Science.gov

Sample records for 1-gwh diurnal load-leveling

  1. Wire rope superconducting cable for diurnal load leveling SMES

    SciTech Connect

    Costello, G.A.

    1980-01-01

    The design of a wire rope cable for a superconducting magnetic energy storage (SMES) unit is discussed. The superconducting wires in the rope permit the passage of large currents in the relatively small conductors of the windings and hence cause large electromagnetic forces to act on the rope. The diameter of the rope, from a strength point of view, can be considerably reduced by supporting the rope at various points along its length.

  2. Diurnal Cycle Computations

    SciTech Connect

    Covey, Curt; Doutriaux, Charles

    2016-12-01

    Directory /export_backup/covey1/CMIP5/Precipitation/DiurnalCycle/GridpointTimeseries/CMCCBCM_etal/ on crunchy.llnl.gov contains Python / UV-CDAT scripts compositeDiurnalStatistics.py and fourierDiurB nalAllGrid.py. compositeDiurnalStatistics.py reads high-time-frequency climate data from one or more years and computes 24 hour composite-mean and composite-standard-deviation cycles for one requested month.

  3. A high rate clarifier for load levelling in sewerage systems.

    PubMed

    Jago, R A; Davey, A; Li, H

    2003-01-01

    The combining of chemically assisted clarification with a proprietary physical separation technology has led to a high rate process for clarifying flocculated sewage and other waste streams. This hybrid physico-chemical system, known as the CDS Fine Solids Separation (FSS) System, was developed over a two year period within a sewage treatment plant environment. This paper summarises the results of a recent field trial of the system with a Victorian water authority which experiences heavy loading of sewers in a coastal town during holiday periods. The trial sought to evaluate the FSS as a tool for smoothing the load on the 11 km long sewer to the sewage treatment plant (STP). The FSS system could possibly enable the costly augmentation of the sewer to be deferred, particularly as the capacity of the existing sewer pipe is satisfactory for most of the year. Water quality parameters were determined for a range of flowrates and operational conditions over a two month period. Large reductions were achieved in TSS, TP, FC, turbidity and BOD5, with only minimal reductions in NH3 and TON. These results showed that the FSS could meet the authority's objectives for load levelling and would provide a 20-25% increase in effective sewer capacity. The data are also discussed in terms of possible use of the effluent from the FSS for water reuse applications.

  4. Hydride generation from the Exide load-leveling cells

    NASA Astrophysics Data System (ADS)

    Marr, J. J.; Smaga, J. A.

    1987-05-01

    Stibine and arsine evolution from lead-acid cells in a 36-kWh Exide load-leveling module was measured as this module approached 1900 cycles of operation. A gas-collection apparatus enabled us to determine the maximum and average rates for evolution of both toxic hydrides. Hydride generation began once the cell voltage exceeded 2.4 V. The maximum rate for arsine occurred just above 2.5 V and consistently preceded the peak rate for stibine for each sampled cell. The average rates of hydride generation were found to be 175 g/min for stibine and 12.6 g/min for arsine. The former rate proved to be the critical value in determining safe ventilation requirements for cell off-gases. The minimum airflow requirement was calculated to be 340 L/min per cell. Projections for a hypothetical 1-MWh Exide battery without an abatement system indicated that the normal ventilation capacity in the Battery Energy Storage Test facility provides nearly five times the airflow needed for safe hydride removal.

  5. Thermal load leveling during silicon crystal growth from a melt using anisotropic materials

    DOEpatents

    Carlson, Frederick M.; Helenbrook, Brian T.

    2016-10-11

    An apparatus for growing a silicon crystal substrate comprising a heat source, an anisotropic thermal load leveling component, a crucible, and a cold plate component is disclosed. The anisotropic thermal load leveling component possesses a high thermal conductivity and may be positioned atop the heat source to be operative to even-out temperature and heat flux variations emanating from the heat source. The crucible may be operative to contain molten silicon in which the top surface of the molten silicon may be defined as a growth interface. The crucible may be substantially surrounded by the anisotropic thermal load leveling component. The cold plate component may be positioned above the crucible to be operative with the anisotropic thermal load leveling component and heat source to maintain a uniform heat flux at the growth surface of the molten silicon.

  6. The tropical cyclone diurnal cycle

    NASA Astrophysics Data System (ADS)

    Dunion, Jason P.

    The research presented in this thesis explores a phenomenon referred to as the tropical cyclone (TC) diurnal cycle (TCDC) and presents satellite, numerical modeling, and observational perspectives pertaining to how it can be monitored, its evolution in time and space, its relevance to TC structure and intensity, and how it manifests in numerical simulations of TCs. Infrared satellite imagery was developed and used to investigate diurnal oscillations in TCs and finds a diurnal pulsing pattern that occurs with notable regularity through a relatively deep layer from the inner core to the surrounding environment. A combination of satellite, numerical model simulations, and aircraft observations found diurnal signals in operationally analyzed radii of 50 kt winds in TCs and in satellite intensity estimates from the Advanced Dvorak Technique and spawned the development of a 24-hr conceptual clock that approximates the temporal and spatial evolution of the TCDC each day. TC diurnal pulses are revealed to significantly impact the thermodynamics and winds in the TC environment and appear as narrow, convectively active rings of high radar reflectivity in NOAA aircraft radar data and are hundreds of kilometers in length. Enhanced nighttime radiational cooling that is particularly favored in the TC outflow layer acts to pre-condition the TC environment in a way that favors triggering of the TCDC and TC diurnal pulses, while in the daytime, the stabilizing effects of shortwave warming begins to suppress TCDC processes in the storm, leading to the culmination of the TCDC each day. Schematics are presented that summarize many of the main findings in this work, including descriptions of the basic state of the TC environment as the TCDC evolves during its early and later stages each day and a TCDC-centric daytime evolution of a TC diurnal pulse, associated squall lines and gust fronts, and radial and vertical winds in the lower and upper levels of the storm. The TCDC represents a

  7. Knowledge-based load leveling and task allocation in human-machine systems

    NASA Technical Reports Server (NTRS)

    Chignell, M. H.; Hancock, P. A.

    1986-01-01

    Conventional human-machine systems use task allocation policies which are based on the premise of a flexible human operator. This individual is most often required to compensate for and augment the capabilities of the machine. The development of artificial intelligence and improved technologies have allowed for a wider range of task allocation strategies. In response to these issues a Knowledge Based Adaptive Mechanism (KBAM) is proposed for assigning tasks to human and machine in real time, using a load leveling policy. This mechanism employs an online workload assessment and compensation system which is responsive to variations in load through an intelligent interface. This interface consists of a loading strategy reasoner which has access to information about the current status of the human-machine system as well as a database of admissible human/machine loading strategies. Difficulties standing in the way of successful implementation of the load leveling strategy are examined.

  8. Diurnal patterns of blowing sand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diurnal pattern of blowing sand results from a complex process that involves the interaction between the sun, wind, and earth. During the day, solar heating produces thermal instability, which enhances the convective mixing of high momentum winds from the upper levels of the atmosphere to the s...

  9. Hydrogen generation and utility load leveling system and the method therefor

    SciTech Connect

    Parker, R.Z.; Hanrahan, R.J.; Gupta, A.K.

    1993-06-15

    A continuous method of providing load leveling and hydrogen and oxygen production from one system is described comprising the steps of: electrolyzing concentrated hydrohalic acid into hydrogen, halogen and dilute hydrohalic acid; photochemically and thermally reacting water with said halogen to produce hydrogen halide and oxygen; separating said oxygen from said hydrogen halide; and producing concentrated hydrohalic acids by solvating said hydrogen halide with dilute hydrohalic acid, wherein said system utilizes a cell having a charging current density and a discharging current density. A method of producing molecular hydrogen and halogens from hydrohalic acid in solution with transition metal halide complexes is described comprising: using photolytic energy to excite a transition metal halide complex in solution with a hydrohalic acid, causing a metal ion-ligand to be photochemically reduced to a lower oxidation state, and halide ions to be oxidized to molecular halogen; continuously removing said molecular halogen from the presence of the photolytic reaction; and using electrical energy to electrolyze said photochemically reduced, transition metal halide complexes in solution with said hydrohalic acid, causing said metal ion-ligand to be electrolytically oxidized to a higher oxidation state of that species, and hydrogen ions to be reduced to molecular hydrogen. A continuous load leveling and hydrogen and oxygen production system is described for accomplishing the above.

  10. Development of Zinc/Bromine Batteries for Load-Leveling Applications: Phase 1 Final Report

    SciTech Connect

    Eidler, Phillip

    1999-07-01

    The Zinc/Bromine Load-Leveling Battery Development contract (No. 40-8965) was partitioned at the outset into two phases of equal length. Phase 1 started in September 1990 and continued through December 1991. In Phase 1, zinc/bromine battery technology was to be advanced to the point that it would be clear that the technology was viable and would be an appropriate choice for electric utilities wishing to establish stationary energy-storage facilities. Criteria were established that addressed most of the concerns that had been observed in the previous development efforts. The performances of 8-cell and 100-cell laboratory batteries demonstrated that the criteria were met or exceeded. In Phase 2, 100-kWh batteries will be built and demonstrated, and a conceptual design for a load-leveling plant will be presented. At the same time, work will continue to identify improved assembly techniques and operating conditions. This report details the results of the efforts carried out in Phase 1. The highlights are: (1) Four 1-kWh stacks achieved over 100 cycles, One l-kWh stack achieved over 200 cycles, One 1-kWh stack achieved over 300 cycles; (2) Less than 10% degradation in performance occurred in the four stacks that achieved over 100 cycles; (3) The battery used for the zinc loading investigation exhibited virtually no loss in performance for loadings up to 130 mAh/cm{sup 2}; (4) Charge-current densities of 50 ma/cm{sup 2} have been achieved in minicells; (5) Fourteen consecutive no-strip cycles have been conducted on the stack with 300+ cycles; (6) A mass and energy balance spreadsheet that describes battery operation was completed; (7) Materials research has continued to provide improvements in the electrode, activation layer, and separator; and (8) A battery made of two 50-cell stacks (15 kWh) was produced and delivered to Sandia National Laboratories (SNL) for testing. The most critical development was the ability to assemble a battery stack that remained leak free. The

  11. Upper Limb Muscle and Brain Activity in Light Assembly Task on Different Load Levels

    NASA Astrophysics Data System (ADS)

    Zadry, Hilma Raimona; Dawal, Siti Zawiah Md.; Taha, Zahari

    2010-10-01

    A study was conducted to investigate the effect of load on upper limb muscles and brain activities in light assembly task. The task was conducted at two levels of load (Low and high). Surface electromyography (EMG) was used to measure upper limb muscle activities of twenty subjects. Electroencephalography (EEG) was simultaneously recorded with EMG to record brain activities from Fz, Pz, O1 and O2 channels. The EMG Mean Power Frequency (MPF) of the right brachioradialis and the left upper trapezius activities were higher on the high-load task compared to low-load task. The EMG MPF values also decrease as time increases, that reflects muscle fatigue. Mean power of the EEG alpha bands for the Fz-Pz channels were found to be higher on the high-load task compared to low-load task, while for the O1-O2 channels, they were higher on the low-load task than on the high-load task. These results indicated that the load levels effect the upper limb muscle and brain activities. The high-load task will increase muscle activities on the right brachioradialis and the left upper tapezius muscles, and will increase the awareness and motivation of the subjects. Whilst the low-load task can generate drowsiness earlier. It signified that the longer the time and the more heavy of the task, the subjects will be more fatigue physically and mentally.

  12. A system-level mathematical model for evaluation of power train performance of load-leveled electric-vehicles

    NASA Technical Reports Server (NTRS)

    Purohit, G. P.; Leising, C. J.

    1984-01-01

    The power train performance of load leveled electric vehicles can be compared with that of nonload leveled systems by use of a simple mathematical model. This method of measurement involves a number of parameters including the degree of load leveling and regeneration, the flywheel mechanical to electrical energy fraction, and efficiencies of the motor, generator, flywheel, and transmission. Basic efficiency terms are defined and representative comparisons of a variety of systems are presented. Results of the study indicate that mechanical transfer of energy into and out of the flywheel is more advantageous than electrical transfer. An optimum degree of load leveling may be achieved in terms of the driving cycle, battery characteristics, mode of mechanization, and the efficiency of the components. For state of the art mechanically coupled flyheel systems, load leveling losses can be held to a reasonable 10%; electrically coupled systems can have losses that are up to six times larger. Propulsion system efficiencies for mechanically coupled flywheel systems are predicted to be approximately the 60% achieved on conventional nonload leveled systems.

  13. Conceptual designs for utility load-leveling battery with Li/FeS cells

    SciTech Connect

    Zivi, S. M.; Kacinskas, H.; Pollack, I.; Chilenskas, A. A.; Grieve, W.; McFarland, B. L.; Sudar, S.

    1980-07-01

    In 1978, a conceptual design of a 100 MW-h load-leveling battery system having Li alloy/FeS cells was developed as a result of a joint effort between ANL and Rockwell International. In this conceptual design, the submodule, which was the basic replaceable unit for the system, had a capacity of 240 kW-h and consisted of ninety-six 2.5 kW-h cells. However, a study by Rockwell indicated that the cost for battery hardware, $60 to 80/kW-h (cells and converters not included), was too high. Most of this cost was contributed by the submodule structure and the charge equalization scheme, which was the same as that developed for electric-vehicle batteries. In 1979, subsequent efforts were concentrated on lowering these hardware costs and resulted in the development of three modified designs, which are presented in this report. The first, developed at ANL, consisted of a 30 kW-h cell/submodule and the electric-vehicle equalization scheme. The hardware cost for this modified design was quite low, about $25/kW-h; however, this design was eventually rejected owing to the apparent impracticality of such a large cell. The two other modified designs had more conservative cell designs. One of them, developed at ANL, consisted of a 120 kW-h submodule consisting of one hundred 1.2 kW-h cells; the other, developed at Rockwell, consisted of a 1020 kW-h submodule consisting of four hundred and eight 2.5 kW-h cells. For both of these designs, an alternative method of equalization, in which fixed resistance shunts are used on each cell, was proposed; this equalization method adds little equipment cost to the system and only sacrifices about 4% of the coulombic and energy efficiencies. The cost of battery hardware for these two designs was estimated to be acceptable, about $22 to 60/kW-h. Some questions remain on the assumed capabilities of the cells and the feasibility of the battery hardware.

  14. Diurnal and semi-diurnal temperature variability of the middle atmosphere, as observed by ISAMS

    NASA Astrophysics Data System (ADS)

    Dudhia, A.; Smith, S. E.; Wood, A. R.; Taylor, F. W.

    1993-06-01

    Some preliminary results are presented showing that the ISAMS instrument on board the UARS satellite has detected sun-synchronous variations in atmospheric temperature between 15-80 km altitude. These are interpreted as the westward-migrating diurnal and semi-diurnal tides. Zonal mean maps of the amplitudes of these components are shown, determined from 40 days' observations during the northern hemisphere winter of 1991/92. The results show maximum amplitudes ˜5 K, with the diurnal tide strongest over the equator while the semi-diurnal tide is strongest at mid-latitudes. Comparisons are made with previous observations from the LIMS instrument and the lidar at Biscarrosse, France. While the ISAMS and LIMS results are consistent, several significant differences from the lidar results are noted. The conclusion is that information on the global diurnal and semi-diurnal temperature tides in the middle atmosphere may be obtained from a relatively simple treatment of ISAMS data.

  15. Diurnal variations of vegetation canopy structure

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Kirchner, J. A.

    1983-01-01

    The significance and magnitude of diurnal variations of vegetation canopy structure are reviewed. Diurnal leaf inclination-azimuth angle distributions of a soybean and cotton canopy were documented using a simple measurement technique. The precision of the measurements was on the order of + or -5 deg for the inclination and + or -14 deg for the azimuth. The experimental results and a review of the literature showed that this distribution can vary significantly on a diurnal basis due to vegetation type, heliotropic leaf movement, environmental conditions, and vegetation stress. The study also showed that it is erroneous to treat two separate distributions of azimuth and inclination angles rather than one three-dimensional distribution of leaf orientation. The latter distribution needs to be routinely collected in studies which document variations of diurnal spectral reflectance with changes in solar zenith angle.

  16. Diurnal Cycle of Convection during Dynamo

    NASA Astrophysics Data System (ADS)

    Ciesielski, P. E.; Johnson, R. H.

    2014-12-01

    During the special observing period (SOP) of the DYNAMO/CINDY/AMIE field campaign, conducted over the Indian Ocean from October to November 2011, two sounding networks, one north and one south of the equator, took 4-8 soundings/day. This dataset with 3-hr time resolution offers a unique opportunity to investigate the diurnal cycle of Intertropical Convergence Zone (ITCZ) convection which was present within the southern sounding array (SSA) for extended periods during the SOP. For example, during the first half of October 2011 when the ITCZ was located between 3°S and 8°S, TRMM 3B42 3-h rainfall averaged over the SSA exhibited a prominent diurnal cycle with a late night/early morning maximum and an early evening minimum. The rainfall diurnal range during this period over the SSA was 4.8 mm which was ~50% of the daily mean (10.1 mm). Mean rainfall over the northern sounding array was much lighter (0.9 mm) during this period with a diurnal cycle nearly out of phase with that over the SSA. Using primarily sounding and satellite data, we will explore the characteristics of this diurnally varying convection and what, if any, influence it may have had on the Madden-Julian Oscillation (MJO) signal.

  17. Diurnal Variations in Maximal Oxygen Uptake.

    ERIC Educational Resources Information Center

    McClellan, Powell D.

    A study attempted to determine if diurnal (daily cyclical) variations were present during maximal exercise. The subjects' (30 female undergraduate physical education majors) oxygen consumption and heart rates were monitored while they walked on a treadmill on which the grade was raised every minute. Each subject was tested for maximal oxygen…

  18. Short-term bulk energy storage system scheduling for load leveling in unit commitment: modeling, optimization, and sensitivity analysis.

    PubMed

    Hemmati, Reza; Saboori, Hedayat

    2016-05-01

    Energy storage systems (ESSs) have experienced a very rapid growth in recent years and are expected to be a promising tool in order to improving power system reliability and being economically efficient. The ESSs possess many potential benefits in various areas in the electric power systems. One of the main benefits of an ESS, especially a bulk unit, relies on smoothing the load pattern by decreasing on-peak and increasing off-peak loads, known as load leveling. These devices require new methods and tools in order to model and optimize their effects in the power system studies. In this respect, this paper will model bulk ESSs based on the several technical characteristics, introduce the proposed model in the thermal unit commitment (UC) problem, and analyze it with respect to the various sensitive parameters. The technical limitations of the thermal units and transmission network constraints are also considered in the model. The proposed model is a Mixed Integer Linear Programming (MILP) which can be easily solved by strong commercial solvers (for instance CPLEX) and it is appropriate to be used in the practical large scale networks. The results of implementing the proposed model on a test system reveal that proper load leveling through optimum storage scheduling leads to considerable operation cost reduction with respect to the storage system characteristics.

  19. Short-term bulk energy storage system scheduling for load leveling in unit commitment: modeling, optimization, and sensitivity analysis

    PubMed Central

    Hemmati, Reza; Saboori, Hedayat

    2016-01-01

    Energy storage systems (ESSs) have experienced a very rapid growth in recent years and are expected to be a promising tool in order to improving power system reliability and being economically efficient. The ESSs possess many potential benefits in various areas in the electric power systems. One of the main benefits of an ESS, especially a bulk unit, relies on smoothing the load pattern by decreasing on-peak and increasing off-peak loads, known as load leveling. These devices require new methods and tools in order to model and optimize their effects in the power system studies. In this respect, this paper will model bulk ESSs based on the several technical characteristics, introduce the proposed model in the thermal unit commitment (UC) problem, and analyze it with respect to the various sensitive parameters. The technical limitations of the thermal units and transmission network constraints are also considered in the model. The proposed model is a Mixed Integer Linear Programming (MILP) which can be easily solved by strong commercial solvers (for instance CPLEX) and it is appropriate to be used in the practical large scale networks. The results of implementing the proposed model on a test system reveal that proper load leveling through optimum storage scheduling leads to considerable operation cost reduction with respect to the storage system characteristics. PMID:27222741

  20. 40 CFR 86.133-96 - Diurnal emission test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... (p) For the supplemental two-diurnal test sequence described in § 86.130-96, the following steps... minutes, respectively, after the initial sampling. (3) This completes the supplemental two-diurnal test... the supplemental two-diurnal test sequence, as described in § 86.130-96. (2) For the full...

  1. 40 CFR 86.133-96 - Diurnal emission test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... (p) For the supplemental two-diurnal test sequence described in § 86.130-96, the following steps... minutes, respectively, after the initial sampling. (3) This completes the supplemental two-diurnal test... the supplemental two-diurnal test sequence, as described in § 86.130-96. (2) For the full...

  2. 40 CFR 86.133-96 - Diurnal emission test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... (p) For the supplemental two-diurnal test sequence described in § 86.130-96, the following steps... minutes, respectively, after the initial sampling. (3) This completes the supplemental two-diurnal test... the supplemental two-diurnal test sequence, as described in § 86.130-96. (2) For the full...

  3. Climate Implications of the Moist-convective Diurnal Cycle

    NASA Astrophysics Data System (ADS)

    Ruppert, James

    2016-04-01

    This idealized modeling study is provoked by recent observations from the tropical Indian Ocean (the DYNAMO field campaign), which demonstrate the high degree to which column humidity is modulated by the diurnal cycle of clouds. Under suppressed large-scale conditions, shallow convection prevails, and the diurnal cycles of shortwave radiative heating and sea surface temperature (SST) are at their strongest. In turn, the diurnal cycle of clouds is prominent, which is manifest in daytime cloud deepening and tropospheric moistening in response to boundary layer warming (bearing resemblance to the diurnal cycle over land). An idealized modeling study is performed to 1) assess the driving processes in the diurnal cycle (i.e., SST vs. radiative forcing) and 2) assess whether or not this diurnal cycle rectifies onto longer timescales. A cloud-resolving model framework is employed with the CM1 model (Bryan and Fritsch 2002), wherein a diurnal cycle of SST is prescribed, fully-interactive radiation varies diurnally, and the weak temperature gradient (WTG) approximation is invoked to simulate the feedbacks between the moist convection and large-scale circulation. The results suggest that the diurnal cycle is highly nonlinear, in that the diurnal fluctuation of clouds strongly rectifies onto longer timescales. The diurnal cycle must therefore be regarded as a "forcing mechanism" to the climate system. The vitality and quality of the moist-convective diurnal cycle in climate models may in turn be important to the accuracy of their simulations.

  4. Reference design of 100 MW-h lithium/iron sulfide battery system for utility load leveling

    SciTech Connect

    Zivi, S.M.; Kacinskas, H.; Pollack, I.; Chilenskas, A.A.; Barney, D.L.; Grieve, W.; McFarland, B.L.; Sudar, S.; Goldstein, E.; Adler, E.

    1980-03-01

    The first year in a two-year cooperative effort between Argonne National Laboratory and Rockwell International to develop a conceptual design of a lithium alloy/iron sulfide battery for utility load leveling is presented. A conceptual design was developed for a 100 MW-h battery system based upon a parallel-series arrangement of 2.5 kW-h capacity cells. The sales price of such a battery system was estimated to be very high, $80.25/kW-h, exclusive of the cost of the individual cells, the dc-to-ac converters, site preparation, or land acquisition costs. Consequently, the second year's efforts were directed towards developing modified designs with significantly lower potential costs.

  5. Observations of the diurnal tide from space

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.; Wu, D. L.; Burrage, M. D.; Gell, D. A.; Grassl, H. J.; Lieberman, R. S.; Marshall, A. R.; Morton, Y. T.; Ortland, D. A.; Skinner, W. R.

    1994-01-01

    This study presents a climatology of mesospheric and lower-thermospheric diurnal tidal winds obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS). The observations reveal that although tidal structures are present at all times, like the prevailing zonal winds, they exhibit significant semiannual as well as other shorter-term variations in amplitude. Results are presented for a period extending over more than one year from November 1991 to July 1993. The 1,1 diurnal tidal amplitude of the meridional component, characterized by the value at an altitude of 90 km and a latitude of 22 deg, ranges from a minimum at solstice of less than 20 m per sec to an equinox maximum of over 70 m per sec. The vertical wavelength and phase of the tide show only slight variations throughout the year, with a suggestion of semiannual variations in both.

  6. Diurnal Variations of Clouds in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Wu, Qiaoyan; Ruan, Zhenxin

    2016-04-01

    Using 14 years (2000-2013) of pixel-resolution infrared (IR) brightness temperature data and best track data, this study estimates the diurnal variations of convective systems in tropical cyclones (TCs) in the western North Pacific. The very cold cloud cover (IR brightness temperatures < 208 K) of TCs reaches a maximum areal extent in the early morning (0000-0300 LST) and then decreases after the sunrise. The decrease of very cold cloud cover is followed by an increase of cloud cover between 208 K and 240 K with a maximum areal extent in the afternoon (1500-1800 LST). TC IR cloud top temperatures < 240 K have minimum values in the morning (0300-0600 LST) , while TC IR cloud top temperatures > 240 K have mean minimum values in the afternoon (1500-1800 LST). The out-of-phase relation between different cloud conditions with IR cloud top temperatures < 240 K and IR cloud top temperatures > 240 K lead to radius-averaged IR temperature show two minima within a day. Different diurnal evolution under different cloud conditions suggests that TC convective systems are better described in terms of both areal extent and cloud-top temperature. The maximum cloud cover with IR cloud top temperatures colder than 208 K in the morning and the maximum cloud cover with IR cloud top temperatures between 208 K and 240 K in the afternoon suggest that two different mechanisms might be involved with the diurnal variations of these two types of TC cloud conditions.

  7. Diurnal ocean surface layer model validation

    NASA Technical Reports Server (NTRS)

    Hawkins, Jeffrey D.; May, Douglas A.; Abell, Fred, Jr.

    1990-01-01

    The diurnal ocean surface layer (DOSL) model at the Fleet Numerical Oceanography Center forecasts the 24-hour change in a global sea surface temperatures (SST). Validating the DOSL model is a difficult task due to the huge areas involved and the lack of in situ measurements. Therefore, this report details the use of satellite infrared multichannel SST imagery to provide day and night SSTs that can be directly compared to DOSL products. This water-vapor-corrected imagery has the advantages of high thermal sensitivity (0.12 C), large synoptic coverage (nearly 3000 km across), and high spatial resolution that enables diurnal heating events to be readily located and mapped. Several case studies in the subtropical North Atlantic readily show that DOSL results during extreme heating periods agree very well with satellite-imagery-derived values in terms of the pattern of diurnal warming. The low wind and cloud-free conditions necessary for these events to occur lend themselves well to observation via infrared imagery. Thus, the normally cloud-limited aspects of satellite imagery do not come into play for these particular environmental conditions. The fact that the DOSL model does well in extreme events is beneficial from the standpoint that these cases can be associated with the destruction of the surface acoustic duct. This so-called afternoon effect happens as the afternoon warming of the mixed layer disrupts the sound channel and the propagation of acoustic energy.

  8. Process modeling of ICU patient flow: effect of daily load leveling of elective surgeries on ICU diversion.

    PubMed

    Kolker, Alexander

    2009-02-01

    Despite the considerable number of publications on ICU patient flow and analysis of its variability, a basic and practically important question remained unanswered: what maximum number of elective surgeries per day should be scheduled (along with the competing demand from emergency surgeries) in order to reduce diversion in an ICU with fixed bed capacity to an acceptable low level, or prevent it at all? The goal of this work was to develop a methodology to answer this question. An ICU patient flow simulation model was developed to establish a quantitative link between the daily load leveling of elective surgeries (elective schedule smoothing) and ICU diversion. It was demonstrated that by scheduling not more than four elective surgeries per day ICU diversion due to 'no ICU beds' would be practically eliminated. However this would require bumping 'extra' daily surgeries to the block time day of another week which could be up to 2 months apart. Because not all patients could wait that long for their elective surgery, another more practical scenario was tested that would also result in a very low ICU diversion: bumping 'extra' daily elective surgeries within less than 2 weeks apart, scheduling not more than five elective surgeries per day, and strict adherence to the ICU admission/ discharge criteria.

  9. Diurnal measurements with prototype CMOS Omega receivers

    NASA Technical Reports Server (NTRS)

    Burhans, R. W.

    1976-01-01

    Diurnal signals from eight omega channels have been monitored at 10.2 KHz for selected station pairs. All eight Omega stations have been received at least 50 percent of the time over a 24 hour period during the month of October 1976. The data presented confirm the expected performance of the CMOS omega sensor processor in being able to digsignals out of a noisy environment. Of particular interest are possibilities for use of antipodal reception phenomena and a need for some ways of correcting for multi-modal propagation effects.

  10. Diurnal Curve of the Ocular Perfusion Pressure

    PubMed Central

    Moreira, TCA; Bezerra, BSP; Vianello, MP; Corradi, J; Dorairaj, SK; Prata, TS

    2016-01-01

    ABSTRACT Purpose: To describe the diurnal variation of the ocular perfusion pressure (OPP) in normal, suspects and glaucoma patients. Materials and methods: Seventy-nine subjects were enrolled in a prospective study. The diurnal curve of intraocular pressure (IOP) was performed and blood pressure measurements were obtained. Each participant was grouped into one of the following based upon the clinical evaluation of the optic disk, IOP and standard achromatic perimetry (SAP): 18 eyes were classified as normal (normal SAP, normal optic disk evaluation and IOP < 21 mm Hg in two different measurements), 30 eyes as glaucoma suspect (GS) (normal SAP and mean deviation (MD), C/D ration > 0.5 or asymmetry > 0.2 and/or ocular hypertension), 31 eyes as early glaucoma (MD < -6 dB, glaucomatous optic neuropathy and SAP and MDs on SAP. Standard achromatic perimetry was performed with the Octopus 3.1.1 Dynamic 24-2 program. Intraocular pressure and blood pressure measurements were taken at 6 am, 9 am, 12, 3 and 6 pm. The patients stayed in the seated position for 5 minutes prior to blood pressure measurements. Results: The mean IOP values in all groups did not follow any regular pattern. The peak IOP was found to be greater in suspect [18.70 ± 3.31 (mm Hg ± SD)] and glaucoma (18.77 ± 4.30 mm Hg) patients as compared to normal subjects (16.11 ± 2.27 mm Hg). In studying the diurnal variation of the OPP, we found lower values at 3 pm in normals (34.21 ± 2.07 mm Hg), at 9 am in suspects (54.35 ± 3.32 mm Hg) and at 12 pm in glaucoma patients (34.84 ± 1.44 mm Hg). Conclusion: Each group has a specific OPP variation during the day with the most homogeneous group being the suspect one. It is important to keep studying the IOP and OPP variation for increased comprehension of the pathophysiology of glaucomatous optic neuropathy. How to cite this article: Kanadani FN, Moreira TCA, Bezerra BSP, Vianello MP, Corradi J, Dorairaj SK, Prata TS. Diurnal Curve of the Ocular Perfusion

  11. In situ observations of diurnal warming at the ocean surface

    NASA Astrophysics Data System (ADS)

    Gentemann, C. L.; Minnett, P. J.

    2007-05-01

    Observations of diurnal temperature variability at the ocean surface have been primarily available only from satellite SST retrievals themselves. Since most satellite observations revisit the same location only infrequently, determining how the ocean surface diurnal heating responds to variability in forcing (mainly insolation and wind speed) has been primarily addressed through theoretical modeling or extrapolation of results from in situ (buoy) observations measured 0.5 m to 1.5 m below the skin layer. Diurnal heating in the skin layer may be quite different than heating at 0.5 m as this layer responds very rapidly to changes in heat and momentum. The Explorer of the Seas, a cruise ship, makes weekly cruises on two alternating tracks through the Caribbean Sea. Measurements from the Marine Atmospheric Emitted Radiance Interferometer (M-AERI) carried on the Explorer of the Seas provide one of the few skin SST data sets, along with ancillary measurements necessary for diurnal investigations. Initial analyses show that the surface signature of diurnal warming in the skin layer is chiefly controlled by the wind speed. The daily peak in diurnal warming is directly related to the minimum wind speed during the day, causing the time of the peak to shift depending on when the minimum winds occur. Fluctuations in wind speed can result in multiple peaks in diurnal heating during a single afternoon. Wind speed is negatively lag-correlated with diurnal warming while insolation is positively lag-correlated. The maximum lag-correlation of wind speed (insolation) with diurnal warming is at a time lag of 30 (50) minutes. Several models of diurnal variability exist. A comparison of several models with each other reveals considerable differences in estimates of diurnal warming. Further validation of the models using M-AERI observed diurnal warming again reveals considerable differences in estimates of warming related to model forcing parameterizations.

  12. Diurnal tides in the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Kowalik, Z.; Proshutinsky, A. Y.

    1993-01-01

    A 2D numerical model with a space grid of about 14 km is applied to calculate diurnal tidal constituents K(1) and O(1) in the Arctic Ocean. Calculated corange and cotidal charts show that along the continental slope, local regions of increased sea level amplitude, highly variable phase and enhanced currents occur. It is shown that in these local regions, shelf waves (topographic waves) of tidal origin are generated. In the Arctic Ocean and Northern Atlantic Ocean more than 30 regions of enhanced currents are identified. To prove the near-resonant interaction of the diurnal tides with the local bottom topography, the natural periods of oscillations for all regions have been calculated. The flux of energy averaged over the tidal period depicts the gyres of semitrapped energy, suggesting that the shelf waves are partially trapped over the irregularities of the bottom topography. It is shown that the occurrence of near-resonance phenomenon changes the energy flow in the tidal waves. First, the flux of energy from the astronomical sources is amplified in the shelf wave regions, and afterwards the tidal energy is strongly dissipated in the same regions.

  13. Diurnal Variation of Martian Dust Opacity

    NASA Astrophysics Data System (ADS)

    Martin, T. Z.; Tamppari, L. K.

    2005-08-01

    Recent MER Spirit rover observations of dust devils crossing the plains of Gusev crater demonstrate the similarity of that Martian desert to terrestrial sites. Near-surface thermal contrast builds during the day and promotes growth of dust- raising vortices. Evidence for corresponding transient thermal behavior has been shown in MER MiniTES profiles. How prevalent is such dust activity? Is the raised dust sufficient to modify the column dust opacity? The answers have implications for mission operations as well as for atmospheric science. We have expanded the scope of diurnal dust monitoring by going back to Viking Orbiter IR Thermal Mapper data, for which highly elliptical orbits gave good diurnal coverage (Martin, T., Icarus 45, p. 427, 1981). We examine the Spirit site and equatorial regions of similar surface character. Dust opacity is inferred from IRTM data by comparing brightness temperature within the 6-8 um range (T7), as continuum, with that in the 8-10 um band (T9), where silicate dust absorption and emission is stronger. During the daytime, when the surface is warmer than overlying dust, the spectral contrast in these two bands allows computation of opacity if a thermal profile is assumed. This research was funded by the JPL Research and Technology development program and carried out by the Jet Propulsion Laboratory, California Institute of Technology.

  14. How snowpack heterogeneity affects diurnal streamflow timing

    USGS Publications Warehouse

    Lundquist, J.D.; Dettinger, M.D.

    2005-01-01

    Diurnal cycles of streamflow in snow-fed rivers can be used to infer the average time a water parcel spends in transit from the top of the snowpack to a stream gauge in the river channel. This travel time, which is measured as the difference between the hour of peak snowmelt in the afternoon and the hour of maximum discharge each day, ranges from a few hours to almost a full day later. Travel times increase with longer percolation times through deeper snowpacks, and prior studies of small basins have related the timing of a stream's diurnal peak to the amount of snow stored in a basin. However, in many larger basins the time of peak flow is nearly constant during the first half of the melt season, with little or no variation between years. This apparent self-organization at larger scales can be reproduced by employing heterogeneous observations of snow depths and melt rates in a model that couples porous medium flow through an evolving snowpack with free surface flow in a channel. Copyright 2005 by the American Geophysical Union.

  15. Diurnal variations in optical depth at Mars

    NASA Technical Reports Server (NTRS)

    Colburn, D. S.; Pollack, J. B.; Haberle, R. M.

    1989-01-01

    Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Otpical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combinig these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday.

  16. Modulation Cycles of GCR Diurnal Anisotropy Variation

    NASA Astrophysics Data System (ADS)

    Yi, Y.; Oh, S. Y.

    The diurnal variations of GCR intensity observed by the ground NM stations represent the anisotropic GCR flow at 1 AU. It is generally believed that the variation of the local time of the GCR maximum intensity (phase) has 22-year period of two sunspot cycles. However, there even exists doubt on such anisotropy variation cycle. Those different interpretations come from the lack of enough data since determining the cycle of variation in precision requires data archived over long time of at least two cycles. In order to determine the cycle of GCR anisotropy variation, we carried out the statistical study on the diurnal variation of phase. We examined the 52 years data of Huancayo (Haleakala), 38-year data from Rome, 42-year data from Oulu NM stations. We used new method in determining the yearly mean phase. We applied the F-test to determine the statistically meaningful period of anisotropy phase variation. We found that the coupling coefficients indicating the differences in phase between the NM stations are not constant but dependent on the solar cycle. The phase variation has two components of 22-year and 11-year cycles. The NM station in the high latitude (low cut-off rigidity) shows mainly the 22-year cycle in phase controlled by the diffusion effect with the solar polar magnetic field reversal. However, the lower the latitude of NM station is, the higher contribution from 11-year cycle associated with the solar sunspot cycle. This additional phase variation might be regulated by the drift effect.

  17. Diurnal variations in optical depth at Mars

    NASA Astrophysics Data System (ADS)

    Colburn, D. S.; Pollack, J. B.; Haberle, R. M.

    1989-05-01

    Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Otpical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combinig these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday.

  18. On the diurnal variation of noctilucent clouds

    NASA Technical Reports Server (NTRS)

    Jensen, Eric; Thomas, Gary E.; Toon, Owen B.

    1989-01-01

    The relationship between nuctilucent clouds (NLC), which are observed from the ground usually within 2 or 3 hrs of local midnight, and the polar mesospheric clouds (PMC), which are observed by satellites in full daylight, as well as the reason for the differences in their optical properties and their observed heights are investigated. Based on a suggestion that these differences can be attributed to a diurnal variation in the properties of a single type of cloud, two published models of the diurnal and semidiurnal variations of temperature, vertical wind speed, and eddy diffusion coefficient at high latitude to simulate the evolution of ice clouds over a 24-hr period. The results show that the minimum in temperature at about 2000 hours LT causes a sharp maximum in scattered brightness to occur about 1 hour before local midnight, with up to a factor of 7 variation in cloud brightness between noon and midnight. It is noted, however, that considerable uncertainties exist in these tidal models.

  19. Diurnal timescale feedbacks in the tropical cumulus regime

    NASA Astrophysics Data System (ADS)

    Ruppert, James H.

    2016-09-01

    Although the importance of the diurnal cycle in modulating clouds and precipitation has long been recognized, its impact on the climate system at longer timescales has remained elusive. Mounting evidence indicates that the diurnal cycle may substantially affect leading climate modes through nonlinear rectification. In this study, an idealized cloud-resolving model experiment is executed to isolate a diurnal timescale feedback in the shallow cumulus regime over the tropical warm pool. This feedback is isolated by modifying the period of the diurnal cycle (or removing it), which proportionally scales (or removes) the diurnal thermodynamic forcing that clouds respond to. This diurnal forcing is identified as covarying cycles of static stability and humidity in the lower troposphere, wherein the most unstable conditions coincide with greatest humidity each afternoon. This diurnal forcing yields deeper clouds and greater daily-mean cumulus heating than would otherwise occur, in turn reducing large-scale subsidence from day to day according to the "weak temperature gradient" approximation. This diurnal forcing therefore manifests as a timescale feedback by accelerating the onset of deep convection. The longwave cloud-radiation effect is found to amplify this timescale feedback, since the resulting invigoration of clouds (increased upper-cloud radiative cooling, with suppressed cooling below) scales with cloud depth (i.e., optical thickness), and hence with the magnitude of diurnal forcing. These findings highlight the pressing need to remedy longstanding problems related to the diurnal cycle in many climate models. Given the evident sensitivity of climate variability to diurnal processes, doing so may yield advances in climate prediction at longer timescales.

  20. 40 CFR 86.1233-96 - Diurnal emission test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Evaporative Emission Test Procedures for New Gasoline-Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled Heavy-Duty Vehicles § 86.1233-96 Diurnal emission test. (a)(1) The diurnal emission...

  1. 40 CFR 86.1233-96 - Diurnal emission test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Evaporative Emission Test Procedures for New Gasoline-Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled Heavy-Duty Vehicles § 86.1233-96 Diurnal emission test. (a)(1) The diurnal emission...

  2. 40 CFR 86.1233-96 - Diurnal emission test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Evaporative Emission Test Procedures for New Gasoline-Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled Heavy-Duty Vehicles § 86.1233-96 Diurnal emission test. (a)(1) The diurnal emission...

  3. Diurnal variations from muon data at Takeyama underground station

    NASA Technical Reports Server (NTRS)

    Takahashi, K.; Imai, K.; Imai, T.; Kudo, S.; Wada, M.

    1985-01-01

    An underground station, Takeyama, is introduced, and some results of the solar diurnal and semi-diurnal variations for the period between 1967 and 1984 are presented. There are clear tendencies of double and single solar cycle variations in the daily variations which are in good accord with those detected by other underground and neutron monitor observations.

  4. Children's Diurnal Cortisol Activity during the First Year of School

    ERIC Educational Resources Information Center

    Yang, Pei-Jung; Lamb, Michael E.; Kappler, Gregor; Ahnert, Lieselotte

    2017-01-01

    The present study examined 4- to 5-year-old British children's diurnal cortisol activity during their first year of school. The children's cortisol was measured before enrollment (baseline), upon enrollment, and both 3 and 6 months after enrollment. On each day, cortisol was sampled four times, providing information about the diurnal amount of…

  5. Multitemporal diurnal AVIRIS images of a forested ecosystem

    NASA Technical Reports Server (NTRS)

    Ustin, Susan L.; Smith, Milton O.; Adams, John B.

    1992-01-01

    Both physiological and ecosystem structural information may be derived from diurnal images. Structural information may be inferred from changes in canopy shadows between images and from changes in spectral composition due to changes in proportions of subpixel mixing resulting from the differences in sun/view angles. Physiological processes having diurnal scales also may be measurable if a stable basis for spectral comparison can be established. Six diurnal images of an area east of Mt. Shasta, CA were acquired on 22 Sep. 1989. This unique diurnal data set provided an opportunity to test the consistency of endmember fractions and residuals. It was expected that shade endmember abundances would show the greatest change as lighting geometry changed and less change in the normalized fractional proportion of other endmembers. Diurnal changes in spectral features related to physiological characteristics may be identifiable as changes in wavelength specific residuals.

  6. Diurnal Emotional States Impact the Sleep Course

    PubMed Central

    Delannoy, Julien; Mandai, Osamu; Honoré, Jacques; Kobayashi, Toshinori; Sequeira, Henrique

    2015-01-01

    Background Diurnal emotional experiences seem to affect several characteristics of sleep architecture. However, this influence remains unclear, especially for positive emotions. In addition, electrodermal activity (EDA), a sympathetic robust indicator of emotional arousal, differs depending on the sleep stage. The present research has a double aim: to identify the specific effects of pre-sleep emotional states on the architecture of the subsequent sleep period; to relate such states to the sympathetic activation during the same sleep period. Methods Twelve healthy volunteers (20.1 ± 1.0 yo.) participated in the experiment and each one slept 9 nights at the laboratory, divided into 3 sessions, one per week. Each session was organized over three nights. A reference night, allowing baseline pre-sleep and sleep recordings, preceded an experimental night before which participants watched a negative, neutral, or positive movie. The third and last night was devoted to analyzing the potential recovery or persistence of emotional effects induced before the experimental night. Standard polysomnography and EDA were recorded during all the nights. Results Firstly, we found that experimental pre-sleep emotional induction increased the Rapid Eye Movement (REM) sleep rate following both negative and positive movies. While this increase was spread over the whole night for positive induction, it was limited to the second half of the sleep period for negative induction. Secondly, the valence of the pre-sleep movie also impacted the sympathetic activation during Non-REM stage 3 sleep, which increased after negative induction and decreased after positive induction. Conclusion Pre-sleep controlled emotional states impacted the subsequent REM sleep rate and modulated the sympathetic activity during the sleep period. The outcomes of this study offer interesting perspectives related to the effect of diurnal emotional influences on sleep regulation and open new avenues for potential

  7. Mesosphere Dynamics with Gravity Wave Forcing. 1; Diurnal and Semi-Diurnal Tides

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Chan, K. L.; Porter, H. S.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    We present results from a nonlinear, 3D, time dependent numerical spectral model (NSM), which extends from the ground up into the thermosphere and incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GW). Our focal point is the mesosphere that is dominated by wave interactions. We discuss diurnal and semi-diurnal tides ill the present paper (Part 1) and planetary waves in the companion paper (Part 2). To provide an understanding of the seasonal variations of tides, in particular with regard to gravity wave processes, numerical experiments are performed that lead to the following conclusions: 1. The large semiannual variations in tile diurnal tide (DT), with peak amplitudes observed around equinox, are produced primarily by GW interactions that involve, in part, planetary waves. 2. The DT, like planetary waves, tends to be amplified by GW momentum deposition, which reduces also the vertical wavelength. 3.Variations in eddy viscosity associated with GW interactions tend to peak in late spring and early fall and call also influence the DT. 4. The semidiurnal semidiurnal tide (SDT), and its phase in particular, is strongly influenced by the mean zonal circulation. 5. The SDT, individually, is amplified by GW's. But the DT filters out GW's such that the wave interaction effectively reduces the amplitude of the SDT, effectively producing a strong nonlinear interaction between the DT and SDT. 6.) Planetary waves generated internally by baroclinic instability and GW interaction produce large amplitude modulations of the DT and SDT.

  8. Characterisation and quantification of regional diurnal SST cycles from SEVIRI

    NASA Astrophysics Data System (ADS)

    Karagali, I.; Høyer, J. L.

    2014-04-01

    Hourly SST fields from the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) offer a unique opportunity for the characterisation and quantification of the diurnal cycle of SST in the Atlantic Ocean, the Mediterranean Sea and the Northern European Shelf seas. Six years of SST fields from the SEVIRI dataset are validated against the polar orbiting Advanced Along Track Scanning Radiometer (AATSR) archive to identify biases in the SEVIRI data. Identification of the diurnal signal requires a night-time SST field representative of foundation temperatures, i.e. well-mixed conditions and free of any diurnal signal. Such fields are generated from the SEVIRI archive and are validated against pre-dawn SEVIRI SSTs and night-time SSTs from drifting buoys. The overall SEVIRI-AATSR bias is -0.07 K, and the standard deviation is 0.51 K, based on more than 53 × 106 match-ups. The different methodologies tested for the foundation temperature fields reveal variability introduced by averaging night-time SSTs over many days compared to single-day, pre-dawn values. Diurnal warming is most pronounced in the Mediterranean and Baltic Seas while smallest diurnal signals are found in the Tropics. Longer diurnal warming duration is identified in the high latitudes compared to the Tropics. The mean diurnal signal of monthly mean SST can be up to 0.5° in specific regions.

  9. Diurnal variation of the potassium layer in the upper atmosphere

    PubMed Central

    Feng, W.; Höffner, J.; Marsh, D. R.; Chipperfield, M. P.; Dawkins, E. C. M.; Viehl, T. P.

    2015-01-01

    Abstract Measurements of the diurnal cycle of potassium (K) atoms between 80 and 110 km have been made during October (for the years 2004–2011) using a Doppler lidar at Kühlungsborn, Germany (54.1°N, 11.7°E). A pronounced diurnal variation is observed in the K number density, which is explored by using a detailed description of the neutral and ionized chemistry of K in a three‐dimensional chemistry climate model. The model captures both the amplitude and phase of the diurnal and semidiurnal variability of the layer, although the peak diurnal amplitude around 90 km is overestimated. The model shows that the total potassium density (≈ K + K+ + KHCO3) exhibits little diurnal variation at each altitude, and the diurnal variations are largely driven by photochemical conversion between these reservoir species. In contrast, tidally driven vertical transport has a small effect at this midlatitude location, and diurnal fluctuations in temperature are of little significance because they are small and the chemistry of K is relatively temperature independent. PMID:27478284

  10. Heterogeneity in diurnal variation of tropospheric convection over Indian region

    NASA Astrophysics Data System (ADS)

    Muhammed, Muhsin; Sunilkumar, S. V.

    2016-07-01

    The tropical Tropopause and the features of the Tropical Tropopause Layer (TTL) are governed by troposheric convection from below and radiative heating from above (stratosphere). The brightness temperature in the thermal infrared channel (IRBT) is used as a proxy for identifying tropospheric convection and deep convective clouds. IRBT from Very High Resolution Radiometer (VHRR) onboard KALPANA-1 during different seasons of 2008 to 2014 is being used to examine the heterogeneity of tropospheric convection. Over Indian peninsula, 36 regions have been identified with a spatial resolution of ±0.7° (81 pixels) with equal distance in both longitude and latitude. During monsoon season, a clear diurnal variation in convection is noticed over land when compared with over ocean. Over inland regions, the occurrence of deeper convection occurs during evening and early morning with different diurnal patterns. This can be due to the inhomogeneity of the terrain. It can be noted that the diurnal convection pattern over Arabian Sea is different than Bay of Bengal diurnal convection pattern. Regions near to the western-ghat do not show a clear diurnal variation and shows high occurrence of midlevel clouds (IRBT<265K). During winter (DJF), the occurrence of IRBT below 280K is very less at any time of the day over both land and ocean, which indicates the occurrence of deeper convection is rare. Hence, during winter, the diurnal variations of convection over both land and ocean has insignificant diurnal pattern.

  11. The Diurnal Cycle of Precipitation in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Bowman, K. P.; Fowler, M. D.

    2015-12-01

    Position and intensity data from the International Best Track Archive for Climate Stewardship (IBTrACS) are combined with global, gridded precipitation estimates from the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) for the period 1998 to 2013 to study diurnal variability of precipitation in tropical cyclones. The comprehensive global coverage and large sample size afforded by the two data sets allow robust statistical analysis of storm-averaged diurnal variations and permit stratification of the data in various ways. There is a clearly detectable diurnal variation of precipitation in tropical cyclones with peak rainfall occurring near 0600 local time. For storms of all intensities the amplitude of the diurnal harmonic, which dominates the diurnal cycle, is approximately 7% of the mean rain rate. This corresponds to a peak-to-peak variation of about 15% over the course of the day. The diurnal cycle is similar in all ocean basins. There is evidence that the amplitude of the diurnal cycle increases with increasing storm intensity, but the results are not statistically significant. The results have implications for hurricane forecasting and for our understanding of the processes that regulate oceanic convection.

  12. Diurnal curves of tropospheric ozone in the western United States

    SciTech Connect

    Boehm, M.; McCune, B.; Vandetta, T.

    1991-01-01

    Diurnal curves of tropospheric ozone are characterized for the areas near coniferous forests in the western U.S. A given day of hourly data can be placed into one of 17 classes of diurnal curves simply by knowing the 24-h mean and coefficient of variation or range, or more precisely, by applying equations derived from the authors discriminant analysis. The variation among curves is shown to be related to theory of ozone formation, scavenging, and transport. Season, latitude, and position relative to source areas affect the form of the diurnal curve.

  13. Nonlinear interaction between the diurnal and semidiurnal tides: Terdiurnal and diurnal secondary waves

    NASA Technical Reports Server (NTRS)

    Teitelbaum, H.; Vial, F.; Manson, A. H.; Giraldez, R.; Masseboeuf, M.

    1989-01-01

    Many years of measurements obtained using French meteor radars at Garchy (latitude 47 N) and Montpazier (latitude 44 N) are used to show the existence of an 8 hour oscillation. Some examples of the structure of this wave are displayed and compared with measurements performed at Saskatoon (latitude 52 N) and Budrio (latitude 45 N). This wave can be interpreted as the solar driven terdiurnal tide, or as the result of the nonlinear interaction between the diurnal and semidiurnal tides. Both hypotheses are tested with numerical models. Incidentally, the possible existence of a 24 hour wave resulting from this interaction is also studied.

  14. Biophysical information in asymmetric and symmetric diurnal bidirectional canopy reflectance

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern C.; Caldwell, William F.; Pettigrew, Rita E.; Ustin, Susan L.; Martens, Scott N.; Rousseau, Robert A.; Berger, Kevin M.; Ganapol, B. D.; Kasischke, Eric S.; Clark, Jenny A.

    1991-01-01

    The authors present a theory for partitioning the information content in diurnal bidirectional reflectance measurements in order to detect differences potentially related to biophysical variables. The theory, which divides the canopy reflectance into asymmetric and symmetric functions of solar azimuth angle, attributes asymmetric variation to diurnal changes in the canopy biphysical properties. The symmetric function is attributed to the effects of sunlight interacting with a hypothetical average canopy which would display the average diurnal properties of the actual canopy. The authors analyzed radiometer data collected diurnally in the Thematic Mapper wavelength bands from two walnut canopies that received differing irrigation treatments. The reflectance of the canopies varied with sun and view angles and across seven bands in the visible, near-infrared, and middle infrared wavelength regions. Although one of the canopies was permanently water stressed and the other was stressed in mid-afternoon each day, no water stress signature was unambiguously evident in the reflectance data.

  15. Diurnal blood pressure variation and related behavioral factors.

    PubMed

    Kawano, Yuhei

    2011-03-01

    Blood pressure (BP) varies according to many internal and external factors, and behavioral factors have an important role in diurnal BP variation. BP rises sharply on waking in the morning and falls during sleep at night, although it varies throughout the day and night. These changes in BP are closely related to mental and physical activities, and the sympathetic nervous system mainly contributes to the diurnal variation in BP. Other behavioral factors, such as food consumption and obesity, dietary intake of sodium, drinking and smoking habits, consumption of coffee and tea, and bathing, also affect the diurnal variation in BP. Alterations in diurnal BP variation due to behavioral factors are frequently seen in patients with hypertension and can be classified as morning hypertension, daytime hypertension and nighttime hypertension. Appropriate lifestyle modifications may normalize or improve both the level and rhythm of BP in these patients.

  16. Characterisation and quantification of regional diurnal SST cycles from SEVIRI

    NASA Astrophysics Data System (ADS)

    Karagali, I.; Høyer, J. L.

    2014-09-01

    Hourly SST (sea surface temperature) fields from the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) offer a unique opportunity for the characterisation and quantification of the diurnal cycle of SST in the Atlantic Ocean, the Mediterranean Sea and the northern European shelf seas. Six years of SST fields from SEVIRI are validated against the Advanced Along-Track Scanning Radiometer (AATSR) Reprocessed for Climate (ARC) data set. The overall SEVIRI-AATSR bias is -0.07 K, and the standard deviation is 0.51 K, based on more than 53 × 106 match-ups. Identification of the diurnal signal requires an SST foundation temperature field representative of well-mixed conditions which typically occur at night-time or under moderate and strong winds. Such fields are generated from the SEVIRI archive and are validated against pre-dawn SEVIRI SSTs and night-time SSTs from drifting buoys. The different methodologies tested for the foundation temperature fields reveal variability introduced by averaging night-time SSTs over many days compared to single-day, pre-dawn values. Diurnal warming is most pronounced in the Mediterranean and Baltic seas while weaker diurnal signals are found in the tropics. Longer diurnal warming duration is identified in the high latitudes compared to the tropics. The maximum monthly mean diurnal signal can be up to 0.5 K in specific regions.

  17. Diurnal Variation of Precipitation During MC3E Campaign

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Wu, Di; Matsui, Toshi; Peters-Lidard, Christa; Hou, Arthur; Rienecker, Michele

    2012-01-01

    The diurnal variation of precipitation processes in the United States (US) is well recognized but incompletely understood (Cabone et al. 2002). The diurnal cycle of precipitation has been studied using surface rainfall data, radar reflectivity data, and satellite-derived cloudiness and precipitation (Wallace 1975; Dai et al. 1999; Carbone et al. 2002; Carbone and Tuttle, 2008; Parker and Ahijevych, 2007; Matsui et al. 2010 and others). These observations indicate that the summer-time precipitation most of the North America and typically feature late-afternoon precipitation maxima. These diurnal variation of precipitation can also be generally categorized into three different types: 1) afternoon rainfall maxima due to mesoscale and local circulations over the south and east of the Mississippi and Ohio valleys, 2) nocturnal rainfall maxima from eastward-propagating mesoscale convective systems (MCSs) over the Lee side of Rocky Mountain regions and 3) afternoon rainfall maxima in the Appalachian Mountains, and then propagate eastward toward the coast. The main objective of this paper is to use a regional cloud-scale model with very high-resolution (i.e., WRF) to examine the WRF ability to simulate diurnal variation of precipitation. Specifically, the study will (1) identify the physical processes responsible to diurnal variation of precipitation, (2) examine the sensitivity of resolution (2, 6, 18, and 30 km) to model simulated diurnal variation of precipitation and (3) identify the relationships between microphysics and cumulus parameterization schemes.

  18. On the cumulus diurnal cycle over the tropical warm pool

    NASA Astrophysics Data System (ADS)

    Ruppert, James H.; Johnson, Richard H.

    2016-06-01

    An idealized cloud-resolving model experiment is executed to study the prominent cumulus diurnal cycle in suppressed regimes over the tropical warm pool. These regimes are characterized by daytime cumulus invigoration and cloud-layer moistening connected with enhanced diurnal cycles in shortwave radiative heating (SW) and sea surface temperature (SST). The relative roles of diurnally varying SW and SST in this cumulus diurnal cycle are assessed, wherein radiation is modeled and SST is prescribed. Large-scale subsidence is parameterized using the spectral weak temperature gradient (WTG) scheme, such that large-scale vertical motion (wwtg), and hence subsidence drying, is modulated by diurnal changes in diabatic heating. A control simulation exhibits daytime cumulus invigoration that closely matches observations, including midday cloud-layer moistening. This cumulus invigoration is composed of two distinct modes: (1) a midday nonprecipitating ("forced") mode of predominately shallow clouds, driven by the peak in SST and surface fluxes as the mixed layer deepens and dries; and (2) a precipitating late-afternoon ("active") mode characterized by deeper clouds in connection with a more moist cloud layer. This cloud-layer moistening is driven by the daytime relaxation of wwtg subsidence, which is prompted by the midday peak in SW. The transition from the surface flux-driven forced mode to the active precipitating mode is accompanied by a transition from relatively small-scale boundary layer circulation cells to larger cells that are highly modulated by cold pools, consistent with observations. When the diurnal cycle is removed, clouds are persistently shallower with virtually no rainfall, emphasizing the inherent nonlinearity of the cumulus diurnal cycle.

  19. Antarctic Analog for Diurnal Tidal Motions along Fractures on Enceladus

    NASA Astrophysics Data System (ADS)

    Hurford, T.; Brunt, K. M.; Rhoden, A.

    2013-12-01

    Recent CASSINI VIMS observations have revealed a diurnal variation in the brightness of plume observations from Enceladus. The plume brightness varies by a factor of four as Enceladus orbits Saturn. The plume brightens dramatically as Enceladus approaches its orbital apocenter, and is dimmer near pericenter. The brightness is linked to the amount of material being erupted from the Tiger Stripe fractures in Enceladus' south polar region. The observation of variations in plume brightness (or eruptive output) supports a theoretical model of diurnal tidal stress controlling the location and timing of eruptions from these fractures. Diurnal tidal stress will cyclically place these fractures under tension and compression, which may cause the Tiger Stripes to open and close daily. If conduits to subsurface volatile reservoirs were established while fractures are in tension, the tidally-controlled fault motion would dictate the eruptive output. . This tidal stress model predicts that the Tiger Stripes would experience more tensile stresses near apocenter, thus facilitating more eruptive activity at that time. Tidal stress calculations are based on the tidal flexing expected to occur on Enceladus; surface deformation in response to tidal stresses can only be inferred. The predicted fault motions are small and are not currently observable. However, an Earth analog from the Ross Ice Shelf, Antarctica, may provide insight for the process of induced diurnal tidal motions. Rifts on Antarctic ice shelves are tensile fractures in the floating ice shelf. While the rifts on the Ross Ice Shelf exhibit secular dilation, which causes them to widen with time, data of their motion also show a distinctly diurnal signal. The Ross Ice Shelf experiences tidal forces from both the Moon and Sun, and these forces induce small tidal motions on rifts in the ice shelf. GPS data show small, diurnal tidal motions that dilate and constrict the rift daily. From this analog we conclude that the diurnal

  20. Simulating diurnal variations over the southeastern United States

    NASA Astrophysics Data System (ADS)

    Selman, Christopher; Misra, Vasubandhu

    2015-01-01

    diurnal variations from a high-resolution regional climate model (Regional Spectral Model; RSM) are analyzed from six independent decade long integrations using lateral boundary forcing data from the National Centers for Environmental Prediction Reanalysis 2 (NCEPR2), European Center for Medium-Range Weather Forecasts 40-year Reanalysis and the Twentieth Century Reanalysis (20CR). With each of these lateral boundary forcing data, the RSM is integrated separately using two convection schemes: Relaxed Arakawa-Schubert and Kain-Fritsch. The results show that RSM integrations forced with 20CR have the least fidelity in depicting the seasonal cycle and diurnal variability of precipitation and surface temperature over the Southeastern United States. The remaining four model simulations show comparable skill. The differences in the diurnal amplitude of rainfall during the summer months of the 20CR forced integration from the corresponding NCEPR2 forced integration, for example, is found to be largely from the transient component of the moisture flux convergence. The root mean square error (RMSE) of the seasonal cycle of precipitation and surface temperature of the other four simulations (not forced by 20CR) were comparable to each other and highest in the summer months. But the RMSE of the diurnal amplitude of precipitation and the timing of its diurnal zenith were largest during winter months and least during summer and fall months in the four model simulations (not forced by 20CR). The diurnal amplitude of surface temperature in comparison showed far less fidelity in all models. The phase of the diurnal maximum of surface temperature however showed significantly better validation with corresponding observations in all of the six model simulations.

  1. Annual Climatology of the Diurnal Cycle on the Canadian Prairies

    NASA Astrophysics Data System (ADS)

    Betts, Alan; Tawfik, Ahmed

    2016-01-01

    We show the annual climatology of the diurnal cycle, stratified by opaque cloud, using the full hourly resolution of the Canadian Prairie data. The opaque cloud field itself has distinct cold and warm season diurnal climatologies; with a near-sunrise peak of cloud in the cold season and an early afternoon peak in the warm season. There are two primary climate states on the Canadian Prairies, separated by the freezing point of water, because a reflective surface snow cover acts as a climate switch. Both cold and warm season climatologies can be seen in the transition months of November, March and April with a large difference in mean temperature. In the cold season with snow, the diurnal ranges of temperature and relative humidity increase quasi-linearly with decreasing cloud, and increase from December to March with increased solar forcing. The warm season months, April to September, show a homogeneous coupling to the cloud cover, and a diurnal cycle of temperature and humidity that depends only on net longwave. Our improved representation of the diurnal cycle shows that the warm season coupling between diurnal temperature range and net longwave is weakly quadratic through the origin, rather than the linear coupling shown in earlier papers. We calculate the conceptually important 24-h imbalances of temperature and relative humidity (and other thermodynamic variables) as a function of opaque cloud cover. In the warm season under nearly clear skies, there is a warming of +2oC and a drying of -6% over the 24-h cycle, which is about 12% of their diurnal ranges. We summarize results on conserved variable diagrams and explore the impact of surface windspeed on the diurnal cycle in the cold and warm seasons. In all months, the fall in minimum temperature is reduced with increasing windspeed, which reduces the diurnal temperature range. In July and August, there is an increase of afternoon maximum temperature and humidity at low windspeeds, and a corresponding rise in

  2. Specific Diurnal EMG Activity Pattern Observed in Occlusal Collapse Patients: Relationship between Diurnal Bruxism and Tooth Loss Progression

    PubMed Central

    Kawakami, Shigehisa; Kumazaki, Yohei; Manda, Yosuke; Oki, Kazuhiro; Minagi, Shogo

    2014-01-01

    Aim The role of parafunctional masticatory muscle activity in tooth loss has not been fully clarified. This study aimed to reveal the characteristic activity of masseter muscles in bite collapse patients while awake and asleep. Materials and Methods Six progressive bite collapse patients (PBC group), six age- and gender-matched control subjects (MC group), and six young control subjects (YC group) were enrolled. Electromyograms (EMG) of the masseter muscles were continuously recorded with an ambulatory EMG recorder while patients were awake and asleep. Diurnal and nocturnal parafunctional EMG activity was classified as phasic, tonic, or mixed using an EMG threshold of 20% maximal voluntary clenching. Results Highly extended diurnal phasic activity was observed only in the PBC group. The three groups had significantly different mean diurnal phasic episodes per hour, with 13.29±7.18 per hour in the PBC group, 0.95±0.97 per hour in the MC group, and 0.87±0.98 per hour in the YC group (p<0.01). ROC curve analysis suggested that the number of diurnal phasic episodes might be used to predict bite collapsing tooth loss. Conclusion Extensive bite loss might be related to diurnal masticatory muscle parafunction but not to parafunction during sleep. Clinical Relevance: Scientific rationale for study Although mandibular parafunction has been implicated in stomatognathic system breakdown, a causal relationship has not been established because scientific modalities to evaluate parafunctional activity have been lacking. Principal findings This study used a newly developed EMG recording system that evaluates masseter muscle activity throughout the day. Our results challenge the stereotypical idea of nocturnal bruxism as a strong destructive force. We found that diurnal phasic masticatory muscle activity was most characteristic in patients with progressive bite collapse. Practical implications The incidence of diurnal phasic contractions could be used for the prognostic

  3. Effects of stressor controllability on diurnal physiological rhythms.

    PubMed

    Thompson, Robert S; Christianson, John P; Maslanik, Thomas M; Maier, Steve F; Greenwood, Benjamin N; Fleshner, Monika

    2013-03-15

    Disruptions in circadian and diurnal rhythms are associated with stress-related psychiatric disorders and stressor exposure can disrupt these rhythms. The controllability of the stressor can modulate various behavioral and neurochemical responses to stress. Uncontrollable, but not controllable, stress produces behaviors in rats that resemble symptoms of anxiety and depression. Whether acute stress-induced disruptions in physiological rhythms are sensitive to controllability of the stressor, however, remains unknown. To examine the role of controllability in diurnal rhythm disruption, adult male Sprague-Dawley rats were implanted with Data Sciences International (DSI) biotelemetry devices. Real-time measurements were obtained before, during and after exposure to a controllable or yoked uncontrollable stressor. Controllable and uncontrollable stress equally disrupted diurnal rhythms of locomotor activity and body temperature but not heart rate. The diurnal heart rate the day following stressor exposure was flattened to a greater extent and was significantly higher in rats with control over stress suggesting a relationship between stressor controllability and the heart rate response. Our results are consistent with the conclusion that acute stress-induced disruptions in diurnal physiological rhythms likely contribute little to the behavioral and affective consequences of stress that are sensitive to stressor controllability.

  4. Progress in Research on Diurnal and Semidiurnal Earth Rotation Change

    NASA Astrophysics Data System (ADS)

    Xu, Xueqing

    2015-08-01

    We mainly focus on the progress of research on high frequency changes in the earth rotation. Firstly, we review the development course and main motivating factors of the diurnal and semidiurnal earth rotation change. In recent decades, earth orientation has been monitored with increasing accuracy by advanced space-geodetic techniques, including lunar and satellite laser ranging, very long baseline interferometry and the global positioning system. We are able to obtain the Earth Rotation Parameters (ERP, polar motion and rotation rate changes) by even 1 to 2 hours observation data, form which obvious diurnal and semidiurnal signals can be detected, and compare them with the predicted results by the ocean model. Both the amplitude and phase are in good agreement in the main diurnal and semidiurnal wave frequency, especially for the UT1, whose compliance is 90%, and 60% for polar motion, there are 30% motivating factor of the diurnal and semidiurnal polar motion have not been identified. Then we comprehensively review the different types of global ocean tidal correction models since the last eighties century, as well as the application research on diurnal and semidiurnal polar motion and UT1, the current ocean tidal correction models have 10% to 20% uncertainty, and need for further refinement.

  5. Progress in Research on Diurnal and Semidiurnal Earth Rotation Change

    NASA Astrophysics Data System (ADS)

    Xu, X.; Dong, D.; Zhou, Y.

    2014-12-01

    We mainly focus on the progress of research on high frequency changes in the earth rotation. Firstly, we review the development course and main motivating factors of the diurnal and semidiurnal earth rotation change. In recent decades, earth orientation has been monitored with increasing accuracy by advanced space-geodetic techniques, including lunar and satellite laser ranging, very long baseline interferometry and the global positioning system. We are able to obtain the Earth Rotation Parameters (ERP, polar motion and rotation rate changes) by even 1 to 2 hours observation data, form which obvious diurnal and semidiurnal signals can be detected, and compare them with the predicted results by the ocean model. Both the amplitude and phase are in good agreement in the main diurnal and semidiurnal wave frequency, especially for the UT1, whose compliance is 90%, and 60% for polar motion, there are 30% motivating factor of the diurnal and semidiurnal polar motion have not been identified. Then we comprehensively review the different types of global ocean tidal correction models since the last eighties century, as well as the application research on diurnal and semidiurnal polar motion and UT1, the current ocean tidal correction models have 10% to 20% uncertainty, and need for further refinement.

  6. Patterns of Diurnal Marine Stratocumulus Cloud Fraction Variability

    SciTech Connect

    Burleyson, Casey D.; Yuter, S. E.

    2015-04-01

    The spatial patterns of subtropical marine stratocumulus cloud fraction variability on diurnal time scales are examined using high temporal resolution cloud masks based on 30-min 4 km x 4 km geosynchronous IR data for the period 2003-2010. This data set permits comparison of low cloud fraction variability characteristics among the three marine stratocumulus regions in the southeast Pacific, southeast Atlantic and northeast Pacific. In all three regions, the largest diurnal cycles and earliest time of cloud break up occur on the edges of the cloud field where cloud fractions are in general lower. During the peak season of cloudiness in the southeast Pacific and southeast Atlantic the amplitude of the diurnal cycle on the edges of the cloud deck was greater than 40%, more than double the value found in the center of each cloud deck. The rate at which the cloud breaks up during the day is closely tied to starting cloud fraction at dawn and the shortwave radiative flux. The maximum rate of cloud breakup occurs near 1200 LT. Cloud fraction begins to increase at 1600 LT (before the sun sets) and reaches its maximum value just before dawn. The diurnal cycle characteristics of the southeast Pacific and southeast Atlantic marine stratocumulus cloud decks are more similar to each other than to those in the northeast Pacific. The northeast Pacific cloud deck has weaker diurnal variation, slower rates of cloud breakup during the day for a given cloud fraction at dawn, and higher probabilities for cloud break up overnight.

  7. Diurnal variation of outgoing longwave radiation in the tropics

    NASA Technical Reports Server (NTRS)

    Hartmann, D. L.; Recker, E. E.

    1986-01-01

    The diurnal harmonic in longwave emission in the tropical belt (30 deg N-30 deg S) is estimated from nine years of NOAA polar-orbiting satellite data. The results are compared successfully with Nimbus-7 ERB scanner data and with GOES-West geosynchronous satellite data. An interesting and consistent diurnal variation in longwave emission is found over the regions of intense oceanic convection, such as the ITCZ and SPCZ regions, with a peak-to-peak variation of 6-8 W/sq m and a maximum in the morning (0600-1200 LST). Histogram analysis indicates that this variation is associated with a diurnal variation in convective cloud (about 400 mb). Over regions of very intense convection, a diurnal variation of very high clouds (above 100 mb), which is out of phase with the variations at lower levels in the atmosphere, reduces the magnitude of the diurnal harmonic in longwave emission. It is interesting that histograms based on data averaged over 8-km and 250-km boxes give the same qualitative information about cloud and emission variability.

  8. Does the Neuroprotective Role of Anandamide Display Diurnal Variations?

    PubMed Central

    Martinez-Vargas, Marina; Morales-Gomez, Julio; Gonzalez-Rivera, Ruben; Hernandez-Enriquez, Carla; Perez-Arredondo, Adan; Estrada-Rojo, Francisco; Navarro, Luz

    2013-01-01

    The endocannabinoid system is a component of the neuroprotective mechanisms that an organism displays after traumatic brain injury (TBI). A diurnal variation in several components of this system has been reported. This variation may influence the recovery and survival rate after TBI. We have previously reported that the recovery and survival rate of rats is higher if TBI occurs at 1:00 than at 13:00. This could be explained by a diurnal variation of the endocannabinoid system. Here, we describe the effects of anandamide administration in rats prior to the induction of TBI at two different times of the day: 1:00 and 13:00. We found that anandamide reduced the neurological damage at both times. Nevertheless, its effects on bleeding, survival, food intake, and body weight were dependent on the time of TBI. In addition, we analyzed the diurnal variation of the expression of the cannabinoid receptors CB1R and CB2R in the cerebral cortex of both control rats and rats subjected to TBI. We found that CB1R protein was expressed more during the day, whereas its mRNA level was higher during the night. We did not find a diurnal variation for the CB2R. In addition, we also found that TBI increased CB1R and CB2R in the contralateral hemisphere and disrupted the CB1R diurnal cycle. PMID:24287910

  9. Diurnal variation of overdense meteor echo duration and ozone

    NASA Technical Reports Server (NTRS)

    Simek, Milos

    1992-01-01

    The diurnal variation of the median duration of overdense sporadic radar meteor echoes is examined. The meteors recorded in August, December, and January by the Ondrejov meteor radar during the period 1958-1990 were used for the analysis. A maximum median echo duration 1-3 hours after the time of local sunrise in the meteor region confirms the already known sunrise effect. Minimum echo duration occurring at the time of sunset seems to be the most important point of diurnal variation of the echo duration, when ozone is no longer dissociated by solar UV radiation. The effect of diurnal changes of the echo duration should be considered when the mass distribution of meteor showers is analyzed.

  10. Epigenetic mechanisms in diurnal cycles of metabolism and neurodevelopment

    PubMed Central

    Powell, Weston T.; LaSalle, Janine M.

    2015-01-01

    The circadian cycle is a genetically encoded clock that drives cellular rhythms of transcription, translation and metabolism. The circadian clock interacts with the diurnal environment that also drives transcription and metabolism during light/dark, sleep/wake, hot/cold and feast/fast daily and seasonal cycles. Epigenetic regulation provides a mechanism for cells to integrate genetic programs with environmental signals in order produce an adaptive and consistent output. Recent studies have revealed that DNA methylation is one epigenetic mechanism that entrains the circadian clock to a diurnal environment. We also review recent circadian findings in the epigenetic neurodevelopmental disorders Prader–Willi, Angelman and Rett syndromes and hypothesize a link between optimal brain development and intact synchrony between circadian and diurnal rhythms. PMID:26105183

  11. Diurnal variations in water vapor over Central and South America

    NASA Astrophysics Data System (ADS)

    Meza, Amalia; Mendoza, Luciano; Bianchi, Clara

    2016-07-01

    Diurnal variations in atmospheric integrated water vapor (IWV) are studied employing IWV estimates, with a 30 minutes sampling rate, derived from Global Navigation Satellite Systems (GNSS) observations during the period 2007-2013. The analysis was performed in 73 GNSS tracking sites (GPS + GLONASS) which have more than 5 years of data. The selected area involves different climate types, from polar to tropical, with different diurnal variations of the integrated total humidity content. There are many processes that could induce diurnal variations in atmospheric water vapor (Dai et al, 1999 a,b), the most relevant causes are: surface evapotranspiration, atmospheric large-scale vertical motion, atmospheric low-level moisture convergence and precipitation and vertical mixing (which affects the vertical distribution of water vapor but does not affect the IWV). The numerical tools, Singular Value Decomposition and classical Multidimensional Scaling methods, are used to study these variations, considering the measurements made at each stations, as sample in the analysis. The aim of this investigation is to identify the IWV variability with respect to the local time associated to the different climate regions. In order to improve our analysis, all available weather information, such as radiosondes measurements (which are few), measurements of pressure and temperature and Numerical Weather Models reanalysis data, are used. Reference: Dai, A., K. E. Trenberth, and T. R. Karl, 1999 a: Effects of clouds, soil moisture, precipitation and water vapor on diurnal temperature range. J. Climate, 12, 2451-2473. Dai, A., F. Giorgi, and K. E. Trenberth, 1999 b: Observed and model simulated precipitation diurnal cycle over the contiguous United States.J. Geophys. Res., 104, 6377-6402. KEYWORDS: water vapor, diurnal cycle, GNSS

  12. Numerical Experiments of the Diurnal Cycle of Axisymmetric Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Navarro, E. L.; Hakim, G. J.

    2015-12-01

    Recent observational and modeling studies have shown that the diurnal cycle of radiation may be fundamentally linked to structural changes in the lifetime of a tropical cyclone. While these studies suggest that an underlying mechanism within the storm may exist, the dynamics for this response are still largely unexplained. Previous modeling studies were limited due to model configuration (e.g., initial and boundary conditions) as well as to radiative parameterization schemes. In this presentation, two new investigations are discussed to reexamine the role of the daily cycle of radiation on axisymmetric hurricane structure. In the first study, a tropical cyclone lasting 324 days is generated in Cloud Model 1 (CM1, see Bryan and Rotunno 2009) to quantify a tropical cyclone diurnal signal. A coherent response is observed in the temperature, wind, and cloud ice fields that accounts for up to a third of the overall variance. Composite analysis of each hour of the day shows a diurnal cycle in the storm intensity that, relative to the mean, intensifies in the early hours of the morning and is consistent with observational studies. Examination of the radial and vertical wind suggests two distinct circulations forced by the diurnal cycle: (1) a radiatively-driven circulation in the outflow layer due to absorption of solar radiation, and (2) a convectively-driven circulation within the storm due to latent heating. These responses are coupled and are periodic with respect to the diurnal cycle. In the second study, following the method of Pendergrass and Willoughby (2009) and Willoughby (2009), hypothesis tests using various prescribed, periodic heating distributions are performed to examine the dynamical response of the storm to radiation. Results reveal significant changes to the secondary-circulation structure of the storm, as well as to the intensification of the primary vortex. Sensitivity to the chosen heating distribution as well as to the initial vortex are discussed

  13. Nonmigrating diurnal tides in the equatorial middle atmosphere

    SciTech Connect

    Lieberman, R.S.

    1992-01-01

    Data from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) are used to analyze the diurnal tides in the middle atmosphere. A novel aspect of this study is the emphasis on the relative importance of the nonmigrating components. These modes display a high degree of temporal variability during the LIMS observing period, and contribute substantially to the diurnal signal in wind and temperature. Their observed vertical phase variations are variable; however there is evidence for upward energy propagation. It has long been hypothesized that nonmigrating tides are driven by the diurnally-varying zonally asymmetric tropospheric heating constituents. This premise is examined by employing a linear tidal model to simulate the response of the atmosphere to realistic tidal drives. These quantities are calculated from the NCAR Community Climate Model. The large-scale CCM2 diurnal surface pressure, OLR and hydrology are well simulated under July and January conditions. The CCM2 diurnal fields of short-wave radiative, convective and diffusive PBL heating are used as input to a linear tidal model with Newtonian cooling. This model successfully reproduces many observed features of the migrating and nonmigrating diurnal surface pressure tides at low latitudes. In the middle atmosphere, tropospheric solar heating is the dominant source of the migrating tide. The zonal means and eastward migrating wavenumber one components are also associated with radiative heating. The eastward migrating wavenumber three pattern is strongly linked to the dry and moist convective heating as well. The observed eastward migrating tides are harder to simulate, due in part to the failure of the linear model to incorporate the dissipative effects to which they are prone.

  14. Diurnal changes in ocean color in coastal waters

    NASA Astrophysics Data System (ADS)

    Arnone, Robert; Vandermeulen, Ryan; Ladner, Sherwin; Ondrusek, Michael; Kovach, Charles; Yang, Haoping; Salisbury, Joseph

    2016-05-01

    Coastal processes can change on hourly time scales in response to tides, winds and biological activity, which can influence the color of surface waters. These temporal and spatial ocean color changes require satellite validation for applications using bio-optical products to delineate diurnal processes. The diurnal color change and capability for satellite ocean color response were determined with in situ and satellite observations. Hourly variations in satellite ocean color are dependent on several properties which include: a) sensor characterization b) advection of water masses and c) diurnal response of biological and optical water properties. The in situ diurnal changes in ocean color in a dynamic turbid coastal region in the northern Gulf of Mexico were characterized using above water spectral radiometry from an AErosol RObotic NETwork (AERONET -WavCIS CSI-06) site that provides up to 8-10 observations per day (in 15-30 minute increments). These in situ diurnal changes were used to validate and quantify natural bio-optical fluctuations in satellite ocean color measurements. Satellite capability to detect changes in ocean color was characterized by using overlapping afternoon orbits of the VIIRS-NPP ocean color sensor within 100 minutes. Results show the capability of multiple satellite observations to monitor hourly color changes in dynamic coastal regions that are impacted by tides, re-suspension, and river plume dispersion. Hourly changes in satellite ocean color were validated with in situ observation on multiple occurrences during different times of the afternoon. Also, the spatial variability of VIIRS diurnal changes shows the occurrence and displacement of phytoplankton blooms and decay during the afternoon period. Results suggest that determining the temporal and spatial changes in a color / phytoplankton bloom from the morning to afternoon time period will require additional satellite coverage periods in the coastal zone.

  15. Comparative Analysis of Vertebrate Diurnal/Circadian Transcriptomes

    PubMed Central

    Boyle, Greg; Richter, Kerstin; Priest, Henry D.; Traver, David; Mockler, Todd C.; Chang, Jeffrey T.; Kay, Steve A.

    2017-01-01

    From photosynthetic bacteria to mammals, the circadian clock evolved to track diurnal rhythms and enable organisms to anticipate daily recurring changes such as temperature and light. It orchestrates a broad spectrum of physiology such as the sleep/wake and eating/fasting cycles. While we have made tremendous advances in our understanding of the molecular details of the circadian clock mechanism and how it is synchronized with the environment, we still have rudimentary knowledge regarding its connection to help regulate diurnal physiology. One potential reason is the sheer size of the output network. Diurnal/circadian transcriptomic studies are reporting that around 10% of the expressed genome is rhythmically controlled. Zebrafish is an important model system for the study of the core circadian mechanism in vertebrate. As Zebrafish share more than 70% of its genes with human, it could also be an additional model in addition to rodent for exploring the diurnal/circadian output with potential for translational relevance. Here we performed comparative diurnal/circadian transcriptome analysis with established mouse liver and other tissue datasets. First, by combining liver tissue sampling in a 48h time series, transcription profiling using oligonucleotide arrays and bioinformatics analysis, we profiled rhythmic transcripts and identified 2609 rhythmic genes. The comparative analysis revealed interesting features of the output network regarding number of rhythmic genes, proportion of tissue specific genes and the extent of transcription factor family expression. Undoubtedly, the Zebrafish model system will help identify new vertebrate outputs and their regulators and provides leads for further characterization of the diurnal cis-regulatory network. PMID:28076377

  16. Trial of Oral Metoclopramide on Diurnal Bruxism of Brain Injury

    PubMed Central

    Yi, Ho Sung; Seo, Mi Ri

    2013-01-01

    Bruxism is a diurnal or nocturnal parafunctional activity that includes tooth clenching, bracing, gnashing, and grinding. The dopaminergic system seems to be the key pathophysiology of bruxism and diminution of dopaminergic transmission at the prefrontal cortex seems to induce it. We report two patients with diurnal bruxism in whom a bilateral frontal lobe injury resulted from hemorrhagic stroke or traumatic brain injury. These patients' bruxism was refractory to bromocriptine but responded to low-dose metoclopramide therapy. We propose that administering low doses of metoclopramide is possibly a sound method for treating bruxism in a brain injury patient with frontal lobe hypoperfusion on positron emission tomography imaging. PMID:24466522

  17. Diurnality, nocturnality, and the evolution of primate visual systems.

    PubMed

    Ankel-Simons, F; Rasmussen, D T

    2008-01-01

    Much of the recent research on the evolution of primate visual systems has assumed that a minimum number of shifts have occurred in circadian activity patterns over the course of primate evolution. The evolutionary origins of key higher taxonomic groups have been interpreted by some researchers as a consequence of a rare shift from nocturnality to diurnality (e.g., Anthropoidea) or from diurnality to nocturnality (e.g., Tarsiidae). Interpreting the evolution of primate visual systems with an ecological approach without parsimony constraints suggests that the evolutionary transitions in activity pattern are more common than what would be allowed by parsimony models, and that such transitions are probably less important in the origin of higher level taxa. The analysis of 17 communities of primates distributed widely around the world and through geological time shows that primate communities consistently contain both nocturnal and diurnal forms, regardless of the taxonomic sources of the communities. This suggests that primates in a community will adapt their circadian pattern to fill empty diurnal or nocturnal niches. Several evolutionary transitions from one pattern to the other within narrow taxonomic groups are solidly documented, and these cases probably represent a small fraction of such transitions throughout the Cenozoic. One or more switches have been documented among platyrrhine monkeys, Malagasy prosimians, Eocene omomyids, Eocene adapoids, and early African anthropoids, with inconclusive but suggestive data within tarsiids. The interpretation of living and extinct primates as fitting into one of two diarhythmic categories is itself problematic, because many extant primates show significant behavioral activity both nocturnally and diurnally. Parsimony models routinely interpret ancestral primates to have been nocturnal, but analyses of morphological and genetic data indicate that they may have been diurnal, or that early primate radiations were likely to

  18. Diurnal regulation of plastid genes in Populus deltoides.

    PubMed

    Reddy, M S; Naithani, S; Tuli, R; Sane, P V

    2000-12-01

    Light regulates leaf and chloroplast development, together with overall chloroplast gene expression at various levels. Plants respond to diurnal and seasonal changes in light by changing expression of photosynthesis genes and metabolism. In Populus deltoides, a deciduous tree species, leaf development begins in the month of March and leaf maturation is attained by summer, which is subsequently followed by autumnal senescence and fall. In the present study, diurnal changes in the steady state transcript levels of plastid genes were examined in the fully developed leaves during summer season. Our results show that steady state level of the psaA/B, psbA, psbEFLJ and petA transcripts showed differential accumulation during diurnal cycle in summer. However, there was no significant change in the pigment composition during the day/night cycle. Our studies suggest that the diurnal regulation of steady state mRNA accumulation may play a crucial role during daily adjustments in plants life with rapidly changing light irradiance and temperature.

  19. Diurnal water relations of walnut trees - Implications for remote sensing

    NASA Technical Reports Server (NTRS)

    Weber, James A.; Ustin, Susan L.

    1991-01-01

    Leaflet water content (WC), relative water content (RWC), and water potential, Phi(lf) were measured as indicators of diurnal change in tree water status in an experimental walnut orchard receiving two irrigation treatments: 100 and 33 percent of potential evapotranspiration (PET). Diurnal change was greatest in Phi(lf) throughout the experimental period, with minima occurring each day in early to mid-afternoon and maxima between midnight and sunrise. Leaflet WC and RWC were lower in the afternoon than at night, but had greater variability so that the diurnal pattern was not as clear. Comparison between the pattern of Phi(lf) and dielectric constants (DCs) measured from probes inserted 2 cm into a tree hole showed that both declined nearly in parallel in the morning. Phi(lf) recovered more rapidly than DC in the afternoon. This temporal discrepancy could be caused by cavitation of xylem elements in the vicinity of the DC probe. Microwave backscatter for L- and X-bands also measured diurnal variation that had local minima in the afternoon, but the pattern among wavelength and polarization signatures was complex.

  20. Diurnal Variability and Kelvin Wave Propagation Through Maritime Continent

    NASA Astrophysics Data System (ADS)

    Flatau, M. K.; Baranowski, D. B.; Flatau, P. J.; Matthews, A. J.

    2014-12-01

    The 10 year series of the equatorial Kelvin waves obtained from the analysis of TRMM precipitation were examined to evaluate the impact of the diurnal variability of convection on the wave propagation through Maritime Continent. The convection in the Kelvin waves appears to be strongly phase locked in the area of the Maritime continent with the pronounced afternoon maximum. The diurnal phase locking is also evident as Kelvin waves propagate trough the Indian Ocean basin, suggesting that at least some Kelvin waves in this area are forced by the diurnally varying heat source related either to the convection over the land such as Eastern Africa or Madagascar, or over ocean areas with the high SST variability. We examine the hypothesis that the "matching" of the convective phase of the waves with the afternoon maximum of convection over Sumatra influences the wave strength after it crosses the Maritime Continent and can contribute to MJO propagation. The observational results based on observed Kelvin waves are supported by the results of the shallow water model of the interaction of the dry Kelvin wave with the diurnally oscillating heat source.

  1. Successful Use of the Nocturnal Urine Alarm for Diurnal Enuresis.

    ERIC Educational Resources Information Center

    Friman, Patrick C.; Vollmer, Dennis

    1995-01-01

    A urine alarm, typically used to treat nocturnal enuresis, was effectively used to treat diurnal enuresis in a 15-year-old female with depression, attention deficit hyperactivity disorder, and conduct disorder. The study indicated that the alarm eliminated wetting in both treatment phases and that continence was maintained at three-month and…

  2. Diurnal Patterns of Blowing Dust on the Llano Estacado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a Tapered Element Oscillating Microbalance (TEOM), hourly dust data was collected in Lubbock, Texas, from January 1, 2003, to January 1, 2008. Diurnal patterns of dust concentration were computed by averaging hourly values associated with a given “time of day” for all days within the 5-yr sa...

  3. Diurnal variation of galactic cosmic ray intensity on quiet days

    NASA Technical Reports Server (NTRS)

    Kumar, S.; Datt, S. C.

    1985-01-01

    A detailed study of the diurnal variation on long term basis was performed on geomagnetically quiet days using the experimental data of the cosmic ray intensity from the worldwide neutron monitoring stations. During the period when the polarity of the solar magnetic field in the Northern Hemisphere of the sun is negative the phase and amplitude of the diurnal anisotropy on quiet days was observed to remain almost constant. When the polarity of solar magnetic field in the Northern Hemisphere changes from negative to positive, a shift in the phase of the diurnal anisotropy on quiet days towards earlier hours is observed and the shift is found to be maximum during minimum solar activity periods 1953-54 and 1975-76. When the polarity of solar magnetic field changes from positive to negative in the Northern Hemisphere of the Sun the phase of the diurnal anisotropy on quiet days recovers to its usual direction of corotational anisotropy and is observed to remain almost constant till the polarity of the solar magnetic field does not change.

  4. Diurnal variation of tropospheric relative humidity in tropical regions

    NASA Astrophysics Data System (ADS)

    Moradi, Isaac; Arkin, Philip; Ferraro, Ralph; Eriksson, Patrick; Fetzer, Eric

    2016-06-01

    Despite the importance of water vapor especially in the tropical region, the diurnal variations of water vapor have not been completely investigated in the past due to the lack of adequate observations. Measurements from Sondeur Atmosphérique du Profil d'Humidité Intertropicale par Radiométrie (SAPHIR) onboard the low inclination Megha-Tropiques satellite with frequent daily revisits provide a valuable dataset for investigating the diurnal and spatial variation of tropospheric relative humidity in the tropical region. In this study, we first transformed SAPHIR observations into layer-averaged relative humidity, then partitioned the data based on local observation time into 24 bins with a grid resolution of one degree. Afterwards, we fitted Fourier series to the binned data. Finally, the mean, amplitude, and diurnal peak time of relative humidity in tropical regions were calculated for each grid point using either the measurements or Fourier series. The results were separately investigated for different SAPHIR channels as well as for relative humidity with respect to both liquid and ice phases. The results showed that the wet and dry regions are, respectively, associated with convective and subsidence regions which is consistent with the previous studies. The mean tropospheric humidity values reported in this study are generally 10 to 15 % higher than those reported using infrared observations which is because of strict cloud screening for infrared measurements. The results showed a large inhomogeneity in diurnal variation of tropospheric relative humidity in tropical region. The diurnal amplitude was larger over land than over ocean and the oceanic amplitude was larger over convective regions than over subsidence regions. The results showed that the diurnal amplitude is less than 10 % in middle and upper troposphere, but it is up to 30 % in lower troposphere over land. Although the peak of RH generally occurs over night or in early morning, there are several

  5. Low cost electronic ultracapacitor interface technique to provide load leveling of a battery for pulsed load or motor traction drive applications

    DOEpatents

    King, Robert Dean; DeDoncker, Rik Wivina Anna Adelson

    1998-01-01

    A battery load leveling arrangement for an electrically powered system in which battery loading is subject to intermittent high current loading utilizes a passive energy storage device and a diode connected in series with the storage device to conduct current from the storage device to the load when current demand forces a drop in battery voltage. A current limiting circuit is connected in parallel with the diode for recharging the passive energy storage device. The current limiting circuit functions to limit the average magnitude of recharge current supplied to the storage device. Various forms of current limiting circuits are disclosed, including a PTC resistor coupled in parallel with a fixed resistor. The current limit circuit may also include an SCR for switching regenerative braking current to the device when the system is connected to power an electric motor.

  6. Diurnal cycle of convection during the CAIPEEX 2011 experiment

    NASA Astrophysics Data System (ADS)

    Resmi, EA; Malap, Neelam; Kulkarni, Gayatri; Murugavel, P.; Nair, Sathy; Burger, Roelof; Prabha, Thara V.

    2016-10-01

    The diurnal cycle of convective storm events is investigated in the study with the help of C-band radar reflectivity data during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX 2011) in combination with other ground-based observations. A threshold reflectivity of 25 dBZ is used to identify the initiation of storms. Observations from collocated sensors such as a microwave radiometer profiler, water vapor measurement from eddy covariance system, and wind lidar measurements are used to investigate the characteristic features and diurnal cycle of convectively initiated storms from 21st September to 5th November 2011. The maximum reflectivity follows a normal distribution with a mean value of 40 dBZ. The cloud depth over the domain varied between 5 and 15 km corresponding to a range of reflectivity of 30-50 dBZ values. In the diurnal cycle, double maximum in the precipitation flux is noted—one during the afternoon hours associated with the diurnal heating and the other in the nocturnal periods. The nocturnal precipitation maximum is attributed to initiation of several single-cell storms (of congestus type) with a duration that is larger than the storms initiated during the daytime. The convective available potential energy (CAPE) showed a diurnal variation and was directly linked with the surface level water vapor content. The high CAPE favored single storms with a reflectivity >40 dBZ and higher echo top heights. In the evening or late night hours, a nocturnal low-level jet present over the location together with the reduced stability above the cloud base favored enhancement of low-level moisture, CAPE, and further initiation of new convection. The study illustrated how collocated observations could be used to study storm initiation and associated thermodynamic features.

  7. Work stress models and diurnal cortisol variations: The SALVEO study.

    PubMed

    Marchand, Alain; Juster, Robert-Paul; Durand, Pierre; Lupien, Sonia J

    2016-04-01

    The objective of this study was to assess components, subscales, and interactions proposed by the popular Job Demand-Control (JDC), Job Demand-Control-Support (JDCS), and Effort-Reward Imbalance (ERI) work stress models in relation to diurnal variation of the stress hormone cortisol. Participants included 401 day-shift workers employed from a random sampling of 34 Canadian workplaces. Questionnaires included the Job Content Questionnaire to measure psychological demands, decision latitude, and social support as well as the Effort-Reward Imbalance Questionnaire to measure effort, reward, and overcommitment. Salivary cortisol was collected on 2 working days at awaking, +30 min after awaking, 1400h, 1600h, and bedtime. Multilevel regressions with 3 levels (time of day, workers, workplaces) were performed. Results revealed that JDC, JDCS and ERI interactions were not statistically associated with variations in diurnal cortisol concentrations. By contrast when assessing specific work stress subscales, increased psychological demands were linked to decreased bedtime cortisol, increased job recognition was linked to increased cortisol +30 min after waking and at bedtime, and finally increased overcommitment was linked to increased awakening cortisol and decreased cortisol at 1400h, 1600h, and bedtime. Sex moderation effects principally among men were additionally detected for psychological demands, total social support, and supervisor support. Our findings suggest that components and subsubscales of these popular work stress models rather than theorized interactions are more meaningful in explaining diurnal cortisol variations. In particular, psychological demands, job recognition, overcommitment, and to a lesser extent social support at work are the most significant predictors of diurnal cortisol variation in this large sample of Canadian workers. Importantly, the overall effect sizes of these subscales that explained diurnal cortisol concentrations were weak.

  8. Diurnality of soil nitrous oxide (N2O) emissions

    NASA Astrophysics Data System (ADS)

    Gelfand, I.; Moyer, R.; Poe, A.; Pan, D.; Abraha, M.; Chen, J.; Zondlo, M. A.; Robertson, P.

    2015-12-01

    Soil emissions of nitrous oxide (N2O) are important contributors to the greenhouse gas balance of the atmosphere. Agricultural soils contribute ~65% of anthropogenic N2O emissions. Understanding temporal and spatial variability of N2O emissions from agricultural soils is vital for closure of the global N2O budget and the development of mitigation opportunities. Recent studies have observed higher N2O fluxes during the day and lower at night. Understanding the mechanisms of such diurnality may have important consequences for our understanding of the N cycle. We tested the hypothesis that diurnal cycles are driven by root carbon exudes that stimulate denitrification and therefore N2O production. Alternatively, we considered that the cycle could result from higher afternoon temperatures that accelerate soil microbial activity. We removed all plants from a corn field plot and left another plot untouched. We measured soil N2O emissions in each plot using a standard static chamber technique throughout the corn growing season. And also compared static chamber results to ecosystem level N2O emissions as measured by eddy covariance tower equipped with an open-path N2O sensor. We also measured soil and air temperatures and soil water and inorganic N contents. Soil N2O emissions followed soil inorganic N concentrations and in control plot chambers ranged from 10 μg N m-2 hr-1 before fertilization to 13×103 after fertilization. We found strong diurnal cycles measured by both techniques with emissions low during night and morning hours and high during the afternoon. Corn removal had no effect on diurnality, but had a strong effect on the magnitude of soil N2O emissions. Soil temperature exhibited a weak correlation with soil N2O emissions and could not explain diurnal patterns. Further studies are underway to explore additional mechanisms that might contribute to this potentially important phenomena.

  9. DIURNAL CYCLE OF PRECIPITABLE WATER VAPOR OVER SPAIN

    SciTech Connect

    Ortiz de Galisteo, J. P.; Cachorro, V. E.; Toledano, C.; Torres, B.; Laulainen, Nels S.; Bennouna, Yasmine; de Frutos, A. M.

    2011-05-20

    Despite the importance of the diurnal cycle of precipitable water vapor (PWV), its knowledge is very limited due to the lack of data with sufficient temporal resolution. Currently, from GPS receivers, PWV can be obtained with high temporal resolution in all weather conditions for all hours of the day. In this study we have calculated the diurnal cycle of PWV for ten GPS stations over Spain. The minimum value is reached approximately at the same time at all the stations, ~0400-0500 UTC, whereas the maximum is reached in the second half of the day, but with a larger dispersion of its occurrence between stations. The amplitude of the cycle ranges between 0.72 mm and 1.78 mm. The highest values are recorded at the stations on the Mediterranean coast, with a doubling of the values of the stations on the Atlantic coast or inland. The amplitude of the PWV cycle, relative to the annual mean value, ranges between 8.8 % on the Mediterranean coast and 3.6 % on the Atlantic coast. Two distinctly different seasonal diurnal cycles have been identified, one in winter and other in summer, with spring and autumn being only transition states. The winter cycle is quite similar at all locations, whereas in summer, local effects are felt strongly, making the diurnal cycle quite different between stations. The amplitude of the summer cycle is 1.69 mm, it is almost double the winter one (0.93 mm). Analogous to the annual cycles, the seasonal cycles of the different stations are more similar during the night and early morning hours than during the afternoon. The observed features of the PWV diurnal cycle are explained in a qualitative way on the basis of the air temperature, the transport of moisture by local winds, and the turbulent vertical mixing.

  10. Observations of SST diurnal variability in the South China Sea

    NASA Astrophysics Data System (ADS)

    Tu, Qianguang; Pan, Delu; Hao, Zengzhou; Chen, Jianyu

    2015-10-01

    In this study, a 3-hourly time resolution gap free sea surface temperature (SST) analysis is generated to resolve the diurnal cycle in the South China Sea (SCS, 0°-25°N, 100°-125°E).It takes advantage of hourly geostationary satellite MTSAT observations and combines three infrared and two microwave polar satellite observations at different local times. First, all the data are classified into eight SST datasets at 3 hour intervals and then remapped to 0.05°resolution grids. A series of critical quality control is done to remove the outliers.Then bias adjustment is applied to the polar satellite observations with reference to the MTSAT data. Finally, the six satellites SST data are blended by using the optimal interpolated algorithm. The 3-hourly blended SST is compared against buoy measurements. It shows a good agreement that the biases do not exceed 0.2 °C and root mean square errors range from 0.5 to 0.65 °C. A typical diurnal cycle similar to sine wave is observed. The minimum SST occurs at around 0600h and warming peak occurring between 1300h and 1500h local solar time and then decrease in the late afternoon, tapering off at night on March 13, 2008 for example. The frequency of diurnal warming events derived from four years of the blended SST provides solid statistics to investigate the seasonal and spatial distributions of the diurnal warming in the SCS. The sea surface diurnal warming tends to appear more easily in spring, especially in the coastal regions than other seasons and the central regions.

  11. Aging diurnal rhythms and chronic stress: Distinct alteration of diurnal rhythmicity of salivary alpha-amylase and cortisol.

    PubMed

    Strahler, Jana; Berndt, Christiane; Kirschbaum, Clemens; Rohleder, Nicolas

    2010-05-01

    The present study assessed diurnal profiles of salivary alpha-amylase (sAA), proposed as a marker of autonomic activity, and salivary cortisol in competitive ballroom dancers as well as age- and sex-matched controls to investigate age-related changes of basal activity and potential chronic psychosocial stress-related alterations. According to the Allostatic Load (AL) hypothesis of a cumulative wear and tear of the body we expected to see physiological accumulation of the effects of stress and age especially pronounced in older dancers. Dancers and controls collected five saliva samples throughout the day. Daily overall output of sAA was elevated in older adults while there was no effect of age on mean cortisol levels. Alterations of diurnal rhythms were only seen in younger male dancers showing a flattened diurnal profile of sAA and younger dancers and female older dancers showing a blunted diurnal rhythmicity of cortisol. Furthermore, we found a negative correlation between summary indices of basal sAA and the amount of physical activity. In conclusion, higher overall output of sAA in older adults is in line with the phenomenon of a sympathetic "drive" with increasing age. Furthermore, a lower output of sAA in people who are more physical active is in line with the hypothesis of an exercise-induced decrease of sympathetic activity. Overall, our study does not support the AL hypothesis, but rather highlights the importance of regular physical activity and social environment in promoting health.

  12. Do Diurnal Aerosol Changes Affect Daily Average Radiative Forcing?

    SciTech Connect

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

    2013-06-17

    Strong diurnal variability of aerosol has been observed frequently for many urban/industrial regions. How this variability may alter the direct aerosol radiative forcing (DARF), however, is largely unknown. To quantify changes in the time-averaged DARF, we perform an assessment of 29 days of high temporal resolution ground-based data collected during the Two-Column Aerosol Project (TCAP) on Cape Cod, which is downwind of metropolitan areas. We demonstrate that strong diurnal changes of aerosol loading (about 20% on average) have a negligible impact on the 24-h average DARF, when daily averaged optical properties are used to find this quantity. However, when there is a sparse temporal sampling of aerosol properties, which may preclude the calculation of daily averaged optical properties, large errors (up to 100%) in the computed DARF may occur. We describe a simple way of reducing these errors, which suggests the minimal temporal sampling needed to accurately find the forcing.

  13. De-noising Diurnal Variation Data in Geomagnetic Field Modelling

    NASA Astrophysics Data System (ADS)

    Onovughe, E.

    2017-01-01

    Ground based geomagnetic observatory series have been used to investigate and describe the residuals between a continuous geomagnetic field model and observed diurnal variation for noise-removal of signal due to external field of magnetospheric ring current sources. In all the observatories studied, the residuals in the X-direction consistently show the noisiest signal. Results show that the residuals in the X-direction correlates closely with the RC-index, suggesting an origin from unmodelled external field variation. Notable cross-correlation is also seen between the residuals and the RC-index at zero-lag. Removal/reduction of this unmodelled signal enhances resolution of fine-scale detail in diurnal variation studies.

  14. The diurnal tick-tockery of platelet biology.

    PubMed

    Hartley, Paul S

    2012-01-01

    Circadian (∼24 hours) clocks are ubiquitous in nature and are important regulators of behaviour, physiology and metabolism. Circadian clocks can synchronise biological processes with environmental cycles, buffer biological systems to maintain homeostasis and partition mutually antagonistic processes to different temporal spaces within the daily cycle. Clocks act cell-autonomously (intrinsically) and systemically (extrinsically) to coordinate whole organism biology and there is epidemiological evidence indicating that chronic disruption of behavioural rhythms increases the risk of developing cancer and cardiovascular disease. Although the genetic mechanism of the mammalian clock has been largely deciphered, the physiological relevance of clocks often remains elusive. Findings from humans and animal models suggest that the circadian clock and diurnal rhythms have an important role in megakaryopoiesis and the risk of a cardiovascular event. This short review will introduce the mammalian circadian clock and discuss how circadian clocks and diurnal rhythms influence platelet production and function.

  15. Sampling of the Diurnal Cycle of Precipitation using TRMM

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Bell, Thomas L.; Xu, Li-Ming; Starr, David OC. (Technical Monitor)

    2001-01-01

    We examine the temporal sampling of tropical regions using observations from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and Precipitation Radar (PR). We conclude that PR estimates at any one hour, even using three years of data, are inadequate to describe the diurnal cycle of precipitation over regions smaller than 12 degrees, due to high spatial variability in sampling. We show that the optimum period of accumulation is four hours. Diurnal signatures display half as much sampling error when averaged over four hours of local time. A similar pattern of sampling variability is found in the TMI data, despite the TMI's wider swath and increased sampling. These results are verified using an orbital model. The sensitivity of the sampling to satellite altitude is presented, as well as sampling patterns at the new TRMM altitude of 402.5 km.

  16. Combined Effects of Diurnal and Nonsynchronous Surface Stresses on Europa

    NASA Technical Reports Server (NTRS)

    Stempel, M. M.; Pappalardo, R. T.; Wahr, J.; Barr, A. C.

    2004-01-01

    To date, modeling of the surface stresses on Europa has considered tidal, nonsynchronous, and polar wander sources of stress. The results of such models can be used to match lineament orientations with candidate stress patterns. We present a rigorous surface stress model for Europa that will facilitate comparison of principal stresses to lineament orientation, and which will be available in the public domain. Nonsynchronous rotation and diurnal motion contribute to a stress pattern that deforms the surface of Europa. Over the 85-hour orbital period, the diurnal stress pattern acts on the surface, with a maximum magnitude of approximately 0.1 MPa. The nonsynchronous stress pattern sweeps over the surface due to differential rotation of the icy shell relative to the tidally locked interior of the moon. Nonsynchronous stress builds cumulatively with approximately 0.1 MPa per degree of shell rotation.

  17. Validation of Predicted Diurnal and Semi-diurnal Tidal Variations in Polar Motion with GPS-based Observations

    NASA Astrophysics Data System (ADS)

    Desai, Shailen; Sibois, Aurore

    2016-04-01

    In this paper we reconcile predicted diurnal and semi-diurnal tidal variations in polar motion using observations from the Global Positioning System (GPS) space geodetic technique. We demonstrate closure at the level of less than 4 microarcseconds of the budget between our adopted models for predicted polar motion tidal variations and our GPS-based observations. Our GPS-based observations are composed of a 10-year continuous time series of polar motion estimates with 15-minute temporal resolution. Our adopted models account for the contribution from the relative angular momentum of the ocean tides and so-called libration. We compute predicted ocean tide contributions using a modern hydrodynamic model of tide heights and currents that assimilates satellite altimetry data. We use the model for libration effects provided by the current IERS conventions, as taken from Mathews and Bretagnon [2003]. We also show that the currently recommended models from the International Earth Rotation Service (IERS) conventions do not close the budget with respect to our GPS-based observations. In particular, residual diurnal and semidiurnal tidal variations in polar motion are observed when using the current IERS conventions for ocean tide effects and libration. We infer that the root source for these residual tidal variations is errors in the 20-year old model for ocean tide effects from the IERS conventions, and that predicted ocean tide effects from a modern model mitigates these errors. The noise floor of our high-rate GPS-based times series of polar motion is less than 4 microarcseconds in the diurnal and semidiurnal tidal frequency bands, and is well below the level of the predicted effects of both the ocean tide and libration effects. Diurnal and semidiurnal tidal variations in polar motion are predominantly caused by the ocean tides, which have amplitudes of a few hundred microarcseconds. Libration, namely the effect of external luni-solar torques acting on the triaxial Earth

  18. Warm-up affects diurnal variation in power output.

    PubMed

    Taylor, K; Cronin, J B; Gill, N; Chapman, D W; Sheppard, J M

    2011-03-01

    The purpose of this study was to examine whether time of day variations in power output can be accounted for by the diurnal fluctuations existent in body temperature. 8 recreationally trained males (29.8±5.2 yrs; 178.3±5.2 cm; 80.3±6.5 kg) were assessed on 4 occasions following a: (a) control warm-up at 8.00 am; (b) control warm-up at 4.00 pm; (c) extended warm-up at 8.00 am; and, (d) extended warm-up at 4.00 pm. The control warm-up consisted of dynamic exercises and practice jumps. The extended warm-up incorporated a 20 min general warm-up on a stationary bike prior to completion of the control warm-up, resulting in a whole body temperature increase of 0.3±0.2°C. Kinetic and kinematic variables were measured using a linear optical encoder attached to a barbell during 6 loaded counter-movement jumps. Results were 2-6% higher in the afternoon control condition than morning control condition. No substantial performance differences were observed between the extended morning condition and afternoon control condition where body temperatures were similar. Results indicate that diurnal variation in whole body temperature may explain diurnal performance differences in explosive power output and associated variables. It is suggested that warm-up protocols designed to increase body temperature are beneficial in reducing diurnal differences in jump performance.

  19. Seasonal and diurnal variability of Mars water-ice clouds

    NASA Technical Reports Server (NTRS)

    Christensen, Philip R.; Zurek, Richard W.; Jaramillo, L. L.

    1988-01-01

    The diurnal and seasonal behavior of cloud opacity and frequency of occurrence was studied using an atlas of cloud occurrences compiled from the Viking IRTM (Infrared Thermal Mapper) data set. It was found that in some areas the behavior of water appeared to repeat in the zonal mean. However, this interpretation is complicated by both poor coverage and the variability of dust and clouds. As a result, the extent and nature of interannual variability remains unclear.

  20. Electrostimulation Training Effects on diurnal Fluctuations of Neuromuscular Performance.

    PubMed

    Gueldich, H; Zarrouk, N; Chtourou, H; Zghal, F; Sahli, S; Rebai, H

    2017-01-01

    This study examined the effects of electrostimulation (ES) strength training at the same time-of-day on the diurnal fluctuations of maximal voluntary isometric contractions (MVIC) and surface electromyography (EMG). 20 male performed 3 MVICs of knee extension coupled with surface EMG before and after 5 weeks of 3 ES training sessions per week. Each ES training session consisted in 45 isometric contractions. The participants were randomly assigned to either a morning (MTG, 07:00-08:00 h) or an evening (ETG, 17:00-18:00 h) training group. Both groups performed the evaluation tests at 07:00 and 17:00 h. Before ES training, MVIC was significantly higher in the evening compared to the morning for all groups, but there was no significant difference between groups for all EMG parameters. After the ES training, the diurnal variations in MVIC were blunted in the MTG and persisted in the ETG. Significant time-of-day effect was noticed for all EMG parameters but there was no group effect. The elimination of the diurnal fluctuations of MVIC and the appearance of EMG variations by training in the morning hours suggest that neural adaptations are the main source of temporal specificity of neuromuscular performance after ES strength training.

  1. Social isolation and diurnal cortisol patterns in an ageing cohort☆

    PubMed Central

    Stafford, Mai; Gardner, Mike; Kumari, Meena; Kuh, Diana; Ben-Shlomo, Yoav

    2013-01-01

    Summary Background Social isolation may operate as a psychosocial stressor which disrupts functioning of the hypothalamic–pituitary–adrenocortical axis. Methods Using data from the MRC National Survey of Health and Development, we tested whether living alone, not being married and social network size were associated with diurnal cortisol patterns at 60–64 years. We hypothesised that recent onset compared with long-term isolation would be more strongly associated with cortisol awakening response, cortisol decline over the day and evening cortisol. Models were adjusted for sex, smoking, body mass index, alcohol intake, psychological distress and financial difficulties. Results Those widowed within the last three years had a 36% (95%CI 6%, 73%) higher night time cortisol than those who were currently married. Those newly living alone also had a higher night time cortisol and flatter diurnal slope than those living with others. Conclusion Independently of multiple behavioural and psychosocial correlates, recent onset of social isolation is related to diurnal cortisol patterns that increase the risk of morbidity and mortality. PMID:23920224

  2. Cold and hunger induce diurnality in a nocturnal mammal.

    PubMed

    van der Vinne, Vincent; Riede, Sjaak J; Gorter, Jenke A; Eijer, Willem G; Sellix, Michael T; Menaker, Michael; Daan, Serge; Pilorz, Violetta; Hut, Roelof A

    2014-10-21

    The mammalian circadian system synchronizes daily timing of activity and rest with the environmental light-dark cycle. Although the underlying molecular oscillatory mechanism is well studied, factors that influence phenotypic plasticity in daily activity patterns (temporal niche switching, chronotype) are presently unknown. Molecular evidence suggests that metabolism may influence the circadian molecular clock, but evidence at the level of the organism is lacking. Here we show that a metabolic challenge by cold and hunger induces diurnality in otherwise nocturnal mice. Lowering ambient temperature changes the phase of circadian light-dark entrainment in mice by increasing daytime and decreasing nighttime activity. This effect is further enhanced by simulated food shortage, which identifies metabolic balance as the underlying common factor influencing circadian organization. Clock gene expression analysis shows that the underlying neuronal mechanism is downstream from or parallel to the main circadian pacemaker (the hypothalamic suprachiasmatic nucleus) and that the behavioral phenotype is accompanied by phase adjustment of peripheral tissues. These findings indicate that nocturnal mammals can display considerable plasticity in circadian organization and may adopt a diurnal phenotype when energetically challenged. Our previously defined circadian thermoenergetics hypothesis proposes that such circadian plasticity, which naturally occurs in nocturnal mammals, reflects adaptive maintenance of energy balance. Quantification of energy expenditure shows that diurnality under natural conditions reduces thermoregulatory costs in small burrowing mammals like mice. Metabolic feedback on circadian organization thus provides functional benefits by reducing energy expenditure. Our findings may help to clarify relationships between sleep-wake patterns and metabolic phenotypes in humans.

  3. Visualizing Diurnal Population Change in Urban Areas for Emergency Management

    SciTech Connect

    Kobayashi, Tetsuo; Medina, Richard M; Cova, Thomas

    2011-01-01

    There is an increasing need for a quick, simple method to represent diurnal population change in metropolitan areas for effective emergency management and risk analysis. Many geographic studies rely on decennial U.S. Census data that assume that urban populations are static in space and time. This has obvious limitations in the context of dynamic geographic problems. The U.S. Department of Transportation publishes population data at the transportation analysis zone level in fifteen-minute increments. This level of spatial and temporal detail allows for improved dynamic population modeling. This article presents a methodology for visualizing and analyzing diurnal population change for metropolitan areas based on this readily available data. Areal interpolation within a geographic information system is used to create twenty-four (one per hour) population surfaces for the larger metropolitan area of Salt Lake County, Utah. The resulting surfaces represent diurnal population change for an average workday and are easily combined to produce an animation that illustrates population dynamics throughout the day. A case study of using the method to visualize population distributions in an emergency management context is provided using two scenarios: a chemical release and a dirty bomb in Salt Lake County. This methodology can be used to address a wide variety of problems in emergency management.

  4. Novel opsin gene variation in large-bodied, diurnal lemurs.

    PubMed

    Jacobs, Rachel L; MacFie, Tammie S; Spriggs, Amanda N; Baden, Andrea L; Morelli, Toni Lyn; Irwin, Mitchell T; Lawler, Richard R; Pastorini, Jennifer; Mayor, Mireya; Lei, Runhua; Culligan, Ryan; Hawkins, Melissa T R; Kappeler, Peter M; Wright, Patricia C; Louis, Edward E; Mundy, Nicholas I; Bradley, Brenda J

    2017-03-01

    Some primate populations include both trichromatic and dichromatic (red-green colour blind) individuals due to allelic variation at the X-linked opsin locus. This polymorphic trichromacy is well described in day-active New World monkeys. Less is known about colour vision in Malagasy lemurs, but, unlike New World monkeys, only some day-active lemurs are polymorphic, while others are dichromatic. The evolutionary pressures underlying these differences in lemurs are unknown, but aspects of species ecology, including variation in activity pattern, are hypothesized to play a role. Limited data on X-linked opsin variation in lemurs make such hypotheses difficult to evaluate. We provide the first detailed examination of X-linked opsin variation across a lemur clade (Indriidae). We sequenced the X-linked opsin in the most strictly diurnal and largest extant lemur, Indri indri, and nine species of smaller, generally diurnal indriids (Propithecus). Although nocturnal Avahi (sister taxon to Propithecus) lacks a polymorphism, at least eight species of diurnal indriids have two or more X-linked opsin alleles. Four rainforest-living taxa-I. indri and the three largest Propithecus species-have alleles not previously documented in lemurs. Moreover, we identified at least three opsin alleles in Indri with peak spectral sensitivities similar to some New World monkeys.

  5. Diurnal Cycles in Water Quality Across the Periodic Table

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.

    2013-12-01

    Diurnal cycles in water quality can provide important clues to the processes that regulate aquatic chemistry, but they often are masked by longer-term, larger-amplitude variability, making their detection and quantification difficult. Here I outline several methods that can detect diurnal cycles even when they are massively obscured by statistically ill-behaved noise. I demonstrate these methods using high-frequency water quality data from the Plylimon catchment in mid-Wales (Neal et al., 2013; Kirchner and Neal, 2013). Several aspects combine to make the Plynlimon data set unique worldwide. Collected at 7-hour intervals, the Plynlimon data set is much more densely sampled than typical long-term weekly or monthly water quality data. This 7-hour sampling was also continued for two years, much longer than typical intensive sampling campaigns, and the resulting time series encompass a wide range of climatic and hydrological conditions. Furthermore, each sample was analyzed for a wide range of solutes with diverse sources in the natural environment. However, the 7-hour sampling frequency is both coarse and irregular in comparison to diurnal cycles, making their detection and quantification difficult. Nonetheless, the methods outlined here enable detection of statistically significant diurnal cycles in over 30 solutes at Plynlimon, including alkali metals (Li, Na, K, Rb, and Cs), alkaline earths (Be, Mg, Ca, Sr, and Ba), transition metals (Al, Ti, Mn, Fe, Co, Ni, Zn, Mo, Cd, and Pb), nonmetals (B, NO3, Si, As, and Se), lanthanides and actinides (La, Ce, Pr, and U), as well as total dissolved nitrogen (TDN), dissolved organic carbon (DOC), Gran alkalinity, pH, and electrical conductivity. These solutes span every row of the periodic table, and more than six orders of magnitude in concentration. Many of these diurnal cycles are subtle, representing only a few percent, at most, of the total variance in the concentration time series. Nonetheless they are diagnostically

  6. Tropical Cyclone Diurnal Cycle as Observed by TRMM

    NASA Technical Reports Server (NTRS)

    Leppert, Kenneth D., II; Cecil, D. J.

    2015-01-01

    Using infrared satellite data, previous work has shown a consistent diurnal cycle in the pattern of cold cloud tops around mature tropical cyclones. In particular, an increase in the coverage by cold cloud tops often occurs in the inner core of the storm around the time of sunset and subsequently propagates outward to several hundred kilometers over the course of the following day. This consistent cycle may have important implications for structure and intensity changes of tropical cyclones and the forecasting of such changes. Because infrared satellite measurements are primarily sensitive to cloud top, the goal of this study is to use passive and active microwave measurements from the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) and Precipitation Radar (PR), respectively, to examine and better understand the tropical cyclone diurnal cycle throughout a larger depth of the storm's clouds. The National Hurricane Center's best track dataset was used to extract all PR and TMI pixels within 1000 km of each tropical cyclone that occurred in the Atlantic basin between 1998-2011. Then the data was composited according to radius (100-km bins from 0-1000 km) and local standard time (LST; 3-hr bins). Specifically, PR composites involved finding the percentage of pixels with reflectivity greater than or equal to 20 dBZ at various heights (i.e., 2-14 km in increments of 2 km) as a function of radius and time. The 37- and 85- GHz TMI channels are especially sensitive to scattering by precipitation-sized ice in the mid to upper portions of clouds. Hence, the percentage of 37- and 85-GHz polarization corrected temperatures less than various thresholds were calculated using data from all storms as a function of radius and time. For 37 GHz, thresholds of 260 K, 265 K, 270 K, and 275 K were used, and for 85 GHz, thresholds of 200-270 K in increments of 10 K were utilized. Note that convection forced by the interactions of a tropical cyclone with land (e.g., due

  7. Diurnal Reflectance Changes in Vegetation Observed with AVIRIS

    NASA Technical Reports Server (NTRS)

    Vanderbilt, V. C.; Ambrosia, V. G.; Ustin, S. L.

    1998-01-01

    Among the most important short-term dynamic biological processes are diurnal changes in canopy water relations. Plant regulation of water transport through stomatal openings affects other gaseous transport processes, often dramatically decreasing photosynthetic fixation of carbon dioxide during periods of water stress. Water stress reduces stomatal conductance of water vapor through the leaf surface and alters the diurnal timing of stomatal opening. Under non-water stressed conditions, stomates typically open soon after dawn and transpire water vapor throughout the daylight period. During stress periods, stomates may close for part of the day, generally near mid-day. Under prolonged stress conditions, stomatal closure shifts to earlier times during the day; stomates may close by mid-morning and remain closed until the following morning - or remain closed entirely. Under these conditions the relationship between canopy greenness (e.g., measured with a vegetation index or by spectral mixture analysis) and photosynthetic fixation of carbon is lost and the remotely sensed vegetation metric is a poor predictor of gas exchange. Prediction of stomatal regulation and exchange of water and trace gases is critical for ecosystem and climate models to correctly estimate budgets of these gases and understand or predict other processes like gross and net ecosystem primary production. Plant gas exchange has been extensively studied by physiologists at the leaf and whole plant level and by biometeorologists at somewhat larger scales. While these energy driven processes follow a predictable if somewhat asymmetric diurnal cycle dependent on soil water availability and the constraints imposed by the solar energy budget, they are nonetheless difficult to measure at the tree and stand levels using conventional methods. Ecologists have long been interested in the potential of remote sensing for monitoring physiological changes using multi-temporal images. Much of this research has

  8. Future changes in propagating and non-propagating diurnal rainfall over East Asia

    NASA Astrophysics Data System (ADS)

    Huang, Wan-Ru; Wang, S.-Y. Simon

    2016-09-01

    The characteristics of diurnal rainfall in the East Asian continent consist of a propagating regime over the Yangtze River and a non-propagating regime in southeast China. Simulations of these two diurnal rainfall regimes by 18 CMIP5 models were evaluated from the historical experiment of 1981-2005. The evaluation led to the identification of one model, the CMCC-CM that replicated the key characteristics of diurnal rainfall regimes including the propagation of moisture convergence. Using the CMCC-CM to assess the future (2076-2100) change of diurnal evolution and propagation projected by the RCP4.5 experiment, it was found that propagating diurnal rainfall will enhance and expand southward into the non-propagating regime in southeast China. This change in diurnal rainfall is attributed to the intensification of diurnal land-sea thermal contrast over eastern China and the southward shift of the upper-level jet stream over 20°-30°N. Similar projected changes in diurnal rainfall and associated large-scale dynamical mechanisms were also depicted by four other models (GFDL-ESM2G, GFDL-ESM2M, MRI-CGCM3, and MRI-ESM1) showing a higher skill in representing the diurnal rainfall regimes over East Asia. If such model projection holds true, southeast China will experience an increase in the eastward propagating diurnal rainfall, which could further impact Taiwan.

  9. Diurnal cycles in water quality across the periodic table

    NASA Astrophysics Data System (ADS)

    Kirchner, James

    2014-05-01

    Diurnal cycles in water quality can provide important clues to the processes that regulate aquatic chemistry, but they often are masked by longer-term, larger-amplitude variability, making their detection and quantification difficult. Here I outline methods that can detect diurnal cycles even when they are massively obscured by statistically ill-behaved noise. I demonstrate these methods using high-frequency water quality data from the Plylimon catchment in mid-Wales (Neal et al., 2013; Kirchner and Neal, 2013). Several aspects combine to make the Plynlimon data set unique worldwide. Collected at 7-hour intervals, the Plynlimon data set is much more densely sampled than typical long-term weekly or monthly water quality data. This 7-hour sampling was also continued for two years, much longer than typical intensive sampling campaigns, and the resulting time series encompass a wide range of climatic and hydrological conditions. Furthermore, each sample was analyzed for a wide range of solutes with diverse sources in the natural environment. However, the 7-hour sampling frequency is both coarse and irregular in comparison to diurnal cycles, making their detection and quantification difficult. Nonetheless, the methods outlined here enable detection of statistically significant diurnal cycles in over 30 solutes at Plynlimon, including alkali metals (Li, Na, K, Rb, and Cs), alkaline earths (Be, Mg, Ca, Sr, and Ba), transition metals (Al, Ti, Mn, Fe, Co, Ni, Zn, Mo, Cd, and Pb), nonmetals (B, NO3, Si, As, and Se), lanthanides and actinides (La, Ce, Pr, and U), as well as total dissolved nitrogen (TDN), dissolved organic carbon (DOC), Gran alkalinity, pH, and electrical conductivity. These solutes span every row of the periodic table, and more than six orders of magnitude in concentration. Many of these diurnal cycles are subtle, representing only a few percent, at most, of the total variance in the concentration time series. Nonetheless they are diagnostically useful

  10. Validation of the diurnal cycles in atmospheric reanalyses over Antarctic sea ice

    NASA Astrophysics Data System (ADS)

    Tastula, Esa-Matti; Vihma, Timo; Andreas, Edgar L.; Galperin, Boris

    2013-05-01

    diurnal cycles of near-surface meteorological parameters over Antarctic sea ice in six widely used atmospheric reanalyses are validated against observations from Ice Station Weddell. The station drifted from February through May 1992 and provided the most extensive set of meteorological observations ever collected in the Antarctic sea ice zone. For the radiative and turbulent surface fluxes, both the amplitude and shape of the diurnal cycles vary considerably among different reanalyses. Near-surface temperature, specific humidity, and wind speed in the reanalyses all feature small diurnal ranges, which, in most cases, fall within the uncertainties of the observed cycle. A skill score approach revealed the superiority of the ERA-Interim reanalysis in reproducing the observed diurnal cycles. An explanation for the shortcomings in the reanalyses is their failure to capture the diurnal cycle in cloud cover fraction, which leads to errors in other quantities as well. Apart from the diurnal cycles, NCEP-CFSR gave the best error statistics.

  11. Temperature cycles trigger nocturnalism in the diurnal homeotherm Octodon degus.

    PubMed

    Vivanco, Pablo; Rol, Maria Angeles; Madrid, Juan Antonio

    2010-05-01

    Body temperature regulation within a physiological range is a critical factor for guaranteeing the survival of living organisms. The avoidance of high ambient temperatures is a behavioral mechanism used by homeothermic animals living in extreme environmental conditions. As the circadian system is involved in these thermoregulatory responses, precise phase shifts and even complete temporal niche inversion have been reported. Octodon degus, a mainly diurnal rodent from Chile, has the ability to switch its phase preference for locomotor activity to coincide with the availability of a running wheel. The aims of this work are twofold: to determine whether ambient temperature cycles, with high values during the day and low values at night (HLT(a)), can induce nocturnal chronotypes in degus previously characterized as diurnal; and to learn whether HLT(a) cycles are able to act as a zeitgeber in this dual-phase species. To this end, degus were subjected to 24 h HLT(a) cycles under both 12:12 LD and DD conditions. Two experimental groups were used, one with previous wheel running experience and another naïve group, to study the influence of the thermal cycles and previous wheel running experience on the degus' dual-phasing behavior. Temperature cycles (31.3 +/- 1.5 degrees C during the day and 24.2 +/- 1.6 degrees C at night) induced a 100% nocturnalism in previously diurnal individuals. Indeed, both entrainment with nocturnal phase angle to LD and nocturnal rhythmicity induced by masking were observed. Moreover, HLT(a) cycles acted by masking, confining wheel-running activity to the cooler phase under DD conditions, with the naïve group being more sensitive than the experienced one.

  12. A statistical model of diurnal variation in human growth hormone

    NASA Technical Reports Server (NTRS)

    Klerman, Elizabeth B.; Adler, Gail K.; Jin, Moonsoo; Maliszewski, Anne M.; Brown, Emery N.

    2003-01-01

    The diurnal pattern of growth hormone (GH) serum levels depends on the frequency and amplitude of GH secretory events, the kinetics of GH infusion into and clearance from the circulation, and the feedback of GH on its secretion. We present a two-dimensional linear differential equation model based on these physiological principles to describe GH diurnal patterns. The model characterizes the onset times of the secretory events, the secretory event amplitudes, as well as the infusion, clearance, and feedback half-lives of GH. We illustrate the model by using maximum likelihood methods to fit it to GH measurements collected in 12 normal, healthy women during 8 h of scheduled sleep and a 16-h circadian constant-routine protocol. We assess the importance of the model components by using parameter standard error estimates and Akaike's Information Criterion. During sleep, both the median infusion and clearance half-life estimates were 13.8 min, and the median number of secretory events was 2. During the constant routine, the median infusion half-life estimate was 12.6 min, the median clearance half-life estimate was 11.7 min, and the median number of secretory events was 5. The infusion and clearance half-life estimates and the number of secretory events are consistent with current published reports. Our model gave an excellent fit to each GH data series. Our analysis paradigm suggests an approach to decomposing GH diurnal patterns that can be used to characterize the physiological properties of this hormone under normal and pathological conditions.

  13. DIURNAL CHANGES IN THE ACIDITY OF BRYOPHYLLUM CALYCINUM.

    PubMed

    Gustafson, F G

    1925-07-20

    1. It has been shown that there is a diurnal change in the H ion concentration in Bryophyllum calycinum corresponding approximately to the total acidity changes. The H ion concentration increases at night and decreases during the day. 2. Light is the main factor in causing the decrease in acidity, though it also occurs in the dark. but much more slowly. 3. External oxygen tension does not seem to influence the acidity of the plant, nor does it influence the decomposition of the extracted juice.

  14. DIURNAL CHANGES IN THE ACIDITY OF BRYOPHYLLUM CALYCINUM

    PubMed Central

    Gustafson, Felix G.

    1925-01-01

    1. It has been shown that there is a diurnal change in the H ion concentration in Bryophyllum calycinum corresponding approximately to the total acidity changes. The H ion concentration increases at night and decreases during the day. 2. Light is the main factor in causing the decrease in acidity, though it also occurs in the dark. but much more slowly. 3. External oxygen tension does not seem to influence the acidity of the plant, nor does it influence the decomposition of the extracted juice. PMID:19872175

  15. Estimation of soil moisture from diurnal surface temperature observations

    NASA Technical Reports Server (NTRS)

    Vandegriend, A. A.; Camillo, P. J.

    1986-01-01

    A coupled heat and moisture balance model was used to determine the thermal inertia of a grass covered top soil under different meteorological conditions. Relations between thermal inertia and soil moisture were established using the De Vries models for thermal conductivity and heat capacity to relate soil moisture and thermal inertia as a function of soil type. A sensitivity study of the surface roughness length and thermal inertia on diurnal surface temperature shows the necessity of focusing on the night time surface temperature rather than on the day time surface temperature, in order to estimate the soil moisture content of the top soil.

  16. Link between diurnal stem radius changes and tree water relations.

    PubMed

    Zweifel, R; Item, H; Häsler, R

    2001-08-01

    Internal water reserves are depleted and replenished daily, not only in succulent plants, but also in trees. The significance of these changes in tissue water storage for tree water relations was investigated by monitoring diurnal fluctuations in stem radius. In 6-year-old potted Norway spruce (Picea abies (L.) Karst.) trees, whole-tree transpiration rate (T), sap flow at the stem base and fluctuations in stem radius were measured at 10-min intervals over eight successive weeks. The dynamics of diurnal water storage in relation to the daily course of water movement was simulated and the contribution of stored water to T quantified. The finding that, in P. abies, the course of bark water content is linearly coupled to stem radius fluctuations provided the basis for linking stem radius changes to a functional flow and storage model for tree water relations. This model, which consists of physical functions only and is driven by a single input variable (T), accurately simulates the diurnal course of changes in stem radius and water storage of the tree crown and stem. It was concluded that fluctuations were mainly determined by the course of transpiration. The availability of soil water and the degree to which storage tissues were saturated were also factors affecting the diurnal course of stem radius changes. Internally stored water contributed to daily transpiration even in well-watered trees, indicating that stored water plays an important role not only during periods of drought, but whenever water transport occurs within the tree. Needle and bark water reserves were most heavily depleted during transpiration. Together they supplied approximately 10% of daily T on sunny days, and up to 65% on cloudy days. On a daily basis, the crown (mainly needles) contributed approximately eight times more water to T than the stem (mainly bark). The depletion of the two storage pools and the water movements observed in the trees always occurred in the same sequence. In the morning

  17. Diurnal rhythm of melatonin binding in the rat suprachiasmatic nucleus

    SciTech Connect

    Laitinen, J.T.; Castren, E.; Vakkuri, O.; Saavedra, J.M.

    1989-03-01

    We used quantitative in vitro autoradiography to localize and characterize 2-/sup 125/I-melatonin binding sites in the rat suprachiasmatic nuclei in relation to pineal melatonin production. In a light:dark cycle of 12:12 h, binding density exhibited significant diurnal variation with a peak at the dark-light transition and a trough 12 hours later. Saturation studies suggested that the decreased binding at light-dark transition might be due to a shift of the putative melatonin receptor to a low affinity state.

  18. Analysis of Diurnal, Planetary and Mean Wind Activity using TIMED, MF and Meteor Radar Winds

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.; Riggin, Dennis R.

    2003-01-01

    The goals of this research are: 1) To validate TIMED Doppler Interferometer (TIDI) winds using ground-based MF and meteor winds; and 2) To examine short-term (i. e., day-to-day and week-to-week) variability of the diurnal tide. This objective was to have originally been met using comparisons of short-term diurnal tidal determinations from ground-based (GB) winds with planetary-scale diurnal nonmigrating tidal definitions from TIDI winds.

  19. Studies on air-borne fungi at Qena. II. Diurnal fluctuations.

    PubMed

    Abdel-Fattah, H M; Moubasher, A H; Swelim, M A

    1981-01-01

    The air-borne fungi displayed diurnal periodicities. The total count of fungi exhibited double-peaked pattern, one at 6 a.m. and the other at 18 p.m. (the higher). Aspergillus diurnal activities were almost parallel to those of total fungi. Cladosporium showed on main peak at 18 p.m. Penicillium and Alternaria displayed some pattern of diurnal activity and their maxima were observed.

  20. Diurnal variability of the planetary albedo - An appraisal with satellite measurements and general circulation models

    NASA Technical Reports Server (NTRS)

    Potter, G. L.; Cess, R. D.; Minnis, P.; Harrison, E. F.; Ramanathan, V.

    1988-01-01

    An atmospheric radiation model is used here to illustrate several features associated with modeling the diurnal cycle of the planetary albedo. It is found that even for clear regions there appear to be deficiencies in our knowledge of how to model this quantity. The diurnal amplitude factor, defined as the ratio of the diurnally averaged planetary albedo to that at noon, between two GCMs and measurements made from a geostationary satellite. While reasonable consistency is found, the comparisons underscore difficulties associated with converting local-time albedo measurements, as made from sun-synchronous satellites, to diurnally averaged albedos.

  1. A stochastic differential equation model of diurnal cortisol patterns

    NASA Technical Reports Server (NTRS)

    Brown, E. N.; Meehan, P. M.; Dempster, A. P.

    2001-01-01

    Circadian modulation of episodic bursts is recognized as the normal physiological pattern of diurnal variation in plasma cortisol levels. The primary physiological factors underlying these diurnal patterns are the ultradian timing of secretory events, circadian modulation of the amplitude of secretory events, infusion of the hormone from the adrenal gland into the plasma, and clearance of the hormone from the plasma by the liver. Each measured plasma cortisol level has an error arising from the cortisol immunoassay. We demonstrate that all of these three physiological principles can be succinctly summarized in a single stochastic differential equation plus measurement error model and show that physiologically consistent ranges of the model parameters can be determined from published reports. We summarize the model parameters in terms of the multivariate Gaussian probability density and establish the plausibility of the model with a series of simulation studies. Our framework makes possible a sensitivity analysis in which all model parameters are allowed to vary simultaneously. The model offers an approach for simultaneously representing cortisol's ultradian, circadian, and kinetic properties. Our modeling paradigm provides a framework for simulation studies and data analysis that should be readily adaptable to the analysis of other endocrine hormone systems.

  2. Termite mounds harness diurnal temperature oscillations for ventilation

    PubMed Central

    King, Hunter; Ocko, Samuel; Mahadevan, L.

    2015-01-01

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations. PMID:26316023

  3. The Effect of Diurnal Variations on Ionospheric Radio Occultations

    NASA Astrophysics Data System (ADS)

    Yelle, Roger V.; Koskinen, Tommi; Withers, Paul; Schinder, Paul J.; Moses, Julianne I.; Mueller-Wodarg, Ingo

    2016-10-01

    Radio occultations are a powerful technique for the study of atmospheres and ionospheres by planetary spacecraft. For missions to the outer solar system, the occultations always probe the terminator region of the planet. The analysis of radio occultations typically assumes symmetry along the ray path in the horizontal direction about the tangent point. While this is an excellent assumption for the neutral atmosphere where the scale length of horizontal gradients is large, it is suspect for the ionosphere where electron densities decrease rapidly from day to night. Diurnal variations in peak electron density are often several orders of magnitude and may occur over a region of a few degrees. We investigate the consequences of diurnal variations on ionospheric occultations with a ray tracing calculation for the angular deflection and frequency residual of the radio wave. The calculations are based on photochemical/diffusion models for the ionospheres of Saturn and Titan. Differences from analysis based on the assumption of horizontal symmetry are most pronounced in the bottom side ionosphere where chemical time constants are short.

  4. Mars Science Laboratory diurnal moisture observations and column simulations

    NASA Astrophysics Data System (ADS)

    Savijärvi, H. I.; Harri, A.-M.; Kemppinen, O.

    2015-05-01

    Hourly observations of air temperature and relative humidity at 1.6 m height from the surface (T 1.6 m, RH 1.6 m) measured by the Mars Science Laboratory (MSL) Rover Environmental Monitoring Station relative humidity (REMS-H) device are shown for MSL solar days 15-17 and 80-82, augmented with column model simulations. The diurnal range of T 1.6 m was 197-268 K in the first period, RH 1.6 m being small (<1%) in daytime but increasing to 45-49% by sunrise. During the warmer second period the T 1.6 m range was 201-275 K with RH 1.6 m only up to 16% in the morning. The modeled temperatures were quite close to those observed when the local albedo was set to 0.15 and thermal inertia to 300 tiu. The modeled RH 1.6 m was close to that observed when the well-mixed boundary layer values (0-4 km) of the mass mixing ratio q were 28-30 ppmm (suggesting a precipitable water content (PWC) of ~5.5 µm) during the first period and 12 ppmm (PWC of ~2 µm) during the second period. The REMS-H observations indicate systematic diurnal variation in the near-surface mixing ratio.

  5. Seasonal and diurnal characteristics of atmospheric carbonyls in Nanning, China

    NASA Astrophysics Data System (ADS)

    Guo, Songjun; Chen, Mei; Tan, Jihua

    2016-03-01

    For the first time, atmospheric carbonyls were measured to identify seasonal and diurnal variations in Nanning from October 2011 to July 2012. Formaldehyde (6.79 ± 3.39 μg/m3), acetaldehyde (15.81 ± 10.48 μg/m3) and acetone (5.43 ± 6.91 μg/m3) were the three most abundant carbonyls, accounting for ~ 85% of the total carbonyls. The average total concentrations of carbonyls and three abundant carbonyls showed significant high levels in summer compared to those in winter. Diurnal variations suggested that photochemical conditions, combustion of charcoal and straw, and solvent usage are important for the distributions of atmospheric carbonyls. The highest average C1/C2 ratio was observed in summer (0.75) compared to those (0.31-0.70) in other seasons, implying the positive effect of photochemical activities on raising C1/C2 ratio, and the significant low C2/C3 ratio (12.01-18.23) in winter and autumn than those (95.83-24.49) in both spring and summer suggested the important anthropogenic emissions such as charcoal and biomass combustion. O3 formation potentials in summer and spring were significantly higher by ~ 2 times than those in autumn and winter. Formaldehyde and acetaldehyde are the top two carbonyls which contribute 82-97% to total O3 formation potentials.

  6. Termite mounds harness diurnal temperature oscillations for ventilation.

    PubMed

    King, Hunter; Ocko, Samuel; Mahadevan, L

    2015-09-15

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations.

  7. Listening to music affects diurnal variation in muscle power output.

    PubMed

    Chtourou, H; Chaouachi, A; Hammouda, O; Chamari, K; Souissi, N

    2012-01-01

    The purpose of this investigation was to assess the effects of listening to music while warming-up on the diurnal variations of power output during the Wingate test. 12 physical education students underwent four Wingate tests at 07:00 and 17:00 h, after 10 min of warm-up with and without listening to music. The warm-up consisted of 10 min of pedalling at a constant pace of 60 rpm against a light load of 1 kg. During the Wingate test, peak and mean power were measured. The main finding was that peak and mean power improved from morning to afternoon after no music warm-up (p<0.001 and p<0.01, respectively). These diurnal variations disappeared for mean power and persisted with an attenuated morning-evening difference (p<0.05) for peak power after music warm-up. Moreover, peak and mean power were significantly higher after music than no music warm-up during the two times of testing. Thus, as it is a legal method and an additional aid, music should be used during warm-up before performing activities requiring powerful lower limbs' muscles contractions, especially in the morning competitive events.

  8. Diurnal variations in optical depth at Mars: Observations and interpretations

    NASA Technical Reports Server (NTRS)

    Colburn, D. S.; Pollack, J. B.; Haberle, R. M.

    1988-01-01

    Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Optical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combining these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday.

  9. The diurnal and semidiurnal oscillations in meteor winds over Atlanta

    NASA Astrophysics Data System (ADS)

    Ahmed, M. I.; Roper, R. G.

    The wind data collected over Atlanta during the period August 1974-February 1978 using the Georgia Tech Radio Meteor Wind Facility, is analyzed to yield an average picture of the seasonal behavior of its diurnal tides. Both the zonal and meridional components are studied. The vertical structures of these oscillations over Atlanta are compared with similar studies over Garchy, Urbana and Adelaide. For the semidiurnal tide: the vertical structure during winter appears to have a strong latitude dependence, with vertical wavelength increasing with decreasing latitude; in spring, the (2, 4) and (2, 6) modes appear to dominate at all stations; in summer, the behavior is the same at all four locations, characterized by the apparent domination of the (2,2) mode; in autumn, both the Garchy and Atlanta results indicate the presence of a (2,2) mode, while the (2,4) mode appears to dominate over Urbana. The behavior of the diurnal tide is less well defined: during winter, as latitude decreases from Garchy to Atlanta, evanescent and higher order propagating modes seem to dominate; both spring and summer are characterized by a gradual decrease in observed vertical wavelengths as latitude decreases; in northern hemisphere autumn, the fundamental (1, 1) mode appears to dominate, but at Adelaide in southern hemisphere autumn, predominatly evanescent modes are observed.

  10. Modulation Cycles of Galactic Cosmic Ray Diurnal Anisotropy Variation

    NASA Astrophysics Data System (ADS)

    Oh, S. Y.; Yi, Y.; Bieber, J. W.

    2010-03-01

    The diurnal variation of the galactic cosmic ray (GCR) count rates measured by a ground-based neutron monitor (NM) station represents an anisotropic flow of GCR at 1 AU. The variation of the local time of GCR maximum intensity (we call the phase) is thought in general to have a period of two sunspot cycles (22 years). However, other interpretations are also possible. In order to determine the cyclic behavior of GCR anisotropic variation more precisely, we have carried out a statistical study on the diurnal variation of the phase. We examined 54-year data of Huancayo (Haleakala), 40-year data from Rome, and 43-year data from Oulu NM stations using the ‘pile-up’ method and the F-test. We found that the phase variation has two components: of 22-year and 11-year cycles. All NM stations show mainly the 22-year phase variation controlled by the drift effect due to solar polar magnetic field reversal, regardless of their latitudinal location (cut-off rigidity). However, the lower the NM station latitude is (the higher the cut-off rigidity is), the higher is the contribution from the 11-year phase variation controlled by the diffusion effect due to the change in strength of the interplanetary magnetic fields associated with the sunspot cycle.

  11. Diurnal temperature asymmetries and fog at Churchill, Manitoba

    NASA Astrophysics Data System (ADS)

    Gough, William A.; He, Dianze

    2015-07-01

    A variety of methods are available to calculate daily mean temperature. We explore how the difference between two commonly used methods provides insight into the local climate of Churchill, Manitoba. In particular, we found that these differences related closely to seasonal fog. A strong statistically significant correlation was found between the fog frequency (hours per day) and the diurnal temperature asymmetries of the surface temperature using the difference between the min/max and 24-h methods of daily temperature calculation. The relationship was particularly strong for winter, spring and summer. Autumn appears to experience the joint effect of fog formation and the radiative effect of snow cover. The results of this study suggests that subtle variations of diurnality of temperature, as measured in the difference of the two mean temperature methods of calculation, may be used as a proxy for fog detection in the Hudson Bay region. These results also provide a cautionary note for the spatial analysis of mean temperatures using data derived from the two different methods particularly in areas that are fog prone.

  12. Seasonal and diurnal calling patterns of Ross and leopards

    NASA Astrophysics Data System (ADS)

    Rogers, Tracey L.; Rowney, Gayle A.; Ciaglia, Michaela B.; Cato, Douglas H.

    2005-09-01

    The temporal calling patterns of two Antarctic pack ice seals, the leopard and Ross seal, were examined. This included seasonal onset and decline of calling (coinciding with their breeding season) as well as diurnal changes. Understanding of calling behavior has important implications for acoustic surveying, since this allows the number of calls to be related to an index of the number of animals present and to estimate abundance. The monthly changes in diurnal calling and haul-out patterns (measured via satellite telemetry) were compared. Underwater acoustic recordings were made between 14 October 2003 and 10 January 2004 off Mawson, Eastern Antarctica (660 44.243S and 690 48.748E). Recordings were made using an Acoustics Recording Package (ARP by Dr. John Hildebrand, Scripps Institute of Oceanography, La Jolla, CA) which is designed to sit on the seafloor and passively record acoustic signals. The package was deployed at a depth of 1320.7 m. The sampling rate was 500 Hz and the effective bandwidth from 10 to 250 Hz, covering the bandwidth of only the low-frequency calls of the Ross and leopard seal.

  13. Diurnal variations in optical depth at Mars: Observations and interpretations

    NASA Astrophysics Data System (ADS)

    Colburn, D. S.; Pollack, J. B.; Haberle, R. M.

    1988-05-01

    Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Optical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combining these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday.

  14. Role of Carbohydrates in Diurnal Chilling Sensitivity of Tomato Seedlings

    PubMed Central

    King, Ann I.; Joyce, Daryl C.; Reid, Michael S.

    1988-01-01

    Tomato seedlings (Lycopersicon esculentum Mill.) chilled starting at different times during the light/dark cycle were most chilling-sensitive at the end of the dark period (AI King, MS Reid, BD Patterson 1982 Plant Physiol 70: 211-214). Low-temperature tolerance was regained with as little as 10 minutes of light exposure. Low light intensities were less effective than high light intensities in reducing sensitivity, and the length of exposure to light directly influenced sensitivity. Seedlings kept at low night temperatures prior to chilling were also less injured following chilling. Light also restored chilling tolerance to seedlings whose roots were removed. Supplying cut shoots with sucrose, glucose, or fructose reduced chilling sensitivity and largely eliminated the diurnal difference in sensitivity. Endogenous carbohydrate content was correlated with changes in chilling sensitivity; starch and sugar content fell markedly during the dark period. Increased concentrations of sugars were detected 15 minutes after the start of the light period. This evidence all suggests that changes in chilling sensitivity over the diurnal period are regulated by the light cycle. It also suggests that increased sensitivity at the end of the dark period could be due to carbohydrate depletion, and that chilling tolerance following light exposure is likely due to carbohydrate accumulation or closely related events. PMID:16665984

  15. Modeling multi-frequency diurnal backscatter from a walnut orchard

    NASA Technical Reports Server (NTRS)

    Mcdonald, Kyle C.; Dobson, Myron C.; Ulaby, Fawwaz T.

    1991-01-01

    The Michigan Microwave Canopy Scattering Model (MIMICS) is used to model scatterometer data that were obtained during the August 1987 EOS (Earth Observing System) synergism study. During this experiment, truck-based scatterometers were used to measure radar backscatter from a walnut orchard in Fresno County, California. Multipolarized L- and X-band data were recorded for orchard plots for which dielectric and evapotranspiration characteristics were monitored. MIMICS is used to model a multiangle data set in which a single orchard plot was observed at varying impedance angles and a series of diurnal measurements in which backscatter from this same plot was measured continuously over several 24-h periods. MIMICS accounts for variations in canopy backscatter driven by changes in canopy state that occur diurnally as well as on longer time scales. L-band backscatter is dependent not only on properties of the vegetation but also on properties of the underlying soil surface. The behavior of the X-band backscatter is dominated by properties of the tree crowns.

  16. Extensive Regulation of Diurnal Transcription and Metabolism by Glucocorticoids

    PubMed Central

    Schink, Andrea; Gobet, Cédric; Keime, Céline; Poschet, Gernot; Jost, Bernard; Dickmeis, Thomas

    2016-01-01

    Altered daily patterns of hormone action are suspected to contribute to metabolic disease. It is poorly understood how the adrenal glucocorticoid hormones contribute to the coordination of daily global patterns of transcription and metabolism. Here, we examined diurnal metabolite and transcriptome patterns in a zebrafish glucocorticoid deficiency model by RNA-Seq, NMR spectroscopy and liquid chromatography-based methods. We observed dysregulation of metabolic pathways including glutaminolysis, the citrate and urea cycles and glyoxylate detoxification. Constant, non-rhythmic glucocorticoid treatment rescued many of these changes, with some notable exceptions among the amino acid related pathways. Surprisingly, the non-rhythmic glucocorticoid treatment rescued almost half of the entire dysregulated diurnal transcriptome patterns. A combination of E-box and glucocorticoid response elements is enriched in the rescued genes. This simple enhancer element combination is sufficient to drive rhythmic circadian reporter gene expression under non-rhythmic glucocorticoid exposure, revealing a permissive function for the hormones in glucocorticoid-dependent circadian transcription. Our work highlights metabolic pathways potentially contributing to morbidity in patients with glucocorticoid deficiency, even under glucocorticoid replacement therapy. Moreover, we provide mechanistic insight into the interaction between the circadian clock and glucocorticoids in the transcriptional regulation of metabolism. PMID:27941970

  17. Diurnal oscillations of soybean circadian clock and drought responsive genes.

    PubMed

    Marcolino-Gomes, Juliana; Rodrigues, Fabiana Aparecida; Fuganti-Pagliarini, Renata; Bendix, Claire; Nakayama, Thiago Jonas; Celaya, Brandon; Molinari, Hugo Bruno Correa; de Oliveira, Maria Cristina Neves; Harmon, Frank G; Nepomuceno, Alexandre

    2014-01-01

    Rhythms produced by the endogenous circadian clock play a critical role in allowing plants to respond and adapt to the environment. While there is a well-established regulatory link between the circadian clock and responses to abiotic stress in model plants, little is known of the circadian system in crop species like soybean. This study examines how drought impacts diurnal oscillation of both drought responsive and circadian clock genes in soybean. Drought stress induced marked changes in gene expression of several circadian clock-like components, such as LCL1-, GmELF4- and PRR-like genes, which had reduced expression in stressed plants. The same conditions produced a phase advance of expression for the GmTOC1-like, GmLUX-like and GmPRR7-like genes. Similarly, the rhythmic expression pattern of the soybean drought-responsive genes DREB-, bZIP-, GOLS-, RAB18- and Remorin-like changed significantly after plant exposure to drought. In silico analysis of promoter regions of these genes revealed the presence of cis-elements associated both with stress and circadian clock regulation. Furthermore, some soybean genes with upstream ABRE elements were responsive to abscisic acid treatment. Our results indicate that some connection between the drought response and the circadian clock may exist in soybean since (i) drought stress affects gene expression of circadian clock components and (ii) several stress responsive genes display diurnal oscillation in soybeans.

  18. Short communication: Diurnal feeding pattern of lactating dairy cows.

    PubMed

    DeVries, T J; von Keyserlingk, M A G; Beauchemin, K A

    2003-12-01

    The objectives of this research were to: 1) describe the diurnal variation in feed alley attendance patterns of lactating dairy cows, 2) describe the sources of variation in these patterns, and 3) determine the effects of altering the feed push-up schedule on these patterns. An electronic monitoring system was used to record individual cow presence (6-s resolution) at the feed alley for 24 cows housed in a free-stall barn. Cows were subjected to 2 feeding schedules: 1) baseline schedule, where cows were fed at 0600 and 1515 h and feed was pushed closer to the cows at 1100 and 2130 h; and 2) experimental schedule, where 2 additional feed push-ups at 0030 and 0330 h were added to the baseline schedule. With the data collected from the monitoring system, description of the feed alley attendance patterns on a per minute basis of the group of cows was undertaken. Feed alley attendance was consistently higher during the day and early evening compared with the late night and early morning hours. The greatest percentage of cows attending the feed alley was seen after the delivery of fresh feed and the return from milking. The addition of extra feed push-ups in the early morning hours did little to increase feeding activity. It can be concluded that milking and delivery of fresh feed had a much greater affect on the diurnal pattern of feed alley attendance than did the feed push-ups.

  19. Annual and diurnal african biomass burning temporal dynamics

    NASA Astrophysics Data System (ADS)

    Roberts, G.; Wooster, M. J.; Lagoudakis, E.

    2009-05-01

    Africa is the single largest continental source of biomass burning emissions. Here we conduct the first analysis of one full year of geostationary active fire detections and fire radiative power data recorded over Africa at 15-min temporal interval and a 3 km sub-satellite spatial resolution by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) imaging radiometer onboard the Meteosat-8 satellite. We use these data to provide new insights into the rates and totals of open biomass burning over Africa, particularly into the extremely strong seasonal and diurnal cycles that exist across the continent. We estimate peak daily biomass combustion totals to be 9 and 6 million tonnes of fuel per day in the northern and southern hemispheres respectively, and total fuel consumption between February 2004 and January 2005 is estimated to be at least 855 million tonnes. Analysis is carried out with regard to fire pixel temporal persistence, and we note that the majority of African fires are detected only once in consecutive 15 min imaging slots. An investigation of the variability of the diurnal fire cycle is carried out with respect to 20 different land cover types, and whilst differences are noted between land covers, the fire diurnal cycle characteristics for most land cover type are very similar in both African hemispheres. We compare the Fire Radiative Power (FRP) derived biomass combustion estimates to burned-areas, both at the scale of individual fires and over the entire continent at a 1-degree scale. Fuel consumption estimates are found to be less than 2 kg/m2 for all land cover types noted to be subject to significant fire activity, and for savanna grasslands where literature values are commonly reported the FRP-derived median fuel consumption estimate of 300 g/m2 is well within commonly quoted values. Meteosat-derived FRP data of the type presented here is now available freely to interested users continuously and in near real-time for Africa, Europe and parts

  20. 40 CFR 1060.525 - How do I test fuel systems for diurnal emissions?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... measure diurnal emissions: (1) Diurnal measurements are based on a representative temperature cycle. For marine fuel tanks, the temperature cycle specifies fuel temperatures rather than ambient temperatures. The applicable temperature cycle is indicated in the following table: Table 1 to §...

  1. 40 CFR 1060.525 - How do I test fuel systems for diurnal emissions?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... measure diurnal emissions: (1) Diurnal measurements are based on a representative temperature cycle. For marine fuel tanks, the temperature cycle specifies fuel temperatures rather than ambient temperatures. The applicable temperature cycle is indicated in the following table: Table 1 to §...

  2. The influence of diurnal temperature variation on degree-day accumulation and insect life history.

    PubMed

    Chen, Shi; Fleischer, Shelby J; Saunders, Michael C; Thomas, Matthew B

    2015-01-01

    Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range independent of the mean temperature can affect development rate and voltinism, with the magnitude of the effects dependent on whether changes occur to the daily minimum temperature (Tmin), daily maximum temperature (Tmax), or both. Allowing for an increase in mean temperature produces more marked effects on life history but, again, the patterns and magnitude depend on the nature of the change to diurnal temperature range together with the starting conditions in the local environment. The study highlights the importance of characterizing the influence of diurnal temperature range in addition to mean temperature alone.

  3. Seasonal and spatial patterns in diurnal cycles in streamflow in the western United States

    USGS Publications Warehouse

    Lundquist, J.D.; Cayan, D.R.

    2002-01-01

    The diurnal cycle in streamflow constitutes a significant part of the variability in many rivers in the western United States and can be used to understand some of the dominant processes affecting the water balance of a given river basin. Rivers in which water is added diurnally, as in snowmelt, and rivers in which water is removed diurnally, as in evapotranspiration and infiltration, exhibit substantial differences in the timing, relative magnitude, and shape of their diurnal flow variations. Snowmelt-dominated rivers achieve their highest sustained flow and largest diurnal fluctuations during the spring melt season. These fluctuations are characterized by sharp rises and gradual declines in discharge each day. In large snowmelt-dominated basins, at the end of the melt season, the hour of maximum discharge shifts to later in the day as the snow line retreats to higher elevations. Many evapotranspiration/infiltration-dominated rivers in the western states achieve their highest sustained flows during the winter rainy season but exhibit their strongest diurnal cycles during summer months, when discharge is low, and the diurnal fluctuations compose a large percentage of the total flow. In contrast to snowmelt-dominated rivers, the maximum discharge in evapotranspiration/infiltration-dominated rivers occurs consistently in the morning throughout the summer. In these rivers, diurnal changes are characterized by a gradual rise and sharp decline each day.

  4. Nonmigrating diurnal tide long term variability observed by the TIMED Doppler Interferometer (TIDI)

    NASA Astrophysics Data System (ADS)

    Wu, Q.; Killeen, T. L.; Solomon, S. C.; Ortland, D. A.; Skinner, W. R.; Niciejewski, R. J.

    2007-12-01

    We will examine the temporal variations of nonmigrating diurnal tide in the mesosphere and lower thermosphere using the TIMED Doppler interferometer neutral wind data. The stratosphere QBO is the major source for the interannual variability of migrating tide in the mesosphere and lower thermosphere. There are reports of the possible QBO related the nonmigrating diurnal tide interannual variabilities. Buy examine the tidal variations using spectral analysis method, we plan to examine long term variations in the nonmigrating diurnal tides beyond these related to the QBO. The TIDI data will allow us to examine the diurnal tide variation at different latitudes and altitudes. We will also examine changes in the mean zonal winds in search of possible connection between mean zonal wind and nonmigrating diurnal tides.

  5. Reducing severe diurnal bruxism in two profoundly retarded females.

    PubMed Central

    Blount, R L; Drabman, R S; Wilson, N; Stewart, D

    1982-01-01

    Several diurnal audible teeth grinding (bruxism) was found to affect 21.5% of a profoundly retarded population. However, no previous research has treated bruxism in retarded individuals. In the current study a multiple baseline across subjects design was used to assess the effectiveness of contingent "icing," brief contingent tactile applications of ice, as a treatment for bruxism. Three 15-minute treatment periods and two 5-minute generalization periods were conducted 5 days per week. One resident displayed a 95% reduction in the percentage of intervals during which bruxism occurred during treatment periods and a 67% reduction during generalization periods. The other resident displayed a 94% reduction in the percentage of intervals during which bruxism occurred during treatment periods and a 53% reduction during generalization periods. PMID:6891381

  6. Presumed symbolic use of diurnal raptors by Neanderthals.

    PubMed

    Morin, Eugène; Laroulandie, Véronique

    2012-01-01

    In Africa and western Eurasia, occurrences of burials and utilized ocher fragments during the late Middle and early Late Pleistocene are often considered evidence for the emergence of symbolically-mediated behavior. Perhaps less controversial for the study of human cognitive evolution are finds of marine shell beads and complex designs on organic and mineral artifacts in early modern human (EMH) assemblages conservatively dated to ≈ 100-60 kilo-years (ka) ago. Here we show that, in France, Neanderthals used skeletal parts of large diurnal raptors presumably for symbolic purposes at Combe-Grenal in a layer dated to marine isotope stage (MIS) 5b (≈ 90 ka) and at Les Fieux in stratigraphic units dated to the early/middle phase of MIS 3 (60-40 ka). The presence of similar objects in other Middle Paleolithic contexts in France and Italy suggest that raptors were used as means of symbolic expression by Neanderthals in these regions.

  7. Physical models for the normal YORP and diurnal Yarkovsky effects

    NASA Astrophysics Data System (ADS)

    Golubov, O.; Kravets, Y.; Krugly, Yu. N.; Scheeres, D. J.

    2016-06-01

    We propose an analytic model for the normal Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) and diurnal Yarkovsky effects experienced by a convex asteroid. Both the YORP torque and the Yarkovsky force are expressed as integrals of a universal function over the surface of an asteroid. Although in general this function can only be calculated numerically from the solution of the heat conductivity equation, approximate solutions can be obtained in quadratures for important limiting cases. We consider three such simplified models: Rubincam's approximation (zero heat conductivity), low thermal inertia limit (including the next order correction and thus valid for small heat conductivity), and high thermal inertia limit (valid for large heat conductivity). All three simplified models are compared with the exact solution.

  8. Diurnal variation of wind-chill at Thessaloniki, Greece

    NASA Astrophysics Data System (ADS)

    Balafoutis, Ch. J.

    1989-12-01

    The diurnal variations of wind-chill at Thessaloniki, Greece, are considered using hourly data from January 1960 to December 1977. This is the first attempt in Greece to describe bioclimatic conditions using wind-chill data. The hourly values of wind-chill were calculated by Siple-Passel's formula which still appears to be most widely used. The values of wind-chill are discussed in terms of Terjung's scale. Thessaloniki does not experience “frost-bite” conditions during the coldest months but does experience “warm” conditions during the summer period. A comparison of hourly and daily mean values show that the means do not indicate the real range of wind-chill during the day.

  9. Presumed Symbolic Use of Diurnal Raptors by Neanderthals

    PubMed Central

    Morin, Eugène; Laroulandie, Véronique

    2012-01-01

    In Africa and western Eurasia, occurrences of burials and utilized ocher fragments during the late Middle and early Late Pleistocene are often considered evidence for the emergence of symbolically-mediated behavior. Perhaps less controversial for the study of human cognitive evolution are finds of marine shell beads and complex designs on organic and mineral artifacts in early modern human (EMH) assemblages conservatively dated to ≈100–60 kilo-years (ka) ago. Here we show that, in France, Neanderthals used skeletal parts of large diurnal raptors presumably for symbolic purposes at Combe-Grenal in a layer dated to marine isotope stage (MIS) 5b (≈90 ka) and at Les Fieux in stratigraphic units dated to the early/middle phase of MIS 3 (60–40 ka). The presence of similar objects in other Middle Paleolithic contexts in France and Italy suggest that raptors were used as means of symbolic expression by Neanderthals in these regions. PMID:22403717

  10. Providing Diurnal Sky Cover Data at ARM Sites

    SciTech Connect

    Klebe, Dimitri I.

    2015-03-06

    The Solmirus Corporation was awarded two-year funding to perform a comprehensive data analysis of observations made during Solmirus’ 2009 field campaign (conducted from May 21 to July 27, 2009 at the ARM SGP site) using their All Sky Infrared Visible Analyzer (ASIVA) instrument. The objective was to develop a suite of cloud property data products for the ASIVA instrument that could be implemented in real time and tailored for cloud modelers. This final report describes Solmirus’ research and findings enabled by this grant. The primary objective of this award was to develop a diurnal sky cover (SC) data product utilizing the ASIVA’s infrared (IR) radiometrically-calibrated data and is described in detail. Other data products discussed in this report include the sky cover derived from ASIVA’s visible channel and precipitable water vapor, cloud temperature (both brightness and color), and cloud height inferred from ASIVA’s IR channels.

  11. Diurnal Differences in OLR Climatologies and Anomaly Time Series

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    AIRS (Atmospheric Infrared Sounder) Version-6 OLR (Outgoing Long-Wave Radiation) matches CERES (Clouds and the Earth's Radiant Energy System) Edition-2.8 OLR very closely on a 1x1 latitude x longitude scale, both with regard to absolute values, and also with regard to anomalies of OLR. There is a bias of 3.5 watts per meter squared, which is nearly constant both in time and space. Contiguous areas contain large positive or negative OLR difference between AIRS and CERES are where the day-night difference of OLR is large. For AIRS, the larger the diurnal cycle, the more likely that sampling twice a day is inadequate. Lower values of OLRclr (Clear Sky OLR) and LWCRF (Longwave Cloud Radiative Forcing) in AIRS compared to CERES is at least in part a result of AIRS sampling over cold and cloudy cases.

  12. Melatonin in Epilepsy: A New Mathematical Model of Diurnal Secretion

    PubMed Central

    Kijonka, Marek; Pęcka, Marcin; Sokół, Maria

    2016-01-01

    Purpose. The main objective of the study was to create a mathematical model that describes the melatonin circadian secretion and, then the functionality of the model was tested by a comparison of the melatonin secretions in children with and without epilepsy. Material and Methods. The patients were divided into the epilepsy group (EG, n = 52) and the comparison group (CG, n = 30). The melatonin level was assessed by a radioimmunoassay method. The diurnal melatonin secretion was described using a nonlinear least squares method. Spearman's rank correlation coefficient was chosen to estimate the dependence of the acquired data. The model reproduces blood concentration profiles and its parameters were statistically analyzed using the Mann-Whitney-Wilcoxon test and logistic regression. Results. The correlation analysis performed for the EG and CG groups showed moderate correlations between age and the melatonin secretion model parameters. Patients with epilepsy are characterized by an increased phase shift of melatonin release. PMID:27478439

  13. Diurnal oscillation of SBE expression in sorghum endosperm

    SciTech Connect

    Sun, Chuanxin; Mutisya, J.; Rosenquist, S.; Baguma, Y.; Jansson, C.

    2009-01-15

    Spatial and temporal expression patterns of the sorghum SBEI, SBEIIA and SBEIIB genes, encoding, respectively, starch branching enzyme (SBE) I, IIA and IIB, in the developing endosperm of sorghum (Sorghum bicolor) were studied. Full-length genomic and cDNA clones for sorghum was cloned and the SBEIIA cDNA was used together with gene-specific probes for sorghum SBEIIB and SBEI. In contrast to sorghum SBEIIB, which was expressed primarily in endosperm and embryo, SBEIIA was expressed also in vegetative tissues. All three genes shared a similar temporal expression profile during endosperm development, with a maximum activity at 15-24 days after pollination. This is different from barley and maize where SBEI gene activity showed a significantly later onset compared to that of SBEIIA and SBEIIB. Expression of the three SBE genes in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle.

  14. Diurnal variations of Titan's surface temperatures from Cassini - CIRS observations

    NASA Astrophysics Data System (ADS)

    Cottini, Valeria; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Samuelson, R. E.; Irwin, P. G. J.; Flasar, F. M.

    2010-04-01

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 micron (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the instrument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature profile by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface.

  15. Diurnal emissivity dynamics in bare versus biocrusted sand dunes.

    PubMed

    Rozenstein, Offer; Agam, Nurit; Serio, Carmine; Masiello, Guido; Venafra, Sara; Achal, Stephen; Puckrin, Eldon; Karnieli, Arnon

    2015-02-15

    Land surface emissivity (LSE) in the thermal infrared depends mainly on the ground cover and on changes in soil moisture. The LSE is a critical variable that affects the prediction accuracy of geophysical models requiring land surface temperature as an input, highlighting the need for an accurate derivation of LSE. The primary aim of this study was to test the hypothesis that diurnal changes in emissivity, as detected from space, are larger for areas mostly covered by biocrusts (composed mainly of cyanobacteria) than for bare sand areas. The LSE dynamics were monitored from geostationary orbit by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over a sand dune field in a coastal desert region extending across both sides of the Israel-Egypt political borderline. Different land-use practices by the two countries have resulted in exposed, active sand dunes on the Egyptian side (Sinai), and dunes stabilized by biocrusts on the Israeli side (Negev). Since biocrusts adsorb more moisture from the atmosphere than bare sand does, and LSE is affected by the soil moisture, diurnal fluctuations in LSE were larger for the crusted dunes in the 8.7 μm channel. This phenomenon is attributed to water vapor adsorption by the sand/biocrust particles. The results indicate that LSE is sensitive to minor changes in soil water content caused by water vapor adsorption and can, therefore, serve as a tool for quantifying this effect, which has a large spatial impact. As biocrusts cover vast regions in deserts worldwide, this discovery has repercussions for LSE estimations in deserts around the globe, and these LSE variations can potentially have considerable effects on geophysical models from local to regional scales.

  16. Diurnal variation of oxygen and carbonate system parameters in Tampa Bay and Florida Bay

    USGS Publications Warehouse

    Yates, K.K.; Dufore, C.; Smiley, N.; Jackson, C.; Halley, R.B.

    2007-01-01

    Oxygen and carbonate system parameters were measured, in situ, over diurnal cycles in Tampa Bay and Florida Bay, Florida. All system parameters showed distinct diurnal trends in Tampa Bay with an average range of diurnal variation of 39.1 μmol kg− 1 for total alkalinity, 165.1 μmol kg− 1 for total CO2, 0.22 for pH, 0.093 mmol L− 1 for dissolved oxygen, and 218.1 μatm for pCO2. Average range of diurnal variation for system parameters in Tampa Bay was 73% to 93% of the seasonal range of variability for dissolved oxygen and pH. All system parameters measured in Florida Bay showed distinct variation over diurnal time-scales. However, clear diurnal trends were less evident. The average range of diurnal variability in Florida Bay was 62.8 μmol kg− 1 for total alkalinity, 130.4 μmol kg− 1 for total CO2, 0.13 for pH, 0.053 mmol L− 1 for dissolved oxygen, and 139.8 μatm for pCO2. The average range of diurnal variation was 14% to 102% of the seasonal ranges for these parameters. Diurnal variability in system parameters was most influenced by primary productivity and respiration of benthic communities in Tampa Bay, and by precipitation and dissolution of calcium carbonate in Florida Bay. Our data indicate that use of seasonal data sets without careful consideration of diurnal variability may impart significant error in calculations of annual carbon and oxygen budgets. These observations reinforce the need for higher temporal resolution measurements of oxygen and carbon system parameters in coastal ecosystems.

  17. A survey of the cosmic ray diurnal variation during 1973-1979. I - Persistence of solar diurnal variation. II - Application of diffusion-convection model to diurnal anisotropy data

    NASA Technical Reports Server (NTRS)

    Riker, J. F.; Ahluwalia, H. S.

    1987-01-01

    An analysis of data obtained with the vertical underground muon telescope at Embudo, NM shows that the solar diurnal variation in cosmic ray intensity is a persistent phenomenon over the 1973-1979 period. Assuming that the daily fluctuations in the amplitude and phase of the diurnal variation are random perturbations about the mean vector, the relative magnitude of the random component is determined. In the second part, the Diffusion-Convection model of cosmic ray transport is applied to high rigidity particles detected at the earth in order to deduce the behavior of the heliospheric transport parameters between 1973 and 1979. It is suggested that the diurnal variation observed at Embudo during 1979 may require a contribution from the charged particle drifts.

  18. Work, Stress, and Diurnal Bruxism: A Pilot Study among Information Technology Professionals in Bangalore City, India

    PubMed Central

    Rao, S. K.; Bhat, M.; David, J.

    2011-01-01

    The study assessed the prevalence of diurnal bruxism among information technology (IT) professionals and explored plausible predictors associated with the parafunctional habit. A cross-sectional study was designed and IT professionals were invited to participate. The inclusion criteria composed of participants in service for at least one year, having natural dentition, no history of cervical or facial injury and not undergoing orthodontic therapy. The participants (N = 147) were interviewed by a trained interviewer to record information. A pre-tested questionnaire that included questions related to work, stress symptoms and diurnal bruxism was completed by each participant. The prevalence of self-reported diurnal bruxism was 59%. Bivariate analyses revealed that work (P < 0.05) and work experience (P < 0.05) were significantly associated with self-reported diurnal bruxism. In the binary logistic regression analysis stress (Odds Ratio [OR]  = 5.9, 95% Confidence Interval [CI] 2.6–13.3) was identified to be a strong predictor of diurnal bruxism. Professionals with 11 or more years of experience were less likely to report diurnal bruxism (OR = 0.04, 95% CI 0.00–0.43) than those with 1 to 5 years of work experience. The study revealed that stress and less work experience were associated with diurnal bruxism among IT professionals in Bangalore city. PMID:22190934

  19. Diurnal variation in the effect of the weekend in global seismic activity

    NASA Astrophysics Data System (ADS)

    Ruzhin, Yu. Ya.; Chertoprud, V. E.; Ivanov-Kholodnyi, G. S.

    2016-09-01

    The influence of the earthquake probability diurnal variation on specific features in the weekend effect in global seismic activity is revealed. The dependence of the global earthquake number on the local time and its possible relation to a quiet solar diurnal variation ( Sq) in the geomagnetic field have been considered in detail. It has been indicated that a stable diurnal effect, which has a maximum near midnight and a minimum near local noon, exists in the global seismicity of the Earth. The diurnal variation amplitude changes insignificantly during days of week and substantially decreases (by a factor of almost 3) on Saturday and Sunday. The weekend effect is not revealed during "local nights." Since the daily effect of a quiet solar diurnal variation ( Sq) should not depend on days of week, we arrive at the conclusion that the diurnal variation in global seismicity evidently contains the anthropogenic activity product. The Sunday effect in the earthquake number decreases over the course of time and is most probably real but weak and not stationary since weekly variations occur against a background (or under the action) of stronger variations, i.e., an increase in the earthquake number and diurnal variations.

  20. Contribution of diurnal and nocturnal insects to the pollination of Jatropha curcas (Euphorbiaceae) in southwestern China.

    PubMed

    Luo, Chang W; Huang, Zachary Y; Chen, Xiao M; Li, Kun; Chen, You; Sun, Yong Y

    2011-02-01

    Jatropha curcas L. (Euphorbiaceae) is being increasingly planted worldwide, but questions remain regarding its pollination biology. This study examined the contribution of diurnal and nocturnal insects to the pollination of monoecious J. curcas, through its floral biology, pollination ecology, and foraging behavior of potential pollinators. Nectar production of both male and female flowers peaked in the morning, declined in the afternoon, and rapidly bottomed during the night in all of their anthesis days. The diurnal visitors to the flowers of J. curcas are bees and flies, and the nocturnal visitors are moths. Flowers received significantly more visits by diurnal insects than by nocturnal insects. Through bagging flowers during night or day or both or exclusion, we compared fruit and seed production caused by diurnal and nocturnal pollinators. Both nocturnal and diurnal visitors were successful pollinators. However, flowers exposed only to nocturnal visitors produced less fruits than those exposed only to diurnal visitors. Thus, diurnal pollinators contribute more to seed production by J. curcas at the study site.

  1. Work, Stress, and Diurnal Bruxism: A Pilot Study among Information Technology Professionals in Bangalore City, India.

    PubMed

    Rao, S K; Bhat, M; David, J

    2011-01-01

    The study assessed the prevalence of diurnal bruxism among information technology (IT) professionals and explored plausible predictors associated with the parafunctional habit. A cross-sectional study was designed and IT professionals were invited to participate. The inclusion criteria composed of participants in service for at least one year, having natural dentition, no history of cervical or facial injury and not undergoing orthodontic therapy. The participants (N = 147) were interviewed by a trained interviewer to record information. A pre-tested questionnaire that included questions related to work, stress symptoms and diurnal bruxism was completed by each participant. The prevalence of self-reported diurnal bruxism was 59%. Bivariate analyses revealed that work (P < 0.05) and work experience (P < 0.05) were significantly associated with self-reported diurnal bruxism. In the binary logistic regression analysis stress (Odds Ratio [OR]  = 5.9, 95% Confidence Interval [CI] 2.6-13.3) was identified to be a strong predictor of diurnal bruxism. Professionals with 11 or more years of experience were less likely to report diurnal bruxism (OR = 0.04, 95% CI 0.00-0.43) than those with 1 to 5 years of work experience. The study revealed that stress and less work experience were associated with diurnal bruxism among IT professionals in Bangalore city.

  2. Evidence for a GPR18 Role in Diurnal Regulation of Intraocular Pressure

    PubMed Central

    Miller, Sally; Leishman, Emma; Oehler, Olivia; Daily, Laura; Murataeva, Natalia; Wager-Miller, Jim; Bradshaw, Heather; Straiker, Alex

    2016-01-01

    Purpose The diurnal cycling of intraocular pressure (IOP) was first described in humans more than a century ago. This cycling is preserved in other species. The physiologic underpinning of this diurnal variation in IOP remains a mystery, even though elevated pressure is indicated in most forms of glaucoma, a common cause of blindness. Once identified, the system that underlies diurnal variation would represent a natural target for therapeutic intervention. Methods Using normotensive mice, we measured the regulation of ocular lipid species by the enzymes fatty acid amide hydrolase (FAAH) and N-arachidonoyl phosphatidylethanolamine phospholipase (NAPE-PLD), mRNA expression of these enzymes, and their functional role in diurnal regulation of IOP. Results We now report that NAPE-PLD and FAAH mice do not exhibit a diurnal cycling of IOP. These enzymes produce and break down acylethanolamines, including the endogenous cannabinoid anandamide. The diurnal lipid profile in mice shows that levels of most N-acyl ethanolamines and, intriguingly, N-arachidonoyl glycine (NAGly), decline at night: NAGly is a metabolite of arachidonoyl ethanolamine and a potent agonist at GPR18 that lowers intraocular pressure. The GPR18 blocker O1918 raises IOP during the day when pressure is low, but not at night. Quantitative PCR analysis shows that FAAH mRNA levels rise with pressure, suggesting that FAAH mediates the changes in pressure. Conclusions Our results support FAAH-dependent NAGly action at GPR18 as the physiologic basis of the diurnal variation of intraocular pressure in mice. PMID:27893106

  3. Sensitivity of Amazonian TOA flux diurnal cycle composite monthly variability to choice of reanalysis

    NASA Astrophysics Data System (ADS)

    Dodson, J. Brant; Taylor, Patrick C.

    2016-05-01

    Amazonian deep convection experiences a strong diurnal cycle driven by the cycle in surface sensible heat flux, which contributes to a significant diurnal cycle in the top of the atmosphere (TOA) radiative flux. Even when accounting for seasonal variability, the TOA flux diurnal cycle varies significantly on the monthly timescale. Previous work shows evidence supporting a connection between variability in the convective and radiative cycles, likely modulated by variability in monthly atmospheric state (e.g., convective instability). The hypothesized relationships are further investigated with regression analysis of the radiative diurnal cycle and atmospheric state using additional meteorological variables representing convective instability and upper tropospheric humidity. The results are recalculated with three different reanalyses to test the reliability of the results. The radiative diurnal cycle sensitivity to upper tropospheric humidity is about equal in magnitude to that of convective instability. In addition, the results are recalculated with the data subdivided into the wet and dry seasons. Overall, clear-sky radiative effects have a dominant role in radiative diurnal cycle variability during the dry season. Because of this, even in a convectively active region, the clear-sky radiative effects must be accounted for in order to fully explain the monthly variability in diurnal cycle. Finally, while there is general agreement between the different reanalysis-based results when examining the full data time domain (without regard to time of year), there are significant disagreements when the data are divided into wet and dry seasons. The questionable reliability of reanalysis data is a major limitation.

  4. Sensitivity of Amazonian TOA flux diurnal cycle composite monthly variability to choice of reanalysis.

    PubMed

    Dodson, J Brant; Taylor, Patrick C

    2016-05-16

    Amazonian deep convection experiences a strong diurnal cycle driven by the cycle in surface sensible heat flux, which contributes to a significant diurnal cycle in the top of the atmosphere (TOA) radiative flux. Even when accounting for seasonal variability, the TOA flux diurnal cycle varies significantly on the monthly timescale. Previous work shows evidence supporting a connection between variability in the convective and radiative cycles, likely modulated by variability in monthly atmospheric state (e.g., convective instability). The hypothesized relationships are further investigated with regression analysis of the radiative diurnal cycle and atmospheric state using additional meteorological variables representing convective instability and upper tropospheric humidity. The results are recalculated with three different reanalyses to test the reliability of the results. The radiative diurnal cycle sensitivity to upper tropospheric humidity is about equal in magnitude to that of convective instability. In addition, the results are recalculated with the data subdivided into the wet and dry seasons. Overall, clear-sky radiative effects have a dominant role in radiative diurnal cycle variability during the dry season. Because of this, even in a convectively active region, the clear-sky radiative effects must be accounted for in order to fully explain the monthly variability in diurnal cycle. Finally, while there is general agreement between the different reanalysis-based results when examining the full data time domain (without regard to time of year), there are significant disagreements when the data are divided into wet and dry seasons. The questionable reliability of reanalysis data is a major limitation.

  5. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    PubMed

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

  6. Reproducibility of summertime diurnal precipitation over northern Eurasia simulated by CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Hirota, N.; Takayabu, Y. N.

    2015-12-01

    Reproducibility of diurnal precipitation over northern Eurasia simulated by CMIP5 climate models in their historical runs were evaluated, in comparison with station data (NCDC-9813) and satellite data (GSMaP-V5). We first calculated diurnal cycles by averaging precipitation at each local solar time (LST) in June-July-August during 1981-2000 over the continent of northern Eurasia (0-180E, 45-90N). Then we examined occurrence time of maximum precipitation and a contribution of diurnally varying precipitation to the total precipitation.The contribution of diurnal precipitation was about 21% in both NCDC-9813 and GSMaP-V5. The maximum precipitation occurred at 18LST in NCDC-9813 but 16LST in GSMaP-V5, indicating some uncertainties even in the observational datasets. The diurnal contribution of the CMIP5 models varied largely from 11% to 62%, and their timing of the precipitation maximum ranged from 11LST to 20LST. Interestingly, the contribution and the timing had strong negative correlation of -0.65. The models with larger diurnal precipitation showed precipitation maximum earlier around noon. Next, we compared sensitivity of precipitation to surface temperature and tropospheric humidity between 5 models with large diurnal precipitation (LDMs) and 5 models with small diurnal precipitation (SDMs). Precipitation in LDMs showed high sensitivity to surface temperature, indicating its close relationship with local instability. On the other hand, synoptic disturbances were more active in SDMs with a dominant role of the large scale condensation, and precipitation in SDMs was more related with tropospheric moisture. Therefore, the relative importance of the local instability and the synoptic disturbances was suggested to be an important factor in determining the contribution and timing of the diurnal precipitation. Acknowledgment: This study is supported by Green Network of Excellence (GRENE) Program by the Ministry of Education, Culture, Sports, Science and Technology

  7. Diurnal cycling of urban aerosols under different weather regimes

    NASA Astrophysics Data System (ADS)

    Gregorič, Asta; Drinovec, Luka; Močnik, Griša; Remškar, Maja; Vaupotič, Janja; Stanič, Samo

    2016-04-01

    A one month measurement campaign was performed in summer 2014 in Ljubljana, the capital of Slovenia (population 280,000), aiming to study temporal and spatial distribution of urban aerosols and the mixing state of primary and secondary aerosols. Two background locations were chosen for this purpose, the first one in the city center (urban background - KIS) and the second one in the suburban background (Brezovica). Simultaneous measurements of black carbon (BC) and particle number size distribution of submicron aerosols (PM1) were conducted at both locations. In the summer season emission from traffic related sources is expected to be the main local contribution to BC concentration. Concentrations of aerosol species and gaseous pollutants within the planetary boundary layer are controlled by the balance between emission sources of primary aerosols and gases, production of secondary aerosols, chemical reactions of precursor gases under solar radiation and the rate of dilution by mixing within the planetary boundary layer (PBL) as well as with tropospheric air. Only local emission sources contribute to BC concentration during the stable PBL with low mixing layer height, whereas during the time of fully mixed PBL, regionally transported BC and other aerosols can contribute to the surface measurements. The study describes the diurnal behaviour of the submicron aerosol at the urban and suburban background location under different weather regimes. Particles in three size modes - nucleation (< 25 nm, NUM), Aitken (25 - 90 nm, AIM) and accumulation mode (90 - 800 nm, ACM), as well as BC mass concentration were evaluated separately for sunny, cloudy and rainy days, taking into account modelled values of PBL height. Higher particle number and black carbon concentrations were observed at the urban background (KIS) than at the suburban background location (Brezovica). Significant diurnal pattern of total particle concentration and black carbon concentration was observed at both

  8. The impact of the diurnal cycle on the propagation of Madden-Julian Oscillation convection across the Maritime Continent: DIURNAL CYCLE AND MJO

    SciTech Connect

    Hagos, Samson M.; Zhang, Chidong; Feng, Zhe; Burleyson, Casey D.; De Mott, Charlotte; Kerns, Brandon; Benedict, James J.; Martini, Matus N.

    2016-10-08

    Influences of the diurnal cycle of convection on the propagation of the Madden-Julian Oscillation (MJO) across the Maritime Continent (MC) are examined using cloud-permitting regional model simulations and observations. A pair of ensembles of control (CONTROL) and no-diurnal cycle (NODC) simulations of the November 2011 MJO episode are performed. In the CONTROL simulations, the MJO signal is weakened as it propagates across the MC, with much of the convection stalling over the large islands of Sumatra and Borneo. In the NODC simulations, where the incoming shortwave radiation at the top of the atmosphere is maintained at its daily mean value, the MJO signal propagating across the MC is enhanced. Examination of the surface energy fluxes in the simulations indicates that in the presence of the diurnal cycle, surface downwelling shortwave radiation in CONTROL simulations is larger because clouds preferentially form in the afternoon. Furthermore, the diurnal co-variability of surface wind speed and skin temperature results in a larger sensible heat flux and a cooler land surface in CONTROL compared to NODC simulations. An analysis of observations indicates that the modulation of the downwelling shortwave radiation at the surface by the diurnal cycle of cloudiness negatively projects on the MJO intraseasonal cycle and therefore disrupts the propagation of the MJO across the MC.

  9. Is there a twenty year wave in the diurnal anisotropy of cosmic rays?

    NASA Technical Reports Server (NTRS)

    Ahluwalia, H. S.

    1988-01-01

    Data obtained with the Deep River neutron monitor and the underground vertical muon telescope at Embudo for the period 1965-1979 are analyzed. The data show that for 1957-1970 the diurnal anisotropy is unidirectional. During 1971-1979, the diurnal anisotropy consists of two components. One is in the east-west direction and the other is the radial component, with direction along 12:00 LT. The latter attains a maximum amplitude in 1976. No evidence is found for the existence of the twenty year wave in the diurnal anisotropy of cosmic rays.

  10. Measurement of the solar diurnal anisotropy of the cosmic-ray albedo neutron flux

    NASA Astrophysics Data System (ADS)

    Ifedili, S. O.

    1982-03-01

    The solar diurnal anisotropy of the cosmic-ray albedo neutron flux has been measured by a neutron detector on board the OGO-6 satellite. On the average the diurnal amplitudes and phases of the cosmic ray albedo neutron flux (less than or equal to 10 MeV) were respectively 0.18 + or - 0.02% and 15 + or - 1 hr LT, though there were substantial fluctuations of a few days' duration which did not depend on the solar sector structure polarity and a 27-day periodicity in the diurnal amplitudes which was associated with the sun's rotation.

  11. Long term variability in migrating diurnal tide observed by the TIMED Doppler Interferometer (TIDI)

    NASA Astrophysics Data System (ADS)

    Killeen, T. L.; Wu, Q.; Solomon, S. C.; Ortland, D. A.; Skinner, W. R.; Niciejewski, R. J.

    2007-12-01

    We will examine the temporal variations of migrating diurnal tide in the mesosphere and lower thermosphere using the TIMED Doppler interferometer neutral wind data. The stratosphere QBO is the major source for the interannual variability of the migrating tide in the mesosphere and lower thermosphere. Buy examine the tidal variations using spectral analysis method, we plan to examine long term variations in the migrating diurnal tides beyond these related to the QBO. The TIDI data will allow us to examine the diurnal tide variation at different latitudes and altitudes. We will also study stratosphere observations in search of possible connections to changes in the stratosphere.

  12. Wavy and Cycloidal Lineament Formation on Europa from Combined Diurnal and Nonsynchronous Stresses

    NASA Technical Reports Server (NTRS)

    Gleeson, Damhnait; Crawford, Zane; Barr, Amy C.; Mullen, McCall; Pappalardo, Robert T.; Prockter, Louise M.; Stempel, Michelle M.; Wahr, John

    2005-01-01

    In a companion abstract, we show that fractures propagated into combined diurnal and nonsynchronous rotation (NSR) stress fields can be cycloidal, "wavy," or arcuate in planform as the relative proportion of NSR stress in increased. These transitions occur as NSR stress accumulates over approx. 0 to 10 deg of ice shell rotation, for average fracture propagation speeds of approx. 1 to 3 m/s. Here we consider the NSR speed parameter space for these morphological transitions, and explore the effects on cycloids of adding NSR to diurnal stress. Fitting individual Europan lineaments can constrain the combined NSR plus diurnal stress field at the time of formation.

  13. Diurnal Variations of Titan's Surface Temperatures From Cassini -CIRS Observations

    NASA Astrophysics Data System (ADS)

    Cottini, Valeria; Nixon, Conor; Jennings, Don; Anderson, Carrie; Samuelson, Robert; Irwin, Patrick; Flasar, F. Michael

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 m (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the in-strument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature pro-file by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp

  14. Simulation of diurnal thermal energy storage systems: Preliminary results

    NASA Astrophysics Data System (ADS)

    Katipamula, S.; Somasundaram, S.; Williams, H. R.

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  15. Seasonal and diurnal melatonin production in exercising sled dogs.

    PubMed

    Dunlap, Kriya L; Reynolds, Arleigh J; Tosini, Gianluca; Kerr, Wendell W; Duffy, Lawrence K

    2007-08-01

    Melatonin is a hormone that is released from the pineal gland into the blood stream and is controlled by nerve impulses from the suprachiasmatic nuclei. Melatonin synthesis, which is inhibited by light on the mammalian retina, peaks in plasma concentrations during the night. Though still a subject of intense research, melatonin in mammals is known to effect the reproductive system, thyroid function, and adaptations to seasonal changes. Sled dogs in Fairbanks, Alaska (65 degrees N) can be exposed to anywhere from 21 h of daylight in the summer to 4 h in the winter. While light may be the primary factor influencing melatonin production, we hypothesized that exercise may also affect melatonin production. In the current study, sled dogs were used to study seasonal and diurnal variation in melatonin production. Sled dogs by nature are elite athletes and therefore exercise was a focus in the study. Both exercise and non exercise dogs from 2 distinct latitudes were used. The peak in melatonin production was prolonged in high latitude dogs (65 degrees N), compared with lower latitude dogs (45 degrees N). Dogs at both latitudes show a reduction in peak melatonin levels with exercise, and winter melatonin levels in both locations were higher than the summer. Surprisingly, sled dogs in Alaska had lower melatonin levels than sled dogs in New York.

  16. Diurnal variation of airborne pollen at two different heights.

    PubMed

    Alcázar, P; Galán, C; Cariñanos, P; Domínguez-Vilches, E

    1999-01-01

    The diurnal variation in airborne pollen concentrations in the air of Córdoba at two different heights (1.5 m and 15 m) was studied during 2 consecutive years with the help of two Hirst volumetric samplers. According to pollen percentages obtained every hour, we determined whether every taxon studied presented a morning or an afternoon pattern, and whether this model was homogeneous (with a slight difference between the time of maximum and minimum reading) or heterogeneous (with a large difference between the two readings). We observed that the taxa that had many species in the area, such as Plantago, Poaceae, and Chenopodiaceae-Amaranthaceae showed a homogeneous model, while those taxa with few species present, such as Cupressaceae and Urticaceae showed a more heterogeneous model. Furthermore, the pattern of the plants with a large presence in the study area was more heterogeneous at 1.5 m because the pollen collected at this height is released from anthers. In the sampler placed at 15 m we detected airborne pollen, found that the curves were smoother and also observed a slight time delay for the taxa that were highly present in the area of study.

  17. Winter habitat associations of diurnal raptors in Californias Central Valley

    USGS Publications Warehouse

    Pandolrno, E.R.; Herzog, M.P.; Hooper, S.L.; Smith, Z.

    2011-01-01

    The wintering raptors of California's Central Valley are abundant and diverse. Despite this, little information exists on the habitats used by these birds in winter. We recorded diurnal raptors along 19 roadside survey routes throughout the Central Valley for three consecutive winters between 2007 and 2010. We obtained data sufficient to determine significant positive and negative habitat associations for the White-tailed Kite (Elanus leucurus), Bald Eagle {Haliaeetus leucocephalus), Northern Harrier (Circus cyaneus), Red-tailed Hawk (Buteo jamaicensis), Ferruginous Hawk (Buteo regalis), Rough-legged Hawk (Buteo lagopus), American Kestrel (Falco sparverius), and Prairie Falcon (Falco mexicanus). The Prairie Falcon and Ferruginous and Rough-legged hawks showed expected strong positive associations with grasslands. The Bald Eagle and Northern Harrier were positively associated not only with wetlands but also with rice. The strongest positive association for the White-tailed Kite was with wetlands. The Red-tailed Hawk was positively associated with a variety of habitat types but most strongly with wetlands and rice. The American Kestrel, Northern Harrier, and White-tailed Kite were positively associated with alfalfa. Nearly all species were negatively associated with urbanized landscapes, orchards, and other intensive forms of agriculture. The White-tailed Kite, Northern Harrier, Redtailed Hawk, Ferruginous Hawk, and American Kestrel showed significant negative associations with oak savanna. Given the rapid conversion of the Central Valley to urban and intensive agricultural uses over the past few decades, these results have important implications for conservation of these wintering raptors in this region.

  18. Diurnal modulation signal from dissipative hidden sector dark matter

    NASA Astrophysics Data System (ADS)

    Foot, R.; Vagnozzi, S.

    2015-09-01

    We consider a simple generic dissipative dark matter model: a hidden sector featuring two dark matter particles charged under an unbroken U(1) ‧ interaction. Previous work has shown that such a model has the potential to explain dark matter phenomena on both large and small scales. In this framework, the dark matter halo in spiral galaxies features nontrivial dynamics, with the halo energy loss due to dissipative interactions balanced by a heat source. Ordinary supernovae can potentially supply this heat provided kinetic mixing interaction exists with strength ɛ ∼10-9. This type of kinetically mixed dark matter can be probed in direct detection experiments. Importantly, this self-interacting dark matter can be captured within the Earth and shield a dark matter detector from the halo wind, giving rise to a diurnal modulation effect. We estimate the size of this effect for detectors located in the Southern hemisphere, and find that the modulation is large (≳ 10%) for a wide range of parameters.

  19. Diurnal Phototropism in Solar Tracking Leaves of Lavatera cretica

    PubMed Central

    Schwartz, Amnon; Koller, Dov

    1986-01-01

    On a clear day, leaf laminas of Lavatera cretica tracked the solar position throughout the day. The laminar azimuth did not diverge from the solar azimuth by more than 12° from sunrise to sunset. Tracking of the solar elevation started 1 to 2 hours after sunrise and ceased 1 to 2 hours before sunset. On an overcast day, the laminas reoriented horizontally. After sunset, following a clear day, the laminas performed a nocturnal reorientation, with three well defined phases. During the initial phase the laminas relaxed their strained sunset-facing orientation to one perpendicular to their petioles. This equilibrium configuration was maintained throughout the following phase, which was apparently concerned with time-measuring. During the final phase, the laminas reoriented, before sunrise, to a position facing the direction of the anticipated sunrise. This directional information is phototropic and was retained for 3 to 4 diurnal cycles, probably in the pulvinus itself, which is the site of the response. Laminas of plants transferred from sunlight either to darkness, or to a simulated natural photoperiod under overhead illumination, were facing the originally anticipated direction of sunrise at the time of each of the three to four subsequent sunrises (after which they reverted to the dark orientation in darkness, or to the horizontal one with overhead illumination). Cotyledonary laminas required directional information for the nocturnal reorientation during 3 or 4 cycles of simulated sunrise to sunset transitions. PMID:16664701

  20. Diurnal variation of nitric oxide in the upper stratosphere

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Aimedieu, P.; Pirre, M.; Ramaroson, R.; Matthews, W. A.

    1990-01-01

    Two recent measurements of the temporal variation of nitric oxide at constant altitude near 40 km are reported. The observations were made at float altitude with a balloon-borne chemiluminescence detector together with in situ ozone measurements. The first measurement was made at 44 N on September 17, 1987, at an altitude of 40 km from before sunrise until 1000 LT. The second observation was made at the same latitude on June 18, 1988, at 39 km from 0800 to 1230 LT. At an altitude of 40 km, nitric oxide was observed to start increasing very rapidly at sunrise when the solar zenith angle reached about 95 deg. After the rapid initial buildup, the rate of NO increase stabilized for 3 hours at about 1.2 ppbv/hour. Near 1100 LT at 39 km in summer, the NO mixing ratio was observed to become nearly constant. These features of the diurnal variation of NO are in accord with the temporal variation expected from a time-dependent zero-dimensional photochemical model.

  1. Large diurnal temperature range increases bird sensitivity to climate change.

    PubMed

    Briga, Michael; Verhulst, Simon

    2015-11-13

    Climate variability is changing on multiple temporal scales, and little is known of the consequences of increases in short-term variability, particularly in endotherms. Using mortality data with high temporal resolution of zebra finches living in large outdoor aviaries (5 years, 359.220 bird-days), we show that mortality rate increases almost two-fold per 1°C increase in diurnal temperature range (DTR). Interestingly, the DTR effect differed between two groups with low versus high experimentally manipulated foraging costs, reflecting a typical laboratory 'easy' foraging environment and a 'hard' semi-natural environment respectively. DTR increased mortality on days with low minimum temperature in the easy foraging environment, but on days with high minimum temperature in the semi-natural environment. Thus, in a natural environment DTR effects will become increasingly important in a warming world, something not detectable in an 'easy' laboratory environment. These effects were particularly apparent at young ages. Critical time window analyses showed that the effect of DTR on mortality is delayed up to three months, while effects of minimum temperature occurred within a week. These results show that daily temperature variability can substantially impact the population viability of endothermic species.

  2. Diurnal height variations in growth of children: effects of gravity.

    PubMed

    Kobayashi, M; Kobayashi, M; Tanaka, T; Uchiyama, Y; Togo, M

    1999-07-01

    Many specialists in various scientific fields are interested in human growth and development of body sizes of children as a physiological phenomenon. However, our knowledge on human growth has not yet reached a solid foundation and consensus, and at present gravity potential is known to be a lasting condition that influences human lives in various ways. Therefore, more basic research is needed by examining detailed processes of human growth on the earth, with the effect of gravity in prospect. Although modern human growth study is constructed mainly on the basis of observations at one-year intervals, whether such long-interval observations can reveal a true statistical model of human growth is questionable. Togo and Togo (1982, 1989) observed growth in five siblings at one-month intervals for more than 15 years and found fluctuations observed from the start to the end of growth observations consisted of trend, regular, and irregular factors. This indicates the importance of examining human growth by short-interval observation. Thus, our study focused on diurnal variations of height, measuring twice daily, and discusses the effects of gravity on growth of children.

  3. Passive ranging redundancy reduction in diurnal weather conditions

    NASA Astrophysics Data System (ADS)

    Cha, Jae H.; Abbott, A. Lynn; Szu, Harold H.

    2013-05-01

    Ambiguity in binocular ranging (David Marr's paradox) may be resolved by using two eyes moving from side to side behind an optical bench while integrating multiple views. Moving a head from left to right with one eye closed can also help resolve the foreground and background range uncertainty. That empirical experiment implies redundancy in image data, which may be reduced by adopting a 3-D camera imaging model to perform compressive sensing. Here, the compressive sensing concept is examined from the perspective of redundancy reduction in images subject to diurnal and weather variations for the purpose of resolving range uncertainty at all weather conditions such as the dawn or dusk, the daytime with different light level or the nighttime at different spectral band. As an example, a scenario at an intersection of a country road at dawn/dusk is discussed where the location of the traffic signs needs to be resolved by passive ranging to answer whether it is located on the same side of the road or the opposite side, which is under the influence of temporal light/color level variation. A spectral band extrapolation via application of Lagrange Constrained Neural Network (LCNN) learning algorithm is discussed to address lost color restoration at dawn/dusk. A numerical simulation is illustrated along with the code example.

  4. Observations of a "weekend effect" in diurnal temperature range.

    PubMed

    Forster, Piers M de F; Solomon, Susan

    2003-09-30

    Using surface measurements of maximum and minimum temperatures from the Global Daily Climatological Network data set, we find evidence of a weekly cycle in diurnal temperature range (DTR) for many stations in the United States, Mexico, Japan, and China. The "weekend effect," which we define as the average DTR for Saturday through Monday minus the average DTR for Wednesday through Friday, can be as large as 0.5 K, similar to the magnitude of observed long-term trends in DTR. This weekend effect has a distinct large-scale pattern that has changed only slightly over time, but its sign is not the same in all locations. The station procedures and the statistical robustness of both the individual station data and the patterns of DTR differences are thoroughly examined. We conclude that the weekend effect is a real short time scale and large spatial scale geophysical phenomenon, which is necessarily human in origin. We thus provide strong evidence of an anthropogenic link to DTR, an important climate indicator. Several possible anthropogenic mechanisms are discussed; we speculate that aerosol-cloud interactions are the most likely cause of this weekend effect, but we do not rule out others.

  5. Evaluation of the sensitivity of the Amazonian diurnal cycle to convective intensity in reanalyses

    NASA Astrophysics Data System (ADS)

    Itterly, Kyle F.; Taylor, Patrick C.

    2017-02-01

    Model parameterizations of tropical deep convection are unable to reproduce the observed diurnal and spatial variability of convection in the Amazon, which contributes to climatological biases in the water cycle and energy budget. Convective intensity regimes are defined using percentiles of daily minimum 3-hourly averaged outgoing longwave radiation (OLR) from Clouds and the Earth's Radiant Energy System (CERES). This study compares the observed spatial variability of convective diurnal cycle statistics for each regime to MERRA-2 and ERA-Interim (ERA) reanalysis data sets. Composite diurnal cycle statistics are computed for daytime hours (06:00-21:00 local time) in the wet season (December-January-February). MERRA-2 matches observations more closely than ERA for domain averaged composite diurnal statistics—specifically precipitation. However, ERA reproduces mesoscale features of OLR and precipitation phase associated with topography and the propagation of the coastal squall line. Both reanalysis models are shown to underestimate extreme convection.

  6. Glucocorticoid regulation of ATP release from spinal astrocytes underlies diurnal exacerbation of neuropathic mechanical allodynia.

    PubMed

    Koyanagi, Satoru; Kusunose, Naoki; Taniguchi, Marie; Akamine, Takahiro; Kanado, Yuki; Ozono, Yui; Masuda, Takahiro; Kohro, Yuta; Matsunaga, Naoya; Tsuda, Makoto; Salter, Michael W; Inoue, Kazuhide; Ohdo, Shigehiro

    2016-10-14

    Diurnal variations in pain hypersensitivity are common in chronic pain disorders, but the underlying mechanisms are enigmatic. Here, we report that mechanical pain hypersensitivity in sciatic nerve-injured mice shows pronounced diurnal alterations, which critically depend on diurnal variations in glucocorticoids from the adrenal glands. Diurnal enhancement of pain hypersensitivity is mediated by glucocorticoid-induced enhancement of the extracellular release of ATP in the spinal cord, which stimulates purinergic receptors on microglia in the dorsal horn. We identify serum- and glucocorticoid-inducible kinase-1 (SGK-1) as the key molecule responsible for the glucocorticoid-enhanced release of ATP from astrocytes. SGK-1 protein levels in spinal astrocytes are increased in response to glucocorticoid stimuli and enhanced ATP release by opening the pannexin-1 hemichannels. Our findings reveal an unappreciated circadian machinery affecting pain hypersensitivity caused by peripheral nerve injury, thus opening up novel approaches to the management of chronic pain.

  7. Effect of suprachiasmatic lesions on diurnal heart rate rhythm in the rat

    NASA Technical Reports Server (NTRS)

    Saleh, M. A.; Winget, C. M.

    1977-01-01

    Heart rate and locomotor activity of rats kept under 12L/12D illumination regimen were recorded every six minutes for ten days using implantable radio transmitters. Some of the rats then received bilateral RF lesions into the suprachiasmatic nucleus (SCN). Control sham operations were performed on the rest of the animals. After recovery from surgery, recording of heart rate and locomotor activity was continued for ten days. SCN-lesioned rats showed no significant diurnal fluctuation in heart rate, while normal and sham-operated rats showed the normal diurnal rhythm in that function. The arrhythmic diurnal heart-rate pattern of SCN rats appeared to be correlated with their sporadic activity pattern. The integrity of the suprachiasmatic nucleus is therefore necessary for the generation and/or expression of diurnal rhythmicity in heart rate in the rat.

  8. On the diurnal characteristics of cloud structure in the marine stratocumulus transition regime

    SciTech Connect

    Miller, M.A.

    1996-07-01

    It is known that stratus-topped marine boundary layers in the mid- latitudes are subject to significant diurnal changes in structure caused by solar heating. One characteristic of the transition cloud regime that has been thoroughly explored is its diurnal variability. Although this variability has been discussed in other studies, the size of the database was restrictive. Thus, it is of importance to examine the diurnal characteristics of transition cloud structure in a larger data sample to validate the conclusions of these previous studies and to enhance our understanding of the effects of this diurnal variability on the climatology of the transition itself. The Atlantic Stratocumulus Transition Experiment (ASTEX) was designed to help understand transition clouds by making comprehensive measurements of their structure over a one-month period. Data was collected using a suite of in-situ and surface-based remote sensors deployed on the island of Santa Maria.

  9. Resonant Third-Degree Diurnal Tides in the Seas Off Western Europe

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Smith, David E. (Technical Monitor)

    2000-01-01

    Third-degree diurnal tides are estimated from long time series of sea level measurements at three North Atlantic tide gauges. Although their amplitudes are only a few mm or less, their admittances are far larger than those of second-degree diurnal tides, just as Cartwright discovered for the M(sub 1) constituent. The tides are evidently resonantly enhanced owing to high spatial correlation between the third-degree spherical harmonic of the tidal potential and a near-diurnal oceanic normal mode that is most pronounced in the North Atlantic. By estimating the ocean tidal response across the diurnal band (5 tidal constituents plus nodal modulations), the period and Q of this mode and one nearby mode are estimated.

  10. Linking diurnal cycles of river flow to interannual variations in climate

    USGS Publications Warehouse

    Lundquist, Jessica D.; Dettinger, Michael D.

    2003-01-01

    Many rivers in the Western United States have diurnal variations exceeding 10% of their mean flow in the spring and summer months. The shape and timing of the diurnal cycle is influenced by an interplay of the snow, topography, vegetation, and meteorology in a basin, and the measured result differs between wet and dry years. The largest interannual differences occur during the latter half of the melt season, as the snowline retreats to the highest elevations and most shaded slopes in a basin. In most basins, during this period, the hour of peak discharge shifts to later in the day, and the relative amplitude of the diurnal cycle decreases. The magnitude and rate of these changes in the diurnal cycle vary between years and may provide clues about how long- term hydroclimatic variations affect short-term basin dynamics.

  11. Glucocorticoid regulation of ATP release from spinal astrocytes underlies diurnal exacerbation of neuropathic mechanical allodynia

    PubMed Central

    Koyanagi, Satoru; Kusunose, Naoki; Taniguchi, Marie; Akamine, Takahiro; Kanado, Yuki; Ozono, Yui; Masuda, Takahiro; Kohro, Yuta; Matsunaga, Naoya; Tsuda, Makoto; Salter, Michael W.; Inoue, Kazuhide; Ohdo, Shigehiro

    2016-01-01

    Diurnal variations in pain hypersensitivity are common in chronic pain disorders, but the underlying mechanisms are enigmatic. Here, we report that mechanical pain hypersensitivity in sciatic nerve-injured mice shows pronounced diurnal alterations, which critically depend on diurnal variations in glucocorticoids from the adrenal glands. Diurnal enhancement of pain hypersensitivity is mediated by glucocorticoid-induced enhancement of the extracellular release of ATP in the spinal cord, which stimulates purinergic receptors on microglia in the dorsal horn. We identify serum- and glucocorticoid-inducible kinase-1 (SGK-1) as the key molecule responsible for the glucocorticoid-enhanced release of ATP from astrocytes. SGK-1 protein levels in spinal astrocytes are increased in response to glucocorticoid stimuli and enhanced ATP release by opening the pannexin-1 hemichannels. Our findings reveal an unappreciated circadian machinery affecting pain hypersensitivity caused by peripheral nerve injury, thus opening up novel approaches to the management of chronic pain. PMID:27739425

  12. New fire diurnal cycle characterizations to improve fire radiative energy assessments made from MODIS observations

    NASA Astrophysics Data System (ADS)

    Andela, N.; Kaiser, J. W.; van der Werf, G. R.; Wooster, M. J.

    2015-08-01

    Accurate near real time fire emissions estimates are required for air quality forecasts. To date, most approaches are based on satellite-derived estimates of fire radiative power (FRP), which can be converted to fire radiative energy (FRE) which is directly related to fire emissions. Uncertainties in these FRE estimates are often substantial. This is for a large part because the most often used low-Earth orbit satellite-based instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) have a relatively poor sampling of the usually pronounced fire diurnal cycle. In this paper we explore the spatial variation of this fire diurnal cycle and its drivers using data from the geostationary Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI). In addition, we sampled data from the SEVIRI instrument at MODIS detection opportunities to develop two approaches to estimate hourly FRE based on MODIS active fire detections. The first approach ignored the fire diurnal cycle, assuming persistent fire activity between two MODIS observations, while the second approach combined knowledge on the climatology of the fire diurnal cycle with active fire detections to estimate hourly FRE. The full SEVIRI time series, providing full coverage of the fire diurnal cycle, were used to evaluate the results. Our study period comprised of 3 years (2010-2012), and we focused on Africa and the Mediterranean basin to avoid the use of potentially lower quality SEVIRI data obtained at very far off-nadir view angles. We found that the fire diurnal cycle varies substantially over the study region, and depends on both fuel and weather conditions. For example, more "intense" fires characterized by a fire diurnal cycle with high peak fire activity, long duration over the day, and with nighttime fire activity are most common in areas of large fire size (i.e., large burned area per fire event). These areas are most prevalent in relatively arid regions. Ignoring the fire diurnal

  13. Characteristics of high energy cosmic ray diurnal anisotropy on day-to-day basis

    NASA Astrophysics Data System (ADS)

    Tiwari, C. M.; Tiwari, D. P.

    2008-10-01

    Diurnal variation of cosmic ray intensity for the period of 1989 to 2000 at Kiel, Haleakakla, Rome, Hermanus, Calgary, and Goose Bay neutron monitors has been studied. Frequency histograms are generated for each year by using the daily values of amplitudes and phases. In the present analysis we have derived the yearly mean amplitude and phase of the diurnal variation of cosmic ray intensity. It has been concluded from the analysis that the diurnal amplitude is mostly concentrated in between the amplitude values of 0.1% and 0.4%, whereas the phase of diurnal anisotropy is concentrated in the belt of 100 to 225 degrees. As such, the various characteristics of long-term diurnal variation of cosmic ray intensity for the maxima of solar activity cycle 22 to the next maxima of solar activity cycle 23 have been studied. The minimum amplitudes are apparent for the minimum solar activity periods starting from 1995 and up to 1997 at Kiel, Haleakakla, Rome, Hermanus, Calgary and Goose Bay stations. The diurnal amplitude has been found to have almost recovered to its values observed during 1989 to 1990. It is also seen that the diurnal amplitudes are much larger by a factor of two at high/middle latitude stations as compared to that for low latitude stations, where the amplitudes are even ˜01% or less during 1996. The phase is significantly earlier during 1996 and 1997 with some significant change starting in 1995. As such, competitive is a continuous decreasing trend in the diurnal phase with smaller change at high/middle latitude and significantly much larger change at low latitudes.

  14. Diurnal centroid of ecosystem energy and carbon fluxes at FLUXNET sites

    NASA Astrophysics Data System (ADS)

    Wilson, Kell B.; Baldocchi, Dennis; Falge, Eva; Aubinet, Marc; Berbigier, Paul; Bernhofer, Christian; Dolman, Han; Field, Chris; Goldstein, Allen; Granier, Andre; Hollinger, Dave; Katul, Gabriel; Law, B. E.; Meyers, Tilden; Moncrieff, John; Monson, Russ; Tenhunen, John; Valentini, Riccardo; Verma, Shashi; Wofsy, Steve

    2003-11-01

    Data from a network of eddy covariance stations in Europe and North America (FLUXNET) were analyzed to examine the diurnal patterns of surface energy and carbon fluxes during the summer period across a range of ecosystems and climates. Diurnal trends were quantified by assessing the time of day surface fluxes and meteorological variable reached peak values, using the "diurnal centroid" method; the diurnal centroid enabled us to discern whether the peak activity of the variable of interest is weighted more toward the morning or afternoon. In this paper, diurnal centroid estimates were used to diagnose which atmospheric and physiological processes controlled carbon dioxide, water vapor, and sensible heat fluxes across different ecosystems and climates. Sensitivity tests suggested that the diurnal centroids for latent (LE) and sensible (H) heat flux depend on atmospheric resistance, static stability in the free atmosphere, stomatal response to vapor pressure deficit, and advection. With respect to diurnal trends of surface energy fluxes at FLUXNET sites, maximum LE occurred later in the day relative to H at most tall forests with continental climates. The lag between LE and H was reduced or reversed at sites that were influenced by advection or by afternoon stomatal closure. The time of peak carbon uptake of temperate forests occurred earlier relative to the temporal peak of photosynthetically active radiation, as compared to boreal forests. The timing of this peak occurred earlier during periods with low soil water content, as it did during the summer in Mediterranean climates. In this case, the diurnal centroid for the CO2 flux was influenced by the response of respiration and photosynthesis to increasing afternoon temperature and by afternoon stomatal closure.

  15. [Diurnal and seasonal variations of surface atmospheric CO2 concentration in the river estuarine marsh].

    PubMed

    Zhang, Lin-Hai; Tong, Chuan; Zeng, Cong-Sheng

    2014-03-01

    Characteristics of diurnal and seasonal variations of surface atmospheric CO2 concentration were analyzed in the Minjiang River estuarine marsh from December 2011 to November 2012. The results revealed that both the diurnal and seasonal variation of surface atmospheric CO2 concentration showed single-peak patterns, with the valley in the daytime and the peak value at night for the diurnal variations, and the maxima in winter and minima in summer for the seasonal variation. Diurnal amplitude of CO2 concentration varied from 16.96 micromol x mol(-1) to 38.30 micromol x mol(-1). The seasonal averages of CO2 concentration in spring, summer, autumn and winter were (353.74 +/- 18.35), (327.28 +/- 8.58), (354.78 +/- 14.76) and (392.82 +/- 9.71) micromol x mol(-1), respectively, and the annual mean CO2 concentration was (357.16 +/- 26.89) micromol x mol(-1). The diurnal CO2 concentration of surface atmospheric was strongly negatively correlated with temperature, wind speed, photosynthetically active radiation and total solar radiation (P < 0.05). The diurnal concentration of CO2 was negatively related with tidal level in January, but significantly positively related in July.

  16. Seasonal resonance of diurnal coastal trapped waves in the southern Weddell Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Semper, Stefanie; Darelius, Elin

    2017-01-01

    The summer enhancement of diurnal tidal currents at the shelf break in the southern Weddell Sea is studied using velocity measurements from 29 moorings during the period 1968 to 2014. Kinetic energy associated with diurnal tidal frequencies is largest at the shelf break and decreases rapidly with distance from it. The diurnal tidal energy increases from austral winter to summer by, on average, 50 %. The austral summer enhancement is observed in all deployments. The observations are compared to results from an idealised numerical solution of the properties of coastal trapped waves (CTWs) for a given bathymetry, stratification and an along-slope current. The frequency at which the dispersion curve for mode 1 CTWs displays a maximum (i.e. where the group velocity is zero and resonance is possible) is found within or near the diurnal frequency band, and it is sensitive to the stratification in the upper part of the water column and to the background current. The maximum of the dispersion curve is shifted towards higher frequencies, above the diurnal band, for weak stratification and a strong background current (i.e. austral winter-like conditions) and towards lower frequencies for strong upper-layer stratification and a weak background current (austral summer). The seasonal evolution of hydrography and currents in the region is inferred from available mooring data and conductivity-temperature-depth profiles. Near-resonance of diurnal tidal CTWs during austral summer can explain the observed seasonality in tidal currents.

  17. Mixing by semi-diurnal internal waves in the Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Jensen, T. G.; Wijesekera, H. W.

    2015-12-01

    Strong internal waves generated by tides found to propagate into the Bay of Bengal from their generation in the straits in Andaman Islands Archipelago. The waves has been observed in Synthetic Aperture Radar data, and appear as solitary wave packets. They are also present in subsurface temperature records from the RAMA mooring s. In this work the waves are simulated by a fully coupled ocean-atmosphere prediction system, exchanging surface fluxes between the air and sea at high frequency and high resolution. The ocean model includes diurnal and semi-diurnal tides and has a 2 km resolution in the entire Bay of Bengal. In the model simulations, large amplitude semi-diurnal internal waves interact with the meso-scale circulation and modify the flow and the stratification as far away as Sri Lanka. By comparing model runs with tides and without tides, but forced by identical surface fluxes from the atmosphere, we find that the inclusion of diurnal and semi-diurnal tides act to cool the thermocline due to vertical mixing. This imply that non-linear semi-diurnal internal waves may significantly contribute to mixing in the interior of the Bay of Bengal.

  18. Salt overly sensitive pathway members are influenced by diurnal rhythm in rice.

    PubMed

    Soni, Praveen; Kumar, Gautam; Soda, Neelam; Singla-Pareek, Sneh L; Pareek, Ashwani

    2013-07-01

    The diurnal rhythm controls many aspects of plant physiology such as flowering, photosynthesis and growth. Rice is one of the staple foods for world's population. Abiotic stresses such as salinity, drought, heat and cold severely affect rice production. Under salinity stress, maintenance of ion homeostasis is a major challenge, which also defines the tolerance level of a given genotype. Salt overly sensitive (SOS) pathway is well documented to play a key role in maintaining the Na(+) homeostasis in plant cell. However, it is not reported yet whether the transcriptional regulation of genes of this pathway are influenced by diurnal rhythm. In the present work, we have studied the diurnal pattern of transcript abundance of SOS pathway genes in rice at seedling stage.To rule out the effect of temperature fluctuations on the expression patterns of these genes, the seedlings were grown under constant temperature. We found that OsSOS3 and OsSOS2 exhibited a rhythmic and diurnal expression pattern, while OsSOS1did not have any specific pattern of expression. This analysis establishes a cross-link between diurnal rhythm and SOS pathway and suggests that SOS pathway is influenced by diurnal rhythm in rice.

  19. Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate

    NASA Technical Reports Server (NTRS)

    Mackerras, D.; Darvenzia, M.; Orville, R. E.; Williams, E. R.; Goodman, S. J.

    1999-01-01

    A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approx. = 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approx. = 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves in Universal time (UT) could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels.

  20. Latitudinal and longitudinal dependence of the cosmic ray diurnal anisotropy during 2001-2014

    NASA Astrophysics Data System (ADS)

    Tezari, Anastasia; Mavromichalaki, Helen; Katsinis, Dimitrios; Kanellakopoulos, Anastasios; Kolovi, Sofia; Plainaki, Christina; Andriopoulou, Maria

    2016-11-01

    The diurnal anisotropy of cosmic ray intensity for the time period 2001 to 2014 is studied, covering the maximum and the descending phase of solar cycle 23, the minimum between solar cycles 23 and 24, and the ascending phase and maximum of solar cycle 24. Cosmic ray intensity data from 11 neutron monitor stations located at different places around the Northern Hemisphere obtained from the high-resolution Neutron Monitor Database (NMDB) were used. Special software was developed for the calculations of the amplitude and the phase of the diurnal anisotropy vectors on annual and monthly basis using Fourier analysis and for the creation of the harmonic dial diagrams. The geomagnetic bending for each station was taken into account in our calculations determined from the asymptotic cones of each station via the Tsyganenko96 (Tsyganenko and Stern, 1996) magnetospheric model. From our analysis, it was resulted that there is a different behavior of the diurnal anisotropy vectors during the different phases of the solar cycles depending on the solar magnetic field polarity. The latitudinal and longitudinal distribution of the cosmic ray diurnal anisotropy was also examined by grouping the stations according to their geographic coordinates, and it was shown that diurnal variation is modulated not only by the latitude but also by the longitude of the stations. The diurnal anisotropy during strong events of solar and/or cosmic ray activity is discussed.

  1. Diversity of photoreceptor arrangements in nocturnal, cathemeral and diurnal Malagasy lemurs.

    PubMed

    Peichl, Leo; Kaiser, Alexander; Rakotondraparany, Felix; Dubielzig, Richard R; Goodman, Steven M; Kappeler, Peter M

    2017-01-05

    The lemurs of Madagascar (Primates: Lemuriformes) are a monophyletic group that has lived in isolation from other primates for about 50 million years. Lemurs have diversified into species with diverse daily activity patterns and correspondingly different visual adaptations. We assessed the arrangements of retinal cone and rod photoreceptors in six nocturnal, three cathemeral and two diurnal lemur species and quantified different parameters in six of the species. The analysis revealed lower cone densities and higher rod densities in the nocturnal than in the cathemeral and diurnal species. The photoreceptor densities in the diurnal Propithecus verreauxi indicate a less "diurnal" retina than found in other diurnal primates. Immunolabeling for cone opsins showed the presence of both middle-to-longwave sensitive (M/L) and shortwave sensitive (S) cones in most species, indicating at least dichromatic color vision. S cones were absent in Allocebus trichotis and Cheirogaleus medius, indicating cone monochromacy. In the Microcebus species, the S cones had an inverse topography with very low densities in the central retina and highest densities in the peripheral retina. The S cones in the other species and the M/L cones in all species had a conventional topography with peak densities in the central area. With the exception of the cathemeral Eulemur species, the eyes of all studied taxa, including the diurnal Propithecus, possessed a tapetum lucidum, a feature only found among nocturnal and crepuscular mammals.

  2. Adrenal-dependent diurnal modulation of conditioned fear extinction learning

    PubMed Central

    Woodruff, Elizabeth R.; Greenwood, Benjamin N.; Chun, Lauren E.; Fardi, Sara; Hinds, Laura R.; Spencer, Robert L.

    2015-01-01

    Post Traumatic Stress Disorder (PTSD) is associated with altered conditioned fear extinction expression and impaired circadian function including dysregulation of glucocorticoid hormone secretion. We examined in adult male rats the relationship between conditioned fear extinction learning, circadian phase, and endogenous glucocorticoids (CORT). Rats maintained on a 12 hr light:dark cycle were trained and tested across 3 separate daily sessions (conditioned fear acquisition and 2 extinction sessions) that were administered during either the rats’ active or inactive circadian phase. In an initial experiment we found that rats at both circadian phases acquired and extinguished auditory cue conditioned fear to a similar degree in the first extinction session. However, rats trained and tested at zeitgeber time-16 (ZT16) (active phase) showed enhanced extinction memory expression during the second extinction session compared to rats trained and tested at ZT4 (inactive phase). In a follow-up experiment, adrenalectomized (ADX) or sham surgery rats were similarly trained and tested across 3 separate daily sessions at either ZT4 or ZT16. ADX had no effect on conditioned fear acquisition or conditioned fear memory. Sham ADX rats trained and tested at ZT16 exhibited better extinction learning across the two extinction sessions compared to all other groups of rats. These results indicate that conditioned fear extinction learning is modulated by time of day, and this diurnal modulation requires the presence of adrenal hormones. These results support an important role of CORT-dependent circadian processes in regulating conditioned fear extinction learning, which may be capitalized upon to optimize effective treatment of PTSD. PMID:25746455

  3. The association between diurnal temperature range and childhood bacillary dysentery

    NASA Astrophysics Data System (ADS)

    Wen, Li-ying; Zhao, Ke-fu; Cheng, Jian; Wang, Xu; Yang, Hui-hui; Li, Ke-sheng; Xu, Zhi-wei; Su, Hong

    2016-02-01

    Previous studies have found that mean, maximum, and minimum temperatures were associated with bacillary dysentery (BD). However, little is known about whether the within-day variation of temperature has any impact on bacillary dysentery. The current study aimed to identify the relationship between diurnal temperature range (DTR) and BD in Hefei, China. Daily data on BD counts among children aged 0-14 years from 1 January 2006 to 31 December 2012 were retrieved from Hefei Center for Disease Control and Prevention. Daily data on ambient temperature and relative humidity covering the same period were collected from the Hefei Bureau of Meteorology. A Poisson generalized linear regression model combined with a distributed lag non-linear model (DLNM) was used in the analysis after controlling the effects of season, long-term trends, mean temperature, and relative humidity. The results showed that there existed a statistically significant relationship between DTR and childhood BD. The DTR effect on childhood bacillary dysentery increased when DTR was over 8 °C. And it was greatest at 1-day lag, with an 8 % (95 % CI = 2.9-13.4 %) increase of BD cases per 5 °C increment of DTR. Male children and children aged 0-5 years appeared to be more vulnerable to the DTR effect. The data indicate that large DTR may increase the incidence of childhood BD. Caregivers and health practitioners should be made aware of the potential threat posed by large DTR. Therefore, DTR should be taken into consideration when making targeted health policies and programs to protect children from being harmed by climate impacts.

  4. The association between diurnal temperature range and childhood bacillary dysentery.

    PubMed

    Wen, Li-ying; Zhao, Ke-fu; Cheng, Jian; Wang, Xu; Yang, Hui-hui; Li, Ke-sheng; Xu, Zhi-wei; Su, Hong

    2016-02-01

    Previous studies have found that mean, maximum, and minimum temperatures were associated with bacillary dysentery (BD). However, little is known about whether the within-day variation of temperature has any impact on bacillary dysentery. The current study aimed to identify the relationship between diurnal temperature range (DTR) and BD in Hefei, China. Daily data on BD counts among children aged 0-14 years from 1 January 2006 to 31 December 2012 were retrieved from Hefei Center for Disease Control and Prevention. Daily data on ambient temperature and relative humidity covering the same period were collected from the Hefei Bureau of Meteorology. A Poisson generalized linear regression model combined with a distributed lag non-linear model (DLNM) was used in the analysis after controlling the effects of season, long-term trends, mean temperature, and relative humidity. The results showed that there existed a statistically significant relationship between DTR and childhood BD. The DTR effect on childhood bacillary dysentery increased when DTR was over 8 °C. And it was greatest at 1-day lag, with an 8% (95% CI = 2.9-13.4%) increase of BD cases per 5 °C increment of DTR. Male children and children aged 0-5 years appeared to be more vulnerable to the DTR effect. The data indicate that large DTR may increase the incidence of childhood BD. Caregivers and health practitioners should be made aware of the potential threat posed by large DTR. Therefore, DTR should be taken into consideration when making targeted health policies and programs to protect children from being harmed by climate impacts.

  5. Diurnal Spectral Sensitivity of the Acute Alerting Effects of Light

    PubMed Central

    Rahman, Shadab A.; Flynn-Evans, Erin E.; Aeschbach, Daniel; Brainard, George C.; Czeisler, Charles A.; Lockley, Steven W.

    2014-01-01

    Study Objectives: Previous studies have demonstrated short-wavelength sensitivity for the acute alerting response to nocturnal light exposure. We assessed daytime spectral sensitivity in alertness, performance, and waking electroencephalogram (EEG). Design: Between-subjects (n = 8 per group). Setting: Inpatient intensive physiologic monitoring unit. Participants: Sixteen healthy young adults (mean age ± standard deviation = 23.8 ± 2.7 y). Interventions: Equal photon density exposure (2.8 × 1013 photons/cm2/s) to monochromatic 460 nm (blue) or 555 nm (green) light for 6.5 h centered in the middle of the 16-h episode of wakefulness during the biological day. Results were compared retrospectively to 16 individuals who were administered the same light exposure during the night. Measurements and Results: Daytime and nighttime 460-nm light exposure significantly improved auditory reaction time (P < 0.01 and P < 0.05, respectively) and reduced attentional lapses (P < 0.05), and improved EEG correlates of alertness compared to 555-nm exposure. Whereas subjective sleepiness ratings did not differ between the two spectral conditions during the daytime (P > 0.05), 460-nm light exposure at night significantly reduced subjective sleepiness compared to 555-nm light exposure at night (P < 0.05). Moreover, nighttime 460-nm exposure improved alertness to near-daytime levels. Conclusions: The alerting effects of short-wavelength 460-nm light are mediated by counteracting both the circadian drive for sleepiness and homeostatic sleep pressure at night, but only via reducing the effects of homeostatic sleep pressure during the day. Citation: Rahman SA; Flynn-Evans EE; Aeschbach D; Brainard GC; Czeisler CA; Lockley SW. Diurnal spectral sensitivity of the acute alerting effects of light. SLEEP 2014;37(2):271-281. PMID:24501435

  6. Adrenal-dependent diurnal modulation of conditioned fear extinction learning.

    PubMed

    Woodruff, Elizabeth R; Greenwood, Benjamin N; Chun, Lauren E; Fardi, Sara; Hinds, Laura R; Spencer, Robert L

    2015-06-01

    Post traumatic stress disorder (PTSD) is associated with altered conditioned fear extinction expression and impaired circadian function including dysregulation of glucocorticoid hormone secretion. We examined in adult male rats the relationship between conditioned fear extinction learning, circadian phase, and endogenous glucocorticoids (CORT). Rats maintained on a 12h light:dark cycle were trained and tested across 3 separate daily sessions (conditioned fear acquisition and 2 extinction sessions) that were administered during either the rats' active or inactive circadian phase. In an initial experiment we found that rats at both circadian phases acquired and extinguished auditory cue conditioned fear to a similar degree in the first extinction session. However, rats trained and tested at zeitgeber time-16 (ZT16) (active phase) showed enhanced extinction memory expression during the second extinction session compared to rats trained and tested at ZT4 (inactive phase). In a follow-up experiment, adrenalectomized (ADX) or sham surgery rats were similarly trained and tested across 3 separate daily sessions at either ZT4 or ZT16. ADX had no effect on conditioned fear acquisition or conditioned fear memory. Sham ADX rats trained and tested at ZT16 exhibited better extinction learning across the two extinction sessions compared to all other groups of rats. These results indicate that conditioned fear extinction learning is modulated by time of day, and this diurnal modulation requires the presence of adrenal hormones. These results support an important role of CORT-dependent circadian processes in regulating conditioned fear extinction learning, which may be capitalized upon to optimize effective treatment of PTSD.

  7. Diurnal Rhythms of Bone Turnover Markers in Three Ethnic Groups

    PubMed Central

    Redmond, Jean; Fulford, Anthony J.; Jarjou, Landing; Zhou, Bo; Prentice, Ann

    2016-01-01

    Context: Ethnic groups differ in fragility fracture risk and bone metabolism. Differences in diurnal rhythms (DRs) of bone turnover and PTH may play a role. Objective: We investigated the DRs of plasma bone turnover markers (BTMs), PTH, and 1,25(OH)2D in three groups with pronounced differences in bone metabolism and plasma PTH. Participants: Healthy Gambian, Chinese, and white British adults (ages 60–75 years; 30 per country). Interventions: Observational study with sample collection every 4 hours for 24 hours. Main Outcomes: Levels of plasma C-terminal telopeptide of type I collagen, procollagen type-1 N-propeptide, N-mid osteocalcin, bone alkaline phosphatase, PTH, and 1,25-dihydroxyvitamin D were measured. DRs were analyzed with random-effects Fourier regression and cross-correlation and regression analyses to assess associations between DRs and fasting and 24-hour means of BTMs and PTH. Results: Concentrations of BTMs, PTH, and 1,25-dihydroxyvitamin D were higher in Gambians compared to other groups (P < .05). The DRs were significant for all variables and groups (P < .03) and were unimodal, with a nocturnal peak and a daytime nadir for BTMs, whereas PTH had two peaks. The DRs of BTMs and PTH were significantly cross-correlated for all groups (P < .05). There was a significant positive association between C-terminal telopeptide of type I collagen and PTH in the British and Gambian groups (P = .03), but not the Chinese group. Conclusions: Despite ethnic differences in plasma BTMs and PTH, DRs were similar. This indicates that alteration of rhythmicity and loss of coupling of bone resorption and formation associated with an elevated PTH in other studies may not uniformly occur across different populations and needs to be considered in the interpretation of PTH as a risk factor of increased bone loss. PMID:27294326

  8. Global and Regional Diurnal Variations of Organized Convection.

    NASA Astrophysics Data System (ADS)

    Tsakraklides, Giorgos; Evans, Jenni L.

    2003-05-01

    An automated objective classification procedure, the Convection Classification and Automated Tracking System (CCATS), is used to analyze the mean life cycles of organized convection in the global Tropics and midlatitudes (40°N-40°S). Five years (1989-93) of infrared satellite imagery are examined for the Pacific and Atlantic basins and one year (April 1988-March 1989) is studied for the Indian basin.Two main classes of organized convection (lifetime of 6 h or more) are tracked: MCT and CCC. MCT represent a combined dataset of tropical cyclones and mesoscale convective complexes (MCC). Convective cloud clusters (CCC) meet the same cold cloud-top temperature, time, and size criteria used to distinguish MCC, but fail to sustain the same high degree of symmetry for at least 6 h. That is, CCC represent more elongated systems, such as squall lines. The frequency of CCC exceeds that of MCT by a factor of 30 over both land and sea.MCT and CCC are each stratified to into 12 continental and oceanic regions and the diurnal variation of system characteristics in each geographic region are studied, leading to composite life cycle descriptions for each region. Oceanic CCC formed overnight and the shorter-lived, land-based CCC formed in the afternoon; apart from this time offset, oceanic and land-based CCC were found to have very similar life cycle evolution patterns.Continental MCT exhibit a rapid size expansion early; this is not part of the oceanic system life cycle. Apart from this growth spurt, the evolution of land and ocean MCT follows the same pattern of CCC with early symmetry, then size expansion until just before termination. Land-based MCT are longer lived and more symmetric than oceanic MCT.

  9. Diurnal variation in the quantitative EEG in healthy adult volunteers

    PubMed Central

    Cummings, L; Dane, A; Rhodes, J; Lynch, P; Hughes, A M

    2000-01-01

    Aims To define the change in power in standard waveband frequencies of quantitative cortical electroencephalogram (EEG) data over a 24 h period, in a drug free representative healthy volunteer population. Methods This was an open, non randomised study in which 18 volunteers (9 male and 9 female) were studied on 1 study day, over a 24 h period. Volunteers had a cortical EEG recording taken at 0, 2, 4, 6, 8, 10, 12, 16 and 24 h. Each recording lasted for 6 min (3 min eyes open, 3 min eyes closed). All EEG recordings were taken in a quietened ward environment with the curtains drawn round the bed and the volunteer supine. During the 3 min eyes open, volunteers were asked to look at a red circle on a screen at the foot of the bed, and refrain from talking. Results Plots produced of geometric mean power by time of the standard wave band frequencies gave some indication of a circadian rhythm over the 24 h period for θ (4.75–6.75 Hz), α1 (7.0–9.5 Hz) and β1 (12.75–18.50 Hz) wavebands. Mixed models were fitted to both the eyes open and eyes closed data which confirmed a change in mean waveband power with time with statistical significance at the conventional 5% level (P < 0.05). Conclusions These data indicate the presence of a diurnal variation in the cortical quantitative EEG. They support the use of a placebo control group when designing clinical trials which utilize quantitative EEG to screen for central nervous system (CNS) activity of pharmaceutical agents, to control for the confounding variable of time of day at which the EEG recordings were made. PMID:10886113

  10. Diurnal Cycle of Convective Cloud Systems over the Maritime Continent and Its Variability During MJO

    NASA Astrophysics Data System (ADS)

    Chen, S. S.

    2015-12-01

    It has been well documented that the diurnal maximum of convection and precipitation is observed during the morning hours (AM) over the ocean, whereas the maximum is during the afternoon hours (PM) over land. However, the difference between AM and PM precipitation in the coastal/adjacent seas over the Maritime Continent (MC) is 2-3 times larger than anywhere else in the tropics. Most large mesoscale convective systems (MCSs) during the local active phases of the MJO are over water of the MC. This makes the convective signals of the Madden-Julian Oscillation (MJO) much larger over the water than over the islands when the MJO moves through the MC. In this study, we examine the diurnal cycle of formation, propagation, and dissipation of MCSs by tracking cloud clusters in time and space using hourly satellite IR data and 3-hourly TRMM data. It is found that the large AM precipitation over the adjacent seas is a result of the propagating MCSs from the islands to the sea during the night, which are forced by the enhanced land breeze from the high mountains of the islands in the MC. MCSs can also initiate over the seas during the diurnal maximum of SST in the afternoon and continue to grow into the night and maximize during the early morning. The diurnal cycle of convection is modulated by the MJO. The two factors together may explain the large diurnal amplitude over the adjacent seas of the MC than that of the open ocean. The complex interactions of the convection, local and large-scale circulation, and the unique land-sea geography of the MC are further investigated using a high-resolution, coupled atmosphere-ocean model. The result indicates that the diurnal cycle of SST is affected by the tidal mixing in the ocean, which may be an important factor contributing to the air-sea interaction on the diurnal and MJO time scales.

  11. Impact of model resolution on the simulation of diurnal variations of precipitation over East Asia

    NASA Astrophysics Data System (ADS)

    Jin, Emilia Kyung; Choi, In-Jin; Kim, So-Young; Han, Ji-Young

    2016-02-01

    The impact of model resolution on the simulation of diurnal variations of precipitation over East Asia during the summer monsoon period of 2006 is investigated by conducting a suite of ensemble simulations of three different cumulus parameterization schemes (CPS), which are Kain-Fritsch, Kain-Fritsch with a modified trigger function, and Simplified Arakawa-Schubert, and the convection-permitting (CP) setting with the Weather Research and Forecasting model. The horizontal resolutions of 50 km, 27 km, and 9 km are applied for each different representation of convection process. Model simulations as a whole are able to mimic the diurnal and semidiurnal cycles with 24 h and 12 h peaks in the morning and the afternoon. However, the simulated afternoon peaks over land are earlier in the CPS runs, while delayed in the CP runs, compared to those observed. The increase of resolution improves the phase and amplitude of diurnal variations in the CP runs due to the explicit representation of the realistic cloud system. In addition, the contribution of nonconvective precipitation from the microphysical process significantly improves the phase of diurnal variations in the CPS runs, especially the afternoon peak over land. The KFtr scheme outperforms other schemes in reproducing the diurnal variations due to the relatively dominant role of nonconvective precipitation. Phase does not change with increasing resolution in the diurnal variations of convective precipitation. Only the modification of the convection scheme, such as the alternative trigger function in the KFtr scheme distinguished from the KF scheme, can make fundamental changes in phase of diurnal variation.

  12. Sensitivity of Amazonian TOA flux diurnal cycle composite monthly variability to choice of reanalysis

    PubMed Central

    Taylor, Patrick C.

    2016-01-01

    Abstract Amazonian deep convection experiences a strong diurnal cycle driven by the cycle in surface sensible heat flux, which contributes to a significant diurnal cycle in the top of the atmosphere (TOA) radiative flux. Even when accounting for seasonal variability, the TOA flux diurnal cycle varies significantly on the monthly timescale. Previous work shows evidence supporting a connection between variability in the convective and radiative cycles, likely modulated by variability in monthly atmospheric state (e.g., convective instability). The hypothesized relationships are further investigated with regression analysis of the radiative diurnal cycle and atmospheric state using additional meteorological variables representing convective instability and upper tropospheric humidity. The results are recalculated with three different reanalyses to test the reliability of the results. The radiative diurnal cycle sensitivity to upper tropospheric humidity is about equal in magnitude to that of convective instability. In addition, the results are recalculated with the data subdivided into the wet and dry seasons. Overall, clear‐sky radiative effects have a dominant role in radiative diurnal cycle variability during the dry season. Because of this, even in a convectively active region, the clear‐sky radiative effects must be accounted for in order to fully explain the monthly variability in diurnal cycle. Finally, while there is general agreement between the different reanalysis‐based results when examining the full data time domain (without regard to time of year), there are significant disagreements when the data are divided into wet and dry seasons. The questionable reliability of reanalysis data is a major limitation. PMID:27840782

  13. Mechanisms for Diurnal Variability of Global Tropical Rainfall Observed from TRMM

    NASA Technical Reports Server (NTRS)

    Yang, Song; Smith, Eric A.

    2004-01-01

    The behavior and various controls of diurnal variability in tropical-subtropical rainfall are investigated using Tropical Rainfall Measuring Mission (TRMM) precipitation measurements retrieved from: (1) TRMM Microwave Imager (TMI), (2) Precipitation Radar (PR), and (3) TMI/PR Combined, standard level 2 algorithms for the 1998 annual cycle. Results show that the diurnal variability characteristics of precipitation are consistent for all three algorithms, providing assurance that TRMM retrievals are providing consistent estimates of rainfall variability. As anticipated, most ocean areas exhibit more rainfall at night, while over most land areas rainfall peaks during daytime ,however, various important exceptions are found. The dominant feature of the oceanic diurnal cycle is a rainfall maximum in late-evening/early-morning (LE-EM) hours, while over land the dominant maximum occurs in the mid- to late-afternoon (MLA). In conjunction with these maxima are pronounced seasonal variations of the diurnal amplitudes. Amplitude analysis shows that the diurnal pattern and its seasonal evolution are closely related to the rainfall accumulation pattern and its seasonal evolution. In addition, the horizontal distribution of diurnal variability indicates that for oceanic rainfall there is a secondary MLA maximum, co-existing with the LE-EM maximum, at latitudes dominated by large scale convergence and deep convection. Analogously, there is a preponderance for an LE-EM maximum over land, co-existing with the stronger MLA maximum, although it is not evident that this secondary continental feature is closely associated with the large scale circulation. The ocean results clearly indicate that rainfall diurnal variability associated with large scale convection is an integral part of the atmospheric general circulation.

  14. Changes in diurnal temperature range and national cereal yields

    SciTech Connect

    Lobell, D

    2007-04-26

    Models of yield responses to temperature change have often considered only changes in average temperature (Tavg), with the implicit assumption that changes in the diurnal temperature range (DTR) can safely be ignored. The goal of this study was to evaluate this assumption using a combination of historical datasets and climate model projections. Data on national crop yields for 1961-2002 in the 10 leading producers of wheat, rice, and maize were combined with datasets on climate and crop locations to evaluate the empirical relationships between Tavg, DTR, and crop yields. In several rice and maize growing regions, including the two major nations for each crop, there was a clear negative response of yields to increased DTR. This finding reflects a nonlinear response of yields to temperature, which likely results from greater water and heat stress during hot days. In many other cases, the effects of DTR were not statistically significant, in part because correlations of DTR with other climate variables and the relatively short length of the time series resulted in wide confidence intervals for the estimates. To evaluate whether future changes in DTR are relevant to crop impact assessments, yield responses to projected changes in Tavg and DTR by 2046-2065 from 11 climate models were estimated. The mean climate model projections indicated an increase in DTR in most seasons and locations where wheat is grown, mixed projections for maize, and a general decrease in DTR for rice. These mean projections were associated with wide ranges that included zero in nearly all cases. The estimated impacts of DTR changes on yields were generally small (<5% change in yields) relative to the consistently negative impact of projected warming of Tavg. However, DTR changes did significantly affect yield responses in several cases, such as in reducing US maize yields and increasing India rice yields. Because DTR projections tend to be positively correlated with Tavg, estimates of yields

  15. Initial full-diurnal-cycle mesopause region lidar observations: diurnal-means and tidal perturbations of temperature and winds over Fort Collins, CO (41°N,105°W)

    NASA Astrophysics Data System (ADS)

    She, Chiao-Yao

    2004-04-01

    The Colorado State Sodium lidar has been upgraded to a two-beam system capable of simultaneous measurements of mesopause region temperature and winds, over full diurnal-cycles, weather permitting. Though our lidar is a modest system with a power-aperture product of only 0.06Wm2, good data quality is demonstrated by means of contour plots depicting a 80-h continuous observation between August 9th and 12th, showing the existence of atmospheric waves with different periods along with their coherence and interactions. The salient feature of data with full-diurnal-cycle coverage lies in its ability to describe the vertical profiles of dynamical fields (temperature, zonal and meridional winds) as a unique linear superposition of diurnal-mean and oscillations with different tidal periods, plus a residual term. In this manner, we investigate diurnal-means and oscillations with diurnal and semidiurnal periods. Using 6 data sets between July 17 and August 12, each covering a full-diurnal-cycle as a case study, we found considerable day-to-day variability, as much as 20K, 35 and 75m/s for diurnal-mean temperature, zonal wind and meridional wind, respectively, and as 15K, and 50m/s, for the diurnal and semidiurnal tidal temperature and wind amplitudes, respectively. While a minimum of 3 full diurnal cycles appears to be adequate in the case studied here, the 6-day composite yields diurnal-means and diurnal tides in agreement with model predictions very well. Since the resulting amplitudes and phases of the observed diurnal oscillations agree well with the global scale wave model, GSWM00 predictions, we conclude that the migrating diurnal tide contributes significantly to the observed oscillations with diurnal period over Fort Collins, CO (41°N, 105°W). Unlike the diurnal perturbations, the observed semidiurnal amplitudes and phases differ from the GSWM00 predictions with considerably smaller model amplitudes. The coherence of solar forcing is found to prevail over the

  16. Transcriptome phase distribution analysis reveals diurnal regulated biological processes and key pathways in rice flag leaves and seedling leaves.

    PubMed

    Xu, Wenying; Yang, Rendong; Li, Meina; Xing, Zhuo; Yang, Wenqiang; Chen, Guang; Guo, Han; Gong, Xiaojie; Du, Zhou; Zhang, Zhenhai; Hu, Xingming; Wang, Dong; Qian, Qian; Wang, Tai; Su, Zhen; Xue, Yongbiao

    2011-03-02

    Plant diurnal oscillation is a 24-hour period based variation. The correlation between diurnal genes and biological pathways was widely revealed by microarray analysis in different species. Rice (Oryza sativa) is the major food staple for about half of the world's population. The rice flag leaf is essential in providing photosynthates to the grain filling. However, there is still no comprehensive view about the diurnal transcriptome for rice leaves. In this study, we applied rice microarray to monitor the rhythmically expressed genes in rice seedling and flag leaves. We developed a new computational analysis approach and identified 6,266 (10.96%) diurnal probe sets in seedling leaves, 13,773 (24.08%) diurnal probe sets in flag leaves. About 65% of overall transcription factors were identified as flag leaf preferred. In seedling leaves, the peak of phase distribution was from 2:00am to 4:00am, whereas in flag leaves, the peak was from 8:00pm to 2:00am. The diurnal phase distribution analysis of gene ontology (GO) and cis-element enrichment indicated that, some important processes were waken by the light, such as photosynthesis and abiotic stimulus, while some genes related to the nuclear and ribosome involved processes were active mostly during the switch time of light to dark. The starch and sucrose metabolism pathway genes also showed diurnal phase. We conducted comparison analysis between Arabidopsis and rice leaf transcriptome throughout the diurnal cycle. In summary, our analysis approach is feasible for relatively unbiased identification of diurnal transcripts, efficiently detecting some special periodic patterns with non-sinusoidal periodic patterns. Compared to the rice flag leaves, the gene transcription levels of seedling leaves were relatively limited to the diurnal rhythm. Our comprehensive microarray analysis of seedling and flag leaves of rice provided an overview of the rice diurnal transcriptome and indicated some diurnal regulated biological

  17. Numerical Modelling of the Observed Diurnal Cycle of Indian Monsoon Rainfall

    NASA Astrophysics Data System (ADS)

    Sahany, S.; Vuruputur, V.; Nanjundiah, R. S.

    2009-12-01

    We have analysed the diurnal cycle of rainfall over the Indian region (10S-35N, 60E-100E) using both satellite and in-situ data, and found many interesting features associated with this fundamental, yet under-explored, mode of variability. Since there is a distinct and strong diurnal mode of variability associated with the Indian summer monsoon rainfall, we evaluate the ability of the Weather Research and Forecasting Model (WRF) to simulate the observed diurnal rainfall characteristics. The model (at 54km grid-spacing) is integrated for the month of July, 2006, since this period was particularly favourable for the study of diurnal cycle. We first evaluate the sensitivity of the model to the prescribed sea surface temperature (SST), by using two different SST datasets, namely, Final Analyses (FNL) and Real-time Global (RTG). It was found that with RTG SST the rainfall simulation over central India (CI) was significantly better than that with FNL. On the other hand, over the Bay of Bengal (BoB), rainfall simulated with FNL was marginally better than with RTG. However, the overall performance of RTG SST was found to be better than FNL, and hence it was used for further model simulations. Next, we investigated the role of the convective parameterization scheme on the simulation of diurnal cycle of rainfall. We found that the Kain-Fritsch (KF) scheme performs significantly better than Betts-Miller-Janjić (BMJ) and Grell-Devenyi schemes. We also studied the impact of other physical parameterizations, namely, microphysics, boundary layer, land surface, and the radiation parameterization, on the simulation of diurnal cycle of rainfall, and identified the “best” model configuration. We used this configuration of the “best” model to perform a sensitivity study on the role of various convective components used in the KF scheme. In particular, we studied the role of convective downdrafts, convective timescale, and feedback fraction, on the simulated diurnal cycle of

  18. On the Sensitivity of the Diurnal Cycle in the Amazon to Convective Intensity

    NASA Astrophysics Data System (ADS)

    Itterly, K. F.; Taylor, P. C.

    2015-12-01

    The sensitivity of the diurnal cycle to convective intensity is investigated for the wet season (DJF) and dry season (JJA) in the Amazon region. Model output reveals large water and energy budget errors in tropical rainforests, arising from a misrepresentation of the diurnal cycle of the complex processes inherent to diurnally forced moist convection. Daily, 3-hourly satellite observations of CERES Ed3a SYN1DEG TOA fluxes and 3-hourly TRMM 3B42 precipitation rate from 2002-2012 are split into regimes of convective intensity using percentile definitions for both daily minimum OLR and daily maximum precipitation rate to define regimes. These satellite-defined regimes are then co-located with convective parameters calculated from radiosonde observations. Diurnal statistics from satellite include: phase, amplitude, precipitation onset, precipitation duration and diurnal mean. The diurnal phase of outgoing longwave radiation (OLR) and longwave cloud forcing (LWCF) occurs several hours earlier on convective days compared to stable days, however, climatological precipitation phase is less sensitive to convective intensity, occurring between 1-4PM local time for all regimes and 1-2 hours later on very convective days, which is related to longer duration precipitation events from increased humidity. Diurnal convection in the Amazon is strongly related to 8AM values of both dynamic and thermodynamic variables, most of which are related to: the background moisture content of the troposphere, the stability of the lower troposphere, convective inhibition (CIN) and wind speed and direction in the column. Morning values of CIN, lifted condensation level (LCL), level of free convection (LFC) and equilibrium level (EL) are lower in DJF than JJA, and lower on very convective days than stable days for all stations. Higher background humidity is related to longer duration precipitation events (r-values between 0.4-0.6, depending on station and season), earlier phases and onset times

  19. Comparison of modeled diurnally varying sea surface temperatures to satellite data

    NASA Astrophysics Data System (ADS)

    Weihs, R. R.; Bourassa, M. A.

    2012-12-01

    A subset of modeled, global diurnally varying sea surface temperatures (SSTs) is created using a physically based, one-dimensional, upper ocean heating model, POSH or Profiles in Oceanic Surface Heating. The model is forced with a nighttime minimum temperature approximated by the Reynolds OI daily AVHRR-only and reanalysis data from NASA's MERRA dataset. To assess the model's ability to replicate the diurnal cycle of SSTs, the model output is compared to satellite-retrieved data for the entire cycle. SEVIRI hourly 5-km SST swath data are used for the comparison and regridded to the 25-km model grid. In the analysis of SST differences between the two products, difference plots at each time step are not sufficient to determine the quality of POSH's representation of the diurnal cycle. The differences in SST can be a combination of a nighttime offset and a shift in the onset of the heating cycle. Furthermore, the caveats associated with gap filling by the interpolation technique can deteriorate the quality of the comparison, especially when the satellite data are not continuous over time. To establish quality criteria, a 2D histogram is computed to determine the percent of coverage per 0.25-degree grid cell. This is a combined measure of the density (how many satellite grid points lie within the 0.25-degree cell) and the continuity (how often, in hours, the grid cell is sampled over the day). In a best-case scenario approach for the comparison, a total of 89 grid locations are selected at which time series of SSTs are extracted from the satellite and model data. The results in Figure 1 indicate that the Reynolds product estimates the nighttime minimum temperature reasonably well, while the model consistently overestimates the peak of the diurnal cycle compared to the satellite data. Moreover, the diurnal heating in the satellite data persists approximately 3 hours longer than the diurnal heating produced by the model. Since the difference averaged over all hours of

  20. Diurnal lighting patterns and habitat alter opsin expression and colour preferences in a killifish

    PubMed Central

    Johnson, Ashley M.; Stanis, Shannon; Fuller, Rebecca C.

    2013-01-01

    Spatial variation in lighting environments frequently leads to population variation in colour patterns, colour preferences and visual systems. Yet lighting conditions also vary diurnally, and many aspects of visual systems and behaviour vary over this time scale. Here, we use the bluefin killifish (Lucania goodei) to compare how diurnal variation and habitat variation (clear versus tannin-stained water) affect opsin expression and the preference to peck at different-coloured objects. Opsin expression was generally lowest at midnight and dawn, and highest at midday and dusk, and this diurnal variation was many times greater than variation between habitats. Pecking preference was affected by both diurnal and habitat variation but did not correlate with opsin expression. Rather, pecking preference matched lighting conditions, with higher preferences for blue at noon and for red at dawn/dusk, when these wavelengths are comparatively scarce. Similarly, blue pecking preference was higher in tannin-stained water where blue wavelengths are reduced. In conclusion, L. goodei exhibits strong diurnal cycles of opsin expression, but these are not tightly correlated with light intensity or colour. Temporally variable pecking preferences probably result from lighting environment rather than from opsin production. These results may have implications for the colour pattern diversity observed in these fish. PMID:23698009

  1. Diurnal Variation in Gravity Wave Activity at Low and Middle Latitudes

    NASA Technical Reports Server (NTRS)

    Andrioli, V. F.; Fritts, D. C.; Batista, P. P.; Clemesha, B. R.; Janches, Diego

    2013-01-01

    We employ a modified composite day extension of the Hocking (2005) analysis method to study gravity wave (GW) activity in the mesosphere and lower thermosphere using 4 meteor radars spanning latitudes from 7deg S to 53.6deg S. Diurnal and semidiurnal modulations were observed in GW variances over all sites. Semidiurnal modulation with downward phase propagation was observed at lower latitudes mainly near the equinoxes. Diurnal modulations occur mainly near solstice and, except for the zonal component at Cariri (7deg S), do not exhibit downward phase propagation. At a higher latitude (SAAMER, 53.6deg S) these modulations are only observed in the meridional component where we can observe diurnal variation from March to May, and semidiurnal, during January, February, October (above 88 km) and November. Some of these modulations with downward phase progression correlate well with wind shear. When the wind shear is well correlated with the maximum of the variances the diurnal tide has its largest amplitudes, i.e., near equinox. Correlations exhibiting variations with tidal phases suggest significant GW-tidal interactions that have different characters depending on the tidal components and possible mean wind shears. Modulations that do not exhibit phase variations could be indicative of diurnal variations in GW sources.

  2. The contributions of sleep-related risk factors to diurnal car accidents.

    PubMed

    Lucidi, Fabio; Mallia, Luca; Violani, Cristiano; Giustiniani, Gabriele; Persia, Luca

    2013-03-01

    This study was intended to estimate the presence and number of individual sleep-related risk factors in a sample of diurnal car accidents and to analyze the extent to which these risk factors tended to be more represented in diurnal accidents involving only one vehicle, involving young drivers or occurring on non-urban roads. Two hundred fifty-three drivers involved in diurnal accidents were interviewed immediately after the accidents to assess their sleepiness-related personal conditions and the circumstances prior to the accident (i.e., individual sleep-related risk factors), such as poor sleep, changes in habitual sleeping patterns, prolonged wakefulness, self-reported acute sleepiness and daytime sleepiness, night-shift jobs and insomnia. A total of 12.3% of the drivers were classified as having at least one of the seven risk factors assessed in the study, supporting the general notion that drivers' sleepiness conditions are crucial, even in diurnal driving circumstances in which they are less likely to depend on chrono-biological processes. Furthermore, consistent with the guiding hypotheses, specific sleep-related risk factors were more evident in single (vs. multiple) car accidents, among young drivers and in car accidents occurring on non-urban roads. In summary, sleep-related risk factors seemed to have a negative impact on drivers' safety in circumstances of diurnal driving, especially when the accidents involved young individuals and occurred on non-urban roads.

  3. The Met Office's new operational analysis system for diurnally varying skin-SST

    NASA Astrophysics Data System (ADS)

    While, James; Mao, Chongyuan; Martin, Matthew; Good, Simon; Sykes, Peter

    2016-04-01

    Diurnal variations in skin Sea Surface Temperature (skin SST), which can be as large as several degrees, play an important role in determining the heat flux between the ocean and atmosphere. As such, since February 2015 the Met Office, as part of the Copernicus Marine Environment Monitoring Service (CMEMS), has been producing an operational analysis of the diurnal cycle of skin SST. This product consists of three components: an underlying 'foundation' SST (based on the OSTIA analysis), a warm layer where solar heating is important, and a cool skin where cooling due to long wave radiation dominates. A major development in this system is the use of a 4D-Var data assimilation technique with multiple outer-loops to improve estimates of the warm layer. Observations assimilated come from the SEVIRI, GOES-W, MTSAT2, and NOAA-AVHRR infra-red satellite instruments. Through their assimilation, the observations act to update the applied heat and wind flux such that the diurnal cycle in the warm layer is improved. In this presentation we describe the analysis system and how it produces a skin SST product. Particular attention is paid to the data assimilation aspects and on the observation processing. We also present results from a three month validation period showing that the system is well able to reproduce a drifter based climatology of the diurnal cycle in SST. A direct validation of our diurnal SST output against near surface Argo data is also given.

  4. Diurnal lighting patterns and habitat alter opsin expression and colour preferences in a killifish.

    PubMed

    Johnson, Ashley M; Stanis, Shannon; Fuller, Rebecca C

    2013-07-22

    Spatial variation in lighting environments frequently leads to population variation in colour patterns, colour preferences and visual systems. Yet lighting conditions also vary diurnally, and many aspects of visual systems and behaviour vary over this time scale. Here, we use the bluefin killifish (Lucania goodei) to compare how diurnal variation and habitat variation (clear versus tannin-stained water) affect opsin expression and the preference to peck at different-coloured objects. Opsin expression was generally lowest at midnight and dawn, and highest at midday and dusk, and this diurnal variation was many times greater than variation between habitats. Pecking preference was affected by both diurnal and habitat variation but did not correlate with opsin expression. Rather, pecking preference matched lighting conditions, with higher preferences for blue at noon and for red at dawn/dusk, when these wavelengths are comparatively scarce. Similarly, blue pecking preference was higher in tannin-stained water where blue wavelengths are reduced. In conclusion, L. goodei exhibits strong diurnal cycles of opsin expression, but these are not tightly correlated with light intensity or colour. Temporally variable pecking preferences probably result from lighting environment rather than from opsin production. These results may have implications for the colour pattern diversity observed in these fish.

  5. Regimes of Diurnal Variation of Summer Rainfall over Subtropical East Asia

    SciTech Connect

    Yuan W.; Lin W.; Yu, R.; Zhang, M.; Chen, H.; Li, J.

    2012-05-01

    Using hourly rain gauge records and Tropical Rainfall Measuring Mission 3B42 from 1998 to 2006, the authors present an analysis of the diurnal characteristics of summer rainfall over subtropical East Asia. The study shows that there are four different regimes of distinct diurnal variation of rainfall in both the rain gauge and the satellite data. They are located over the Tibetan Plateau with late-afternoon and midnight peaks, in the western China plain with midnight to early-morning peaks, in the eastern China plain with double peaks in late afternoon and early morning, and over the East China Sea with an early-morning peak. No propagation of diurnal phases is found from the land to the ocean across the coastlines. The different diurnal regimes are highly correlated with the inhomogeneous underlying surface, such as the plateau, plain, and ocean, with physical mechanisms consistent with the large-scale 'mountain-valley' and 'land-sea' breezes and convective instability. These diurnal characteristics over subtropical East Asia can be used as diagnostic metrics to evaluate the physical parameterization and hydrological cycle of climate models over East Asia.

  6. Hydraulic dispersion of diurnal reactive constituents in an open channel eutrophic flow

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Chen, G. Q.

    2016-06-01

    Closely related to the solar photocycle, plankton growth in eutrophic waters displays a diurnal variation because of photosynthesis and respiration. Presented in this paper is an analytical study of the diurnal variation of mean concentration of plankton and nutrient in an open channel eutrophic flow initiated by an instantaneous emission. The evolution of the concentration is shown driven by the combination of hydraulic dispersion and diurnal reaction between plankton and nutrient. The analytical solution for longitudinal distribution of concentration is rigorously derived and illustrated, based on the time dependent hydraulic dispersivity. Numerical results are presented and characterized by the reaction rate, yield factor and period for the diurnal reaction and the P e ´ clet number of the flow. For typical applications such as ecological risk assessment and environmental impact assessment, the upper and lower limits of critical length and duration of five typical pollutant concentrations are concretely illustrated for given concentration criterions. Remarkable diurnal variations are revealed up to around one third in the critical length and duration for plankton, and about ten percent for nutrient.

  7. Long-term Reliability of Diurnal Intraocular Pressure Patterns in Healthy Asians

    PubMed Central

    Chun, Yeoun Sook; Park, In Ki; Shin, Ko Un

    2017-01-01

    Purpose To determine the long-term repeatability of diurnal intraocular pressure (IOP) patterns in healthy Asian subjects without glaucoma. Methods Twenty-three eyes in 23 healthy Asian subjects without glaucoma underwent diurnal IOP measurements using Goldmann applanation tonometry every 2 hours from 9 AM to 11 PM during two visits that were 8 weeks apart. To validate repeatability between visits, we calculated intra-class correlation coefficients (ICCs) mean IOP, peak IOP, minimum IOP, and IOP fluctuation at each time point and expressed the results as the difference between peak IOP and minimum IOP or as the standard deviation of all diurnal IOP values in the diurnal IOP curve. Results IOP repeatability was excellent at all time points, with ICCs ranging from 0.812 to 0.946 (p < 0.001). The 9 AM IOP showed the best repeatability between visits (ICCs, 0.946). Repeatability of mean IOP, peak IOP, and minimum IOP was also excellent (ICCs ranging from 0.899 to 0.929). However, IOP fluctuations showed poor repeatability, with an ICC lower than 0.15. Conclusions Long-term repeatability of diurnal IOP patterns in healthy Asian subjects was excellent. These findings suggest that IOP measurements at standardized times of the day will be useful for assessing the effectiveness of glaucoma therapy. PMID:28367041

  8. Impact of diurnal atmosphere-ocean coupling on tropical climate simulations using a coupled GCM

    NASA Astrophysics Data System (ADS)

    Ham, Yoo-Geun; Kug, Jong-Seong; Kang, In-Sik; Jin, Fei-Fei; Timmermann, Axel

    2009-05-01

    The impacts of diurnal atmosphere-ocean (air-sea) coupling on tropical climate simulations are investigated using the SNU coupled GCM. To investigate the effect of the atmospheric and oceanic diurnal cycles on a climate simulation, a 1-day air-sea coupling interval experiment is compared to a 2-h coupling experiment. As previous studies have suggested, cold temperature biases over equatorial western Pacific regions are significantly reduced when diurnal air-sea coupling strategy is implemented. This warming is initiated by diurnal rectification and amplified further by the air-sea coupled feedbacks. In addition to its effect on the mean climatology, the diurnal coupling has also a distinctive impact on the amplitude of the El Nino-Southern Oscillation (ENSO). It is demonstrated that a weakening of the ENSO magnitude is caused by reduced (increased) surface net heat fluxes into the ocean during El Nino (La Nina) events. Primarily, decreased (increased) incoming shortwave radiation during El Nino (La Nina) due to cloud shading is responsible for the net heat fluxes associated with ENSO.

  9. Did Adult Diurnal Activity Influence the Evolution of Wing Morphology in Opoptera Butterflies?

    PubMed

    Penz, C M; Heine, K B

    2016-02-01

    The butterfly genus Opoptera includes eight species, three of which have diurnal habits while the others are crepuscular (the usual activity period for members of the tribe Brassolini). Although never measured in the field, it is presumed that diurnal Opoptera species potentially spend more time flying than their crepuscular relatives. If a shift to diurnal habits potentially leads to a higher level of activity and energy expenditure during flight, then selection should operate on increased aerodynamic and energetic efficiency, leading to changes in wing shape. Accordingly, we ask whether diurnal habits have influenced the evolution of wing morphology in Opoptera. Using phylogenetically independent contrasts and Wilcoxon rank sum tests, we confirmed our expectation that the wings of diurnal species have higher aspect ratios (ARs) and lower wing centroids (WCs) than crepuscular congeners. These wing shape characteristics are known to promote energy efficiency during flight. Three Opoptera wing morphotypes established a priori significantly differed in AR and WC values. The crepuscular, cloud forest dweller Opoptera staudingeri (Godman & Salvin) was exceptional in having an extended forewing tip and the highest AR and lowest WC within Opoptera, possibly to facilitate flight in a cooler environment. Our study is the first to investigate how butterfly wing morphology might evolve as a response to a behavioral shift in adult time of activity.

  10. Diurnal and circadian variation of sleep and alertness in men vs. naturally cycling women.

    PubMed

    Boivin, Diane B; Shechter, Ari; Boudreau, Philippe; Begum, Esmot Ara; Ng Ying-Kin, Ng Mien Kwong

    2016-09-27

    This study quantifies sex differences in the diurnal and circadian variation of sleep and waking while controlling for menstrual cycle phase and hormonal contraceptive use. We compared the diurnal and circadian variation of sleep and alertness of 8 women studied during two phases of the menstrual cycle and 3 women studied during their midfollicular phase with that of 15 men. Participants underwent an ultradian sleep-wake cycle (USW) procedure consisting of 36 cycles of 60-min wake episodes alternating with 60-min nap opportunities. Core body temperature (CBT), salivary melatonin, subjective alertness, and polysomnographically recorded sleep were measured throughout this procedure. All analyzed measures showed a significant diurnal and circadian variation throughout the USW procedure. Compared with men, women demonstrated a significant phase advance of the CBT but not melatonin rhythms, as well as an advance in the diurnal and circadian variation of sleep measures and subjective alertness. Furthermore, women experienced an increased amplitude of the diurnal and circadian variation of alertness, mainly due to a larger decline in the nocturnal nadir. Our results indicate that women are likely initiating sleep at a later circadian phase than men, which may be one factor contributing to the increased susceptibility to sleep disturbances reported in women. Lower nighttime alertness is also observed, suggesting a physiological basis for a greater susceptibility to maladaptation to night shift work in women.

  11. Monthly covariability of Amazonian convective cloud properties and radiative diurnal cycle

    NASA Astrophysics Data System (ADS)

    Dodson, J. Brant; Taylor, Patrick C.

    2017-02-01

    The diurnal cycle of convective clouds greatly influences the top-of-atmosphere radiative energy balance in convectively active regions of Earth, through both direct presence and the production of anvil and stratiform clouds. CloudSat and CERES data are used to further examine these connections by determining the sensitivity of monthly anomalies in the radiative diurnal cycle to monthly anomalies in multiple cloud variables. During months with positive anomalies in convective frequency, the longwave diurnal cycle is shifted and skewed earlier in the day by the increased longwave cloud forcing during the afternoon from mature deep convective cores and associated anvils. This is consistent with previous studies using reanalysis data to characterize anomalous convective instability. Contrary to this, months with positive anomalies in convective cloud top height (commonly associated with more intense convection) shifts the longwave diurnal cycle later in the day. The contrary results are likely an effect of the inverse relationships between cloud top height and frequency. The albedo diurnal cycle yields inconsistent results when using different cloud variables.

  12. Interpretation of subplanetary-scale diurnal variance in the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Lieberman, R. S.; Riggin, D.

    2004-12-01

    Numerical studies indicate that diurnal waves of intermediate scale (zonal wavenumbers between 4 and 15) are significant momentum sources for the stratopause and mesopause semiannual oscillations. This paper presents observational support for such waves in the middle atmosphere. Day-night differences from the Limb Infrared Monitor of the Stratosphere (LIMS) temperatures are analyzed as proxies for the diurnal tide. The variance in zonal wavenumber 9-16 is weakest in the mesosphere when the underlying zonal mean winds are directed westward in the lower stratosphere, and eastward in the upper stratosphere and lower mesosphere. This behavior is consistent with critical level filtering of diurnal subplanetary scale waves by the zonal mean winds. However, this mechanism cannot be verified without information about the propagation directions of the diurnal waves. SABER sampling patterns enable such definitions. Preliminary analyses of SABER diurnal temperatures show further support for the existence of intermediate- scale waves, and filtering by the mean winds in the upper stratosphere. The westward-propagating waves dominate their eastward counterparts between zonal wavenumbers 7 and 11.

  13. Diurnal and circadian variation of sleep and alertness in men vs. naturally cycling women

    PubMed Central

    Boivin, Diane B.; Shechter, Ari; Boudreau, Philippe; Begum, Esmot Ara; Ng Ying-Kin, Ng Mien Kwong

    2016-01-01

    This study quantifies sex differences in the diurnal and circadian variation of sleep and waking while controlling for menstrual cycle phase and hormonal contraceptive use. We compared the diurnal and circadian variation of sleep and alertness of 8 women studied during two phases of the menstrual cycle and 3 women studied during their midfollicular phase with that of 15 men. Participants underwent an ultradian sleep–wake cycle (USW) procedure consisting of 36 cycles of 60-min wake episodes alternating with 60-min nap opportunities. Core body temperature (CBT), salivary melatonin, subjective alertness, and polysomnographically recorded sleep were measured throughout this procedure. All analyzed measures showed a significant diurnal and circadian variation throughout the USW procedure. Compared with men, women demonstrated a significant phase advance of the CBT but not melatonin rhythms, as well as an advance in the diurnal and circadian variation of sleep measures and subjective alertness. Furthermore, women experienced an increased amplitude of the diurnal and circadian variation of alertness, mainly due to a larger decline in the nocturnal nadir. Our results indicate that women are likely initiating sleep at a later circadian phase than men, which may be one factor contributing to the increased susceptibility to sleep disturbances reported in women. Lower nighttime alertness is also observed, suggesting a physiological basis for a greater susceptibility to maladaptation to night shift work in women. PMID:27621470

  14. Cycle-to-Cycle Variations in the Diurnal Variation of Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Thomas, Simon; Owen, Chris; Owens, Matt; Lockwood, Mike

    2016-04-01

    We examine mean profiles of the diurnal variations in galactic cosmic ray flux using a number of neutron monitors at different magnetic latitudes and longitudes. By splitting all of the hourly neutron monitor data by the solar magnetic polarity and analysing the mean normalised neutron monitor count rates between these, we see that the diurnal variation changes phase by 1-2 hours between the two polarity states for the majority of non-polar neutron monitors. The intensity and variability of a heliospheric magnetic field is analysed for every day and found not to be the cause of the phase change. Some polar neutron monitors, however, show different, smaller amplitude variations in phase between polarity cycles. Time series of the time of the maximum in the diurnal variation are presented between 1965 and 2013. Our results agree with previous work by confirming the presence of a 22-year variation in the peak time of the diurnal variation and a 11-year variation in the amplitude, but also show that not all neutron monitors show the same trend. An analysis of the magnetic latitude dependence of the diurnal variation shows that the time-of-day of the peak and trough of this variation gives opposing changes to the amplitude of the 22-year change. We suggest that this could be due to changes in the configeration of the heliospheric magnetic field for consecutive cycles.

  15. The relative importance of olfaction and vision in a diurnal and a nocturnal hawkmoth.

    PubMed

    Balkenius, Anna; Rosén, Wenqi; Kelber, Almut

    2006-04-01

    Nectar-feeding animals can use vision and olfaction to find rewarding flowers and different species may give different weight to the two sensory modalities. We have studied how a diurnal or nocturnal lifestyle affects the weight given to vision and olfaction. We tested naïve hawkmoths of two species in a wind tunnel, presenting an odour source and a visual stimulus. Although the two species belong to the same subfamily of sphingids, the Macroglossinae, their behaviour was quite different. The nocturnal Deilephila elpenor responded preferably to the odour while the diurnal Macroglossum stellatarum strongly favoured the visual stimulus. Since a nocturnal lifestyle is ancestral for sphingids, the diurnal species, M. stellatarum, has evolved from nocturnal moths that primarily used olfaction. During bright daylight visual cues may have became more important than odour.

  16. Diurnal heat storage in direct-gain passive-solar buildings

    SciTech Connect

    Balcomb, J.D.; Neeper, D.A.

    1983-01-01

    This paper presents a simplified method for predicting temperature swings in direct-gain buildings. It is called the DHC method due to the use of a diurnal heat capacity (DHC). Diurnal heat capacity is a measure of the effective amount of heat stored during a sunny day and then released at night - the typical 24-hour diurnal cycle. This enables prediction of the maximum temperature swings experienced in the building and can be calculated using a single 24-hour harmonic. The advantage is that closed-form analytic solutions can be obtained for a variety of simple and layered-wall configurations. Higher harmonic components are accounted for by a correction factor. The method is suitable for us by hand or on a programmable calculator.

  17. Comparative morphological analysis of the diurnal rhythms in geomagnetic and seismic activity

    NASA Astrophysics Data System (ADS)

    Desherevskii, A. V.; Sidorin, A. Ya.

    2016-12-01

    To verify the hypothesis of the possible influence of geomagnetic variations on seismicity, the structures of the diurnal rhythms of seismicity in Garm research area, Tajikistan, and geomagnetic activity are investigated in detail using the regional index of geomagnetic activity at the Tashkent Astronomical Observatory. We compare (1) the average shape of the diurnal variations and its seasonal changes; (2) temporal changes in special coefficients of the amplitude variations and the diurnal variation stability. It is revealed that the dynamics of the mentioned parameters differ considerably between the geomagnetic and seismic activities. We conclude that the results obtained on the basis of the used data and processing techniques do not confirm the hypothesis of possible influence of weak geomagnetic variations on background seismicity in the Garm region, Tajikistan.

  18. Diurnal cortisol amplitude and fronto-limbic activity in response to stressful stimuli.

    PubMed

    Cunningham-Bussel, Amy C; Root, James C; Butler, Tracy; Tuescher, Oliver; Pan, Hong; Epstein, Jane; Weisholtz, Daniel S; Pavony, Michelle; Silverman, Michael E; Goldstein, Martin S; Altemus, Margaret; Cloitre, Marylene; Ledoux, Joseph; McEwen, Bruce; Stern, Emily; Silbersweig, David

    2009-06-01

    The development and exacerbation of many psychiatric and neurologic conditions are associated with dysregulation of the hypothalamic pituitary adrenal (HPA) axis as measured by aberrant levels of cortisol secretion. Here we report on the relationship between the amplitude of diurnal cortisol secretion, measured across 3 typical days in 18 healthy individuals, and blood oxygen level dependant (BOLD) response in limbic fear/stress circuits, elicited by in-scanner presentation of emotionally negative stimuli, specifically, images of the World Trade Center (WTC) attack. Results indicate that subjects who secrete a greater amplitude of cortisol diurnally demonstrate less brain activation in limbic regions, including the amygdala and hippocampus/parahippocampus, and hypothalamus during exposure to traumatic WTC-related images. Such initial findings can begin to link our understanding, in humans, of the relationship between the diurnal amplitude of a hormone integral to the stress response, and those neuroanatomical regions that are implicated as both modulating and being modulated by that response.

  19. Wavy Lineaments on Europa: Fracture Propagation into Combined Nonsynchronous and Diurnal Stress Fields

    NASA Technical Reports Server (NTRS)

    Crawford, Zane; Pappalardo, Robert T.; Barr, Amy C.; Gleeson, Damhnait; Mullen, McCall; Nimmo, Francis; Stempel, Michelle M.; Wahr, John

    2005-01-01

    Understanding the processes that have operated on Europa and the manner in which they may have changed through time is fundamental to understanding the satellite's geology and present-day habitability. Previous studies have shown that lineament patterns on Europa can be explained by accumulation of tensile stress from slow nonsynchronous rotation (NSR), while the cycloidal planforms of other Europan lineaments can be explained if fractures propagate through a diurnally changing tensile stress field. We find that fractures propagated into combined diurnal and NSR stress fields can be "wavy" in planform for NSR stress accumulated over 2 to 8 of ice shell rotation and average propagation speeds of approx. 1 to 3 m/s. The variety of Europa's observed lineament planforms from cycloidal, to wavy, to arcuate can be produced by accumulation of NSR stress relative to the diurnal stress field. Varying proportions of these stress mechanisms plausibly may be related to a time-variable (slowing) NSR rate.

  20. Retrograde diurnal motion of the instantaneous rotation axis observed by a large ring laser gyroscope

    NASA Astrophysics Data System (ADS)

    Tian, W.

    2017-01-01

    Ring laser gyroscope technique directly senses the Earth's instantaneous rotation pole (IRP), whose polar motion contains strong retrograde diurnal components induced by external torques due to the gravitational attraction of the Moon and Sun. The first direct measurement of this retrograde diurnal motion with three large ring lasers was reported by Schreiber et al. (J Geophys Res 109(B18):B06405, significant increase in precision and stability of ring laser gyroscopes; however, precise determination of amplitude and phase at main partial waves has not been given in the literature. In this paper, I will report on determination of the retrograde diurnal motion of the IRP at main partial waves (Oo_1, J_1, K_1, M_1, O_1, Q_1) by the ring laser "G", located in Wettzell, Germany, which is the most stable one amongst the currently running large ring laser gyroscopes.

  1. Seasonal and Diurnal Variations of Hg(0) Over New England

    NASA Astrophysics Data System (ADS)

    Mao, H.; Talbot, R.; Sigler, J.; Sive, B.; Hegarty, J.

    2007-12-01

    Diurnal to interannual variability of Hg° over New England was investigated using multiple years of Hg° measurements at two inland sites, Thompson Farm (TF, 43.11° N, 70.95° W, 24 m, 25 km inland) and Pac Monadnock (PM, 42.86° N, 71.88° W, 700 m, 180 km inland), and one summer of measurements from a marine site, Appledore Island (AI, 42.97° N, 70.62° W, sea level), from the University of New Hampshire AIRMAP observing network. Possible sources were identified via a thorough examination of relationships between Hg° and a number of trace gases, e.g., CO, CO2, CH4, NOy, NO, SO2, and VOCs. The measurements of Hg at TF showed distinct seasonality with an annual maxima in late winter - early spring and a minima in early fall, with large day-to-day variation. A decreasing trend in the mixing ratio of Hg over the time period of March - September occurred at a rate of 0.5 - 0.6 ppqv d-1 for all years except 2004 (0.3 ppqv d-1). Measurements of Hg° at the elevated site PM exhibited much smaller daily and annual variation, particularly reflected in the slower warm season decline (relative to TF) of 0.2 and 0.3 ppqv d-1 in 2005 and 2006 respectively. The AI data appeared to track the variation observed at TF albeit with much higher minima. Hg° was correlated most strongly with CO and NOy in winter suggesting that anthropogenic emissions were the primary source of Hg° . Applying the Hg° - CO relationship, we found that the seasonally averaged Hg° mixing ratio of ~160 ppqv at PM can be considered the regional background level. The positive Hg° -NOy correlation along the lower boundary of all data points indicated dry deposition as a stronger sink for Hg° than suggested by previous studies. We estimated a dry deposition velocity for Hg° of 0.17 - 0.20 cm s-1, and a lifetime of ~11 days in the local PBL at TF. Correlation between Hg° and CHBr3 at both TF and AI suggested a role of the oceanic source influencing the ambient levels of Hg° in the marine and coastal

  2. On the sensitivity of the diurnal cycle in the Amazon to convective intensity

    PubMed Central

    Taylor, Patrick C.; Dodson, Jason B.; Tawfik, Ahmed B.

    2016-01-01

    Abstract Climate and reanalysis models contain large water and energy budget errors over tropical land related to the misrepresentation of diurnally forced moist convection. Motivated by recent work suggesting that the water and energy budget is influenced by the sensitivity of the convective diurnal cycle to atmospheric state, this study investigates the relationship between convective intensity, the convective diurnal cycle, and atmospheric state in a region of frequent convection—the Amazon. Daily, 3‐hourly satellite observations of top of atmosphere (TOA) fluxes from Clouds and the Earth's Radiant Energy System Ed3a SYN1DEG and precipitation from Tropical Rainfall Measuring Mission 3B42 data sets are collocated with twice daily Integrated Global Radiosonde Archive observations from 2002 to 2012 and hourly flux tower observations. Percentiles of daily minimum outgoing longwave radiation are used to define convective intensity regimes. The results indicate a significant increase in the convective diurnal cycle amplitude with increased convective intensity. The TOA flux diurnal phase exhibits 1–3 h shifts with convective intensity, and precipitation phase is less sensitive. However, the timing of precipitation onset occurs 2–3 h earlier and the duration lasts 3–5 h longer on very convective compared to stable days. While statistically significant changes are found between morning atmospheric state and convective intensity, variations in upper and lower tropospheric humidity exhibit the strongest relationships with convective intensity and diurnal cycle characteristics. Lastly, convective available potential energy (CAPE) is found to vary with convective intensity but does not explain the variations in Amazonian convection, suggesting that a CAPE‐based convective parameterization will not capture the observed behavior without incorporating the sensitivity of convection to column humidity. PMID:27867784

  3. On the sensitivity of the diurnal cycle in the Amazon to convective intensity

    NASA Astrophysics Data System (ADS)

    Itterly, Kyle F.; Taylor, Patrick C.; Dodson, Jason B.; Tawfik, Ahmed B.

    2016-07-01

    Climate and reanalysis models contain large water and energy budget errors over tropical land related to the misrepresentation of diurnally forced moist convection. Motivated by recent work suggesting that the water and energy budget is influenced by the sensitivity of the convective diurnal cycle to atmospheric state, this study investigates the relationship between convective intensity, the convective diurnal cycle, and atmospheric state in a region of frequent convection—the Amazon. Daily, 3-hourly satellite observations of top of atmosphere (TOA) fluxes from Clouds and the Earth's Radiant Energy System Ed3a SYN1DEG and precipitation from Tropical Rainfall Measuring Mission 3B42 data sets are collocated with twice daily Integrated Global Radiosonde Archive observations from 2002 to 2012 and hourly flux tower observations. Percentiles of daily minimum outgoing longwave radiation are used to define convective intensity regimes. The results indicate a significant increase in the convective diurnal cycle amplitude with increased convective intensity. The TOA flux diurnal phase exhibits 1-3 h shifts with convective intensity, and precipitation phase is less sensitive. However, the timing of precipitation onset occurs 2-3 h earlier and the duration lasts 3-5 h longer on very convective compared to stable days. While statistically significant changes are found between morning atmospheric state and convective intensity, variations in upper and lower tropospheric humidity exhibit the strongest relationships with convective intensity and diurnal cycle characteristics. Lastly, convective available potential energy (CAPE) is found to vary with convective intensity but does not explain the variations in Amazonian convection, suggesting that a CAPE-based convective parameterization will not capture the observed behavior without incorporating the sensitivity of convection to column humidity.

  4. On the sensitivity of the diurnal cycle in the Amazon to convective intensity.

    PubMed

    Itterly, Kyle F; Taylor, Patrick C; Dodson, Jason B; Tawfik, Ahmed B

    2016-07-27

    Climate and reanalysis models contain large water and energy budget errors over tropical land related to the misrepresentation of diurnally forced moist convection. Motivated by recent work suggesting that the water and energy budget is influenced by the sensitivity of the convective diurnal cycle to atmospheric state, this study investigates the relationship between convective intensity, the convective diurnal cycle, and atmospheric state in a region of frequent convection-the Amazon. Daily, 3-hourly satellite observations of top of atmosphere (TOA) fluxes from Clouds and the Earth's Radiant Energy System Ed3a SYN1DEG and precipitation from Tropical Rainfall Measuring Mission 3B42 data sets are collocated with twice daily Integrated Global Radiosonde Archive observations from 2002 to 2012 and hourly flux tower observations. Percentiles of daily minimum outgoing longwave radiation are used to define convective intensity regimes. The results indicate a significant increase in the convective diurnal cycle amplitude with increased convective intensity. The TOA flux diurnal phase exhibits 1-3 h shifts with convective intensity, and precipitation phase is less sensitive. However, the timing of precipitation onset occurs 2-3 h earlier and the duration lasts 3-5 h longer on very convective compared to stable days. While statistically significant changes are found between morning atmospheric state and convective intensity, variations in upper and lower tropospheric humidity exhibit the strongest relationships with convective intensity and diurnal cycle characteristics. Lastly, convective available potential energy (CAPE) is found to vary with convective intensity but does not explain the variations in Amazonian convection, suggesting that a CAPE-based convective parameterization will not capture the observed behavior without incorporating the sensitivity of convection to column humidity.

  5. Research of the diurnal soil respiration dynamic in two typical vegetation communities in Tianjin estuarine wetland

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Meng, W. Q.; Li, H. Y.

    2016-08-01

    Understanding the differences and diurnal variations of soil respiration in different vegetation communities in coastal wetland is to provide basic reliable scientific evidence for the carbon "source" function of wetland ecosystems in Tianjin.Measured soil respiration rate which changed during a day between two typical vegetation communities (Phragmites australis, Suaeda salsa) in coastal wetland in October, 2015. Soil temperature and moisture were measured at the same time. Each of the diurnal curves of soil temperature in two communities had a single peak value, and the diurnal variations of soil moisture showed a "two peak-one valley" trend. The diurnal dynamic of soil respiration under the two communities had obvious volatility which showed a single peak form with its maximum between 12:00-14:00 and minimum during 18:00. The diurnal average of soil respiration rate in Phragmites australis communities was 3.37 times of that in Suaeda salsa communities. Significant relationships were found by regression analysis among soil temperature, soil moisture and soil respiration rate in Suaeda salsa communities. There could be well described by exponential models which was y = -0.245e0.105t between soil respiration rate and soil temperature, by quadratic models which was y = -0.276×2 + 15.277× - 209.566 between soil respiration rate and soil moisture. But the results of this study showed that there were no significant correlations between soil respiration and soil temperature and soil moisture in Phragmites australis communities (P > 0.05). Therefore, under the specific wetland environment conditions in Tianjin, soil temperature and moisture were not main factors influencing the diurnal variations of soil respiration rate in Phragmites australis communities.

  6. A numerical model of nonmigrating diurnal tides between the surface and 65 km

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.; Leovy, Conway B.

    1995-01-01

    Observations of surface pressure and middle atmosphere temperatures and winds indicate that a substantial nonmigrating component is present in the diurnal tide. The nonmigrating tides, which propagate with a zonal phase speed that is different from the earth's rotation, are attributed to the diurnal heating of geographically fixed sources. In this study we utilize a classical tidal model to examine the propagation characteristics of diurnal tides. The global fields of tropospheric sensible, radiative, and latent heating used to drive the model are supplied from summer and winter diurnal climatologies of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM2). A novel aspect of this study is the focus on the relative importance of the nonmigrating components. The classical model successfully reproduces many observed features of the low-latitude diurnal surface pressure tides. In the middle atmosphere, the simulated migrating (or sun-synchronous) tide shows qualitative agreement with November-March Limb Infrared Monitor of the Stratosphere (LIMS) observations. Tropospheric solar heating is clearly the dominant driving force for the migrating tide, with secondary contributions from boundary-layer sensible heating and tropospheric latent heat release. The leading modes of the zonal mean tide are also driven chiefly by tropospheric solar heating. The higher-order modes of the zonal mean and eastward propagating tides may be attributed to the joint effects of tropospheric solar heating, sensible heating, and latent heat release. The LIMS and other data reveal features that cannot be explained or examined within the context of the classical model used in the present study. These include upward phase propagation, vertical attenuation, and temporal variations in the migrating diurnal tide.

  7. Physiological responses of soil crust-forming cyanobacteria to diurnal temperature variation.

    PubMed

    Wang, Weibo; Wang, Yingcai; Shu, Xiao; Zhang, Quanfa

    2013-01-01

    The optimum growth of soil crust-forming cyanobacterial species occurs between 21 and 30 °C. When the temperature decreases below -5 °C, the liquid water in the cyanobacterial cells may freeze. In the natural environment, the temperature gradually decreases from autumn to winter, and the diurnal temperatures fluctuate enormously. It was hypothesized that the physiology of cyanobacterial cells changes in later autumn to acclimatize the cells to the upcoming freezing temperatures. In the present study, an incubation experiment in growth chambers was designed to stimulate the responses of cyanobacterial cells to diurnal temperature variations before freezing in late autumn. The results showed that "light" cyanobacterial soil crusts are more tolerant to diurnal temperature fluctuations than "dark" cyanobacterial soil crusts. After the first diurnal temperature cycle between 24 and -4 °C, the malondialdehyde (MDA) contents increased and the photosynthetic activity decreased. The superoxide dismutase activity increased, more extracellular polysaccharides (EPS) were secreted and the ratios of the light-harvesting and light-screening pigments decreased. With increasing numbers of diurnal temperature cycles, the MDA contents and photosynthetic activity gradually returned to their initial levels. Our results suggest that there are at least three pathways by which crust-forming cyanobacteria acclimate to the diurnal temperature cycles in the late autumn in the Hopq Desert, Northwest China. These three pathways include increased secretion of EPS, regulation of the ratios of light-harvesting and light-screening pigments, and activation of the antioxidant system. The results also indicate that late autumn is a critical period for the protection and restoration of the cyanobacterial soil crusts in the Hopq Desert.

  8. Study of the Cosmic Ray Diurnal Anisotropy During Different Solar and Magnetic Conditions

    NASA Astrophysics Data System (ADS)

    Singh, Munendra; Badruddin

    2006-02-01

    The pressure-corrected hourly counting rate data of four neutron monitor stations have been employed to study the variation of cosmic ray diurnal anisotropy for a period of about 50 years (1955-2003). These neutron monitors, at Oulu (Rc = 0.78 GV), Deep River (Rc = 1.07 GV), Climax (Rc = 2.99 GV), and Huancayo (Rc = 12.91 GV) are well distributed on the earth over different latitudes and their data have been analyzed. The amplitude of the diurnal anisotropy varies with a period of one solar cycle (~11 years), while the phase varies with a period of two solar cycles (~22 years). In addition to its variation on year-to-year basis, the average diurnal amplitude and phase has also been calculated by grouping the days for each solar cycle, viz. 19, 20, 21, 22, and 23. As a result of these groupings over solar cycles, no significant change in the diurnal vectors (amplitude as well as phase) from one cycle to other has been observed. Data were analyzed by arranging them into groups on the basis of the polarity of the solar polar magnetic field and consequently on the basis of polarity states of the heliosphere (A > 0 and A < 0). Difference in time of maximum of diurnal anisotropy (shift to earlier hours) is observed during A < 0 (1970s, 1990s) polarity states as compared to anisotropy observed during A > 0 (1960s, 1980s). This shift in phase of diurnal anisotropy appears to be related to change in preferential entry of cosmic ray particles (via the helioequatorial plane or via solar poles) into the heliosphere due to switch of the heliosphere from one physical/magnetic state to another following the solar polar field reversal.

  9. Diurnal and Nocturnal Pollination of Marginatocereus marginatus (Pachycereeae: Cactaceae) in Central Mexico

    PubMed Central

    DAR, SALEEM; ARIZMENDI, Ma. del CORO; VALIENTE-BANUET, ALFONSO

    2006-01-01

    • Background and Aims Chiropterophillous and ornithophillous characteristics can form part of a single reproductive strategy in plants that have flowers with diurnal and nocturnal anthesis. This broader pollination strategy can ensure seed set when pollinators are scarce or unpredictable. This appears to be true of hummingbirds, which presumably pollinate Marginatocereus marginatus, a columnar cactus with red nocturnal and diurnal flowers growing as part of dense bat-pollinated columnar cacti forests in arid regions of central Mexico. The aim of this study was to study the floral biology of M. marginatus, and evaluate the effectiveness of nocturnal vs. diurnal pollinators and the contribution of each pollinator group to overall plant fitness. • Methods Individual flower buds were marked and followed to evaluate flower phenology and anthesis time. Flowers and nectar production were measured. An exclusion experiment was conducted to measure the relative contribution of nocturnal and diurnal pollinators to seed set. • Key Results Marginatocereus marginatus has red hermaphroditic flowers with nocturnal and diurnal anthesis. The plant cannot produce seeds by selfing and was pollinated during the day by hummingbirds and during the night by bats, demonstrating that both pollinator groups were important for plant reproduction. Strong pollen limitation was found in the absence of one of the pollinator guilds. • Conclusions Marginatocereus marginatus has an open pollination system in which both diurnal and nocturnal pollinators are needed to set seeds. This represents a fail-safe pollination system that can ensure both pollination, in a situation of low abundance of one of the pollinator groups (hummingbirds), and high competition for nocturnal pollinators with other columnar cacti that bloom synchronously with M. marginatus in the Tehuacan Valley, Mexico. PMID:16394025

  10. Diurnal variability in orthostatic tachycardia: implications for the postural tachycardia syndrome.

    PubMed

    Brewster, Jordan A; Garland, Emily M; Biaggioni, Italo; Black, Bonnie K; Ling, John F; Shibao, Cyndya A; Robertson, David; Raj, Satish R

    2012-01-01

    Patients with POTS (postural tachycardia syndrome) have excessive orthostatic tachycardia (>30 beats/min) when standing from a supine position. HR (heart rate) and BP (blood pressure) are known to exhibit diurnal variability, but the role of diurnal variability in orthostatic changes of HR and BP is not known. In the present study, we tested the hypothesis that there is diurnal variation of orthostatic HR and BP in patients with POTS and healthy controls. Patients with POTS (n=54) and healthy volunteers (n=26) were admitted to the Clinical Research Center. Supine and standing (5 min) HR and BP were obtained in the evening on the day of admission and in the following morning. Overall, standing HR was significantly higher in the morning (102±3 beats/min) than in the evening (93±2 beats/min; P<0.001). Standing HR was higher in the morning in both POTS patients (108±4 beats/min in the morning compared with 100±3 beats/min in the evening; P=0.012) and controls (89±3 beats/min in the morning compared with 80±2 beats/min in the evening; P=0.005) when analysed separately. There was no diurnal variability in orthostatic BP in POTS. A greater number of subjects met the POTS HR criterion in the morning compared with the evening (P=0.008). There was significant diurnal variability in orthostatic tachycardia, with a great orthostatic tachycardia in the morning compared with the evening in both patients with POTS and healthy subjects. Given the importance of orthostatic tachycardia in diagnosing POTS, this diurnal variability should be considered in the clinic as it may affect the diagnosis of POTS.

  11. Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate

    NASA Technical Reports Server (NTRS)

    Mackerras, David; Darveniza, Mat; Orville, Richard E.; Williams, Earle R.; Goodman, Steven J.

    1999-01-01

    A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approximately equals 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approximately equals 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels. The comparisons were made for the northern winter (Nov.-Feb.), the equinox (Mar., Apr., Sept., Oct.), the northern summer (May-Aug.), and the whole year.

  12. Role of Vagal Innervation in Diurnal Rhythm of Intestinal Peptide Transporter 1 (PEPT1)

    PubMed Central

    Qandeel, Hisham G.; Alonso, Fernando; Hernandez, David J.; Duenes, Judith A.; Zheng, Ye; Scow, Jeffrey S.; Sarr, Michael G.

    2010-01-01

    BACKGROUND: Protein is absorbed predominantly as di/tripeptides via H+/peptide cotransporter-1 (PEPT1). We demonstrated previously diurnal variations in expression and function of duodenal and jejunal but not ileal PEPT1; neural regulation of this pattern is unexplored. HYPOTHESIS: Complete abdominal vagotomy abolishes diurnal variations in gene expression and transport function of PEPT1. METHODS: 24 rats maintained in a 12-h light/dark room [6AM-6PM] underwent abdominal vagotomy; 24 other rats were controls. Four weeks later, mucosal levels of mRNA and protein were measured at 9AM, 3PM, 9PM, and 3AM (n=6 each) by quantitative real time-PCR and Western blots, respectively; transporter-mediated uptake of di-peptide (Gly-Sar) was measured by the everted-sleeve technique. RESULTS: Diurnal variation in mRNA, as in controls, was retained post-vagotomy in duodenum and jejunum (peak at 3PM, p<0.05) but not in ileum. Diurnal variations in expression of protein and Gly-Sar uptake, however, were absent post-vagotomy (p>0.3). Similar to controls, maximal uptake was in jejunum after vagotomy (Vmax-nmol/cm/min: jejunum vs. duodenum and ileum; 163 vs. 88 and 71 at 3AM; p<0.04); Km remained unchanged. CONCLUSIONS: Vagal innervation appears to mediate in part diurnal variations in protein expression and transport function of PEPT1, but not diurnal variation in mRNA expression of PEPT1. PMID:19707837

  13. Diurnal and Seasonal Change in Stem Respiration of Larix principis-rupprechtii Trees, Northern China

    PubMed Central

    Yang, Yan; Zhao, Miao; Xu, Xiangtao; Sun, Zhenzhong; Yin, Guodong; Piao, Shilong

    2014-01-01

    Stem respiration is a critical and uncertain component of ecosystem carbon cycle. Few studies reported diurnal change in stem respiration as well as its linkage with climate. In this study, we investigated the diurnal and seasonal change in stem respiration and its linkage with environmental factors, in larch plantations of northern China from 2010 to 2012. The stem respiration per unit surface area (RS) showed clear diurnal cycles, ranging from 1.65±0.10 to 2.69±0.15 µmol m−2 s−1, increased after 6∶00, peaked at 15∶00 and then decreased. Both stem temperature and air temperature show similar diurnal pattern, while the diurnal pattern of air relative humidity is just the opposite to Rs. Similar to the diurnal cycles, seasonal change in RS followed the pattern of stem temperature. RS increased from May (1.28±0.07 µmol m−2 s−1) when the stem temperature was relatively low and peaked in July (3.02±0.10 µmol m−2 s−1) when the stem temperature was also the highest. Further regression analyses show that RS exponentially increases with increasing temperature, and the Q10 of Rs at mid daytime (1.97±0.17 at 12∶00 and 1.96±0.10 at 15∶00) is significantly lower than that of mid nighttime (2.60±0.14 at 00∶00 and 2.71±0.25 at 03∶00) Q10. This result not only implies that Rs is more sensitive to night than day warming, but also highlights that temperature responses of Rs estimated by only daytime measurement can lead to underestimated stem respiration increase under global warming, especially considering that temperature increase is faster during nighttime. PMID:24586668

  14. A diurnal study of the electrical structure of the equatorial middle atmosphere

    NASA Technical Reports Server (NTRS)

    Croskey, C. L.; Hale, L. C.; Mitchell, J. D.; Muha, D.; Maynard, N. C.

    1985-01-01

    Electrical parameters measured from 115 km down to below 20 km during the Project Condor campaign at the Punta Lobos Rocket Range near Lima, Peru, are presented. Ten rocket-launched payloads measured electrical conductivity. A strong diurnal influence due to solar ultraviolet radiation is shown. Nine of the payloads also measured electric fields. No large mesospheric vertical electric fields are found in the data. A calculation of the dc global conduction current density at 18 km is smaller than previously measured at low latitudes and does not show the conventional diurnal variation.

  15. The Seasonal and Diurnal Variations of Lower and Middle Atmosphere Temperatures at the South Pole

    NASA Astrophysics Data System (ADS)

    Chu, X.; Pan, W.; Gardner, C. S.

    2001-05-01

    An Fe Boltzmann Temperature Lidar was operated at the Amundsen-Scott South Pole Station from 1999-2001. Temperature profiles were obtained by combining the lidar data from 30-75 km and the balloon data from ground to around 35 km. We summarize the seasonal variations of the troposphere up to mesosphere temperatures at the South Pole. Furthermore, more than 24 hours continuous lidar observations at the South Pole allow us to study the diurnal variations of the stratosphere temperatures. We also present the seasonal and diurnal variations of the mesospheric Fe densities, which indicate the effects of Fe chemistry and the persistent oscillations at the South Pole.

  16. Diurnal variability of the hydrologic cycle in a general circulation model

    NASA Technical Reports Server (NTRS)

    Randall, David A.; Dazlich, Donald A.; HARSHVARDHAN

    1991-01-01

    In the present Colorado State University GCM simulation-based analysis of the diurnal and semidiurnal variability of precipitation, precipitable water, evaporation, cloudiness, horizontal moisture flux convergence, and cloud radiative forcing, a realistic afternoon precipitation maximum is obtained over land in warm rainy regions, as well as an early morning maximum over the oceans. The model has been further used to investigate the bases for the oceanic diurnal-precipitation cycle; the results thus obtained indicate that such an oceanic cycle occurs even in the absence of neighboring continents, and tends to have a morning maximum, although the observed phenomenon is generally stronger than the results indicate.

  17. Strong Diurnal Surface Currents in the Bay of La Paz, Mexico

    NASA Astrophysics Data System (ADS)

    Zaitsev, O. V.; Rabinovich, A.; Thomson, R.; Silverberg, N.

    2009-12-01

    To characterize the tidal regime and vertical structure of tidal currents in the Bay of La Paz an Acoustic Doppler Current Profiler (ADCP) was deployed at a depth of about 185 m in the northern part of the bay in the period from 17 February to 25 October 2007. Flow variability was dominated by tidal motions that accounted for 43% (33% diurnal, 10% semidiurnal) of the total kinetic energy. The currents measured by the ADCP were harmonically analyzed with focus on five constituents: K1, O1, M2, S2 and S1. Our results indicate that diurnal and semidiurnal currents in the Bay of La Paz are generated by two dominant mechanisms: radiational (seabreeze) and gravitational (tidal) forcing. The first mechanism is responsible for the generation of surface-intensified counterclockwise (CCW) rotary diurnal (up to 55 cm/s) and semidiurnal (up to 20 cm/s) currents in the upper mixed layer while the second is responsible for the relatively weak (~3-10 cm/s) nearly barotropic clockwise (CW) rotary tidal currents observed throughout the remainder of the water column. Motions in the upper layer were dominated by strong, counterclockwise S1 diurnal currents that were coherent with the counterclockwise local seabreeze. Significant semidiurnal S2 radiational tidal currents, as well as S3 and S4 currents, were also highly coherent with the wind. In contrast to the cross-bay orientation prevalent in tidal ellipses of other constituents, tidal ellipses for the S1 and S2 bands were oriented normal to the entrance of the bay with semi-major axes of up to 55 and 20 cm/s, respectively. Coherent (“deterministic”) tidal currents account for roughly 65 % (59% for S1) of the total diurnal kinetic energy in the surface layer, while incoherent tidal motions account for 18% and background noise for 17% of the kinetic energy. Below 30 m depth, the corresponding estimates are 40%, 32% and 28%, respectively. The persistent, surface-intensified CCW rotary diurnal currents observed at the mooring site

  18. A diurnal study of the electrical structure of the equatorial middle atmosphere

    NASA Astrophysics Data System (ADS)

    Croskey, C. L.; Hale, L. C.; Mitchell, J. D.; Muha, D.; Maynard, N. C.

    1985-10-01

    Electrical parameters measured from 115 km down to below 20 km during the Project Condor campaign at the Punta Lobos Rocket Range near Lima, Peru, are presented. Ten rocket-launched payloads measured electrical conductivity. A strong diurnal influence due to solar ultraviolet radiation is shown. Nine of the payloads also measured electric fields. No large mesospheric vertical electric fields are found in the data. A calculation of the dc global conduction current density at 18 km is smaller than previously measured at low latitudes and does not show the conventional diurnal variation.

  19. Imaging of ultraweak spontaneous photon emission from human body displaying diurnal rhythm.

    PubMed

    Kobayashi, Masaki; Kikuchi, Daisuke; Okamura, Hitoshi

    2009-07-16

    The human body literally glimmers. The intensity of the light emitted by the body is 1000 times lower than the sensitivity of our naked eyes. Ultraweak photon emission is known as the energy released as light through the changes in energy metabolism. We successfully imaged the diurnal change of this ultraweak photon emission with an improved highly sensitive imaging system using cryogenic charge-coupled device (CCD) camera. We found that the human body directly and rhythmically emits light. The diurnal changes in photon emission might be linked to changes in energy metabolism.

  20. Diurnal and seasonal variation in physico-chemical conditions within intertidal rock pools

    NASA Astrophysics Data System (ADS)

    Morris, S.; Taylor, A. C.

    1983-09-01

    A study of the diurnal and seasonal variation in the physico-chemical conditions within intertidal rock pools on the West coast of Scotland was undertaken to provide data on the environmental conditions experienced by animals inhabiting these pools. The temperature, pH, partial pressure of oxygen ( PO2) and salinity were measured every hour for 24 h and the total alkalinity, partial pressure of carbon dioxide ( PCO2) and carbon dioxide content ( CCO2) calculated. This sampling regime was carried out once a month for 12 months to determine the extent of seasonal variation in conditions within temperate pools. Large diurnal variations were recorded in nearly all the physico-chemical parameters measured. The greatest variation was recorded in the temperature and PO2 of the water but significant changes in pH and PCO2 were also recorded. Total alkalinity varied little during any 24 h period but carbonate alkalinity, which was always lower than total alkalinity, showed slightly greater variation. There was also considerable variation in the magnitude of these diurnal changes between pools at different heights on the shore. Diurnal variation in the physico-chemical conditions within the pools were observed throughout the year although the magnitude of these changes varied seasonally. Detailed studies on individual pools demonstrated that appreciable local variation existed in the physico-chemical conditions within each pool.

  1. SIMULATION OF SUMMER-TIME DIURNAL BACTERIAL DYNAMICS IN THE ATMOSPHERIC SURFACE LAYER

    EPA Science Inventory

    A model was prepared to simulate the observed concentration dynamics of culturable bacteria in the diurnal summer atmosphere at a Willamette River Valley, Oregon location. The meteorological and bacterial mechanisms included in a dynamic null-dimensional model with one-second tim...

  2. A diurnal reflectance model using grass: Surface-substrate interaction and inverse solution - October 16, 2011

    EPA Science Inventory

    We report an analysis of canopy reflectance (ρ) experiment, using hand-held radiometer to measure distribution of biomass in a grass field. The analysis: 1) separates the green-fraction from thatch and soil background, 2) accounts for the changing diurnal ρ with the sun elevation...

  3. Global characteristics in the diurnal variations of the thermospheric temperature and composition

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Hedin, A. E.; Reber, C. A.; Carignan, G. R.

    1973-01-01

    Global characteristics in the diurnal components of OGO-6 neutral mass spectrometer measurements near 450 km are discussed qualitatively as well as quantitatively on the basis of a theoretical model. Observations and conclusion are summarized: (1) During equinox the temperature maximum occurs after 1600 LT at the equator and shifts toward 1500 LT at the poles, while the oxygen concentration at 450 km peaks about one hour earlier. (2) There is general agreement between the magnitudes and phases of the diurnal, semidiurnal and terdiuranal temperature components at 450 km from theory as well as OGO-6 and radar backscatter measurements. (3) The maximum in the diurnal variation of He is observed near 1030 LT consistent with theoretical results which further emphasize the importance of dynamics and diffusion. (4) During solstice conditions the diurnal temperature maximum shifts toward later local times, in substantial agreement with radar temperature measurements. (5) the temperature-oxygen density phase difference at 450 km is observed to decrease with latitude from the winter toward the summer hemisphere, where oxygen may even peak after the temperature at high latitudes.

  4. Diurnal Regulation of the Brassinosteroid-Biosynthetic CPD Gene in Arabidopsis1[W

    PubMed Central

    Bancos, Simona; Szatmári, Anna-Mária; Castle, Julie; Kozma-Bognár, László; Shibata, Kyomi; Yokota, Takao; Bishop, Gerard J.; Nagy, Ferenc; Szekeres, Miklós

    2006-01-01

    Plant steroid hormones, brassinosteroids (BRs), are essential for normal photomorphogenesis. However, the mechanism by which light controls physiological functions via BRs is not well understood. Using transgenic plants carrying promoter-luciferase reporter gene fusions, we show that in Arabidopsis (Arabidopsis thaliana) the BR-biosynthetic CPD and CYP85A2 genes are under diurnal regulation. The complex diurnal expression profile of CPD is determined by dual, light-dependent, and circadian control. The severely decreased expression level of CPD in phytochrome-deficient background and the red light-specific induction in wild-type plants suggest that light regulation of CPD is primarily mediated by phytochrome signaling. The diurnal rhythmicity of CPD expression is maintained in brassinosteroid insensitive 1 transgenic seedlings, indicating that its transcriptional control is independent of hormonal feedback regulation. Diurnal changes in the expression of CPD and CYP85A2 are accompanied by changes of the endogenous BR content during the day, leading to brassinolide accumulation at the middle of the light phase. We also show that CPD expression is repressed in extended darkness in a BR feedback-dependent manner. In the dark the level of the bioactive hormone did not increase; therefore, our data strongly suggest that light also influences the sensitivity of plants to BRs. PMID:16531479

  5. Diurnal Convection Peaks over the Eastern Indian Ocean over Sumatra during Different MJO Phases

    NASA Astrophysics Data System (ADS)

    Fujita, M.; Nasuno, T.; Yoneyama, K.

    2015-12-01

    The diurnal convection peak characteristics over the eastern Indian Ocean over the island of Sumatra during different phases of the Madden-Julian oscillation (MJO) were investigated. During MJO phases 2 to 3 (P2 and P3) defined by Wheeler and Hendon (2004), prominent diurnal variation in convection was observed by satellites when moderate low-level westerly winds were dominant over the eastern Indian Ocean. The diurnal convection peaks were prominent over the island of Sumatra in the evening, while migrations of the convection toward the Indian Ocean were observed in the early morning. By using the Global Positioning System around the western region offshore of Sumatra, a significant reduction in water vapor was observed from evening until midnight, compensating for the upward motion over the island. During midnight to early morning, the water vapor increased in the western offshore region as the convections migrated from the island. During P2 to P3, the atmosphere over the eastern Indian Ocean contains abundant water vapor, while the Maritime Continent is fairly well heated by solar radiation under calm conditions. This situation should be favorable for the development of two diurnal convection peaks: the evening convection over the land induced by solar radiative heating and the midnight convection over the ocean triggered by convergence of the low-level westerly wind and the land breeze.

  6. Diurnal temperature range compression hastens berry development and modifies flavonoid partitioning in grapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperatures during the day and night are known to influence grape berry metabolism and resulting composition. In this study, the flavonoid composition of field-grown Vitis vinifera L. cv. Merlot berries was investigated as a function of diurnal temperature range (DTR). The DTR was compressed by c...

  7. Long-Term Effectiveness of the Response Restriction Method for Establishing Diurnal Bladder Control

    ERIC Educational Resources Information Center

    van Oorsouw, Wietske M. W. J.; Duker, P. C.; Melein, L.; Averink, M.

    2009-01-01

    The long-term effectiveness of the response restriction method for establishing diurnal bladder control was assessed with 48 participants with intellectual disabilities. Intervals of assessment ranged from 28 to 66 months across the individuals following initial baseline. Difference scores in terms of the mean number of toileting accidents per…

  8. Diurnal Variability of Organic Carbon Distributions and Phytoplankton in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    de Meo, O.; Mannino, A.

    2009-12-01

    The full effects of fossil fuel combustion on the carbon cycle are not well understood. To address rising environmental concerns, NASA is studying a new satellite mission concept called Geostationary Coastal and Air Pollution Events (GEO-CAPE), which will take more frequent images than the two current ocean color satellite sensors, SeaWiFS and MODIS-Aqua. GEO-CAPE will be able to study the diurnal variation associated with natural processes, climate change, and other human impacts on the coastal ocean. The purpose of this study was to collect preliminary data for organic carbon distributions and phytoplankton in Chesapeake Bay through high frequency sampling. Local water samples showed greater regional and daily differences in colored dissolved organic matter (CDOM), which may be explained by river discharge. Small diurnal variation likely due to the tidal cycle was also observed. Mean particulate organic carbon (POC) showed more substantial diurnal variation, which coincided with diurnal variability in chlorophyll from algal biomass. This variability supports the need for the GEO-CAPE satellite mission to further our understanding of the ocean’s role in the carbon cycle.

  9. Reproductive biology of Echinopsis terscheckii (Cactaceae): the role of nocturnal and diurnal pollinators.

    PubMed

    Ortega-Baes, P; Saravia, M; Sühring, S; Godínez-Alvarez, H; Zamar, M

    2011-01-01

    The aim of this study was to analyse the reproductive biology of Echinopsis terscheckii, a species endemic to northwest Argentina that has nocturnal flowers. We expected that this species had a generalised pollination system, with moths and diurnal visitors as the primary pollinators. To test this, we studied the floral biology, breeding system and floral visitors of this species and the effectiveness of nocturnal and diurnal visitors. Floral biology was defined based on floral morphology, floral cycle and nectar production of the flowers. The breeding system and relative contributions of diurnal and nocturnal visitors to fruit and seed set were analysed through field experiments. E. terscheckii flowers opened at sunset and closed the following day. The peak of nectar production occurred at midnight. Flowers were determined to be self-incompatible. Moths, bees and birds were identified as floral visitors. Moths were the most frequent visitors at night, whereas bees were the most frequent visitors during the day. Fruit production by diurnal pollinators was less than that by nocturnal pollinators; among all floral visitors, moths were the most effective pollinators. We have demonstrated for the first time that moths are the primary pollinators of columnar cacti of the genus Echinopsis. Our results suggest that moths might be important pollinators of columnar cactus species with nocturnal flowers in the extra-tropical deserts of South America.

  10. Diurnal variations in the plasma concentrations of mevalonic acid in patients with abetalipoproteinaemia.

    PubMed

    Pappu, A S; Illingworth, D R

    1994-10-01

    Previous studies have demonstrated that changes in the rates of cholesterol biosynthesis can be evaluated by the determination of plasma concentrations of sterol intermediates, including mevalonic acid and lathosterol and that, in normal human subjects, a diurnal rhythm exists in which the highest concentrations of sterol intermediates are observed at night. The factors responsible for this diurnal rhythm in cholesterol synthesis are, however, unknown. To test the hypothesis that the nocturnal increase in cholesterol biosynthesis is attributable to a reduced rate of hepatic uptake of chylomicron remnants at night as compared to higher rates of uptake during the daytime in response to alimentary lipaemia, we have examined the diurnal rhythm of mevalonic acid in six normal volunteers and three patients with phenotypic abetalipoproteinaemia. The latter patients do not absorb appreciable amounts of dietary cholesterol and are unable to synthesize chylomicron particles. Plasma concentrations of mevalonic acid exhibited a diurnal rhythm in the normal subjects, and the highest plasma concentrations were observed between 24.00 hours/04.00 hours. A similar rhythm was observed in the plasma of patients with abetalipoproteinaemia. These results suggest that the nocturnal increase in cholesterol biosynthesis which occurs in humans is not attributable to reduced hepatic uptake of chylomicron remnants at night; further studies are needed to better define those factors which influence the periodicity of cholesterol biosynthesis in humans.

  11. Diurnal Cortisol Profile in Williams Syndrome in Novel and Familiar Settings

    ERIC Educational Resources Information Center

    Lense, Miriam Diane; Tomarken, Andrew J.; Dykens, Elisabeth M.

    2013-01-01

    Williams syndrome (WS) is a neurodevelopmental genetic disorder associated with high rates of anxiety and social issues. We examined diurnal cortisol, a biomarker of the stress response, in adults with WS in novel and familiar settings, and compared these profiles to typically developing (TD) adults. WS and TD participants had similar profiles in…

  12. Thermoregulatory Behavior in Diurnal Lizards as a Vehicle for Teaching Scientific Process

    ERIC Educational Resources Information Center

    Platz, James E.

    2009-01-01

    Field experiments offer the opportunity for hands on experience with the scientific process. While this is true of a wide variety of activities, many have pitfalls both experimental and logistical that reduce the overall rate of success, in turn, influencing student learning outcomes. Relying on small, territorial, diurnal lizards and an array of…

  13. Approximate analytical solution to diurnal atmospheric boundary-layer growth under well-watered conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The system of governing equations of a simplified slab model of the uniformly-mixed, purely convective, diurnal atmospheric boundary layer (ABL) is shown to allow immediate solutions for the potential temperature and specific humidity as functions of the ABL height and net radiation when expressed i...

  14. Entrainment of the diurnal rhythm of plasma leptin to meal timing.

    PubMed Central

    Schoeller, D A; Cella, L K; Sinha, M K; Caro, J F

    1997-01-01

    To identify the physiologic factor(s) that entrain the diurnal rhythm of plasma leptin, leptin levels were measured hourly after changes in light/dark cycle, sleep/wake cycle, and meal timing. Four young male subjects were studied during each of two protocols, those being a simulated 12-h time zone shift and a 6.5-h meal shift. During the baseline day, plasma leptin demonstrated a strong diurnal rhythm with an amplitude of 21%, zenith at 2400 h, and nadir between 0900 and 1200 h. Acute sleep deprivation did not alter plasma leptin, but day/night reversal (time zone shift) caused a 12+/-2 h shift (P < 0.01) in the timing of the zenith and nadir. When meals were shifted 6.5 h without changing the light or sleep cycles, the plasma leptin rhythm was shifted by 5-7 h (P < 0.01). The phase change occurred rapidly when compared with changes in the diurnal rhythm of cortisol, suggesting that leptin levels are not acutely entrained to the circadian clock. The leptin rhythm was altered by meal timing in a manner very similar to the rhythm of de novo cholesterol synthesis. We conclude that the diurnal rhythm of plasma leptin in young males is entrained to meal timing. PMID:9312190

  15. Diurnal testosterone variability is differentially associated with parenting quality in mothers and fathers.

    PubMed

    Endendijk, Joyce J; Hallers-Haalboom, Elizabeth T; Groeneveld, Marleen G; van Berkel, Sheila R; van der Pol, Lotte D; Bakermans-Kranenburg, Marian J; Mesman, Judi

    2016-04-01

    Previous studies on the relation between testosterone (T) levels and parenting have found ample evidence for the challenge hypothesis, demonstrating that high T levels inhibit parental involvement and that becoming a parent is related to a decrease in T levels in both mothers and fathers. However, less is known about the relation between T levels and more qualitative aspects of parenting. In the current study we examined basal T levels and diurnal variability in T levels in relation to mothers' and fathers' parenting quality. Participants included 217 fathers and 124 mothers with two children (3 and 5years of age). Evening and morning salivary T samples were analyzed with radio-immunoassays to determine circulating T levels. Parental sensitivity (i.e., child-centered responsiveness) and respect for children's autonomy were observed during free play in the family home. The results showed that higher evening T levels in mothers were associated with more sensitivity to the oldest and youngest child. Diurnal T variability was more consistently associated with parenting behavior towards their children than basal T levels. For fathers, more diurnal variability in T was associated with more sensitivity and more respect for autonomy with their youngest children. For mothers, more diurnal variability in T was associated with less sensitivity to both children and less respect for the youngest child's autonomy. These findings suggest that the T system might act differently in relation to parenting behavior in males and females.

  16. Diurnal variability of the global tropical tropopause: results inferred from COSMIC observations

    NASA Astrophysics Data System (ADS)

    Suneeth, K. V.; Das, Siddarth Shankar; Das, Subrata Kumar

    2017-01-01

    Short and long-term variability of the tropical tropopause controls the exchange of minor constituents between the troposphere and the stratosphere. We present the diurnal variability of the global tropical tropopause altitude and temperature using 7 years of COSMIC observations. The aim of the study is to extract diurnal tropopause signals and their impact on stratosphere-troposphere exchange processes. The possible role of atmospheric tides and convection in controlling the tropopause characteristics are discussed. The most significant and new observation is that in the deep tropics the cold-point tropopause altitude is higher and temperatue is cooler over the land (ocean) during evening to late evening hours (afternoon to early evening). Lower tropopause altitude allows the stratospheric air intrusion into the troposphere during the day time. The combined effect of diurnal tropopause altitude changes and turbulent mixing increases the possibility of stratospheric intrusions. A warmer forenoon tropopause allows increased injection of water vapor from the troposphere to the lower stratosphere. Over the tropical land (ocean), the zonal mean diurnal amplitude is 130-200 m (140-180 m) for tropopause altitude and 0.6-0.9 K (0.6-0.8 K) for tropopause temperature.

  17. Gross ecosystem photosynthesis causes a diurnal pattern in methane emission from rice

    NASA Astrophysics Data System (ADS)

    Hatala, Jaclyn A.; Detto, Matteo; Baldocchi, Dennis D.

    2012-03-01

    Understanding the relative contribution of environmental and substrate controls on rice paddy methanogenesis is critical for developing mechanistic models of landscape-scale methane (CH4) flux. A diurnal pattern in observed rice paddy CH4 flux has been attributed to fluctuations in soil temperature physically driving diffusive CH4 transport from the soil to atmosphere. Here we make direct landscape-scale measurements of carbon dioxide and CH4 fluxes and show that gross ecosystem photosynthesis (GEP) is the dominant cause of the diurnal pattern in CH4 flux, even after accounting for the effects of soil temperature. The time series of GEP and CH4 flux show strong spectral coherency throughout the rice growing season at the diurnal timescale, where the peak in GEP leads that of CH4 flux by 1.3 ± 0.08 hours. By applying the method of conditional Granger causality in the spectral domain, we demonstrated that the diurnal pattern in CH4 flux is primarily caused by GEP.

  18. Diurnal change in trees as observed by optical and microwave sensors - The EOS Synergism Study

    NASA Technical Reports Server (NTRS)

    Way, Jobea; Mcdonald, Kyle; Paris, Jack; Dobson, Myron C.; Ulaby, Fawwaz T.; Weber, James A.; Ustin, Susan L.; Vanderbilt, Vern C.; Kasischke, Eric S.

    1991-01-01

    The EOS (Earth Observing System) Synergism Study examined the temporal variability of the optical and microwave backscatter due to diurnal change in canopy properties of interest to ecosystem modelers. The experiment was designed to address diurnal changes in canopy water status that relate to transpiration. Multispectral optical and multifrequency, multipolarization microwave measurements were acquired using boom-truck-based systems over a two-week period. Sensor and canopy properties were collected around the clock. The canopy studied was a walnut orchard in the San Joaquin Valley of California. The results demonstrate a large diurnal variation in the dielectric properties of the tree that in turn produces significant diurnal changes in the microwave backscatter. The results suggest that permanently orbiting spaceborne sensors such as those on EOS should be placed in orbits that are optimized for the individual sensor and need not be tied together by a tight simultaneity requirement on the order of minutes to hours for the purpose of monitoring ecosystem properties.

  19. A DIURNAL REFLECTANCE MODEL USING GRASS: SURFACE-SUBSTRATE INTERACTION AND INVERSE SOLUTION

    EPA Science Inventory

    The accuracy of using remote sensing data from earth orbiting radiometers can be improved by using a model that helps to separate the green-fraction in a canopy reflectance () from thatch and soil background, accounts for their diurnal changes, and inverts to a solution of a biop...

  20. 40 CFR 1060.525 - How do I test fuel systems for diurnal emissions?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... fuel tanks, and volume-compensating air bags. (b) You may subtract your fuel tank's permeation...) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY... diurnal emission standard. (8) For emission control technologies that rely on a sealed fuel system,...

  1. 40 CFR 1060.525 - How do I test fuel systems for diurnal emissions?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... fuel tanks, and volume-compensating air bags. (b) You may subtract your fuel tank's permeation...) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY... diurnal emission standard. (8) For emission control technologies that rely on a sealed fuel system,...

  2. 40 CFR 1060.525 - How do I test fuel systems for diurnal emissions?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... fuel tanks, and volume-compensating air bags. (b) You may subtract your fuel tank's permeation...) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY... diurnal emission standard. (8) For emission control technologies that rely on a sealed fuel system,...

  3. The Diurnal Temperature Cycle and Its Relation to Boundary-Layer Structure During the Morning Transition

    NASA Astrophysics Data System (ADS)

    Ketzler, G.

    2014-05-01

    The morning portion of the near-surface diurnal temperature cycle is analyzed in combination with heat-flux and vertical temperature-gradient data. During summer, mean diurnal cycles of temperature rates-of-change show periods that can be related to defined points of the morning transition (MT). The start of the MT is clearly marked with a temperature discontinuity, apparent even on individual days, while the end of the transition is apparent only when using averages over many days. The findings concerning the timing of the MT using temperature cycle analysis correspond well with studies using heat-flux measurements. Mean diurnal cycles of temperature rates-of-change for stations in different urban and valley positions show differences that can partly be explained by apparent effects of the surroundings. For the valley situation, the timing differences and their relation to station position in the valley are generally plausible, while urban effects on the diurnal cycle are apparent but less distinct, which may be due to the small number of stations used. The results indicate that warming already begins before heat-flux crossover, which is the current definition of the beginning of the MT. This definition should be extended to include the phase between the temperature rate-of-change crossover and heat-flux crossover, which represents the early part of the MT before warming reaches instrument level.

  4. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false What diurnal requirements apply for equipment? 1060.105 Section 1060.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...-system components must meet the following requirements: (1) They must be self-sealing when detached...

  5. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false What diurnal requirements apply for equipment? 1060.105 Section 1060.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...-system components must meet the following requirements: (1) They must be self-sealing when detached...

  6. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false What diurnal requirements apply for equipment? 1060.105 Section 1060.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...-system components must meet the following requirements: (1) They must be self-sealing when detached...

  7. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What diurnal requirements apply for equipment? 1060.105 Section 1060.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...-system components must meet the following requirements: (1) They must be self-sealing (without any...

  8. Impact of diurnal variation in vegetation water content on radar backscatter of maize during water stress

    NASA Astrophysics Data System (ADS)

    van Emmerik, Tim; Steele-Dunne, Susan; Judge, Jasmeet; van de Giesen, Nick

    2014-05-01

    Microwave emission and backscatter of vegetated surfaces are influenced by vegetation water content (VWC), which varies in response to availability of soil moisture in the root zone. Understanding the influence of diurnal VWC dynamics on radar backscatter will improve soil moisture retrievals using microwave remote sensing, and will provide insight into the potential use for radar to directly monitor vegetation water status. The goal of this research is to investigate the effect of diurnal variation in VWC of an agricultural canopy on backscatter for different radar configurations. Water stress was induced in a corn (Zea mays) canopy near Citra, Florida, between September 1 and October 20, 2013. Diurnal destructive samples from the canopy were collected to determine leaf, stalk and total VWC. Water stress was quantified by calculating the evaporation deficit and measuring the soil water tension. The water-cloud model was used to model the influence of VWC and soil moisture variations on backscatter for a range of frequencies, polarizations and incidence angles. Furthermore, radar backscatter time series was simulated to show the effect of water stress on the diurnal variation in backscatter due to VWC. Results of this study show the very significant effects that VWC dynamics have on radar backscatter. We also highlight the potential for vegetation and soil water status monitoring using microwave remote sensing.

  9. Absence of diurnal variation of C-reactive protein concentrations in healthy human subjects

    NASA Technical Reports Server (NTRS)

    Meier-Ewert, H. K.; Ridker, P. M.; Rifai, N.; Price, N.; Dinges, D. F.; Mullington, J. M.

    2001-01-01

    BACKGROUND: The concentration of C-reactive protein (CRP) in otherwise healthy subjects has been shown to predict future risk of myocardial infarction and stroke. CRP is synthesized by the liver in response to interleukin-6, the serum concentration of which is subject to diurnal variation. METHODS: To examine the existence of a time-of-day effect for baseline CRP values, we determined CRP concentrations in hourly blood samples drawn from healthy subjects (10 males, 3 females; age range, 21-35 years) during a baseline day in a controlled environment (8 h of nighttime sleep). RESULTS: Overall CRP concentrations were low, with only three subjects having CRP concentrations >2 mg/L. Comparison of raw data showed stability of CRP concentrations throughout the 24 h studied. When compared with cutoff values of CRP quintile derived from population-based studies, misclassification of greater than one quintile did not occur as a result of diurnal variation in any of the subjects studied. Nonparametric ANOVA comparing different time points showed no significant differences for both raw and z-transformed data. Analysis for rhythmic diurnal variation using a method fitting a cosine curve to the group data was negative. CONCLUSIONS: Our data show that baseline CRP concentrations are not subject to time-of-day variation and thus help to explain why CRP concentrations are a better predictor of vascular risk than interleukin-6. Determination of CRP for cardiovascular risk prediction may be performed without concern for diurnal variation.

  10. Diurnal activities of the brown stink bug (Hemiptera: Pentatomidae) in and near tasseling corn fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The demand for effective management of the brown stink bug, Euschistus servus, in corn and other crops has been increasing in recent years. To identify when and where the stink bugs are most likely to occur for targeted insecticide application, diurnal activities of stink bugs in and near the field...

  11. Sensitivity of diurnal variation in simulated precipitation during East Asian summer monsoon to cumulus parameterization schemes

    NASA Astrophysics Data System (ADS)

    Choi, In-Jin; Jin, Emilia Kyung; Han, Ji-Young; Kim, So-Young; Kwon, Young

    2015-12-01

    The capability to simulate the diurnal variation of precipitation over East Asia region during the summertime of 2011 is investigated using five different cumulus parameterization schemes with the Weather Research and Forecasting model. A semidiurnal cycle with a 12 h interval over land and a diurnal cycle with a 24 h interval over ocean are commonly found in all simulations, consistent with the observed diurnal cycle. Two observed dominant peaks in the early morning and afternoon are reproduced in all simulations. With overestimated precipitation rate, however, the simulated afternoon peaks occur earlier than the observed peaks by 2 h for the Kain-Fritsch (KF) and Simplified Arakawa-Schubert schemes, and by 3 h for the Betts-Miller-Janjić and Tiedtke schemes. The overestimation of simulated precipitation frequency leads to amplitude and phase errors in the precipitation rate, and the early peak time of simulated precipitation intensity intensifies the phase error in the simulation over land. The KF scheme with alternative trigger function (KFtr) based on moisture advection provides slightly better results in terms of alleviating the overestimated precipitation rate and frequency and delaying the afternoon peaks. Additional sensitivity simulations based on the change of temperature perturbation in the trigger function of the KF and KFtr schemes demonstrate the afternoon peak tends to be delayed as temperature perturbation decreases, implying the significant role of convective initiation frequency in determining diurnal peaks of precipitation. Modulation of temperature perturbation alleviates the precipitation frequency bias, while it could not resolve the precipitation intensity bias.

  12. Salivary Biomarker Levels and Diurnal Variation: Associations with Medications Prescribed to Control Children's Problem Behavior

    ERIC Educational Resources Information Center

    Hibel, Leah C.; Granger, Douglas A.; Cicchetti, Dante; Rogosch, Fred

    2007-01-01

    This study examined associations between medications prescribed to control children's problem behaviors and levels of, and diurnal variation in, salivary cortisol (C), testosterone (T), and dehydroepiandrosterone (DHEA). Saliva was collected in the morning, midday, and afternoon from 432 children ages 6-13 years. Relative to a no-medication…

  13. Retinular fine structure in compound eyes of diurnal and nocturnal sphingid moths.

    PubMed

    Eguchi, E

    1982-01-01

    Retinular fine structure has been compared in the superposition compound eyes of three sphingid moths, one nocturnal, Cechenena, and two diurnal, Cephonodes and Macroglossum. Cechenena and Cephonodes have tiered retinas with three kinds of retinular cells: two distal, six regular and one basal. The distal retinular cells in Cechenena are special in having a complex partially intracellular rhabdomere not present in Cephonodes. Macroglossum lacks the distal retinular cell. In Cephonodes a unique rhabdom type, formed by the six regular retinular cells in the middle region of the retinula, is divided into three separate longitudinal plates arranged closely parallel to one another. Their constituent microvilli are consequently all nearly unidirectional. The ratio of rhabdom volume to retinular cell volume in the two diurnal sphingids is 10-27%; this is about the same as that (25%) of skipper butterflies, but significantly smaller than in the nocturnal Cechenena (60%). In the diurnal sphingids retinular cell membranes show elongate meandering profiles with septate junctions between adjacent retinular cells. From the comparative fine structure of their eyes the diurnal sphingids and the skippers would appear to be phylogenetically closely related.

  14. 40 CFR 1045.625 - What requirements apply under the Diurnal Transition Program?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false What requirements apply under the Diurnal Transition Program? 1045.625 Section 1045.625 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION...

  15. 40 CFR 1045.625 - What requirements apply under the Diurnal Transition Program?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false What requirements apply under the Diurnal Transition Program? 1045.625 Section 1045.625 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION...

  16. 40 CFR 1045.625 - What requirements apply under the Diurnal Transition Program?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false What requirements apply under the Diurnal Transition Program? 1045.625 Section 1045.625 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION...

  17. 40 CFR 1045.625 - What requirements apply under the Diurnal Transition Program?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false What requirements apply under the Diurnal Transition Program? 1045.625 Section 1045.625 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION...

  18. Trans-ionospheric pulse pairs (TIPPs): Their occurrence rates and diurnal variation

    NASA Astrophysics Data System (ADS)

    Zuelsdorf, R. S.; Strangeway, R. J.; Russell, C. T.; Franz, R.

    Trans-Ionospheric Pulse Pairs (TIPPs) have been detected by the Blackbeard instrument aboard the ALEXIS spacecraft in the VHF band between 28 and 166 MHz with dispersion indicating a subionospheric source. Using a database that runs from 2 November 1993 to 19 November 1996, the rate and diurnal variation of TIPP detection are calculated for central Africa, Indonesia, and North America. The rate of TIPP detection by Blackbeard in the frequency band from 28-95 MHz is 0.02 and 0.04 TIPPs per second for central Africa and Indonesia respectively. For North America the data were acquired in a narrow band from 28-37.9 MHz and the TIPP detection rate is 0.007 events per second. The diurnal variation of TIPPs resembles the diurnal variation of CG lightning during daylight hours. However the TIPP production remains strong through midnight and into the morning hours, whereas CG flash production tends to decrease more sharply after peaking around 4 PM local time. Thus the diurnal variation suggests that TIPPs are not produced in CG flashes, a conclusion consistent with their correlation with intracloud pulses.

  19. Diurnal Albedo Variations of the Martian North Polar Water Ice Cap

    NASA Technical Reports Server (NTRS)

    Troy, R. F.; Bass, D.

    2002-01-01

    Presentation of findings regarding diurnal variations in the north polar water ice cap of Mars as part of a larger study of the interannual and seasonal variations of the Martian north polar water ice cap. Additional information is contained in the original extended abstract.

  20. A Combined Infrared and Microwave Technique for Studying the Diurnal Variation of Rainfall Over Amazonia

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Xu, L.; Adler, R. F.; Anagnostou, E.; Rickenbach, T. M.

    1999-01-01

    In this paper we present results from the application of a satellite infrared (IR) technique for estimating rainfall over northern South America. Our main objectives are to examine the diurnal variability of rainfall and to investigate the relative contributions from the convective and stratiform components. Additional information is contained in the original.

  1. Diurnal variation of surface ozone in mountainous areas: Case study of Mt. Huang, East China.

    PubMed

    Zhang, Lei; Jin, Lianji; Zhao, Tianliang; Yin, Yan; Zhu, Bin; Shan, Yunpeng; Guo, Xiaomei; Tan, Chenghao; Gao, Jinhui; Wang, Haoliang

    2015-12-15

    To explore the variations in atmospheric environment over mountainous areas, measurements were made from an intensive field observation at the summit of Mt. Huang (30.13°N, 118.15°E, 1841m above sea level), a rural site located in East China, from June to August 2011. The measurements revealed a diurnal change of surface O3 with low concentrations during the daytime and high concentrations during the nighttime. The causes of diurnal O3 variations over the mountain peak in East China were investigated by using a fairly comprehensive WRF-Chem and HYSPLIT4 modeling approach with observational analysis. By varying model inputs and comparing the results to a baseline modeling and actual air quality observations, it is found that nearby ozone urban/anthropogenic emission sources were contributing to a nighttime increase in mountaintop ozone levels due to a regional transport lag and residual layer effects. Positive correlation of measured O3 and CO concentrations suggested that O3 was associated with anthropogenic emissions. Sensitivity modeling experiments indicated that local anthropogenic emissions had little impact on the diurnal pattern of O3. The diurnal pattern of O3 was mainly influenced by regional O3 transport from the surrounding urban areas located 100-150km away from the summit, with a lag time of 10h for transport.

  2. Variability of diurnal tides and planetary waves during November 1978-May 1979

    NASA Astrophysics Data System (ADS)

    Lieberman, R. S.; Oberheide, J.; Hagan, M. E.; Remsberg, E. E.; Gordley, L. L.

    2004-04-01

    Nonlinear interactions between stationary waves and the migrating tides have been proposed as possible sources of nonmigrating tides in the middle and upper atmosphere. The objective of this study is to increase observational support for these processes. We examine the evolution of stationary planetary waves and nonmigrating diurnal tides in the lower mesosphere during November 1978-May 1979, based on a newly released, version 6 of the Nimbus 7 LIMS dataset. Planetary wavenumber one is large and variable during the Northern hemisphere winter months, reaching peak amplitude in the lower mesosphere between 20 and 30 January. This behavior is accompanied by rapid amplification of nonmigrating diurnal tides with zonal wavenumbers zero and two. These components correspond to product waves generated by interaction between the migrating diurnal tide and the stationary wave. The westward traveling zonal wavenumber two diurnal tide is dominant at tropical latitudes, in accordance with theoretical studies. The correlation between the nonmigrating tide and stationary wavenumber one is highest when the stationary wave penetrates to subtropical latitudes.

  3. Diurnal-period currents trapped above Fieberling Guyot: observed characteristics and model comparisons

    USGS Publications Warehouse

    Noble, M.A.; Brink, K.H.; Eriksen, C.C.

    1994-01-01

    Current measurements at depths of 19, 115, 264 and 464 m above the summit of Fieberling Guyot (32??28???N, 127??47???W) for 13 months in 1989 show that the diurnal tides are strongly amplified. The measured variances for K1, P1 and O1 at the 115 m depth were 810, 140 and 80 times larger than the variances of the respective estimated barotropic tides. The diurnal currents closer to the summit were also strongly amplified, through the variance ratios were 40-50% of the ratios observed at 115 m. The diurnal band currents were only amplified at the precise tidal frequencies; the bandwidth of the response was less than 0.0002 cph. The discrete character of the response suggests that only currents with large spatial scales will be amplified. The characteristics of the amplified diurnal currents are compared to those predicted by a model for Fieberling Guyot of seamount-trapped waves driven by the barotropic tide. The amplitudes of the responses at this one site on the seamount compare favourably to the predicted. ?? 1994.

  4. The impact of the diurnal insolation cycle on the tropical cyclone heat engine

    NASA Astrophysics Data System (ADS)

    O'Neill, Morgan E.; Perez-Betancourt, Diamilet; Wing, Allison A.

    A hurricane, or tropical cyclone, is understood as a heat engine that moves heat from the warm sea surface to the cold tropopause. The efficiency of this engine depends in part on the strength and duration of solar heating. Over land, peak rainfall associated with individual thunderstorms occurs in the late afternoon. Over ocean, with its markedly higher surface heat capacity, deep convection responds more to radiational cooling than daytime surface heating. However, the role of daily varying solar forcing on the dynamics of tropical cyclones is poorly understood. Recently, Dunion et al. (2014) reported significant, repeating diurnal behavior propagating outward from tropical cyclone centers, using infrared imagery from nine years of North Atlantic tropical cyclones. We study the impact of the diurnal cycle on tropical cyclones using a high resolution 3D numerical model, the System for Atmospheric Modeling (Khairoutdinov and Randall 2003). Simulations are run with and without variable sunlight. We are able to reproduce the observational finding of Dunion et al. (2014), and further identify a diurnally-varying residual circulation in the tropical cyclone at midlevels. The impact of the diurnal cycle on the equilibrium dynamics of tropical cyclones is also discussed.

  5. Diurnal Radiation Cycle Impact in Different Stages of Hurricane Edouard (2014)

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Tang, X.

    2015-12-01

    This work examines the impact of diurnally varying radiation cycle on the intensity, structure and track of Hurricane Edouard (2014) at different stages of its life cycle through convection-permitting simulations.During the formation stage, nighttime destabilization through radiative cooling may promote deep moist convection that eventually leads to the genesis of the storm while a tropical cyclone fails to develop in the absence of the night phase despite a strong incipient vortex under favorable environmental conditions. The nighttime radiative cooling further enhances the primary vortex before the storm undergoes rapid intensification (RI). Thereafter, the nighttime radiative cooling mainly increases convective activities outside of the primary eyewall that leads to stronger/broader outer rainbands and larger storm size during the mature stage of the hurricane but there is little impact on the hurricane intensity in terms of maximum surface wind speed. There is no apparent eyewall replacement cycle (ERC) simulated in both sensitivity experiments without the diurnal cycle (daytime only and nighttime only) while the control forecast undergoes secondary eyewall formation during the mature stage of Edourad (as observed), suggesting the potential role of the diurnally varying radiative impact. Through changing the strength of the initial vortex during the formation stage, the diurnal cycle may also alter the track of the storm.

  6. Diurnal and seasonal variation of the brain serotonin system in healthy male subjects.

    PubMed

    Matheson, Granville J; Schain, Martin; Almeida, Rita; Lundberg, Johan; Cselényi, Zsolt; Borg, Jacqueline; Varrone, Andrea; Farde, Lars; Cervenka, Simon

    2015-05-15

    The mammalian circadian clock underlies both diurnal and seasonal changes in physiology, and its function is thought to be disturbed in both seasonal and non-seasonal depression. In humans, molecular imaging studies have reported seasonal changes in the serotonin system. Despite the role of the circadian clock in generating seasonal physiological changes, however, diurnal variation of serotonin receptors and transporters has never been directly studied in humans. We used positron emission tomography to examine diurnal and seasonal changes in the serotonin 5-HT1A receptor and serotonin transporter in two large cohorts of healthy male subjects, employing a cross-sectional design. In 56 subjects measured with [(11)C]WAY-100635, we observed diurnal increases in the availability of 5-HT1A receptors in the cortex. In 40 subjects measured with [(11)C]MADAM, a decrease in 5-HTT was observed in the midbrain across the day. We also found seasonal changes in the 5-HT1A receptor in serotonin projection regions, with higher availability on days with a longer duration of daylight. Our observation that serotonin receptor and transporter levels may change across the day in humans is corroborated by experimental research in rodents. These findings have important implications for understanding the relationship between the circadian and serotonin systems in both the healthy brain and in affective disorders, as well as for the design of future molecular imaging studies.

  7. Diurnal sampling reveals significant variation in CO2 emission from a tropical productive lake.

    PubMed

    Reis, P C J; Barbosa, F A R

    2014-08-01

    It is well accepted in the literature that lakes are generally net heterotrophic and supersaturated with CO2 because they receive allochthonous carbon inputs. However, autotrophy and CO2 undersaturation may happen for at least part of the time, especially in productive lakes. Since diurnal scale is particularly important to tropical lakes dynamics, we evaluated diurnal changes in pCO2 and CO2 flux across the air-water interface in a tropical productive lake in southeastern Brazil (Lake Carioca) over two consecutive days. Both pCO2 and CO2 flux were significantly different between day (9:00 to 17:00) and night (21:00 to 5:00) confirming the importance of this scale for CO2 dynamics in tropical lakes. Net heterotrophy and CO2 outgassing from the lake were registered only at night, while significant CO2 emission did not happen during the day. Dissolved oxygen concentration and temperature trends over the diurnal cycle indicated the dependence of CO2 dynamics on lake metabolism (respiration and photosynthesis). This study indicates the importance of considering the diurnal scale when examining CO2 emissions from tropical lakes.

  8. Time to decide: Diurnal variations on the speed and quality of human decisions.

    PubMed

    Leone, María Juliana; Fernandez Slezak, Diego; Golombek, Diego; Sigman, Mariano

    2017-01-01

    Human behavior and physiology exhibit diurnal fluctuations. These rhythms are entrained by light and social cues, with vast individual differences in the phase of entrainment - referred as an individual's chronotype - ranging in a continuum between early larks and late owls. Understanding whether decision-making in real-life situations depends on the relation between time of the day and an individual's diurnal preferences has both practical and theoretical implications. However, answering this question has remained elusive because of the difficulty of measuring precisely the quality of a decision in real-life scenarios. Here we investigate diurnal variations in decision-making as a function of an individual's chronotype capitalizing on a vast repository of human decisions: online chess servers. In a chess game, every player has to make around 40 decisions using a finite time budget and both the time and quality of each decision can be accurately determined. We found reliable diurnal rhythms in activity and decision-making policy. During the morning, players adopt a prevention focus policy (slower and more accurate decisions) which is later modified to a promotion focus (faster but less accurate decisions), without daily changes in performance.

  9. Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

    EPA Science Inventory

    Bidirectional air–surface exchange of ammonia (NH3) has been neglected in many air quality models. In this study, we implement the bidirectional exchange of NH3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH3...

  10. Diurnal Human Activity and Introduced Species Affect Occurrence of Carnivores in a Human-Dominated Landscape.

    PubMed

    Moreira-Arce, Dario; Vergara, Pablo M; Boutin, Stan

    2015-01-01

    Diurnal human activity and domestic dogs in agro-forestry mosaics should theoretically modify the diurnal habitat use patterns of native carnivores, with these effects being scale-dependent. We combined intensive camera trapping data with Bayesian occurrence probability models to evaluate both diurnal and nocturnal patterns of space use by carnivores in a mosaic of land-use types in southern Chile. A total of eight carnivores species were recorded, including human-introduced dogs. During the day the most frequently detected species were the culpeo fox and the cougar. Conversely, during the night, the kodkod and chilla fox were the most detected species. The best supported models showed that native carnivores responded differently to landscape attributes and dogs depending on both the time of day as well as the spatial scale of landscape attributes. The positive effect of native forest cover at 250 m and 500 m radius buffers was stronger during the night for the Darwin's fox and cougar. Road density at 250 m scale negatively affected the diurnal occurrence of Darwin´s fox, whereas at 500 m scale roads had a stronger negative effect on the diurnal occurrence of Darwin´s foxes and cougars. A positive effect of road density on dog occurrence was evidenced during both night and day. Patch size had a positive effect on cougar occurrence during night whereas it affected negatively the occurrence of culpeo foxes and skunks during day. Dog occurrence had a negative effect on Darwin's fox occurrence during day-time and night-time, whereas its negative effect on the occurrence of cougar was evidenced only during day-time. Carnivore occurrences were not influenced by the proximity to a conservation area. Our results provided support for the hypothesis that diurnal changes to carnivore occurrence were associated with human and dog activity. Landscape planning in our study area should be focused in reducing both the levels of diurnal human activity in native forest remnants

  11. Diurnal Human Activity and Introduced Species Affect Occurrence of Carnivores in a Human-Dominated Landscape

    PubMed Central

    Moreira-Arce, Dario; Vergara, Pablo M.; Boutin, Stan

    2015-01-01

    Diurnal human activity and domestic dogs in agro-forestry mosaics should theoretically modify the diurnal habitat use patterns of native carnivores, with these effects being scale-dependent. We combined intensive camera trapping data with Bayesian occurrence probability models to evaluate both diurnal and nocturnal patterns of space use by carnivores in a mosaic of land-use types in southern Chile. A total of eight carnivores species were recorded, including human-introduced dogs. During the day the most frequently detected species were the culpeo fox and the cougar. Conversely, during the night, the kodkod and chilla fox were the most detected species. The best supported models showed that native carnivores responded differently to landscape attributes and dogs depending on both the time of day as well as the spatial scale of landscape attributes. The positive effect of native forest cover at 250m and 500 m radius buffers was stronger during the night for the Darwin's fox and cougar. Road density at 250m scale negatively affected the diurnal occurrence of Darwin´s fox, whereas at 500m scale roads had a stronger negative effect on the diurnal occurrence of Darwin´s foxes and cougars. A positive effect of road density on dog occurrence was evidenced during both night and day. Patch size had a positive effect on cougar occurrence during night whereas it affected negatively the occurrence of culpeo foxes and skunks during day. Dog occurrence had a negative effect on Darwin's fox occurrence during day-time and night-time, whereas its negative effect on the occurrence of cougar was evidenced only during day-time. Carnivore occurrences were not influenced by the proximity to a conservation area. Our results provided support for the hypothesis that diurnal changes to carnivore occurrence were associated with human and dog activity. Landscape planning in our study area should be focused in reducing both the levels of diurnal human activity in native forest remnants and

  12. Diurnal Cycle Variability of Rainfall Over the Indian Region: Perspectives From the TRMM Satellite

    NASA Astrophysics Data System (ADS)

    Sahany, S.; Venugopal, V.; Nanjundiah, R. S.

    2008-12-01

    Using the TRMM 3-hourly, 0.25x0.25 degree 3B42 rainfall product for nine years (1999-2007), we characterise the summer season (JJAS) diurnal cycle of rainfall over the Indian land and its neighbouring oceans (10S to 35N, 60E to 100E). Most previous studies have provided an analysis of a single or few years of satellite- or station-based rainfall data (e.g., Basu, 2007; Yang and Smith, 2006; Nesbitt and Zipser, 2003) and, to our knowledge, this is one of the first studies that aims to exhaustively characterise the diurnal scale statistical characteristics of rainfall over the Indian and surrounding regions. Using harmonic analysis, we extract, at each grid point, every year, the signal corresponding to time periods smaller than 1 day, i.e., the signal that relates to diurnal and sub-diurnal variability. Subsequently, the time of rainfall peak for this filtered signal, referred to as the "peak hour," is estimated, with care taken to eliminate spurious peaks arising out of Gibbs oscillations. Our analysis suggests that the mode of the peak hour (of the diurnal-scale rainfall) over a significant part of Indian land is at 12 UTC (i.e. 5:30PM local time), a finding similar to that reported in previous studies (e.g., Liu and Zipser, 2008; Krishnamurti and Kishtawal, 2000). The Himalayan foothills were found to have a mode of peak hour at 21 UTC (i.e. 2:30AM local time), whereas over the Burmese mountains the rainfall peaks at 9 to 12 UTC (i.e. 3:30 PM to 6:30 PM local time). In addition, over the Bay of Bengal, there is a stratified spatial structure of mode of the peak hour of diurnal rainfall at 6, 9 and 12 UTC from North central to South Bay. This finding, not reported before, could be seen to be consistent with southward propagation of the diurnal rainfall pattern (e.g., Hoyos and Webster, 2007; Zuidema, 2003). We also find that the Arabian sea (to the east of 65E and north of the Equator, along a region where it rains for more than 50% of the time) shows a peak hour

  13. Dysregulation of the cortisol diurnal rhythm following prenatal alcohol exposure and early life adversity

    PubMed Central

    McLachlan, Kaitlyn; Rasmussen, Carmen; Oberlander, Tim F.; Loock, Christine; Pei, Jacqueline; Andrew, Gail; Reynolds, James; Weinberg, Joanne

    2016-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis is impacted by a multitude of pre- and postnatal factors. Developmental programming of HPA axis function by prenatal alcohol exposure (PAE) has been demonstrated in animal models and in human infants, but remains understudied in older children and adolescents. Moreover, early life adversity (ELA), which occurs at higher rates in children with PAE than in non-exposed children, may also play a role in programming the HPA or stress response system. In a cohort of children and adolescents with PAE and ELA (PAE + ELA), we evaluated HPA function through assessment of diurnal cortisol activity compared to that in typically developing controls, as well as the associations among specific ELAs, adverse outcomes, protective factors, and diurnal cortisol. Morning and evening saliva samples were taken under basal conditions from 42 children and adolescents (5–18 years) with PAE + ELA and 43 typically developing controls. High rates of ELA were shown among children with PAE, and significantly higher evening cortisol levels and a flatter diurnal slope were observed in children with PAE + ELA, compared to controls. Medication use in the PAE + ELA group was associated with lower morning cortisol levels, which were comparable to controls. Complex associations were found among diurnal cortisol patterns in the PAE + ELA group and a number of ELAs and later adverse outcomes, whereas protective factors were associated with more typical diurnal rhythms. These results complement findings from research on human infants and animal models showing dysregulated HPA function following PAE, lending weight to the suggestion that PAE and ELA may interact to sensitize the developing HPA axis. The presence of protective factors may buffer altered cortisol regulation, underscoring the importance of early assessment and interventions for children with FASD, and in particular, for the many children with FASD who also have ELA. PMID:27286932

  14. Dysregulation of the cortisol diurnal rhythm following prenatal alcohol exposure and early life adversity.

    PubMed

    McLachlan, Kaitlyn; Rasmussen, Carmen; Oberlander, Tim F; Loock, Christine; Pei, Jacqueline; Andrew, Gail; Reynolds, James; Weinberg, Joanne

    2016-06-01

    The hypothalamic-pituitary-adrenal (HPA) axis is impacted by a multitude of pre- and postnatal factors. Developmental programming of HPA axis function by prenatal alcohol exposure (PAE) has been demonstrated in animal models and in human infants, but remains understudied in older children and adolescents. Moreover, early life adversity (ELA), which occurs at higher rates in children with PAE than in non-exposed children, may also play a role in programming the stress response system. In a cohort of children and adolescents with PAE and ELA (PAE + ELA), we evaluated HPA function through assessment of diurnal cortisol activity compared to that in typically developing controls, as well as the associations among specific ELAs, adverse outcomes, protective factors, and diurnal cortisol. Morning and evening saliva samples were taken under basal conditions from 42 children and adolescents (5-18 years) with PAE + ELA and 43 typically developing controls. High rates of ELA were shown among children with PAE, and significantly higher evening cortisol levels and a flatter diurnal slope were observed in children with PAE + ELA, compared to controls. Medication use in the PAE + ELA group was associated with lower morning cortisol levels, which were comparable to controls. Complex associations were found among diurnal cortisol patterns in the PAE + ELA group and a number of ELAs and later adverse outcomes, whereas protective factors were associated with more typical diurnal rhythms. These results complement findings from research on human infants and animal models showing dysregulated HPA function following PAE, lending weight to the suggestion that PAE and ELA may interact to sensitize the developing HPA axis. The presence of protective factors may buffer altered cortisol regulation, underscoring the importance of early assessment and interventions for children with FASD, and in particular, for the many children with FASD who also have ELA.

  15. Development of a variational data assimilation system for the diurnal cycle of sea surface temperature

    NASA Astrophysics Data System (ADS)

    While, J.; Martin, M.

    2013-06-01

    A variational data assimilation system based on an incremental 4D-Var approach is proposed for use with a zero-dimensional model of the diurnal cycle of sea surface temperature (SST). Traditional 4D-Var, which seeks to find the initial state of a system, is not appropriate for diurnal SST which is a wind and heat flux driven system that has only a limited memory of its prior state. Instead the proposed assimilation system corrects both the initial SST and the heat and wind fluxes applied throughout the day. The assimilation system is tested using ensembles in a set of idealized twin experiments. In these tests controlling parameters are varied around reasonable "default" values with the quality of the analyses assessed against a known "truth". Within our tests data assimilation is shown to improve diurnal SST under most circumstances. Analyzed heat fluxes are also sometimes improved, although the improvement is much less than that observed for diurnal SST. The system was not found to improve the wind stress. The only circumstances where diurnal SST was not found to be improved by the assimilation were where either observational errors were large (greater than 0.5 K in our tests), or biases in the observations were too big (less than -0.3 K or greater than 0.2 K). The non-Gaussian behavior of the wind stress was found to have an impact on the assimilation in low-wind conditions and under these conditions the best analyses were obtained by artificially inflating the observation error.

  16. Removing Diurnal Cycle Contamination in Satellite-Derived Tropospheric Temperatures: Understanding Tropical Tropospheric Trend Discrepancies

    NASA Astrophysics Data System (ADS)

    Po-Chedley, S.; Thorsen, T. J.; Fu, Q.

    2014-12-01

    Tropical mid-tropospheric temperature (TMT) time series have been constructed by several independent research teams using satellite microwave sounding unit (MSU) measurements beginning in 1978 and advanced MSU (AMSU) measurements since 1998. Despite careful efforts to homogenize the MSU/AMSU measurements, tropical TMT trends disagree by a factor of three even though each analysis uses the same basic data. Previous studies suggest that the discrepancy in tropical TMT temperature trends is largely caused by differences in both the NOAA-9 warm target factor and diurnal drift corrections used by various teams to homogenize the MSU/AMSU measurements. This work introduces a new observationally-based method for removing biases related to satellite diurnal drift. The method relies on minimizing inter-satellite and inter-node drifts by subtracting out a common diurnal cycle determined via linear regression. It is demonstrated that this method is effective at removing intersatellite biases and biases between the ascending (PM) and descending (AM) node of individual satellites in the TMT time series. After TMT bias correction, the ratio of tropical tropospheric temperature trends relative to surface temperature trends is in accord with the ratio from global climate models. It is shown that bias corrections for diurnal drift based on a climate model produce tropical trends very similar to those from the observationally-based correction, with a trend differences smaller than 0.02 K decade-1. Differences among various TMT datasets are explored further. Tropical trends from this work are comparable to those from the Remote Sensing System (RSS) and NOAA datasets despite small differences. Larger differences between this work and UAH are attributed to differences in the treatment of the NOAA-9 target factor and the UAH diurnal cycle correction.

  17. Dysregulated diurnal cortisol pattern is associated with glucocorticoid resistance in women with major depressive disorder.

    PubMed

    Jarcho, Michael R; Slavich, George M; Tylova-Stein, Hana; Wolkowitz, Owen M; Burke, Heather M

    2013-04-01

    Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is believed to play a role in the pathophysiology of depression. To investigate mechanisms that may underlie this effect, we examined several indices of HPA axis function - specifically, diurnal cortisol slope, cortisol awakening response, and suppression of cortisol release following dexamethasone administration - in 26 pre-menopausal depressed women and 23 never depressed women who were matched for age and body mass index. Salivary cortisol samples were collected at waking, 30 min after waking, and at bedtime over three consecutive days. On the third day, immediately after the bedtime sample, participants ingested a 0.5mg dexamethasone tablet; they then collected cortisol samples at waking and 30 min after waking the following morning. As predicted, depressed women exhibited flatter diurnal cortisol rhythms and more impaired suppression of cortisol following dexamethasone administration than non-depressed women over the three sampling days. In addition, flatter diurnal cortisol slopes were associated with reduced cortisol response to dexamethasone treatment, both for all women and for depressed women when considered separately. Finally, greater self-reported depression severity was associated with flatter diurnal cortisol slopes and with less dexamethasone-related cortisol suppression for depressed women. Depression in women thus appears to be characterized by altered HPA axis functioning, as indexed by flatter diurnal cortisol slopes and an associated impaired sensitivity of cortisol to dexamethasone. Given that altered HPA axis functioning has been implicated in several somatic conditions, the present findings may be relevant for understanding the pathophysiology of both depression and depression-related physical disease.

  18. The Effects of the Diurnal Atmospheric Variability on Entry, Descent and Landing on Mars

    NASA Astrophysics Data System (ADS)

    Marceta, D.

    2014-12-01

    Landing on Mars is extremely challenging task due to the fact that the Martian atmosphere is the most hostile environment in the Solar system to perform the entry, descent and landing (EDL) process, because it is thick enough to create substantial heating of the entry vehicle but not thick enough to reduce its velocity to the one necessary for safe landing. Beside this, the atmosphere is very dynamic mainly due to high eccentricity of the Martian orbit, obliquity of the orbital to the equatorial plane and close alignment of the winter solstice and the orbital perihelion. Although seasonal variations of atmospheric parameters are significantly larger than the diurnal, it is very important to analyze diurnal cycles as they can significantly change vertical and horizontal atmospheric profiles in very short time intervals. This can present a serious threat to missions which have very precise timings and specific requirements such as the requirement for the daytime landing to enable ground images acquisition during the descent and landing phase. A 3-degrees-of-freedom trajectory integration routine was combined with the Mars Global Reference Atmospheric Model (Mars-GRAM) to identify the dependence of the EDL profiles on the diurnal cycles of atmospheric parameters throughout the Martian year. The obtained results show that the influence of the diurnal cycles is the largest at the equator and decreases relatively symmetrically towards the poles with a slightly stronger influence in the northern hemisphere. Also, there is a significant influence of the orbital position of Mars on the effect of diurnal atmospheric variations which causes that, around the orbital perihelion and winter solstice, there is some kind of inversion of the dependance of optimal entry timing on latitude of the landing site comparing to the rest of the Martian year.

  19. Acute and chronic psychostimulant treatment modulates the diurnal rhythm activity pattern of WKY female adolescent rats.

    PubMed

    Jones, Cathleen G; Yang, Pamela B; Wilcox, Victor T; Burau, Keith D; Dafny, Nachum

    2014-05-01

    The psychostimulants considered the gold standard in the treatment of attention deficit hyperactivity disorder, one of the most common childhood disorders, are also finding their way into the hands of healthy young adults as brain augmentation to improve cognitive performance. The possible long-term effects of psychostimulant exposure in adolescence are considered controversial, and thus, the objective of this study was to investigate whether the chronic exposure to the psychostimulant amphetamine affects the behavioral diurnal rhythm activity patterns of female adolescent Wistar-Kyoto (WKY) rat. The hypothesis of this study is that change in diurnal rhythm activity pattern is an indicator for the long-term effect of the treatment. Twenty-four rats were divided into two groups, control (N = 12) and experimental (N = 12), and kept in a 12:12-h light/dark cycle in an open-field cage. After 5-7 days of acclimation, 11 days of consecutive non-stop behavioral recordings began. On experimental day 1 (ED1), all groups were given an injection of saline. On ED2 to ED7, the experimental group was injected with 0.6 mg/kg amphetamine followed by 3 days of washout from ED8 to ED10, and amphetamine re-challenge on ED11 similar to ED2. The locomotor movements were counted by the computerized animal activity monitoring system, and the cosinor statistical test analysis was used to fit a 24-h curve of the control recording to the activity pattern after treatment. The horizontal activity, total distance, number of stereotypy, vertical activity, and stereotypical movements were analyzed to find out whether the diurnal rhythm activity patterns were altered. Data obtained using these locomotor indices of diurnal rhythm activity pattern suggest that amphetamine treatment significantly modulates the locomotor diurnal rhythm activity pattern of female WKY adolescent rats.

  20. Evaluating Diurnal Variations of Summer Precipitation over the Asian Monsoon Region based on TRMM Satellite Data and Coupled model outputs

    NASA Astrophysics Data System (ADS)

    Mao, J.; Wu, G.

    2013-12-01

    Climatological characteristics of diurnal variations in summer precipitation over the entire Asian monsoon region are comprehensively investigated based on the Tropical Rainfall Measuring Mission (TRMM) satellite data during 1998-2008. The amplitude and phase of diurnal precipitation show a distinct geographical pattern. Significant diurnal variations occur over most of continental and coastal areas including the Maritime Continent, with the relative amplitude exceeding 40%, indicating that the precipitation peak is 1.4 times the 24-h mean. Although the diurnal variations of summer precipitation over the continental areas are characterized by an afternoon peak (1500-1800 Local Solar Time (LST)), over the central Indochina Peninsula and central and southern Indian Peninsula the diurnal phase is delayed to after 2100 LST, suggesting the diurnal behaviors over these areas different from the general continental areas. The weak diurnal variations with relative amplitudes less than 40% exist mainly over oceanic areas in the western Pacific and most of Indian Ocean, with the rainfall peak mainly occurring from midnight to early morning (0000-0600 LST), indicating a typical oceanic regime characterized by an early morning peak. However, apparent exceptions occur over the South China Sea (SCS), Bay of Bengal (BOB), and eastern Arabian Sea, with the rainfall peak occurring in daytime (0900-1500 LST). Prominent meridional propagations of the diurnal phase exist in South Asia and East Asia. The diurnal precipitation variations are also evaluated using the simulated outputs from several coupled general circulation models (CGCMs) participating in CMIP3 (such as CNRM-CM3 and MRI-GCGM2.3.2) and CMIP5 (FGOALS-g2). As compared with those from TRMM data, current state-of-the-art CGCMs still have significant problems in simulating the diurnal variability of the Asian summer monsoon. Although most models can capture the amplitude and phase of the diurnal rainfall cycle over continental

  1. Effect of programmed diurnal temperature cycles on plasma thyroxine level, body temperature, and feed intake of holstein dairy cows

    NASA Astrophysics Data System (ADS)

    Scott, I. M.; Johnson, H. D.; Hahn, G. L.

    1983-03-01

    Holstein cows exposed to simulated summer diurnal ambient temperature cycles of Phoenix, Arizona and Atlanta, Georgia and diurnal modifications of these climates displayed daily cycles fluctuations in plasma thyroxine (T4) and rectal temperatures (Tre). There were daily diurnal changes in T4 and Tre under all simulated climate conditions. Maximal values generally occurred in the evening hours and minimum values in the morning. Although the diurnal rhythm was influenced by the various simulated climates (diurnal modifications) a diurnal rhythm was very evident even under constant conditions at thermoneutral (Tnc) and at cyclic thermoneutral conditions (TN). The major significance of the study is that the initiation of night cooling of the animals at a time when their Tre was highest was most beneficial to maintenance of a TN plasma T4 level. There was a highly significant negative relationship of average T4 and average Tre. There was also a significant negative relationship of feed consumption and average temperature-humidity index (THI). These data suggest that night cooling may be a most effective method to alleviate thermoregulatory limitations of a hot climate on optimal animal performance. Decreasing the night time air temperature (Ta) or THI or increasing the diurnal range allows the cows to more easily dissipate excess body heat accumulated during the day and minimize the thermal inhibition on feed intake, and alterations in plasma T4 and Tre.

  2. Diurnal variations and source apportionment of ozone at the summit of Mount Huang, a rural site in Eastern China.

    PubMed

    Gao, J; Zhu, B; Xiao, H; Kang, H; Hou, X; Yin, Y; Zhang, L; Miao, Q

    2017-03-01

    Comprehensive measurements were conducted at the summit of Mount (Mt.) Huang, a rural site located in eastern China during the summer of 2011. They observed that ozone showed pronounced diurnal variations with high concentrations at night and low values during daytime. The Weather Research and Forecasting with Chemistry (WRF-Chem) model was applied to simulate the ozone concentrations at Mt. Huang in June 2011. With processes analysis and online ozone tagging method we coupled into the model system, the causes of this diurnal pattern and the contributions from different source regions were investigated. Our results showed that boundary layer diurnal cycle played an important role in driving the ozone diurnal variation. Further analysis showed that the negative contribution of vertical mixing was significant, resulting in the ozone decrease during the daytime. In contrast, ozone increased at night owing to the significant positive contribution of advection. This shifting of major factor between vertical mixing and advection formed this diurnal variation. Ozone source apportionment results indicated that approximately half was provided by inflow effect of ozone from outside the model domain (O3-INFLOW) and the other half was formed by ozone precursors (O3-PBL) emitted in eastern, central, and southern China. In the O3-PBL, 3.0% of the ozone was from Mt. Huang reflecting the small local contribution (O3-LOC) and the non-local contributions (O3-NLOC) accounted for 41.6%, in which ozone from the southerly regions contributed significantly, for example, 9.9% of the ozone originating from Jiangxi, representing the highest geographical contributor. Because the origin and variation of O3-NLOC was highly related to the diurnal movements in boundary layer, the similar diurnal patterns between O3-NLOC and total ozone both indicated the direct influence of O3-NLOC and the importance of boundary layer diurnal variations in the formation of such distinct diurnal ozone variations

  3. Diurnal Wind Regimes and Lapse-Rate Variability Over Clean and Debris-Covered Ice

    NASA Astrophysics Data System (ADS)

    Flowers, G. E.; Young, E.

    2015-12-01

    Near-surface winds and air temperature play an important role in the surface energy balance of glaciers and ice sheets, and can be highly variable in space and time. The increasing fraction of debris-covered ice observed in many retreating alpine glacier environments motivates the study of these variables, and the processes that control them, over both clean and debris-covered ice. We use meteorological data collected in the ablation zone of a ~ 5km-long valley glacier in Yukon, Canada, to analyze the diurnal variability of temperature and wind regimes over debris-covered and debris-free ice. Our data reveal pronounced diurnal cycles in temperature lapse rates, wind speeds, and wind directions. Common to both clean and debris-covered areas are: (1) a shallowing of lapse rates in the early morning from 6:00 to 9:00 and a steepening of lapse rates during the day from 9:00 to 16:00, (2) nearly identical lapse rates regardless of surface type between 15:00 and 19:00, and (3) a persistent diurnal wind regime in which up-valley winds occur from late morning to evening, peaking at 16:00-17:00, and relatively weaker down-valley winds occur overnight. Significant differences between the clean-ice and debris-covered sites are also evident in the data, namely: (1) much steeper night-time lapse rates over debris-covered ice than clean ice, (2) the occurrence of steepest lapse rates overnight for debris-covered ice and in late afternoon (around 16:00) for clean ice, and (3) a more pronounced diurnal cycle in windspeed over debris-covered ice than clean ice, despite all stations exhibiting evidence of the diurnal changes in wind direction. The patterns described above conform to a model of weak katabatic flow at night and relatively stronger up-valley winds during the day, peaking in late afternoon. Though absolute temperatures over clean and debris-covered ice are markedly different during the day, lapse rates over both surfaces evolve similarly through the day to achieve steep

  4. Diurnal warming in shallow coastal seas: Observations from the Caribbean and Great Barrier Reef regions

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Minnett, P. J.; Berkelmans, R.; Hendee, J.; Manfrino, C.

    2014-07-01

    A good understanding of diurnal warming in the upper ocean is important for the validation of satellite-derived sea surface temperature (SST) against in-situ buoy data and for merging satellite SSTs taken at different times of the same day. For shallow coastal regions, better understanding of diurnal heating could also help improve monitoring and prediction of ecosystem health, such as coral reef bleaching. Compared to its open ocean counterpart which has been studied extensively and modeled with good success, coastal diurnal warming has complicating localized characteristics, including coastline geometry, bathymetry, water types, tidal and wave mixing. Our goal is to characterize coastal diurnal warming using two extensive in-situ temperature and weather datasets from the Caribbean and Great Barrier Reef (GBR), Australia. Results showed clear daily warming patterns in most stations from both datasets. For the three Caribbean stations where solar radiation is the main cause of daily warming, the mean diurnal warming amplitudes were about 0.4 K at depths of 4-7 m and 0.6-0.7 K at shallower depths of 1-2 m; the largest warming value was 2.1 K. For coral top temperatures of the GBR, 20% of days had warming amplitudes >1 K, with the largest >4 K. The bottom warming at shallower sites has higher daily maximum temperatures and lower daily minimum temperatures than deeper sites nearby. The averaged daily warming amplitudes were shown to be closely related to daily average wind speed and maximum insolation, as found in the open ocean. Diurnal heating also depends on local features including water depth, location on different sections of the reef (reef flat vs. reef slope), the relative distance from the barrier reef chain (coast vs. lagoon stations vs. inner barrier reef sites vs. outer rim sites); and the proximity to the tidal inlets. In addition, the influence of tides on daily temperature changes and its relative importance compared to solar radiation was quantified by

  5. A diurnal animation of thermal images from a day-night pair

    USGS Publications Warehouse

    Watson, K.

    2000-01-01

    Interpretation of thermal images is often complicated because the physical property information is contained in both the spatial and temporal variations of the data and thermal models are necessary to extract and display this information. A linearized radiative transfer solution to the surface flux has been used to derive a function that is invariant with respect to thermal inertia. This relationship makes it possible to predict the temperature variation at any time in the diurnal cycle using only two distinct measurements (e.g., noon and midnight). An animation can then be constructed from a pair of day-night images to view both the spatial and temporal temperature changes throughout the diurnal cycle. A more complete solution for the invariant function, using the method of Laplace transforms and based on the linearized solution, was introduced. These results indicate that the linear model does not provide a sufficiently accurate estimate. Using standard conditions (latitude 30??, solar declination 0??, acquisition times at noon and midnight), this new relationship was used to predict temperature throughout the diurnal cycle to an rms error of 0.2??C, which is close to the system noise of most thermal scanners. The method was further extended to include the primary effects of topographic slope with similar accuracy. The temperature was computed at 48 equally spaced times in the diurnal cycle with this algorithm using a co-registered day and night TIMS (Thermal Infrared Multispectral Scanner) data pair (330 pixels, 450 lilies) acquired of the Carlin, Nevada, area and a co-registered DEM (Digital Elevation Model). (Any reader can view the results by downloading the animation file from an identified tip site). The results illustrate the power of animation to display subtle temporal and spatial temperature changes, which can provide clues to structural controls and material property differences. This 'visual change' approach could significantly increase the use of

  6. Sexual orientation and diurnal cortisol patterns in a cohort of U.S. young adults.

    PubMed

    Austin, S Bryn; Rosario, Margaret; McLaughlin, Katie A; Roberts, Andrea L; Gordon, Allegra R; Sarda, Vishnudas; Missmer, Stacey; Anatale-Tardiff, Laura; Scherer, Emily A

    2016-07-01

    Sexual minorities in the United States are at elevated risk of bullying, discrimination, and violence victimization, all stressors that have been linked to psychological and behavioral stress responses including depressive and anxious symptoms and substance use. Acute and chronic stressors may also elicit physiologic stress responses, including changes in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Few studies, however, have examined the relationship between minority sexual orientation and diurnal cortisol patterns. The present study included 1670 young adults ages 18-32 years (69% female, 31% male) from the Growing Up Today Study, a prospective cohort of U.S. youth. Participants provided five saliva samples over one day to estimate diurnal cortisol patterns. Sexual orientation groups included: completely heterosexual with no same-sex partners (referent), completely heterosexual with same-sex partners/mostly heterosexual, and gay/lesbian/bisexual. Covariates included perceived stress and stressful life events in the past month. Sex-stratified multilevel models of log-transformed cortisol values were used to model diurnal cortisol patterns, and generalized estimating equations were used to model area under the curve (AUC), both with respect to ground (AUCg) and increase (AUCi). Among females, sexual minorities reported significantly more stressful life events in the past month than their heterosexual counterparts. In adjusted multilevel models, sexual orientation was not significantly associated with diurnal cortisol patterns or with AUCg or AUCi in either females or males. There were no significant interactions between sexual orientation and stressful life events. Time-varying negative mood was significantly associated with higher cortisol levels across the day for both female and male participants, after adjusting for all covariates. This study from a large cohort of U.S. young adults did not detect a relationship between sexual

  7. Photoperiod affects the diurnal rhythm of hippocampal neuronal morphology of Siberian hamsters.

    PubMed

    Ikeno, Tomoko; Weil, Zachary M; Nelson, Randy J

    2013-11-01

    Individuals of many species can regulate their physiology, morphology, and behavior in response to annual changes of day length (photoperiod). In mammals, the photoperiodic signal is mediated by a change in the duration of melatonin, leading to alterations in gene expressions, neuronal circuits, and hormonal secretion. The hippocampus is one of the most plastic structures in the adult brain and hippocampal neuronal morphology displays photoperiod-induced differences. Because the hippocampus is important for emotional and cognitive behaviors, photoperiod-driven remodeling of hippocampal neurons is implicated in seasonal differences of affect, including seasonal affective disorder (SAD) in humans. Because neuronal architecture is also affected by the day-night cycle in several brain areas, we hypothesized that hippocampal neuronal morphology would display a diurnal rhythm and that day length would influence that rhythm. In the present study, we examined diurnal and seasonal differences in hippocampal neuronal morphology, as well as mRNA expression of the neurotrophic factors (i.e., brain-derived neurotrophic factor [Bdnf], tropomyosin receptor kinase B [trkB; a receptor for BDNF], and vascular endothelial growth factor [Vegf]) and a circadian clock gene, Bmal1, in the hippocampus of Siberian hamsters. Diurnal rhythms in total length of dendrites, the number of primary dendrites, dendritic complexity, and distance of the furthest intersection from the cell body were observed only in long-day animals; however, diurnal rhythms in the number of branch points and mean length of segments were observed only in short-day animals. Spine density of dendrites displayed diurnal rhythmicity with different peak times between the CA1 and DG subregions and between long and short days. These results indicate that photoperiod affects daily morphological changes of hippocampal neurons and the daily rhythm of spine density, suggesting the possibility that photoperiod-induced adjustments

  8. Sexual orientation and diurnal cortisol patterns in a cohort of U.S. young adults

    PubMed Central

    Austin, S. Bryn; Rosario, Margaret; McLaughlin, Katie A.; Roberts, Andrea L.; Gordon, Allegra R.; Sarda, Vishnudas; Missmer, Stacey; Anatale-Tardiff, Laura; Scherer, Emily A.

    2016-01-01

    Sexual minorities in the United States are at elevated risk of bullying, discrimination, and violence victimization, all stressors that have been linked to psychological and behavioral stress responses including depressive and anxious symptoms and substance use. Acute and chronic stressors may also elicit physiologic stress responses, including changes in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Few studies, however, have examined the relationship between minority sexual orientation and diurnal cortisol patterns. The present study included 1670 young adults ages 18–32 years (69% female, 31% male) from the Growing Up Today Study, a prospective cohort of U.S. youth. Participants provided five saliva samples over one day to estimate diurnal cortisol patterns. Sexual orientation groups included: completely heterosexual with no same-sex partners (referent), completely heterosexual with same-sex partners/mostly heterosexual, and gay/lesbian/bisexual. Covariates included perceived stress and stressful life events in the past month. Sex-stratified multilevel models of log-transformed cortisol values were used to model diurnal cortisol patterns, and generalized estimating equations were used to model area under the curve (AUC), both with respect to ground (AUCg) and increase (AUCi). Among females, sexual minorities reported significantly more stressful life events in the past month than their heterosexual counterparts. In adjusted multilevel models, sexual orientation was not significantly associated with diurnal cortisol patterns or with AUCg or AUCi in either females or males. There were no significant interactions between sexual orientation and stressful life events. Time-varying negative mood was significantly associated with higher cortisol levels across the day for both female and male participants, after adjusting for all covariates. This study from a large cohort of U.S. young adults did not detect a relationship between sexual

  9. Diurnal Variability in the Martian Atmosphere Inferred from Nearly Coincident Profiles at Semidiurnal Separation

    NASA Astrophysics Data System (ADS)

    Heavens, N. G.; Johnson, M. S.

    2013-12-01

    Long-term monitoring of the Martian atmosphere by mapping instruments on sun-synchronous polar orbiters with slight orbital inclinations has two underutilized advantages for studying diurnal variability in atmospheric structure. First, the orbital pattern implies that the nightside orbit will be followed ~ 12 hours later by a dayside orbit that intersects it. That dayside orbit will be followed by a nightside orbit that itself intersects the dayside orbit ~ 12 hours previously at another point. These intersection points mostly occur in the tropics. At the poles, orbit convergence produces a similar effect, such that these semidiurnally separated orbits will have a number of nearly coincident observations in space that sample diurnal change in time. For limb sounders like the Mars Climate Sounder on Mars Reconnaissance Orbiter (MRO-MCS), the horizontal resolution of the instrument at the limb may be comparable to the spatial separation between portions of sequentially intersecting dayside/nightside orbits. Indeed, this width (if simultaneously iterated) would resolve wavenumber 100 structures at the Equator. In other words, the characteristics of the instrument and orbiter combine to allow local, semidiurnal sampling of the atmosphere at synoptic or greater scales. This can be helpful at resolving diurnal and perhaps longitudinal variability when retrievals are typically successful on the nightside at different longitudes than they are successful on the dayside. Second, long-term monitoring allows fortuiitous observation of useful examples of interannual variability in the behavior of the atmosphere. Here, we will present a study of diurnal variability in the vertical dust distribution and other aspects of the atmospheric structure of Mars that makes use of the observational advantages of MRO-MCS as well as the fortuitous occurrence of a Mars Year without significant regional or global dust storm activity: the year before the landing of the Mars Science Laboratory

  10. Diurnal changes in the synthesis of the neurosteroid 7alpha-hydroxypregnenolone stimulating locomotor activity in newts.

    PubMed

    Koyama, Teppei; Haraguchi, Shogo; Vaudry, Hubert; Tsutsui, Kazuyoshi

    2009-04-01

    We recently identified 7alpha-hydroxypregnenolone as a novel amphibian neurosteroid stimulating locomotor activity in newts. Because male newts show marked diurnal changes in locomotor activity, we hypothesized that 7alpha-hydroxypregnenolone may be a key factor for the induction of diurnal changes in locomotor activity in male newts. In this study, we found diurnal changes in 7alpha-hydroxypregnenolone synthesis in the brain of male newts, which paralleled locomotor activity. Interestingly, the production of 7alpha-hydroxypregnenolone in the male newt brain increased during the dark phase when locomotor activity of males was high.

  11. The cosmic ray differential diurnal variation dependences on the zenith angle and the geomagnetic disturbance

    NASA Technical Reports Server (NTRS)

    Kavlakov, S.; Georgiev, L.

    1985-01-01

    Simultaneous and continuous muon measurements in two opposite azimuthal directions under equal zenith angles demonstrated the importance of this method for cosmic ray diurnal variation investigations. Lately these measurements were extended by means of improved telescopes. The obtained cosmic ray diurnal variations were presented as intensity differential curves. Theoretical investigations connected the properties of these curves with some interplanetary spece parameters. The harmonics of these curves were interpreted physically. Some order difference curves were introduced. In earlier works some dependences between the parameters characterizing the first and the second harmonics of the differential intensity curves and the geomagnetic activity were found. Then all measurements were carried out under only one zenith angle. The results of investigations of similar dependences using data of simultaneous measurements under three different zenith angles are presented.

  12. Solar tri-diurnal variation of cosmic rays in a wide range of rigidity

    NASA Technical Reports Server (NTRS)

    Mori, S.; Ueno, H.; Fujii, Z.; Morishita, I.; Nagashima, K.

    1985-01-01

    Solar tri-diurnal variations of cosmic rays have been analyzed in a wide range of rigidity, using data from neutron monitors, and the surface and underground muon telescopes for the period 1978-1983. The rigidity spectrum of the anisotropy in space is assumed to be of power-exponential type as (P/gamma P sub o) to the gamma exp (gamma-P/P sub o). By means of the best-fit method between the observed and the expected variations, it is obtained that the spectrum has a peak at P (=gamma P sub o) approx = 90 GV, where gamma=approx 3.0 and P sub o approx. 30 GV. The phase in space of the tri-diurnal variation is also obtained as 7.0 hr (15 hr and 23 hr LT), which is quite different from that of approx. 1 hr. arising from the axisymmetric distribution of cosmic rays with respect to the IMF.

  13. Diurnal variation of marine stratocumulus over San Nicolas Island during July 1987

    NASA Technical Reports Server (NTRS)

    Blaskovic, Miriam; Davies, Roger; Snider, J. B.

    1991-01-01

    A study is presented of surface measurements made at San Nicolas Island during the intensive field observation marine stratocumulus phase of the First International Satellite Cloud Climatology Program Regional Experiment, July 1987, to retrieve the average diurnal variation of marine stratocumulus and associated surface variables. The diurnal behavior of the cloud base appears to be consistent with model-predicted uncoupling of the cloud layer and the subcloud layer as the turbulent flux of moisture is limited by solar heating close to the cloud base. Also, variation in surface air temperature is consistent with the limitation of the turbulent flux of heat between the two layers, screening the surface from the effect of longwave cooling from the cloud top.

  14. Ten-Year Climatology of Summertime Diurnal Rainfall Rate Over the Conterminous U.S.

    NASA Technical Reports Server (NTRS)

    Matsui, Toshihisa; Mocko, David; Lee, Myong-In; Tao, Wei-Kuo; Suarez, Max J.; Pielke, Roger A., Sr.

    2010-01-01

    Diurnal cycles of summertime rainfall rates are examined over the conterminous United States, using radar-gauge assimilated hourly rainfall data. As in earlier studies, rainfall diurnal composites show a well-defined region of rainfall propagation over the Great Plains and an afternoon maximum area over the south and eastern portion of the United States. Zonal phase speeds of rainfall in three different small domains are estimated, and rainfall propagation speeds are compared with background zonal wind speeds. Unique rainfall propagation speeds in three different regions can be explained by the evolution of latent-heat theory linked to the convective available potential energy, than by gust-front induced or gravity wave propagation mechanisms.

  15. Estimates of riparian evapotranspiration using diurnal monitoring of groundwater regime in desert environments

    NASA Astrophysics Data System (ADS)

    Wang, P.; Pozdniakov, S. P.; Grinevsky, S.; Yu, J.

    2013-12-01

    Shallow groundwater is mainly discharged by phreatophytes in many riparian ecosystems of arid and semiarid environment, while estimation of groundwater evapotranspiration in these regions still remains a challenge for regional water resources assessment. In this study, a simple relationship between the average standard deviation of diurnal groundwater level fluctuations and the daily evapotranspiration over relatively short periods (days or weeks) was developed for estimating groundwater consumption by phreatophytes in arid/semi-arid areas. Our approach allows estimating groundwater evapotranspiration using stable statistical characteristics of diurnal groundwater fluctuation, and it is useful for analyzing large amounts of data obtained from digital groundwater level monitoring sensors. The developed methodology was applied to two phreatophyte-dominated riparian areas (Populus euphratica and Tamarix ramosissima) in a typical Gobi desert region of northwest China to demonstrate the usefulness of the technique.

  16. Climatology of Martian water ice clouds from Mars Express/OMEGA: derivation of the diurnal cycle

    NASA Astrophysics Data System (ADS)

    Szantai, A.; Audouard, J.; Madeleine, J.-B.; Forget, F.; Pottier, A.; Gondet, B.; Langevin, Y.; Bibring, J.-P.

    2015-10-01

    Images derived from the slope of the water ice absorption band between 3.4 and 3.525 μm from the OMEGA spectrometer onboard Mars Express have been used to detect clouds. From a series of OMEGA images covering 4 Martian years (between 2004 and 2011), the pixels are used to construct a cloud coverage database over a regular 4D grid in longitude,latitude, solar longitude and Martian local time. It can be used to observe the evolution of clouds over specific regions, and their diurnal and annual cycle. As an example, the diurnal cloud life cycle in the tropics (-25°S to 25°N) during the Northern summer shows the presence of thick clouds in the early morning (possibly haze), which dissipate before noon (local time). In the afternoon, the cloud cover grows again, possibly due to convection generated by the increased solar heating.

  17. Ozone Diurnal Variation in the PBL at the Boulder Atmospheric Observatory During Summer 2014

    NASA Astrophysics Data System (ADS)

    Newchurch, M.; Alvarez, R. J. _II, II; Brewer, A.; Brown, S. S.; Carrion, W.; Delgado, R.; De Young, R.; Huang, G.; Johnson, B.; Kuang, S.; Langford, A. O.; Lundquist, J. K.; McGee, T. J.; Pliutau, D.; Senff, C. J.; Sullivan, J. T.; Sumnicht, G. K.; Twigg, L.; Wang, L.

    2014-12-01

    We investigate the diurnal variation of PBL ozone at the Boulder Atmospheric Observatory (BAO) in July 2014 using multiple observations, including three ozone DIALs, several wind Doppler lidars, free-launched and tethered ozonesondes, and in-situ measurements on the BAO tower. Three mobile lidars from the Tropospheric Ozone Lidar NETwork (TOLNET) provide high spatial and temporal ozone profiles from near surface to the top of the troposphere. The combination of multiple observations will provide detailed structure of the diurnal variation of ozone. This ozone information will help the satellite and modeling communities to study the character of lower tropospheric ozone for the improvements of satellite retrieval and air-quality models. In addition, a Large-Eddy Simulation model will calculate ozone in the mixed layer to explain the processes responsible for the observations.

  18. Approximate Analytical Solution to Diurnal Atmospheric Boundary-Layer Growth Under Well-Watered Conditions

    NASA Astrophysics Data System (ADS)

    Rigby, J. R.; Yin, Jun; Albertson, John D.; Porporato, Amilcare

    2015-07-01

    Simplified numerical models of the atmospheric boundary layer (ABL) are useful both for understanding the underlying dynamics and potentially providing parsimonious modelling approaches for inclusion in larger models. Herein the governing equations of a simplified slab model of the uniformly mixed, purely convective, diurnal ABL are shown to allow immediate solutions for the potential temperature and specific humidity as functions of the ABL height and net radiation when expressed in integral form. By employing a linearized saturation vapour relation, the height of the mixed layer is shown to obey a non-linear ordinary differential equation with quadratic dependence on ABL height. A perturbation solution provides general analytical approximations, of which the leading term is shown to represent the contribution under equilibrium evaporation. These solutions allow the diurnal evolution of the height, potential temperature, and specific humidity (i.e., also vapour pressure deficit) of the mixed layer to be expressed analytically for arbitrary radiative forcing functions.

  19. Variability of radiatively forced diurnal cycle of intense convection in the tropical west pacific

    SciTech Connect

    Gray, W.M.; Sheaffer, J.D.; Thorson, W.B.

    1996-04-01

    Strong differences occur in daytime versus nighttime (DVN) net radiative cooling in clear versus cloudy areas of the tropical atmosphere. Daytime average cooling is approximately -0.7{degrees}C/day, whereas nighttime net tropospheric cooling rates are about -1.5{degrees}C/day, an approximately two-to-one difference. The comparatively strong nocturnal cooling in clear areas gives rise to a diurnally varying vertical circulation and horizontal convergence cycle. Various manifestations of this cyclic process include the observed early morning heavy rainfall maxima over the tropical oceans. The radiatively driven DVN circulation appears to strongly modulate the resulting diurnal cycle of intense convection which creates the highest, coldest cloudiness over maritime tropical areas and is likely a fundamental mechanism governing both small and large scale dynamics over much of the tropical environment.

  20. Elevated repetitive behaviors are associated with lower diurnal salivary cortisol levels in autism spectrum disorder.

    PubMed

    Gabriels, Robin L; Agnew, John A; Pan, Zhaoxing; Holt, Katherine D; Reynolds, Ann; Laudenslager, Mark L

    2013-05-01

    Previously, we reported a subgroup of children with autism spectrum disorders (ASD) had consistently high rates of repetitive behaviors (RBs) with abnormal sensory sensitivity. Given evidence of lower cortisol levels in response to stress and associated sensory sensitivity in the ASD population, this pilot study evaluates whether the presence of RBs reflects an underlying pathophysiology related to cortisol regulation. Diurnal salivary cortisol from 21 children with ASD and high versus low occurrence RBs were collected at four time points over three consecutive days. Although a typical decline in salivary cortisol was observed, participants in the high RB group showed 36% lower diurnal salivary cortisol than the low RB group. Age, IQ, RB type, and sleep quality were unrelated to observed differences. These findings suggest that RBs may serve to mitigate distress or that the glucocorticoid system has been down regulated in association with prolonged distress in this sample population.

  1. Diurnal locomotor activity and oxidative metabolism of the suprachiasmatic nucleus in two models of hepatic insufficiency.

    PubMed

    Lopez, Laudino; Cimadevilla, Jose M; Aller, Maria A; Arias, Jaime; Nava, M Paz; Arias, Jorge L

    2003-08-15

    Subjects with hepatic cirrhosis develop alterations of several rhythmic behavioural and biochemical patterns. Since most cirrhotic patients combine portal hypertension and hepatic impairment, our work aims to assess the extent to which rhythmical changes can be due to hepatic insufficiency or portal hypertension. This was done using two experimental models in rats, portacaval shunt model (PC) and portal hypertension by a triple stenosing ligature of the portal vein (PH). We assess diurnal locomotor activity and determine the oxidative metabolism of the suprachiasmatic nucleus (SCN) by histochemical determination of cytochrome oxidase (COX). The results show that animals with PC have altered diurnal locomotor rhythm compared to control and PH rats (p<0.001). They also present lower COX activity in the SCN (p<0.05). We conclude that rhythmic alterations are due to hepatic insufficiency and not to portal hypertension.

  2. Measurement of atmospheric NO3 2. Diurnal variation of stratospheric NO3 at midlatitude

    NASA Astrophysics Data System (ADS)

    Aliwell, S. R.; Jones, R. L.

    NO3 total column abundances covering the diurnal cycle were measured at midlatitude (52.4°N) during May 1995 by visible absorption spectroscopy using the Moon as a light source. The variation of measured slant column amounts with lunar zenith angle indicated that the NO3 was chiefly located within the stratosphere. Model calculations of the diurnal variation of NO3 at the measurement site give systematically lower column abundances than the measurements. This discrepancy may be explained by uncertainties in rate and equilibrium constant data used in the model calculations. A value for the equilibrium constant for N2O5 thermal decomposition of 2.7 ×1 0-27 exp(10500/T) cm³ molec.-1 and exp[-2425/T] for the activation energy of the reaction of O3 with NO2 to produce NO3 are suggested from the fit of modelled to experimental data.

  3. Diurnal changes in the partial pressure of carbon dioxide in coral reef waters

    SciTech Connect

    Kayanne, Hajime; Suzuki, Atsushi; Saito, Hiroshi

    1995-07-14

    Coral reefs are considered to be a source of atmospheric carbon dioxide because of their high calcium carbonate production and low net primary production. This was tested by direct measurement of diurnal changes in the partial pressure of carbon dioxide (P{sub CO2}) in reef waters during two 3-day periods, one in March 1993 and one in March 1994, on Shiraho reef of the Ryukyu Islands, Japan. Although the P{sub CO2} values in reef waters exhibited large diurnal changes ranging from 160 to 520 microatmospheres, they indicate that the reef flat area is a net sink for atmospheric carbon dioxide. This suggests that the net organic production rate of the reef community exceeded its calcium carbonate production rate during the observation periods. 16 refs., 2 figs., 1 tab.

  4. Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant.

    PubMed

    Joschinski, Jens; Beer, Katharina; Helfrich-Förster, Charlotte; Krauss, Jochen

    2016-01-01

    Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum(Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light-dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant's rhythmicity.

  5. Diurnal/Inertial Oscillations on the West Florida Shelf in the Eastern Gulf of Mexico.

    NASA Astrophysics Data System (ADS)

    Maksimova, E. V.; Weisberg, R. H.

    2015-12-01

    Oscillations of diurnal/inertial frequency on the West Florida Shelf in the Eastern Gulf of Mexico are thought to be seasonally important for mixing the shelf waters because of their tendency to have large vertical shear and to be quite energetic. Such oscillations are also thought to seasonally affect the ecology of the region through daily vertical thermocline migration. The presentation will focus on some novel findings about the diurnal/inertial coastal current fluctuations based on unique observational and modeled data sets on the West Florida Shelf. The properties of the oscillations, including spatial and temporal characteristics, and mechanisms of generation and propagation will be discussed. This presentation is based upon work supported by the National Science Foundation Ocean Sciences Postdoctoral Research Fellowship under Grant OCE-1421180 (E. V. Maksimova).

  6. The diurnal interaction between convection and peninsular-scale forcing over South Florida

    NASA Technical Reports Server (NTRS)

    Cooper, H. J.; Simpson, J.; Garstang, M.

    1982-01-01

    One of the outstanding problems in modern meterology is that of describing in detail the manner in which larger scales of motion interact with, influence and are influenced by successively smaller scales of motion. The present investigation is concerned with a study of the diurnal evolution of convection, the interaction between the peninsular-scale convergence and convection, and the role of the feedback produced by the cloud-scale downdrafts in the maintenance of the convection. Attention is given to the analysis, the diurnal cycle of the network area-averaged divergence, convective-scale divergence, convective mass transports, and the peninsular scale divergence. The links established in the investigation between the large scale (peninsular), the mesoscale (network), and the convective scale (cloud) are found to be of fundamental importance to the understanding of the initiation, maintenance, and decay of deep precipitating convection and to its theoretical parameterization.

  7. Diurnal Cycle of Convection in the East Pacific ITCZ during EPIC-2001

    NASA Technical Reports Server (NTRS)

    Boccippio, Dennis J.; Petersen, Walter A.; Cifelli, Robert; Rutledge, Steven A.; Arnold, James O. (Technical Monitor)

    2002-01-01

    During the last three weeks of September 2001, the EPIC-2001 intensive field campaign focused on studies of deep convection in the ITCZ over the Mexican warm pool region (10N, 95W) of the East Pacific. This study focuses on the pronounced observed diurnal cycle of environmental and convective parameters within the experiment domain. Data from three primary sources are examined: the R/V Ronald H. Brown C-band weather radar, 4-hourly soundings from the Brown and the Global Atmospherics, Inc. National Lightning Detection Network (long range product). Satellite data from TRMM, GOES and OV-1 are also used. The domain boundary layer shows a robust daily evolution of moist enthalpy (as reflect by equivalent potential temperature, theta-e, or wet bulb potential temperature, theta-w), with contributions from changes in both dry and moist entropy. Peak theta-w is found after local nightfall; the average diurnal range of theta-w is approximately 1 deg C. A composite diurnal cycle of convective properties was derived from the C-band volume scans, sampled continuously through the experiment at 10 minute updates. Products derived from the volumetric data include a surface PPI, 15 and 30 dBZ echo top height, vertically integrated liquid, and 6 km (mixed phase region) reflectivity CAPPIs. For almost all products, the parameter means showed virtually no diurnal cycle. However, for the upper-level products, the parameter spectra showed a clear peak in the occurrence of deep/vigorous convection (the "tail end of the distribution") between 7-9 UTC (1-3 AM local), while overall frequency of occurrence peaked later, from 12-15 UTC (6-9 AM local). This represents a daily "outbreak" of isolated deep cells a couple of hours after sunset and subsequent growth, organization and decay through the nighttime hours. The coherence of the diurnal cycle of the convective spectrum is impressive given the wide variety of convective organization observed during the experiment, and given the modulation

  8. Quasi-biennial oscillation signatures in the diurnal tidal winds over Cachoeira Paulista, Brazil

    NASA Astrophysics Data System (ADS)

    de Araújo, Luciana Rodrigues; Lima, Lourivaldo Mota; Jacobi, Christoph; Batista, Paulo Prado

    2017-03-01

    Mesosphere/lower thermosphere winds obtained by meteor radar over Cachoeira Paulista (22.7° S, 45.0° W), Brazil, have been used to investigate the interannual variability of the diurnal tidal (DT) wind amplitude. The monthly DT displays year to year variations and their amplitudes are strongest during the westerly phase of the quasi-biennial oscillation (QBO) at the 30 hPa level. This can be observed in all seasons in the meridional component, whilst in the zonal component the signal is clearer during austral autumn, when the diurnal tide is strongest in this latitude. The spectrum obtained from the deseasonalized amplitudes shows a peak near 26 months in the meridional component, which can be associated to the stratospheric QBO. The QBO modulation of the DT amplitude shows a quasi-decadal variation, and it is stronger during the maximum of the solar cycle.

  9. Results of diurnal anisotropy in CR intensity on different geomagnetic conditions.

    NASA Astrophysics Data System (ADS)

    Dubey, S. K.; Kumar, S.; Agrawal, R.

    2001-08-01

    Cosmic Ray intensity data for a period of eleven years (1985-95; which covers descending phase of the 21st solar cycle and ascending phase of the 22nd solar cycle alongwith the maximum and minimum solar activity periods), have been analysed using four different criteria for selection of days for such analysis. Study of diurnal anisotropy on different criteria shows that the phase of diurnal anisotropy during 1985-91, remains constant within the statistical error limits and in the later period it shifts to early hours in 1992-93 and then it shifts further to earlier hours in 1994 and 95. It is also found that the characteristics of daily variation in cosmic ray intensity are quite comparable for all the four different groups of days, during the period of investigation. 1Introduction Association between the Cosmic Ray (CR) intensity and solar transients are well established and effects of changing interplanetary conditions in the interplanetary space are reflected in spatial distribution of CR intensity which also affect geomagnetic activity index Kp or Ap. The anisotropic modulation in CR intensity on long/short term basis has been studied for diurnal anisotropy and for higher harmonics in CR intensity, satisfying different criteria. Kumar et al (1981; 87; 93; 98) studied the diurnal anisotropy on geomagnetically quietestdays(60QD);Whereas,Rao(1972), Agrawal (1983); Bieber and Evanson (1997); Ahluwalia (1999) have opted All Days (AD) for such analysis. Agrawal (1981) considered to perform study over continuous periods, where the monthly mean values of diurnal amplitude and/or phase are significantly different as compared to the annual average values. This situation led to a search for the most suitable criteria for selection of days for analysis of CR intensity data. In the present paper, an attempt has been made to study the CR diurnal variation on the basis of different criteria. 2 Data Analysis Days with lowest values of Ap and Kp are identified as

  10. Long-term effectiveness of the response restriction method for establishing diurnal bladder control.

    PubMed

    van Oorsouw, Wietske M W J; Duker, P C; Melein, L; Averink, M

    2009-01-01

    The long-term effectiveness of the response restriction method for establishing diurnal bladder control was assessed with 48 participants with intellectual disabilities. Intervals of assessment ranged from 28 to 66 months across the individuals following initial baseline. Difference scores in terms of the mean number of toileting accidents per hour were related to participants' stereotypic behaviour and their housing conditions, as these were hypothesized to differentially influence the maintenance of diurnal bladder control. It was found that (a) across all participants there was a statistically significant decrease of the mean number of toileting accidents during follow-up as compared to initial baseline (b) stereotypic behaviour failed to be related to maintenance of bladder control, and (c) housing condition was significantly related to the above dependent variable, in that those living in a residential facility were more likely to wear a diaper again as compared to those living with their family. Implications for the clinical practice are discussed.

  11. The complexity of diagnosing postural orthostatic tachycardia syndrome: influence of the diurnal variability.

    PubMed

    Moon, Jangsup; Lee, Han Sang; Byun, Jung-Ick; Sunwoo, Jun-Sang; Shin, Jung-Won; Lim, Jung-Ah; Kim, Tae-Joon; Shin, Yong-Won; Lee, Keon-Joo; Jeon, Daejong; Jung, Keun-Hwa; Lee, Soon-Tae; Jung, Ki-Young; Chu, Kon; Lee, Sang Kun

    2016-03-01

    We investigated how the diagnosis of postural orthostatic tachycardia syndrome (POTS) would be changed due to diurnal variability in orthostatic tachycardia. The orthostatic vital sign test was administered to each patient twice, in the afternoon of the day of admission and the next morning (n = 113). Forty-six patients were diagnosed with POTS, and the remaining 67 patients were assigned to non-POTS group. Heart rate increments after standing were larger in the morning than in the afternoon in every group (all P < .001). Among the POTS patients, 82.6% fulfilled the diagnostic criteria for POTS in the morning and 52.2% in the afternoon. Most POTS group (65.2%) displayed normal result on single orthostatic vital sign test. Orthostatic intolerance symptoms were provoked in only 45.7% of the POTS patients, more frequently in the morning. In conclusion, diurnal variability in hemodynamic parameters and provoked symptoms significantly challenged the diagnosis of POTS.

  12. Dependence of upper atmosphere photochemistry on the shape of the diurnal cycle of the photolysis rates

    NASA Astrophysics Data System (ADS)

    Montecinos, S.; Barrientos, P.

    2006-03-01

    A photochemical model of the atmosphere constitutes a non-linear, non-autonomous dynamical system, enforced by the Earth's rotation. Some studies have shown that the region of the mesopause tends towards non-linear responses such as period-doubling cascades and chaos. In these studies, simple go approximations for the diurnal variations of the photolysis rates are assumed. The goal of this article is to investigate what happens if the more realistic, calculated photolysis rates are introduced. It is found that, if the usual approximations-sinusoidal and step functions-are assumed, the responses of the system are similar: it converges to a 2-day periodic solution. If the more realistic, calculated diurnal cycle is introduced, a new 4-day subharmonic appear.

  13. Mechanisms of diurnal precipitation over the US Great Plains: a cloud resolving model perspective

    NASA Astrophysics Data System (ADS)

    Lee, Myong-In; Choi, Ildae; Tao, Wei-Kuo; Schubert, Siegfried D.; Kang, In-Sik

    2010-02-01

    The mechanisms of summertime diurnal precipitation in the US Great Plains were examined with the two-dimensional (2D) Goddard Cumulus Ensemble (GCE) cloud-resolving model (CRM). The model was constrained by the observed large-scale background state and surface flux derived from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program’s Intensive Observing Period (IOP) data at the Southern Great Plains (SGP). The model, when continuously-forced by realistic surface flux and large-scale advection, simulates reasonably well the temporal evolution of the observed rainfall episodes, particularly for the strongly forced precipitation events. However, the model exhibits a deficiency for the weakly forced events driven by diurnal convection. Additional tests were run with the GCE model in order to discriminate between the mechanisms that determine daytime and nighttime convection. In these tests, the model was constrained with the same repeating diurnal variation in the large-scale advection and/or surface flux. The results indicate that it is primarily the surface heat and moisture flux that is responsible for the development of deep convection in the afternoon, whereas the large-scale upward motion and associated moisture advection play an important role in preconditioning nocturnal convection. In the nighttime, high clouds are continuously built up through their interaction and feedback with long-wave radiation, eventually initiating deep convection from the boundary layer. Without these upper-level destabilization processes, the model tends to produce only daytime convection in response to boundary layer heating. This study suggests that the correct simulation of the diurnal variation in precipitation requires that the free-atmospheric destabilization mechanisms resolved in the CRM simulation must be adequately parameterized in current general circulation models (GCMs) many of which are overly sensitive to the parameterized boundary layer

  14. Mechanisms of Diurnal Precipitation over the United States Great Plains: A Cloud-Resolving Model Simulation

    NASA Technical Reports Server (NTRS)

    Lee, M.-I.; Choi, I.; Tao, W.-K.; Schubert, S. D.; Kang, I.-K.

    2010-01-01

    The mechanisms of summertime diurnal precipitation in the US Great Plains were examined with the two-dimensional (2D) Goddard Cumulus Ensemble (GCE) cloud-resolving model (CRM). The model was constrained by the observed large-scale background state and surface flux derived from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program s Intensive Observing Period (IOP) data at the Southern Great Plains (SGP). The model, when continuously-forced by realistic surface flux and large-scale advection, simulates reasonably well the temporal evolution of the observed rainfall episodes, particularly for the strongly forced precipitation events. However, the model exhibits a deficiency for the weakly forced events driven by diurnal convection. Additional tests were run with the GCE model in order to discriminate between the mechanisms that determine daytime and nighttime convection. In these tests, the model was constrained with the same repeating diurnal variation in the large-scale advection and/or surface flux. The results indicate that it is primarily the surface heat and moisture flux that is responsible for the development of deep convection in the afternoon, whereas the large-scale upward motion and associated moisture advection play an important role in preconditioning nocturnal convection. In the nighttime, high clouds are continuously built up through their interaction and feedback with long-wave radiation, eventually initiating deep convection from the boundary layer. Without these upper-level destabilization processes, the model tends to produce only daytime convection in response to boundary layer heating. This study suggests that the correct simulation of the diurnal variation in precipitation requires that the free-atmospheric destabilization mechanisms resolved in the CRM simulation must be adequately parameterized in current general circulation models (GCMs) many of which are overly sensitive to the parameterized boundary layer heating.

  15. Bounds on diurnal modulations from the COSME-II dark matter experiment

    NASA Astrophysics Data System (ADS)

    Collar, J. I.; Avignone, F. T.; Brodzinski, R. L.; Garcia, E.; Miley, H. S.; Morales, A.; Morales, J.; Nuñez-Lagos, R.; Reeves, J. H.; Saenz, C.; Villar, J. A.

    1992-07-01

    A search was conducted for diurnal modulation in the background of the 0.234 kg germanium detector, COSME-II, due to the hypothetized scattering of cold dark matter (CDM) particles in the Earth. Bounds on CDM are presented, and a theory of CDM scattering in the Earth is discussed. Operated for the U.S. Department of Energy by Battelle Memorial Institute under Contract DE-AC06-76RLO 1830.

  16. Diurnal and seasonal variations in leaf hydraulic conductance in evergreen and deciduous trees.

    PubMed

    Lo Gullo, Maria A; Nardini, Andrea; Trifilò, Patrizia; Salleo, Sebastiano

    2005-04-01

    We studied changes in the hydraulic conductance of leaves (K(leaf)) between dawn and dusk during the growth period (July) and at midday at the beginning of autumn in four tree species. The main objectives of the study were to check the extent of diurnal and seasonal changes in K(leaf) and the relationships between K(leaf), irradiance and leaf gas exchange. Two evergreen (Aleurites moluccana and Persea americana) and two deciduous trees (Platanus orientalis and Quercus rubra) were studied. Leaf hydraulic conductance was measured every 2 h between 0700 and 1900 h in July and compared with values measured between 0900 and 1300 h in October. Other variables measured were photosynthetically active radiation (PAR), leaf conductance to water vapor (gL) and water potential (psiL). In July, K(leaf) varied by up to 75% in Pe. americana on a diurnal basis and by at least 44% in Q. rubra. The diurnal time course of K(leaf) showed a distinct increase between dawn and late morning (1100 h) and a subsequent decrease in the evening in A. moluccana and Pl. orientalis, whereas in the other two species, K(leaf) was highest just after dawn and lowest in the evening. In October, K(leaf) of all the species studied was lower than in July, with differences of 20 to 28% for A. moluccana and Pl. orientalis and of 66 to over 70% in Pe. americana and Q. rubra, respectively. Significant correlations were found between PAR and K(leaf) (in all species) as well as between gL and K(leaf) (in three out of four species). Leaf habit (evergreen or deciduous) did not influence absolute values of K(leaf) or its diurnal variation.

  17. Diurnal and seasonal variation of coastal carbonate system parameters in South Florida and the Caribbean

    NASA Astrophysics Data System (ADS)

    Yates, K.; Smiley, N. A.

    2010-12-01

    Assessing the impact of climate change and ocean acidification on coastal and marine ecosystems requires accurate characterization of its chemical and physical effects on the carbonate system in seawater. Very few data exist that characterize natural variations in coastal carbonate chemistry, limiting the development and validation of coastal climate change and ocean acidification models. We measured carbonate system parameters over diurnal cycles in shallow, coastal ecosystems of Florida Bay, Tampa Bay, Biscayne National Park, Puerto Rico, the U.S. Virgin Islands, Tobago, and the Bahamas. Salinity, temperature, and dissolved oxygen were measured continuously, and seawater samples were collected every 4 hours throughout multiple 24-hour time periods. Total alkalinity and pH were measured using spectrophotometric techniques, dissolved inorganic carbon was measured via carbon coulometry, and remaining carbonate system parameters were calculated using CO2SYS. Seasonal variability was either determined from existing data sets, or modeled using salinity and temperature data collected from CTDs deployed at study locations or long-term monitoring sites. Results indicate that all carbonate system parameters showed distinct variation over diurnal timescales primarily due to productivity, respiration, and precipitation and dissolution of calcium carbonate. The average range of diurnal variation was up to 102% of the seasonal range of variability in carbonate chemistry. Our data indicate that use of seasonal data sets without careful consideration of diurnal variability (or vice versa) may impart significant error in calculation of annual carbon budgets and modeling carbon cycling in coastal ecosystems. Implications for modeling long-term impacts of ocean acidification in coastal ecosystems will be discussed.

  18. Repetitive ritalin treatment modulates the diurnal activity pattern of young SD male rats.

    PubMed

    Algahim, Mohame Fodhl; Yang, Pamela Boi; Burau, Keith Dean; Swann, Allan Craig; Dafny, Nachum

    2010-09-01

    Attention Deficit Hyperactivity Disorder (ADHD) is a common behavioral disorder of children and is treated by psychostimulants. Psychostimulant exposure to children at the time of neuronal development can cause behavioral and physiological changes continuing during adulthood. Most of the studies on psychostimulants investigate the acute effects of the drug. The objective of this study was to investigate whether acute or chronic exposure to methylphenidate (MPD), the drug most often used to treat ADHD in children, will modulate the diurnal activity pattern of young rats. Maintaining the diurnal activity pattern is a physiological process that regulates the internal homeostasis. Dose response protocol was used to study the effect of acute and chronic MPD in four young post natal day 40 (P 40) rat groups, (each N=8), as follows: saline (control) group, and 0.6, 2.5, or 10.0 mg/kg i.p. MPD groups, respectively. The experiment was performed over 11 consecutive days of continuous locomotor activity recording using the open field assay. The data evaluation was divided into four phases as follows: acute, induction, washout and expression phases. There was a dose-dependent increase in the average locomotor activity in the first few hours post-injection. Analysis of the diurnal rhythmic pattern of locomotion in the three dose groups compared to control demonstrated that only the 10.0 mg/kg MPD elicited significant changes in diurnal pattern activity in the washout and the expression phase. In addition, this study indicated that chronic MPD treatment elicits dose dependent anticipation and/or withdrawal and behavioral sensitization.

  19. Influence of dynamical equatorial flattening and orientation of a triaxial core on prograde diurnal polar motion

    NASA Astrophysics Data System (ADS)

    Sun, Rong; Shen, WenBin

    2016-04-01

    The noise floor of empirical models of diurnal Earth Rotation could reach as low as 1μas as shown by several recent studies. In another aspect, the differences between these empirical models with the theoretical model predictions given by IERS Convention (2010) for certain diurnal frequencies are more than 10 μas (e.g. K1). The traxiality of the core is ignored in the theoretical model given by IERS Convention (2010) because it is highly uncertain. To explain the difference between the empirical model and theoretical model, we consider the possible influence of a triaxial core. We use the difference between empirical models and theoretical model predictions given by IERS Convention (2010) as input to invert the traxiality parameter of the core. In the inversion, we assume the ocean tide response obeys the admittance theory. So extra six admittance parameters are introduced to model the difference between smooth responses inferred from empirical models and that given by theoretical model predictions from IERS Convention (2010). The results show that adding core triaxiality into the theoretical model could narrow the difference between empirical model and theoretical model at diurnal frequencies. The residual of amplitude becomes smaller. For a set of tide components consisting of seven diurnal frequencies (Q1, O1, M1, P1, K1, J1, Oo1), the root mean square of the residual of this set have decreased from more than 10μas to 2˜3μas for most of the empirical models. As for the dynamical equatorial flattening of the core, estimates inverted based on different empirical models are consistent within standard deviation. The results also suggest that the principal axes of the triaxial core does not coincidence with the principal axes of the whole Earth. This study is supported by National 973 Project China (grant No. 2013CB733305), NSFC (grant Nos. 41174011, 41210006, 41504019).

  20. Behavioral, morphological and physiological correlates of diurnal and nocturnal vision in selected wading bird species.

    PubMed

    Rojas, L M; McNeil, R; Cabana, T; Lachapelle, P

    1999-01-01

    We examined in selected wading bird species if diurnal or nocturnal foraging and the use of visual or tactile feeding strategies could be correlated with retinal structure and function. The selected species were the Yellow-crowned Night Heron (Nycticorax violaceus), a crepuscular and nocturnal forager, the Great Blue Heron (Ardea herodias), a mainly crepuscular, but also diurnal and nocturnal feeder, the Roseate Spoonbill (Ajaia ajaja), a mainly crepuscular feeder which forages more at night than during the day, the Cattle (Bubulcus ibis) and Tricolored (Egretta tricolor) egrets and the American White Ibis (Eudocimus ruber) which forage only during daytime. Herons and egrets are visual foragers; ibises and spoonbills are tactile feeders. Electroretinograms were obtained from anesthetized birds in photopic and scotopic conditions to a wide range of light intensities, following which the retinae were processed for histological analysis. Based on rod densities and rods:cones ratios, nocturnal vision capability is greater in the Yellow-crowned Night Heron, followed by the Great Blue Heron and the spoonbill, then by the egrets and the ibis. Visual feeders that forage near dawn or dusk or at night have a higher rods:cones ratio, and consequently a greater night vision capability, than visual feeding species which forage only during daytime. Visual nocturnal feeders have a night vision capability greater than tactile diurnal as well as tactile nocturnal feeders. However, based on maximum scotopic b-wave amplitudes, all species studied have roughly comparable night vision capability. The factor that best discriminates between wading bird species appears to be the daytime visual capabilities. Indeed, the diurnal ibis and egrets have similar cone densities, cones:rods ratios, and photopic a-wave amplitudes, values which are greater than those measured in the two nocturnally active heron species.

  1. Modeling the diurnal variability of respiratory fluxes in the Canadian Terrestrial Ecosystem Model (CTEM)

    NASA Astrophysics Data System (ADS)

    Badawy, Bakr; Arora, Vivek K.; Melton, Joe R.; Nassar, Ray

    2016-06-01

    The Canadian Terrestrial Ecosystem Model (CTEM) coupled to the Canadian Land Surface Scheme (CLASS) is a dynamic vegetation model that incorporates photosynthesis and respiration submodules among many other physiological processes of the terrestrial biosphere. While the photosynthesis and leaf respiration submodules of CTEM operate at a time step of 30 min, other respiratory fluxes are estimated at a daily time step using the daily-averaged values of canopy and soil temperature, and soil moisture content. Here we modify CTEM to be able to simulate the diurnal variation of ecosystem respiratory fluxes caused by the diurnal variation in the driving climate data. Simulating respiration at a 30 min time step changed the equilibrium states of primary carbon pools and fluxes. This required changes to some of the model's parameters in order to realistically simulate the equilibrium values of carbon pools and fluxes. The resulting estimated daily and annual carbon fluxes from the modified and original CTEM are similar with small relative differences. The similar annual cycles of daily values of primary CO2 fluxes confirm that modeling the respiratory fluxes at a subdaily time step does not affect the annual cycles of these fluxes. We also demonstrate that the modified version of the model is able to simulate the diurnal cycle of net ecosystem exchange of CO2 fluxes that are broadly comparable to observation-based estimates at two flux tower sites and exhibit realistic seasonal patterns. Limitations remain in the modeled diurnal patterns of primary land-atmosphere CO2 fluxes which will form the basis of further model improvements.

  2. Practical limitations on the use of diurnal temperature signals to quantify groundwater upwelling

    NASA Astrophysics Data System (ADS)

    Briggs, Martin A.; Lautz, Laura K.; Buckley, Sean F.; Lane, John W.

    2014-11-01

    Groundwater upwelling to streams creates unique habitat by influencing stream water quality and temperature; upwelling zones also serve as vectors for contamination when groundwater is degraded. Temperature time series data acquired along vertical profiles in the streambed have been applied to simple analytical models to determine rates of vertical fluid flux. These models are based on the downward propagation characteristics (amplitude attenuation and phase-lag) of the surface diurnal signal. Despite the popularity of these models, there are few published characterizations of moderate-to-strong upwelling. We attribute this limitation to the thermodynamics of upwelling, under which the downward conductive signal transport from the streambed interface occurs opposite the upward advective fluid flux. Governing equations describing the advection-diffusion of heat within the streambed predict that under upwelling conditions, signal amplitude attenuation will increase, but, counterintuitively, phase-lag will decrease. Therefore the extinction (measurable) depth of the diurnal signal is very shallow, but phase lag is also short, yielding low signal to noise ratio and poor model sensitivity. Conversely, amplitude attenuation over similar sensor spacing is strong, yielding greater potential model sensitivity. Here we present streambed thermal time series over a range of moderate to strong upwelling sites in the Quashnet River, Cape Cod, Massachusetts. The predicted inverse relationship between phase-lag and rate of upwelling was observed in the field data over a range of conditions, but the observed phase-lags were consistently shorter than predicted. Analytical solutions for fluid flux based on signal amplitude attenuation return results consistent with numerical models and physical seepage meters, but the phase-lag analytical model results are generally unreasonable. Through numerical modeling we explore reasons why phase-lag may have been over-predicted by the

  3. Practical limitations on the use of diurnal temperature signals to quantify groundwater upwelling

    USGS Publications Warehouse

    Briggs, Martin; Lautz, Laura K.; Buckley, Sean F.; Lane, Jr., John W.

    2014-01-01

    Groundwater upwelling to streams creates unique habitat by influencing stream water quality and temperature; upwelling zones also serve as vectors for contamination when groundwater is degraded. Temperature time series data acquired along vertical profiles in the streambed have been applied to simple analytical models to determine rates of vertical fluid flux. These models are based on the downward propagation characteristics (amplitude attenuation and phase-lag) of the surface diurnal signal. Despite the popularity of these models, there are few published characterizations of moderate-to-strong upwelling. We attribute this limitation to the thermodynamics of upwelling, under which the downward conductive signal transport from the streambed interface occurs opposite the upward advective fluid flux. Governing equations describing the advection–diffusion of heat within the streambed predict that under upwelling conditions, signal amplitude attenuation will increase, but, counterintuitively, phase-lag will decrease. Therefore the extinction (measurable) depth of the diurnal signal is very shallow, but phase lag is also short, yielding low signal to noise ratio and poor model sensitivity. Conversely, amplitude attenuation over similar sensor spacing is strong, yielding greater potential model sensitivity. Here we present streambed thermal time series over a range of moderate to strong upwelling sites in the Quashnet River, Cape Cod, Massachusetts. The predicted inverse relationship between phase-lag and rate of upwelling was observed in the field data over a range of conditions, but the observed phase-lags were consistently shorter than predicted. Analytical solutions for fluid flux based on signal amplitude attenuation return results consistent with numerical models and physical seepage meters, but the phase-lag analytical model results are generally unreasonable. Through numerical modeling we explore reasons why phase-lag may have been over-predicted by the

  4. Sex hormones adjust "sex-specific" reactive and diurnal cortisol profiles.

    PubMed

    Juster, Robert-Paul; Raymond, Catherine; Desrochers, Alexandra Bisson; Bourdon, Olivier; Durand, Nadia; Wan, Nathalie; Pruessner, Jens C; Lupien, Sonia J

    2016-01-01

    Sex differences in stress hormone functions are presumed to depend on sex hormones. And yet, surprisingly few psychoneuroendocrine studies actually assess within-sex variations of testosterone, estradiol, and progesterone when investigating sex-specific activities of the hypothalamic-pituitary-adrenal axis. In this methodological study of 204 healthy adults (60 men), we assessed whether cortisol profiles would differ between the sexes when unadjusted or adjusted for basal sex hormones among both sexes. Reactive cortisol was sampled using 6 saliva samples measured every 10-min as part of the Trier Social Stress Test that generally activates cortisol among men more than women. Diurnal cortisol was sampled over two days at (1) awakening, (2) 30-min thereafter, (3) 1400 h, (4) 1600 h, and (5) bedtime. Sex hormones were collected at baseline before the psychosocial stressor and on two occasions during diurnal cortisol assessment. Repeated-measures analysis of covariance controlled for key covariates in analyses unadjusted or adjusted for sex hormones. Results revealed that men had higher reactive cortisol than women in unadjusted analysis, but this sex difference was attenuated when adjusting for sex hormones. While diurnal cortisol showed no sex differences in unadjusted models, adjusting for sex hormones revealed that women have higher morning cortisol. Correlations using area under the curve formulae revealed intriguing sex-specific associations with progesterone in men and testosterone in women that we propose have implications for social and affective neuroscience. In summary, our results reveal that adjusting for sex hormones alters "sex-specific" reactive and diurnal cortisol profiles.

  5. Diurnal cortisol rhythms in Tsimane' Amazonian foragers: new insights into ecological HPA axis research.

    PubMed

    Nyberg, Colleen H

    2012-02-01

    Although a growing body of research has documented important pathways by which the HPA axis mediates the interface between the psychosocial world and individual health, there is a paucity of data from nonwestern populations, particularly from those populations with distinct nutritional and infectious disease ecologies. The specific objectives of this study are: (1) to document variation in diurnal cortisol rhythms among the Tsimane', a remote population in the Bolivian Amazon, (2) to explore this variation by age and by gender, and (3) to compare diurnal rhythms from this study to other population based studies of cortisol conducted in industrialized nations. Salivary cortisol samples were collected twice daily, immediately upon waking and before bed, for three consecutive days from 303 participants (age 1.6-82 years, 1564 samples) in conjunction with the Tsimane' Amazonian Panel Study (TAPS). Cortisol rhythms showed strong age effects across the developmental span, with basal levels and slopes increasing into adulthood, although individuals older than 60 years demonstrated a precipitous flattening of the diurnal slope. Cortisol profiles were elevated in adult females compared to their age-matched male counterparts, and diurnal slopes, as well as mean cortisol concentrations among the Tsimane' were the lowest reported in any population based study of HPA axis function. Although the within-population variation in cortisol profiles was consistent with the established correlates of time of day, age, and sex, the between-population comparisons revealed dramatically lower levels of HPA activity among the Tsimane'. This study provides a benchmark against which to reference cortisol levels from industrialized populations, and expands the range of documented variation in HPA axis function in a nonwestern context.

  6. Chronic ethanol consumption disrupts diurnal rhythms of hepatic glycogen metabolism in mice

    PubMed Central

    Udoh, Uduak S.; Swain, Telisha M.; Filiano, Ashley N.; Gamble, Karen L.; Young, Martin E.

    2015-01-01

    Chronic ethanol consumption has been shown to significantly decrease hepatic glycogen content; however, the mechanisms responsible for this adverse metabolic effect are unknown. In this study, we examined the impact chronic ethanol consumption has on time-of-day-dependent oscillations (rhythms) in glycogen metabolism processes in the liver. For this, male C57BL/6J mice were fed either a control or ethanol-containing liquid diet for 5 wk, and livers were collected every 4 h for 24 h and analyzed for changes in various genes and proteins involved in hepatic glycogen metabolism. Glycogen displayed a robust diurnal rhythm in the livers of mice fed the control diet, with the peak occurring during the active (dark) period of the day. The diurnal glycogen rhythm was significantly altered in livers of ethanol-fed mice, with the glycogen peak shifted into the inactive (light) period and the overall content of glycogen decreased compared with controls. Chronic ethanol consumption further disrupted diurnal rhythms in gene expression (glycogen synthase 1 and 2, glycogenin, glucokinase, protein targeting to glycogen, and pyruvate kinase), total and phosphorylated glycogen synthase protein, and enzyme activities of glycogen synthase and glycogen phosphorylase, the rate-limiting enzymes of glycogen metabolism. In summary, these results show for the first time that chronic ethanol consumption disrupts diurnal rhythms in hepatic glycogen metabolism at the gene and protein level. Chronic ethanol-induced disruption in these daily rhythms likely contributes to glycogen depletion and disruption of hepatic energy homeostasis, a recognized risk factor in the etiology of alcoholic liver disease. PMID:25857999

  7. Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

    EPA Pesticide Factsheets

    There is no EPA generated dataset in this study.This dataset is associated with the following publication:Zhu, L., D. Henze, J. Bash , G. Jeong, K. Cady-Pereira, M. Shephard, M. Luo, F. Poulot, and S. Capps. Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 15: 12823-12843, (2015).

  8. Simulation of the Diurnal Cycle of Integrated Precipitable Water in the North American Monsoon Region

    NASA Astrophysics Data System (ADS)

    Ochoa, C. A.; Quintanar, A.; Adams, D. K.; Martinez-lopez, B.

    2015-12-01

    Organized deep convection over the North American monsoon region (NAM) is a salient climatic feature that has been the subject of several experimental campaigns and modeling efforts. Recently, however, in Mexico and the Caribbean, there has been mounting interest towards implementing low-cost, low-maintenance GPS-meteorological networks (TLALOCNet and COCOnet) that provide near real-time Integrated Precipitable Water data (IPW) into the assimilation cycle of regional models. A wealth of interesting new observational results concerning the link between the diurnal cycle of deep convection and the processes that could alter it at the surface and aloft has open up opportunities of model verification and improvements to the physics that are specific to subtropical deep convection. In this work, the diurnal cycle of IPW is studied using observational data collected during the North American Monsoon GPS Transect Experiment 2013 experiment and numerical simulations with the Weather Research and Forecasting model (WRF). WRF was run in climate mode to generate a simulation for the entire experiment using ECMWF ERA-Interim analysis data for initial and boundary conditions and spectral nudging. We classified the days during the experiment, according to type of mesoscale phenomena present each day and averaged days with same weather types in both data sets (observed and simulated). Preliminary results show that the simulated diurnal cycle of IPW is very sensitive to Land Use/Land Cover data and to initial and the boundary conditions. Preliminary results show that the simulated amplitude and phase of the diurnal cycle of IPW is well represented only when a more up-to-date LULC is used (MODIS v.s. 99 USGS LULC) and the Thompson mycrophysics scheme is used. In agreement with the previous results, modeled precipitation time series agree better with observed GPS-meterological station reports during the NAM 2013 experiment.

  9. Global transcriptomic analysis of Cyanothece 51142 reveals robust diurnal oscillation of central metabolic processes.

    PubMed

    Stöckel, Jana; Welsh, Eric A; Liberton, Michelle; Kunnvakkam, Rangesh; Aurora, Rajeev; Pakrasi, Himadri B

    2008-04-22

    Cyanobacteria are photosynthetic organisms and are the only prokaryotes known to have a circadian lifestyle. Unicellular diazotrophic cyanobacteria such as Cyanothece sp. ATCC 51142 produce oxygen and can also fix atmospheric nitrogen, a process exquisitely sensitive to oxygen. To accommodate such antagonistic processes, the intracellular environment of Cyanothece oscillates between aerobic and anaerobic conditions during a day-night cycle. This is accomplished by temporal separation of the two processes: photosynthesis during the day and nitrogen fixation at night. Although previous studies have examined periodic changes in transcript levels for a limited number of genes in Cyanothece and other unicellular diazotrophic cyanobacteria, a comprehensive study of transcriptional activity in a nitrogen-fixing cyanobacterium is necessary to understand the impact of the temporal separation of photosynthesis and nitrogen fixation on global gene regulation and cellular metabolism. We have examined the expression patterns of nearly 5,000 genes in Cyanothece 51142 during two consecutive diurnal periods. Our analysis showed that approximately 30% of these genes exhibited robust oscillating expression profiles. Interestingly, this set included genes for almost all central metabolic processes in Cyanothece 51142. A transcriptional network of all genes with significantly oscillating transcript levels revealed that the majority of genes encoding enzymes in numerous individual biochemical pathways, such as glycolysis, oxidative pentose phosphate pathway, and glycogen metabolism, were coregulated and maximally expressed at distinct phases during the diurnal cycle. These studies provide a comprehensive picture of how a physiologically relevant diurnal light-dark cycle influences the metabolism in a photosynthetic bacterium.

  10. Diurnal anisotropy of cosmic rays during intensive solar activity for the period 2001-2014

    NASA Astrophysics Data System (ADS)

    Tezari, A.; Mavromichalaki, H.

    2016-07-01

    The diurnal variation of cosmic ray intensity, based on the records of two neutron monitor stations at Athens (Greece) and Oulu (Finland) for the time period 2001 to 2014, is studied. This period covers the maximum and the descending phase of the solar cycle 23, the minimum of the solar cycles 23/24 and the ascending phase of the solar cycle 24.These two stations differ in their geographic latitude and magnetic threshold rigidity. The amplitude and phase of the diurnal anisotropy vectors have been calculated on annual and monthly basis. From our analysis it is resulted that there is a different behaviour in the characteristics of the diurnal anisotropy during the different phases of the solar cycle, depended on the solar magnetic field polarity, but also during extreme events of solar activity, such as Ground Level Enhancements and cosmic ray events, such as Forbush decreases and magnetospheric events. These results may be useful to Space Weather forecasting and especially to Biomagnetic studies.

  11. Effect of diurnal temperature difference on lipid accumulation and development in Calanus sinicus (Copepoda: Calanoida)

    NASA Astrophysics Data System (ADS)

    Zhou, Konglin; Sun, Song

    2016-08-01

    Calanus sinicus, the dominant copepod in the Yellow Sea, develops a large oil sac in late spring to prepare for over-summering in the Yellow Sea Cold Water Mass (YSCWM). The lipid accumulation mechanism for the initiation of over-summering is unknown. Here, we cultured C3 copepodites at four constant temperatures (10, 13, 16, and 19°C) and at three temperature regimes that mimicked the temperature variations experienced during diurnal vertical migration (10-13°C, 10-16°C, and 10-19°C) for 18 days to explore the effects of temperature differences on copepod development and lipid accumulation. C. sinicus stored more lipid at low than at high temperatures. A diurnal temperature difference (10-16°C and 10-19°C) promoted greater lipid accumulation (1.9-2.1 times) than a constant temperature of either 16°C or 19°C, by reducing the energy cost at colder temperatures and lengthening copepodite development. Thereafter, the lipid reserve supported gonad development after final molting. Only one male developed in these experiments. This highly female-skewed sex ratio may have been the result of the monotonous microalgae diet fed to the copepodites. This study provides the first evidence that diurnal temperature differences may promote lipid accumulation in C. sinicus, and provides a foundation for future investigations into the mechanisms involved in over-summering in the YSCWM.

  12. Diurnal Rhythms Result in Significant Changes in the Cellular Protein Complement in the Cyanobacterium Cyanothece 51142

    SciTech Connect

    Stockel, Jana; Jacobs, Jon M.; Elvitigala, Thanura R.; Liberton, Michelle L.; Welsh, Eric A.; Polpitiya, Ashoka D.; Gritsenko, Marina A.; Nicora, Carrie D.; Koppenaal, David W.; Smith, Richard D.; Pakrasi, Himadri B.

    2011-02-22

    Cyanothece sp. ATCC 51142 is a diazotrophic cyanobacterium notable for its ability to perform oxygenic photosynthesis and dinitrogen fixation in the same single cell. Previous transcriptional analysis revealed that the existence of these incompatible cellular processes largely depends on tightly synchronized expression programs involving ,30% of genes in the genome. To expand upon current knowledge, we have utilized sensitive proteomic approaches to examine the impact of diurnal rhythms on the protein complement in Cyanothece 51142. We found that 250 proteins accounting for,5% of the predicted ORFs from the Cyanothece 51142 genome and 20% of proteins detected under alternating light/dark conditions exhibited periodic oscillations in their abundances. Our results suggest that altered enzyme activities at different phases during the diurnal cycle can be attributed to changes in the abundance of related proteins and key compounds. The integration of global proteomics and transcriptomic data further revealed that post-transcriptional events are important for temporal regulation of processes such as photosynthesis in Cyanothece 51142. This analysis is the first comprehensive report on global quantitative proteomics in a unicellular diazotrophic cyanobacterium and uncovers novel findings about diurnal rhythms.

  13. Target Detection over the Diurnal Cycle Using a Multispectral Infrared Sensor

    PubMed Central

    Zhao, Huijie; Ji, Zheng; Li, Na; Gu, Jianrong; Li, Yansong

    2016-01-01

    When detecting a target over the diurnal cycle, a conventional infrared thermal sensor might lose the target due to the thermal crossover, which could happen at any time throughout the day when the infrared image contrast between target and background in a scene is indistinguishable due to the temperature variation. In this paper, the benefits of using a multispectral-based infrared sensor over the diurnal cycle have been shown. Firstly, a brief theoretical analysis on how the thermal crossover influences a conventional thermal sensor, within the conditions where the thermal crossover would happen and why the mid-infrared (3~5 μm) multispectral technology is effective, is presented. Furthermore, the effectiveness of this technology is also described and we describe how the prototype design and multispectral technology is employed to help solve the thermal crossover detection problem. Thirdly, several targets are set up outside and imaged in the field experiment over a 24-h period. The experimental results show that the multispectral infrared imaging system can enhance the contrast of the detected images and effectively solve the failure of the conventional infrared sensor during the diurnal cycle, which is of great significance for infrared surveillance applications. PMID:28036073

  14. Diurnal regulation of MTP and plasma triglyceride by CLOCK is mediated by SHP.

    PubMed

    Pan, Xiaoyue; Zhang, Yuxia; Wang, Li; Hussain, M Mahmood

    2010-08-04

    We examined the role of clock genes in the diurnal regulation of plasma triglyceride-rich apolipoprotein B-lipoproteins and their biosynthetic chaperone, microsomal triglyceride transfer protein (MTP). Clock(mt/mt) mice showed sustained hypertriglyceridemia and high MTP expression. CLOCK knockdown activated MTP promoter and reduced small heterodimer partner (SHP, NROB2). CLOCK upregulated SHP by binding to its E box. SHP suppressed MTP expression by binding to the HNF4alpha/LRH-1 at the MTP promoter. Cyclic expression of MTP after serum shock was abrogated by siCLOCK and siSHP. Plasma triglyceride and MTP showed reduced diurnal variations in Shp(-/-) mice. Whereas peaks and nadirs in SHP expression were inversely correlated with those of MTP, these changes were reduced in Clock(mt/mt) mice. Expression of Shp abrogated hypertriglyceridemia in Clock(mt/mt) mice. Together, these studies describe a role of Clock/Shp in the diurnal regulation of MTP and plasma triglyceride and indicate that disruptions in circadian regulation might cause hyperlipidemia.

  15. Diurnal Temperature Variations Affect Development of a Herbivorous Arthropod Pest and its Predators

    PubMed Central

    Vangansbeke, Dominiek; Audenaert, Joachim; Nguyen, Duc Tung; Verhoeven, Ruth; Gobin, Bruno; Tirry, Luc; De Clercq, Patrick

    2015-01-01

    The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen’s inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and +15°C) on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen’s inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes. PMID:25874697

  16. From dusk till dawn: nocturnal and diurnal pollination in the epiphyte Tillandsia heterophylla (Bromeliaceae).

    PubMed

    Aguilar-Rodríguez, P A; Krömer, T; García-Franco, J G; MacSwiney G, M C

    2016-01-01

    In order to compare the effectiveness of diurnal and nocturnal pollinators, we studied the reproductive biology and pollinators of Tillandsia heterophylla E. Morren, an epiphytic tank bromeliad endemic to southeastern Mexico. Since anthesis in T. heterophylla is predominantly nocturnal but lasts until the following day, we hypothesised that this bromeliad would receive visits from both diurnal and nocturnal visitors, but that nocturnal visitors would be the most effective pollinators, since they arrive first to the receptive flower, and that bats would be the most frequent nocturnal visitors, given the characteristics of the nectar. Flowering of T. heterophylla began in May and lasted until July. The species is fully self-compatible, with an anthesis that lasts for ca. 15-16 h. Mean volume of nectar produced per flower was 82.21 μl, with a mean sugar concentration of 6.33%. The highest volume and concentration of nectar were found at 20:00 h, with a subsequent decline in both to almost zero over the following 12-h period. T. heterophylla has a generalist pollination system, since at least four different morphospecies of visitors pollinate its flowers: bats, moths, hummingbirds and bees. Most of the pollinating visits corresponded to bats and took place in the early evening, when stigma receptivity had already begun; making bats the probable pollinator on most occasions. However, diurnal pollinators may be important as a 'fail-safe' system by which to guarantee the pollination of T. heterophylla.

  17. The Unique Impact of Late-Life Bereavement and Prolonged Grief on Diurnal Cortisol

    PubMed Central

    2014-01-01

    Objectives. This study expands on previous research by examining the effects of prolonged grief disorder (PGD) symptoms and bereavement on diurnal cortisol patterns above and beyond depressive symptomatology. Methods. Drawing on information from 56 depressed older adults, 3 groups were compared: (1) a depressed nonbereaved group, (2) a depressed bereaved without elevated PGD symptoms group, and (3) a depressed bereaved with elevated PGD symptoms group. Multilevel modeling was used to examine differences in diurnal cortisol profiles between these 3 groups, controlling for demographic factors and depressive symptoms. Results. Results revealed that those who were bereaved had more dysregulated cortisol patterns, but PGD symptomatology seemed to have little effect. Subsidiary analysis with just the bereaved participants suggests that those who were recently widowed may have had greater cortisol dysregulation compared with other bereaved individuals in the sample. Discussion. These findings suggest that the circumstance of being bereaved may be associated with more dysregulated cortisol, regardless of PGD symptomatology. This pattern of results might reflect greater disturbance in daily routines among bereaved individuals and acute stress in the case of those experiencing the recent loss of a spouse, which leads to disruption in circadian rhythms and the diurnal cycle of cortisol. PMID:23740094

  18. Spatial and diurnal below canopy evaporation in a desert vineyard: Measurements and modeling

    NASA Astrophysics Data System (ADS)

    Kool, D.; Ben-Gal, A.; Agam, N.; Šimůnek, J.; Heitman, J. L.; Sauer, T. J.; Lazarovitch, N.

    2014-08-01

    Evaporation from the soil surface (E) can be a significant source of water loss in arid areas. In sparsely vegetated systems, E is expected to be a function of soil, climate, irrigation regime, precipitation patterns, and plant canopy development and will therefore change dynamically at both daily and seasonal time scales. The objectives of this research were to quantify E in an isolated, drip-irrigated vineyard in an arid environment and to simulate below canopy E using the HYDRUS (2-D/3-D) model. Specific focus was on variations of E both temporally and spatially across the inter-row. Continuous above canopy measurements, made in a commercial vineyard, included evapotranspiration, solar radiation, air temperature and humidity, and wind speed and direction. Short-term intensive measurements below the canopy included actual and potential E and solar radiation along transects between adjacent vine-rows. Potential and actual E below the canopy were highly variable, both diurnally and with distance from the vine-row, as a result of shading and distinct wetted areas typical to drip irrigation. While the magnitude of actual E was mostly determined by soil water content, diurnal patterns depended strongly on position relative to the vine-row due to variable shading patterns. HYDRUS (2-D/3-D) successfully simulated the magnitude, diurnal patterns, and spatial distribution of E, including expected deviations as a result of variability in soil saturated hydraulic conductivity.

  19. Target Detection over the Diurnal Cycle Using a Multispectral Infrared Sensor.

    PubMed

    Zhao, Huijie; Ji, Zheng; Li, Na; Gu, Jianrong; Li, Yansong

    2016-12-29

    When detecting a target over the diurnal cycle, a conventional infrared thermal sensor might lose the target due to the thermal crossover, which could happen at any time throughout the day when the infrared image contrast between target and background in a scene is indistinguishable due to the temperature variation. In this paper, the benefits of using a multispectral-based infrared sensor over the diurnal cycle have been shown. Firstly, a brief theoretical analysis on how the thermal crossover influences a conventional thermal sensor, within the conditions where the thermal crossover would happen and why the mid-infrared (3~5 μm) multispectral technology is effective, is presented. Furthermore, the effectiveness of this technology is also described and we describe how the prototype design and multispectral technology is employed to help solve the thermal crossover detection problem. Thirdly, several targets are set up outside and imaged in the field experiment over a 24-h period. The experimental results show that the multispectral infrared imaging system can enhance the contrast of the detected images and effectively solve the failure of the conventional infrared sensor during the diurnal cycle, which is of great significance for infrared surveillance applications.

  20. Diurnal temperature variations affect development of a herbivorous arthropod pest and its predators.

    PubMed

    Vangansbeke, Dominiek; Audenaert, Joachim; Nguyen, Duc Tung; Verhoeven, Ruth; Gobin, Bruno; Tirry, Luc; De Clercq, Patrick

    2015-01-01

    The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen's inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and +15°C) on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen's inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes.

  1. Large Eddy Simulation of the Diurnal Cycle in Southeast Pacific Stratocumulus

    SciTech Connect

    Caldwell, P; Bretherton, C

    2008-03-03

    This paper describes a series of 6 day large eddy simulations of a deep, sometimes drizzling stratocumulus-topped boundary layer based on forcings from the East Pacific Investigation of Climate (EPIC) 2001 field campaign. The base simulation was found to reproduce the observed mean boundary layer properties quite well. The diurnal cycle of liquid water path was also well captured, although good agreement appears to result partially from compensating errors in the diurnal cycles of cloud base and cloud top due to overentrainment around midday. At other times of the day, entrainment is found to be proportional to the vertically-integrated buoyancy flux. Model stratification matches observations well; turbulence profiles suggest that the boundary layer is always at least somewhat decoupled. Model drizzle appears to be too sensitive to liquid water path and subcloud evaporation appears to be too weak. Removing the diurnal cycle of subsidence had little effect on simulated cloud albedo. Simulations with changed droplet concentration and drizzle susceptibility showed large liquid water path differences at night, but differences were quite small at midday. Droplet concentration also had a significant impact on entrainment, primarily through droplet sedimentation feedback rather than through drizzle processes.

  2. Diel Variation in Flower Scent Reveals Poor Consistency of Diurnal and Nocturnal Pollination Syndromes in Sileneae.

    PubMed

    Prieto-Benítez, Samuel; Dötterl, Stefan; Giménez-Benavides, Luis

    2015-12-01

    The composition of flower scent and the timing of emission are crucial for chemical communication between plants and their pollinators; hence, they are key traits for the characterization of pollination syndromes. In many plants, however, plants are assigned to a syndrome based on inexpensive to measure flower traits, such as color, time of flower opening, and shape. We compared day and night scents from 31 Sileneae species and tested for quantitative and semi-quantitative differences in scent among species classified a priori as diurnal or nocturnal. As most Sileneae species are not only visited by either diurnal or nocturnal animals as predicted by their syndrome, we hypothesized that, even if flower scent were preferentially emitted during the day or at night, most species also would emit some scents during the opposing periods of the day. This phenomenon would contribute to the generalized assemblage of flower visitors usually observed in Sileneae species. We found that diel variations of scent often were not congruent with the syndrome definition, but could partially be explained by taxonomy and sampling times. Most species emitted compounds with attractive potential to insects during both the night and day. Our results highlight the current opinion that syndromes are not watertight compartments evolved to exclude some flower visitors. Thus, important information may be lost when scents are collected either during day- or night-time, depending on the a priori classification of the species as diurnal or nocturnal.

  3. Seasonal asymmetry in diurnal variation of aerosol optical characteristics over Pune, western India

    NASA Astrophysics Data System (ADS)

    Pandithurai, G.; Pinker, R. T.; Devara, P. C. S.; Takamura, T.; Dani, K. K.

    2007-04-01

    There is a large day-to-day variability in aerosol optical properties due to varied meteorological conditions that exhibit different diurnal asymmetry in different synoptic seasons. Aerosol optical depth (AOD) and Ångstrom exponent (AE) measured for a period of 3 years at Pune, an urban site in western India, were analyzed to study the diurnal variation and its seasonal dependence. Mean AOD at 500 nm in the premonsoon (March-May) period was about 0.42, while in the winter (December, January, and February) it was ˜0.38. AOD departures from the daily mean showed ±20% variation (which is equivalent to AOD of 0.08) in both seasons. A systematic seasonal asymmetry in diurnal variation was found. AOD is higher in the morning and lower in the afternoon during winter, mainly because of higher relative humidities, calm winds, and associated ground-based inversions that are conducive for haze, which persists till noon. However, in premonsoon, AODs are lower in the forenoon hours and higher in the afternoon hours because of higher air temperatures, strong convection, and stronger winds raising more dust locally and transporting it from Saudi Arabia and Afghanistan regions. The difference between Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua derived AOD showed similar seasonal asymmetry in forenoon-afternoon difference in aerosol loading as observed at the experimental site.

  4. Observations of diurnal oscillations with a meteor wind radar and radiosondes in Indonesia

    NASA Astrophysics Data System (ADS)

    Tsuda, Toshitaka; Nakamura, Takuji; Shimizu, Atsushi; Yoshino, Tetsuo; Harijono, Sri Woro B.; Sribimawati, Tien; Wiryosumarto, Harsono

    1997-11-01

    We constructed a meteor wind radar in an observatory near Jakarta, Indonesia, through collaboration between Japan and Indonesia, which has been operating continuously since November 1992. Horizontal wind velocity fluctuations were determined for altitudes between 75 and 100 km with time and height resolutions of 1 hour and 4 km, respectively. We also launched radiosondes from Bandung, four times a day from November 1992 to April 1993, and obtained profiles of horizontal wind velocity and temperature at 0-35 km with a height resolution of 150 m. Further, the data collected during the Tropical Ocean and Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment (TOGA/COARE) campaign have been particularly used to investigate the horizontal variations of diurnal oscillations. Overall structure of the observed wind velocity profiles agreed well with the model diurnal winds above 20 km, with a dominant vertical wavelength of 25-30 km. However, disagreements appeared below 20 km, showing significantly larger amplitudes and complicated phase structures, which may suggest the effects of nonmigrating tides. Diurnal oscillations of the temperature in the lower atmosphere were described very well by a numerical model.

  5. Diurnal Variability of the Hydrologic Cycle and Radiative Fluxes: Comparisons Between Observation and a GCM

    NASA Technical Reports Server (NTRS)

    Lin, Xin; Randall, David A.; Fowler, Laura D.

    2000-01-01

    The simulated diurnal cycle is in many ways an ideal test bed for new physical parameterizations. The purpose of this paper is to compare observations from the Tropical Rainfall Measurement Mission, the Earth Radiation Budget Experiment, the International Satellite Cloud Climatology Project, the Clouds and the Earth's Radiant Energy System Experiment, and the Anglo-Brazilian Amazonian Climate Observation Study with the diurnal variability of the Amazonian hydrologic cycle and radiative energy budget as simulated by the Colorado State University general circulation model, and to evaluate improvements and deficiencies of the model physics. The model uses a prognostic cumulus kinetic energy (CKE) to relax the quasi-equilibrium closure of the Arakawa-Schubert cumulus parameterization. A parameter, alpha, is used to relate the CKE to the cumulus mass flux. This parameter is expected to vary with cloud depth, mean shear, and the level of convective activity, but up to now a single constant value for all cloud types has been used. The results of the present study show clearly that this approach cannot yield realistic simulations of both the diurnal cycle and the monthly mean climate state. Improved results are obtained using a version of the model in which alpha is permitted to vary with cloud depth.

  6. Diurnal Variation of Circulating Interleukin-6 in Humans: A Meta-Analysis

    PubMed Central

    Lekander, Mats; Åkerstedt, Torbjörn; Axelsson, John; Ingre, Michael

    2016-01-01

    The pleiotropic cytokine interleukin-6 (IL-6) has been proposed to contribute to circadian regulation of sleepiness by increasing in the blood at night. Earlier studies have reported diurnal variation of IL-6, but phase estimates are conflicting. We have therefore performed a meta-analysis on the diurnal variation of circulating IL-6. Studies were included if they reported IL-6 in plasma or serum recorded at least twice within 24 hours in the same individual. A systematic search resulted in the inclusion of 43 studies with 56 datasets, for a total of 1100 participants. Individual participant data were available from 4 datasets with a total of 56 participants. Mixed-effects meta-regression modelling confirmed that IL-6 varied across the day, the most conspicuous effect being a trough in the morning. These results stand in contrast to earlier findings of a peak in the evening or night, and suggest that diurnal variation should be taken into account in order to avoid confounding by time of day in studies of IL-6 in plasma or serum. PMID:27832117

  7. Diurnal patterns of the bi-directional reflectance of fresh-water ice

    NASA Technical Reports Server (NTRS)

    Leshkevich, George A.; Deering, Donald W.; Eck, Thomas F.; Ahmad, Suraiya P.

    1990-01-01

    To improve the interpretation of surface cryospheric albedo from satellite sensor data, diurnal measurements of the spectral bidirectional reflectance of a commonly found fresh water ice type were made, from which hemispherical reflectance can be derived. The purpose of this study is to document its clear-sky, bidirectional reflectance characteristics in the visible (650-670 nm) and near-infrared (810-840 nm) region, assess the diurnal nature of the reflectance, and quantify the surface anisotropy. Bidirectional reflectances of the refrozen slush ice measured show a spectral dependence and change significantly with solar zenith angle. Considerable variation occurs at each view angle and among view angles throughout the day. Although diurnal reflectance patterns were similar in both bands, magnitudes varied greatly, being highest in the visible and lowest in the near-infrared region. With the exception of peak saturated (specular) values in the forward scatter direction, bidirectional reflectance was generally highest in the morning when the surface and the illumination were most diffuse in character.

  8. Global Electric Circuit Diurnal Variation Derived from Storm Overflight and Satellite Optical Lightning Datasets

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, R. J.; Bateman, M. J.; Bailey, J. C.

    2011-01-01

    We have combined analyses of over 1000 high altitude aircraft observations of electrified clouds with diurnal lightning statistics from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) to produce an estimate of the diurnal variation in the global electric circuit. Using basic assumptions about the mean storm currents as a function of flash rate and location, and the global electric circuit, our estimate of the current in the global electric circuit matches the Carnegie curve diurnal variation to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Mean contributions to the global electric circuit from land and ocean thunderstorms are 1.1 kA (land) and 0.7 kA (ocean). Contributions to the global electric circuit from ESCs are 0.22 kA for ocean storms and 0.04 kA for land storms. Using our analysis, the mean total conduction current for the global electric circuit is 2.0 kA.

  9. Quantifying Diurnal Cloud Radiative Effects by Cloud Type in the Tropical Western Pacific

    SciTech Connect

    Burleyson, Casey D.; Long, Charles N.; Comstock, Jennifer M.

    2015-06-01

    Cloud radiative effects are examined using long-term datasets collected at the three Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facilities in the tropical western Pacific. We quantify the surface radiation budget, cloud populations, and cloud radiative effects by partitioning the data by cloud type, time of day, and as a function of large scale modes of variability such as El Niño Southern Oscillation (ENSO) phase and wet/dry seasons at Darwin. The novel facet of our analysis is that we break aggregate cloud radiative effects down by cloud type across the diurnal cycle. The Nauru cloud populations and subsequently the surface radiation budget are strongly impacted by ENSO variability whereas the cloud populations over Manus only shift slightly in response to changes in ENSO phase. The Darwin site exhibits large seasonal monsoon related variations. We show that while deeper convective clouds have a strong conditional influence on the radiation reaching the surface, their limited frequency reduces their aggregate radiative impact. The largest source of shortwave cloud radiative effects at all three sites comes from low clouds. We use the observations to demonstrate that potential model biases in the amplitude of the diurnal cycle and mean cloud frequency would lead to larger errors in the surface energy budget compared to biases in the timing of the diurnal cycle of cloud frequency. Our results provide solid benchmarks to evaluate model simulations of cloud radiative effects in the tropics.

  10. Associations Between Jet Lag and Cortisol Diurnal Rhythms After Domestic Travel

    PubMed Central

    Doane, Leah D.; Kremen, William S.; Eaves, Lindon J.; Eisen, Seth A.; Hauger, Richard; Hellhammer, Dirk; Levine, Seymour; Lupien, Sonia; Lyons, Michael J.; Mendoza, Sally; Prom-Wormley, Elizabeth; Xian, Hong; York, Timothy P.; Franz, Carol E.; Jacobson, Kristen C.

    2011-01-01

    Objective Millions of adults in the United States travel abruptly across time zones each year. Nevertheless, the impact of traveling over relatively short distances (across 3 or fewer time zones) on diurnal patterning of typical physiological response patterns has yet to be studied in a large, epidemiological sample. Design The current research focuses on 764 middle-aged men comparing variations in diurnal cortisol regulation based on number of time zones traveled eastward or westward the day before. Main Outcome Measure Participants provided samples of salivary cortisol at waking, 30-min postwaking, 10 a.m., 3 p.m., and bedtime. Results Eastward travel was associated with a steeper salivary cortisol awakening response ( p < .01) and lower peak (PEAK) levels of salivary cortisol the next morning ( p < .05). Westward travel was associated with lower peak levels of cortisol the next morning ( p < .05). Effect sizes for these differences ranged from Cohen’s d = .29 to .47. Differences were not present for 2 days in their home environment. Conclusions The results provide evidence that traveling across time zones is associated with diurnal cortisol regulation and should be studied further to understand the subsequent impacts on health and well-being in large national samples. PMID:20230083

  11. QBO Generated Inter-annual Variations of the Diurnal Tide in the Mesosphere

    NASA Technical Reports Server (NTRS)

    Mayr, Hans G.; Mengel, John G.

    2004-01-01

    We report results from a study with the Numerical Spectral Model (NSM), which produces in the mesosphere significant inter-annual variations in the diurnal tide. Applying Hines Doppler Spread Parameterization (DPS), small-scale gravity waves (GW) drive the Quasi-biennial Oscillation (QBO) and Semi-annual Oscillation (SAO). With a GW source that peaks at the equator and is taken to be isotropic and independent of season, the NSM generates near the equator a QBO with variable periods around 27 months and zonal wind amplitudes close to 20 m / s at 30 Ism. As reported earlier, the NSM reproduces the observed equinoctial maxima in the diurnal tide at altitudes around 95 km. In the present paper it is shown that the QBO modulates the tide such that the seasonal amplitude maxima can vary from one year to another by as much as 30%. Since the period of the QBO is variable, its phase relative to the seasonal cycle changes. The magnitude of the QBO modulation of the tide thus varies considerably as our long-term model simulation shows. To shed light on the underlying mechanism, the relative importance of the linearized advection terms are discussed that involve the meridional and vertical winds of the diurnal tide.

  12. Altered diurnal pattern of steroid hormones in relation to various behaviors, external factors and pathologies: A review.

    PubMed

    Collomp, K; Baillot, A; Forget, H; Coquerel, A; Rieth, N; Vibarel-Rebot, N

    2016-10-01

    The adrenal and gonadal stress steroids [i.e., cortisol, testosterone and dehydroepiandrosterone (DHEA)] have gathered considerable attention in the last few decades due to their very broad physiological and psychological actions. Their diurnal patterns have become a particular focus following new data implicating altered diurnal hormone patterns in various endocrine, behavioral and cardiovascular risk profiles. In this review of the current literature, we present a brief overview of the altered diurnal patterns of these hormones that may occur in relation to chronic stress, nutritional behaviors, physical exercise, drugs and sleep deprivation/shift. We also present data on the altered diurnal hormone patterns implicated in cardiometabolic and psychiatric/neurologic diseases, cancer and other complex pathologies. We consider the occasionally discrepant results of the studies, and summarize the current knowledge in this new field of interest, underlining the potential effects on both biological and psychological functioning, and assess the implications of these effects. Last, we conclude with some practical considerations and perspectives.

  13. Are rainforest owl monkeys cathemeral? Diurnal activity of black-headed owl monkeys, Aotus nigriceps, at Manu Biosphere Reserve, Peru.

    PubMed

    Khimji, Shenaz N; Donati, Giuseppe

    2014-01-01

    Members of the genus Aotus are traditionally considered strictly nocturnal, however, in recent years cathemeral habits have been described in a single species of owl monkey, Aotus azarai, which occur in the highly seasonal habitat of the Argentinean Chaco. This finding raises the question as to whether other species of Aotus exhibit cathemeral activity in less seasonal habitats. In this study, we observed the diurnal activity of one group of A. nigriceps living in the Manu Biosphere Reserve, Peru over 65 days. The data collected indicate that A. nigriceps has only sporadic diurnal bouts of activity. In addition, nocturnal luminosity of the previous night, rainfall, and temperature did not correlate with the minor diurnal activity exhibited. This suggests that for A. nigriceps the potential costs of shifting to diurnality may outweigh its prospective advantages in this rainforest environment.

  14. Diurnal and Seasonal Trends in Canopy Transpiration and Conductance of Pristine Forest Types in Belize, Central America

    NASA Technical Reports Server (NTRS)

    Zimmermann, R.; Oren, R.; Billings, S.; Muller-Ezards, C.; Schaaff, C.; Strohmeier, P.; Obermaier, E.

    1994-01-01

    Five semi-deciduous broadleaf forest types growing over tropical karst in Belize, Central America, were monitored for three years to study diurnal and seasonal changes of transpiration and micro-meteorologic conditions.

  15. Developmental histories of perceived racial discrimination and diurnal cortisol profiles in adulthood: A 20-year prospective study.

    PubMed

    Adam, Emma K; Heissel, Jennifer A; Zeiders, Katharine H; Richeson, Jennifer A; Ross, Emily C; Ehrlich, Katherine B; Levy, Dorainne J; Kemeny, Margaret; Brodish, Amanda B; Malanchuk, Oksana; Peck, Stephen C; Fuller-Rowell, Thomas E; Eccles, Jacquelynne S

    2015-12-01

    Perceived racial discrimination (PRD) has been associated with altered diurnal cortisol rhythms in past cross-sectional research. We investigate whether developmental histories of PRD, assessed prospectively, are associated with adult diurnal cortisol profiles. One-hundred and twelve (N=50 Black, N=62 White) adults from the Maryland Adolescent Development in Context Study provided saliva samples in adulthood (at approximately age 32 years) at waking, 30min after waking, and at bedtime for 7 days. Diurnal cortisol measures were calculated, including waking cortisol levels, diurnal cortisol slopes, the cortisol awakening response (CAR), and average daily cortisol (AUC). These cortisol outcomes were predicted from measures of PRD obtained over a 20-year period beginning when individuals were in 7th grade (approximately age 12). Greater average PRD measured across the 20-year period predicted flatter adult diurnal cortisol slopes for both Black and White adults, and a lower CAR. Greater average PRD also predicted lower waking cortisol for Black, but not White adults. PRD experiences in adolescence accounted for many of these effects. When adolescent and young adult PRD are entered together predicting cortisol outcomes, PRD experiences in adolescence (but not young adulthood) significantly predicted flatter diurnal cortisol slopes for both Black and White adults. Adolescent, but not young adult PRD, also significantly predicted lower waking and lower average cortisol for Black adults. Young adult PRD was, however, a stronger predictor of the CAR, predicting a marginally lower CAR for Whites, and a significantly larger CAR for Blacks. Effects were robust to controlling for covariates including health behaviors, depression, income and parent education levels. PRD experiences interacted with parent education and income to predict aspects of the diurnal cortisol rhythm. Although these results suggest PRD influences on cortisol for both Blacks and Whites, the key findings

  16. A day-centered approach to modeling cortisol: Diurnal cortisol profiles and their associations among U.S. adults

    PubMed Central

    Dmitrieva, Natalia O.; Almeida, David M.; Dmitrieva, Julia; Loken, Eric; Pieper, Carl F.

    2013-01-01

    Summary Diurnal cortisol is a marker of HPA-axis activity that may be one of the biological mechanisms linking stressors to age-related health declines. The current study identified day-centered profiles of diurnal cortisol among 1,101 adults living in the United States. Participants took part in up to four consecutive days of salivary cortisol collection, assessed at waking, 30 minutes post-waking, before lunch, and before bedtime. Growth Mixture Modeling with latent time basis was used to estimate common within-day trajectories of diurnal cortisol among 2,894 cortisol days. The 3-class solution provided the best model fit, showing that the majority of study days (73%) were characterized by a Normative cortisol pattern, with a robust cortisol awakening response (CAR), a steep negative diurnal slope, coupled with low awakening and bedtime levels. Relative to this profile, diurnal cortisol on the remainder of days appeared either Elevated throughout the day (20% of days) or Flattened (7% of days). Relative to the Normative trajectory, the Elevated trajectory was distinguished by a higher morning cortisol level, whereas the Flattened trajectory was characterized by a high bedtime level, with weaker CAR and diurnal slope parameters. Relative to the Normative profile, Elevated profile membership was associated with older age and cigarette smoking. Greater likelihood of the Flattened cortisol pattern was observed among participants who were older, male, smoked cigarettes, used medications that are known to affect cortisol output, and reported poorer health. The current study demonstrates the value of a day-centered Growth Mixture Modeling approach to the study of diurnal cortisol, showing that deviations from the classic robust rhythm of diurnal cortisol are associated with older age, male sex, use of medications previously shown to affect cortisol levels, poorer health behaviors, and poorer self-reported health. PMID:23770247

  17. Diurnal Lightning Distributions as Observed by the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS)

    NASA Technical Reports Server (NTRS)

    Bailey, Jeff C.; Blakeslee, Richard J.; Buechler, Dennis E.; Christian, Hugh J.

    2007-01-01

    Data obtained from the Optical Transient Detector (April 1995 to March 2000) and the Lightning Imaging Sensor (December 1997 to December 2005) satellites (70 and 35 inclination low earth orbits, respectively) are used to statistically determine the number of flashes in the annual and seasonal diurnal cycle as a function of local and universal time. The data are further subdivided by season, land versus ocean, northern versus southern hemisphere, and other spatial (e.g., continents) and temporal (e.g., time of peak diurnal amplitude) categories. The data include corrections for detection efficiency and instrument view time. Continental results display strong diurnal variation, with a lightning peak in the late afternoon and a minimum in late morning. In regions of the world dominated by large mesoscale convective systems the peak in the diurnal curve shifts toward late evening or early morning hours. The maximum diurnal flash rate occurs in June-August, corresponding to the Northern Hemisphere summer, while the minimum occurs in December-February. Summer lightning dominates over winter activity and springtime lightning dominates over autumn activity at most continental locations. This latter behavior occurs especially strongly over the Amazon region in South America in September-November. Oceanic lightning activity in winter and autumn tends to exceed that in summer and spring. Global lightning is well correlated in phase but not in amplitude with the Carnegie curve. The diurnal flash rate varies about 4-35 percent about the mean, while the Carnegie curve varies around 4-15 percent.

  18. Influence of diurnal photosynthetic activity on the morphology, structure, and thermal properties of normal and waxy barley starch.

    PubMed

    Goldstein, Avi; Annor, George; Vamadevan, Varatharajan; Tetlow, Ian; Kirkensgaard, Jacob J K; Mortensen, Kell; Blennow, Andreas; Hebelstrup, Kim H; Bertoft, Eric

    2017-05-01

    This study investigated the influence of diurnal photosynthetic activity on the morphology, molecular composition, crystallinity, and gelatinization properties of normal barley starch (NBS) and waxy barley starch (WBS) granules from plants cultivated in a greenhouse under normal diurnal (16h light) or constant light photosynthetic conditions. Growth rings were observed in all starch samples regardless of lighting conditions. The size distribution of whole and debranched WBS analyzed by gel-permeation chromatography did not appear to be influenced by the different lighting regimes, however, a greater relative crystallinity measured by wide-angle X-ray scattering and greater crystalline quality as judged by differential scanning calorimetry was observed under the diurnal lighting regime. NBS cultivated under the diurnal photosynthetic lighting regime displayed lower amylose content (18.7%), and shorter amylose chains than its counterpart grown under constant light. Although the relative crystallinity of NBS was not influenced by lighting conditions, lower onset, peak, and completion gelatinization temperatures were observed in diurnally grown NBS compared to constant light conditions. It is concluded that normal barley starch is less influenced by the diurnal photosynthetic lighting regime than amylose-free barley starch suggesting a role of amylose to prevent structural disorder and increase starch granule robustness against environmental cues.

  19. Effect of Static and Dynamic Stretching on the Diurnal Variations of Jump Performance in Soccer Players

    PubMed Central

    Chtourou, Hamdi; Aloui, Asma; Hammouda, Omar; Chaouachi, Anis; Chamari, Karim; Souissi, Nizar

    2013-01-01

    Purpose The present study addressed the lack of data on the effect of different types of stretching on diurnal variations in vertical jump height - i.e., squat-jump (SJ) and countermovement-jump (CMJ). We hypothesized that dynamic stretching could affect the diurnal variations of jump height by producing a greater increase in short-term maximal performance in the morning than the evening through increasing core temperature at this time-of-day. Methods Twenty male soccer players (age, 18.6±1.3 yrs; height, 174.6±3.8 cm; body-mass, 71.1±8.6 kg; mean ± SD) completed the SJ and CMJ tests either after static stretching, dynamic stretching or no-stretching protocols at two times of day, 07:00 h and 17:00 h, with a minimum of 48 hours between testing sessions. One minute after warming-up for 5 minutes by light jogging and performing one of the three stretching protocols (i.e., static stretching, dynamic stretching or no-stretching) for 8 minutes, each subject completed the SJ and CMJ tests. Jumping heights were recorded and analyzed using a two-way analysis of variance with repeated measures (3 [stretching]×2 [time-of-day]). Results The SJ and CMJ heights were significantly higher at 17:00 than 07:00 h (p<0.01) after the no-stretching protocol. These daily variations disappeared (i.e., the diurnal gain decreased from 4.2±2.81% (p<0.01) to 1.81±4.39% (not-significant) for SJ and from 3.99±3.43% (p<0.01) to 1.51±3.83% (not-significant) for CMJ) after dynamic stretching due to greater increases in SJ and CMJ heights in the morning than the evening (8.4±6.36% vs. 4.4±2.64%, p<0.05 for SJ and 10.61±5.49% vs. 6.03±3.14%, p<0.05 for CMJ). However, no significant effect of static stretching on the diurnal variations of SJ and CMJ heights was observed. Conclusion Dynamic stretching affects the typical diurnal variations of SJ and CMJ and helps to counteract the lower morning values in vertical jump height. PMID:23940589

  20. Influence of Observed Diurnal Cycles of Aerosol Optical Depth on Aerosol Direct Radiative Effect

    NASA Technical Reports Server (NTRS)

    Arola, A.; Eck, T. F.; Huttunen, J.; Lehtinen, K. E. J.; Lindfors, A. V.; Myhre, G.; Smirinov, A.; Tripathi, S. N.; Yu, H.

    2013-01-01

    The diurnal variability of aerosol optical depth (AOD) can be significant, depending on location and dominant aerosol type. However, these diurnal cycles have rarely been taken into account in measurement-based estimates of aerosol direct radiative forcing (ADRF) or aerosol direct radiative effect (ADRE). The objective of our study was to estimate the influence of diurnal aerosol variability at the top of the atmosphere ADRE estimates. By including all the possible AERONET sites, we wanted to assess the influence on global ADRE estimates. While focusing also in more detail on some selected sites of strongest impact, our goal was to also see the possible impact regionally.We calculated ADRE with different assumptions about the daily AOD variability: taking the observed daily AOD cycle into account and assuming diurnally constant AOD. Moreover, we estimated the corresponding differences in ADREs, if the single AOD value for the daily mean was taken from the the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra or Aqua overpass times, instead of accounting for the true observed daily variability. The mean impact of diurnal AOD variability on 24 h ADRE estimates, averaged over all AERONET sites, was rather small and it was relatively small even for the cases when AOD was chosen to correspond to the Terra or Aqua overpass time. This was true on average over all AERONET sites, while clearly there can be much stronger impact in individual sites. Examples of some selected sites demonstrated that the strongest observed AOD variability (the strongest morning afternoon contrast) does not typically result in a significant impact on 24 h ADRE. In those cases, the morning and afternoon AOD patterns are opposite and thus the impact on 24 h ADRE, when integrated over all solar zenith angles, is reduced. The most significant effect on daily ADRE was induced by AOD cycles with either maximum or minimum AOD close to local noon. In these cases, the impact on 24 h ADRE was

  1. Aerobic Toluene Degraders in the Rhizosphere of a Constructed Wetland Model Show Diurnal Polyhydroxyalkanoate Metabolism

    PubMed Central

    Lünsmann, Vanessa; Kappelmeyer, Uwe; Taubert, Anja; Nijenhuis, Ivonne; von Bergen, Martin; Müller, Jochen A.; Jehmlich, Nico

    2016-01-01

    ABSTRACT Constructed wetlands (CWs) are successfully applied for the treatment of waters contaminated with aromatic compounds. In these systems, plants provide oxygen and root exudates to the rhizosphere and thereby stimulate microbial degradation processes. Root exudation of oxygen and organic compounds depends on photosynthetic activity and thus may show day-night fluctuations. While diurnal changes in CW effluent composition have been observed, information on respective fluctuations of bacterial activity are scarce. We investigated microbial processes in a CW model system treating toluene-contaminated water which showed diurnal oscillations of oxygen concentrations using metaproteomics. Quantitative real-time PCR was applied to assess diurnal expression patterns of genes involved in aerobic and anaerobic toluene degradation. We observed stable aerobic toluene turnover by Burkholderiales during the day and night. Polyhydroxyalkanoate synthesis was upregulated in these bacteria during the day, suggesting that they additionally feed on organic root exudates while reutilizing the stored carbon compounds during the night via the glyoxylate cycle. Although mRNA copies encoding the anaerobic enzyme benzylsuccinate synthase (bssA) were relatively abundant and increased slightly at night, the corresponding protein could not be detected in the CW model system. Our study provides insights into diurnal patterns of microbial processes occurring in the rhizosphere of an aquatic ecosystem. IMPORTANCE Constructed wetlands are a well-established and cost-efficient option for the bioremediation of contaminated waters. While it is commonly accepted knowledge that the function of CWs is determined by the interplay of plants and microorganisms, the detailed molecular processes are considered a black box. Here, we used a well-characterized CW model system treating toluene-contaminated water to investigate the microbial processes influenced by diurnal plant root exudation. Our results

  2. Diurnal resting in brown lemurs in a dry deciduous forest, northwestern Madagascar: implications for seasonal thermoregulation.

    PubMed

    Sato, Hiroki

    2012-07-01

    Decreased activity has been reported in both nocturnal and diurnal primates during the prolonged dry season in western Madagascar, and this has been interpreted as a reaction to the severe environment, with its food scarcity and/or thermal stress. Several day-active lemurs rest more as trees defoliate, although the reason for this is unclear. To understand the mechanism underpinning the diurnal resting of lemurs in seasonal deciduous forests, I observed common brown lemurs (Eulemur fulvus fulvus) for one year in Ankarafantsika National Park, northwestern Madagascar. In Ankarafantsika, despite high fruit availability during the dry season, brown lemurs are known to engage in diurnal resting. To examine the effects of thermal factors and defoliation on lemur inactivity, I recorded the activity of a troop at 1 min intervals, hourly ambient temperature, daily rainfall, and weather during observations (06:00-18:00). I quantified the amount of leaves biweekly for 680 trees. I tested correlations between percentages of resting time and each factor across hours during the day and across seasons. During the rainy season, resting time did not differ between sunny and cloudy days, and lemurs were active throughout the daytime. At the hourly level during the dry season, lemurs rested exclusively at midday, apparently at peak sunlight intensity rather than at peak ambient temperature. At seasonal level, percentages of total resting time from 08:00 to 16:00 were greater during dry season (81.9%) than during rainy season (62.6%), and percentages increased as ambient temperatures increased. Defoliation was related to seasonal decrease in weekly rainfall, which served as an index of water retained in the forest. Defoliation probably reflected aridification as well as the penetration of sunlight into the forest. Diurnal resting increased as both the amount of leaves and weekly rainfall decreased seasonally. These results suggest that heat stress under dry conditions may promote

  3. Diurnal variation in rates of calcification and carbonate sediment dissolution in Florida Bay

    USGS Publications Warehouse

    Yates, K.K.; Halley, R.B.

    2006-01-01

    Water quality and circulation in Florida Bay (a shallow, subtropical estuary in south Florida) are highly dependent upon the development and evolution of carbonate mud banks distributed throughout the Bay. Predicting the effect of natural and anthropogenic perturbations on carbonate sedimentation requires an understanding of annual, seasonal, and daily variations in the biogenic and inorganic processes affecting carbonate sediment precipitation and dissolution. In this study, net calcification rates were measured over diurnal cycles on 27 d during summer and winter from 1999 to 2003 on mud banks and four representative substrate types located within basins between mud banks. Substrate types that were measured in basins include seagrass beds of sparse and intermediate density Thalassia sp., mud bottom, and hard bottom communities. Changes in total alkalinity were used as a proxy for calcification and dissolution. On 22 d (81%), diurnal variation in rates of net calcification was observed. The highest rates of net carbonate sediment production (or lowest rates of net dissolution) generally occurred during daylight hours and ranged from 2.900 to -0.410 g CaCO3 m-2 d-1. The lowest rates of carbonate sediment production (or net sediment dissolution) occurred at night and ranged from 0.210 to -1.900 g CaCO3 m -2 night-1. During typical diurnal cycles, dissolution during the night consumed an average of 29% of sediment produced during the day on banks and 68% of sediment produced during the day in basins. Net sediment dissolution also occurred during daylight, but only when there was total cloud cover, high turbidity, or hypersalinity. Diurnal variation in calcification and dissolution in surface waters and surface sediments of Florida Bay is linked to cycling of carbon dioxide through photosynthesis and respiration. Estimation of long-term sediment accumulation rates from diurnal rates of carbonate sediment production measured in this study indicates an overall average

  4. Developing and evaluating a synoptic and diurnally varying time series of global fire emissions

    NASA Astrophysics Data System (ADS)

    Mu, M.; Randerson, J. T.; Giglio, L.; van der Werf, G. R.; Hyer, E.; Prins, E.

    2008-12-01

    To assess how recent changes in fire activity and burned area influence climate and human health, we need to improve our understanding of fire emissions. Information on synoptic and diurnal time scales may be particularly relevant for capturing interactions between climate drivers of fire activity and atmospheric transport of particulate and trace gas emissions. Developing emissions time series at this high temporal resolution requires combining active fire products with burned area information that is typically available only at monthly or annual intervals. Here we used several different active fire products from MODIS and GOES to distribute monthly fire emissions from Global Fire Emissions Database version 2 (GFEDv2) at a 3-hour time step. This process required several steps. First, we used the 8-day overpass corrected climate modeling grid active fires from MODIS AQUA and TERRA to distribute emissions during 8-day intervals within a year. In a second step we distributed emissions day by day within each 8-day interval using raw active fire detections from MODIS. In a final step we used GOES active fire observations to construct mean diurnal cycles for different vegetation types and latitude zones. These mean cycles were then applied to the daily emissions. The results show reasonable agreement of daily fire activity as compared with GOES, VIRS, and ATSR active fire products. We constructed mean diurnal cycles from GOES observations for three different land types: forest, shrublands and savannas, and grasses and crops in different latitude zones. We found that maximum fire activity occurred in the early afternoon 12:00-3:00 PM and minimum fire activity occurred at night from 00:00 to 6:00 AM. The diurnal cycles varied substantially in different land cover types and regions with boreal forest fires, for example, showing substantially more burning in late afternoon and night than fires in grassland or cropland areas. Fires in shrublands and savannas and grasslands

  5. What the diurnal cycle of precipitation tells us about land-atmosphere coupling strength

    NASA Astrophysics Data System (ADS)

    Ferguson, Craig; Song, Hyojong; Roundy, Joshua

    2015-04-01

    The key attributes of a coupled forecast model are the coupling strengths between the land-atmosphere and ocean-atmosphere schemes. If a model cannot skillfully capture the diurnal cycle of clouds and precipitation, then it likely cannot be expected to yield accurate long-term climate projections. The seasonal drought forecast skill shortfalls of the U.S. NCEP Coupled Forecast System Version 2 (CFSv2) have been directly linked to its unrealistically strong land-atmosphere coupling strength. Most models can be similarly categorized, which is to say, sensitivity to the land physics (i.e., soil moisture constraints on evapotranspiration) is too strong. In nature, the land signal: noise ratio appears to be at a much lower value. Diagnosing land-atmosphere coupling strength requires at a minimum: surface soil moisture state, surface turbulent heat fluxes, and atmospheric moisture and instability. Full-on diagnosis would entail hacking into the code and inserting a number of tracers. This study addresses the question: What if, given the soil wetness anomaly, model biases in coupling sign and/or strength could be diagnosed from phase shifts in the diurnal precipitation frequency cycle? We use 34-years of output from the North American Regional Reanalysis (NARR) and North American Land Data Assimilation System Phase 2 (NLDAS-2) to investigate the variation in diurnal precipitation frequency cycle between so-called "wet-advantage" and "dry-advantage" coupling regimes over the U.S. southern Great Plains. Wet-advantage occurs when the atmospheric state is closer to the wet adiabatic rate and convection is triggered by a strong increase in the moist static energy from the surface. In contrast, dry-advantage occurs when the atmosphere is drier and the temperature profile is close to the dry adiabatic lapse rate, which favors convection over areas of large boundary layer growth due to high sensible heat fluxes at the surface. We find that there is a significant difference in the

  6. Diurnal variation in temperature, mental and physical performance, and tasks specifically related to football (soccer).

    PubMed

    Reilly, Thomas; Atkinson, Greg; Edwards, Ben; Waterhouse, Jim; Farrelly, Kelly; Fairhurst, Emma

    2007-01-01

    Football (soccer) training and matches are scheduled at different times throughout the day. Association football involves a variety of fitness components as well as psychomotor and game-related cognitive skills. The purpose of the present research, consisting of two separate studies, was to determine whether game-related skills varied with time of day in phase with global markers of both performance and the body clock. In the first study, eight diurnally active male association football players (19.1+/-1.9 yrs of age; mean+/-SD) with 10.8+/-2.1 yrs playing experience participated. Measurements were made on different days at 08:00, 12:00, 16:00, and 20:00 h in a counterbalanced manner. Time-of-day changes in intra-aural temperature (used as a marker of the body clock), grip strength, reaction times, flexibility (markers of aspects of performance), juggling and dribbling tasks, and wall-volley test (football-specific skills) were compared. Significant (repeated measures analysis of variance, ANOVA) diurnal variations were found for body temperature (p<0.0005), choice reaction time (p<0.05), self-rated alertness (p<0.0005), fatigue (p<0.05), forward (sit-and-reach) flexibility (p<0.02), and right-hand grip strength (p<0.02), but not left-hand grip strength (p=0.40) nor whole-body (stand-and-reach) flexibility (p=0.07). Alertness was highest and fatigue lowest at 20:00 h. Football-specific skills of juggling performance showed significant diurnal variation (p<0.05, peak at 16:00 h), whereas performance on the wall-volley test tended to peak at 20:00 h and dribbling showed no time-of-day effect (p=0.55). In a second study, eight diurnally active subjects (23.0+/-0.7 yrs of age) completed five test sessions, at the same times as in the first study but with a second session at 08:00 h. Test-re-test comparisons at 08:00 h for all components indicated good reliability. Intra-aural temperature showed a significant time-of-day effect (p<0.001) with mean temperature at 16:00 h

  7. Chronotype, sleep loss, and diurnal pattern of salivary cortisol in a simulated daylong driving.

    PubMed

    Oginska, Halszka; Fafrowicz, Magdalena; Golonka, Krystyna; Marek, Tadeusz; Mojsa-Kaja, Justyna; Tucholska, Kinga

    2010-07-01

    The study focused on chronotype-related differences in subjective load assessment, sleepiness, and salivary cortisol pattern in subjects performing daylong simulated driving. Individual differences in work stress appraisal and psychobiological cost of prolonged load seem to be of importance in view of expanding compressed working time schedules. Twenty-one healthy, male volunteers (mean +/- SD: 27.9 +/- 4.9 yrs) were required to stay in semiconstant routine conditions. They performed four sessions (each lasting approximately 2.5 h) of simulated driving, i.e., completed chosen tasks from computer driving games. Saliva samples were collected after each driving session, i.e., at 10:00-11:00, 14:00-15:00, 18:00-19:00, and 22:00-23:00 h as well as 10-30 min after waking (between 05:00 and 06:00 h) and at bedtime (after 00:00 h). Two subgroups of subjects were distinguished on the basis of the Chronotype Questionnaire: morning (M)- and evening (E)-oriented types. Subjective data on sleep need, sleeping time preferences, sleeping problems, and the details of the preceding night were investigated by questionnaire. Subjective measures of task load (NASA Task Load Index [NASA-TLX]), activation (Thayer's Activation-Deactivation Adjective Check List [AD ACL]), and sleepiness (Karolinska Sleepiness Scale [KSS]) were applied at times of saliva samples collection. M- and E-oriented types differed significantly as to their ideal sleep length (6 h 54 min +/- 44 versus 8 h 13 min +/- 50 min), preferred sleep timing (midpoint at 03:19 versus 04:26), and sleep index, i.e., 'real-to-ideal' sleep ratio, before the experimental day (0.88 versus 0.67). Sleep deficit proved to be integrated with eveningness. M and E types exhibited similar diurnal profiles of energy, tiredness, tension, and calmness assessed by AD ACL, but E types estimated higher their workload (NASA-TLX) and sleepiness (KSS). M types exhibited a trend of higher mean cortisol levels than E types (F = 4.192, p < .056) and

  8. Mountain Tropical Rainfall: Evidence of Phase-Locking between the Diurnal, Annual and Interannual Cycles in the Andes of Colombia

    NASA Astrophysics Data System (ADS)

    Poveda, G.; Bedoya, M.; Aristizábal, E.

    2015-12-01

    We study the diurnal cycle of rainfall using 15-min data from 15 raingauges located along two neighboring valleys of the Central Andes of Colombia, quantifying its long-term behavior (1998-2008), and its variability at annual and interannual (ENSO) timescales. The long-term mean annual cycle is characterized by the well-known bimodal regime, with two seasons of high rainfall during April-May and September-November, owing to the meridional oscillation of the Inter-Tropical Convergence Zone, plus other concomitant mechanisms. The long-term mean diurnal cycle of rainfall exhibits a seemingly bimodal behavior, with peak values during the afternoon (15:00 to 17:00 LST), another peak around midnight (23:00 to 02:00 LST), and minimum values from 07:00 to 10:00 LST. But a detailed examination shows that the diurnal cycle is mostly unimodal throughout the year, with a seasonally-dependent shifting phase. From May to September rainfall maximum occurs between 22:00 and 02:00 LST, while from October to April it occurs from 13:00 to 16:00 LST (see Figure 1). During short transition periods, a bimodal diurnal cycle can be observed. Our results evidence the existence of phase-locking between the diurnal and annual cycles of rainfall. At inter-annual (ENSO) timescales, the amplitude of the diurnal cycle is reduced (augmented) during El Niño (La Niña), and the phase of the diurnal cycle remains shifting between the same hours and seasons during normal, El Niño and La Niña years, which in turn evidences phase-locking between the diurnal, annual and interannual cycles of rainfall. We provide a detailed explanation of the physical mechanisms involved in such phase-locking among those three oscillators. Figure 1. Seasonal march (y-axis) of the diurnal cycle of rainfall at selected raingauges. The diurnal cycle is defined from 07:00 to 07:00 LST (x-axis). Interpolated iso-lines represent percent of total daily rainfall at each hour, with the color scale at the bottom.

  9. New fire diurnal cycle characterizations to improve fire radiative energy assessments made from low-Earth orbit satellites sampling

    NASA Astrophysics Data System (ADS)

    Andela, N.; Kaiser, J. W.; van der Werf, G. R.; Wooster, M. J.

    2015-03-01

    Accurate near real time fire emissions estimates are required for air quality forecasts. To date, most approaches are based on satellite-derived estimates of fire radiative power (FRP), which can be converted to fire radiative energy (FRE) which is directly related to fire emissions. Uncertainties in these FRE estimations are often substantial. This is for a large part because the most often used low-Earth orbit satellite-based instruments like the MODerate-resolution Imaging Spectroradiometer (MODIS) have a relatively poor sampling of the usually pronounced fire diurnal cycle. In this paper we explore the spatial variation of this fire diurnal cycle and its drivers. Specifically, we assess how representing the fire diurnal cycle affects FRP and FRE estimations when using data collected at MODIS overpasses. Using data assimilation we explored three different methods to estimate hourly FRE, based on an incremental sophistication of parameterizing the fire diurnal cycle. We sampled data from the geostationary Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) at MODIS detection opportunities to drive the three approaches. The full SEVIRI time-series, providing full coverage of the diurnal cycle, were used to evaluate the results. Our study period comprised three years (2010-2012), and we focussed on Africa and the Mediterranean basin to avoid the use of potentially lower quality SEVIRI data obtained at very far off-nadir view angles. We found that the fire diurnal cycle varies substantially over the study region, and depends on both fuel and weather conditions. For example, more "intense" fires characterized by a fire diurnal cycle with high peak fire activity, long duration over the day, and with nighttime fire activity are most common in areas of large fire size (i.e., large burned area per fire event). These areas are most prevalent in relatively arid regions. Ignoring the fire diurnal cycle as done currently in some approaches caused structural

  10. Diurnal odor, ammonia, hydrogen sulfide, and carbon dioxide emission profiles of confined swine grower/finisher rooms.

    PubMed

    Sun, Gang; Guo, Huiqing; Peterson, Jonathan; Predicala, Bernardo; Laguë, Claude

    2008-11-01

    The objective of this study was to obtain diurnal variation profiles of odor and gas (ammonia [NH3], hydrogen sulfide [H2S], carbon dioxide [CO2]) concentrations and emission rate (OGCER) from confined swine grower/ finisher rooms under three typical weather conditions (warm, mild, and cold weather) in a year. Two grower/ finisher rooms, one with a fully slatted floor and the other with partially slatted floors, were measured for 2 consecutive days under each weather condition. The results revealed that the diurnal OGCER in the room with a fully slatted floor was 9.2-39.4% higher than that with a partially slatted floor; however, no significant differences in the diurnal OGCER were found between these two rooms, except for the NH3 concentrations in August, the NH3 and H2S concentrations and emissions in October, and odor concentrations and emissions in February (p > 0.05). The OGCER variations presented different diurnal patterns as affected by time of day, season, type of floor, ventilation rate, animal growth cycles, in-house manure storage, and weather conditions. Significant diurnal fluctuations in the OGCER (except for the odor concentrations and H2S emissions) were observed in August (p < 0.05); all of the gas emissions in October and the CO2 concentrations and emissions in February also showed significant diurnal variations (p < 0.05). These significant diurnal variations indicated that the OGCER during different periods of a day should be monitored when quantifying OGCER concentrations and emissions; for example, source emission data used in air dispersion modeling to decrease the great incertitude of setback determination using randomly measured data.

  11. Wheel running improves REM sleep and attenuates stress-induced flattening of diurnal rhythms in F344 rats.

    PubMed

    Thompson, Robert S; Roller, Rachel; Greenwood, Benjamin N; Fleshner, Monika

    2016-05-01

    Regular physical activity produces resistance to the negative health consequences of stressor exposure. One way that exercise may confer stress resistance is by reducing the impact of stress on diurnal rhythms and sleep; disruptions of which contribute to stress-related disease including mood disorders. Given the link between diurnal rhythm disruptions and stress-related disorders and that exercise both promotes stress resistance and is a powerful non-photic biological entrainment cue, we tested if wheel running could reduce stress-induced disruptions of sleep/wake behavior and diurnal rhythms. Adult, male F344 rats with or without access to running wheels were instrumented for biotelemetric recording of diurnal rhythms of locomotor activity, heart rate, core body temperature (CBT), and sleep (i.e. REM, NREM, and WAKE) in the presence of a 12 h light/dark cycle. Following 6 weeks of sedentary or exercise conditions, rats were exposed to an acute stressor known to disrupt diurnal rhythms and produce behaviors associated with mood disorders. Prior to stressor exposure, exercise rats had higher CBT, more locomotor activity during the dark cycle, and greater %REM during the light cycle relative to sedentary rats. NREM and REM sleep were consolidated immediately following peak running to a greater extent in exercise, compared to sedentary rats. In response to stressor exposure, exercise rats expressed higher stress-induced hyperthermia than sedentary rats. Stressor exposure disrupted diurnal rhythms in sedentary rats; and wheel running reduced these effects. Improvements in sleep and reduced diurnal rhythm disruptions following stress could contribute to the health promoting and stress protective effects of exercise.

  12. Characterisation of seasonal development of two main crops describing diurnal courses

    NASA Astrophysics Data System (ADS)

    Schickling, A.

    2009-04-01

    For a better understanding of the complex Soil-Vegetation-Atmosphere exchange processes, long-term monitoring and three dedicated campaigns were conducted in the frame of the collaborative research consortium Transregio TR32. In 2008 integrated measurements in a mainly agricultural dominated region within the Rur catchment (NRW, Germany) covered different vegetation types throughout the vegetation period. This study concentrates on the temporal variations of plant mediated CO2 and H2O exchange processes. The close link between photosynthetic CO2 uptake and transpiration underscores the need to directly determine photosynthetic activity. Seasonal development of the two main crops of the region, winter wheat and sugar beet, has been characterised during five diurnal courses using non invasive methods ranging from leaf to canopy level including gas exchange, PAM fluorometry and eddy correlation measurements. In both species, maximum quantum yield showed no variability independent of date and daytime. But the clear day course of photosynthetic capacity was constant during the day for winter wheat whereas sugar beet showed a constant decrease over the day. The maximum electron transport rate of sugar beet showed significant negative correlation to the non-photochemical quenching while no district pattern in winter wheat. The photosynthetic capacity in both species showed strong correlation to the leaf light reaction efficiency, but became weak when there was less stomatal conductance of leaves. The highest photosynthetic electron transport rates appeared before solar noon for all measurement days. This diurnal development in leaf-level measurements also represented highest CO2 fixation rates before solar noon that were also detected with the eddy covariance method. Our results of leaf and ecosystem level measurements both showed that environmental conditions especially incoming light caused this diurnal development of photosynthetic efficiency determining carbon and

  13. Satellite sampling and the diurnal cycle statistics of Darwin rainfall data

    SciTech Connect

    Soman, V.V.; Valdes, J.B.; North, G.R.

    1995-11-01

    This paper presents an analysis of rainfall data based on the radar echoes collected in the vicinity of Darwin, Australia, during the special observation periods in 1988. The Darwin rainfall data are available in the form of hourly averaged grids of size 141 X 141 with an areal resolution of 2 km X 2 km. The data are available for approximately 19 days in the first subset and for 22 days in the second. Since the rainfall data were taken over both the land and the ocean, separate analyses were performed for land and ocean surfaces; thus, three univariate time series (for land, ocean, and combination) are presented for each set. Time series analysis was performed in both time and frequency domains, and both the correlogram and periodogram showed the presence of a strong diurnal cycle in all the time series. Considerable variations can be seen in the diurnal cycles of these time series. To analyze the effect of the diurnal cycle on the sampling errors, flush visits of idealized satellites were simulated. The root-mean-square (rms) errors were especially large for satellites with sampling intervals of 6 and 12 h (about 20% of the mean for the box size of 280 km X 280 km, for 20 days). The rms errors were very large ({approximately}65%) for a sampling interval of 24 h, which is a possibility for the Defense Military Satellite Program satellites. The sampling errors were only 5%-10% for non-sun-synchronous orbiters. This result should be considered for satellite mission planning purposes. 12 refs., 10 figs., 4 tabs.

  14. Diurnal Variations in Solar Ultraviolet Radiation on Horizontal and Vertical Plane

    PubMed Central

    Hu, LW; Gong, HZ; Jun Yu, D; Gao, Q; Gao, N; Wang, M; Yan, Y; Wang, Y; Yu, Jiaming; Liu, Y

    2010-01-01

    Background: In general, measurements of solar ultraviolet (UV) radiation are related to horizontal surfaces. While the humans walking and standing outdoors expose to the natural solar UV radiation, their eyes, cheeks, extremities, trunks, or many other anatomical sites are close to vertical plane and random orient to different directions. In this study, we characterized the diurnal variations in solar UV on horizontal and vertical plane which may be helpful to obtain more relevant information on UV exposure of humans. Methods: The UV exposure on vertical and horizontal plane were measured using Solar-UV Sensors in Shenyang (41°51″N, 123°27″E) and Sanya (18°19′N, 109°42′E), PR China. Results: As the well known, the diurnal variations in solar UV on horizontal plane in a sunny day exhibited unimodal distributions, reached a single UV peak exposure at around solar noon. However, the diurnal variations on vertical plane presented bimodal distributions, with two peaks in summer in Shenyang and Sanya, and a unimodal distribution in winter in Shenyang. In spring and autumn in Shenyang, the UV exposure around noon were slightly flat with no significant peaks but relative high. When the Solar Elevation Angle (SEA) is about 40°, the vertical plane may potentially receiving maximal unweighted total solar UV radiation exposures. Conclusion: The results potentially showed that the protection of some vertical and near-vertical anatomical sites of human body from high UV exposure should not only focused on the periods of before and after noon especially in high SEA places. PMID:23113025

  15. Evolutionary transformation of rod photoreceptors in the all-cone retina of a diurnal garter snake.

    PubMed

    Schott, Ryan K; Müller, Johannes; Yang, Clement G Y; Bhattacharyya, Nihar; Chan, Natalie; Xu, Mengshu; Morrow, James M; Ghenu, Ana-Hermina; Loew, Ellis R; Tropepe, Vincent; Chang, Belinda S W

    2016-01-12

    Vertebrate retinas are generally composed of rod (dim-light) and cone (bright-light) photoreceptors with distinct morphologies that evolved as adaptations to nocturnal/crepuscular and diurnal light environments. Over 70 years ago, the "transmutation" theory was proposed to explain some of the rare exceptions in which a photoreceptor type is missing, suggesting that photoreceptors could evolutionarily transition between cell types. Although studies have shown support for this theory in nocturnal geckos, the origins of all-cone retinas, such as those found in diurnal colubrid snakes, remain a mystery. Here we investigate the evolutionary fate of the rods in a diurnal garter snake and test two competing hypotheses: (i) that the rods, and their corresponding molecular machinery, were lost or (ii) that the rods were evolutionarily modified to resemble, and function, as cones. Using multiple approaches, we find evidence for a functional and unusually blue-shifted rhodopsin that is expressed in small single "cones." Moreover, these cones express rod transducin and have rod ultrastructural features, providing strong support for the hypothesis that they are not true cones, as previously thought, but rather are modified rods. Several intriguing features of garter snake rhodopsin are suggestive of a more cone-like function. We propose that these cone-like rods may have evolved to regain spectral sensitivity and chromatic discrimination as a result of ancestral losses of middle-wavelength cone opsins in early snake evolution. This study illustrates how sensory evolution can be shaped not only by environmental constraints but also by historical contingency in forming new cell types with convergent functionality.

  16. Nocturnal ranging by a diurnal primate: are ring-tailed lemurs (Lemur catta) cathemeral?

    PubMed

    Parga, Joyce A

    2011-07-01

    Cathemerality, an activity pattern comprised of distinct periods of diurnal and nocturnal activity, is a trait found among several of the Malagasy strepsirhines and one species of Aotus. Because occasional anecdotal reports suggest that some diurnal primates can be active at night, I investigated the possibility of nocturnal ranging behavior in the ring-tailed lemur (Lemur catta) by using global positioning system (GPS) collars programmed to collect data across a 24-h period. Five individuals in a provisioned, free-ranging L. catta colony on St. Catherines Island, Georgia, USA, wore GPS collars across 1 week of the mating season. Results revealed that night ranging behavior occurred between the h of 1900 and 0530. An evaluation of the effect of moonlight on nocturnal activity showed that a greater rate of travel occurred during moonlit periods as opposed to periods when the moon had not yet risen. Distance travelled at night decreased across the deployment period, likely because of a decrease in available moonlight over time, as the lemurs were collared during a waning moon. Fewer mating opportunities over time may have also been responsible for the decrease in night ranging, because the number of females in estrus declined across the deployment period. Future research is needed to separate the effects of moonlight and mating activity on night ranging in this species, as well as to evaluate whether L. catta in Madagascar show night ranging similar to L. catta on SCI. These data raise the possibility that L. catta may be cathemeral, with an activity pattern fluctuating between diurnality and cathemerality in accordance with shifts in environmental conditions.

  17. Patterns in diurnal airspace use by migratory landbirds along an ecological barrier

    USGS Publications Warehouse

    Peterson, Anna C.; Niemi, Gerald J.; Johnson, Douglas H.

    2015-01-01

    Migratory bird populations and survival are affected by conditions experienced during migration. While many studies and conservation and management efforts focus on terrestrial stoppage and staging areas, the aerial environment through which migrants move also is subjected to anthropogenic impacts with potential consequences to migratory movement and survival. During autumn migration, the northern coastline of Lake Superior acts as an ecological barrier for many landbirds migrating out of the boreal forests of North America. From 24 observation points, we assessed the diurnal movements of birds throughout autumn migration, 2008-2010, within a 210 km by 10 km coastal region along the northern coast of Lake Superior. Several raptor species showed patterns in airspace associated with topographic features such as proximity to the coastline and presence of ridgelines. Funneling movement, commonly used to describe the concentration of raptors along a migratory diversion line that either prevents or enhances migration progress, occurred only for Bald and Golden Eagles. This suggests a "leaky" migration funnel for most migratory raptors (e.g., migrating birds exiting the purported migration corridor). Passerines migrating during the late season showed more spatial and temporal structure in airspace distribution than raptors, including funneling and an association with airspace near the coast. We conclude that a) the diurnal use of airspace by many migratory landbirds is patterned in space and time, b) autumn count sites situated along ecological barriers substantially underestimate the number of raptors due to 'leakage' out of these concentration areas, and c) the magnitude and structure of diurnal passerine movements in airspace have been overlooked. The heavy and structured use of airspace by migratory landbirds, especially the airspace associated with anthropogenic development (e.g., buildings, towers, turbines) necessitates a shift in focus to airspace management and

  18. Unique Regulation of the Melatonin Synthetic Pathway in the Retina of Diurnal Female Arvicanthis ansorgei (Rodentia).

    PubMed

    Gianesini, Coralie; Clesse, Daniel; Tosini, Gianluca; Hicks, David; Laurent, Virginie

    2015-09-01

    Knowledge about melatonin synthesis and its potential roles within the retina remains fragmented, especially in mammals where studies have focused on the penultimate enzyme of melatonin synthesis arylalkylamine N-acetyltransferase (AA-NAT), whereas the final enzyme necessary for melatonin production is hydroxyindole-O-methytransferase (HIOMT). We explored multiple parameters of the melatonin synthetic pathway in the cone-rich retina of a diurnal rodent, Arvicanthis ansorgei, cones being previously implicated as probable reservoirs of melatonin production. We analyzed the temporal and spatial expression of Aa-nat mRNA and AA-NAT protein and enzymatic activity of AA-NAT, HIOMT, as well as the melatonin receptor type 1 and melatonin itself. We report that Aa-nat mRNA was localized principally to cones and ganglion cells (retinal ganglion cell [RGC]) with opposing cyclic expression, being maximal in cones during the night, and maximal in RGC in the daytime. AA-NAT protein was also immunolocalized to these same populations, and was present and active throughout the 24-hour period. HIOMT immunolocalization mirrored that of AA-NAT, but expression levels and activity were extremely low and remained uniform throughout the 24-hour period. MT1 showed a complementary expression pattern to the synthetic enzymes, present in rod photoreceptors, some inner retinal neurons and RGC. Surprisingly, melatonin levels were consistently low throughout the day/night cycle, in accordance with the low activity levels of HIOMT. These data demonstrate that the melatonin synthetic pathway in a diurnal rodent differs from that described for other tissues and species (nocturnal and diurnal), the contrasting phase expression in photoreceptors and RGC, suggesting distinct roles in these populations.

  19. The influence of diurnal winds on phytoplankton dynamics in a coastal upwelling system off southwestern Africa

    NASA Astrophysics Data System (ADS)

    Lucas, Andrew J.; Pitcher, Grant C.; Probyn, Trevor A.; Kudela, Raphael M.

    2014-03-01

    At a coastal upwelling zone near 30°S latitude, diurnal wind variability forced energetic inertial current oscillations (>0.5 m s-1) that materially influenced phytoplankton distribution and productivity. The diurnal-inertial band resonance found at this latitude in the Benguela upwelling system allowed rapid, efficient transfer of energy from counterclockwise rotating winds into anticyclonic currents upon the onset of the transition from relaxation to upwelling conditions. These inertial band oscillations caused regular pycnocline outcropping at the surface and the vertical advection of nutrient-rich waters in the coastal zone. Vertical pycnocline outcropping was coincident with the vertical redistribution of chlorophyll a fluorescence from a subsurface maximum to entrainment into the surface mixed layer, in effect turning vertical phytoplankton gradients into horizontal ones. The shear caused by the vertical structure of the inertial oscillations during (and after) the onset of wind forcing was intense enough to erode the strong stratification established during a prior relaxation period, according to Richardson number and strain analyses. This diapycnal mixing also had the consequence of mixing heat and chlorophyll downwards and nutrient-rich water upwards, such that the surface nitrate concentration became non-zero. Chlorophyll concentrations thereafter increased in what qualitatively appeared to be a phytoplankton bloom. This diurnal-inertial resonance-driven mechanism for mixing-driven nutrient flux, embedded within the low-frequency advective vertical flux forced by Ekman dynamics, enhanced the efficiency of wind forcing to produce high phytoplankton productivity, and is likely to be of first-order importance in bloom dynamics in the study area (including harmful algal blooms). Our results argue that, in general, high-frequency physical dynamics should be considered when studying the bottom-up forcing of algal blooms and red tide events.

  20. Wake flow variability in a wind farm throughout the diurnal cycle

    NASA Astrophysics Data System (ADS)

    Abkar, Mahdi; Sharifi, Ahmad; Porté-Agel, Fernando

    2015-04-01

    The atmospheric boundary layer (ABL) undergoes substantial changes in its structure and dynamics in the course of a day due to the transient nature of forcing factors such as the surface fluxes of heat and momentum. The non-stationary nature of the mean wind and turbulence in the ABL, associated with the diurnal cycle, can in turn affect the structure of wind turbine wakes and their effects on power losses within wind farms. In this research, large-eddy simulation (LES) is used to study the evolution of the turbine wakes and their effects on power losses inside an idealized finite-size wind farm in the course of two full diurnal cycles. In the LES, turbulent subgrid-scale stresses are modeled using tuning-free Lagrangian scale-dependent dynamic models, while the turbine-induced forces are parameterized using a dynamic actuator disk model with rotation. To minimize the effects of the initial conditions on the results, our analysis is focused on the second diurnal cycle. The simulation results show a strong effect of atmospheric stability on the wind farm wakes and associated power losses. During the night, the relatively low turbulence intensity of the ambient ABL flow results in a relatively slow rate of entrainment of momentum into the wake and, consequently, a slow wake recovery. In contrast, during the day the positive buoyancy flux and associated turbulence production lead to a relatively high turbulence level in the background ABL flow, which enhances turbulent mixing and wake recovery. As a result, the averaged power deficit in the wind farm is found to increase with increasing thermal stability. In particular for that day, the averaged power deficit increased from 28% under the most convective condition to about 66% under the most stable condition.

  1. Global transcriptomic analysis of Cyanothece 51142 reveals robust diurnal oscillation of central metabolic processes

    SciTech Connect

    Stockel, Jana; Welsh, Eric A.; Liberton, Michelle L.; Kunnavakkam, Rangesh V.; Aurora, Rajeev; Pakrasi, Himadri B.

    2008-04-22

    Cyanobacteria are oxygenic photosynthetic organisms, and the only prokaryotes known to have a circadian cycle. Unicellular diazotrophic cyanobacteria such as Cyanothece 51142 can fix atmospheric nitrogen, a process exquisitely sensitive to oxygen. Thus, the intracellular environment of Cyanothece oscillates between aerobic and anaerobic conditions during a day-night cycle. This is accomplished by temporal separation of two processes: photosynthesis during the day, and nitrogen fixation at night. While previous studies have examined periodic changes transcript levels for a limited number of genes in Cyanothece and other unicellular diazotrophic cyanobacteria, a comprehensive study of transcriptional activity in a nitrogen-fixing cyanobacterium is necessary to understand the impact of the temporal separation of photosynthesis and nitrogen fixation on global gene regulation and cellular metabolism. We have examined the expression patterns of nearly 5000 genes in Cyanothece 51142 during two consecutive diurnal periods. We found that ~30% of these genes exhibited robust oscillating expression profiles. Interestingly, this set included genes for almost all central metabolic processes in Cyanothece. A transcriptional network of all genes with significantly oscillating transcript levels revealed that the majority of genes in numerous individual pathways, such as glycolysis, pentose phosphate pathway and glycogen metabolism, were co-regulated and maximally expressed at distinct phases during the diurnal cycle. Our analyses suggest that the demands of nitrogen fixation greatly influence major metabolic activities inside Cyanothece cells and thus drive various cellular activities. These studies provide a comprehensive picture of how a physiologically relevant diurnal light-dark cycle influences the metabolism in a photosynthetic bacterium

  2. Characterizing Diurnal and Seasonal Cycles in Monsoon Systems from TRMM and CEOP Observations

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.

    2007-01-01

    The CEOP Inter-Monsoon Study (CIMS) is one of the two main science drivers of CEOP that aims to (a) provide better understanding of fundamental physical processes in monsoon regions around the world, and (b) demonstrate the synergy and utility of CEOP data in providing a pathway for model physics evaluation and improvement. As the data collection phase for EOP-3 and EOP-4 is being completed, two full annual cycles (2003-2004) of research-quality data sets from satellites, reference sites, and model output location time series (MOLTS) have been processed and made available for data analyses and model validation studies. This article presents preliminary results of a CIMS study aimed at the characterization and intercomparison of all major monsoon systems. The CEOP reference site data proved its value in such exercises by being a powerful tool to cross-validate the TRMM data, and to intercompare with multi-model results in ongoing work. We use 6 years (1998-2003) of pentad CEOP/TRMM data with 2 deg x 2.5 deg. latitude-longitude grid, over the domain of interests to define the monsoon climatological diurnal and annual cycles for the East Asian Monsoon (EAM), the South Asian Monsoon (SAM), the West Africa Monsoon (WAM), the North America/Mexican Monsoon (NAM), the South American Summer Monsoon (SASM) and the Australian Monsoon (AUM). As noted, the TRMM data used in the study were cross-validated using CEOP reference site data, where applicable. Results show that the observed diurnal cycle of rain peaked around late afternoon over monsoon land, and early morning over the oceans. The diurnal cycles in models tend to peak 2-3 hours earlier than observed. The seasonal cycles of the EAM and SAM show the strongest continentality, i.e, strong control by continental processes away from the ITCZ. The WAM, and the AUM shows the less continentality, i.e, strong control by the oceanic ITCZ.

  3. Characterizing diurnal and seasonal cycles in monsoon systems from TRMM and CEOP observations

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.

    2006-01-01

    The CEOP Inter-Monsoon Study (CIMS) is one of the two main science drivers of CEOP that aims to (a) provide better understanding of fundamental physical processes in monsoon regions around the world, and (b) demonstrate the synergy and utility of CEOP data in providing a pathway for model physics evaluation and improvement. As the data collection phase for EOP-3 and EOP-4 is being completed, two full annual cycles (2003-2004) of research-quality data sets from satellites, reference sites, and model output location time series (MOLTS) have been processed and made available for data analyses and model validation studies. This article presents preliminary results of a CIMS study aimed at the characterization and intercomparison of all major monsoon systems. The CEOP reference site data proved its value in such exercises by being a powerful tool to cross-validate the TRMM data, and to intercompare with multi-model results in ongoing work. We use 6 years (1998-2003) of pentad CEOP/TRMM data with 2deg x 2.5deg latitude-longitude grid, over the domain of interests to define the monsoon climatological diurnal and annual cycles for the East Asian Monsoon (EAM), the South Asian Monsoon (SAM), the West Africa Monsoon (WAM), the North America/Mexican Monsoon (NAM), the South American Summer Monsoon (SASM) and the Australian Monsoon (AUM). As noted, the TRMM data used in the study were cross-validated using CEOP reference site data, where applicable. Results show that the observed diurnal cycle of rain peaked around late afternoon over monsoon land, and early morning over the oceans. The diurnal cycles in models tend to peak 2-3 hours earlier than observed. The seasonal cycles of the EAM and SAM show the strongest continentality, i.e, strong control by continental processes away from the ITCZ. The WAM, and the AUM shows the less continentality, i.e, strong control by the oceanic ITCZ.

  4. [Effects of fertilization level on diurnal variation of gas exchange of young Eucalyptus grandis leaf].

    PubMed

    Li, Xiao-ping; Wang, Jing-yan; Wang, Dong; Hu, Ting-xing; Chen, Hong-zhi; Gong, Wei

    2010-11-01

    Different levels (0, 90, 180, and 270 g per tree) of compound fertilizer containing 15% N, 15% P2O5, and 15% K2O were applied to young Eucalyptus grandis to study the diurnal variations of its leaf stomatal conductance (Gs), intercellular CO2 concentration (Ci), net photosynthesis rate (Pn), transpiration rate (Tr), water use efficiency (WUE), and vapor pressure deficit on leaf surface (Vpdl) as well as the variation of leaf chlorophyll content, aimed to approach the relationships of E. grandis photosynthesis with fertilization and environmental factors. In all treatments, the diurnal variation of Pn presented a single-peak curve, with the peak at 14:00 and not showing midday depression. The Gs, Tr, and Vpdl showed the similar trend with Pn, while the Ci had a minimum value at 14:00. The WUE demonstrated a double-peak curve, with the first and second peak occurred at 10:00 and 14:00, respectively. Comparing with the control, the mean values of Gs, Pn, Tr, WUE, and chlorophyll a, chlorophyll b, and total chlorophyll contents under fertilization increased by 4.6%-15.9%, 7.8%-21.8%, 4.8%-11.6%, 3.2%-8.8%, 15.5%-62.0%, 14.5%-44.5% and 15.3%-57.1%, respectively, and the increment increased with fertilization level. By contrast, the mean values of Ci and VPdl decreased by 14.5%-44.5% and 15.3%-57.1%, respectively, and the decrement increased with fertilization level. The Gs, Pn, and Tr were significantly correlated with air temperature, relative humidity (RH), and photosynthetic active radiation (PAR), and also, the Gs was significantly correlated with Pn and Tr. It was suggested that fertilization could promote E. grandis growth and enhance its WUE and biological carbon sequestration, and air temperature, RH, PAR, and Gs were the main factors causing the diurnal variations of photosynthesis and transpiration of E. grandis.

  5. Covariability in the Monthly Mean Convective and Radiative Diurnal Cycles in the Amazon

    NASA Technical Reports Server (NTRS)

    Dodson, Jason B.; Taylor, Patrick C.

    2015-01-01

    The diurnal cycle of convective clouds greatly influences the radiative energy balance in convectively active regions of Earth, through both direct presence, and the production of anvil and stratiform clouds. Previous studies show that the frequency and properties of convective clouds can vary on monthly timescales as a result of variability in the monthly mean atmospheric state. Furthermore, the radiative budget in convectively active regions also varies by up to 7 Wm-2 in convectively active regions. These facts suggest that convective clouds connect atmospheric state variability and radiation variability beyond clear sky effects alone. Previous research has identified monthly covariability between the diurnal cycle of CERES-observed top-of-atmosphere radiative fluxes and multiple atmospheric state variables from reanalysis over the Amazon region. ASVs that enhance (reduce) deep convection, such as CAPE (LTS), tend to shift the daily OLR and cloud albedo maxima earlier (later) in the day by 2-3 hr. We first test the analysis method using multiple reanalysis products for both the dry and wet seasons to further investigate the robustness of the preliminary results. We then use CloudSat data as an independent cloud observing system to further evaluate the relationships of cloud properties to variability in radiation and atmospheric states. While CERES can decompose OLR variability into clear sky and cloud effects, it cannot determine what variability in cloud properties lead to variability in the radiative cloud effects. Cloud frequency, cloud top height, and cloud microphysics all contribute to the cloud radiative effect, all of which are observable by CloudSat. In addition, CloudSat can also observe the presence and variability of deep convective cores responsible for the production of anvil clouds. We use these capabilities to determine the covariability of convective cloud properties and the radiative diurnal cycle.

  6. Diurnal variation in hepatic expression of the rat S14 gene is synchronized by the photoperiod

    SciTech Connect

    Kinlaw, W.B.; Fish, L.H.; Schwartz, H.L.; Oppenheimer, J.H.

    1987-04-01

    We have analyzed the factors responsible for the circadian variation in rat hepatic mRNA-S14. Regulation of this sequence, which is found in lipogenic tissues and encodes a protein (S14) believed to be associated with fatty acid synthesis, is an excellent model of the interaction of thyroid hormone and dietary factors at the hepatocellular level. The mRNA exhibits a 3-fold diurnal variation (peak, approximately 2000 h; nadir, 0800 h) in ad libitum feeding rats on a 12-h light, 12-h dark photoschedule. We studied the effects of the photoschedule, periodic food intake, hypophysectomy, and induction by thyroid hormone (T3) on the mRNA-S14 rhythm. Adaptation to feeding restricted to either light or dark periods for 15 days did not greatly affect the diurnal rhythm. Photoreversal resulted in a 180 degrees phase shift, whereas the rhythm persisted in the presence of constant light. Oscillation continued around a higher baseline after a receptor-saturating dose of T3 in both normal and hypophysectomized rats. Our results indicate primary entrainment of the mRNA-S14 diurnal rhythm to the photoperiod, rather than to periodic food intake. Moreover, the circadian regulatory signal, which probably originates in the central nervous system, appears capable of antagonizing a maximal T3-inductive stimulus and does not originate in the pituitary gland. Persistence of the oscillation in constant light rules out circulating melatonin as the mediator. Synchronization of the rhythm by the photoschedule suggests that neuroendocrine factors are important determinants of rhythmic changes in hepatic gene expression.

  7. Diurnal variations in luminal and stromal areas of choroid in normal eyes

    PubMed Central

    Kinoshita, Takamasa; Mitamura, Yoshinori; Shinomiya, Kayo; Egawa, Mariko; Iwata, Akiko; Fujihara, Akiko; Ogushi, Yoko; Semba, Kentaro; Akaiwa, Kei; Uchino, Eisuke; Sonoda, Shozo; Sakamoto, Taiji

    2017-01-01

    Aims To determine the diurnal variations of the luminal and stromal areas of the choroid in normal eyes. Methods This was a prospective observational study of 38 eyes of 38 normal subjects. The blood pressure, heart rate, intraocular pressure and enhanced depth imaging optical coherence tomographic (EDI-OCT) images were recorded every 3 hours between 6:00 and 21:00 hours. The horizontal EDI-OCT images of the subfoveal choroid were converted to binary images. The central choroidal thickness (CCT), total cross-sectional choroidal area, the luminal areas, stromal areas and the ratio of luminal area to total choroidal area (L/C ratio) were determined. Results There were significant diurnal variations in the CCT, total choroidal area, luminal area and L/C ratio with the maximum values at 6:00 hours and the minimum values at 15:00 hours (p<0.001 for the CCT, p=0.011 for the total choroidal area, p<0.001 for the luminal area and p=0.014 for the L/C ratio). There was no significant variation in the stromal area (p=0.216). The range of fluctuation in the CCT was significantly correlated with that in the luminal area and the total choroidal area (p<0.001). However, there was no significant correlation between the fluctuation range in the CCT and that in the stromal area (p=0.095). There was no statistical relationship between the systemic parameters and the choroidal parameters. Conclusions The changes in the luminal area are most likely responsible for the diurnal change in the CCT and subfoveal choroidal area. Trial registration number UMIN000019060, Pre-results. PMID:27297216

  8. Diurnal temperature effect on nitrate removal and production efficiency in bedform-induced hyporheic zones

    NASA Astrophysics Data System (ADS)

    Zheng, L.; Cardenas, M. B.

    2014-12-01

    Rivers and aquifers are connected through the hyporheic zone (HZ). Pore water in the subsurface sediments is continuously exchanged with the overlying surface water. The exchange of water, mass and energy occurring along the surface-subsurface interface or within the HZ exerts a strong influence on the quality of both surface and subsurface waters, and fluvial ecology. Moreover, the HZ is rich in biologically active sediment, creating a favorable condition for microbially-facilitated reactions to occur, including organic carbon oxidation (aerobic respiration), nitrification, and denitrification. Inorganic N, especially NO3-, is of concern as a drinking water pollutant and as a cause for eutrophication that threatens ecosystems. The biogeochemical reactions in the HZ could produce or consume NO3- and thus the HZ could serve a nitrate source or sink role in the fluvial system. In addition, hyporheic exchange across the sediment-water interface (SWI) leads to penetration of diel temperature cycles from the river, leading to dynamic HZ temperature pattern. This in turn affects biogeochemical reactions in the HZ. The main objective of this study is to integrate all the processes that occur along the SWI to understand how diurnal temperature variations affect the biogeochemical function of the HZ. We conducted numerical simulations of coupled turbulent open-channel fluid flow, porous fluid flow, porous heat transport and reactive solute transport to study feedbacks and coupling between these processes. We assumed sinusoidally varying diurnal temperature variations. We studied the effects of different mean temperatures and different amplitudes of the diurnal temperature variations on nitrate removal or production efficiency in the HZ. The simulation results show that the average temperature effect on the HZ nitrate source-sink functionality and its associated efficiency has strong dependence on the [NO3-]/[NH4+ ] ratio in the river. However, the effects of the

  9. Seasonal and diurnal variations of aerosol extinction profile and type distribution from CALIPSO 5-year observations

    NASA Astrophysics Data System (ADS)

    Huang, Lei; Jiang, Jonathan H.; Tackett, Jason L.; Su, Hui; Fu, Rong

    2013-05-01

    The new Level 3 aerosol profile data derived from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) provide a multiyear global aerosol distribution with high vertical resolution. We analyzed seasonal and diurnal variations of the vertical distributions of aerosol properties represented by 5-year CALIPSO data. Results show that dust, smoke, and polluted dust are the most frequently detected aerosol types during all seasons. Dust is the dominant type, especially in the middle to upper troposphere, over most areas during boreal spring and summer, while smoke and polluted dust tend to dominate during biomass burning seasons. The seasonal variations of dust layer top height and dust contribution to all-aerosol extinction are positively correlated with the seasonal variation of the dust occurrence frequency. The seasonal cycle of aerosol properties over west Australia is similar to that over biomass burning regime areas, despite its desert regime. In general, smoke is detected more frequently from the lower to middle troposphere; clean marine and polluted continental aerosols are detected more frequently, while polluted dust is detected less frequently, in the lower troposphere during nighttime than daytime. The all-aerosol extinction is generally larger, and the aerosol layer top is detected at high altitudes more frequently during nighttime than daytime. The diurnal changes of aerosol properties are similar within the same aerosol regime. Dust extinction shows little diurnal variation except when dust is the dominant aerosol type. The results contribute to an initial global 3-D aerosol climatology which will likely be extended and improved in the future.

  10. Concurrent and longitudinal associations of basal and diurnal cortisol with mental health symptoms in early adolescence.

    PubMed

    Shirtcliff, Elizabeth A; Essex, Marilyn J

    2008-11-01

    Recent biosocial theories postulate that both biological risk and the social context influence the development of mental health problems [Boyce and Ellis (2005) Development and Psychopathology, 17(2), 271-301]. Guided by this framework, we examined whether basal cortisol and its diurnal rhythm were associated with mental health symptoms in early adolescence. Because cross-sectional and longitudinal investigations sometimes reveal different cortisol-mental health associations, we examined the association both concurrently and longitudinally when children transition to middle school, a time which entails a major change in social context from single to multiple teachers, classrooms, and sets of classmates. Salivary cortisol was measured three times a day (waking, afternoon, and bedtime) across 3 days when adolescents were 5th graders. Mental health was measured when adolescents were in 5th and 7th grades, just before and after the transition to middle school. To deal with the substantial comorbidity of internalizing and externalizing symptoms at this developmental stage, mental health measures distinguished overall symptom severity from the preponderance of internalizing versus externalizing symptoms (i.e., directionality). A three-level Hierarchical Linear Model was used to extract basal cortisol and its diurnal rhythm separate from the day-to-day and within-the-day fluctuations in cortisol in response to daily experiences. Results were specific to symptom severity, suggesting that cortisol is a nonspecific risk factor for mental health symptoms in young adolescents. At 5th grade, low basal cortisol was associated with concurrent symptom severity. However, longitudinally, it was adolescents with high cortisol at 5th grade who were at risk for increasing mental health symptoms by 7th grade. Flat diurnal rhythms in 5th grade were related to levels of symptom severity at both 5th and 7th grades. Considering the change in social context, as defined by the transition to

  11. Evolutionary transformation of rod photoreceptors in the all-cone retina of a diurnal garter snake

    PubMed Central

    Schott, Ryan K.; Müller, Johannes; Yang, Clement G. Y.; Bhattacharyya, Nihar; Chan, Natalie; Xu, Mengshu; Morrow, James M.; Ghenu, Ana-Hermina; Loew, Ellis R.; Tropepe, Vincent; Chang, Belinda S. W.

    2016-01-01

    Vertebrate retinas are generally composed of rod (dim-light) and cone (bright-light) photoreceptors with distinct morphologies that evolved as adaptations to nocturnal/crepuscular and diurnal light environments. Over 70 years ago, the “transmutation” theory was proposed to explain some of the rare exceptions in which a photoreceptor type is missing, suggesting that photoreceptors could evolutionarily transition between cell types. Although studies have shown support for this theory in nocturnal geckos, the origins of all-cone retinas, such as those found in diurnal colubrid snakes, remain a mystery. Here we investigate the evolutionary fate of the rods in a diurnal garter snake and test two competing hypotheses: (i) that the rods, and their corresponding molecular machinery, were lost or (ii) that the rods were evolutionarily modified to resemble, and function, as cones. Using multiple approaches, we find evidence for a functional and unusually blue-shifted rhodopsin that is expressed in small single “cones.” Moreover, these cones express rod transducin and have rod ultrastructural features, providing strong support for the hypothesis that they are not true cones, as previously thought, but rather are modified rods. Several intriguing features of garter snake rhodopsin are suggestive of a more cone-like function. We propose that these cone-like rods may have evolved to regain spectral sensitivity and chromatic discrimination as a result of ancestral losses of middle-wavelength cone opsins in early snake evolution. This study illustrates how sensory evolution can be shaped not only by environmental constraints but also by historical contingency in forming new cell types with convergent functionality. PMID:26715746

  12. North American monsoon precipitation and its precursors: Processes at the seasonal and diurnal scale

    NASA Astrophysics Data System (ADS)

    Gaynor, Nicole June Schiffer

    The Weather Research and Forecasting (WRF) model was run at 100 km, 25 km, and 10 km resolution for the 2000 and 2004 monsoon seasons (July-September), a dry year and a wet year. These years were chosen to represent contrasting precipitation outcomes to assure that results were robust across different monsoon conditions. Model precipitation was compared to precipitation from the Modern-Era Retrospective Reanalysis (MERRA), the North American Regional Reanalysis (NARR), and Tropical Rainfall Measuring Mission (TRMM). Then WRF, MERRA, and NARR were used to investigate the relationships between precipitation and the other moisture budget variables, the large-scale flow, and atmospheric stability on the seasonal and diurnal scales. On both the seasonal and diurnal scale, flow was key to the location and intensity of precipitation. In 2004, the subtropical high over the south-central United States was about 300 km west of its location in 2000 at 700 hPa. The shift was also evident in vertically-integrated moisture flux, which then changed the pattern and intensity of moisture flux convergence (MFC), convective available potential energy (CAPE) and convective inhibition (CIN), and precipitation over Mexico and the Gulf of California. Over Arizona and New Mexico, transient disturbances, like tropical waves, were more important than the diurnal cycle to precipitation. Despite similar spatial distributions of precipitation, WRF, NARR, MERRA, and TRMM showed very different frequencies of light and heavy rain. Such uncertainty in the character of rainfall can impact a variety of stakeholders and decision makers across the NAM region. The WRF model tended to produce heavier precipitation across the NAM region compared to MERRA, NARR, and TRMM as a result of stronger MFC and higher CAPE, especially over the Gulf of California. Beyond the resolution needed to adequately reproduce the Baja California and Gulf of California, higher model resolution tended to increase and localize

  13. Individual-based ant-plant networks: diurnal-nocturnal structure and species-area relationship.

    PubMed

    Dáttilo, Wesley; Fagundes, Roberth; Gurka, Carlos A Q; Silva, Mara S A; Vieira, Marisa C L; Izzo, Thiago J; Díaz-Castelazo, Cecília; Del-Claro, Kleber; Rico-Gray, Victor

    2014-01-01

    Despite the importance and increasing knowledge of ecological networks, sampling effort and intrapopulation variation has been widely overlooked. Using continuous daily sampling of ants visiting three plant species in the Brazilian Neotropical savanna, we evaluated for the first time the topological structure over 24 h and species-area relationships (based on the number of extrafloral nectaries available) in individual-based ant-plant networks. We observed that diurnal and nocturnal ant-plant networks exhibited the same pattern of interactions: a nested and non-modular pattern and an average level of network specialization. Despite the high similarity in the ants' composition between the two collection periods, ant species found in the central core of highly interacting species totally changed between diurnal and nocturnal sampling for all plant species. In other words, this "night-turnover" suggests that the ecological dynamics of these ant-plant interactions can be temporally partitioned (day and night) at a small spatial scale. Thus, it is possible that in some cases processes shaping mutualistic networks formed by protective ants and plants may be underestimated by diurnal sampling alone. Moreover, we did not observe any effect of the number of extrafloral nectaries on ant richness and their foraging on such plants in any of the studied ant-plant networks. We hypothesize that competitively superior ants could monopolize individual plants and allow the coexistence of only a few other ant species, however, other alternative hypotheses are also discussed. Thus, sampling period and species-area relationship produces basic information that increases our confidence in how individual-based ant-plant networks are structured, and the need to consider nocturnal records in ant-plant network sampling design so as to decrease inappropriate inferences.

  14. The Diurnal Variation on Cardiovascular Endurance Performance of Secondary School Athlete Student

    PubMed Central

    Chin, Chun-Yip; Chow, Gary Chi-Ching; Hung, Kwong-Chung; Kam, Lik-Hang; Chan, Ka-Chun; Mok, Yuen-Ting; Cheng, Nga-Mei

    2015-01-01

    Background: The previous investigations in diurnal variation of endurance sports performance did not reach a consensus and have been limited. This study would be a valuable resource for endurance sports trainers and event managers to plan their training and competition in a specific time of day. Objectives: The aim of this study is to find out the diurnal variation in cardiovascular endurance performance in the young athletes. Materials and Methods: Thirty five athlete students (15.17 ± 1.62 years) participated in this study. Maximal oxygen uptake (VO2max), post-exercise percentage of maximal heart rate (MHR% post-ex), post-exercise body temperature (BTemppost-ex), and post exercise blood lactic acid level (LApost-ex) were measured in this study. Three non-consecutive testings: A) Morning (09:00-10:00; AM), B) Noon (12:00-13:00; NN) and C) Afternoon (16:00-17:00; PM) were conducted. Participants were required to follow the meal plan and resting schedule for all testing days. Results: VO2max was significantly higher at NN (F2. 68 = 3.29, P < 0.05, η2 = 0.088) in comparison with PM. The MHR%post-ex, BTemppost-ex, LApost-ex was not significantly different among three times of day. Conclusions: Diurnal effect on endurance performance was found and the highest exercise VO2max was identified at noon. Secondary school students or young athletes are recommended to have sports training related to VO2max at noon for the purpose of maximizing training effectiveness. PMID:26448833

  15. Diurnal adjustment in ultraviolet sunscreen protection is widespread among higher plants.

    PubMed

    Barnes, Paul W; Flint, Stephan D; Tobler, Mark A; Ryel, Ronald J

    2016-05-01

    The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) in the epidermis of higher plants reduces the penetration of solar UV radiation to underlying tissues and is a primary mechanism of acclimation to changing UV conditions resulting from ozone depletion and climate change. Previously we reported that several herbaceous plant species were capable of rapid, diurnal adjustments in epidermal UV transmittance (T UV), but how widespread this phenomenon is among plants has been unknown. In the present study, we tested the generality of this response by screening 37 species of various cultivated and wild plants growing in four locations spanning a gradient of ambient solar UV and climate (Hawaii, Utah, Idaho and Louisiana). Non-destructive measurements of adaxial T UV indicated that statistically significant midday decreases in T UV occurred in 49 % of the species tested, including both herbaceous and woody growth forms, and there was substantial interspecific variation in the magnitude of these changes. In general, plants in Louisiana exhibited larger diurnal changes in T UV than those in the other locations. Moreover, across all taxa, the magnitude of these changes was positively correlated with minimum daily air temperatures but not daily UV irradiances. Results indicate that diurnal changes in UV shielding are widespread among higher plants, vary both within and among species and tend to be greatest in herbaceous plants growing in warm environments. These findings suggest that plant species differ in their UV protection "strategies" though the functional and ecological significance of this variation in UV sunscreen protection remains unclear at present.

  16. Monitoring seasonal and diurnal changes in photosynthetic pigments with automated PRI and NDVI sensors

    NASA Astrophysics Data System (ADS)

    Gamon, J. A.; Kovalchuck, O.; Wong, C. Y. S.; Harris, A.; Garrity, S. R.

    2015-07-01

    The vegetation indices normalized difference vegetation index (NDVI) and photochemical reflectance index (PRI) provide indicators of pigmentation and photosynthetic activity that can be used to model photosynthesis from remote sensing with the light-use-efficiency model. To help develop and validate this approach, reliable proximal NDVI and PRI sensors have been needed. We tested new NDVI and PRI sensors, "spectral reflectance sensors" (SRS sensors; recently developed by Decagon Devices, during spring activation of photosynthetic activity in evergreen and deciduous stands. We also evaluated two methods of sensor cross-calibration - one that considered sky conditions (cloud cover) at midday only, and another that also considered diurnal sun angle effects. Cross-calibration clearly affected sensor agreement with independent measurements, with the best method dependent upon the study aim and time frame (seasonal vs. diurnal). The seasonal patterns of NDVI and PRI differed for evergreen and deciduous species, demonstrating the complementary nature of these two indices. Over the spring season, PRI was most strongly influenced by changing chlorophyll : carotenoid pool sizes, while over the diurnal timescale, PRI was most affected by the xanthophyll cycle epoxidation state. This finding demonstrates that the SRS PRI sensors can resolve different processes affecting PRI over different timescales. The advent of small, inexpensive, automated PRI and NDVI sensors offers new ways to explore environmental and physiological constraints on photosynthesis, and may be particularly well suited for use at flux tower sites. Wider application of automated sensors could lead to improved integration of flux and remote sensing approaches for studying photosynthetic carbon uptake, and could help define the concept of contrasting vegetation optical types.

  17. Monitoring seasonal and diurnal changes in photosynthetic pigments with automated PRI and NDVI sensors

    NASA Astrophysics Data System (ADS)

    Gamon, J. A.; Kovalchuk, O.; Wong, C. Y. S.; Harris, A.; Garrity, S. R.

    2015-02-01

    The vegetation indices normalized difference vegetation index (NDVI) and photochemical reflectance index (PRI) provide indicators of pigmentation and photosynthetic activity that can be used to model photosynthesis from remote sensing with the light-use efficiency model. To help develop and validate this approach, reliable proximal NDVI and PRI sensors have been needed. We tested new NDVI and PRI sensors, "SRS" sensors recently developed by Decagon Devices, during spring activation of photosynthetic activity in evergreen and deciduous stands. We also evaluated two methods of sensor cross-calibration, one that considered sky conditions (cloud cover) at midday only, and the other that also considered diurnal sun angle effects. Cross-calibration clearly affected sensor agreement with independent measurements, with the best method dependent upon the study aim and time frame (seasonal vs. diurnal). The seasonal patterns of NDVI and PRI differed for evergreen and deciduous species, demonstrating the complementary nature of these two indices. Over the spring season, PRI was most strongly influenced by changing chlorophyll : carotenoid pool sizes, while over the diurnal time scale PRI was most affected by the xanthophyll cycle epoxidation state. This finding demonstrates that the SRS PRI sensors can resolve different processes affecting PRI over different time scales. The advent of small, inexpensive, automated PRI and NDVI sensors offers new ways to explore environmental and physiological constraints on photosynthesis, and may be particularly well-suited for use at flux tower sites. Wider application of automated sensors could lead to improved integration of flux and remote sensing approaches to studying photosynthetic carbon uptake, and could help define the concept of contrasting vegetation optical types.

  18. Physiological, Diurnal and Stress-Related Variability of Cadmium-Metallothionein Gene Expression in Land Snails.

    PubMed

    Pedrini-Martha, Veronika; Niederwanger, Michael; Kopp, Renate; Schnegg, Raimund; Dallinger, Reinhard

    2016-01-01

    The terrestrial Roman snail Helix pomatia has successfully adapted to strongly fluctuating conditions in its natural soil habitat. Part of the snail's stress defense strategy is its ability to express Metallothioneins (MTs). These are multifunctional, cysteine-rich proteins that bind and inactivate transition metal ions (Cd(2+), Zn(2+), Cu(+)) with high affinity. In Helix pomatia a Cadmium (Cd)-selective, inducible Metallothionein Isoform (CdMT) is mainly involved in detoxification of this harmful metal. In addition, the snail CdMT has been shown to also respond to certain physiological stressors. The aim of the present study was to investigate the physiological and diurnal variability of CdMT gene expression in snails exposed to Cd and non-metallic stressors such as desiccation and oxygen depletion. CdMT gene expression was upregulated by Cd exposure and desiccation, whereas no significant impact on the expression of CdMT was measured due to oxygen depletion. Overall, Cd was clearly more effective as an inducer of the CdMT gene expression compared to the applied non-metallic stressors. In unexposed snails, diurnal rhythmicity of CdMT gene expression was observed with higher mRNA concentrations at night compared to daytime. This rhythmicity was severely disrupted in Cd-exposed snails which exhibited highest CdMT gene transcription rates in the morning. Apart from diurnal rhythmicity, feeding activity also had a strong impact on CdMT gene expression. Although underlying mechanisms are not completely understood, it is clear that factors increasing MT expression variability have to be considered when using MT mRNA quantification as a biomarker for environmental stressors.

  19. Tracking the diurnal signal of plant water uptake through the hydrologic system

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Hassler, Sibylle; Heidbüchel, Ingo; Weiler, Markus; Simard, Sonia; Güntner, Andreas; Heinrich, Ingo

    2015-04-01

    Plant water uptake during summer is characterized by strong diurnal fluctuations. As a result a diurnal sink term is imposed on catchment storage, affecting the unsaturated zone, sometimes the saturated zone and even streamflow. Detecting this signal and understanding its propagation through the hydrological system may help to better quantify eco-hydrological connectivity. The extent and strength of the propagation of this signal from plant to soil to ground- and stream water was investigated with a unique setup of 46 field sites in Luxemburg and 15 field sites in Germany. These sites cover a range of geologies, soils, topographies and types of vegetation. Vegetation types include grassland, pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 3-5 soil moisture profiles, matrix potential, piezometers and sapflow sensors (as proxy for plant water uptake) as well as standard climate data. At sites with access to a stream, discharge or water level is also recorded. Signal strength (amplitude of diurnal fluctuations) can thus be traced through the system and gives an indication of the physical sphere of influence of plant water uptake i.e. the "eco-hydro-connectivity". Temporal dynamics of signal strength furthermore suggest a shifting spatial distribution of root water uptake with time. The analysis of time lags (or phase shifts) between daily fluctuations in temperature, radiation, sapflow, soil water, groundwater and streamflow gives further insights into the processes driving and propagating these signals and inter-site comparison allows for the investigation of local controls.

  20. Diurnal and circadian regulation of a melatonin receptor, MT1, in the golden rabbitfish, Siganus guttatus.

    PubMed

    Park, Yong-Ju; Park, Ji-Gweon; Hiyakawa, Nanae; Lee, Young-Don; Kim, Se-Jae; Takemura, Akihiro

    2007-01-15

    The golden rabbitfish Siganus guttatus is a reef fish with a restricted lunar-synchronized spawning rhythmicity and releases gametes simultaneously around the first quarter moon period during the spawning season. In order to understand the molecular aspects of the "circa" rhythms in this species, the full-length melatonin receptor (MT1) cDNA was cloned, and its diurnal/circadian regulation was examined. The full-length MT1 cDNA (1257 bp) contained an open reading frame that encodes a protein of 350 amino acids; this protein is highly homologous to MT1 of nonmammalian species. A high expression of MT1 mRNA with a day-night difference was observed in the whole brain, retina, liver, and kidney. When diurnal variations in MT1 mRNA expression in the retina and whole brain were examined using real-time quantitative RT-PCR, an increase in the mRNA expression was observed during nighttime in both tissues under conditions of light/dark, constant darkness, and constant light. This suggests that MT1 mRNA expression is under circadian regulation. The expression of MT1 mRNA in the cultured pineal gland also showed diurnal variations with high expression levels during nighttime; this suggests that the increased expression level observed in the whole brain is partially of pineal origin. Alternation of light conditions in the pineal gland cultures resulted in the changes in melatonin release into the culture medium as well as MT1 mRNA expression in the pineal gland. The present results suggest that melatonin and its receptors play an important role in the exertion of daily and circadian variations in the neural tissues.

  1. Physiological, Diurnal and Stress-Related Variability of Cadmium-Metallothionein Gene Expression in Land Snails

    PubMed Central

    Pedrini-Martha, Veronika; Niederwanger, Michael; Kopp, Renate; Schnegg, Raimund; Dallinger, Reinhard

    2016-01-01

    The terrestrial Roman snail Helix pomatia has successfully adapted to strongly fluctuating conditions in its natural soil habitat. Part of the snail’s stress defense strategy is its ability to express Metallothioneins (MTs). These are multifunctional, cysteine-rich proteins that bind and inactivate transition metal ions (Cd2+, Zn2+, Cu+) with high affinity. In Helix pomatia a Cadmium (Cd)-selective, inducible Metallothionein Isoform (CdMT) is mainly involved in detoxification of this harmful metal. In addition, the snail CdMT has been shown to also respond to certain physiological stressors. The aim of the present study was to investigate the physiological and diurnal variability of CdMT gene expression in snails exposed to Cd and non-metallic stressors such as desiccation and oxygen depletion. CdMT gene expression was upregulated by Cd exposure and desiccation, whereas no significant impact on the expression of CdMT was measured due to oxygen depletion. Overall, Cd was clearly more effective as an inducer of the CdMT gene expression compared to the applied non-metallic stressors. In unexposed snails, diurnal rhythmicity of CdMT gene expression was observed with higher mRNA concentrations at night compared to daytime. This rhythmicity was severely disrupted in Cd-exposed snails which exhibited highest CdMT gene transcription rates in the morning. Apart from diurnal rhythmicity, feeding activity also had a strong impact on CdMT gene expression. Although underlying mechanisms are not completely understood, it is clear that factors increasing MT expression variability have to be considered when using MT mRNA quantification as a biomarker for environmental stressors. PMID:26935042

  2. Circadian Kinetics of Cell Cycle Progression in Adult Neurogenic Niches of a Diurnal Vertebrate.

    PubMed

    Akle, Veronica; Stankiewicz, Alexander J; Kharchenko, Vasili; Yu, Lili; Kharchenko, Peter V; Zhdanova, Irina V

    2017-02-15

    The circadian system may regulate adult neurogenesis via intracellular molecular clock mechanisms or by modifying the environment of neurogenic niches, with daily variation in growth factors or nutrients depending on the animal's diurnal or nocturnal lifestyle. In a diurnal vertebrate, zebrafish, we studied circadian distribution of immunohistochemical markers of the cell division cycle (CDC) in 5 of the 16 neurogenic niches of adult brain, the dorsal telencephalon, habenula, preoptic area, hypothalamus, and cerebellum. We find that common to all niches is the morning initiation of G1/S transition and daytime S-phase progression, overnight increase in G2/M, and cycle completion by late night. This is supported by the timing of gene expression for critical cell cycle regulators cyclins D, A2, and B2 and cyclin-dependent kinase inhibitor p20 in brain tissue. The early-night peak in p20, limiting G1/S transition, and its phase angle with the expression of core clock genes, Clock1 and Per1, are preserved in constant darkness, suggesting intrinsic circadian patterns of cell cycle progression. The statistical modeling of CDC kinetics reveals the significant circadian variation in cell proliferation rates across all of the examined niches, but interniche differences in the magnitude of circadian variation in CDC, S-phase length, phase angle of entrainment to light or clock, and its dispersion. We conclude that, in neurogenic niches of an adult diurnal vertebrate, the circadian modulation of cell cycle progression involves both systemic and niche-specific factors.SIGNIFICANCE STATEMENT This study establishes that in neurogenic niches of an adult diurnal vertebrate, the cell cycle progression displays a robust circadian pattern. Common to neurogenic niches located in diverse brain regions is daytime progression of DNA replication and nighttime mitosis, suggesting systemic regulation. Differences between neurogenic niches in the phase and degree of S-phase entrainment to the

  3. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    USGS Publications Warehouse

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.; Bird, David M.; Varland, Daniel E.; Negro, Juan Jose

    1996-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.

  4. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    USGS Publications Warehouse

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.

    1994-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 40 species of diurnal raptors observed in ten affected areas, including raptors considered as forest interior species and some open country species utilizing the man-made openings inside the forest for roosting and foraging.

  5. Soil moisture sensing with aircraft observations of the diurnal range of surface temperature

    NASA Technical Reports Server (NTRS)

    Schmugge, T. J.; Blanchard, B.; Anderson, A.; Wang, V.

    1977-01-01

    Aircraft observations of the surface temperature were made by measurements of the thermal emission in the 8-14 micrometers band over agricultural fields around Phoenix, Arizona. The diurnal range of these surface temperature measurements were well correlated with the ground measurement of soil moisture in the 0-2 cm layer. The surface temperature observations for vegetated fields were found to be within 1 or 2 C of the ambient air temperature indicating no moisture stress. These results indicate that for clear atmospheric conditions remotely sensed surface temperatures are a reliable indicator of soil moisture conditions and crop status.

  6. Diurnal and seasonal mood vary with work, sleep, and daylength across diverse cultures.

    PubMed

    Golder, Scott A; Macy, Michael W

    2011-09-30

    We identified individual-level diurnal and seasonal mood rhythms in cultures across the globe, using data from millions of public Twitter messages. We found that individuals awaken in a good mood that deteriorates as the day progresses--which is consistent with the effects of sleep and circadian rhythm--and that seasonal change in baseline positive affect varies with change in daylength. People are happier on weekends, but the morning peak in positive affect is delayed by 2 hours, which suggests that people awaken later on weekends.

  7. General atmospheric circulation driven by polar and diurnal surface temperature variations.

    NASA Technical Reports Server (NTRS)

    Bohachevsky, I. O.

    1973-01-01

    Described is a global circulation model for the Venus atmosphere that includes the effects of both polar cooling and diurnal temperature variation. It is based on a linearized Boussinesq approximation and boundary conditions derived from theoretical and empirical considerations. The time-dependent, three-dimensional flow field is deduced without any a priori assumptions about its configuration. Results show that the mean atmospheric motions are essentially zonal in a narrow belt near the equator and change to become meridional over most of the globe. The circulation pattern is not symmetrical and rotates about the polar axis of the planet with the period of the solar day.

  8. [Temporal distribution of diurnal rapacious birds in "Playón de Mismaloya" Reservation, Jalisco, Mexico].

    PubMed

    Hernández Vázquez, S; Durand Martínez, B S; Esparza Salas, R; Valadez González, C

    2000-12-01

    Diurnal raptors were counted monthly in the "Playón de Mismaloya", reserve, Jalisco, Mexico, from November 1997 to October 1998. We identified 11 species; eight of them migrants, one resident and two resident with migrant populations. The highest increase in total number of individuals was from December to March, influenced mainly by the presence of Caracara polancus (Crested Caracara), Falco sparverius (American Kestrel) and Pandion haliaetus (Osprey). The two former species were observed frequently in open areas, where they could detect prey more easily, while ospreys were found only in estuaries, lagoons and beach, where food was available.

  9. Measurement of diurnal and semidiurnal rotational variations and tidal parameters of Earth

    NASA Technical Reports Server (NTRS)

    Herring, Thomas A.; Dong, Danan

    1994-01-01

    We discuss the determination of diurnal and semidiurnal variations in the rotation rate and the direction of rotation axis of Earth from the analysis of 8 years of very long baseline interferometry (VLBI) data. This analysis clearly show that these variations are largely periodic and tidally driven; that is, the periods of the variations correspond to the periods of the largest lunar and solar tides. For rotation rate variations, expressed in terms of changes in universal time (UT), the tidal lines with the largest observed signals are O1 (amplitude 23.5 microseconds in time (microseconds), period 25.82 solar hours); KL (18.9 microseconds, 23.93 hours); M2 (17.9 microseconds, 12.54 hours); and S2 (8.6 microseconds, 12.00 hours). For variations in the direction of the rotation axis (polar motion), significant signals exist in the retrograde semidiurnal band at the M2 and S2 tides (amplitudes 265 and 119 microarc seconds (microarc seconds, respectively); the prograde diurnal band at the O1, K1, and P1 tides (amplitudes 199, 152, and 60 microarc seconds, respectively); and the prograde semidiurnal band at the M2 and K2 tides (amplitudes 58 and 39 microarc seconds, respectively). Variations in the retrograde diurnal band are represented by corrections with previous estimates except that a previously noted discrepancy in the 13.66-day nutation (corresponding to the O1 tide) is largely removed in this new analysis. We estimate that the standard deviations of these estimates are 1.0 microseconds for the UT1 variations and 14-16 microarc seconds for the polar motion terms. These uncertainties correspond to surface displacements of approximately 0.5 mm. From the analysis of atmospheric angular momentum data we conclude that variations in UT1 excited by the atmosphere with subdaily periods are small (approximately 1 microsecond). We find that the average radial tidal displacements of the VLBI sites in the diurnal band are largely consistent with known deficiencies in current

  10. Diurnal Weather Cycles at the Tropical Treeline in the North American Monsoon Region

    NASA Astrophysics Data System (ADS)

    Biondi, F.

    2007-12-01

    High elevation atmospheric processes in the North American Monsoon region were investigated using half-hour weather data collected from May 22nd, 2001 to March 21st, 2007 at Nevado de Colima, Mexico (19° 35' N, 103° 37' W, 3760 m a.s.l.). After briefly expanding on temporal changes, which were first described by Biondi et al. 2005, I investigate diurnal weather cycles using the entire period of record. During the monsoon, precipitation falls mostly in the afternoon (from 12:00 to 20:00), with a peak around 17:00. Barometric pressure follows a regular wave pattern in all months, with a high at noon in between two lows, one around 5:30 and one between 17:00 and 19:00. Since barometric pressure is higher during the wet season, and the lows are found in all months, the afternoon low is not related to precipitation; rather it may help convective processes during the monsoon season. The diurnal pressure waves correspond to changes in wind speed, but it is unclear if turbulence drives the changes in pressure, as suggested by other authors. In particular, the amplitude of the atmospheric wave is greater in the dry season than in the wet season, in contrast to what was observed at high elevations in the Alps. The diurnal cycle of air temperature shows maxima during the spring, as the increased cloudiness during the summer wet season reduces incoming short wave radiation and its direct outcome, maximum air temperature. The dry season is characterized by greater excursions in air temperature, since the interval between maxima and minima is larger at all hours of the day. Soil temperature (especially the minima) is higher during the wet season, and shows an afternoon peak, most likely related to precipitation. Both minimum and maximum soil temperatures are at their lowest level around noon. Atmospheric vapor and vapor pressure deficit follow opposite patterns, as expected according to the season and the diurnal cycle of precipitation. These data provide a unique baseline for

  11. The diurnal cycle of rainfall over New Guinea in convection-permitting WRF simulations

    NASA Astrophysics Data System (ADS)

    Hassim, M. E. E.; Lane, T. P.; Grabowski, W. W.

    2016-01-01

    In this study, we examine the diurnal cycle of rainfall over New Guinea using a series of convection-permitting numerical simulations with the Weather Research and Forecasting (WRF) model. We focus our simulations on a period of suppressed regional-scale conditions (February 2010) during which local diurnal forcings are maximised. Additionally, we focus our study on the occurrence and dynamics of offshore-propagating convective systems that contribute to the observed early-morning rainfall maximum north-east of New Guinea.

    In general, modelled diurnal precipitation shows good agreement with satellite-observed rainfall, albeit with some timing and intensity differences. The simulations also reproduce the occurrence and variability of overnight convection that propagate offshore as organised squall lines north-east of New Guinea. The occurrence of these offshore systems is largely controlled by background conditions. Days with offshore-propagating convection have more middle tropospheric moisture, larger convective available potential energy, and greater low-level moisture convergence. Convection has similar characteristics over the terrain on days with and without offshore propagation.

    The offshore-propagating convection manifests via a multi-stage evolutionary process. First, scattered convection over land, which is remnant of the daytime maximum, moves towards the coast and becomes reorganised near the region of coastal convergence associated with the land breeze. The convection then moves offshore in the form of a squall line at ˜ 5 ms-1. In addition, cool anomalies associated with gravity waves generated by precipitating land convection propagate offshore at a dry hydrostatic gravity wave speed (of ˜ 15 ms-1) and act to destabilise the coastal/offshore environment prior to the arrival of the squall line. Although the gravity

  12. Diurnal Cycle of Convection and Interaction with the Large-Scale Circulation

    NASA Technical Reports Server (NTRS)

    Salby, Murry

    2002-01-01

    The science in this effort was scheduled in the project's 3rd and 4th years, after a long record of high-resolution Global Cloud Imagery (GCI) had been produced. Unfortunately, political disruptions that interfered with this project led to its funding being terminated after only two years of support. Nevertheless, the availability of intermediate data opened the door to a number of important scientific studies. Beyond considerations of the diurnal cycle addressed in this grant, the GCI wakes possible a wide range of studies surrounding convection, cloud and precipitation. Several are already underway with colleagues in the US and abroad, who have requested the GCI.

  13. Convective Cloud and Rainfall Processes Over the Maritime Continent: Simulation and Analysis of the Diurnal Cycle

    NASA Astrophysics Data System (ADS)

    Gianotti, Rebecca L.

    The Maritime Continent experiences strong moist convection, which produces significant rainfall and drives large fluxes of heat and moisture to the upper troposphere. Despite the importance of these processes to global circulations, current predictions of climate change over this region are still highly uncertain, largely due to inadequate representation of the diurnally-varying processes related to convection. In this work, a coupled numerical model of the land-atmosphere system (RegCM3-IBIS) is used to investigate how more physically-realistic representations of these processes can be incorporated into large-scale climate models. In particular, this work improves simulations of convective-radiative feedbacks and the role of cumulus clouds in mediating the diurnal cycle of rainfall. Three key contributions are made to the development of RegCM3-IBIS. Two pieces of work relate directly to the formation and dissipation of convective clouds: a new representation of convective cloud cover, and a new parameterization of convective rainfall production. These formulations only contain parameters that can be directly quantified from observational data, are independent of model user choices such as domain size or resolution, and explicitly account for subgrid variability in cloud water content and nonlinearities in rainfall production. The third key piece of work introduces a new method for representation of cloud formation within the boundary layer. A comprehensive evaluation of the improved model was undertaken using a range of satellite-derived and ground-based datasets, including a new dataset from Singapore's Changi airport that documents diurnal variation of the local boundary layer height. The performance of RegCM3-IBIS with the new formulations is greatly improved across all evaluation metrics, including cloud cover, cloud liquid water, radiative fluxes and rainfall, indicating consistent improvement in physical realism throughout the simulation. This work

  14. Diurnal redistribution of human lymphocytes and their temporal associations with salivary cortisol.

    PubMed

    Trifonova, Slavena T; Zimmer, Jacques; Turner, Jonathan D; Muller, Claude P

    2013-06-01

    Immune cell trafficking is crucial for surveillance and effector functions of the immune system. Circadian rhythms of the hypothalamic-pituitary-adrenal (HPA) axis and of cortisol have been implicated in circadian redistribution of circulating lymphocytes and granulocytes. However, information regarding the diurnal redistribution of immune cells and their temporal correlations with cortisol is scarce. In this study, we investigated the diurnal redistribution of T, B, and natural killer (NK) cell subsets in relation to the endogenous cortisol rhythm. Saliva and blood samples were collected every 15 min over an 8-h period. Salivary-free cortisol was measured by enzyme-linked immunosorbent assay (ELISA). Surface markers (CD3, CD19, CD8, CD56, CD16, KIR) were measured in whole blood samples by 6-color flow cytometry and cell subsets quantified as a percentage of the total lymphocyte population. To study associations between the diurnal cortisol rhythm and the redistribution of T, B, and NK cells, we calculated cross-correlations with lag periods of 15 min. The salivary cortisol levels showed the typical diurnal variations with a significant morning cortisol awakening response (CAR) peaking around 07:30 h followed by an afternoon nadir. Whereas B cells remained stable throughout the 8 h, T cells (CD3 + CD8+ and CD3 + CD8-) showed a significant positive cross-correlation with cortisol levels when a delay of 30-105 min was taken into account. This was followed by a negative correlation covering a period of 165-285 min after the cortisol peak. Conversely, NK cells showed an initial negative correlation at 45-105 min, followed by a positive correlation at 120-285 min. The major CD56 + CD16+ subset and the CD56 - CD16+ population showed similar temporal correlation profiles. The minor CD56 + CD16- NK cell subset showed no temporal changes. The major NK subset (CD56 + CD16+) contains cells with higher cytolytic activity (KIR+) cells, whereas the single

  15. Diurnal habitat use of American woodcock wintering along the Atlantic coast

    USGS Publications Warehouse

    Krementz, D.G.; Pendleton, G.W.

    1994-01-01

    The long-term decline of the American woodcock (Scolopax minor) population led us to investigate diurnal habitat use with radiotelemetry on the wintering grounds. Sites included the coastal plain of Georgia (1989-1991), South Carolina (1988-1989), and Virginia (1991-1992). Habitat use was not explained by age, sex, or date during the winter, but individuals used habitat differently (P < 0.05). Only shrubland was preferred at all sites in all years. Pine plantations of various ages were used according to availability, but usually less often than expected, while bottomland hardwoods and pine - hardwoods were used more often than expected.

  16. Circadian Kinetics of Cell Cycle Progression in Adult Neurogenic Niches of a Diurnal Vertebrate

    PubMed Central

    Stankiewicz, Alexander J.; Kharchenko, Vasili; Yu, Lili; Kharchenko, Peter V.

    2017-01-01

    The circadian system may regulate adult neurogenesis via intracellular molecular clock mechanisms or by modifying the environment of neurogenic niches, with daily variation in growth factors or nutrients depending on the animal's diurnal or nocturnal lifestyle. In a diurnal vertebrate, zebrafish, we studied circadian distribution of immunohistochemical markers of the cell division cycle (CDC) in 5 of the 16 neurogenic niches of adult brain, the dorsal telencephalon, habenula, preoptic area, hypothalamus, and cerebellum. We find that common to all niches is the morning initiation of G1/S transition and daytime S-phase progression, overnight increase in G2/M, and cycle completion by late night. This is supported by the timing of gene expression for critical cell cycle regulators cyclins D, A2, and B2 and cyclin-dependent kinase inhibitor p20 in brain tissue. The early-night peak in p20, limiting G1/S transition, and its phase angle with the expression of core clock genes, Clock1 and Per1, are preserved in constant darkness, suggesting intrinsic circadian patterns of cell cycle progression. The statistical modeling of CDC kinetics reveals the significant circadian variation in cell proliferation rates across all of the examined niches, but interniche differences in the magnitude of circadian variation in CDC, S-phase length, phase angle of entrainment to light or clock, and its dispersion. We conclude that, in neurogenic niches of an adult diurnal vertebrate, the circadian modulation of cell cycle progression involves both systemic and niche-specific factors. SIGNIFICANCE STATEMENT This study establishes that in neurogenic niches of an adult diurnal vertebrate, the cell cycle progression displays a robust circadian pattern. Common to neurogenic niches located in diverse brain regions is daytime progression of DNA replication and nighttime mitosis, suggesting systemic regulation. Differences between neurogenic niches in the phase and degree of S-phase entrainment to

  17. Semi-diurnal seiching in a shallow, micro-tidal lagoonal estuary

    NASA Astrophysics Data System (ADS)

    Luettich, Richard A.; Carr, Sarah D.; Reynolds-Fleming, Janelle V.; Fulcher, Crystal W.; McNinch, Jesse E.

    2002-07-01

    Analysis of current meter data in the Neuse River Estuary (NRE) associates over half of the along channel velocity variance with roughly the semi-diurnal frequency band. Velocity in this frequency range is episodic, has a typical magnitude of 10 cm s-1 and often reaches twice this speed. The NRE is a sub-estuary of the Albemarle-Pamlico Estuarine System (APES), which is the second largest estuarine complex and the largest lagoonal estuary in the United States. The astronomical tide in the NRE is negligible, owing to the APES's virtual isolation from the coastal ocean by the North Carolina Outer Banks barrier island chain. The episodic nature of the velocity signal together with the lack of an astronomical tide suggest that the semi-diurnal signal in the NRE is generated within the APES/NRE, presumably due to meteorological forcing. In the absence of a tidal current, this motion plays a significant role in determining the position and strength of the salt wedge, the thickness of the diffusive bottom boundary layer and the overall dispersion characteristics of the system. The episodic nature of the semi-diurnal signal encouraged us to pursue the use of nonstationary timeseries analysis techniques in the present study. We found wavelet analysis to be a highly effective technique for discriminating times when the semi-diurnal motion was strong and for identifying a predominant 13.2 h period in the along channel component of both 10-week wintertime and 10-week summertime current meter records. Model runs using idealized wind forcing to excite the vertically integrated version of the ADCIRC finite element circulation model indicated that the APES has a natural mode oscillation period of 13.2 h, an average "seiche depth" of 3.5 m and a "seiche length" of 139 km. This length is close to that of the long axis of Pamlico Sound, although the depth is approximately 25 percent less than the sound's 4.5 m mean bathymetric depth. Model runs using observed winds from Cape Hatteras

  18. The diurnal cycle of rainfall over New Guinea in convection-permitting WRF simulations

    NASA Astrophysics Data System (ADS)

    Hassim, M. E. E.; Lane, T. P.; Grabowski, W. W.

    2015-07-01

    In this study, we examine the diurnal cycle of rainfall over New Guinea using a series of convection-permitting numerical simulations with the Weather Research and Forecasting (WRF) model. We focus our simulations on a period of suppressed regional-scale conditions (February 2010) during which local diurnal forcings are maximised. Additionally, we focus our study on the occurrence and dynamics of offshore propagating convective systems that contribute to the observed early-morning rainfall maximum north-east of New Guinea. In general, modelled diurnal precipitation shows good agreement with satellite-observed rainfall, albeit with some timing and intensity differences. The simulations also reproduce the occurrence and variability of overnight convection that propagate offshore as organised squall lines north-east of New Guinea. The occurrence of these offshore systems is largely controlled by background conditions. Days with offshore propagating convection have more middle tropospheric moisture, larger CAPE and greater low-level moisture convergence. Convection has similar characteristics over the terrain on days with and without offshore propagation. The offshore propagating convection manifests via a multi-stage evolutionary process. First, scattered convection over land, which is remnant of the daytime maximum, moves towards the coast and becomes re-organised near the region of coastal convergence associated with the land breeze. The convection then moves offshore in the form of a squall line at ~5 m s-1. In addition, cool anomalies associated with gravity waves generated by precipitating land convection propagate offshore at a dry hydrostatic gravity wave speed (of ~15 m s-1), and act to destabilise the coastal/offshore environment prior to the arrival of the squall line. Although the gravity wave does not appear to initiate the convection or control its propagation, it should contribute to its longevity and maintenance. The results highlight the importance of

  19. Why is there a diurnal cycle of precipitation over the oceans?

    NASA Technical Reports Server (NTRS)

    Randall, David A.

    1989-01-01

    Using the Colorado State University general circulation model, simulated diurnal and semidiurnal variability of precipitation has been analyzed. At least four mechanisms have been proposed to account for the observed daily oscillations of precipitations over the ocean: direct radiation convection, radiation-dynamics-convection interactions, remote influence of the continents, and atmospheric tidal forces. Results indicate that neither land-sea contrasts nor cloudiness are necessary to produce daily variations of precipitations over the oceans. Clear-sky radiative effects, cloud-radiative effects, and the remote influence of the continents all turn out to play a role.

  20. A framework for global diurnally-resolved observations of Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Ghent, D.; Remedios, J.; Pinnock, S.

    2013-12-01

    Land surface temperature (LST) is the radiative skin temperature of the land, and is one of the key parameters in the physics of land-surface processes on regional and global scales. Being a key boundary condition in land surface models, which determine the surface to atmosphere fluxes of heat, water and carbon; thus influencing cloud cover, precipitation and atmospheric chemistry predictions within Global models, the requirement for global diurnal observations of LST is well founded. Earth Observation satellites offer an opportunity to obtain global coverage of LST, with the appropriate exploitation of data from multiple instruments providing a capacity to resolve the diurnal cycle on a global scale. Here we present a framework for the production of global, diurnally resolved, data sets for LST which is a key request from users of LST data. We will show how the sampling of both geostationary and low earth orbit data sets could conceptually be employed to build combined, multi-sensor, pole-to-pole data sets. Although global averages already exist for individual instruments and merging of geostationary based LST is already being addressed operationally (Freitas, et al., 2013), there are still a number of important challenges to overcome. In this presentation, we will consider three of the issues still open in LST remote sensing: 1) the consistency amongst retrievals; 2) the clear-sky bias and its quantification; and 3) merging methods and the propagation of uncertainties. For example, the combined use of both geostationary earth orbit (GEO) and low earth orbit (LEO) data, and both infra-red and microwave data are relatively unexplored but are necessary to make the most progress. Hence this study will suggest what is state-of-the-art and how considerable advances can be made, accounting also for recent improvements in techniques and data quality. The GlobTemperature initiative under the Data User Element of ESA's 4th Earth Observation Envelope Programme (2013

  1. Investigation of diurnal variability of water vapor in Enceladus' plume by the Cassini ultraviolet imaging spectrograph

    NASA Astrophysics Data System (ADS)

    Hansen, C. J.; Esposito, L. W.; Aye, K.-M.; Colwell, J. E.; Hendrix, A. R.; Portyankina, G.; Shemansky, D.

    2017-01-01

    An occultation of ɛ Orionis by Enceladus' plume was observed with Enceladus at an orbital longitude near apoapsis in order to investigate whether water vapor flow is modulated diurnally, similar to ice particles. The occultation showed that the bulk water vapor emanating from Enceladus changes little with orbital position. The amount of gas in at least one supersonic jet increased significantly, implying that the increase in the number of particles lofted at apoapsis could be due to more gas coming from the supersonic jets and not the overall gas flux from the tiger stripe fissures that cross Enceladus' south polar region.

  2. Diurnal variation of stratospheric chlorine monoxide - A critical test of chlorine chemistry in the ozone layer

    NASA Technical Reports Server (NTRS)

    Solomon, P. M.; De Zafra, R.; Parrish, A.; Barrett, J. W.

    1984-01-01

    Ground-based observations of a mm-wave spectral line at 278 GHz have yielded stratospheric chlorine monoxide column density diurnal variation records which indicate that the mixing ratio and column density of this compound above 30 km are about 20 percent lower than model predictions based on 2.1 parts/billion of total stratospheric chlorine. The observed day-to-night variation is, however, in good agreement with recent model predictions, both confirming the existence of a nighttime reservoir for chlorine and verifying the predicted general rate of its storage and retrieval.

  3. Cosmic ray solar diurnal anisotropy and transport coefficients for two Hale cycles

    NASA Astrophysics Data System (ADS)

    Modzelewska, Renata; Ygbuhay, R. C.; Ahluwalia, H. S.; Alania, Michael

    The data from the global network of several neutron monitors, ion chambers, and directional muon telescopes at Nagoya are used to compute the east-west, north-south, and radial components of the solar diurnal anisotropy of galactic cosmic rays for 1965-2011. The ratios of the mean free paths are derived parallel (K||) and perpendicular (K⊥) to the mean interplanetary magnetic field as well as the heliospheric radial gradient (Gr). The preliminary results for the timelines of α (= K⊥/ K||), Gr, their rigidity dependence are reported and their correlations with the solar activity for the positive and negative sectors of the solar polar magnetic field are discussed.

  4. Lidar Investigations of Atmospheric Boundary Layer Clouds over Coastal Environment and its Diurnal Evolution

    NASA Astrophysics Data System (ADS)

    Mishra, Manoj; Rajeev, Kunjukrishnapillai; Nair, Anish Kumar M.

    Over the high pressure region, diurnal evolution of atmospheric boundary layer (ABL) leads to the development of fair weather clouds, which in turn play an important role in modulating the thermodynamic structure of ABL, radiation balance at surface, and further development of ABL. As they usually cap the ABL, aerosol-cloud interaction in these clouds are expected to be quite large. Notwithstanding their importance, characteristics of the ABL clouds, their diurnal evolution and the resulting feedback are least explored. Major objectives of this study are to: (i) quantify the diurnal evolution of fair-weather ABL clouds and their characteristics (in terms of their altitude of occurrence, physical thickness and optical depth) based on multi-year (2008-2011) Micropulse Lidar observations at the coastal station, Thumba (8.5(°) N, 77(°) E), and (ii) explore the potential impact of these clouds in modulating the downwelling shortwave radiative flux at surface and further development of ABL. Altitude of occurrence of ABL clouds is found to undergo significant diurnal variation during the development of convective ABL (CABL). Typically, the ABL cloud base increases from <500 m at ˜09 LT to >1500 m at ˜12 LT. Base altitude of the ABL clouds is rather steady during the afternoon, associated with the stabilization of CABL development. Clouds in the nocturnal ABL (NABL) generally occur at the altitude of the preceding afternoon CABL height. Simultaneous occurrence of clouds in the thermal internal boundary layer (TIBL) and developed CABL/residual layer (RL) are also observed, through they are less frequent. The TIBL clouds are distinctly separated from those formed at the top of CABL/RL. Base heights of clouds are distinctly lower in TIBL and evolving CABL compared to those in developed CABL and RL, though their mean physical thickness are comparable (typically ˜250m). Optically thin clouds dominate the TIBL, compared to the other three regimes. Reduction in the

  5. The Mars Diurnal CO2 Cycle as Observed in the Tharsis Region.

    NASA Astrophysics Data System (ADS)

    Titus, T. N.; Cushing, G. E.

    2014-12-01

    The Mars atmosphere is composed of 95% CO2, 25% of which is cycled through the seasonal CO2 ice caps annually. During the polar night, surface temperatures drop to ~145 K and CO2 ice can begin to directly condense. Also, atmospheric temperatures can drop even lower, allowing for the formation of CO2 snow. During the spring, the CO2 ice sublimes thus completing the annual CO2 cycle. While significant study has been conducted to characterize and model the annual CO2 cycle, little has been done to investigate the possibility of a diurnal CO2 cycle.There are two general locations where the diurnal exchange of surface CO2 ice with the atmosphere can occur: (1) the higher elevations of the Tharsis region and (2) the edges of the seasonal polar caps. This presentation will focus on the Tharsis region. The low surface thermal inertia, due to a thick layer of dust, and the low atmospheric pressure of the Tharsis region allow for diurnal temperature ranges from at or near the CO2 frost temperature (~140 K at 2 mbar) during pre-dawn hours to temperatures above the triple point of water during mid-day. The Mars Global Surveyor Thermal Emission Spectrometer showed evidence of CO2 ice deposition near the summit of Olympus Mons at 2 am local time. Spectra from the coldest data observed are generally flat through the 25 μm region, suggesting slab or coarse grained CO2 ice. The 15 μm region of the spectra shows a warm atmosphere, suggesting that the formation of CO2 snow is unlikely. The Mars Odyssey Thermal Emission Imaging System showed consistently that much of the surface is at or near the frost point of CO2, suggesting the possible widespread presence of CO2 ice deposits during the pre-dawn hours.Simple energy balance considerations suggest that a nightly CO2 deposit that completely sublimes away shortly after dawn, could be as thick as 1.6 kg/m3 (~1 mm if deposit is slab ice with no porosity). Further constraints on the details of the Tharsis diurnal CO2 cycle will be

  6. A framework for global diurnally-resolved observations of Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Ghent, Darren; Remedios, John

    2014-05-01

    Land surface temperature (LST) is the radiative skin temperature of the land, and is one of the key parameters in the physics of land-surface processes on regional and global scales. Being a key boundary condition in land surface models, which determine the surface to atmosphere fluxes of heat, water and carbon; thus influencing cloud cover, precipitation and atmospheric chemistry predictions within Global models, the requirement for global diurnal observations of LST is well founded. Earth Observation satellites offer an opportunity to obtain global coverage of LST, with the appropriate exploitation of data from multiple instruments providing a capacity to resolve the diurnal cycle on a global scale. Here we present a framework for the production of global, diurnally resolved, data sets for LST which is a key request from users of LST data. We will show how the sampling of both geostationary and low earth orbit data sets could conceptually be employed to build combined, multi-sensor, pole-to-pole data sets. Although global averages already exist for individual instruments and merging of geostationary based LST is already being addressed operationally (Freitas, et al., 2013), there are still a number of important challenges to overcome. In this presentation, we will consider three of the issues still open in LST remote sensing: 1) the consistency amongst retrievals; 2) the clear-sky bias and its quantification; and 3) merging methods and the propagation of uncertainties. For example, the combined use of both geostationary earth orbit (GEO) and low earth orbit (LEO) data, and both infra-red and microwave data are relatively unexplored but are necessary to make the most progress. Hence this study will suggest what is state-of-the-art and how considerable advances can be made, accounting also for recent improvements in techniques and data quality. The GlobTemperature initiative under the Data User Element of ESA's 4th Earth Observation Envelope Programme (2013

  7. Evaluation of the diurnal variation of near-surface temperature and winds from WRF numerical simulations over complex terrain

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Pace, C.; Pu, Z.

    2011-12-01

    Near-surface atmospheric conditions, especially the temperature and winds, are characterized by their diurnal variations. Accurate representation and forecast of the diurnal variations are the essential components of numerical modeling and weather prediction. However, it is commonly challenging to accurately simulate and predict diurnal variations of near-surface atmospheric conditions over complex terrain, especially over the mountainous areas. In this study we evaluate the diurnal variation of near-surface temperature and winds from the numerical simulations generated by mesoscale community Weather Research and Forecasting (WRF) model. The model simulated surface temperature at 2-meter height and winds at 10-meter height are compared with these observations from surface mesonet observations in several different weather scenarios (winter inversion, cold front and low-level jet etc.) over the Inter-mountain West of US. Preliminary results show large discrepancies between model generated diurnal variations and observations in some cases. The mechanism and causes of these differences are further investigated. Implications of these results for model improvement and data assimilation are also discussed.

  8. The contribution of the pineal gland on daily rhythms and masking in diurnal grass rats, Arvicanthis niloticus.

    PubMed

    Shuboni, Dorela D; Agha, Amna A; Groves, Thomas K H; Gall, Andrew J

    2016-07-01

    Melatonin is a hormone rhythmically secreted at night by the pineal gland in vertebrates. In diurnal mammals, melatonin is present during the inactive phase of the rest/activity cycle, and in primates it directly facilitates sleep and decreases body temperature. However, the role of the pineal gland for the promotion of sleep at night has not yet been studied in non-primate diurnal mammalian species. Here, the authors directly examined the hypothesis that the pineal gland contributes to diurnality in Nile grass rats by decreasing activity and increasing sleep at night, and that this could occur via effects on circadian mechanisms or masking, or both. Removing the pineal gland had no effect on the hourly distribution of activity across a 12:12 light-dark (LD) cycle or on the patterns of sleep-like behavior at night. Masking effects of light at night on activity were also not significantly different in pinealectomized and control grass rats, as 1h pulses of light stimulated increases in activity of sham and pinealectomized animals to a similar extent. In addition, the circadian regulation of activity was unaffected by the surgical condition of the animals. Our results suggest that the pineal gland does not contribute to diurnality in the grass rat, thus highlighting the complexity of temporal niche transitions. The current data raise interesting questions about how and why genetic and neural mechanisms linking melatonin to sleep regulatory systems might vary among mammals that reached a diurnal niche via parallel and independent pathways.

  9. Diurnal patterns of gas-exchange and metabolic pools in tundra plants during three phases of the arctic growing season

    PubMed Central

    Patankar, Rajit; Mortazavi, Behzad; Oberbauer, Steven F; Starr, Gregory

    2013-01-01

    Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24-h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light-saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process-based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets. PMID:23467719

  10. Longitudinal associations between diurnal cortisol slope and alcohol use across adolescence: a seven-year prospective study.

    PubMed

    Ruttle, Paula L; Maslowsky, Julie; Armstrong, Jeffrey M; Burk, Linnea R; Essex, Marilyn J

    2015-06-01

    A large body of research has linked hypothalamic-pituitary-adrenal (HPA) axis function and alcohol consumption, including work suggesting that flatter diurnal cortisol slopes are associated with greater alcohol use. A lack of longitudinal studies and a focus on adult and alcoholic populations leaves unclear whether such associations are also present in younger, non-clinical populations and whether flatter diurnal slopes are a consequence of or preexisting risk factor for alcohol use; however, theory suggests such associations may be mutually reinforcing. In a longitudinal, community sample of 200 (55% female) adolescents, the current study demonstrates that flatter diurnal cortisol slope at age 11 predicts higher levels of alcohol use from ages 15-18, and that heavier alcohol use in turn predicts further flattening of diurnal cortisol rhythm at age 18.5. This is the first study to demonstrate a longitudinal chain of associations between diurnal cortisol slope and alcohol use. Findings support contemporary theoretical models of the neurobiological processes underlying alcohol use and can inform future research on risk factors for and consequences of underage drinking.

  11. Diurnal patterns of gas-exchange and metabolic pools in tundra plants during three phases of the arctic growing season.

    PubMed

    Patankar, Rajit; Mortazavi, Behzad; Oberbauer, Steven F; Starr, Gregory

    2013-02-01

    Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24-h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light-saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process-based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets.

  12. The associations between adolescent sleep, diurnal cortisol patterns and cortisol reactivity to dexamethasone suppression test.

    PubMed

    Pesonen, Anu-Katriina; Martikainen, Silja; Kajantie, Eero; Heinonen, Kati; Wehkalampi, Karoliina; Lahti, Jari; Strandberg, Timo; Räikkönen, Katri

    2014-11-01

    Information on the associations between objectively measured sleep and hypothalamic-pituitary-adrenal axis function in early adolescence is scarce. We examined associations between average sleep duration and quality (sleep efficiency and wake after sleep onset) over 8 days with actigraphs and (1) diurnal cortisol patterns and (2) cortisol reactivity to a low-dose (3 μg/kg) overnight dexamethasone suppression test (DST) in a birth cohort born in 1998 (N=265 participants, mean age 12.3 years, SD=0.5). We also explored (3) if sleep duration and quality were affected the nights after the DST exposure. Cortisol was measured during 2 days, and participants were exposed to dexamethasone in the evening of first day. In boys, short sleep duration was associated with higher cortisol upon awakening and lower cortisol awakening response (CAR; P<0.05 and P<0.01). Long sleep duration in boys associated with higher CAR (P<0.02). Lower sleep quality in boys associated with lower CAR, but fell slightly short of significance (P<0.06). In girls, no significant associations were detected. Sleep quantity and quality were not associated with responses to the DST. There were no effects of DST on sleep (P>0.15 in between-subject analyses). The average sleep patterns showed associations with diurnal cortisol patterns during early adolescence, but only in boys. Sleep was not associated with cortisol reactivity to DST and the exogenous corticosteroid exposure did not affect sleep significantly.

  13. Modeling the Diurnal Tides in the MLT Region with the Doppler Spread Parameterization of Gravity Waves

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Chan, K. L.; Trob, D.; Porter, H. C.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Special Session: SA03 The mesosphere/lower thermosphere region: Structure, dynamics, composition, and emission. Ground based and satellite observations in the upper mesosphere and lower thermosphere (MLT) reveal large seasonal variations in the horizontal wind fields of the diurnal and semidiurnal tides. To provide an understanding of the observations, we discuss results obtained with our Numerical Spectral Model (NMS) that incorporates the gravity wave Doppler Spread Parameterization (DSP) of Hines. Our model reproduces many of the salient features observed, and we discuss numerical experiments that delineate the important processes involved. Gravity wave momentum deposition and the seasonal variations in the tidal excitation contribute primarily to produce the large equinoctial amplitude maxima in the diurnal tide. Gravity wave induced variations in eddy viscosity, not accounted for in the model, have been shown by Akmaev to be important too. For t