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Sample records for air temperature leaf

  1. Estimating Pan Arctic Net Ecosystem Exchange using Functional Relationships with Air temperature, Leaf Area Index and Photosynthetic Active Radiation

    NASA Astrophysics Data System (ADS)

    Mbufong, H.; Kusbach, A.; Lund, M.; Persson, A.; Christensen, T. R.; Tamstorf, M. P.; Connolly, J.

    2015-12-01

    The high variability in Arctic tundra net ecosystem exchange (NEE) of carbon (C) is often attributed to the high spatial heterogeneity of Arctic tundra. Current models of carbon exchange thus handle the Arctic as either a single or few ecosystems, responding to environmental change in the same manner. In this study, we developed and tested a simple NEE model using the Misterlich light response curve (LRC) function with photosynthetic photon flux density (PPFD) as the main driving variable. Model calibration was carried out with eddy covariance carbon dioxide data from 12 Arctic tundra sites. The model input parameters (fcsat, Rd and α) were estimated as a function of air temperature and leaf area index (LAI) and represent specific characteristics of the NEE-PPFD relationship. They describe the saturation flux, dark respiration and initial light use efficiency, respectively. While remotely sensed LAI is readily available as a MODIS Terra product (MCD15A3), air temperature was estimated from a direct relationship with MODIS land surface temperature (MOD11A2, LST). Therefore, no specific knowledge of the vegetation type is required. Preliminary results show the model captures the spatial heterogeneity of the Arctic tundra but so far, overestimates NEE on all 17 test sites which include heaths, bogs, fens, and tussock tundra vegetation. The final updated results and error assessment will be presented at the conference in December.

  2. Monitoring Air Quality with Leaf Yeasts.

    ERIC Educational Resources Information Center

    Richardson, D. H. S.; And Others

    1985-01-01

    Proposes that leaf yeast serve as quick, inexpensive, and effective techniques for monitoring air quality. Outlines procedures and provides suggestions for data analysis. Includes results from sample school groups who employed this technique. (ML)

  3. Spring Wheat Leaf Appearance and Temperature: Extending the Paradigm?

    PubMed Central

    MCMASTER, GREGORY S.; WILHELM, W. W.; PALIC, D. B.; PORTER, JOHN R.; JAMIESON, P. D.

    2003-01-01

    Extensive research shows temperature to be the primary environmental factor controlling the phyllochron, or rate of leaf appearance, of wheat (Triticum aestivum L.). Experimental results suggest that soil temperature at crown depth, rather than air temperature above the canopy, would better predict wheat leaf appearance rates. To test this hypothesis, leaf appearance in spring wheat (‘Nordic’) was measured in a 2‐year field experiment (Nunn clay loam soil; fine, smectitic, mesic Aridic, Argiustoll) with three planting dates and two soil temperature treatments. One temperature treatment (denoted +3C) consisted of heating the soil at crown depth to 3 °C above the ambient soil temperature (denoted +0C). Main stem cumulative leaf number was measured at least weekly until flag leaf emergence. Leaf appearance was essentially linear with both air and soil growing degree‐days (GDD), although there was a stronger linear relationship with soil GDD in the +0C plants than in +3C plants. A weak positive relationship between planting date and the phyllochron was observed. Unexpectedly, we found that heating the soil did not increase the rate of leaf appearance, as the paradigm would predict. To explain these results, we propose extending the paradigm in two ways. First, three processes are involved in leaf appearance: (1) cell division at the shoot apex forms the primordium; (2) cell division in the intercalary meristem forms the cells that then (3) expand to produce the leaf. Cell division is predominately controlled by temperature, but cell expansion is considerably more affected by factors other than temperature, explaining the influence of other factors on the phyllochron. Secondly, the vertical distribution of the two meristems and region of cell expansion occur over a significant distance, where temperature varies considerably, and temperature at a specific point (e.g. crown depth) does not account for the entire temperature regime under which leaves are

  4. Air bubble bursting effect of lotus leaf.

    PubMed

    Wang, Jingming; Zheng, Yongmei; Nie, Fu-Qiang; Zhai, Jin; Jiang, Lei

    2009-12-15

    In this paper, a phenomenon of air bubbles quickly bursting within several milliseconds on a "self-cleaning" lotus leaf was described. This observation prompted the synthesis of artificial surfaces similar to that of the lotus leaf. The artificial leaf surfaces, prepared by photolithography and wet etching, showed a similar air bubble bursting effect. Smooth and rough silicon surfaces with an ordered nanostructure or patterned microstructure were utilized to study the contribution of the micro/nano hierarchical structures to this phenomenon of air bubble bursting. Air bubbles were found to burst on some superhydrophobic surfaces with microstructure (within 220 ms). However, air bubbles burst much more rapidly (within 13 ms) on similar surfaces with micro/nanostructure. The height, width, and spacing of hierarchical structures could also affect air bubble bursting, and the effect of the height was more obvious. When the height of hierarchical structures was around the height found in natural lotus papillae, the width and spacing were significant for air bubble bursting. An original model was proposed to further evaluate the reason why the micro/nano hierarchical rough structures had an excellent air bubble bursting effect, and the validity of the model was theoretically demonstrated.

  5. Comparing model predictions and experimental data for the response of stomatal conductance and guard cell turgor to manipulations of cuticular conductance, leaf-to-air vapour pressure difference and temperature: feedback mechanisms are able to account for all observations.

    PubMed

    Eamus, Derek; Taylor, Daniel T; Macinnis-Ng, Catriona M O; Shanahan, Steve; De Silva, Lionel

    2008-03-01

    Stomata respond to increasing leaf-to-air vapour pressure difference (LAVPD) (D) by closing. The mechanism by which this occurs is debated. A role for feedback and peristomatal transpiration has been proposed. In this paper, we apply a recent mechanistic model of stomatal behaviour, and compare model and experimental data for the influence of increasing D on stomatal conductance. We manipulated cuticular conductance (g(c)) by three independent methods. First, we increased g(c) by using a solvent mixture applied to both leaf surfaces prior to determining stomatal responses to D; second, we increased g(c) by increasing leaf temperature at constant D; and third, we coated a small area of leaf with a light oil to decrease g(c). In all three experiments, experimental data and model outputs showed very close agreement. We conclude, from the close agreement between model and experimental data and the fact that manipulations of g(c), and hence cuticular transpiration, influenced g(s) in ways consistent with a feedback mechanism, that feedback is central in determining stomatal responses to D.

  6. Vertical and seasonal variations in temperature responses of leaf respiration in a Chamaecyparis obtusa canopy.

    PubMed

    Araki, Masatake G; Gyokusen, Koichiro; Kajimoto, Takuya

    2017-02-23

    Leaf respiration (R) is a major component of carbon balance in forest ecosystems. Clarifying the variability of leaf R within a canopy is essential for predicting the impact of global warming on forest productivity and the potential future function of the forest ecosystem as a carbon sink. We examined vertical and seasonal variations in short-term temperature responses of leaf R as well as environmental factors (light and mean air temperature) and physiological factors [leaf nitrogen (N), leaf mass per area (LMA), and shoot growth] in the canopy of a 10-year-old stand of hinoki cypress [Chamaecyparis obtusa (Sieb. et Zucc.) Endl.] in Kyushu, Japan. Leaf respiration rate adjusted to 20 °C (R20) exhibited evident vertical gradients in each season and was correlated with light, LMA and leaf N. In contrast, the temperature sensitivity of leaf R (Q10) did not vary vertically throughout the seasons. Seasonally, Q10 was higher in winter than in summer and was strongly negatively correlated to mean air temperature. A negative correlation of R20 with mean air temperature was also observed for each of the three canopy layers. These results clearly indicate that leaf R was able to adjust to seasonal changes in ambient temperature under field conditions and down-regulate during warmer periods. We also found that the degree of thermal acclimation did not vary with canopy position. Overall, our results suggest that vertical and seasonal variations in temperature responses of leaf R within a hinoki cypress canopy could be predicted by relatively simple parameters (light and temperature). There was an exception of extremely high R20 values in April that may have been due to the onset of shoot growth in spring. Understanding thermal acclimation and variations in leaf R within forest canopies will improve global terrestrial carbon cycle models.

  7. Temperature and Transpiration Resistances of Xanthium Leaves as Affected by Air Temperature, Humidity, and Wind Speed 1

    PubMed Central

    Drake, B. G.; Raschke, K.; Salisbury, F. B.

    1970-01-01

    Transpiration and temperatures of single, attached leaves of Xanthium strumarium L. were measured in high intensity white light (1.2 calories per square centimeter per minute on a surface normal to the radiation), with abundant water supply, at wind speeds of 90, 225, and 450 centimeters per second, and during exposure to moist and dry air. Partitioning of absorbed radiation between transpiration and convection was determined, and transpiration resistances were computed. Leaf resistances decreased with increasing temperature (down to a minimum of 0.36 seconds per centimeter). Silicone rubber replicas of leaf surfaces proved that the decrease was due to increased stomatal apertures. At constant air temperature, leaf resistances were higher in dry than in moist air with the result that transpiration varied less than would have been predicted on the basis of the water-vapor pressure difference between leaf and air. The dependence of stomatal conductance on temperature and moisture content of the air caused the following effects. At air temperatures below 35 C, average leaf temperatures were above air temperature by an amount dependent on wind velocity; increasing wind diminished transpiration. At air temperatures above 35 C, leaf temperatures were below air temperatures, and increasing wind markedly increased transpiration. Leaf temperatures equaled air temperature near 35 C at all wind speeds and in moist as well as in dry air. PMID:16657458

  8. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes

    PubMed Central

    Nelson, Jacob A.; Bugbee, Bruce

    2015-01-01

    The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies. PMID:26448613

  9. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes.

    PubMed

    Nelson, Jacob A; Bugbee, Bruce

    2015-01-01

    The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

  10. Temperature, light and leaf hydraulic conductance of little-leaf linden (Tilia cordata) in a mixed forest canopy.

    PubMed

    Sellin, Arne; Kupper, Priit

    2007-05-01

    Response of whole-leaf hydraulic conductance (G(L)) in little-leaf linden (Tilia cordata Mill.) to temperature and photosynthetic photon flux (Q(P)) was estimated by the evaporative flux method under natural conditions in a mixed forest canopy. Mean midday G(L) in the lower- and upper-crown foliage was 1.14 and 3.06 mmol m(-2) s(-1) MPa(-1), respectively. Over the study period, leaf temperature (T(L)) explained about 67% of the variation in G(L), and Q(P) explained about 10%. Leaf water potential and crown position also affected G(L) significantly. About a third of the temperature effect was attributable to changes in the viscosity of water, and two thirds to changes in protoplast permeability (i.e., symplastic conductance). Leaf hydraulic conductance was highly sensitive to changes in Q(P) when Q(P) was less than 200 micromol m(-2) s(-1), and G(L) sensitivity decreased with increasing irradiance. Sensitivity of G(L) to variation in T(L) increased consistently with increasing temperature in the range of 16 to 29 degrees C. There were positive interactions between temperature and light in their effects on G(L): the light response was more pronounced at higher leaf temperatures. Because of frequent rains during the study period, the trees experienced no soil water deficit, and, within the range experienced, soil water potential had no effect on G(L). Leaf hydraulic conductance exhibited a seasonal pattern that could be explained primarily by temporal variability in mean air temperature and irradiance, in addition to which an age-related trend (P<0.001) of increasing G(L) from the end of June to the beginning of August was observed.

  11. Effects of elevated atmospheric CO(2) and temperature on leaf optical properties in Acer saccharum.

    PubMed

    Carter; Bahadur; Norby

    2000-06-01

    Elevated partial pressures of atmospheric carbon dioxide, similar to numerous causes of plant stress, may alter leaf pigmentation and structure and thus would be expected to alter leaf optical properties. Hypotheses that elevated CO(2) pressure and air temperature would alter leaf optical properties were tested for sugar maple (Acer saccharum) in the middle of its fourth growing season under treatment. The saplings had been growing since 1994 in open-top chambers and partial shade at Oak Ridge, Tennessee under the following treatments: (1) ambient CO(2) pressure and air temperature (control); (2) CO(2) pressure approximately 30 Pa above ambient; (3) air temperatures 3 degrees C above ambient; and (4) elevated CO(2) and air temperature. Under elevated CO(2) or temperature, spectral reflectance, transmittance and absorptance in the visible spectrum (400-720 nm) tended to change in patterns that generally are associated with chlorosis, with maximum differences from the control near 700 nm. However, these changes were not significant at P=0.05. Although reflectance, transmittance and absorptance at 700 nm correlated strongly with leaf chlorophyll concentration, variability in chlorophyll concentration was greater within than among treatments. The lack of treatment effects on pigmentation explained the non-significant change in optical properties in the visible spectrum. Optical properties in the near-infrared (721-850 nm) were similarly unresponsive to treatment with the exception of an increased absorptance throughout the 739-850 nm range in leaves that developed under elevated air temperature alone. This response might have resulted from effects of air temperature on leaf internal structure.

  12. Plant water stress, leaf temperature, and spider mite (Acari: Tetranychidae) outbreaks in California vineyards.

    PubMed

    Stavrinides, Menelaos C; Daane, Kent M; Lampinen, Bruce D; Mills, Nicholas J

    2010-08-01

    We evaluated the relationships between plant water status and leaf temperature, and between leaf temperature and spider mite (Acari: Tetranychidae) and predatory mite (Acari: Phytoseiidae) populations in eight vineyards in California in 2006 and 2007. Temperature of south-facing leaves increased significantly by 0.8°C for every 1.0°C increase in ambient air temperature, and by 5.3°C for every one MPa drop in leaf water potential. Peak population densities of Pacific spider mite, Tetranychus pacificus McGregor, increased significantly with increasing frequency of leaf temperatures above 31°C. In contrast, peak population densities of Willamette spider mite, Eotetranychus willamettei (McGregor), showed no relationship with the frequency of leaf temperatures above 31°C. This differential relationship between the two mite species and high leaf temperatures is consistent with their upper thresholds for development, which are 40°C for T. pacificus and 31°C for E. willamettei, as identified in a previous study. Predatory mite population densities showed no relationship with peak population densities of either spider mite species during the analysis period, but decreased with the frequency of leaf temperatures above 31°C. In addition, predatory mite population densities were significantly higher on south-facing than interior leaves after adjusting for the effect of leaf temperature. These results help to explain why outbreaks of T. pacificus occur in warmer or water-stressed vineyards, whereas E. willamettei develops higher populations in cooler or well-irrigated vineyards. In addition, these results suggest that regulated deficit irrigation should be implemented with caution, especially in those vineyards with a high risk of T. pacificus outbreaks.

  13. Global Patterns in Leaf Respiration and its Temperature Response

    NASA Astrophysics Data System (ADS)

    Heskel, M.; Atkin, O. K.; O'Sullivan, O. S.; Reich, P. B.; Tjoelker, M. G.; Weerasinghe, L. K.; Penillard, A.; Egerton, J. J. G.; Creek, D.; Bloomfield, K. J.; Xiang, J.; Sinca, F.; Stangl, Z.; Martinez-de la Torre, A.; Griffin, K. L.; Huntingford, C.; Hurry, V.; Meir, P.; Turnbull, M.

    2015-12-01

    Leaf respiration (R) represents a massive flux of carbon to the atmosphere. Currently, neither physiological models nor terrestrial biosphere models are able to disentangle sources of variation in leaf R among different plant species and contrasting environments. Similarly, such models do not adequately describe the short-term temperature (T) response of R, which can lead to inaccurate representation of leaf R in simulation models of regional and global terrestrial carbon cyling. Even minor differences in the underlying basal rate of leaf R and/or shape of the T-response curve can significantly impact estimates of carbon released and stored in ecosystems. Given this, we recently assembled and analyzed two new global databases (arctic-to-tropics) of leaf R and its short-term T-dependence. The results highlight variation in basal leaf R among species and across global gradients in T and aridity, with leaf R at a standard T (e.g. 25°C) being greatest in plants growing in the cold, dry Arctic and lowest in the warm, moist tropics. Arctic plants also exhibit higher rates of leaf R at a given photosynthetic capacity or leaf N concentration than their tropical counterparts. The results also point to convergence in the short-term temperature response of respiration across biomes and plant functional types. The applicability and significance of the short-term T-response of R for simulation models of plant and ecosystem carbon fluxes will be discussed.

  14. REGULATION OF ISOPRENE EMISSION RESPONSES TO RAPID LEAF TEMPERATURE FLUCTUATIONS

    EPA Science Inventory

    Isoprene emission from leaves is temperature dependent and may protect them from damage at high temperatures. We measured the temperature of white oak (Quercus alba L.) leaves at the top of the canopy. The largest changes in leaf temperature were associated with changes in solar ...

  15. Higher daytime leaf temperatures contribute to lower freeze tolerance under elevated CO2.

    PubMed

    Loveys, Beth R; Egerton, John J G; Ball, Marilyn C

    2006-06-01

    Elevated atmospheric CO2 adversely affects freezing tolerance in many evergreens, but the underlying mechanism(s) have been elusive. We compared effects of elevated CO2 with those of daytime warming on acclimation of snow gum (Eucalyptus pauciflora) to freezing temperatures under field conditions. Reduction in stomatal conductance g(c) under elevated CO2 was shown to cause leaf temperature to increase by up to 3 degrees C. In this study, this increase in leaf temperature was simulated under ambient CO2 conditions by using a free air temperature increase (FATI) system to warm snow gum leaves during daytime, thereby increasing the diurnal range in temperature without affecting temperature minima. Acclimation to freezing temperatures was assessed using measures of electrolyte leakage and photosynthetic efficiency of leaf discs exposed to different nadir temperatures. Here, we show that both elevated CO2 and daytime warming delayed acclimation to freezing temperatures for 2-3 weeks after which time freeze tolerance of the treated plants in both the FATI and open top chamber (OTC) experiments did not differ from control plants. Our results support the hypothesis that delayed development of freezing tolerance under elevated CO2 is because of higher daytime leaf temperatures under elevated CO2. Thus, potential gains in productivity in response to increasing atmospheric CO2 and prolonging the growing season may be reduced by an increase in freezing stress in frost-prone area.

  16. AN EVALUATION OF THREE EMPIRICAL AIR-TO-LEAF ...

    EPA Pesticide Factsheets

    Three empirical air-to-leaf models for estimating grass concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (abbreviated dioxins and furans) from air concentrations of these compounds are described and tested against two field data sets. All are empirical in that they are founded on simplistic bioconcentration and related approaches which rely on field data for their parameterization. One of the models, identified as the EPA Model, partitions the total air concentration into vapor and particle phases, and separately models the impact of both. A second model addresses only the vapor phase; grass concentrations are modeled as a function of vapor deposition. For the third model, it is assumed that the grass plants

  17. Leaf structural characteristics are less important than leaf chemical properties in determining the response of leaf mass per area and photosynthesis of Eucalyptus saligna to industrial-age changes in [CO2] and temperature.

    PubMed

    Xu, Cheng-Yuan; Salih, Anya; Ghannoum, Oula; Tissue, David T

    2012-10-01

    The rise in atmospheric [CO(2)] is associated with increasing air temperature. However, studies on plant responses to interactive effects of [CO(2)] and temperature are limited, particularly for leaf structural attributes. In this study, Eucalyptus saligna plants were grown in sun-lit glasshouses differing in [CO(2)] (290, 400, and 650 µmol mol(-1)) and temperature (26 °C and 30 °C). Leaf anatomy and chloroplast parameters were assessed with three-dimensional confocal microscopy, and the interactive effects of [CO(2)] and temperature were quantified. The relative influence of leaf structural attributes and chemical properties on the variation of leaf mass per area (LMA) and photosynthesis within these climate regimes was also determined. Leaf thickness and mesophyll size increased in higher [CO(2)] but decreased at the warmer temperature; no treatment interaction was observed. In pre-industrial [CO(2)], warming reduced chloroplast diameter without altering chloroplast number per cell, but the opposite pattern (reduced chloroplast number per cell and unchanged chloroplast diameter) was observed in both current and projected [CO(2)]. The variation of LMA was primarily explained by total non-structural carbohydrate (TNC) concentration rather than leaf thickness. Leaf photosynthetic capacity (light- and [CO(2)]-saturated rate at 28 °C) and light-saturated photosynthesis (under growth [CO(2)] and temperature) were primarily determined by leaf nitrogen contents, while secondarily affected by chloroplast gas exchange surface area and chloroplast number per cell, respectively. In conclusion, leaf structural attributes are less important than TNC and nitrogen in affecting LMA and photosynthesis responses to the studied climate regimes, indicating that leaf structural attributes have limited capacity to adjust these functional traits in a changing climate.

  18. Influence of temperature gradients on leaf water potential.

    PubMed

    Wiebe, H H; Prosser, R J

    1977-02-01

    Water potential was monitored at nine locations along single maize (Zea mays L.) leaf blades with aluminum block in situ thermocouple hygrometers. Water potential showed a continuous decrease toward the tip, with a 2- to 4-bar difference between leaf base and tip under both moist and dry soil conditions. The water potential difference between the soil and the leaf base was about 4 bars. Water potentials decreased during the day and during a drying cycle, and increased at night and after irrigation. Heating a band of a leaf to 40 C or cooling it to 7 C had no influence on the water potential of the affected portion when this was corrected for hygrometer output over standard calibrating solutions at the respective temperatures. Heating or cooling a portion of a leaf had neither short nor long term effects on water potential of more distal leaf portions continuously monitored by hygrometers in dew point readout. Water potential fluctuated with an amplitude of about 1.5 bars and an irregular period of 10 to 30 minutes. Measurements with silver foil in situ psychrometers gave similar results.

  19. Characterization of leaf blade- and leaf sheath-associated bacterial communities and assessment of their responses to environmental changes in CO₂, temperature, and nitrogen levels under field conditions.

    PubMed

    Ikeda, Seishi; Tokida, Takeshi; Nakamura, Hirofumi; Sakai, Hidemitsu; Usui, Yasuhiro; Okubo, Takashi; Tago, Kanako; Hayashi, Kentaro; Sekiyama, Yasuyo; Ono, Hiroshi; Tomita, Satoru; Hayatsu, Masahito; Hasegawa, Toshihiro; Minamisawa, Kiwamu

    2015-01-01

    Rice shoot-associated bacterial communities at the panicle initiation stage were characterized and their responses to elevated surface water-soil temperature (ET), low nitrogen (LN), and free-air CO2 enrichment (FACE) were assessed by clone library analyses of the 16S rRNA gene. Principal coordinate analyses combining all sequence data for leaf blade- and leaf sheath-associated bacteria revealed that each bacterial community had a distinct structure, as supported by PC1 (61.5%), that was mainly attributed to the high abundance of Planctomycetes in leaf sheaths. Our results also indicated that the community structures of leaf blade-associated bacteria were more sensitive than those of leaf sheath-associated bacteria to the environmental factors examined. Among these environmental factors, LN strongly affected the community structures of leaf blade-associated bacteria by increasing the relative abundance of Bacilli. The most significant effect of FACE was also observed on leaf blade-associated bacteria under the LN condition, which was explained by decreases and increases in Agrobacterium and Pantoea, respectively. The community structures of leaf blade-associated bacteria under the combination of FACE and ET were more similar to those of the control than to those under ET or FACE. Thus, the combined effects of environmental factors need to be considered in order to realistically assess the effects of environmental changes on microbial community structures.

  20. Effect of Elevated Atmospheric CO2 and Temperature on Leaf Optical Properties and Chlorophyll Content in Acer saccharum (Marsh.)

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Bahadur, Raj; Norby, Richard J.

    1999-01-01

    Elevated atmospheric CO2 pressure and numerous causes of plant stress often result in decreased leaf chlorophyll contents and thus would be expected to alter leaf optical properties. Hypotheses that elevated carbon dioxide pressure and air temperature would alter leaf optical properties were tested for sugar maple (Acer saccharum Marsh.) in the middle of its fourth growing season under treatment. The saplings had been growing since 1994 in open-top chambers at Oak Ridge, Tennessee under the following treatments: 1) Ambient CO2 pressure and air temperature (control); 2) CO2 pressure approximately 30 Pa above ambient; 3) Air temperatures 3 C above ambient; 4) Elevated CO2 and air temperature. Spectral reflectance, transmittance, and absorptance in the visible spectrum (400-720 nm) did not change significantly (rho = 0.05) in response to any treatment compared with control values. Although reflectance, transmittance, and absorptance at 700 nm correlated strongly with leaf chlorophyll content, chlorophyll content was not altered significantly by the treatments. The lack of treatment effects on pigmentation explained the non-significant change in optical properties in the visible spectrum. Optical properties in the near-infrared (721-850 nm) were similarly unresponsive to treatment with the exception of an increased absorptance in leaves that developed under elevated air temperature alone. This response could not be explained by the data, but might have resulted from effects of air temperature on leaf internal structure. Results indicated no significant potential for detecting leaf optical responses to elevated CO2 or temperature by the remote sensing of reflected radiation in the 400-850 nm spectrum.

  1. Leaf onset in the northern hemisphere triggered by daytime temperature

    PubMed Central

    Piao, Shilong; Tan, Jianguang; Chen, Anping; Fu, Yongshuo H.; Ciais, Philippe; Liu, Qiang; Janssens, Ivan A.; Vicca, Sara; Zeng, Zhenzhong; Jeong, Su-Jong; Li, Yue; Myneni, Ranga B.; Peng, Shushi; Shen, Miaogen; Peñuelas, Josep

    2015-01-01

    Recent warming significantly advanced leaf onset in the northern hemisphere. This signal cannot be accurately reproduced by current models parameterized by daily mean temperature (Tmean). Here using in situ observations of leaf unfolding dates (LUDs) in Europe and the United States, we show that the interannual anomalies of LUD during 1982–2011 are triggered by daytime (Tmax) more than by nighttime temperature (Tmin). Furthermore, an increase of 1 °C in Tmax would advance LUD by 4.7 days in Europe and 4.3 days in the United States, more than the conventional temperature sensitivity estimated from Tmean. The triggering role of Tmax, rather than the Tmin or Tmean variable, is also supported by analysis of the large-scale patterns of satellite-derived vegetation green-up in spring in the northern hemisphere (>30°N). Our results suggest a new conceptual framework of leaf onset using daytime temperature to improve the performance of phenology modules in current Earth system models. PMID:25903224

  2. Machine vision guided sensor positioning system for leaf temperature assessment

    NASA Technical Reports Server (NTRS)

    Kim, Y.; Ling, P. P.; Janes, H. W. (Principal Investigator)

    2001-01-01

    A sensor positioning system was developed for monitoring plants' well-being using a non-contact sensor. Image processing algorithms were developed to identify a target region on a plant leaf. A novel algorithm to recover view depth was developed by using a camera equipped with a computer-controlled zoom lens. The methodology has improved depth recovery resolution over a conventional monocular imaging technique. An algorithm was also developed to find a maximum enclosed circle on a leaf surface so the conical field-of-view of an infrared temperature sensor could be filled by the target without peripheral noise. The center of the enclosed circle and the estimated depth were used to define the sensor 3-D location for accurate plant temperature measurement.

  3. Cold air drainage and modeled nocturnal leaf water potential in complex forested terrain.

    PubMed

    Hubbart, Jason A; Kavanagh, Kathleen L; Pangle, Robert; Link, Tim; Schotzko, Alisa

    2007-04-01

    Spatial variation in microclimate caused by air temperature inversions plays an important role in determining the timing and rate of many physical and biophysical processes. Such phenomena are of particular interest in mountainous regions where complex physiographic terrain can greatly complicate these processes. Recent work has demonstrated that, in some plants, stomata do not close completely at night, resulting in nocturnal transpiration. The following work was undertaken to develop a better understanding of nocturnal cold air drainage and its subsequent impact on the reliability of predawn leaf water potential (Psi(pd)) as a surrogate for soil water potential (Psi(s)). Eight temperature data loggers were installed on a transect spanning a vertical distance of 155 m along a north facing slope in the Mica Creek Experimental Watershed (MCEW) in northern Idaho during July and August 2004. Results indicated strong nocturnal temperature inversions occurring from the low- to upper-mid-slope, typically spanning the lower 88 m of the vertical distance. Based on mean temperatures for both months, inversions resulted in lapse rates of 29.0, 27.0 and 25.0 degrees C km(-1) at 0000, 0400 and 2000 h, respectively. At this scale (i.e., < 1 km), the observed lapse rates resulted in highly variable nighttime vapor pressure deficits (D) over the length of the slope, with variable impacts on modeled disequilibrium between soil and leaf water potential. As a result of cold air drainage, modeled Psi(pd) became consistently more negative (up to -0.3 MPa) at higher elevations during the night based on mean temperatures. Nocturnal inversions on the lower- and mid-slopes resulted in leaf water potentials that were at least 30 and 50% more negative over the lower 88 m of the inversion layer, based on mean and maximum temperatures, respectively. However, on a cloudy night, with low D, the maximum decrease in Psi(pd) was -0.04 MPa. Our results indicate that, given persistent cold air

  4. 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.

  5. Emissions of H 2 and CO from leaf litter of Sequoiadendron giganteum , and their dependence on UV radiation and temperature

    NASA Astrophysics Data System (ADS)

    Derendorp, L.; Quist, J. B.; Holzinger, R.; Röckmann, T.

    2011-12-01

    Senescent and dead plant material releases carbon monoxide (CO), methane and higher hydrocarbons upon heating or irradiation with UV, but emissions of hydrogen (H 2) have not been reported. This study investigated whether leaf litter is able to emit H 2 and which factors control the possible emissions. In addition, the emission of CO from leaf litter was measured and compared to previous studies. H 2 was released from leaf litter of sequoia ( Sequoiadendron giganteum) in detectable amounts at temperatures above 45 °C, whereas CO was also emitted at ambient temperature. The emission rates of both H 2 and CO increased with temperature according to the Arrhenius relation. UV radiation can induce emissions of both H 2 and CO. However, UV induced H 2 was only emitted under anoxic conditions, while CO emissions were higher in synthetic air, but strongly reduced in absence of oxygen.

  6. 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

  7. The Relationship Between Air Temperature and Stream Temperature

    NASA Astrophysics Data System (ADS)

    Morrill, J. C.; Bales, R. C.; Conklin, M. H.

    2001-05-01

    This study examined the relationship, both linear and non-linear, between air temperature and stream temperature in order to determine if air temperature can be used as an accurate predictor of stream temperature, if general relationships could be developed that apply to a large number of streams, and how changes in stream temperature associated with climate variability or climate warming might affect the dissolved oxygen level, and thus the quality of life, in some of these streams. Understanding the relationship between air temperature and water temperature is important if we want to predict how stream temperatures are likely to respond to the increase in surface air temperature that is occurring. Data from over 50 streams in 13 countries, mostly gathered by K-12 students in the GLOBE program (Global Learning and Observations to Benefit the Environment), are examined. Only a few streams display a linear 1:1 air/water temperature trend. The majority of streams instead show an increase in water temperature of about 0.6 to 0.8 degrees for every 1-degree increase in air temperature. At some of these sites, where dissolved oxygen content is already low, an increase in summer stream temperatures of 2-3 degrees could cause the dissolved oxygen levels to fall into a critically low range. At some locations, such as near the source of a stream, water temperature does not change much despite wide ranges in air temperatures. The temperatures at these sites are likely to be least affected by surface warming. More data are needed in warmer climates, where the water temperature already gets above 25oC, in order to better examine the air/water temperature relationship under warmer conditions. Global average surface air temperature is expected to increase by 3-5oC by the middle of this century. Surface water temperature in streams, lakes and wetlands will likely increase as air temperature increases, although the change in water temperature may not be as large as the change in

  8. Temperature stress effects in Quercus suber leaf metabolism.

    PubMed

    Chaves, Inês; Passarinho, José António P; Capitão, Cláudio; Chaves, Maria Manuela; Fevereiro, Pedro; Ricardo, Cândido P P

    2011-10-15

    Based on projections that climate changes are will intensify in the near future, it is important to understand how plants respond to climate. Consequently, we have been studying the effect of contrasting temperatures on leaf metabolism of Quercus suber, an important Mediterranean oak. Potted plants were grown under controlled conditions for 53 days at 28°C or 10°C. The accumulation of major soluble metabolites was analyzed by NMR. The relative levels of transcripts of genes encoding key enzymes of the shikimate and phenylpropanoid pathway (CS, PAL, CAD and ChS) were examined by means of quantitative, real-time RT-PCR. At 10°C, in the pre-existing leaves, the concentrations of sucrose, quercitol and catechin were higher, as were PAL and ChS transcripts. At 28°C, however, it was the concentration of quinic acid that was higher, as were the concentrations of CS and CAD transcripts. We conclude that contrasting temperatures greatly influence Q. suber metabolism and that a deeper analysis of the effects of more extreme temperatures is needed to understand the possible effects of temperature changes on Q. suber metabolism and physiology.

  9. Leaf physiological responses of mature Norway Spruce trees exposed to elevated carbon dioxide and temperature

    NASA Astrophysics Data System (ADS)

    Lamba, Shubhangi; Uddling, Johan; Räntfors, Mats; Hall, Marianne; Wallin, Göran

    2014-05-01

    Leaf photosynthesis, respiration and stomatal conductance exert strong control over the exchange of carbon, water and energy between the terrestrial biosphere and the atmosphere. As such, leaf physiological responses to rising atmospheric CO2 concentration ([CO2]) and temperature have important implications for the global carbon cycle and rate of ongoing global warming, as well as for local and regional hydrology and evaporative cooling. It is therefore critical to improve the understanding of plant physiological responses to elevated [CO2] and temperature, in particular for boreal and tropical ecosystems. In order to do so, we examined physiological responses of mature boreal Norway spruce trees (ca 40-years old) exposed to elevated [CO2] and temperature inside whole-tree chambers at Flakaliden research site, Northern Sweden. The trees were exposed to a factorial combination of two levels of [CO2] (ambient and doubled) and temperature (ambient and +2.8 degree C in summer and +5.6 degree C in winter). Three replicates in each of the four treatments were used. It was found that photosynthesis was increased considerably in elevated [CO2], but was not affected by the warming treatment. The maximum rate of photosynthetic carboxylation was reduced in the combined elevated [CO2] and elevated temperature treatment, but not in single factor treatments. Elevated [CO2] also strongly increased the base rate of respiration and to a lesser extent reduced the temperature sensitivity (Q10 value) of respiration; responses which may be important for the carbon balance of these trees which have a large proportion of shaded foliage. Stomatal conductance at a given VPD was reduced by elevated temperature treatment, to a degree that mostly offset the higher vapour pressure deficit in warmed air with respect to transpiration. Elevated [CO2] did not affect stomatal conductance, and thus increased the ratio of leaf internal to external [CO2]. These results indicate that the large elevated

  10. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest.

    PubMed

    Jardine, Kolby J; Chambers, Jeffrey Q; Holm, Jennifer; Jardine, Angela B; Fontes, Clarissa G; Zorzanelli, Raquel F; Meyers, Kimberly T; de Souza, Vinicius Fernadez; Garcia, Sabrina; Gimenez, Bruno O; Piva, Luani R de O; Higuchi, Niro; Artaxo, Paulo; Martin, Scot; Manzi, Antônio O

    2015-09-15

    Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C₅ and C₆ GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C₆ GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

  11. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

    PubMed Central

    Jardine, Kolby J.; Chambers, Jeffrey Q.; Holm, Jennifer; Jardine, Angela B.; Fontes, Clarissa G.; Zorzanelli, Raquel F.; Meyers, Kimberly T.; de Souza, Vinicius Fernadez; Garcia, Sabrina; Gimenez, Bruno O.; de O. Piva, Luani R.; Higuchi, Niro; Artaxo, Paulo; Martin, Scot; Manzi, Antônio O.

    2015-01-01

    Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress. PMID:27135346

  12. 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.

  13. 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.

  14. Patterns of leaf morphology and leaf N content in relation to winter temperatures in three evergreen tree species.

    PubMed

    Mediavilla, Sonia; Gallardo-López, Victoria; González-Zurdo, Patricia; Escudero, Alfonso

    2012-09-01

    The competitive equilibrium between deciduous and perennial species in a new scenario of climate change may depend closely on the productivity of leaves along the different seasons of the year and on the morphological and chemical adaptations required for leaf survival during the different seasons. The aim of the present work was to analyze such adaptations in the leaves of three evergreen species (Quercus ilex, Q. suber and Pinus pinaster) and their responses to between-site differences in the intensity of winter harshness. We explore the hypothesis that the harshness of winter would contribute to enhancing the leaf traits that allow them to persist under conditions of stress. The results revealed that as winter harshness increases a decrease in leaf size occurs in all three species, together with an increase in the content of nitrogen per unit leaf area and a greater leaf mass per unit area, which seems to be achieved only through increased thickness, with no associated changes in density. P. pinaster was the species with the most intense response to the harshening of winter conditions, undergoing a more marked thickening of its needles than the two Quercus species. Our findings thus suggest that lower winter temperatures involve an increase in the cost of leaf production of evergreen species, which must be taken into account in the estimation of the final cost and benefit balance of evergreens. Such cost increases would be more pronounced for those species that, like P. pinaster, show a stronger response to the winter cold.

  15. Patterns of leaf morphology and leaf N content in relation to winter temperatures in three evergreen tree species

    NASA Astrophysics Data System (ADS)

    Mediavilla, Sonia; Gallardo-López, Victoria; González-Zurdo, Patricia; Escudero, Alfonso

    2012-09-01

    The competitive equilibrium between deciduous and perennial species in a new scenario of climate change may depend closely on the productivity of leaves along the different seasons of the year and on the morphological and chemical adaptations required for leaf survival during the different seasons. The aim of the present work was to analyze such adaptations in the leaves of three evergreen species ( Quercus ilex, Q. suber and Pinus pinaster) and their responses to between-site differences in the intensity of winter harshness. We explore the hypothesis that the harshness of winter would contribute to enhancing the leaf traits that allow them to persist under conditions of stress. The results revealed that as winter harshness increases a decrease in leaf size occurs in all three species, together with an increase in the content of nitrogen per unit leaf area and a greater leaf mass per unit area, which seems to be achieved only through increased thickness, with no associated changes in density. P. pinaster was the species with the most intense response to the harshening of winter conditions, undergoing a more marked thickening of its needles than the two Quercus species. Our findings thus suggest that lower winter temperatures involve an increase in the cost of leaf production of evergreen species, which must be taken into account in the estimation of the final cost and benefit balance of evergreens. Such cost increases would be more pronounced for those species that, like P. pinaster, show a stronger response to the winter cold.

  16. Temperature affects leaf litter decomposition in low-order forest streams: field and microcosm approaches.

    PubMed

    Martínez, Aingeru; Larrañaga, Aitor; Pérez, Javier; Descals, Enrique; Pozo, Jesús

    2014-01-01

    Despite predicted global warming, the temperature effects on headwater stream functioning are poorly understood. We studied these effects on microbial-mediated leaf decomposition and the performance of associated aquatic hyphomycete assemblages. Alder leaves were incubated in three streams differing in winter water temperature. Simultaneously, in laboratory, leaf discs conditioned in these streams were incubated at 5, 10 and 15 °C. We determined mass loss, leaf N and sporulation rate and diversity of aquatic hyphomycete communities. In the field, decomposition rate correlated positively with temperature. Decomposition rate and leaf N presented a positive trend with dissolved nutrients, suggesting that temperature was not the only factor determining the process velocity. Under controlled conditions, it was confirmed that decomposition rate and leaf N were positively correlated with temperature, leaves from the coldest stream responding most clearly. Sporulation rate correlated positively with temperature after 9 days of incubation, but negatively after 18 and 27 days. Temperature rise affected negatively the sporulating fungi richness and diversity only in the material from the coldest stream. Our results suggest that temperature is an important factor determining leaf processing and aquatic hyphomycete assemblages and that composition and activity of fungal communities adapted to cold environments could be more affected by temperature rises. Highlight: Leaf decomposition rate and associated fungal communities respond to temperature shifts in headwater streams.

  17. Leaf ontogeny strongly influences photosynthetic tolerance to drought and high temperature in Gossypium hirsutum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperature and drought are major abiotic limitations to crop productivity worldwide. While abiotic stress physiology research has focused primarily on fully expanded leaves, no studies have investigated photosynthetic tolerance to concurrent drought and high temperature during leaf ontogeny. To add...

  18. Leaf photosynthetic and water-relations responses for 'Valencia' orange trees exposed to oxidant air pollution

    SciTech Connect

    Olszyk, D.M.; Takemoto, B.K.; Poe, M.

    1991-01-01

    Leaf responses were measured to test a hypothesis that reduced photosynthetic capacity and/or altered water relations were associated with reductions in yield for 'Valencia' orange trees (Citrus sinensis (L.), Osbeck) exposed to ambient oxidant air pollution. Exposures were continuous for 4 years to three levels of oxidants (in charcoal-filtered, half-filtered, and non-filtered air). Oxidants had no effect on net leaf photosynthetic rates or on photosynthetic pigment concentrations. A single set of measurements indicated that oxidants increased leaf starch concentrations (24%) prior to flowering, suggesting a change in photosynthate allocation. Leaves exposed to oxidants had small, but consistent, changes in water relations over the summer growing season, compared to trees growing in filtered air. Other changes included decreased stomatal conductance (12%) and transpiration (9%) rates, and increased water pressure potentials (5%). While all responses were subtle, their cumulative impact over 4 years indicated that 'Valencia' orange trees were subject to increased ambient oxidant stress.

  19. 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.

  20. Air Temperature in the Undulator Hall

    SciTech Connect

    Not Available

    2010-12-07

    Various analyses have been performed recently to estimate the performance of the air conditioning (HVAC) system planned for the Undulator Hall. This reports summarizes the results and provides an upgrade plan to be used if new requirements are needed in the future. The estimates predict that with the planned loads the tunnel air temperature will be well within the allowed tolerance during normal operation.

  1. Characterization of Leaf Blade- and Leaf Sheath-Associated Bacterial Communities and Assessment of Their Responses to Environmental Changes in CO2, Temperature, and Nitrogen Levels under Field Conditions

    PubMed Central

    Ikeda, Seishi; Tokida, Takeshi; Nakamura, Hirofumi; Sakai, Hidemitsu; Usui, Yasuhiro; Okubo, Takashi; Tago, Kanako; Hayashi, Kentaro; Sekiyama, Yasuyo; Ono, Hiroshi; Tomita, Satoru; Hayatsu, Masahito; Hasegawa, Toshihiro; Minamisawa, Kiwamu

    2015-01-01

    Rice shoot-associated bacterial communities at the panicle initiation stage were characterized and their responses to elevated surface water-soil temperature (ET), low nitrogen (LN), and free-air CO2 enrichment (FACE) were assessed by clone library analyses of the 16S rRNA gene. Principal coordinate analyses combining all sequence data for leaf blade- and leaf sheath-associated bacteria revealed that each bacterial community had a distinct structure, as supported by PC1 (61.5%), that was mainly attributed to the high abundance of Planctomycetes in leaf sheaths. Our results also indicated that the community structures of leaf blade-associated bacteria were more sensitive than those of leaf sheath-associated bacteria to the environmental factors examined. Among these environmental factors, LN strongly affected the community structures of leaf blade-associated bacteria by increasing the relative abundance of Bacilli. The most significant effect of FACE was also observed on leaf blade-associated bacteria under the LN condition, which was explained by decreases and increases in Agrobacterium and Pantoea, respectively. The community structures of leaf blade-associated bacteria under the combination of FACE and ET were more similar to those of the control than to those under ET or FACE. Thus, the combined effects of environmental factors need to be considered in order to realistically assess the effects of environmental changes on microbial community structures. PMID:25740174

  2. 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

  3. 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

  4. Growth temperature modulates the spatial variability of leaf morphology and chemical elements within crowns of climatically divergent Acer rubrum genotypes.

    PubMed

    Shahba, Mohamed A; Bauerle, William L

    2009-07-01

    Our understanding of leaf acclimation in relation to temperature of fully grown or juvenile tree crowns is mainly based on research involving spatially uncontrolled growth temperature. In this study, we test the hypothesis that leaf morphology and chemical elements are modulated by within-crown growth temperature differences. We ask whether within-species variation can influence acclimation to elevated temperatures. Within-crown temperature dependence of leaf morphology, carbon and nitrogen was examined in two genotypes of Acer rubrum L. (red maple) from different latitudes, where the mean annual temperature varies between 7.2 and 19.4 degrees C. Crown sections were grown in temperature-controlled chambers at three daytime growth temperatures (25, 33 and 38 degrees C). Leaf growth and resource acquisition were measured at regular intervals over long-term (50 days) controlled daytime growth temperatures. We found significant intraspecific variation in temperature dependence of leaf carbon and nitrogen accumulation between genotypes. Additionally, there was evidence that leaf morphology depended on inherited adaptation. Leaf dry matter and nitrogen content decreased as growth temperature was elevated above 25 degrees C in the genotype native to the cooler climate, whereas they remained fairly constant in response to temperature in the genotype native to the warmer climate. Specific leaf area (SLA) was correlated positively to leaf nitrogen content in both genotypes. The SLA and the relative leaf dry matter content (LM), on the other hand, were correlated negatively to leaf thickness. However, intraspecific variation in SLA and LM versus leaf thickness was highly significant. Intraspecific differences in leaf temperature response between climatically divergent genotypes yielded important implications for convergent evolution of leaf adaptation. Comparison of our results with those of previous studies showed that leaf carbon allocation along a vertical temperature

  5. 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.

  6. How the Plant Temperature Links to the Air Temperature in the Desert Plant Artemisia ordosica.

    PubMed

    Yu, Ming-Han; Ding, Guo-Dong; Gao, Guang-Lei; Sun, Bao-Ping; Zhao, Yuan-Yuan; Wan, Li; Wang, De-Ying; Gui, Zi-Yang

    2015-01-01

    Plant temperature (Tp) is an important indicator of plant health. To determine the dynamics of plant temperature and self-cooling ability of the plant, we measured Tp in Artemisia ordosica in July, in the Mu Us Desert of Northwest China. Related factors were also monitored to investigate their effects on Tp, including environmental factors, such as air temperature (Ta), relative humidity, wind speed; and physiological factors, such as leaf water potential, sap flow, and water content. The results indicate that: 1) Tp generally changes in conjunction with Ta mainly, and varies with height and among the plant organs. Tp in the young branches is most constant, while it is the most sensitive in the leaves. 2) Correlations between Tp and environmental factors show that Tp is affected mainly by Ta. 3) The self-cooling ability of the plant was effective by midday, with Tp being lower than Ta. 4) Increasing sap flow and leaf water potential showed that transpiration formed part of the mechanism that supported self-cooling. Increased in water conductance and specific heat at midday may be additional factors that contribute to plant cooling ability. Therefore, our results confirmed plant self-cooling ability. The response to high temperatures is regulated by both transpiration speed and an increase in stem water conductance. This study provides quantitative data for plant management in terms of temperature control. Moreover, our findings will assist species selection with taking plant temperature as an index.

  7. DEVELOPMENT OF AN AIR-TO-LEAF VAPOR PHASE TRANSFER FACTOR FOR DIOXINS AND FURANS

    EPA Science Inventory

    Results of an experiment in which grass was grown in a greenhouse and outdoors, and in soils of different concentration levels of dioxins and furans, were used in a modeling exercise to derive an air-to-leaf vapor phase transfer factor. The purpose of the experiment was to under...

  8. 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.

  9. 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.

  10. Modeling of global surface air temperature

    NASA Astrophysics Data System (ADS)

    Gusakova, M. A.; Karlin, L. N.

    2012-04-01

    A model to assess a number of factors, such as total solar irradiance, albedo, greenhouse gases and water vapor, affecting climate change has been developed on the basis of Earth's radiation balance principle. To develop the model solar energy transformation in the atmosphere was investigated. It's a common knowledge, that part of the incoming radiation is reflected into space from the atmosphere, land and water surfaces, and another part is absorbed by the Earth's surface. Some part of outdoing terrestrial radiation is retained in the atmosphere by greenhouse gases (carbon dioxide, methane, nitrous oxide) and water vapor. Making use of the regression analysis a correlation between concentration of greenhouse gases, water vapor and global surface air temperature was obtained which, it is turn, made it possible to develop the proposed model. The model showed that even smallest fluctuations of total solar irradiance intensify both positive and negative feedback which give rise to considerable changes in global surface air temperature. The model was used both to reconstruct the global surface air temperature for the 1981-2005 period and to predict global surface air temperature until 2030. The reconstructions of global surface air temperature for 1981-2005 showed the models validity. The model makes it possible to assess contribution of the factors listed above in climate change.

  11. Leaf shape responds to temperature but not CO2 in Acer rubrum.

    PubMed

    Royer, Dana L

    2012-01-01

    The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT) across many plant communities. These relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO(2) concentration affects leaf shape, limiting confidence in ancient climate reconstructions because CO(2) has varied widely on geologic timescales. Here I report the results of growing Acer rubrum (red maple) in growth cabinets at contrasting temperature and CO(2) conditions. The CO(2) treatment imparted no significant differences in leaf size and shape, while plants grown at cooler temperatures tended to have more teeth and more highly dissected leaves. These results provide direct evidence for the selection of temperature on leaf shape in one species, and support a key link in many leaf-climate methods. More broadly, these results increase confidence for using leaf shape in fossils to reconstruct paleoclimate.

  12. AIRS Retrieved Temperature Isotherms over Southern Europe

    NASA Technical Reports Server (NTRS)

    2002-01-01

    AIRS Retrieved Temperature Isotherms over Southern Europe viewed from the west, September 8, 2002. The isotherms in this map made from AIRS data show regions of the same temperature in the atmosphere.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  13. Ozone concentration in leaf intercellular air spaces is close to zero

    SciTech Connect

    Laisk, A.; Moldau, H. ); Kull, O. )

    1989-07-01

    Transpiration and ozone uptake rates were measured simultaneously in sunflower leaves at different stomatal openings and various ozone concentrations. Ozone uptake rates were proportional to the ozone concentration up to 1500 nanoliters per liter. The leaf gas phase diffusion resistance (stomatal plus boundary layer) to water vapor was calculated and converted to the resistance to ozone multiplying it by the theoretical ratio of diffusion coefficients for water vapor and ozone in air (1.67). The ozone concentration in intercellular air spaces calculated from the ozone uptake rate and diffusion resistance to ozone scattered around zero. The ozone concentration in intercellular air spaces was measured directly bu supplying ozone to the leaf from one side and measuring the equilibrium concentration above the other side, and it was found to be zero. The total leaf resistance to ozone was proportional to the gas phase resistance to water vapor with a coefficient of 1.68. It is concluded that ozone enters the leaf by diffusion through the stomata, and is rapidly decomposed in cell walls and plasmalemma.

  14. Ozone Concentration in Leaf Intercellular Air Spaces Is Close to Zero 1

    PubMed Central

    Laisk, Agu; Kull, Olevi; Moldau, Heino

    1989-01-01

    Transpiration and ozone uptake rates were measured simultaneously in sunflower leaves at different stomatal openings and various ozone concentrations. Ozone uptake rates were proportional to the ozone concentration up to 1500 nanoliters per liter. The leaf gas phase diffusion resistance (stomatal plus boundary layer) to water vapor was calculated and converted to the resistance to ozone multiplying it by the theoretical ratio of diffusion coefficients for water vapor and ozone in air (1.67). The ozone concentration in intercellular air spaces calculated from the ozone uptake rate and diffusion resistance to ozone scattered around zero. The ozone concentration in intercellular air spaces was measured directly by supplying ozone to the leaf from one side and measuring the equilibrium concentration above the other side, and it was found to be zero. The total leaf resistance to ozone was proportional to the gas phase resistance to water vapor with a coefficient of 1.68. It is concluded that ozone enters the leaf by diffusion through the stomata, and is rapidly decomposed in cell walls and plasmalemma. PMID:16666867

  15. Leaf architectural, vascular and photosynthetic acclimation to temperature in two biennials.

    PubMed

    Muller, Onno; Stewart, Jared J; Cohu, Christopher M; Polutchko, Stephanie K; Demmig-Adams, Barbara; Adams, William W

    2014-12-01

    Acclimation of leaf features to growth temperature was investigated in two biennials (whose life cycle spans summer and winter seasons) using different mechanisms of sugar loading into exporting conduits, Verbascum phoeniceum (employs sugar-synthesizing enzymes driving symplastic loading through plasmodesmatal wall pores of phloem cells) and Malva neglecta (likely apoplastic loader transporting sugar via membrane transport proteins of phloem cells). In both species, acclimation to lower temperature involved greater maximal photosynthesis rates and vein density per leaf area in close correlation with modification of minor vein cellular features. While the symplastically loading biennial exhibited adjustments in the size of minor leaf vein cells (consistent with adjustment of the level of sugar-synthesizing enzymes), the putative apoplastic biennial exhibited adjustments in the number of cells (consistent with adjustment of cell membrane area for transporter placement). This upregulation of morphological and anatomical features at lower growth temperature likely contributes to the success of both the species during the winter. Furthermore, while acclimation to low temperature involved greater leaf mass per area in both species, this resulted from greater leaf thickness in V. phoeniceum vs a greater number of mesophyll cells per leaf area in M. neglecta. Both types of adjustments presumably accommodate more chloroplasts per leaf area contributing to photosynthesis. Both biennials exhibited high foliar vein densities (particularly the solar-tracking M. neglecta), which should aid both sugar export from and delivery of water to the leaves.

  16. 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...

  17. 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...

  18. 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...

  19. Impact of elevated temperatures on specific leaf weight, stomatal density, photosynthesis and chlorophyll fluorescence in soybean.

    PubMed

    Jumrani, Kanchan; Bhatia, Virender Singh; Pandey, Govind Prakash

    2017-03-01

    High-temperature stress is a major environmental stress and there are limited studies elucidating its impact on soybean (Glycine max L. Merril.). The objectives of present study were to quantify the effect of high temperature on changes in leaf thickness, number of stomata on adaxial and abaxial leaf surfaces, gas exchange, chlorophyll fluorescence parameters and seed yield in soybean. Twelve soybean genotypes were grown at day/night temperatures of 30/22, 34/24, 38/26 and 42/28 °C with an average temperature of 26, 29, 32 and 35 °C, respectively, under greenhouse conditions. One set was also grown under ambient temperature conditions where crop season average maximum, minimum and mean temperatures were 28.0, 22.4 and 25.2 °C, respectively. Significant negative effect of temperature was observed on specific leaf weight (SLW) and leaf thickness. Rate of photosynthesis, stomatal conductance and water use efficiency declined as the growing temperatures increased; whereas, intercellular CO2 and transpiration rate were increased. With the increase in temperature chlorophyll fluorescence parameters such as Fv/Fm, qP and PhiPSII declined while there was increase in qN. Number of stomata on both abaxial and adaxial surface of leaf increased significantly with increase in temperatures. The rate of photosynthesis, PhiPSII, qP and SPAD values were positively associated with leaf thickness and SLW. This indicated that reduction in photosynthesis and associated parameters appears to be due to structural changes observed at higher temperatures. The average seed yield was maximum (13.2 g/pl) in plants grown under ambient temperature condition and declined by 8, 14, 51 and 65% as the temperature was increased to 30/22, 34/24, 38/26 and 42/28 °C, respectively.

  20. KINETICS OF LEAF TEMPERATURE FLUCTUATION AFFECT ISOPRENE EMISSION FROM RED OAK (QUERCUS RUBRA) LEAVES

    EPA Science Inventory

    Because the rate of isoprene (2-methyl-1,3-butadiene) emission from plants is highly temperature-dependent, we investigated the natural fluctuations on leaf temperature and the effects of rapid temperature change on isoprene emission of red oak (Quercus rubra L.) leaves at the to...

  1. Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests.

    PubMed

    Bothwell, Lori D; Selmants, Paul C; Giardina, Christian P; Litton, Creighton M

    2014-01-01

    Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivity of leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical montane wet forests where the warming trend may be amplified compared to tropical wet forests at lower elevations. We quantified leaf litter decomposition rates along a highly constrained 5.2 °C mean annual temperature (MAT) gradient in tropical montane wet forests on the Island of Hawaii. Dominant vegetation, substrate type and age, soil moisture, and disturbance history are all nearly constant across this gradient, allowing us to isolate the effect of rising MAT on leaf litter decomposition and nutrient release. Leaf litter decomposition rates were a positive linear function of MAT, causing the residence time of leaf litter on the forest floor to decline by ∼31 days for each 1 °C increase in MAT. Our estimate of the Q 10 temperature coefficient for leaf litter decomposition was 2.17, within the commonly reported range for heterotrophic organic matter decomposition (1.5-2.5) across a broad range of ecosystems. The percentage of leaf litter nitrogen (N) remaining after six months declined linearly with increasing MAT from ∼88% of initial N at the coolest site to ∼74% at the warmest site. The lack of net N immobilization during all three litter collection periods at all MAT plots indicates that N was not limiting to leaf litter decomposition, regardless of temperature. These results suggest that leaf litter decay in tropical montane wet forests may be more sensitive to rising MAT than in tropical lowland wet forests, and that increased rates of N release from decomposing litter could delay or prevent progressive N limitation to net primary productivity with climate warming.

  2. The potential of biomonitoring of air quality using leaf characteristics of white willow (Salix alba L.).

    PubMed

    Wuytack, Tatiana; Verheyen, Kris; Wuyts, Karen; Kardel, Fatemeh; Adriaenssens, Sandy; Samson, Roeland

    2010-12-01

    In this study, we assess the potential of white willow (Salix alba L.) as bioindicator for monitoring of air quality. Therefore, shoot biomass, specific leaf area, stomatal density, stomatal pore surface, and stomatal resistance were assessed from leaves of stem cuttings. The stem cuttings were introduced in two regions in Belgium with a relatively high and a relatively low level of air pollution, i.e., Antwerp city and Zoersel, respectively. In each of these regions, nine sampling points were selected. At each sampling point, three stem cuttings of white willow were planted in potting soil. Shoot biomass and specific leaf area were not significantly different between Antwerp city and Zoersel. Microclimatic differences between the sampling points may have been more important to plant growth than differences in air quality. However, stomatal pore surface and stomatal resistance of white willow were significantly different between Zoersel and Antwerp city. Stomatal pore surface was 20% lower in Antwerp city due to a significant reduction in both stomatal length (-11%) and stomatal width (-14%). Stomatal resistance at the adaxial leaf surface was 17% higher in Antwerp city because of the reduction in stomatal pore surface. Based on these results, we conclude that stomatal characteristics of white willow are potentially useful indicators for air quality.

  3. A novel method for air drying aloe leaf slices by covering with filter papers as a shrink-proof layer.

    PubMed

    Kim, S A; Baek, J H; Lee, S J; Choi, S Y; Hur, W; Lee, S Y

    2009-01-01

    To prevent the shrinkage of aloe vera slices during air drying, a method utilizing a shrink-proof layer was developed. The sample was configured of whole leaf aloe slices, where 1 side or both sides were covered with filter papers as shrink-proof layers. After air drying by varying the air temperature and the slice thickness, the drying characteristics, as well as several quality factors of the dried aloe vera leaf slices, were analyzed. In the simulation of the drying curves, the modified Page model showed the best fitness, representing a diffusion-controlled drying mechanism. Nonetheless, there was a trace of a constant-rate drying period in the samples dried by the method. Shrinkage was greatly reduced, and the rehydration ratios increased by approximately 50%. Scanning electron microscopic analysis revealed that the surface structure of original fibrous form was well sustained. FT-IR characteristics showed that the dried samples could sustain aloe polysaccharide acetylation. Furthermore, the functional properties of the dried slices including water holding capacity, swelling, and fat absorption capability were improved, and polysaccharide retention levels increased by 20% to 30%. Therefore, we concluded that application of shrink-proof layers on aloe slices provides a novel way to overcome the shrinkage problems commonly found in air drying, thereby improving their functional properties with less cost. Practical Application: This research article demonstrates a novel air drying method using shrink-proof layers to prevent the shrinkage of aloe slices. We analyzed extensively the characteristics of shrinkage mechanism and physical properties of aloe flesh gels in this drying system. We concluded that this method can be a beneficial means to retain the functional properties of dried aloe, and a potential alternative to freeze drying, which is still costly.

  4. Modeling air temperature changes in Northern Asia

    NASA Astrophysics Data System (ADS)

    Onuchin, A.; Korets, M.; Shvidenko, A.; Burenina, T.; Musokhranova, A.

    2014-11-01

    Based on time series (1950-2005) of monthly temperatures from 73 weather stations in Northern Asia (limited by 70-180° EL and 48-75° NL), it is shown that there are statistically significant spatial differences in character and intensity of the monthly and yearly temperature trends. These differences are defined by geomorphological and geographical parameters of the area including exposure of the territory to Arctic and Pacific air mass, geographic coordinates, elevation, and distances to Arctic and Pacific oceans. Study area has been divided into six domains with unique groupings of the temperature trends based on cluster analysis. An original methodology for mapping of temperature trends has been developed and applied to the region. The assessment of spatial patterns of temperature trends at the regional level requires consideration of specific regional features in the complex of factors operating in the atmosphere-hydrosphere-lithosphere-biosphere system.

  5. Co-ordination between Leaf Initiation and Leaf Appearance in Field-grown Maize (Zea mays): Genotypic Differences in Response of Rates to Temperature

    PubMed Central

    PADILLA, J. M.; OTEGUI, M. E.

    2005-01-01

    • Background and Aims In maize (Zea mays), early flowering date, which is a valuable trait for several cropping systems, is associated with the number of leaves per plant and the leaf appearance rate. Final leaf number depends upon the rate and duration of leaf initiation. The aims of this study were to analyse the genotypic variation in the response to temperature of leaf appearance rate and leaf initiation rate, and to investigate the co-ordination between these processes under field conditions. • Methods Sixteen hybrids of different origins were grown under six contrasting environmental conditions. The number of appeared leaves was measured twice a week to estimate leaf appearance rate (leaves d−1). Plants were dissected at four sampling dates to determine the number of initiated leaves and estimate leaf initiation rate (leaves d−1). A co-ordination model was fitted between the number of initiated leaves and the number of appeared leaves. This model was validated using two independent data sets. • Key Results Significant (P < 0·05) differences were found among hybrids in the response to temperature of leaf initiation rate (plastochron) and leaf appearance rate (phyllochron). Plastochron ranged between 24·3 and 36·4 degree days (°Cd), with a base temperature (Tb) between 4·0 and 8·2 °C. Phyllochron ranged between 48·6 and 65·5 °Cd, with a Tb between 2·9 and 5·0 °C. A single co-ordination model was fitted between the two processes for all hybrids and environments (r2 = 0·96, P < 0·0001), and was successfully validated (coefficient of variation < 9 %). • Conclusions This work has established the existence of genotypic variability in leaf initiation rate and leaf appearance rate in response to temperature, which is a promising result for maize breeding; and the interdependence between these processes from seedling emergence up to floral initiation. PMID:16126778

  6. Global surface air temperatures - Update through 1987

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lebedeff, Sergej

    1988-01-01

    Data from meteorological stations show that surface air temperatures in the 1980s are the warmest in the history of instrumental records. The four warmest years on record are all in the 1980s, with the warmest years in the analysis being 1981 and 1987. The rate of warming between the mid-1960s and the present is higher than that which occurrred in the previous period of rapid warming between the 1880s and 1940.

  7. Global trends of measured surface air temperature

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lebedeff, Sergej

    1987-01-01

    The paper presents the results of surface air temperature measurements from available meteorological stations for the period of 1880-1985. It is shown that the network of meteorological stations is sufficient to yield reliable long-term, decadal, and interannual temperature changes for both the Northern Hemisphere and the Southern Hemisphere, despite the fact that most stations are located on the continents. The results indicate a global warming of about 0.5-0.7 C in the past century, with warming of similar magnitude in both hemispheres. A strong warming trend between 1965 and 1980 raised the global mean temperature in 1980 and 1981 to the highest level in the period of instrumental records. Selected graphs of the temperature change in each of the eight latitude zones are included.

  8. Dry deposition of acidic air pollutants to tree leaves, determined by a modified leaf-washing technique

    NASA Astrophysics Data System (ADS)

    Watanabe, Mirai; Takamatsu, Takejiro; Koshikawa, Masami K.; Yamamura, Shigeki; Inubushi, Kazuyuki

    Dry deposition fluxes ( FL) of NO 3- and SO 42- to leaf surfaces were measured for Japanese red pine ( Pinus densiflora), Japanese cedar ( Cryptomeria japonica), Japanese cypress ( Chamaecyparis obtusa), and Japanese white oak ( Quercus myrsinaefolia), together with atmospheric concentrations ( CL) of NO x (NO + NO 2), T-NO 3 (gaseous HNO 3 + particulate NO 3-) and SO x (gaseous SO 2 + particulate SO 42-) around the leaves in a suburban area of Japan, using a modified leaf-washing technique. FL of NO 3- and SO 42- decreased as follows: pine >> cedar > cypress ≥ oak and pine >> cedar > oak ≥ cypress, respectively. FL of NO 3- for all tree species fluctuated synchronously with CL of T-NO 3. FL of SO 42- fluctuated with CL of SO x, but the dominant pollutant deposited (SO 2 or SO 42-) appeared to differ for different tree species. Dry deposition conductance ( KL) of T-NO 3 and SO x was derived as an FL/ CL ratio. Seasonal variations of KL likely reflect the gas/particle ratios of T-NO 3 and SO x, which were affected by meteorological conditions such as temperature. Dry deposition velocities ( Vd) of T-NO 3 and SO x were obtained as the mathematical product of annual mean KL and the total leaf surface areas in the forests. The comparison of Vd among tree species indicated that the loads of acidic air pollutants were higher to coniferous forests than broad-leaved forest because of the higher KL and/or larger leaf surface areas.

  9. Temperature Dependence of Lithium Reactions with Air

    NASA Astrophysics Data System (ADS)

    Sherrod, Roman; Skinner, C. H.; Koel, Bruce

    2016-10-01

    Liquid lithium plasma facing components (PFCs) are being developed to handle long pulse, high heat loads in tokamaks. Wetting by lithium of its container is essential for this application, but can be hindered by lithium oxidation by residual gases or during tokamak maintenance. Lithium PFCs will experience elevated temperatures due to plasma heat flux. This work presents measurements of lithium reactions at elevated temperatures (298-373 K) when exposed to natural air. Cylindrical TZM wells 300 microns deep with 1 cm2 surface area were filled with metallic lithium in a glovebox containing argon with less than 1.6 ppm H20, O2, and N2. The wells were transferred to a hot plate in air, and then removed periodically for mass gain measurements. Changes in the surface topography were recorded with a microscope. The mass gain of the samples at elevated temperatures followed a markedly different behavior to that at room temperature. One sample at 373 K began turning red indicative of lithium nitride, while a second turned white indicative of lithium carbonate formation. Data on the mass gain vs. temperature and associated topographic changes of the surface will be presented. Science Undergraduate Laboratory Internship funded by Department of Energy.

  10. Leaf margins and temperature in the North American flora: Recalibrating the paleoclimatic thermometer

    NASA Astrophysics Data System (ADS)

    Adams, J. M.; Green, W. A.; Zhang, Y.

    2008-02-01

    For almost a century, leaf margin analysis has been an important method of estimating Cenozoic paleotemperatures. However, the relation between the proportion of toothed versus entire leaves and temperature has so far been calibrated and characterized using relatively small numbers of opportunistically and irregularly collected floras. Here we present the results of the first systematic spatially-distributed analysis of the relation between leaf margins and temperature for North America. We used species range maps of native North American dicot trees to derive synthetic local floras for each 50 km grid cell in the USA and Canada, and compared the percentage of entire-margined species with the mean annual temperature in each cell. Leaf margin type for each species was assigned using illustrations from appropriate regional North America floras. This analysis confirms that high-rainfall areas of the eastern USA and Canada show a strong inverse relationship between toothed margin percentage and mean annual temperature in the range 0-25 °C. The values we estimate are roughly similar to those obtained from floras in east Asia and previous analyses in North America, but the detailed curve is more complex, showing a distinct change in slope above a mean annual temperature of 20 °C. Wetter climate areas of the coastal western USA do not show any significant correlation between leaf margin percentage and temperature. This may relate to the confounding effect of the diverse topography of the West Coast, or it may be caused by the depleted dicotyledonous tree flora of this area. Like previous studies, this paper demonstrates that there indeed is a strong relationship between leaf margin percentage and temperature on a regional scale in eastern North America. However the relationship does not have the same linear behavior as results obtained from previous analyses. We discuss the implications of the results obtained here for paleoclimatic reconstruction in the content of

  11. Modeling light and temperature effects on leaf emergence in wheat and barley

    NASA Technical Reports Server (NTRS)

    Volk, T.; Bugbee, B.

    1991-01-01

    Phenological development affects canopy structure, radiation interception, and dry matter production; most crop simulation models therefore incorporate leaf emergence rate as a basic parameter. A recent study examined leaf emergence rate as a function of temperature and daylength among wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) cultivars. Leaf emergence rate and phyllochron were modeled as functions of temperature alone, daylength alone, and the interaction between temperature and daylength. The resulting equations contained an unwieldy number of constants. Here we simplify by reducing the constants by > 70%, and show leaf emergence rate as a single response surface with temperature and daylength. In addition, we incorporate the effect of photosynthetic photon flux into the model. Generic fits for wheat and barley show cultivar differences less than +/- 5% for wheat and less than +/- 10% for barley. Barley is more sensitive to daylength changes than wheat for common environmental values of daylength, which may be related to the difference in sensitivity to daylength between spring and winter cultivars. Differences in leaf emergence rate between cultivars can be incorporated into the model by means of a single, nondimensional factor for each cultivar.

  12. Establishment of the chloroplast genetic system in rice during early leaf development and at low temperatures

    PubMed Central

    Kusumi, Kensuke; Iba, Koh

    2014-01-01

    Chloroplasts are the central nodes of the metabolic network in leaf cells of higher plants, and the conversion of proplastids into chloroplasts is tightly coupled to leaf development. During early leaf development, the structure and function of the chloroplasts differ greatly from those in a mature leaf, suggesting the existence of a stage-specific mechanism regulating chloroplast development during this period. Here, we discuss the identification of the genes affected in low temperature-conditional mutants of rice (Oryza sativa). These genes encode factors involved in chloroplast rRNA regulation (NUS1), and nucleotide metabolism in mitochondria, chloroplasts, and cytosol (V2, V3, ST1). These genes are all preferentially expressed in the early leaf developmental stage P4, and depleting them causes altered chloroplast transcription and translation, and ultimately leaf chlorosis. Therefore, it is suggested that regulation of cellular nucleotide pools and nucleotide metabolism is indispensable for chloroplast development under low temperatures at this stage. This review summarizes the current understanding of these factors and discusses their roles in chloroplast biogenesis. PMID:25157260

  13. Phenotypic Plasticity of Leaf Shape along a Temperature Gradient in Acer rubrum

    PubMed Central

    Royer, Dana L.; Meyerson, Laura A.; Robertson, Kevin M.; Adams, Jonathan M.

    2009-01-01

    Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables. PMID:19893620

  14. 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.

  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. [Effects of high temperature and humidity on leaf Bt protein expression of transgenic Bt cotton].

    PubMed

    Zhang, Xiang; Wang, Gui-Xia; Gu, Chao; Han, Yong; Xu, Ying-Fei; Chen, Yuan; Chen, De-Hua

    2012-11-01

    Different origins Bt cotton cultivars, including DP410B (conventional cultivar) and Daiza No. 1 (hybridized cultivar) from US and Sikang No. 1 (conventional cultivar) and Sikang No. 3 (hybridized cultivar) from China, were taken as the test materials to investigate the effects of high temperature (37 degrees C) and different humidity (50%, 70%, and 90%) on the leaf Bt protein expression of Bt cotton. At high temperature, temperature and humidity had no significant effects on the leaf Bt protein expression of the cultivars at peak squaring stage. At peak flowering stage, as compared with the control (25-30 degrees C and 60%-70% humidity), 37 degrees C and 50% humidity decreased the leaf Bt protein content of conventional cultivars significantly by 2.6%-3.0%. At peak bolling stage, compared with the control, 37 degrees C and 50% humidity decreased the leaf Bt protein content of DP410B, Sikang No. 1, and Sikang No. 3 significantly by 3.3%-5.8%. Among the four cultivars, DP410B and Daiza No. 1 had the highest leaf Bt protein content, while Sikang No. 1 had the lowest one.

  17. 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....

  18. 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....

  19. 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...

  20. 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...

  1. 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....

  2. 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...

  3. 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....

  4. 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....

  5. 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...

  6. Historical Air Temperatures Across the Hawaiian Islands

    NASA Astrophysics Data System (ADS)

    Kagawa-Viviani, A.; Giambelluca, T. W.

    2015-12-01

    This study focuses on an analysis of daily temperature from over 290 ground-based stations across the Hawaiian Islands from 1905-2015. Data from multiple stations were used to model environmental lapse rates by fitting linear regressions of mean daily Tmax and Tmin on altitude; piecewise regressions were also used to model the discontinuity introduced by the trade wind inversion near 2150m. Resulting time series of both model coefficients and lapse rates indicate increasing air temperatures near sea level (Tmax: 0.09°C·decade-1 and Tmin: 0.23°C·decade-1 over the most recent 65 years). Evaluation of lapse rates during this period suggest Tmax lapse rates (~0.6°C·100m-1) are decreasing by 0.006°C·100m-1decade-1 due to rapid high elevation warming while Tmin lapse rates (~0.8°C·100m-1) are increasing by 0.002°C·100m-1decade-1 due to the stronger increase in Tmin at sea level versus at high elevation. Over the 110 year period, temperatures tend to vary coherently with the PDO index. Our analysis verifies warming trends and temperature variability identified earlier by analysis of selected index stations. This method also provides temperature time series we propose are more robust to station inhomogeneities.

  7. AN EVALUATION OF THREE EMPIRICAL AIR-TO-LEAF MODELS FOR POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS

    EPA Science Inventory

    Three empirical air-to-leaf models for estimating grass concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (abbreviated dioxins and furans) from air concentrations of these compounds are described and tested against two field data sets. All are empirical in th...

  8. Convergence in the temperature response of leaf respiration across biomes and plant functional types

    PubMed Central

    Heskel, Mary A.; O’Sullivan, Odhran S.; Reich, Peter B.; Tjoelker, Mark G.; Weerasinghe, Lasantha K.; Penillard, Aurore; Egerton, John J. G.; Creek, Danielle; Bloomfield, Keith J.; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R.; Martinez-de la Torre, Alberto; Griffin, Kevin L.; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H.; Atkin, Owen K.

    2016-01-01

    Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration–temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates. PMID:27001849

  9. Convergence in the temperature response of leaf respiration across biomes and plant functional types.

    PubMed

    Heskel, Mary A; O'Sullivan, Odhran S; Reich, Peter B; Tjoelker, Mark G; Weerasinghe, Lasantha K; Penillard, Aurore; Egerton, John J G; Creek, Danielle; Bloomfield, Keith J; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R; Martinez-de la Torre, Alberto; Griffin, Kevin L; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H; Atkin, Owen K

    2016-04-05

    Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration-temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates.

  10. Thermal Coupling Between Air and Ground Temperatures in the CMIP5 Historical and Future Simulations

    NASA Astrophysics Data System (ADS)

    García-García, A.; Cuesta-Valero, F. J.; Smerdon, J. E.; Beltrami, H.

    2015-12-01

    The thermal coupling between air and ground temperatures is investigated herein for General Circulation Models (GCMs) that participated in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). For each simulation, we evaluate the regional relationship between air and ground temperatures to study surface energy fluxes and the attenuation of the annual temperature signal across the air-ground interface and into the shallow subsurface for North America. Our results show that the transport of energy across the air-ground interface and into the shallow subsurface is different across GCMs and is dependent on the land surface models that each employs. The variability of the difference between air and ground temperatures is high among simulations and is not dependent on the depth of the bottom boundary of the subsurface soil model. The difference between air and ground temperatures differs significantly from observations. Additionally, while the variability among GCMs can be explained by the physics of the land surface models, the regional variability of the air-ground coupling is associated with the model treatment of soil properties as well as snow and vegetation processes within GCMs. The difference between air and ground temperatures at high latitudes within the majority of the CMIP5 models is directly proportional to the amount of snow on the ground, due to the insulating effect of snow cover. On the other hand, the difference between air and ground temperatures at low latitudes within some of the CMIP5 models is inversely proportional to the vegetation cover (leaf area index), due to changes in latent and sensible heat fluxes. The large variability among GCMs and the marked dependency of the results on the choice of the land-surface model illustrates the need for improving the simulation of air-ground coupling in land-surface models towards a robust simulation of near-surface processes, such as permafrost and soil carbon stability within GCMs.

  11. [Effects of air temperature and soil moisture on flavonoids accumulation in Ginkgo biloba leaves].

    PubMed

    Wang, Gui-Bin; Guo, Xu-Qin; Chang, Li; Cao, Fu-Liang

    2013-11-01

    Taking the 2-year old Ginkgo biloba seedlings as test materials, a pot experiment was conducted in an artificial climate chamber to study the effects of air temperature and soil moisture on the flavonoids accumulation in leaves. Three levels of air temperature (15/5 degrees C, 25/15 degrees C, and 35/25 degrees C day/night) and three levels of soil moisture (55%-60%, 40%-45%, and 30%-35% of field capacity) were installed, yielding nine temperature-soil moisture combinations. Under the three levels of soil moisture, the quercetin, kaempferol, isorhamnetin, and total flavonoids contents in the leaves were higher at 15/5 degrees C than at 25/15 degrees C and 35/25 degrees C. Soil moisture had minor effects on the flavonoids accumulation. The leaf kaempferol content was the highest, followed by quercetin and isorhamnetin. The total flavonoids yield per plant at 35/25 degrees C was higher than that at 15/5 degrees C and 25/15 degrees C. It was suggested that to adopt appropriate soil covering and watering before harvesting to decrease the ambient temperature could benefit the enhancement of leaf flavonoids content and the improvement of per unit area flavonoids production in G. biloba leaf-harvesting plantation.

  12. Photosynthesis of young apple trees in response to low sink demand under different air temperatures.

    PubMed

    Fan, Pei G; Li, Lian S; Duan, Wei; Li, Wei D; Li, Shao H

    2010-03-01

    Gas exchange, chlorophyll fluorescence, photosynthetic end products and related enzymes in source leaves in response to low sink demand after girdling to remove the root sink were assessed in young apple trees (Malus pumila) grown in two greenhouses with different air temperatures for 5 days. Compared with the non-girdled control in the low-temperature greenhouse (diurnal maximum air temperature <32 degrees C), low sink demand resulted in lower net photosynthetic rate (P(n)), stomatal conductance (g(s)) and transpiration rate (E) but higher leaf temperature on Day 5, while in the high-temperature greenhouse (diurnal maximum air temperature >36 degrees C), P(n), g(s) and E declined from Day 3 onwards. Moreover, gas exchange responded more to low sink demand in the high-temperature greenhouse than in the low-temperature greenhouse. Decreased P(n) at low sink demand was accompanied by lower intercellular CO(2) concentrations in the low-temperature greenhouse. However, decreased maximal photochemical efficiency, potential activity, efficiency of excitation capture, actual efficiency and photochemical quenching, with increased minimal fluorescence and non-photochemical quenching of photosystem II (PSII), were observed in low sink demand leaves only in the high-temperature greenhouse. In addition, low sink demand increased leaf starch and soluble carbohydrate content in both greenhouses but did not result in lower activity of enzymes involved in metabolism. Thus, decreased P(n) under low sink demand was independent of a direct effect of end-product feedback but rather depended on a high temperature threshold. The lower P(n) was likely due to stomatal limitation in the low-temperature greenhouse, but mainly due to non-stomatal limitation in the high-temperature greenhouse.

  13. Thermal Coupling between Air and Ground Temperatures in the CMIP5 Historical and Future Simulations

    NASA Astrophysics Data System (ADS)

    García-García, Almudena; José Cuesta-Valero, Francisco; Beltrami, Hugo; Smerdon, Jason

    2016-04-01

    The decadal-scale thermal coupling between air and ground temperatures across North America is examined for 32 General Circulation Models (GCMs) from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). For each simulation, we evaluate the relationship between air and ground temperatures. Our results show that the transport of energy across the air-ground interface differs from observations, and among GCMs depending on each model's land-surface component. While the decadal variability among GCMs can be explained by the physics and parameterizations of each land-surface model, the spatial variability of the air-ground coupling for the historical and future simulations is associated with model treatment of the soil thermal properties as well as with processes associated with snow and vegetation cover within GCMs. The difference between air and ground temperatures at high latitudes within the majority of the CMIP5 models is related to the insulating effect of snow cover. On the other hand, the difference between air and ground temperatures at low latitudes within some of the CMIP5 models is inversely proportional to the leaf area index, due to changes in latent and sensible heat fluxes. The large variability among GCMs and the marked dependency of the results on the choice of the land-surface model illustrates the need for improving the simulation of air-ground coupling in land-surface models towards a robust simulation of near-surface processes, such as permafrost and soil carbon stability within GCMs.

  14. Variation in the urban vegetation, surface temperature, air temperature nexus.

    PubMed

    Shiflett, Sheri A; Liang, Liyin L; Crum, Steven M; Feyisa, Gudina L; Wang, Jun; Jenerette, G Darrel

    2017-02-01

    Our study examines the urban vegetation - air temperature (Ta) - land surface temperature (LST) nexus at micro- and regional-scales to better understand urban climate dynamics and the uncertainty in using satellite-based LST for characterizing Ta. While vegetated cooling has been repeatedly linked to reductions in urban LST, the effects of vegetation on Ta, the quantity often used to characterize urban heat islands and global warming, and on the interactions between LST and Ta are less well characterized. To address this need we quantified summer temporal and spatial variation in Ta through a network of 300 air temperature sensors in three sub-regions of greater Los Angeles, CA, which spans a coastal to desert climate gradient. Additional sensors were placed within the inland sub-region at two heights (0.1m and 2m) within three groundcover types: bare soil, irrigated grass, and underneath citrus canopy. For the entire study region, we acquired new imagery data, which allowed calculation of the normalized difference vegetation index (NDVI) and LST. At the microscale, daytime Ta measured along a vertical gradient, ranged from 6 to 3°C cooler at 0.1 and 2m, underneath tall canopy compared to bare ground respectively. At the regional scale NDVI and LST were negatively correlated (p<0.001). Relationships between diel variation in Ta and daytime LST at the regional scale were progressively weaker moving away from the coast and were generally limited to evening and nighttime hours. Relationships between NDVI and Ta were stronger during nighttime hours, yet effectiveness of mid-day vegetated cooling increased substantially at the most arid region. The effectiveness of vegetated Ta cooling increased during heat waves throughout the region. Our findings suggest an important but complex role of vegetation on LST and Ta and that vegetation may provide a negative feedback to urban climate warming.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  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, 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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…

  8. 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....

  9. 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....

  10. 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....

  11. 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....

  12. Global patterns of plant leaf N and P in relation to temperature and latitude.

    PubMed

    Reich, Peter B; Oleksyn, Jacek

    2004-07-27

    A global data set including 5,087 observations of leaf nitrogen (N) and phosphorus (P) for 1,280 plant species at 452 sites and of associated mean climate indices demonstrates broad biogeographic patterns. In general, leaf N and P decline and the N/P ratio increases toward the equator as average temperature and growing season length increase. These patterns are similar for five dominant plant groups, coniferous trees and four angiosperm groups (grasses, herbs, shrubs, and trees). These results support the hypotheses that (i) leaf N and P increase from the tropics to the cooler and drier midlatitudes because of temperature-related plant physiological stoichiometry and biogeographical gradients in soil substrate age and then plateau or decrease at high latitudes because of cold temperature effects on biogeochemistry and (ii) the N/P ratio increases with mean temperature and toward the equator, because P is a major limiting nutrient in older tropical soils and N is the major limiting nutrient in younger temperate and high-latitude soils.

  13. Global patterns of plant leaf N and P in relation to temperature and latitude

    PubMed Central

    Reich, Peter B.; Oleksyn, Jacek

    2004-01-01

    A global data set including 5,087 observations of leaf nitrogen (N) and phosphorus (P) for 1,280 plant species at 452 sites and of associated mean climate indices demonstrates broad biogeographic patterns. In general, leaf N and P decline and the N/P ratio increases toward the equator as average temperature and growing season length increase. These patterns are similar for five dominant plant groups, coniferous trees and four angiosperm groups (grasses, herbs, shrubs, and trees). These results support the hypotheses that (i) leaf N and P increase from the tropics to the cooler and drier midlatitudes because of temperature-related plant physiological stoichiometry and biogeographical gradients in soil substrate age and then plateau or decrease at high latitudes because of cold temperature effects on biogeochemistry and (ii) the N/P ratio increases with mean temperature and toward the equator, because P is a major limiting nutrient in older tropical soils and N is the major limiting nutrient in younger temperate and high-latitude soils. PMID:15213326

  14. Antioxidant activity and free radical-scavenging capacity of Gynura divaricata leaf extracts at different temperatures

    PubMed Central

    Wan, Chunpeng; Yu, Yanying; Zhou, Shouran; Liu, Wei; Tian, Shuge; Cao, Shuwen

    2011-01-01

    Background: Extraction temperature influences the total phenolic content (TPC), total flavonoid content (TFC) of medicinal plant extracts to a great extend. TPC and TFC are the principle activity constituents present in the plant. The effects of extraction temperature on TPC, TFC and free radical-scavenging capacity of Gynura divaricata leaf extracts are worth to study. Materials and Methods: Folin–Ciocalteu and aluminum chloride colorimetric assay were used to determine the TPC and TFC of Gynura divaricata leaf extracts at different temperatures. The antioxidant and free radical-scavenging activity were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and phosphomolybdenum methods. Results: TPC and TFC were significantly elevated with increasing extraction temperature (from 40°C to 100°C). However, TPC and TFC were not significantly different (P > 0.05) at the extraction temperatures 90°C and 100°C. Also, the extracts obtained at a higher temperature exhibited a significant free radical-scavenging activity compared with extraction at lower temperatures (P < 0.05). The TPCs (13.95-36.68 mg gallic acid equivalent/g dry material) were highly correlated with DPPH (R2 = 0.9229), ABTS (R2 = 0.9951) free radical-scavenging capacity, and total antioxidant activity (R2 = 0.9872) evaluated by phosphomolybdenum method. Conclusion: The TPC and TFC of G. divaricata leaf was significantly influenced by the extraction temperatures, which were the main antioxidant constituents present in the G. divaricata plant. PMID:21472078

  15. Kaolin-based foliar reflectant and water deficit influence Malbec leaf and berry temperature, pigments, and photosynthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of a kaolin-based foliar reflectant on traits of commercial interest in the red-skinned wine grape cultivar Malbec (Vitis vinifera L.) were evaluated over three growing seasons by measuring the surface temperatures of leaves and clusters, leaf-level assimilation, leaf and berry pigment c...

  16. Does elevated CO2 protect photosynthesis from damage by high temperature via modifying leaf water status in maize seedlings?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because high temperatures under field conditions are associated with high water vapor pressure deficits, often causing leaf desiccation, we hypothesized that decreased stomatal conductance at elevated carbon dioxide may increase leaf water potential and protect photosynthesis in C4 species from dama...

  17. Ontogenic changes rather than difference in temperature cause understory trees to leaf out earlier.

    PubMed

    Vitasse, Yann

    2013-04-01

    In a temperate climate, understory trees leaf out earlier than canopy trees, but the cause of this discrepancy remains unclear. This study aims to investigate whether this discrepancy results from ontogenic changes or from microclimatic differences. Seedlings of five deciduous tree species were grown in spring 2012 in the understory and at canopy height using a 45-m-high construction crane built into a mature mixed forest in the foothills of the Swiss Jura Mountains. The leaf development of these seedlings, as well as conspecific adults, was compared, taking into account the corresponding microclimate. The date of leaf unfolding occurred 10-40 d earlier in seedlings grown at canopy level than in conspecific adults. Seedlings grown in the understory flushed c. 6 d later than those grown at canopy height, which can be attributed to the warmer temperatures recorded at canopy height (c. 1°C warmer). This study demonstrates that later leaf emergence of canopy trees compared with understory trees results from ontogenic changes and not from the vertical thermal profile that exists within forests. This study warns against the assumption that phenological data obtained in warming and photoperiod experiments on juvenile trees can be used for the prediction of forest response to climate warming.

  18. Isolation and identification of plant phenolic compounds in birch leaves: Air pollution stress and leaf phenolics

    NASA Astrophysics Data System (ADS)

    Loponen, Jyrki Mikael

    Chromatographic (analytical and preparative HPLC), chemical (hydrolysis) and spectroscopic (UV, 1H NMR, 13C NMR and MS) techniques proved to be suitable tools for the structure identification of plant phenolic compounds. More than 30 individual phenolic compounds were detected and quantified. Detailed information of the structures of individual compounds was determined after isolation from birch leaves. Ten flavonoid glycosides were identified. Two of them, myricetin-3-O-α-L-(acetyl)-rhamnopyranoside and quercetin-3-O-α-L-(4/prime'-O-acetyl)- rhamnopyranoside, have been rarely found in birch leaves. Further, some characterized major phenolics with non- flavonoid structures in our study were 1-O-galloyl- β-D-(2-O-acetyl)-glucopyranose, gallic, chlorogenic, neochlorogenic, cis- and trans-forms of 3- and 5-p-coumaroylquinic acids. The presence of gallotannin group was evidenced by strong positive correlations between concentrations of these gallotannins (preliminary identified by HPLC and UV spectra) and the protein precipitation capacity of extracts. Content of gallotannins decreased with leaf growth and maturation. It is known that concentrations of phenolic compounds regularly increase in slowly growing stressed plants and therefore, it is natural that they are also sensitive to different forms of air pollution. Total content and the contents of some individual phenolics correlated negatively with the distance from the pollution source in our study area. In addition to comparing absolute concentrations of compounds in question, the within-tree correlations or within-tree variations of the relevant compounds between polluted and control areas were an alternative approach. Differences in pairwise correlations between the investigated leaf phenolic compounds indicated the competition between some gallotannins and p-coumaroylquinic acids on the polluted but not on the control site. Air pollution seems to be a stress factor for birch trees associated with

  19. Light, temperature, and leaf nitrogen distribution in the tropical rain forest of Biosphere 2 and their importance in the mathematical models for global environmental changes

    NASA Technical Reports Server (NTRS)

    Tohda, Motofumi

    1997-01-01

    As the environmental changes occur throughout the world in rapid rate, we need to have further understandings for our planet. Since the ecosystems are so complex, it is almost impossible for us to integrate every factor. However, mathematical models are powerful tools which can be used to simulate those ecosystems with limited data. In this project, I collected light intensity, canopy leaf temperature and Air Handler (AHU) temperature, and nitrogen concentration in the leaves for different profiles in the rainforest mesocosm. These data will later be put into mathematical models such as "big-leaf" and "sun/shade" models to determine how these factors will affect CO2 exchange in the rainforest. As rainforests are diminishing from our planet and their existence is very important for all living things on earth, it is necessary for us to learn more about the unique system of rainforests and how we can co-exist rather than destroy.

  20. Honeybee flight metabolic rate: does it depend upon air temperature?

    PubMed

    Woods, William A; Heinrich, Bernd; Stevenson, Robert D

    2005-03-01

    Differing conclusions have been reached as to how or whether varying heat production has a thermoregulatory function in flying honeybees Apis mellifera. We investigated the effects of air temperature on flight metabolic rate, water loss, wingbeat frequency, body segment temperatures and behavior of honeybees flying in transparent containment outdoors. For periods of voluntary, uninterrupted, self-sustaining flight, metabolic rate was independent of air temperature between 19 and 37 degrees C. Thorax temperatures (T(th)) were very stable, with a slope of thorax temperature on air temperature of 0.18. Evaporative heat loss increased from 51 mW g(-1) at 25 degrees C to 158 mW g(-1) at 37 degrees C and appeared to account for head and abdomen temperature excess falling sharply over the same air temperature range. As air temperature increased from 19 to 37 degrees C, wingbeat frequency showed a slight but significant increase, and metabolic expenditure per wingbeat showed a corresponding slight but significant decrease. Bees spent an average of 52% of the measurement period in flight, with 19 of 78 bees sustaining uninterrupted voluntary flight for periods of >1 min. The fraction of time spent flying declined as air temperature increased. As the fraction of time spent flying decreased, the slope of metabolic rate on air temperature became more steeply negative, and was significant for bees flying less than 80% of the time. In a separate experiment, there was a significant inverse relationship of metabolic rate and air temperature for bees requiring frequent or constant agitation to remain airborne, but no dependence for bees that flew with little or no agitation; bees were less likely to require agitation during outdoor than indoor measurements. A recent hypothesis explaining differences between studies in the slope of flight metabolic rate on air temperature in terms of differences in metabolic capacity and thorax temperature is supported for honeybees in voluntary

  1. Low-temperature leaf photosynthesis of a Miscanthus germplasm collection correlates positively to shoot growth rate and specific leaf area

    PubMed Central

    Jiao, Xiurong; Kørup, Kirsten; Andersen, Mathias Neumann; Petersen, Karen Koefoed; Prade, Thomas; Jeżowski, Stanisław; Ornatowski, Szymon; Górynowicz, Barbara; Spitz, Idan; Lærke, Poul Erik; Jørgensen, Uffe

    2016-01-01

    Background and Aims The C4 perennial grass miscanthus has been found to be less sensitive to cold than most other C4 species, but still emerges later in spring than C3 species. Genotypic differences in miscanthus were investigated to identify genotypes with a high cold tolerance at low temperatures and quick recovery upon rising temperatures to enable them to exploit the early growing season in maritime cold climates. Suitable methods for field screening of cold tolerance in miscanthus were also identified. Methods Fourteen genotypes of M. sacchariflorus, M. sinensis, M. tinctorius and M. × giganteus were selected and grown under warm (24 °C) and cold (14 °C) conditions in a controlled environment. Dark-adapted chlorophyll fluorescence, specific leaf area (SLA) and net photosynthetic rate at a photosynthetically active radiation (PAR) of 1000 μmol m–2 s–1 (A1000) were measured. Photosynthetic light and CO2 response curves were obtained from 11 of the genotypes, and shoot growth rate was measured under field conditions. Key Results A positive linear relationship was found between SLA and light-saturated photosynthesis (Asat) across genotypes, and also between shoot growth rate under cool field conditions and A1000 at 14 °C in a climate chamber. When lowering the temperature from 24 to 14 °C, one M. sacchariflorus exhibited significantly higher Asat and maximum photosynthetic rate in the CO2 response curve (Vmax) than other genotypes at 14 °C, except M. × giganteus ‘Hornum’. Several genotypes returned to their pre-chilling A1000 values when the temperature was increased to 24 °C after 24 d growth at 14 °C. Conclusions One M. sacchariflorus genotype had similar or higher photosynthetic capacity than M. × giganteus, and may be used for cultivation together with M. × giganteus or for breeding new interspecies hybrids with improved traits for temperate climates. Two easily measured variables, SLA and shoot growth rate, may be useful for

  2. Leaf conductance decreased under free-air CO2 enrichment (FACE) for three perennials in the Nevada desert

    USGS Publications Warehouse

    Nowak, Robert S.; Defalco, Lesley A.; Wilcox, Carolyn S.; Jordan, Dean N.; Coleman, James S.; Seemann, Jeffrey R.; Smith, Stanley D.

    2001-01-01

    A common response of plants to elevated atmospheric CO2 concentration (CO2) is decreased leaf conductance. Consequently, leaf temperature is predicted to increase under elevated CO2.Diurnal patterns of leaf conductance and temperature were measured for three desert perennials, the C3 shrub Larrea tridentata, C3 tussock grass Achnatherum hymenoides and C4tussock grass Pleuraphis rigida, at the Nevada Desert FACE facility. Measurements were made on ambient and c. 550 µmol mol−1 CO2 plots through both a wet and dry year.Reductions in conductance were 35%, 20% and 13% for Pleuraphis, Achnatherum and Larrea, respectively. Decreased conductance occurred throughout the day only for Pleuraphis. Both C3species had smaller CO2 effects during dry periods than wet. Leaf temperature did not differ significantly between elevated and ambient CO2 for any species. Comparisons of blower-control and nonring plots indicated that the FACE apparatus did not confound our results.All three species exhibited decreased leaf conductance under elevated CO2, although reductions were not uniform during the day or among years. Nonetheless, leaf energy balance was only minimally changed for these microphyllous desert perennials.

  3. General patterns of acclimation of leaf respiration to elevated temperatures across biomes and plant types.

    PubMed

    Slot, Martijn; Kitajima, Kaoru

    2015-03-01

    Respiration is instrumental for survival and growth of plants, but increasing costs of maintenance processes with warming have the potential to change the balance between photosynthetic carbon uptake and respiratory carbon release from leaves. Climate warming may cause substantial increases of leaf respiratory carbon fluxes, which would further impact the carbon balance of terrestrial vegetation. However, downregulation of respiratory physiology via thermal acclimation may mitigate this impact. We have conducted a meta-analysis with data collected from 43 independent studies to assess quantitatively the thermal acclimation capacity of leaf dark respiration to warming of terrestrial plant species from across the globe. In total, 282 temperature contrasts were included in the meta-analysis, representing 103 species of forbs, graminoids, shrubs, trees and lianas native to arctic, boreal, temperate and tropical ecosystems. Acclimation to warming was found to decrease respiration at a set temperature in the majority of the observations, regardless of the biome of origin and growth form, but respiration was not completely homeostatic across temperatures in the majority of cases. Leaves that developed at a new temperature had a greater capacity for acclimation than those transferred to a new temperature. We conclude that leaf respiration of most terrestrial plants can acclimate to gradual warming, potentially reducing the magnitude of the positive feedback between climate and the carbon cycle in a warming world. More empirical data are, however, needed to improve our understanding of interspecific variation in thermal acclimation capacity, and to better predict patterns in respiratory carbon fluxes both within and across biomes in the face of ongoing global warming.

  4. 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).

  5. The effect of temperature and moisture on trace gas emissions from deciduous and coniferous leaf litter

    NASA Astrophysics Data System (ADS)

    Gritsch, Christine; Egger, Florian; Zehetner, Franz; Zechmeister-Boltenstern, Sophie

    2016-05-01

    The forest litter layer lies at the boundary between soil and atmosphere and is a major factor in biogeochemical cycles. While there are several studies on how the litter layer controls soil trace gas emissions, litter emissions itself are less well understood, and it is still unclear how important gases respond to changing temperature and moisture. In order to assess leaf litter gas exchange, we conducted laboratory incubation experiments in which the full set of climate relevant gases, i.e., carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and nitric oxide (NO) coming from deciduous and coniferous leaf litter were measured at five temperatures and seven moisture contents. In addition, we compared litter and soil from different origin in terms of temperature/moisture responses of gas fluxes and investigated possible interactions between the two climate factors. Deciduous litter emitted more CO2 (up to 335 mg CO2-C kg-1 h-1) than coniferous litter, whereas coniferous litter released maximum amounts of NO (207 µg NO-N kg-1 h-1). N2O was only emitted from litter under very moist and warm conditions (>70% wet weight, >10°C). CH4 emissions were close to zero. Temperature sensitivities of litter emissions were generally lower than for soil emissions. Nevertheless, wet and warm conditions always enhanced litter emissions, suggesting a strong feedback effect of the litter layer to predicted future climate change.

  6. Spatial and seasonal variability of temperature responses of biochemical photosynthesis parameters and leaf nitrogen content within a Pinus densiflora crown.

    PubMed

    Han, Qingmin; Kawasaki, Tatsuro; Nakano, Takashi; Chiba, Yukihiro

    2004-07-01

    We measured seasonal variation in area-based nitrogen concentration (N), maximum rate of carboxylation (Vcmax) and maximum rate of electron transport (Jmax) in 1-year-old needles along four first-order branches within a Pinus densiflora Sieb. & Zucc. crown, and analyzed their relationships to growth irradiance and temperature. Each leaf light environment was expressed as a ratio of the monthly mean of daily integrated photosynthetically active irradiance (Iint) for the particular needle to Iint above the canopy (Irel). Needle N decreased in the upper crown during the development of new needles, whereas it remained fairly constant in the lower crown, reflecting differences between upper and lower crown needles in their contribution to the nitrogen of new needles. Gradients of N within the crown were correlated with Irel in all seasons (r2 = 0.40-0.78). Seasonal variation in N was weakly correlated with mean daily air minimum temperatures. Both Vcmax and Jmax showed seasonal variation in all first-order branches, and decreased to their lowest values in winter. The gradients of Vcmax and Jmax within the crown were not correlated with Irel in some seasons, but were correlated with changes in N in most months (r2 = 0.33-0.75), except in the winter. Furthermore, the regression slope of the relationship between N and Vcmax and the temperature response of Vcmax and Jmax exhibited seasonal variation.

  7. Leaf optical properties reflect variation in photosynthetic metabolism and its sensitivity to temperature

    PubMed Central

    Serbin, Shawn P.; Dillaway, Dylan N.; Kruger, Eric L.; Townsend, Philip A.

    2012-01-01

    Researchers from a number of disciplines have long sought the ability to estimate the functional attributes of plant canopies, such as photosynthetic capacity, using remotely sensed data. To date, however, this goal has not been fully realized. In this study, fresh-leaf reflectance spectroscopy (λ=450–2500 nm) and a partial least-squares regression (PLSR) analysis were used to estimate key determinants of photosynthetic capacity—namely the maximum rates of RuBP carboxylation (Vcmax) and regeneration (Jmax)—measured with standard gas exchange techniques on leaves of trembling aspen and eastern cottonwood trees. The trees were grown across an array of glasshouse temperature regimes. The PLSR models yielded accurate and precise estimates of Vcmax and Jmax within and across species and glasshouse temperatures. These predictions were developed using unique contributions from different spectral regions. Most of the wavelengths selected were correlated with known absorption features related to leaf water content, nitrogen concentration, internal structure, and/or photosynthetic enzymes. In a field application of our PLSR models, spectral reflectance data effectively captured the short-term temperature sensitivities of Vcmax and Jmax in aspen foliage. These findings highlight a promising strategy for developing remote sensing methods to characterize dynamic, environmentally sensitive aspects of canopy photosynthetic metabolism at broad scales. PMID:21984647

  8. 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.

  9. Cellulose δ18O is an index of leaf-to-air vapor pressure difference (VPD) in tropical plants

    PubMed Central

    Kahmen, Ansgar; Sachse, Dirk; Arndt, Stefan K.; Tu, Kevin P.; Farrington, Heraldo; Vitousek, Peter M.; Dawson, Todd E.

    2011-01-01

    Cellulose in plants contains oxygen that derives in most cases from precipitation. Because the stable oxygen isotope composition, δ18O, of precipitation is associated with environmental conditions, cellulose δ18O should be as well. However, plant physiological models using δ18O suggest that cellulose δ18O is influenced by a complex mix of both climatic and physiological drivers. This influence complicates the interpretation of cellulose δ18O values in a paleo-context. Here, we combined empirical data analyses with mechanistic model simulations to i) quantify the impacts that the primary climatic drivers humidity (ea) and air temperature (Tair) have on cellulose δ18O values in different tropical ecosystems and ii) determine which environmental signal is dominating cellulose δ18O values. Our results revealed that ea and Tair equally influence cellulose δ18O values and that distinguishing which of these factors dominates the δ18O values of cellulose cannot be accomplished in the absence of additional environmental information. However, the individual impacts of ea and Tair on the δ18O values of cellulose can be integrated into a single index of plant-experienced atmospheric vapor demand: the leaf-to-air vapor pressure difference (VPD). We found a robust relationship between VPD and cellulose δ18O values in both empirical and modeled data in all ecosystems that we investigated. Our analysis revealed therefore that δ18O values in plant cellulose can be used as a proxy for VPD in tropical ecosystems. As VPD is an essential variable that determines the biogeochemical dynamics of ecosystems, our study has applications in ecological-, climate-, or forensic-sciences. PMID:21245322

  10. 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.

  11. 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.

  12. Monitored summer peak attic air temperatures in Florida residences

    SciTech Connect

    Parker, D.S.; Sherwin, J.R.

    1998-12-31

    The Florida Solar Energy Center (FSEC) has analyzed measured summer attic air temperature data taken for some 21 houses (three with two different roof configurations) over the last several years. The analysis is in support of the calculation within ASHRAE Special Project 152P, which will be used to estimate duct system conductance gains that are exposed to the attic space. Knowledge of prevailing attic thermal conditions are critical to the duct heat transfer calculations for estimation of impacts on residential cooling system sizing. The field data were from a variety of residential monitoring projects that were classified according to intrinsic differences in roofing configurations and characteristics. The sites were occupied homes spread around the state of Florida. There were a variety of different roofing construction types, roof colors, and ventilation configurations. Data at each site were obtained from June 1 to September 30 according to the ASHRAE definition of summer. The attic air temperature and ambient air temperature were used for the data analysis. The attic air temperature was measured with a shielded type-T thermocouple at mid-attic height, halfway between the decking and insulation surface. The ambient air temperature was obtained at each site by thermocouples located inside a shielded exterior enclosure at a 3 to 4 m (10--12 ft) height. The summer 15-minute data from each site were sorted by the average ambient air temperature into the top 2.5% of the observations of the highest temperature. Within this limited group of observations, the average outside air temperature, attic air temperature, and coincident difference were reported.

  13. Solar activity influence on air temperature regimes in caves

    NASA Astrophysics Data System (ADS)

    Stoeva, Penka; Mikhalev, Alexander; Stoev, Alexey

    Cave atmospheres are generally included in the processes that happen in the external atmosphere as circulation of the cave air is connected with the most general circulation of the air in the earth’s atmosphere. Such isolated volumes as the air of caves are also influenced by the variations of solar activity. We discuss cave air temperature response to climate and solar and geomagnetic activity for four show caves in Bulgaria studied for a period of 46 years (1968 - 2013). Everyday noon measurements in Ledenika, Saeva dupka, Snezhanka and Uhlovitsa cave have been used. Temperatures of the air in the zone of constant temperatures (ZCT) are compared with surface temperatures recorded at meteorological stations situated near about the caves - in the towns of Vratsa, Lovech, Peshtera and Smolyan, respectively. For comparison, The Hansen cave, Middle cave and Timpanogos cave from the Timpanogos Cave National Monument, Utah, USA situated nearly at the same latitude have also been examined. Our study shows that the correlation between cave air temperature time series and sunspot number is better than that between the cave air temperature and Apmax indices; that t°ZCT is rather connected with the first peak in geomagnetic activity, which is associated with transient solar activity (CMEs) than with the second one, which is higher and connected with the recurrent high speed streams from coronal holes. Air temperatures of all examined show caves, except the Ledenika cave, which is ice cave show decreasing trends. On the contrary, measurements at the meteorological stations show increasing trends in the surface air temperatures. The trend is decreasing for the Timpanogos cave system, USA. The conclusion is that surface temperature trends depend on the climatic zone, in which the cave is situated, and there is no apparent relation between temperatures inside and outside the caves. We consider possible mechanism of solar cosmic rays influence on the air temperatures in caves

  14. Water stress detection in potato plants using leaf temperature, emissivity, and reflectance

    NASA Astrophysics Data System (ADS)

    Gerhards, Max; Rock, Gilles; Schlerf, Martin; Udelhoven, Thomas

    2016-12-01

    Water stress is one of the most critical abiotic stressors limiting crop development. The main imaging and non-imaging remote sensing based techniques for the detection of plant stress (water stress and other types of stress) are thermography, visible (VIS), near- and shortwave infrared (NIR/SWIR) reflectance, and fluorescence. Just very recently, in addition to broadband thermography, narrowband (hyperspectral) thermal imaging has become available, which even facilitates the retrieval of spectral emissivity as an additional measure of plant stress. It is, however, still unclear at what stage plant stress is detectable with the various techniques. During summer 2014 a water treatment experiment was run on 60 potato plants (Solanum tuberosum L. Cilena) with one half of the plants watered and the other half stressed. Crop response was measured using broadband and hyperspectral thermal cameras and a VNIR/SWIR spectrometer. Stomatal conductance was measured using a leaf porometer. Various measures and indices were computed and analysed for their sensitivity towards water stress (Crop Water Stress Index (CWSI), Moisture Stress Index (MSI), Photochemical Reflectance Index (PRI), and spectral emissivity, amongst others). The results show that water stress as measured through stomatal conductance started on day 2 after watering was stopped. The fastest reacting, i.e., starting on day 7, indices were temperature based measures (e.g., CWSI) and NIR/SWIR reflectance based indices related to plant water content (e.g., MSI). Spectral emissivity reacted equally fast. Contrarily, visual indices (e.g., PRI) either did not respond at all or responded in an inconsistent manner. This experiment shows that pre-visual water stress detection is feasible using indices depicting leaf temperature, leaf water content and spectral emissivity.

  15. 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...

  16. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... must be made within 100 cm of the air-intake of the engine. The measurement location must be either in... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test...

  17. 40 CFR 91.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... must be made within 100 cm of the air-intake of the engine. The measurement location must be either in... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test...

  18. 40 CFR 90.309 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... location must be within 10 cm of the engine intake system (i.e., the air cleaner, for most engines.) (b... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19...

  19. The apparent temperature response of leaf respiration depends on the timescale of measurements: a study of two cold climate species.

    PubMed

    Bruhn, D; Schortemeyer, M; Edwards, E J; Egerton, J J G; Hocart, C H; Evans, J R; Ball, M C

    2008-03-01

    Productivity and climate models often use a constant Q10 for plant respiration, assuming tight control of respiration by temperature. We studied the temperature response of leaf respiration of two cold climate species (the Australian tree Eucalyptus pauciflora and the subantarctic megaherb Pringlea antiscorbutica, both measured in a field setting) on a short timescale (minutes) during different times within a diel course, and on a longer timescale, using diel variations in ambient temperature. There were great variations in Q10 depending on measuring day, measuring time and measuring method. When Q10 was calculated from short-term (15 min) manipulations of leaf temperature, the resulting values were usually markedly smaller than when Q10 was calculated from measurements at ambient leaf temperatures spread over a day. While for E. pauciflora, Q10 estimates decreased with rising temperature (corroborating the concept of a temperature-dependent Q10), the opposite was the case for P. antiscorbutica. Clearly, factors other than temperature co-regulate both leaf respiration rates and temperature sensitivity and contribute to diel and seasonal variation of respiration.

  20. Physiological and Anatomical Response of Plant Leaf Tissue to Designated Air Pollutants.

    DTIC Science & Technology

    1982-01-07

    paren- chyma near stomata , and peroxyacetyl nitrate results in bronzing of the abaxial leaf surface (Middleton, 1961; Rich, 1964; Darley and Middleton...Does the frequency of adaxial stomata correlate with leaf sensitivity? Using drops of acid applied to leaves and usual microscopic techniques, we...assessed whether greater damage occurs on leaves which contain more frequent stomata on the upper leaf surface. j. Do HCl fumigated leaves exhibit a wound

  1. Effects of stoichiometry and temperature perturbations on beech leaf litter decomposition, enzyme activities and protein expression

    NASA Astrophysics Data System (ADS)

    Keiblinger, K. M.; Schneider, T.; Roschitzki, B.; Schmid, E.; Eberl, L.; Hämmerle, I.; Leitner, S.; Richter, A.; Wanek, W.; Riedel, K.; Zechmeister-Boltenstern, S.

    2012-11-01

    Microbes are major players in leaf litter decomposition and therefore advances in the understanding of their control on element cycling are of paramount importance. Our aim was to investigate the influence of leaf litter stoichiometry in terms of carbon (C) : nitrogen (N) : phosphorus (P) ratios on the decomposition processes and to track changes in microbial community structures and functions in response to temperature stress treatments. To elucidate how the stoichiometry of beech leaf litter (Fagus sylvatica L.) and stress treatments interactively affect the microbial decomposition processes, a terrestrial microcosm experiment was conducted. Beech litter from different Austrian sites covering C:N ratios from 39 to 61 and C:P ratios from 666 to 1729 were incubated at 15 °C and 60% moisture for six months. Part of the microcosms were then subjected to severe changes in temperature (+30 °C and -15 °C) to monitor the influence of temperature stress. Extracellular enzyme activities were assayed and respiratory activities measured. A semi-quantitative metaproteomics approach (1D-SDS PAGE combined with liquid chromatography and tandem mass spectrometry; unique spectral counting) was employed to investigate the impact of the applied stress treatments in dependency of litter stoichiometry on structure and function of the decomposing community. In litter with narrow C:nutrient (C:N, C:P) ratios, microbial decomposers were most abundant. Cellulase, chitinase, phosphatase and protease activity decreased after heat and freezing treatments. Decomposer communities and specific functions varied with site, i.e. stoichiometry. The applied stress combined with the respective time of sampling evoked changes of enzyme activities and litter pH. Freezing treatments resulted in a decline in residual plant litter material and increased fungal abundance, indicating slightly accelerated decomposition. Overall, a strong effect of litter stoichiometry on microbial community structures and

  2. 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

  3. Height-related trends in stomatal sensitivity to leaf-to-air vapour pressure deficit in a tall conifer.

    PubMed

    Woodruff, D R; Meinzer, F C; McCulloh, K A

    2010-01-01

    Stomatal responses to leaf-to-air vapour pressure deficit (LVPD), leaf water potential components, and cuticular properties were characterized for Douglas-fir (Pseudotsuga menziesii) foliage collected from tree tops along a height gradient from 5 m to 58 m in order to explore height-related trends in stomatal sensitivity to LVPD and to investigate the role of bulk leaf turgor and leaf cuticle thickness in determining stomatal behaviour. There were three distinct phases in the response of stomatal conductance (g(s)) to changes in LVPD. At low LVPD, g(s) increased with increasing LVPD (phase one). During the second phase, g(s) was maximal at low to intermediate LVPD and during the third phase g(s) declined steadily as LVPD increased. The responsiveness of g(s) to LVPD exhibited a height-related pattern such that maximum g(s) (g(s-max)) occurred at progressively greater LVPD with increasing height (r2=0.55, P=0.006). Bulk leaf osmotic potential at full turgor decreased with height (r2=0.77, P=0.00016), and LVPD at g(s-max) and at maximum crown conductance (g(c-max)) in the field were significantly correlated with leaf turgor (r2=0.92, P=0.0093). Cuticle thickness increased by 0.044 microm for every metre increase in height (r2=0.78, P=0.00015). The observed trends in the response of g(s) to LVPD along a height gradient, and their consistency with height-related trends in foliar osmotic potential suggest that osmotic adjustment at the tops of tall trees influences the relationship between g(s) and LVPD.

  4. Impact of high temperature on ethanol fermentation by Kluyveromyces marxianus immobilized on banana leaf sheath pieces.

    PubMed

    Le, Hoang Du; Thanonkeo, Pornthap; Le, Van Viet Man

    2013-10-01

    Ethanol fermentation was carried out with Kluyveromyces marxianus cells at various temperatures (30, 35, 40, and 45 °C). Fermentation performance of the immobilized yeast on banana leaf sheath pieces and the free yeast were evaluated and compared. Generally, ethanol production of the immobilized and free yeast was stable in a temperature range of 30-40 °C. Temperature of 45 °C restricted yeast growth and lengthened the fermentation. The immobilized yeast demonstrated faster sugar assimilation and higher ethanol level in the fermentation broth in comparison with the free yeast at all fermentation temperatures. Change in fatty acid level in cellular membrane was determined to clarify the response of the free and immobilized yeast to thermal stress. The free cells of K. marxianus responded to temperature increase by increasing saturated fatty acid (C16:0 and C18:0) level and by decreasing unsaturated fatty acid (C18:1 and C18:2) level in cellular membrane. For fermentation at 40 °C with immobilized cells of K. marxianus, however, the changes were not observed in both saturated fatty acid (C16:0) and unsaturated fatty acid (C18:1 and C18:2) level.

  5. 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].

  6. Ambient air temperature effects on the temperature of sewage sludge composting process.

    PubMed

    Huang, Qi-fei; Chen, Tong-bin; Gao, Ding; Huang, Ze-chun

    2005-01-01

    Using data obtained with a full-scale sewage sludge composting facility, this paper studied the effects of ambient air temperature on the composting temperature with varying volume ratios of sewage sludge and recycled compost to bulking agent. Two volume ratios were examined experimentally, 1: 0: 1 and 3: 1: 2. The results show that composting temperature was influenced by ambient air temperature and the influence was more significant when composting was in the temperature rising process: composting temperature changed 2.4-6.5 degrees C when ambient air temperature changed 13 degrees C. On the other hand, the influence was not significant when composting was in the high-temperature and/or temperature falling process: composting temperature changed 0.75-1.3 degrees C when ambient air temperature changed 8-15 degrees C. Hysteresis effect was observed in composting temperature's responses to ambient air temperature. When the ventilation capability of pile was excellent (at a volume ratio of 1:0:1), the hysteresis time was short and ranging 1.1-1.2 h. On the contrary, when the proportion of added bulking agent was low, therefore less porosity in the substrate (at a volume ratio of 3:1:2), the hysteresis time was long and ranging 1.9-3.1 h.

  7. Losses of leaf area owing to herbivory and early senescence in three tree species along a winter temperature gradient

    NASA Astrophysics Data System (ADS)

    González-Zurdo, P.; Escudero, A.; Nuñez, R.; Mediavilla, S.

    2016-11-01

    In temperate climates, evergreen leaves have to survive throughout low temperature winter periods. Freezing and chilling injuries can lead to accelerated senescence of part of the leaf surface, which contributes to a reduction of the lifespan of the photosynthetic machinery and of leaf lifetime carbon gain. Low temperatures are also associated with changes in foliar chemistry and morphology that affect consumption by herbivores. Therefore, the severity of foliar area losses caused by accelerated senescence and herbivory can change along winter temperature gradients. The aim of this study is to analyse such responses in the leaves of three evergreen species ( Quercus ilex, Q. suber and Pinus pinaster) along a climatic gradient. The leaves of all three species presented increased leaf mass per area (LMA) and higher concentrations of structural carbohydrates in cooler areas. Only the two oak species showed visible symptoms of damage caused by herbivory, this being less intense at the coldest sites. The leaves of all three species presented chlorotic and necrotic spots that increased in size with leaf age. The foliar surface affected by chlorosis and necrosis was larger at the sites with the coldest winters. Therefore, the effects of the winter cold on the lifespan of the photosynthetic machinery were contradictory: losses of leaf area due to accelerated senescence increased, but there was a decrease in losses caused by herbivory. The final consequences for carbon assimilation strongly depend on the exact timing of the appearance of the damage resulting from low temperature and grazing by herbivores.

  8. 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.

  9. Response of leaf litter decomposition to rises in atmospheric CO2 and temperature

    NASA Astrophysics Data System (ADS)

    Hammrich, A.; Flury, S.; Gessner, M. O.

    2007-05-01

    Atmospheric concentrations of CO2 have considerably increased in the last century and are expected to rise further. Elevated CO2 concentrations not only increase global temperature but also have potential to change plant litter quality, for example by increasing lignin content, changing C:N ratios and altering tannin contents. These chemical changes may interact with increased temperature to alter litter decomposition. To test whether changes in litter quality and warming affect decomposition, we conducted a field experiment with leaf litter collected from six species of mature deciduous trees exposed to either ambient or elevated CO2 levels. We used a set of 16 enclosures installed in four blocks in a freshwater marsh in a prealpine lake to test for the effects of CO2-mediated litter quality and temperature and the interaction of both factors. We measured leaf mass loss of the twelve litter types in control and heated enclosures (4 °C above ambient) and also in the open marsh. In contrast to expectations, species decomposing at low (oak and beech) and medium (hornbeam and maple) rates showed faster mass loss when leaves were grown under elevated CO2 conditions, whereas fast-decomposing species (cherry and basswood) showed no clear response. The accelerated decomposition of CO2-enriched litter could be due to higher amounts of nonstructural carbohydrates, which may have been either leached or readily degraded. Warming had a surprisingly small influence on mass loss of the tested litter species, and interactive effects were weak. These results suggest that direct and indirect effects of elevated CO2 levels on litter decomposition may not be readily predictable from first principles.

  10. Evaluating Changes in Paleo-temperature Gradients using Hydrogen Isotopic Compositions of Leaf-wax Biomarkers

    NASA Astrophysics Data System (ADS)

    Krishnan, S.; Huber, M.; Pagani, M.

    2014-12-01

    A long-standing problem in the paleoclimate modeling community has been the inability of the models to reproduce the shallow meridional temperature gradient (∆T) observed in proxy temperature records for the warm, greenhouse time intervals in Earth's history, such as the early Eocene. It is often stated that this mismatch indicates a missing high-latitude feedback mechanism in the climate models that would cause substantial polar amplification of warming. However, this issue is complicated by the potential biasing of proxy records due to issues related to temperature calibrations and/or diagenesis. In this study, we propose an alternative approach to estimate ∆T for these time intervals using hydrogen isotopic composition of leaf-wax biomarkers (dDleaf-wax) preserved in the sedimentary record. Today, dDleaf-wax is closely related to the hydrological cycle and source vegetation. In the mid- and high-latitudes, dDleaf-wax changes pertaining to the hydrological cycle can be interpreted using a Rayleigh distillation process, where evaporated moisture from the sub-tropics undergoes isotopic fractionation and becomes increasingly D-depleted during poleward transport. We develop a box model based on the Rayleigh distillation process that uses the global mean temperature for the time-period and geological archives of dDleaf-wax to estimate the meridional temperature gradient. We use this box model for the Paleocene-Eocene Thermal Maximum (PETM; ~56Ma), a rapid-warming event in the early Eocene where global warming is accompanied by evidence for increased input of greenhouse gases. We compile existing leaf-wax dDleaf-wax records from the extra-tropics to estimate ∆T before and during the PETM. Preliminary results suggest that the temperature gradient increased during the body of the PETM, contradicting our expectations based on temperature proxies. We also use this approach to estimate ∆T during other intervals in earth's history, such as the early Eocene. Further

  11. Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers.

    PubMed

    Follstad Shah, Jennifer J; Kominoski, John S; Ardón, Marcelo; Dodds, Walter K; Gessner, Mark O; Griffiths, Natalie A; Hawkins, Charles P; Johnson, Sherri L; Lecerf, Antoine; LeRoy, Carri J; Manning, David W P; Rosemond, Amy D; Sinsabaugh, Robert L; Swan, Christopher M; Webster, Jackson R; Zeglin, Lydia H

    2016-12-31

    Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community responses to temperature, factors that can influence the apparent temperature sensitivity of breakdown and the relative proportion of C lost to the atmosphere vs. stored or transported downstream. Here, we synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity, as measured by the activation energy (Ea , in eV). Temperature sensitivity of litter breakdown varied among twelve plant genera for which Ea could be calculated. Higher values of Ea were correlated with lower-quality litter, but these correlations were influenced by a single, N-fixing genus (Alnus). Ea values converged when genera were classified into three breakdown rate categories, potentially due to continual water availability in streams and rivers modulating the influence of leaf chemistry on breakdown. Across all data representing 85 plant genera, the Ea was 0.34 ± 0.04 eV, or approximately half the value (0.65 eV) predicted by metabolic theory. Our results indicate that average breakdown rates may increase by 5-21% with a 1-4 °C rise in water temperature, rather than a 10-45% increase expected, according to metabolic theory. Differential warming of tropical and temperate biomes could result in a similar proportional increase in breakdown rates, despite variation in Ea values for these regions (0.75 ± 0.13 eV and 0.27 ± 0.05 eV, respectively). The relative proportions of gaseous C loss and organic matter transport downstream should not change with rising temperature given that Ea values for breakdown mediated by microbes alone and microbes plus detritivores were similar at the global

  12. 40 CFR 89.325 - Engine intake air temperature measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... temperature measurement must be made within 122 cm of the engine. The measurement location must be made either... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES...

  13. Pulvinus activity, leaf movement and leaf water-use efficiency of bush bean ( Phaseplus vulgaris L.) in a hot environment

    NASA Astrophysics Data System (ADS)

    Raeini-Sarjaz, Mahmoud; Chalavi, Vida

    2008-11-01

    Pulvinus activity of Phaseolus species in response to environmental stimuli plays an essential role in heliotropic leaf movement. The aims of this study were to monitor the continuous daily pulvinus movement and pulvinus temperature, and to evaluate the effects of leaf movements, on a hot day, on instantaneous leaf water-use efficiency (WUEi), leaf gas exchange, and leaf temperature. Potted plants of Phaseolus vulgaris L. var. Provider were grown in Chicot sandy loam soil under well-watered conditions in a greenhouse. When the second trifoliate leaf was completely extended, one plant was selected to measure pulvinus movement using a beta-ray gauging (BRG) meter with a point source of thallium-204 (204Tl). Leaf gas exchange measurements took place on similar leaflets of three plants at an air temperature interval of 33-42°C by a steady-state LI-6200 photosynthesis system. A copper-constantan thermocouple was used to monitor pulvinus temperature. Pulvinus bending followed the daily diurnal rhythm. Significant correlations were found between the leaf-incident angle and the stomatal conductance ( R 2 = 0.54; P < 0.01), and photosynthesis rate ( R 2 = 0.84; P < 0.01). With a reduction in leaf-incidence angle and increase in air temperature, WUEi was reduced. During the measurements, leaf temperature remained below air temperature and was a significant function of air temperature ( r = 0.92; P < 0.01). In conclusion, pulvinus bending followed both light intensity and air temperature and influenced leaf gas exchange.

  14. Temperature distribution of air source heat pump barn with different air flow

    NASA Astrophysics Data System (ADS)

    He, X.; Li, J. C.; Zhao, G. Q.

    2016-08-01

    There are two type of airflow form in tobacco barn, one is air rising, the other is air falling. They are different in the structure layout and working principle, which affect the tobacco barn in the distribution of temperature field and velocity distribution. In order to compare the temperature and air distribution of the two, thereby obtain a tobacco barn whose temperature field and velocity distribution are more uniform. Taking the air source heat pump tobacco barn as the investigated subject and establishing relevant mathematical model, the thermodynamics of the two type of curing barn was analysed and compared based on Fluent. Provide a reasonable evidence for chamber arrangement and selection of outlet for air source heat pump tobacco barn.

  15. 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

  16. Spatial and Temporal Effects of Free-Air CO2 Enrichment (POPFACE) on Leaf Growth, Cell Expansion, and Cell Production in a Closed Canopy of Poplar1

    PubMed Central

    Taylor, Gail; Tricker, Penny J.; Zhang, Fang Z.; Alston, Victoria J.; Miglietta, Franco; Kuzminsky, Elena

    2003-01-01

    Leaf expansion in the fast-growing tree, Populus × euramericana was stimulated by elevated [CO2] in a closed-canopy forest plantation, exposed using a free air CO2 enrichment technique enabling long-term experimentation in field conditions. The effects of elevated [CO2] over time were characterized and related to the leaf plastochron index (LPI), and showed that leaf expansion was stimulated at very early (LPI, 0–3) and late (LPI, 6–8) stages in development. Early and late effects of elevated [CO2] were largely the result of increased cell expansion and increased cell production, respectively. Spatial effects of elevated [CO2] were also marked and increased final leaf size resulted from an effect on leaf area, but not leaf length, demonstrating changed leaf shape in response to [CO2]. Leaves exhibited a basipetal gradient of leaf development, investigated by defining seven interveinal areas, with growth ceasing first at the leaf tip. Interestingly, and in contrast to other reports, no spatial differences in epidermal cell size were apparent across the lamina, whereas a clear basipetal gradient in cell production rate was found. These data suggest that the rate and timing of cell production was more important in determining leaf shape, given the constant cell size across the leaf lamina. The effect of elevated [CO2] imposed on this developmental gradient suggested that leaf cell production continued longer in elevated [CO2] and that basal increases in cell production rate were also more important than altered cell expansion for increased final leaf size and altered leaf shape in elevated [CO2]. PMID:12529526

  17. 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…

  18. The effect of wind velocity, air temperature and humidity on NH 3 and SO 2 transfer into bean leaves ( phaseolus vulgaris L.)

    NASA Astrophysics Data System (ADS)

    van Hove, L. W. A.; Vredenberg, W. J.; Adema, E. H.

    The influence of wind velocity, air temperature and vapour pressure deficit of the air (VPD) on NH 3 and SO 2 transfer into bean leaves ( Phaseolus vulgaris L.) was examined using a leaf chamber. The measurements suggested a transition in the properties of the leaf boundary layer at a wind velocity of 0.3-0.4 ms -1 which corresponds to a Recrit value of about 2000. At higher wind velocities the leaf boundary layer resistance ( rb) was 1.5-2 times lower than can be calculated from the theory. Nevertheless, the assessed relationships between rb and wind velocity appeared to be similar to the theoretical derived relationship for rb. The NH 3 flux and in particular the SO 2 flux into the leaf strongly increased at a VPD decline. The increase of the NH 3 flux could be attributed to an increase of the stomatal conductance ( gs). However, the increase of the SO 2 flux could only partly be explained by an increase of gs. An apparent additional uptake was also observed for the NH 3 uptake at a low temperature and VPD. The SO 2 flux was also influenced by air temperature which could be explained by a temperature effect on gs. The results suggest that calculation of the NH 3 and SO 2 flux using data of gs gives a serious understimation of the real flux of these gases into leaves at a low temperature and VPD.

  19. Temperature effect on titanium nitride nanometer thin film in air

    NASA Astrophysics Data System (ADS)

    Cen, Z. H.; Xu, B. X.; Hu, J. F.; Ji, R.; Toh, Y. T.; Ye, K. D.; Hu, Y. F.

    2017-02-01

    Titanium nitride (TiN) is a promising alternative plasmonic material to conventional novel metals. For practical plasmonic applications under the influence of air, the temperature-dependent optical properties of TiN thin films in air and its volume variation are essential. Ellipsometric characterizations on a TiN thin film at different increasing temperatures in ambient air were conducted, and optical constants along with film thickness were retrieved. Below 200 °C, the optical properties varied linearly with temperature, in good agreement with other temperature dependent studies of TiN films in vacuum. The thermal expansion coefficient of the TiN thin film was determined to be 10.27  ×  10‑6 °C‑1. At higher temperatures, the TiN thin film gradually loses its metallic characteristics and has weaker optical absorption, impairing its plasmonic performance. In addition, a sharp increase in film thickness was observed at the same time. Changes in the optical properties and film thickness with temperatures above 200 °C were revealed to result from TiN oxidation in air. For the stability of TiN-based plasmonic devices, operation temperatures of lower than 200 °C, or measures to prevent oxidation, are required. The present study is important to fundamental physics and technological applications of TiN thin films.

  20. Soil temperature prediction from air temperature for alluvial soils in lower Indo-Gangetic plain

    NASA Astrophysics Data System (ADS)

    Barman, D.; Kundu, D. K.; Pal, Soumen; Pal, Susanto; Chakraborty, A. K.; Jha, A. K.; Mazumdar, S. P.; Saha, R.; Bhattacharyya, P.

    2017-01-01

    Soil temperature is an important factor in biogeochemical processes. On-site monitoring of soil temperature is limited in spatiotemporal scale as compared to air temperature data inventories due to various management difficulties. Therefore, empirical models were developed by taking 30-year long-term (1985-2014) air and soil temperature data for prediction of soil temperatures at three depths (5, 15, 30 cm) in morning (0636 Indian standard time) and afternoon (1336 Indian standard time) for alluvial soils in lower Indo-Gangetic plain. At 5 cm depth, power and exponential regression models were best fitted for daily data in morning and afternoon, respectively, but it was reverse at 15 cm. However, at 30 cm, exponential models were best fitted for both the times. Regression analysis revealed that in morning for all three depths and in afternoon for 30 cm depth, soil temperatures (daily, weekly, and monthly) could be predicted more efficiently with the help of corresponding mean air temperature than that of maximum and minimum. However, in afternoon, prediction of soil temperature at 5 and 15 cm depths were more precised for all the time intervals when maximum air temperature was used, except for weekly soil temperature at 15 cm, where the use of mean air temperature gave better prediction.

  1. Leaf growth dynamics in four plant species of the Patagonian Monte, Argentina.

    PubMed

    Campanella, M Victoria; Bertiller, Mónica B

    2013-07-01

    Studying plant responses to environmental variables is an elemental key to understand the functioning of arid ecosystems. We selected four dominant species of the two main life forms. The species selected were two evergreen shrubs: Larrea divaricata and Chuquiraga avellanedae and two perennial grasses: Nassella tenuis and Pappostipa speciosa. We registered leaf/shoot growth, leaf production and environmental variables (precipitation, air temperature, and volumetric soil water content at two depths) during summer-autumn and winter-spring periods. Multiple regressions were used to test the predictive power of the environmental variables. During the summer-autumn period, the strongest predictors of leaf/shoot growth and leaf production were the soil water content of the upper layer and air temperature while during the winter-spring period, the strongest predictor was air temperature. In conclusion, we found that the leaf/shoot growth and leaf production were associated with current environmental conditions, specially to soil water content and air temperature.

  2. Correlation of air temperature above water-air sections with the forecasted low level clouds

    NASA Astrophysics Data System (ADS)

    Huseynov, N. Sh.; Malikov, B. M.

    2009-04-01

    As a case study approach the development of low clouds forecasting methods in correlation with air temperature transformational variations on the sections "water-air" is surveyed. It was evident, that transformational variations of air temperature mainly depend on peculiarities and value of advective variations of temperature. DT is the differences of initial temperature on section water-air in started area, from contrast temperature of water surface along a trajectory of movement of air masses and from the temperature above water surface in a final point of a trajectory. Main values of transformational variations of air temperature at advection of a cold masses is 0.530C•h, and at advection of warm masses is -0.370C•h. There was dimensionless quantity K determined and implemented into practice which was characterized with difference of water temperature in forecasting point and air temperature in an initial point in the ratio of dew-points deficiency at the forecasting area. It follows, that the appropriate increasing or decreasing of K under conditions of cold and warm air masses advection, contributes decreasing of low clouds level. References: Abramovich K.G.: Conditions of development and forecasting of low level clouds. vol. #78, 124 pp., Hydrometcenter USSR 1973. Abramovich K.G.: Variations of low clouds level // Meteorology and Hydrology, vol. # 5, 30-41, Moscow, 1968. Budiko M.I.: Empirical assessment of climatic changes toward the end of XX century // Meteorology and Hydrology, vol. #12, 5-13, Moscow, 1999. Buykov M.V.: Computational modeling of daily evolutions of boundary layer of atmosphere at the presence of clouds and fog // Meteorology and Hydrology, vol. # 4, 35-44, Moscow, 1981. Huseynov N.Sh. Transformational variations of air temperature above Caspian Sea / Proceedings of Conference On Climate And Protection of Environment, 118-120, Baku, 1999. Huseynov N.Sh.: Consideration of advective and transformational variations of air temperature in

  3. [Leaf micro-morphology and features in adsorbing air suspended particulate matter and accumulating heavy metals in seven trees species].

    PubMed

    Liu, Ling; Fang, Yan-Ming; Wang, Shun-Chang; Xie, Ying; Yang, Dan-Dan

    2013-06-01

    The purpose of this study was to assess the relationship between tree leaf micro-morphology and features in adsorbing air suspended particulate matter and accumulating heavy metals. Seven tree species, including Ginkgo biloba, at heavy traffic density site in Huainan were selected to analyze the frequency of air particulate matter retained by leaves, the particle amount of different sizes per unit leaf area retained by leaves and its related micro-morphology structure, and the relationship between particle amount of different sizes per unit leaf area retained by leaves and its related accumulation of heavy metals. We found that the species characterized by small leaf area, special epidemis with abundant fax, and highly uneven cell wall, as well as big and dense stomata and without trichomes mainly absorbed fine particulate matter; while those species with many trichomes mainly retained coarse particulate matter. Accumulation of heavy metals in leaves of the seven species was significantly different except for Ph. Tree species with high capacities in heavy metal accumulation were Ginkgo biloba, Ligustrum lucidum, and Cinnamomum camphora. Accumulation of Cd, Cr, Ni, Zn, Cu and total heavy metal concentration for seven tree species was positively related to the amount of particulate matter absorbed. Correlation coefficients of d10 vs d2.5, d10 vs d1.0, d2.5 vs d1.0 were 0.987, 0.971, 0.996, respective, and the correlate level was significant. The ratios of d2.5/d10, d1.0/d10, d1.0/d2.5 were 0.844, 0.763, 0.822, indicating that the particulate matter from traffic was mainly fine particulates.

  4. 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.

  5. AIRS Sea Surface Temperature and Pacific Decadal Oscillation

    NASA Astrophysics Data System (ADS)

    Chen, L. L.

    2015-12-01

    Atmospheric Infrared Sounder (AIRS) has been providing necessary measurements for long term atmospheric and surface processes aboard NASA' s Aqua polar orbiter since May 2002. Here, we use time series of AIRS sea surface temperature (SST) anomalies to show the time evolution of Pacific Decadal Oscillation (PDO) in the Gulf of Alaska (lon:-144.5, lat:54.5) from 2003 to 2014. PDO is connected to the first mode of North Pacific SST variability and is tele-connected to ENSO in the tropics. Further analysis of AIRS data can provide clarification of Pacific climate variability.

  6. 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.

  7. Leaf photosynthesis and respiration of three bioenergy crops in relation to temperature and leaf nitrogen: how conserved are biochemical model parameters among crop species?

    PubMed

    Archontoulis, S V; Yin, X; Vos, J; Danalatos, N G; Struik, P C

    2012-01-01

    Given the need for parallel increases in food and energy production from crops in the context of global change, crop simulation models and data sets to feed these models with photosynthesis and respiration parameters are increasingly important. This study provides information on photosynthesis and respiration for three energy crops (sunflower, kenaf, and cynara), reviews relevant information for five other crops (wheat, barley, cotton, tobacco, and grape), and assesses how conserved photosynthesis parameters are among crops. Using large data sets and optimization techniques, the C(3) leaf photosynthesis model of Farquhar, von Caemmerer, and Berry (FvCB) and an empirical night respiration model for tested energy crops accounting for effects of temperature and leaf nitrogen were parameterized. Instead of the common approach of using information on net photosynthesis response to CO(2) at the stomatal cavity (A(n)-C(i)), the model was parameterized by analysing the photosynthesis response to incident light intensity (A(n)-I(inc)). Convincing evidence is provided that the maximum Rubisco carboxylation rate or the maximum electron transport rate was very similar whether derived from A(n)-C(i) or from A(n)-I(inc) data sets. Parameters characterizing Rubisco limitation, electron transport limitation, the degree to which light inhibits leaf respiration, night respiration, and the minimum leaf nitrogen required for photosynthesis were then determined. Model predictions were validated against independent sets. Only a few FvCB parameters were conserved among crop species, thus species-specific FvCB model parameters are needed for crop modelling. Therefore, information from readily available but underexplored A(n)-I(inc) data should be re-analysed, thereby expanding the potential of combining classical photosynthetic data and the biochemical model.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. Nutrient solution cooling and its effect on temperature of leaf lettuce in hydroponic system.

    PubMed

    Nam, S W; Kim, M K; Son, J E

    1996-12-01

    The heat transfer characteristics of a hydroponic system were experimentally verified after theoretical establishment and the effect of nutrient solution cooling on the plant temperature was investigated. About 96 percent of the total heat flow transferred from culture bed to nutrient solution was the conductive heat through planting board and partitioning materials. The average and maximum temperatures of the leaf lettuce decreased 0.6 and 1.5 degrees C., respectively, with cooling of nutrient solution by 6 degrees C. A numerical model for prediction of cooling load of nutrient solution in a hydroponic greenhouse was developed, and the results from the simulation model showed a good agreement with those from experiments. A mechanical cooling system using the counter flow type with double pipes was developed for cooling the nutrient solution. Also the heat transfer characteristics of the system were analyzed experimentally and theoretically, and compared with the other existing cooling systems of nutrient solution. The cooling capacities of three different systems, which used polyethylene tube in solution tank, stainless tube in solution tank, and the counter flow type with double pipes, were comparatively evaluated.

  13. Sensitivity of Leaf Area Index to Temperature Simulation in the FSUNRSM

    NASA Astrophysics Data System (ADS)

    Goto, Y.; Shin, D.; O'Brien, J. J.

    2006-05-01

    In this research, sensitivity of LAI (Leaf Area Index) to modeled temperatures is investigated replacing prescribed monthly LAI in CLM2 (Community Land Model 2.0) with an LAI dataset derived from observation by MODIS (Moderate Resolution Imaging Spectroradiometer). The prescribed monthly LAI in CLM2 is based on NDVI data from AVHRR (Advanced Very High Resolution Radiometer) during the period of 1981 to 1991, while the LAI by MODIS started in 2000 is directly derived from the observation and also it represents more recent vegetation. For the atmospheric simulation, the current version of FSUGSM (Florida State University Global Spectral Model) and FSUNRSM (Florida State University Nested Regional Spectral Model) coupled with CLM2 are used and the Southeast U.S. is selected as the domain. According to previous researches, FSUNRSM results in Southeast U.S. tend to have a cold bias in the South Florida. The prescribed LAI of the South Florida in CLM2 is significantly lower than the observed LAI by MODIS. In general, low LAI represents low vegetation which implies that less absorption of solar energy in the region. Thus, the more accurate LAI is expected to improve the FSUNRSM, because the low temperature in the region may be due to the LAI representing low vegetation. For the first experiment, the prescribed monthly LAI is adjusted to the LAI based on the MODIS observation in summer to simulate temperatures in the Southeast US. The result shows that calculated temperatures in the South Florida tend to be higher than the original simulations. For the second experiment to calculate summer, the prescribed LAI is replaced with a climatological monthly LAI dataset based on the MODIS observation.

  14. An Optimization Approach to Analyzing the Effect of Supply Water and Air Temperatures in Planning an Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Karino, Naoki; Shiba, Takashi; Yokoyama, Ryohei; Ito, Koichi

    In planning an air conditioning system, supply water and air temperatures are important factors from the viewpoint of cost reduction. For example, lower temperature supply water and air reduce the coefficient of performance of a refrigeration machine, and increase the thickness of heat insulation material. However, they enable larger temperature differences, and reduce equipment sizes and power demand. The purposes of this paper are to propose an optimal planning method for a cold air distribution system, and to analyze the effect of supply water and air temperatures on the long-term economics through a numerical study for an office building. As a result, it is shown that the proposed method effectively determines supply water and air temperatures for a cold air distribution system, and that the influence of supply air temperature is larger than that of supply water temperature on the long-term economics.

  15. Emissions of volatile organic compounds and leaf structural characteristics of European aspen (Populus tremula) grown under elevated ozone and temperature.

    PubMed

    Hartikainen, Kaisa; Nerg, Anne-Marja; Kivimäenpää, Minna; Kontunen-Soppela, Sari; Mäenpää, Maarit; Oksanen, Elina; Rousi, Matti; Holopainen, Toini

    2009-09-01

    Northern forest trees are challenged to adapt to changing climate, including global warming and increasing tropospheric ozone (O(3)) concentrations. Both elevated O(3) and temperature can cause significant changes in volatile organic compound (VOC) emissions as well as in leaf anatomy that can be related to adaptation or increased stress tolerance, or are signs of damage. Impacts of moderately elevated O(3) (1.3x ambient) and temperature (ambient + 1 degrees C), alone and in combination, on VOC emissions and leaf structure of two genotypes (2.2 and 5.2) of European aspen (Populus tremula L.) were studied in an open-field experiment in summer 2007. The impact of O(3) on measured variables was minor, but elevated temperature significantly increased emissions of total monoterpenes and green leaf volatiles. Genotypic differences in the responses to warming treatment were also observed. alpha-Pinene emission, which has been suggested to protect plants from elevated temperature, increased from genotype 5.2 only. Isoprene emission from genotype 2.2 decreased, whereas genotype 5.2 was able to retain high isoprene emission level also under elevated temperature. Elevated temperature also caused formation of thinner leaves, which was related to thinning of epidermis, palisade and spongy layers as well as reduced area of palisade cells. We consider aspen genotype 5.2 to have better potential for adaptation to increasing temperature because of thicker photosynthetic active palisade layer and higher isoprene and alpha-pinene emission levels compared to genotype 2.2. Our results show that even a moderate elevation in temperature is efficient enough to cause notable changes in VOC emissions and leaf structure of these aspen genotypes, possibly indicating the effort of the saplings to adapt to changing climate.

  16. Hormonal regulation of leaf senescence in Lilium.

    PubMed

    Arrom, Laia; Munné-Bosch, Sergi

    2012-10-15

    In addition to floral senescence and longevity, the control of leaf senescence is a major factor determining the quality of several cut flowers, including Lilium, in the commercial market. To better understand the physiological process underlying leaf senescence in this species, we evaluated: (i) endogenous variation in the levels of phytohormones during leaf senescence, (ii) the effects of leaf darkening in senescence and associated changes in phytohormones, and (iii) the effects of spray applications of abscisic acid (ABA) and pyrabactin on leaf senescence. Results showed that while gibberellin 4 (GA(4)) and salicylic acid (SA) contents decreased, that of ABA increased during the progression of leaf senescence. However, dark-induced senescence increased ABA levels, but did not affect GA(4) and SA levels, which appeared to correlate more with changes in air temperature and/or photoperiod than with the induction of leaf senescence. Furthermore, spray applications of pyrabactin delayed the progression of leaf senescence in cut flowers. Thus, we conclude that (i) ABA plays a major role in the regulation of leaf senescence in Lilium, (ii) darkness promotes leaf senescence and increases ABA levels, and (iii) exogenous applications of pyrabactin inhibit leaf senescence in Lilium, therefore suggesting that it acts as an antagonist of ABA in senescing leaves of cut lily flowers.

  17. Arctic air may become cleaner as temperatures rise

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2011-10-01

    The air in the Arctic is cleaner during summer than during winter. Previous studies have shown that for light-scattering pollutants, this seasonal cycle is due mainly to summer precipitation removing pollutants from the air during atmospheric transport from midlatitude industrial and agricultural sources. With new measurements from Barrow, Alaska, and Alert, Nunavut, Canada, Garrett et al. extended previous research to show that light-absorbing aerosols such as black carbon are also efficiently removed by seasonal precipitation. Precipitation removes these particles from the air most efficiently at high humidities and relatively warm temperatures, suggesting that as the Arctic gets warmer and wetter in the future, the air and snow might also become cleaner.

  18. Leaf anatomical and photosynthetic acclimation to cool temperature and high light in two winter versus two summer annuals.

    PubMed

    Cohu, Christopher M; Muller, Onno; Adams, William W; Demmig-Adams, Barbara

    2014-09-01

    Acclimation of foliar features to cool temperature and high light was characterized in winter (Spinacia oleracea L. cv. Giant Nobel; Arabidopsis thaliana (L.) Heynhold Col-0 and ecotypes from Sweden and Italy) versus summer (Helianthus annuus L. cv. Soraya; Cucurbita pepo L. cv. Italian Zucchini Romanesco) annuals. Significant relationships existed among leaf dry mass per area, photosynthesis, leaf thickness and palisade mesophyll thickness. While the acclimatory response of the summer annuals to cool temperature and/or high light levels was limited, the winter annuals increased the number of palisade cell layers, ranging from two layers under moderate light and warm temperature to between four and five layers under cool temperature and high light. A significant relationship was also found between palisade tissue thickness and either cross-sectional area or number of phloem cells (each normalized by vein density) in minor veins among all four species and growth regimes. The two winter annuals, but not the summer annuals, thus exhibited acclimatory adjustments of minor vein phloem to cool temperature and/or high light, with more numerous and larger phloem cells and a higher maximal photosynthesis rate. The upregulation of photosynthesis in winter annuals in response to low growth temperature may thus depend on not only (1) a greater volume of photosynthesizing palisade tissue but also (2) leaf veins containing additional phloem cells and presumably capable of exporting a greater volume of sugars from the leaves to the rest of the plant.

  19. Retrieval of Component Temperatures of Leaf, Sunlit and Shaded Soil in Maize Canopy Based on Airborne Thermal Infrared Multiangular Observations

    NASA Astrophysics Data System (ADS)

    Li, H.; Yongming, D.; Bian, Z.; Cao, B.; Xiao, Q.; Liu, Q.

    2015-12-01

    Land surface temperature is the key parameter to determine land surface energy budget. Due to land surface rugged geometric structure and different components, pixels in the remote sensing image measured from space are often non-isothermal. Several approaches of decomposing temperatures have been developed recent years. These approaches only focus on two components, soil and leaf. In fact ground-based measurements indicate temperatures of sunlit and shaded leaf are nearly the same while temperatures of sunlit and shaded soil are different significantly. In order to retrieve three component temperatures including leaf, sunlit soil and shaded soil, an analytical parameterized model named FR97 was modified in this paper. The modified FR97 model was calibrated by 4SAIL (Scattering by Arbitrarily Inclined Leaves) model. Bayesian algorithm was used to solve the inversion problem. Finally the inversion algorithm was verified by the airborne observed datasets of Wide-angle Infrared Dual mode line / area Array Scanner (WIDAS) over dense maize area during the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) campaign. The results indicate that the modified FR97 model improves a lot for hotspot effect than original FR97 model. And more accurate component temperatures were retrieved especially for sunlit soil component (RMSE = 1.378°C).

  20. 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.

  1. 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.

  2. 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.

  3. Discovery about temperature fluctuations in turbulent air flows

    NASA Astrophysics Data System (ADS)

    1985-02-01

    The law of spatial fluctuations of temperature in a turbulent flow in the atmosphere was studied. The turbulent movement of air in the atmosphere manifests itself in random changes in wind velocity and in the dispersal of smoke. If a miniature thermometer with sufficient sensitivity and speed of response were placed in a air flow, its readings would fluctuate chaotically against the background of average temperature. This is Characteristic of practically every point of the flow. The temperature field forms as a result of the mixing of the air. A method using the relation of the mean square of the difference in temperatures of two points to the distance between these points as the structural characteristic of this field was proposed. It was found that the dissipation of energy in a flow and the equalization of temperatures are connected with the breaking up of eddies in a turbulent flow into smaller ones. Their energy in turn is converted into heat due to the viscosity of the medium. The law that has been discovered makes for a much broader field of application of physical methods of analyzing atmospheric phenomena.

  4. Assessment of two-temperature kinetic model for ionizing air

    NASA Technical Reports Server (NTRS)

    Park, Chul

    1987-01-01

    A two-temperature chemical-kinetic model for air is assessed by comparing theoretical results with existing experimental data obtained in shock-tubes, ballistic ranges, and flight experiments. In the model, named the TTv model, one temperature (T) is assumed to characterize the heavy-particle translational and molecular rotational energies, and another temperature (Tv) to characterize the molecular vibrational, electron translational, and electronic excitation energies. The theoretical results for nonequilibrium air flow in shock tubes are obtained using the computer code STRAP (Shock-Tube Radiation Program), and for flow along the stagnation streamline in the shock layer over spherical bodies using the newly developed code STRAP (Stagnation-Point Radiation Program). Substantial agreement is shown between the theoretical and experimental results for relaxation times and radiative heat fluxes. At very high temperatures the spectral calculations need further improvement. The present agreement provides strong evidence that the two-temperature model characterizes principal features of nonequilibrium air flow. New theoretical results using the model are presented for the radiative heat fluxes at the stagnation point of a 6-m-radius sphere, representing an aeroassisted orbital transfer vehicle, over a range of free-stream conditions. Assumptions, approximations, and limitations of the model are discussed.

  5. The mass and speed dependence of meteor air plasma temperatures.

    PubMed

    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.

  6. 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.

  7. Global Climatic Controls On Leaf Size

    NASA Astrophysics Data System (ADS)

    Wright, I. J.; Prentice, I. C.; Dong, N.; Maire, V.

    2015-12-01

    Since the 1890s it's been known that the wet tropics harbour plants with exceptionally large leaves. Yet the observed latitudinal gradient of leaf size has never been fully explained: it is still unclear which aspects of climate are most important for understanding geographic trends in leaf size, a trait that varies many thousand-fold among species. The key is the leaf-to-air temperature difference, which depends on the balance of energy inputs (irradiance) and outputs (transpirational cooling, losses to the night sky). Smaller leaves track air temperatures more closely than larger leaves. Widely cited optimality-based theories predict an advantage for smaller leaves in dry environments, where transpiration is restricted, but are silent on the latitudinal gradient. We aimed to characterize and explain the worldwide pattern of leaf size. Across 7900 species from 651 sites, here we show that: large-leaved species predominate in wet, hot, sunny environments; smaller-leaved species typify hot, sunny environments only when arid; small leaves are required to avoid freezing in high latitudes and at high elevation, and to avoid overheating in dry environments. This simple pattern was unclear in earlier, more limited analyses. We present a simple but robust, fresh approach to energy-balance modelling for both day-time and night-time leaf-to-air temperature differences, and thus risk of overheating and of frost damage. Our analysis shows night-chilling is important as well as day-heating, and simplifies leaf temperature modelling. It provides both a framework for modelling leaf size constraints, and a solution to one of the oldest conundrums in ecology. Although the path forward is not yet fully clear, because of its role in controlling leaf temperatures we suggest that climate-related leaf size constraints could usefully feature in the next generation of land ecosystem models.

  8. Response of Leaf Hydraulic Conductance to Changes in Atmospheric CO2 and Temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because plants play a central role in the terrestrial hydrologic cycle, it is critical to understand the impact of global change factors on the flux of water through plants. Leaves account for a large portion of the resistance to water flow through the whole plant. Leaf hydraulic conductance (K-leaf...

  9. 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.

  10. 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.

  11. Impacts of Lowered Urban Air Temperatures on Precursor Emission and Ozone Air Quality.

    PubMed

    Taha, Haider; Konopacki, Steven; Akbari, Hashem

    1998-09-01

    Meteorological, photochemical, building-energy, and power plant simulations were performed to assess the possible precursor emission and ozone air quality impacts of decreased air temperatures that could result from implementing the "cool communities" concept in California's South Coast Air Basin (SoCAB). Two pathways are considered. In the direct pathway, a reduction in cooling energy use translates into reduced demand for generation capacity and, thus, reduced precursor emissions from electric utility power plants. In the indirect pathway, reduced air temperatures can slow the atmospheric production of ozone as well as precursor emission from anthropogenic and biogenic sources. The simulations suggest small impacts on emissions following implementation of cool communities in the SoCAB. In summer, for example, there can be reductions of up to 3% in NOx emissions from in-basin power plants. The photochemical simulations suggest that the air quality impacts of these direct emission reductions are small. However, the indirect atmospheric effects of cool communities can be significant. For example, ozone peak concentrations can decrease by up to 11% in summer and population-weighted exceedance exposure to ozone above the California and National Ambient Air Quality Standards can decrease by up to 11 and 17%, respectively. The modeling suggests that if these strategies are combined with others, such as mobile-source emission control, the improvements in ozone air quality can be substantial.

  12. 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

  13. Effects of Eucommia leaf extracts on autonomic nerves, body temperature, lipolysis, food intake, and body weight.

    PubMed

    Horii, Yuko; Tanida, Mamoru; Shen, Jiao; Hirata, Tetsuya; Kawamura, Naomi; Wada, Atsunori; Nagai, Katsuya

    2010-08-02

    Eucommia ulmoides Oliver leaf extracts (ELE) have been shown to exert a hypolipidemic effect in hamsters. Therefore, it was hypothesized that ELE might affect lipid metabolism via changes in autonomic nerve activities and causes changes in thermogenesis and body weight. We examined this hypothesis, and found that intraduodenal (ID) injection of ELE elevated epididymal white adipose tissue sympathetic nerve activity (WAT-SNA) and interscapular brown adipose tissue sympathetic nerve activity (BAT-SNA) in urethane-anesthetized rats and elevated the plasma concentration of free fatty acids (FFA) (a marker of lipolysis) and body temperature (BT) (a marker of thermogenesis) in conscious rats. Furthermore, it was observed that ID administration of ELE decreased gastric vagal nerve activity (GVNA) in urethane-anesthetized rats, and that ELE given as food reduced food intake, body and abdominal adipose tissue weights and decreased plasma triglyceride level. These findings suggest that ELE stimulates lipolysis and thermogenesis through elevations in WAT-SNA and BAT-SNA, respectively, suppresses appetite by inhibiting the activities of the parasympathetic nerves innervating the gastrointestinal tract, including GVNA, and decreases the amount of abdominal fat and body weight via these changes.

  14. Effects of temperature and solvent on antioxidant properties of curry leaf (Murraya koenigii L.).

    PubMed

    Sasidharan, Indu; Menon, A Nirmala

    2011-06-01

    Total polyphenol content (TPC) and antioxidant activities of curry leaf extracts (hexane, chloroform, ethanol, ethanol-water (1:1) and water at ambient (AT, 25 °C) and boiling temperature (BT) (Soxhlet extraction), were determined by DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt), and total reductive potential assays. TPC was in the order ethanol-water (1:1) (AT) > water (AT) > chloroform (AT) > ethanol-water (1:1) (BT) > hexane (AT) > ethanol (BT) > water (BT) > hexane (BT). Ethanol-water (AT) had the maximum TPC of 501 ± 4.6 mg/g GAE and 82% radical scavenging activity (RSA) at 10 μg/ml level (DPPH) and 100% RSA (ABTS) at 10 μg/ml and at hot conditions (ethanol-water (BT)) had less TPC (28.7 ± 0.9%), and 43% RSA by DPPH and 53.6% by ABTS assays. Hot extracts had lesser antioxidant activities than ambient extracts. The best solvent system for getting maximum antioxidant activity from curry leaves was ethanol-water (1:1)-(AT).

  15. Requirements for high-temperature air-cooled central receivers

    NASA Astrophysics Data System (ADS)

    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(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.

  16. Climate change and river temperature sensitivity to warmer nighttime vs. warmer daytime air temperatures

    NASA Astrophysics Data System (ADS)

    Diabat, M.; Haggerty, R.; Wondzell, S. M.

    2011-12-01

    We investigated the July river temperature response to atmospheric warming over the diurnal cycle in a 36 km reach of the upper Middle Fork John Day River of Oregon, USA. The physical model Heat Source was calibrated and used to run 3 different cases of increased air temperature during July: 1) uniform increase over the whole day ("delta method"), 2) warmer daytime, and 3) warmer nighttime. All 3 cases had the same mean daily air temperatures - a 4 °C increase relative to 2002. Results show that the timing of air temperature increases has a significant effect on the magnitude, timing and duration of changes in water temperatures relative to current conditions. In all cases, river temperatures in the lower reach increased by at least 1.1 °C . For the delta case, water temperature increases never exceeded 2.3 °C. In contrast, under the warmer daytime case, water temperature increases exceeded 2.3 °C for 6.6 hours/day on average, with the largest increases occurring during mid-day. In the warmer night case the river temperature increases exceeded 2.3 °C for 4.3 hours/day on average with the largest increases occurring around midnight. In addition, an average increase of 4 °C in air temperature under the delta case increased the water temperature by an average of 1.9 °C uniformly during daytime and nighttime. Still, an average increase of 4 °C in air temperature under the warmer daytime case increased water temperature by an average of at least 1.6 °C during the daytime and by an average of up to 2.5 °C during the nighttime, while an average increase of 4 °C in air temperature under the warmer nighttime case increased the water temperature by an average of at least 1.4 °C during the nighttime and by an average of up to 2.4 °C during the daytime. The spatial response of temperature was different for each case. The lower 13 rkm warmed by at least 1.1 °C with the delta case, while only the lower 6 rkm warmed by at least 1.1 °C with the warmer daytime case

  17. Evaluating CMIP5 models using AIRS tropospheric air temperature and specific humidity climatology

    NASA Astrophysics Data System (ADS)

    Tian, Baijun; Fetzer, Eric J.; Kahn, Brian H.; Teixeira, Joao; Manning, Evan; Hearty, Thomas

    2013-01-01

    This paper documents the climatological mean features of the Atmospheric Infrared Sounder (AIRS) monthly mean tropospheric air temperature (ta, K) and specific humidity (hus, kg/kg) products as part of the Obs4MIPs project and compares them to those from NASA's Modern Era Retrospective analysis for Research and Applications (MERRA) for validation and 16 models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) for CMIP5 model evaluation. MERRA is warmer than AIRS in the free troposphere but colder in the boundary layer with differences typically less than 1 K. MERRA is also drier (~10%) than AIRS in the tropical boundary layer but wetter (~30%) in the tropical free troposphere and the extratropical troposphere. In particular, the large MERRA-AIRS specific humidity differences are mainly located in the deep convective cloudy regions indicating that the low sampling of AIRS in the cloudy regions may be the main reason for these differences. In comparison to AIRS and MERRA, the sixteen CMIP5 models can generally reproduce the climatological features of tropospheric air temperature and specific humidity well, but several noticeable biases exist. The models have a tropospheric cold bias (around 2 K), especially in the extratropical upper troposphere, and a double-ITCZ problem in the troposphere from 1000 hPa to 300 hPa, especially in the tropical Pacific. The upper-tropospheric cold bias exists in the most (13 of 16) models, and the double-ITCZ bias is found in all 16 CMIP5 models. Both biases are independent of the reference dataset used (AIRS or MERRA).

  18. Record low surface air temperature at Vostok station, Antarctica

    NASA Astrophysics Data System (ADS)

    Turner, John; Anderson, Phil; Lachlan-Cope, Tom; Colwell, Steve; Phillips, Tony; Kirchgaessner, AméLie; Marshall, Gareth J.; King, John C.; Bracegirdle, Tom; Vaughan, David G.; Lagun, Victor; Orr, Andrew

    2009-12-01

    The lowest recorded air temperature at the surface of the Earth was a measurement of -89.2°C made at Vostok station, Antarctica, at 0245 UT on 21 July 1983. Here we present the first detailed analysis of this event using meteorological reanalysis fields, in situ observations and satellite imagery. Surface temperatures at Vostok station in winter are highly variable on daily to interannual timescales as a result of the great sensitivity to intrusions of maritime air masses as Rossby wave activity changes around the continent. The record low temperature was measured following a near-linear cooling of over 30 K over a 10 day period from close to mean July temperatures. The event occurred because of five specific conditions that arose: (1) the temperature at the core of the midtropospheric vortex was at a near-record low value; (2) the center of the vortex moved close to the station; (3) an almost circular flow regime persisted around the station for a week resulting in very little warm air advection from lower latitudes; (4) surface wind speeds were low for the location; and (5) no cloud or diamond dust was reported above the station for a week, promoting the loss of heat to space via the emission of longwave radiation. We estimate that should a longer period of isolation occur the surface temperature at Vostok could drop to around -96°C. The higher site of Dome Argus is typically 5-6 K colder than Vostok so has the potential to record an even lower temperature.

  19. Responses of herbaceous plants to urban air pollution: effects on growth, phenology and leaf surface characteristics.

    PubMed

    Honour, Sarah L; Bell, J Nigel B; Ashenden, Trevor W; Cape, J Neil; Power, Sally A

    2009-04-01

    Vehicle exhaust emissions are a dominant feature of urban environments and are widely believed to have detrimental effects on plants. The effects of diesel exhaust emissions on 12 herbaceous species were studied with respect to growth, flower development, leaf senescence and leaf surface wax characteristics. A diesel generator was used to produce concentrations of nitrogen oxides (NO(x)) representative of urban conditions, in solardome chambers. Annual mean NO(x) concentrations ranged from 77 nl l(-l) to 98 nl l(-1), with NO:NO(2) ratios of 1.4-2.2, providing a good experimental simulation of polluted roadside environments. Pollutant exposure resulted in species-specific changes in growth and phenology, with a consistent trend for accelerated senescence and delayed flowering. Leaf surface characteristics were also affected; contact angle measurements indicated changes in surface wax structure following pollutant exposure. The study demonstrated clearly the potential for realistic levels of vehicle exhaust pollution to have direct adverse effects on urban vegetation.

  20. 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.

  1. Temperature Variations Recorded During Interinstitutional Air Shipments of Laboratory Mice

    PubMed Central

    Syversen, Eric; Pineda, Fernando J; Watson, Julie

    2008-01-01

    Despite extensive guidelines and regulations that govern most aspects of rodent shipping, few data are available on the physical environment experienced by rodents during shipment. To document the thermal environment experienced by mice during air shipments, we recorded temperatures at 1-min intervals throughout 103 routine interinstitutional shipments originating at our institution. We found that 49.5% of shipments were exposed to high temperatures (greater than 29.4 °C), 14.6% to low temperatures (less than 7.2 °C), and 61% to temperature variations of 11 °C or more. International shipments were more likely than domestic shipments to experience temperature extremes and large variations in temperature. Freight forwarders using passenger airlines rather than their own airplanes were more likely to have shipments that experienced temperature extremes or variations. Temperature variations were most common during stopovers. Some airlines were more likely than others to experience inflight temperature extremes or swings. Most domestic shipments lasted at least 24 h, whereas international shipments lasted 48 to 72 h. Despite exposure to high and low temperatures, animals in all but 1 shipment arrived alive. We suggest that simple measures, such as shipping at night during hot weather, provision of nesting material in shipping crates, and specifying aircraft cargo-hold temperatures that are suitable for rodents, could reduce temperature-induced stress. Measures such as additional training for airport ground crews, as previously recommended by the American Veterinary Medical Association, could further reduce exposure of rodents to extreme ambient temperatures during airport stopovers. PMID:18210996

  2. 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.

  3. The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests.

    PubMed

    Salinas, N; Malhi, Y; Meir, P; Silman, M; Roman Cuesta, R; Huaman, J; Salinas, D; Huaman, V; Gibaja, A; Mamani, M; Farfan, F

    2011-03-01

    • We present the results from a litter translocation experiment along a 2800-m elevation gradient in Peruvian tropical forests. The understanding of the environmental factors controlling litter decomposition is important in the description of the carbon and nutrient cycles of tropical ecosystems, and in predicting their response to long-term increases in temperature. • Samples of litter from 15 species were transplanted across all five sites in the study, and decomposition was tracked over 448 d. • Species' type had a large influence on the decomposition rate (k), most probably through its influence on leaf quality and morphology. When samples were pooled across species and elevations, soil temperature explained 95% of the variation in the decomposition rate, but no direct relationship was observed with either soil moisture or rainfall. The sensitivity of the decay rate to temperature (κ(T)) varied seven-fold across species, between 0.024 and 0.169 °C⁻¹, with a mean value of 0.118 ± 0.009 °C⁻¹ (SE). This is equivalent to a temperature sensitivity parameter (Q₁₀) for litter decay of 3.06 ± 0.28, higher than that frequently assumed for heterotrophic processes. • Our results suggest that the warming of approx. 0.9 °C experienced in the region in recent decades may have increased decomposition and nutrient mineralization rates by c. 10%.

  4. 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.

  5. 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.

  6. Air pollution effects on the guard cells of the injury resistant leaf of Laurus nobilis L

    SciTech Connect

    Christodoulakis, N.S. )

    1993-09-01

    The need for cleaner air has led to detailed investigations not only on the sources and types of air pollutants but also on the effect that these compounds have on various life forms. The plants are the first [open quotes]victims[close quotes] of the air pollutants. Extensive literature exists on the structural damages and functional problems that plants suffer after being exposed to air pollutants. Many investigators prefer to deal with damages, caused to various organs, in plants growing in non polluted environments, after being fumigated with certain air pollutants. Others investigate the problems in plants growing in polluted areas thus being subject to long-term exposure to air pollutants. Generally it seems that primary producers suffer injuries, most of the time serious, that finally lead to the suppression of photosynthesis with all the undesirable consequences that this situation has for the ecosystem. Unfortunately Athens is not only the most polluted city in Greece but also an example to be avoided among the most polluted cities in the world. Serious problems occur in plants living in this environment. One exception is Laurus nobilis, introduced as an injury resistant species. These researchers studied the plant cells and the structure of their organelles, focusing on the guard cells of the leaves. They occur on the underside of leaves and they are directly affected by polluted air. Studies show that the air pollution injury resistance of Laurus is genetic. 25 refs., 21 figs

  7. Daily Air Temperature and Electricity Load in Spain.

    NASA Astrophysics Data System (ADS)

    Valor, Enric; Meneu, Vicente; Caselles, Vicente

    2001-08-01

    Weather has a significant impact on different sectors of the economy. One of the most sensitive is the electricity market, because power demand is linked to several weather variables, mainly the air temperature. This work analyzes the relationship between electricity load and daily air temperature in Spain, using a population-weighted temperature index. The electricity demand shows a significant trend due to socioeconomic factors, in addition to daily and monthly seasonal effects that have been taken into account to isolate the weather influence on electricity load. The results indicate that the relationship is nonlinear, showing a `comfort interval' of ±3°C around 18°C and two saturation points beyond which the electricity load no longer increases. The analysis has also revealed that the sensitivity of electricity load to daily air temperature has increased along time, in a higher degree for summer than for winter, although the sensitivity in the cold season is always more significant than in the warm season. Two different temperature-derived variables that allow a better characterization of the observed relationship have been used: the heating and cooling degree-days. The regression of electricity data on them defines the heating and cooling demand functions, which show correlation coefficients of 0.79 and 0.87, and predicts electricity load with standard errors of estimate of ±4% and ±2%, respectively. The maximum elasticity of electricity demand is observed at 7 cooling degree-days and 9 heating degree-days, and the saturation points are reached at 11 cooling degree-days and 13 heating degree-days, respectively. These results are helpful in modeling electricity load behavior for predictive purposes.

  8. 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.

  9. Effect of Errors in Measuring Leaf Temperature and Ambient Gas Concentration on Calculated Resistances to CO2 and Water Vapor Exchanges in Plant Leaves

    PubMed Central

    Slatyer, R. O.

    1971-01-01

    Errors as small as 1 C in the measurement of leaf temperature (Tleaf) are shown to cause significant changes in the estimated value of the stomatal resistance (expressed in terms of total resistance to water vapor transfer, ∑rH2O). The effect increases as Tleaf increases and as ambient relative humidity increases, if other conditions are maintained constant. The effect on the key CO2 exchange parameter, the intracellular (or mesophyll) resistance, rint, tends to be small under open stomata conditions but increases rapidly as stomatal closure occurs, particularly if the true value of rint is relatively small. Errors in the determination of the ambient water vapor and CO2 concentrations can also significantly affect the calculated value of ∑rH2O and rint. The effect on ∑rH2O and ∑rCO2 increases as the ratio of the inlet/outlet concentration departs from unity and also increases as the assumed leaf-air concentration difference decreases. The combined effect on rint tends to be less than the individual effects on ∑rH2O and ∑rCO2 since both are in the same direction. PMID:16657607

  10. 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

  11. Air-sea interactions in sea surface temperature frontal region

    NASA Astrophysics Data System (ADS)

    Pianezze, Joris; Redelsperger, Jean-Luc; Ardhuin, Fabrice; Reynaud, Thierry; Marié, Louis; Bouin, Marie-Noelle; Garnier, Valerie

    2015-04-01

    Representation of air-sea exchanges in coastal, regional and global models represent a challenge firstly due to the small scale of acting turbulent processes comparatively to the resolved scales of these models. Beyond this subgrid parameterization issue, a comprehensive understanding of air-sea interactions at the turbulent process scales is still lacking. Many successful efforts are dedicated to measure the energy and mass exchanges between atmosphere and ocean, including the effect of surface waves. In comparison less efforts are brought to understand the interactions between the atmospheric boundary layer and the oceanic mixing layer. In this regard, we are developing research mainly based on ideal and realistic numerical simulations which resolve very small scales (horizontal resolutions from 1 to 100 meters) in using grid nesting technics and coupled ocean-wave-atmosphere models. As a first step, the impact of marked gradients in sea surface temperatures (SST) on air-sea exchanges has been explored through realistic numerical simulations at 100m horizontal resolution. Results from simulations of a case observed during the FROMVAR experiment will be shown. The talk will mainly focus on the marked impact of SST front on the atmospheric boundary layer (stability and winds), the air-sea exchanges and surface parameters (rugosity, drag coefficient) Results will be also shown on the strong impact on the simulated atmosphere of small scale variability of SST field.

  12. 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.

  13. Balancing photosynthetic light-harvesting and light-utilization capacities in potato leaf tissue during acclimation to different growth temperatures

    NASA Technical Reports Server (NTRS)

    Steffen, K. L.; Wheeler, R. M.; Arora, R.; Palta, J. P.; Tibbitts, T. W.

    1995-01-01

    We investigated the effect of temperature during growth and development on the relationship between light-harvesting capacity, indicated by chlorophyll concentration, and light-utilization potential, indicated by light- and bicarbonate-saturated photosynthetic oxygen evolution, in Solanum tuberosum L. cv. Norland. Clonal plantlets were transplanted and grown at 20 degrees C for 2 weeks before transfer to 12, 16, 20, 24 and 28 degrees C for 6 weeks. After 4 weeks of the temperature treatments, leaf tissue fresh weights per area were one-third higher in plants grown at 12 degrees C vs those grown at 28 degrees C. Conversely, chlorophyll content per area in tissue grown at 12 degrees C was less than one-half of that of tissue grown at 28 degrees C at 4 weeks. Photosynthetic capacity measured at a common temperature of 20 degrees C and expressed on a chlorophyll basis was inversely proportional to growth temperature. Leaf tissue from plants grown at 12 degrees C for 4 weeks had photosynthetic rates that were 3-fold higher on a chlorophyll basis than comparable tissue from plants grown at 28 degrees C. These results suggest that the relationship between light-harvesting capacity and light-utilization potential varies 3-fold in response to the growth temperatures examined. The role of this response in avoidance of photoinhibition is discussed.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. Pd-modified Reactive Air Braze for Increased Melting Temperature

    SciTech Connect

    Hardy, John S.; Weil, K. Scott; Kim, Jin Yong Y.; Darsell, Jens T.

    2005-03-01

    Complex high temperature devices such as planar solid oxide fuel cell (pSOFC) stacks often require a two-step sealing process. For example, in pSOFC stacks the oxide ceramic fuel cell plates might be sealed into metallic support frames in one step. Then the frames with the fuel plates sealed to them would be joined together in a separate sealing step to form the fuel cell stack. In this case, the initial seal should have a sufficiently high solidus temperature that it will not begin to remelt at the sealing temperature of the material used for the subsequent sealing step. Previous experience has indicated that, when heated at a rate of 10°C/min, Ag-CuO reactive air braze (RAB) compositions have solidus and liquidus temperatures in the approximate range of 925 to 955°C. Therefore, compositionally modifying the original Ag-CuO braze with Pd-additions such that the solidus temperature of the new braze is between 1025 and 1050°C would provide two RAB compositions with a difference in melting points large enough to allow reactive air brazing of both sets of seals in the fuel cell stack. This study determines the appropriate ratio of Pd to Ag in RAB required to achieve a solidus in the desired range and discusses the wettability of the resulting Pd-Ag-CuO brazes on YSZ substrates. The interfacial microstructures and flexural strengths of Pd-Ag-CuO joints in YSZ will also be presented.

  20. [Impact of canopy structural characteristics on inner air temperature and relative humidity of Koelreuteria paniculata community in summer].

    PubMed

    Qin, Zhong; Li, Zhan-dong; Cheng, Fang-yun; Sha, Hai-feng

    2015-06-01

    To investigate the diurnal variation of the correlations between the cooling and humidifying effects and canopy structural characteristics of the Koelreuteria paniculata community, the measurements of air temperature, relative humidity, canopy density, leaf area index (LAI) and mean leaf angle (MLA) were performed on calm sunny summer days in the community in Beijing Olympic Forest Park, China. There were significant correlations between the canopy density, LAI and MLA, which affected the cooling and humidifying effects together. The cooling effect reached its maximum by 12:00, whereas the humidifying effect reached its peak at 10:00. Compared with the control open space site, the community appeared to lower the air temperature by 0.43 to 7.53 °C and to increase the relative humidity by 1%-22% during the daytime. However, the cooling and humidifying effects seem to be not effective during the night. The canopy density and LAI were better for determining the cooling and humidifying effects from 9:00 to 12:00. However, these effects were largely controlled only by the canopy density from 12:00 to 14:00 and were significantly correlated with the canopy density and LAI afterwards until 18:00.

  1. Model-based estimation of changes in air temperature seasonality

    NASA Astrophysics Data System (ADS)

    Barbosa, Susana; Trigo, Ricardo

    2010-05-01

    Seasonality is a ubiquitous feature in climate time series. Climate change is expected to involve not only changes in the mean of climate parameters but also changes in the characteristics of the corresponding seasonal cycle. Therefore the identification and quantification of changes in seasonality is a highly relevant topic in climate analysis, particularly in a global warming context. However, the analysis of seasonality is far from a trivial task. A key challenge is the discrimination between long-term changes in the mean and long-term changes in the seasonal pattern itself, which requires the use of appropriate statistical approaches in order to be able to distinguish between overall trends in the mean and trends in the seasons. Model based approaches are particularly suitable for the analysis of seasonality, enabling to assess uncertainties in the amplitude and phase of seasonal patterns within a well defined statistical framework. This work addresses the changes in the seasonality of air temperature over the 20th century. The analysed data are global air temperature values close to surface (2m above ground) and mid-troposphere (500 hPa geopotential height) from the recently developed 20th century reanalysis. This new 3-D Reanalysis dataset is available since 1891, considerably extending all other Reanalyses currently in use (e.g. NCAR, ECWMF), and was obtained with the Ensemble Filter (Compo et al., 2006) by assimilation of pressure observations into a state-of-the-art atmospheric general circulation model that includes the radiative effects of historical time-varying CO2 concentrations, volcanic aerosol emissions and solar output variations. A modeling approach based on autoregression (Barbosa et al, 2008; Barbosa, 2009) is applied within a Bayesian framework for the estimation of a time varying seasonal pattern and further quantification of changes in the amplitude and phase of air temperature over the 20th century. Barbosa, SM, Silva, ME, Fernandes, MJ

  2. Transpiration and Leaf Temperature. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Gates, David M.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This report introduces two models of the thermal energy budget of a leaf. Typical values for…

  3. 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.

  4. DDT in fuel air mixtures at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Card, J.; Rival, D.; Ciccarelli, G.

    2005-11-01

    An experimental study was carried out to investigate flame acceleration and deflagration-to-detonation transition (DDT) in fuel air mixtures at initial temperatures up to 573 K and pressures up to 2 atm. The fuels investigated include hydrogen, ethylene, acetylene and JP-10 aviation fuel. The experiments were performed in a 3.1-m long, 10-cm inner-diameter heated detonation tube equipped with equally spaced orifice plates. Ionization probes were used to measure the flame time-of-arrival from which the average flame velocity versus propagation distance could be obtained. The DDT composition limits and the distance required for the flame to transition to detonation were obtained from this flame velocity data. The correlation developed by Veser et al. (run-up distance to supersonic flames in obstacle-laden tubes. In the proceedings of the 4th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions, France (2002)) for the flame choking distance proved to work very well for correlating the detonation run-up distance measured in the present study. The only exception was for the hydrogen air data at elevated initial temperatures which tended to fall outside the scatter of the hydrocarbon mixture data. The DDT limits obtained at room temperature were found to follow the classical d/λ = 1 correlation, where d is the orifice plate diameter and λ is the detonation cell size. Deviations found for the high-temperature data could be attributed to the one-dimensional ZND detonation structure model used to predict the detonation cell size for the DDT limit mixtures. This simple model was used in place of actual experimental data not currently available.

  5. Spatial and temporal changes in leaf coloring date of Acer palmatum and Ginkgo biloba in response to temperature increases in South Korea

    PubMed Central

    Park, Chang-Kyun; Ho, Chang-Hoi; Jeong, Su-Jong; Lee, Eun Ju; Kim, Jinwon

    2017-01-01

    Understanding shifts in autumn phenology associated with climate changes is critical for preserving forest ecosystems. This study examines the changes in the leaf coloring date (LCD) of two temperate deciduous tree species, Acer palmatum (Acer) and Ginkgo biloba (Ginkgo), in response to surface air temperature (Ts) changes at 54 stations of South Korea for the period 1989–2007. The variations of Acer and Ginkgo in South Korea are very similar: they show the same mean LCD of 295th day of the year and delays of about 0.45 days year-1 during the observation period. The delaying trend is closely correlated (correlation coefficient > 0.77) with increases in Ts in mid-autumn by 2.8 days °C-1. It is noted that the LCD delaying and temperature sensitivity (days °C-1) for both tree species show negligible dependences on latitudes and elevations. Given the significant LCD-Ts relation, we project LCD changes for 2016–35 and 2046–65 using a process-based model forced by temperature from climate model simulation. The projections indicate that the mean LCD would be further delayed by 3.2 (3.7) days in 2016–35 (2046–65) due to mid-autumn Ts increases. This study suggests that the mid-autumn warming is largely responsible for the observed LCD changes in South Korea and will intensify the delaying trends in the future. PMID:28346534

  6. Spatial and temporal changes in leaf coloring date of Acer palmatum and Ginkgo biloba in response to temperature increases in South Korea.

    PubMed

    Park, Chang-Kyun; Ho, Chang-Hoi; Jeong, Su-Jong; Lee, Eun Ju; Kim, Jinwon

    2017-01-01

    Understanding shifts in autumn phenology associated with climate changes is critical for preserving forest ecosystems. This study examines the changes in the leaf coloring date (LCD) of two temperate deciduous tree species, Acer palmatum (Acer) and Ginkgo biloba (Ginkgo), in response to surface air temperature (Ts) changes at 54 stations of South Korea for the period 1989-2007. The variations of Acer and Ginkgo in South Korea are very similar: they show the same mean LCD of 295th day of the year and delays of about 0.45 days year-1 during the observation period. The delaying trend is closely correlated (correlation coefficient > 0.77) with increases in Ts in mid-autumn by 2.8 days °C-1. It is noted that the LCD delaying and temperature sensitivity (days °C-1) for both tree species show negligible dependences on latitudes and elevations. Given the significant LCD-Ts relation, we project LCD changes for 2016-35 and 2046-65 using a process-based model forced by temperature from climate model simulation. The projections indicate that the mean LCD would be further delayed by 3.2 (3.7) days in 2016-35 (2046-65) due to mid-autumn Ts increases. This study suggests that the mid-autumn warming is largely responsible for the observed LCD changes in South Korea and will intensify the delaying trends in the future.

  7. Impact of Atlantic sea surface temperatures on the warmest global surface air temperature of 1998

    NASA Astrophysics Data System (ADS)

    Lu, Riyu

    2005-03-01

    The year 1998 is the warmest year in the record of instrumental measurements. In this study, an atmospheric general circulation model is used to investigate the role of sea surface temperatures (SSTs) in this warmth, with a focus on the role of the Atlantic Ocean. The model forced with the observed global SSTs captures the main features of land surface air temperature anomalies in 1998. A sensitivity experiment shows that in comparison with the global SST anomalies, the Atlantic SST anomalies can explain 35% of the global mean surface air temperature (GMAT) anomaly, and 57% of the land surface air temperature anomaly in 1998. The mechanisms through which the Atlantic Ocean influences the GMAT are likely different from season to season. Possible detailed mechanisms involve the impact of SST anomalies on local convection in the tropical Atlantic region, the consequent excitation of a Rossby wave response that propagates into the North Atlantic and the Eurasian continent in winter and spring, and the consequent changes in tropical Walker circulation in summer and autumn that induce changes in convection over the tropical Pacific. This in turn affects climate in Asia and Australia. The important role of the Atlantic Ocean suggests that attention should be paid not only to the tropical Pacific Ocean, but also to the tropical Atlantic Ocean in understanding the GMAT variability and its predictability.

  8. 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.

  9. Influence of leaf-to-air vapour pressure deficit (VPD) on the biochemistry and physiology of photosynthesis in Prosopis juliflora.

    PubMed

    Shirke, Pramod A; Pathre, Uday V

    2004-09-01

    The effect of leaf-to-air vapour pressure deficit (VPD) was studied in well-watered, potted, 1-2-year-old plants of the leguminous tree P. juliflora grown outside in northern India. The long-term responses to VPD were analysed from diurnal and seasonal variations in gas exchange parameters measured in two cohorts of leaves produced in February and July, respectively. In general, inhibitory effects of high VPD were visible only when the VPD level exceeded a threshold of >3 kPa. There was a substantial decline in net photosynthesis rate and stomatal conductance at high VPD >4 kPa and transpiration showed a decrease in steady-state rate or feedforward response to VPD. The feedforward responses were visible in all seasons, although the plants were exposed to a wide range of VPD during the year and leaf relative water content was constant. The maximum quantum efficiency of PSII measured predawn was constant (around 0.8) in all seasons except summer. Short-term experiments showed that, although gas exchange was severely affected by high VPD in the leaves of both cohorts, the plant maintained a constant, water use efficiency in different seasons. High VPD also caused reductions in Rubisco activity, affecting carboxylation efficiency, and reductions in sucrose and starch content due to a decrease in the activity of sucrose-phosphate synthase. However, the relative quantum yield of PSII and electron transport rates measured at 1500 micromol m(-2) s(-1) were unaffected by increasing VPD, indicating the presence of a large alternative sink possibly, photorespiration. The overall results showed that P. juliflora can withstand high VPD by reducing metabolic activity and by effective adjustments in the partitioning of electron flow between assimilation and non-assimilation processes, which, in turn, imposed a strong limitation on the potential carbon gain.

  10. [Effects of high temperature on leaf photosynthetic characteristics and photosystem II photochemical activity of kernel-used apricot].

    PubMed

    Du, Guo-dong; Lü, De-guo; Zhao, Ling; Wang, Su-su; Cai, Qian

    2011-03-01

    In order to explore the photosynthetic adaption mechanisms of kernel-used apricot under high temperature stress, gas exchange technique and chlorophyll fluorescence transient technique (JIP-test) were adopted to study the leaf photosynthetic characteristics and photosystem II (PS II) photochemical activity of 4 year-old 'Chaoren' (Armeniaca vulgaris x sibirica) growing on Horqin sandy land at 25 degrees C, 30 degrees C, 40 degrees C, and 50 degrees C. Within a definite temperature range, and as the temperature increased, the 'Chaoren' could enhance its leaf photosynthetic pigments content and ratio to maintain the light absorption, transfer, and conversion, and thereby, to ensure the function of photosynthetic apparatus. However, when the temperature exceeded the physiological adjustment threshold of leaves, the chlorophyll began to be decomposed, net photosynthetic rate (Pn) declined obviously, and intercellular CO2 concentration (Ci) increased, indicating that the decline in photosynthesis was limited by mesophyll factor. At 40 degrees C, the density of PS II reaction centers per excited cross-section (RC/CS0) dropped distinctly; and at 50 degrees C, the K phase (Wk) and J phase (Vj) in the O-J-I-P chlorophyll fluorescence transients increased distinctly, indicating that high temperature damaged the oxygen-evolving complex (OEC), donor sides, and PS II reaction centers. In addition, the minimum chlorophyll fluorescence (F0) at 50 degrees C increased significantly by 1.26 times, compared with the control, and the maximum photochemical efficiency (Fv/Fm) and performance index (PI(ABS)) reduced to 37.9% and 10.3% of the control, respectively. High temperature injured the function of the donor and acceptor sides in the PS II of photosynthetic apparatus, leading to the decrease of photosynthetic efficiency, and being one of the main mechanisms for the damage of photosynthetic apparatus in kernel-used apricot leaves under high temperature stress.

  11. Leaf respiration rates are increased by warm season as well as by elevated temperature treatment in Eucalyptus globulus

    NASA Astrophysics Data System (ADS)

    Ekenstam, Angelica af; Wallin, Göran; Ellsworth, David; Uddling Fredin, Johan; Crous, Kristine

    2014-05-01

    Plant leaf respiration is one of the major CO2 fluxes between terrestrial biosphere and the atmosphere, and its responses to elevated CO2 and temperature thus have important implications for the carbon cycle and rate on ongoing climate change. Non-photorespiratory leaf respiration is reduced in light, Rlight, compared with the rate in the dark, Rdark. It is therefore important to consider both Rlight and Rdark when estimating the exchange of CO2 between the biosphere and the atmosphere, during current and future climates. This study was conducted at the Hawkesbury Forest Experiment, HFE, in Richmond, NSW, Australia. Trees of Tasmanian Blue Gum (Eucalyptus globulus Labill.) were exposed in whole tree chambers (WTC) to a complete factorial combination of ambient and elevated temperature and CO2 (+3 °C and +240 ppm CO2, respectively). The measurements of Rlight and Rdark were made in 2011 after 9 - 15 months exposure in the WTCs. The measurements were made in March (after the year's hottest months) and October (after the coldest period). Rlight was determined at four temperatures ranging between 20 and 40 °C on attached leaves using a portable gas exchange system (LI-6400XT). Rdark was measured at 20-40 °C in October and at 25 °C in March. Rdark was measured after dark acclimation for at least 30 min and Rlight was determined from the intersection of the photosynthetic CO2 responses measured at three different light intensities using the Laisk metod. Trees grown in elevated temperature had a considerably higher Rdark (+53% across all measurement temperatures in October). However, Rlight did not respond significantly to either CO2 or temperature. In October, the Rlight to Rdark ratio indicated an overall light inhibition of respiration of 31% across all temperatures and in March the light inhibition was 22 % at 25 °C. The seasonal comparisons showed that both Rlight and Rdark were considerably higher after the warm compared to cold season, especially when measured

  12. Effectiveness of an air-cooled vest using selected air temperature and humidity combinations.

    PubMed

    Pimental, N A; Cosimini, H M; Sawka, M N; Wenger, C B

    1987-02-01

    We evaluated the effectiveness of an air-cooled vest in reducing thermal strain of subjects exercising in the heat (49 degrees C dry bulb (db), 20 degrees C dew point (dp] in chemical protective clothing. Four male subjects attempted 300-min heat exposures at two metabolic rates (175 and 315 W) with six cooling combinations--control (no vest) and five different db and dp combinations. Air supplied to the vest at 15 scfm ranged from 20-27 degrees C db, 7-18 degrees C dp; theoretical cooling capacities were 498-687 W. Without the vest, endurance times were 118 min (175 W) and 73 min (315 W). Endurance times with the vest were 300 min (175 W) and 242-300 min (315 W). The five cooling combinations were similarly effective in reducing thermal strain and extending endurance time, although there was a trend for the vest to be more effective when supplied with air at the lower dry bulb temperature. At 175 W, subjects maintained a constant body temperature; at 315 W, the vest's ability to extend endurance is limited to about 5 hours.

  13. Leaf-age effects on temperature responses of photosynthesis and respiration of an alpine oak, Quercus aquifolioides, in southwestern China.

    PubMed

    Zhou, Haoran; Xu, Ming; Pan, Hongli; Yu, Xiubo

    2015-11-01

    Temperature responses and sensitivity of photosynthesis (A(n_)T) and respiration for leaves at different ages are crucial to modeling ecosystem carbon (C) cycles and productivity of evergreen forests. Understanding the mechanisms and processes of temperature sensitivity may further shed lights on temperature acclimation of photosynthesis and respiration with leaf aging. The current study examined temperature responses of photosynthesis and respiration of young leaves (YLs) (fully expanded in current growth season) and old leaves (OLs) (fully expanded in last growth season) of Quercus aquifolioides Rehder and E.H. Wilson in an alpine oak forest, southwestern China. Temperature responses of dark respiration (R(dark)), net assimilation (A(n)), maximal velocity of carboxylation (V(cmax)) and maximum rate of electron transport (J(max)) were significantly different between the two leaf ages. Those differences implied different temperature response parameters should be used for leaves of different ages in modeling vegetation productivity and ecosystem C cycles in Q. aquifolioides forests and other evergreen forests. We found that RuBP carboxylation determined the downward shift of A(n_)T in OLs, while RuBP regeneration and the balance between Rubisco carboxylation and RuBP regeneration made little contribution. Sensitivity of stomatal conductance to vapor pressure deficit changed in OLs and compensated part of the downward shift. We also found that OLs of Q. aquifolioides had lower An due to lower stomatal conductance, higher stomatal conductance limitation and deactivation of the biochemical processes. In addition, the balance between R(dark) and A(n) changed between OLs and YLs, which was represented by a higher R(dark)/A(n) ratio for OLs.

  14. 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

  15. 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.

  16. Temperature profile and producer gas composition of high temperature air gasification of oil palm fronds

    NASA Astrophysics Data System (ADS)

    Guangul, F. M.; Sulaiman, S. A.; Ramli, A.

    2013-06-01

    Environmental pollution and scarcity of reliable energy source are the current pressing global problems which need a sustainable solution. Conversion of biomass to a producer gas through gasification process is one option to alleviate the aforementioned problems. In the current research the temperature profile and composition of the producer gas obtained from the gasification of oil palm fronds by using high temperature air were investigated and compared with unheated air. By preheating the gasifying air at 500°C the process temperature were improved and as a result the concentration of combustible gases and performance of the process were improved. The volumetric percentage of CO, CH4 and H2 were improved from 22.49, 1.98, and 9.67% to 24.98, to 2.48% and 13.58%, respectively. In addition, HHV, carbon conversion efficiency and cold gas efficiency were improver from 4.88 MJ/Nm3, 83.8% and 56.1% to 5.90 MJ/Nm3, 87.3% and 62.4%, respectively.

  17. 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.

  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. 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.

  20. A retrieval algorithm to evaluate the Photosystem I and Photosystem II spectral contributions to leaf chlorophyll fluorescence at physiological temperatures.

    PubMed

    Palombi, Lorenzo; Cecchi, Giovanna; Lognoli, David; Raimondi, Valentina; Toci, Guido; Agati, Giovanni

    2011-09-01

    A new computational procedure to resolve the contribution of Photosystem I (PSI) and Photosystem II (PSII) to the leaf chlorophyll fluorescence emission spectra at room temperature has been developed. It is based on the Principal Component Analysis (PCA) of the leaf fluorescence emission spectra measured during the OI photochemical phase of fluorescence induction kinetics. During this phase, we can assume that only two spectral components are present, one of which is constant (PSI) and the other variable in intensity (PSII). Application of the PCA method to the measured fluorescence emission spectra of Ficus benjamina L. evidences that the temporal variation in the spectra can be ascribed to a single spectral component (the first principal component extracted by PCA), which can be considered to be a good approximation of the PSII fluorescence emission spectrum. The PSI fluorescence emission spectrum was deduced by difference between measured spectra and the first principal component. A single-band spectrum for the PSI fluorescence emission, peaked at about 735 nm, and a 2-band spectrum with maxima at 685 and 740 nm for the PSII were obtained. A linear combination of only these two spectral shapes produced a good fit for any measured emission spectrum of the leaf under investigation and can be used to obtain the fluorescence emission contributions of photosystems under different conditions. With the use of our approach, the dynamics of energy distribution between the two photosystems, such as state transition, can be monitored in vivo, directly at physiological temperatures. Separation of the PSI and PSII emission components can improve the understanding of the fluorescence signal changes induced by environmental factors or stress conditions on plants.

  1. Secretome weaponries of Cochliobolus lunatus interacting with potato leaf at different temperature regimes reveal a CL[xxxx]LHM - motif

    PubMed Central

    2014-01-01

    Background Plant and animal pathogenic fungus Cochliobolus lunatus cause great economic damages worldwide every year. C. lunatus displays an increased temperature dependent-virulence to a wide range of hosts. Nonetheless, this phenomenon is poorly understood due to lack of insights on the coordinated secretome weaponries produced by C. lunatus under heat-stress conditions on putative hosts. To understand the mechanism better, we dissected the secretome of C. lunatus interacting with potato (Solanum tuberosum L.) leaf at different temperature regimes. Results C. lunatus produced melanized colonizing hyphae in and on potato leaf, finely modulated the ambient pH as a function of temperature and secreted diverse set of proteins. Using two dimensional gel electrophoresis (2-D) and mass spectrometry (MS) technology, we observed discrete secretomes at 20°C, 28°C and 38°C. A total of 21 differentially expressed peptide spots and 10 unique peptide spots (that did not align on the gels) matched with 28 unique protein models predicted from C. lunatus m118 v.2 genome peptides. Furthermore, C. lunatus secreted peptides via classical and non-classical pathways related to virulence, proteolysis, nucleic acid metabolism, carbohydrate metabolism, heat stress, signal trafficking and some with unidentified catalytic domains. Conclusions We have identified a set of 5 soluble candidate effectors of unknown function from C. lunatus secretome weaponries against potato crop at different temperature regimes. Our findings demonstrate that C. lunatus has a repertoire of signature secretome which mediates thermo-pathogenicity and share a leucine rich “CL[xxxx]LHM”-motif. Considering the rapidly evolving temperature dependent-virulence and host diversity of C. lunatus, this data will be useful for designing new protection strategies. PMID:24650331

  2. 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

  3. Impacts of wind farms on surface air temperatures.

    PubMed

    Baidya Roy, Somnath; Traiteur, Justin J

    2010-10-19

    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.

  4. Net carbon dioxide exchange rates and predicted growth patterns in Alstroemeria Jacqueline' at varying irradiances, carbon dioxide concentrations, and air temperatures

    SciTech Connect

    Leonardos, E.D.; Tsujita, M.J.; Grodzinski, B. . Dept. of Horticultural Science)

    1994-11-01

    The influence of irradiance, CO[sub 2] concentration, and air temperature on leaf and whole-plant net C exchange rate (NCER) of Alstroemeria Jacqueline' was studied. At ambient CO[sub 2], leaf net photosynthesis was maximum at irradiances above 600 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] photosynthetically active radiation (PAR), while whole-plant NCER required 1,200 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] PAR to be saturated. Leaf and whole-plant NCERs were doubled under CO[sub 2] enrichment of 1,500 to 2,000 [mu]l CO[sub 2]/liter. Leaf and whole-plant NCERs declined as temperature increased from 20 to 35 C. Whereas the optimum temperature range for leaf net photosynthesis was 17 to 23 C, whole-plant NCER, even at high light and high CO[sub 2], declined above 12 C. Dark respiration of leaves and whole plants increased with a Q[sub 10] of [approx] 2 at 15 to 35 C. In an analysis of day effects, irradiance, CO[sub 2] concentration, and temperature contributed 58%, 23%, and 14%, respectively, to the total variation in NCER explained by a second-order polynomial model (R[sup 2] = 0.85). Interactions among the factors accounted for 4% of the variation in day C assimilation. The potential whole-plant growth rates during varying greenhouse day and night temperature regimes were predicted for short- and long-day scenarios. The data are discussed with the view of designing experiments to test the importance of C gain in supporting flowering and high yield during routine harvest of Alstroemeria plants under commercial greenhouse conditions.

  5. The research of air pollution based on spectral features in leaf surface of Ficus microcarpa in Guangzhou, China.

    PubMed

    Wang, Jie; Xu, Ruisong; Ma, Yueliang; Miao, Li; Cai, Rui; Chen, Yu

    2008-07-01

    Nowadays development of industry and traffic are the main contributor to city air pollution in the city of GuangZhou, China. Conventional methods for investigating atmosphere potentially harmful element pollution based on sampling and chemical analysis are time and labor consuming and relatively expensive. Reflectance spectroscopy within the visible-near-infrared region of vegetation in city has been widely used to predict atmosphere constituents due to its rapidity, convenience and accuracy. The objective of this study was to examine the possibility of using leaves reflectance spectra of vegetation as a rapid method to simultaneously assess pollutant (S, Cd, Cu, Hg, Pb, XCl, XF) in the atmosphere of the Guangzhou area. This article has studied the spectral features of polluted leaf surface of Ficus microcarpa in 1985 and 1998. According to the analysis, comprehensive assessment for the change of atmospheric condition and degrees of pollution were given. This conclusion was confirmed by the monitored data got from chemical analysis. Future study with real remote sensing data and field measurements were strongly recommended.

  6. Combustion and gasification characteristics of pulverized coal using high-temperature air

    SciTech Connect

    Hanaoka, R.; Nakamura, M.; Kiga, T.; Kosaka, H.; Iwahashi, T.; Yoshikawa, K.; Sakai, M.; Muramatsu, K.; Mochida, S.

    1998-07-01

    In order to confirm performance of high-temperature-air combusting of pulverized coal, laboratory-scale combustion and gasification tests of coal were conducted changing air temperature and oxygen concentration in the air. Theses were conducted in a drop tube furnace of 200mm in inside diameter and 2,000mm in length. The furnace was heated by ceramic heater up to 1,300 C. A high-temperature air preheater utilizing the HRS (High Cycle Regenerative Combustion System) was used to obtain high-temperature combustion air. As the results, NOx emission was reduced when pulverized coal was fired with high-temperature-air. On the other hand, by lower oxygen concentration in combustion air diluted by nitrogen, NOx emission slightly decreased while became higher under staging condition.

  7. Effect of CO sub 2 enriched air on the kinetics of leaf expansion. [Pisum sativa; Glycine max

    SciTech Connect

    Potter, J.R. )

    1991-05-01

    Vegetative plants of Pisum sativum (pea) and Glycine max (soybean) were transferred from 350 to 1,200 ppm CO{sub 2} when they had one (pea) or two (soybean) mature leaves and several developing leaves. Controls were kept at 350 ppm. For pea, high CO{sub 2} for 8 days increased dry mass of root, stem, and leaf fractions by 30-50%. Leaf dry mass increase was due primarily to carbohydrate, particularly starch. Dawn levels of starch increased 10-fold within 1 day at high CO{sub 2} and 20-fold at 2 days. At 2 days after transfer leaf starch levels were 1.0 mg cm{sup {minus}2} of leaf area or nearly 30% of leaf dry weight. Soybean data are less complete, but 10 days at high CO{sub 2} increased leaf + stem dry mass by 50% and leaf weight per unit area increased by 14 and 48% at dawn within 1 and 2 days, respectively, at high CO{sub 2}. However 8-10 days at high CO{sub 2} increased total leaf area only slightly (about 15%) for both species, with all the leaf area increase occurring at nodes that were nearly microscopic at the time of transfer. For soybean, most of the increased leaf area due to high CO{sub 2} was from lateral bud break despite a high CO{sub 2} did not stimulated more leaves per plant. Apparently, extra photosynthate had a delayed effect on leaf expansion and did not increase nodes along the main axis. Leaf expansion under high CO{sub 2} was not limited by photosynthate.

  8. Experimental study of the decrease in the temperature of an air/water-cooled turbine blade

    NASA Astrophysics Data System (ADS)

    Ryzhov, A. A.; Sereda, A. V.; Shaiakberov, V. F.; Iskakov, K. M.; Shatalov, Iu. S.

    Results of the full-scale testing of an air/water-cooled deflector-type turbine blade are reported. Data on the decrease in the temperature of the cooling air and of the blade are presented and compared with the calculated values. An analysis of the results indicates that the use of air/water cooling makes it possible to significantly reduce the temperature of the cooling air and of the blade with practically no increase in the engine weight and dimensions.

  9. 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.

  10. Environmentally sound thermal energy extraction from coal and wastes using high temperature air combustion technology

    SciTech Connect

    Yoshikawa, Kunio

    1999-07-01

    High temperature air combustion is one of promising ways of burning relatively low BTU gas obtained from gasification of low grade coal or wastes. In this report, the author proposes a new power generation system coupled with high temperature air gasification of coal/wastes and high temperature air combustion of the syngas from coal/wastes. This system is realized by employing Multi-staged Enthalpy Extraction Technology (MEET). The basic idea of the MEET system is that coal or wastes are gasified with high temperature air of about 1,000 C, then the generated syngas is cooled in a heat recovery boiler to be cleaned-up in a gas cleanup system (desulfurization, desalinization and dust removal). Part of thermal energy contained in this cleaned-up syngas is used for high temperature air preheating, and the complete combustion of the fuel gas is done using also high temperature air for driving gas turbines or steam generation in a boiler.

  11. Photosynthetic responses to leaf surface wetness in tropical plant species of Costa Rica with varying leaf traits

    NASA Astrophysics Data System (ADS)

    Aparecido, L. M. T.; Moore, G. W.; Miller, G. R.; Cahill, A. T.

    2015-12-01

    Wet tropical forests are some of the environments with the greatest annual precipitation, but are also considered as the world's major carbon sink; however, literature postulates that phothsynthesis rates are inhibited while leaves are wet. Yet measurements of photosynthesis during wet conditions are challenging to obtain due to equipment limitations and the extreme complexity of canopy-atmosphere interactions in tropical environments. The objective of this study was to evaluate tropical species reactions to simulated leaf wetness and test the hypothesis that leaf wetness reduces rates of photosynthesis. In a central Costa Rica site with an average 4200 mm annual rainfall, we selected six tropical species with distinct leaf traits in which five sun-exposed leaf replicates from each species were subjected to gas exchange measurements using a LI-6400 IRGA (LICOR Inc., Lincoln, NE) under dry and wet/misted leaf conditions. Relationships between photosynthesis (As) and stomatal conductance (gs) with leaf to air temperature difference (DT), VPD, and relative humidity were evaluated using linear regression analysis. We found that the responses varied greatly among species, but all plants maintained a baseline of activity under wet leaf conditions, suggesting that abaxial leaf As was a significant percentage of total leaf As. Stachytarpheta jamaicens had an 18.7% reduction in As, while others, like Zamia skinneri, had a 7% increase in As. Tibouchina heteromalla showed a rapid stomatal recovery of 2 mins, while Carapa guianensis was slower with 7 mins. This variability between species suggests that leaf traits, such as presence or absence of trichomes, water repellency, vein distribution and size and leaf angle variation, may be critical for optimizing photosynthesis under wet conditions. Relative humidity and leaf temperature were the strongest secondary influences on As and gs under wet leaf conditions. While tropical vegetation-atmosphere interactions are complex, such

  12. Temporal and spatial assessments of minimum air temperature using satellite surface temperature measurements in Massachusetts, USA

    PubMed Central

    Kloog, Itai; Chudnovsky, Alexandra; Koutrakis, Petros; Schwartz, Joel

    2015-01-01

    Although meteorological stations provide accurate air temperature observations, their spatial coverage is limited and thus often insufficient for epidemiological studies. Satellite data expand spatial coverage, enhancing our ability to estimate near surface air temperature (Ta). However, the derivation of Ta from surface temperature (Ts) measured by satellites is far from being straightforward. In this study, we present a novel approach that incorporates land use regression, meteorological variables and spatial smoothing to first calibrate between Ts and Ta on a daily basis and then predict Ta for days when satellite Ts data were not available. We applied mixed regression models with daily random slopes to calibrate Moderate Resolution Imaging Spectroradiometer (MODIS) Ts data with monitored Ta measurements for 2003. Then, we used a generalized additive mixed model with spatial smoothing to estimate Ta in days with missing Ts. Out-of-sample tenfold cross-validation was used to quantify the accuracy of our predictions. Our model performance was excellent for both days with available Ts and days without Ts observations (mean out-of-sample R2=0.946 and R2=0.941 respectively). Furthermore, based on the high quality predictions we investigated the spatial patterns of Ta within the study domain as they relate to urban vs. non-urban land uses. PMID:22721687

  13. Temporal and spatial assessments of minimum air temperature using satellite surface temperature measurements in Massachusetts, USA.

    PubMed

    Kloog, Itai; Chudnovsky, Alexandra; Koutrakis, Petros; Schwartz, Joel

    2012-08-15

    Although meteorological stations provide accurate air temperature observations, their spatial coverage is limited and thus often insufficient for epidemiological studies. Satellite data expand spatial coverage, enhancing our ability to estimate near surface air temperature (Ta). However, the derivation of Ta from surface temperature (Ts) measured by satellites is far from being straightforward. In this study, we present a novel approach that incorporates land use regression, meteorological variables and spatial smoothing to first calibrate between Ts and Ta on a daily basis and then predict Ta for days when satellite Ts data were not available. We applied mixed regression models with daily random slopes to calibrate Moderate Resolution Imaging Spectroradiometer (MODIS) Ts data with monitored Ta measurements for 2003. Then, we used a generalized additive mixed model with spatial smoothing to estimate Ta in days with missing Ts. Out-of-sample tenfold cross-validation was used to quantify the accuracy of our predictions. Our model performance was excellent for both days with available Ts and days without Ts observations (mean out-of-sample R(2)=0.946 and R(2)=0.941 respectively). Furthermore, based on the high quality predictions we investigated the spatial patterns of Ta within the study domain as they relate to urban vs. non-urban land uses.

  14. Simultaneous Measurement of Air Temperature and Humidity Based on Sound Velocity and Attenuation Using Ultrasonic Probe

    NASA Astrophysics Data System (ADS)

    Motegi, Takahiro; Mizutani, Koichi; Wakatsuki, Naoto

    2013-07-01

    In this paper, an acoustic technique for air temperature and humidity measurement in moist air is described. The previous ultrasonic probe can enable the estimation of temperature from sound velocity in dry air by making use of the relationship between sound velocity and temperature. However, temperature measurement using the previous ultrasonic probe is not suitable in moist air because sound velocity also depends on humidity, and the temperature estimated from the sound velocity measured in moist air must be adjusted. Moreover, a method of humidity measurement by using only an ultrasonic probe has not been established. Thus, we focus on sound attenuation, which depends on temperature and humidity. Our proposed technique utilizes two parameters, sound velocity and attenuation, and can measure both temperature and humidity simultaneously. The acoustic technique for temperature and humidity measurement has the advantages that instantaneous temperature and humidity can be measured, and the measurement is not affected by thermal radiation because air itself is used as a sensing element. As an experiment, temperature and humidity are measured in a chamber, and compared with the reference values. The experimental results indicate the achievement of a practical temperature measurement accuracy of within +/-0.5 K in moist air, of which the temperature is 293-308 K and relative humidity (RH) is 50-90% RH, and the simultaneous measurement of temperature and humidity.

  15. Metaproteome analysis of the microbial community during leaf litter decomposition - the impact of stoichiometry and temperature perturbations

    NASA Astrophysics Data System (ADS)

    Keiblinger, K. M.; Schneider, T.; Leitner, S.; Hämmerle, I.; Riedel, K.; Zechmeister-Boltenstern, S.

    2012-04-01

    Leaf litter decomposition is the breakdown of dead plant material, a terrestrial ecosystem process of paramount importance. Nutrients released during decomposition play a key role for microbial growth and plant productivity. These processes are controlled by abiotic factors, such as climate, and by biotic factors, such as litter nutrient concentration and stoichiometry (carbon:nutrient ratio) and activity of soil organisms. Future climate change scenarios predict temperature perturbations, therefore following changes of microbial community composition and possible feedbacks on ecosystem processes are of key interest; especially as our knowledge about the microbial regulation of these processes is still scarce. Our aim was to elucidate how temperature perturbations and leaf litter stoichiometry affect the composition of the microbial decomposer community. To this end a terrestrial microcosm experiment using beech (Fagus sylvatica) litter with different stoichiometry was conducted. In a semi-quantitative metaproteomics approach (1D-SDS PAGE combined with liquid chromatography and tandem mass spectrometry; unique spectral counting) we used the intrinsic metabolic function of proteins to relate specific microbial activities to their phylogenetic origin in multispecies communities. Decomposer communities varied on litter with different stoichiometry so that microbial decomposers (fungi and bacteria) were favoured in litter with narrow C:nutrient ratios. The fungal community was dominated by Ascomycota (Eurotiomycetes, Sordariomycetes) and Basidiomycota (Agaricomycetes) and the bacterial community was dominated by Proteobacteria, Actinobacteria and Firmicutes. The extracellular enzymes we detected belonged mainly to classes of xylanases, pectinases, cellulases and proteases and were almost exclusively of fungal origin (particularly Ascomycota). Temperature stress (heat and frost) evoked strong changes in community composition, enzyme activities, dissolved organic

  16. Compression-ignition Engine Performance at Altitudes and at Various Air Pressures and Temperatures

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H

    1937-01-01

    Engine test results are presented for simulated altitude conditions. A displaced-piston combustion chamber on a 5- by 7-inch single cylinder compression-ignition engine operating at 2,000 r.p.m. was used. Inlet air temperature equivalent to standard altitudes up to 14,000 feet were obtained. Comparison between performance at altitude of the unsupercharged compression-ignition engine compared favorably with the carburetor engine. Analysis of the results for which the inlet air temperature, inlet air pressure, and inlet and exhaust pressure were varied indicates that engine performance cannot be reliably corrected on the basis of inlet air density or weight of air charge. Engine power increases with inlet air pressure and decreases with inlet air temperatures very nearly as straight line relations over a wide range of air-fuel ratios. Correction factors are given.

  17. Direct and indirect toxicity of the fungicide pyraclostrobin to Hyalella azteca and effects on leaf processing under realistic daily temperature regimes.

    PubMed

    Willming, Morgan M; Maul, Jonathan D

    2016-04-01

    Fungicides in aquatic environments can impact non-target bacterial and fungal communities and the invertebrate detritivores responsible for the decomposition of allochthonous organic matter. Additionally, in some aquatic systems daily water temperature fluctuations may influence these processes and alter contaminant toxicity, but such temperature fluctuations are rarely examined in conjunction with contaminants. In this study, the shredding amphipod Hyalella azteca was exposed to the fungicide pyraclostrobin in three experiments. Endpoints included mortality, organism growth, and leaf processing. One experiment was conducted at a constant temperature (23 °C), a fluctuating temperature regime (18-25 °C) based on field-collected data from the S. Llano River, Texas, or an adjusted fluctuating temperature regime (20-26 °C) based on possible climate change predictions. Pyraclostrobin significantly reduced leaf shredding and increased H. azteca mortality at concentrations of 40 μg/L or greater at a constant 23 °C and decreased leaf shredding at concentrations of 15 μg/L or greater in the fluctuating temperatures. There was a significant interaction between temperature treatment and pyraclostrobin concentration on H. azteca mortality, body length, and dry mass under direct aqueous exposure conditions. In an indirect exposure scenario in which only leaf material was exposed to pyraclostrobin, H. azteca did not preferentially feed on or avoid treated leaf disks compared to controls. This study describes the influence of realistic temperature variation on fungicide toxicity to shredding invertebrates, which is important for understanding how future alterations in daily temperature regimes due to climate change may influence the assessment of ecological risk of contaminants in aquatic ecosystems.

  18. Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations

    PubMed Central

    Narayanan, Sruthi; Tamura, Pamela J.; Roth, Mary R.; Vara Prasad, P.V.; Welti, Ruth

    2016-01-01

    Understanding how wheat (Triticum aestivum L.) plants under high temperature (HT) regulate lipid composition is critical to developing climate-resilient varieties. We measured 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat leaves using electrospray ionization-tandem mass spectrometry. Levels of polar lipid fatty acyl chain unsaturation were lower in both heat-tolerant genotype Ventnor and susceptible genotype Karl 92 under HT, compared to optimum temperature. The lower unsaturation was predominantly due to lower levels of 18:3 and higher levels of 18:1 and 16:0 acyl chains. Levels of 18:3-containing triacylglycerols increased 3-fold/more under HT, consistent with their possible role in sequestering fatty acids during membrane lipid remodeling. Phospholipids containing odd-numbered or oxidized acyl chains accumulated in leaves under HT. Sterol glycosides (SG) and 16:0-acylated sterol glycosides (ASG) were higher under HT than optimum temperatures. Ventnor had lower amounts of phospholipids with oxidized acyl chains under HT and higher amounts of SG and 16:0-ASG than Karl 92. Taken together, the data demonstrate that wheat leaf lipid composition is altered by HT, that some lipids are particularly responsive to HT, and that two wheat genotypes, chosen for their differing physiological responses to HT, differ in lipid profile under HT. PMID:26436679

  19. Ozone air pollution effects on tree-ring growth, delta(13)C, visible foliar injury and leaf gas exchange in three ozone-sensitive woody plant species.

    PubMed

    Novak, Kristopher; Cherubini, Paolo; Saurer, Matthias; Fuhrer, Jürg; Skelly, John M; Kräuchi, Norbert; Schaub, Marcus

    2007-07-01

    We assessed the effects of ambient tropospheric ozone on annual tree-ring growth, delta(13)C in the rings, leaf gas exchange and visible injury in three ozone-sensitive woody plant species in southern Switzerland. Seedlings of Populus nigra L., Viburnum lantana L. and Fraxinus excelsior L. were exposed to charcoal-filtered air (CF) and non-filtered air (NF) in open-top chambers, and to ambient air (AA) in open plots during the 2001 and 2002 growing seasons. Ambient ozone exposures in the region were sufficient to cause visible foliar injury, early leaf senescence and premature leaf loss in all species. Ozone had significant negative effects on net photosynthesis and stomatal conductance in all species in 2002 and in V. lantana and F. excelsior in 2001. Water-use efficiency decreased and intercellular CO(2) concentrations increased in all species in response to ozone in 2002 only. The width and delta(13)C of the 2001 and 2002 growth rings were measured for all species at the end of the 2002 growing season. Compared with CF seedlings, mean ring width in the AA and NF P. nigra seedlings was reduced by 52 and 46%, respectively, in 2002, whereas in V. lantana and F. excelsior, ring width showed no significant reductions in either year. Although delta(13)C was usually more negative in CF seedlings than in AA and NF seedlings, with the exception of F. excelsior in 2001, ozone effects on delta(13)C were significant only for V. lantana and P. nigra in 2001. Among species, P. nigra exhibited the greatest response to ozone for the measured parameters as well as the most severe foliar injury and was the only species to show a significant reduction in ring width in response to ozone exposure, despite significant negative ozone effects on leaf gas exchange and the development of visible foliar injury in V. lantana and F. excelsior. Thus, significant ozone-induced effects at the leaf level did not correspond to reduced tree-ring growth or increased delta(13)C in all species

  20. Short-term effects of air temperature on plasma metabolite concentrations in patients undergoing cardiac cattheterization.

    EPA Science Inventory

    BACKGROUND: Epidemiological studies have shown associations between air temperature and cardiovascular health outcomes. Metabolic dysregulation might also play a role in the development of cardiovascular disease.OBJECTIVES: To investigate short-term temperature effects on metabol...

  1. Rainfall Prediction using Soil and Air Temperature in a Tropical Station

    NASA Astrophysics Data System (ADS)

    Chacko, Tessy P.; Renuka, G.

    2007-07-01

    An attempt is made to establish a linkage between soil and air temperature and south-west monsoon rainfall at Pillicode (12°12'N,75°10'E) a tropical station in north Kerala. The dependence of monsoon rainfall on pre-monsoon soil temperature decreases as the depth of the soil increases. A regression equation has been developed for the estimation of monsoon rainfall using pre-monsoon soil and air temperature. The results show that sub soil temperature along with air temperature can be used for forecasting the monsoon level.

  2. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 34 2013-07-01 2013-07-01 false NOX intake-air humidity...

  3. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 32 2010-07-01 2010-07-01 false NOX intake-air humidity...

  4. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 33 2014-07-01 2014-07-01 false NOX intake-air humidity...

  5. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 33 2011-07-01 2011-07-01 false NOX intake-air humidity...

  6. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 34 2012-07-01 2012-07-01 false NOX intake-air humidity...

  7. One-Component Pressure-Temperature Phase Diagrams in the Presence of Air

    ERIC Educational Resources Information Center

    Andrade-Gamboa, Julio; Martire, Daniel O.; Donati, Edgardo R.

    2010-01-01

    One-component phase diagrams are good approximations to predict pressure-temperature ("P-T") behavior of a substance in the presence of air, provided air pressure is not much higher than the vapor pressure. However, at any air pressure, and from the conceptual point of view, the use of a traditional "P-T" phase diagram is not strictly correct. In…

  8. Ideas and perspectives: Heat stress: more than hot air

    NASA Astrophysics Data System (ADS)

    De Boeck, Hans J.; Van De Velde, Helena; De Groote, Toon; Nijs, Ivan

    2016-10-01

    Climate models project an important increase in the frequency and intensity of heat waves. In gauging the impact on plant responses, much of the focus has been on air temperatures, while a critical analysis of leaf temperatures during heat extremes has not been conducted. Nevertheless, direct physiological consequences from heat depend primarily on leaf rather than on air temperatures. We discuss how the interplay between various environmental variables and the plants' stomatal response affects leaf temperatures and the potential for heat stress by making use of both an energy balance model and field data. The results demonstrate that this interplay between plants and environment can cause leaf temperature to vary substantially at the same air temperature. In general, leaves tended to heat up when radiation was high and when stomates were closed, as expected. But perhaps counterintuitively, high air humidity also raised leaf temperatures, while humid conditions are typically regarded as benign with respect to plant survival since they limit water loss. High wind speeds brought the leaf temperature closer to the air temperature, which can imply either cooling or warming (i.e. abating or reinforcing heat stress) depending on other prevailing conditions. The results thus indicate that heat waves characterized by similar extreme air temperatures may pose little danger under some atmospheric conditions but could be lethal in other cases. The trends illustrated here should give ecologists and agronomists a more informed indication about which circumstances are most conducive to the occurrence of heat stress.

  9. Changes during leaf expansion of ΦPSII temperature optima in Gossypium hirsutum are associated with the degree of fatty acid lipid saturation.

    PubMed

    Hall, Trent D; Chastain, Daryl R; Horn, Patrick J; Chapman, Kent D; Choinski, John S

    2014-03-15

    In this project, we hypothesize that cotton (Gossypium hirsutum) leaf temperature and the responses of leaf photosynthesis to temperature will change as the leaves expand and that differences between young and mature leaves will be associated with the proportion of saturated fatty acids in thylakoid and other membrane lipids. To that end, we studied main stem leaves obtained from plants growing in a temperature controlled greenhouse and at different times in the field season. We found that young leaves (∼5d old) had higher mid day temperatures, lower stomatal conductance and higher thermal optima as measured by ΦPSII temperature curves than did more mature leaves (∼13d old). Young leaves also had significant differences in fatty acid saturation with the warmer, young leaves having a higher proportion of palmitic acid (16:0) and lower linoleic acid (18:3) in total lipid extracts and higher 16:0 and lower palmitoleic acid (16:1) in the chloroplast membrane phosphoglycerides, digalactosyldiacylglycerol (in the greenhouse) and phosphatidylglycerol when compared with cooler, more mature leaves. Later in the growing season, leaf temperature, stomatal conductance and ΦPSII temperature curves for young and more mature leaves were similar and the proportion of 16:0 fatty acids decreased and 16:1 increased in phosphatidylglycerol. We conclude that changes in temperature as cotton leaves expand leads to alterations in the fatty acid composition of thylakoid and other membranes and, consequently, influence photosynthesis/temperature responses.

  10. Leaf and canopy responses to elevated CO{sub 2} in a pine plantation under free-air CO{sub 2} enrichment (FACE)

    SciTech Connect

    Ellsworth, D.S.; Oren, R.; Hendrey, G. |

    1995-09-01

    Free-air CO{sub 2} enrichment (FACE) was used to expose an intact lobolly pine forest ecosystem to elevated CO{sub 2}. Leaf conductance and canopy water flux measurements along with A{sub net}-C{sub i} curves were used to evaluate physiological responses of the dominant trees to elevated CO{sub 2}. CO{sub 2}-exposed trees showed minor (<7%) but significant reductions in sap flux density compared to trees under ambient CO{sub 2} conditions, but only when air saturation vapor pressure deficit (VPD) was low. Short-term (minutes) direct stomatal responses to elevated CO{sub 2} were also relatively weak. We observed no evidence of adjustments in stomatal conductance in current-year foliage grown under elevated CO{sub 2} for 80 days compared to foliage grown under ambient CO{sub 2}. Leaf net photosynthetic rate at 550 {mu}mol mol{sup {minus}1} CO{sub 2} was enhanced by more than 50% compared to the rate at ambient CO{sub 2}(350 {mu}mol mol{sup {minus}1}). Thus, leaf water-use-efficiency of loblolly pine at elevated CO{sub 2} was enhanced primarily by direct responses of photosynthesis to CO{sub 2} and was not mediated by stomata.

  11. Effects of Mild Water Stress and Diurnal Changes in Temperature and Humidity on the Stable Oxygen and Hydrogen Isotopic Composition of Leaf Water in Cornus stolonifera L. 1

    PubMed Central

    Flanagan, Lawrence B.; Ehleringer, James R.

    1991-01-01

    In this paper we make comparisons between the observed stable isotopic composition of leaf water and the predictions of the Craig-Gordon model of isotopic enrichment when plants (Cornus stolonifera L.) were exposed to natural, diurnal changes in temperature and humidity in a glasshouse. In addition, we determined the effects of mild water stress on the isotopic composition of leaf water. The model predicted different patterns of diurnal change for the oxygen and hydrogen isotopic composition of leaf water. The observed leaf water isotopic composition followed qualitatively similar patterns of diurnal change to those predicted by the model. At midday, however, the model always predicted a higher degree of heavy isotope enrichment than was actually observed in leaves. There was no effect of mild water stress on the hydrogen isotopic composition of leaf water. For the oxygen isotopic composition of leaf water, there was either no significant difference between control and water-stressed plants or the stressed plants had lower δ18O values, despite the enriched stem water isotopic composition observed for the stressed plants. PMID:16668385

  12. Startup of air-cooled condensers and dry cooling towers at low temperatures of the cooling air

    NASA Astrophysics Data System (ADS)

    Milman, O. O.; Ptakhin, A. V.; Kondratev, A. V.; Shifrin, B. A.; Yankov, G. G.

    2016-05-01

    The problems of startup and performance of air-cooled condensers (ACC) and dry cooling towers (DCT) at low cooling air temperatures are considered. Effects of the startup of the ACC at sub-zero temperatures are described. Different options of the ACC heating up are analyzed, and examples of existing technologies are presented (electric heating, heating up with hot air or steam, and internal and external heating). The use of additional heat exchanging sections, steam tracers, in the DCT design is described. The need for high power in cases of electric heating and heating up with hot air is noted. An experimental stand for research and testing of the ACC startup at low temperatures is described. The design of the three-pass ACC unit is given, and its advantages over classical single-pass design at low temperatures are listed. The formation of ice plugs inside the heat exchanging tubes during the start-up of ACC and DCT at low cooling air temperatures is analyzed. Experimental data on the effect of the steam flow rate, steam nozzle distance from the heat-exchange surface, and their orientation in space on the metal temperature were collected, and test results are analyzed. It is noted that the surface temperature at the end of the heat up is almost independent from its initial temperature. Recommendations for the safe start-up of ACCs and DCTs are given. The heating flow necessary to sufficiently heat up heat-exchange surfaces of ACCs and DCTs for the safe startup is estimated. The technology and the process of the heat up of the ACC with the heating steam external supply are described by the example of the startup of the full-scale section of the ACC at sub-zero temperatures of the cooling air, and the advantages of the proposed start-up technology are confirmed.

  13. Temperature and substrate chemistry as major drivers of interregional variability of leaf microbial decomposition and cellulolytic activity in headwater streams.

    PubMed

    Fenoy, Encarnación; Casas, J Jesús; Díaz-López, Manuel; Rubio, Juan; Guil-Guerrero, J Luís; Moyano-López, Francisco J

    2016-11-01

    Abiotic factors, substrate chemistry and decomposers community composition are primary drivers of leaf litter decomposition. In soil, much of the variation in litter decomposition is explained by climate and substrate chemistry, but with a significant contribution of the specialisation of decomposer communities to degrade specific substrates (home-field advantage, HFA). In streams, however, HFA effects on litter decomposition have not been explicitly tested. We evaluated responses of microbial decomposition and β-glucosidase activity to abiotic factors, substrate and decomposer assemblages, using a reciprocal litter transplant experiment: 'ecosystem type' (mountain vs lowland streams) × 'litter chemistry' (alder vs reed). Temperature, pH and ionic concentration were higher in lowland streams. Decomposition for both species was faster in lowland streams. Decomposition of reed was more accelerated in lowland compared with mountain streams than that of alder, suggesting higher temperature sensitivity of decomposition in reed. Q10 (5°C-15°C) values of β-glucosidase activity were over 2. The alkaline pH and high ionic concentration of lowland streams depleted enzyme activity. We found similar relationships of decomposition or enzyme activity with abiotic factors for both species, suggesting limited support to the HFA hypothesis. Overall, our results suggest a prime role of temperature interacting with substrate chemistry on litter decomposition.

  14. Effect of altering the root-zone temperature on growth, translocation, carbon exchange rate, and leaf starch accumulation in the tomato.

    PubMed

    Hurewitz, J; Janes, H W

    1983-09-01

    Tomato seedlings (Lycopersicon esculentum Mill. cv Vendor) were grown hydroponically with their root systems maintained at a constant temperature for a 2-week period commencing with the appearance of the first true leaf. Based on fresh and dry weight and leaf area, the optimal root-zone temperature for seedling growth was 30 degrees C. The carbon exchange rate of the leaves was also found to increase with rising root-zone temperature up to 30 degrees C. However, a more complex relationship seems to exist between root-zone temperature and the accumulation of (14)C-labeled assimilates in the roots; inasmuch as there is no enhancement in this accumulation at the most growth promoting root-zone temperatures (22-30 degrees C).

  15. Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

  16. Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

    1939-01-01

    Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

  17. Predicting seed cotton moisture content from changes in drying air temperature - second year

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mathematical model was used to predict seed cotton moisture content in the overhead section of a cotton gin. The model took into account the temperature, mass flow, and specific heat of both the air and seed cotton. Air temperatures and mass flows were measured for a second year at a commercial g...

  18. Prediction of air temperature in the aircraft cabin under different operational conditions

    NASA Astrophysics Data System (ADS)

    Volavý, F.; Fišer, J.; Nöske, I.

    2013-04-01

    This paper deals with the prediction of the air temperature in the aircraft cabin by means of Computational Fluid Dynamics. The simulations are performed on the CFD model which is based on geometry and cabin interior arrangement of the Flight Test Facility (FTF) located at Fraunhofer IBP, Germany. The experimental test flights under three different cabin temperatures were done in FTF and the various data were gathered during these flights. Air temperature in the cabin was measured on probes located near feet, torso and head of each passenger and also surface temperature and air temperature distributed from inlets were measured. The data were firstly analysed in order to obtain boundary conditions for cabin surfaces and inlets. Then the results of air temperature from the simulations were compared with measured data. The suitability and accuracy of the CFD approach for temperature prediction is discussed.

  19. System and method for air temperature control in an oxygen transport membrane based reactor

    DOEpatents

    Kelly, Sean M

    2016-09-27

    A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  20. Air temperature "singularities" as a tool for the comprehension of the climate diversity in Europe

    NASA Astrophysics Data System (ADS)

    Jarzyna, Krzysztof

    2014-05-01

    Air temperature "singularities" were used to study climate diversity in Europe. The basis of analysis were data of mean daily air temperature for 50-years period (1951-2000) from 66 European meteorological stations. Multiyear mean air temperature values were counted for the each day of the year at first (29th February was omitted). Next a theoretical sine curve of annual air temperature course was created with help of the Fourier's analysis for the each station. Differences between theoretical and observed mean vales of daily air temperatures were counted in the next step. The biggest of these differences (below the lower quartile and above the upper quartile) lasting at least 3 days can be treated as thermal "singularities". A cluster analysis was used to find similarities of the singularities occurrence in analyzed stations. As a result 8 clusters were distinguished representing regions with different thermal "singularities" occurrence pattern.

  1. Modeling subcanopy incoming longwave radiation to seasonal snow using air and tree trunk temperatures

    NASA Astrophysics Data System (ADS)

    Webster, Clare; Rutter, Nick; Zahner, Franziska; Jonas, Tobias

    2016-02-01

    Data collected at three Swiss alpine forested sites over a combined 11 year period were used to evaluate the role of air temperature in modeling subcanopy incoming longwave radiation to the snow surface. Simulated subcanopy incoming longwave radiation is traditionally partitioned into that from the sky and that from the canopy, i.e., a two-part model. Initial uncertainties in predicting longwave radiation using the two-part model resulted from vertical differences in measured air temperature. Above-canopy (35 m) air temperatures were higher than those within (10 m) and below (2 m) canopy throughout four snow seasons (December-April), demonstrating how the forest canopy can act as a cold sink for air. Lowest model root-mean-square error (RMSE) was using above-canopy air temperature. Further investigation of modeling subcanopy longwave radiation using above-canopy air temperature showed underestimations, particularly during periods of high insolation. In order to explicitly account for canopy temperatures in modeling longwave radiation, the two-part model was improved by incorporating a measured trunk view component and trunk temperature. Trunk temperature measurements were up to 25°C higher than locally measured air temperatures. This three-part model reduced the RMSE by up to 7.7 W m-2 from the two-part air temperature model at all sensor positions across the 2014 snowmelt season and performed particularly well during periods of high insolation when errors from the two-part model were up to 40 W m-2. A parameterization predicting tree trunk temperatures using measured air temperature and incoming shortwave radiation demonstrate a simple method that can be applied to provide input to the three-part model across midlatitude coniferous forests.

  2. Impact of Surface Air Temperature and Snow Cover Depth on the Upper Soil Temperature Variations in Russia

    NASA Astrophysics Data System (ADS)

    Sherstyukov, A. B.; Sherstyukov, B. G.; Groisman, P. Y.

    2007-12-01

    A study of the impact of climate changes during for the last four decades on soil temperatures at depths up to 3.2 meters has been conducted for the territory of Russia. For the 1965-2004 period, we compiled and analyzed data from all Russian meteorological stations with long-term soil temperature observations at depths 80, 160 and 320 cm. Traditionally, these stations also observe a complete set of standard meteorological variables (that include surface air temperature and extensive monitoring of snow cover characteristics). This allowed us to investigate the impact of surface air temperatures and snow depth variations on soil temperatures in the upper soil layer, to quantify it using statistical analyses of multi-dimensional 40-year-long time series at 164 locations throughout the country, and assess the representativeness of the obtained results. Three-dimensional spatial distributions of regression and correlation coefficients were mapped for warm and cold seasons separately as well as for the entire year, and thereafter analyzed. In the permafrost zone we found special features in these fields that distinctively separate the permafrost zone from the remaining territory. In this zone, soil temperatures are practically uncorrelated with surface air temperatures and variations of the snow depth controls soil temperature variations (with R2 up to 0.5) Quantitative estimates of the contribution of mid-annual air temperature and snow cover depth in the long-term changes of mid-annual soil temperatures across the Russia territory were received. We found that the prevailing influence on soil temperature variations in the European part was surface air temperatures and in the Asian part of Russia was snow cover depth. Furthermore, increase of the winter snow depth in the permafrost zone (by preserving the heat accumulated in the warm season) promotes annual soil temperature increase and therefore may foster the further permafrost degradation associated with ongoing

  3. 1-methylcyclopropene (1-MCP)-induced alteration in leaf photosynthetic rate, chlorophyll fluorescence, respiration and membrane damage in rice (Oryza sativa L.) under high night temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High night temperature (HNT) can induce ethylene-triggered reactive oxygen species production, which can cause premature leaf senescence and membrane damage, thereby affecting production, consumption and transfer of photosynthates, and yield. The 1-methylcyclopropene (1-MCP) can competitively bind w...

  4. Low-temperature phase behaviour of the major plant leaf lipid monogalactosyldiacylglycerol.

    PubMed

    Sanderson, P W; Williams, W P

    1992-06-11

    Heating and cooling thermograms of unsaturated MGDG samples isolated from the leaves of Vicia faba are surprisingly featureless. This reflects the low enthalpies associated with phase transitions in highly unsaturated lipids and the fact that these transitions, in the case of MGDG, are to a large extent masked by those associated with the freezing and melting of ice. Careful choice of thermal heating/cooling regimes, combined with the use of real-time X-ray diffraction and freeze-fracture measurements, permits a detailed analysis of the phase behaviour of the system. The phase behaviour of unsaturated MGDG samples is shown to be basically similar to that seen in saturated MGDG samples. The lipid which exists in the inverted hexagonal (HexII) liquid crystal phase at room temperature forms a highly disordered lamellar gel (L beta) phase on cooling to temperatures below about -15 degrees C. On reheating, this first reorganizes at a temperature of about -10 degrees C to form a well-defined Lc1 phase. Above about -2 degrees C, this melts to re-form the HexII phase. Samples re-cooled from temperatures between -2 degrees C and 14 degrees C revert directly to the Lc1 phase while samples cooled from higher temperatures form the L beta phase. This reflects the fact that the former samples contain small amounts of unmelted Lc1 phase lipid. The implications of these observations are discussed in terms of the general problems associated with the measurement of low-temperature phase behaviour of membrane lipids.

  5. 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.

  6. 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.

  7. Temperature and evaporative water loss of leaf-sitting frogs: the role of reflection spectra

    PubMed Central

    Blount, Chris; Dickinson, Mark

    2016-01-01

    ABSTRACT The near infrared reflection peak in some frogs has been speculated to be either for enhancing crypticity, or to help them with thermoregulation. The theoretical background for the thermoregulatory processes has been established before, but little consideration has been given to the contribution from the frogs' reflection spectra differences. In this investigation, the reflection spectra from a range of different species of frogs were taken and combined with precise surface area measurements of frogs and an approximation to the mass transfer coefficient of agar frog models. These were then used to simulate the temperature and water evaporation in anurans with and without the near infrared reflective peak. We have shown that the presence of the near infrared reflection peak can contribute significantly to the temperature and evaporative water loss of a frog. The significance of the steady-state temperature differences between frogs with and without the near infrared reflection peak is discussed in a realistic and an extreme scenario. Temperature differences of up to 3.2°C were found, and the rehydration period was increased by up to 16.7%, although this does not reduce the number of rehydration events between dawn and dusk. PMID:27793832

  8. Temperature and evaporative water loss of leaf-sitting frogs: the role of reflection spectra.

    PubMed

    Herrerías-Azcué, Francisco; Blount, Chris; Dickinson, Mark

    2016-12-15

    The near infrared reflection peak in some frogs has been speculated to be either for enhancing crypticity, or to help them with thermoregulation. The theoretical background for the thermoregulatory processes has been established before, but little consideration has been given to the contribution from the frogs' reflection spectra differences. In this investigation, the reflection spectra from a range of different species of frogs were taken and combined with precise surface area measurements of frogs and an approximation to the mass transfer coefficient of agar frog models. These were then used to simulate the temperature and water evaporation in anurans with and without the near infrared reflective peak. We have shown that the presence of the near infrared reflection peak can contribute significantly to the temperature and evaporative water loss of a frog. The significance of the steady-state temperature differences between frogs with and without the near infrared reflection peak is discussed in a realistic and an extreme scenario. Temperature differences of up to 3.2°C were found, and the rehydration period was increased by up to 16.7%, although this does not reduce the number of rehydration events between dawn and dusk.

  9. Seasonal fluctuations and temperature dependence of leaf gas exchange parameters of co-occurring evergreen and deciduous trees in a temperate broad-leaved forest.

    PubMed

    Kosugi, Yoshiko; Matsuo, Naoko

    2006-09-01

    Seasonal fluctuations in leaf gas exchange parameters were investigated in three evergreen (Quercus glauca Thunb., Cinnamomum camphora Sieb. and Castanopsis cuspidata Schottky) and one deciduous (Quercus serrata Thunb.) co-occurring, dominant tree species in a temperate broad-leaved forest. Dark respiration rate (Rn), maximum carboxylation rate (Vcmax) and stomatal coefficient (m), the ratio of stomatal conductance to net assimilation rate after adjustment to the vapor pressure deficit and internal carbon dioxide (CO2) concentration, were derived inversely from instantaneous field gas exchange data (one-point method). The normalized values of Rn and Vcmax at the reference temperature of 25 degrees C (Rn25, Vcmax25) and their temperature dependencies (Delta Ha(Rn), Delta Ha(Vcmax)) were analyzed. Parameter Vcmax25 ranged from 24.0-40.3 micromol m(-2) s(-1) and Delta Ha(Vcmax) ranged from 29.1- 67.0 kJ mol(-1). Parameter Rn25 ranged from 0.6-1.4 micromol m(-2) s(-1) and Delta Ha(Rn) ranged from 47.4-95.4 kJ mol(-1). The stomatal coefficient ranged from 7.2-8.2. For the three evergreen trees, a single set of Vcmax25 and Rn25 parameters and temperature dependence curves produced satisfactory estimates of carbon uptake throughout the year, except during the period of simultaneous leaf fall and leaf expansion, which occurs in April and May. In the deciduous oak, declines in Vcmax25 were observed after summer, along with changes in Vcmax25 and Rn25 during the leaf expansion period. In all species, variation in m during periods of leaf expansion and drought should be considered in modeling studies. We conclude that the changes in normalized gas exchange parameters during periods of leaf expansion and drought need to be considered when modeling carbon uptake of evergreen broad-leaved species.

  10. Considerations for Assessing Maximum Critical Temperatures in Small Ectothermic Animals: Insights from Leaf-Cutting Ants

    PubMed Central

    Ribeiro, Pedro Leite; Camacho, Agustín; Navas, Carlos Arturo

    2012-01-01

    The thermal limits of individual animals were originally proposed as a link between animal physiology and thermal ecology. Although this link is valid in theory, the evaluation of physiological tolerances involves some problems that are the focus of this study. One rationale was that heating rates shall influence upper critical limits, so that ecological thermal limits need to consider experimental heating rates. In addition, if thermal limits are not surpassed in experiments, subsequent tests of the same individual should yield similar results or produce evidence of hardening. Finally, several non-controlled variables such as time under experimental conditions and procedures may affect results. To analyze these issues we conducted an integrative study of upper critical temperatures in a single species, the ant Atta sexdens rubropiosa, an animal model providing large numbers of individuals of diverse sizes but similar genetic makeup. Our specific aims were to test the 1) influence of heating rates in the experimental evaluation of upper critical temperature, 2) assumptions of absence of physical damage and reproducibility, and 3) sources of variance often overlooked in the thermal-limits literature; and 4) to introduce some experimental approaches that may help researchers to separate physiological and methodological issues. The upper thermal limits were influenced by both heating rates and body mass. In the latter case, the effect was physiological rather than methodological. The critical temperature decreased during subsequent tests performed on the same individual ants, even one week after the initial test. Accordingly, upper thermal limits may have been overestimated by our (and typical) protocols. Heating rates, body mass, procedures independent of temperature and other variables may affect the estimation of upper critical temperatures. Therefore, based on our data, we offer suggestions to enhance the quality of measurements, and offer recommendations to

  11. A comparison of urban heat islands mapped using skin temperature, air temperature, and apparent temperature (Humidex), for the greater Vancouver area.

    PubMed

    Ho, Hung Chak; Knudby, Anders; Xu, Yongming; Hodul, Matus; Aminipouri, Mehdi

    2016-02-15

    Apparent temperature is more closely related to mortality during extreme heat events than other temperature variables, yet spatial epidemiology studies typically use skin temperature (also known as land surface temperature) to quantify heat exposure because it is relatively easy to map from satellite data. An empirical approach to map apparent temperature at the neighborhood scale, which relies on publicly available weather station observations and spatial data layers combined in a random forest regression model, was demonstrated for greater Vancouver, Canada. Model errors were acceptable (cross-validated RMSE=2.04 °C) and the resulting map of apparent temperature, calibrated for a typical hot summer day, corresponded well with past temperature research in the area. A comparison with field measurements as well as similar maps of skin temperature and air temperature revealed that skin temperature was poorly correlated with both air temperature (R(2)=0.38) and apparent temperature (R(2)=0.39). While the latter two were more similar (R(2)=0.87), apparent temperature was predicted to exceed air temperature by more than 5 °C in several urban areas as well as around the confluence of the Pitt and Fraser rivers. We conclude that skin temperature is not a suitable proxy for human heat exposure, and that spatial epidemiology studies could benefit from mapping apparent temperature, using an approach similar to the one reported here, to better quantify differences in heat exposure that exist across an urban landscape.

  12. The EUSTACE project: delivering global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Morice, C. P.; Rayner, N. A.; Auchmann, R.; Bessembinder, J.; Bronnimann, S.; Brugnara, Y.; Conway, E. A.; Ghent, D.; Good, E.; Herring, K.; Kennedy, J.; Lindgren, F.; Madsen, K. S.; Merchant, C. J.; van der Schrier, G.; Stephens, A.; Tonboe, R. T.; Waterfall, A. M.; Mitchelson, J.; Woolway, I.

    2015-12-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. These relationships can be derived either empirically or with the help of a physical model.Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals would be used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods.We will present plans and progress along this road in the EUSTACE project (2015-June 2018), i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras.Information will also be given on how interested users can become

  13. A study of the adsorption of NH 3 and SO 2 on leaf surfaces

    NASA Astrophysics Data System (ADS)

    Van Hove, L. W. A.; Adema, E. H.; Vredenberg, W. J.; Pieters, G. A.

    The adsorption of NH 3 and SO 2 on the external leaf surface of bean ( Phaseolus vulgaris L.) and poplar ( Populus euramericana L.) was studied. The adsorbed quantities increased strongly with increasing air humidity, indicating that water on the leaf surface plays a major role in the interaction of these gases with the leaf surface. On the other hand temperature in the range between 15 and 26°C had no significant influence. The adsorbed quantities of NH 3 at a specific air humidity appeared to be proportional to NH 3 concentration. This proportionality was less clear for SO 2. The affinity of SO 2 for the leaf surface was found to be approximately twice that of NH 3. A mixture of these gases in the air mutually stimulated their adsorption on the leaf. No significant desorption or uptake of these gases through the cuticle could be detected, indicating that the bulk of the adsorbed gases remains associated with the cuticle.

  14. Air-Cooled Design of a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization Systems

    NASA Technical Reports Server (NTRS)

    Mulloth, Lila M.; Affleck, Dave L.; Rosen, Micha; LeVan, M. Douglas; Wang, Yuan; Cavalcante, Celio L.

    2004-01-01

    The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no rapidly moving parts. This paper discusses the mechanical design and the results of thermal model validation tests of a TSAC that uses air as the cooling medium.

  15. Some Effects of Air and Fuel Oil Temperatures on Spray Penetration and Dispersion

    NASA Technical Reports Server (NTRS)

    Gelalles, A G

    1930-01-01

    Presented here are experimental results obtained from a brief investigation of the appearance, penetration, and dispersion of oil sprays injected into a chamber of highly heated air at atmospheric pressure. The development of single sprays injected into a chamber containing air at room temperature and at high temperature was recorded by spray photography equipment. A comparison of spray records showed that with the air at the higher temperature, the spray assumed the appearance of thin, transparent cloud, the greatest part of which rapidly disappeared from view. With the chamber air at room temperature, a compact spray with an opaque core was obtained. Measurements of the records showed a decrease in penetration and an increase in the dispersion of the spray injected into the heated air. No ignition of the fuel injected was observed or recorded until the spray particles came in contact with the much hotter walls of the chamber about 0.3 second after the start of injection.

  16. Multi-fractal scaling comparison of the Air Temperature and the Surface Temperature over China

    NASA Astrophysics Data System (ADS)

    Jiang, Lei; Zhang, Jiping; Liu, Xinwei; Li, Fei

    2016-11-01

    The spatial and temporal multi-scaling behaviors between the daily Air Temperature (AT) and the Surface Temperature (ST) over China are compared in about 60-yr observations by Multi-fractal Detrended Fluctuation Analysis (MF-DFA) method. The different fractal phenomena and diversity features in the geographic distribution are found for the AT and ST series using MF-DFA. There are more multi-fractal features for the AT records but less for ST. The respective geographic sites show important scaling differences when compared to the multi-fractal signatures of AT with ST. An interval threshold for 95% confidence level is obtained by shuffling the AT records and the ST records. For the AT records, 93% of all observed stations shows the strong multi-fractal behaviors. In addition, the multi-fractal characteristics decrease with increasing latitude in South China and are obviously strong along the coast. The multi-fractal behaviors of the AT records between the Yangtze River and Yellow River basin and in most regions of Northwest China seem to be weak and not significant, even single mono-fractal features. However, for the ST records, the geographical distributions of multi-fractal phenomenon seem to be in disorder which account for 81% of the stations. The weak multi-fractal behaviors of the ST records are concentrated in North China, most regions of Northeast China.

  17. Attribution of precipitation changes on ground-air temperature offset: Granger causality analysis

    NASA Astrophysics Data System (ADS)

    Cermak, Vladimir; Bodri, Louise

    2016-06-01

    This work examines the causal relationship between the value of the ground-air temperature offset and the precipitation changes for monitored 5-min data series together with their hourly and daily averages obtained at the Sporilov Geophysical Observatory (Prague). Shallow subsurface soil temperatures were monitored under four different land cover types (bare soil, sand, short-cut grass and asphalt). The ground surface temperature (GST) and surface air temperature (SAT) offset, ΔT(GST-SAT), is defined as the difference between the temperature measured at the depth of 2 cm below the surface and the air temperature measured at 5 cm above the surface. The results of the Granger causality test did not reveal any evidence of Granger causality for precipitation to ground-air temperature offsets on the daily scale of aggregation except for the asphalt pavement. On the contrary, a strong evidence of Granger causality for precipitation to the ground-air temperature offsets was found on the hourly scale of aggregation for all land cover types except for the sand surface cover. All results are sensitive to the lag choice of the autoregressive model. On the whole, obtained results contain valuable information on the delay time of ΔT(GST-SAT) caused by the rainfall events and confirmed the importance of using autoregressive models to understand the ground-air temperature relationship.

  18. Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

    NASA Technical Reports Server (NTRS)

    Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

    2016-01-01

    This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

  19. Investigation of the impact of extreme air temperature on river water temperature: case study of the heat episode 2013.

    NASA Astrophysics Data System (ADS)

    Weihs, Philipp; Trimmel, Heidelinde; Goler, Robert; Formayer, Herbert; Holzapfel, Gerda; Rauch, Hans Peter

    2014-05-01

    Water stream temperature is a relevant factor for water quality since it is an important driver of water oxygen content and in turn also reduces or increases stress on the aquatic fauna. The water temperature of streams is determined by the source and inflow water temperature, by the energy balance at the stream surface and by the hydrological regime of the stream. Main factors driving the energy balance of streams are radiation balance and air temperature which influences the sensitive and latent heat flux. The present study investigates the impact of the heat episode of summer 2013 on water temperature of two lowland rivers in south eastern Austria. Within the scope of the project BIO_CLIC routine measurements of water temperature at 33 locations alongside the rivers Pinka and Lafnitz have been performed since spring 2012. In addition meteorological measurements of global shortwave and longwave radiation, air temperature, wind and air humidity have been carried out during this time. For the same time period, data of discharge and water levels of both rivers were provided by the public hydrological office. The heat episode of summer 2013 started, according to the Kysely- definition, on 18 July and lasted until 14 August. The highest air temperature ever recorded in Austria was reported on 8 August at 40.5°C. In Güssing, which is located within the project area, 40.0 °C were recorded. In the lower reaches of the river Pinka, at the station Burg the monthly mean water temperature of August 2013 was with more than 22°C, 1°C higher than the mean water temperature of the same period of the previous years. At the same station, the maximum water temperature of 27.1°C was recorded on 29 July, 9 days prior to the air temperature record. Analysis shows that at the downstream stations the main driving parameter is solar radiation whereas at the upstream stations a better correlation between air temperature and water temperature is obtained. Using the extensive data set

  20. Comparison of Near-Surface Air Temperatures and MODIS Ice-Surface Temperatures at Summit, Greenland (2008-2013)

    NASA Technical Reports Server (NTRS)

    Shuman, Christopher A.; Hall, Dorothy K.; DiGirolamo, Nicolo E.; Mefford, Thomas K.; Schnaubelt, Michael J.

    2014-01-01

    We have investigated the stability of the MODerate resolution Imaging Spectroradiometer (MODIS) infrared-derived ice surface temperature (IST) data from Terra for use as a climate quality data record. The availability of climate quality air temperature data (TA) from a NOAA Global Monitoring Division observatory at Greenlands Summit station has enabled this high temporal resolution study of MODIS ISTs. During a 5 year period (July 2008 to August 2013), more than 2500 IST values were compared with 3-minute average TA values derived from the 1-minute data from NOAAs primary 2 m air temperature sensor. These data enabled an expected small offset between air and surface temperatures at this the ice sheet location to be investigated over multiple annual cycles.

  1. Geographical and Geomorphological Effects on Air Temperatures in the Columbia Basin's Signature Vineyards

    NASA Astrophysics Data System (ADS)

    Olson, L.; Pogue, K. R.; Bader, N.

    2012-12-01

    The Columbia Basin of Washington and Oregon is one of the most productive grape-growing areas in the United States. Wines produced in this region are influenced by their terroir - the amalgamation of physical and cultural elements that influence grapes grown at a particular vineyard site. Of the physical factors, climate, and in particular air temperature, has been recognized as a primary influence on viticulture. Air temperature directly affects ripening in the grapes. Proper fruit ripening, which requires precise and balanced levels of acid and sugar, and the accumulation of pigment in the grape skin, directly correlates with the quality of wine produced. Many features control air temperature within a particular vineyard. Elevation, latitude, slope, and aspect all converge to form complex relationships with air temperatures; however, the relative degree to which these attributes affect temperatures varies between regions and is not well understood. This study examines the influence of geography and geomorphology on air temperatures within the American Viticultural Areas (AVAs) of the Columbia Basin in eastern Washington and Oregon. The premier vineyards within each AVA, which have been recognized for producing high-quality wine, were equipped with air temperature monitoring stations that collected hourly temperature measurements. A variety of temperature statistics were calculated, including daily average, maximum, and minimum temperatures. From these values, average diurnal variation and growing degree-days (10°C) were calculated. A variety of other statistics were computed, including date of first and last frost and time spent below a minimum temperature threshold. These parameters were compared to the vineyard's elevation, latitude, slope, aspect, and local topography using GPS, ArcCatalog, and GIS in an attempt to determine their relative influences on air temperatures. From these statistics, it was possible to delineate two trends of temperature variation

  2. Modeling Validation and Control Analysis for Controlled Temperature and Humidity of Air Conditioning System

    PubMed Central

    Lee, Jing-Nang; Lin, Tsung-Min

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system. PMID:25250390

  3. Modeling validation and control analysis for controlled temperature and humidity of air conditioning system.

    PubMed

    Lee, Jing-Nang; Lin, Tsung-Min; Chen, Chien-Chih

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14 °C, 0006 kg(w)/kg(da) in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system.

  4. Perceiving nasal patency through mucosal cooling rather than air temperature or nasal resistance.

    PubMed

    Zhao, Kai; Blacker, Kara; Luo, Yuehao; Bryant, Bruce; Jiang, Jianbo

    2011-01-01

    Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive. The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool.

  5. Analysis of surface air temperature variations and local urbanization effects on central Yunnan Plateau, SW China

    NASA Astrophysics Data System (ADS)

    He, Yunling; Wu, Zhijie; Liu, Xuelian; Deng, Fuying

    2016-10-01

    With the surface air temperature (SAT) data at 37 stations on Central Yunnan Plateau (CYP) for 1961-2010 and the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime light data, the temporal-spatial patterns of the SAT trends are detected using Sen's Nonparametric Estimator of Slope approach and MK test, and the impact of urbanization on surface warming is analyzed by comparing the differences between the air temperature change trends of urban stations and their corresponding rural stations. Results indicated that annual mean air temperature showed a significant warming trend, which is equivalent to a rate of 0.17 °C/decade during the past 50 years. Seasonal mean air temperature presents a rising trend, and the trend was more significant in winter (0.31 °C/decade) than in other seasons. Annual/seasonal mean air temperature tends to increase in most areas, and higher warming trend appeared in urban areas, notably in Kunming city. The regional mean air temperature series was significantly impacted by urban warming, and the urbanization-induced warming contributed to approximately 32.3-62.9 % of the total regional warming during the past 50 years. Meantime, the urbanization-induced warming trend in winter and spring was more significant than that in summer and autumn. Since 1985, the urban heat island (UHI) intensity has gradually increased. And the urban temperatures always rise faster than rural temperatures on the CYP.

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

    NASA Astrophysics Data System (ADS)

    Whiteman, C. David; 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 pseudovertical temperature “soundings” from three lines of temperature dataloggers on the basin's northwest, southwest, and southeast sidewalls. Under stable nighttime conditions with low background winds, the pseudovertical 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 dataloggers to sunlight made the pseudovertical 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 can be used to monitor temperatures, temperature gradients, and temperature inversion evolution in the sinkhole. Sidewall soundings can produce more frequent profiles at lower cost than can tethersondes or rawinsondes, and extension of these findings to other enclosed or semienclosed topographies may enhance future basic meteorological research or support applications studies in agriculture, forestry, air pollution, and land use planning.


  7. Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions

    NASA Technical Reports Server (NTRS)

    Wang, Y.; Gupta, A. K.

    2001-01-01

    The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

  8. Multichannel temperature controller for hot air solar house

    NASA Technical Reports Server (NTRS)

    Currie, J. R.

    1979-01-01

    This paper describes an electronic controller that is optimized to operate a hot air solar system. Thermal information is obtained from copper constantan thermocouples and a wall-type thermostat. The signals from the thermocouples are processed through a single amplifier using a multiplexing scheme. The multiplexing reduces the component count and automatically calibrates the thermocouple amplifier. The processed signals connect to some simple logic that selects one of the four operating modes. This simple, inexpensive, and reliable scheme is well suited to control hot air solar systems.

  9. High-precision diode-laser-based temperature measurement for air refractive index compensation

    SciTech Connect

    Hieta, Tuomas; Merimaa, Mikko; Vainio, Markku; Seppae, Jeremias; Lassila, Antti

    2011-11-01

    We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlen equations, where the dominant uncertainty component is in most cases the air temperature. The method developed in this work utilizes direct absorption spectroscopy of oxygen to measure the average temperature of air and of water vapor to measure relative humidity. The method allows measurement of temperature and humidity over the same beam path as in optical distance measurement, providing spatially well-matching data. Indoor and outdoor measurements demonstrate the effectiveness of the method. In particular, we demonstrate an effective compensation of the refractive index of air in an interferometric length measurement at a time-variant and spatially nonhomogeneous temperature over a long time period. Further, we were able to demonstrate 7 mK RMS noise over a 67 m path length using a 120 s sample time. To our knowledge, this is the best temperature precision reported for a spectroscopic temperature measurement.

  10. Do the rich always become richer? Characterizing the leaf physiological response of the high-yielding rice cultivar Takanari to free-air CO2 enrichment.

    PubMed

    Chen, Charles P; Sakai, Hidemitsu; Tokida, Takeshi; Usui, Yasuhiro; Nakamura, Hirofumi; Hasegawa, Toshihiro

    2014-02-01

    The development of crops which are well suited to growth under future environmental conditions such as higher atmospheric CO2 concentrations ([CO2]) is essential to meeting the challenge of ensuring food security in the face of the growing human population and changing climate. A high-yielding indica rice variety (Oryza sativa L. cv. Takanari) has been recently identified as a potential candidate for such breeding, due to its high productivity in present [CO2]. To test if it could further increase its productivity under elevated [CO2] (eCO2), Takanari was grown in the paddy field under season-long free-air CO2 enrichment (FACE, approximately 200 µmol mol(-1) above ambient [CO2]) and its leaf physiology was compared with the representative japonica variety 'Koshihikari'. Takanari showed consistently higher midday photosynthesis and stomatal conductance than Koshihikari under both ambient and FACE growth conditions over 2 years. Maximum ribulose-1,5-bisphosphate carboxylation and electron transport rates were higher for Takanari at the mid-grain filling stage in both years. Mesophyll conductance was higher in Takanari than in Koshihikari at the late grain-filling stage. In contrast to Koshihikari, Takanari grown under FACE conditions showed no decrease in total leaf nitrogen on an area basis relative to ambient-grown plants. Chl content was higher in Takanari than in Koshihikari at the same leaf nitrogen level. These results indicate that Takanari maintains its superiority over Koshihikari in regards to its leaf-level productivity when grown in elevated [CO2] and it may be a valuable resource for rice breeding programs which seek to increase crop productivity under current and future [CO2].

  11. Wind speed effects on leaf energy balance, transpiration and water use efficiency

    NASA Astrophysics Data System (ADS)

    Schymanski, S. J.; Or, D.

    2014-12-01

    Transpiration and heat exchange rates by plant leaves involve coupled physiological processes of significant ecohydrological importance. Prediction of the effects of changing environmental conditions such as irradiance, temperature, humidity and wind speed requires a thorough understanding of these processes. The common assumption that leaf temperature equals air temperature may introduce significant bias into estimates of transpiration rates and water use efficiency (WUE, the amount of carbon gained by photosynthesis per unit of water lost by transpiration). Theoretical considerations and observations suggest that leaf temperatures may deviate substantially from air temperature under typical environmental conditions, leading to greatly modified transpiration rates compared to isothermal conditions. In particular, effects of wind on gas exchange must consider feedbacks with leaf temperature. Systematic quantification of the effects of wind speed on leaf heat and gas exchange rates yield some surprising insights. We found a range of conditions where increased wind speed can suppress transpiration rates. The result reflects unintuitive feedbacks between sensible heat flux, leaf temperature, leaf-to-air vapour pressure deficit and latent heat flux. Modelling results suggest that with high wind speeds the same leaf conductance (for water vapour and carbon dioxide) can be maintained with less evaporative losses. This leads to positive relation between water use efficiency and wind speed across a wide range of conditions. The presentation will report results from a lab experiment allowing separation of the different leaf energy balance components under fully controlled conditions (wind speed, temperature, humidity, irradiance) and put them into perspective with a detailed leaf energy balance model and the commonly used Penman-Monteith equation.

  12. Does the direct effect of atmospheric CO2 concentration on leaf respiration vary with temperature? Responses in two species of Plantago that differ in relative growth rate.

    PubMed

    Bruhn, Dan; Mikkelsen, Teis N.; Atkin, Owen K.

    2002-01-01

    The objective of this study was to investigate the direct effect of elevated atmospheric CO2 concentrations on leaf respiration in darkness (R) over a broad range of measurement temperatures. Our aim was to further elucidate the underlying mechanism(s) of the often-reported inhibition of leaf R by a doubling of the atmospheric CO2 concentration. Experiments were conducted using two species of Plantago that differed in maximum relative growth rate (fast-growing Plantago lanceolata L. and the slow-growing P. euryphylla Briggs, Carolin & Pulley). Rates of leaf respiration (R) were measured at atmospheric CO2 concentrations ranging from 75 to 2000 &mgr;mol mol-1 at temperatures from 12 to 42 degrees C. R was measured as CO2 release with a portable gas exchange system with infrared gas analysers. Our hypothesis was that the changes in temperature alter the flux coefficient (i.e. the extent to which changes in potential enzyme activity has an effect on the rate of a reaction) of enzymes potentially affected by CO2. Initial analysis of our results suggested that R was inhibited by elevated CO2 in both species, with the apparent degree of inhibition being greatest at low temperature. Moreover, the apparent degree of inhibition following a doubling of atmospheric CO2 concentration from 350 to 700 &mgr;mol mol-1 was similar to that reported by several previous studies (approximately 14% and 26% for P. lanceolata and P. euryphylla, respectively) at a temperature equal to the mean of the previous studies. However, subsequent correction for diffusion leaks of CO2 across the gas exchange's cuvette gaskets revealed that no significant inhibition had occurred in either species, at any temperature. The inhibitory effect of elevated CO2 on leaf respiratory CO2 release reported by previous studies may therefore have been overestimated.

  13. Effects of root morphology and leaf transpiration on Cd uptake and translocation in rice under different growth temperature.

    PubMed

    Ge, Liqiang; Cang, Long; Yang, Jie; Zhou, Dongmei

    2016-12-01

    With growing concerns on cadmium (Cd) contamination of rice grain from the public, the mechanism about the uptake and translocation of Cd in rice plant has been widely studied in recent years. However, the study about the effects of future warming on rice Cd accumulation was almost neglected. In the paper, hydroponic experiments of Cd exposure in growth chambers under different growth temperature (asymmetric and symmetric warming) were conducted to investigate how warming influenced Cd uptake and translocation in rice seedlings (6 liangyou 9368). The results showed that warming significantly increased Cd accumulation in shoot and root by 62.7 to 122 % and 65.5 to 73.9 %, respectively. Moreover, symmetric warming boosted Cd translocation from root to shoot, while antitranspirant treatment inhibited it significantly. The possible mechanisms may be that warming increased the fine root (diameter ≤ 0.5 mm) surface area and enlarged the active sites on root surface by influencing root morphology growth, thus promoted Cd uptake by root. Meanwhile, warming increased leaf transpiration and boosted the xylem stream from nutrient solution to above organs, thus enhanced Cd translocation. This study may provide new understanding and possible explanations about Cd uptake and translocation in rice plant under future warming.

  14. Effect of optimizing supply water temperature and air volume on a VAV system

    SciTech Connect

    Karino, Naoki; Shiba, Takashi; Ito, Koichi; Yokoyama, Ryohei

    1999-07-01

    An optimal planning method is proposed for an air conditioning system composed of heat pump chillers and variable air volume (VAV) units. Supply water temperature, supply air volume, and thickness of heat insulation material are determined optimally so as to minimize the annual total cost of the system in consideration of equipment capacities and annual operation for the cooling load varying through a year. Through a numerical study on the system planned for an office building, influences of supply water/air temperatures and air volume on the system are investigated from the viewpoint of long-term economics. As a result, it is shown that the annual energy charge of the optimal VAV system can be reduced considerably in comparison with that of the optimal constant air volume (CAV) system, and that the effect of the energy conservation of the former system is large enough.

  15. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    PubMed Central

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  16. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-11-10

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.

  17. Oxide modified air electrode surface for high temperature electrochemical cells

    DOEpatents

    Singh, Prabhakar; Ruka, Roswell J.

    1992-01-01

    An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

  18. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    R.K. Johnson

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

  19. Improved Temperature Sounding and Quality Control Methodology Using AIRS/AMSU Data: The AIRS Science Team Version 5 Retrieval Algorithm

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John M.; Iredell, Lena; Keita, Fricky

    2009-01-01

    This paper describes the AIRS Science Team Version 5 retrieval algorithm in terms of its three most significant improvements over the methodology used in the AIRS Science Team Version 4 retrieval algorithm. Improved physics in Version 5 allows for use of AIRS clear column radiances in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of clear column radiances .R(sub i) for all channels. This new approach allows for the generation of more accurate values of .R(sub i) and T(p) under most cloud conditions. Secondly, Version 5 contains a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 also contains for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology, referred to as AIRS Version 5 AO, was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Results are shown comparing the relative performance of the AIRS Version 4, Version 5, and Version 5 AO for the single day, January 25, 2003. The Goddard DISC is now generating and distributing products derived using the AIRS Science Team Version 5 retrieval algorithm. This paper also described the Quality Control flags contained in the DISC AIRS/AMSU retrieval products and their intended use for scientific research purposes.

  20. Estimation of Surface Air Temperature Over Central and Eastern Eurasia from MODIS Land Surface Temperature

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.

    2011-01-01

    Surface air temperature (T(sub a)) is a critical variable in the energy and water cycle of the Earth.atmosphere system and is a key input element for hydrology and land surface models. This is a preliminary study to evaluate estimation of T(sub a) from satellite remotely sensed land surface temperature (T(sub s)) by using MODIS-Terra data over two Eurasia regions: northern China and fUSSR. High correlations are observed in both regions between station-measured T(sub a) and MODIS T(sub s). The relationships between the maximum T(sub a) and daytime T(sub s) depend significantly on land cover types, but the minimum T(sub a) and nighttime T(sub s) have little dependence on the land cover types. The largest difference between maximum T(sub a) and daytime T(sub s) appears over the barren and sparsely vegetated area during the summer time. Using a linear regression method, the daily maximum T(sub a) were estimated from 1 km resolution MODIS T(sub s) under clear-sky conditions with coefficients calculated based on land cover types, while the minimum T(sub a) were estimated without considering land cover types. The uncertainty, mean absolute error (MAE), of the estimated maximum T(sub a) varies from 2.4 C over closed shrublands to 3.2 C over grasslands, and the MAE of the estimated minimum Ta is about 3.0 C.

  1. Preliminary verification of instantaneous air temperature estimation for clear sky conditions based on SEBAL

    NASA Astrophysics Data System (ADS)

    Zhu, Shanyou; Zhou, Chuxuan; Zhang, Guixin; Zhang, Hailong; Hua, Junwei

    2017-02-01

    Spatially distributed near surface air temperature at the height of 2 m is an important input parameter for the land surface models. It is of great significance in both theoretical research and practical applications to retrieve instantaneous air temperature data from remote sensing observations. An approach based on Surface Energy Balance Algorithm for Land (SEBAL) to retrieve air temperature under clear sky conditions is presented. Taking the meteorological measurement data at one station as the reference and remotely sensed data as the model input, the research estimates the air temperature by using an iterative computation. The method was applied to the area of Jiangsu province for nine scenes by using MODIS data products, as well as part of Fujian province, China based on four scenes of Landsat 8 imagery. Comparing the air temperature estimated from the proposed method with that of the meteorological station measurement, results show that the root mean square error is 1.7 and 2.6 °C at 1000 and 30 m spatial resolution respectively. Sensitivity analysis of influencing factors reveals that land surface temperature is the most sensitive to the estimation precision. Research results indicate that the method has great potentiality to be used to estimate instantaneous air temperature distribution under clear sky conditions.

  2. A Review of the Thermodynamic, Transport, and Chemical Reaction Rate Properties of High-temperature Air

    NASA Technical Reports Server (NTRS)

    Hansen, C Frederick; Heims, Steve P

    1958-01-01

    Thermodynamic and transport properties of high temperature air, and the reaction rates for the important chemical processes which occur in air, are reviewed. Semiempirical, analytic expressions are presented for thermodynamic and transport properties of air. Examples are given illustrating the use of these properties to evaluate (1) equilibrium conditions following shock waves, (2) stagnation region heat flux to a blunt high-speed body, and (3) some chemical relaxation lengths in stagnation region flow.

  3. Influence of low air humidity and low root temperature on water uptake, growth and aquaporin expression in rice plants.

    PubMed

    Kuwagata, Tsuneo; Ishikawa-Sakurai, Junko; Hayashi, Hidehiro; Nagasuga, Kiyoshi; Fukushi, Keiko; Ahamed, Arifa; Takasugi, Katsuko; Katsuhara, Maki; Murai-Hatano, Mari

    2012-08-01

    The effects of low air humidity and low root temperature (LRT) on water uptake, growth and aquaporin gene expression were investigated in rice plants. The daily transpiration of the plants grown at low humidity was 1.5- to 2-fold higher than that at high humidity. LRT at 13°C reduced transpiration, and the extent was larger at lower humidity. LRT also reduced total dry matter production and leaf area expansion, and the extent was again larger at lower humidity. These observations suggest that the suppression of plant growth by LRT is associated with water stress due to decreased water uptake ability of the root. On the other hand, the net assimilation rate was not affected by low humidity and LRT, and water use efficiency was larger for LRT. We found that low humidity induced coordinated up-regulation of many PIP and TIP aquaporin genes in both the leaves and the roots. Expression levels of two root-specific aquaporin genes, OsPIP2;4 and OsPIP2;5, were increased significantly after 6 and 13 d of LRT exposure. Taken together, we discuss the possibility that aquaporins are part of an integrated response of this crop to low air humidity and LRT.

  4. Assessing the Potential of the AIRS Retrieved Surface Temperature for 6-Hour Average Temperature Forecast in River Forecast Centers

    NASA Astrophysics Data System (ADS)

    Ding, F.; Theobald, M.; Vollmer, B.; Savtchenko, A. K.; Hearty, T. J.; Esfandiari, A. E.

    2012-12-01

    Producing timely and accurate water forecast and information is the mission of National Weather Service River Forecast Centers (NWS RFCs) of National Oceanic and Atmospheric Administration (NOAA). The river forecast system in RFCs requires average surface temperature in the fixed 6-hour period 000-0600, 0600-1200, 1200-1800, and 1200-0000 UTC. The current logic of RFC temperature forecast relies on ingest of point values of daytime maximum and nighttime minimum temperature. Meanwhile, the mean temperature for the 6-hour period is estimated from a weighted average of daytime maximum and nighttime minimum temperature. The Atmospheric Infrared Sounder (AIRS) in the first high spectral resolution infrared sounder on board the Aqua satellite which was launched in May 2002 and follows a Sun-synchronous polar orbit. It is aimed to produce high resolution atmospheric profile and surface atmospheric parameters. As Aqua crosses the equator at about 1330 and 0130 local time, the AIRS retrieved surface temperature may represent daytime maximum and nighttime minimum value. Comparing to point observation from surface weather stations which are often sparse over the less-populated area and are unevenly distributed, satellite may obtain better area averaged observation. This test study assesses the potential of using AIRS retrieved surface temperature to forecast 6-hour average temperature for NWS RFCs. The California Nevada RFC is selected due to the poor coverage of surface observation in the mountainous region and spring snow melting. The study focuses on the March to May spring season when water from snowpack melting often plays important role in flood. AIRS retrieved temperature and surface weather station data set will be used to derive statistical weighting coefficient for 6-hour average temperature forecast. The resulting forecast biases and errors will be the main indicators of the potential usage. All study results will be presented in the meeting.

  5. Transport properties of high-temperature air in a magnetic field

    SciTech Connect

    Bruno, D.; Capitelli, M.; Catalfamo, C.; Giordano, D.

    2011-01-15

    Transport properties of equilibrium air plasmas in a magnetic field are calculated with the Chapman-Enskog method. The range considered for the temperature is [50-50 000] K and for the magnetic induction is [0-300] T.

  6. Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  7. Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  8. High-temperature stabilization by air of a pyrophoric catalyst for the synthesis of ammonia

    SciTech Connect

    Krylova, A.V.; Ustimenko, G.A.

    1982-12-01

    The reaction of a catalyst for the synthesis of ammonia with air at 480 to 520/sup 0/C leads to the formation on the surface of a thin protective oxide structure that eliminates its pyrophoric character. High-temperature stabilization by air is a considerably faster process than passivation and leads to the production of catalysts with increased resistance to oxidation.

  9. Temperature and Humidity Independent Control Research on Ground Source Heat Pump Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Chen, G.; Wang, L. L.

    Taking green demonstration center building air conditioning system as an example, this paper presents the temperature and humidity independent control system combined with ground source heat pump system, emphasis on the design of dry terminal device system, fresh air system and ground source heat pump system.

  10. Improving Forecast Skill by Assimilation of Quality-controlled AIRS Temperature Retrievals under Partially Cloudy Conditions

    NASA Technical Reports Server (NTRS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Riishojgaard, L.; Liu, E.; Terry, J.; Jusem, J. C.

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite has been long recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  11. Improving forecast skill by assimilation of quality-controlled AIRS temperature retrievals under partially cloudy conditions

    NASA Astrophysics Data System (ADS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Liu, E.; Riishojgaard, L. P.; Terry, J.; Jusem, J. C.

    2008-04-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite is now recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  12. Modelling the impact of room temperature on concentrations of polychlorinated biphenyls (PCBs) in indoor air.

    PubMed

    Lyng, Nadja Lynge; Clausen, Per Axel; Lundsgaard, Claus; Andersen, Helle Vibeke

    2016-02-01

    Buildings contaminated with polychlorinated biphenyls (PCBs) are a health concern for the building occupants. Inhalation exposure is linked to indoor air concentrations of PCBs, which are known to be affected by indoor temperatures. In this study, a highly PCB contaminated room was heated to six temperature levels between 20 and 30 C, i.e. within the normal fluctuation of indoor temperatures, while the air exchange rate was constant. The steady-state air concentrations of seven PCBs were determined at each temperature level. A model based on Clausius-Clapeyron equation, ln(P) = -ΔH/RT + a(0), where changes in steady-state air concentrations in relation to temperature, was tested. The model was valid for PCB-28, PCB-52 and PCB-101; the four other congeners were sporadic or non-detected. For each congener, the model described a large proportion (R(2)>94%) of the variation in indoor air PCB levels. The results showed that one measured concentration of PCB at a known steady-state temperature can be used to predict the steady-state concentrations at other temperatures under circumstances where e.g. direct sunlight does not influence temperatures and the air exchange rate is constant. The model was also tested on field data from a PCB remediation case in an apartment in another contaminated building complex where PCB concentrations and temperature were measured simultaneously and regularly throughout one year. The model fitted relatively well with the regression of measured PCB air concentrations, ln(P) vs. 1/T, at varying temperature between 16.3 and 28.2 °C, even though the measurements were carried out under uncontrolled environmental condition.

  13. 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.

  14. 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.

  15. A study on the interplay between energy and matter transformation: the effect of elevated temperatures on the leaf morphology of Vitis vinifera var. Merlot.

    PubMed

    Maze, Jack; Bowen, Patricia; Bogdanoff, Carl

    2003-12-01

    This investigation explores the relationship between increased energy levels and leaf morphology. It tests the idea that the causal agent of development is the dissipation of energy into transformed matter. The energy under which leaves developed was modified by increasing temperatures in grape cordons through wrapping them in clear plastic sleeves in the early spring. At the higher temperatures, and energy levels, there was a small but statistically significant decrease in leaf size and a change in organization the leaves. The decrease in leaf size may be due to a reallocation of resources, either to greater shoot growth as a previous study demonstrated or to the appearance of more vectors of development in the leaves, i.e. the appearance of more developmental subsystems. The leaves that grew under the higher temperature regime were more complex, perhaps indicating that the grapes on those same vines may produce more complex juice, another expression of more developmental subsystems. The change in organization in these leaves that developed at higher temperature argues that the causal agent in plant development is energy dissipation and the concomitant transformation of matter, the latter expressed in the appearance of more growth vectors.

  16. Rate constants for chemical reactions in high-temperature nonequilibrium air

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.

    1986-01-01

    In the nonequilibrium atmospheric chemistry regime that will be encountered by the proposed Aeroassisted Orbital Transfer Vehicle in the upper atmosphere, where air density is too low for thermal and chemical equilibrium to be maintained, the detailed high temperature air chemistry plays a critical role in defining radiative and convective heating loads. Although vibrational and electronic temperatures remain low (less than 15,000 K), rotational and translational temperatures may reach 50,000 K. Attention is presently given to the effects of multiple temperatures on the magnitudes of various chemical reaction rate constants, for the cases of both bimolecular exchange reactions and collisional excitation and dissociation reactions.

  17. Emperor penguin body surfaces cool below air temperature

    PubMed Central

    McCafferty, D. J.; Gilbert, C.; Thierry, A.-M.; Currie, J.; Le Maho, Y.; Ancel, A.

    2013-01-01

    Emperor penguins Aptenodytes forsteri are able to survive the harsh Antarctic climate because of specialized anatomical, physiological and behavioural adaptations for minimizing heat loss. Heat transfer theory predicts that metabolic heat loss in this species will mostly depend on radiative and convective cooling. To examine this, thermal imaging of emperor penguins was undertaken at the breeding colony of Pointe Géologie in Terre Adélie (66°40′ S 140° 01′ E), Antarctica in June 2008. During clear sky conditions, most outer surfaces of the body were colder than surrounding sub-zero air owing to radiative cooling. In these conditions, the feather surface will paradoxically gain heat by convection from surrounding air. However, owing to the low thermal conductivity of plumage any heat transfer to the skin surface will be negligible. Future thermal imaging studies are likely to yield further insights into the adaptations of this species to the Antarctic climate. PMID:23466479

  18. Cavity Ring Down Absorption of Oxygen in Air as a Temperature Sensor

    NASA Astrophysics Data System (ADS)

    Manzanares, Carlos; Nyaupane, Parashu R.

    2016-06-01

    The A-band of oxygen has been measured at low resolution at temperatures between 90 K and 373 K using the phase shift cavity ring down (PS-CRD) technique. For temperatures between 90 K and 295 K, the PS-CRD technique presented here involves an optical cavity attached to a cryostat. The static cell and mirrors of the optical cavity are all inside a vacuum chamber at the same temperature of the cryostat. The temperature of the cell can be changed between 77 K and 295 K. For temperatures above 295 K, a hollow glass cylindrical tube without windows has been inserted inside an optical cavity to measure the temperature of air flowing through the tube. The cavity consists of two highly reflective mirrors which are mounted parallel to each other and separated by a distance of 93 cm. In this experiment, air is passed through a heated tube. The temperature of the air flowing through the tube is determined by measuring the intensity of the oxygen absorption as a function of the wavenumber. The A-band of oxygen is measured between 298 K and 373 K, with several air flow rates. Accuracy of the temperature measurement is determined by comparing the calculated temperature from the spectra with the temperature obtained from a calibrated thermocouple inserted at the center of the tube.

  19. The influence of leaf size and shape on leaf thermal dynamics: does theory hold up under natural conditions?

    PubMed

    Leigh, A; Sevanto, S; Close, J D; Nicotra, A B

    2017-02-01

    Laboratory studies on artificial leaves suggest that leaf thermal dynamics are strongly influenced by the two-dimensional size and shape of leaves and associated boundary layer thickness. Hot environments are therefore said to favour selection for small, narrow or dissected leaves. Empirical evidence from real leaves under field conditions is scant and traditionally based on point measurements that do not capture spatial variation in heat load. We used thermal imagery under field conditions to measure the leaf thermal time constant (τ) in summer and the leaf-to-air temperature difference (∆T) and temperature range across laminae (Trange ) during winter, autumn and summer for 68 Proteaceae species. We investigated the influence of leaf area and margin complexity relative to effective leaf width (we ), the latter being a more direct indicator of boundary layer thickness. Normalized difference of margin complexity had no or weak effects on thermal dynamics, but we strongly predicted τ and ∆T, whereas leaf area influenced Trange . Unlike artificial leaves, however, spatial temperature distribution in large leaves appeared to be governed largely by structural variation. Therefore, we agree that small size, specifically we , has adaptive value in hot environments but not with the idea that thermal regulation is the primary evolutionary driver of leaf dissection.

  20. Statistical temperature profile retrievals in clear-air using passive 118-GHz O2 observations

    NASA Technical Reports Server (NTRS)

    Gasiewski, A. J.; Johnson, J. T.

    1993-01-01

    The clean-air temperature profile accuracy yielded by a localized linear statistical retrieval operator applied to passive aircraft-based 118-GHz spectra is demonstrated. A comparison of the statistically and physically derived correlation coefficients of antenna temperature and kinetic temperature furnishes a physical justification of the statistical retrieval technique. The atmospheric temperature mean and covariance significantly depend on such geophysical parameters as latitude, longitude, local season, and time, as well as the prevailing meteorological state and orographic effects.

  1. An Air Temperature Cloud Height Precipitation Phase Determination Scheme for Surface Based Modeling

    NASA Astrophysics Data System (ADS)

    Feiccabrino, J. M.

    2015-12-01

    Many hydrological and ecological models use simple surface temperature threshold equations rather than coupling with a complex meteorological model to determine if precipitation is rain or snow. Some comparative studies have found, the most common rain/snow threshold variable, air temperature to have more precipitation phase error than dew-point or wet-bulb temperature, which account for the important secondary role of humidity in the melting and sublimation processes. However, just like surface air temperature, surface humidity is often effected by soil conditions and vegetation and is therefore not always representative of the atmospheric humidity precipitation falls through. A viable alternative to using surface humidity as a proxy for atmospheric moisture would be to adjust the rain snow threshold for changes in cloud height. The height of a cloud base above the ground gives the depth of an unsaturated layer. An unsaturated atmospheric layer should have much different melting and sublimation rates than a saturated cloud layer. Therefore, rain and snow percentages at a given surface air temperature should change with the height of the lowest cloud base. This study uses hourly observations from 12 U.S. manually augmented meteorological stations located in the Great Plains and Midwest upwind or away from major water bodies in relatively flat areas in an attempt to limit geographical influences. The surface air temperature threshold for the ground to 200 feet (under 100m) was 0.0°C, 0.6°C for 300-600 feet (100-200m), 1.1°C for 700-1200 feet (300-400m), 1.7°C for 1300-2000 feet (500-600m), and 2.2°C for 2100-3300 feet (700-1000m). Total precipitation error for these cloud height air temperature thresholds reduced the error from the single air temperature threshold 1.1°C by 15% from 14% to 12% total error between -2.2°C and 3.9°C. These air temperature cloud height thresholds resulted in 1.5% less total error than the dew-point temperature threshold 0.0

  2. Soybean grown under elevated CO2 benefits more under low temperature than high temperature stress: Varying response of photosynthetic limitations, leaf metabolites, growth, and seed yield.

    PubMed

    Xu, Guangli; Singh, Shardendu K; Reddy, Vangimalla R; Barnaby, Jinyoung Y; Sicher, Richard C; Li, Tian

    2016-10-20

    To evaluate the combined effect of temperature and CO2 on photosynthetic processes, leaf metabolites and growth, soybean was grown under a controlled environment at low (22/18°C, LT), optimum (28/24°C, OT) and high (36/32°C HT) temperatures under ambient (400μmolmol(-1); aCO2) or elevated (800μmolmol(-1); eCO2) CO2 concentrations during the reproductive stage. In general, the rate of photosynthesis (A), stomatal (gs) and mesophyll (gm) conductance, quantum yield of photosystem II, rates of maximum carboxylation (VCmax), and electron transport (J) increased with temperature across CO2 levels. However, compared with OT, the percentage increases in these parameters at HT were lower than the observed decline at LT. The photosynthetic limitation at LT and OT was primarily caused by photo-biochemical processes (49-58%, Lb) followed by stomatal (27-32%, Ls) and mesophyll (15-19%, Lm) limitations. However, at HT, it was primarily caused by Ls (41%) followed by Lb (33%) and Lm (26%). The dominance of Lb at LT and OT was associated with the accumulation of non-structural carbohydrates (e.g., starch) and several organic acids, whereas this accumulation did not occur at HT, indicating increased metabolic activities. Compared with OT, biomass and seed yield declined more at HT than at LT. The eCO2 treatment compensated for the temperature-stress effects on biomass but only partially compensated for the effects on seed yield, especially at HT. Photosynthetic downregulation at eCO2 was possibly due to the accumulation of non-structural carbohydrates and the decrease in gs and Astd (standard A measured at 400μmolmol(-1) sub-stomatal CO2 concentration), as well as the lack of CO2 effect on gm, VCmax, and J, and photosynthetic limitation. Thus, the photosynthetic limitation was temperature-dependent and was primarily influenced by the alteration in photo-biochemical processes and metabolic activities. Despite the inconsistent response of photosynthesis (or biomass accumulation

  3. Data Assimilation Experiments Using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains a number of significant improvements over Version 4. Two very significant improvements are described briefly below. 1) The AIRS Science Team Radiative Transfer Algorithm (RTA) has now been upgraded to accurately account for effects of non-local thermodynamic equilibrium on the AIRS observations. This allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval algorithm during both day and night. Following theoretical considerations, tropospheric temperature profile information is obtained almost exclusively from clear column radiances in the 4.3 micron CO2 band in the AIRS Version 5 temperature profile retrieval step. These clear column radiances are a derived product that are indicative of radiances AIRS channels would have seen if the field of view were completely clear. Clear column radiances for all channels are determined using tropospheric sounding 15 micron CO2 observations. This approach allows for the generation of accurate values of clear column radiances and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel clear column radiances. These error estimates are used for quality control of the retrieved products. Based on error estimate thresholds, each temperature profiles is assigned a characteristic pressure, pg, down to which the profile is characterized as good for use for data assimilation purposes. We have conducted forecast impact experiments assimilating AIRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the

  4. Two major volcanic cooling episodes derived from global marine air temperature, AD 1807-1827

    NASA Astrophysics Data System (ADS)

    Chenoweth, Michael

    A new data set of global marine air temperature data for the years 1807-1827 is used to show the impact of volcanic eruptions in ˜ 1809 (unlocated) and 1815 (Tambora, Indonesia). Both eruptions produced cooling exceeding that after Krakatoa, Indonesia (1883) and Pinatubo, Philippines (1991). The ˜1809 eruption is dated to March-June 1808 based on a sudden cooling in Malaysian temperature data and maximum cooling of marine air temperature in 1809. Two large-scale calibrated proxy temperature records, one from tree-ring-density data, the other using multi-proxy sources are compared to the marine air temperature data. Correlation is highest with maximum latewood density data and lowest with the multi-proxy data.

  5. 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.

  6. Air temperature distribution over a debris covered glacier in the Nepalese Himalayas

    NASA Astrophysics Data System (ADS)

    Pellicciotti, Francesca; Petersen, Lene; Wicki, Simon; Carenzo, Marco; Immerzeel, Walter

    2013-04-01

    Air temperature is a key control in the exchange of energy fluxes at the glacier-atmosphere interface and also the main input variable in many of the melt models (both energy balance or temperature-index type of models) currently used to predict glacier melt across a variety of scales. The commonly used approach to derive distributed temperature inputs is extrapolation from point measurements, often located outside the glacier surface, with a lapse rate that is assumed to be constant in time and uniform in space. Previous work for debris free glaciers has shown that lapse rates depend on several factors such as katabatic wind, humidity and the presence of clouds and that they vary in space and time. A dominant control however seems to be the presence of katabatic wind. For debris covered glaciers, the driving forces of air temperature are likely to be different but little is known because of the scarcity of field observations. Few preliminary studies have suggested that there is a strong coupling between surface and 2 m air temperature, while strong katabatic wind does not develop on debris covered tongues. In this study, we examine the variability in air temperature and lapse rates, as well as its atmospheric controls under different meteorological settings for the debris covered Lirung Glacier in the Nepalese Himalayas. We use a recently collected data set of air and surface temperature at a network of locations on the glacier tongue during the pre-monsoon season and the entire monsoon season of 2012. Additionally an AWS was installed on the glacier allowing the collection of meteorological observations. We investigate differences in air temperature during different climatic conditions (monsoon vs. dry period, upvalley vs. downvalley wind, cloudy vs. clear-sky, etc.). We identify the main controls on temperature and discuss how appropriate the application of a temperature lapse rate is over a debris covered glacier by investigating the correlation between

  7. Dependence of radon levels in Postojna Cave on outside air temperature

    NASA Astrophysics Data System (ADS)

    Gregorič, A.; Zidanšek, A.; Vaupotič, J.

    2011-05-01

    Postojna Cave is the largest of 21 show caves in Slovenia. The radon concentration there was measured continuously in the Great Mountain hall from July 2005 to October 2009 and ranged from about 200 Bq m-3 in winter to about 3 kBq m-3 in summer. The observed seasonal pattern of radon concentration is governed by air movement due to the difference in external and internal air densities, controlled mainly by air temperature. The cave behaves as a large chimney and in the cold period, the warmer cave air is released vertically through cracks and fissures to the colder outside atmosphere, enabling the inflow of fresh air with low radon levels. In summer the ventilation is minimal or reversed and the air flows from the higher to the lower openings of the cave. Our calculations have shown that the effect of the difference between outside and cave air temperatures on radon concentration is delayed for four days, presumably because of the distance of the measurement point from the lower entrance (ca. 2 km). A model developed for predicting radon concentration on the basis of outside air temperature has been checked and found to be successful.

  8. Application of high temperature air heaters to advanced power generation cycles

    SciTech Connect

    Thompson, T R; Boss, W H; Chapman, J N

    1992-03-01

    Recent developments in ceramic composite materials open up the possibility of recuperative air heaters heating air to temperatures well above the feasible with metal tubes. A high temperature air heater (HTAH) has long been recognized as a requirement for the most efficient MHD plants in order to reach high combustor flame temperatures. The application of gas turbines in coal-fired plants of all types has been impeded because of the problems in cleaning exhaust gas sufficiently to avoid damage to the turbine. With a possibility of a HTAH, such plants may become feasible on the basis of air turbine cycles, in which air is compressed and heated in the HTAH before being applied to turbine. The heat exchanger eliminates the need for the hot gas cleanup system. The performance improvement potential of advanced cycles with HTAH application including the air turbine cycle in several variations such as the DOE program on ``Coal-Fired Air Furnace Combined Cycle...,`` variations originated by the authors, and the MHD combined cycle are presented. The status of development of ceramic air heater technology is included.

  9. Characteristics of Gaseous Diffusion Flames with High Temperature Combustion Air in Microgravity

    NASA Technical Reports Server (NTRS)

    Ghaderi, M.; Gupta, A. K.

    2003-01-01

    The characteristics of gaseous diffusion flames have been obtained using high temperature combustion air under microgravity conditions. The time resolved flame images under free fall microgravity conditions were obtained from the video images obtained. The tests results reported here were conducted using propane as the fuel and about 1000 C combustion air. The burner included a 0.686 mm diameter central fuel jet injected into the surrounding high temperature combustion air. The fuel jet exit Reynolds number was 63. Several measurements were taken at different air preheats and fuel jet exit Reynolds number. The resulting hybrid color flame was found to be blue at the base of the flame followed by a yellow color flame. The length and width of flame during the entire free fall conditions has been examined. Also the relative flame length and width for blue and yellow portion of the flame has been examined under microgravity conditions. The results show that the flame length decreases and width increases with high air preheats in microgravity condition. In microgravity conditions the flame length is larger with normal temperature combustion air than high temperature air.

  10. Influence of intake air temperature on internal combustion engine operation

    NASA Astrophysics Data System (ADS)

    Birtok-Băneasă, C.; Raţiu, S.; Hepuţ, T.

    2017-01-01

    This paper presents three methods for reduce thermal losses in the intake system with improvement of airflow and thermal protection. In the experiment are involved two patented devices conceived by the author and one PhD theme device: 1- Dynamic device for air transfer, 2-Integrated thermal deflector, and, 3-Advanced thermal protection. The tests were carried on different vehicle running in real traffic and in the Internal Combustion Engines Laboratory, within the specialization “Road vehicle” belonging to the Faculty of Engineering Hunedoara, component of Politehnica University of Timişoara. The results have been processed and compared whit the ones obtained without these devices.

  11. Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels: The AIRS Version 6 Retrieval Algorithm

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John; Iredell, Lena

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002 together with ASMU-A and HSB to form a next generation polar orbiting infrared and microwave atmosphere sounding system (Pagano et al 2003). The theoretical approach used to analyze AIRS/AMSU/HSB data in the presence of clouds in the AIRS Science Team Version 3 at-launch algorithm, and that used in the Version 4 post-launch algorithm, have been published previously. Significant theoretical and practical improvements have been made in the analysis of AIRS/AMSU data since the Version 4 algorithm. Most of these have already been incorporated in the AIRS Science Team Version 5 algorithm (Susskind et al 2010), now being used operationally at the Goddard DISC. The AIRS Version 5 retrieval algorithm contains three significant improvements over Version 4. Improved physics in Version 5 allowed for use of AIRS clear column radiances (R(sub i)) in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations were used primarily in the generation of clear column radiances (R(sub i)) for all channels. This new approach allowed for the generation of accurate Quality Controlled values of R(sub i) and T(p) under more stressing cloud conditions. Secondly, Version 5 contained a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 contained for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Susskind et al 2010 shows that Version 5 AIRS Only sounding are only slightly degraded from the AIRS/AMSU soundings, even at large fractional cloud

  12. Apparatus and Method for Measuring Air Temperature Ahead of an Aircraft for Controlling a Variable Inlet/Engine Assembly

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    2001-01-01

    The apparatus and method employ remote sensing to measure the air temperature a sufficient distance ahead of the aircraft to allow time for a variable inlet/engine assembly to be reconfigured in response to the measured temperature, to avoid inlet unstart and/or engine compressor stall. In one embodiment, the apparatus of the invention has a remote sensor for measuring at least one air temperature ahead of the vehicle and an inlet control system for varying the inlet. The remote sensor determines a change in temperature value using at least one temperature measurement and prior temperature measurements corresponding to the location of the aircraft. The control system uses the change in air temperature value to vary the inlet configuration to maintain the position of the shock wave during the arrival of the measured air in the inlet. In one embodiment, the method of the invention includes measuring at least one air temperature ahead of the vehicle, determining an air temperature at the vehicle from prior air temperature measurements, determining a change in temperature value using the air temperature at the vehicle and the at least one air temperature measurement ahead of the vehicle, and using the change in temperature value to-reposition the airflow inlet, to cause the shock wave to maintain substantially the same position within the inlet as the airflow temperature changes within the inlet.

  13. Analysis of nocturnal air temperature in districts using mobile measurements and a cooling indicator

    NASA Astrophysics Data System (ADS)

    Leconte, François; Bouyer, Julien; Claverie, Rémy; Pétrissans, Mathieu

    2016-08-01

    The urban heat island phenomenon is generally defined as an air temperature difference between a city center and the non-urbanized rural areas nearby. However, this description does not encompass the intra-urban temperature differences that exist between neighborhoods in a city. This study investigates the air temperature dynamics of neighborhoods for meteorological conditions that lead to important urban heat island amplitude. Local climate zones (LCZs) have been determined in Nancy, France, and mobile screen-height air temperature measurements are performed using an instrumented vehicle. Initially, hourly measurements are performed within four different LCZs. These results show that air temperature within LCZ demonstrates a nocturnal cooling in two phases, i.e., a first phase between 1 to 3 h before sunset and 3 to 5 h after sunset, and a second phase from 3 to 5 h after sunset to sunrise. During phase 1, neighborhoods exhibit different cooling rate values and air temperature gaps develop between districts, while during phase 2, cooling rates tend to be analogous. Then, a larger meteorological data set is used to investigate these two phases for a selection of 13 LCZs. Normalized cooling rates are calculated between daytime measures and nighttime measures in order to quantify the air temperature dynamics of the studied areas during phase 1. Considering this indicator, three groups are emerging: LCZ compact midrise and open midrise with mean normalized cooling rate values of 0.09 h -1 LCZ large lowrise and open lowrise/sparsely built with mean normalized cooling rate values of 0.011 h -1 LCZ low plants with mean normalized cooling rate values of 0.014 h -1 Results indicate that the relative position of LCZ within the conurbation does not drive air temperature dynamics during phase 1. In addition, measures performed during phase 2 tend to illustrate that cooling rates are similar to all LCZ during this period.

  14. The relationship between radiant heat, air temperature and thermal comfort at rest and exercise.

    PubMed

    Guéritée, Julien; Tipton, Michael J

    2015-02-01

    The aims of the present work were to investigate the relationships between radiant heat load, air velocity and body temperatures with or without coincidental exercise to determine the physiological mechanisms that drive thermal comfort and thermoregulatory behaviour. Seven male volunteers wearing swimming trunks in 18°C, 22°C or 26°C air were exposed to increasing air velocities up to 3 m s(-1) and self-adjusted the intensity of the direct radiant heat received on the front of the body to just maintain overall thermal comfort, at rest or when cycling (60 W, 60 rpm). During the 30 min of the experiments, skin and rectal temperatures were continuously recorded. We hypothesized that mean body temperature should be maintained stable and the intensity of the radiant heat and the mean skin temperatures would be lower when cycling. In all conditions, mean body temperature was lower when facing winds of 3 m s(-1) than during the first 5 min, without wind. When facing winds, in all but the 26°C air, the radiant heat was statistically higher at rest than when exercising. In 26°C air mean skin temperature was lower at rest than when exercising. No other significant difference was observed. In all air temperatures, high correlation coefficients were observed between the air velocity and the radiant heat load. Other factors that we did not measure may have contributed to the constant overall thermal comfort status despite dropping mean skin and body temperatures. It is suggested that the allowance to behaviourally adjust the thermal environment increases the tolerance of cold discomfort.

  15. BOREAS RSS-17 Stem, Soil, and Air Temperature Data

    NASA Technical Reports Server (NTRS)

    Zimmerman, Reiner; McDonald, Kyle C.; Way, JoBea; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS RSS-17 team collected several data sets in support of its research in monitoring and analyzing environmental and phenological states using radar data. This data set consists of tree bole and soil temperature measurements from various BOREAS flux tower sites. Temperatures were measured with thermistors implanted in the hydroconductive tissue of the trunks of several trees at each site and at various depths in the soil. Data were stored on a data logger at intervals of either 1 or 2 hours. The majority of the data were acquired between early 1994 and early 1995. The primary product of this data set is the diurnal stem temperature measurements acquired for selected trees at five BOREAS tower sites. The data are provided in tabular ASCII format. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  16. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    SciTech Connect

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue Fang, Jing

    2015-10-15

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  17. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    NASA Astrophysics Data System (ADS)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue; Fang, Jing

    2015-10-01

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  18. 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…

  19. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    Johnson, R. K.

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  20. Estimation of daily mean air temperature from satellite derived radiometric data

    NASA Technical Reports Server (NTRS)

    Phinney, D.

    1976-01-01

    The Screwworm Eradication Data System (SEDS) at JSC utilizes satellite derived estimates of daily mean air temperature (DMAT) to monitor the effect of temperature on screwworm populations. The performance of the SEDS screwworm growth potential predictions depends in large part upon the accuracy of the DMAT estimates.

  1. [Verification of exhaled air temperature and heat flux in respiratory diseases as useful biomarker].

    PubMed

    Ito, Wataru; Chihara, Junichi

    2008-12-01

    Asthma, chronic obstructive pulmonary disease, and diffuse panbronchiolitis are syndromes associated with chronic airway inflammation. In the conventional definition of inflammation, local pyrexia at the site of inflammation should be observed. However, there are very few reports that have evaluated the "heat" in inflammatory respiratory diseases. We considered that the evaluation of allergic airway inflammation such as asthma might be possible by measuring the exhaled air temperature, and devised an original device that stabilizes the flow rate, which is a very important factor for the direct measurement of heat. Moreover, an expiratory heat flux meter, which can detect a change in air temperature more precisely and immediately, was also incorporated into our original device. As a result, we succeeded in the measurement and evaluation of the heat flux and air temperature in healthy subjects and asthmatic patients, and, further, the air temperature was straightforwardly evaluated by a portable spirometer including a temperature sensor. These findings suggest that the heat flux and temperature of exhaled air can be used to objectively monitor airway inflammation noninvasively, and assist in the diagnosis/monitoring of inflammatory respiratory diseases, including asthma.

  2. Effects of ambient room temperature on cold air cooling during laser hair removal.

    PubMed

    Ram, Ramin; Rosenbach, Alan

    2007-09-01

    Forced air cooling is a well-established technique that protects the epidermis during laser heating of deeper structures, thereby allowing for increased laser fluences. The goal of this prospective study was to identify whether an elevation in ambient room temperature influences the efficacy of forced air cooling. Skin surface temperatures were measured on 24 sites (12 subjects) during cold air exposure in examination rooms with ambient temperatures of 72 degrees F (22.2 degrees C) and 82 degrees F (27.8 degrees C), respectively. Before cooling, mean skin surface temperature was 9 degrees F (5 degrees C) higher in the warmer room (P < 0.01). Immediately after exposure to forced air cooling (within 1 s), the skin surface temperature remained considerably higher (10.75 degrees F, or 5.8 degrees C, P < 0.01) in the warmer room. We conclude that forced air cooling in a room with an ambient temperature of 82 degrees F (27.8 degrees C) is not as effective as in a room that is at 72 degrees F (22.2 degrees C).

  3. Natural and forced air temperature variability in the Labrador region of Canada during the past century

    NASA Astrophysics Data System (ADS)

    Way, Robert G.; Viau, Andre E.

    2015-08-01

    Evaluation of Labrador air temperatures over the past century (1881-2011) shows multi-scale climate variability and strong linkages with ocean-atmospheric modes of variability and external forcings. The Arctic Oscillation, Atlantic Multidecadal Oscillation, and El Nino Southern Oscillation are shown to be the dominant seasonal and interannual drivers of regional air temperature variability for most of the past century. Several global climate models show disagreement with observations on the rate of recent warming which suggests that models are currently unable to reproduce regional climate variability in Labrador air temperature. Using a combination of empirical statistical modeling and global climate models, we show that 33 % of the variability in annual Labrador air temperatures over the period 1881-2011 can be explained by natural factors alone; however, the inclusion of anthropogenic forcing increases the explained variance to 65 %. Rapid warming over the past 17 years is shown to be linked to both natural and anthropogenic factors with several anomalously warm years being primarily linked to recent anomalies in the Arctic Oscillation and North Atlantic sea surface temperatures. Evidence is also presented that both empirical statistical models and global climate models underestimate the regional air temperature response to ocean salinity anomalies and volcanic eruptions. These results provide important insight into the predictability of future regional climate impacts for the Labrador region.

  4. Prediction of air temperature for thermal comfort of people using sleeping bags: a review

    NASA Astrophysics Data System (ADS)

    Huang, Jianhua

    2008-11-01

    Six models for determining air temperatures for thermal comfort of people using sleeping bags were reviewed. These models were based on distinctive metabolic rates and mean skin temperatures. All model predictions of air temperatures are low when the insulation values of the sleeping bag are high. Nevertheless, prediction variations are greatest for the sleeping bags with high insulation values, and there is a high risk of hypothermia if an inappropriate sleeping bag is chosen for the intended conditions of use. There is, therefore, a pressing need to validate the models by wear trial and determine which one best reflects ordinary consumer needs.

  5. The temperature fields measurement of air in the car cabin by infrared camera

    NASA Astrophysics Data System (ADS)

    Pešek, M.

    2013-04-01

    The article deals with the temperature fields measurement of air using the Jenoptic Variocam infrared camera inside the car Škoda Octavia Combi II. The temperature fields with the use of auxiliary material with a high emissivity value were visualized. The measurements through the viewing window with a high transmissivity value were performed. The viewing windows on the side car door were placed. In the rear car area, the temperature fields of air on the spacious sheet of auxiliary material were visualized which is a suitable method for 2D airstreams. In the front car area, the temperature fields in the air were measured with the use of the measuring net which is suitable for 3D airstreams measuring.

  6. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  7. The upper explosion limit of lower alkanes and alkenes in air at elevated pressures and temperatures.

    PubMed

    Van den Schoor, F; Verplaetsen, F

    2006-01-16

    The upper explosion limit (UEL) of ethane-air, propane-air, n-butane-air, ethylene-air and propylene-air mixtures is determined experimentally at initial pressures up to 30 bar and temperatures up to 250 degrees C. The experiments are performed in a closed spherical vessel with an internal diameter of 200 mm. The mixtures are ignited by fusing a coiled tungsten wire, placed at the centre of the vessel, by electric current. Flame propagation is said to have taken place if there is a pressure rise of at least 1% of the initial pressure after ignition of the mixture. In the pressure-temperature range investigated, a linear dependence of UEL on temperature and a bilinear dependence on pressure are found except in the vicinity of the auto-ignition range. A comparison of the UEL data of the lower alkanes shows that the UEL expressed as equivalence ratio (the actual fuel/air ratio divided by the stoichiometric fuel/air ratio) increases with increasing carbon number in the homologous series of alkanes.

  8. Improving Forecast Skill by Assimilation of Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of cloud cleared radiances R(sub i). This approach allows for the generation of accurate values of R(sub i) and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel error estimates for R(sub i). These error estimates are used for Quality Control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of Quality Control using the NASA GEOS-5 data assimilation system. Assimilation of Quality Controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done operationally by ECMWF and NCEP. Forecast resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  9. Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    SUsskind, Joel

    2008-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 pm C02 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 pm C02 observations are now used primarily in the generation of cloud cleared radiances Ri. This approach allows for the generation of accurate values of Ri and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by- channel error estimates for Ri. These error estimates are used for quality control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of quality control using the NASA GEOS-5 data assimilation system. Assimilation of quality controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done Operationally by ECMWF and NCEP. Forecasts resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  10. Interactive short-term effects of equivalent temperature and air pollution on human mortality in Berlin and Lisbon.

    PubMed

    Burkart, Katrin; Canário, Paulo; Breitner, Susanne; Schneider, Alexandra; Scherber, Katharina; Andrade, Henrique; Alcoforado, Maria João; Endlicher, Wilfried

    2013-12-01

    There is substantial evidence that both temperature and air pollution are predictors of mortality. Thus far, few studies have focused on the potential interactive effects between the thermal environment and different measures of air pollution. Such interactions, however, are biologically plausible, as (extreme) temperature or increased air pollution might make individuals more susceptible to the effects of each respective predictor. This study investigated the interactive effects between equivalent temperature and air pollution (ozone and particulate matter) in Berlin (Germany) and Lisbon (Portugal) using different types of Poisson regression models. The findings suggest that interactive effects exist between air pollutants and equivalent temperature. Bivariate response surface models and generalised additive models (GAMs) including interaction terms showed an increased risk of mortality during periods of elevated equivalent temperatures and air pollution. Cold effects were mostly unaffected by air pollution. The study underscores the importance of air pollution control in mitigating heat effects.

  11. Fault diagnosis and temperature sensor recovery for an air-handling unit

    SciTech Connect

    Lee, W.Y.; Shin, D.R.; House, J.M.

    1997-12-31

    The presence of faults and the influence they have on system operation is a real concern in the heating, ventilating, and air-conditioning (HVAC) community. A fault can be defined as an inadmissible or unacceptable property of a system or a component. Unless corrected, faults can lead to increased energy use, shorter equipment life, and uncomfortable and/or unhealthy conditions for building occupants. This paper describes the use of a two-stage artificial neural network for fault diagnosis in a simulated air-handling unit. The stage one neural network is trained to identify the subsystem in which a fault occurs. The stage two neural network is trained to diagnose the specific cause of a fault at the subsystem level. Regression equations for the supply and mixed-air temperatures are obtained from simulation data and are used to compute input parameters to the neutral networks. Simulation results are presented that demonstrate that, after a successful diagnosis of a supply air temperature sensor fault, the recovered estimate of the supply air temperature obtained from the regression equation can be used in a feedback control loop to bring the supply air temperature back to the setpoint value. Results are also presented that illustrate the evolution of the diagnosis of the two-stage artificial neural network from normal operation to various fault modes of operation.

  12. An ultrasonic air temperature measurement system with self-correction function for humidity

    NASA Astrophysics Data System (ADS)

    Tsai, Wen-Yuan; Chen, Hsin-Chieh; Liao, Teh-Lu

    2005-02-01

    This paper proposes an ultrasonic measurement system for air temperature with high accuracy and instant response. It can measure the average temperature of the environmental air by detecting the changes of the speed of the ultrasound in the air. The changes of speed of sound are computed from combining variations of time-of-flight (TOF) from a binary frequency shift-keyed (BFSK) ultrasonic signal and phase shift from continuous waves [11]. In addition, another proposed technique for the ultrasonic air temperature measurement is the self-correction functionality within a highly humid environment. It utilizes a relative humidity/water vapour sensor and applies the theory of how sound speed changes in a humid environment. The proposed new ultrasonic air temperature measurement has the capability of self-correction for the environment variable of humidity. Especially under the operational environment with high fluctuations of various humidity levels, the proposed system can accurately self-correct the errors on the conventional ultrasonic thermometer caused by the changing density of the vapours in the air. Including the high humidity effect, a proof-of-concept experiment demonstrates that in dry air (relative humidity, RH = 10%) without humidity correction, it is accurate to ±0.4 °C from 0 °C to 80 °C, while in highly humid air (relative humidity, RH = 90%) with self-correction functionality, it is accurate to ±0.3 °C from 0 °C to 80 °C with 0.05% resolution and temperature changes are instantly reflected within 100 ms.

  13. Near infrared leaf reflectance modeling

    NASA Technical Reports Server (NTRS)

    Parrish, J. B.

    1985-01-01

    Near infrared leaf reflectance modeling using Fresnel's equation (Kumar and Silva, 1973) and Snell's Law successfully approximated the spectral curve for a 0.25-mm turgid oak leaf lying on a Halon background. Calculations were made for ten interfaces, air-wax, wax-cellulose, cellulose-water, cellulose-air, air-water, and their inverses. A water path of 0.5 mm yielded acceptable results, and it was found that assignment of more weight to those interfaces involving air versus water or cellulose, and less to those involving wax, decreased the standard deviation of the error for all wavelengths. Data suggest that the air-cell interface is not the only important contributor to the overall reflectance of a leaf. Results also argue against the assertion that the near infrared plateau is a function of cell structure within the leaf.

  14. Global circuit response to seasonal variations in global surface air temperature

    NASA Technical Reports Server (NTRS)

    Williams, Earle R.

    1994-01-01

    Comparisons are made between the seasonal behavior of the global electrical circuit and the surface air temperature for the Tropics and for the globe. Positive correlations between global circuit parameters and temperature are identified on both semiannual and annual timescales. Lightning is the global circuit quantity found most responsive to temperature, with a sensitivity of the order of 10% per 1 C. These findings lend further validity to the use of global circuit measurements as a diagnostic for global change.

  15. Identifying anthropogenic anomalies in air, surface and groundwater temperatures in Germany.

    PubMed

    Benz, Susanne A; Bayer, Peter; Blum, Philipp

    2017-04-15

    Human activity directly influences ambient air, surface and groundwater temperatures. The most prominent phenomenon is the urban heat island effect, which has been investigated particularly in large and densely populated cities. This study explores the anthropogenic impact on the thermal regime not only in selected urban areas, but on a countrywide scale for mean annual temperature datasets in Germany in three different compartments: measured surface air temperature, measured groundwater temperature, and satellite-derived land surface temperature. Taking nighttime lights as an indicator of rural areas, the anthropogenic heat intensity is introduced. It is applicable to each data set and provides the difference between measured local temperature and median rural background temperature. This concept is analogous to the well-established urban heat island intensity, but applicable to each measurement point or pixel of a large, even global, study area. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1km×1km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity, albeit the different compartments are partially influenced through unrelated processes; unlike land surface temperature and surface air temperature, groundwater temperatures are elevated in cultivated areas as well. At the surface of Germany, the highest anthropogenic heat intensity with 4.5K is found at an open-pit lignite mine near Jülich, followed by three large cities (Munich, Düsseldorf and Nuremberg) with annual mean anthropogenic heat intensities >4K. Overall, surface anthropogenic heat intensities >0K and

  16. Impact of Surface Air Temperature and Snow Cover Depth on the Upper Soil Temperature Variations in Russia

    NASA Astrophysics Data System (ADS)

    Sherstyukov, B. G.; Sherstyukov, A. B.; Groisman, P. Y.

    2008-12-01

    For the 1965-2004 period, data from all Russian meteorological stations with long-term soil temperature observations at depths 80, 160 and 320 cm were compiled and analyzed. It was found that the prevailing influence on soil temperature variations in the European part of Russia was surface air temperature and in the Asian part of Russia - snow cover depth. By preserving the heat accumulated in the warm season, an observed increase of the winter snow depth in the permafrost zone (cf., Bulygina et al. 2007) promotes annual soil temperature increase and therefore may foster the further permafrost degradation associated with ongoing regional warming. The impact of long-term changes in surface air temperatures on soil temperatures in the central regions of the permafrost zone is weak throughout the year. However, in the regions with intermittent permafrost, this impact is substantial. The impact of snow depth on soil temperatures is observed throughout the entire permafrost zone of Russia. Reference cited: Bulygina O.N., N.N. Korshunova, and V.N. Razuvaev, 2007: Variations in snow characteristics over the Russian territory in the recent decades. Transactions of RIHMI-WDC, 173, 41-46.

  17. Effect of green roofs on air temperature; measurement study of well-watered and dry conditions

    NASA Astrophysics Data System (ADS)

    Solcerova, Anna; van de Ven, Frans; Wang, Mengyu; van de Giesen, Nick

    2016-04-01

    Rapid urbanization and increasing number and duration of heat waves poses a need for understanding urban climate and ways to mitigate extremely high temperatures. One of repeatedly suggested and often investigated methods to moderate the so called urban heat island are green roofs. This study investigates several extensive green roofs in Utrecht (NL) and their effect on air temperature right above the roof surface. Air temperature was measured 15 and 30 cm above the roof surface and also in the substrate. We show that under normal condition is air above green roof, compared to white gravel roof, colder at night and warmer during day. This suggest that green roofs might help decrease air temperatures at night, when the urban heat island is strongest, but possibly contribute to high temperatures during daytime. We also measured situation when the green roofs wilted and dried out. Under such conditions green roof exhibits more similar behavior to conventional white gravel roof. Interestingly, pattern of soil temperature remains almost the same for both dry and well-prospering green roof, colder during day and warmer at night. As such, green roof works as a buffer of diurnal temperature changes.

  18. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity.

    PubMed

    Bugbee, B; Monje, O; Tanner, B

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  19. Ambient air pollution, temperature and out-of-hospital coronary deaths in Shanghai, China.

    PubMed

    Dai, Jinping; Chen, Renjie; Meng, Xia; Yang, Changyuan; Zhao, Zhuohui; Kan, Haidong

    2015-08-01

    Few studies have evaluated the effects of ambient air pollution and temperature in triggering out-of-hospital coronary deaths (OHCDs) in China. We evaluated the associations of air pollution and temperature with daily OHCDs in Shanghai, China from 2006 to 2011. We applied an over-dispersed generalized additive model and a distributed lag nonlinear model to analyze the effects of air pollution and temperature, respectively. A 10 μg/m(3) increase in the present-day PM10, PM2.5, SO2, NO2 and CO were associated with increases in OHCD mortality of 0.49%, 0.68%, 0.88%, 1.60% and 0.08%, respectively. A 1 °C decrease below the minimum-mortality temperature corresponded to a 3.81% increase in OHCD mortality on lags days 0-21, and a 1 °C increase above minimum-mortality temperature corresponded to a 4.61% increase over lag days 0-3. No effects were found for in-hospital coronary deaths. This analysis suggests that air pollution, low temperature and high temperature may increase the risk of OHCDs.

  20. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; Monje, O.; Tanner, B.

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  1. Influence of metallic vapours on thermodynamic and transport properties of two-temperature air plasma

    NASA Astrophysics Data System (ADS)

    Zhong, Linlin; Wang, Xiaohua; Cressault, Yann; Teulet, Philippe; Rong, Mingzhe

    2016-09-01

    The metallic vapours (i.e., copper, iron, and silver in this paper) resulting from walls and/or electrode surfaces can significantly affect the characteristics of air plasma. Different from the previous works assuming local thermodynamic equilibrium, this paper investigates the influence of metallic vapours on two-temperature (2 T) air plasma. The 2 T compositions of air contaminated by Cu, Fe, and Ag are first determined based on Saha's and Guldberg-Waage's laws. The thermodynamic properties (including mass density, specific enthalpy, and specific heat) are then calculated according to their definitions. After determining the collision integrals for each pair of species in air-metal mixtures using the newly published methods and source data, the transport coefficients (including electrical conductivity, viscosity, and thermal conductivity) are calculated for air-Cu, air-Fe, and air-Ag plasmas with different non-equilibrium degree θ (Te/Th). The influences of metallic contamination as well as non-equilibrium degree are discussed. It is found that copper, iron, and silver exist mainly in the form of Cu2, FeO, and AgO at low temperatures. Generally, the metallic vapours increase mass density at most temperatures, reduce the specific enthalpy and specific heat in the whole temperature range, and affect the transport properties remarkably from 5000 K to 20 000 K. The effect arising from the type of metals is little except for silver at certain temperatures. Besides, the departure from thermal equilibrium results in the delay of dissociation and ionization reactions, leading to the shift of thermodynamic and transport properties towards a higher temperature.

  2. Measuring centimeter-resolution air temperature profiles above land and water using fiber-optic Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Sigmund, Armin; Pfister, Lena; Olesch, Johannes; Thomas, Christoph K.

    2016-04-01

    The precise determination of near-surface air temperature profiles is of special importance for the characterization of airflows (e.g. cold air) and the quantification of sensible heat fluxes according to the flux-gradient similarity approach. In contrast to conventional multi-sensor techniques, measuring temperature profiles using fiber-optic Distributed Temperature Sensing (DTS) provides thousands of measurements referenced to a single calibration standard at much reduced costs. The aim of this work was to enhance the vertical resolution of Raman scatter DTS measurements up to the centimeter-scale using a novel approach for atmospheric applications: the optical fiber was helically coiled around a meshed fabric. In addition to testing the new fiber geometry, we quantified the measurement uncertainty and demonstrated the benefits of the enhanced-resolution profiles. The fiber-optic cable was coiled around a hollow column consisting of white reinforcing fabric supported by plexiglass rings every meter. Data from two columns of this type were collected for 47 days to measure air temperature vertically over 3.0 and 5.1 m over a gently inclined meadow and over and in a small lake, respectively. Both profiles had a vertical resolution of 1 cm in the lower section near the surface and 5 cm in the upper section with an along-fiber instrument-specific averaging of 1.0 m and a temporal resolution of 30 s. Measurement uncertainties, especially from conduction between reinforcing fabric and fiber-optic cable, were estimated by modeling the fiber temperature via a detailed energy balance approach. Air temperature, wind velocity and radiation components were needed as input data and measured separately. The temperature profiles revealed valuable details, especially in the lowest 1 m above surface. This was best demonstrated for nighttime observations when artefacts due to solar heating did not occur. For example, the dynamics of a cold air layer was detected in a clear night

  3. A photosynthesis-based two-leaf canopy stomatal conductance model for meteorology and air quality modeling with WRF/CMAQ PX LSM

    NASA Astrophysics Data System (ADS)

    Ran, Limei; Pleim, Jonathan; Song, Conghe; Band, Larry; Walker, John T.; Binkowski, Francis S.

    2017-02-01

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorology and air quality modeling system - WRF/CMAQ (Weather Research and Forecast model and Community Multiscale Air Quality model). The photosynthesis-based model for PX LSM (PX PSN) is evaluated at a FLUXNET site for implementation against different parameterizations and the current PX LSM approach with a simple Jarvis function (PX Jarvis). Latent heat flux (LH) from PX PSN is further evaluated at five FLUXNET sites with different vegetation types and landscape characteristics. Simulated ozone deposition and flux from PX PSN are evaluated at one of the sites with ozone flux measurements. Overall, the PX PSN simulates LH as well as the PX Jarvis approach. The PX PSN, however, shows distinct advantages over the PX Jarvis approach for grassland that likely result from its treatment of C3 and C4 plants for CO2 assimilation. Simulations using Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) rather than LAI measured at each site assess how the model would perform with grid averaged data used in WRF/CMAQ. MODIS LAI estimates degrade model performance at all sites but one site having exceptionally old and tall trees. Ozone deposition velocity and ozone flux along with LH are simulated especially well by the PX PSN compared to significant overestimation by the PX Jarvis for a grassland site.

  4. Assimilation of Quality Controlled AIRS Temperature Profiles using the NCEP GFS

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste; Iredell, Lena; Rosenberg, Robert

    2013-01-01

    We have previously conducted a number of data assimilation experiments using AIRS Version-5 quality controlled temperature profiles as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The data assimilation and forecast system we used was the Goddard Earth Observing System Model , Version-5 (GEOS-5) Data Assimilation System (DAS), which represents a combination of the NASA GEOS-5 forecast model with the National Centers for Environmental Prediction (NCEP) operational Grid Point Statistical Interpolation (GSI) global analysis scheme. All analyses and forecasts were run at a 0.5deg x 0.625deg spatial resolution. Data assimilation experiments were conducted in four different seasons, each in a different year. Three different sets of data assimilation experiments were run during each time period: Control; AIRS T(p); and AIRS Radiance. In the "Control" analysis, all the data used operationally by NCEP was assimilated, but no AIRS data was assimilated. Radiances from the Aqua AMSU-A instrument were also assimilated operationally by NCEP and are included in the "Control". The AIRS Radiance assimilation adds AIRS observed radiance observations for a select set of channels to the data set being assimilated, as done operationally by NCEP. In the AIRS T(p) assimilation, all information used in the Control was assimilated as well as Quality Controlled AIRS Version-5 temperature profiles, i.e., AIRS T(p) information was substituted for AIRS radiance information. The AIRS Version-5 temperature profiles were presented to the GSI analysis as rawinsonde profiles, assimilated down to a case-by-case appropriate pressure level p(sub best) determined using the Quality Control procedure. Version-5 also determines case-by-case, level-by-level error estimates of the temperature profiles, which were used as the uncertainty of each temperature measurement. These experiments using GEOS-5 have shown that forecasts

  5. The influence of snow depth and surface air temperature on satellite-derived microwave brightness temperature. [central Russian steppes, and high plains of Montana, North Dakota, and Canada

    NASA Technical Reports Server (NTRS)

    Foster, J. L.; Hall, D. K.; Chang, A. T. C.; Rango, A.; Allison, L. J.; Diesen, B. C., III

    1980-01-01

    Areas of the steppes of central Russia, the high plains of Montana and North Dakota, and the high plains of Canada were studied in an effort to determine the relationship between passive microwave satellite brightness temperature, surface air temperature, and snow depth. Significant regression relationships were developed in each of these homogeneous areas. Results show that sq R values obtained for air temperature versus snow depth and the ratio of microwave brightness temperature and air temperature versus snow depth were not as the sq R values obtained by simply plotting microwave brightness temperature versus snow depth. Multiple regression analysis provided only marginal improvement over the results obtained by using simple linear regression.

  6. Quantitative reconstruction of paleoclimate - Air and ground temperature tracking from Emigrant Pass Observatory

    NASA Astrophysics Data System (ADS)

    Chapman, D. S.; Bartlett, M. G.; Harris, R. N.

    2004-12-01

    Borehole temperature-depth profiles contain information about surface ground temperatures histories and provide a useful complement to proxy indicators of climate change. An inherent assumption in borehole temperature reconstructions is that air and ground temperatures are coupled through heat diffusion track each other at annual and longer periods. The Emigrant Pass Observatory (EPO), located in the Grouse Creek Mountains of northwestern Utah, is designed to test ground-air temperature tracking. Analyses of 10 years of observations at EPO demonstrate the following: 1) Ground temperatures track air temperatures at annual and longer periods exceptionally well at the site. Divergence between the observed temperatures at 1 m in the subsurface and air temperatures modeled as a boundary layer forcing is less than 0.04 K per annum. 2) Seasonal variations in incident solar radiation are ~200 Wm-2 leading to an average annual difference between ground and air temperatures, Δ Tg-a, of 2.55 K (±0.01) from 1993-2003. The temperature difference varies from -5 K to +10 K when averaged over a diurnal cycle, and from 2.50 K to 2.60 K over an annual cycle. However, inter-annual variations in insulation are less than 1 Wm-2; consequently, solar radiation is not observed to affect the inter-annual tracking at the site. 3) Model studies snow-ground thermal interactions at EPO demonstrate that seasonal snow cover can either warm or cool the ground relative to the annual mean air temperature and that the winter snow effect is an order of magnitude smaller than the summer radiation effect at the site. 4) Temperature observations at various depths within the granite and soils at the site allow us to make estimates of in-situ thermal diffusivity and its changes with time. The "apparent" thermal diffusivity of the upper meter of granite at EPO ranges from 0.88-0.98 x 10-6 m2s-1 while the soil varies from 0.57-0.68 x 10-6 m2s-1. The accumulation of data at EPO leads to a quantitative

  7. Opportunities to Reduce Air-Conditioning Loads Through Lower Cabin Soak Temperatures

    SciTech Connect

    Farrington, R.; Cuddy, M.; Keyser, M.; Rugh, J.

    1999-07-12

    Air-conditioning loads can significantly reduce electric vehicle (EV) range and hybrid electric vehicle (HEV) fuel economy. In addition, a new U. S. emissions procedure, called the Supplemental Federal Test Procedure (SFTP), has provided the motivation for reducing the size of vehicle air-conditioning systems in the United States. The SFTP will measure tailpipe emissions with the air-conditioning system operating. If the size of the air-conditioning system is reduced, the cabin soak temperature must also be reduced, with no penalty in terms of passenger thermal comfort. This paper presents the impact of air-conditioning on EV range and HEV fuel economy, and compares the effectiveness of advanced glazing and cabin ventilation. Experimental and modeled results are presented.

  8. Air conditioner operation behaviour based on students' skin temperature in a classroom.

    PubMed

    Song, Gook-Sup; Lim, Jae-Han; Ahn, Tae-Kyung

    2012-01-01

    A total of 25 college students participated in a study to determine when they would use an air conditioner during a lecture in a university classroom. The ambient temperature and relative humidity were measured 75 cm above the floor every minute. Skin temperatures were measured every minute at seven points, according to the recommendation of Hardy and Dubois. The average clothing insulation value (CLO) of subjects was 0.53 ± 0.07 CLO. The mean air velocity in the classroom was 0.13 ± 0.028 m/s. When the subjects turned the air conditioner both on and off, the average ambient temperatures, relative humidity and mean skin temperatures were 27.4 and 23.7 °C (p = 0.000), 40.9 and 40.0% (p = 0.528) and 32.7 and 32.2 °C (p = 0.024), respectively. When the status of the air conditioner was changed, the differences of skin temperatures in core body parts (head, abdomen and thigh) were not statistically significant. However, in the extremities (mid-lower arm, hand, shin and instep), the differences were statistically significant. Subjects preferred a fluctuating environment to a constant temperature condition. We found that a changing environment does not affect classroom study.

  9. The comparative performance of an aviation engine at normal and high inlet air temperatures

    NASA Technical Reports Server (NTRS)

    Gardiner, Arthur W; Schey, Oscar W

    1928-01-01

    This report presents some results obtained during an investigation to determine the effect of high inlet air temperature on the performance of a Liberty 12 aviation engine. The purpose of this investigation was to ascertain, for normal service carburetor adjustments and a fixed ignition advance, the relation between power and temperature for the range of carburetor air temperatures that may be encountered when supercharging to sea level pressure at altitudes of over 20,000 feet and without intercooling when using plain aviation gasoline and mixtures of benzol and gasoline. The results show that for the conditions of test, both the brake and indicated power decrease with increase in air temperature at a faster rate than given by the theoretical assumption that power varies inversely as the square root of the absolute temperature. On a brake basis, the order of the difference in power for a temperature difference of 120 degrees F. Is 3 to 5 per cent. The observed relation between power and temperature when using the 30-70 blend was found to be linear. But, although these differences are noted, the above theoretical assumption may be considered as generally applicable except where greater precision over a wide range of temperatures is desired, in which case it appears necessary to test the particular engine under the given conditions. (author)

  10. Short-term effects of air temperature on mortality and effect modification by air pollution in three cities of Bavaria, Germany: A time-series analysis

    EPA Science Inventory

    Background: Air temperature has been shown to be associated with mortality; however, only very few studies have been conducted in Germany. This study examined the association between daily air temperature and cause-specific mortality in Bavaria, Southern Germany. Moreover, we inv...

  11. Prediction of air temperature for thermal comfort of people in outdoor environments

    NASA Astrophysics Data System (ADS)

    Huang, Jianhua

    2007-05-01

    Current thermal comfort indices do not take into account the effects of wind and body movement on the thermal resistance and vapor resistance of clothing. This may cause public health problem, e.g. cold-related mortality. Based on the energy balance equation and heat exchanges between a clothed body and the outdoor environment, a mathematical model was developed to determine the air temperature at which an average adult, wearing a specific outdoor clothing and engaging in a given activity, attains thermal comfort under outdoor environment condition. The results indicated low clothing insulation, less physical activity and high wind speed lead to high air temperature prediction for thermal comfort. More accurate air temperature prediction is able to prevent wearers from hypothermia under cold conditions.

  12. Local air temperature tolerance: a sensible basis for estimating climate variability

    NASA Astrophysics Data System (ADS)

    Kärner, Olavi; Post, Piia

    2016-11-01

    The customary representation of climate using sample moments is generally biased due to the noticeably nonstationary behaviour of many climate series. In this study, we introduce a moment-free climate representation based on a statistical model fitted to a long-term daily air temperature anomaly series. This model allows us to separate the climate and weather scale variability in the series. As a result, the climate scale can be characterized using the mean annual cycle of series and local air temperature tolerance, where the latter is computed using the fitted model. The representation of weather scale variability is specified using the frequency and the range of outliers based on the tolerance. The scheme is illustrated using five long-term air temperature records observed by different European meteorological stations.

  13. The effect of air temperature on the sappan wood extract drying

    NASA Astrophysics Data System (ADS)

    Djaeni, M.; Triyastuti, M. S.; Asiah, N.; Annisa, A. N.; Novita, D. A.

    2015-12-01

    The sappan wood extract contain natural colour called brazilin that can be used as a food colouring and antioxidant. The product is commonly found as a dry extract powder for consummer convenience. The spray dryer with air dehumidification can be an option to retain the colour and antioxidant agent. This paper discusses the effect of air temperature on sappan wood extract drying that was mixed with maltodextrin. As responses, the particle size, final moisture content, and extract solubility degradation were observed. In all cases, the process conducted in temperature ranging 90 - 110°C can retain the brazilin quality as seen in solubility and particle size. In addition, the sappan wood extract can be fully dried with moisture content below 2%. Moreover, with the increase of air temperature, the particle size of dry extract can be smaller.

  14. [Environment of high temperature or air particle matter pollution, and health promotion of exercise].

    PubMed

    Zhao, Jie-xiu; Xu, Min-xiao; Wu, Zhao-zhao

    2014-10-01

    It is important to keep human health in special environment, since the special environment has different effects on health. In this review, we focused on high temperature and air particle matter environment, and health promotion of exercise. Exercise and high temperature are the main non-pharmacological therapeutic interventions of insulin resistance (IR). PGC-1α is key regulatory factor in health promotion of exercise and high temperature. The novel hormone Irisin might be the important pathway through which heat and exercise could have positive function on IR. Air particle matter (PM) is associated with onset of many respiratory diseases and negative effects of exerciser performance. However, regular exercise plays an important role in improving health of respiratory system and lowering the risk induced by PM. Furthermore, free radicals and inflammatory pathways are included in the possible mechanisms of positive physiological effects induced by exercise in air particle matter environment.

  15. Design and Development of an air-cooled Temperature-Swing Adsorption Compressor for Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Mulloth, Lila M.

    2003-01-01

    The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no wearing parts. This paper discusses the design features of a TSAC hardware that uses air as the cooling medium and has Space Station application.

  16. Thermodynamic and Transport Properties of Real Air Plasma in Wide Range of Temperature and Pressure

    NASA Astrophysics Data System (ADS)

    Wang, Chunlin; Wu, Yi; Chen, Zhexin; Yang, Fei; Feng, Ying; Rong, Mingzhe; Zhang, Hantian

    2016-07-01

    Air plasma has been widely applied in industrial manufacture. In this paper, both dry and humid air plasmas' thermodynamic and transport properties are calculated in temperature 300-100000 K and pressure 0.1-100 atm. To build a more precise model of real air plasma, over 70 species are considered for composition. Two different methods, the Gibbs free energy minimization method and the mass action law method, are used to determinate the composition of the air plasma in a different temperature range. For the transport coefficients, the simplified Chapman-Enskog method developed by Devoto has been applied using the most recent collision integrals. It is found that the presence of CO2 has almost no effect on the properties of air plasma. The influence of H2O can be ignored except in low pressure air plasma, in which the saturated vapor pressure is relatively high. The results will serve as credible inputs for computational simulation of air plasma. supported by the National Key Basic Research Program of China (973 Program)(No. 2015CB251002), National Natural Science Foundation of China (Nos. 51521065, 51577145), the Science and Technology Project Funds of the Grid State Corporation (SGTYHT/13-JS-177), the Fundamental Research Funds for the Central Universities, and State Grid Corporation Project (GY71-14-004)

  17. Exploration of health risks related to air pollution and temperature in three Latin American cities.

    PubMed

    Romero-Lankao, Patricia; Qin, Hua; Borbor-Cordova, Mercy

    2013-04-01

    This paper explores whether the health risks related to air pollution and temperature extremes are spatially and socioeconomically differentiated within three Latin American cities: Bogota, Colombia, Mexico City, Mexico, and Santiago, Chile. Based on a theoretical review of three relevant approaches to risk analysis (risk society, environmental justice, and urban vulnerability as impact), we hypothesize that health risks from exposure to air pollution and temperature in these cities do not necessarily depend on socio-economic inequalities. To test this hypothesis, we gathered, validated, and analyzed temperature, air pollution, mortality and socioeconomic vulnerability data from the three study cities. Our results show the association between air pollution levels and socioeconomic vulnerabilities did not always correlate within the study cities. Furthermore, the spatial differences in socioeconomic vulnerabilities within cities do not necessarily correspond with the spatial distribution of health impacts. The present study improves our understanding of the multifaceted nature of health risks and vulnerabilities associated with global environmental change. The findings suggest that health risks from atmospheric conditions and pollutants exist without boundaries or social distinctions, even exhibiting characteristics of a boomerang effect (i.e., affecting rich and poor alike) on a smaller scale such as areas within urban regions. We used human mortality, a severe impact, to measure health risks from air pollution and extreme temperatures. Public health data of better quality (e.g., morbidity, hospital visits) are needed for future research to advance our understanding of the nature of health risks related to climate hazards.

  18. Exploration of health risks related to air pollution and temperature in three Latin American cities

    NASA Astrophysics Data System (ADS)

    Romero-Lankao, P.; Borbor Cordova, M.; Qin, H.

    2013-12-01

    We explore whether the health risks related to air pollution and temperature extremes are spatially and socioeconomically differentiated within three Latin American cities: Bogota, Colombia, Mexico City, Mexico, and Santiago, Chile. Based on a theoretical review of three relevant approaches to risk analysis (risk society, environmental justice, and urban vulnerability as impact), we hypothesize that health risks from exposure to air pollution and temperature in these cities do not necessarily depend on socio-economic inequalities. To test this hypothesis, we gathered, validated, and analyzed temperature, air pollution, mortality and socioeconomic vulnerability data from the three study cities. Our results show the association between air pollution levels and socioeconomic vulnerabilities did not always correlate within the study cities. Furthermore, the spatial differences in socioeconomic vulnerabilities within cities do not necessarily correspond with the spatial distribution of health impacts. The present study improves our understanding of the multifaceted nature of health risks and vulnerabilities associated with global environmental change. The findings suggest that health risks from atmospheric conditions and pollutants exist without boundaries or social distinctions, even exhibiting characteristics of a boomerang effect (i.e., affecting rich and poor alike) on a smaller scale such as areas within urban regions. We used human mortality, a severe impact, to measure health risks from air pollution and extreme temperatures. Public health data of better quality (e.g., morbidity, hospital visits) are needed for future research to advance our understanding of the nature of health risks related to climate hazards.

  19. Impact of aerosol on air temperature in Kuwait

    NASA Astrophysics Data System (ADS)

    Sabbah, I.

    2010-08-01

    This work uses MODIS aerosol optical thickness (AOT) data observed over Kuwait during the 7-year interval 2000-2007. The values of AOT and the Ångström wavelength exponent ( α) show a clear annual cycle. These data are categorized into two catalogues in terms of the values of the AOT of the 870 nm channel ( τ870). One catalogue (71 days) includes days with high values of AOT ( τ870 ≥ 0.75). The most probable "modal" value of α for these days is 0.52. The other catalogue (1162 days) consists of the background days with a modal value ~ 1.1 for the exponent α. This analysis is extended to include water vapor content (WVC), surface wind speed (V), visibility (Vis) and the diurnal temperature range (DTR). Chree's method of superposed-epoch analysis is applied to these parameters in order to compare the variation in the daily averages during days with high AOT values with respect to background days. The high values of AOT during the 71 days are positively correlated with aerosol size, near-surface winds and poor visibility. This concludes that the aerosol particles during these days were mostly dust. The mean daily value of the DTR (Δ T) and visibility reduced significantly during these days. This reduction on DTR is a direct result of increasing the atmospheric opacity due to the presence of dust.

  20. 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

  1. CO2 CH4 flux Air temperature Soil temperature and Soil moisture, Barrow, Alaska 2013 ver. 1

    DOE Data Explorer

    Margaret Torn

    2015-01-14

    This dataset consists of field measurements of CO2 and CH4 flux, as well as soil properties made during 2013 in Areas A-D of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Included are i) measurements of CO2 and CH4 flux made from June to September (ii) Calculation of corresponding Gross Primary Productivity (GPP) and CH4 exchange (transparent minus opaque) between atmosphere and the ecosystem (ii) Measurements of Los Gatos Research (LGR) chamber air temperature made from June to September (ii) measurements of surface layer depth, type of surface layer, soil temperature and soil moisture from June to September.

  2. Temperature measurements behind reflected shock waves in air. [radiometric measurement of gas temperature in self-absorbing gas flow

    NASA Technical Reports Server (NTRS)

    Bader, J. B.; Nerem, R. M.; Dann, J. B.; Culp, M. A.

    1972-01-01

    A radiometric method for the measurement of gas temperature in self-absorbing gases has been applied in the study of shock tube generated flows. This method involves making two absolute intensity measurements at identical wavelengths, but for two different pathlengths in the same gas sample. Experimental results are presented for reflected shock waves in air at conditions corresponding to incident shock velocities from 7 to 10 km/s and an initial driven tube pressure of 1 torr. These results indicate that, with this technique, temperature measurements with an accuracy of + or - 5 percent can be carried out. The results also suggest certain facility related problems.

  3. Independent support for leaf homeothermy during carbon uptake and the implications for the interpretation of tree-ring oxygen isotopes

    NASA Astrophysics Data System (ADS)

    Helliker, B. R.; Baldocchi, D. D.; Desai, A. R.; Goulden, M. L.; Davis, K. J.; Wofsy, S. C.; Munger, J. W.

    2010-12-01

    Tree rings provide an annual record of plant responses to climatic variability and the oxygen isotope ratio of tree-ring cellulose is thought to provide a record of leaf-to-air vapor pressure deficit. We recently developed a method to resolve tree-canopy leaf temperature when most carbon uptake occurs by using the oxygen isotope ratio of tree-ring cellulose and ambient relative humidity. We found a remarkably constant leaf temperature of 21.4 ± 2.2 °C in 39 tree species across 50° of latitude. There are two general mechanisms for this perceived leaf temperature homeostasis: (i) leaf temperature equals ambient air temperature and most photosynthesis occurs when ambient temperatures are near 21 °C. (ii) When carbon assimilation is maximal, the physiological and morphological properties of tree leaves and branches serve to maintain canopy leaf temperatures near 21 °C. To address these questions we calculated a temperature-weighted value for daytime net ecosystem exchange during the growing season for several biomes from published eddy covariance data. The results support the observation of a photosynthesis-weighted temperature near 21 °C determined through our isotope analysis. The results suggest that the controlling mechanism is likely a combination of points (i) and (ii) above. Further, these characteristics of tree ecophysiology must be considered when interpreting evaporative signals contained in tree ring oxygen isotopes- particularly those at high latitudes/altitudes.

  4. Estimating daily air temperatures over the Tibetan Plateau by dynamically integrating MODIS LST data

    NASA Astrophysics Data System (ADS)

    Zhang, Hongbo; Zhang, Fan; Ye, Ming; Che, Tao; Zhang, Guoqing

    2016-10-01

    Recently, remotely sensed land surface temperature (LST) data have been used to estimate air temperatures because of the sparseness of station measurements in remote mountainous areas. Due to the availability and accuracy of Moderate Resolution Imaging Spectroradiometer (MODIS) LST data, the use of a single term or a fixed combination of terms (e.g., Terra/Aqua night and Terra/Aqua day), as used in previous estimation methods, provides only limited practical application. Furthermore, the estimation accuracy may be affected by different combinations and variable data quality among the MODIS LST terms and models. This study presents a method that dynamically integrates the available LST terms to estimate the daily mean air temperature and simultaneously considers model selection, data quality, and estimation accuracy. The results indicate that the differences in model performance are related to the combinations of LST terms and their data quality. The spatially averaged cloud cover of 14% for the developed product between 2003 and 2010 is much lower than the 35-54% for single LST terms. The average cross-validation root-mean-square difference values are approximately 2°C. This study identifies the best LST combinations and statistical models and provides an efficient method for daily air temperature estimation with low cloud blockage over the Tibetan Plateau (TP). The developed data set and the method proposed in this study can help alleviate the problem of sparse air temperature data over the TP.

  5. Development of a high-temperature air-blown gasification system.

    PubMed

    Pian, C C; Yoshikawa, K

    2001-09-01

    Current status of high-temperature air-blown gasification technology development is reviewed. This advanced gasification system utilizes preheated air to convert coal and waste-derived fuels into synthetic fuel gas and value-added byproducts. A series of demonstrated, independent technologies are combined to form the core of this gasification system. A high-temperature, rapid devolatilization process is used to enhance the volatile yields from the fuel and to improve the gasification efficiency. A high-temperature pebble bed filter is used to remove to the slag and particulates from the synthetic fuel gas. Finally, a novel regenerative heater is used to supply the high-temperature air for the gasifier. Component development tests have shown that higher gasification efficiencies can be obtained at more fuel-rich operating conditions when high-temperature air is used as the gasification agent. Test results also demonstrated the flex-fuel capabilities of the gasifier design. Potential uses of this technology range from large-scale integrated gasification power plants to small-scale waste-to-energy applications.

  6. 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.

  7. Global Distribution and Variability of Surface Skin and Surface Air Temperatures as Depicted in the AIRS Version-6 Data Set

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Lee, Jae N.; Iredell, Lena

    2014-01-01

    In this presentation, we will briefly describe the significant improvements made in the AIRS Version-6 retrieval algorithm, especially as to how they affect retrieved surface skin and surface air temperatures. The global distribution of seasonal 1:30 AM and 1:30 PM local time 12 year climatologies of Ts,a will be presented for the first time. We will also present the spatial distribution of short term 12 year anomaly trends of Ts,a at 1:30 AM and 1:30 PM, as well as the spatial distribution of temporal correlations of Ts,a with the El Nino Index. It will be shown that there are significant differences between the behavior of 1:30 AM and 1:30 PM Ts,a anomalies in some arid land areas.

  8. Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

    NASA Astrophysics Data System (ADS)

    Gladden, H. J.; Liebert, C. H.

    1980-02-01

    The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

  9. Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

    NASA Technical Reports Server (NTRS)

    Gladden, H. J.; Liebert, C. H.

    1980-01-01

    The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

  10. An Experimental Investigation Into the Temperature Profile of a Compliant Foil Air Bearing

    NASA Technical Reports Server (NTRS)

    Radil, Kevin; Zeszotek, Michelle

    2004-01-01

    A series of tests was performed to determine the internal temperature profile in a compliant bump-type foil journal air bearing operating at room temperature under various speeds and load conditions. The temperature profile was collected by instrumenting a foil bearing with nine, type K thermocouples arranged in the center and along the bearing s edges in order to measure local temperatures and estimate thermal gradients in the axial and circumferential directions. To facilitate the measurement of maximum temperatures from viscous shearing in the air film, the thermocouples were tack welded to the backside of the bumps that were in direct contact with the top foil. The mating journal was coated with a high temperature solid lubricant that, together with the bearing, underwent high temperature start-stop cycles to produce a smooth, steady-state run-in surface. Tests were conducted at speeds from 20 to 50 krpm and loads ranging from 9 to 222 N. The results indicate that, over the conditions tested, both journal rotational speed and radial load are responsible for heat generation with speed playing a more significant role in the magnitude of the temperatures. The temperature distribution was nearly symmetric about the bearing center at 20 and 30 krpm but became slightly skewed toward one side at 40 and 50 krpm. Surprisingly, the maximum temperatures did not occur at the bearing edge where the minimum film thickness is expected but rather in the middle of the bearing where analytical investigations have predicted the air film to be much thicker. Thermal gradients were common during testing and were strongest in the axial direction from the middle of the bearing to its edges, reaching 3.78 8C/mm. The temperature profile indicated the circumferential thermal gradients were negligible.

  11. Retrieval of surface temperature by remote sensing. [of earth surface using brightness temperature of air pollutants

    NASA Technical Reports Server (NTRS)

    Gupta, S. K.; Tiwari, S. N.

    1976-01-01

    A simple procedure and computer program were developed for retrieving the surface temperature from the measurement of upwelling infrared radiance in a single spectral region in the atmosphere. The program evaluates the total upwelling radiance at any altitude in the region of the CO fundamental band (2070-2220 1/cm) for several values of surface temperature. Actual surface temperature is inferred by interpolation of the measured upwelling radiance between the computed values of radiance for the same altitude. Sensitivity calculations were made to determine the effect of uncertainty in various surface, atmospheric and experimental parameters on the inferred value of surface temperature. It is found that the uncertainties in water vapor concentration and surface emittance are the most important factors affecting the accuracy of the inferred value of surface temperature.

  12. SIRS: An Experiment to Measure the Free Air Temperature from a Satellite.

    PubMed

    Wark, D Q

    1970-08-01

    The Satellite Infrared Spectrometer (SIRS) on the Nimbus III satellite was designed to measure the earth's spectral radiances in the 15-microm band of carbon dioxide. From simultaneous measurements of spectral radiances it is possible to obtain the vertical temperature profile of the atmosphere. The measurements are approximated by the integral equation of radiative transfer, modified by one or two layers of clouds. A solution requires that the surface radiative temperature and the surface air temperature be known. By iteration, a solution based upon the statistical behavior of the atmosphere is obtained for the free air temperature and the cloud heights and amounts. Examples are presented, comparing the SIRS soundings with coincident radiosonde soundings. The results from this experiment indicate that the technique can be applied as a routine observing tool for meteorological use.

  13. A new approach for highly resolved air temperature measurements in urban areas

    NASA Astrophysics Data System (ADS)

    Buttstädt, M.; Sachsen, T.; Ketzler, G.; Merbitz, H.; Schneider, C.

    2011-02-01

    In different fields of applied local climate investigation, highly resolved data of air temperature are of great importance. As a part of the research programme entitled City2020+, which deals with future climate conditions in agglomerations, this study focuses on increasing the quantity of urban air temperature data intended for the analysis of their spatial distribution. A new measurement approach using local transport buses as "riding thermometers" is presented. By this means, temperature data with a very high temporal and spatial resolution could be collected during scheduled bus rides. The data obtained provide the basis for the identification of thermally affected areas and for the investigation of factors in urban structure which influence the thermal conditions. Initial results from the ongoing study, which show the temperature distribution along different traverses through the city of Aachen, are presented.

  14. Emissions of an AVCO Lycoming 0-320-DIAD air cooled light aircraft engine as a function of fuel-air ratio, timing, and air temperature and humidity

    NASA Technical Reports Server (NTRS)

    Meng, P. R.; Skorobatckyi, M.; Cosgrove, D. V.; Kempke, E. E., Jr.

    1976-01-01

    A carbureted aircraft engine was operated over a range of test conditions to establish the exhaust levels over the EPA seven-mode emissions cycle. Baseline (full rich production limit) exhaust emissions at an induction air temperature of 59 F and near zero relative humidity were 90 percent of the EPA standard for HC, 35 percent for NOx, and 161 percent for CO. Changes in ignition timing around the standard 25 deg BTDC from 30 deg BTDC to 20 deg BTDC had little effect on the exhaust emissions. Retarding the timing to 15 deg BTDC increased both the HC and CO emissions and decreased NOx emissions. HC and CO emissions decreased as the carburetor was leaned out, while NOx emissions increased. The EPA emission standards were marginally achieved at two leanout conditions. Variations in the quantity of cooling air flow over the engine had no effect on exhaust emissions. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased.

  15. Cool Roofs in Guangzhou, China: Outdoor Air Temperature Reductions during Heat Waves and Typical Summer Conditions.

    PubMed

    Cao, Meichun; Rosado, Pablo; Lin, Zhaohui; Levinson, Ronnen; Millstein, Dev

    2015-12-15

    In this paper, we simulate temperature reductions during heat-wave events and during typical summer conditions from the installation of highly reflective "cool" roofs in the Chinese megacity of Guangzhou. We simulate temperature reductions during six of the strongest historical heat-wave events over the past decade, finding average urban midday temperature reductions of 1.2 °C. In comparison, we simulate 25 typical summer weeks between 2004 and 2008, finding average urban midday temperature reductions of 0.8 °C, indicating that air temperature sensitivity to urban albedo in Guangzhou varies with meteorological conditions. We find that roughly three-fourths of the variance in air temperature reductions across all episodes can be accounted for by a linear regression, including only three basic properties related to the meteorological conditions: mean daytime temperature, humidity, and ventilation to the greater Guangzhou urban area. While these results highlight the potential for cool roofs to mitigate peak temperatures during heat waves, the temperature reductions reported here are based on the upper bound case, which increases albedos of all roofs (but does not modify road albedo or wall albedo).

  16. Equatorial range limits of an intertidal ectotherm are more linked to water than air temperature.

    PubMed

    Seabra, Rui; Wethey, David S; Santos, António M; Gomes, Filipa; Lima, Fernando P

    2016-10-01

    As climate change is expected to impose increasing thermal stress on intertidal organisms, understanding the mechanisms by which body temperatures translate into major biogeographic patterns is of paramount importance. We exposed individuals of the limpet Patella vulgata Linnaeus, 1758, to realistic experimental treatments aimed at disentangling the contribution of water and air temperature for the buildup of thermal stress. Treatments were designed based on temperature data collected at the microhabitat level, from 15 shores along the Atlantic European coast spanning nearly 20° of latitude. Cardiac activity data indicated that thermal stress levels in P. vulgata are directly linked to elevated water temperature, while high air temperature is only stressful if water temperature is also high. In addition, the analysis of the link between population densities and thermal regimes at the studied locations suggests that the occurrence of elevated water temperature may represent a threshold P. vulgata is unable to tolerate. By combining projected temperatures with the temperature threshold identified, we show that climate change will likely result in the westward expansion of the historical distribution gap in the Bay of Biscay (southwest France), and northward contraction of the southern range limit in south Portugal. These findings suggest that even a minor relaxing of the upwelling off northwest Iberia could lead to a dramatic increase in thermal stress, with major consequences for the structure and functioning of the intertidal communities along Iberian rocky shores.

  17. 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

    2017-01-01

    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.

  18. [Effects of sudden air temperature and pressure changes on mortality in the Czech Republic].

    PubMed

    Plavcová, E; Kyselý, J

    2009-04-01

    We have developed an algorithm for identifying sudden changes in air pressure and temperature over the Czech Republic. Such events were retrieved from the data covering in 1986-2005 and were matched with the daily numbers of all-cause deaths and deaths due to cardiovascular diseases from the national database, separately for the whole population and that aged 70 years and over. Excess daily mortality was determined by calculating deviations of the observed number of deaths from the expected number of deaths for each day in the respective groups. The relative deviation of the mortality the mean was calculated as the ratio of the excess mortality to the expected number of deaths. We used 3-hour air pressure data from 10 meteorological stations and hourly air temperature data from 9 stations representative of the Czech Republic. Pressure changes were evaluated on time scales of 3, 6 and 12 hours, separately for summer and winter time. Temperature changes were evaluated on a 24-hour time scale, separately for summer and winter season. Events characterized by pressure or temperature changes above the critical threshold and recorded within 24 hours at more than 50% of meteorological stations were retrieved. The critical thresholds were defined separately for each station using quantiles of distributions of air pressure and temperature changes. Relative mortality deviations for days D-2 (2 days before the change) to D+7 (7 days after the change) were averaged over the retrieved events. Statistical significance of the mean relative deviation was tested using the Monte Carlo method. Increased mortality followed large temperature increases and large pressure drops both in summer and winter months. Decreased mortality was observed after large pressure increases and large temperature drops in summer. Mortality variations are usually more pronounced in the population aged 70 years and over, and cardiovascular diseases account for most deaths after sudden temperature changes.

  19. GSOD Based Daily Global Mean Surface Temperature and Mean Sea Level Air Pressure (1982-2011)

    SciTech Connect

    Xuan Shi, Dali Wang

    2014-05-05

    This data product contains all the gridded data set at 1/4 degree resolution in ASCII format. Both mean temperature and mean sea level air pressure data are available. It also contains the GSOD data (1982-2011) from NOAA site, contains station number, location, temperature and pressures (sea level and station level). The data package also contains information related to the data processing methods

  20. Effects of light intensity light quality and air velocity on temperature in plant reproductive organs

    NASA Astrophysics Data System (ADS)

    Kitaya, Y.; Hirai, H.

    Excess temperature increase in plant reproductive organs such as anthers and stigmata could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions in closed plant growth facilities There is a possibility that the aberration was caused by an excess increase in temperatures of reproductive organs in Bioregenerative Life Support Systems under microgravity conditions in space The fundamental study was conducted to know the thermal situation of the plant reproductive organs as affected by light intensity light quality and air velocity on the earth and to estimate the excess temperature increase in the reproductive organs in closed plant growth facilities in space Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at an air temperature of 10 r C The temperatures in flowers at 300 mu mol m -2 s -1 PPFD under the lights from red LEDs white LEDs blue LEDs fluorescent lamps and incandescent lamps increased by 1 4 1 7 1 9 6 0 and 25 3 r C respectively for rice and by 2 8 3 4 4 1 7 8 and 43 4 r C respectively for strawberry The flower temperatures increased with increasing PPFD levels The temperatures in petals anthers and stigmas of strawberry at 300 mu mol m -2 s -1 PPFD under incandescent lamps increased by 32 7 29 0 and 26 6 r C respectively at 0 1 m s -1 air velocity and by 20 6 18 5 and 15 9 r C respectively at 0 8 m s -1 air velocity The temperatures of reproductive organs decreased with increasing

  1. Heat Exchange with Air and Temperature Profile of a Moving Oversize Tire

    NASA Astrophysics Data System (ADS)

    Grinchuk, P. S.; Fisenko, S. P.

    2016-11-01

    A one-dimensional mathematical model of heat transfer in a tire with account for the deformation energy dissipation and heat exchange of a moving tire with air has been developed. The mean temperature profiles are calculated and transition to a stationary thermal regime is considered. The influence of the rate of energy dissipation and of effective thermal conductivity of rubber on the temperature field is investigated quantitatively.

  2. Elevation of nasal mucosal temperature increases the ability of the nose to warm and humidify air.

    PubMed

    Abbott, D J; Baroody, F M; Naureckas, E; Naclerio, R M

    2001-01-01

    The nose functions to warm and humidify inspired air. The factors that influence these functions have been studied to a limited degree. We have developed a method for measuring the temperature and relative humidity of the air before and after nasal conditioning to study nasal function. In this experiment we studied the effects of raising the mucosal surface temperature by immersion of the feet in warm water. Six subjects (avg. age = 27.0 years) were randomized to immersion of the feet in 30 degrees C and 40 degrees C water. The nasal mucosal temperature increased significantly from the 32.2+/-1.3 degrees C during immersion in the 30 degrees C water to the 33.1+/-1.2 degrees C during immersion in 40 degrees water (p < 0.05). No significant difference in nasal volume was noted between the 30 degrees (17.8+/-4.5 cc) and the 40 degrees (17.7+/-5.3 cc) immersions. There was a significant increase in the conditioning capacity of the nose (as measured by total water content of inspired air) in response to cold-air challenge during the 40 degrees immersion (1669+/-312 mg water) when compared to the 30 degrees immersion (1324+/-152 mg water). From these data we deduce that warming of the nasal mucosa improves the ability of the nose to condition inspired air without a significant change in the volume of the nasal cavity.

  3. Regional change in snow water equivalent-surface air temperature relationship over Eurasia during boreal spring

    NASA Astrophysics Data System (ADS)

    Wu, Renguang; Chen, Shangfeng

    2016-10-01

    Present study investigates local relationship between surface air temperature and snow water equivalent (SWE) change over mid- and high-latitudes of Eurasia during boreal spring. Positive correlation is generally observed around the periphery of snow covered region, indicative of an effect of snow on surface temperature change. In contrast, negative correlation is usually found over large snow amount area, implying a response of snow change to wind-induced surface temperature anomalies. With the seasonal retreat of snow covered region, region of positive correlation between SWE and surface air temperature shifts northeastward from March to May. A diagnosis of surface heat flux anomalies in April suggests that the snow impact on surface air temperature is dominant in east Europe and west Siberia through modulating surface shortwave radiation. In contrast, atmospheric effect on SWE is important in Siberia and Russia Far East through wind-induced surface sensible heat flux change. Further analysis reveals that atmospheric circulation anomalies in association with snowmelt over east Siberia may be partly attributed to sea surface temperature anomalies in the North Atlantic and the atmospheric circulation anomaly pattern associated with snowmelt over Russia Far East has a close association with the Arctic Oscillation.

  4. Computational Fluid Dynamics Analysis on Radiation Error of Surface Air Temperature Measurement

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Liu, Qing-Quan; Ding, Ren-Hui

    2017-01-01

    Due to solar radiation effect, current air temperature sensors inside a naturally ventilated radiation shield may produce a measurement error that is 0.8 K or higher. To improve air temperature observation accuracy and correct historical temperature of weather stations, a radiation error correction method is proposed. The correction method is based on a computational fluid dynamics (CFD) method and a genetic algorithm (GA) method. The CFD method is implemented to obtain the radiation error of the naturally ventilated radiation shield under various environmental conditions. Then, a radiation error correction equation is obtained by fitting the CFD results using the GA method. To verify the performance of the correction equation, the naturally ventilated radiation shield and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated temperature measurement platform serves as an air temperature reference. The mean radiation error given by the intercomparison experiments is 0.23 K, and the mean radiation error given by the correction equation is 0.2 K. This radiation error correction method allows the radiation error to be reduced by approximately 87 %. The mean absolute error and the root mean square error between the radiation errors given by the correction equation and the radiation errors given by the experiments are 0.036 K and 0.045 K, respectively.

  5. Meristem temperature substantially deviates from air temperature even in moderate environments: is the magnitude of this deviation species-specific?

    PubMed

    Savvides, Andreas; van Ieperen, Wim; Dieleman, Janneke A; Marcelis, Leo F M

    2013-11-01

    Meristem temperature (Tmeristem ) drives plant development but is hardly ever quantified. Instead, air temperature (Tair ) is usually used as its approximation. Meristems are enclosed within apical buds. Bud structure and function may differ across species. Therefore, Tmeristem may deviate from Tair in a species-specific way. Environmental variables (air temperature, vapour pressure deficit, radiation, and wind speed) were systematically varied to quantify the response of Tmeristem . This response was related to observations of bud structure and transpiration. Tomato and cucumber plants were used as model plants as they are morphologically distinct and usually growing in similar environments. Tmeristem substantially deviated from Tair in a species-specific manner under moderate environments. This deviation ranged between -2.6 and 3.8 °C in tomato and between -4.1 and 3.0 °C in cucumber. The lower Tmeristem observed in cucumber was linked with the higher transpiration of the bud foliage sheltering the meristem when compared with tomato plants. We here indicate that for properly linking growth and development of plants to temperature in future applications, for instance in climate change scenarios studies, Tmeristem should be used instead of Tair , as a species-specific trait highly reliant on various environmental factors.

  6. Application of 3-D Urbanization Index to Assess Impact of Urbanization on Air Temperature

    PubMed Central

    Wu, Chih-Da; Lung, Shih-Chun Candice

    2016-01-01

    The lack of appropriate methodologies and indicators to quantify three-dimensional (3-D) building constructions poses challenges to authorities and urban planners when formulating polices to reduce health risks due to heat stress. This study evaluated the applicability of an innovative three-dimensional Urbanization Index (3DUI), based on remote sensing database, with a 5 m spatial resolution of 3-D man-made constructions to representing intra-urban variability of air temperature by assessing correlation of 3DUI with air temperature from a 3-D perspective. The results showed robust high correlation coefficients, ranging from 0.83 to 0.85, obtained within the 1,000 m circular buffer around weather stations regardless of season, year, or spatial location. Our findings demonstrated not only the strength of 3DUI in representing intra-urban air-temperature variability, but also its great potential for heat stress assessment within cities. In view of the maximum correlation between building volumes within the 1,000 m circular buffer and ambient air temperature, urban planning should consider setting ceilings for man-made construction volume in each 2 × 2 km2 residential community for thermal environment regulation, especially in Asian metropolis with high population density in city centers. PMID:27079537

  7. Application of 3-D Urbanization Index to Assess Impact of Urbanization on Air Temperature

    NASA Astrophysics Data System (ADS)

    Wu, Chih-Da; Lung, Shih-Chun Candice

    2016-04-01

    The lack of appropriate methodologies and indicators to quantify three-dimensional (3-D) building constructions poses challenges to authorities and urban planners when formulating polices to reduce health risks due to heat stress. This study evaluated the applicability of an innovative three-dimensional Urbanization Index (3DUI), based on remote sensing database, with a 5 m spatial resolution of 3-D man-made constructions to representing intra-urban variability of air temperature by assessing correlation of 3DUI with air temperature from a 3-D perspective. The results showed robust high correlation coefficients, ranging from 0.83 to 0.85, obtained within the 1,000 m circular buffer around weather stations regardless of season, year, or spatial location. Our findings demonstrated not only the strength of 3DUI in representing intra-urban air-temperature variability, but also its great potential for heat stress assessment within cities. In view of the maximum correlation between building volumes within the 1,000 m circular buffer and ambient air temperature, urban planning should consider setting ceilings for man-made construction volume in each 2 × 2 km2 residential community for thermal environment regulation, especially in Asian metropolis with high population density in city centers.

  8. Response of sugarcane to carbon dioxide enrichment and elevated air temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four sugarcane cultivars (CP 72-2086, CP 73-1547, CP 88-1508, and CP 80-1827) were grown in elongated temperature-gradient greenhouses (TGG) at ambient or elevated carbon dioxide (CO2) of 360 or 720 µmol CO2 mol-1 air (ppm, mole fraction basis), respectively. Elevated CO2 was maintained by injection...

  9. Room temperature, air crystallized perovskite film for high performance solar cells

    SciTech Connect

    Dubey, Ashish; Kantack, Nicholas; Adhikari, Nirmal; Reza, Khan Mamun; Venkatesan, Swaminathan; Kumar, Mukesh; Khatiwada, Devendra; Darling, Seth; Qiao, Qiquan

    2016-05-31

    For the first time, room temperature heating free growth and crystallization of perovskite films in ambient air without the use of thermal annealing is reported. Highly efficient perovskite nanorod-based solar cells were made using ITO/PEDOT:PSS/CH3NH3PbI3 nanorods/PC60BM/rhodamine/Ag. All the layers except PEDOT:PSS were processed at room temperature thereby eliminating the need for thermal treatment. Perovskite films were spin coated inside a N-2 filled glovebox and immediately were taken outside in air having 40% relative humidity (RH). Exposure to humid air was observed to promote the crystallization process in perovskite films even at room temperature. Perovskite films kept for 5 hours in ambient air showed nanorod-like morphology having high crystallinity, with devices exhibiting the highest PCE of 16.83%, which is much higher than the PCE of 11.94% for traditional thermally annealed perovskite film based devices. Finally, it was concluded that moisture plays an important role in room temperature crystallization of pure perovskite nanorods, showing improved optical and charge transport properties, which resulted in high performance solar cells.

  10. Room temperature, air crystallized perovskite film for high performance solar cells

    DOE PAGES

    Dubey, Ashish; Kantack, Nicholas; Adhikari, Nirmal; ...

    2016-05-31

    For the first time, room temperature heating free growth and crystallization of perovskite films in ambient air without the use of thermal annealing is reported. Highly efficient perovskite nanorod-based solar cells were made using ITO/PEDOT:PSS/CH3NH3PbI3 nanorods/PC60BM/rhodamine/Ag. All the layers except PEDOT:PSS were processed at room temperature thereby eliminating the need for thermal treatment. Perovskite films were spin coated inside a N-2 filled glovebox and immediately were taken outside in air having 40% relative humidity (RH). Exposure to humid air was observed to promote the crystallization process in perovskite films even at room temperature. Perovskite films kept for 5 hours inmore » ambient air showed nanorod-like morphology having high crystallinity, with devices exhibiting the highest PCE of 16.83%, which is much higher than the PCE of 11.94% for traditional thermally annealed perovskite film based devices. Finally, it was concluded that moisture plays an important role in room temperature crystallization of pure perovskite nanorods, showing improved optical and charge transport properties, which resulted in high performance solar cells.« less

  11. Cloud-induced uncertainties in AIRS and ECMWF temperature and specific humidity

    NASA Astrophysics Data System (ADS)

    Wong, Sun; Fetzer, Eric J.; Schreier, Mathias; Manipon, Gerald; Fishbein, Evan F.; Kahn, Brian H.; Yue, Qing; Irion, Fredrick W.

    2015-03-01

    The uncertainties of the Atmospheric Infrared Sounder (AIRS) Level 2 version 6 specific humidity (q) and temperature (T) retrievals are quantified as functions of cloud types by comparison against Integrated Global Radiosonde Archive radiosonde measurements. The cloud types contained in an AIRS/Advanced Microwave Sounding Unit footprint are identified by collocated Moderate Resolution Imaging Spectroradiometer retrieved cloud optical depth (COD) and cloud top pressure. We also report results of similar validation of q and T from European Centre for Medium-Range Weather Forecasts (ECMWF) forecasts (EC) and retrievals from the AIRS Neural Network (NNW), which are used as the initial state for AIRS V6 physical retrievals. Differences caused by the variation in the measurement locations and times are estimated using EC, and all the comparisons of data sets against radiosonde measurements are corrected by these estimated differences. We report in detail the validation results for AIRS GOOD quality control, which is used for the AIRS Level 3 climate products. AIRS GOOD quality q reduces the dry biases inherited from the NNW in the middle troposphere under thin clouds but enhances dry biases in thick clouds throughout the troposphere (reaching -30% at 850 hPa near deep convective clouds), likely because the information contained in AIRS retrievals is obtained in cloud-cleared areas or above clouds within the field of regard. EC has small moist biases (~5-10%), which are within the uncertainty of radiosonde measurements, in thin and high clouds. Temperature biases of all data are within ±1 K at altitudes above the 700 hPa level but increase with decreasing altitude. Cloud-cleared retrievals lead to large AIRS cold biases (reaching about -2 K) in the lower troposphere for large COD, enhancing the cold biases inherited from the NNW. Consequently, AIRS GOOD quality T root-mean-squared errors (RMSEs) are slightly smaller than the NNW errors in thin clouds (1.5-2.5 K) but

  12. Using Satellite-Based Spatiotemporal Resolved Air Temperature Exposure to Study the Association between Ambient Air Temperature and Birth Outcomes in Massachusetts

    PubMed Central

    Melly, Steven J.; Coull, Brent A.; Nordio, Francesco; Schwartz, Joel D.

    2015-01-01

    Background Studies looking at air temperature (Ta) and birth outcomes are rare. Objectives We investigated the association between birth outcomes and daily Ta during various prenatal exposure periods in Massachusetts (USA) using both traditional Ta stations and modeled addresses. Methods We evaluated birth outcomes and average daily Ta during various prenatal exposure periods in Massachusetts (USA) using both traditional Ta stations and modeled address Ta. We used linear and logistic mixed models and accelerated failure time models to estimate associations between Ta and the following outcomes among live births > 22 weeks: term birth weight (≥ 37 weeks), low birth weight (LBW; < 2,500 g at term), gestational age, and preterm delivery (PT; < 37 weeks). Models were adjusted for individual-level socioeconomic status, traffic density, particulate matter ≤ 2.5 μm (PM2.5), random intercept for census tract, and mother’s health. Results Predicted Ta during multiple time windows before birth was negatively associated with birth weight: Average birth weight was 16.7 g lower (95% CI: –29.7, –3.7) in association with an interquartile range increase (8.4°C) in Ta during the last trimester. Ta over the entire pregnancy was positively associated with PT [odds ratio (OR) = 1.02; 95% CI: 1.00, 1.05] and LBW (OR = 1.04; 95% CI: 0.96, 1.13). Conclusions Ta during pregnancy was associated with lower birth weight and shorter gestational age in our study population. Citation Kloog I, Melly SJ, Coull BA, Nordio F, Schwartz JD. 2015. Using satellite-based spatiotemporal resolved air temperature exposure to study the association between ambient air temperature and birth outcomes in Massachusetts. Environ Health Perspect 123:1053–1058; http://dx.doi.org/10.1289/ehp.1308075 PMID:25850104

  13. Temperature differences in the air layer close to a road surface

    NASA Astrophysics Data System (ADS)

    Bogren, Jörgen; Gustavsson, Torbjörn; Karlsson, Maria

    2001-12-01

    In this study, profiles of temperature and humidity (<250 cm above the road and 5 m into the surroundings) have been used to examine the development of temperature differences in the air layer close to the road. Temperature, humidity and wind profiles were measured, together with net radiation and observations of road surface state, at a test site at Road 45, Surte, Sweden. Measured temperature differences were compared with present weather, preceding weather, surface status, wind direction and other parameters thought to be important for the development of temperature differences. The results showed that large temperature differences (1-3 °C between 250 cm and 10 cm above the road) occurred when there was a high risk of slipperiness caused by hoarfrost, snow or ice on the road. The temperature differences between different levels were associated with the exchange of humidity and temperature between the air layer and the road surface. The 10 cm level reflected the surface processes well. Higher levels were influenced by the surroundings because of turbulence and advection. This study emphasises the need for measurements to be taken at a height and place that reflects the processes at the road surface.

  14. Laminar Flame Velocity and Temperature Exponent of Diluted DME-Air Mixture

    NASA Astrophysics Data System (ADS)

    Naseer Mohammed, Abdul; Anwar, Muzammil; Juhany, Khalid A.; Mohammad, Akram

    2017-03-01

    In this paper, the laminar flame velocity and temperature exponent diluted dimethyl ether (DME) air mixtures are reported. Laminar premixed mixture of DME-air with volumetric dilutions of carbon dioxides (CO2) and nitrogen (N2) are considered. Experiments were conducted using a preheated mesoscale high aspect-ratio diverging channel with inlet dimensions of 25 mm × 2 mm. In this method, flame velocities are extracted from planar flames that were stabilized near adiabatic conditions inside the channel. The flame velocities are then plotted against the ratio of mixture temperature and the initial reference temperature. A non-linear power law regression is observed suitable. This regression analysis gives the laminar flame velocity at the initial reference temperature and temperature exponent. Decrease in the laminar flame velocity and increase in temperature exponent is observed for CO2 and N2 diluted mixtures. The addition of CO2 has profound influence when compared to N2 addition on both flame velocity and temperature exponent. Numerical prediction of the similar mixture using a detailed reaction mechanism is obtained. The computational mechanism predicts higher magnitudes for laminar flame velocity and smaller magnitudes of temperature exponent compared to experimental data.

  15. Advances in Fast-response Acoustically Derived Air-temperature Measurements

    NASA Astrophysics Data System (ADS)

    Bogoev, I.; Jacobsen, L.; Horst, T. W.; Conrad, B.

    2015-12-01

    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.

  16. Effects of different dentin thicknesses and air cooling on pulpal temperature rise during laser welding.

    PubMed

    Secilmis, Asli; Bulbul, Mehmet; Sari, Tugrul; Usumez, Aslihan

    2013-01-01

    The neodymium/yttrium-aluminum-garnet (Nd/YAG) laser has been suggested to repair broken prostheses in the mouth. This study investigated the effects of different dentin thicknesses and air cooling on pulpal temperature rise during laser welding. Three intact human maxillary molars were prepared for full-veneer crown. For each tooth, dentin thicknesses in mesiobuccal cusp was 2, 3, or 4 mm. Twenty dies were duplicated from each of the prepared teeth. For metal copings with 0.5-mm thickness, wax patterns were prepared with dip wax technique directly onto each of dies. All patterns were sprued and invested. The castings were made using a nickel-chromium alloy (Nicromed Premium, Neodontics). A hole with 0.5-mm diameter was prepared on the mesiobuccal cusp of each crown. The Nd/YAG laser (9.85 W; 1 Hz repetition rate; fluence, 1.230 J/cm(2); Fidelis Plus 3, Fotona) was used for welding with or without air cooling (n = 10). The temperature rise was measured in pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Differences between start and highest temperature reading were taken, and temperature rise values were compared using two-way analysis of variance and Tukey's honestly significant difference tests (α = .05). Pulpal temperature rise varied significantly depending on the dentin thickness and air cooling (p < 0.05). The non-air cooling group induced significantly the highest temperature increases. There were no significant differences between 2- and 3-mm dentin thicknesses groups (p > 0.05); however, pulpal temperature rise was the lowest for 4-mm dentin thickness group (p < 0.05). The highest values of thermal increase were found in the pulp chamber (6.8°C) when no air cooling was used in 2-mm dentin thickness group. Laser welding on base metal castings with Nd/YAG laser can be applied with air cooling to avoid temperature rises known to adversely affect pulpal health when dentin thickness is 2 or 3 mm.

  17. Impacts of drought on leaf respiration in darkness and light in Eucalyptus saligna exposed to industrial-age atmospheric CO₂ and growth temperature.

    PubMed

    Ayub, Gohar; Smith, Renee A; Tissue, David T; Atkin, Owen K

    2011-06-01

    Our study assessed the impact of a wide range of industrial-age climate scenarios on leaf respiration (R) in Eucalyptus saligna. Well-watered or sustained drought-treated plants were grown in glasshouses differing in atmospheric CO₂ concentration ([CO₂]) (280, 400 and 640 μl l⁻¹) and temperature (26 and 30°C). Rates of R in darkness (R(dark) ) and light (R(light) ), photosynthesis (A) and related leaf traits (mass : area relationships, and nitrogen, phosphorus, starch and sugar concentrations) were measured. Light inhibited R in all cases (R(light) < R(dark) ) (well-watered: 40%; drought-treated: 73%). Growth [CO₂] and temperature had little impact on area-based rates of R(dark) or R(light) , with R(light) exhibiting minimal thermal acclimation. By contrast, sustained drought resulted in reduced R(dark), R(light) and A, with the inhibitory effect of drought on A and R(light) (c. 50-70%) greater than that on R(dark) (c. 15%). Drought effects were fully reversible after watering. Variability in R(light) appeared to be dependent on the underlying rate of R(dark) and associated Rubisco activity. Collectively, our data suggest that there is an asynchronous response of leaf carbon metabolism to drought, and a tighter coupling between R(light) and A than between R(dark) and A, under both past and future climate scenarios. These findings have important implications for ecosystem/global models seeking to predict carbon cycling.

  18. STUDY ON AIR INGRESS MITIGATION METHODS IN THE VERY HIGH TEMPERATURE GAS COOLED REACTOR (VHTR)

    SciTech Connect

    Chang H. Oh

    2011-03-01

    An air-ingress accident followed by a pipe break is considered as a critical event for a very high temperature gas-cooled reactor (VHTR). Following helium depressurization, it is anticipated that unless countermeasures are taken, air will enter the core through the break leading to oxidation of the in-core graphite structure. Thus, without mitigation features, this accident might lead to severe exothermic chemical reactions of graphite and oxygen. Under extreme circumstances, a loss of core structural integrity may occur along with excessive release of radiological inventory. Idaho National Laboratory under the auspices of the U.S. Department of Energy is performing research and development (R&D) that focuses on key phenomena important during challenging scenarios that may occur in the VHTR. Phenomena Identification and Ranking Table (PIRT) studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important (Oh et al. 2006, Schultz et al. 2006). Consequently, the development of advanced air ingress-related models and verification and validation (V&V) requirements are part of the experimental validation plan. This paper discusses about various air-ingress mitigation concepts applicable for the VHTRs. The study begins with identifying important factors (or phenomena) associated with the air-ingress accident by using a root-cause analysis. By preventing main causes of the important events identified in the root-cause diagram, the basic air-ingress mitigation ideas can be conceptually derived. The main concepts include (1) preventing structural degradation of graphite supporters; (2) preventing local stress concentration in the supporter; (3) preventing graphite oxidation; (4) preventing air ingress; (5) preventing density gradient driven flow; (4) preventing fluid density gradient; (5) preventing fluid temperature gradient; (6) preventing high temperature. Based on the basic concepts listed above, various air

  19. Temperature measurements in hypersonic air flows using laser-induced O2 fluorescence

    NASA Technical Reports Server (NTRS)

    Laufer, Gabriel; Mckenzie, Robert L.

    1988-01-01

    An investigation is reported of the use of laser-induced fluorescence on oxygen for the measurement of air temperature and its fluctuations owing to turbulence in hypersonic wind tunnel flows. The results show that for temperatures higher than 60 K and densities higher than 0.01 amagat, the uncertainty in the temperature measurement can be less than 2 percent if it is limited by photon-statistical noise. The measurement is unaffected by collisional quenching and, if the laser fluence is kept below 1.5 J/sq cm, it is also unaffected by nonlinear effects which are associated with depletion of the absorbing states.

  20. Neutral air density and temperature measurements by the TOTAL instrument aboard the ROSE payloads

    NASA Astrophysics Data System (ADS)

    Friker, A.; Luebken, F.-J.

    1992-06-01

    Four ROSE payloads, launched from November 1988 to February 1989 from northern Scandinavia, carried ionization gauges ('TOTAL' instruments) for neutral air density measurements in the altitude range 90-105 km. Temperature profiles are derived by integrating the number density profiles. Density and temperature data are presented. The limitations of the measurement technique as well as instrumental errors are discussed. In one of the flights (F1) a significant temperature enhancement was observed at an altitude where plasma instabilities were detected by independent measurements.

  1. Measurement of temperature and velocity fields in a convective fluid flow in air using schlieren images.

    PubMed

    Martínez-González, A; Moreno-Hernández, D; Guerrero-Viramontes, J A

    2013-08-01

    A convective fluid flow in air could be regulated if the physical process were better understood. Temperature and velocity measurements are required in order to obtain a proper characterization of a convective fluid flow. In this study, we show that a classical schlieren system can be used for simultaneous measurements of temperature and velocity in a convective fluid flow in air. The schlieren technique allows measurement of the average fluid temperature and velocity integrated in the direction of the test beam. Therefore, in our experiments we considered surfaces with isothermal conditions. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow by using optical flow techniques. The algorithm implemented analyzes motion between consecutive schlieren frames to obtain a tracked sequence and finally velocity fields. The proposed technique was applied to measure the temperature and velocity fields in natural convection of air due to unconfined and confined heated rectangular plates.

  2. Air - water temperature relationships in the trout streams of southeastern Minnesota’s carbonate - sandstone landscape

    USGS Publications Warehouse

    Krider, Lori A.; Magner, Joseph A.; Perry, Jim; Vondracek, Bruce C.; Ferrington, Leonard C.

    2013-01-01

    Carbonate-sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface-water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater-fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air-water temperature relationships for 40 GWFS in southeastern Minnesota. A 40-stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R2 of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface-water dominated streams. Regression models for streams with high R2 values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater-fed systems, but will do so at a slower rate than surface-water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.

  3. Effects of light intensity and air velocity on air temperature, water vapor pressure, and CO2 concentration inside a plant canopy under an artificial lighting condition.

    PubMed

    Kitaya, Y; Shibuya, T; Kozai, T; Kubota, C

    1998-01-01

    In order to characterize environmental variables inside a plant canopy under artificial lighting in the CELSS, we investigated the effects of light intensity and air velocity on air temperature, water vapor pressure, and CO2 concentration inside a plant canopy. Under a PPF of 500 micromoles m-2 s-1, air temperature was 2-3 degrees C higher, water vapor pressure was 0.6 kPa higher, and CO2 concentration was 25-35 micromoles mol-1 lower at heights ranging from 0 to 30 mm below the canopy than at a height 60 mm above the canopy. Increasing the PPF increased air temperature and water vapor pressure and decreased CO2 concentration inside the canopy. The air temperature was lower and the CO2 concentration was higher inside the canopy at an air velocity of 0.3 m s-1 than at an air velocity of 0.1 m s-1. The environmental variables inside the canopy under a high light intensity were characterized by higher air temperature, higher vapor pressure, and lower CO2 concentration than those outside the canopy.

  4. Effects of elevated CO₂ and temperature on photosynthesis and leaf traits of an understory dwarf bamboo in subalpine forest zone, China.

    PubMed

    Li, Yongping; Zhang, Yuanbin; Zhang, Xiaolu; Korpelainen, Helena; Berninger, Frank; Li, Chunyang

    2013-06-01

    The dwarf bamboo (Fargesia rufa Yi), growing understory in subalpine dark coniferous forest, is one of the main foods for giant panda, and it influences the regeneration of subalpine coniferous forests in southwestern China. To investigate the effects of elevated CO₂, temperature and their combination, the dwarf bamboo plantlets were exposed to two CO₂ regimes (ambient and double ambient CO₂ concentration) and two temperatures (ambient and +2.2°C) in growth chambers. Gas exchange, leaf traits and carbohydrates concentration were measured after the 150-day experiment. Elevated CO₂ significantly increased the net photosynthetic rate (Anet ), intrinsic water-use efficiency (WUEi ) and carbon isotope composition (δ¹³C) and decreased stomatal conductance (g(s)) and total chlorophyll concentration based on mass (Chl(m)) and area (Chl(a)). On the other hand, elevated CO₂ decreased specific leaf area (SLA), which was increased by elevated temperature. Elevated CO₂ also increased foliar carbon concentration based on mass (C(m)) and area (C(a)), nitrogen concentration based on area (N(a)), carbohydrates concentration (i.e. sucrose, sugar, starch and non-structural carbohydrates) and the slope of the A(net)-N(a) relationship. However, elevated temperature decreased C(m), C(a) and N(a). The combination of elevated CO₂ and temperature hardly affected SLA, C(m), C(a), N(m), N(a), Chl(m) and Chl(a). Variables Anet and Na had positive linear relationships in all treatments. Our results showed that photosynthetic acclimation did not occur in dwarf bamboo at elevated CO₂ and it could adjust physiology and morphology to enable the capture of more light, to increase WUE and improve nutritional conditions.

  5. INVESTIGATION OF A NOVEL AIR BRAZING COMPOSITION FOR HIGH-TEMPERATURE, OXIDATION-RESISTANT CERAMIC JOINING

    SciTech Connect

    Weil, K. Scott; Hardy, John S.; Darsell, Jens T.

    2004-01-30

    One of the challenges in developing a useful ceramic joining technique is in producing a joint that offers good strength under high temperature and highly oxidizing operating conditions. Unfortunately many of the commercially available active metal ceramic brazing alloys exhibit oxidation behaviors which are unacceptable for use in a high temperature application. We have developed a new approach to ceramic brazing, referred to as air brazing, that employs an oxide wetting agent dissolved in a molten noble metal solvent, in this case CuO in Ag, such that acceptable wetting behavior occurs on a number of ceramic substrates. In an effort to explore how to increase the operating temperature of this type of braze, we have investigated the effect of ternary palladium additions on the wetting characteristics of our standard Ag-CuO air braze composition

  6. Improving 7-Day Forecast Skill by Assimilation of Retrieved AIRS Temperature Profiles

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Rosenberg, Bob

    2016-01-01

    We conducted a new set of Data Assimilation Experiments covering the period January 1 to February 29, 2016 using the GEOS-5 DAS. Our experiments assimilate all data used operationally by GMAO (Control) with some modifications. Significant improvement in Global and Southern Hemisphere Extra-tropical 7-day forecast skill was obtained when: We assimilated AIRS Quality Controlled temperature profiles in place of observed AIRS radiances, and also did not assimilate CrISATMS radiances, nor did we assimilate radiosonde temperature profiles or aircraft temperatures. This new methodology did not improve or degrade 7-day Northern Hemispheric Extra-tropical forecast skill. We are conducting experiments aimed at further improving of Northern Hemisphere Extra-tropical forecast skill.

  7. Precipitation and Air Temperature Impact on Seasonal Variations of Groundwater Levels

    NASA Astrophysics Data System (ADS)

    Vitola, Ilva; Vircavs, Valdis; Abramenko, Kaspars; Lauva, Didzis; Veinbergs, Arturs

    2012-12-01

    The aim of this study is to clarify seasonal effects of precipitation and temperature on groundwater level changes in monitoring stations of the Latvia University of Agriculture - Mellupīte, Bērze and Auce. Groundwater regime and level fluctuations depend on climatic conditions such as precipitation intensity, evapotranspiration, surface runoff and drainage, as well as other hydrological factors. The relationship between precipitation, air temperature and groundwater level fluctuations could also lead and give different perspective of possible changes in groundwater quality. Using mathematical statistics and graphic-analytic methods it is concluded that autumn and winter precipitation has the dominant impact on groundwater level fluctuations, whereas spring and summer season fluctuations are more dependent on the air temperature.

  8. Impact of air velocity, temperature, humidity, and air on long-term voc emissions from building products

    NASA Astrophysics Data System (ADS)

    Wolkoff, Peder

    The emissions of two volatile organic compounds (VOCs) of concern from five building products (BPs) were measured in the field and laboratory emission cell (FLEC) up to 250 d. The BPs (VOCs selected on the basis of abundance and low human odor thresholds) were: nylon carpet with latex backing (2-ethylhexanol, 4-phenylcyclohexene), PVC flooring (2-ethylhexanol, phenol), floor varnish on pretreated beechwood parquet (butyl acetate, N-methylpyrrolidone), sealant (hexane, dimethyloctanols), and waterborne wall paint on gypsum board (1,2-propandiol, Texanol). Ten different climate conditions were tested: four different air velocities from ca. 1 cm s -1 to ca. 9 cm s -1, three different temperatures (23, 35, and 60°C), two different relative humidities (0% and 50% RH), and pure nitrogen instead of clean air supply. Additionally, two sample specimen and two different batches were compared for repeatability and homogeneity. The VOCs were sampled on Tenax TA and determined by thermal desorption and gas chromatography (FID). Quantification was carried out by individual calibration of each VOC of concern. Concentration/time profiles of the selected VOCs (i.e. their concentration decay curves over time) in a standard room were used for comparison. Primary source emissions were not affected by the air velocity after a few days to any great extent. Both the temperature and relative humidity affected the emission rates, but depended strongly on the type of BP and type of VOC. Secondary (oxidative) source emissions were only observed for the PVC and for dimethyloctanols from the sealant. The time to reach a given concentration (emission rate) appears to be a good approach for future interlaboratory comparisons of BP's VOC emissions.

  9. Influence of Air Temperature Difference on the Snow Melting Simulation of SWAT Model

    NASA Astrophysics Data System (ADS)

    YAN, Y.; Onishi, T.

    2013-12-01

    The temperature-index models are commonly used to simulate the snowmelt process in mountain areas because of its good performance, low data requirements, and computational simplicity. Widely used distributed hydrological model: Soil and Water Assessment Tool (SWAT) model is also using a temperature-index module. However, the lack of monitoring air temperature data still involves uncertainties and errors in its simulation performance especially in data sparse area. Thus, to evaluate the different air temperature data influence on the snow melt of the SWAT model, five different air temperature data are applied in two different Russia basins (Birobidjan basin and Malinovka basin). The data include the monitoring air temperature data (TM), NCEP reanalysis data (TNCEP), the dataset created by inverse distance weighted interpolation (IDW) method (TIDW), the dataset created by improved IDW method considering the elevation influence (TIDWEle), and the dataset created by using linear regression and MODIS Land Surface Temperature (LST) data (TLST). Among these data, the TLST , the TIDW and TIDWEle data have the higher spatial density, while the TNCEP and TM DATA have the most valid monitoring value for daily scale. The daily simulation results during the snow melting seasons (March, April and May) showed reasonable results in both test basins for all air temperature data. While R2 and NSE in Birobidjan basin are around 0.6, these values in Malinovka basin are over 0.75. Two methods: Generalized Likelihood Uncertainty Estimation (GLUE) and Sequential Uncertainty Fitting, version. 2 (SUFI-2) were used for model calibration and uncertainty analysis. The evolution index is p-factor which means the percentage of measured data bracketed by the 95% Prediction Uncertainty (95PPU). The TLST dataset always obtained the best results in both basins compared with other datasets. On the other hand, the two IDW based method get the worst results among all the scenarios. Totally, the

  10. Contributions of photosynthetic and non-photosynthetic cell types to leaf respiration in Vicia faba L. and their responses to growth temperature.

    PubMed

    Long, Benedict M; Bahar, Nur H A; Atkin, Owen K

    2015-11-01

    In intact leaves, mitochondrial populations are highly heterogeneous among contrasting cell types; how such contrasting populations respond to sustained changes in the environment remains, however, unclear. Here, we examined respiratory rates, mitochondrial protein composition and response to growth temperature in photosynthetic (mesophyll) and non-photosynthetic (epidermal) cells from fully expanded leaves of warm-developed (WD) and cold-developed (CD) broad bean (Vicia faba L.). Rates of respiration were significantly higher in mesophyll cell protoplasts (MCPs) than epidermal cell protoplasts (ECPs), with both protoplast types exhibiting capacity for cytochrome and alternative oxidase activity. Compared with ECPs, MCPs contained greater relative quantities of porin, suggesting higher mitochondrial surface area in mesophyll cells. Nevertheless, the relative quantities of respiratory proteins (normalized to porin) were similar in MCPs and ECPs, suggesting that ECPs have lower numbers of mitochondria yet similar protein complement to MCP mitochondria (albeit with lower abundance serine hydroxymethyltransferase). Several mitochondrial proteins (both non-photorespiratory and photorespiratory) exhibited an increased abundance in response to cold in both protoplast types. Based on estimates of individual protoplast respiration rates, combined with leaf cell abundance data, epidermal cells make a small but significant (2%) contribution to overall leaf respiration which increases twofold in the cold. Taken together, our data highlight the heterogeneous nature of mitochondrial populations in leaves, both among contrasting cell types and in how those populations respond to growth temperature.

  11. Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2008-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AlRS data. Version 5 contains accurate case-by-case error estimates for most derived products, which are also used for quality control. We have conducted forecast impact experiments assimilating AlRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the NASA FVGCM. Assimilation of quality controlled temperature profiles resulted in significantly improved forecast skill in both the Northern Hemisphere and Southern Hemisphere Extra-Tropics, compared to that obtained from analyses obtained when all data used operationally by NCEP except for AlRS data is assimilated. Experiments using different Quality Control thresholds for assimilation of AlRS temperature retrievals showed that a medium quality control threshold performed better than a tighter threshold, which provided better overall sounding accuracy; or a looser threshold, which provided better spatial coverage of accepted soundings. We are conducting more experiments to further optimize this balance of spatial coverage and sounding accuracy from the data assimilation perspective. In all cases, temperature soundings were assimilated well below cloud level in partially cloudy cases. The positive impact of assimilating AlRS derived atmospheric temperatures all but vanished when only AIRS stratospheric temperatures were assimilated. Forecast skill resulting from assimilation of AlRS radiances uncontaminated by clouds, instead of AlRS temperature soundings, was only slightly better than that resulting from assimilation of only stratospheric AlRS temperatures. This reduction in forecast skill is most likely the result of significant loss of tropospheric information when only AIRS radiances unaffected by clouds are used in the data assimilation process.

  12. Air temperature evolution during dry spells and its relation to prevailing soil moisture regimes

    NASA Astrophysics Data System (ADS)

    Schwingshackl, Clemens; Hirschi, Martin; Seneviratne, Sonia I.

    2015-04-01

    The complex interplay between land and atmosphere makes accurate climate predictions very challenging, in particular with respect to extreme events. More detailed investigations of the underlying dynamics, such as the identification of the drivers regulating the energy exchange at the land surface and the quantification of fluxes between soil and atmosphere over different land types, are thus necessary. The recently started DROUGHT-HEAT project (funded by the European Research Council) aims to provide better understanding of the processes governing the land-atmosphere exchange. In the first phase of the project, different datasets and methods are used to investigate major drivers of land-atmosphere dynamics leading to droughts and heatwaves. In the second phase, these findings will be used for reducing uncertainties and biases in earth system models. Finally, the third part of the project will focus on the application of the previous findings and use them for the attribution of extreme events to land processes and possible mitigation through land geoengineering. One of the major questions in land-atmosphere exchange is the relationship between air temperature and soil moisture. Different studies show that especially during dry spells soil moisture has a strong impact on air temperature and the amplification of hot extremes. Whereas in dry and wet soil moisture regimes variations in latent heat flux during rain-free periods are expected to be small, this is not the case in transitional soil moisture regimes: Due to decreasing soil moisture content latent heat flux reduces with time, which causes in turn an increase in sensible heat flux and, subsequently, higher air temperatures. The investigation of air temperature evolution during dry spells can thus help to detect different soil moisture regimes and to provide insights on the effect of different soil moisture levels on air temperature. Here we assess the underlying relationships using different observational and

  13. Field Evidence for Optimal Acclimation of Leaf Nitrogen to Environmental Gradients

    NASA Astrophysics Data System (ADS)

    Dong, N.; Prentice, I. C. C.; Evans, B. J.; Retalic, S. C.; Lowe, A. J.; Wright, I. J.

    2015-12-01

    Nitrogen per unit leaf area (Narea) is a key variable in plant functional ecology and biogeochemistry. We hypothesized that Narea should be sum of a structural component proportional to leaf mass per area (LMA) and a metabolic component, predicted by optimality considerations to be proportional to irradiance while decreasing with air-to-leaf carbon dioxide drawdown (ci:ca) and temperature. The significant partial environmental and LMA effects on Narea that are both qualitatively and quantitatively supported this hypothesis by using LMA, leaf δ13C and Narea measurements on transcontinental transect in Australia. Trait gradient analysis revealed ci:ca to be perfectly plastic, while species turnover contributed about half the variation in LMA and Narea, consistent with a strong contribution of species turnover to the variation of these traits with environment. These findings motivate a hybrid leaf-economics approach to the prediction of Narea in ecosystem models.

  14. Dynamic Stiffness and Damping Characteristics of a High-Temperature Air Foil Journal Bearing

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; DellaCorte, Christopher; Valco, Mark J.; Prahl, Joseph M.; Heshmat, Hooshang

    2001-01-01

    Using a high-temperature optically based displacement measurement system, a foil air bearing's stiffness and damping characteristics were experimentally determined. Results were obtained over a range of modified Sommerfeld Number from 1.5E6 to 1.5E7, and at temperatures from 25 to 538 C. An Experimental procedure was developed comparing the error in two curve fitting functions to reveal different modes of physical behavior throughout the operating domain. The maximum change in dimensionless stiffness was 3.0E-2 to 6.5E-2 over the Sommerfeld Number range tested. Stiffness decreased with temperature by as much as a factor of two from 25 to 538 C. Dimensionless damping was a stronger function of Sommerfeld Number ranging from 20 to 300. The temperature effect on damping being more qualitative, showed the damping mechanism shifted from viscous type damping to frictional type as temperature increased.

  15. Impacts of rainfall and air temperature variations due to climate change upon hydrological characteristics: a case study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainfall and air temperature variations resulting from climate change are important driving forces to alter hydrologic processes in watershed ecosystems. This study investigated impacts of past and potential future rainfall and air temperature variations upon water discharge, water outflow (from th...

  16. Short-term Effects of Air Temperature on Blood Markers of Coagulation and Inflammation in Potentially Susceptible Individuals

    EPA Science Inventory

    Objectives: Changes in air temperature are associated with an increase in cardiovascular events, but the role of pro-coagulant and pro-inflammatory blood markers is still poorly understood. We investigated the association between air temperature and fibrinogen, plasminogen act...

  17. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    PubMed

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  18. Air pollution, lagged effects of temperature, and mortality: The Netherlands 1979-87.

    PubMed Central

    Mackenbach, J P; Looman, C W; Kunst, A E

    1993-01-01

    OBJECTIVE--To explore whether the apparent low threshold for the mortality effects of air pollution could be the result of confounding. DESIGN--The associations between mortality and sulphur dioxide (SO2) were analysed taking into account potential confounding factors. SETTING--The Netherlands, 1979-87. MEASUREMENTS AND MAIN RESULTS--The number of deaths listed by the day on which the death occurred and by the cause of death were obtained from the Netherlands Central Bureau of Statistics. Mortality from all causes and mortality from four large groups of causes (neoplasms, cardiovascular diseases, respiratory diseases, and external causes) were related to the daily levels of SO2 air pollution and potential confounders (available from various sources) using log-linear regression analysis. Variables considered as potential confounders were: average temperature; difference between maximum and minimum temperatures; amount of precipitation; air humidity; wind speed; influenza incidence; and calendar year, month, and weekday. Both lagged and unlagged effects of the meteorological and influenza variables were considered. Average temperature was represented by two variables--'cold', temperatures below 16.5 degrees C, and 'warm', those above 16.5 degrees C--to allow for the V shaped relation between temperature and mortality. The positive regression coefficient for the univariate effect of SO2 density on mortality from all causes dwindles to close to zero when all potential confounding variables are taken into account. The most important of these represents the lagged (one to five days) effect of low temperatures. Low temperatures have strong lagged effects on mortality, and often precede relatively high SO2 densities in the Netherlands. Results were similar for separate causes of death. While univariate associations suggest an effect of air pollution on mortality in all four cause of death groups, multivariate analyses show these effects, including that on mortality from

  19. On The Suitability of Air Temperature as a Predictive Tool for Lake Surface Temperature in a Changing Climate: A Case Study for Lake Tahoe, USA

    NASA Astrophysics Data System (ADS)

    Healey, N.; Piccolroaz, S.; Hook, S. J.; Toffolon, M.; Lenters, J. D.; Schladow, G.

    2015-12-01

    The ability to predict surface water temperature is essential toward understanding how future climate scenarios will impact inland water bodies such as lakes. Numerous predictive models have been developed to perform this task although many require inputs whose future model prediction is usually associated with large uncertainties, such as e.g., precipitation, cloudiness, wind and radiative fluxes. Conversely, air temperature is one of the most widely available variables in projections from Global Climate Models (GCMs). The predictive model air2water relies solely on air temperature data to predict lake surface temperature. The objective of this study is to demonstrate that air2water can be used as a predictive tool for climate change scenarios through a case study focused on Lake Tahoe, CA/NV, USA. Lake Tahoe has been selected due to extensive historical in-situ measurements that have been collected at that location since 1967 which we utilize to calibrate and validate air2water, and evaluate its performance. For model runs, we utilize different sources of air temperature data (buoys, land-based weather stations, GCMs) to establish how robustly air2water performs. We employ air temperature data from a combination of global gridded datasets including Climate Research Unit (CRU) TS3.21 (historical), and GCM output from the Coupled Model Intercomparison Project, Phase 5 (CMIP5) Community Climate System Model, version 4 (CCSM4) model (future) with representative concentration pathways of 4.5 and 8.5. Here, we present results from air2water predictions of the relationship between air and water temperature that demonstrate how this model is able to replicate trends on seasonal and interannual timescales. This finding shows promise toward understanding the impacts of future climate change on lakes and to expanding our study to lake surface temperatures globally.

  20. Pre-anthesis high-temperature acclimation alleviates damage to the flag leaf caused by post-anthesis heat stress in wheat.

    PubMed

    Wang, Xiao; Cai, Jian; Jiang, Dong; Liu, Fulai; Dai, Tingbo; Cao, Weixing

    2011-04-15

    The objective of this study was to investigate the effect of pre-anthesis high-temperature acclimation on leaf physiology of winter wheat in response to post-anthesis heat stress. The results showed that both pre- and post-anthesis heat stresses significantly depressed flag leaf photosynthesis and enhanced cell membrane peroxidation, as exemplified by increased O₂⁻(·) production rate and reduction in activities of antioxiditave enzymes. However, under post-anthesis heat stress, plants with pre-anthesis high-temperature acclimation (HH) showed much higher photosynthetic rates than those without pre-anthesis high-temperature acclimation (CH). Leaves of HH plants exhibited a higher Chl a/b ratio and lower chlorophyll/carotenoid ratio and superoxide anion radical release rate compared with those of the CH plants. In addition, antioxidant enzyme activities in HH plants were significantly higher than in CH. Coincidently, expressions of photosythesis-responsive gene encoding Rubisco activase B (RcaB) and antioxidant enzyme-related genes encoding mitochondrial manganese superoxide dismutase (Mn-SOD), chloroplastic Cu/Zn superoxide dismutase (Cu/Zn-SOD), catalase (CAT) and cytosolic glutathione reductase (GR) were all up-regulated under HH, whereas a gene encoding a major chlorophyll a/b-binding protein (Cab) was up-regulated by post-anthesis heat stress at 10 DAA, but was down-regulated at 13 DAA. The changes in the expression levels of the HH plants were more pronounced than those for the CH. Collectively, the results indicated that pre-anthesis high-temperature acclimation could effectively alleviate the photosynthetic and oxidative damage caused by post-anthesis heat stress in wheat flag leaves, which was partially attributable to modifications in the expression of the photosythesis-responsive and antioxidant enzymes-related genes.

  1. 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).

  2. 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

  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.

  4. A hierarchical model of daily stream temperature u