Td1 has a substantial bias at regional and local scales, with a root mean square error of over 25% at 5° × 5° grids. Therefore, caution should be taken when using mean Ta datasets based on Td1 to examine high resolution details of warming trends.

  3. Sampling biases in datasets of historical mean air temperature over land.

    PubMed

    Wang, Kaicun

    2014-01-01

    Global mean surface air temperature (Ta) has been reported to have risen by 0.74°C over the last 100 years. However, the definition of mean Ta is still a subject of debate. The most defensible definition might be the integral of the continuous temperature measurements over a day (Td0). However, for technological and historical reasons, mean Ta over land have been taken to be the average of the daily maximum and minimum temperature measurements (Td1). All existing principal global temperature analyses over land rely heavily on Td1. Here, I make a first quantitative assessment of the bias in the use of Td1 to estimate trends of mean Ta using hourly Ta observations at 5600 globally distributed weather stations from the 1970s to 2013. I find that the use of Td1 has a negligible impact on the global mean warming rate. However, the trend of Td1 has a substantial bias at regional and local scales, with a root mean square error of over 25% at 5° × 5° grids. Therefore, caution should be taken when using mean Ta datasets based on Td1 to examine high resolution details of warming trends. PMID:24717688

  4. Variation in summer surface air temperature over Northeast Asia and its associated circulation anomalies

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Hong, Xiaowei; Lu, Riyu; Jin, Aifen; Jin, Shizhu; Nam, Jae-Cheol; Shin, Jin-Ho; Goo, Tae-Young; Kim, Baek-Jo

    2016-01-01

    This study investigates the interannual variation of summer surface air temperature over Northeast Asia (NEA) and its associated circulation anomalies. Two leading modes for the temperature variability over NEA are obtained by EOF analysis. The first EOF mode is characterized by a homogeneous temperature anomaly over NEA and therefore is called the NEA mode. This anomaly extends from southeast of Lake Baikal to Japan, with a central area in Northeast China. The second EOF mode is characterized by a seesaw pattern, showing a contrasting distribution between East Asia (specifically including the Changbai Mountains in Northeast China, Korea, and Japan) and north of this region. This mode is named the East Asia (EA) mode. Both modes contribute equivalently to the temperature variability in EA. The two leading modes are associated with different circulation anomalies. A warm NEA mode is associated with a positive geopotential height anomaly over NEA and thus a weakened upper-tropospheric westerly jet. On the other hand, a warm EA mode is related to a positive height anomaly over EA and a northward displaced jet. In addition, the NEA mode tends to be related to the Eurasian teleconnection pattern, while the EA mode is associated with the East Asia-Pacific/Pacific-Japan pattern.

  5. Estimation of sampling error uncertainties in observed surface air temperature change in China

    NASA Astrophysics Data System (ADS)

    Hua, Wei; Shen, Samuel S. P.; Weithmann, Alexander; Wang, Huijun

    2016-06-01

    This study examines the sampling error uncertainties in the monthly surface air temperature (SAT) change in China over recent decades, focusing on the uncertainties of gridded data, national averages, and linear trends. Results indicate that large sampling error variances appear at the station-sparse area of northern and western China with the maximum value exceeding 2.0 K2 while small sampling error variances are found at the station-dense area of southern and eastern China with most grid values being less than 0.05 K2. In general, the negative temperature existed in each month prior to the 1980s, and a warming in temperature began thereafter, which accelerated in the early and mid-1990s. The increasing trend in the SAT series was observed for each month of the year with the largest temperature increase and highest uncertainty of 0.51 ± 0.29 K (10 year)-1 occurring in February and the weakest trend and smallest uncertainty of 0.13 ± 0.07 K (10 year)-1 in August. The sampling error uncertainties in the national average annual mean SAT series are not sufficiently large to alter the conclusion of the persistent warming in China. In addition, the sampling error uncertainties in the SAT series show a clear variation compared with other uncertainty estimation methods, which is a plausible reason for the inconsistent variations between our estimate and other studies during this period.

  6. Effect of low air velocities on thermal homeostasis and comfort during exercise at space station operational temperature and humidity

    NASA Technical Reports Server (NTRS)

    Beumer, Ronald J.

    1989-01-01

    The effectiveness of different low air velocities in maintaining thermal comfort and homeostasis during exercise at space station operational temperature and humidity was investigated. Five male subjects exercised on a treadmill for successive ten minute periods at 60, 71, and 83 percent of maximum oxygen consumption at each of four air velocities, 30, 50, 80, and 120 ft/min, at 22 C and 62 percent relative humidity. No consistent trends or statistically significant differences between air velocities were found in body weight loss, sweat accumulation, or changes in rectal, skin, and body temperatures. Occurrence of the smallest body weight loss at 120 ft/min, the largest sweat accumulation at 30 ft/min, and the smallest rise in rectal temperature and the greatest drop in skin temperature at 120 ft/min all suggested more efficient evaporative cooling at the highest velocity. Heat storage at all velocities was evidenced by increased rectal and body temperatures; skin temperatures declined or increased only slightly. Body and rectal temperature increases corresponded with increased perception of warmth and slight thermal discomfort as exercise progressed. At all air velocities, mean thermal perception never exceeded warm and mean discomfort, greatest at 30 ft/min, was categorized at worst as uncomfortable; sensation of thermal neutrality and comfort returned rapidly after cessation of exercise. Suggestions for further elucidation of the effects of low air velocities on thermal comfort and homeostasis include larger numbers of subjects, more extensive skin temperature measurements and more rigorous analysis of the data from this study.

  7. The influence of air temperature for solvent evaporation on bonding of self-etch adhesives to dentin

    PubMed Central

    Moura, Sandra Kiss; Murad, Cintia Gaio; Reis, Alessandra; Klein-Júnior, Celso Afonso; Grande, Rosa Helena Miranda; Loguercio, Alessandro Dourado

    2014-01-01

    Objective: This study evaluated the effect of air temperature (warm or cold) for solvent evaporation on bonding and nanoleakage of self-etching adhesives to dentin. Materials and Methods: The adhesives Clearfil 3S Bond [S3], OptiBond All-In-One [OB], Adper SE Plus [AD], and Silorane adhesive [SI] were applied on dentin surfaces, and a warm (60 ± 2°C) or cold air (20 ± 1°C) was applied and light-cured. After water storage (24 h), the teeth were sectioned into sticks (0.8 mm2) and tested in tensile. Then, they were immersed in a 50% solution of silver nitrate, photo-developed and the nanoleakage observed in a scanning electron microscope. The bond strength and nanoleakage pattern were analyzed by two-way analysis of variance and post hoc Tukey's test (α =0.05). Results: Higher bond strength and lower silver nitrate uptake were observed for the adhesives under warm condition (P < 0.05). AD and SI showed better adhesive results than S3 and OB (P < 0.05). Conclusion: The use of a warm air was useful to improve the bonding and diminish the nanoleakage of adhesive systems to dentin. PMID:24966771

  8. Warm Root Temperature Mitigates the Effect of Chilling in the Dark on Photosynthesis in Cotton (Gossypium hirsutum) Seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Productivity of warm season crops such as cotton (Gossypium hirsutum L.) can be reduced by untimely episodes of chilling temperature that often occur during the first weeks after planting. We examined the impact of chilling stress on cotton seedlings two weeks after planting by chilling both shoots...

  9. 1200 years of warm-season temperature variability in central Scandinavia inferred from tree-ring density

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Linderholm, Hans W.; Gunnarson, Björn E.; Björklund, Jesper; Chen, Deliang

    2016-06-01

    Despite the emergence of new high-resolution temperature reconstructions around the world, only a few cover the Medieval Climate Anomaly (MCA). Here we present C-Scan, a new Scots pine tree-ring density-based reconstruction of warm-season (April-September) temperatures for central Scandinavia back to 850 CE, extending the previous reconstruction by 250 years. C-Scan is based on samples collected in a confined mountain region, adjusted for their differences in altitude and local environment, and standardised using the new RSFi algorithm to preserve low-frequency signals. In C-Scan, the warm peak of MCA occurs ca. 1000-1100 CE, and the Little Ice Age (LIA) between 1550 and 1900 CE. Moreover, during the last millennium the coldest decades are found around 1600 CE, and the warmest 10 and 30 years occur in the most recent century. By comparing C-Scan with other millennium-long temperature reconstructions from Fennoscandia, regional differences in multi-decadal temperature variability, especially during the warm period of the last millennium are revealed. Although these differences could be due to methodological reasons, they may indicate asynchronous warming patterns across Fennoscandia. Further investigation of these regional differences and the reasons and mechanisms behind them are needed.

  10. Local response to warm Antarctic terrestrial temperatures in the Eocene: evidence from terrestrial biomarkers

    NASA Astrophysics Data System (ADS)

    Toney, J. L.; Bendle, J. A.; Inglis, G.; Bijl, P.; Pross, J.; Contreras, L.; van de Flierdt, T.; Huck, C. E.; Jamieson, S.; Huber, M.; Schouten, S.; Roehl, U.; Bohaty, S. M.; Brinkhuis, H.

    2011-12-01

    calculated from the Eocene runs of the Community Climate System Model version 3 and Antarctic topographic modelling are used to constrain the source region for the warm terrestrial temperatures and soil/wetland inputs.

  11. Climatology of upper air temperature in the Eastern Mediterranean region

    NASA Astrophysics Data System (ADS)

    Philandras, C. M.; Nastos, P. T.; Kapsomenakis, I. N.; Repapis, C. C.

    2015-01-01

    The goal of this study is to contribute to the climatology of upper air temperature in the Mediterranean region, during the period 1965-2011. For this purpose, both radiosonde recordings and gridded reanalysis datasets of upper air temperature from National Center for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) were used for seven barometric levels at 850 hPa, 700 hPa, 500 hPa, 300 hPa, 200 hPa, 150 hPa and 100 hPa. Trends and variability of upper air temperature were analyzed on annual and seasonal basis. Further, the impact of atmospheric circulation, by means of correlation between upper air temperature at different barometric levels and specific climatic indices such as Mediterranean Oscillation Index (MOI), North Sea Caspian Pattern Index (NCPI) and North Atlantic Oscillation Index (NAOI), was also quantified. Our findings have given evidence that air temperature is increasing at a higher rate in lower/middle troposphere against upper, and this is very likely due to increasing greenhouse gas concentrations.

  12. Long range global warming

    SciTech Connect

    Rolle, K.C.; Pulkrabek, W.W.; Fiedler, R.A.

    1995-12-31

    This paper explores one of the causes of global warming that is often overlooked, the direct heating of the environment by engineering systems. Most research and studies of global warming concentrate on the modification that is occurring to atmospheric air as a result of pollution gases being added by various systems; i.e., refrigerants, nitrogen oxides, ozone, hydrocarbons, halon, and others. This modification affects the thermal radiation balance between earth, sun and space, resulting in a decrease of radiation outflow and a slow rise in the earth`s steady state temperature. For this reason the solution to the problem is perceived as one of cleaning up the processes and effluents that are discharged into the environment. In this paper arguments are presented that suggest, that there is a far more serious cause for global warming that will manifest itself in the next two or three centuries; direct heating from the exponential growth of energy usage by humankind. Because this is a minor contributor to the global warming problem at present, it is overlooked or ignored. Energy use from the combustion of fuels and from the output of nuclear reactions eventually is manifest as warming of the surroundings. Thus, as energy is used at an ever increasing rate the consequent global warming also increases at an ever increasing rate. Eventually this rate will become equal to a few percent of solar radiation. When this happens the earth`s temperature will have risen by several degrees with catastrophic results. The trends in world energy use are reviewed and some mathematical models are presented to suggest future scenarios. These models can be used to predict when the global warming problem will become undeniably apparent, when it will become critical, and when it will become catastrophic.

  13. Recent changes in air temperature, heat waves occurrences, and atmospheric circulation in Northern Africa

    NASA Astrophysics Data System (ADS)

    Fontaine, Bernard; Janicot, Serge; Monerie, Paul-Arthur

    2013-08-01

    study documents the time evolution of air temperature and heat waves occurrences over Northern Africa for the period 1979-2011. A significant warming (1°-3°C), appearing by the mid-1960s over Sahara and Sahel, is associated with higher/lesser frequency of warm/cold temperatures, as with longer duration and higher occurrences of heat waves. Heat waves episodes of at least 4 day duration have been examined after removing the long-term evolution. These episodes are associated with specific anomalies: (i) in spring, positive low-level temperature anomalies over the Sahel and Sahara; low and midlevel cyclonic rotation over Morocco associated with a Rossby wave pattern, lessening the Harmattan; more/less atmospheric moisture westward/eastward to 0°; upward/downward anomalies above the western/eastern regions associated with the Rossby wave pattern; (ii) in summer, a similar but weaker positive low-level temperature anomaly (up to 3°C); less moisture westward to 10°W, a cyclonic anomaly in central Sahel favoring the monsoon eastward to 0° and a midlevel anticyclonic anomaly over the Western Sahara, increasing southward the flux divergence associated with the African Easterly Jet. In March-May, two to three heat waves propagate eastward. They are preceded by an abnormal warm cell over Libya and southwesterlies over the West Sahara. A large trough stands over North Atlantic while midtropospheric subsidence and anticyclonic rotation reinforce over the continent, then migrates toward the Arabian peninsula in breaking up. These signals are spatially coherent and might suggest the role of short Rossby waves with an eastward group velocity and a baroclinic mode, possibly associated with jet stream deformation.

  14. Heat tolerance of higher plants cenosis to damaging air temperatures

    NASA Astrophysics Data System (ADS)

    Ushakova, Sofya; Shklavtsova, Ekaterina

    Designing sustained biological-technical life support systems (BTLSS) including higher plants as a part of a photosynthesizing unit, it is important to foresee the multi species cenosis reaction on either stress-factors. Air temperature changing in BTLSS (because of failure of a thermoregulation system) up to the values leading to irreversible damages of photosynthetic processes is one of those factors. However, it is possible to increase, within the certain limits, the plant cenosis tolerance to the unfavorable temperatures’ effect due to the choice of the higher plants possessing resistance both to elevated and to lowered air temperatures. Besides, the plants heat tolerance can be increased when subjecting them during their growing to the hardening off temperatures’ effect. Thus, we have come to the conclusion that it is possible to increase heat tolerance of multi species cenosis under the damaging effect of air temperature of 45 (°) СC.

  15. Innovative coal gasification system with high temperature air

    SciTech Connect

    Yoshikawa, K.; Katsushima, H.; Kasahara, M.; Hasegawa, T.; Tanaka, R.; Ootsuka, T.

    1997-12-31

    This paper proposes innovative coal gasification power generation systems where coal is gasified with high temperature air of about 1300K produced by gasified coal fuel gas. The main features of these systems are high thermal efficiency, low NO{sub x} emission, compact desulfurization and dust removal equipment and high efficiency molten slag removal with a very compact gasifier. Recent experimental results on the pebble bed coal gasifier appropriate for high temperature air coal gasification are reported, where 97.7% of coal ash is successfully caught in the pebble bed and extracted without clogging. A new concept of high temperature air preheating system is proposed which is characterized by its high reliability and low cost.

  16. The role of subsurface soil temperature feedbacks in summer surface air temperature variability over East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2012-12-01

    Soil temperature, an important component of land surface, can influence the climate through its effects on surface energy and water budgets and resulted changes in regional atmospheric circulation. However, the effects of soil temperature on climate variations have been less discussed. This study investigates the role of subsurface soil temperature feedbacks in influencing summer surface air temperature variability over East Asia by means of regional climate model (RCM) simulations. For this aim, two long-term simulations with and without subsurface soil temperature feedbacks are performed with the Weather Research and Forecasting (WRF) model. From our investigation, it is evident that subsurface soil temperature feedbacks make a dominant contribution to amplifying summer surface air temperature variability over the arid/semi-arid regions. Further analysis reveals that subsurface soil temperature exhibits an asymmetric effect on summer daytime and nighttime surface air temperature variability, with a stronger effect on daily minimum temperature variability than that of daily maximum temperature variability. This study provides the first RCM-based demonstration that subsurface soil temperature feedbacks play an important role in influencing climate variability over East Asia, such as summer surface air temperature. In the meanwhile, the model bias should be recognized. The results achieved by this study thus need to be further confirmed in a multi-model framework to eliminate the model dependence.

  17. Passive radiative cooling below ambient air temperature under direct sunlight.

    PubMed

    Raman, Aaswath P; Anoma, Marc Abou; Zhu, Linxiao; Rephaeli, Eden; Fan, Shanhui

    2014-11-27

    Cooling is a significant end-use of energy globally and a major driver of peak electricity demand. Air conditioning, for example, accounts for nearly fifteen per cent of the primary energy used by buildings in the United States. A passive cooling strategy that cools without any electricity input could therefore have a significant impact on global energy consumption. To achieve cooling one needs to be able to reach and maintain a temperature below that of the ambient air. At night, passive cooling below ambient air temperature has been demonstrated using a technique known as radiative cooling, in which a device exposed to the sky is used to radiate heat to outer space through a transparency window in the atmosphere between 8 and 13 micrometres. Peak cooling demand, however, occurs during the daytime. Daytime radiative cooling to a temperature below ambient of a surface under direct sunlight has not been achieved because sky access during the day results in heating of the radiative cooler by the Sun. Here, we experimentally demonstrate radiative cooling to nearly 5 degrees Celsius below the ambient air temperature under direct sunlight. Using a thermal photonic approach, we introduce an integrated photonic solar reflector and thermal emitter consisting of seven layers of HfO2 and SiO2 that reflects 97 per cent of incident sunlight while emitting strongly and selectively in the atmospheric transparency window. When exposed to direct sunlight exceeding 850 watts per square metre on a rooftop, the photonic radiative cooler cools to 4.9 degrees Celsius below ambient air temperature, and has a cooling power of 40.1 watts per square metre at ambient air temperature. These results demonstrate that a tailored, photonic approach can fundamentally enable new technological possibilities for energy efficiency. Further, the cold darkness of the Universe can be used as a renewable thermodynamic resource, even during the hottest hours of the day. PMID:25428501

  18. Interannual and interdecadal variability in United States surface-air temperatures, 1910-87

    USGS Publications Warehouse

    Dettinger, M.D.; Ghil, M.; Keppenne, C.L.

    1995-01-01

    Monthly mean surface-air temperatures at 870 sites in the contiguous United States were analyzed for interannual and interdecadal variability over the time interval 1910-87. The temperatures were analyzed spatially by empirical-orthogonal-function analysis and temporally by singularspectrum analysis (SSA). The dominant modes of spatio-temporal variability are trends and nonperiodic variations with time scales longer than 15 years, decadal-scale oscillations with periods of roughly 7 and 10 years, and interannual oscillations of 2.2 and 3.3 years. Together, these modes contribute about 18% of the slower-than-annual United States temperature variance. Two leading components roughly capture the mean hemispheric temperature trend and represent a long-term warming, largest in the southwest, accompanied by cooling of the domain's southeastern quadrant. The extremes of the 2.2-year interannual oscillation characterize temperature differences between the Northeastern and Southwestern States, whereas the 3.3-year cycle is present mostly in the Western States. The 7- to 10-year oscillations are much less regular and persistent than the interannual oscillations and characterize temperature differences between the western and interior sectors of the United States. These continental- or regional-scale temperature variations may be related to climatic variations with similar periodicities, either global or centered in other regions; such variations include quasi-biennial oscillations over the tropical Pacific or North Atlantic and quasi-triennial oscillations of North Pacific sea-surface temperatures.

  19. Emission Controls Using Different Temperatures of Combustion Air

    PubMed Central

    Holubčík, Michal; Papučík, Štefan

    2014-01-01

    The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

  20. The Veriability of Radiative Balance Elements and Air Temperature on the Asian Region of Russia

    NASA Astrophysics Data System (ADS)

    Kharyutkina, E. V.; Ippolitov, I. I.; Loginov, S. V.

    2011-01-01

    The variability of spatial-temporal distribution of temperature and radiative and heat balances components is investigated for the Asian territory of Russia (45 - 80oN, 60-180oE) using JRA-25 reanalysis data for the period of current global warming 1979-2008 It is shown that since the beginning of 90th of XX century the increase of back earth-atmosphere short-wave radiation is observed. Such tendency is in conformity with the cloud cover dynamics and downward short-wave radiation at the surface. Annual averaged radiative balance values at the top are negative; it is consistent with negative annual averaged air temperature, averaged over territory. The downward trend of radiative balance is the most obvious after the beginning of 90th of XX century.

  1. The design of an air-cooled metallic high temperature radial turbine

    NASA Technical Reports Server (NTRS)

    Snyder, Philip H.; Roelke, Richard J.

    1988-01-01

    Recent trends in small advanced gas turbine engines call for higher turbine inlet temperatures. Advances in radial turbine technology have opened the way for a cooled metallic radial turbine capable of withstanding turbine inlet temperatures of 2500 F while meeting the challenge of high efficiency in this small flow size range. In response to this need, a small air-cooled radial turbine has been designed utilizing internal blade coolant passages. The coolant flow passage design is uniquely tailored to simultaneously meet rotor cooling needs and rotor fabrication constraints. The rotor flow-path design seeks to realize improved aerodynamic blade loading characteristics and high efficiency while satisfying rotor life requirements. An up-scaled version of the final engine rotor is currently under fabrication and, after instrumentation, will be tested in the warm turbine test facility at the NASA Lewis Research Center.

  2. A hierarchical model of daily stream temperature using air-water temperature synchronization, autocorrelation, and time lags

    USGS Publications Warehouse

    Letcher, Benjamin; Hocking, Daniel; O'Neill, K.; Whiteley, Andrew R.; Nislow, Keith H.; O'Donnell, Matthew

    2016-01-01

    Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make stream temperature estimation difficult. Our model identifies the yearly period when air and water temperature are synchronized, accommodates hysteresis, incorporates time lags, deals with missing data and autocorrelation and can include external drivers. In a small stream network, the model performed well (RMSE = 0.59 °C), identified a clear warming trend (0.63 °C · decade-1) and a widening of the synchronized period (29 d · decade-1). We also carefully evaluated how missing data influenced predictions. Missing data within a year had a small effect on performance (~ 0.05% average drop in RMSE with 10% fewer days with data). Missing all data for a year decreased performance (~ 0.6 °C jump in RMSE), but this decrease was moderated when data were available from other streams in the network.

  3. A hierarchical model of daily stream temperature using air-water temperature synchronization, autocorrelation, and time lags.

    PubMed

    Letcher, Benjamin H; Hocking, Daniel J; O'Neil, Kyle; Whiteley, Andrew R; Nislow, Keith H; O'Donnell, Matthew J

    2016-01-01

    Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make stream temperature estimation difficult. Our model identifies the yearly period when air and water temperature are synchronized, accommodates hysteresis, incorporates time lags, deals with missing data and autocorrelation and can include external drivers. In a small stream network, the model performed well (RMSE = 0.59°C), identified a clear warming trend (0.63 °C decade(-1)) and a widening of the synchronized period (29 d decade(-1)). We also carefully evaluated how missing data influenced predictions. Missing data within a year had a small effect on performance (∼0.05% average drop in RMSE with 10% fewer days with data). Missing all data for a year decreased performance (∼0.6 °C jump in RMSE), but this decrease was moderated when data were available from other streams in the network. PMID:26966662

  4. A hierarchical model of daily stream temperature using air-water temperature synchronization, autocorrelation, and time lags

    PubMed Central

    Hocking, Daniel J.; O’Neil, Kyle; Whiteley, Andrew R.; Nislow, Keith H.; O’Donnell, Matthew J.

    2016-01-01

    Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make stream temperature estimation difficult. Our model identifies the yearly period when air and water temperature are synchronized, accommodates hysteresis, incorporates time lags, deals with missing data and autocorrelation and can include external drivers. In a small stream network, the model performed well (RMSE = 0.59°C), identified a clear warming trend (0.63 °C decade−1) and a widening of the synchronized period (29 d decade−1). We also carefully evaluated how missing data influenced predictions. Missing data within a year had a small effect on performance (∼0.05% average drop in RMSE with 10% fewer days with data). Missing all data for a year decreased performance (∼0.6 °C jump in RMSE), but this decrease was moderated when data were available from other streams in the network. PMID:26966662

  5. Biochemical acclimation, stomatal limitation and precipitation patterns underlie decreases in photosynthetic stimulation of Soybean (Glycine max) at elevated [CO2] and temperatures under fully open air field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The net effect of elevated [CO2] and temperature on photosynthetic acclimation and plant productivity is poorly resolved. We assessed the effects of canopy warming and fully open air [CO2] enrichment on 1) the acclimation of two biochemical parameters that frequently limit photosynthesis (A), the ma...

  6. Using MODIS land surface temperatures and the Crocus snow model to understand the warm bias of ERA-Interim reanalyses at the surface in Antarctica

    NASA Astrophysics Data System (ADS)

    Fréville, H.; Brun, E.; Picard, G.; Tatarinova, N.; Arnaud, L.; Lanconelli, C.; Reijmer, C.; van den Broeke, M.

    2014-07-01

    Moderate-Resolution Imaging spectroradiometer (MODIS) land surface temperatures in Antarctica were processed in order to produce a gridded data set at 25 km resolution, spanning the period 2000-2011 at an hourly time step. The Aqua and Terra orbits and MODIS swath width, combined with frequent clear-sky conditions, lead to very high availability of quality-controlled observations: on average, hourly data are available 14 h per day at the grid points around the South Pole and more than 9 h over a large area of the Antarctic Plateau. Processed MODIS land surface temperatures, referred to hereinafter as MODIS Ts values, were compared with in situ hourly measurements of surface temperature collected over the entirety of the year 2009 by seven stations from the Baseline Surface Radiation Network (BSRN) and automatic weather stations (AWSs). In spite of an occasional failure in the detection of clouds, MODIS Ts values exhibit a good performance, with a bias ranging from -1.8 to 0.1 °C and errors ranging from 2.2 to 4.8 °C root mean square at the five stations located on the plateau. These results show that MODIS Ts values can be used as a precise and accurate reference to test other surface temperature data sets. Here, we evaluate the performance of surface temperature in the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis known as ERA-Interim reanalysis. During conditions detected as cloud free by MODIS, ERA-Interim shows a widespread warm bias in Antarctica in every season, ranging from +3 to +6 °C on the plateau. This confirms a recent study which showed that the largest discrepancies in 2 m air temperature between ERA-Interim and the global temperature data set HadCRUT4 compiled by the Met Office Hadley Centre and the University of East Anglia's Climatic Research Unit occur in Antarctica. A comparison with in situ surface temperature shows that this bias is not strictly limited to clear-sky conditions. A detailed comparison with stand

  7. Pulsed positive streamer discharges in air at high temperatures

    NASA Astrophysics Data System (ADS)

    Ono, Ryo; Kamakura, Taku

    2016-08-01

    Atmospheric-pressure air pulsed positive streamer discharges are generated in a 13 mm point-plane gap in the temperature range of 293 K–1136 K, and the effect of temperature on the streamer discharges is studied. When the temperature is increased, the product of applied voltage and temperature VT proportional to the reduced electric field can be used as a primary parameter that determines some discharge parameters regardless of temperature. For a given VT, the transferred charge per pulse, streamer diameter, product of discharge energy and temperature, and length of secondary streamer are almost constant regardless of T, whereas the streamer velocity decreases with increasing T and the decay rate of the discharge current is proportional to 1/T. The N2(C) emission intensity is approximately determined by the discharge energy independent of T. These results are useful to predict the streamer discharge and its reactive species production when the ambient temperature is increased.

  8. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  9. Temperature gradients and clear-air turbulence probabilities

    NASA Technical Reports Server (NTRS)

    Bender, M. A.; Panofsky, H. A.; Peslen, C. A.

    1976-01-01

    In order to forecast clear-air turbulence (CAT) in jet aircraft flights, a study was conducted in which the data from a special-purpose instrument aboard a Boeing 747 jet airliner were compared with satellite-derived radiance gradients, conventional temperature gradients from analyzed maps, and temperature gradients obtained from a total air temperature sensor on the plane. The advantage of making use of satellite-derived data is that they are available worldwide without the need for radiosonde observations, which are scarce in many parts of the world. Major conclusions are that CAT probabilities are significantly higher over mountains than flat terrain, and that satellite radiance gradients appear to discriminate between CAT and no CAT better than conventional temperature gradients over flat lands, whereas the reverse is true over mountains, the differences between the two techniques being not large over mountains.

  10. Air-sea temperature decoupling in western Europe during the last interglacial-glacial transition

    NASA Astrophysics Data System (ADS)

    Sánchez Goñi, María Fernanda; Bard, Edouard; Landais, Amaelle; Rossignol, Linda; D'Errico, Francesco

    2013-10-01

    A period of continental ice growth between about 80,000 and 70,000 years ago was controlled by a decrease in summer insolation, and was among the four largest ice expansions of the past 250,000 years. The moisture source for this ice sheet expansion, known as the Marine Isotope Stage (MIS) 5a/4 transition, has been proposed to be the warm subpolar and northern subtropical Atlantic Ocean. However, the mechanism by which glaciers kept growing through three suborbital cooling events within this period, which were associated with iceberg discharge in the North Atlantic and cooling over Greenland, is unclear. Here we reconstruct parallel records of sea surface and air temperatures from marine microfossil and pollen data, respectively, from two sediment cores collected within the northern subtropical gyre. The thermal gradient between the cold air and warmer sea increased throughout the MIS5a/4 transition, and was marked by three intervals of even more pronounced thermal gradients associated with the C20, C19 and C18' cold events. We argue that the warm ocean surface along the western European margin provided a source of moisture that was transported, through northward-tracking storms, to feed ice sheets in colder Greenland, northern Europe and the Arctic.

  11. The Effects of Air Pollution and Temperature on COPD.

    PubMed

    Hansel, Nadia N; McCormack, Meredith C; Kim, Victor

    2016-06-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12-16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature-both heat and cold-have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  12. Flame Speeds of Methane-Air, Propane-Air, and Ethylene-Air Mixtures at Low Initial Temperatures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L; Heimel, Sheldon

    1952-01-01

    Flame speeds were determined for methane-air, propane-air, and ethylene-air mixtures at -73 C and for methane-air mixtures at -132 C. The data extend the curves of maximum flame speed against initial mixture temperature previously established for the range from room temperature to 344 C. Empirical equations for maximum flame speed u(cm/ sec) as a function of initial mixture temperature T(sub O) were determined to be as follows: for methane, for T(sub O) from 141 to 615 K, u = 8 + 0.000160 T(sub O)(exp 2.11); for propane, for T(sub O) from 200 to 616 K, u = 10 + 0.000342 T(sub O)(exp 2.00); for ethylene, for T(sub O) from 200 to 617 K, u = 10 + 0.00259 T(sub O)(exp 1.74). Relative flame speeds at low initial temperatures were predicted within approximately 20 percent by either the thermal theory as presented by Semenov or by the diffusion theory of Tanford and Pease. The same order was found previously for high initial temperatures. The low-temperature data were also found to extend the linear correlations between maximum flame speed and calculated equilibrium active-radical concentrations, which were established by the previously reported high-temperature data.

  13. Drier Air, Lower Temperatures, and Triggering of Paroxysmal Atrial Fibrillation

    PubMed Central

    Nguyen, Jennifer L.; Link, Mark S.; Luttmann-Gibson, Heike; Laden, Francine; Schwartz, Joel; Wessler, Benjamin S.; Mittleman, Murray A.; Gold, Diane R.; Dockery, Douglas W.

    2015-01-01

    Background The few previous studies on the onset of paroxysmal atrial fibrillation and meteorologic conditions have focused on outdoor temperature and hospital admissions, but hospital admissions are a crude indicator of atrial fibrillation incidence, and studies have found other weather measures in addition to temperature to be associated with cardiovascular outcomes. Methods Two hundred patients with dual chamber implantable cardioverter-defibrillators were enrolled and followed prospectively from 2006 to 2010 for new onset episodes of atrial fibrillation. The date and time of arrhythmia episodes documented by the implanted cardioverter-defibrillators were linked to meteorologic data and examined using a case-crossover analysis. We evaluated associations with outdoor temperature, apparent temperature, air pressure, and three measures of humidity (relative humidity, dew point, and absolute humidity). Results Of the 200 enrolled patients, 49 patients experienced 328 atrial fibrillation episodes lasting ≥30 seconds. Lower temperatures in the prior 48 hours were positively associated with atrial fibrillation. Lower absolute humidity (ie, drier air) had the strongest and most consistent association: each 0.5 g/m3 decrease in the prior 24 hours increased the odds of atrial fibrillation by 4% (95% confidence interval [CI]: 0%, 7%) and by 5% (95% CI: 2%, 8%) for exposure in the prior 2 hours. Results were similar for dew point but slightly weaker. Conclusions Recent exposure to drier air and lower temperatures were associated with the onset of atrial fibrillation among patients with known cardiac disease, supporting the hypothesis that meteorologic conditions trigger acute cardiovascular episodes. PMID:25756220

  14. Attributing surface temperature trends in the presence of natural variability: progress regarding the warming hiatus and unresolved challenges

    NASA Astrophysics Data System (ADS)

    Smoliak, B. V.; Hartmann, D. L.; Booth, J. F.

    2013-12-01

    That the observed amplitude of year-to-year climate variations are sometimes large relative to trends on time scales less than 30 years poses an ongoing challenge for detection and attribution studies, as well as the public perception of climate change. For example, despite the long term warming of the climate system, observations indicate that global average surface temperature has not risen appreciably since about 1998, when a major El Niño event occurred in the tropical Pacific. This post-1998 'warming hiatus' is well documented on the basis of global-mean, annual-mean surface temperature, but it remains poorly understood at finer spatial and temporal scales and its existence has not been unambiguously attributed to natural or anthropogenic forcings. Using observations we confirm that the warming hiatus is primarily associated with the boreal cold season. On the basis of a set of empirically-derived adjustments accounting for the influence of three known sources of natural variability, we demonstrate that the hiatus is largely a reflection of internal variability associated with spontaneously generated fluctuations of the El Nino/Southern Oscillation and extratropical atmospheric teleconnection patterns. Results are discussed in terms of their significance at spatial scales ranging from the entire globe down to the local scale, distinguishing between land and ocean and cold season and warm season.

  15. Mesoscale climatic simulation of surface air temperature cooling by highly reflective greenhouses in SE Spain.

    PubMed

    Campra, Pablo; Millstein, Dev

    2013-01-01

    A long-term local cooling trend in surface air temperature has been monitored at the largest concentration of reflective greenhouses in the world, at the Province of Almeria, SE Spain, associated with a dramatic increase in surface albedo in the area. The availability of reliable long-term climatic field data at this site offers a unique opportunity to test the skill of mesoscale meteorological models describing and predicting the impacts of land use change on local climate. Using the Weather Research and Forecast (WRF) mesoscale model, we have run a sensitivity experiment to simulate the impact of the observed surface albedo change on monthly and annual surface air temperatures. The model output showed a mean annual cooling of 0.25 °C associated with a 0.09 albedo increase, and a reduction of 22.8 W m(-2) of net incoming solar radiation at surface. Mean reduction of summer daily maximum temperatures was 0.49 °C, with the largest single-day decrease equal to 1.3 °C. WRF output was evaluated and compared with observations. A mean annual warm bias (MBE) of 0.42 °C was estimated. High correlation coefficients (R(2) > 0.9) were found between modeled and observed values. This study has particular interest in the assessment of the potential for urban temperature cooling by cool roofs deployment projects, as well as in the evaluation of mesoscale climatic models performance. PMID:24074145

  16. An updated global grid point surface air temperature anomaly data set: 1851--1990

    SciTech Connect

    Sepanski, R.J.; Boden, T.A.; Daniels, R.C.

    1991-10-01

    This document presents land-based monthly surface air temperature anomalies (departures from a 1951--1970 reference period mean) on a 5{degree} latitude by 10{degree} longitude global grid. Monthly surface air temperature anomalies (departures from a 1957--1975 reference period mean) for the Antarctic (grid points from 65{degree}S to 85{degree}S) are presented in a similar way as a separate data set. The data were derived primarily from the World Weather Records and the archives of the United Kingdom Meteorological Office. This long-term record of temperature anomalies may be used in studies addressing possible greenhouse-gas-induced climate changes. To date, the data have been employed in generating regional, hemispheric, and global time series for determining whether recent (i.e., post-1900) warming trends have taken place. This document also presents the monthly mean temperature records for the individual stations that were used to generate the set of gridded anomalies. The periods of record vary by station. Northern Hemisphere station data have been corrected for inhomogeneities, while Southern Hemisphere data are presented in uncorrected form. 14 refs., 11 figs., 10 tabs.

  17. A Worldwide Plan to Eliminate Global Warming, Air Pollution, and Energy Instability With Wind, Water, and Sunlight (WWS)

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.; Delucchi, M. A.

    2011-12-01

    Global warming, air pollution mortality, and energy insecurity are three of the most significant problems facing the world today. This talk discusses a plan to solve the problems by powering 100% of the world's energy for all purposes, including electricity, transportation, industrial processes, and heating/cooling, with wind, water, and sunlight (WWS) within the next 20-40 years. It reviews and ranks major proposed energy solutions to global warming, air pollution mortality, and energy insecurity while considering other impacts of the proposed solutions, such as on water supply, land use, resource availability, reliability, wildlife, and catastrophic risk. It then evaluates a scenario for powering the world on the energy options determined to be the best while also considering materials, transmission infrastructure, costs, and politics. The study concludes that powering the world with WWS electric power technologies and a conversion from combustion to electricity and electrolytically-produced hydrogen is the cleanest and safest method of solving these problems. Due to the efficiency of electricity, such a conversion reduces world power demand by 30%. Methods of ensuring reliability of WWS electric power are available and will be demonstrated. We also conclude that neither liquid biofuels for transportation (including ethanol or biodiesel from any source), solid biofuels for home heating and cooking, biomass for electricity, conventional or fracked natural gas for electricity or transportation, nuclear power, nor coal with carbon capture (clean coal) are nearly so clean or safe as WWS technologies so are not recommended, either as bridge technologies or in the long term. Our plan calls for all new energy to be supplied by WWS-electricity-hydrogen resources no later than 2030 and all existing non-WWS infrastructure to be eliminated no later than 2050. We find that the plan is technically and economically feasible but politically challenging.

  18. Modeling daily average stream temperature from air temperature and watershed area

    NASA Astrophysics Data System (ADS)

    Butler, N. L.; Hunt, J. R.

    2012-12-01

    Habitat restoration efforts within watersheds require spatial and temporal estimates of water temperature for aquatic species especially species that migrate within watersheds at different life stages. Monitoring programs are not able to fully sample all aquatic environments within watersheds under the extreme conditions that determine long-term habitat viability. Under these circumstances a combination of selective monitoring and modeling are required for predicting future geospatial and temporal conditions. This study describes a model that is broadly applicable to different watersheds while using readily available regional air temperature data. Daily water temperature data from thirty-eight gauges with drainage areas from 2 km2 to 2000 km2 in the Sonoma Valley, Napa Valley, and Russian River Valley in California were used to develop, calibrate, and test a stream temperature model. Air temperature data from seven NOAA gauges provided the daily maximum and minimum air temperatures. The model was developed and calibrated using five years of data from the Sonoma Valley at ten water temperature gauges and a NOAA air temperature gauge. The daily average stream temperatures within this watershed were bounded by the preceding maximum and minimum air temperatures with smaller upstream watersheds being more dependent on the minimum air temperature than maximum air temperature. The model assumed a linear dependence on maximum and minimum air temperature with a weighting factor dependent on upstream area determined by error minimization using observed data. Fitted minimum air temperature weighting factors were consistent over all five years of data for each gauge, and they ranged from 0.75 for upstream drainage areas less than 2 km2 to 0.45 for upstream drainage areas greater than 100 km2. For the calibration data sets within the Sonoma Valley, the average error between the model estimated daily water temperature and the observed water temperature data ranged from 0.7

  19. Warming Temperatures Threaten Water Supplies in the Pacific Northwest by Shrinking Mountain Glaciers

    NASA Astrophysics Data System (ADS)

    Bachmann, M.; Curtin, L.

    2013-12-01

    Receding maritime glaciers in the Pacific Northwest confer a strong resistance to climate change impacts on the timing but not peak flow rates of the streams and rivers into which they melt. Since 1957 the U.S. Geological Survey has been measuring glacier mass balance and immediate downstream hydrology at South Cascade Glacier in Washington State, and this multi-decadal record exhibits significantly less hydrologic disturbance in the glacially supported Cascade River than in an adjacent non-glaciated basin. The average timing of peak base flow at the Middle Tarn gaging station (12181090) below South Cascade Glacier now occurs 3 days earlier than it did 56 years ago, but occurs 24 days earlier on the adjacent non-glaciated Salix Creek gage (12181200). Baseflow separation was conducted using a recursive digital filter following Eckhardt 2005 and records from multiple sites were collated using a double mass analysis after Linsley et al. 1980. Summer temperatures have risen 3.5 degrees Celsius at South Cascade Glacier since 1957, resulting in a net mass loss of approximately 45% of glacier ice volume. As Northwest glaciers continue to recede in future years, hydrological impacts from a warming climate which are currently moderated by glacial contribution to streamflow are anticipated to materialize, resulting in earlier and more severe peak flows in rivers in the North Cascades. Linsley, Ray K., Kohler, Max Adam, Paulhus, Joseph H., 1982, Hydrology for Engineers: New York, McGraw-Hill, 508 p. Eckhardt, K., 2005, How to construct recursive digital filters for baseflow separation: Hydrol. Process., v. 19, p. 507-515.

  20. Advances in Fast Response Acoustically Derived Air Temperature Measurements

    NASA Astrophysics Data System (ADS)

    Bogoev, Ivan; Jacobsen, Larry; Horst, Thomas; Conrad, Benjamin

    2016-04-01

    Fast-response accurate air-temperature measurements are required when estimating turbulent fluxes of heat, water and carbon dioxide by open-path eddy-covariance technique. In comparison with contact thermometers like thermocouples, ultra-sonic thermometers do not suffer from solar radiation loading, water vapor condensation and evaporative cooling effects. Consequently they have the potential to provide more accurate true air temperature measurements. The absolute accuracy of the ultrasonic thermometer is limited by the following parameters: the distance between the transducer pairs, transducer delays associated with the electrical-acoustic signal conversion that vary with temperature, components of the wind vector that are normal to the ultrasonic paths, and humidity. The distance between the transducer pairs is commonly obtained by coordinate measuring machine. Improved accuracy demonstrated in this study results from increased stiffness in the anemometer head to better maintain the ultrasonic path-length distances. To further improve accuracy and account for changes in transducer delays and distance as a function of temperature, these parameters are characterized in a zero-wind chamber over the entire operating temperature range. When the sonic anemometer is combined with a co-located fast-response water vapor analyzer, like in the IRGASON instrument, speed of sound can be compensated for humidity effects on a point-by-point basis resulting in a true fast-response air temperature measurement. Laboratory test results show that when the above steps are implemented in the calibration of the ultrasonic thermometer air-temperature accuracy better than ±0.5 degrees Celsius can be achieved over the entire operating range. The approach is also validated in a field inter-comparison with an aspirated thermistor probe mounted in a radiation shield.

  1. The effect of slightly warm temperature on work performance and comfort in open-plan offices - a laboratory study.

    PubMed

    Maula, H; Hongisto, V; Östman, L; Haapakangas, A; Koskela, H; Hyönä, J

    2016-04-01

    The aim of the study was to determine the effect of a temperature of 29°C on performance in tasks involving different cognitive demands and to assess the effect on perceived performance, subjective workload, thermal comfort, perceived working conditions, cognitive fatigue, and somatic symptoms in a laboratory with realistic office environment. A comparison was made with a temperature of 23°C. Performance was measured on the basis of six different tasks that reflect different stages of cognitive performance. Thirty-three students participated in the experiment. The exposure time was 3.5 h in both thermal conditions. Performance was negatively affected by slightly warm temperature in the N-back working memory task. Temperature had no effect on performance in other tasks focusing on psychomotor, working memory, attention, or long-term memory capabilities. Temperature had no effect on perceived performance. However, slightly warm temperature caused concentration difficulties. Throat symptoms were found to increase over time at 29°C, but no temporal change was seen at 23°C. No effect of temperature on other symptoms was found. As expected, the differences in thermal comfort were significant. Women perceived a temperature of 23°C colder than men. PMID:25866136

  2. Near Decade Long Tropospheric Air Temperature and Specific Humidity Records from AIRS for CMIP5 Model Evaluation

    NASA Astrophysics Data System (ADS)

    Tian, B.; Fetzer, E.; Kahn, B. H.; Teixeira, J.; Manning, E.; Hearty, T. J.

    2012-12-01

    The peer-reviewed analyses of multi-model outputs from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) experiments will be the most important basis for the next Intergovernmental Panel on Climate Change (IPCC) Assessment Report (AR5). To increase the fidelity of the IPCC AR5, an Obs4MIPs project has been initiated to collect some well-established and well-documented datasets, to organize them according to the CMIP5 model output requirements, and makes them available to the science community for CMIP5 model evaluation. The NASA Atmospheric Infrared Sounder (AIRS) project has produced monthly mean tropospheric air temperature (ta, K) and specific humidity (hus, kg/kg) products as part of the Obs4MIPS project. In this paper, we first describe these two AIRS datasets in terms of data description, origin, validation and caveats for model-observation comparison. We then document the climatological mean features of these two AIRS datasets and compare them to those from NASA's Modern Era Retrospective analysis for Research and Applications (MERRA) for AIRS data validation and CMIP5 model simulations for CMIP5 model evaluation. As expected, the 9-year AIRS data show several well-known climatological features of tropospheric ta and hus, such as the strong meridional and vertical gradients of tropospheric ta and hus and strong zonal gradient of tropospheric hus. AIRS data also show the strong connections between the tropospheric hus, atmospheric circulation and deep convection. In comparison to MERRA, AIRS seems to be colder in the free troposphere but warmer in the boundary layer with differences typically less than 1 K. AIRS is wetter (~10%) in the tropical boundary layer but drier (around 30%) in the tropical free troposphere and the extratropical troposphere. In particular, the large AIRS-MERRA hus differences are mainly located in the cloudy regions, such as the Intertropical Convergence Zone (ITCZ), the South Pacific Convergence Zone (SPCZ) and the

  3. Keeping warm with fur in cold water: entrainment of air in hairy surfaces

    NASA Astrophysics Data System (ADS)

    Nasto, Alice; Regli, Marianne; Brun, Pierre-Thomas; Clanet, Christophe; Hosoi, Anette

    2015-11-01

    Instead of relying on a thick layer of body fat for insulation as many aquatic mammals do, fur seals and otters trap air in their dense fur for insulation in cold water. Using a combination of model experiments and theory, we rationalize this mechanism of air trapping underwater for thermoregulation. For the model experiments, hairy surfaces are fabricated using laser cut molds and casting samples with PDMS. Modeling the hairy texture as a network of capillary tubes, the imbibition speed of water into the hairs is obtained through a balance of hydrostatic pressure and viscous stress. In this scenario, the bending of the hairs and capillary forces are negligible. The maximum diving depth that can be achieved before the hairs are wetted to the roots is predicted from a comparison of the diving speed and imbibition speed. The amount of air that is entrained in hairy surfaces is greater than what is expected for classic Landau-Levich-Derjaguin plate plunging. A phase diagram with the parameters from experiments and biological data allows a comparison of the model system and animals.

  4. The mass and speed dependence of meteor air plasma temperatures

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  5. CARS Temperature and Species Measurements For Air Vehicle Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Gord, James R.; Grisch, Frederic; Klimenko, Dmitry; Clauss, Walter

    2005-01-01

    The coherent anti-Stokes Raman spectroscopy (CARS) method has recently been used in the United States and Europe to probe several different types of propulsion systems for air vehicles. At NASA Langley Research Center in the United States, CARS has been used to simultaneously measure temperature and the mole fractions of N2, O2 and H2 in a supersonic combustor, representative of a scramjet engine. At Wright- Patterson Air Force Base in the United States, CARS has been used to simultaneously measure temperature and mole fractions of N2, O2 and CO2, in the exhaust stream of a liquid-fueled, gas-turbine combustor. At ONERA in France and the DLR in Germany researchers have used CARS to measure temperature and species concentrations in cryogenic LOX-H2 rocket combustion chambers. The primary aim of these measurements has been to provide detailed flowfield information for computational fluid dynamics (CFD) code validation.

  6. Microwave temperature profiler for clear air turbulence prediction

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    1992-01-01

    A method is disclosed for determining Richardson Number, Ri, or its reciprocal, RRi, for clear air prediction using measured potential temperature and determining the vertical gradient of potential temperature, d(theta)/dz. Wind vector from the aircraft instrumentation versus potential temperature, dW/D(theta), is determined and multiplies by d(theta)/dz to obtain dW/dz. Richardson number or its reciprocal is then determined from the relationship Ri = K(d theta)/dz divided by (dW/dz squared) for use in detecting a trend toward a threshold value for the purpose of predicting clear air turbulence. Other equations for this basic relationship are disclosed together with the combination of other atmospheric observables using multiple regression techniques.

  7. Symmetric scaling properties in global surface air temperature anomalies

    NASA Astrophysics Data System (ADS)

    Varotsos, Costas A.; Efstathiou, Maria N.

    2015-08-01

    We have recently suggested "long-term memory" or internal long-range correlation within the time-series of land-surface air temperature (LSAT) anomalies in both hemispheres. For example, an increasing trend in the LSAT anomalies is followed by another one at a different time in a power-law fashion. However, our previous research was mainly focused on the overall long-term persistence, while in the present study, the upward and downward scaling dynamics of the LSAT anomalies are analysed, separately. Our results show that no significant fluctuation differences were found between the increments and decrements in LSAT anomalies, over the whole Earth and over each hemisphere, individually. On the contrary, the combination of land-surface air and sea-surface water temperature anomalies seemed to cause a departure from symmetry and the increments in the land and sea surface temperature anomalies appear to be more persistent than the decrements.

  8. Fiber optic distributed temperature sensing for the determination of air temperature

    NASA Astrophysics Data System (ADS)

    de Jong, S. A. P.; Slingerland, J. D.; van de Giesen, N. C.

    2015-01-01

    This paper describes a method to correct for the effect of solar radiation in atmospheric distributed temperature sensing (DTS) applications. By using two cables with different diameters, one can determine what temperature a zero diameter cable would have. Such a virtual cable would not be affected by solar heating and would take on the temperature of the surrounding air. With two unshielded cable pairs, one black pair and one white pair, good results were obtained given the general consensus that shielding is needed to avoid radiation errors (WMO, 2010). The correlations between standard air temperature measurements and air temperatures derived from both cables of colors had a high correlation coefficient (r2=0.99) and a RMSE of 0.38 °C, compared to a RMSE of 2.40 °C for a 3.0 mm uncorrected black cable. A thin white cable measured temperatures that were close to air temperature measured with a nearby shielded thermometer (RMSE of 0.61 °C). The temperatures were measured along horizontal cables with an eye to temperature measurements in urban areas, but the same method can be applied to any atmospheric DTS measurements, and for profile measurements along towers or with balloons and quadcopters.

  9. The Effects of Air Pollution and Temperature on COPD

    PubMed Central

    Hansel, Nadia N.; McCormack, Meredith C.; Kim, Victor

    2016-01-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12–16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature—both heat and cold—have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  10. Observations of northern latitude ground-surface and surface-air temperatures

    NASA Astrophysics Data System (ADS)

    Woodbury, Allan D.; Bhuiyan, A. K. M. H.; Hanesiak, John; Akinremi, O. O.

    2009-04-01

    Note that the magnitude of temperature increases reconstructed from borehole records seems to contrast with some proxy based reconstructions of surface air temperature (SAT) that indicate lower amounts of warming over the same period. We present data suggesting that ground and snow cover may bias climate reconstructions based on BT in portions of the Canadian northwest. Eight sites west of the Canadian cordillera, were examined for long-term SAT and GST changes. At seven of these sites precise borehole temperature profiles are used for the first time since the 1960s, thereby exploring the linkage between GST and SAT. New readings were made at four of these locations. All sites showed significant increasing SAT trends, in terms of annual mean minimum and maximum temperatures. Over a 54 year period, the minimum temperatures increased between 1.1°C and 1.5°C while the maximum increased between 0.8°C and 1.5°C, among those eight stations. Observations of GST at those sites, however, showed no obvious climate induced perturbations. Therefore, we believe that a trend in our area towards an increase in SAT temperatures only over the winter and spring is being masked by freeze thaw and latent energy effects. These results are important, particularly in northern locations where ground and snow cover may play an important role in creating a seasonal bias in GST reconstructions from borehole surveys.

  11. Spatial interpolation of monthly mean air temperature data for Latvia

    NASA Astrophysics Data System (ADS)

    Aniskevich, Svetlana

    2016-04-01

    Temperature data with high spatial resolution are essential for appropriate and qualitative local characteristics analysis. Nowadays the surface observation station network in Latvia consists of 22 stations recording daily air temperature, thus in order to analyze very specific and local features in the spatial distribution of temperature values in the whole Latvia, a high quality spatial interpolation method is required. Until now inverse distance weighted interpolation was used for the interpolation of air temperature data at the meteorological and climatological service of the Latvian Environment, Geology and Meteorology Centre, and no additional topographical information was taken into account. This method made it almost impossible to reasonably assess the actual temperature gradient and distribution between the observation points. During this project a new interpolation method was applied and tested, considering auxiliary explanatory parameters. In order to spatially interpolate monthly mean temperature values, kriging with external drift was used over a grid of 1 km resolution, which contains parameters such as 5 km mean elevation, continentality, distance from the Gulf of Riga and the Baltic Sea, biggest lakes and rivers, population density. As the most appropriate of these parameters, based on a complex situation analysis, mean elevation and continentality was chosen. In order to validate interpolation results, several statistical indicators of the differences between predicted values and the values actually observed were used. Overall, the introduced model visually and statistically outperforms the previous interpolation method and provides a meteorologically reasonable result, taking into account factors that influence the spatial distribution of the monthly mean temperature.

  12. Male moths optimally balance take-off thoracic temperature and warm-up duration to reach a pheromone source quickly.

    PubMed

    Crespo, José G; Vickers, Neil J; Goller, Franz

    2014-12-01

    Animal activities, such as foraging and reproduction, are constrained by decisions about how to allocate energy and time efficiently. Overall, male moths invest less in reproduction than females, but they are thought to engage in a scramble competition for access to females that advertise readiness to mate by releasing sexual pheromones. However, before male moths can follow the pheromone, they often need to heat their flight muscles by shivering to produce sufficient power for sustained flight. Here, we show that Helicoverpa zea males that sense the female pheromone at high ambient temperatures take off with higher thoracic temperature, shiver for less time and warm up faster than males tested at lower ambient temperatures. These higher take-off temperatures translate into higher airspeeds, underscoring the importance of thoracic temperature for flight performance. Furthermore, shorter combined duration for warm-up and pheromone-mediated optomotor anemotaxis is consistent with the idea that males engage in scramble competition for access to females in nature. Our results strongly suggest that male moths minimize the time between perceiving the female's pheromone signal and arriving at the source by optimizing thermoregulatory behaviour and temperature-dependent flight performance in accordance with ambient temperature conditions. Our finding that moths engage in a trade-off between rapid flight initiation and suboptimal flight performance suggests a sensorimotor control mechanism that involves a complex interaction with the thermal environment. PMID:25386029

  13. Male moths optimally balance take-off thoracic temperature and warm-up duration to reach a pheromone source quickly

    PubMed Central

    Crespo, José G.; Vickers, Neil J.; Goller, Franz

    2014-01-01

    Animal activities, such as foraging and reproduction, are constrained by decisions about how to allocate energy and time efficiently. Overall, male moths invest less in reproduction than females, but they are thought to engage in a scramble competition for access to females that advertise readiness to mate by releasing sexual pheromones. However, before male moths can follow the pheromone, they often need to heat their flight muscles by shivering to produce sufficient power for sustained flight. Here, we show that Helicoverpa zea males that sense the female pheromone at high ambient temperatures take off with higher thoracic temperature, shiver for less time and warm up faster than males tested at lower ambient temperatures. These higher take-off temperatures translate into higher airspeeds, underscoring the importance of thoracic temperature for flight performance. Furthermore, shorter combined duration for warm-up and pheromone-mediated optomotor anemotaxis is consistent with the idea that males engage in scramble competition for access to females in nature. Our results strongly suggest that male moths minimize the time between perceiving the female's pheromone signal and arriving at the source by optimizing thermoregulatory behaviour and temperature-dependent flight performance in accordance with ambient temperature conditions. Our finding that moths engage in a trade-off between rapid flight initiation and suboptimal flight performance suggests a sensorimotor control mechanism that involves a complex interaction with the thermal environment. PMID:25386029

  14. Air pollution, temperature and pediatric influenza in Brisbane, Australia.

    PubMed

    Xu, Zhiwei; Hu, Wenbiao; Williams, Gail; Clements, Archie C A; Kan, Haidong; Tong, Shilu

    2013-09-01

    Previous studies have demonstrated the importance of weather variables in influencing the incidence of influenza. However, the role of air pollution is often ignored in identifying the environmental drivers of influenza. This research aims to examine the impacts of air pollutants and temperature on the incidence of pediatric influenza in Brisbane, Australia. Lab-confirmed daily data on influenza counts among children aged 0-14years in Brisbane from 2001 January 1st to 2008 December 31st were retrieved from Queensland Health. Daily data on maximum and minimum temperatures for the same period were supplied by the Australian Bureau of Meteorology. Winter was chosen as the main study season due to it having the highest pediatric influenza incidence. Four Poisson log-linear regression models, with daily pediatric seasonal influenza counts as the outcome, were used to examine the impacts of air pollutants (i.e., ozone (O3), particulate matter≤10μm (PM10) and nitrogen dioxide (NO2)) and temperature (using a moving average of ten days for these variables) on pediatric influenza. The results show that mean temperature (Relative risk (RR): 0.86; 95% Confidence Interval (CI): 0.82-0.89) was negatively associated with pediatric seasonal influenza in Brisbane, and high concentrations of O3 (RR: 1.28; 95% CI: 1.25-1.31) and PM10 (RR: 1.11; 95% CI: 1.10-1.13) were associated with more pediatric influenza cases. There was a significant interaction effect (RR: 0.94; 95% CI: 0.93-0.95) between PM10 and mean temperature on pediatric influenza. Adding the interaction term between mean temperature and PM10 substantially improved the model fit. This study provides evidence that PM10 needs to be taken into account when evaluating the temperature-influenza relationship. O3 was also an important predictor, independent of temperature. PMID:23911338

  15. Spring Temperatures Alone Cannot Explain Timing of Budburst of Boreal-Temperate Tree Species under Experimental Warming

    NASA Astrophysics Data System (ADS)

    Montgomery, R. A.; Reich, P. B.; Rich, R. L.; Stefanski, A.

    2011-12-01

    Phenology, the timing of seasonal biological events such as budburst, blossom dates, bird migration and insect development, is critical to understanding species interactions (e.g. pollination, herbivory); determines growing season length in many (i.e. seasonal) terrestrial ecosystems; and can play a role in determining species range limits. There is ample evidence that plant and animal phenology has changed in recent decades. For trees in seasonally cold climates, change is most commonly manifested as earlier budburst, likely caused by earlier onset of warming temperatures in spring. Indeed, it is often assumed that one of the major phenological responses of temperate and boreal forest ecosystems to climate change will be earlier leafing and concomitantly, a longer growing season. However, spring warming interacts with other factors such as winter chilling and photoperiod to determine timing of spring leafing. For example, warmer winters could reduce the duration and amount of chilling experienced by dormant buds and lead to delayed budburst. Despite knowledge that such interactions exist, we know little about the interactive mechanisms by which various cues influence budburst in forest tree species or whether species differ in sensitivity to those cues. This gap hinders our ability to predict phenological responses and their ecological impacts under future climate scenarios. Over the past three years, we have conducted studies of leafing phenology, germination, photosynthesis, respiration, and growth of seedlings of ten boreal-temperate tree species subjected to experimental warming using infrared heat lamps and soil heating cables. Seedlings were planted into plots receiving ambient, +1.8°C or +3.6°C temperature treatments in open, aspen forest at the Cloquet Forestry Center, Cloquet, MN, USA (46°31' N, 92°30' W, 386 m a.s.l.; 4.5°C MAT, 807 mm MAP). While all species responded to warming by advancing the absolute date of budburst, several lines of evidence

  16. Requirements for high-temperature air-cooled central receivers

    SciTech Connect

    Wright, J.D.; Copeland, R.J.

    1983-12-01

    The design of solar thermal central receivers will be shaped by the end user's need for energy. This paper identifies the requirements for receivers supplying heat for industrial processes or electric power generation in the temperature range 540 to 1000/sup 0/C and evaluates the effects of the requirements on air-cooled central receivers. Potential IPH applications are identified as large baseload users that are located some distance from the receiver. In the electric power application, the receiver must supply heat to a pressurized gas power cycle. The difficulty in providing cost-effective thermal transport and thermal storage for air-cooled receivers is a critical problem.

  17. Can air temperature be used to project influences of climate change on stream temperature?

    USGS Publications Warehouse

    Arismendi, Ivan; Safeeq, Mohammad; Dunham, Jason B.; Johnson, Sherri L.

    2014-01-01

    Worldwide, lack of data on stream temperature has motivated the use of regression-based statistical models to predict stream temperatures based on more widely available data on air temperatures. Such models have been widely applied to project responses of stream temperatures under climate change, but the performance of these models has not been fully evaluated. To address this knowledge gap, we examined the performance of two widely used linear and nonlinear regression models that predict stream temperatures based on air temperatures. We evaluated model performance and temporal stability of model parameters in a suite of regulated and unregulated streams with 11–44 years of stream temperature data. Although such models may have validity when predicting stream temperatures within the span of time that corresponds to the data used to develop them, model predictions did not transfer well to other time periods. Validation of model predictions of most recent stream temperatures, based on air temperature–stream temperature relationships from previous time periods often showed poor performance when compared with observed stream temperatures. Overall, model predictions were less robust in regulated streams and they frequently failed in detecting the coldest and warmest temperatures within all sites. In many cases, the magnitude of errors in these predictions falls within a range that equals or exceeds the magnitude of future projections of climate-related changes in stream temperatures reported for the region we studied (between 0.5 and 3.0 °C by 2080). The limited ability of regression-based statistical models to accurately project stream temperatures over time likely stems from the fact that underlying processes at play, namely the heat budgets of air and water, are distinctive in each medium and vary among localities and through time.

  18. Can air temperatures be used to project influences of climate change on stream temperatures?

    NASA Astrophysics Data System (ADS)

    Arismendi, I.; Safeeq, M.; Dunham, J.; Johnson, S. L.

    2013-12-01

    The lack of available in situ stream temperature records at broad spatiotemporal scales have been recognized as a major limiting factor in the understanding of thermal behavior of stream and river systems. This has motivated the promotion of a wide variety of models that use surrogates for stream temperatures including a regression approach that uses air temperature as the predictor variable. We investigate the long-term performance of widely used linear and non-linear regression models between air and stream temperatures to project the latter in future climate scenarios. Specifically, we examine the temporal variability of the parameters that define each of these models in long-term stream and air temperature datasets representing relatively natural and highly human-influenced streams. We selected 25 sites with long-term records that monitored year-round daily measurements of stream temperature (daily mean) in the western United States (California, Oregon, Idaho, Washington, and Alaska). Surface air temperature data from each site was not available. Therefore, we calculated daily mean surface air temperature for each site in contiguous US from a 1/16-degree resolution gridded surface temperature data. Our findings highlight several limitations that are endemic to linear or nonlinear regressions that have been applied in many recent attempts to project future stream temperatures based on air temperature. Our results also show that applications over longer time periods, as well as extrapolation of model predictions to project future stream temperatures are unlikely to be reliable. Although we did not analyze a broad range of stream types at a continental or global extent, our analysis of stream temperatures within the set of streams considered herein was more than sufficient to illustrate a number of specific limitations associated with statistical projections of stream temperature based on air temperature. Radar plots of Nash-Sutcliffe efficiency (NSE) values for

  19. Temperature during egg formation and the effect of climate warming on egg size in a small songbird

    NASA Astrophysics Data System (ADS)

    Potti, Jaime

    2008-05-01

    The predicted effects of recent climate warming on egg size in birds are controversial, as only two long-term studies have been reported, with contrasting results. Long-term data on egg size variation are analyzed in relation to ambient temperatures in a southern European population of pied flycatchers where breeding phenology has not matched the spring advancement in the last decades. Cross-sectional, population analyses indicated that egg breadth, but not egg length, has decreased significantly along the 16-year period, leading to marginally non-significant decreases in egg volume. Longitudinal, individual analyses revealed that despite females consistently laying larger eggs when they experienced warmer temperatures during the prelaying and laying periods, there was an overall negative response - i.e. decreasing egg volume and breadth with increasing spring (May) average temperatures - across individuals. This trend is hypothesised to be caused by the mismatched breeding phenology, in relation to climate warming, of this population. Except in the unlikely cases of populations capable of perfectly synchronising their phenology to changes in their environment, maladjustments are likely for traits such as egg size, which depend strongly on female condition. Slight changes or absence thereof in breeding dates may be followed by mismatched dates, in terms of food abundance, for optimal egg formation, which would be reflected in smaller average egg size, contrary to early predictions on the effects of climate warming on bird egg size.

  20. Air and Ground Surface Temperature Relations in a Mountainous Basin, Wolf Creek, Yukon Territory

    NASA Astrophysics Data System (ADS)

    Roadhouse, Emily A.

    related to the winter air temperatures. The application of n-factor modeling techniques within the permafrost region, and the verification of these techniques for a range of natural surfaces, is essential to the determination of the thermal and physical response to potential climate warming in permafrost regions. The presence of temperature inversions presents a unique challenge to permafrost probability mapping in mountainous terrain. While elsewhere the existence of permafrost can be linearly related to elevation, the presence of frequent inversions challenges this assumption, affecting permafrost distribution in ways that the current modeling techniques cannot accurately predict. At sites across the Yukon, inversion-prone sites were predominantly situated in U-shaped valleys, although open slopes, mid-slope ridges and plains were also identified. Within the Wolf Creek basin and surrounding area, inversion episodes have a measurable effect on local air temperatures, occurring during the fall and winter seasons along the Mount Sima trail, and year-round in the palsa valley. Within the discontinuous permafrost zone, where average surface temperatures are often close to zero, even a relatively small change in temperature in the context of future climate change could have a widespread impact on permafrost distribution.

  1. Snow removal and ambient air temperature effects on forest soil temperatures in northern Vermont

    NASA Astrophysics Data System (ADS)

    Wang, D.; Decker, K. L.; Waite, C.; Scherbatskoy, T.

    2003-12-01

    We measured deciduous forest soil temperatures under control (unmanipulated) and snow-free (where snow is manually removed) conditions for four winters (at three soil depths) to determine effects of a snow cover reduction such as may occur as a result of climate change on Vermont forest soils. The four winters we studied were characterized as:`cold and snowy', `warm with low snow', `cold with low snow', and `cool with low snow'. Snow-free soils were colder than controls at 5 and 15 cm depth for all years, and at all depths in the two cold winters. Soil thermal variability generally decreased with both increased snow cover and soil depth. The effect of snow cover on soil freeze-thaw events was highly dependent on both the depth of snow and the soil temperature. Snow kept the soil warm and reduced soil temperature variability, but often this caused soil to remain near 0 deg C, resulting in more freeze-thaw events under snow at one or more soil depths. During the `cold snowy' winter, soils under snow had daily averages consistently >0 deg C, whereas snow-free soil temperatures commonly dropped below -3 deg C. During the `warm' year, temperatures of soil under snow were often lower than those of snow-free soils. The warmer winter resulted in less snow cover to insulate soil from freezing in the biologically active top 30 cm. The possible consequences of increased soil freezing include more root mortality and nutrient loss which would potentially alter ecosystem dynamics, decrease productivity of some tree species, and increase sugar maple mortality in northern hardwood forests.

  2. RELATIONSHIP BETWEEN WATER TEMPERATURES AND AIR TEMPERATURES FOR CENTRAL US STREAMS

    EPA Science Inventory

    An analysis of the relationship between air and stream water temperature records for 11 rivers located in the central United States was conducted. he reliability of commonly available water temperature records was shown to be of unequal quality. imple linear relationships between...

  3. Air breathing in the Arctic: influence of temperature, hypoxia, activity and restricted air access on respiratory physiology of the Alaska blackfish Dallia pectoralis

    PubMed Central

    Lefevre, Sjannie; Damsgaard, Christian; Pascale, Desirae R.; Nilsson, Göran E.; Stecyk, Jonathan A. W.

    2014-01-01

    The Alaska blackfish (Dallia pectoralis) is an air-breathing fish native to Alaska and the Bering Sea islands, where it inhabits lakes that are ice-covered in the winter, but enters warm and hypoxic waters in the summer to forage and reproduce. To understand the respiratory physiology of this species under these conditions and the selective pressures that maintain the ability to breathe air, we acclimated fish to 5°C and 15°C and used respirometry to measure: standard oxygen uptake () in normoxia (19.8 kPa PO2) and hypoxia (2.5 kPa), with and without access to air; partitioning of standard in normoxia and hypoxia; maximum and partitioning after exercise; and critical oxygen tension (Pcrit). Additionally, the effects of temperature acclimation on haematocrit, haemoglobin oxygen affinity and gill morphology were assessed. Standard was higher, but air breathing was not increased, at 15°C or after exercise at both temperatures. Fish acclimated to 5°C or 15°C increased air breathing to compensate and fully maintain standard in hypoxia. Fish were able to maintain through aquatic respiration when air was denied in normoxia, but when air was denied in hypoxia, standard was reduced by ∼30–50%. Pcrit was relatively high (5 kPa) and there were no differences in Pcrit, gill morphology, haematocrit or haemoglobin oxygen affinity at the two temperatures. Therefore, Alaska blackfish depends on air breathing in hypoxia and additional mechanisms must thus be utilised to survive hypoxic submergence during the winter, such as hypoxia-induced enhancement in the capacities for carrying and binding blood oxygen, behavioural avoidance of hypoxia and suppression of metabolic rate. PMID:25394628

  4. Air Temperature Estimation over the Third Pole Using MODIS LST

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Zhang, F.; Ye, M.; Che, T.

    2015-12-01

    The Third Pole is centered on the Tibetan Plateau (TP), which is the highest large plateau around the world with extremely complex terrain and climate conditions, resulting in very scarce meteorological stations especially in the vast west region. For these unobserved areas, the remotely sensed land surface temperature (LST) can greatly contribute to air temperature estimation. In our research we utilized the MODIS LST production from both TERRA and AQUA to estimate daily mean air temperature over the TP using multiple statistical models. Other variables used in the models include longitudes, latitudes, Julian day, solar zenith, NDVI and elevation. To select a relatively optimal model, we chose six popular and representative statistical models as candidate models including the multiple linear regression (MLR), the partial least squares regression (PLS), back propagate neural network (BPNN), support vector regression (SVR), random forests (RF) and Cubist regression (CR). The performances of the six models were compared for each possible combination of LSTs at four satellite pass times and two quality situations. Eventually a ranking table consisting of optimal models for each LST combination and quality situation was built up based on the validation results. By this means, the final production is generated providing daily mean air temperature with the least cloud blockage and acceptable accuracy. The average RMSEs of cross validation are mostly around 2℃. Stratified validations were also performed to test the expansibility to unobserved and high-altitude areas of the final models selected.

  5. Temperature-induced water stress in high-latitude forests in response to natural and anthropogenic warming.

    PubMed

    Trahan, Matthew W; Schubert, Brian A

    2016-02-01

    The Arctic is particularly sensitive to climate change, but the independent effects of increasing atmospheric CO2 concentration (pCO2 ) and temperature on high-latitude forests are poorly understood. Here, we present a new, annually resolved record of stable carbon isotope (δ(13) C) data determined from Larix cajanderi tree cores collected from far northeastern Siberia in order to investigate the physiological response of these trees to regional warming. The tree-ring record, which extends from 1912 through 1961 (50 years), targets early twentieth-century warming (ETCW), a natural warming event in the 1920s to 1940s that was limited to Northern hemisphere high latitudes. Our data show that net carbon isotope fractionation (Δ(13) C), decreased by 1.7‰ across the ETCW, which is consistent with increased water stress in response to climate warming and dryer soils. To investigate whether this signal is present across the northern boreal forest, we compiled published carbon isotope data from 14 high-latitude sites within Europe, Asia, and North America. The resulting dataset covered the entire twentieth century and spanned both natural ETCW and anthropogenic Late Twentieth-Century Warming (~0.7 °C per decade). After correcting for a ~1‰ increase in Δ(13) C in response to twentieth century pCO2 rise, a significant negative relationship (r = -0.53, P < 0.0001) between the average, annual Δ(13) C values and regional annual temperature anomalies is observed, suggesting a strong control of temperature on the Δ(13) C value of trees growing at high latitudes. We calculate a 17% increase in intrinsic water-use efficiency within these forests across the twentieth century, of which approximately half is attributed to a decrease in stomatal conductance in order to conserve water in response to drying conditions, with the other half being attributed to increasing pCO2 . We conclude that annual tree-ring records from northern high-latitude forests record the effects of

  6. Air - Ground - Bedrock Temperature Coupling, Its Monitoring at Borehole Climate Observatories

    NASA Astrophysics Data System (ADS)

    Cermák, V.

    2012-04-01

    Reconstructing ground surface temperature (GST) histories from present-day temperature-depth logs is now generally accepted as one of the independent and physically justified method to obtain information about the past climate history on the time scale of hundreds to thousands years. Any temperature change at the Earth`s surface slowly propagates downward and deeper we go farther back in time the measured temperature carries certain memory on what has happened on the surface in the past. Due to diffusive character of the process, however, the resolution quickly decreases for the remote events and the reconstructed GST at a given moment is a weighted average of temperature over a certain period of time. For better understanding of the temperature state in the subsurface T(z) logs can be suitably completed with long-run temperature-time monitoring at selected depth intervals, namely within the near-surface active layer affected by seasonal temperature variations (usually uppermost 30-40 m). In addition to GST inversions applied on deep T(z) profiles existing all over the world, several permanent borehole climate observatories were actually established in the last two decades to test the validity of the assumption that GST variations track the SAT (surface air temperature) changes as well as to study various environmental/local effects, such as the vegetation cover type/change, rain/snow precipitation, thawing/melting/freezing, etc. which controls the whole heat transfer process. Long-term monitoring of the shallow subsurface temperature field in suitably geographically located sites may additionally also help to understand the different conditions in e.g. urban vs. countryside environments and to assess the potential anthropogenic contribution to the present-day warming rate within the natural climate variability. This presentation summarizes main results obtained at the Czech borehole sites since 1992 completed with brief comparison of similar results collected

  7. Air Cooling for High Temperature Power Electronics (Presentation)

    SciTech Connect

    Waye, S.; Musselman, M.; King, C.

    2014-09-01

    Current emphasis on developing high-temperature power electronics, including wide-bandgap materials such as silicon carbide and gallium nitride, increases the opportunity for a completely air-cooled inverter at higher powers. This removes the liquid cooling system for the inverter, saving weight and volume on the liquid-to-air heat exchanger, coolant lines, pumps, and coolant, replacing them with just a fan and air supply ducting. We investigate the potential for an air-cooled heat exchanger from a component and systems-level approach to meet specific power and power density targets. A proposed baseline air-cooled heat exchanger design that does not meet those targets was optimized using a parametric computational fluid dynamics analysis, examining the effects of heat exchanger geometry and device location, fixing the device heat dissipation and maximum junction temperature. The CFD results were extrapolated to a full inverter, including casing, capacitor, bus bar, gate driver, and control board component weights and volumes. Surrogate ducting was tested to understand the pressure drop and subsequent system parasitic load. Geometries that met targets with acceptable loads on the system were down-selected for experimentation. Nine baseline configuration modules dissipated the target heat dissipation, but fell below specific power and power density targets. Six optimized configuration modules dissipated the target heat load, exceeding the specific power and power density targets. By maintaining the same 175 degrees C maximum junction temperature, an optimized heat exchanger design and higher device heat fluxes allowed a reduction in the number of modules required, increasing specific power and power density while still maintaining the inverter power.

  8. Complexity analysis of the air temperature and the precipitation time series in Serbia

    NASA Astrophysics Data System (ADS)

    Mimić, G.; Mihailović, D. T.; Kapor, D.

    2015-11-01

    In this paper, we have analyzed the time series of daily values for three meteorological elements, two continuous and a discontinuous one, i.e., the maximum and minimum air temperature and the precipitation. The analysis was done based on the observations from seven stations in Serbia from the period 1951-2010. The main aim of this paper was to quantify the complexity of the annual values for the mentioned time series and to calculate the rate of its change. For that purpose, we have used the sample entropy and the Kolmogorov complexity as the measures which can indicate the variability and irregularity of a given time series. Results obtained show that the maximum temperature has increasing trends in the given period which points out a warming, ranged in the interval 1-2 °C. The increasing temperature indicates the higher internal energy of the atmosphere, changing the weather patterns, manifested in the time series. The Kolmogorov complexity of the maximum temperature time series has statistically significant increasing trends, while the sample entropy has increasing but statistically insignificant trend. The trends of complexity measures for the minimum temperature depend on the location. Both complexity measures for the precipitation time series have decreasing trends.

  9. Global surface air temperature variations: 1851-1984

    SciTech Connect

    Jones, P.D.; Raper, S.C.B.; Kelly, P.M.

    1986-11-01

    Many attempts have been made to combine station surface air temperature data into an average for the Northern Hemisphere. Fewer attempts have been made for the Southern Hemisphere because of the unavailability of data from the Antarctic mainland before the 1950s and the uncertainty of making a hemispheric estimate based solely on land-based analyses for a hemisphere that is 80% ocean. Past estimates have been based largely on data from the World Weather Records (Smithsonian Institution, 1927, 1935, 1947, and U.S. Weather Bureau, 1959-82) and have been made without considerable effort to detect and correct station inhomogeneities. Better estimates for the Southern Hemisphere are now possible because of the availability of 30 years of climatological data from Antarctica. The mean monthly surface air temperature anomalies presented in this package for the than those previously published because of the incorporation of data previously hidden away in archives and the analysis of station homogeneity before estimation.

  10. Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    SciTech Connect

    Abdelaziz, Omar; Munk, Jeffrey D.; Shrestha, Som S.; Linkous, Randall Lee; Goetzler, William; Guernsey, Matt; Kassuga, Theo

    2015-08-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

  11. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    SciTech Connect

    Abdelaziz, Omar; Shrestha, Som S.; Munk, Jeffrey D.; Linkous, Randall Lee; Goetzler, William; Guernsey, Matt; Kassuga, Theo

    2015-10-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

  12. Changes in extreme temperature and precipitation events in the Loess Plateau (China) during 1960-2013 under global warming

    NASA Astrophysics Data System (ADS)

    Sun, Wenyi; Mu, Xingmin; Song, Xiaoyan; Wu, Dan; Cheng, Aifang; Qiu, Bing

    2016-02-01

    In recent decades, extreme climatic events have been a major issue worldwide. Regional assessments on various climates and geographic regions are needed for understanding uncertainties in extreme events' responses to global warming. The objective of this study was to assess the annual and decadal trends in 12 extreme temperature and 10 extreme precipitation indices in terms of intensity, frequency, and duration over the Loess Plateau during 1960-2013. The results indicated that the regionally averaged trends in temperature extremes were consistent with global warming. The occurrence of warm extremes, including summer days (SU), tropical nights (TR), warm days (TX90), and nights (TN90) and a warm spell duration indicator (WSDI), increased by 2.76 (P < 0.01), 1.24 (P < 0.01), 2.60 (P = 0.0003), 3.41 (P < 0.01), and 0.68 (P = 0.0041) days/decade during the period of 1960-2013, particularly, sharp increases in these indices occurred in 1985-2000. Over the same period, the occurrence of cold extremes, including frost days (FD), ice days (ID), cold days (TX10) and nights (TN10), and a cold spell duration indicator (CSDI) exhibited decreases of - 3.22 (P < 0.01), - 2.21 (P = 0.0028), - 2.71 (P = 0.0028), - 4.31 (P < 0.01), and - 0.69 (P = 0.0951) days/decade, respectively. Moreover, extreme warm events in most regions tended to increase while cold indices tended to decrease in the Loess Plateau, but the trend magnitudes of cold extremes were greater than those of warm extremes. The growing season (GSL) in the Loess Plateau was lengthened at a rate of 3.16 days/decade (P < 0.01). Diurnal temperature range (DTR) declined at a rate of - 0.06 °C /decade (P = 0.0931). Regarding the precipitation indices, the annual total precipitation (PRCPTOT) showed no obvious trends (P = 0.7828). The regionally averaged daily rainfall intensity (SDII) exhibited significant decreases (- 0.14 mm/day/decade, P = 0.0158), whereas consecutive dry days (CDD) significantly increased (1.96 days

  13. Industrial applications of MHD high temperature air heater technology

    NASA Astrophysics Data System (ADS)

    Saari, D. P.; Fenstermacher, J. E.; White, L. R.; Marksberry, C. L.

    1981-12-01

    The MHD high temperature air heater (HTAH) requires technology beyond the current state-of-the-art of industrial regenerative heaters. Specific aspects of HTAH technology which may find other application include refractory materials and valves resistant to the high temperature, corrosive, slag-bearing gas, materials resistant to cyclic thermal stresses, high temperature support structures for the cored brick bed, regenerative heater operating techniques for preventing accumulation of slag in the heater, and analytical tools for computing regenerative heater size, cost, and performance. Areas where HTAH technology may find application include acetylene/ethylene production processes, flash pyrolysis of coal, high temperature gas reactors, coal gasification processes, various metallurgical processes, waste incineration, and improvements to existing regenerator technology such as blast furnace stoves and glass tank regenerators.

  14. Evidence of Lunar Phase Influence on Global Surface Air Temperatures

    NASA Technical Reports Server (NTRS)

    Anyamba, Ebby; Susskind, Joel

    2000-01-01

    Intraseasonal oscillations appearing in a newly available 20-year record of satellite-derived surface air temperature are composited with respect to the lunar phase. Polar regions exhibit strong lunar phase modulation with higher temperatures occurs near full moon and lower temperatures at new moon, in agreement with previous studies. The polar response to the apparent lunar forcing is shown to be most robust in the winter months when solar influence is minimum. In addition, the response appears to be influenced by ENSO events. The highest mean temperature range between full moon and new moon in the polar region between 60 deg and 90 deg latitude was recorded in 1983, 1986/87, and 1990/91. Although the largest lunar phase signal is in the polar regions, there is a tendency for meridional equatorward progression of anomalies in both hemispheres so that the warning in the tropics occurs at the time of the new moon.

  15. Solar Cycle and Anthropogenic Forcing of Surface-Air Temperature at Armagh Observatory, Northern Ireland

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2010-01-01

    A comparison of 10-yr moving average (yma) values of Armagh Observatory (Northern Ireland) surface-air temperatures with selected solar cycle indices (sunspot number (SSN) and the Aa geomagnetic index (Aa)), sea-surface temperatures in the Nino 3.4 region, and Mauna Loa carbon dioxide (CO2) (MLCO2) atmospheric concentration measurements reveals a strong correlation (r = 0.686) between the Armagh temperatures and Aa, especially, prior to about 1980 (r = 0.762 over the interval of 1873-1980). For the more recent interval 1963-2003, the strongest correlation (r = 0.877) is between Armagh temperatures and MLCO2 measurements. A bivariate fit using both Aa and Mauna Loa values results in a very strong fit (r = 0.948) for the interval 1963-2003, and a trivariate fit using Aa, SSN, and Mauna Loa values results in a slightly stronger fit (r = 0.952). Atmospheric CO2 concentration now appears to be the stronger driver of Armagh surface-air temperatures. An increase of 2 C above the long-term mean (9.2 C) at Armagh seems inevitable unless unabated increases in anthropogenic atmospheric gases can be curtailed. The present growth in 10-yma Armagh temperatures is about 0.05 C per yr since 1982. The present growth in MLCO2 is about 0.002 ppmv, based on an exponential fit using 10-yma values, although the growth appears to be steepening, thus, increasing the likelihood of deleterious effects attributed to global warming.

  16. Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming

    NASA Astrophysics Data System (ADS)

    Sawall, Yvonne; Al-Sofyani, Abdulmoshin; Hohn, Sönke; Banguera-Hinestroza, Eulalia; Voolstra, Christian R.; Wahl, Martin

    2015-03-01

    Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12° latitudes featuring a steep temperature gradient between the northern (28.5°N, 21-27°C) and southern (16.5°N, 28-33°C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29°C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals.

  17. Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming.

    PubMed

    Sawall, Yvonne; Al-Sofyani, Abdulmoshin; Hohn, Sönke; Banguera-Hinestroza, Eulalia; Voolstra, Christian R; Wahl, Martin

    2015-01-01

    Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12° latitudes featuring a steep temperature gradient between the northern (28.5°N, 21-27°C) and southern (16.5°N, 28-33°C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29°C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals. PMID:25754672

  18. Antarctic Sea ice variations and seasonal air temperature relationships

    NASA Technical Reports Server (NTRS)

    Weatherly, John W.; Walsh, John E.; Zwally, H. J.

    1991-01-01

    Data through 1987 are used to determine the regional and seasonal dependencies of recent trends of Antarctic temperature and sea ice. Lead-lag relationships involving regional sea ice and air temperature are systematically evaluated, with an eye toward the ice-temperature feedbacks that may influence climatic change. Over the 1958-1087 period the temperature trends are positive in all seasons. For the 15 years (l973-l987) for which ice data are available, the trends are predominantly positive only in winter and summer, and are most strongly positive over the Antarctic Peninsula. The spatially aggregated trend of temperature for this latter period is small but positive, while the corresponding trend of ice coverage is small but negative. Lag correlations between seasonal anomalies of the two variables are generally stronger with ice lagging the summer temperatures and with ice leading the winter temperatures. The implication is that summer temperatures predispose the near-surface waters to above-or below-normal ice coverage in the following fall and winter.

  19. The effect of temperature on different Salmonella serotypes during warm seasons in a Mediterranean climate city, Adelaide, Australia.

    PubMed

    Milazzo, A; Giles, L C; Zhang, Y; Koehler, A P; Hiller, J E; Bi, P

    2016-04-01

    Changing trends in foodborne disease are influenced by many factors, including temperature. Globally and in Australia, warmer ambient temperatures are projected to rise if climate change continues. Salmonella spp. are a temperature-sensitive pathogen and rising temperature can have a substantial effect on disease burden affecting human health. We examined the relationship between temperature and Salmonella spp. and serotype notifications in Adelaide, Australia. Time-series Poisson regression models were fit to estimate the effect of temperature during warmer months on Salmonella spp. and serotype cases notified from 1990 to 2012. Long-term trends, seasonality, autocorrelation and lagged effects were included in the statistical models. Daily Salmonella spp. counts increased by 1·3% [incidence rate ratio (IRR) 1·013, 95% confidence interval (CI) 1·008-1·019] per 1 °C rise in temperature in the warm season with greater increases observed in specific serotype and phage-type cases ranging from 3·4% (IRR 1·034, 95% CI 1·008-1·061) to 4·4% (IRR 1·044, 95% CI 1·024-1·064). We observed increased cases of S. Typhimurium PT9 and S. Typhimurium PT108 notifications above a threshold of 39 °C. This study has identified the impact of warm season temperature on different Salmonella spp. strains and confirms higher temperature has a greater effect on phage-type notifications. The findings will contribute targeted information for public health policy interventions, including food safety programmes during warmer weather. PMID:26522685

  20. Global Warming?

    ERIC Educational Resources Information Center

    Eichman, Julia Christensen; Brown, Jeff A.

    1994-01-01

    Presents information and data on an experiment designed to test whether different atmosphere compositions are affected by light and temperature during both cooling and heating. Although flawed, the experiment should help students appreciate the difficulties that researchers face when trying to find evidence of global warming. (PR)

  1. Validation and development of existing and new RAOB-based warm-season convective wind forecasting tools for Cape Canaveral Air Force Station and Kennedy Space Center

    NASA Astrophysics Data System (ADS)

    McCue, Mitchell Hollis

    Using a 15-year (1995 to 2009) climatology of 1500 UTC warm-season (May through September) rawinsonde observation (RAOB) data from the Cape Canaveral Air Force Station (CCAFS) Skid Strip (KXMR) and 5 minute wind data from 36 wind towers on CCAFS and Kennedy Space Center (KSC), several convective wind forecasting techniques currently employed by the 45th Weather Squadron (45 WS) were evaluated. Present forecasting methods under evaluation include examining the vertical equivalent potential temperature (theta e) profile, vertical profiles of wind spend and direction, and several wet downburst forecasting indices. Although previous research found that currently used wet downburst forecasting methods showed little promise for forecasting convective winds, it was carried out with a very small sample, limiting the reliability of the results. Evaluation versus a larger 15-year dataset was performed to truly assess the forecasting utility of these methods in the central Florida warm-season convective environment. In addition, several new predictive analytic based forecast methods for predicting the occurrence of warm-season convection and its associated wind gusts were developed and validated. This research was performed in order to help the 45 WS better forecast not only which days are more likely to produce convective wind gusts, but also to better predict which days are more likely to yield warning criteria wind events of 35 knots or greater, should convection be forecasted. Convective wind forecasting is a very challenging problem that requires new statistically based modeling techniques since conventional meteorologically based methods do not perform well. New predictive analytic based forecasting methods were constructed using R statistical software and incorporate several techniques including multiple linear regression, logistic regression, multinomial logistic regression, classification and regression trees (CART), and ensemble CART using bootstrapping. All of

  2. Controls of air temperature variability over an Alpine Glacier

    NASA Astrophysics Data System (ADS)

    Shaw, Thomas; Brock, Ben; Ayala, Álvaro; Rutter, Nick

    2016-04-01

    Near surface air temperature (Ta) is one of the most important controls on energy exchange between a glacier surface and the overlying atmosphere. However, not enough detail is known about the controls on Ta across a glacier due to sparse data availability. Recent work has provided insights into variability of Ta along glacier centre-lines in different parts of the world, yet there is still a limited understanding of off-centreline variability in Ta and how best to estimate it from distant off-glacier locations. We present a new dataset of distributed 2m Ta records for the Tsanteleina Glacier in Northwest Italy from July-September, 2015. Data provide detailed information of lateral (across-glacier) and centre-line variations in Ta, with ~20,000 hourly observations from 17 locations. The suitability of different vertical temperature gradients (VTGs) in estimating air temperature is considered under a range of meteorological conditions and from different forcing locations. A key finding is that local VTGs account for a lot of Ta variability under a broad range of climatic conditions. However, across-glacier variability is found to be significant, particularly for high ambient temperatures and for localised topographic depressions. The relationship of spatial Ta patterns with regional-scale reanalysis data and alternative Ta estimation methodologies are also presented. This work improves the knowledge of local scale Ta variations and their importance to melt modelling.

  3. An isoline separating relatively warm from relatively cool wintertime forest surface temperatures for the southeastern United States

    NASA Astrophysics Data System (ADS)

    Wickham, J.; Wade, T. G.; Riitters, K. H.

    2014-09-01

    Forest-oriented climate mitigation policies promote forestation as a means to increase uptake of atmospheric carbon to counteract global warming. Some have pointed out that a carbon-centric forest policy may be overstated because it discounts biophysical aspects of the influence of forests on climate. In extra-tropical regions, many climate models have shown that forests tend to be warmer than grasslands and croplands because forest albedos tend to be lower than non-forest albedos. A lower forest albedo results in higher absorption of solar radiation and increased sensible warming that is not offset by the cooling effects of carbon uptake in extra-tropical regions. However, comparison of forest warming potential in the context of climate models is based on a coarse classification system of tropical, temperate, and boreal. There is considerable variation in climate within the broad latitudinal zonation of tropical, temperate, and boreal, and the relationship between biophysical (albedo) and biogeochemical (carbon uptake) mechanisms may not be constant within these broad zones. We compared wintertime forest and non-forest surface temperatures for the southeastern United States and found that forest surface temperatures shifted from being warmer than non-forest surface temperatures north of approximately 36°N to cooler south of 36°N. Our results suggest that the biophysical aspects of forests' influence on climate reinforce the biogeochemical aspects of forests' influence on climate south of 36°N. South of 36°N, both biophysical and biogeochemical properties of forests appear to support forestation as a climate mitigation policy. We also provide some quantitative evidence that evergreen forests tend to have cooler wintertime surface temperatures than deciduous forests that may be attributable to greater evapotranspiration rates.

  4. High efficiency power generation from coal and wastes utilizing high temperature air combustion technology (Part 2: Thermal performance of compact high temperature air preheater and MEET boiler)

    SciTech Connect

    Iwahashi, Takashi; Kosaka, Hitoshi; Yoshida, Nobuhiro

    1998-07-01

    The compact high temperature air preheater and the MEET boiler, which are critical components of the MEET system, are the direct evolutions of the high temperature air combustion technology. Innovative hardware concept for a compact high temperature air preheater has been proposed, and preliminary experiment using the MEET-I high temperature air preheater based on this concept successfully demonstrated continuous high temperature air generation with almost no temperature fluctuation. A preliminary heat transfer calculation for the MEET boiler showed that regenerative combustion using high temperature air is quite effective for radiative heat transfer augmentation in a boiler, which will lead to significant downsizing of a boiler. The heat transfer characteristics in the MEET boiler were experimentally measured and the heat transfer promotion effect and the uniform heat transfer field were confirmed. Moreover, it was understood that excellent combustion with the low BTU gas of about 3,000 kcal/m{sup 3} was done.

  5. Spatiotemporal changes in extreme ground surface temperatures and the relationship with air temperatures in the Three-River Source Regions during 1980-2013

    NASA Astrophysics Data System (ADS)

    Luo, Dongliang; Jin, Huijun; Lü, Lanzhi; Zhou, Jian

    2016-02-01

    Climate changes are affecting plant growth, ecosystem evolution, hydrological processes, and water resources in the Three-River Source Regions (TRSR). Daily ground surface temperature (GST) and air temperature (Ta) recordings from 12 meteorological stations illustrated trends and characteristics of extreme GST and Ta in the TRSR during 1980-2013. We used the Mann-Kendall test and Sen's slope estimate to analyze 12 temperature extreme indices as recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The mean annual ground surface temperatures (MAGST) are 2.4-4.3 °C higher than the mean annual air temperatures (MAAT) in the TRSR. The increasing trends of the MAGST are all higher than those of the MAAT. The multi-year average maximum GST (28.1 °C) is much higher than that of the Ta (7.6 °C), while the minimum GST (-8.7 °C) is similar to that of the minimum Ta (-6.9 °C). The minimum temperature trends are more significant than those of the maximum temperature and are consistent with temperature trends in other regions of China. Different spatiotemporal patterns of GST extremes compared to those of Ta may result from greater warming of the ground surface. Consequently, the difference between the GST and Ta increased. These findings have implications for variations of surface energy balance, sensible heat flux, ecology, hydrology, and permafrost.

  6. Storm type effects on super Clausius-Clapeyron scaling of intense rainstorm properties with air temperature

    NASA Astrophysics Data System (ADS)

    Molnar, P.; Fatichi, S.; Gaál, L.; Szolgay, J.; Burlando, P.

    2015-04-01

    Extreme precipitation is thought to increase with warming at rates similar to or greater than the water vapour holding capacity of the air at ~ 7% °C-1, the so-called Clausius-Clapeyron (CC) rate. We present an empirical study of the variability in the rates of increase in precipitation intensity with air temperature using 30 years of 10 min and 1 h data from 59 stations in Switzerland. The analysis is conducted on storm events rather than fixed interval data, and divided into storm type subsets based on the presence of lightning which is expected to indicate convection. The average rates of increase in extremes (95th percentile) of mean event intensity computed from 10 min data are 6.5% °C-1 (no-lightning events), 8.9% °C-1 (lightning events) and 10.7% °C-1 (all events combined). For peak 10 min intensities during an event the rates are 6.9% °C-1 (no-lightning events), 9.3% °C-1 (lightning events) and 13.0% °C-1 (all events combined). Mixing of the two storm types exaggerates the relations to air temperature. Doubled CC rates reported by other studies are an exception in our data set, even in convective rain. The large spatial variability in scaling rates across Switzerland suggests that both local (orographic) and regional effects limit moisture supply and availability in Alpine environments, especially in mountain valleys. The estimated number of convective events has increased across Switzerland in the last 30 years, with 30% of the stations showing statistically significant changes. The changes in intense convective storms with higher temperatures may be relevant for hydrological risk connected with those events in the future.

  7. -induced continental warming

    NASA Astrophysics Data System (ADS)

    Kamae, Youichi; Watanabe, Masahiro; Kimoto, Masahide; Shiogama, Hideo

    2014-11-01

    In this the second of a two-part study, we examine the physical mechanisms responsible for the increasing contrast of the land-sea surface air temperature (SAT) in summertime over the Far East, as observed in recent decades and revealed in future climate projections obtained from a series of transient warming and sensitivity experiments conducted under the umbrella of the Coupled Model Intercomparison Project phase 5. On a global perspective, a strengthening of land-sea SAT contrast in the transient warming simulations of coupled atmosphere-ocean general circulation models is attributed to an increase in sea surface temperature (SST). However, in boreal summer, the strengthened contrast over the Far East is reproduced only by increasing atmospheric CO2 concentration. In response to SST increase alone, the tropospheric warming over the interior of the mid- to high-latitude continents including Eurasia are weaker than those over the surrounding oceans, leading to a weakening of the land-sea SAT contrast over the Far East. Thus, the increasing contrast and associated change in atmospheric circulation over East Asia is explained by CO2-induced continental warming. The degree of strengthening of the land-sea SAT contrast varies in different transient warming scenarios, but is reproduced through a combination of the CO2-induced positive and SST-induced negative contributions to the land-sea contrast. These results imply that changes of climate patterns over the land-ocean boundary regions are sensitive to future scenarios of CO2 concentration pathways including extreme cases.

  8. Practical ways to abate air and water pollution worldwide including a unique way to significantly curb global warming

    SciTech Connect

    Snell, J.R.

    1998-07-01

    This paper points out that in the next 50 years it will largely be the developing countries of the world which will continue to industrialize rapidly and hence pollute the water and air of not only their countries but that this pollution is becoming global (80% of the World's population.) From the author's 25 years of consulting experience in the developing countries, their greatest need is to have available to them low cost, innovative processes for pollution abatement will be neglected and the whole world will suffer immensely. The paper discusses in some detail the type of innovative low cost methods which have successfully been used in the categories of wastewater and solid wastes and names 6 other categories where many others exist. All these innovative methods need to be discovered, listed, and tested for quality and dependability, and then made widely available. Large Environmental Engineering Universities and International Consulting Engineering firms need to be organized to undertake these important tasks. The paper also points out the connection between Global Warming and the Solid waste industry and shows how it can be controlled inexpensively by employing a new, unique, and rapid method of converting municipal refuse into methane and then using that to make electricity. Information given in this paper could lead to a vast reduction in future pollution, with the resulting better global health and at the same time save trillions of dollars.

  9. The Solutions Project: Educating the Public and Policy Makers About Solutions to Global Warming, Air Pollution, and Energy Security

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.

    2015-12-01

    Three major global problems of our times are global warming, air pollution mortality and morbidity, and energy insecurity. Whereas, policy makers with the support of the public must implement solutions to these problems, it is scientists and engineers who are best equipped to evaluate technically sound, optimal, and efficient solutions. Yet, a disconnect exists between information provided by scientists and engineers and policies implemented. Part of the reason is that scientific information provided to policy makers and the public is swamped out by information provided by lobbyists and another part is the difficulty in providing information to the hundreds of millions of people who need it rather than to just a few thousand. What other ways are available, aside from issuing press releases on scientific papers, for scientists to disseminate information? Three growing methods are through social media, creative media, and storytelling. The Solutions Project is a non-profit non-governmental organization whose goal is to bring forth scientific information about 100% clean, renewable energy plans to the public, businesses, and policy makers using these and related tools. Through the use of social media, the development of engaging internet and video content, and storytelling, the group hopes to increase the dissemination of information for social good. This talk discusses the history and impacts to date of this group and its methods. Please see www.thesolutionsproject.org and 100.org for more information.

  10. Air Temperature estimation from Land Surface temperature and solar Radiation parameters

    NASA Astrophysics Data System (ADS)

    Lazzarini, Michele; Eissa, Yehia; Marpu, Prashanth; Ghedira, Hosni

    2013-04-01

    Air Temperature (AirT) is a fundamental parameter in a wide range of applications such as climate change studies, weather forecast, energy balance modeling, efficiency of Photovoltaic (PV) solar cells, etc. Air temperature data are generally obtained through regular measurements from meteorological stations. The distribution of these stations is normally sparse, so the spatial pattern of this parameter cannot be accurately estimated by interpolation methods. This work investigated the relationship between Air Temperature measured at meteorological stations and spatially contiguous measurements derived from Remote Sensing techniques, such as Land Surface Temperature (LST) maps, emissivity maps and shortwave radiation maps with the aim of creating a continuous map of AirT. For LST and emissivity, MSG-SEVIRI LST product from Land Surface Analysis Satellite Applications Facility (LSA-SAF) has been used. For shortwave radiation maps, an Artificial Neural Networks ensemble model has been developed and previously tested to create continuous maps from Global Horizontal Irradiance (GHI) point measurements, utilizing six thermal channels of MSG-SEVIRI. The testing sites corresponded to three meteorological stations located in the United Arab Emirates (UAE), where in situ measurements of Air Temperature were available. From the starting parameters, energy fluxes and net radiation have been calculated, in order to have information on the incoming and outgoing long-wave radiation and the incoming short-wave radiation. The preliminary analysis (day and Night measurements, cloud free) showed a strong negative correlation (0.92) between Outgoing long-wave radiation - GHI and LST- AirT, with a RMSE of 1.84 K in the AirT estimation from the initial parameters. Regression coefficients have been determined and tested on all the ground stations. The analysis also demonstrated the predominant impact of the incoming short-wave radiation in the AirT hourly variation, while the incoming

  11. Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions

    USGS Publications Warehouse

    Moyes, Andrew B.; Germino, Matthew J.; Kueppers, Lara M.

    2015-01-01

    Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as seasonally dry subalpine and alpine ecosystems continue to warm.

  12. On extreme rainfall intensity increases with air temperature

    NASA Astrophysics Data System (ADS)

    Molnar, Peter; Fatichi, Simone; Paschalis, Athanasios; Gaal, Ladislav; Szolgay, Jan; Burlando, Paolo

    2016-04-01

    The water vapour holding capacity of air increases at about 7% per degree C according to the Clausius-Clapeyron (CC) relation. This is one of the arguments why a warmer future atmosphere, being able to hold more moisture, will generate higher extreme precipitation intensities. However, several empirical studies have recently demonstrated an increase in extreme rain intensities with air temperature above CC rates, in the range 7-14% per degree C worldwide (called super-CC rates). This was observed especially for shorter duration rainfall, i.e. in hourly and finer resolution data (e.g. review in Westra et al., 2014). The super-CC rate was attributed to positive feedbacks between water vapour and the updraft dynamics in convective clouds and lateral supply (convergence) of moisture. In addition, mixing of storm types was shown to be potentially responsible for super-CC rates in empirical studies. Assuming that convective events are accompanied by lightning, we will show on a large rainfall dataset in Switzerland (30 year records of 10-min and 1-hr data from 59 stations) that while the average rate of increase in extreme rainfall intensity (95th percentile) is 6-7% in no-lightning events and 8-9% in lightning events, it is 11-13% per degree C when all events are combined (Molnar et al., 2015). These results are relevant for climate change studies which predict shifts in storm types in a warmer climate in some parts of the world. The observation that extreme rain intensity and air temperature are positively correlated has consequences for the stochastic modelling of rainfall. Most current stochastic models do not explicitly include a direct rain intensity-air temperature dependency beyond applying factors of change predicted by climate models to basic statistics of precipitation. Including this dependency explicitly in stochastic models will allow, for example in the nested modelling approach of Paschalis et al. (2014), the random cascade disaggregation routine to be

  13. Soil and water warming accelerates phenology and down-regulation of leaf photosynthesis of rice plants grown under free-air CO2 enrichment (FACE).

    PubMed

    Adachi, Minaco; Hasegawa, Toshihiro; Fukayama, Hiroshi; Tokida, Takeshi; Sakai, Hidemitsu; Matsunami, Toshinori; Nakamura, Hirofumi; Sameshima, Ryoji; Okada, Masumi

    2014-02-01

    To enable prediction of future rice production in a changing climate, we need to understand the interactive effects of temperature and elevated [CO2] (E[CO2]). We therefore examined if the effect of E[CO2] on the light-saturated leaf photosynthetic rate (Asat) was affected by soil and water temperature (NT, normal; ET, elevated) under open-field conditions at the rice free-air CO2 enrichment (FACE) facility in Shizukuishi, Japan, in 2007 and 2008. Season-long E[CO2] (+200 µmol mol(-1)) increased Asat by 26%, when averaged over two years, temperature regimes and growth stages. The effect of ET (+2°C) on Asat was not significant at active tillering and heading, but became negative and significant at mid-grain filling; Asat in E[CO2]-ET was higher than in ambient [CO2] (A[CO2])-NT by only 4%. Photosynthetic down-regulation at E[CO2] also became apparent at mid-grain filling; Asat compared at the same [CO2] in the leaf cuvette was significantly lower in plants grown in E[CO2] than in those grown in A[CO2]. The additive effects of E[CO2] and ET decreased Asat by 23% compared with that of A[CO2]-NT plants. Although total crop nitrogen (N) uptake was increased by ET, N allocation to the leaves and to Rubisco was reduced under ET and E[CO2] at mid-grain filling, which resulted in a significant decrease (32%) in the maximum rate of ribulose-1,5-bisphosphate carboxylation on a leaf area basis. Because the change in N allocation was associated with the accelerated phenology in E[CO2]-ET plants, we conclude that soil and water warming accelerates photosynthetic down-regulation at E[CO2]. PMID:24406632

  14. Soil and Water Warming Accelerates Phenology and Down-Regulation of Leaf Photosynthesis of Rice Plants Grown Under Free-Air CO2 Enrichment (FACE)

    PubMed Central

    Adachi, Minaco; Hasegawa, Toshihiro; Fukayama, Hiroshi; Tokida, Takeshi; Sakai, Hidemitsu; Matsunami, Toshinori; Nakamura, Hirofumi; Sameshima, Ryoji; Okada, Masumi

    2014-01-01

    To enable prediction of future rice production in a changing climate, we need to understand the interactive effects of temperature and elevated [CO2] (E[CO2]). We therefore examined if the effect of E[CO2] on the light-saturated leaf photosynthetic rate (Asat) was affected by soil and water temperature (NT, normal; ET, elevated) under open-field conditions at the rice free-air CO2 enrichment (FACE) facility in Shizukuishi, Japan, in 2007 and 2008. Season-long E[CO2] (+200 µmol mol−1) increased Asat by 26%, when averaged over two years, temperature regimes and growth stages. The effect of ET (+2°C) on Asat was not significant at active tillering and heading, but became negative and significant at mid-grain filling; Asat in E[CO2]–ET was higher than in ambient [CO2] (A[CO2])–NT by only 4%. Photosynthetic down-regulation at E[CO2] also became apparent at mid-grain filling; Asat compared at the same [CO2] in the leaf cuvette was significantly lower in plants grown in E[CO2] than in those grown in A[CO2]. The additive effects of E[CO2] and ET decreased Asat by 23% compared with that of A[CO2]–NT plants. Although total crop nitrogen (N) uptake was increased by ET, N allocation to the leaves and to Rubisco was reduced under ET and E[CO2] at mid-grain filling, which resulted in a significant decrease (32%) in the maximum rate of ribulose-1,5-bisphosphate carboxylation on a leaf area basis. Because the change in N allocation was associated with the accelerated phenology in E[CO2]–ET plants, we conclude that soil and water warming accelerates photosynthetic down-regulation at E[CO2]. PMID:24406632

  15. Unforced surface air temperature anomalies and their opposite relationship with the TOA energy imbalance at local and global scales

    NASA Astrophysics Data System (ADS)

    Brown, P. T.; Li, W.; Jiang, J. H.; Su, H.

    2015-12-01

    Unforced global mean surface air temperature (Tglobal) is stable in the long-term primarily because warm Tglobal anomalies are associated with enhanced outgoing longwave radiation to space and thus a negative global radiative energy imbalance (Nglobal, positive downward) at the top of the atmosphere (TOA). However, it is shown here that at the local spatial scale, warm unforced Tlocal anomalies tend to be associated with anomalously positive Nlocal imbalances over most of the surface of the planet. It is revealed that this occurs mainly because warm Tlocal anomalies are accompanied by anomalously low surface albedo near sea ice margins and over high altitudes, anomalously low cloud albedo over much of the mid/low-latitudes and an anomalously large water-vapor greenhouse effect over the deep tropical ocean. During warm Tglobal years, the largest negative Nlocal anomalies primarily occur over regions of cool or near-neutral Tlocal anomalies. These results help explain how TOA energy imbalances can act to damp unforced Tglobal anomalies while simultaneously amplifying unforced Tlocal anomalies.

  16. Generation of low-temperature air plasma for food processing

    NASA Astrophysics Data System (ADS)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  17. Air temperature variations on the Atlantic - Arctic boundary since 1802: the low-frequency pattern and ocean teleconnections

    NASA Astrophysics Data System (ADS)

    Wood, K. R.; Overland, J. E.; Jónsson, T.; Smoliak, B. V.

    2010-12-01

    A two-hundred year instrumental record of annual surface air temperature (SAT) in the Atlantic - Arctic boundary region was reconstructed from four station-based composite time series (Fig. 1). Credibility is supported by ice core records, other temperature proxies, and historical evidence. This record (designated TNA) provides new perspective on past climate fluctuations in a region where pivotal climate system processes occur and where unexplained low-frequency variations were observed during the 20th century. TNA shows that the low-frequency pattern of the 20th century does not have a clear analog in the previous century. During the 19th century decadal-scale climate fluctuations occurred in irregular episodes; none were as distinctive as the early 20th century warming event (~1920 to mid-century), which is the most striking historical feature in the record. Evidence of a strong teleconnection between TNA and SST anomalies in the western boundary current - southern recirculation gyre (WBC) region of the North Atlantic Ocean provides an opportunity to reframe the problem of low-frequency variability in the region in terms tractable to theory and empirical investigation. Positive fluctuations in both TNA (and by extension other climate variables associated with it) and SST in the WBC region could be initiated by persistent variations in the large-scale atmospheric circulation that promote the advection of warm maritime air into the Atlantic - Arctic region and simultaneously limit flux-induced cooling in the Nordic Seas and the WBC/recirculation gyre region. This leads to enhanced ocean heat storage in both regions and may consequently reinforce anomalous atmospheric circulation patterns like those observed during the early 20th century warming event. Figure 1. Extended annual mean SAT record for the Atlantic - Arctic boundary region (TNA). The early 20th century warming (ETCW) episode is marked. Regions represented by station-based composite SAT records used in

  18. The Trends of Soil Temperature Change Associated with Air Temperature Change in Korea from 1973 to 2012

    NASA Astrophysics Data System (ADS)

    Lee, Bo-Hyun; Park, Byeong-Hak; Koh, Eun-Hee; Lee, Kang-Kun

    2015-04-01

    Examining long-term trends of the soil temperature can contribute to assessing subsurface thermal environment. The recent 40-year (1973-2012) meteorological data from 14 Korea Meteorological Administration (KMA) stations was analyzed in this study to estimate the temporal variations of air and soil temperatures (at depths 0.5 and 1.0m) in Korea and their relations. The information on regional characteristics of study sites was also collected to investigate the local and regional features influencing the soil temperature. The long-term increasing trends of both air and soil temperatures were estimated by using simple linear regression analysis. The air temperature rise and soil temperature rise were compared for every site to reveal the relation between air and soil temperature changes. In most sites, the proportion of soil temperature rise to air temperature rise was nearly one to one except a few sites. The difference between the air and soil temperature trends at those sites may be attributed to the combined effect of soil properties such as thermal diffusivity and soil moisture content. The impact of urbanization on the air and soil temperature was also investigated in this study. Establishment of the relationship between the air and soil temperatures can help predicting the soil temperature change in a region where no soil temperature data is obtained by using air temperature data. For rigorous establishment of the relationship between soil and air temperatures, more thorough investigation on the soil thermal properties is necessary through additional monitoring and accompanied validation of the proposed relations. Keywords : Soil temperature, Air temperature, Cross-correlation analysis, Soil thermal diffusivity, Urbanization effect Acknowledgement This work was supported by the research project of "Advanced Technology for Groundwater Development and Application in Riversides (Geowater+)" in "Water Resources Management Program (code 11 Technology Innovation C05

  19. What matters most: Are summer stream temperatures more sensitive to changing air temperature, changing discharge, or changing riparian vegetation under future climates?

    NASA Astrophysics Data System (ADS)

    Diabat, M.; Haggerty, R.; Wondzell, S. M.

    2012-12-01

    We investigated stream temperature responses to changes in both air temperature and stream discharge projected for 2040-2060 from downscaled GCMs and changes in the height and canopy density of streamside vegetation. We used Heat Source© calibrated for a 37 km section of the Middle Fork John Day River located in Oregon, USA. The analysis used the multiple-variable-at-a-time (MVAT) approach to simulate various combinations of changes: 3 levels of air warming, 5 levels of stream flow (higher and lower discharges), and 6 types of streamside vegetation. Preliminary results show that, under current discharge and riparian vegetation conditions, projected 2 to 4 °C increase in air temperature will increase the 7-day Average Daily Maximum Temperature (7dADM) by 1 to 2 °C. Changing stream discharge by ±30% changes stream temperature by ±0.5 °C, and the influence of changing discharge is greatest when the stream is poorly shaded. In contrast, the 7dADM could change by as much as 11°C with changes in riparian vegetation from unshaded conditions to heavily shaded conditions along the study section. The most heavily shaded simulations used uniformly dense riparian vegetation over the full 37-km reach, and this vegetation was composed of the tallest trees and densest canopies that can currently occur within the study reach. While this simulation represents an extreme case, it does suggest that managing riparian vegetation to substantially increase stream shade could decrease 7dADM temperatures relative to current temperatures, even under future climates when mean air temperatures have increased from 2 to 4 °C.

  20. Warm Middle Jurassic-Early Cretaceous high-latitude sea-surface temperatures from the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Jenkyns, H. C.; Schouten-Huibers, L.; Schouten, S.; Sinninghe Damsté, J. S.

    2012-02-01

    Although a division of the Phanerozoic climatic modes of the Earth into "greenhouse" and "icehouse" phases is widely accepted, whether or not polar ice developed during the relatively warm Jurassic and Cretaceous Periods is still under debate. In particular, there is a range of isotopic and biotic evidence that favours the concept of discrete "cold snaps", marked particularly by migration of certain biota towards lower latitudes. Extension of the use of the palaeotemperature proxy TEX86 back to the Middle Jurassic indicates that relatively warm sea-surface conditions (26-30 °C) existed from this interval (∼160 Ma) to the Early Cretaceous (∼115 Ma) in the Southern Ocean, with a general warming trend through the Late Jurassic followed by a general cooling trend through the Early Cretaceous. The lowest sea-surface temperatures are recorded from around the Callovian-Oxfordian boundary, an interval identified in Europe as relatively cool, but do not fall below 25 °C. The early Aptian Oceanic Anoxic Event, identified on the basis of published biostratigraphy, total organic carbon and carbon-isotope stratigraphy, records an interval with the lowest, albeit fluctuating Early Cretaceous palaeotemperatures (∼26 °C), recalling similar phenomena recorded from Europe and the tropical Pacific Ocean. Extant belemnite δ18O data, assuming an isotopic composition of waters inhabited by these fossils of -1‰ SMOW, give palaeotemperatures throughout the Upper Jurassic-Lower Cretaceous interval that are consistently lower by ∼14 °C than does TEX86 and the molluscs likely record conditions below the thermocline. The long-term, warm climatic conditions indicated by the TEX86 data would only be compatible with the existence of continental ice if appreciable areas of high altitude existed on Antarctica, and/or in other polar regions, during the Mesozoic Era.

  1. Identifying Modes of Temperature Variability Using AIRS Data.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.; Yung, Y.

    2007-12-01

    We use the Atmospheric Infrared Sounder (AIRS) and Advance Microwave Sounding Unit (AMSU) data obtained on Aqua spacecraft to study mid-tropospheric temperature variability between 2002-2007. The analysis is focused on daily zonal means of the AIRS channel at 2388 1/cm in the CO2 R-branch and the AMSU channel #5 in the 57 GHz Oxygen band, both with weighting function peaking in the mid-troposphere (400 mb) and the matching sea surface temperature from NCEP (Aumann et al., 2007). Taking into account the nonlinear and non- stationary behavior of the temperature we apply the Empirical Mode Decomposition (Huang et al., 1998) to better separate modes of variability. All-sky (cloudy) and clear sky, day and night data are analyzed. In addition to the dominant annual variation, which is nonlinear and latitude dependent, we identified the modes with higher frequency and inter-annual modes. Some trends are visible and we apply stringent criteria to test their statistical significance. References: Aumann, H. H., D. T. Gregorich, S. E. Broberg, and D. A. Elliott, Geophys. Res. Lett., 34, L15813, doi:10.1029/2006GL029191, 2007. Huang, N. E. Z. Shen, S. R. Long, M. C. Wu, H. H. Shih, Q. Zheng, N.-C. Yen, C. C. Tung, and H. H. Liu, Proc. R. Soc. Lond., A 454, 903-995, 1998.

  2. Very low electron temperature in warm dense matter formed by focused picosecond soft x-ray laser pulses

    SciTech Connect

    Ishino, Masahiko Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Pikuz, Tatiana; Skobelev, Igor; Faenov, Anatoly; Inogamov, Nail

    2014-11-14

    We investigated the optical emission from the ablating surfaces induced by the irradiations of soft x-ray laser (SXRL) pulses with the aim of estimation of the maximum electron temperature. No emission signal in the spectral range of 400–800 nm could be observed despite the formation of damage structures on the target surfaces. Hence, we estimated an upper limit for the electron temperature of 0.4–0.7 eV for the process duration of 100–1000 ps. Our results imply that the ablation and/or surface modification by the SXRL is not accompanied by plasma formation but is induced by thermo-mechanical pressure, which is so called a spallative ablation. This spallative ablation process occurs in the low electron temperature region of a non-equilibrium state of warm dense matter.

  3. Hardy exotics species in temperate zone: can “warm water” crayfish invaders establish regardless of low temperatures?

    PubMed Central

    Veselý, Lukáš; Buřič, Miloš; Kouba, Antonín

    2015-01-01

    The spreading of new crayfish species poses a serious risk for freshwater ecosystems; because they are omnivores they influence more than one level in the trophic chain and they represent a significant part of the benthic biomass. Both the environmental change through global warming and the expansion of the pet trade increase the possibilities of their spreading. We investigated the potential of four “warm water” highly invasive crayfish species to overwinter in the temperate zone, so as to predict whether these species pose a risk for European freshwaters. We used 15 specimens of each of the following species: the red swamp crayfish (Procambarus clarkii), the marbled crayfish (Procambarus fallax f. virginalis), the yabby (Cherax destructor), and the redclaw (Cherax quadricarinatus). Specimens were acclimatized and kept for 6.5 months at temperatures simulating the winter temperature regime of European temperate zone lentic ecosystems. We conclude that the red swamp crayfish, marbled crayfish and yabby have the ability to withstand low winter temperatures relevant for lentic habitats in the European temperate zone, making them a serious invasive threat to freshwater ecosystems. PMID:26572317

  4. 1200 years of warm-season temperature variability in central Fennoscandia inferred from tree-ring density

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Linderholm, H. W.; Gunnarson, B. E.; Björklund, J.; Chen, D.

    2015-02-01

    An improved and extended Pinus sylvestris L. (Scots Pine) tree-ring maximum density (MXD) chronology from the central Scandinavian Mountains was used to reconstruct warm-season (April-September) temperature back to 850 CE. Due to systematic bias from differences in elevation (or local environment) of the samples through time, the data was "mean adjusted''. The new reconstruction, called C-Scan, was based on the RSFi standardisation method to preserve mid- and long-term climate variability. C-Scan, explaining more than 50% of the warm-season temperature variance in a large area of Central Fennoscandia, agrees with the general profile of Northern Hemisphere temperature evolution during the last 12 centuries, supporting the occurrences of a Medieval Climate Anomaly (MCA) around 1009-1108 CE and a Little Ice Age (LIA) ca 1550-1900 CE in Central Fennoscandia. C-scan suggests a later onset of LIA and a larger cooling trend during 1000-1900 CE than previous MXD based reconstructions from Northern Fennoscandia. Moreover, during the last 1200 years, the coldest period was found in the late 17th-19th centuries with the coldest decades being centered on 1600 CE, and the warmest 100 years occurring in the most recent century.

  5. Can the GEOS CCM Simulate the Temperature Response to Warm Pool El Nino Events in the Antarctic Stratosphere?

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Song, I.-S.; Oman, L. D.; Newman, P. A.; Molod, A. M.; Frith, S. M.; Nielsen, J. E.

    2010-01-01

    "Warm pool" (WP) El Nino events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. During austral spring. WP El Nino events are associated with an enhancement of convective activity in the South Pacific Convergence Zone, provoking a tropospheric planetary wave response and thus increasing planetary wave driving of the Southern Hemisphere stratosphere. These conditions lead to higher polar stratospheric temperatures and to a weaker polar jet during austral summer, as compared with neutral ENSO years. Furthermore, this response is sensitive to the phase of the quasi-biennial oscillation (QBO): a stronger warming is seen in WP El Nino events coincident with the easterly phase of the quasi-biennial oscillation (QBO) as compared with WP El Nino events coincident with a westerly or neutral QBO. The Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) is used to further explore the atmospheric response to ENSO. Time-slice simulations are forced by composited SSTs from observed WP El Nino and neutral ENSO events. The modeled eddy heat flux, temperature and wind responses to WP El Nino events are compared with observations. A new gravity wave drag scheme has been implemented in the GEOS CCM, enabling the model to produce a realistic, internally generated QBO. By repeating the above time-slice simulations with this new model version, the sensitivity of the WP El Nino response to the phase of the quasi-biennial oscillation QBO is estimated.

  6. Can the GEOS CCM Simulate the Temperature Response to Warm Pool El Nino Events in the Antarctic Stratosphere?

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Song, I.-S.; Oman, L. D.; Newman, P. A.; Molod, A. M.; Frith, S. M.; Nielsen, J. E.

    2011-01-01

    "Warm pool" (WP) El Nino events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. During austral spring, WP El Nino events are associated with an enhancement of convective activity in the South Pacific Convergence Zone, provoking a tropospheric planetary wave response and thus increasing planetary wave driving of the Southern Hemisphere stratosphere. These conditions lead to higher polar stratospheric temperatures and to a weaker polar jet during austral summer, as compared with neutral ENSO years. Furthermore, this response is sensitive to the phase of the quasi-biennial oscillation (QBO): a stronger warming is seen in WP El Nino events coincident with the easterly phase of the quasi-biennial oscillation (QBO) as compared with WP El Nino events coincident with a westerly or neutral QBO. The Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) is used to further explore the atmospheric response to ENSO. Time-slice simulations are forced by composited SSTs from observed NP El Nino and neutral ENSO events. The modeled eddy heat flux, temperature and wind responses to WP El Nino events are compared with observations. A new gravity wave drag scheme has been implemented in the GEOS CCM, enabling the model to produce e realistic, internally generated QBO. By repeating the above time-slice simulations with this new model version, the sensitivity of the WP El Nino response to the phase of the quasi-biennial oscillation QBO is estimated.

  7. Regional climates in the GISS general circulation model: Surface air temperature

    NASA Technical Reports Server (NTRS)

    Hewitson, Bruce

    1994-01-01

    One of the more viable research techniques into global climate change for the purpose of understanding the consequent environmental impacts is based on the use of general circulation models (GCMs). However, GCMs are currently unable to reliably predict the regional climate change resulting from global warming, and it is at the regional scale that predictions are required for understanding human and environmental responses. Regional climates in the extratropics are in large part governed by the synoptic-scale circulation and the feasibility of using this interscale relationship is explored to provide a way of moving to grid cell and sub-grid cell scales in the model. The relationships between the daily circulation systems and surface air temperature for points across the continental United States are first developed in a quantitative form using a multivariate index based on principal components analysis (PCA) of the surface circulation. These relationships are then validated by predicting daily temperature using observed circulation and comparing the predicted values with the observed temperatures. The relationships predict surface temperature accurately over the major portion of the country in winter, and for half the country in summer. These relationships are then applied to the surface synoptic circulation of the Goddard Institute for Space Studies (GISS) GCM control run, and a set of surface grid cell temperatures are generated. These temperatures, based on the larger-scale validated circulation, may now be used with greater confidence at the regional scale. The generated temperatures are compared to those of the model and show that the model has regional errors of up to 10 C in individual grid cells.

  8. Simulation of the effect of an increase in methane on air temperature

    NASA Astrophysics Data System (ADS)

    Bi, Yun; Chen, Yuejuan; Zhou, Renjun; Yi, Mingjian; Deng, Shumei

    2011-01-01

    The infrared radiative effect of methane was analyzed using the 2D, interactive chemical dynamical radiative SOCRATES model of the National Center for Atmospheric Research. Then, a sensitivity experiment, with the methane volume mixing ratio increased by 10%, was carried out to study the influence of an increase of methane on air temperature. The results showed that methane has a heating effect through the infrared radiative process in the troposphere and a cooling effect in the stratosphere. However, the cooling effect of the methane is much smaller than that of water vapor in the stratosphere and is negligible in the mesosphere. The simulation results also showed that when methane concentration is increased by 10%, the air temperature lowers in the stratosphere and mesosphere and increases in the troposphere. The cooling can reach 0.2 K at the stratopause and can vary from 0.2-0.4 K in the mesosphere, and the temperature rise varies by around 0.001-0.002 K in the troposphere. The cooling results from the increase of the infrared radiative cooling rate caused by increased water vapor and O3 concentration, which are stimulated by the increase in methane in most of the stratosphere. The infrared radiation cooling of methane itself is minor. The depletion of O3 stimulated by the methane increase results indirectly in a decrease in the rate of solar radiation heating, producing cooling in the stratopause and mesosphere. The tropospheric warming is mainly caused by the increase of methane, which produces infrared radiative heating. The increase in H2O and O3 caused by the methane increase also contributes to a rise in temperature in the troposphere.

  9. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  10. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  11. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  12. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  13. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  14. A new approach to quantifying soil temperature responses to changing air temperature and snow cover

    NASA Astrophysics Data System (ADS)

    Mackiewicz, Michael C.

    2012-08-01

    Seasonal snow cover provides an effective insulating barrier, separating shallow soil (0.25 m) from direct localized meteorological conditions. The effectiveness of this barrier is evident in a lag in the soil temperature response to changing air temperature. The causal relationship between air and soil temperatures is largely because of the presence or absence of snow cover, and is frequently characterized using linear regression analysis. However, the magnitude of the dampening effect of snow cover on the temperature response in shallow soils is obscured in linear regressions. In this study the author used multiple linear regression (MLR) with dummy predictor variables to quantify the degree of dampening between air and shallow soil temperatures in the presence and absence of snow cover at four Greenland sites. The dummy variables defining snow cover conditions were z = 0 for the absence of snow and z = 1 for the presence of snow cover. The MLR was reduced to two simple linear equations that were analyzed relative to z = 0 and z = 1 to enable validation of the selected equations. Compared with ordinary linear regression of the datasets, the MLR analysis yielded stronger coefficients of multiple determination and less variation in the estimated regression variables.

  15. 2,000-year-long temperature and hydrology reconstructions from the Indo-Pacific warm pool.

    PubMed

    Oppo, Delia W; Rosenthal, Yair; Linsley, Braddock K

    2009-08-27

    Northern Hemisphere surface temperature reconstructions suggest that the late twentieth century was warmer than any other time during the past 500 years and possibly any time during the past 1,300 years (refs 1, 2). These temperature reconstructions are based largely on terrestrial records from extra-tropical or high-elevation sites; however, global average surface temperature changes closely follow those of the global tropics, which are 75% ocean. In particular, the tropical Indo-Pacific warm pool (IPWP) represents a major heat reservoir that both influences global atmospheric circulation and responds to remote northern high-latitude forcings. Here we present a decadally resolved continuous sea surface temperature (SST) reconstruction from the IPWP that spans the past two millennia and overlaps the instrumental record, enabling both a direct comparison of proxy data to the instrumental record and an evaluation of past changes in the context of twentieth century trends. Our record from the Makassar Strait, Indonesia, exhibits trends that are similar to a recent Northern Hemisphere temperature reconstruction. Reconstructed SST was, however, within error of modern values from about ad 1000 to ad 1250, towards the end of the Medieval Warm Period. SSTs during the Little Ice Age (approximately ad 1550-1850) were variable, and approximately 0.5 to 1 degrees C colder than modern values during the coldest intervals. A companion reconstruction of delta(18)O of sea water-a sea surface salinity and hydrology indicator-indicates a tight coupling with the East Asian monsoon system and remote control of IPWP hydrology on centennial-millennial timescales, rather than a dominant influence from local SST variation. PMID:19713927

  16. Cooling of daytime temperatures in coastal California air basins during 1969-2005: Monthly and extreme value trends

    NASA Astrophysics Data System (ADS)

    Gonzalez, J.; Bornstein, R. D.; Charland, A.; Gonzalez, J.

    2009-12-01

    Analysis of long-term (1969-2005) air temperatures in California (CA) during summer (June-August) previously showed an aggregate CA asymmetric warming, as daily minimum temperatures increased faster than daily maximum values Tmax. The spatial distributions of daily Tmax temperatures in the heavily urbanized South Coast and San Francisco Bay Area air basins were more complex pattern, with cooling at low-elevation coastal-areas and warming at inland areas. Our hypothesis was that this temperature pattern arose from a “reverse-reaction” to greenhouse gas induced global-warming, in that the global warming of inland areas resulted in an increased (cooling) sea breeze activity in coastal areas. These results appeared in the July 2009 issue of the J. of Climate. Extension of this analysis over the entire year now shows that the cooling trend in average Tmax values occurred during most months, with warming trends only during winter months. The largest rate of cooling, however, occurred in June (-0.95 K/decade), indicating that an earlier initiation of sea breeze activity may be the most important cooling factor, relative to increases in its intensity, duration, and/or penetration. Possible beneficial effects of the cooling were discussed (e.g., decreased maximum O3 and human thermal-stress levels), but as these impact would occur during periods of maximum Tmax values, the previous analysis was thus expanded to includes trends in the frequency of high Tmax values, i.e., 85, 90, 95, and 100oF. Results showed that all of these frequencies were decreasing, with rates decreasing with Tmax value (from -0.27 to -0.04 days/year, respectively). While this result is expected, as the frequency of occurrence decreases with Tmax value (from about 50 to about 3 per year, respectively), the percent decrease in frequency showed the opposite results, i.e., it was largest with the highest Tmax value (from -0.57 to -1.57 %/year, respectively). In addition, the rate of decrease of annual

  17. Temperature responses of tropical to warm temperate Cladophora species in relation to their distribution in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Cambridge, M. L.; Breeman, A. M.; Kraak, S.; van den Hoek, C.

    1987-09-01

    The relationship between distribution boundaries and temperature responses of some North Atlantic Cladophora species (Chlorophyta) was experimentally examined under various regimes of temperature, light and daylength. Experimentally determined critical temperature intervals, in which survival, growth or reproduction was limited, were compared with annual temperature regimes (monthly means and extremes) at sites inside and outside distribution boundaries. The species tested belonged to two phytogeographic groups: (1) the tropical West Atlantic group ( C. submarina: isolate from Curaçao) and (2) the amphiatlantic tropical to warm temperate group ( C. prolifera: isolate from Corsica; C. coelothrix: isolates from Brittany and Curaçao; and C. laetevirens: isolates from deep and shallow water in Corsica and from Brittany). In accordance with distribution from tropical to warm temperate regions, each of the species grew well between 20 30°C and reproduction and growth were limited at and below 15°C. The upper survival limit in long days was <35°C in all species but high or maximum growth rates occurred at 30°C. C. prolifera, restricted to the tropical margins, had the most limited survival at 35°C. Experimental evidence suggests that C. submarina is restricted to the Caribbean and excluded from the more northerly American mainland and Gulf of Mexico coasts by sporadic low winter temperatures in the nearshore waters, when cold northerly weather penetrates far south every few years. Experimental evidence suggests that C. prolifera, C. coelothrix and C. laetevirens are restricted to their northern European boundaries by summer temperatures too low for sufficient growth and/or reproduction. Their progressively more northerly located boundaries were accounted for by differences in growth rates over the critical 10 15°C interval. C. prolifera and C. coelothrix are excluded or restricted in distribution on North Sea coasts by lethal winter temperatures, again differences

  18. Change point analysis of mean annual air temperature in Iran

    NASA Astrophysics Data System (ADS)

    Shirvani, A.

    2015-06-01

    The existence of change point in the mean of air temperature is an important indicator of climate change. In this study, Student's t parametric and Mann-Whitney nonparametric Change Point Models (CPMs) were applied to test whether a change point has occurred in the mean of annual Air Temperature Anomalies Time Series (ATATS) of 27 synoptic stations in different regions of Iran for the period 1956-2010. The Likelihood Ratio Test (LRT) was also applied to evaluate the detected change points. The ATATS of all stations except Bandar Anzali and Gorgan stations, which were serially correlated, were transformed to produce an uncorrelated pre-whitened time series as an input file for the CPMs and LRT. Both the Student's t and Mann-Whitney CPMs detected the change point in the ATATS of (a) Tehran Mehrabad, Abadan, Kermanshah, Khoramabad and Yazd in 1992, (b) Mashhad and Tabriz in 1993, (c) Bandar Anzali, Babolsar and Ramsar in 1994, (d) Kerman and Zahedan in 1996 at 5% significance level. The likelihood ratio test shows that the ATATS before and after detected change points in these 12 stations are normally distributed with different means. The Student's t and Mann-Whitney CPMs suggested different change points for individual stations in Bushehr, Bam, Shahroud, and Gorgan. However, the LRT confirmed the change points in these four stations as 1997, 1996, 1993, and 1996, respectively. No change points were detected in the remaining 11 stations.

  19. Solubility of polyethers in hydrocarbons at low temperatures. A model for potential genetic backbones on warm titans.

    PubMed

    McLendon, Christopher; Opalko, F Jeffrey; Illangkoon, Heshan I; Benner, Steven A

    2015-03-01

    Ethers are proposed here as the repeating backbone linking units in linear genetic biopolymers that might support Darwinian evolution in hydrocarbon oceans. Hydrocarbon oceans are found in our own solar system as methane mixtures on Titan. They may be found as mixtures of higher alkanes (propane, for example) on warmer hydrocarbon-rich planets in exosolar systems ("warm Titans"). We report studies on the solubility of several short polyethers in propane over its liquid range (from 85 to 231 K, or -188 °C to -42 °C). These show that polyethers are reasonably soluble in propane at temperatures down to ca. 200 K. However, their solubilities drop dramatically at still lower temperatures and become immeasurably low below 170 K, still well above the ∼ 95 K in Titan's oceans. Assuming that a liquid phase is essential for any living system, and genetic biopolymers must dissolve in that biosolvent to support Darwinism, these data suggest that we must look elsewhere to identify linear biopolymers that might support genetics in Titan's surface oceans. However, genetic molecules with polyether backbones may be suitable to support life in hydrocarbon oceans on warm Titans, where abundant organics and environments lacking corrosive water might make it easier for life to originate. PMID:25761113

  20. Effect of Ambient Design Temperature on Air-Cooled Binary Plant Output

    SciTech Connect

    Dan Wendt; Greg Mines

    2011-10-01

    Air-cooled binary plants are designed to provide a specified level of power production at a particular air temperature. Nominally this air temperature is the annual mean or average air temperature for the plant location. This study investigates the effect that changing the design air temperature has on power generation for an air-cooled binary plant producing power from a resource with a declining production fluid temperature and fluctuating ambient temperatures. This analysis was performed for plants operating both with and without a geothermal fluid outlet temperature limit. Aspen Plus process simulation software was used to develop optimal air-cooled binary plant designs for specific ambient temperatures as well as to rate the performance of the plant designs at off-design operating conditions. Results include calculation of annual and plant lifetime power generation as well as evaluation of plant operating characteristics, such as improved power generation capabilities during summer months when electric power prices are at peak levels.

  1. Assessing surface air temperature variability using quantile regression

    NASA Astrophysics Data System (ADS)

    Timofeev, A. A.; Sterin, A. M.

    2014-12-01

    Many researches in climate change currently involve linear trends, based on measured variables. And many of them only consider trends in mean values, whereas it is clear, that not only means, but also whole shape of distribution changes over time and requires careful assessment. For example extreme values including outliers may get bigger, while median has zero slope.Quantile regression provides a convenient tool, that enables detailed analysis of changes in full range of distribution by producing a vector of quantile trends for any given set of quantiles.We have applied quantile regression to surface air temperature observations made at over 600 weather stations across Russian Federation during last four decades. The results demonstrate well pronounced regions with similar values of significant trends in different parts of temperature value distribution (left tail, middle part, right tail). The uncertainties of quantile trend estimations for several spatial patterns of trends over Russia are estimated and analyzed for each of four seasons.For temperature trend estimation over vast territories, quantile regression is an effort consuming approach, but is more informative than traditional instrument, to assess decadal evolution of temperature values, including evolution of extremes.Partial support of ERA NET RUS ACPCA joint project between EU and RBRF 12-05-91656-ЭРА-А is highly appreciated.

  2. Ambient Temperature Influences Australian Native Stingless Bee (Trigona carbonaria) Preference for Warm Nectar

    PubMed Central

    Norgate, Melanie; Boyd-Gerny, Skye; Simonov, Vera; Rosa, Marcello G. P.; Heard, Tim A.; Dyer, Adrian G.

    2010-01-01

    The interaction between flowers and insect pollinators is an important aspect of the reproductive mechanisms of many plant species. Several laboratory and field studies indicate that raising flower temperature above ambient can be an advantage in attracting pollinators. Here we demonstrate that this preference for warmer flowers is, in fact, context-dependent. Using an Australian native bee as a model, we demonstrate for the first time a significant shift in behaviour when the ambient temperature reaches 34°C, at which point bees prefer ambient temperature nectar over warmer nectar. We then use thermal imaging techniques to show warmer nectar maintains the flight temperature of bees during the period of rest on flowers at lower ambient temperatures but the behavioural switch is associated with the body temperature rising above that maintained during flight. These findings suggest that flower-pollinator interactions are dependent upon ambient temperature and may therefore alter in different thermal environments. PMID:20711250

  3. The Impact of “Unseasonably” Warm Spring Temperatures on Acute Myocardial Infarction Hospital Admissions in Melbourne, Australia: A City with a Temperate Climate

    PubMed Central

    Tapper, Nigel; Loughnan, Terence

    2014-01-01

    The effects of extreme temperatures on human health have been well described. However, the adverse health effects of warm weather that occurs outside the summer period have had little attention. We used daily anomalous AMI morbidity and daily anomalous temperature to determine the impact of “unseasonable” temperature on human health. The “unseasonably” warm weather was attributed to a slow moving high pressure system to the east of Melbourne. No morbidity displacement was noted during either of these periods suggesting that morbidity due to “unseasonable” temperatures is avoidable. An increase in warmer weather during the cooler months of spring may result in increased morbidity, and an alert system based on summer thresholds may not be appropriate for early season heat health warnings. A straightforward alert system based on calculating anomalous temperature from daily weather forecasts may reduce the public health impact of “unseasonably” warm weather. PMID:25002870

  4. A slightly more massive young Sun as an explanation for warm temperatures on early Mars

    NASA Technical Reports Server (NTRS)

    Whitmire, Daniel P.; Doyle, Laurance R.; Reynolds, Ray T.; Matese, John J.

    1995-01-01

    The valley network channels on the heavily cratered ancient surface of Mars suggest the presence of liquid water approximately 3.8 Gyr ago. However, the implied warm climate is difficult to explain in the context of the standard solar model, even allowing for the maximum CO2 greenhouse heating. In this paper we investigate the astronomical and planetary implications of a nonstandard solar model in which the zero-age, main-sequence Sun had a mass of 1.05 +/- 0.02 Solar Mass. The excess mass was subsequently lost in a solar wind during the first 1.2(-0.2, +0.4) Gyr of the Sun's main sequence phase. The implied mass-loss rate of 4(+3, -2) x 10(exp -11) M/yr, or about 10(exp 3) x that of the current Sun, may be detectable in several nearby young solar type stars.

  5. A slightly more massive young Sun as an explanation for warm temperatures on early Mars

    NASA Technical Reports Server (NTRS)

    Whitmire, Daniel P.; Doyle, Laurance R.; Reynolds, Ray T.; Matese, John J.

    1995-01-01

    The valley network channels on the heavily cratered ancient surface of Mars suggest the presence of liquid water approx. 3.8 Gyr ago. However, the implied warm climate is difficult to explain in the context of the standard solar model, even allowing for the maximum CO2 greenhouse heating. In this paper we investigate the astronomical and planetary implications of a nonstandard solar model in which the zero-age, main-sequence Sun had a mass of 1.05 +/- 0.02 Solar Mass. The excess mass was subsequently lost in a solar wind during the first 1.2(sup -0.2)(sub +.04) Gyr of the Sun's main sequence phase. The implied mass-loss rate of 4(sup +3)(sub -2) x 10(exp -11) Solar Mass/yr, or about 10(exp 3) times that of the current Sun, may be detectable in several nearby young solar type stars.

  6. EXCITATION TEMPERATURE OF THE WARM NEUTRAL MEDIUM AS A NEW PROBE OF THE Lyα RADIATION FIELD

    SciTech Connect

    Murray, Claire E.; Lindner, Robert R.; Stanimirović, Snežana; Pingel, Nickolas M.; Lawrence, Allen; Babler, Brian L.; Goss, W. M.; Jencson, Jacob; Heiles, Carl; Dickey, John; Hennebelle, Patrick

    2014-02-01

    We use the Karl G. Jansky Very Large Array to conduct a high-sensitivity survey of neutral hydrogen (H I) absorption in the Milky Way. In combination with corresponding H I emission spectra obtained mostly with the Arecibo Observatory, we detect a widespread warm neutral medium component with excitation temperature 〈T{sub s}〉=7200{sub −1200}{sup +1800} K (68% confidence). This temperature lies above theoretical predictions based on collisional excitation alone, implying that Lyα scattering, the most probable additional source of excitation, is more important in the interstellar medium (ISM) than previously assumed. Our results demonstrate that H I absorption can be used to constrain the Lyα radiation field, a critical quantity for studying the energy balance in the ISM and intergalactic medium yet notoriously difficult to model because of its complicated radiative transfer, in and around galaxies nearby and at high redshift.

  7. Recrystallization kinetics of warm-rolled tungsten in the temperature range 1150-1350 °C

    NASA Astrophysics Data System (ADS)

    Alfonso, A.; Juul Jensen, D.; Luo, G.-N.; Pantleon, W.

    2014-12-01

    Pure tungsten is a potential candidate material for the plasma-facing first wall and the divertor of fusion reactors. Both parts have to withstand high temperatures during service. This will alter the microstructure of the material by recovery, recrystallization and grain growth and will cause degradation in material properties as a loss in mechanical strength and embrittlement. The thermal stability of a pure tungsten plate warm-rolled to 67% thickness reduction was investigated by long-term isothermal annealing in the temperature range between 1150 °C and 1350 °C up to 2200 h. Changes in the mechanical properties during annealing are quantified by Vickers hardness measurements. They are described concisely by classical kinetic models for recovery and recrystallization. The observed time spans for recrystallization and the obtained value for the activation energy of the recrystallization process indicate a sufficient thermal stability of the tungsten plate during operation below 1075 °C.

  8. Warm Is Better: Incubation Temperature Influences Apparent Survival and Recruitment of Wood Ducks (Aix sponsa)

    PubMed Central

    Hepp, Gary R.; Kennamer, Robert A.

    2012-01-01

    Avian parents that physically incubate their eggs must balance demands of self-maintenance with providing the proper thermal environment for egg development. Low incubation temperatures can lengthen the incubation period and produce changes in neonate phenotype that may influence subsequent survival and reproduction. We artificially incubated wood duck (Aix sponsa) eggs at three temperature regimes (low, 35.0; mid, 35.9; and high, 37.3°C) that are within the range of temperatures of naturally-incubated nests. We tested the effect of incubation temperature on duckling body composition, fledging success, the probability that females were recruited to the breeding population, and their subsequent reproductive success. Incubation period was inversely related to incubation temperature, and body mass and lipid mass for newly-hatched ducklings incubated at the lowest temperature were lower than for ducklings produced at higher temperatures. In 2008, ducklings (n = 412) were individually marked and broods (n = 38) containing ducklings from each temperature treatment were placed with wild foster mothers within 24 hrs of hatching. Ducklings incubated at the lowest temperature were less likely to fledge from nest sites than ducklings incubated at the higher temperatures. We recaptured female ducklings as adults when they were either prospecting for nest sites (n = 171; 2009–2011) or nesting (n = 527; 2009–2012). Female ducklings incubated at the lowest temperature were less likely to survive and be recruited to the breeding population than females incubated at higher temperatures. Reproductive success of surviving females also was greater for females that had been incubated at warmer temperatures. To our knowledge, this is the first avian study to link developmental conditions experienced by neonates during incubation with their survival and recruitment to the breeding population, and subsequent reproductive success. These results advance our

  9. Air Surface Temperature Correlation with Greenhouse Gases by Using Airs Data Over Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim Mohammed; MatJafri, M. Z.; Lim, H. S.

    2014-08-01

    The main objective of this study is to develop algorithms for calculating the air surface temperature (AST). This study also aims to analyze and investigate the effects of greenhouse gases (GHGs) on the AST value in Peninsular Malaysia. Multiple linear regression is used to achieve the objectives of the study. Peninsular Malaysia has been selected as the research area because it is among the regions of tropical Southeast Asia with the greatest humidity, pockets of heavy pollution, rapid economic growth, and industrialization. The predicted AST was highly correlated ( R = 0.783) with GHGs for the 6-year data (2003-2008). Comparisons of five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the wet season (within 1.3 K). The in situ data ranged from 1 to 2 K. Validation results showed that AST ( R = 0.776-0.878) has values nearly the same as the observed AST from AIRS. We found that O3 during the wet season was indicated by a strongly positive beta coefficient (0.264-0.992) with AST. The CO2 yields a reasonable relationship with temperature with low to moderate beta coefficient (-0.065 to 0.238). The O3, CO2, and environmental variables experienced different seasonal fluctuations that depend on weather conditions and topography. The concentration of gases and pollution were the highest over industrial zones and overcrowded cities, and the dry season was more polluted compared with the wet season. These results indicate the advantage of using the satellite AIRS data and a correlation analysis to investigate the effect of atmospheric GHGs on AST over Peninsular Malaysia. An algorithm that is capable of retrieving Peninsular Malaysian AST in all weather conditions with total uncertainties ranging from 1 to 2 K was developed.

  10. Trends and abrupt changes in 104 years of ice cover and water temperature in a dimictic lake in response to air temperature, wind speed, and water clarity drivers

    NASA Astrophysics Data System (ADS)

    Magee, Madeline R.; Wu, Chin H.; Robertson, Dale M.; Lathrop, Richard C.; Hamilton, David P.

    2016-05-01

    The one-dimensional hydrodynamic ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, Wisconsin, USA, over a continuous 104-year period (1911-2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multiyear timescales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s-1 before 1994 to 3.74 m s-1 thereafter. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice-on date(9.0 days later per century), earlier ice-off date (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (-1.4 °C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911-1980, 1981-1993, and 1994-2014) delineated by

  11. Impact of Air Temperature and SST Variability on Cholera Incidence in Southeastern Africa, 1971-2006

    NASA Astrophysics Data System (ADS)

    Paz, Shlomit

    2010-05-01

    The most important climatic parameter related to cholera outbreaks is the temperature, especially of the water bodies and the aquatic environment. This factor governs the survival and growth of V. cholerae, since it has a direct influence on its abundance in the environment, or alternatively, through its indirect influence on other aquatic organisms to which the pathogen is found to attach. Thus, the potential for cholera outbreaks may rise, parallel to the increase in ocean surface temperature. Indeed, recent studies indicate that global warming might create a favorable environment for V. cholerae and increase its incidence in vulnerable areas. Africa is vulnerable to climate variability. According to the recent IPCC report on Africa, the air temperature has indicated a significant warming trend since the 1960s. In recent years, most of the research into disease vectors in Africa related to climate variability has focused on malaria. The IPCC indicated that the need exists to examine the vulnerabilities and impacts of climatic factors on cholera in Africa. In light of this, the study uses a Poisson Regression Model to analyze the possible association between the cholera rates in southeastern Africa and the annual variability of air temperature and sea surface temperature (SST) at regional and hemispheric scales, for the period 1971-2006. Data description is as follows: Number of cholera cases per year in Uganda, Kenya, Rwanda, Burundi, Tanzania, Malawi, Zambia and Mozambique. Source: WHO Global Health Atlas - cholera. Seasonal and annual temperature time series: Regional scale: a) Air temperature for southeastern Africa (30° E-36° E, 5° S-17° S), source: NOAA NCEP-NCAR; b) Sea surface temperature, for the western Indian Ocean (0-20° S, 40° E-45° E), source: NOAA, Kaplan SST dataset. Hemispheric scale (for the whole Southern Hemisphere): a) Air temperature anomaly; b) Sea surface temperature anomaly. Source: CRU, University of East Anglia. The following

  12. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    PubMed

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). PMID:25640748

  13. Cyclic Oxidation of High-Temperature Alloy Wires in Air

    NASA Technical Reports Server (NTRS)

    Reigel, Marissa M.

    2004-01-01

    High-temperature alloy wires are proposed for use in seal applications for future re-useable space vehicles. These alloys offer the potential for improved wear resistance of the seals. The wires must withstand the high temperature environments the seals are subjected to as well as maintain their oxidation resistance during the heating and cooling cycles of vehicle re-entry. To model this, the wires were subjected to cyclic oxidation in stagnant air. of this layer formation is dependent on temperature. Slow growing oxides such as chromia and alumina are desirable. Once the oxide is formed it can prevent the metal from further reacting with its environment. Cyclic oxidation models the changes in temperature these wires will undergo in application. Cycling the temperature introduces thermal stresses which can cause the oxide layer to break off. Re-growth of the oxide layer consumes more metal and therefore reduces the properties and durability of the material. were used for cyclic oxidation testing. The baseline material, Haynes 188, has a Co base and is a chromia former while the other two alloys, Kanthal A1 and PM2000, both have a Fe base and are alumina formers. Haynes 188 and Kanthal A1 wires are 250 pm in diameter and PM2000 wires are 150 pm in diameter. The coiled wire has a total surface area of 3 to 5 sq cm. The wires were oxidized for 11 cycles at 1204 C, each cycle containing a 1 hour heating time and a minimum 20 minute cooling time. Weights were taken between cycles. After 11 cycles, one wire of each composition was removed for analysis. The other wire continued testing for 70 cycles. Post-test analysis includes X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) for phase identification and morphology.

  14. Negative impacts of high temperatures on growth of black spruce forests intensify with the anticipated climate warming.

    PubMed

    Girardin, Martin P; Hogg, Edward H; Bernier, Pierre Y; Kurz, Werner A; Guo, Xiao Jing; Cyr, Guillaume

    2016-02-01

    An increasing number of studies conclude that water limitations and heat stress may hinder the capacity of black spruce (Picea mariana (Mill.) B.S.P.) trees, a dominant species of Canada's boreal forests, to grow and assimilate atmospheric carbon. However, there is currently no scientific consensus on the future of these forests over the next century in the context of widespread climate warming. The large spatial extent of black spruce forests across the Canadian boreal forest and associated variability in climate, demography, and site conditions pose challenges for projecting future climate change responses. Here we provide an evaluation of the impacts of climate warming and drying, as well as increasing [CO2 ], on the aboveground productivity of black spruce forests across Canada south of 60°N for the period 1971 to 2100. We use a new extensive network of tree-ring data obtained from Canada's National Forest Inventory, spatially explicit simulations of net primary productivity (NPP) and its drivers, and multivariate statistical modeling. We found that soil water availability is a significant driver of black spruce interannual variability in productivity across broad areas of the western to eastern Canadian boreal forest. Interannual variability in productivity was also found to be driven by autotrophic respiration in the warmest regions. In most regions, the impacts of soil water availability and respiration on interannual variability in productivity occurred during the phase of carbohydrate accumulation the year preceding tree-ring formation. Results from projections suggest an increase in the importance of soil water availability and respiration as limiting factors on NPP over the next century due to warming, but this response may vary to the extent that other factors such as carbon dioxide fertilization, and respiration acclimation to high temperature, contribute to dampening these limitations. PMID:26507106

  15. Negative impacts of high temperatures on growth of black spruce forests intensify with the anticipated climate warming

    NASA Astrophysics Data System (ADS)

    Girardin, M. P.; Hogg, T.; Kurz, W.; Bernier, P. Y.; Guo, X. J.; Cyr, G.

    2015-12-01

    An increasing number of studies conclude that water limitations and heat stress may hinder the capacity of black spruce (Picea mariana (Mill.) B.S.P.) trees, a dominant species of Canada's boreal forests, to grow and assimilate atmospheric carbon. However, there is currently no scientific consensus on the future of these forests over the next century in the context of widespread climate warming. The large spatial extent of black spruce forests across the Canadian boreal forest and associated variability in climate, demography and site conditions pose challenges for projecting future climate change responses. Here we provide an evaluation of the impacts of climate warming and drying, as well as increasing [CO2], on the aboveground productivity of black spruce forests across Canada south of 60ºN for the period 1971 to 2100. We use a new extensive network of tree-ring data obtained from Canada's National Forest Inventory, spatially-explicit simulations of Net Primary Productivity (NPP) and its drivers, and multivariate statistical modelling. We found that soil water availability is a significant driver of black spruce inter-annual variability in productivity across broad areas of the western to eastern Canadian boreal forest. Inter-annual variability in productivity was also found to be driven by autotrophic respiration in the warmest regions. In most regions, the impacts of soil water availability and respiration on inter-annual variability in productivity occurred during the phase of carbohydrate accumulation the year preceding tree ring formation. Results from projections suggest an increase in the importance of soil water availability and respiration as limiting factors on NPP over the next century due to warming, but this response may vary to the extent that other factors such as carbon dioxide fertilization, and respiration acclimation to high temperature, contribute to dampening these limitations.

  16. Climate: large-scale warming is not urban.

    PubMed

    Parker, David E

    2004-11-18

    Controversy has persisted over the influence of urban warming on reported large-scale surface-air temperature trends. Urban heat islands occur mainly at night and are reduced in windy conditions. Here we show that, globally, temperatures over land have risen as much on windy nights as on calm nights, indicating that the observed overall warming is not a consequence of urban development. PMID:15549087

  17. Variations in air and ground temperature and the POM-SAT model: results from the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Harris, R. N.

    2007-10-01

    The POM-SAT model for comparing air and ground temperatures is based on the supposition that surface air temperature (SAT) records provide a good prediction of thermal transients in the shallow subsurface of the Earth. This model consists of two components, the forcing function and an initial condition, termed the pre-observational mean (POM). I explore the sensitivity of this model as a function of forcing periods at time scales appropriate for climate reconstructions. Synthetic models are designed to replicate comparisons between borehole temperatures contained in the global database of temperature profiles for climate reconstructions and gridded SAT data. I find that the root mean square (RMS) misfit between forcing functions and transient temperature profiles in the subsurface are sensitive to periods longer than about 50 years, are a maximum when the period and the 150-year time series are equal and then decreases for longer periods. The magnitude of the POM is a robust parameter for periods equal to or shorter than the length of this time series. At longer periods there is a tradeoff between the amplitude of the forcing function and the POM. These tests provide guidelines for assessing comparisons between air and ground temperatures at periods appropriate for climate reconstructions. The sensitivity of comparisons between the average Northern Hemisphere gridded SAT record and subsurface temperature-depth profile as a function of forcing period is assessed. This analysis indicates that the Northern Hemisphere extratropical average SAT and reduced temperature-depth profile are in good agreement. By adding modest heat to the subsurface at intermediate periods some improvement in misfit can be made, but this extra heat has negligible influence on the POM. The joint analysis of borehole temperatures and SAT records indicate warming of about 1.1°C over the last 500 years, consistent with previous studies.

  18. Study of Ram-air Heat Exchangers for Reducing Turbine Cooling-air Temperature of a Supersonic Aircraft Turbojet Engine

    NASA Technical Reports Server (NTRS)

    Diaguila, Anthony J; Livingood, John N B; Eckert, Ernst R G

    1956-01-01

    The sizes and weights of the cores of heat exchangers were determined analytically for possible application for reducing turbine cooling-air temperatures of an engine designed for a Mach number of 2.5 and an altitude The sizes and weights of the cores of heat exchangers were determined analytically for possible application for reducing turbine cooling-air temperatures of an engine designed for a Mach number of 2.5 and an altitude of 70,000 feet. A compressor-bleed-air weight flow of 2.7 pounds per second was assumed for the coolant; ram air was considered as the other fluid. Pressure drops and inlet states of both fluids were prescribed, and ranges of compressor-bleed-air temperature reductions and of the ratio of compressor-bleed to ram-air weight flows were considered.

  19. Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction.

    PubMed

    García-Robledo, Carlos; Kuprewicz, Erin K; Staines, Charles L; Erwin, Terry L; Kress, W John

    2016-01-19

    The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming. PMID:26729867

  20. Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction

    PubMed Central

    García-Robledo, Carlos; Kuprewicz, Erin K.; Staines, Charles L.; Erwin, Terry L.; Kress, W. John

    2016-01-01

    The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming. PMID:26729867

  1. An improved model for soil surface temperature from air temperature in permafrost regions of Qinghai-Xizang (Tibet) Plateau of China

    NASA Astrophysics Data System (ADS)

    Hu, Guojie; Wu, Xiaodong; Zhao, Lin; Li, Ren; Wu, Tonghua; Xie, Changwei; Pang, Qiangqiang; Cheng, Guodong

    2016-06-01

    Soil temperature plays a key role in hydro-thermal processes in environments and is a critical variable linking surface structure to soil processes. There is a need for more accurate temperature simulation models, particularly in Qinghai-Xizang (Tibet) Plateau (QXP). In this study, a model was developed for the simulation of hourly soil surface temperatures with air temperatures. The model incorporated the thermal properties of the soil, vegetation cover, solar radiation, and water flux density and utilized field data collected from Qinghai-Xizang (Tibet) Plateau (QXP). The model was used to simulate the thermal regime at soil depths of 5 cm, 10 cm and 20 cm and results were compared with those from previous models and with experimental measurements of ground temperature at two different locations. The analysis showed that the newly developed model provided better estimates of observed field temperatures, with an average mean absolute error (MAE), root mean square error (RMSE), and the normalized standard error (NSEE) of 1.17 °C, 1.30 °C and 13.84 %, 0.41 °C, 0.49 °C and 5.45 %, 0.13 °C, 0.18 °C and 2.23 % at 5 cm, 10 cm and 20 cm depths, respectively. These findings provide a useful reference for simulating soil temperature and may be incorporated into other ecosystem models requiring soil temperature as an input variable for modeling permafrost changes under global warming.

  2. Warm spring temperatures induce persistent season-long changes in shoot development in grapevines

    PubMed Central

    Keller, Markus; Tarara, Julie M.

    2010-01-01

    Background and Aims The influence of temperature on the timing of budbreak in woody perennials is well known, but its effect on subsequent shoot growth and architecture has received little attention because it is understood that growth is determined by current temperature. Seasonal shoot development of grapevines (Vitis vinifera) was evaluated following differences in temperature near budbreak while minimizing the effects of other microclimatic variables. Methods Dormant buds and emerging shoots of field-grown grapevines were heated above or cooled below the temperature of ambient buds from before budbreak until individual flowers were visible on inflorescences, at which stage the shoots had four to eight unfolded leaves. Multiple treatments were imposed randomly on individual plants and replicated across plants. Shoot growth and development were monitored during two growing seasons. Key Results Higher bud temperatures advanced the date of budbreak and accelerated shoot growth and leaf area development. Differences were due to higher rates of shoot elongation, leaf appearance, leaf-area expansion and axillary-bud outgrowth. Although shoots arising from heated buds grew most vigorously, apical dominance in these shoots was reduced, as their axillary buds broke earlier and gave rise to more vigorous lateral shoots. In contrast, axillary-bud outgrowth was minimal on the slow-growing shoots emerging from buds cooled below ambient. Variation in shoot development persisted or increased during the growing season, well after temperature treatments were terminated and despite an imposed soil water deficit. Conclusions The data indicate that bud-level differences in budbreak temperature may lead to marked differences in shoot growth, shoot architecture and leaf-area development that are maintained or amplified during the growing season. Although growth rates commonly are understood to reflect current temperatures, these results demonstrate a persistent effect of early

  3. Single Cell Transcriptomics of Hypothalamic Warm Sensitive Neurons that Control Core Body Temperature and Fever Response

    PubMed Central

    Eberwine, James; Bartfai, Tamas

    2011-01-01

    We report on an ‘unbiased’ molecular characterization of individual, adult neurons, active in a central, anterior hypothalamic neuronal circuit, by establishing cDNA libraries from each individual, electrophysiologically identified warm sensitive neuron (WSN). The cDNA libraries were analyzed by Affymetrix microarray. The presence and frequency of cDNAs was confirmed and enhanced with Illumina sequencing of each single cell cDNA library. cDNAs encoding the GABA biosynthetic enzyme. GAD1 and of adrenomedullin, galanin, prodynorphin, somatostatin, and tachykinin were found in the WSNs. The functional cellular and in vivo studies on dozens of the more than 500 neurotransmitter -, hormone- receptors and ion channels, whose cDNA was identified and sequence confirmed, suggest little or no discrepancy between the transcriptional and functional data in WSNs; whenever agonists were available for a receptor whose cDNA was identified, a functional response was found.. Sequencing single neuron libraries permitted identification of rarely expressed receptors like the insulin receptor, adiponectin receptor2 and of receptor heterodimers; information that is lost when pooling cells leads to dilution of signals and mixing signals. Despite the common electrophysiological phenotype and uniform GAD1 expression, WSN- transcriptomes show heterogenity, suggesting strong epigenetic influence on the transcriptome. Our study suggests that it is well-worth interrogating the cDNA libraries of single neurons by sequencing and chipping. PMID:20970451

  4. Impacts of wind farms on surface air temperatures

    PubMed Central

    Baidya Roy, Somnath; Traiteur, Justin J.

    2010-01-01

    Utility-scale large wind farms are rapidly growing in size and numbers all over the world. Data from a meteorological field campaign show that such wind farms can significantly affect near-surface air temperatures. These effects result from enhanced vertical mixing due to turbulence generated by wind turbine rotors. The impacts of wind farms on local weather can be minimized by changing rotor design or by siting wind farms in regions with high natural turbulence. Using a 25-y-long climate dataset, we identified such regions in the world. Many of these regions, such as the Midwest and Great Plains in the United States, are also rich in wind resources, making them ideal candidates for low-impact wind farms. PMID:20921371

  5. Subseasonal variability of North American wintertime surface air temperature

    NASA Astrophysics Data System (ADS)

    Lin, Hai

    2015-09-01

    Using observational pentad data of the recent 34 Northern Hemisphere extended winters, subseasonal variability of surface air temperature (SAT) over North America is analyzed. The four leading modes of subseasonal SAT variability, that are identified with an empirical orthogonal function (EOF) analysis, account for about 60% of the total variance. The first (EOF1) and second (EOF2) modes are independent of other modes, and thus are likely controlled by distinct processes. The third (EOF3) and fourth (EOF4) modes, however, tend to have a phase shift to each other in space and time, indicating that part of their variability is related to a common process and represent a propagating pattern over North America. Lagged regression analysis is conducted to identify the precursors of large-scale atmospheric circulation for each mode a few pentads in advance, and to understand the processes that influence the subseasonal SAT variability and the predictability signal sources. EOF1 is found to be closely related to the Pacific-North American (PNA) circulation pattern and at least part of its variability is preceded by the East Asian cold surge. The cold surge leads to low-level convergence and enhanced convection in the tropical central Pacific which in turn induces the PNA. EOF2 tends to oscillate at a period of about 70 days, and is influenced by the low-frequency component of the Madden-Julian Oscillation (MJO). On the other hand, EOF3 and EOF4 are connected to the high-frequency part of the MJO which has a period range of 30-50 days. These findings would help understanding the mechanisms of subseasonal surface air temperature variability in North America and improving weather predictions on a subseasonal time scale.

  6. Temperature dynamics and velocity scaling laws for interchange driven, warm ion plasma filaments

    NASA Astrophysics Data System (ADS)

    Olsen, Jeppe; Madsen, Jens; Nielsen, Anders Henry; Rasmussen, Jens Juul; Naulin, Volker

    2016-04-01

    The influence of electron and ion temperature dynamics on the radial convection of isolated structures in magnetically confined plasmas is investigated by means of numerical simulations. It is demonstrated that the maximum radial velocity of these plasma blobs roughly follows the inertial velocity scaling, which is proportional to the ion acoustic speed times the square root of the filament particle density times the sum of the electron and ion temperature perturbations. Only for small blobs the cross field convection does not follow this scaling. The influence of finite Larmor radius effects on the cross-field blob convection is shown not to depend strongly on the dynamical ion temperature field. The blob dynamics of constant finite and dynamical ion temperature blobs is similar. When the blob size is on the order of 10 times the ion Larmor radius the blobs stay coherent and decelerate slowly compared to larger blobs which dissipate faster due to fragmentation and turbulent mixing.

  7. Increased temperature variation poses a greater risk to species than climate warming.

    PubMed

    Vasseur, David A; DeLong, John P; Gilbert, Benjamin; Greig, Hamish S; Harley, Christopher D G; McCann, Kevin S; Savage, Van; Tunney, Tyler D; O'Connor, Mary I

    2014-03-22

    Increases in the frequency, severity and duration of temperature extremes are anticipated in the near future. Although recent work suggests that changes in temperature variation will have disproportionately greater effects on species than changes to the mean, much of climate change research in ecology has focused on the impacts of mean temperature change. Here, we couple fine-grained climate projections (2050-2059) to thermal performance data from 38 ectothermic invertebrate species and contrast projections with those of a simple model. We show that projections based on mean temperature change alone differ substantially from those incorporating changes to the variation, and to the mean and variation in concert. Although most species show increases in performance at greater mean temperatures, the effect of mean and variance change together yields a range of responses, with temperate species at greatest risk of performance declines. Our work highlights the importance of using fine-grained temporal data to incorporate the full extent of temperature variation when assessing and projecting performance. PMID:24478296

  8. Food restriction attenuates oxidative stress in brown adipose tissue of striped hamsters acclimated to a warm temperature.

    PubMed

    Zhang, Ji-Ying; Zhao, Xiao-Ya; Wang, Gui-Ying; Wang, Chun-Ming; Zhao, Zhi-Jun

    2016-05-01

    It has been suggested that the up-regulation of uncoupling proteins (UCPs) decreases reactive oxygen species (ROS) production, in which case there should be a negative relationship between UCPs expression and ROS levels. In this study, the effects of temperature and food restriction on ROS levels and metabolic rate, UCP1 mRNA expression and antioxidant levels were examined in the brown adipose tissue (BAT) of the striped hamsters (Cricetulus barabensis). The metabolic rate and food intake of hamsters which had been restricted to 80% of ad libitum food intake, and acclimated to a warm temperature (30°C), decreased significantly compared to a control group. Hydrogen peroxide (H2O2) levels were 42.9% lower in food restricted hamsters than in the control. Malonadialdehyde (MDA) levels of hamsters acclimated to 30°C that were fed ad libitum were significantly higher than those of the control group, but 60.1% lower than hamsters that had been acclimated to the same temperature but subject to food restriction. There were significantly positive correlations between H2O2 and, MDA levels, catalase activity, and total antioxidant capacity. Cytochrome c oxidase activity and UCP1 mRNA expression significantly decreased in food restricted hamsters compared to the control. These results suggest that warmer temperatures increase oxidative stress in BAT by causing the down-regulation of UCP1 expression and decreased antioxidant activity, but food restriction may attenuate the effects. PMID:27157336

  9. Effect of temperature on biogeochemistry of marine organic-enriched systems: implications in a global warming scenario.

    PubMed

    Sanz-Lázaro, Carlos; Valdemarsen, Thomas; Marín, Arnaldo; Holmer, Marianne

    2011-10-01

    Coastal biogeochemical cycles are expected to be affected by global warming. By means of a mesocosm experiment, the effect of increased water temperature on the biogeochemical cycles of coastal sediments affected by organic-matter enrichment was tested, focusing on the carbon, sulfur, and iron cycles. Nereis diversicolor was used as a model species to simulate macrofaunal bioirrigation activity in natural sediments. Although bioirrigation rates of N. diversicolor were not temperature dependent, temperature did have a major effect on the sediment metabolism. Under organic-enrichment conditions, the increase in sediment metabolism was greater than expected and occurred through the enhancement of anaerobic metabolic pathway rates, mainly sulfate reduction. There was a twofold increase in sediment metabolism and the accumulation of reduced sulfur. The increase in the benthic metabolism was maintained by the supply of electron acceptors through bioirrigation and as a result of the availability of iron in the sediment. As long as the sediment buffering capacity toward sulfides is not surpassed, an increase in temperature might promote the recovery of organic-enriched sediments by decreasing the time for mineralization of excess organic matter. PMID:22073651

  10. Effects of predicted future and current atmospheric temperature and [CO2] and high and low soil moisture on gas exchange and growth of Pinus taeda seedlings at cool and warm sites in the species range.

    PubMed

    Wertin, Timothy M; McGuire, Mary Anne; Teskey, Robert O

    2012-07-01

    Predicted future changes in air temperature and atmospheric CO(2) concentration ([CO(2)]), coupled with altered precipitation, are expected to substantially affect tree growth. Effects on growth may vary considerably across a species range, as temperatures vary from sub-optimal to supra-optimal for growth. We performed an experiment simultaneously at two locations in the current range of loblolly pine, a cool site and a warm site, to examine the effect of future climate conditions on growth of loblolly pine seedlings in contrasting regions of the species range. At both sites 1-year-old loblolly pine seedlings were grown in current (local ambient temperature and [CO(2)]) and predicted future atmospheric conditions (ambient +2 °C temperature and 700 μmol mol(-1) [CO(2)]). Additionally, high and low soil moisture treatments were applied within each atmospheric treatment at each site by altering the amount of water provided to the seedlings. Averaged across water treatments, photosynthesis (A(net)) was 31% greater at the cool site and 34% greater at the warm site in elevated temperature and [CO(2)] compared with ambient temperature. Biomass accumulation was also stimulated by 38% at the cool site and by 24% at the warm site in that treatment. These results suggest that a temperature increase of 2 °C coupled with an increase in [CO(2)] (predicted future climate) will create conditions favorable for growth of this species. Reduced soil moisture decreased growth in both current and predicted atmospheric conditions. Biomass accumulation and A(net) were reduced by ∼39 and 17%, respectively, in the low water treatment. These results suggest that any benefit of future atmospheric conditions may be negated if soil moisture is reduced by altered precipitation patterns. PMID:22696270

  11. Effect of production microclimate on female thermal state with increased temperature and air humidity

    NASA Technical Reports Server (NTRS)

    Machablishvili, O. G.

    1980-01-01

    The thermal state of women during the effect of high air temperature and relative humidity with a varying degree of physical loads was studied. Parameters for air temperature, relative humidity, and air movement were established. It was established that in women the thermo-regulatory stress occurs at lower air temperatures and with lower physical loads than in men. The accumulation of heat in women was revealed with lower air temperature than in men. It is concluded that to preserve the normal physiological state of the female organism it is necessary to create more favorable microclimate conditions and decrease the physical loads.

  12. Effects of social interaction and warm ambient temperature on brain hyperthermia induced by the designer drugs methylone and MDPV.

    PubMed

    Kiyatkin, Eugene A; Kim, Albert H; Wakabayashi, Ken T; Baumann, Michael H; Shaham, Yavin

    2015-01-01

    3,4-Methylenedioxymethcathinone (methylone) and 3,4-methylenedioxypyrovalerone (MDPV) are new drugs of abuse that have gained worldwide popularity. These drugs are structurally similar to 3,4-methylenedioxymethamphetamine (MDMA) and share many of its physiological and behavioral effects in humans, including the development of hyperthermia during acute intoxication. Here, we examined the effects of methylone (1-9 mg/kg, s.c.) or MDPV (0.1-1.0 mg/kg, s.c.) on brain temperature homeostasis in rats maintained in a standard laboratory environment (single-housed in a quiet rest at 22 °C) and under conditions that model human drug use (social interaction and 29 °C ambient temperature). By simultaneously monitoring temperatures in the nucleus accumbens, temporal muscle, and facial skin, we assessed the effects of methylone and MDPV on intra-brain heat production and cutaneous vascular tone, two critical factors that control brain temperature responses. Both methylone and MDPV dose-dependently increased brain temperature, but even at high doses that induced robust locomotor activation, hyperthermia was modest in magnitude (up to ∼2 °C). Both drugs also induced dose-dependent peripheral vasoconstriction, which appears to be a primary mechanism determining the brain hyperthermic responses. In contrast to the powerful potentiation of MDMA-induced hyperthermia by social interaction and warm ambient temperature, such potentiation was absent for methylone and minimal for MDPV. Taken together, despite structural similarities to MDMA, exposure to methylone or MDPV under conditions commonly associated with human drug use does not lead to profound elevations in brain temperature and sustained vasoconstriction, two critical factors associated with MDMA toxicity. PMID:25074640

  13. Effects of Social Interaction and Warm Ambient Temperature on Brain Hyperthermia Induced by the Designer Drugs Methylone and MDPV

    PubMed Central

    Kiyatkin, Eugene A; Kim, Albert H; Wakabayashi, Ken T; Baumann, Michael H; Shaham, Yavin

    2015-01-01

    3,4-Methylenedioxymethcathinone (methylone) and 3,4-methylenedioxypyrovalerone (MDPV) are new drugs of abuse that have gained worldwide popularity. These drugs are structurally similar to 3,4-methylenedioxymethamphetamine (MDMA) and share many of its physiological and behavioral effects in humans, including the development of hyperthermia during acute intoxication. Here, we examined the effects of methylone (1–9 mg/kg, s.c.) or MDPV (0.1–1.0 mg/kg, s.c.) on brain temperature homeostasis in rats maintained in a standard laboratory environment (single-housed in a quiet rest at 22 °C) and under conditions that model human drug use (social interaction and 29 °C ambient temperature). By simultaneously monitoring temperatures in the nucleus accumbens, temporal muscle, and facial skin, we assessed the effects of methylone and MDPV on intra-brain heat production and cutaneous vascular tone, two critical factors that control brain temperature responses. Both methylone and MDPV dose-dependently increased brain temperature, but even at high doses that induced robust locomotor activation, hyperthermia was modest in magnitude (up to ∼2 °C). Both drugs also induced dose-dependent peripheral vasoconstriction, which appears to be a primary mechanism determining the brain hyperthermic responses. In contrast to the powerful potentiation of MDMA-induced hyperthermia by social interaction and warm ambient temperature, such potentiation was absent for methylone and minimal for MDPV. Taken together, despite structural similarities to MDMA, exposure to methylone or MDPV under conditions commonly associated with human drug use does not lead to profound elevations in brain temperature and sustained vasoconstriction, two critical factors associated with MDMA toxicity. PMID:25074640

  14. Intensification of seasonal temperature extremes prior to the 2°C global warming target

    NASA Astrophysics Data System (ADS)

    Anderson, B. T.

    2011-12-01

    Given current international efforts to limit human-induced global-mean near-surface temperature increases to 2°C, relative to the pre-industrial era, there is an interest in determining what unavoidable impacts to physical, biological, and socio-economic systems might occur even if this target were met. In our research we show that substantial fractions of the globe could experience seasonal-mean temperature extremes with unprecedented regularity, even if the global-mean temperature remains below the 2°C target currently envisioned. These results have significant implications for agriculture and crop yield; disease and human health; and ecosystems and biodiversity. To obtain these results, we first develop a novel method for combining numerical-model estimates of near-term increases in grid-point temperatures with stochastically generated anomalies derived from high-resolution observations during the last half of the 20th century. This method has practical advantages because it generates results at fine spatial resolution without relying on computationally-intensive regional-model experiments; it explicitly incorporates information derived from the observations regarding interannual-to-decadal variations in seasonal-mean temperatures; and it includes the generation of thousands of realizations of the possible impacts of a global mean temperature increase on local occurrences of hot extremes. Using this method we find that even given the "committed" future global-mean temperature increase of 0.6°C (1.4°C relative to the pre-industrial era) historical seasonal-mean temperature extremes will be exceeded in at least half of all years-equivalently, the historical extreme values will become the norm-for much of Africa, the southeastern and central portions of Asia, Indonesia, and the Amazon. Should the global-mean temperature increase reach 2°C (relative to the pre-industrial era), it is more likely than not that these same regions, along with large portions of

  15. Estimating Air Temperature over the Tibetan Plateau Using MODIS Data

    NASA Astrophysics Data System (ADS)

    Huang, Fangfang; Ma, Weiqiang; Ma, Yaoming; Li, Maoshan; Hu, Zeyong

    2016-04-01

    Time series of MODIS land surface temperature (LST) data and normalized difference vegetation index (NDVI) data, combined with digital elevation model (DEM) and meterological data for 2001-2012, were used to estimate and map the spatial distribution of monthly mean air temperature over the Tibatan Plateau (TP). Time series and regression analysis of monthly mean land surface temperature (Ts) and air temperature (Ta) were both conducted by ordinary liner regression (OLR) and geographical weighted regression (GWR) methods. Analysis showed that GWR method had much better result (Adjusted R2 > 0.79, root mean square error (RMSE) is between 0.51° C and 1.12° C) for estimating Ta than OLR method. The GWR model, with MODIS LST, NDVI and altitude as independent variables, was used to estimate Ta over the Tibetan Plateau. All GWR models in each month were tested by F-test with significant level of α=0.01 and the regression coefficients were all tested by T-test with significant level of α=0.01. This illustrated that Ts, NDVI and altitude play an important role on estimating Ta over the Tibetan Plateau. Finally, the major conclusions are as follows: (1) GWR method has higher accuracy for estimating Ta than OLR (Adjusted R2=0.40˜0.78, RMSE=1.60˜4.38° C), and the Ta control precision can be up to 1.12° C. (2) Over the Northern TP, the range of Ta variation in January is -29.28 ˜ -5.0° C, and that in July is -0.53 ˜ 14.0° C. Ta in summer half year (from May to October) is between -15.92 ˜ 14.0° C. From October on, 0° C isothermal level is gradually declining from the altitude of 4˜5 kilometers, and hits the bottom with altitude of 3200 meters in December, and Ta is all under 0° C in January. 10° C isothermal level gradually starts rising from the altitude of 3200 meters from May, and reaches the highest level with altitude of 4˜5 kilometers in July. In addition, Ta in south slope of the Tanggula Mountains is obviously higher than that in the north slope. Ta

  16. Statistical Variability and Persistence Change in Daily Air Temperature Time Series from High Latitude Arctic Stations

    NASA Astrophysics Data System (ADS)

    Suteanu, Cristian

    2015-07-01

    In the last decades, Arctic communities have been reporting that weather conditions are becoming less predictable. Most scientific studies have not been able to consistently confirm such a trend. The question regarding the possible increase in weather variability was addressed here based on daily minimum and maximum surface air temperature time series from 15 high latitude Arctic stations from Canada, Norway, and the Russian Federation. A range of analysis methods were applied, distinguished mainly by the way in which they treat time scale. Statistical L-moments were determined for temporal windows of different lengths. While the picture provided by L-scale and L-kurtosis is not consistent with an increasing variability, L-skewness was found to change towards more positive values, reflecting an enhancement of warm spells. Haar wavelet analysis was applied both to the entire time series and to running windows. Persistence diagrams were generated based on running windows advancing through time and on local slopes of Haar analysis graphs; they offer a more nuanced view on variability by reflecting its change over time on a range of temporal scales. Local increases in variability could be identified in some cases, but no consistent change was detected in any of the stations over the studied temporal scales. The possibility for other intervals of temporal scale (e.g., days, hours, minutes) to potentially reveal a different situation cannot be ruled out. However, in the light of the results presented here, explanations for the discrepancy between variability perception and results of pattern analysis might have to be explored using an integrative approach to weather variables such as air temperature, cloud cover, precipitation, wind, etc.

  17. Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells

    PubMed Central

    Foxman, Ellen F.; Storer, James A.; Fitzgerald, Megan E.; Wasik, Bethany R.; Hou, Lin; Zhao, Hongyu; Turner, Paul E.; Pyle, Anna Marie; Iwasaki, Akiko

    2015-01-01

    Most isolates of human rhinovirus, the common cold virus, replicate more robustly at the cool temperatures found in the nasal cavity (33–35 °C) than at core body temperature (37 °C). To gain insight into the mechanism of temperature-dependent growth, we compared the transcriptional response of primary mouse airway epithelial cells infected with rhinovirus at 33 °C vs. 37 °C. Mouse airway cells infected with mouse-adapted rhinovirus 1B exhibited a striking enrichment in expression of antiviral defense response genes at 37 °C relative to 33 °C, which correlated with significantly higher expression levels of type I and type III IFN genes and IFN-stimulated genes (ISGs) at 37 °C. Temperature-dependent IFN induction in response to rhinovirus was dependent on the MAVS protein, a key signaling adaptor of the RIG-I–like receptors (RLRs). Stimulation of primary airway cells with the synthetic RLR ligand poly I:C led to greater IFN induction at 37 °C relative to 33 °C at early time points poststimulation and to a sustained increase in the induction of ISGs at 37 °C relative to 33 °C. Recombinant type I IFN also stimulated more robust induction of ISGs at 37 °C than at 33 °C. Genetic deficiency of MAVS or the type I IFN receptor in infected airway cells permitted higher levels of viral replication, particularly at 37 °C, and partially rescued the temperature-dependent growth phenotype. These findings demonstrate that in mouse airway cells, rhinovirus replicates preferentially at nasal cavity temperature due, in part, to a less efficient antiviral defense response of infected cells at cool temperature. PMID:25561542

  18. Inter-comparison of upper air temperature over China between Radiosonde and Reanalysis Data

    NASA Astrophysics Data System (ADS)

    Guo, Yanjun; Zhang, Siqi; Yan, Jinghui; Chen, Zhe; Ruan, Xin

    2016-04-01

    Based on quality controlled(RAW) and homogenized(ADJ) radiosonde temperatures at 850-30hPa from 118 stations in China and monthly mean temperatures from eight reanalysis datasets(REA) which included NCEPv1, NCEPv2, ERA-40, ERA-Interim, JRA55, 20CR, MERRA and CFSR, a preliminary comparison of upper air temperatures over China between radiosonde and reanalysis was undertaken. The mean difference, correlation, standard deviation and linear trend between RAW and ADJ, REA and RAW, REA and ADJ during 1981-2010 were analyzed and results demonstrated ADJ temperatures averaged in China were generally cooler than RAW and the negative adjustments were the most significant at the upper troposphere and the lower stratosphere. Homogenization removed the system error caused by radiosonde instrument and observation system update from RAW. Hence the correlations between REA and ADJ were higher than those between REA and RAW. ADJ is more suitable than RAW as an evaluation index of reanalysis data. The mean difference between REA and ADJ were about 1C during 1981-2010, while REA were generally cooler than ADJ in the troposphere and warmer in the stratosphere. Significant correlations proved the consistence of annual variability between REA and ADJ. The linear trends are consistent between REA and ADJ with warming in the lower and middle troposphere and cooling in the middle stratosphere. More uncertainly were revealed at the upper troposphere and the lower stratosphere. ERA-Interim, JRA55 and MERRA were generally closer to ADJ than other reanalysis datasets.

  19. How will fish that evolved at constant sub-zero temperatures cope with global warming? Notothenioids as a case study.

    PubMed

    Patarnello, Tomaso; Verde, Cinzia; di Prisco, Guido; Bargelloni, Luca; Zane, Lorenzo

    2011-04-01

    Current climate change has raised concerns over the fate of the stenothermal Antarctic marine fauna (animals that evolved to live in narrow ranges of cold temperatures). The present paper focuses on Notothenioidei, a taxonomic group that dominates Antarctic fish. Notothenioids evolved in the Southern Ocean over the last 20 million years, providing an example of a marine species flock with unique adaptations to the cold at morphological, physiological and biochemical levels. Their phenotypic modifications are often accompanied by 'irreversible' genomic losses or gene amplifications. On a micro-evolutionary scale, relatively 'shallow' genetic variation is observed, on account of past fluctuations in population size, and a significant genetic structure is evident, suggesting low population connectivity. These features suggest that Antarctic fish might have relatively little potential to adapt to global warming, at least at a genetic level. The extent of their phenotypic plasticity, which is evident to some degree, awaits further research. PMID:21290397

  20. Topographic and spatial impacts of temperature inversions on air quality using mobile air pollution surveys.

    PubMed

    Wallace, Julie; Corr, Denis; Kanaroglou, Pavlos

    2010-10-01

    We investigated the spatial and topographic effects of temperature inversions on air quality in the industrial city of Hamilton, located at the western tip of Lake Ontario, Canada. The city is divided by a 90-m high topographic scarp, the Niagara Escarpment, and dissected by valleys which open towards Lake Ontario. Temperature inversions occur frequently in the cooler seasons, exacerbating the impact of emissions from industry and traffic. This study used pollution data gathered from mobile monitoring surveys conducted over a 3-year period, to investigate whether the effects of the inversions varied across the city. Temperature inversions were identified with vertical temperature data from a meteorological tower located within the study area. We divided the study area into an upper and lower zone separated by the Escarpment and further into six zones, based on location with respect to the Escarpment and industrial and residential areas, to explore variations across the city. The results identified clear differences in the responses of nitrogen dioxide (NO(2)) and fine particulate matter (PM2.5) to temperature inversions, based on the topographic and spatial criteria. We found that pollution levels increased as the inversion strengthened, in the lower city. However, the results also suggested that temperature inversions identified in the lower city were not necessarily experienced in the upper city with the same intensity. Further, pollution levels in the upper city appeared to decrease as the inversion deepened in the lower city, probably because of an associated change in prevailing wind direction and lower wind speeds, leading to decreased long-range transport of pollutants. PMID:20705328

  1. Temperature and density dependence of XANES spectra in warm dense aluminum plasmas

    SciTech Connect

    Recoules, V.; Mazevet, S.

    2009-08-01

    Using ab initio molecular-dynamics simulations combined with linear-response theory, we calculate the density and temperature dependence of the x-ray absorption near-edge structure (XANES) of a dense aluminum plasma. At solid density and for temperatures increasing up to 6 eV, we see that the XANES spectrum loses its well-known room-temperature structure, first due to melting and second due to loss of correlation in the liquid. Similarly, as the density decreases and the system evolves from a liquid to a plasma, the XANES spectrum becomes less structured. As the density is further lowered and the system turns into an atomic fluid, a pre-edge forms as the 3p state becomes bound. We suggest that direct measurements of the XANES spectra in this density region is a unique opportunity to validate pressure ionization models routinely used in plasma physics modeling.

  2. Rayleigh/raman Greenland Lidar Observations of Atmospheric Temperature During a Major Arctic Stratospheric Warming Event

    NASA Technical Reports Server (NTRS)

    Meriwether, John W.; Farley, Robert; Mcnutt, R.; Dao, Phan D.; Moskowitz, Warren P.

    1992-01-01

    Between Jan. 22 1991 to Feb. 5 1991, we made numerous observations of atmospheric temperature profiles between 10 and 70 km by using the combination of Rayleigh and Raman lidar systems contained in the PL Mobile Lidar Facility located at the National Science Foundation Incoherent Radar Facility of Sondrestrom in Greenland. The purpose of these measurements was to observe the dynamics of the winter Arctic stratosphere and mesosphere regions during a winter period from the succession of temperature profiles obtained in our campaign observations. Various aspects of this investigation are presented.

  3. Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions.

    PubMed

    Moyes, Andrew B; Germino, Matthew J; Kueppers, Lara M

    2015-09-01

    Climate change is altering plant species distributions globally, and warming is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with warming difficult to predict. We measured response functions linking carbon (C) assimilation and temperature- and moisture-related microclimatic factors for limber pine (Pinus flexilis) seedlings growing in a heating × watering experiment within and above the alpine treeline. We then extrapolated these response functions using observed microclimate conditions to estimate the net effects of warming and associated soil drying on C assimilation across an entire growing season. Moisture and temperature limitations were each estimated to reduce potential growing season C gain from a theoretical upper limit by 15-30% (c. 50% combined). Warming above current treeline conditions provided relatively little benefit to modeled net assimilation, whereas assimilation was sensitive to either wetter or drier conditions. Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as seasonally dry subalpine and alpine ecosystems continue to warm. PMID:25902893

  4. Maintaining Warm, Trusting Relationships with Brands: Increased Temperature Perceptions after Thinking of Communal Brands