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. Load Leveling Battery System Costs

    Energy Science and Technology Software Center (ESTSC)

    1994-10-12

    SYSPLAN evaluates capital investment in customer side of the meter load leveling battery systems. Such systems reduce the customer's monthly electrical demand charge by reducing the maximum power load supplied by the utility during the customer's peak demand. System equipment consists of a large array of batteries, a current converter, and balance of plant equipment and facilities required to support the battery and converter system. The system is installed on the customer's side of themore » meter and controlled and operated by the customer. Its economic feasibility depends largely on the customer's load profile. Load shape requirements, utility rate structures, and battery equipment cost and performance data serve as bases for determining whether a load leveling battery system is economically feasible for a particular installation. Life-cycle costs for system hardware include all costs associated with the purchase, installation, and operation of battery, converter, and balance of plant facilities and equipment. The SYSPLAN spreadsheet software is specifically designed to evaluate these costs and the reduced demand charge benefits; it completes a 20 year period life cycle cost analysis based on the battery system description and cost data. A built-in sensitivity analysis routine is also included for key battery cost parameters. The life cycle cost analysis spreadsheet is augmented by a system sizing routine to help users identify load leveling system size requirements for their facilities. The optional XSIZE system sizing spreadsheet which is included can be used to identify a range of battery system sizes that might be economically attractive. XSIZE output consisting of system operating requirements can then be passed by the temporary file SIZE to the main SYSPLAN spreadsheet.« less

  3. Load leveling on industrial refrigeration systems

    NASA Astrophysics Data System (ADS)

    Bierenbaum, H. S.; Kraus, A. D.

    1982-01-01

    A computer model was constructed of a brewery with a 2000 horsepower compressor/refrigeration system. The various conservation and load management options were simulated using the validated model. The savings available for implementing the most promising options were verified by trials in the brewery. Result show that an optimized methodology for implementing load leveling and energy conservation consisted of: (1) adjusting (or tuning) refrigeration systems controller variables to minimize unnecessary compressor starts, (2) The primary refrigeration system operating parameters, compressor suction pressure, and discharge pressure are carefully controlled (modulated) to satisfy product quality constraints (as well as in-process material cooling rates and temperature levels) and energy evaluating the energy cost savings associated with reject heat recovery, and (4) a decision is made to implement the reject heat recovery system based on a cost/benefits analysis.

  4. Load leveling on industrial refrigeration systems. Final report

    SciTech Connect

    Bierenbaum, H.S.; Kraus, A.D.

    1982-01-01

    This project addressed the problem of developing, validating, and demonstrating an optimized methodology for maximizing the benefits of load levelling, energy conservation through efficiency improvements, and reject heat recovery on large, energy intensive industrial compressor systems. A typical industrial food processing plant, a brewery, with a 2000 horsepower compressor/refrigeration system was used as a model facility and as a site for demonstration and validation of strategies developed. The approach used in this work was to construct a computer model of the facility and its energy systems and validate the model against actual data. The next step was to simulate the various conservation and load management options using the validated model. Finally, the savings available for implementing the most promising options were verified by trials in the brewery. Results showed that an optimized methodology for implementing load leveling and energy conservation consisted of first adjusting (or tuning) refrigeration systems controller variables - gain and reset - to minimize unnecessary compressor starts. Second, the primary refrigeration system operating parameters, compressor suction pressure, and discharge pressure are carefully controlled (modulated) to satisfy product quality constraints (as well as in-process material cooling rates and temperature levels) and simultaneously improve energy efficiency and peak demand. Third, energy cost savings for recovery of heat from the reject side of the refrigeration system are estimated using the newly determined compressor operating conditions as a basis for evaluating the energy cost savings associated with reject heat recovery. Fourth, a decision is made to implement the reject heat recovery system based on a cost/benefits analysis.

  5. Diurnal variations of Titan

    NASA Astrophysics Data System (ADS)

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Mueller-Wodarg, I. C. F.; Kasprzak, W. T.; Waite, J. H.

    2009-04-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1,000 and 1,400 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from 8 close encounters of the Cassini spacecraft with Titan. Though there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ~700 cm-3 below ~1,300 km. Such a plateau is associated with the combination of distinct diurnal variations of light and heavy ions. Light ions (e.g. CH5+, HCNH+, C2H5+) show strong diurnal variation, with clear bite-outs in their nightside distributions. In contrast, heavy ions (e.g. c-C3H3+, C2H3CNH+, C6H7+) present modest diurnal variation, with significant densities observed on the nightside. We propose that the distinctions between light and heavy ions are associated with their different chemical loss pathways, with the former primarily through "fast" ion-neutral chemistry and the latter through "slow" electron dissociative recombination. The INMS data suggest day-to-night transport as an important source of ions on Titan's nightside, to be distinguished from the conventional scenario of auroral ionization by magnetospheric particles as the only ionizing source on the nightside. This is supported by the strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes. We construct a time-dependent ion chemistry model to investigate the effects of day-to-night transport on the ionospheric structures of Titan. The predicted diurnal variation has similar general characteristics to those observed, with some apparent discrepancies which could be reconciled by imposing fast horizontal thermal winds in Titan's upper atmosphere.

  6. Diurnal polar motion

    NASA Technical Reports Server (NTRS)

    Mcclure, P.

    1973-01-01

    An analytical theory is developed to describe diurnal polar motion in the earth which arises as a forced response due to lunisolar torques and tidal deformation. Doodson's expansion of the tide generating potential is used to represent the lunisolar torques. Both the magnitudes and the rates of change of perturbations in the earth's inertia tensor are included in the dynamical equations for the polar motion so as to account for rotational and tidal deformation. It is found that in a deformable earth with Love's number k = 0.29, the angular momentum vector departs by as much as 20 cm from the rotation axis rather than remaining within 1 or 2 cm as it would in a rigid earth. This 20 cm separation is significant in the interpretation of submeter polar motion observations because it necessitates an additional coordinate transformation in order to remove what would otherwise be a 20 cm error source in the conversion between inertial and terrestrial reference systems.

  7. Diurnal patterns of blowing sand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diurnal pattern of blowing sand results from a complex process that involves an interaction between solar heating, thermal instability, atmospheric turbulence, wind strength, and surface threshold conditions. During the day, solar heating produces thermal instability, which enhances the convect...

  8. 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.

  9. Proposal of Load Leveling Model for Implementing Mass Customization in Automobile Industry

    NASA Astrophysics Data System (ADS)

    Matsumoto, Shimpei; Ueno, Nobuyuki; Okuhara, Koji; Ishii, Hiroaki

    Along with the diversification of customers' demand, there is an urgent need for a business model to realize the mass customization in automobile industry. When the volume and quantity of orders from customers is changing dynamically, it is difficult for a maker to realize both productivity and a variety of customers' specification by itself. So, we propose a new collaboration between the maker and supplier in a supply chain structure about ”load leveling” to supplier. Firstly, we describe a framework about the cost structure in accordance with ”load leveling” to the supplier and estimate the increased cost. Specially, we formulate the volume about load leveling and the maker's increased cost. Next, we derive the total increased cost estimator in the supply chain and analyze it. Finally, we get the optimal load leveling with minimum increased cost and get some information about designing the supply chain structure between the maker and supplier to realize mass customization.

  10. Large lead/acid batteries for frequency regulation, load levelling and solar power applications

    NASA Astrophysics Data System (ADS)

    Wagner, R.

    Lead/acid batteries are suitable for a multitude of utility applications. This paper presents some examples where large lead/acid batteries have been used for frequency regulation, load levelling and solar power applications. The operational experiences are given together with a discussion about the design and technical specialities of these batteries. In 1986, a 17 MW/14 MWh battery was installed at BEWAG in Berlin which, at that time, was the largest lead/acid battery in the world. Designed to strengthen Berlin's 'island' system, it was used since the beginning of 1987 for frequency regulation and spinning reserve. In December 1993, when Berlin was connected to the electricity grid, frequency regulation was no longer required but the battery was still used for spinning reserve. For many years, the industrial battery plant of Hagen in Soest has used a large lead/acid battery for load levelling. The experience gained during more than ten years shows that load levelling and peak shaving can be a marked benefit for customers and utilities with regard to reducing their peak demand. In the summer of 1992, a 216 V and 2200 Ah lead/acid battery with positive tubular plates and gelled electrolyte was installed at a solar power plant in Flanitzhutte, a small village in the south of Germany which is not connected to the electricity grid. A report is given of the first years of use and includes a discussion about the best charge strategy for such gel batteries when used for solar power applications.

  11. 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...

  12. Diurnal variations of Titan's ionosphere

    NASA Astrophysics Data System (ADS)

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Müller-Wodarg, I. C. F.; Cravens, T. E.; Kasprzak, W. T.; Waite, J. H.

    2009-06-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1000 and 1300 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from eight close encounters of the Cassini spacecraft with Titan. Although there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ˜700 cm-3 below ˜1300 km. Such a plateau is a combined result of significant depletion of light ions and modest depletion of heavy ones on Titan's nightside. We propose that the distinctions between the diurnal variations of light and heavy ions are associated with their different chemical loss pathways, with the former primarily through “fast” ion-neutral chemistry and the latter through “slow” electron dissociative recombination. The strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes suggests a scenario in which the ions created on Titan's dayside may survive well to the nightside. The observed asymmetry between the dawn and dusk ion density profiles also supports such an interpretation. We construct a time-dependent ion chemistry model to investigate the effect of ion survival associated with solid body rotation alone as well as superrotating horizontal winds. For long-lived ions, the predicted diurnal variations have similar general characteristics to those observed. However, for short-lived ions, the model densities on the nightside are significantly lower than the observed values. This implies that electron precipitation from Saturn's magnetosphere may be an additional and important contributor to the densities of the short-lived ions observed on Titan's nightside.

  13. Diurnal variation of mesospheric ozone

    NASA Astrophysics Data System (ADS)

    Vaughan, G.

    1982-03-01

    Four Petrel rockets were flown from South Uist on October 2, 1979, to investigate the ozone concentration variation predicted by photochemical models between day and night in the mesosphere by means of interference filters that defined an approximately 10 nm bandwidth. The first two rockets contained photometers with wavebands centered at 265 and 290 nm, while the last two employed a single waveband at 265 nm. Results show significant diurnal variation above 54 km, which exceeds a factor of 2 above 65 km and reaches a factor of 10 between night and sunrise at 90 km.

  14. 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

  15. Life evaluation of valve-regulated lead-acid batteries for load-leveling applications

    NASA Astrophysics Data System (ADS)

    Deluca, W. H.; Miller, J. F.; Webster, C. E.; Hogrefe, R. L.

    Argonne National Laboratory (ANL) has initiated a test program to evaluate the suitability of valve-regulated lead-acid (VRLA) batteries for use in deep-discharge cycling applications. The program includes the examination of VRLA batteries of the gelled-electrolyte design and the absorbed-electrolyte type. This work is sponsored by the Electric Power Research Institute (EPRI) and the International Lead Zinc Research Organization (ILZRO). While VRLA batteries have found use in standby and uninterruptable power source applications, insufficient data are available to determine their performance and life in repetitive cycling applications. The objectives of the ANL test plan are: (1) to use accelerated testing techniques to obtain evidence within a 6 month test period that indicate an expected life in a utility operating environment; (2) to determine VRLA battery life within a 2 to 3 year time period under conditions (temperature and depth-of-discharge) that closely simulate those encountered in load-leveling operations; and (3) to assess the applicability and usefulness of accelerated testing procedures for deep-discharge cycling applications.

  16. 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.

  17. Diurnal variations of tropical cyclone precipitationin

    NASA Astrophysics Data System (ADS)

    Wu, Q.

    2015-12-01

    Using 15 years of satellite-measured precipitation data and tropical cyclone (TC) information, this study estimates the diurnal variations of TC precipitation in its inner core and outer rainbands. It is found that for both weak (tropical storms to category 1 TCs) and strong (categories 2-5 TCs) storms over all six TC basins, the TC precipitation reaches its daily maximum in the morning, but the mean rain rate and diurnal variations are larger in the inner core than in the outer rainbands. With increasing radial distance from the TC center, the diurnal amplitude of precipitation decreases, and the peak time appears progressively later. The outward propagation of diurnal signals from the TC center dominates as an internal structure of the TC convective systems. For all basins examined, the diurnal precipitation maximum within the inner core of a strong storm occurs earlier than the maximum observed in non-TC precipitation; the same result is not found for the outer rainbands.

  18. 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.

  19. 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.

  20. Levetiracetam: Probably Associated Diurnal Frequent Urination.

    PubMed

    Ju, Jun; Zou, Li-Ping; Shi, Xiu-Yu; Hu, Lin-Yan; Pang, Ling-Yu

    2016-01-01

    Diurnal frequent urination is a common condition in elementary school children who are especially at risk for associated somatic and behavioral problems. Levetiracetam (LEV) is a broad-spectrum antiepileptic drug that has been used in both partial and generalized seizures and less commonly adverse effects including psychiatric and behavioral problems. Diurnal frequent urination is not a well-known adverse effect of LEV. Here, we reported 2 pediatric cases with epilepsy that developed diurnal frequent urination after LEV administration. Case 1 was a 6-year-old male patient who presented urinary frequency and urgency in the daytime since the third day after LEV was given as adjunctive therapy. Symptoms increased accompanied by the raised dosage of LEV. Laboratory tests and auxiliary examinations did not found evidence of organic disease. Diurnal frequent urination due to LEV was suspected, and then the drug was discontinued. As expected, his frequency of urination returned to normal levels. Another 13-year-old female patient got similar clinical manifestations after oral LEV monotherapy and the symptoms became aggravated while in stress state. Since the most common causes of frequent micturition had been ruled out, the patient was considered to be diagnosed with LEV-associated psychogenic frequent urination. The dosage of LEV was reduced to one-third, and the frequency of urination was reduced by 60%. Both patients got the Naranjo score of 6, which indicated that LEV was a "probable" cause of diurnal frequent urination. Although a definite causal link between LEV and diurnal urinary frequency in the 2 cases remains to be established, we argue that diurnal frequent urination associated with LEV deserves clinician's attention. PMID:26938751

  1. Colour vision in diurnal and nocturnal hawkmoths.

    PubMed

    Kelber, Almut; Balkenius, Anna; Warrant, Eric J

    2003-08-01

    Diurnal and nocturnal hawkmoths (Sphingidae, Lepidoptera) have three spectral types of receptor sensitive to ultraviolet, blue and green light. As avid flower visitors and pollinators, they use olfactory and visual cues to find and recognise flowers. Moths of the diurnal species Macroglossum stellatarum and the nocturnal species Deilephila elpenor, Hyles lineata and Hyles gallii use and learn the colour of flowers. Nocturnal species can discriminate flowers at starlight intensities when humans and honeybees are colour-blind. M. stellatarum can use achromatic, intensity-related cues if colour cues are absent, and this is probably also true for D. elpenor. Both species can recognise colours even under a changed illumination colour. PMID:21680465

  2. Diurnally entrained anticipatory behavior in archaea.

    PubMed

    Whitehead, Kenia; Pan, Min; Masumura, Ken-ichi; Bonneau, Richard; Baliga, Nitin S

    2009-01-01

    By sensing changes in one or few environmental factors biological systems can anticipate future changes in multiple factors over a wide range of time scales (daily to seasonal). This anticipatory behavior is important to the fitness of diverse species, and in context of the diurnal cycle it is overall typical of eukaryotes and some photoautotrophic bacteria but is yet to be observed in archaea. Here, we report the first observation of light-dark (LD)-entrained diurnal oscillatory transcription in up to 12% of all genes of a halophilic archaeon Halobacterium salinarum NRC-1. Significantly, the diurnally entrained transcription was observed under constant darkness after removal of the LD stimulus (free-running rhythms). The memory of diurnal entrainment was also associated with the synchronization of oxic and anoxic physiologies to the LD cycle. Our results suggest that under nutrient limited conditions halophilic archaea take advantage of the causal influence of sunlight (via temperature) on O(2) diffusivity in a closed hypersaline environment to streamline their physiology and operate oxically during nighttime and anoxically during daytime. PMID:19424498

  3. 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

  4. 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. PMID:27222741

  5. 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.

  6. Diurnal behaviour of water on Mars

    NASA Technical Reports Server (NTRS)

    Flasar, F. M.; Goody, R. M.

    1976-01-01

    A numerical model of the diurnal transport of water across the Martian surface is developed. The atmospheric boundary layer is modeled in terms of local radiative-convective processes, and radiative effects of ice fogs near the surface are included. Diffusion of water in the ground is treated for the cases of adsorption and condensation. The model is applied to the diurnal variation of water vapor in the atmosphere as observed by Barker (1974). The morning rise in the amount of water vapor can be explained in terms of the evaporation of ground fogs. The evening decrease is compatible with the model if adsorption dominates in the soil. The average level of vapor concentration requires that the atmosphere above the boundary layer be relatively dry. The ground fogs persist until midmorning and should be observable. Some consequences of these conclusions are discussed.

  7. 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.

  8. The diurnal variability of marine stratocumulus clouds

    NASA Technical Reports Server (NTRS)

    Rogers, David P.; Olsen, Lola M.

    1990-01-01

    Observations of the diurnal variation of marine stratocumulus clouds obtained during July 1987 as part of the First ISCCP Regional Experiment are described. The observations show a clear diurnal signature in the structure of the cloud-topped marine boundary layer, with a large variation in the height of the cloud base, with lower heights observed at night. The observational results are numerically simulated using a 1D second-moment turbulence-closure model of Koracin and Rogers (1990) for a hydrostatically incompressible fluid. The model results indicate that the differential heating of the cloud layer promotes mixing in the upper part of the cloud and stabilizes the lower part of the layer.

  9. 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.

  10. 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.

  11. Space-Time Characteristics of Rainfall Diurnal Variations

    NASA Technical Reports Server (NTRS)

    Yang, Song; Kummerow, Chris; Olson, Bill; Smith, Eric A.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The space-time features of rainfall diurnal variation of precipitation are systematically investigated by using the Tropical Rainfall Measuring Mission (TRMM) precipitation products retrieved from TRMM microwave imager (TMI), precipitation radar (PR) and TMI/PR combined algorithms. Results demonstrate that diurnal variability of precipitation is obvious over tropical regions. The dominant feature of rainfall diurnal cycle over, ocean is that there is consistent rainfall peak in early morning, while there is a consistent rainfall peak in mid-late afternoon over land. The seasonal variation on intensity of rainfall diurnal cycle is clearly evidenced. Horizontal distributions of rainfall diurnal variations indicate that there is a clearly early-morning peak with a secondary peak in the middle-late afternoon in ocean rainfall at latitudes dominated by large-scale convergence and deep convection. There is also an analogous early-morning peak in land rainfall along with a stronger afternoon peak forced by surface heating. Amplitude analysis shows that the patterns and its evolution of rainfall diurnal cycle are very close to rainfall distribution pattern and its evolution. These results indicate that rainfall diurnal variations are strongly associated with large-scale convective systems and climate weather systems. Phase studies clearly present the regional and seasonal features of rainfall diurnal activities. Further studies on convective and stratiform rainfall show different characteristics of diurnal cycles. Their spatial and temporal variations of convective and stratiform rainfall indicate that mechanisms for rainfall diurnal variations vary with time and space.

  12. 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

  13. Plateau effects on diurnal circulation patterns

    SciTech Connect

    Reiter, E.R.; Tang, M.

    1984-04-01

    The diurnal variation of 850 mb heights, the detailed distribution of which could be assessed by the inclusion of surface data, and of resultant winds over, and in the vicinity of, the Great Basin reveals clearly a plateau-wind circulation during summer. This circulation reverses between day and night and appears to include the low-level jet stream over Texas and Oklahoma, as well as the time of occurrence of thunderstorms. This plateau circulation system interacts with local mountain-valley breeze systems. The thickness of the daytime inflow and nighttime outflow layer over the plateau is approximately 2 km. 19 references, 11 figures, 1 table.

  14. A thin-layer multistrip agarose gel electrophoresis apparatus for Ferguson plot analysis at the sub-microgram load level.

    PubMed

    Orbàn, L; Sullivan, J V; Chrambach, A

    1989-07-01

    A method for the simultaneous horizontal agarose gel electrophoresis on thin-layer strips of different gel concentrations was developed for the purpose of generating Ferguson plots at the sub-microgram load level. Seven independent gel strips on a common GelBond support were formed by filling channels created by a comb-shaped spacer (polycarbonate) in a vertical multistrip cassette. Electrophoresis on a horizontal Peltier-cooled surface employed commercial apparatus (E-C Apparatus Corp.) with a modified cover which is airtight and holds anodic and cathodic voltage measurement probes for each strip. The application of the apparatus to Ferguson plot analysis in a single experiment was exemplified on the RNA-containing turnip crinkle virus (TCV) at a load of 50 ng/gel strip, using an optimized silver staining method (a modification of a procedure of FMC Corp. BioProducts) for detection. Within the range of 3.5 to 12.5 V/cm, the plot was found to be independent of field strength. Mobility is also independent of the concentration of detergent (CHAPS) up to 10 mM. PMID:2809063

  15. 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.

  16. Diurnal variability of precipitation from TRMM measurements

    NASA Astrophysics Data System (ADS)

    Yang, Song; Smith, Eric A.; Kuo, Kwo-Sen

    2006-12-01

    This investigation focuses on developing a better understanding of the assorted mechanisms controlling the global distribution of diurnal rainfall variability. The horizontal distributions of precipitation's diurnal cycle, based on eight years of TRMM Microwave Imager (TMI) and TRMM Precipitation Radar (PR) measurements involving three TRMM standard algorithms, are analyzed in detail at various spatiotemporal scales. Results demonstrate the prominence of the late-evening to early-morning precipitation maxima over oceans and the mid- to late-afternoon maxima over continents, but also reveal a widespread distribution of secondary maxima occurring over both oceans and continents, maxima which generally mirror their counterpart regime's behavior. That is, many ocean regions exhibit clear-cut secondary afternoon precipitation maxima while many continental areas exhibit just as evident secondary morning maxima. Notably, this investigation represents the first comprehensive study of these secondary maxima and their widespread nature when analyzed using a global precipitation dataset. The characteristics of the secondary maxima are thoroughly mapped and described on a global grid. In addition, a Fourier harmonic decomposition scheme is used to examine detailed amplitude and phase properties of the primary and secondary maxima -- as well as tertiary and quartern modes. Accordingly, the advantages, ambiguities, and pitfalls resulting from using harmonic analysis are also examined.

  17. 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.

  18. DIURNAL VARIATIONS IN TRAFFIC FLOW AND CARBON MONOXIDE CONCENTRATIONS

    EPA Science Inventory

    Traffic count and carbon monoxide (CO) data for January and July from three states are compared in order to reveal any diurnal variations in the two measurements. The diurnal patterns for the 18 traffic count stations indicate that there are average patterns of traffic flow that ...

  19. 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.

  20. Diurnal periodicity of the flow of Alaska earthquakes

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    The Alaska earthquake catalog has been analyzed in detail to find and study the diurnal periodicity of earthquake events. For this purpose, a set of spatially and temporally homogeneous samples of earthquakes with the well-known magnitude of completeness ( M c) has been prepared. For each sample, the spectra have been considered, the average diurnal variations in the number of earthquakes have been calculated, and their amplitudes were determined. The average diurnal variations were compared. For representative earthquakes in Alaska, no significant diurnal variation has been found. In subrepresentative samples, either the diurnal variation is insignificant or the signal-to-noise ratio only slightly exceeds 1.3-1.9. The diurnal variation is significant (a signal-to-noise ratio of 2.0-4.5) only for the samples of weak earthquakes with magnitudes of no more than 1.4, which is 0.5 units less than the strong (i.e., guaranteed for the entire sample area) completeness threshold. The results are consistent with the hypothesis explaining the diurnal periodicity of earthquakes by noise-discrimination effects. However, a comparative analysis of the diurnal variation parameters estimated over a large number of spatially and temporally homogeneous samples of earthquakes in the Alaska, southern California, and Greece catalogs shows that all of these results cannot be explained by this model.

  1. 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.

  2. Thermospheric composition. [latitudinal, seasonal and diurnal variations

    NASA Technical Reports Server (NTRS)

    Carignan, G. R.

    1975-01-01

    The global view of the atmosphere provided by satellite observations and radar backscatter measurements has shown a pattern of composition variability resulting largely from dynamic processes. Important progress has been made in defining composition variability at 120 km, which has greatly improved models which previously had fixed boundary conditions at that altitude. The discovery of the early morning maximum in helium abundance and the better definition of diurnal variation in relative composition have provided a basis for more sophisticated dynamical models. Similarly, models of meridional wind systems have been developed which can account for the better-defined winter enhancements in helium and atomic oxygen. Finally, composition variability has indicated the presence of a high-latitude heat source which during periods of magnetic activity profoundly modifies the state of the atmosphere.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Diurnal Thermal Cycling Effects on Backscatter of Thin Sea Ice

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Kwok, R.; Yueh, S. H.; Gow, A. J.; Perovich, D. K.; Hsu, C. C.; Ding, K. H.; Kong, J. A.; Grenfell, T. C.

    1996-01-01

    To invesigate effects on polarimetric backscatter of sea ice grown under diurnal cycling conditions, we carried out an experiment inJanuary 1994 at the outdoor Geophysical Research Facility in the Cold Regions Research and Engineering Laboratory.

  8. 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.

  9. 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.

  10. Projected Increase in Diurnal and Inter-Diurnal Variations of European Summer Temperatures

    NASA Astrophysics Data System (ADS)

    Cattiaux, J.; Douville, H.; Schoetter, R.; Parey, S.; Yiou, P.

    2014-12-01

    The current European warming is expected to be associated with an increased temperature variability in summer, particularly at the daily time-scale. Such an increase would affect hot extremes and accentuate the societal and environmental impacts caused by the mean warming. Here we investigate future changes in the short-term variability of European summer temperatures using two indices that have been seldom documented so far: the variations within one day (diurnal temperature range, DTR) and the variations from one day to the next (inter-diurnal temperature variability, ITV). These rapid variations represent key issues for impact communities, in particular energy providers vulnerable to sudden surges in electricity demand. Besides, the ITV provides a measure of daily variability that is not disturbed by longer-term variations in the mean (e.g., seasonal cycle and/or a multi-year trend), whereas traditional measures such as standard deviation or variance are. We use 21st-century projections performed by 34 models of the CMIP5 ensemble under the three RCP 2.6, 4.5 and 8.5 scenarios. Models are evaluated over the present-day period against the E-OBS dataset. In Europe, both indices of summer temperature variability are projected to increase, with a rather good model agreement on the sign, while uncertainties remain on the amplitude. In particular, we show that extremely high day-to-day and/or diurnal temperature variations are expected to occur more frequently. We highlight the singularity of the European area, since ITV and DTR changes do not systematically coincide over other regions (e.g., the U.S). Then we investigate the physical processes underlying these ITV and DTR changes in the CMIP5 projections. The respective contributions of the summer drying of European soils, the reduction in cloud cover and the changes in large-scale dynamics are estimated. Finally, the possibility of reducing model uncertainties through constraints emerging from both present

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Diurnal variations in blood flow at optic nerve head and choroid in healthy eyes: diurnal variations in blood flow.

    PubMed

    Iwase, Takeshi; Yamamoto, Kentaro; Ra, Eimei; Murotani, Kenta; Matsui, Shigeyuki; Terasaki, Hiroko

    2015-02-01

    To investigate the diurnal variations of the ocular blood flow in healthy eyes using laser speckle flowgraphy (LSFG), and to determine the relationship of the diurnal variations between the ocular blood flow and other ocular parameters.This prospective cross-sectional study was conducted at Nagoya University Hospital. We studied 13 healthy volunteers whose mean age was 33.5 ± 7.6 years. The mean blur rate (MBR), expressing the relative blood flow, on the optic nerve head (ONH) and choroidal blood flow was determined by LSFG (LSFG-NAVI) every 3 hours from 6:00 to 24:00 hours. The intraocular pressure (IOP), choroidal thickness measured by enhanced depth imaging optical coherence tomography, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) in the brachial artery were also recorded. We evaluated the diurnal variations of the parameters and compared the MBR to the other parameters using a linear mixed model.The diurnal variations of the MBR on the ONH varied significantly with a trough at 9:00 hours and a peak at 24:00 hours (P < 0.001, linear mixed model). The MBR of choroid also had significant diurnal variations with a trough at 15:00 hours and a peak at 18:00 hours (P = 0.001). The IOP (P < 0.001), choroidal thickness (P < 0.001), SBP (P = 0.005), DBP (P = 0.001), and HR (P < 0.001) also had significant diurnal variations. Although the diurnal variation of the MBR on the ONH was different from the other parameters, that on the choroid was significantly and positively correlated with the DBP (P = 0.002), mean arterial pressure (P = 0.023), and mean ocular perfusion pressure (P = 0.047).We found significant diurnal variations in the ONH and choroidal blood flow. Although the ONH blood flow had its own diurnal variation because of strong autoregulation, the choroidal blood flow was more likely affected by systemic circulatory factors because of poor autoregulation. PMID:25674750

  18. Intimate partner violence and diurnal cortisol patterns in couples

    PubMed Central

    Kim, Hyoun K.; Tiberio, Stacey S.; Capaldi, Deborah M.; Shortt, Joann Wu; Squires, Erica C.; Snodgrass, J. Josh

    2014-01-01

    Summary This study examined whether physical intimate partner violence (IPV) victimization was associated with diurnal patterns of salivary cortisol in a community sample of 122 couples in their 30s from predominantly lower socioeconomic status backgrounds. Findings indicate that women with higher levels of victimization exhibited flatter patterns of diurnal cortisol characterized by both higher midday levels and more attenuated decreases in cortisol levels across the day, compared to women with lower levels of victimization. However, men's victimization was not associated with their diurnal cortisol levels. This study advances our understanding of the association between physical IPV victimization and dysregulated hypothalamic-pituitary-adrenal (HPA) axis functioning in women, which is likely to have further implications for their subsequent mental and physical health. PMID:25286224

  19. 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.

  20. 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.

  1. Phase reversal of the diurnal cycle in the midlatitude ionosphere

    NASA Astrophysics Data System (ADS)

    Liu, Huixin; Thampi, Smitha V.; Yamamoto, Mamoru

    The typical diurnal cycle of the midlatitude F region electron density consists of a midday maximum and a midnight minimum. However, a phase reversal of this diurnal cycle has been found to occur in three distinct regions on the globe. They are the East Asian (EA) region centered around (53N, 150E), the Northern Atlantic (NA) region centered around (45N, 50W) and the South Pacific (SP) region centered around (60S, 110W). The intensively reported Wed-dell Sea Anomaly falls inside the SP region. The phase reversal occurs during March-August in EA and NA regions, and between August and March in SP region, being most prominent in local summer. Furthermore, this diurnal anomaly is more pronounced at solar minimum than at solar maximum, and more pronounced in SP region than in NA and EA regions, in terms of larger diurnal magnitude and more months it lasts in a year. It is emphasized that the diurnal anomaly consists of not only a nighttime enhancement, but also a concurrent noontime depletion. Hence, midlatitude summer nighttime enhancements reported in previous studies are just part of this reversed diurnal cycle. The cause for the phase reversal involves several interplaying physical processes. Among these, the neutral wind combined with the geomagnetic field configuration plays a pivotal role. It generates a onewave longitudinal pattern at south-ern middle latitudes and a twowave pattern at northern middle latitudes, whose wave peaks correspond to the center of the SP, EA, and NA regions, respectively. The seasonal variation of neutral winds and downward motion of the ionization induced by thermal contraction of the ionosphere at sunset may largely control the occurring local time of the nighttime density enhancement and how long it persists in different months. The phase reversal occurs as a result of close ionneutral coupling. It is further noted that winter anomaly in the EA, NA, and SP regions is very weak or missing.

  2. Assimilating Satellite SST Observations into a Diurnal Cycle Model

    NASA Astrophysics Data System (ADS)

    Pimentel, S.; Haines, K.; Nichols, N. K.

    2006-12-01

    The wealth of satellite sea surface temperature (SST) data now available opens the possibility of large improvements in SST estimation. However the use of such data is not straight forward; a major difficulty in assimilating satellite observations is that they represent a near surface temperature, whereas in ocean models the top level represents the temperature at a greater depth. During the day, under favourable conditions of clear skies and calm winds, the near surface temperature is often seen to have a diurnal cycle that is picked up in satellite observations. Current ocean models do not have the vertical or temporal resolution to adequately represent this daytime warming. The usual approach is to discard daytime observations as they are considered diurnally `corrupted'. A new assimilation technique is developed here that assimilates observations into a diurnal cycle model. The diurnal cycle of SSTs are modelled using a 1-D mixed layer model with fine near surface resolution and 6 hourly forcing from NWP analyses. The accuracy of the SST estimates are hampered by uncertainties in the forcing data. The extent of diurnal SST warming at a particular location and time is predominately governed by a non-linear response to cloud cover and sea surface wind speeds which greatly affect the air-sea fluxes. The method proposed here combines infrared and microwave SST satellite observations in order to derive corrections to the cloud cover and wind speed values over the day. By adjusting the forcing, SST estimation and air-sea fluxes should be improved and are at least more consistent with each other. This new technique for assimilating SST data can be considered a tool for producing more accurate diurnal warming estimates.

  3. Diurnal Variability in Orthostatic Tachycardia: Implications for Postural Tachycardia Syndrome

    PubMed Central

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

    2011-01-01

    Patients with Postural Tachycardia Syndrome (POTS) have excessive orthostatic tachycardia (>30 bpm) when standing from a supine position. Heart rate (HR) and blood pressure (BP) are known to exhibit diurnal variability, but the role of diurnal variability in orthostatic changes of HR & BP is not known. In this study, we tested the hypothesis that there is diurnal variation of orthostatic HR & 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 & BP were obtained on the evening on the day of admission and in the following morning. Overall, standing HR was significantly higher in the morning than the evening (102±3 bpm [AM] vs. 93±2 bpm [PM]; P<0.001). Standing HR was higher in the morning in both POTS patients (108±4 bpm [AM] vs. 100±3 bpm [PM]; P=0.012) and controls (89±3 bpm [AM] vs. 80±2 bpm [PM]; P=0.005), when analyzed separately. There was no diurnal variability in orthostatic BP in POTS. More 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 to 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. PMID:21751966

  4. 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.

  5. 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

  6. 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

  7. Nonmigrating diurnal tides in the equatorial middle atmosphere

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.

    1991-01-01

    Data from the Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) are used to extend the analysis of diurnal tides in the middle atmosphere to include the zonally symmetric and eastward propagating components. These modes show vertical and meridional structures that are generally consistent with the predictions of linear tidal theory. The zonal and meridional wind fields are calculated from the tidal temperatures. Diurnal perturbations in LIMS temperature and derived winds agree well with equinoctial model calculations. Comparisons with day-night differences of radiosonde temperature and rocket winds show qualitative agreement in vertical structure and amplitude. The zonally symmetric and eastward migrating tidal components show a higher degree of temporal variability than the sun-synchronous component. These modes at times contribute substantially to the diurnal signal in wind and temperature, with combined amplitudes equal to or in excess of the amplitude of the main migrating diurnal tide. The observed vertical phase variations suggest that their forcing may originate below the stratosphere.

  8. Diurnal variation of diazinon volatilization: Soil moisture effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted to measure the effect of soil moisture on diazinon volatilization under typical semi-arid field conditions. The study comprised three experiments performed with differing soil moisture conditions. Over the course of each three day experiment, diurnal changes in volatiliz...

  9. PARALLEL EVALUATION OF CONSTANT AND DIURNAL FLOW TREATMENT SYSTEMS

    EPA Science Inventory

    Pilot plant studies were performed to evaluate the effects of an imposed diurnal flow pattern on a conventional activated sludge treatment plant. These results were compared against data generated on a similar system treating a constant flow. Effects on primary clarifier and fina...

  10. A model of the diurnal variation in lake surface temperature

    NASA Astrophysics Data System (ADS)

    Hodges, Jonathan L.

    Satellite measurements of water surface temperature can benefit several environmental applications such as predictions of lake evaporation, meteorological forecasts, and predictions of lake overturning events, among others. However, limitations on the temporal resolution of satellite measurements restrict these improvements. A model of the diurnal variation in lake surface temperature could potentially increase the effective temporal resolution of satellite measurements of surface temperature, thereby enhancing the utility of these measurements in the above applications. Herein, a one-dimensional transient thermal model of a lake is used in combination with surface temperature measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua and Terra satellites, along with ambient atmospheric conditions from local weather stations, and bulk temperature measurements to calculate the diurnal surface temperature variation for the five major lakes in the Savannah River Basin in South Carolina: Lakes Jocassee, Keowee, Hartwell, Russell, and Thurmond. The calculated solutions are used to obtain a functional form for the diurnal surface temperature variation of these lakes. Differences in diurnal variation in surface temperature between each of these lakes are identified and potential explanations for these differences are presented.

  11. 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...

  12. 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…

  13. DIURNAL WATER RELATIONS OF WALNUT TREES: IMPLICATIONS FOR REMOTE SENSING

    EPA Science Inventory

    Leaf water content (LWC), relative water content (RWC) and water potential (LWP) were measured as indicators of diurnal change in tree water status in an experimental walnut orchard receiving two irrigation treatments: 00% and 33% of potential evapotranspiration (PET). WP had the...

  14. 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.

  15. 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.

  16. DHC: a diurnal heat capacity program for microcomputers

    SciTech Connect

    Balcomb, J.D.

    1985-01-01

    A computer program has been developed that can predict the temperature swing in direct gain passive solar buildings. The diurnal heat capacity (DHC) program calculates the DHC for any combination of homogeneous or layered surfaces using closed-form harmonic solutions to the heat diffusion equation. The theory is described, a Basic program listing is provided, and an example solution printout is given.

  17. 40 CFR 86.133-96 - Diurnal emission test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Diurnal emission test. 86.133-96 Section 86.133-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New...

  18. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... diurnal emissions specified in 40 CFR 1048.105. (3) Recreational vehicles are not subject to diurnal... performance standards specified in Title 13 CCR § 2754(a) based on the applicable requirements specified in...

  19. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... diurnal emissions specified in 40 CFR 1048.105. (3) Recreational vehicles are not subject to diurnal... performance standards specified in Title 13 CCR § 2754(a) based on the applicable requirements specified in...

  20. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... diurnal emissions specified in 40 CFR 1048.105. (3) Recreational vehicles are not subject to diurnal... performance standards specified in Title 13 CCR § 2754(a) based on the applicable requirements specified in...

  1. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... diurnal emissions specified in 40 CFR 1048.105. (3) Recreational vehicles are not subject to diurnal... requirements specified in CP-902 and TP-902, including the requirements related to fuel caps in Title 13...

  2. 40 CFR 1060.105 - What diurnal requirements apply for equipment?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... diurnal emissions specified in 40 CFR 1048.105. (3) Recreational vehicles are not subject to diurnal... performance standards specified in Title 13 CCR § 2754(a) based on the applicable requirements specified in...

  3. 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

  4. 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.

    2015-08-01

    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.

  5. Diurnal regulation of hypothalamic kisspeptin is disrupted during mouse pregnancy.

    PubMed

    Yap, Cassandra C; Wharfe, Michaela D; Mark, Peter J; Waddell, Brendan J; Smith, Jeremy T

    2016-06-01

    Kisspeptin, the neuropeptide product of the Kiss1 gene, is critical in driving the hypothalamic-pituitary-gonadal (HPG) axis. Kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) and arcuate nucleus (Arc) of the hypothalamus mediate differential effects, with the Arc regulating negative feedback of sex steroids and the AVPV regulating positive feedback, vital for the preovulatory surge and gated under circadian control. We aimed to characterize hypothalamic Kiss1 and Kiss1r mRNA expression in nonpregnant and pregnant mice, and investigate potential circadian regulation. Anterior and posterior hypothalami were collected from C57BL/6J mice at diestrus, proestrus, and days 6, 10, 14, and 18 of pregnancy, at six time points across 24h, for real-time PCR analysis of gene expression. Analysis confirmed that Kiss1 mRNA expression in the AVPV increased at ZT13 during proestrus, with a luteinizing hormone surge observed thereafter. No diurnal regulation was seen at diestrus or at any stage of pregnancy. Anterior hypothalamic Avp mRNA expression exhibited no diurnal variation, but Avpr1a peaked at 12:00h during proestrus, possibly reflecting the circadian input from the suprachiasmatic nucleus to AVPV Kiss1 neurons. Rfrp (Npvf) expression in the posterior hypothalamus did not demonstrate diurnal variation at any stage. Clock genes Bmal1 and Rev-erbα were strongly diurnal, but there was little change between diestrus/proestrus and pregnancy. Our data indicate the absence of the circadian input to Kiss1 in pregnancy, despite high gestational estradiol levels and normal clock gene expression, and may suggest a disruption of a kisspeptin-specific diurnal rhythm that operates in the nonpregnant state. PMID:27068699

  6. 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.

  7. 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.

  8. Interannual and Intraseasonal Variability of the Diurnal Tide

    NASA Astrophysics Data System (ADS)

    Riggin, D. M.; Ortland, D. A.; Lieberman, R. S.; Oberheide, J.; Murayama, Y.; Hocking, W. K.; Vincent, R. A.; Reid, I. M.; Kumar, G. K.; Batista, P. P.; Clemesha, B. R.

    2013-12-01

    Temporal variations in the amplitude of the diurnal tide (DT) have been observed by radars with a seasonal dependence that is typically semiannual in the tropics. During some years the wind variation departs from the normal seasonal behavior with anomalously large amplitudes compared to most other years. This anomaly often takes the form of a greatly enhanced boreal spring equinoctal maximum. The boreal spring of 2008 is a example of this behavior. Diurnal amplitudes in the meridional winds are shown in the figure below for the first 6 months of 2008. Note that the diurnal tide undergoes a sharp increase in amplitude up to 80 ms-1 during this event. The characteristics of this event are diagnosed in a variety of global data sets. These include our own physics-based assimilation of SABER temperatures, and gridded analyses from the national weather services (NCAR/NCEP and ECMWF). Tidal amplitude variations are sometimes attributed to nonlinear interaction. However, this type of interaction would be expected to produce non-migrating tides, e.g., westward-2 or standing. SABER data show that the amplitude anomaly is mainly in the migrating DT. The global data sets allow us to explore properties of the anomaly, such as its origin, evolution in time, and associated momentum flux. In addition to this case study, we also investigate the general characteristics of DT interannual variability during the years of the SABER mission (2002-present). Diurnal tide momentum deposition plays a significant role in controlling the zonal mean wind in the mesosphere, We demonstrate its importance in driving the mesospheric semiannual oscillation (MSAO). Diurnal tide wind amplitudes in the meridional component observed at two radar sites, Rarotonga, Cook Islands (22.1°S, 159.8°W), and at Guanacaste, Costa Rica (10.3°N, 85.6°W).

  9. 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.

  10. 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.

  11. Phase reversal of the diurnal cycle in the midlatitude ionosphere

    NASA Astrophysics Data System (ADS)

    Liu, Huixin; Thampi, Smitha V.; Yamamoto, Mamoru

    2010-01-01

    The typical diurnal cycle of the midlatitude F region electron density consists of a midday maximum and a midnight minimum. However, a phase reversal of this diurnal cycle has been found to occur in three distinct regions on the globe. They are the East Asian (EA) region centered around (53°N, 150°E), the Northern Atlantic (NA) region centered around (45°N, 50°W) and the South Pacific (SP) region centered around (60°S, 110°W). The intensively reported Weddell Sea Anomaly falls inside the SP region. The phase reversal occurs during March-August in EA and NA regions, and between August and March in SP region, being most prominent in local summer. Furthermore, this diurnal anomaly is more pronounced at solar minimum than at solar maximum, and more pronounced in SP region than in NA and EA regions, in terms of larger diurnal magnitude and more months it lasts in a year. It is emphasized that the diurnal anomaly consists of not only a nighttime enhancement, but also a concurrent noontime depletion. Hence, midlatitude summer nighttime enhancements reported in previous studies are just part of this reversed diurnal cycle. The cause for the phase reversal involves several interplaying physical processes. Among these, the neutral wind combined with the geomagnetic field configuration plays a pivotal role. It generates a one-wave longitudinal pattern at southern middle latitudes and a two-wave pattern at northern middle latitudes, whose wave peaks correspond to the center of the SP, EA, and NA regions, respectively. The seasonal variation of neutral winds and downward motion of the ionization induced by thermal contraction of the ionosphere at sunset may largely control the occurring local time of the nighttime density enhancement and how long it persists in different months. The phase reversal occurs as a result of close ion-neutral coupling. It is further noted that winter anomaly in the EA, NA, and SP regions is very weak or missing.

  12. An initial estimate of the global distribution of diurnal variation in sea surface salinity

    NASA Astrophysics Data System (ADS)

    Fine, E. C.; Bryan, F. O.; Large, W. G.; Bailey, D. A.

    2015-05-01

    Diurnal variations in sea surface salinity (SSS) have been observed at a few selected locations with adequate in situ instrumentation. Such variations result primarily from imbalances between surface freshwater fluxes and vertical mixing of deeper water to the surface. New observations becoming available from satellite salinity remote sensing missions could help to constrain estimates of diurnal variations in air-sea exchange of freshwater, and provide insight into the processes governing diurnal variability of mixing processes in the upper ocean. Additionally, a better understanding of variation in near surface salinity is required to compare satellite measured SSS with in situ measurements at a few meters depth. The diurnal SSS variations should be reflected as differences between ascending and descending pass retrievals from the Aquarius and SMOS satellites; however, the diurnal signal can be masked by inadequacies of the geophysical corrections used in processing the satellite measurements. In this study, we quantify the expected range of diurnal SSS variations using a model developed for predicting diurnal sea surface temperature variations. We present estimates for the mean and variance of the global diurnal SSS cycle, contrasting it with the diurnal cycle of sea surface temperature. We find the SSS diurnal cycle can be significant throughout the tropics, with mean amplitudes of up to 0.1 psu in areas with heavy precipitation. Predicted maximum diurnal ranges approach 2 psu in select regions. Surface freshening in Aquarius salinity retrievals is shown to be larger for ascending than descending passes, consistent with the expectations from the model simulation.

  13. Do diurnal aerosol changes affect daily average radiative forcing?

    NASA Astrophysics Data System (ADS)

    Kassianov, Evgueni; Barnard, James; Pekour, Mikhail; Berg, Larry K.; Michalsky, Joseph; Lantz, Kathy; Hodges, Gary

    2013-06-01

    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 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.

  14. 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.

  15. Diurnal Variation of Plasma Bone Markers in Japanese Black Calves

    PubMed Central

    MATSUO, Asako; TOGASHI, Akira; SASAKI, Kouya; DEVKOTA, Bhuminand; HIRATA, Toh-ichi; YAMAGISHI, Norio

    2014-01-01

    ABSTRACT To evaluate diurnal variation of plasma bone markers, blood samples were collected from five calves at 2-hr intervals throughout a 24-hr period. Tartrate-resistant acid phosphatase isoform 5b (TRAP5b), carboxy-terminal collagen crosslinks of type-I collagen (CTX), hydroxyproline, bone specific alkaline phosphatase (BALP) and osteocalcin were measured. Cosinor analysis showed a significant rhythm in all bone markers. The acrophase of each bone marker appeared from the early to late morning. The percentage ratio of the amplitude to mesor and the within-subject variability for CTx and osteocalcin were significantly larger than those for TRAP5b and BALP. This marked diurnal variation in five bone markers suggested that the time of blood sampling should be fixed when studying bone marker concentrations in bovine plasma. PMID:24646502

  16. 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

  17. Central melanopsin projections in the diurnal rodent, Arvicanthis niloticus

    PubMed Central

    Langel, Jennifer L.; Smale, Laura; Esquiva, Gema; Hannibal, Jens

    2015-01-01

    The direct effects of photic stimuli on behavior are very different in diurnal and nocturnal species, as light stimulates an increase in activity in the former and a decrease in the latter. Studies of nocturnal mice have implicated a select population of retinal ganglion cells that are intrinsically photosensitive (ipRGCs) in mediation of these acute responses to light. ipRGCs are photosensitive due to the expression of the photopigment melanopsin; these cells use glutamate and pituitary adenylate cyclase-activating polypeptide (PACAP) as neurotransmitters. PACAP is useful for the study of central ipRGC projections because, in the retina, it is found exclusively within melanopsin cells. Little is known about the central projections of ipRGCs in diurnal species. Here, we first characterized these cells in the retina of the diurnal Nile grass rat using immunohistochemistry (IHC). The same basic subtypes of melanopsin cells that have been described in other mammals were present, but nearly 25% of them were displaced, primarily in its superior region. PACAP was present in 87.7% of all melanopsin cells, while 97.4% of PACAP cells contained melanopsin. We then investigated central projections of ipRGCs by examining the distribution of immunoreactive PACAP fibers in intact and enucleated animals. This revealed evidence that these cells project to the suprachiasmatic nucleus, lateral geniculate nucleus (LGN), pretectum, and superior colliculus. This distribution was confirmed with injections of cholera toxin subunit β coupled with Alexa Fluor 488 in one eye and Alexa Fluor 594 in the other, combined with IHC staining of PACAP. These studies also revealed that the ventral and dorsal LGN and the caudal olivary pretectal nucleus receive less innervation from ipRGCs than that reported in nocturnal rodents. Overall, these data suggest that although ipRGCs and their projections are very similar in diurnal and nocturnal rodents, they may not be identical. PMID:26236201

  18. The effects of an anticipated challenge on diurnal cortisol secretion.

    PubMed

    Wetherell, Mark A; Lovell, Brian; Smith, Michael A

    2015-01-01

    In healthy, non-challenged individuals, the secretion of cortisol typically follows a diurnal profile characterized by a peak in the period following waking (cortisol awakening response) and a gradual decline throughout the day. In addition, cortisol secretion is increased in response to acutely stressful stimuli, particularly stressors involving social evaluation. The current study is the first to assess the impact of an anticipated acute laboratory stressor upon the typical diurnal pattern of HPA activation and relationship to acute cortisol secretion. A sample of 23 healthy young adults provided salivary cortisol samples at four time points (immediately upon awakening, 30-min post-awakening, 1200 h and before bed) on 2 consecutive days. On the second day, participants attended the laboratory and undertook an anticipated acute socially evaluative stressor immediately following provision of their 1200 h saliva sample. Heart rate, blood pressure and mood were recorded immediately before and after the stressor and at 10 and 20 min post-stressor along with additional salivary cortisol samples. Typical patterns of cortisol secretion were observed on both days and exposure to the laboratory stressor was associated with the expected increases in cortisol, heart rate, blood pressure and negative mood. However, significant differences in diurnal cortisol secretion were observed between the two days with greater secretion, in particular, during the period following awakening, evident on the day of the anticipated laboratory stressor. Furthermore, secretion of cortisol during the period following awakening was positively related to secretion during the acute reactivity periods. This is the first study to integrate a laboratory stressor into a typical day and assess its impact on indices of diurnal cortisol secretion in an ambulatory setting. The current findings support the notion that the cortisol awakening response is associated with anticipation of the upcoming day

  19. Visualizing diurnal population change in urban areas for emergency management.

    PubMed

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

    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. PMID:21491706

  20. Moored surface buoy observations of the diurnal warm layer

    NASA Astrophysics Data System (ADS)

    Prytherch, J.; Farrar, J. T.; Weller, R. A.

    2013-09-01

    An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5-15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models.

  1. Why be diurnal? Or, why not be cathemeral?

    PubMed

    Hill, R A

    2006-01-01

    As a behavioural strategy, cathemerality is thought to confer considerable advantages by allowing animals to extend activity flexibly into either the diurnal or nocturnal phase in response to the prevailing ecological conditions. Factors such as temperature, access to food sources and minimising the risk of predation are all thought to be important in promoting cathemerality, although previous studies have produced inconsistent results. This paper adopts a different approach by first asking whether an obligate diurnal species, the chacma baboon (Papio hamadryas ursinus), exhibits seasonal variation in behavioural flexibility in response to annual cycles of day length. While short day lengths are an important constraint on the activity of the baboons at De Hoop Nature Reserve, South Africa, long summer days permit considerable flexibility in thermoregulatory response, diet selection and patterns of habitat choice. Given that baboons adapt flexibly in response to a relaxation of time constraints, the question thus arises as to why diurnal and nocturnal primates do not adopt cathemeral activity patterns when time is constrained? For baboons, the costs of predation appear to prohibit exploitation of the nocturnal phase and it is likely that such constraints are true of most primates. It thus follows that Madagascar's predatory environment must in some way permit or select for a cathemeral lifestyle. The importance of the predation by fossa (Cryptoprocta ferox) on the evolution of cathemerality is discussed. PMID:16415578

  2. 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.

  3. 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. PMID:25288753

  4. 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

  5. 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

  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 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

  8. CART peptide diurnal variations in blood and brain.

    PubMed

    Vicentic, Aleksandra

    2006-08-01

    The central role of CART peptide in feeding, drug abuse and stress has been widely researched however, CART's role in the peripheral system are less explored. CART peptide is present in a variety of peripheral tissues including sympathetic ganglion neurons, adrenal glands, gut, pancreas and blood. Studies that examined circulating CART demonstrated that the active fragment with a molecular weight of CART55-102 is present in the blood of rats and rhesus macaques. Interestingly, CART expression in these species exhibits a distinctive diurnal rhythm which correlates with the respective daily rhythms of corticosterone and feeding. In the rat, adrenalectomy significantly reduces blood CART levels and abolishes its daily rhythm while corticosterone replacement reinstates CART expression to control levels. In addition, direct administration of corticosterone significantly increases CART blood levels while administration of corticosterone synthesis blocker metyrapone, inhibits CART blood levels. These data suggest that the adrenal gland could be a source of blood CART and that glucocorticoids may play a role in the generation of CART's diurnal rhythm. Moreover, fuel availability may be important in the control of CART levels and its daily rhythm, since 24 h food restriction alters CART levels and abolishes its rhythm. In addition to blood, both CART peptide and mRNA exhibit food-dependent diurnal rhythm in discrete rat brain areas including the nucleus accumbens, amygdala and hypothalamus. Altogether, these findings suggest that CART is influenced by hypothalamic-pituitary-adrenal interactions and that it may play a role in multiple physiological processes possibly involving feeding, stress, reward and motivation. PMID:16697078

  9. 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.

  10. 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.

  11. Diurnal Variation of Meteorological Parameters in the Land Surface Interface

    NASA Astrophysics Data System (ADS)

    Pillai, J. S.

    A pilot land surface processes experiment was conducted at Anand, Gujarat, situated in the western part of India, from April to July 1995. The diurnal variation of air and soil temperature with respect to solar radiation was studied in two selected periods, one in summer and the other during monsoon. It was observed that during summer, there was a considerable lag in the temperature maxima with respect to solar radiation, as compared to the monsoon period. Also, in summer, when there was an increase in wind speed from near zero values in the early morning hours, the soil surface as well as the air temperature minima were raised.

  12. Behavior of the Sq Diurnal Magnetic Variation over Egypt

    NASA Astrophysics Data System (ADS)

    Ghamry, E.; Mahrous, A.; El-Hawary, R.; Yumoto, K.

    2011-12-01

    The diurnal variation of the solar quiet (Sq) in the geomagnetic north-south component (H) and geomagnetic eastwest component (D), along the Magnetic Data Acquisition System (MAGDAS) stations in Egypt during year 2009 have been studied. MAGDAS was successfully installed at two stations in Egypt Fayum (FYM) and Aswan (ASW). Several forms of Abnormal Quiet Days (AQDs) have been found in both of Sq (H) and Sq (D). These AQDs of Sq (H) are expected to be related to counter or reversed electrojet while AQDs of Sq (D) is presumably due to the currents of the (2, 3) mode.

  13. 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.

  14. Spatial and diurnal variations of storm heights in the East Asia summer monsoon: storm height regimes and large-scale diurnal modulation

    NASA Astrophysics Data System (ADS)

    Park, Myung-Sook; Lee, Myong-In; Kim, Hyerim; Im, Jungho; Yoo, Jung-Moon

    2016-02-01

    This study investigates the spatial and diurnal variation of storm height in the East Asia summer monsoon region using 13-year Tropical Rainfall Measuring Mission Precipitation Radar data. Precipitating storms are classified as shallow (<5 km), middle (5-10 km), and deep (>10 km) depending the height. Four different regimes are identified to characterize the region: the continental (CT) shallow regime over inland China with elevated terrain, the CT deep over the Chinese Plain, the coastal (CS) middle over the East China Sea and South Sea of Korea, and the CS shallow over the south coastal area of Japan. This regime separation reflects well the distinctive regional difference in the rainfall contribution by each storm type. The occurrence frequencies of shallow, middle, and deep storms exhibit pronounced diurnal variation as well, but with significant differences in the amplitude and phase across the regimes. These lead to a diversity in the diurnal variation of surface rainfall such as bimodal morning and late evening peaks in the two CT regimes and the single morning peak in the two CS regimes. Processes involved in the diurnal variation of storms are different across the regimes, indicating difference in the contributing role of surface heating, large-scale diurnal circulation, and diurnal propagations of convective systems. The storm height also affects the rain intensity. This study highlights that the East Asia summer monsoon has distinctive sub-regional variation of the storm height distribution, thereby providing unique differences in the rainfall amount, intensity, and the diurnal variation.

  15. A stochastic differential equation model of diurnal cortisol patterns.

    PubMed

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

    2001-03-01

    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. PMID:11171600

  16. 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.

  17. Perceived Partner Responsiveness Predicts Diurnal Cortisol Profiles 10 Years Later

    PubMed Central

    Slatcher, Richard B.; Selcuk, Emre; Ong, Anthony D.

    2015-01-01

    Several decades of research have demonstrated that marital relationships have a powerful influence on physical health. However, surprisingly little is known about how marriage affects health—both in terms of psychological processes and biological ones. We investigated the associations between perceived partner responsiveness—the extent to which people feel understood, cared for and appreciated by their romantic partner—and diurnal cortisol over a 10-year period in a large sample of married and cohabitating couples in the U.S. Partner responsiveness predicted higher wakeup cortisol values and steeper (“healthier”) cortisol slopes at the 10-year follow-up, and these associations remained strong after controlling for demographic factors, depressive symptoms, agreeableness, and other positive and negative relationship factors. Further, declines in negative affect over the 10-year period mediated the prospective association between responsiveness and cortisol slope. These findings suggest that diurnal cortisol may be a key biological pathway through which social relationships impact long-term health. PMID:26015413

  18. Laser Doppler flowmetry: reproducibility, reliability, and diurnal blood flow variations.

    PubMed

    Roeykens, Herman J J; Deschepper, Ellen; De Moor, Roeland J G

    2016-08-01

    The aim of this investigation was (1) to evaluate the reliability of laser Doppler flowmetry (LDF) taking into consideration the use of a silicone splint and the inclination of the probe towards the buccal surface of a human tooth and (2) to determine whether diurnal variations of pulpal blood flow can be registered by means of LDF. Forty-one splints were made by one and the same principal investigator for the registration of pulpal blood flow in vivo in a maxillary right central incisor. Thirty dentists, without experience in LDF recording, were then asked to drill a right-angled shaft in a pre-manufactured splint with a referral point at 2 mm from the enamel-cement border central on the buccal surface of the right central upper incisor. The remaining 11 splints were handled by the principal investigator. The shafts in the 30 splints were analysed using Cone Beam CT imaging of the axial and sagittal angles and compared these to the 11 shafts prepared by the trained principal investigator. LDF was recorded for 90 s in each splint and statistically analysed. LDF values without the use of a splint were statistically significantly different (p < 0.05) and the variance was greater, indicating the superiority of splint use. Significant diurnal variations on LDF values were observed, indicating that special attention should be paid to registration during the day, especially when multiple measurements are to be compared. PMID:27184153

  19. 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

  20. Diurnal patterns in lightning activity over South America

    NASA Astrophysics Data System (ADS)

    Ávila, Eldo E.; Bürgesser, Rodrigo E.; Castellano, Nesvit E.; Nicora, M. Gabriela

    2015-04-01

    Satellite observations of lightning flash distribution data are used to examine the diurnal cycle of lightning activity over the tropical and subtropical regions of South America. A harmonic analysis is used to study the spatial variations in the peak and strength of diurnal lightning activity across this area. Results show that in the northern and central regions of South America, the times of maxima in lightning activity was concentrated from late afternoon to evening hours (between 14:00 and 18:00 local time), which may be associated with the peaking of the local convective activity connected with heating of the surface caused by daytime insolation. In subtropical South America, particularly in the area limited by 25°S, 35°S of latitude and 70°W, 50°W of longitude, the time of maximum lightning activity was shifted to nocturnal hours, extending from close to midnight to early morning hours. This behavior can be associated to the peak in mesoscale convective systems in the region which occurs in the morning hours. The annual flash densities in the tropical and subtropical parts of the continent were found to have comparable magnitudes. However, the contribution of the continental tropics to the global electric circuit dominates over the continental subtropics contribution throughout all seasons, since the surface covered by the tropical region is more than twice the area covered by the subtropical region.

  1. Diurnal wind variability under heatwaves and extreme drought periods

    NASA Astrophysics Data System (ADS)

    Jiménez, Pedro A.; Vilöguerau de Arellano, Jordi; Fidel González-Rouco, J.; Navarro, Jorge; Montávez, Juan P.; García-Bustamante, Elena; Dudhia, Jimy

    2010-05-01

    Extreme weather situations produce strong impacts on society, infrastructures and ecosystems. The drought and heatwave that affected Europe in the summer of 2003 produced enormous socioeconomic implications. The anticyclonic conditions and a deficit of soil moisture availability led to the extremely high surface air temperatures registered. Several studies have shown that the characteristics of the 2003 European summer will be more frequent, more intense and longer lasting in the future. Therefore, determining atmospheric flow patterns during the heat wave and drought of 2003 is necessary in order to assess potential modifications in the circulations due to associated warmer and drier conditions. However, the effects that the extreme weather situation of the summer of 2003 produced on the surface wind have received little attention. In this work, we examine changes in the wind field due to the heatwave and drought conditions that occurred in Europe during the summer of 2003. Our analysis, based on observations and high resolution mesoscale modelling, shows a 22 % decrease in the wind diurnal cycle for summer 2003 values compared to a climatological series based on the period from 1992-2004. We discuss the wind diurnal variability in terms of the synoptic scale atmospheric conditions, and of the mesoscale and boundary layer dynamic contribution influenced by the lower values in the soil moisture. The results suggest the synoptic conditions as the main reason of the wind field change and that these are modulated by the moisture conditions of the soil.

  2. Adaptations for nocturnal and diurnal vision in the hawkmoth lamina.

    PubMed

    Stöckl, Anna L; Ribi, Willi A; Warrant, Eric J

    2016-01-01

    Animals use vision over a wide range of light intensities, from dim starlight to bright sunshine. For animals active in very dim light the visual system is challenged by several sources of visual noise. Adaptations in the eyes, as well as in the neural circuitry, have evolved to suppress the noise and enhance the visual signal, thereby improving vision in dim light. Among neural adaptations, spatial summation of visual signals from neighboring processing units is suggested to increase the reliability of signal detection and thus visual sensitivity. In insects, the likely neural candidates for carrying out spatial summation are the lamina monopolar cells (LMCs) of the first visual processing area of the insect brain (the lamina). We have classified LMCs in three species of hawkmoths with considerably different activity periods but very similar ecology-the diurnal Macroglossum stellatarum, the nocturnal Deilephila elpenor and the crepuscular-nocturnal Manduca sexta. Using this classification, we investigated the anatomical adaptations of hawkmoth LMCs suited for spatial summation. We found that specific types of LMCs have dendrites extending to significantly more neighboring cartridges in the two nocturnal and crepuscular species than in the diurnal species, making these LMC types strong candidates for spatial summation. Moreover, while the absolute number of cartridges visited by the LMCs differed between the two dim-light species, their dendritic extents were very similar in terms of visual angle, possibly indicating a limiting spatial acuity. The overall size of the lamina neuropil did not correlate with the size of its LMCs. PMID:26100612

  3. Coordinated radar observations of atmospheric diurnal tides in equatorial regions

    NASA Astrophysics Data System (ADS)

    Tsuda, Toshitaka; Ohnishi, Kazunori; Isoda, Fusako; Nakamura, Takuji; Vincent, Robert A.; Reid, Iain M.; Harijono, Sri Woro B.; Sribimawati, Tien; Nuryanto, Agus; Wiryosumarto, Harsono

    1999-07-01

    The long-term behavior of atmospheric tides in the mesosphere and lower thermosphere has been observed with the meteor wind radar (MWR) in Jakarta, Indonesia (6°S, 107°E) from November 1992 to August 1997. The amplitudes and phases of the diurnal tides show systematic seasonal variations, particularly distinct in the meridional component. In addition, substantial interannual variability is evident, characterized by a biennial periodicity of tidal parameters, and considerably small tidal amplitudes exclusively seen in 1996. The MWR results are compared with the Global Scale Wave Model (GSWM) as well as MF radar data collected in two equatorial sites in Pontianak (0.03°N, 109°E) and Christmas Island (2°N, 158°W) for November 1995-July 1997 and January 1996-October 1997, respectively. Comparison studies of these radar data have revealed the detailed latitudinal structure of the diurnal tide near the equator. The GSWM has successfully described the general characteristics of the radar results, although some discrepancies are recognized. In 1996 when radar data are available at all the three sites, the monthly mean values of tidal amplitudes at 90 km agreed very well between Jakarta and Pontianak, while significant discrepancy was found for Christmas Island, suggesting the existence of geographical effects such as non-migrating tides.

  4. Diurnal cycle of convective activity over ocean in the Tropics

    NASA Astrophysics Data System (ADS)

    Hara, Masayuki; Takahashi, Hiroshi; Fujita, Mikiko

    2015-04-01

    In this study, the influence of land mass on the diurnal cycle of convective activity is analyzed. 17-year observation of Tropical Rainfall Measuring Mission (TRMM) 2A25 V7 (1998-2014) Estimated Surface Rain (ESR) is used as a precipitation data. We rasterized the ESR data into 0.1x0.1 degree mesh for each local solar time (LST) of observation. U. S. Geological Survey Global Land Cover Characterization (USGS GLCC) Version 2 data is used for determining the shoreline. As the many studies indicated, the precipitation peak time is about 3 LST over the Tropical ocean near the coastline, and about 15 LST over the Tropical land. Although the total precipitation amount strongly depends on the distance from the shoreline, The phase of the diurnal cycle over the ocean is not dependent on the distance from the nearest shoreline. We also performed a series of ideal experiments with a quasi-three dimensional domain using non-hydrostatic atmospheric model to elucidate the detailed feature of the relationship between land-sea contrast and local convection systems.

  5. Diurnal variations in the human host response to endotoxin.

    PubMed

    Pollmächer, T; Mullington, J; Korth, C; Schreiber, W; Hermann, D; Orth, A; Galanos, C; Holsboer, F

    1996-11-01

    To investigate diurnal variations in the host response to endotoxin, Salmonella abortus equi endotoxin (0.8 ng/kg) was given intravenously to healthy men in a placebo-controlled design at 0900 or 1900 h. The time course of rectal temperature and the plasma levels of tumor necrosis factor- alpha (TNF-alpha), interleukin-6 (IL-6), adrenocorticotropic hormone (ACTH), and cortisol were monitored for 11 h following the injections. The time of day did not affect the endotoxin-induced increase in plasma TNF-alpha or IL-6. However, subjects who received endotoxin in the evening, when endogenous glucocorticoid levels were low, showed about twice the increases in rectal temperature and plasma ACTH and cortisol levels as those who received endotoxin in the morning, when endogenous glucocorticoid levels were high. These results demonstrate diurnal variations in the human susceptibility to endotoxin that may be due to a suppression of the biologic effects of TNF-alpha and IL-6 by endogenous glucocorticoids. PMID:8896506

  6. Asymmetry in the Diurnal Variation of Surface Albedo

    NASA Technical Reports Server (NTRS)

    Mayor, S.; Smith, W. L., Jr.; Nguyen, L.; Alberta, T. A.; Minnis, P.; Whitlock, C. H.; Schuster, G. L.

    1996-01-01

    Remote sensing of surface properties and estimation of clear-sky and surface albedo generally assumes that the albedo depends only on the solar zenith angle. The effects of dew, frost, and precipitation as well as evaporation and wind can lead to some systematic diurnal variability resulting in an asymmetric diurnal cycle of albedo. This paper examines the symmetry of both surface-observed albedos and top-of-the-atmosphere (TOA) albedos derived from satellite data. Broadband and visible surface albedos were measured at the Department of Energy Atmospheric Radiation Measurement (ARM) Program Southern Great Plains Central Facility, at some fields near the ARM site, and over a coniferous forest in eastern Virginia. Surface and wind conditions are available for most cases. GOES-8 satellite radiance data are converted to broadband albedo using bidirectional reflectance functions and an empirical narrowband-to-broadband relationship. The initial results indicate that surface moisture has a significant effect and can change the albedo in the afternoon by 20% relative to its morning counterpart. Such effects may need to be incorporated in mesoscale and even large-scale models of atmospheric processes.

  7. 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. PMID:26316023

  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. 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.

  10. 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. PMID:22134883

  11. 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.

  12. Shiftwork and Diurnal Salivary Cortisol Patterns Among Police Officers

    PubMed Central

    Charles, Luenda E.; Fekedulegn, Desta; Burchfiel, Cecil M.; Hartley, Tara A.; Andrew, Michael E.; Violanti, John M.; Miller, Diane B.

    2016-01-01

    Objective To investigate associations between shiftwork and diurnal salivary cortisol among 319 police officers (77.7% men) Methods Information on shiftwork was obtained from the City of Buffalo, NY electronic payroll records. Saliva was collected using Salivettes at seven time points and analyzed for free cortisol concentrations (nmol/L) using a chemiluminescence immunoassay. Mean slopes and areas under the curve were compared across shift schedule using analysis of variance (ANOVA)/analysis of covariance (ANCOVA). Results Officers working primarily on the night shift had a significantly shallower slope. Mean slope (nmol/L/minutes) of the cortisol curve varied significantly across shifts (day: −0.00332 ± 0.00017, afternoon: −0.00313 ± 0.00018, night: −0.00257 ± 0.0002); adjusted P = 0.023. Conclusions Our results suggest that night shiftwork is a work-place factor that may alter the response of the hypothalamic–pituitary–adrenal (HPA) axis to the circadian cues responsible for the pattern of the diurnal cortisol curve. PMID:27129020

  13. 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.

  14. 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.

  15. Diurnal variation in nutrients and chimpanzee foraging behavior.

    PubMed

    Carlson, Bryce A; Rothman, Jessica M; Mitani, John C

    2013-04-01

    Primate feeding behavior varies over long (e.g., weekly, seasonally, yearly) and short (e.g., hourly) scales of time due to changes in resource availability and the nutritional composition of foods. While the factors that affect long-term changes in feeding behavior have received considerable attention, few data exist regarding what drives variability in feeding behavior over the course of a single day. To address this problem, we investigated diurnal variation in chimpanzee feeding on the leaves of two species of saplings, Pterygota mildbraedii and Celtis africana, at Ngogo, Kibale National Park, Uganda. Specifically, we related short-term changes in chimpanzee feeding behavior on these leaves to diurnal variation in their nutritional composition. Results showed that chimpanzees fed on the leaves of both saplings more in the evening than they did in the morning. The nutritional quality of leaves also improved over the course of the day. Concentrations of cellulose and lignin were lower and total nonstructural carbohydrates (including sugars and starch) were higher in the evening for P. mildbraedii, and sugars were higher in the evening for C. africana. These data suggest that chimpanzees consume these resources when their quality is highest, and consequently, may track the nutrient composition of their foods over very short periods that span only a few hours. In the future, foods collected for analyses must control for time of sampling to ensure biologically meaningful assays of nutrient composition. PMID:23300012

  16. Cumulus moistening, the diurnal cycle, and large-scale tropical dynamics

    NASA Astrophysics Data System (ADS)

    Ruppert, James H., Jr.

    Observations and modeling techniques are employed to diagnose the importance of the diurnal cycle in large-scale tropical climate. In the first part of the study, soundings, radar, and surface flux measurements collected in the Indian Ocean DYNAMO experiment (Dynamics of the Madden--Julian Oscillation, or MJO) are employed to study MJO convective onset. According to these observations, MJO onset takes place as follows: moistening of the low--midtroposphere is accomplished by cumuliform clouds that deepen as the drying by large-scale subsidence and horizontal advection simultaneously wane. This relaxing of subsidence is tied to decreasing column radiative cooling, which links back to the evolving cloud population. A new finding from these observations is the high degree to which the diurnal cycle linked to air-sea and radiative fluxes invigorates clouds and drives column moistening each day. This diurnally modulated cloud field exhibits pronounced mesoscale organization in the form of open cells and horizontal convective rolls. Based on these findings, it is hypothesized that the diurnal cycle and mesoscale cloud organization represent two manners in which local convective processes promote more vigorous day-to-day tropospheric moistening than would otherwise occur. A suite of model tests are carried out in the second part of the study to 1) test the hypothesis that the diurnal cycle drives moistening on longer timescales, and 2) better understand the relative roles of diurnally varying sea surface temperature (SST) and direct atmospheric radiative heating in the diurnal cycle of convection. Moist convection is explicitly represented in the model, the diurnal cycle of SST is prescribed, and cloud-interactive radiation is simulated with a diurnal cycle in shortwave heating. The large-scale dynamics are parameterized using the spectral weak temperature gradient (WTG) technique recently introduced by Herman and Raymond. In this scheme, external (i.e., large

  17. Diurnally Varying Hydrogen Volatiles or Regolith Temperature? Mare and Highlands Studies of the Moon's Diurnally Modulating Epithermal Neutron Flux Using LRO's LEND, Diviner, and LOLA Instruments

    NASA Astrophysics Data System (ADS)

    McClanahan, T. P.; LEND Team; Parsons, A. M.; Williams, J. P.; Mazarico, E.

    2015-10-01

    In this study we seek to discriminate the source of variation that is diurnally modulating the Moon's neutron emission flux. We characterize the neutron emission flux from the topography in the northern mare and highlands regions.

  18. 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

  19. 40 CFR 1045.625 - What requirements apply under the Diurnal Transition Program?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... VESSEL IS EXEMPT FROM DIURNAL STANDARDS UNDER 40 CFR 1045.625.” (d) Notification and reporting. You must...(d) and 40 CFR 1060.105. The provisions of this section do not apply for portable marine fuel tanks... are exempt from the prohibitions in 40 CFR 1068.101(a)(1) with respect to diurnal emissions,...

  20. 40 CFR 1045.625 - What requirements apply under the Diurnal Transition Program?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... VESSEL IS EXEMPT FROM DIURNAL STANDARDS UNDER 40 CFR 1045.625.” (d) Notification and reporting. You must...(d) and 40 CFR 1060.105. The provisions of this section do not apply for portable marine fuel tanks... are exempt from the prohibitions in 40 CFR 1068.101(a)(1) with respect to diurnal emissions,...

  1. The Influence of Diurnal Temperature Variation on Degree-Day Accumulation and Insect Life History

    PubMed Central

    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. PMID:25790195

  2. Diurnal variation of stratospheric and mesospheric ozone observed by ground-based microwave radiometry

    NASA Astrophysics Data System (ADS)

    Hocke, Klemens; Studer, Simone; Kämpfer, Niklaus; Schanz, Ansgar

    2013-04-01

    Knowledge on diurnal ozone variations in the middle atmosphere is of general interest for the estimation of atmospheric tides propagating throughout the whole atmosphere. Another aspect is the important area of ozone trend analysis. Does the ozone layer recover in the next decades? Expected trends are of the order of 1 percent per decade. If the diurnal ozone variation is not considered, avoided, or removed in the observational data sets then an ozone trend detection will be not possible since the amplitude of the diurnal variation of stratospheric ozone is of the same order as the decadal ozone trend. Ground-based microwave radiometry measures the diurnal ozone variation at a certain geographic location at altitudes from 25 to 65 km. Here we discuss the challenges for the measurement technique and the retrieval method. Finally we present characteristics of the diurnal ozone variation above Switzerland, continuously observed since 1994.

  3. Lidar observation campaigns on diurnal variations of the sodium layer in Beijing, China

    NASA Astrophysics Data System (ADS)

    Wang, Jihong

    2016-07-01

    Based on observations from daytime lidars in eastern China, diurnal cycles of the sodium layer over Beijing (40.5°N, 116°E) are investigated. Diurnal variations of Na density, root mean square (RMS) layer width, and centroid height of the sodium layer are analyzed. Results reveal that the large diurnal cycles of the sodium layer are controlled mainly by 24-hr oscillations at the Beijing observation site. The diurnal variation over Beijing was controlled principally by photoionization and photochemistry effects during another campaign, and there was little evidence of direct tidal perturbations. The comparisons suggest that the diurnal variation of the sodium layer perhaps has obvious regional characteristics across China. The variation can be either controlled mainly by tidal perturbations or by photoionization and photochemistry effects in different seasons.

  4. Impact of land-sea breezes at different scales on the diurnal rainfall in Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, Wan-Ru; Wang, Shih-Yu

    2014-10-01

    The formation mechanism of diurnal rainfall in Taiwan is commonly recognized as a result of local forcings involving solar thermal heating and island-scale land-sea breeze (LSB) interacting with orography. This study found that the diurnal variation of the large-scale circulation over the East Asia-Western North Pacific (EAWNP) modulates considerably the diurnal rainfall in Taiwan. It is shown that the interaction between the two LSB systems—the island-scale LSB and the large-scale LSB over EAWNP—facilitates the formation of the early morning rainfall in western Taiwan, afternoon rainfall in central Taiwan, and nighttime rainfall in eastern Taiwan. Moreover, the post-1998 strengthening of a shallow, low-level southerly wind belt along the coast of Southeast China appears to intensify the diurnal rainfall activity in Taiwan. These findings reveal the role of the large-scale LSB and its long-term variation in the modulation of local diurnal rainfall.

  5. Impact of Land-Sea Breezes at Different Scales on the Diurnal Rainfall in Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, Wan-Ru; Wang, Shih-Yu

    2014-05-01

    The formation mechanism of diurnal rainfall in Taiwan is commonly recognized as a result of local forcings involving solar thermal heating and island-scale land-sea breeze (LSB) interacting with orography. This study found that the diurnal variation of the large-scale circulation over the East Asia-Western North Pacific (EAWNP) modulates considerably the diurnal rainfall in Taiwan. It is shown that the interaction between the two LSB systems - the island-scale LSB and the large-scale LSB over EAWNP - facilitates the formation of the early morning rainfall in western Taiwan, afternoon rainfall in central Taiwan, and nighttime rainfall in eastern Taiwan. Moreover, the post-1998 strengthening of a shallow, low-level southerly wind belt along the coast of Southeast China appears to intensify the diurnal rainfall activity in Taiwan. These findings reveal the role of the large-scale LSB and its long-term variation in the modulation of local diurnal rainfall.

  6. 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.

  7. 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.

  8. Measurement of stratospheric HOCl - Concentration profiles, including diurnal variation

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Johnson, D. G.; Traub, W. A.

    1989-01-01

    Determinations have been made of concentration profiles of HOCl in the earth's stratosphere, including the diurnal variation. Measurements of the rotational Q2 branch at 99.5/cm and of five RR(J3) transitions between 143 and 159/cm were made using far-infrared thermal emission spectroscopy. The spectra were obtained during a balloon flight of the FIRS 2 far-infrared Fourier-transform spectrometer and telescope from Palestine, Texas on May 12-13, 1988. From these measurements, altitude profiles of HOCl from 23 to 42 km are obtained. Daytime and nighttime average profiles of HOCl, as well as measurements on a 30-min time scale through the sunset transition at a single (35 km) altitude are presented. The measured profiles are lower than the current predictions from several modeling groups by a factor of approximately 0.6.

  9. Why the Diurnal Pressure Variation at Curiosity is so Large

    NASA Astrophysics Data System (ADS)

    Richardson, M. I.; Heavens, N. G.; Mischna, M. A.; Newman, C. E.; Wilson, R.; Team, M.

    2013-12-01

    The diurnal range of pressure observed by the Curiosity Rover Environmental Monitoring Station (REMS) is larger than that seen at any prior Martian landing site [Harri et al., JGR 2013]. Shortly after landing, the percentage diurnal variation was roughly 11%. This range compares with general circulation model (GCM) predictions at roughly 2-5 degrees resolution of 6-7%. In the GCM, the range is primarily due to the large scale thermal tides and equatorial Kelvin waves. However, the question of why the observed range was so much larger than the GCM-predicted range was the biggest early puzzle of the REMS observation campaign. A significant clue to the puzzle is provided by the fact that high resolution models (~<10 km resolution) can adequately capture the observed range, but that if these models are averaged over an area equivalent to the GCM grid cell size, they also simultaneously match the GCM-predicted ranges. The augmented range in pressure seen by REMS and also by the mesoscale models is thus a process operating on scales smaller than captured by the GCM. Indeed, the Gale Crater site is unique amongst Mars landing sites in the large degree of topographic relief on scales of ~10km. Using basic physical arguments and mesoscale modeling, we show that the augmented range of daily pressure variation measured by REMS is due to a process of hydrostatic adjustment in response to the daily cycle of air temperature. In the presence of a slope, a change in scale height (which depends only on the air temperature) demands a change in the horizontal gradient of surface pressure. Thus, during the warmer portion of the day, the pressure difference between two fixed points at different elevations along a slope will be smaller than that during the cooler portion. If the lower elevation point is held at fixed pressure, the upper point experiences a daily pressure cycle with higher pressure during the warmer daytime and lower during the cooler night. If instead, the domain

  10. 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.

  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. 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

  13. 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

  14. Industrial emissions cause extreme urban ozone diurnal variability

    NASA Astrophysics Data System (ADS)

    Zhang, Renyi; Lei, Wenfang; Tie, Xuexi; Hess, Peter

    2004-04-01

    Simulations with a regional chemical transport model show that anthropogenic emissions of volatile organic compounds and nitrogen oxides (NOx = NO + NO2) lead to a dramatic diurnal variation of surface ozone (O3) in Houston, Texas. During the daytime, photochemical oxidation of volatile organic compounds catalyzed by NOx results in episodes of elevated ambient O3 levels significantly exceeding the National Ambient Air Quality Standard. The O3 production rate in Houston is significantly higher than those found in other cities over the United States. At night, a surface NOx maximum occurs because of continuous NO emission from industrial sources, and, consequently, an extensive urban-scale "hole" of surface ozone (<10 parts per billion by volume in the entire Houston area) is formed as a result of O3 removal by NO. The results suggest that consideration of regulatory control of O3 precursor emissions from the industrial sources is essential to formulate ozone abatement strategies in this region.

  15. 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.

  16. Diurnal emissivity dynamics in bare versus biocrusted sand dunes

    NASA Astrophysics Data System (ADS)

    Rozenstein, O.

    2015-12-01

    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.

  17. 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. PMID:25437760

  18. Spatiotemporal Variation of Diurnal Cycle under the Different MJO Phases

    NASA Astrophysics Data System (ADS)

    Yoneyama, K.

    2013-12-01

    During a two-month special observing period (October - November 2011) of the MJO field campaign, which composed of several projects of CINDY2011, DYNAMO, AMIE, and LASP, two MJO events were captured by the intensive (3-hourly) sounding array deployed over the central Indian Ocean. While the upward moistening was confirmed before the onset of these events, both cases were identified as an MJO event after the cloud systems reached over the central Indian Ocean from the Inter-tropical Convergence Zone in the Southern Hemisphere. While this feature suggests the lateral transport of moist air, dry intrusion into the equatorial region in the lower/mid-troposphere was also observed. The relationship among these features are not well understood. In the previous studies related to the recharge process under the suppressed condition with dry air aloft, diurnal cycle was a key to moisten the dry atmosphere above. Thus, as a first step to understand their relationship as well as a role for the initiation process of the MJO convection over the equatorial region, vertical features obtained by the radiosonde sounding at the southern array were examined with focus of diurnal cycle as a basic variation by referring the MJO phase defined by Wheeler and Hendon's method. Basically, stable layers near 0 C (~550 hPa) and trade inversion (800~750 hPa) became dominant over the equatorial sites after the MJO convective center moved east (Phases 4-7). During the pre-onset and onset period (Phases 2-3), lower troposphere (~970 hPa) became more unstable in nighttime (18-04 LT) and moist air region extended to upward from early morning (03-06 LT, ~700 hPa) to mid-troposphere in daytime (12-18 LT, 500~300 hPa). Stable layers near the trade inversion and 0 C rather appear accompanied with convections (i.e. convection might produce or contribute those stable layers).

  19. Diurnal cycle of the Oklahoma City urban heat island

    NASA Astrophysics Data System (ADS)

    Basara, Jeffrey B.; Hall, Peter K.; Schroeder, Amanda J.; Illston, Bradley G.; Nemunaitis, Kodi L.

    2008-10-01

    Between the dates of 28 June and 31 July 2003, the Joint Urban 2003 (JU2003) field project was conducted in Oklahoma City and was the largest urban dispersion experiment ever in North America. Because the focus of JU2003 was on atmospheric processes within the urban environment, an extremely dense network of instrumentation was deployed in and around the central business district (CBD) both prior to and during the field experiment. Among the variables collected were high-resolution observations of air temperature from various instrument sources. Additional observations of air temperature were also collected at Oklahoma Mesonet stations in the rural areas surrounding Oklahoma City. Using an index value, the diurnal cycle of the urban heat island (UHI) for Oklahoma City, with respect to the surrounding rural terrain, was quantified. The results revealed a consistent mean nocturnal UHI greater than 1.5°C at both 2 and 9 m. However, observations at 2 m during JU2003 revealed a significant urban "cool" island during the convective portion of the day. The mean variability of temperature within the urban core of Oklahoma City increased significantly after sunrise, increased to a maximum near solar noon, and decreased following sunset. These results were inconsistent with the rural observations wherein the variability among sites was maximized during the nocturnal period. Finally, the vertical temperature gradient between 2 and 9 m demonstrated a clear and strong diurnal trend at the rural locations, whereas observations from the urban environment were nearly isothermal and consistent with near-neutral conditions throughout JU2003.

  20. 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.

  1. Diurnal variation of the human adipose transcriptome and the link to metabolic disease

    PubMed Central

    Loboda, Andrey; Kraft, Walter K; Fine, Bernard; Joseph, Jeffrey; Nebozhyn, Michael; Zhang, Chunsheng; He, Yudong; Yang, Xia; Wright, Christopher; Morris, Mark; Chalikonda, Ira; Ferguson, Mark; Emilsson, Valur; Leonardson, Amy; Lamb, John; Dai, Hongyue; Schadt, Eric; Greenberg, Howard E; Lum, Pek Yee

    2009-01-01

    Background Circadian (diurnal) rhythm is an integral part of the physiology of the body; specifically, sleep, feeding behavior and metabolism are tightly linked to the light-dark cycle dictated by earth's rotation. Methods The present study examines the effect of diurnal rhythm on gene expression in the subcutaneous adipose tissue of overweight to mildly obese, healthy individuals. In this well-controlled clinical study, adipose biopsies were taken in the morning, afternoon and evening from individuals in three study arms: treatment with the weight loss drug sibutramine/fasted, placebo/fed and placebo/fasted. Results The results indicated that diurnal rhythm was the most significant driver of gene expression variation in the human adipose tissue, with at least 25% of the genes having had significant changes in their expression levels during the course of the day. The mRNA expression levels of core clock genes at a specific time of day were consistent across multiple subjects on different days in all three arms, indicating robust diurnal regulation irrespective of potential confounding factors. The genes essential for energy metabolism and tissue physiology were part of the diurnal signature. We hypothesize that the diurnal transition of the expression of energy metabolism genes reflects the shift in the adipose tissue from an energy-expending state in the morning to an energy-storing state in the evening. Consistent with this hypothesis, the diurnal transition was delayed by fasting and treatment with sibutramine. Finally, an in silico comparison of the diurnal signature with data from the publicly-available Connectivity Map demonstrated a significant association with transcripts that were repressed by mTOR inhibitors, suggesting a possible link between mTOR signaling, diurnal gene expression and metabolic regulation. Conclusion Diurnal rhythm plays an important role in the physiology and regulation of energy metabolism in the adipose tissue and should be

  2. Diurnal precipitation and high cloud frequency variability over the Gulf Stream and over the Kuroshio

    NASA Astrophysics Data System (ADS)

    Minobe, Shoshiro; Takebayashi, Shogo

    2015-04-01

    Recent studies show mid-latitude western boundary currents (WBCs) substantially influence the atmosphere aloft, and an important feature is enhanced rain band over the WBCs in climatological mean field. However, how such long-term, climate phenomena are related to shorter, weather timescale phenomena are generally remained to be explored. In this paper, diurnal precipitation and cloud variations are investigated global mid-latitude oceans with emphasis on air-sea interactions over WBCs using satellite-derived precipitation and outgoing longwave radiation (OLR) datasets. Strong 24-h period components of precipitations are found over the Gulf Stream in summer and over the Kuroshio in the East China Sea in early summer (Baiu-Meiyu season), respectively. Similar diurnal precipitations are not observed in WBCs in the Southern Hemisphere year around. The diurnal precipitation cycles over the Gulf Stream and the Kuroshio exhibit peak phases in the early to late morning for the Gulf Stream and late morning to early afternoon for the Kuroshio, with southeastward phase propagations. High cloud frequency derived from OLR data exhibit consistent diurnal cycles. A substantial difference of diurnal cycles between the Gulf Stream and the Kuroshio regions are associated with the large-scale Baiu-Meiyu rain and cloud bands for the latter region. Diurnal precipitation and high cloud variability is found in the vicinity of the Kuroshio itself, embedded in the Baiu-Meiyu rain and cloud bands distributing in a wider area without a strong diurnal component. The spatial and seasonal distributions of the diurnal variability over these WBCs strongly suggests that the diurnal precipitation and cloud cycles are essential aspects of deep heating mode of atmospheric response recently reported for these WBCs. These results indicate that these WBCs in the Northern Hemisphere play an important role in modulating short-term precipitation variations, and on the other hand diurnal variability can be

  3. Inferring land surface parameters from the diurnal variability of microwave and infrared temperatures

    NASA Astrophysics Data System (ADS)

    Norouzi, Hamidreza; Temimi, Marouane; AghaKouchak, Amir; Azarderakhsh, Marzieh; Khanbilvardi, Reza; Shields, Gerarda; Tesfagiorgis, Kibrewossen

    This study investigates the properties of the diurnal cycle of microwave brightness temperatures (TB), namely the phase and the amplitude, and their variability in time and space over the globe to infer information on key land surface parameters like changes in soil texture spatial distribution, soil moisture conditions, and vegetation density. The phase corresponds to the lag between Land Surface Temperature (LST) and TB diurnal cycles. The amplitude is determined as the difference between the maximum and the minimum of TB diurnal cycle. The diurnal cycle of TB was constructed using observations from the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) and the Special Sensor Microwave/Imager (SSM/I). The latter offer a series of sensors, namely, F13, F14, and F15 that were used in this study for a higher temporal coverage and more accurate diurnal cycle determination. LST estimates, which are available every 3 h from the International Satellite Cloud Climatology Project (ISCCP) database were used to build the LST diurnal cycle. ISCCP LST data is an infrared-based temperature with almost no penetration and is the representative of top skin temperature. The analyses of the diurnal cycles showed that the diurnal amplitude of TB decreases as the vegetation density increases, especially in the case of low frequencies which penetrate deeper into the canopy which makes them more sensitive to changes in vegetation density. The interannual variations of TB diurnal amplitudes were also in agreement with the seasonality of the vegetation cover. Over desert and rain forest regions where surface conditions do not vary significantly throughout the year, the changes in diurnal amplitudes were the lowest. A relationship between phase and amplitude values was established. It was found that the amplitude of TB diurnal cycle decreases when the phase lag increases. The spatial distribution of the determined diurnal properties, namely, phase and amplitude of TB

  4. 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.

  5. Satellite, climatological, and theoretical inputs for modeling of the diurnal cycle of fire emissions

    NASA Astrophysics Data System (ADS)

    Hyer, E. J.; Reid, J. S.; Schmidt, C. C.; Giglio, L.; Prins, E.

    2009-12-01

    The diurnal cycle of fire activity is crucial for accurate simulation of atmospheric effects of fire emissions, especially at finer spatial and temporal scales. Estimating diurnal variability in emissions is also a critical problem for construction of emissions estimates from multiple sensors with variable coverage patterns. An optimal diurnal emissions estimate will use as much information as possible from satellite fire observations, compensate known biases in those observations, and use detailed theoretical models of the diurnal cycle to fill in missing information. As part of ongoing improvements to the Fire Location and Monitoring of Burning Emissions (FLAMBE) fire monitoring system, we evaluated several different methods of integrating observations with different temporal sampling. We used geostationary fire detections from WF_ABBA, fire detection data from MODIS, empirical diurnal cycles from TRMM, and simple theoretical diurnal curves based on surface heating. Our experiments integrated these data in different combinations to estimate the diurnal cycles of emissions for each location and time. Hourly emissions estimates derived using these methods were tested using an aerosol transport model. We present results of this comparison, and discuss the implications of our results for the broader problem of multi-sensor data fusion in fire emissions modeling.

  6. 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. PMID:21404852

  7. 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.

  8. The Efficacy of a Transurethral Incision for Diurnal and Nocturnal Enuresis in Young Males

    PubMed Central

    Tobu, Shohei; Noguchi, Mitsuru; Takahara, Kohei; Ichibagase, Yuka; Ikoma, Saya; Udo, Kazuma; Nanri, Maki; Uozumi, Jiro

    2016-01-01

    Introduction In this study, we investigated the effects of treatment with a transurethral incision (TUI) for congenital urethral stenosis, which was accompanied by diurnal and nocturnal enuresis. Methods We recruited 21 young males who presented to our department for the treatment of diurnal and nocturnal enuresis from January 2010 to March 2014. All patients underwent TUI due to urethral stricture found by a close investigation. We surveyed each case to evaluate the improvement of diurnal and/or nocturnal enuresis after TUI. Results One and a half years after TUI, an improvement in diurnal enuresis was observed in 17 of 21 cases (80.9%), whereas that of nocturnal enuresis was observe in only 7 of 21 cases (33.3%), showing the significant contribution of TUI to the improvement of diurnal enuresis (p = 0.001). In the case of diurnal enuresis, continual improvement was observed more than a year after surgery, whereas no improvement was observed in nocturnal enuresis at more than 6 months after surgery. Conclusion TUI is more effective for diurnal enuresis than nocturnal enuresis. At postoperative 6 months, clinicians should thus consider other etiologies for unresponsive cases and start other treatment options. PMID:27390580

  9. Regional Climate Simulations of Summer Diurnal Rainfall Variations over East Asia and Southeast China

    NASA Astrophysics Data System (ADS)

    Huang, W.-R.; Chan, J. C. L.

    2012-04-01

    This study evaluates the simulations of summer (June-August) precipitation over East Asia by the Regional Climate Model Version 3 (RegCM3), with emphasis on the diurnal variations of precipitation over Southeast China (PSEC) during the 1998-2002 summer seasons. The evaluation focuses on the maintenance mechanisms of the diurnal variations in PSEC as proposed by previous observational studies. It is found that the diurnal variations of PSEC are sensitive to the choice of cumulus parameterization schemes (CPSs). In particular, the Grell scheme with the Frisch-Chappell convective closure assumption (GFC) produces reasonable diurnal variations of PSEC. Other CPSs such as the Emanuel scheme produces a weaker late-afternoon maximum of PSEC, and the Kuo scheme as well as the Grell scheme with the Arakawa-Schubert closure assumption (GAS) is unable to simulate the occurrence of the late-afternoon maximum of PSEC. The simulations show that the adoption of the GFC scheme reproduces the large-scale land-sea breeze circulation and the moisture flux convergence that have been documented by previous studies as the maintenance mechanisms of the diurnal variations of PSEC. This feature illustrates the importance of convective cloud feedback at the diurnal timescale in maintaining the large-scale circulation. Furthermore, when the simulation domain covers the entire Tibetan Plateau, the diurnal variations of precipitation over East Asia are found to exhibit a noticeable improvement without changes in the physics schemes.

  10. 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

  11. 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. PMID:18346077

  12. 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

  13. Long-term consistency of diurnal-type preferences among men.

    PubMed

    Broms, Ulla; Pitkäniemi, Janne; Bäckmand, Heli; Heikkilä, Kauko; Koskenvuo, Markku; Peltonen, Markku; Sarna, Seppo; Vartiainen, Erkki; Kaprio, Jaakko; Partonen, Timo

    2014-03-01

    Diurnal type (chronotype) differentiates individuals on an axis between the extremes of evening type to morning type. These diurnal-type preferences are thought to be relatively stable, but follow-up studies are sparse. The study aims were (1) to compare cross-sectional studies of diurnal type preferences between two decades and (2) to analyze the consistency of diurnal-type preferences using a longitudinal dataset. We analyzed a total of 18,087 adult males from four datasets with information on diurnal type and age. Of these, 2144 were available for survival analysis and 567 for analysis of longitudinal diurnal consistency. Diurnal type was assessed by asking the individual to what extent they would rate themselves a morning or an evening person, categorized into four groups. Statistical tests for stability of diurnal type were based on transition matrices and p values obtained using likelihood ratios. Cox regression was used to calculate the relative risk of all-cause mortality in each of the four diurnal type groups. After direct age standardization, 9.5% (95% CI: 9.0-10.1%) of participants in the four datasets were evening types. The cross-sectional data yielded that morning types were less common in the 2000s than two decades earlier. The longitudinal dataset revealed a significant shift from evening type to another type from 1985 to 2008 (p = 0.002). The relative risk of all-cause mortality was 1.3-fold (95% CI: 1.0-1.6; p = 0.05) higher for evening types compared to morning types. At the population level, eveningness appears to have become more prevalent over recent decades. However, on the individual level, the more morningness the chronotype, the more persistent it remains with aging. PMID:24131152

  14. 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

  15. Influence of entrainment and countergradient on the ABL diurnal development

    NASA Astrophysics Data System (ADS)

    Hernández-Ceballos, M. A.

    2009-09-01

    The representation of the diurnal evolution of the boundary layer (ABL) by NCAR-Penn State Mesoscale Model (MM5) and by the mesoscale model Weather Research Forecast (WRF) is compared. Special attention is paid to determine the role of processes that occur near and below the inversion zone: the positive correlation between the heat flux and the gradient (countergradient) and the role of entrainment of heat originating from the free troposphere. Both processes play a key role in the modelling of the diurnal variability of temperature, moisture and atmospheric compounds. A number of 13 simulations are carried out to determine the sensitivity of the model results to the formulation of the ABL height and countergradient heat flux in the Medium Range Forecast (MRF) ABL scheme. Model results are compared with experimental data obtained from the DOMINO (Diel Oxidant Mechanisms in relation to Nitrogen oxides) campaign. It was organized by Max Planck Institute for Atmospheric Chemistry (Germany) in collaboration with the National Institute for Aerospace Technology (Spain). The DOMINO campaign took place at the "Atmospheric Sounding Station - El Arenosillo", a platform dedicated to atmospheric measurements in the Southwest of Spain. All numerical experiments are grouped in four clusters, each focussing on the sensitivity of different relevant aspects. The following aspects of the formulation are analyzed: surface moisture availability (M), the countergradient term (γc) and the ABL height (h). This is done by modifying both the bulk critical Richardson number (Ric) at the inversion zone, and a coefficient of proportionality (b) that determines the excess temperature and countergradient. The importance of b is due to its direct relation in the definition of both, γc and h. The results got with MM5 model show that temperature and specific moisture temporal evolution is not very sensitive to changes in the soil moisture availability (M value from 0.6 to 0.1). Using the MRF

  16. Diurnal changes in the hematological indices in the blood of racing Arabian horses.

    PubMed

    Gill, J; Rastawicka, M

    1986-01-01

    In 8 stallions and 6 mares of pure Arabian horses the diurnal changes in the number and certain parameters of red and white blood cells were studied. All of them showed distinct diurnal changes but they did not fulfill the conditions of circadian rhythm according to Halberg. It was found that most of peaks occurred during the dark phase of 24 hr period except the percentage of eosinophils, erythrocyte diameters and cell rate sedimentation. The majority of indices studied showed the higher mean diurnal levels in the mares than in the stallions. PMID:3606980

  17. Diurnal changes in the metabolic indices in the blood of racing Arabian horses.

    PubMed

    Gill, J; Cedro, H; Piróg, B

    1984-01-01

    In 8 stallions and 6 mares of pure Arabian breed the diurnal changes in the levels of lactic and pyruvic acid, glucose, and alkaline reserve were studied. All of them showed distinct diurnal changes but they failed to fulfil the criteria of circadian rhythm according to Halberg. It was found that all peaks occurred during the dark phase of the 24 h period except the glucose level in the stallions. Three of the indices studied showed higher mean diurnal levels in the mares than in the stallions. Only in the glucose level the mean values were reversed. PMID:6543601

  18. Spatial patterns in timing of the diurnal temperature cycle

    NASA Astrophysics Data System (ADS)

    Holmes, T. R. H.; Crow, W. T.; Hain, C.

    2013-05-01

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from choice of measuring device or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of low Earth orbiting satellites given record lengths of at least three months. Based on a year of data, the spatial patterns of mean DTC timing are compared between Ka-band temperature estimates, geostationary thermal infrared (TIR) temperature estimates and numerical weather prediction model output from the Global Modeling and Assimilation Office (GMAO). It is found that the spatial patterns can be explained by vegetation effects, sensing depth differences and more speculatively the orientation of orographic relief features. In absolute terms, the GMAO model puts the peak of the DTC on average at 12:50 local solar time, 23 min before TIR with a peak temperature at 13:13. Since TIR is the shallowest observation of the land surface, this small difference represents a structural error that possibly affects the models ability to assimilate observations that are closely tied to the DTC. For non-desert areas, the Ka-band observations have only a small delay of about 15 min with the TIR observations which is in agreement with their respective theoretical sensing depth. The results of this comparison provide insights into the structural differences between temperature measurements and models, and can be used as a first step to account for these differences in a coherent way.

  19. Modeling diurnal hormone profiles by hierarchical state space models.

    PubMed

    Liu, Ziyue; Guo, Wensheng

    2015-10-30

    Adrenocorticotropic hormone (ACTH) diurnal patterns contain both smooth circadian rhythms and pulsatile activities. How to evaluate and compare them between different groups is a challenging statistical task. In particular, we are interested in testing (1) whether the smooth ACTH circadian rhythms in chronic fatigue syndrome and fibromyalgia patients differ from those in healthy controls and (2) whether the patterns of pulsatile activities are different. In this paper, a hierarchical state space model is proposed to extract these signals from noisy observations. The smooth circadian rhythms shared by a group of subjects are modeled by periodic smoothing splines. The subject level pulsatile activities are modeled by autoregressive processes. A functional random effect is adopted at the pair level to account for the matched pair design. Parameters are estimated by maximizing the marginal likelihood. Signals are extracted as posterior means. Computationally efficient Kalman filter algorithms are adopted for implementation. Application of the proposed model reveals that the smooth circadian rhythms are similar in the two groups but the pulsatile activities in patients are weaker than those in the healthy controls. PMID:26152819

  20. Diurnal variation of pulmonary artery pressure in chronic heart failure.

    PubMed Central

    Gibbs, J S; Cunningham, D; Shapiro, L M; Park, A; Poole-Wilson, P A; Fox, K M

    1989-01-01

    Variation in pulmonary artery pressure has important consequences for the interpretation of isolated pressure measurements in patients with chronic heart failure. To investigate the nature of diurnal variation in pulmonary artery pressure in chronic heart failure, eight angina-free men (aged 50-72 years) with treated chronic heart failure caused by ischaemic heart disease underwent continuous ambulatory pulmonary artery pressure recording by a transducer tipped catheter. The mean (1 SD) daytime pulmonary artery pressure was 29.6 (5.0) mm Hg systolic and 13.7 (5.6) mm Hg diastolic. The mean change in pressure from day to night was +5.1 (3.2) mm Hg systolic and +3.8 (1.7) mm Hg diastolic; and the mean change from standing to lying +9.3 (2.3) mm Hg systolic and +6.4 (2.1) mm Hg diastolic. In six of the eight patients there was considerable rise in pulmonary artery pressure at night, but in the two patients with the most severe symptoms there was no nocturnal rise. In patients with chronic heart failure, nocturnal pulmonary artery pressure is not determined by postural change alone. But interpretation of isolated pulmonary artery pressure measurements must take the posture of the patient into account. PMID:2757872

  1. Diurnal characteristics of field line resonances at College, Alaska

    SciTech Connect

    Olson, J.V. )

    1987-08-01

    Magnetic variations measured at College, Alaska (L = 5.6), contain a low-amplitude, intermittent tone near 5 mHz. The tone shows a regular variation in frequency throughout the day with the shortest periods (highest frequencies) near local noon and the longest periods (lowest frequencies) in the midnight sector. The wave train is composed of a superposition of individual packets which are not phase coherent. The polarization states of the pulses tend to be left hand, elliptical in the prenoon sector, becoming nearly linear in the afternoon-evening sector with the H component dominant. The short duration of individual packets and the lack of phase coherence imply that these pulsations are not the result of driven resonance but rather are the transient oscillations of the local field line which occur when there is an impulsive change in magnetospheric parameters. Since both field and plasma conditions change on the local field line throughout the day, the natural response frequency of the field line will change as well. The level of diurnal variation is consistent with that calculated by Singer et al. (1981) using realistic field geometries.

  2. Diurnal changes of earthquake activity and geomagnetic Sq-variations

    NASA Astrophysics Data System (ADS)

    Duma, G.; Ruzhin, Y.

    Statistic analyses demonstrate that the probability of earthquake occurrence in many earthquake regions strongly depends on the time of day, that is on Local Time (e.g. Conrad, 1909, 1932; Shimshoni, 1971; Duma, 1997; Duma and Vilardo, 1998). This also applies to strong earthquake activity. Moreover, recent observations reveal an involvement of the regular diurnal variations of the Earth's magnetic field, commonly known as Sq-variations, in this geodynamic process of changing earthquake activity with the time of day (Duma, 1996, 1999). In the article it is attempted to quantify the forces which result from the interaction between the induced Sq-variation currents in the Earth's lithosphere and the regional Earth's magnetic field, in order to assess the influence on the tectonic stress field and on seismic activity. A reliable model is obtained, which indicates a high energy involved in this process. The effect of Sq-induction is compared with the results of the large scale electromagnetic experiment "Khibiny" (Velikhov, 1989), where a giant artificial current loop was activated in the Barents Sea.

  3. Diurnal variation of the global electric circuit from clustered thunderstorms

    NASA Astrophysics Data System (ADS)

    Hutchins, Michael L.; Holzworth, Robert H.; Brundell, James B.

    2014-01-01

    The diurnal variation of the global electric circuit is investigated using the World Wide Lightning Location Network (WWLLN), which has been shown to identify nearly all thunderstorms (using WWLLN data from 2005). To create an estimate of global electric circuit activity, a clustering algorithm is applied to the WWLLN data set to identify global thunderstorms from 2010 to 2013. Annual, seasonal, and regional thunderstorm activity is investigated in this new WWLLN thunderstorm data set in order to estimate the source behavior of the global electric circuit. Through the clustering algorithm, the total number of active thunderstorms are counted every 30 min creating a measure of the global electric circuit source function. The thunderstorm clusters are compared to precipitation radar data from the Tropical Rainfall Measurement Mission satellite and with case studies of thunderstorm evolution. The clustering algorithm reveals an average of 660±70 thunderstorms active at any given time with a peak-to-peak variation of 36%. The highest number of thunderstorms occurs in November (720±90), and the lowest number occurs in January (610±80). Thunderstorm cluster and electrified storm cloud activity are combined with thunderstorm overflight current measurements to estimate the global electric circuit thunderstorm contribution current to be 1090±70 A with a variation of 24%. By utilizing the global coverage and high time resolution of WWLLN, the total active thunderstorm count and current is shown to be less than previous estimates based on compiled climatologies.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

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

    PubMed Central

    Briga, Michael; Verhulst, Simon

    2015-01-01

    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. PMID:26563993

  9. 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.

  10. Variability in diurnal testosterone, exposure to violence, and antisocial behavior in young adolescents.

    PubMed

    Peckins, Melissa K; Susman, Elizabeth J

    2015-11-01

    The purpose of this report is to provide evidence of an association between within-person variability in diurnal testosterone over 1 year, lifetime exposure to violence, and the manifestation of antisocial behavior in 135 pubertal-aged adolescents across 1 year. Adolescents' sex and lifetime history of violence exposure moderated the association between within-person variability in diurnal testosterone and antisocial behavior. Furthermore, sex-stratified analyses revealed that lifetime history of exposure to violence moderated the association between within-person variability in diurnal testosterone and antisocial behavior in females only. This report is unique in that it illuminates sex differences in within-person associations among exposure to violence, individual variability in diurnal testosterone, and antisocial behavior. PMID:26439079

  11. Impacts of the diurnal cycle of solar radiation on spiral rainbands

    NASA Astrophysics Data System (ADS)

    Zhou, Shunwu; Ma, Yue; Ge, Xuyang

    2016-09-01

    Based on idealized numerical simulations, the impacts of the diurnal cycle of solar radiation on the diurnal variation of outer rainbands in a tropical cyclone are examined. It is found that cold pools associated with precipitation-driven downdrafts are essential for the growth and propagation of spiral rainbands. The downdrafts result in surface outflows, which act as a lifting mechanism to trigger the convection cell along the leading edge of the cold pools. The diurnal cycle of solar radiation may modulate the diurnal behavior of the spiral rainbands. In the daytime, shortwave radiation will suppress the outer convection and thus weaken the cold pools. Meanwhile, the limited cold pool activity leads to a strong modification of the moisture field, which in turn inhibits further convection development.

  12. Quasi-Biennial Oscillation signatures in the diurnal tidal winds over Cachoeira Paulista

    NASA Astrophysics Data System (ADS)

    Rodrigues de Araujo, Luciana; Jacobi, Christoph; Batista, Paulo; Lima, Lourivaldo

    2016-07-01

    The solar diurnal tidal plays an important role in the Mesosphere and Lower Thermosphere (MLT) region at low latitudes, in which its amplitude for horizontal winds maximizes around 20 degrees. The tides are excited in the lower atmosphere and stratosphere and can be affected by short and long-term local variations during their upward propagation. In this work, the meteor winds obtained over Cachoeira Paulista (22.7° S, 45.0° W), Brazil, have been used to investigate interannual variability in the amplitude of the diurnal tidal winds. The monthly diurnal tidal displays year to year variations. Amplitudes are strongest when the equatorial quasi-biennial oscillation (QBO) at the 30 mb level is eastward. This behavior can be observed in all seasons in the meridional component, whilst it is more clearly expressed during austral autumn in the zonal component, just when the diurnal tidal is strongest at this latitude.

  13. 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.

  14. 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.

  15. [Model of control of diurnal melatonin secretion by the solar radiation].

    PubMed

    Leonidov, A V

    2014-01-01

    The mathematical model of the control process of diurnal melatonin secretion under the influence of solar radiation on retina photoreceptors is proposed. Invariant relations for calculating melatonin secretion rate and its concentration in blood plasma are obtained. Spectral, time and energy characteristics of solar radiation synchronizing diurnal melatonin secretion and circadian rhythms in human are defined. A possibility of using the relations obtained is shown for arbitrary combination of calendar dates, local time of any time zone and geographical coordinates of a calculated point on earth surface. The adequacy of model is confirmed by coincidence of the calculation data with the results of independent experimental studies on diurnal secretion of melatonin and circadian rhythm in human. The model proposed can be used during investigation of diurnal secretion of melatonin and circadian rhythm in human. PMID:25707251

  16. 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.

  17. 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

  18. Medical Devices; Ophthalmic Devices; Classification of the Diurnal Pattern Recorder System. Final order.

    PubMed

    2016-05-31

    The Food and Drug Administration (FDA) is classifying the diurnal pattern recorder system into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the diurnal pattern recorder system's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. PMID:27236873

  19. 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.

  20. Diurnal heating and cloudiness in the NCAR Community Climate Model (CCM2)

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.; Leovy, Conway B.; Boville, Byron A.; Briegleb, Bruce P.

    1994-01-01

    In this paper, the authors assess the suitability of the heating fileds in the latest version of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM2) for modeling the thermal forcing of atmospheric tides. Accordingly, diurnal variations of the surface pressure, outgoing longwave radiation (OLR), cloudiness, and precipitation are examined in the CCM2. The fields of radiative, sensible, and latent heating are similarly analyzed. These results are subjectively compared with available data. Equatorial diurnal surface pressure tides are fairly well simulated by CCM2. The model successfully reproduces the semidiurnal surface pressure tides; however, this may result in part from reflection of wave energy at the upper boundary. The CCM2 large-scale diurnal OLR is generally consistent with observations. The moist-convective scheme in the model is able to reproduce the diurnally varying cloudiness and precipitation patterns associated with land-sea contrasts; however, the amplitudes of CCM2 diurnal continental convective cloudiness are weaker than observations. The CCM2 boundary-layer sensible heating is consistent with a very limited set of observations, and with estimates obtained from simple models of diffusive heating. Although the CCM2 tropospheric solar radiative heating is similar in magnitude to previous estimates, there are substantial differences in the vertical structures. A definitive assessment of the validity of the CCM2 diurnal cycle is precluded by the lack of detailed observations and the limitations of our CCM2 sample. Nevertheless, the authors conclude that the global-scale components of the CCM2 diurnal heating are useful proxies for the true diurnal forcing of the tides.

  1. Diurnal Variability of Tropical Rainfall Retrieved from Combined GOES and TRMM Satellite Information.

    NASA Astrophysics Data System (ADS)

    Sorooshian, S.; Gao, X.; Hsu, K.; Maddox, R. A.; Hong, Y.; Gupta, H. V.; Imam, B.

    2002-05-01

    Recent progress in satellite remote-sensing techniques for precipitation estimation, along with more accurate tropical rainfall measurements from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and precipitation radar (PR) instruments, have made it possible to monitor tropical rainfall diurnal patterns and their intensities from satellite information. One year (August 1998-July 1999) of tropical rainfall estimates from the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) system were used to produce monthly means of rainfall diurnal cycles at hourly and 1° × 1° scales over a domain (30°S-30°N, 80°E-10°W) from the Americas across the Pacific Ocean to Australia and eastern Asia.The results demonstrate pronounced diurnal variability of tropical rainfall intensity at synoptic and regional scales. Seasonal signals of diurnal rainfall are presented over the large domain of the tropical Pacific Ocean, especially over the ITCZ and South Pacific convergence zone (SPCZ) and neighboring continents. The regional patterns of tropical rainfall diurnal cycles are specified in the Amazon, Mexico, the Caribbean Sea, Calcutta, Bay of Bengal, Malaysia, and northern Australia. Limited validations for the results include comparisons of 1) the PERSIANN-derived diurnal cycle of rainfall at Rondonia, Brazil, with that derived from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) radar data; 2) the PERSIANN diurnal cycle of rainfall over the western Pacific Ocean with that derived from the data of the optical rain gauges mounted on the TOGA-moored buoys; and 3) the monthly accumulations of rainfall samples from the orbital TMI and PR surface rainfall with the accumulations of concurrent PERSIANN estimates. These comparisons indicate that the PERSIANN-derived diurnal patterns at the selected resolutions produce estimates that are similar in magnitude and phase.

  2. Diurnal cortisol rhythm is associated with increased risky decision-making in older adults.

    PubMed

    Weller, Joshua A; Buchanan, Tony W; Shackleford, Crystal; Morganstern, Arielle; Hartman, Joshua J; Yuska, Jonathan; Denburg, Natalie L

    2014-06-01

    Although past research has suggested a link between chronic stress and both physical and mental well-being in older adults, less is known about the degree to which neuroendocrine markers of stress are associated with higher-order cognitive processes such as decision-making. In a sample of healthy older adults (55-85 years), we tested the degree to which variation in the diurnal cortisol rhythm, an index of hypothalamic-adrenal-pituitary axis dynamics, was related to differences in risky decision-making. We found that diurnal cortisol fall predicted performance on the Cups Task, a risky decision-making task that independently tests risk-taking to achieve gains and risk-taking to avoid losses. For potential gains, we found that greater risk-taking was associated with lower diurnal cortisol fall, independent of age or sex of the participant. For risks to avoid potential losses, we found that lower diurnal fall was associated with suboptimal decision-making for men only. Compared with males with more typical diurnal fall, those who displayed lower diurnal fall made more risky choices and demonstrated lower sensitivity to the expected value of the risky choice. We integrate these results with the extant literature on the effects of stress on decision-making and cognitive aging. PMID:24955995

  3. Changes in the diurnal cycles of precipitation over eastern China in the past 40 years

    NASA Astrophysics Data System (ADS)

    Yuan, Weihua; Yu, Rucong; Li, Jian

    2013-03-01

    This study analyzed the interdecadal changes in the diurnal variability of summer (June-August) precipitation over eastern China during the period 1966-2005 using hourly station rain gauge data. The results revealed that rainfall diurnal variations experienced significant interdecadal changes. Over the area to the south of the Yangtze River, as well as the area between the Yangtze and Yellow Rivers, the percentages of morning rainfall (0000-1200 LST) to total rainfall in terms of amount, frequency and intensity, all exhibited increasing interdecadal trends. On the contrary, over North China, decreasing trends were found. As a result, diurnal rainfall peaks also presented pronounced interdecadal variations. Over the area between the Yangtze and Yellow Rivers, there were 16 out of 46 stations with afternoon (1200-0000 LST) frequency peaks in the first 20 years of the 40-year period of study, while only eight remained in the latter 20 years. In North China, seven stations experienced the opposite changes, which accounted for about 21% of the total number of stations. The possible causes for the interdecadal changes in diurnal features were discussed. As the rainfall in the active monsoon period presents morning diurnal peaks, with afternoon peaks in the break period, the decrease (increase) of rainfall in the active monsoon period over North China (the area south of the Yangtze River and the area between the Yangtze and Yellow Rivers) may contribute to interdecadal changes in diurnal rainfall variability.

  4. Diurnal variation in soil respiration under different land uses on Taihang Mountain, North China

    NASA Astrophysics Data System (ADS)

    Liu, Xiuping; Zhang, Wanjun; Zhang, Bin; Yang, Qihong; Chang, Jianguo; Hou, Ke

    2016-01-01

    The aim of this paper is to evaluate the diurnal variation in soil respiration under different land use types on Taihang Mountain, North China, and to understand its response to environmental factors (e.g., soil temperature and moisture) and forest management. Diurnal variations in soil respiration from plantations (Robinia pseudoacacia, Punica granatum, and Ziziphus jujuba), naturally regenerated forests (Vitex negundo var. heterophylla), grasslands (Bothriochloa ischaemum), and farmlands (winter wheat/summer maize) were measured using an LI-8100 automated soil CO2 flux system from May 2012 to April 2013. The results indicated that land use type had a significant effect on the diurnal variation of soil respiration. The diurnal soil respiration from farmlands was highest, followed by Ziziphus jujube, R. pseudoacacia, P. granatum, the lower soil CO2 efflux was found from B. ischaemum and V. negundo var. heterophylla. The diurnal soil respiration across different land use types was significantly affected by soil temperature and moisture, and their interaction. Precipitation-stimulated soil respiration increased more in soil with low water content and less in soil with high water content. The lower diurnal soil respiration from naturally regenerated forests suggests that naturally regenerated vegetation is the optimal vegetation type for reducing global warming.

  5. Assessment of downscaled current and future projections of diurnal rainfall patterns for the Himalaya

    NASA Astrophysics Data System (ADS)

    Bhatt, B. C.; Sobolowski, Stefan; King, Martin P.

    2014-11-01

    In this study we investigate the diurnal precipitation cycle in high-resolution regional climate simulations for present (2000-2010) and future time periods (2030-2040 and 2040-2050) over subregions of the Himalayas. The future periods are simulated under a high-emission scenario, Representative Concentration Pathway 8.5 (RCP8.5) in order to maximize any projected externally driven precipitation signal. For present climate, 4-hourly simulated precipitation is first evaluated against observations to establish model credibility. The diurnal cycle, which is typically characterized by a bimodal structure with primary (secondary) maxima in nighttime (afternoon), is reasonably well represented in the present, giving us confidence when assessing potential future changes. The timing of the precipitation maxima and minima is found to match the observed timings well in the diurnal cycle. In general, the Weather Research and Forecasting model captures the principal shape of the diurnal cycle observed over all the subregions. Under projected future conditions, no significant changes in the diurnal cycle occur. The results suggest modest changes in diurnal precipitation under RCP8.5 emission scenario, as evidenced by an increase in afternoon precipitation around the Himalayas. Although the projected future changes of precipitation presented in this article are within of the expected range of precipitation changes caution must be exercised when interpreting single-model experiments.

  6. 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. PMID:23656875

  7. 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.

  8. Spatial patterns in timing of the diurnal temperature cycle

    NASA Astrophysics Data System (ADS)

    Holmes, T. R. H.; Crow, W. T.; Hain, C.

    2013-10-01

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from choice of measuring device or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of low Earth-orbiting satellites given record lengths of at least three months. Based on a year of data, the spatial patterns of mean DTC timing are compared between temperature estimates from microwave Ka-band, geostationary thermal infrared (TIR), and numerical weather prediction model output from the Global Modeling and Assimilation Office (GMAO). It is found that the spatial patterns can be explained by vegetation effects, sensing depth differences and more speculatively the orientation of orographic relief features. In absolute terms, the GMAO model puts the peak of the DTC on average at 12:50 local solar time, 23 min before TIR with a peak temperature at 13:13 (both averaged over Africa and Europe). Since TIR is the shallowest observation of the land surface, this small difference represents a structural error that possibly affects the model's ability to assimilate observations that are closely tied to the DTC. The equivalent average timing for Ka-band is 13:44, which is influenced by the effect of increased sensing depth in desert areas. For non-desert areas, the Ka-band observations lag the TIR observations by only 15 min, which is in agreement with their respective theoretical sensing depth. The results of this comparison provide insights into the structural differences between temperature measurements and models, and can be used as a first step to account for these differences in a coherent way.

  9. 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. PMID:26045331

  10. Solar cycle and diurnal dependence of auroral structures

    NASA Astrophysics Data System (ADS)

    Partamies, N.; Whiter, D.; Syrjäsuo, M.; Kauristie, K.

    2014-10-01

    In order to facilitate usage of optical data in space climate studies, we have developed an automated algorithm to quantify the complexity of auroral structures as they appear in ground-based all-sky images. The image analysis is based on a computationally determined "arciness" value, which describes how arc like the auroral structures in the image are. With this new automatic method we have analyzed the type of aurora in about 1 million images of green aurora (λ = 557.7nm) captured at five camera stations in Finnish and Swedish Lapland in 1996-2007. We found that highly arc like structures can be observed in any time sector and their portion of the auroral structures varies much less than the fraction of more complex forms. The diurnal distribution of arciness is in agreement with an earlier study with high arc occurrence rate in the evening hours and steadily decreasing toward the late morning hours. The evolution of less arc-like auroral structures is more dependent on the level of geomagnetic activity and solar cycle than the occurrence of arcs. The median arciness is higher during the years close to the solar minimum than during the rest of the solar cycle. Unlike earlier proposed, the occurrence rate of both arcs and more complex auroral structures increases toward the solar maximum and decreases toward the solar minimum. The cyclic behavior of auroral structures seen in our data is much more systematic and clear than previously reported visual studies suggest. The continuous arciness index describing the complexity of auroral structures can improve our understanding on auroral morphology beyond the few commonly accepted structure classes, such as arcs, patches, and omega bands. Arciness can further be used to study the relationship of auroral structures at different complexity levels and magnetospheric dynamics.

  11. 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

  12. 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

  13. 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.

  14. Diurnal temperature range over Europe between 1950 and 2005

    NASA Astrophysics Data System (ADS)

    Makowski, K.; Wild, M.; Ohmura, A.

    2008-04-01

    It has been widely accepted that diurnal temperature range (DTR) decreased on a global scale during the second half of the twentieth century. Here we show however, that the long-term trend of annual DTR has reversed from a decrease to an increase during the 1970s in Western Europe and during the 1980s in Eastern Europe. The analysis is based on the high-quality dataset of the European Climate Assessment and Dataset Project, from which we selected approximately 200 stations, covering the area from Iceland to Algeria and from Turkey to Russia for 1950 to 2005. We investigate national and regional annual means as well as the pan-European mean with respect to trends and reversal periods. 17 of the 24 investigated regions including the pan-European mean show a statistical significant increase since 1990 at the latest. Of the remaining 7 regions, 2 show a non-significant increase, 3 a significant decrease and the remaining 2 no significant trend. The long-term change in DTR is governed by both surface shortwave and longwave radiation, the former of which has undergone a change from dimming to brightening. Consequently, we discuss the connections between DTR, shortwave radiation and sulfur emissions which are thought to be amongst the most important factors influencing the incoming solar radiation through the primary and secondary aerosol effect. We find reasonable agreement between trends in SO2 emissions, radiation and DTR in areas affected by high pollution. Consequently, we conclude that the long-term trends in DTR are mostly determined by changes in emissions and the associated changes in incoming solar radiation.

  15. Diurnal temperature range over Europe between 1950 and 2005

    NASA Astrophysics Data System (ADS)

    Makowski, K.; Wild, M.; Ohmura, A.

    2008-11-01

    It has been widely accepted that diurnal temperature range (DTR) decreased on a global scale during the second half of the twentieth century. Here we show however, that the long-term trend of annual DTR has reversed from a decrease to an increase during the 1970s in Western Europe and during the 1980s in Eastern Europe. The analysis is based on the high-quality dataset of the European Climate Assessment and Dataset Project, from which we selected approximately 200 stations covering the area bordered by Iceland, Algeria, Turkey and Russia for the period 1950 to 2005. We investigate national and regional annual means as well as the pan-European mean with respect to trends and reversal periods. 17 of the 24 investigated regions including the pan-European mean show a statistical significant increase of DTR since 1990 at the latest. Of the remaining 7 regions, two show a non-significant increase, three a significant decrease and two no significant trend. Changes in DTR are affected by both surface shortwave and longwave radiation, the former of which has undergone a change from dimming to brightening in the period considered. Consequently, we discuss the connections between DTR, shortwave radiation and sulfur emissions which are thought to be amongst the most important factors influencing the incoming solar radiation through the primary and secondary aerosol effect. We find reasonable agreement between trends in SO2 emissions, radiation and DTR in areas affected by high pollution. Consequently, we conclude that the trends in DTR could be mostly determined by changes in emissions and the associated changes in incoming solar radiation.

  16. Diurnal temperature range over Europe between 1950 and 2005

    NASA Astrophysics Data System (ADS)

    Makowski, K.; Wild, M.; Ohmura, A.

    2007-12-01

    It has been widely accepted that diurnal temperature range (DTR) decreased on a global scale for the second half of the twentieth century. In contrast, we show that the long-term trend has reversed from decrease to increase during the 1970s in Western Europe and during the 1980s in Eastern Europe. The analysis is based on the high- quality dataset of the European Climate Assessment and Dataset Project, from which we selected about 200 stations, covering the area from Iceland to Algeria and from Turkey to the European part of Russia for 1950 to 2005. We investigate national and regional means as well as the pan-European mean with respect to trends and reversal periods. 17 of the 24 investigated regions including the pan-European mean show a significant increase since 1990 at the latest. Of the remaining 7 regions, 2 show a non-significant increase, 3 a significant decrease and the remaining 2 no significant trend. The long-term change in DTR is considered to depend on both, incoming shortwave radiation and outgoing long-wave radiation, the former of which has undergone a change from dimming to brightening. Consequently we discuss the connections between DTR, shortwave radiation and sulfur emissions which are thought to be amongst the most important factors influencing the incoming solar radiation through the primary and secondary aerosol effect. We find reasonable agreement between trends in SO2 emissions, radiation and DTR in areas affected by high pollution. Consequently we conclude that the long- term trends in DTR are mostly determined by emissions and the incoming solar radiation.

  17. 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

  18. 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

  19. Diurnal cycle of precipitation in a global cloud-resolving model

    NASA Astrophysics Data System (ADS)

    Sato, T.; Miura, H.; Satoh, M.; Takayabu, Y. N.

    2008-12-01

    This study summarizes the diurnal cycle of precipitation that is simulated by a global cloud resolving model (GCRM) named NICAM (Nonhydrostatic ICosahedral Atmospheric Model) which does not use cumulus parameterizations due to high horizontal resolution. Thirty-day integration by NICAM successfully simulates precipitation diurnal cycle associated with land/sea breeze and thermally-induced topographic circulations as well as the horizontal propagation of diurnal cycle signals. A first harmonic of the diurnal cycle of precipitation in 7 km-mesh run agrees very well with the satellite observations in its geographical distributions although the amplitude is slightly overestimated and peak time is 1.5 hour later than that observed over land. Sensitivity experiments, changing the horizontal resolution, suggest that prominent resolution dependence is discernible in the precipitation diurnal cycle in NICAM. The coarser resolution (14 km mesh) run induces about three hour later peak than that in 7 km mesh run. The 3.5 km mesh run realistically produces peak time (around 15 LT) and amplitude similar to those observed in TRMM PR observations. Meanwhile, the resolution dependences in phase and amplitude are negligibly small over ocean domains. The different sensitivity against the horizontal resolution attributes to the different structures and life cycles of convective systems between land and ocean. The NICAM simulation revealed that the diurnal cycle of rainfall over the maritime continent is strongly coupled with the land-sea breeze systems controlling a convergence/divergence pattern in the lower troposphere around the islands. Additionally, the analysis on the cold pool events suggests that the cold pool is often formed over the open ocean where the precipitation intensity is high, and cold pool propagation is related to the diurnal cycle of precipitation as well as the land-sea breeze.

  20. 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.

  1. 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.

  2. The Diurnal Cycle in TOGA-COARE: Regional Scale Model Simulations

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Jia, Y.

    1999-01-01

    The diurnal variation of precipitation processes over the tropics is a well-known phenomenon and has been studied using surface rainfall data, radar reflectivity data, and satellite-derived cloudiness and precipitation. Recently, analyzed observations from Tropical Oceans and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) in the tropical western Pacific ocean to study the relevant mechanisms producing diurnal variation of precipitation. They found that the diurnal Sea surface temperature (SST) cycle is important for afternoon showers in the undisturbed periods and diurnal radiative processes for nocturnal rainfall. Cloud resolving models (CRMS) have been used to determine the mechanisms associated with diurnal variation of precipitating processes. CRMs allow explicit cloud-radiation and air-sea interactive processes. However, CRMs can be only used for idealized simulations (i.e., no feedback between clouds and their embedded large-scale environments; cyclic lateral boundary conditions and idealized initial conditions). In this study, the Penn State/NCAR Mesoscale Model (MM5) with improved physics (i.e., cloud microphysics, radiation, land-soil-vegetation-surface processes, and TOGA COARE flux scheme) and a multiple level nesting technique (covers the TOGA COARE LSA/IFA with a 54 km grid and can nest down to 18, 6 and possibly even 2 km) will be adopted for studying the diurnal variations of rainfall. We will examine precipitation processes over open ocean and over land. We will also perform sensitivity tests to determine how the radiative forcing and diurnal SST cycle affects the development of convection.

  3. Mesoscale Influences of Wind Farms Throughout a Diurnal Cycle

    NASA Astrophysics Data System (ADS)

    Fitch, A. C.; Lundquist, J. K.; Olson, J. B.

    2012-12-01

    Few observations are available to give insight into the interaction between large wind farms and the boundary layer. As wind farm deployment increases, questions are arising on the potential impact on meteorology within and downwind of large wind farms. While large-eddy simulation can provide insight into the detailed interaction between individual turbines and the boundary layer, to date it has been too computationally expensive to simulate wind farms with large numbers of turbines and the resulting wake far downstream. Mesoscale numerical weather prediction models provide the opportunity to investigate the flow in and around large wind farms as a whole, and the resulting impact on meteorology. To this end, we have implemented a wind farm parameterization in the Weather Research and Forecasting (WRF) model, which represents wind turbines by imposing a momentum sink on the mean flow; converting kinetic energy into electricity and turbulent kinetic energy (TKE). The parameterization improves upon previous models, basing the atmospheric drag of turbines on the thrust coefficient of a modern commercial turbine. In addition, the source of TKE varies with wind speed, reflecting the amount of energy extracted from the atmosphere by the turbines that does not produce electrical energy. We simulate a wind farm covering 10x10 km over land, consisting of 100 turbines each of nominal power output of 5 MW. Results will be presented showing how the wake structure varies dramatically over a diurnal cycle characteristic of a region in the Great Plains of the US, where wind farm deployment is planned. At night, a low-level jet forms within the rotor area, which is completely eliminated by energy extraction within the wind farm. The deep stable layer and lack of higher momentum air aloft at this time maximises the wind deficit and the length of the wake. The presentation will discuss the maximum reduction of wind speed within and downwind from the farm, and the wake e

  4. 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

  5. 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

  6. Seasonal variations in the lightning diurnal cycle and implications for the global electric circuit

    NASA Astrophysics Data System (ADS)

    Blakeslee, Richard J.; Mach, Douglas M.; Bateman, Monte G.; Bailey, Jeffrey C.

    2014-01-01

    Data obtained from the Optical Transient Detector and the Lightning Imaging Sensor satellites (70° and 35° inclination low earth orbits, respectively) are used to statistically determine the number of flashes in the seasonal diurnal cycle as a function of local and universal time. These data include corrections for detection efficiency and instrument view time. They are further subdivided by season, land versus ocean, and other spatial (e.g., continents) and temporal (e.g., time of peak diurnal amplitude) categories. These statistics are then combined with analyses of high altitude aircraft observations of electrified clouds to produce the seasonal diurnal variation in the global electric circuit. Continental results display strong diurnal variation, with a lightning peak in the late afternoon and a minimum in late morning. In geographical regions dominated by large mesoscale convective systems, the peak in the diurnal curve shifts toward late evening or early morning hours. The maximum seasonal 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 fall activity at most continental locations. Oceanic lightning exhibits minimal diurnal variation, but morning hours are slightly enhanced over afternoon. As was found earlier, for the annual diurnal variation, using basic assumptions about the mean storm currents as a function of flash rate and location (i.e., land/ocean), our seasonal estimates of the current in the global electric circuit provide an excellent match with independent measurements of the seasonal Carnegie curve diurnal variations. The maximum (minimum) total mean current of 2.4 kA (1.7 kA) is found during Northern Hemisphere summer (winter). Land thunderstorms supply about one half (52%) of the total global current. Ocean thunderstorms contribute about one third (31%) and the non

  7. Diurnal Variations in Blood Flow at Optic Nerve Head and Choroid in Healthy Eyes

    PubMed Central

    Iwase, Takeshi; Yamamoto, Kentaro; Ra, Eimei; Murotani, Kenta; Matsui, Shigeyuki; Terasaki, Hiroko

    2015-01-01

    Abstract To investigate the diurnal variations of the ocular blood flow in healthy eyes using laser speckle flowgraphy (LSFG), and to determine the relationship of the diurnal variations between the ocular blood flow and other ocular parameters. This prospective cross-sectional study was conducted at Nagoya University Hospital. We studied 13 healthy volunteers whose mean age was 33.5 ± 7.6 years. The mean blur rate (MBR), expressing the relative blood flow, on the optic nerve head (ONH) and choroidal blood flow was determined by LSFG (LSFG-NAVI) every 3 hours from 6:00 to 24:00 hours. The intraocular pressure (IOP), choroidal thickness measured by enhanced depth imaging optical coherence tomography, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) in the brachial artery were also recorded. We evaluated the diurnal variations of the parameters and compared the MBR to the other parameters using a linear mixed model. The diurnal variations of the MBR on the ONH varied significantly with a trough at 9:00 hours and a peak at 24:00 hours (P < 0.001, linear mixed model). The MBR of choroid also had significant diurnal variations with a trough at 15:00 hours and a peak at 18:00 hours (P = 0.001). The IOP (P < 0.001), choroidal thickness (P < 0.001), SBP (P = 0.005), DBP (P = 0.001), and HR (P < 0.001) also had significant diurnal variations. Although the diurnal variation of the MBR on the ONH was different from the other parameters, that on the choroid was significantly and positively correlated with the DBP (P = 0.002), mean arterial pressure (P = 0.023), and mean ocular perfusion pressure (P = 0.047). We found significant diurnal variations in the ONH and choroidal blood flow. Although the ONH blood flow had its own diurnal variation because of strong autoregulation, the choroidal blood flow was more likely affected by systemic circulatory factors because of poor autoregulation. PMID:25674750

  8. 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.

  9. Distribution and abundance of diurnal and nocturnal dipterous flies in the Federal Territory, Putrajaya.

    PubMed

    Nazni, W A; Nooraidah, H; Jeffery, J; Azahari, A H; Mohd Noor, I; Sadiyah, I; Lee, H L

    2007-12-01

    A study of diurnal and nocturnal distribution of flies was conducted in Putrajaya. Six different ecological habitats were selected, namely: botanical garden, lake-area, administration building, wetland, jungle fringes and housing areas. Two different type of traps, cylinderical and rectangular in shape were used in the study. Baits used in these traps were yeast, sugar, salted fish, shrimp paste and fresh liver. Traps were placed at the sites throughout the diurnal and nocturnal periods. The time for sunrise and sunset was determined using a Geographical Positioning System gadget (GARMIN) at the sites. Both type of traps were equally effective in trapping flies. There was no significant difference between both types of traps in their ability to trap flies (p > 0.05). A total of 1,534 flies were collected and identified from both types of trap using the multiple baits and habitats. The collection consisted of 23 species of flies classified under 6 families. The highest number of flies were caught from the lake-area followed by botanical garden, administration building, housing areas, wetland and jungle fringes. The most dominant species was Chrysomya megacephala, followed by species of Sarcophagidae and Musca domestica. Diurnal period had more numbers of flies (81.55%) compared to the nocturnal periods (18.45%). Some species of flies were strictly diurnal, some exibited both diurnal and nocturnal activities while only one species was strictly nocturnal. PMID:18209709

  10. Separating selection by diurnal and nocturnal pollinators on floral display and spur length in Gymnadenia conopsea.

    PubMed

    Sletvold, Nina; Trunschke, Judith; Wimmergren, Carolina; Agren, Jon

    2012-08-01

    Most plants attract multiple flower visitors that may vary widely in their effectiveness as pollinators. Floral evolution is expected to reflect interactions with the most important pollinators, but few studies have quantified the contribution of different pollinators to current selection on floral traits. To compare selection mediated by diurnal and nocturnal pollinators on floral display and spur length in the rewarding orchid Gymnadenia conopsea, we manipulated the environment by conducting supplemental hand-pollinations and selective pollinator exclusions in two populations in central Norway. In both populations, the exclusion of diurnal pollinators significantly reduced seed production compared to open pollination, whereas the exclusion of nocturnal pollinators did not. There was significant selection on traits expected to influence pollinator attraction and pollination efficiency in both the diurnal and nocturnal pollination treatment. The relative strength of selection among plants exposed to diurnal and nocturnal visitors varied among traits and populations, but the direction of selection was consistent. The results suggest that diurnal pollinators are more important than nocturnal pollinators for seed production in the study populations, but that both categories contribute to selection on floral morphology. The study illustrates how experimental manipulations can link specific categories of pollinators to observed selection on floral traits, and thus improve our understanding of how species interactions shape patterns of selection. PMID:22928416

  11. 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.

  12. [Effects of Reduced Water and Diurnal Warming on Winter-Wheat Biomass and Soil Respiration].

    PubMed

    Wu, Yang-zhou; Chen, Jian; Hu, Zheng-hua; Xie, Yan; Chen, Shu-tao; Zhang, Xue-song; Shen, Shuang-he; Chen, Xi

    2016-01-15

    Field experiments were conducted in winter wheat-growing season to investigate the effect of reduced water and diurnal warming on wheat biomass and soil respiration. The experimental treatments included the control (CK), 30% reduced water (W), diurnal warming (T, enhanced 2 degrees C), and the combined treatment (TW, 30% reduced water plus diurnal warming 2 degrees C). Soil respiration rate was measured using a static chamber-gas chromatograph technique. The results showed that in the winter wheat-growing season, compared to CK, T and TW treatments significantly increased shoot biomass by 46.0% (P = 0.002) and 19.8% (P = 0.032) during the elongation-booting stage, respectively. T and TW treatments also significantly increased the harvested shoot biomass by 19.8% (P = 0.050) and 34.6% (P = 0.028), respectively. On the other hand, W treatment had no significant effect on shoot biomass, and W, T, and TW treatments didn't significantly change the root biomass. T and W treatments had no significant effect on the mean respiration rate (MRR) of soil (P > 0.05). TW treatment significantly decreased soil MRR by 22.4% (P = 0.049). We also found T treatment decreased the temperature sensitivity coefficients of soil respiration (Q10). The results of our study suggested that compared to the single treatment (reduced water or diurnal warming), the combined treatment (reduced water plus diurnal warming) may have different effects on agroecosystem. PMID:27078968

  13. Diurnal characteristics of lightning flashes detected over the São Paulo lightning mapping array

    NASA Astrophysics Data System (ADS)

    Chronis, T.; Lang, T.; Koshak, W.; Blakeslee, R.; Christian, H.; McCaul, E.; Bailey, J.

    2015-12-01

    This study examines diurnal variations of lightning flash characteristics observed by the Lightning Mapping Array in São Paulo, Brazil. The diurnal flash counts exhibit the typical afternoon convective maximum. The mean source altitude demonstrates a discrete increase that is temporally coincident with the local sunrise. The mean horizontal and vertical flash extents each attain a maximum (minimum) around local sunrise (afternoon, i.e., 13:00-17:00 local solar time). In addition, joint histograms of flash horizontal and vertical extents show that the majority of the flashes occurring during the afternoon convection are shorter and more comparable in size, and the differences between the horizontal and vertical extents are reduced. Conversely, flashes preceding and following the peak in afternoon convection are less symmetric, with larger horizontal than vertical extents. We discuss whether these observations could be partially explained by the diurnal variations in the convectively induced mixing regimes that control thundercloud charge regions and associated charge separation distances. The documented diurnal flash characteristics closely match recently published findings on the diurnal variation of the peak currents of cloud-to-ground flashes. Possible physical mechanisms for these observations are discussed.

  14. 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. PMID:23246705

  15. 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.

  16. 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. PMID:26429581

  17. Diurnal cycles in serotonin acetyltransferase activity and cyclic GMP content of cultured chick pineal glands.

    PubMed

    Wainwright, S D

    1980-06-12

    Levels of serotonin N-acetyltransferase (NAT: acetul CoA:arylamine N-acetyltransferase; EC 2.1.1.5.) activity in the chick pineal gland exhibit a marked diurnal variation in birds kept under a diurnal cycle of ilumination. Activity begins to rise rapidly at the start of the dark phase of the cycle and reaches maximum levels at mid-dark phase about 25-fold greater than the minimum basal level at mid-light phase. Thereafter, the level of activity declines to the basal level about the start of the light phase. This diurnal cycle in chick pineal NAT activity found in vivo has recently been reproduced in vitro with intact glands incubated in organ culture. The mechanism of the 'biological clock' which regulates these variations in level of chick pineal NAT activity is unknown. However, I now report that chick pineal glands cultured under a diurnal cycle of illumination exhibit a diurnal cycle in content of cyclic GMP which roughly parallels the cycles in NAT activity. In contrast, there was no correlation between variations in pineal content of cyclic AMP and in level of NAT activity. PMID:6250035

  18. Variability and reliability of diurnal cortisol in younger and older adults: Implications for design decisions

    PubMed Central

    Segerstrom, Suzanne C.; Boggero, Ian A.; Smith, Gregory T.; Sephton, Sandra E.

    2014-01-01

    The extant research is inconclusive regarding the best sampling methods to construct reliable measures of between-person differences in derived parameters of diurnal cortisol, and no study provides such recommendations for detecting within-person changes. These studies determined how many days of sampling are necessary to assess between-person differences and within-person changes over multiple occasions in diurnal mean, diurnal slope, and area under the curve (AUC). Generalizability and decision analyses were conducted on diurnal salivary cortisol data from two separate longitudinal studies, one with younger adults (N = 124) and one with older adults (N = 148). In both studies, results indicated that 3 days of data collection provided the minimal level of reliability in mean cortisol to detect between-person differences; 4–8 days were necessary to reliably assess AUC, and 10 days for cortisol slope. Similarly, in order to reliably characterize within-person changes across occasions, at least 3 days of data collection were needed for mean cortisol and AUC and 5–8 days for slope. Results also indicated that only two samples per day, taken morning and evening, could faithfully reproduce the diurnal slope calculated from 3 or 4 samples (r = .97–.99). Instead of having participants provide many samples per day over the course of a few days, we recommend collecting fewer samples per day over more days. PMID:25137484

  19. 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

  20. 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.

  1. Evaluating the Diurnal Cycle of Upper Tropospheric Humidity in Two Different Climate Models Using Satellite Observations

    DOE PAGESBeta

    Kottayil, Ajil; John, Viju; Buehler, Stefan; Mohanakumar, Kesavapillai

    2016-04-13

    The diurnal cycle of upper tropospheric humidity (UTH) is known to be influenced by such processes as convection and the formation of clouds which are parameterized in current global climate models. In this study, we evaluate the performance of two climate models, the Community Atmospheric Model version 5 (CAM-5) and the Global Atmosphere 3.0 (GA-3) model in simulating the diurnal cycle of UTH (represented by a combination of sinusoids of 12 and 24 h periods) by comparing with microwave and infrared (IR) measurements (where available). These comparisons were made over two convective land regions in South America and Africa, andmore » over oceanic regions in the Atlantic, Indian and West Pacific for the month of January 2007. We analyzed how the diurnal cycles from IR and microwave instruments differ, and the reason for the differences. Our study suggests that the differences in the diurnal cycles of IR and microwave UTH result from sampling differences due to the presence of clouds. Lastly, as noted by earlier studies, the models exhibit considerable discrepancies in diurnal amplitude and phase relative to observations, and these discrepancies have different magnitudes over land and ocean.« less

  2. 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.

  3. 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.

  4. 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

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

    NASA Astrophysics Data System (ADS)

    Tian, W.

    2016-07-01

    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, 2004). Since then many technical improvements led to a 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.

  6. 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. PMID:19135805

  7. Climatological diurnal variation of negative CG lightning peak current over the continental United States

    NASA Astrophysics Data System (ADS)

    Chronis, T.; Cummins, K.; Said, R.; Koshak, W.; McCaul, E.; Williams, E. R.; Stano, G. T.; Grant, M.

    2015-01-01

    study provides an 11 year climatology of the diurnal variability of the cloud-to-ground (CG) lightning peak current. The local diurnal variation of peak current for negative polarity CG (-CG) flashes exhibits a highly consistent behavior, with increasing magnitudes between the late night to early morning hours and decreasing magnitudes during the afternoon. Over most regions, an inverse relationship exists between the -CG peak current and the corresponding -CG activity, although specific details can depend on region and time of day. Overall, the diurnal variation of the -CG peak current appears to reflect fundamental differences between morning and afternoon storms, but additional studies are required to clearly identify the primary cause(s).

  8. A study of the diurnal variation in the thermosphere as derived by satellite drag

    NASA Technical Reports Server (NTRS)

    Jacchia, L. G.; Campbell, I. G.; Slowey, J. W.

    1973-01-01

    An analysis was performed on 29,574 densities derived from the drag of 10 satellites to determine simultaneously the parameters of the solar-activity effect in the thermosphere on the one hand, and the amplitude and shape of the diurnal-variation curve on the other. This paper reports on the study of the diurnal variation only. Although a considerable amount of smoothing is inherent in the drag method, it seemed useful to see whether any change could be detected in the shape of the diurnal-variation curve with height, latitude and solar activity. None was detected; the curve remains remarkably stable, symmetric, with a maximum at 14 hr 20 min L.S.T. and a minimum at 2 hr 20 min L.S.T. A systematic variation of the temperature range with height is observed when static models are used to derive it.

  9. Diurnal cycle on the Caribbean slope of Costa Rica: An observational study

    NASA Astrophysics Data System (ADS)

    Amador, J. A.; Saenz, F.

    2013-05-01

    The atmospheric diurnal cycle in tropical regions under different atmospheric environments is crucial to understand the role of convective activity (both, thermal and mechanical) in the global circulation energy budget. Many of the physical mechanisms involved in the diurnal cycle, such as the land-sea and mountain-valley breezes, are not well understood, partly because of lack of observational studies and the deficiencies shown by numerical models to capture the essence of the process. Studies of the diurnal cycle, and its interaction with other processes at different time and space scales, such as trade winds, have been relatively scarce. In this paper, preliminary results are presented for available observational data of precipitation and wind from several automatic meteorological stations in order to identify major features of the mean diurnal cycle on the Caribbean slope of Costa Rica. The analyzed region includes a relatively flat area near the coast and a mountain range to its west, being partly influenced by the trade wind system all year round. This factor provides the opportunity to investigate the diurnal cycle under different synoptic and climate conditions. Data consists of a set of 19 stations with hourly resolution for 2006-2011and 8 stations for 2000-2006. The spatial distribution of the stations covers a transect of about 350 km long, which allows a wide range of topographical conditions to be considered. Observational results over the region show a large contrast among the stations in the mean precipitation diurnal cycle patterns that seem to be the result of the interaction of the large scale environment (trades), the local land-sea characteristics, and the topography.

  10. 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.