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Sample records for iiasa rains model

  1. The IIASA set of energy models: Its design and application

    NASA Astrophysics Data System (ADS)

    Basile, P. S.; Agnew, M.; Holzl, A.; Kononov, Y.; Papin, A.; Rogner, H. H.; Schrattenholzer, L.

    1980-12-01

    The models studied include an accounting framework type energy demand model, a dynamic linear programming energy supply and conversion system model, an input-output model, a macroeconomic model, and an oil trade gaming model. They are incorporated in an integrated set for long-term, global analyses. This set makes use of a highly iterative process for energy scenario projections and analyses. Each model is quite simple and straightforward in structure; a great deal of human judgement is necessary in applying the set. The models are applied to study two alternative energy scenarios for a coming fifty year period. Examples are presented revealing the wealth of information that can be obtained from multimodel techniques. Details are given for several models (equations employed, assumptions made, data used).

  2. IIASA`s climate-vegetation-biogeochemical cycle module as a part of an integrated model for climate change

    SciTech Connect

    Ganopolski, A.V.; Jonas, M.; Krabec, J.; Olendrzynski, K.; Petoukhov, V.K.; Venevsky, S.V.

    1994-12-31

    The main objective of this study is the development of a hierarchy of coupled climate biosphere models with a full description of the global biogeochemical cycles. These models are planned for use as the core of a set of integrated models of climate change and they will incorporate the main elements of the Earth system (atmosphere, hydrosphere, pedosphere and biosphere) linked with each other (and eventually with the antroposphere) through the fluxes of heat, momentum, water and through the global biogeochemical cycles of carbon and nitrogen. This set of integrated models can be considered to fill the gap between highly simplified integrated models of climate change and very sophisticated and computationally expensive coupled models, developed on the basis of general circulation models (GCMs). It is anticipated that this range of integrated models will be an effective tool for investigating the broad spectrum of problems connected with the coexistence of human society and biosphere.

  3. IIASA Energy Study unveiled

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    Meeting the energy needs of the world in 2030, when the projected population will be 8 billion, can be done, but not without international cooperation, a mix of energy technologies, and an understanding of the dependence of resources and use. That's the optimistic conclusion of the 7-year golbal energy study by the International Insitute for Applied Systems Analysis (IIASA).

  4. Fellowship Available: 2005 IIASA Young Scientists Summer Program

    NASA Astrophysics Data System (ADS)

    2004-12-01

    The International Institute for Applied Systems Analysis (IIASA) near Vienna, Austria, will host its annual Young Scientists's Summer Program (YSSP) for a selected group of graduate students from around the world. These students, primarily doctoral, will work closely with IIASA's senior scientists on projects within the institute's theme areas: natural resources and environment (e.g., transboundary air pollution and greenhouse gas initiative), population and society (e.g., risk, modeling, and society, and sustainable rural development), and energy and technology (e.g., transitions to new technologies and dynamic systems). Applicants must be advanced graduate students at a U.S. university; have comparable experience with ongoing research at IIASA; students who would benefit from interactions with scientists worldwide; and be interested in investigating the policy implications of his/her work.The U.S. Committee for IIASA provides airfare and a living allowance for those selected to participate in the fellowship.

  5. Acid rain: Mesoscale model

    NASA Technical Reports Server (NTRS)

    Hsu, H. M.

    1980-01-01

    A mesoscale numerical model of the Florida peninsula was formulated and applied to a dry, neutral atmosphere. The prospective use of the STAR-100 computer for the submesoscale model is discussed. The numerical model presented is tested under synoptically undisturbed conditions. Two cases, differing only in the direction of the prevailing geostrophic wind, are examined: a prevailing southwest wind and a prevailing southeast wind, both 6 m/sec at all levels initially.

  6. Acid rain: Microphysical model

    NASA Technical Reports Server (NTRS)

    Dingle, A. N.

    1980-01-01

    A microphysical model was used to simulate the case of a ground cloud without dilution by entrainment and without precipitation. The numerical integration techniques of the model are presented. The droplet size spectra versus time and the droplet molalities for each value of time are discussed.

  7. A probability distribution model for rain rate

    NASA Technical Reports Server (NTRS)

    Kedem, Benjamin; Pavlopoulos, Harry; Guan, Xiaodong; Short, David A.

    1994-01-01

    A systematic approach is suggested for modeling the probability distribution of rain rate. Rain rate, conditional on rain and averaged over a region, is modeled as a temporally homogeneous diffusion process with appropiate boundary conditions. The approach requires a drift coefficient-conditional average instantaneous rate of change of rain intensity-as well as a diffusion coefficient-the conditional average magnitude of the rate of growth and decay of rain rate about its drift. Under certain assumptions on the drift and diffusion coefficients compatible with rain rate, a new parametric family-containing the lognormal distribution-is obtained for the continuous part of the stationary limit probability distribution. The family is fitted to tropical rainfall from Darwin and Florida, and it is found that the lognormal distribution provides adequate fits as compared with other members of the family and also with the gamma distribution.

  8. A scattering model for rain depolarization

    NASA Technical Reports Server (NTRS)

    Wiley, P. H.; Stutzman, W. L.; Bostian, C. W.

    1973-01-01

    A method is presented for calculating the amount of depolarization caused by precipitation for a propagation path. In the model the effects of each scatterer and their interactions are accounted for by using a series of simplifying steps. It is necessary only to know the forward scattering properties of a single scatterer. For the case of rain the results of this model for attenuation, differential phase shift, and cross polarization agree very well with the results of the only other model available, that of differential attenuation and differential phase shift. Calculations presented here show that horizontal polarization is more sensitive to depolarization than is vertical polarization for small rain drop canting angle changes. This effect increases with increasing path length.

  9. MULTIDIMENSIONAL MODELING OF CORONAL RAIN DYNAMICS

    SciTech Connect

    Fang, X.; Xia, C.; Keppens, R.

    2013-07-10

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  10. Multidimensional Modeling of Coronal Rain Dynamics

    NASA Astrophysics Data System (ADS)

    Fang, X.; Xia, C.; Keppens, R.

    2013-07-01

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  11. Heavy pollution suppresses light rain in China: observations and modeling

    SciTech Connect

    Qian, Yun; Gong, Daoyi; Fan, Jiwen; Leung, Lai R.; Bennartz, Ralph; Chen, Deliang; Wang, Weiguo

    2009-08-15

    Long-term observational data reveal that both the frequency and amount of light rain have decreased in eastern China (EC) for 1956-2005 with high spatial coherency. This is different from the trend of total rainfall observed in EC, which decreases in northern EC and increases in southern EC. To examine the cause of the light rain trends, we analyzed the long-term variability of atmospheric water vapor and its correlation with light rain events. Results show very weak relationships between large-scale moisture transport and light rain in EC. This suggests that light rain trend in EC is not driven by large-scale circulation changes. Because of human activities, pollutant emission has increased dramatically in China for the last few decades, leading to significant reductions in visibility between 1960 and 2000. Cloud-resolving model simulations show that aerosols corresponding to heavily polluted conditions can significantly increase the cloud droplet number concentration (CDNC) and reduce droplet sizes compared to pristine conditions. This can lead to a significant decline in raindrop concentration and delay raindrop formation because smaller cloud droplets are less efficient in the collision and coalescence processes. Together with weaker convection, the precipitation frequency and amount are significantly reduced in the polluted case. Satellite data also reveal higher CDNC and smaller droplet size over polluted land in EC relative to pristine regions, which is consistent with the model results. This evidence suggests that the significantly increased aerosol particles produced by air pollution are at least partly responsible for the decreased light rain events observed in China over the past fifty years.

  12. Comparison between natural Rain drop size distributions and corresponding models near equilibrium state during warm rain

    NASA Astrophysics Data System (ADS)

    Barthes, Laurent; Mallet, Cécile

    2010-05-01

    Keywords: Rain Drop Size Distribution, Breakup, coalescence, disdrometer The study of the vertical evolution of raindrop size distributions (DSDs) during rainfall, from the freezing level isotherm to ground level, is a key to improving our understanding of the microphysics of rain. In numerous domains such as remote sensing, telecommunications, soil erosion, and the study of the rain's efficiency in 'washing' the atmosphere, the DSD plays an important role. Among the different processes affecting the evolution of DSD, breakup and coalescence are two of the most significant. Models of coalescence and breakup lead to equilibrium of the raindrop size distribution (DSD) after a fall through sufficient vertical height. At equilibrium, the DSD no longer evolves, and its shape is unique whatever the rain rate or LWC. This implies that the DSD is known, to within a multiplication constant. These models based on experimental measurements have been developed over the past 40 years. The Low and List (1982a,b) parameterization (hereinafter LL82) and the Greg M. McFarquhar (2004) model are both based on the same laboratory experiments, which lead to an equilibrium drop size distribution (EDSD) with two or three peaks, and an exponential tail with a slope of approximately Λ=65 cm-1. Numerous measurements using disdrometer collected in different climatic areas: Paris, France (Mars to October 2000), Iowa-City (April to October 2002), and Djougou (Benin June to September 2006) corresponding to 537 hours of rain period have shown that for high rain rates, close to a state of equilibrium, this slope lies between Λ=20 - 22 cm-1. This latter value is corroborated by others measurements found in the literature (Hu & Srivastava, 1995). Hu & Srivastava suggested that the Low and List parameterization may overestimate the effects of the breakup process. This hypothesis is in adequation with recent laboratory experiments (A.P. Barros 2008) in which the authors conclude that the number of

  13. A collaborative effort to model plant response to acidic rain

    SciTech Connect

    Jacobson, J.; Irving, P.; Kuja, A.; Lee, J.; Shriner, D.; Troiano, J.; Perrigan, S.; Cullinan, V.

    1989-01-01

    Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain on dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. 14 refs., 2 figs., 7 tabs.

  14. A meteorological potential forecast model for acid rain in Fujian Province, China.

    PubMed

    Cai, Yi Yong; Lin, Chang Cheng; Liu, Jing Xiong; Wu, De Hui; Lian, Dong Ying; Chen, Bin Bin

    2010-05-01

    Based on the acid rain and concurrent meteorological observational data during the past 10 years in Fujian Province, China, the dependence of distribution characteristics of acid rain on season, rain rate, weather pattern and dominant airflow in four regions of Fujian Province is analyzed. On the annual average, the acid rain frequency is the highest (above 40%) in the southern and mid-eastern regions, and the lowest (16.2%) in the western region. The acid rain occurs most frequently in spring and winter, and least frequent in summer. The acid rain frequency in general increases with the increase of precipitation. It also depend on the direction of dominant airflows at 850 hPa. In the mid-eastern region, more than 40% acid rains appear when the dominant wind directions are NW, W, SW, S and SE. In the southern region, high acid rain occurrence happens when the dominant wind directions are NW, W, SW and S. In the northern region, 41.8% acid rains occur when the southwesterly is pronounced. In the western region, the southwesterly is associated with a 17% acid rain rate. The examination of meteorological sounding conditions over Fuzhou, Xiamen and Shaowu cities shows that the acid rain frequency increases with increased inversion thickness. Based on the results above, a meteorological potential forecast model for acid rain is established and tested in 2007. The result is encouraging. The model provides an objective basis for the development of acid rain forecasting operation in the province.

  15. A simple model for the estimation of rain-induced attenuation along earth-space paths at millimeter wavelengths

    NASA Technical Reports Server (NTRS)

    Stutzman, W. L.; Dishman, W. K.

    1982-01-01

    A simple attenuation model (SAM) is presented for estimating rain-induced attenuation along an earth-space path. The rain model uses an effective spatial rain distribution which is uniform for low rain rates and which has an exponentially shaped horizontal rain profile for high rain rates. When compared to other models, the SAM performed well in the important region of low percentages of time, and had the lowest percent standard deviation of all percent time values tested.

  16. A simple model for the estimation of rain-induced attenuation along earth-space paths at millimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Stutzman, W. L.; Dishman, W. K.

    1982-12-01

    A simple attenuation model (SAM) is presented for estimating rain-induced attenuation along an earth-space path. The rain model uses an effective spatial rain distribution which is uniform for low rain rates and which has an exponentially shaped horizontal rain profile for high rain rates. When compared to other models, the SAM performed well in the important region of low percentages of time, and had the lowest percent standard deviation of all percent time values tested.

  17. Millimeter wave propagation modeling of inhomogeneous rain media for satellite communications systems

    NASA Technical Reports Server (NTRS)

    Persinger, R. R.; Stutzman, W. L.

    1978-01-01

    A theoretical propagation model that represents the scattering properties of an inhomogeneous rain often found on a satellite communications link is presented. The model includes the scattering effects of an arbitrary distribution of particle type (rain or ice), particle shape, particle size, and particle orientation within a given rain cell. An associated rain propagation prediction program predicts attenuation, isolation and phase shift as a function of ground rain rate. A frequency independent synthetic storm algorithm is presented that models nonuniform rain rates present on a satellite link. Antenna effects are included along with a discussion of rain reciprocity. The model is verified using the latest available multiple frequency data from the CTS and COMSTAR satellites. The data covers a wide range of frequencies, elevation angles, and ground site locations.

  18. Introduction of prognostic rain in ECHAM5: design and Single Column Model simulations

    NASA Astrophysics Data System (ADS)

    Posselt, R.; Lohmann, U.

    2007-10-01

    Prognostic equations for the rain mass mixing ratio and the rain drop number concentration are introduced into the large-scale cloud microphysics parameterization of the ECHAM5 general circulation model (ECHAM5-RAIN). For this a rain flux from one level to the next with the appropriate fall speed is introduced. This maintains rain water in the atmosphere to be available for the next time step. Rain formation in ECHAM5-RAIN is, therefore, less dependent on the autoconversion rate than the standard ECHAM5 but shifts the emphasis towards the accretion rates in accordance with observations. ECHAM5-RAIN is tested and evaluated with two cases: the continental mid-latitude ARM Cloud IOP (shallow frontal cloud case - March 2000) and EPIC (a marine stratocumulus study - October 2001). The prognostic equations for rain hardly affect the amount and timing of precipitation at the surface in different Single Column Model (SCM) simulations for heavy precipitating clouds because heavy rain depends mainly on the large-scale forcing. In case of thin, drizzling clouds (i.e., stratocumulus), an increase in surface precipitation is caused by more sub-time steps used in the prognostic rain scheme until convergence is reached. Cloud microphysical quantities, such as liquid and rain water, are more sensitive to the number of sub-time steps for light precipitation. This results from the decreasing autoconversion rate and increasing accretion rate.

  19. Analysis of Rain Attenuation Models for South East Asia Countries

    NASA Astrophysics Data System (ADS)

    Mandeep, J. S.; Nalinggam, Renuka; Bt Ismail, Widad

    2011-02-01

    This paper presents an analysis of experimental data compared with existing rain attenuation prediction models, namely, the Yamada, R&K, Crane, DAH and ITU models, which have been previously used in satellite communication systems. The experimental data were measured at the Universiti Sains Malaysia, Penang in the northern region of Peninsular Malaysia from 2007 to 2009 by receiving a Ku-band signal from the satellite SuperBird-C (geostationary at 144 °E). Data from Nigeria, Kenya, Indonesia, and PNG were obtained from the respective countries' researchers. The DAH and ITU models were recommended as the most suitable models. The recommendation was made based on the model's good performance compared with the measured data from the selected tropical countries.

  20. Collaborative effort to model plant response to acidic rain

    SciTech Connect

    Jacobson, J.; Kuja, A.; Shriner, D.; Perrigan, S.; Irving, P.; Lee, J.; Troiano, J.; Cullinan, V.

    1988-06-01

    Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain or dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. When the laboratory by trial effect was removed, lack of fit to the Mitscherlich function was insignificant. Thus, a single mathematical model satisfactorily characterized the relationship between acidity and mean plant response.

  1. Introduction of prognostic rain in ECHAM5: design and single column model simulations

    NASA Astrophysics Data System (ADS)

    Posselt, R.; Lohmann, U.

    2008-06-01

    Prognostic equations for the rain mass mixing ratio and the rain drop number concentration are introduced into the large-scale cloud microphysics parameterization of the ECHAM5 general circulation model (ECHAM5-PROG). To this end, a rain flux from one level to the next with the appropriate fall speed is introduced. This maintains rain water in the atmosphere to be available for the next time step. Rain formation in ECHAM5-PROG is, therefore, less dependent on the autoconversion rate than the standard ECHAM5 but shifts the emphasis towards the accretion rates in accordance with observations. ECHAM5-PROG is tested and evaluated with Single Column Model (SCM) simulations for two cases: the marine stratocumulus study EPIC (October 2001) and the continental mid-latitude ARM Cloud IOP (shallow frontal cloud case - March 2000). In case of heavy precipitation events, the prognostic equations for rain hardly affect the amount and timing of precipitation at the surface in different SCM simulations because heavy rain depends mainly on the large-scale forcing. In case of thin, drizzling clouds (i.e., stratocumulus), surface precipitation is sensitive to the number of sub-time steps used in the prognostic rain scheme. Cloud microphysical quantities, such as cloud liquid and rain water within the atmosphere, are sensitive to the number of sub-time steps in both considered cases. This results from the decreasing autoconversion rate and increasing accretion rate.

  2. Slant path rain attenuation comparison of prediction models for satellite applications in Malaysia

    NASA Astrophysics Data System (ADS)

    Mandeep, J. S.

    2009-09-01

    A 2-year campaign of slant path rain attenuation measurements has been carried out in Malaysia using the Superbird-C satellite beacon at 12.255 GHz. The rain intensity time series have been recorded with a conventional tipping-bucket rain gauge located at the station, during a continuous observation period spanning the same 2 years of the beacon measurements. The experimental cumulative distributions of rainfall rate and rain attenuation are presented. Two years of rain attenuation measurements at 12.255 GHz shows high values that have been detected for small percentage of time; for example, the attenuation exceeded 25 dB for 0.01% of time. The rainfall rate is compared with International Telecommunications Union-Radiocommunication (ITU-R) maps, and the measured rain rate distribution is close to that derived from the ITU-R maps. Measured rain attenuation values are compared with several prediction models. A good agreement has been found in the comparison of the experimental distribution with some prediction models (Ramachandran, Bryant, Matricciani, and Exponential Cell (EXCELL) with percentage errors below 11%) calculated using the measured rainfall rate distribution. The lack of rain measurement data from equatorial and tropical regions for verification causes predictions obtained from existing models to deviate from direct measurements.

  3. Comparing Satellite Rainfall Estimates with Rain-Gauge Data: Optimal Strategies Suggested by a Spectral Model

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Kundu, Prasun K.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Validation of satellite remote-sensing methods for estimating rainfall against rain-gauge data is attractive because of the direct nature of the rain-gauge measurements. Comparisons of satellite estimates to rain-gauge data are difficult, however, because of the extreme variability of rain and the fact that satellites view large areas over a short time while rain gauges monitor small areas continuously. In this paper, a statistical model of rainfall variability developed for studies of sampling error in averages of satellite data is used to examine the impact of spatial and temporal averaging of satellite and gauge data on intercomparison results. The model parameters were derived from radar observations of rain, but the model appears to capture many of the characteristics of rain-gauge data as well. The model predicts that many months of data from areas containing a few gauges are required to validate satellite estimates over the areas, and that the areas should be of the order of several hundred km in diameter. Over gauge arrays of sufficiently high density, the optimal areas and averaging times are reduced. The possibility of using time-weighted averages of gauge data is explored.

  4. Model-estimated microwave emissions from rain systems for remote sensing applications

    NASA Astrophysics Data System (ADS)

    Smirnov, Mikhail T.; Meischner, Peter F.

    1996-12-01

    A simple model for estimating the upward and downward microwave emission from rain layer types above ground is presented. The emission properties of the rain layers are estimated from physical quantities such as the optical depth, the single-scattering albedo, the physical temperature, and a given drop size distribution for Mie scattering calculations. The underlying surface is characterized by the emissivity and the physical temperature. The transparency coefficient q and the reflection coefficient r of the rain layer are expressed by these physical quantities. The brightness temperature then is given by the physical temperature T, q, and r. The radiation transfer is estimated by the method of layer addition, described by Sobolev [1956], which avoids the necessity of solving the equation of radiation transfer. The accuracy of this simple model was estimated by comparisons with three-dimensional Monte Carlo calculations. The error is estimated to be less than 3 K for common situations and less than 8 K for unrealistic high optical depths. It is shown that any one of the quantities rain rate, rain layer depth, and physical temperature can be estimated with sufficient accuracy if the others are known. The basic model has been extended for application to inhomogeneous cloud layers and to include differences in brightness temperatures for horizontal and vertical polarizations for oblate raindrops. The main intended application of this model is rain rate estimation from space with low data processing efforts, especially for the Priroda mission. The model was tested for the downwelling emission during the field experiment CLEOPATRA by measurements with a polarimetric weather radar and rain gauges. The results verify the principles, and promising agreement was found at least for stratiform rain. The polarimetric extension of the model too showed promising results under quite different measurement conditions in Russia and southern Germany.

  5. Comparison of rain gauge and radar data as input to an urban rainfall-runoff model.

    PubMed

    Quirmbach, M; Schultz, G A

    2002-01-01

    This paper presents an application of radar data (DX-product of the German Weather Service) with a high resolution in space (1 degree x 1 km) and time (delta t = 5 minutes) in urban hydrology. The radar data and data of rain gauges with different locations in the test catchment were compared concerning their suitability as input into an urban rainfall-runoff model. In order to evaluate the accuracy of model simulation results, five evaluation criteria have been specified which are relevant for an efficient management of sewer systems and wastewater treatment plants. The results demonstrate that radar data should be used in urban hydrology if distances > 4 km between rain gauge and catchment exist and for catchments with a density of rain gauges smaller than 1 rain gauge per 16 km2.

  6. A two-component rain model for the prediction of attenuation statistics

    NASA Technical Reports Server (NTRS)

    Crane, R. K.

    1982-01-01

    A two-component rain model has been developed for calculating attenuation statistics. In contrast to most other attenuation prediction models, the two-component model calculates the occurrence probability for volume cells or debris attenuation events. The model performed significantly better than the International Radio Consultative Committee model when used for predictions on earth-satellite paths. It is expected that the model will have applications in modeling the joint statistics required for space diversity system design, the statistics of interference due to rain scatter at attenuating frequencies, and the duration statistics for attenuation events.

  7. A heterogeneous chemistry model for acid rain`s effect on ozone

    SciTech Connect

    Ye, Tao

    1995-11-01

    A computer model for simulating heterogeneous reactions in cloud is developed to determine the S(IV) species` effect on ozone. Crutzen claims that NO{sub x}, HO{sub x} families and H{sub 2}CO in the troposphere can decrease ozone by 5 to 10%. However, is this claim valid for a SO{sub x} polluted atmosphere? The SO{sub x} family reacts with the ozone destroyers. These reactions seem to be significant enough to reduce the H{sub 2}CO`s destructive effect on ozone.

  8. Aerosol effect on the warm rain formation process: Satellite observations and modeling

    NASA Astrophysics Data System (ADS)

    Suzuki, Kentaroh; Stephens, Graeme L.; Lebsock, Matthew D.

    2013-01-01

    This study demonstrates how aerosols influence the liquid precipitation formation process. This demonstration is provided by the combined use of satellite observations and global high-resolution model simulations. Methodologies developed to examine the warm cloud microphysical processes are applied to both multi-sensor satellite observations and aerosol-coupled global cloud-resolving model (GCRM) results to illustrate how the warm rain formation process is modulated under different aerosol conditions. The observational analysis exhibits process-scale signatures of rain suppression due to increased aerosols, providing observational evidence of the aerosol influence on precipitation. By contrast, the corresponding statistics obtained from the model show a much faster rain formation even for polluted aerosol conditions and much weaker reduction of precipitation in response to aerosol increase. It is then shown that this reduced sensitivity points to a fundamental model bias in the warm rain formation process that in turn biases the influence of aerosol on precipitation. A method of improving the model bias is introduced in the context of a simplified single-column model (SCM) that represents the cloud-to-rain water conversion process in a manner similar to the original GCRM. Sensitivity experiments performed by modifying the model assumptions in the SCM and their comparisons to satellite statistics both suggest that the auto-conversion scheme has a critical role in determining the precipitation response to aerosol perturbations and also provide a novel way of constraining key parameters in the auto-conversion schemes of global models.

  9. Morphology of Rain Water Channeling in Systematically Varied Model Sandy Soils

    NASA Astrophysics Data System (ADS)

    Wei, Yuli; Cejas, Cesare M.; Barrois, Rémi; Dreyfus, Rémi; Durian, Douglas J.

    2014-10-01

    We visualize the formation of fingered flow in dry model sandy soils under different rain conditions using a quasi-2D experimental setup and systematically determine the impact of the soil grain diameter and surface wetting properties on the water channeling phenomenon. The model sandy soils we use are random closely packed glass beads with varied diameters and surface treatments. For hydrophilic sandy soils, our experiments show that rain water infiltrates a shallow top layer of soil and creates a horizontal water wetting front that grows downward homogeneously until instabilities occur to form fingered flows. For hydrophobic sandy soils, in contrast, we observe that rain water ponds on the top of the soil surface until the hydraulic pressure is strong enough to overcome the capillary repellency of soil and create narrow water channels that penetrate the soil packing. Varying the raindrop impinging speed has little influence on water channel formation. However, varying the rain rate causes significant changes in the water infiltration depth, water channel width, and water channel separation. At a fixed rain condition, we combine the effects of the grain diameter and surface hydrophobicity into a single parameter and determine its influence on the water infiltration depth, water channel width, and water channel separation. We also demonstrate the efficiency of several soil water improvement methods that relate to the rain water channeling phenomenon, including prewetting sandy soils at different levels before rainfall, modifying soil surface flatness, and applying superabsorbent hydrogel particles as soil modifiers.

  10. A two-component rain model for the prediction of attenuation and diversity improvement

    NASA Technical Reports Server (NTRS)

    Crane, R. K.

    1982-01-01

    A new model was developed to predict attenuation statistics for a single Earth-satellite or terrestrial propagation path. The model was extended to provide predictions of the joint occurrences of specified or higher attenuation values on two closely spaced Earth-satellite paths. The joint statistics provide the information required to obtain diversity gain or diversity advantage estimates. The new model is meteorologically based. It was tested against available Earth-satellite beacon observations and terrestrial path measurements. The model employs the rain climate region descriptions of the Global rain model. The rms deviation between the predicted and observed attenuation values for the terrestrial path data was 35 percent, a result consistent with the expectations of the Global model when the rain rate distribution for the path is not used in the calculation. Within the United States the rms deviation between measurement and prediction was 36 percent but worldwide it was 79 percent.

  11. A Stochastic Fractional Dynamics Model of Space-time Variability of Rain

    NASA Technical Reports Server (NTRS)

    Kundu, Prasun K.; Travis, James E.

    2013-01-01

    Rainfall varies in space and time in a highly irregular manner and is described naturally in terms of a stochastic process. A characteristic feature of rainfall statistics is that they depend strongly on the space-time scales over which rain data are averaged. A spectral model of precipitation has been developed based on a stochastic differential equation of fractional order for the point rain rate, that allows a concise description of the second moment statistics of rain at any prescribed space-time averaging scale. The model is thus capable of providing a unified description of the statistics of both radar and rain gauge data. The underlying dynamical equation can be expressed in terms of space-time derivatives of fractional orders that are adjusted together with other model parameters to fit the data. The form of the resulting spectrum gives the model adequate flexibility to capture the subtle interplay between the spatial and temporal scales of variability of rain but strongly constrains the predicted statistical behavior as a function of the averaging length and times scales. We test the model with radar and gauge data collected contemporaneously at the NASA TRMM ground validation sites located near Melbourne, Florida and in Kwajalein Atoll, Marshall Islands in the tropical Pacific. We estimate the parameters by tuning them to the second moment statistics of radar data. The model predictions are then found to fit the second moment statistics of the gauge data reasonably well without any further adjustment.

  12. A Unified Statistical Rain-Attenuation Model for Communication Link Fade Predictions and Optimal Stochastic Fade Control Design Using a Location-Dependent Rain-Statistic Database

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1990-01-01

    A static and dynamic rain-attenuation model is presented which describes the statistics of attenuation on an arbitrarily specified satellite link for any location for which there are long-term rainfall statistics. The model may be used in the design of the optimal stochastic control algorithms to mitigate the effects of attenuation and maintain link reliability. A rain-statistics data base is compiled, which makes it possible to apply the model to any location in the continental U.S. with a resolution of 0-5 degrees in latitude and longitude. The model predictions are compared with experimental observations, showing good agreement.

  13. A Model for Estimation of Rain Rate on Tropical Land from TRMM Microwave Imager Radiometer Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Kim, Kyu-Myong

    2004-01-01

    Over the tropical land regions observations of the 85 GHz brightness temperature (T(sub 85v)) made by the TRMM Microwave Imager (TMI) radiometer when analyzed with the help of rain rate (R(sub pR)) deduced from the TRMM Precipitation Radar (PR) indicate that there are two maxima in rain rate. One strong maximum occurs when T(sub 85) has a value of about 220 K and the other weaker one when T(sub 85v) is much colder approx. 150 K. Together with the help of earlier studies based on airborne Doppler Radar observations and radiative transfer theoretical simulations, we infer the maximum near 220 K is a result of relatively weak scattering due to super cooled rain drops and water coated ice hydrometeors associated with a developing thunderstorm (Cb) that has a strong updraft. The other maximum is associated with strong scattering due to ice particles that are formed when the updraft collapses and the rain from the Cb is transit2oning from convective type to stratiform type. Incorporating these ideas and with a view to improve the estimation of rain rate from existing operational method applicable to the tropical land areas, we have developed a rain retrieval model. This model utilizes two parameters, that have a horizontal scale of approx. 20km, deduced from the TMI measurements at 19, 21 and 37 GHz (T(sub 19v), T(sub 21v), T(sub 37v). The third parameter in the model, namely the horizontal gradient of brightness temperature within the 20 km scale, is deduced from TMI measurements at 85 GHz. Utilizing these parameters our retrieval model is formulated to yield instantaneous rain rate on a scale of 20 km and seasonal average on a mesoscale that agree well with that of the PR.

  14. Spatiotemporal rain-fed wheat modeling using a land surface model and a crop stress index

    NASA Astrophysics Data System (ADS)

    Ghazanfari, Sadegh; Alizadeh, Amin; Faridhosseini, Alireza; Pande, Saket

    2013-04-01

    Rain-fed wheat yield estimation is an important issue in crop modeling. Regression and empirical equations are generally used to estimate wheat yields based on effective factors. These equations also need to be calibrated for each study area. Further, employing inaccurate inputs increases prediction uncertainty. Precipitation is the most important input for the rain-fed crops modeling and often interpolated data for areas without rain gauges is used. In this study, the outputs of two precipitation estimation models based on remotely sensed data, PERSIANN and TRMM, are used as alternatives to interpolated data. Results show that the precipitation estimation models outputs are more correlated with observed data than the interpolated precipitation data. Correlation coefficient at a meteorological station in Iran based on Kendall's test is 0.8 for PERSIANN while it is 0.4 and 0.5 for two interpolation methods, Inverse Distance Weighting and Kriging respectively. A simple evaporation/transpiration scheme (SETS), which is a distributed land surface model, has also been developed to estimate actual evaporation and transpiration. Finally a new crop stress index based on actual by potential transpiration (APT) is introduced to model crop yield by using SETS outputs at field scale. Results show that modeling crop yields based on APT, when SETS is forced by local field datasets at 10 sites, can estimate yields reasonably well when compared with other methods. The correlation coefficient with the observed yield data is at least 0.5 and the LSD (Least Significant Difference) test show no significant difference between measured and modeled yields at all sites. Our estimation method performs better than other methods in estimating yields based on the yields predicted by the other methods at the same sites.

  15. Rain rate modeling of 1-min from various integration times in South Korea.

    PubMed

    Shrestha, Sujan; Park, Jung-Jin; Choi, Dong-You

    2016-01-01

    Rain plays a major impairment factor for propagation of electromagnetic waves in atmosphere for systems operating at frequencies above 10 GHz. Several effects are noted such as depolarization, scintillation, interference due to scattering and extra attenuation which seems to increase with frequency. To mitigate its effect in satellite communication, knowledge of local rainfall statistics is necessary which act as milestone for design of radio link. Rain attenuation is best visualize by the 1-min rainfall rate statistic but the measurement of this rain rate distribution is rare on a worldwide basis and observation of rain rate are done with longer integration times typically 30 min or more. In this paper, efforts have been made to develop model that can convert rain rate complementary cumulative distribution function to shorter integration times. The average relative error margin of about 5, 14, 43, 71 and 115 % are noted for 5 to 1-, 10 to 1-, 20 to 1, 30 to 1- and 60 to 1-min respectively from ITU-R P.837-6 method which have been analyzed in further section of this article. The empirical natures of conversion methods as such Segal method, Burgueno's method, Chebil and Rahman method and Logarithmic model are studied along with the proposed new model that seems to be applicable in derivation of 1-min rain rate of the South Korea rain rate statistics. International Telecommunication Union-Radio communication Sector (ITU-R) has developed a recommendation ITU-R P.837-6 that enables the user to estimate the local 1-min rainfall rate statistical distribution which is compared with calculated 1-min rain rate distribution from experimental 1-min rainfall accumulation. Unfortunately, ITU-R P.837-6 estimated 1-min values show greater error percentages. In order to get better approximation of local 1-min rain rate estimation, a novel method is proposed and it's efficiency have been compared with rainfall rate statistics obtained from nine different locations in the South

  16. Freezing Rain Diagnostic Study Over Eastern Canada Using the 5th Generation Canadian Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Bresson, É.; Paquin, D.; Laprise, R.; Theriault, J. M.; de Elía, R.

    2015-12-01

    Northeastern North America is often affected by freezing rain events during the cold season. They can have significant consequences (from road accidents, to severe power outages) despite their intensity and duration. The 1998 Ice Storm over Eastern Canada and Northeastern United States is an example of an extreme event with catastrophic consequences. A total of up to 150 mm of ice accumulated during 10 days were observed in some areas. This natural disaster has highlighted the need to better understand how such phenomena will evolve with future climate scenario. The goal is to investigate the feasibility of using regional climate modeling to diagnose the occurrence of freezing rain events over Quebec (Canada). To address this issue, we used the 5th generation of the Canadian Regional Climate Model (CRCM5), from 1979 to 2014. An empirical method (Bourgouin, 2000) developed to determine the type of winter precipitations was chosen to diagnose freezing rain events. The study focused in the Montreal area and the St. Lawrence River Valley (Quebec, Canada). The sensitivity of the model to horizontal resolution was explored by using three resolutions: 0.44°, 0.22° and 0.11°. In general, freezing rain was diagnosed consistently at all resolutions but the higher one (0.11°) produced more realistic results due to a better representation of the orography. Using the higher resolution, the results showed that the climatology of the freezing rain occurrence in the Montreal area is comparable to available observations. It also suggested that the role of the specific orography of the region with the St. Lawrence River Valley can impact the characteristics of freezing rain events in this area. Overall, this study will contribute to a better preparedness for such events in the future. High resolution regional climate simulations are essential to improve the reproduction of local scale orographically-forced phenomena.

  17. Rain Gauges Handbook

    SciTech Connect

    Bartholomew, M. J.

    2016-01-01

    To improve the quantitative description of precipitation processes in climate models, the Atmospheric Radiation Measurement (ARM) Climate Research Facility deployed rain gauges located near disdrometers (DISD and VDIS data streams). This handbook deals specifically with the rain gauges that make the observations for the RAIN data stream. Other precipitation observations are made by the surface meteorology instrument suite (i.e., MET data stream).

  18. A phase screen model for simulating numerically the propagation of a laser beam in rain

    SciTech Connect

    Lukin, I P; Rychkov, D S; Falits, A V; Lai, Kin S; Liu, Min R

    2009-09-30

    The method based on the generalisation of the phase screen method for a continuous random medium is proposed for simulating numerically the propagation of laser radiation in a turbulent atmosphere with precipitation. In the phase screen model for a discrete component of a heterogeneous 'air-rain droplet' medium, the amplitude screen describing the scattering of an optical field by discrete particles of the medium is replaced by an equivalent phase screen with a spectrum of the correlation function of the effective dielectric constant fluctuations that is similar to the spectrum of a discrete scattering component - water droplets in air. The 'turbulent' phase screen is constructed on the basis of the Kolmogorov model, while the 'rain' screen model utiises the exponential distribution of the number of rain drops with respect to their radii as a function of the rain intensity. Theresults of the numerical simulation are compared with the known theoretical estimates for a large-scale discrete scattering medium. (propagation of laser radiation in matter)

  19. Modeling of rain attenuation and site diversity predictions for tropical regions

    NASA Astrophysics Data System (ADS)

    Semire, F. A.; Mohd-Mokhtar, R.; Ismail, W.; Mohamad, N.; Mandeep, J. S.

    2015-03-01

    Presented in this paper is an empirical model for long-term rain attenuation prediction and statistical prediction of site diversity gain on a slant path. Rain attenuation prediction on a slant path is derived using data collected from tropical regions, and the formula proposed is based on Gaussian distribution. The proposed rain attenuation model shows a considerable reduction in prediction error in terms of standard deviation and root-mean-square (rms) error. The site diversity prediction model is derived as a function of site separation distance, frequency of operation, elevation angle and baseline orientation angle. The novelty of the model is the inclusion of low elevation angles and a high link frequency up to 70 GHz in the model derivation. The results of comparison with Hodge, Panagopoulos and Nagaraja empirical predictions show that the proposed model provides a better performance for site separation distance and elevation angle. The overall performance of the proposed site diversity model is good, and the percentage error is within the allowable error limit approved by International Telecommunication Union - Region (ITU-R).

  20. TRAC-MIP: Tropical Rain bands with an Annual cycle and Continent - Model Intercomparison Project.

    NASA Astrophysics Data System (ADS)

    Biasutti, Michela; Voigt, Aiko; Scheff, Jack; Zeppetello, Lucas Randall

    2016-04-01

    Understanding and modeling tropical rainfall has proven to be one of the most stubborn challenges in climate science. Tropical rainfall biases such as a double inter-tropical convergence zone (ITCZ) in the East Pacific have now persisted more than two decades despite the general improvements of climate models, and projections for the ITCZ and the monsoon systems remain uncertain in magnitude and sign. Progress in these areas can be fostered by a set of idealized experiments that target the dynamics of tropical rain band, as long as these simple experiments are properly integrated within a full hierarchy of model simulations. To this aim, we have designed the "Tropical Rain belts with an Annual cycle and Continent - Model Intercomparison Project." TRAC-MIP involves five experiments using idealized aquaplanet and land setups to explore the dynamics of tropical rainfall. By using interactive sea-surface temperatures and seasonally-varying insolation TRAC-MIP fills the gap between idealized aquaplanet simulations with prescribed SSTs and the fully-coupled realistic model simulations of CMIP5. TRAC-MIP includes the participation of 13 state-of-the art comprehensive climate models, and it also includes a simplified model that neglects cloud and water-vapor radiative feedbacks, thus allowing a more direct connection between the results from the TRAC-MIP comprehensive models and the theoretical studies of tropical rain belt dynamics. We will present preliminary results from the ensemble, aiming to examine the mechanisms controlling tropical precipitation in the context of forced variability. First and foremost, we are interested in the largest forced variation: the annual cycle. Second, we are interested in the response to key forcings of the future (greenhouse gases) and of the Holocene (insolation). We will draw out the similarities and the distinctions between oceanic and continental rain bands, study the ways in which the two interact with each other, and investigate

  1. After the Rain: Rain.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  2. A new model for rain scatter interference for coordination between Earth stations and terrestrial stations

    NASA Astrophysics Data System (ADS)

    Gibbins, Chris J.

    2005-08-01

    Scattering from rain is known to be a source of possible interference between communications systems sharing the same frequency bands. A new model has been developed for estimating the transmission loss due to bistatic rain scatter between an Earth station and a terrestrial station. This model has particular application in the process of coordination of Earth stations with terrestrial stations operating in the same frequency bands, whereby detailed interference studies are carried out only for stations within an area beyond which harmful interference may be considered negligible. The new model includes the Earth station elevation angle as an input parameter, together with the most recent information on rainfall rates and surface water vapor densities included in the recommendations of the International Telecommunications Union (ITU), and is more flexible yet neutral in its overall impact when applied to the process of coordination as defined in Appendix 7 of the ITU Radio Regulations.

  3. Forecasting rain events - Meteorological models or collective intelligence?

    NASA Astrophysics Data System (ADS)

    Arazy, Ofer; Halfon, Noam; Malkinson, Dan

    2015-04-01

    Collective intelligence is shared (or group) intelligence that emerges from the collective efforts of many individuals. Collective intelligence is the aggregate of individual contributions: from simple collective decision making to more sophisticated aggregations such as in crowdsourcing and peer-production systems. In particular, collective intelligence could be used in making predictions about future events, for example by using prediction markets to forecast election results, stock prices, or the outcomes of sport events. To date, there is little research regarding the use of collective intelligence for prediction of weather forecasting. The objective of this study is to investigate the extent to which collective intelligence could be utilized to accurately predict weather events, and in particular rainfall. Our analyses employ metrics of group intelligence, as well as compare the accuracy of groups' predictions against the predictions of the standard model used by the National Meteorological Services. We report on preliminary results from a study conducted over the 2013-2014 and 2014-2015 winters. We have built a web site that allows people to make predictions on precipitation levels on certain locations. During each competition participants were allowed to enter their precipitation forecasts (i.e. 'bets') at three locations and these locations changed between competitions. A precipitation competition was defined as a 48-96 hour period (depending on the expected weather conditions), bets were open 24-48 hours prior to the competition, and during betting period participants were allowed to change their bets with no limitation. In order to explore the effect of transparency, betting mechanisms varied across study's sites: full transparency (participants able to see each other's bets); partial transparency (participants see the group's average bet); and no transparency (no information of others' bets is made available). Several interesting findings emerged from

  4. Rain water transport and storage in a model sandy soil with hydrogel particle additives.

    PubMed

    Wei, Y; Durian, D J

    2014-10-01

    We study rain water infiltration and drainage in a dry model sandy soil with superabsorbent hydrogel particle additives by measuring the mass of retained water for non-ponding rainfall using a self-built 3D laboratory set-up. In the pure model sandy soil, the retained water curve measurements indicate that instead of a stable horizontal wetting front that grows downward uniformly, a narrow fingered flow forms under the top layer of water-saturated soil. This rain water channelization phenomenon not only further reduces the available rain water in the plant root zone, but also affects the efficiency of soil additives, such as superabsorbent hydrogel particles. Our studies show that the shape of the retained water curve for a soil packing with hydrogel particle additives strongly depends on the location and the concentration of the hydrogel particles in the model sandy soil. By carefully choosing the particle size and distribution methods, we may use the swollen hydrogel particles to modify the soil pore structure, to clog or extend the water channels in sandy soils, or to build water reservoirs in the plant root zone.

  5. Scale Dependence of Statistics of Spatially Averaged Rain Rate Seen in TOGA COARE Comparison with Predictions from a Stochastic Model

    NASA Technical Reports Server (NTRS)

    Kundu, Prasun K.; Bell, T. L.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    A characteristic feature of rainfall statistics is that they in general depend on the space and time scales over which rain data are averaged. As a part of an earlier effort to determine the sampling error of satellite rain averages, a space-time model of rainfall statistics was developed to describe the statistics of gridded rain observed in GATE. The model allows one to compute the second moment statistics of space- and time-averaged rain rate which can be fitted to satellite or rain gauge data to determine the four model parameters appearing in the precipitation spectrum - an overall strength parameter, a characteristic length separating the long and short wavelength regimes and a characteristic relaxation time for decay of the autocorrelation of the instantaneous local rain rate and a certain 'fractal' power law exponent. For area-averaged instantaneous rain rate, this exponent governs the power law dependence of these statistics on the averaging length scale $L$ predicted by the model in the limit of small $L$. In particular, the variance of rain rate averaged over an $L \\times L$ area exhibits a power law singularity as $L \\rightarrow 0$. In the present work the model is used to investigate how the statistics of area-averaged rain rate over the tropical Western Pacific measured with ship borne radar during TOGA COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmospheric Response Experiment) and gridded on a 2 km grid depends on the size of the spatial averaging scale. Good agreement is found between the data and predictions from the model over a wide range of averaging length scales.

  6. A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. Part 2: Theoretical development of a dynamic model and application to rain fade durations and tolerable control delays for fade countermeasures

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1987-01-01

    A dynamic rain attenuation prediction model is developed for use in obtaining the temporal characteristics, on time scales of minutes or hours, of satellite communication link availability. Analagous to the associated static rain attenuation model, which yields yearly attenuation predictions, this dynamic model is applicable at any location in the world that is characterized by the static rain attenuation statistics peculiar to the geometry of the satellite link and the rain statistics of the location. Such statistics are calculated by employing the formalism of Part I of this report. In fact, the dynamic model presented here is an extension of the static model and reduces to the static model in the appropriate limit. By assuming that rain attenuation is dynamically described by a first-order stochastic differential equation in time and that this random attenuation process is a Markov process, an expression for the associated transition probability is obtained by solving the related forward Kolmogorov equation. This transition probability is then used to obtain such temporal rain attenuation statistics as attenuation durations and allowable attenuation margins versus control system delay.

  7. Effect of wind-driven rain on deterioration of a tall building: Numerical modeling and field measurements

    NASA Astrophysics Data System (ADS)

    Tang, Wei

    Wind-driven rain is an important factor in determining the extent of calcareous stone erosion and the patterns of surface soiling on buildings. In this study, both numerical modeling and field measurements have been employed to investigate the effect of wind-driven rain on building walls. The work has been conducted at the Cathedral of Learning, a 42-story Indiana limestone building on the University of Pittsburgh campus in Pittsburgh, PA. The numerical method utilizes Computational Fluid Dynamics (CFD) techniques and comprises three steps: (a) using the Re-Normalization Group (RNG) k-epsilon model to calculate the airflow field around the building, (b) simulating raindrop trajectories in the flow field by solving the force balance equations, and (c) estimating driving rain fluxes on building walls by combining raindrop trajectory results and meteorological data. To validate the model, wind-driven rain fluxes have been measured at the Cathedral for a 21-month period. Comparison of model estimates and field measurements for 94 rain events show reasonably good agreement, suggesting that the numerical method is effective in predicting driving rain fluxes on building surfaces. Both model and measurement results show that wind-driven rain is strongly influenced by rainfall intensity, wind speed, wind direction, and building geometry. Qualitative comparisons of the observed soiling patterns with the modeled and measured driving rain fluxes show that white eroded areas on the building surfaces generally receive more driving rain than soiled but less eroded areas. The current soiling patterns are most likely due to the non-uniform distribution of wind-driven rain as a result of long-term trends in wind and rain that interact with the building. This work will enhance the understanding of processes involved in the erosion of buildings by providing a quantitative tool for studying the impact of wind-driven rain on building surfaces. This tool will be useful for the selection

  8. Analysis of a Mesoscale Model for Depicting Rain-on-Snow Flooding Events in Mountainous Terrain

    NASA Astrophysics Data System (ADS)

    Morehead, M. D.; Dawson, P.; Seyfried, M. S.

    2002-12-01

    Cold season rain-on-snow events are one of the major sources of flooding in the Pacific Northwest. Accurate modeling of the atmospheric fields forcing these events is leading to a better understanding of the atmospheric conditions behind these events and to better prediction of these floods. A mesoscale atmospheric model (RAMS) with nested grids is being used for high resolution simulations of winter precipitation and other climate variables in the Owyhee mountains of southwestern Idaho. The Reynolds Creek Experimental Watershed (RCEW) contains a dense array of meteorologic and hydrologic instrumentation with which to test the spatial and temporal hydrologic and atmospheric models. The large number of precipitation gauges in the RCEW cover a wide range of precipitation zones found in mountainous terrain. These gauges allow for a thorough assessment of the areal distribution and timing of modeled versus measured precipitation and temperature. A comparison of the modeled and measured data from two winter storms associated with rain-on-snow events shows close agreement in the spatial and temporal distributions of precipitation, temperature and other variables. The model correctly predicts the spatial distribution of precipitation and the temporal conversion from snow to rain-on-snow in the lower elevations of the watershed. The modeled precipitation is typically slightly lower than the measured values. Some of the high frequency (hourly) weather variability was not captured by the model, presumably due to lack of sufficient data in the initialization process. The longer term goal is to develop a tool for generating detailed weather information for winter time hydrologic studies including cold season flooding processes and to better understand the processes controlling winter flooding.

  9. Rooftop dew, fog and rain collection in southwest Morocco and predictive dew modeling using neural networks

    NASA Astrophysics Data System (ADS)

    Lekouch, Imad; Lekouch, Khalid; Muselli, Marc; Mongruel, Anne; Kabbachi, Belkacem; Beysens, Daniel

    2012-07-01

    SummaryTwo coastal sites were investigated in an arid region of southwest Morocco to determine the amount of dew, fog and rain that could be collected from rooftops for household use. Systematic measurements were performed in Mirleft (43 m asl, 200 m from the coast) for 1 year (May 1, 2007 to April 30, 2008) and in Id Ouasskssou (240 m asl, 8 km from the coast) for three summer months (July 1, 2007 to September 30, 2007). Dew water was collected using standard passive dew condensers and fog water by utilizing planar fog collectors. The wind flow was simulated on the rooftop to establish the location of the fog collector. At both sites, dew yields and, to a lesser extent, fog water yields, were found to be significant in comparison to rain events. Mirleft had 178 dew events (48.6% of the year, 18 ± 2 L m-2 cumulated amount) and 20 fog episodes (5.5% of the year, 1.4 L m-2 with uncertainty -0.2/+0.4 L m-2 cumulated amount), corresponding to almost 40% of the yearly rain contribution (31 rain events, 8.5% of the year, 49 ± 7 mm cumulated amount). At Id Ouasskssou there were 50 dew events (7.1 ± 0.3 L m-2, 54.3% frequency), 16 fog events (6.5 L m-2 with uncertainty -0.1/+1.8 L m-2, 17.4% frequency) and six rain events (16 ± 2 mm, 6.5% frequency). Meteorological data (air and dew point temperature and/or relative humidity, wind speed and wind direction, cloud cover) were recorded continuously at Mirleft to assess the influence of local meteorological conditions on dew and fog formation. Using the set of collected data, a new model for dew yield prediction based on artificial neural networks was developed and tested for the Mirleft site. This model was then extrapolated to 15 major cities in Morocco to assess their potential for dew water collection. It was found that the location of the cities with respect to the Atlas mountain chain, which controls the circulation of the humid marine air, is the main factor that influences dew production.

  10. Using snowboards and lysimeters to constrain snow model choices in a rain-snow transitional environment

    NASA Astrophysics Data System (ADS)

    Wayand, N. E.; Massmann, A.; Clark, M. P.; Lundquist, J. D.

    2015-12-01

    Physically based models of the hydrological cycle are critical for testing our understanding of the natural world and enabling forecasting of extreme events. Previous intercomparison studies (i.e. SNOWMIP I & II, PILPS) of existing snow models that vary in complexity have been hampered by multiple differences in model structure. Recent efforts to encompass multiple model hypothesizes into a single framework (i.e. the Structure for Understanding Multiple Modeling Alternatives [SUMMA] model), have provided the tools necessary for a more rigorous validation of process representation. However, there exist few snow observatories that measure sufficient physical states and fluxes to fully constrain the possible combinations within these multiple model frameworks. In practice, observations of bulk snow states, such as the snow water equivalent (SWE) or snow depth, are most commonly available. The downfall of calibrating a snow model using such single bulk variables can lead to parameter equanimity and compensatory errors, which ultimately impacts the skill of a model as a predictive tool. This study provides two examples of diagnosing modeled snow processes through novel error source identification. Simulations were performed at a recently upgraded (Oct. 2012) snow study site located at Snoqualmie Pass (917 m), in the Washington Cascades, USA. We focused on two physical processes, new snow accumulation and snowpack outflow during mid-winter rain-on-snow events, for their importance towards controlling runoff and flooding in this rain-snow transitional basin. Main results were: 1) modifying the snow model structure to match what was actually observed (i.e. a snow board), allowed the attribution of daily errors in model new snow accumulation to either partitioning, new snow density, or compaction. 2) Observed snow pit temperature profiles from infrared cameras and manual thermometers found that cold biases in the model snowpack temperature prior to rain-on-snow events could

  11. Rain-triggered lahar susceptibility using a shallow landslide and surface erosion model

    NASA Astrophysics Data System (ADS)

    Mead, Stuart; Magill, Christina; Hilton, James

    2016-11-01

    Lahars are mass flows containing variable concentrations of water and volcanic debris that can cause catastrophic impacts to life, livelihoods and infrastructure downstream from their volcanic origin. Accurate and quantitative information on lahar hazards are essential for reducing the impact of these events. Lahar hazard assessments often focus on the use of numeric or empirical models to describe flow behaviour and inundation areas, which rely on historic lahar events and expert elicitation to define model inputs. This results in qualitative or semi-quantitative estimates of hazard that do not account for the mechanics of lahar initiation or, in the case of rain-triggered lahars, the dependence of rainfall intensity and duration on initiation. Here we develop a method for calculating rain-triggered lahar susceptibility, defined as the occurrence probability of a particular lahar initial volume at a specific location. The model relies on terrain and deposit characteristics and a probabilistic measure of rainfall in the form of rainfall intensity-frequency-duration relationships. Results for a case study of the October 28, 1995 lahar at Mangatoetoenui stream, Ruapehu Volcano, New Zealand, indicate lahar volume is controlled by a characteristic timescale, relating the deposit depth H to the hydraulic diffusivity D0 in the ratio H2/D0. The timescale describes the transmission of positive pore pressures within the deposit, leading to shallow failure. As a consequence of this timescale, rainfall duration is the most important factor determining initial lahar sediment volume. Rainfall intensity plays a minor role, controlling the volume of water in the lahar mixture. This observation is consistent with power-law relationships used to determine lahar triggering rainfall thresholds. The rain-triggered lahar susceptibility approach developed here is anticipated to improve probabilistic lahar hazard assessments by providing quantitative, reproducible estimates of initial

  12. Modeling rain-driven overland flow: Empirical versus analytical friction terms in the shallow water approximation

    NASA Astrophysics Data System (ADS)

    Kirstetter, G.; Hu, J.; Delestre, O.; Darboux, F.; Lagrée, P.-Y.; Popinet, S.; Fullana, J. M.; Josserand, C.

    2016-05-01

    Modeling and simulating overland flow fed by rainfall is a common issue in watershed surface hydrology. Modelers have to choose among various friction models when defining their simulation framework. The purpose of this work is to compare the simulation quality for the Manning, Darcy-Weisbach, and Poiseuille friction models on the simple case of a constant rain on a thin experimental flume. Results show that the usual friction law of Manning is not suitable for this type of flow. The Poiseuille friction model gave the best results both on the flux at the outlet and the velocity and depth profile along the flume. The Darcy-Weisbach model shows good results for laminar flow. Additional testing should be carried out for turbulent cases.

  13. Extension of the prognostic model of sea surface temperature to rain-induced cool and fresh lenses

    NASA Astrophysics Data System (ADS)

    Bellenger, Hugo; Drushka, Kyla; Asher, William; Reverdin, Gilles; Katsumata, Masaki; Watanabe, Michio

    2017-01-01

    The Zeng and Beljaars (2005) sea surface temperature prognostic scheme, developed to represent diurnal warming, is extended to represent rain-induced freshening and cooling. Effects of rain on salinity and temperature in the molecular skin layer (first few hundred micrometers) and the near-surface turbulent layer (first few meters) are separately parameterized by taking into account rain-induced fluxes of sensible heat and freshwater, surface stress, and mixing induced by droplets penetrating the water surface. Numerical results from this scheme are compared to observational data from two field studies of near-surface ocean stratifications caused by rain, to surface drifter observations and to previous computations with an idealized ocean mixed layer model, demonstrating that the scheme produces temperature variations consistent with in situ observations and model results. It reproduces the dependency of salinity on wind and rainfall rate and the lifetime of fresh lenses. In addition, the scheme reproduces the observed lag between temperature and salinity minimum at low wind speed and is sensitive to the peak rain rate for a given amount of rain. Finally, a first assessment of the impact of these fresh lenses on ocean surface variability is given for the near-equatorial western Pacific. In particular, the variability due to the mean rain-induced cooling is comparable to the variability due to the diurnal warming so that they both impact large-scale horizontal surface temperature gradients. The present parameterization can be used in a variety of models to study the impact of rain-induced fresh and cool lenses at different spatial and temporal scales.

  14. Results of APL rain gauge network measurements in mid-Atlantic coast region and comparisons of distributions with CCIR models

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Gebo, Norman; Rowland, John

    1988-01-01

    In this effort are described cumulative rain rate distributions for a network of nine tipping bucket rain gauge systems located in the mid-Atlantic coast region in the vicinity of the NASA Wallops Flight Facility, Wallops Island, Virginia. The rain gauges are situated within a gridded region of dimensions of 47 km east-west by 70 km north-south. Distributions are presented for the individual site measurements and the network average for the year period June 1, 1986 through May 31, 1987. A previous six year average distribution derived from measurements at one of the site locations is also presented. Comparisons are given of the network average, the CCIR (International Radio Consultative Committee) climatic zone, and the CCIR functional model distributions, the latter of which approximates a log normal at the lower rain rate and a gamma function at the higher rates.

  15. Results of APL rain gauge network measurements in mid-Atlantic coast region and comparisons of distributions with CCIR models

    NASA Astrophysics Data System (ADS)

    Goldhirsh, Julius; Gebo, Norman; Rowland, John

    1988-08-01

    In this effort are described cumulative rain rate distributions for a network of nine tipping bucket rain gauge systems located in the mid-Atlantic coast region in the vicinity of the NASA Wallops Flight Facility, Wallops Island, Virginia. The rain gauges are situated within a gridded region of dimensions of 47 km east-west by 70 km north-south. Distributions are presented for the individual site measurements and the network average for the year period June 1, 1986 through May 31, 1987. A previous six year average distribution derived from measurements at one of the site locations is also presented. Comparisons are given of the network average, the CCIR (International Radio Consultative Committee) climatic zone, and the CCIR functional model distributions, the latter of which approximates a log normal at the lower rain rate and a gamma function at the higher rates.

  16. Estimation of Mesoscale Atmospheric Latent Heating Profiles from TRMM Rain Statistics Utilizing a Simple One-Dimensional Model

    NASA Technical Reports Server (NTRS)

    Iacovazzi, Robert A., Jr.; Prabhakara, C.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    In this study, a model is developed to estimate mesoscale-resolution atmospheric latent heating (ALH) profiles. It utilizes rain statistics deduced from Tropical Rainfall Measuring Mission (TRMM) data, and cloud vertical velocity profiles and regional surface thermodynamic climatologies derived from other available data sources. From several rain events observed over tropical ocean and land, ALH profiles retrieved by this model in convective rain regions reveal strong warming throughout most of the troposphere, while in stratiform rain regions they usually show slight cooling below the freezing level and significant warming above. The mesoscale-average, or total, ALH profiles reveal a dominant stratiform character, because stratiform rain areas are usually much larger than convective rain areas. Sensitivity tests of the model show that total ALH at a given tropospheric level varies by less than +/- 10 % when convective and stratiform rain rates and mesoscale fractional rain areas are perturbed individually by 1 15 %. This is also found when the non-uniform convective vertical velocity profiles are replaced by one that is uniform. Larger variability of the total ALH profiles arises when climatological ocean- and land-surface temperatures (water vapor mixing ratios) are independently perturbed by +/- 1.0 K (+/- 5 %) and +/- 5.0 K (+/- 15 %), respectively. At a given tropospheric level, such perturbations can cause a +/- 25 % variation of total ALH over ocean, and a factor-of-two sensitivity over land. This sensitivity is reduced substantially if perturbations of surface thermodynamic variables do not change surface relative humidity, or are not extended throughout the entire model evaporation layer. The ALH profiles retrieved in this study agree qualitatively with tropical total diabatic heating profiles deduced in earlier studies. Also, from January and July 1999 ALH-profile climatologies generated separately with TRMM Microwave Imager and Precipitation Radar rain

  17. Pre-rain green-up is ubiquitous across southern tropical Africa: implications for temporal niche separation and model representation.

    PubMed

    Ryan, Casey M; Williams, Mathew; Grace, John; Woollen, Emily; Lehmann, Caroline E R

    2017-01-01

    Tree phenology mediates land-atmosphere mass and energy exchange and is a determinant of ecosystem structure and function. In the dry tropics, including African savannas, many trees grow new leaves during the dry season - weeks or months before the rains typically start. This syndrome of pre-rain green-up has long been recognized at small scales, but the high spatial and interspecific variability in leaf phenology has precluded regional generalizations. We used remote sensing data to show that this precocious phenology is ubiquitous across the woodlands and savannas of southern tropical Africa. In 70% of the study area, green-up preceded rain onset by > 20 d (42% > 40 d). All the main vegetation formations exhibited pre-rain green-up, by as much as 53 ± 18 d (in the wet miombo). Green-up showed low interannual variability (SD between years = 11 d), and high spatial variability (> 100 d). These results are consistent with a high degree of local phenological adaptation, and an insolation trigger of green-up. Tree-tree competition and niche separation may explain the ubiquity of this precocious phenology. The ubiquity of pre-rain green-up described here challenges existing model representations and suggests resistance (but not necessarily resilience) to the delay in rain onset predicted under climate change.

  18. Evaluating the catching performance of aerodynamic rain gauges through field comparisons and CFD modelling

    NASA Astrophysics Data System (ADS)

    Pollock, Michael; Colli, Matteo; Stagnaro, Mattia; Lanza, Luca; Quinn, Paul; Dutton, Mark; O'Donnell, Greg; Wilkinson, Mark; Black, Andrew; O'Connell, Enda

    2016-04-01

    Accurate rainfall measurement is a fundamental requirement in a broad range of applications including flood risk and water resource management. The most widely used method of measuring rainfall is the rain gauge, which is often also considered to be the most accurate. In the context of hydrological modelling, measurements from rain gauges are interpolated to produce an areal representation, which forms an important input to drive hydrological models and calibrate rainfall radars. In each stage of this process another layer of uncertainty is introduced. The initial measurement errors are propagated through the chain, compounding the overall uncertainty. This study looks at the fundamental source of error, in the rainfall measurement itself; and specifically addresses the largest of these, the systematic 'wind-induced' error. Snowfall is outside the scope. The shape of a precipitation gauge significantly affects its collection efficiency (CE), with respect to a reference measurement. This is due to the airflow around the gauge, which causes a deflection in the trajectories of the raindrops near the gauge orifice. Computational Fluid-Dynamic (CFD) simulations are used to evaluate the time-averaged airflows realized around the EML ARG100, EML SBS500 and EML Kalyx-RG rain gauges, when impacted by wind. These gauges have a similar aerodynamic profile - a shape comparable to that of a champagne flute - and they are used globally. The funnel diameter of each gauge, respectively, is 252mm, 254mm and 127mm. The SBS500 is used by the UK Met Office and the Scottish Environmental Protection Agency. Terms of comparison are provided by the results obtained for standard rain gauge shapes manufactured by Casella and OTT which, respectively, have a uniform and a tapered cylindrical shape. The simulations were executed for five different wind speeds; 2, 5, 7, 10 and 18 ms-1. Results indicate that aerodynamic gauges have a different impact on the time-averaged airflow patterns

  19. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  20. Acid rain

    SciTech Connect

    Elsworth, S.

    1985-01-01

    This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

  1. A model for the beam-filling effect associated with the microwave retrieval of rain

    NASA Technical Reports Server (NTRS)

    Graves, Charles E.

    1993-01-01

    Estimating rain rate from environmental microwave emissions is hampered by several difficulties. One of these difficulties is known as the beam-filling effect. Beam filling is the systematic error introduced when the microwave radiometer's field of view is not filled with uniform rain. Beam filling can have dramatic effects on rain-rate estimation, causing rain rates to be underestimated by as much as a factor of 2. The present study derives an approximate expression for beam filling that provides, in principle, a way to estimate this effect. In addition, this study deals only with single-channel microwave rain estimation over the ocean. The final results reveal that beam filling is essentially determined by the freezing level, the mean fraction of the footprint raining, and the footprint-averaged rain rate. Also, the numerical results appear to agree with other empirical studies. Furthermore, the analysis brings to light an interesting connection with rain threshold techniques for estimating area-averaged rain rates.

  2. Aboveground Biomass Modeling from Field and LiDAR Data in Brazilian Amazon Tropical Rain Forest

    NASA Astrophysics Data System (ADS)

    Silva, C. A.; Hudak, A. T.; Vierling, L. A.; Keller, M. M.; Klauberg Silva, C. K.

    2015-12-01

    Tropical forests are an important component of global carbon stocks, but tropical forest responses to climate change are not sufficiently studied or understood. Among remote sensing technologies, airborne LiDAR (Light Detection and Ranging) may be best suited for quantifying tropical forest carbon stocks. Our objective was to estimate aboveground biomass (AGB) using airborne LiDAR and field plot data in Brazilian tropical rain forest. Forest attributes such as tree density, diameter at breast height, and heights were measured at a combination of square plots and linear transects (n=82) distributed across six different geographic zones in the Amazon. Using previously published allometric equations, tree AGB was computed and then summed to calculate total AGB at each sample plot. LiDAR-derived canopy structure metrics were also computed at each sample plot, and random forest regression modelling was applied to predict AGB from selected LiDAR metrics. The LiDAR-derived AGB model was assessed using the random forest explained variation, adjusted coefficient of determination (Adj. R²), root mean square error (RMSE, both absolute and relative) and BIAS (both absolute and relative). Our findings showed that the 99th percentile of height and height skewness were the best LiDAR metrics for AGB prediction. The AGB model using these two best predictors explained 59.59% of AGB variation, with an Adj. R² of 0.92, RMSE of 33.37 Mg/ha (20.28%), and bias of -0.69 (-0.42%). This study showed that LiDAR canopy structure metrics can be used to predict AGC stocks in Tropical Forest with acceptable precision and accuracy. Therefore, we conclude that there is good potential to monitor carbon sequestration in Brazilian Tropical Rain Forest using airborne LiDAR data, large field plots, and the random forest algorithm.

  3. The tropical rain belts with an annual cycle and a continent model intercomparison project: TRACMIP: TRACMIP

    SciTech Connect

    Voigt, Aiko; Biasutti, Michela; Scheff, Jacob; Bader, Jürgen; Bordoni, Simona; Codron, Francis; Dixon, Ross D.; Jonas, Jeffrey; Kang, Sarah M.; Klingaman, Nicholas P.; Leung, Ruby; Lu, Jian; Mapes, Brian; Maroon, Elizabeth A.; McDermid, Sonali; Park, Jong-yeon; Roehrig, Romain; Russell, Gary L.; Seo, Jeongbin; Toniazzo, Thomas; Wei, Ho-Hsuan; Yoshimori, Masakazu; Vargas Zeppetello, Lucas R.

    2016-12-02

    This paper introduces the Tropical Rain belts with an Annual cycle and a Continent Model Intercomparison Project (TRACMIP). TRACMIP studies the dynamics of tropical rain belts and their response to past and future radiative forcings through simulations with 13 comprehensive and one simplified atmosphere models coupled to a slab ocean and driven by seasonally-varying insolation. Five idealized experiments, two with an aquaplanet setup and three with a setup with an idealized tropical continent, fill the space between prescribed-SST aquaplanet simulations and realistic simulations provided by CMIP5/6. The simulations reproduce key features of the present-day climate and expected future climate change, including an annual-mean intertropical convergence zone (ITCZ) that is located north of the equator and Hadley cells and eddy-driven jets that are similar to the present-day climate. Quadrupling CO2 leads to a northward ITCZ shift and preferential warming in Northern high-latitudes. The simulations show interesting CO2-induced changes in the seasonal excursion of the ITCZ and indicate a possible state-dependence of climate sensitivity. The inclusion of an idealized continent modulates both the control climate and the response to increased CO2; for example it reduces the northward ITCZ shift associated with warming and, in some models, climate sensitivity. In response to eccentricity-driven seasonal insolation changes, seasonal changes in oceanic rainfall are best characterized as a meridional dipole, while seasonal continental rainfall changes tend to be symmetric about the equator. This survey illustrates TRACMIP’s potential to engender a deeper understanding of global and regional climate phenomena and to address pressing questions on past and future climate change.

  4. The tropical rain belts with an annual cycle and a continent model intercomparison project: TRACMIP

    DOE PAGES

    Voigt, Aiko; Biasutti, Michela; Scheff, Jacob; ...

    2016-11-16

    This paper introduces the Tropical Rain belts with an Annual cycle and a Continent Model Intercomparison Project (TRACMIP). TRACMIP studies the dynamics of tropical rain belts and their response to past and future radiative forcings through simulations with 13 comprehensive and one simplified atmosphere models coupled to a slab ocean and driven by seasonally-varying insolation. Five idealized experiments, two with an aquaplanet setup and three with a setup with an idealized tropical continent, fill the space between prescribed-SST aquaplanet simulations and realistic simulations provided by CMIP5/6. The simulations reproduce key features of the present-day climate and expected future climate change,more » including an annual-mean intertropical convergence zone (ITCZ) that is located north of the equator and Hadley cells and eddy-driven jets that are similar to the present-day climate. Quadrupling CO2 leads to a northward ITCZ shift and preferential warming in Northern high-latitudes. The simulations show interesting CO2-induced changes in the seasonal excursion of the ITCZ and indicate a possible state-dependence of climate sensitivity. The inclusion of an idealized continent modulates both the control climate and the response to increased CO2; for example it reduces the northward ITCZ shift associated with warming and, in some models, climate sensitivity. In response to eccentricity-driven seasonal insolation changes, seasonal changes in oceanic rainfall are best characterized as a meridional dipole, while seasonal continental rainfall changes tend to be symmetric about the equator. Finally, this survey illustrates TRACMIP’s potential to engender a deeper understanding of global and regional climate phenomena and to address pressing questions on past and future climate change.« less

  5. The tropical rain belts with an annual cycle and a continent model intercomparison project: TRACMIP

    SciTech Connect

    Voigt, Aiko; Biasutti, Michela; Scheff, Jacob; Bader, Jürgen; Bordoni, Simona; Codron, Francis; Dixon, Ross D.; Jonas, Jeffrey; Kang, Sarah M.; Klingaman, Nicholas P.; Leung, Ruby; Lu, Jian; Mapes, Brian; Maroon, Elizabeth A.; McDermid, Sonali; Park, Jong -yeon; Roehrig, Romain; Rose, Brian E. J.; Russell, Gary L.; Seo, Jeongbin; Toniazzo, Thomas; Wei, Ho -Hsuan; Yoshimori, Masakazu; Vargas Zeppetello, Lucas R.

    2016-11-16

    This paper introduces the Tropical Rain belts with an Annual cycle and a Continent Model Intercomparison Project (TRACMIP). TRACMIP studies the dynamics of tropical rain belts and their response to past and future radiative forcings through simulations with 13 comprehensive and one simplified atmosphere models coupled to a slab ocean and driven by seasonally-varying insolation. Five idealized experiments, two with an aquaplanet setup and three with a setup with an idealized tropical continent, fill the space between prescribed-SST aquaplanet simulations and realistic simulations provided by CMIP5/6. The simulations reproduce key features of the present-day climate and expected future climate change, including an annual-mean intertropical convergence zone (ITCZ) that is located north of the equator and Hadley cells and eddy-driven jets that are similar to the present-day climate. Quadrupling CO2 leads to a northward ITCZ shift and preferential warming in Northern high-latitudes. The simulations show interesting CO2-induced changes in the seasonal excursion of the ITCZ and indicate a possible state-dependence of climate sensitivity. The inclusion of an idealized continent modulates both the control climate and the response to increased CO2; for example it reduces the northward ITCZ shift associated with warming and, in some models, climate sensitivity. In response to eccentricity-driven seasonal insolation changes, seasonal changes in oceanic rainfall are best characterized as a meridional dipole, while seasonal continental rainfall changes tend to be symmetric about the equator. Finally, this survey illustrates TRACMIP’s potential to engender a deeper understanding of global and regional climate phenomena and to address pressing questions on past and future climate change.

  6. Electromagnetic Waves Attenuation due to Rain: A Prediction Model for Terrestrial or L.O.S SHF and EHF Radio Communication Links

    NASA Astrophysics Data System (ADS)

    Moupfouma, Fidèle

    2009-06-01

    Because of the interest raised for SHF and EHF radio communications, the attenuation of electromagnetic waves by rain will always constitute a major concern for telecommunication engineers and scientists. The rain attenuation prediction models exposed in literature calculate the attenuation related to a given rain rate or else to a given percentage of time. The new model proposed in this paper, predicts with a good accuracy the percentage of time for which any given rain attenuation will be exceeded on terrestrial SHF, EHF radiowaves links, provided the rain rate R001 (mm/h) that represents rain rate value exceeded for 0.01% of time in the locality of interest is available. R001 (mm/h) data being available for most of the localities across the world in ITU-R data base, we may conclude that this new model proposed here, can be broadly and successfully used.

  7. Acid Rain

    MedlinePlus

    ... EPA Is Doing Acid Rain Program Cross-State Air Pollution Rule Progress Reports Educational Resources Kid's Site for ... Monitoring National Atmospheric Deposition Program (NADP) Exit Interstate Air Pollution Transport Contact Us to ask a question, provide ...

  8. Measurement errors in tipping bucket rain gauges under different rainfall intensities and their implication to hydrologic models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurements from tipping bucket rain gauges (TBRs) consist of systematic and random errors as an effect of external factors, such as mechanical limitations, wind effects, evaporation losses, and rainfall intensity. Two different models of TBRs, viz. ISCO-674 and TR-525 (TexasInstr., Inc.), being us...

  9. Using Bayesian Belief Networks to model volcanic hazards interaction: an application for rain-triggered lahars

    NASA Astrophysics Data System (ADS)

    Tierz, Pablo; Odbert, Henry; Phillips, Jeremy; Woodhouse, Mark; Sandri, Laura; Selva, Jacopo; Marzocchi, Warner

    2016-04-01

    Quantification of volcanic hazards is a challenging task for modern volcanology. Assessing the large uncertainties involved in the hazard analysis requires the combination of volcanological data, physical and statistical models. This is a complex procedure even when taking into account only one type of volcanic hazard. However, volcanic systems are known to be multi-hazard environments where several hazardous phenomena (tephra fallout, Pyroclastic Density Currents -PDCs-, lahars, etc.) may occur whether simultaneous or sequentially. Bayesian Belief Networks (BBNs) are a flexible and powerful way of modelling uncertainty. They are statistical models that can merge information coming from data, physical models, other statistical models or expert knowledge into a unified probabilistic assessment. Therefore, they can be applied to model the interaction between different volcanic hazards in an efficient manner. In this work, we design and preliminarily parametrize a BBN with the aim of forecasting the occurrence and volume of rain-triggered lahars when considering: (1) input of pyroclastic material, in the form of tephra fallout and PDCs, over the catchments around the volcano; (2) remobilization of this material by antecedent lahar events. Input of fresh pyroclastic material can be modelled through a combination of physical models (e.g. advection-diffusion models for tephra fallout such as HAZMAP and shallow-layer continuum models for PDCs such as Titan2D) and uncertainty quantification techniques, while the remobilization efficiency can be constrained from datasets of lahar observations at different volcanoes. The applications of this kind of probabilistic multi-hazard approach can range from real-time forecasting of lahar activity to calibration of physical or statistical models (e.g. emulators) for long-term volcanic hazard assessment.

  10. Modeled dosage-response relationship on the net photosynthetic rate for the sensitivity to acid rain of 21 plant species.

    PubMed

    Deng, Shihuai; Gou, Shuzhen; Sun, Baiye; Lv, Wenlin; Li, Yuanwei; Peng, Hong; Xiao, Hong; Yang, Gang; Wang, Yingjun

    2012-08-01

    This study investigated the sensitivity of plant species to acid rain based on the modeled dosage-response relationship on the net photosynthetic rate (P (N)) of 21 types of plant species, subjected to the exposure of simulated acid rain (SAR) for 5 times during a period of 50 days. Variable responses of P (N) to SAR occurred depending on the type of plant. A majority (13 species) of the dosage-response relationship could be described by an S-shaped curve and be fitted with the Boltzmann model. Model fitting allowed quantitative evaluation of the dosage-response relationship and an accurate estimation of the EC(10), termed as the pH of the acid rain resulting in a P (N) 10 % lower than the reference value. The top 9 species (Camellia sasanqua, Cinnamomum camphora, etc. EC(10) ≤ 3.0) are highly endurable to very acid rain. The rare, relict plant Metasequoia glyptostroboides was the most sensitive species (EC(10) = 5.1) recommended for protection.

  11. Rain Rate Statistics in Southern New Mexico

    NASA Technical Reports Server (NTRS)

    Paulic, Frank J., Jr.; Horan, Stephen

    1997-01-01

    The methodology used in determining empirical rain-rate distributions for Southern New Mexico in the vicinity of White Sands APT site is discussed. The hardware and the software developed to extract rain rate from the rain accumulation data collected at White Sands APT site are described. The accuracy of Crane's Global Model for rain rate predictions is analyzed.

  12. Acid Rain

    USGS Publications Warehouse

    Bricker, Owen P.; Rice, Karen C.

    1995-01-01

    Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

  13. Superposition of the Neyman-Scott Rectangular Pulses Model and the Poisson White Noise Model for the Representation of Tropical Rain Rates

    NASA Astrophysics Data System (ADS)

    Morrissey, M. L.

    2009-12-01

    A point process model for tropical rain rates is developed through the derivation of the third moment expression for a combined point process model. The model is a superposition of a Neyman-Scott rectangular pulse model and a Poisson white noise process model. The model is scalable in the temporal dimension. The derivation of the third moment for this model allows the inclusion of the skewness parameter which is necessary to adequately represent rainfall intensity. Analysis of the model fit to tropical tipping bucket raingauge data ranging in temporal scale from 5 minutes to one day indicates that it can adequately produce synthesized rainfall having the statistical characteristics of rain rate over the range of scales tested. Of special interest is the model’s capability to accurately preserve the probability of extreme tropical rain rates at different scales. In addition to various hydrological applications, the model also has many potential uses in the field of meteorology, such as the study and development of radar rain rate algorithms for the tropics which need to parameterized attenuation due to heavy rain.

  14. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    PubMed

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (p<0.001) higher removal of nitrate was observed in the biphasic (42-63%) compared to the monophasic rain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (p<0.001), achieving up to 87% removal at a treatment C/N ratio of 2.0. This study demonstrates the importance of retention time, environmental conditions (i.e. saturated/unsaturated conditions), and availability of C substrate for bioremediation of pollutants, especially nitrates, in rain gardens.

  15. Improvement of Tidal Analysis Results by a Priori Rain Fall Modelling at the Vienna and Membach stations

    NASA Astrophysics Data System (ADS)

    Meurers, B.; van Camp, M.; Petermans, T.

    2005-12-01

    We investigate how far tidal analysis results can be improved when a rain fall admittance model is applied on the superconducting gravity (SG) data. For that purpose both Vienna and Membach data have been analysed with and without a priori rain fall correction. In Membach the residual drop for most events (80%) can be explained by the rain water load, while in Vienna only 50% of all events fit the model in detail. In the other cases the Newtonian effect of vertical air mass redistribution (vertical density variation without air pressure change), predominantly connected with high vertical convection activity, e.g. thunderstorms, plays an essential role: short-term atmospheric signals show up steep gravity residual decreases of a few nms-2 within 10 - 60 min, well correlated with outdoor air temperature in most cases. However, even in those cases the water load model is able to explain the dominating part of the residual drop especially during heavy rain fall. In Vienna more than 110 events have been detected over 10 years. 84% of them are associated with heavy rain starting at or up to 10 min later than the residual drop while the rest (16%) shows no or only little rainfall. The magnitude of the gravity drop depends on the total amount of rainfall accumulated during the meteorological event. Step like signals deteriorate the frequency spectrum estimates. This even holds for tidal analysis. As the drops are of physical origin, they should not be eliminated blindly but corrected using water load modeling constrained by high temporal resolution (1 min) rain data. 3D modeling of the water mass load due to a rain event is based on the following assumptions: (1) Rain water intrudes into the uppermost soil layer (close to the topography surface) and remains there at least until rain has stopped. This is justified for a period of some hours after the rainfall as evapotranspiration is not yet effective. (2) No run-off except of sealed areas or building roofs, where water can

  16. Diabatic forcing and initialization with assimilation of cloud and rain water in a forecast model: Methodology

    NASA Technical Reports Server (NTRS)

    Raymond, William H.; Olson, William S.; Callan, Geary

    1990-01-01

    The focus of this part of the investigation is to find one or more general modeling techniques that will help reduce the time taken by numerical forecast models to initiate or spin-up precipitation processes and enhance storm intensity. If the conventional data base could explain the atmospheric mesoscale flow in detail, then much of our problem would be eliminated. But the data base is primarily synoptic scale, requiring that a solution must be sought either in nonconventional data, in methods to initialize mesoscale circulations, or in ways of retaining between forecasts the model generated mesoscale dynamics and precipitation fields. All three methods are investigated. The initialization and assimilation of explicit cloud and rainwater quantities computed from conservation equations in a mesoscale regional model are examined. The physical processes include condensation, evaporation, autoconversion, accretion, and the removal of rainwater by fallout. The question of how to initialize the explicit liquid water calculations in numerical models and how to retain information about precipitation processes during the 4-D assimilation cycle are important issues that are addressed. The explicit cloud calculations were purposely kept simple so that different initialization techniques can be easily and economically tested. Precipitation spin-up processes associated with three different types of weather phenomena are examined. Our findings show that diabatic initialization, or diabatic initialization in combination with a new diabatic forcing procedure, work effectively to enhance the spin-up of precipitation in a mesoscale numerical weather prediction forecast. Also, the retention of cloud and rain water during the analysis phase of the 4-D data assimilation procedure is shown to be valuable. Without detailed observations, the vertical placement of the diabatic heating remains a critical problem.

  17. Assessment of prediction and predictability of short rains over equatorial East Africa using a multi-model ensemble

    NASA Astrophysics Data System (ADS)

    Bahaga, T. K.; Kucharski, F.; Tsidu, G. Mengistu; Yang, Hongwei

    2016-02-01

    In this study, the performance of dynamical seasonal forecast systems is evaluated for the prediction of short rain anomalies over equatorial East Africa. The evaluation is based on observational datasets and the Asia-Pacific Climate Center (APCC) Ocean-Atmosphere coupled multi-model ensemble (MME) retrospective forecasts (hindcasts). These forecast systems have different hindcast periods; here, we have selected common years from 1982 to 2005. The ensembles of individual models and their MME mean are evaluated. Hindcasts initialized on the 1st of August from each year alone are considered, as these are the most relevant to short rain predictions. The coupled climate model ensemble reproduces the spatial distribution of mean September-October-November (SON) rainfall and seasonal climate variations over equatorial East Africa with further improvement in MME mean. Individual coupled models and MME mean also show statistically significant skill in forecasting sea surface temperatures anomalies (SSTAs) over the western and eastern parts of the equatorial Indian Ocean, giving significant correlation at 99 % confidence level for Indian Ocean dipole (IOD). Moreover, five out of ten coupled models and MME mean show statistically significant skill in predicting equatorial East Africa short rains. The fidelity of hindcasts is further measured by anomaly correlation coefficient (ACC) and four models as well as MME mean show significant skill over East Africa. It is shown that the reproduction of the observed variability in the East African region is mainly due to a realistic relationship of East African rainfall with the Indian Ocean dipole. Overall, the skill of the dynamical models is attributed to the fact that slowly evolving SSTs are the primary source of predictability and to the fact that coupled climate models produce skillful predictions of SON SST anomalies over the tropical Indian Ocean. This information opens the possibility of using readily available seasonal

  18. Modelling Hydrologic Processes in the Mekong River Basin Using a Distributed Model Driven by Satellite Precipitation and Rain Gauge Observations.

    PubMed

    Wang, Wei; Lu, Hui; Yang, Dawen; Sothea, Khem; Jiao, Yang; Gao, Bin; Peng, Xueting; Pang, Zhiguo

    2016-01-01

    The Mekong River is the most important river in Southeast Asia. It has increasingly suffered from water-related problems due to economic development, population growth and climate change in the surrounding areas. In this study, we built a distributed Geomorphology-Based Hydrological Model (GBHM) of the Mekong River using remote sensing data and other publicly available data. Two numerical experiments were conducted using different rainfall data sets as model inputs. The data sets included rain gauge data from the Mekong River Commission (MRC) and remote sensing rainfall data from the Tropic Rainfall Measurement Mission (TRMM 3B42V7). Model calibration and validation were conducted for the two rainfall data sets. Compared to the observed discharge, both the gauge simulation and TRMM simulation performed well during the calibration period (1998-2001). However, the performance of the gauge simulation was worse than that of the TRMM simulation during the validation period (2002-2012). The TRMM simulation is more stable and reliable at different scales. Moreover, the calibration period was changed to 2, 4, and 8 years to test the impact of the calibration period length on the two simulations. The results suggest that longer calibration periods improved the GBHM performance during validation periods. In addition, the TRMM simulation is more stable and less sensitive to the calibration period length than is the gauge simulation. Further analysis reveals that the uneven distribution of rain gauges makes the input rainfall data less representative and more heterogeneous, worsening the simulation performance. Our results indicate that remotely sensed rainfall data may be more suitable for driving distributed hydrologic models, especially in basins with poor data quality or limited gauge availability.

  19. Areal rainfall estimation using moving cars as rain gauges - modeling study and laboratory experiment

    NASA Astrophysics Data System (ADS)

    Rabiei, E.; Haberlandt, U.; Sester, M.; Fitzner, D.

    2012-04-01

    Areal rainfall estimation is still one of the concerns in hydrological analyses. Low density of the conventional rainfall measurement devices as well as the errors in radar data developed the new idea of using moving cars, called raincars, as a possible new source for measuring rainfall. This idea is easily technically feasible if the cars are provided with GPS and a small memory chip for recording the coordinates, car speed and data from the sensors, either for the frequency measurement of the wipers or the optical sensors on cars. According to the modeling study, which is done on the Bode catchment in Germany, a high number of possibly inaccurate sensors, raincars, provide more reliable areal rainfall estimation than a lower number of highly accurate, stationary sensors. In this study, data for the stationary gauges and the cars are extracted from the radar data. A valid relationship between wiper frequency and rainfall with a known error is assumed where the radar data is considered as the reference. Areal precipitation is estimated by different interpolation techniques, ordinary kriging for the stationary stations and indicator kriging for the cars. The results are then compared and evaluated with the reference, radar. After proving the feasibility of the hypothesis in the modeling study, field and laboratory experiment have been arranged. A certain number of cars has been equipped with sensors and in the laboratory, to produce the rainfall as close as possible to nature, sprinkler irrigation system has been designed for producing different rain intensities, from 1 mm/hr to 55 mm/hr. Here, we can develop an empirical approach for the relationship between the wiper frequency and rainfall intensity as well as for the optical sensors on the cars under different rainfall intensities.

  20. Geostatistical upscaling of rain gauge data to support uncertainty analysis of lumped urban hydrological models

    NASA Astrophysics Data System (ADS)

    Muthusamy, Manoranjan; Schellart, Alma; Tait, Simon; Heuvelink, Gerard B. M.

    2017-02-01

    In this study we develop a method to estimate the spatially averaged rainfall intensity together with associated level of uncertainty using geostatistical upscaling. Rainfall data collected from a cluster of eight paired rain gauges in a 400 m × 200 m urban catchment are used in combination with spatial stochastic simulation to obtain optimal predictions of the spatially averaged rainfall intensity at any point in time within the urban catchment. The uncertainty in the prediction of catchment average rainfall intensity is obtained for multiple combinations of intensity ranges and temporal averaging intervals. The two main challenges addressed in this study are scarcity of rainfall measurement locations and non-normality of rainfall data, both of which need to be considered when adopting a geostatistical approach. Scarcity of measurement points is dealt with by pooling sample variograms of repeated rainfall measurements with similar characteristics. Normality of rainfall data is achieved through the use of normal score transformation. Geostatistical models in the form of variograms are derived for transformed rainfall intensity. Next spatial stochastic simulation which is robust to nonlinear data transformation is applied to produce realisations of rainfall fields. These realisations in transformed space are first back-transformed and next spatially aggregated to derive a random sample of the spatially averaged rainfall intensity. Results show that the prediction uncertainty comes mainly from two sources: spatial variability of rainfall and measurement error. At smaller temporal averaging intervals both these effects are high, resulting in a relatively high uncertainty in prediction. With longer temporal averaging intervals the uncertainty becomes lower due to stronger spatial correlation of rainfall data and relatively smaller measurement error. Results also show that the measurement error increases with decreasing rainfall intensity resulting in a higher

  1. Rain-on-snow events over North America based on two Canadian regional climate models

    NASA Astrophysics Data System (ADS)

    Il Jeong, Dae; Sushama, Laxmi

    2017-03-01

    This study evaluates projected changes to rain-on-snow (ROS) characteristics (i.e., frequency, rainfall amount, and runoff) for the future 2041-2070 period with respect to the current 1976-2005 period over North America using six simulations, based on two Canadian RCMs, driven by two driving GCMs for RCP4.5 and 8.5 emission pathways. Prior to assessing projected changes, the two RCMs are evaluated by comparing ERA-Interim driven RCM simulations with available observations, and results indicate that both models reproduce reasonably well the observed spatial patterns of ROS event frequency and other related features. Analysis of current and future simulations suggest general increases in ROS characteristics during the November-March period for most regions of Canada and for northwestern US for the future period, due to an increase in the rainfall frequency with warmer air temperatures in future. Future ROS runoff is often projected to increase more than future ROS rainfall amounts, particularly for northeastern North America, during snowmelt months, as ROS events usually accelerate snowmelt. The simulations show that ROS event is a primary flood generating mechanism over most of Canada and north-western and -central US for the January-May period for the current period and this is projected to continue in the future period. More focused analysis over selected basins shows decreases in future spring runoff due to decreases in both snow cover and ROS runoff. The above results highlight the need to take into consideration ROS events in water resources management adaptation strategies for future climate.

  2. Regional modeling sensitivity experiments for interpreting the UK Winter 2013-2014 extreme rain

    NASA Astrophysics Data System (ADS)

    Omrani, H.; Vautard, R.; Schaller, N.; Allen, M. R.

    2015-12-01

    During the winter 2013/2014, the UK saw heavy rainfalls associated with a succession of storms reaching Southern England causing widespread flooding, power cuts and major disruptions to transport. The January precipitation set a record for several rain gauge stations in Southern England. The aim of this study is to evaluate the contribution of the anthropogenic climate change, represented by a modification of the sea surface temperature (SST) on the January precipitation. For that, we conducted a sensitivity experiment by running a set of 108 four-months simulations using WRF model with 9 different physics and 12 different SST fields; 9 for the factual world and 99 for the counter-factual world. A spectral nudging technique was used here to ensure a same atmospheric circulation patterns for all the simulations. Therefore, only the thermodynamic effect is considered here. The analysis is focused on January precipitation over the southern England. Results show for 0,5°C SST difference over the Northern Atlantic, the precipitation in the factual simulations is between 0,4 and 8% higher than the precipitation in the counter-factual simulations depending on the physic. A validation test shows that this value is closer to 8% for the "best physic" simulation. It also show a strong spatial variability where in some region the precipitation is higher in the counter-factual world compared the factual world. Finally, a backward trajectories were calculated to evaluate the sensitivity of the moisture sources and air mass trajectories to the SST in the factual and the counter-factual world.

  3. An Iron-Rain Model for Core Formation on Asteroid 4 Vesta

    NASA Technical Reports Server (NTRS)

    Kiefer, Walter S.; Mittlefehldt, David W.

    2016-01-01

    Asteroid 4 Vesta is differentiated into a crust, mantle, and core, as demonstrated by studies of the eucrite and diogenite meteorites and by data from NASA's Dawn spacecraft. Most models for the differentiation and thermal evolution of Vesta assume that the metal phase completely melts within 20 degrees of the eutectic temperature, well before the onset of silicate melting. In such a model, core formation initially happens by Darcy flow, but this is an inefficient process for liquid metal and solid silicate. However, the likely chemical composition of Vesta, similar to H chondrites with perhaps some CM or CV chondrite, has 13-16 weight percent S. For such compositions, metal-sulfide melting will not be complete until a temperature of at least 1350 degrees Centigrade. The silicate solidus for Vesta's composition is between 1100 and 1150 degrees Centigrade, and thus metal and silicate melting must have substantially overlapped in time on Vesta. In this chemically and physically more likely view of Vesta's evolution, metal sulfide drops will sink by Stokes flow through the partially molten silicate magma ocean in a process that can be envisioned as "iron rain". Measurements of eucrites show that moderately siderophile elements such as Ni, Mo, and W reached chemical equilibrium between the metal and silicate phases, which is an important test for any Vesta differentiation model. The equilibration time is a function of the initial metal grain size, which we take to be 25-45 microns based on recent measurements of H6 chondrites. For these sizes and reasonable silicate magma viscosities, equilibration occurs after a fall distance of just a few meters through the magma ocean. Although metal drops may grow in size by merger with other drops, which increases their settling velocities and decreases the total core formation time, the short equilibration distance ensures that the moderately siderophile elements will reach chemical equilibrium between metal and silicate before

  4. A Cold Rain-on-Snow Event in a Canadian Rockies Alpine Catchment: Characteristics and Modelling

    NASA Astrophysics Data System (ADS)

    Pomeroy, J. W.; Fang, X.; Marks, D. G.

    2014-12-01

    Over three days in late June 2013, 250 mm of precipitation fell on the partially snow-covered and heavily instrumented Marmot Creek Research Basin, Canadian Rockies, causing the largest recorded flood in the region, the destruction of most gauging stations in the research basin and the most expensive natural disaster in Canadian history. Precipitation was remarkable in that similar depths fell at all elevations from forest-grassland valley bottom to mid-elevation montane forest to alpine ridge-top and started with relatively warm conditions even at high elevations (6 oC), turning to snowfall at the highest elevations towards the end of the event. Snowfall in the alpine zone of the basin is highly redistributed by wind and forms deep drifts on lee slopes and in tree-line forests. These snowdrifts persist into summer and form a critical water supply for the creek. Snow surveys six days before and one day after the event show alpine snowdrift water equivalent declining from 350 to 150 mm and snow-covered area declining from 97% to 55% The snowpack ablation of 120 mm during the heavy precipitation period enhanced water delivery to alpine surfaces from rainfall by 50%. The event was simulated using the modular, physically-based Cold Regions Hydrological Model which was set up here to include a blowing snow model and infiltration to frozen soil model coupled to the SNOBAL energy balance snowmelt model. The results show substantially slower snowmelt rates during the rain-on-snow (ROS) event than before or after the ROS. ROS was characterized by greatly reduced solar irradiance, which was not compensated for by increased net longwave radiation, advected heat from rainfall and small but consistently downward fluxes of sensible and latent heat. Turbulent fluxes did not drive melt as has been suggested for more temperate ROS melts and energy sources can be ranked as K*>L*>Qa>Qh>Qe>>Qg. Nevertheless the combination of rainfall, snowmelt and frozen soils caused alpine

  5. Rain rate intensity model for communication link design across the Indian region

    NASA Astrophysics Data System (ADS)

    Kilaru, Aravind; Kotamraju, Sarat K.; Avlonitis, Nicholas; Sri Kavya, K. Ch.

    2016-07-01

    A study on rain statistical parameters such as one minute rain intensity, possible number of minute occurrences with respective percentage of time in a year has been evaluated for the purpose of communication link design at Ka, Q, V bands as well as at Free-Space Optical communication links (FSO). To understand possible outage period of a communication links due to rainfall and to investigate rainfall pattern, Automatic Weather Station (AWS) rainfall data is analysed due its ample presence across India. The climates of the examined AWS regions vary from desert to cold climate, heavy rainfall to variable rainfall regions, cyclone effective regions, mountain and coastal regions. In this way a complete and unbiased picture of the rainfall statistics for Indian region is evaluated. The analysed AWS data gives insight into yearly accumulated rainfall, maximum hourly accumulated rainfall, mean hourly accumulated rainfall, number of rainy days and number of rainy hours from 668 AWS locations. Using probability density function the one minute rainfall measurements at KL University is integrated with AWS measurements for estimating number of rain occurrences in terms of one minute rain intensity for annual rainfall accumulated between 100 mm and 5000 mm to give an insight into possible one minute accumulation pattern in an hour for comprehensive analysis of rainfall influence on a communication link for design engineers. So that low availability communications links at higher frequencies can be transformed into a reliable and economically feasible communication links for implementing High Throughput Services (HTS).

  6. Evaluation of Cloud-resolving and Limited Area Model Intercomparison Simulations using TWP-ICE Observations. Part 2: Rain Microphysics

    SciTech Connect

    Varble, Adam; Zipser, Edward J.; Fridlind, Ann; Zhu, Ping; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; Shipway, Ben; Williams, Christopher R.

    2014-12-27

    Ten 3D cloud-resolving model (CRM) simulations and four 3D limited area model (LAM) simulations of an intense mesoscale convective system observed on January 23-24, 2006 during the Tropical Warm Pool – International Cloud Experiment (TWP-ICE) are compared with each other and with observations and retrievals from a scanning polarimetric radar, co-located UHF and VHF vertical profilers, and a Joss-Waldvogel disdrometer in an attempt to explain published results showing a low bias in simulated stratiform rainfall. Despite different forcing methodologies, similar precipitation microphysics errors appear in CRMs and LAMs with differences that depend on the details of the bulk microphysics scheme used. One-moment schemes produce too many small raindrops, which biases Doppler velocities low, but produces rain water contents (RWCs) that are similar to observed. Two-moment rain schemes with a gamma shape parameter (μ) of 0 produce excessive size sorting, which leads to larger Doppler velocities than those produced in one-moment schemes, but lower RWCs than observed. Two moment schemes also produce a convective median volume diameter distribution that is too broad relative to observations and thus, may have issues balancing raindrop formation, collision coalescence, and raindrop breakup. Assuming a μ of 2.5 rather than 0 for the raindrop size distribution improves one-moment scheme biases, and allowing μ to have values greater than 0 may improve two-moment schemes. Under-predicted stratiform rain rates are associated with under-predicted ice water contents at the melting level rather than excessive rain evaporation, in turn likely associated with convective detrainment that is too high in the troposphere and mesoscale circulations that are too weak. In addition to stronger convective updrafts than observed, limited domain size prevents a large, well-developed stratiform region from developing in CRMs, while a dry bias in ECMWF analyses does the same to the LAMs.

  7. Land-Ocean Difference of the Warm Rain Formation Process in Satellite Observations, Ground-Based Observations, and Model Simulations

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Suzuki, K.; Stephens, G. L.

    2015-12-01

    This study examines the difference in the warm rain formation process between over land and over ocean using a combination of CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) observations. Previous studies (Nakajima et al. 2010; Suzuki et al. 2010) have devised a novel methodology for combining the CloudSat and MODIS satellite observations to investigate the microphysical processes. The statistics constructed with the methodology, referred to as the Contoured Frequency by Optical Depth Diagram (CFODD), provides a lifecycle view of warm clouds. Following the previous studies, we conduct detailed analyses of CFODD with a particular focus on comparisons between land and ocean. Our result shows that the coalescence process starts faster in the oceanic warm clouds than continental warm clouds. Also, oceanic clouds tend to produce more drizzle than continental clouds. Moreover, it is found that the difference between oceanic and continental cloud-to-precipitation process can be explained by different environmental conditions. For example, the cloud-to-precipitation processes in continental clouds are more similar to those in oceanic clouds over unstable environments than those over stable environments. Furthermore, ground-based measurement data obtained from Atmospheric Radiation Measurement (ARM) data and a cloud model simulation are analyzed to test how vertical velocity affects the warm rain formation process. Our result suggests that although the intensities of convective updrafts in warm clouds have been paid less attention, intensities of convective updrafts play a critical role in the warm rain formation process.

  8. Acid Rain

    USGS Publications Warehouse

    Bricker, Owen P.; Rice, Karen C.

    1993-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  9. Acid Rain

    USGS Publications Warehouse

    Bricker, Owen P.; Rice, Karen C.; Dietrich, W.E.; Sposito, Garrison

    1997-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  10. The Acid Rain Game.

    ERIC Educational Resources Information Center

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  11. Evaluating a slope-stability model for shallow rain-induced landslides using gage and satellite data

    USGS Publications Warehouse

    Yatheendradas, S.; Kirschbaum, D.; Baum, Rex L.; Godt, Jonathan W.

    2014-01-01

    Improving prediction of landslide early warning systems requires accurate estimation of the conditions that trigger slope failures. This study tested a slope-stability model for shallow rainfall-induced landslides by utilizing rainfall information from gauge and satellite records. We used the TRIGRS model (Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis) for simulating the evolution of the factor of safety due to rainfall infiltration. Using a spatial subset of a well-characterized digital landscape from an earlier study, we considered shallow failure on a slope adjoining an urban transportation roadway near the Seattle area in Washington, USA.We ran the TRIGRS model using high-quality rain gage and satellite-based rainfall data from the Tropical Rainfall Measuring Mission (TRMM). Preliminary results with parameterized soil depth values suggest that the steeper slope values in this spatial domain have factor of safety values that are extremely close to the failure limit within an extremely narrow range of values, providing multiple false alarms. When the soil depths were constrained using a back analysis procedure to ensure that slopes were stable under initial condtions, the model accurately predicted the timing and location of the landslide observation without false alarms over time for gage rain data. The TRMM satellite rainfall data did not show adequately retreived rainfall peak magnitudes and accumulation over the study period, and as a result failed to predict the landslide event. These preliminary results indicate that more accurate and higher-resolution rain data (e.g., the upcoming Global Precipitation Measurement (GPM) mission) are required to provide accurate and reliable landslide predictions in ungaged basins.

  12. Compilation and Analysis of 20 and 30 GHz Rain Fade Events at the ACTS NASA Ground Station: Statistics and Model Assessment

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1996-01-01

    The purpose of the propagation studies within the ACTS Project Office is to acquire 20 and 30 GHz rain fade statistics using the ACTS beacon links received at the NGS (NASA Ground Station) in Cleveland. Other than the raw, statistically unprocessed rain fade events that occur in real time, relevant rain fade statistics derived from such events are the cumulative rain fade statistics as well as fade duration statistics (beyond given fade thresholds) over monthly and yearly time intervals. Concurrent with the data logging exercise, monthly maximum rainfall levels recorded at the US Weather Service at Hopkins Airport are appended to the database to facilitate comparison of observed fade statistics with those predicted by the ACTS Rain Attenuation Model. Also, the raw fade data will be in a format, complete with documentation, for use by other investigators who require realistic fade event evolution in time for simulation purposes or further analysis for comparisons with other rain fade prediction models, etc. The raw time series data from the 20 and 30 GHz beacon signals is purged of non relevant data intervals where no rain fading has occurred. All other data intervals which contain rain fade events are archived with the accompanying time stamps. The definition of just what constitutes a rain fade event will be discussed later. The archived data serves two purposes. First, all rain fade event data is recombined into a contiguous data series every month and every year; this will represent an uninterrupted record of the actual (i.e., not statistically processed) temporal evolution of rain fade at 20 and 30 GHz at the location of the NGS. The second purpose of the data in such a format is to enable a statistical analysis of prevailing propagation parameters such as cumulative distributions of attenuation on a monthly and yearly basis as well as fade duration probabilities below given fade thresholds, also on a monthly and yearly basis. In addition, various subsidiary

  13. Acid rain

    SciTech Connect

    Not Available

    1984-06-01

    An overview is presented of acid rain and the problems it causes to the environment worldwide. The acidification of lakes and streams is having a dramatic effect on aquatic life. Aluminum, present in virtually all forest soils, leaches out readily under acid conditions and interferes with the gills of all fish, some more seriously than others. There is evidence of major damage to forests in European countries. In the US, the most severe forest damage appears to be in New England, New York's Adirondacks, and the central Appalachians. This small region is part of a larger area of the Northeast and Canada that appears to have more acid rainfall than the rest of the country. It is downwind from major coal burning states, which produce about one quarter of US SO/sub 2/ emissions and one sixth of nitrogen oxide emissions. Uncertainties exist over the causes of forest damage and more research is needed before advocating expensive programs to reduce rain acidity. The President's current budget seeks an expansion of research funds from the current $30 million per year to $120 million.

  14. Simulation of water drainage of a rain forest and forest conversion plots using a soil water model

    NASA Astrophysics Data System (ADS)

    Klinge, R.; Schmidt, J.; Fölster, H.

    2001-06-01

    The water budgets were estimated for a rain forest plot and two conversion plots (cut and burn) in a rain forest region of eastern Amazonia, Brazil, using a soil water model (SilVlow) to estimate the drainage and soil water storage compartments. A quantification of drainage was required to determine element leaching associated with conversion. The plots were equipped with fast recording tensiometer fields down to 5 m depth. Soil water tension and meteorological data were recorded at 15 min intervals. Monitoring was maintained for 18 months from July 1992 to December 1993. The special feature of the model is that soil parameter functions (matric potential/ volumetric moisture content and matric potential/ hydraulic conductivity) are introduced in tabular form, and can be changed deliberately during a fitting procedure adjusting simulated to measured matric potential. This fitting requires a vegetation-free period, which was provided by the conversion plots after clear-cutting the forest. For this fitting procedure, high-resolution recording was essential. Actual evapotranspiration in the soil water model is derived from potential (Penman) evaporation using a matric potential-dependent transpiration reduction function. The adjustment of these parameter functions was performed on plots under vegetation, also by fitting. The annual rainfall of 2479-2706 mm (depending on time interval chosen), fell short of the long-term average of 3000 mm. The forest intercepted 15% of the rain while total evapotranspiration was about 1350 mm. Drainage decreased from 1484-1733 mm at 110 cm to 1130-1331 mm at 500 cm suggesting a water uptake by roots of 350-400 mm from the depth zone 110-500 cm. On the conversion plots that were planted with eucalypts but regularly weeded, drainage at 500 cm depth amounted to >90% of rainfall.

  15. Inter-comparison of automatic rain gauges

    NASA Technical Reports Server (NTRS)

    Nystuen, Jeffrey A.

    1994-01-01

    The Ocean Acoustics Division (OAD) of the Atlantic Oceanographic and Meteorological Laboratory (AOML), in cooperation with NOAA/NESDIS and NASA, has deployed six rain gauges for calibration and intercomparison purposes. These instruments include: (1) a weighing rain gauge, (2) a RM Young Model 50202 capacitance rain gauge, (3) a ScTI ORG-705 (long path) optical rain gauge, (4) a ScTI ORG-105 (mini-ORG) optical rain gauge, (5) a Belfort Model 382 tipping bucket rain gauge, and (6) a Distromet RD-69 disdrometer. The system has been running continuously since July 1993. During this time period, roughly 150 events with maximum rainfall rate over 10 mm/hr and 25 events with maximum rainfall rates over 100 mm/hr have been recorded. All rain gauge types have performed well, with intercorrelations 0.9 or higher. However, limitations for each type of rain gauge have been observed.

  16. Rain, fog, and clouds for aircraft simulators

    NASA Technical Reports Server (NTRS)

    Chase, W. D.

    1981-01-01

    Environmental chamber creates realistic fog and rain effects in aircraft simulator. It reproduces clouds, homogeneous fog, patches of fog, rain and fog, and rain only. It is used with real time digital computer, color computer generated image display that simulates airport lights, or color television camera that produces moving display of airport runway as depicted on model terrain board.

  17. Acid rain control: the costs of compliance

    SciTech Connect

    Gilleland, D.S.; Swisher, J.H.

    1985-01-01

    This document is the proceedings from a conference sponsored by the Illinois Energy Resources Commission and the Coal Extraction and Utilization Research Center, Southern Illinois University at Carbondale and held in Carbondale on March 18, 1984. Topics addressed include: the sources and impacts of acid rain, the problems inherent in modeling the impacts of acid rain legislation, the effects of acid rain legislation on the socio-economic sector, compliance costs, and the impact of acid rain legislation on related industries (railroads).

  18. Acid rain

    SciTech Connect

    Boyle, R.H.; Boyle, R.A.

    1983-01-01

    Acid rain, says Boyle is a chemical leprosy eating into the face of North America and Europe, perhaps the major ecological problem of our time. Boyle describes the causes and scope of the phenomenon; the effects on man, wildlife, water, and our cultural heritage. He probes the delays of politicians and the frequent self-serving arguments advanced by industry in the face of what scientists have proved. The solutions he offers are to strengthen the Clean Air Act and require emission reductions that can be accomplished by establishing emission standards on a regional or bubble basis, burn low-sulfur coal, install scrubbers at critical plants, and invest in alternative energy sources. 73 references, 1 figure.

  19. Acid rain

    SciTech Connect

    Sweet, W.

    1980-06-20

    Acid precipitation includes not only rain but also acidified snow, hail and frost, as well as sulfur and nitrogen dust. The principal source of acid precipitation is pollution emitted by power plants and smelters. Sulfur and nitrogen compounds contained in the emissions combine with moisture to form droplets with a high acid content - sometimes as acidic as vinegar. When sufficiently concentrated, these acids can kill fish and damage material structures. Under certain circumstances they may reduce crop and forest yields and cause or aggravate respiratory diseases in humans. During the summer, especially, pollutants tend to collect over the Great Lakes in high pressure systems. Since winds typically are westerly and rotate clockwise around high pressure systems, the pollutants gradually are dispersed throughout the eastern part of the continent.

  20. Soak Up the Rain

    EPA Pesticide Factsheets

    Soak Up the Rain promotes green infrastructure practices such as rain barrels, rain gardens, permeable pavements and green roofs to reduce stormwater runoff and prevent water pollution while bringing about a broad range of community benefits.

  1. A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. 3: A stochastic rain fade control algorithm for satellite link power via non linear Markow filtering theory

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1991-01-01

    The dynamic and composite nature of propagation impairments that are incurred on Earth-space communications links at frequencies in and above 30/20 GHz Ka band, i.e., rain attenuation, cloud and/or clear air scintillation, etc., combined with the need to counter such degradations after the small link margins have been exceeded, necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) Project by the implementation of optimal processing schemes derived through the use of the Rain Attenuation Prediction Model and nonlinear Markov filtering theory.

  2. Application of the NCAR regional climate model to eastern Africa: 1. Simulation of the short rains of 1988

    NASA Astrophysics Data System (ADS)

    Sun, Liqiang; Semazzi, Fredrick H. M.; Giorgi, Filippo; Ogallo, Laban

    1999-03-01

    The National Center for Atmospheric Research (NCAR) Regional Climate Model (RegCM2) is employed to investigate the physical mechanisms that govern the October-December rains over eastern Africa. The model employs the Mercator conformai projection, with a domain of 5580 km × 5040 km centered at 31°E, 4°S, and a horizontal grid point spacing of 60 km. The simulation period is October-December 1988, and the model initial and lateral boundary conditions are taken from ECMWF reanalysis. A number of month-long simulations have been conducted to optimize various parameterizations of the model which include the following factors: cumulus convection, moisture parameterization, radiative transfer formulation, surface processes, boundary layer physics, and the lateral boundary conditions. The model was successfully customized over eastern Africa. The model simulates the large-scale circulation characteristics over the region as well as local features such as the dominant precipitation maxima, the Turkana low-level jet, and the diurnal reversal in the lake/land breeze circulation over Lake Victoria. Several model deficiencies are also identified. They include a negative rainfall bias over the western portions of the domain and the Kenya Highlands and a temperature bias over the tropical forest regions. Systematic analysis of surface water budget reveals that evapotranspiration is a major sink in the water budget over the regions where precipitation is moderate or small, while the role of runoff and drainage becomes important over the regions where precipitation is abundant. The model simulations also suggest that during the short-rains season, the large-scale circulation anomalies play the most important role in shaping the precipitation anomalies.

  3. Modeling the influence of hypsometry, vegetation, and storm energy on snowmelt contributions to basins during rain-on-snow floods

    NASA Astrophysics Data System (ADS)

    Wayand, Nicholas E.; Lundquist, Jessica D.; Clark, Martyn P.

    2015-10-01

    Point observations and previous basin modeling efforts have suggested that snowmelt may be a significant input of water for runoff during extreme rain-on-snow floods within western U.S. basins. Quantifying snowmelt input over entire basins is difficult given sparse observations of snowmelt. In order to provide a range of snowmelt contributions for water managers, a physically based snow model coupled with an idealized basin representation was evaluated in point simulations and used to quantify the maximum basin-wide input from snowmelt volume during flood events. Maximum snowmelt basin contributions and uncertainty ranges were estimated as 29% (11-47%), 29% (8-37%), and 7% (2-24%) of total rain plus snowmelt input, within the Snoqualmie, East North Fork Feather, and Upper San Joaquin basins, respectively, during historic flooding events between 1980 and 2008. The idealized basin representation revealed that both hypsometry and forest cover of a basin had similar magnitude of impacts on the basin-wide snowmelt totals. However, the characteristics of a given storm (antecedent SWE and available energy for melt) controlled how much hypsometry and forest cover impacted basin-wide snowmelt. These results indicate that for watershed managers, flood forecasting efforts should prioritize rainfall prediction first, but cannot neglect snowmelt contributions in some cases. Efforts to reduce the uncertainty in the above snowmelt simulations should focus on improving the meteorological forcing data (especially air temperature and wind speed) in complex terrain.

  4. Dynamic gauge adjustment of high-resolution X-band radar data for convective rain storms: Model-based evaluation against measured combined sewer overflow

    NASA Astrophysics Data System (ADS)

    Borup, Morten; Grum, Morten; Linde, Jens Jørgen; Mikkelsen, Peter Steen

    2016-08-01

    Numerous studies have shown that radar rainfall estimates need to be adjusted against rain gauge measurements in order to be useful for hydrological modelling. In the current study we investigate if adjustment can improve radar rainfall estimates to the point where they can be used for modelling overflows from urban drainage systems, and we furthermore investigate the importance of the aggregation period of the adjustment scheme. This is done by continuously adjusting X-band radar data based on the previous 5-30 min of rain data recorded by multiple rain gauges and propagating the rainfall estimates through a hydraulic urban drainage model. The model is built entirely from physical data, without any calibration, to avoid bias towards any specific type of rainfall estimate. The performance is assessed by comparing measured and modelled water levels at a weir downstream of a highly impermeable, well defined, 64 ha urban catchment, for nine overflow generating rain events. The dynamically adjusted radar data perform best when the aggregation period is as small as 10-20 min, in which case it performs much better than static adjusted radar data and data from rain gauges situated 2-3 km away.

  5. The Implications of ACTS Technology on the Requirements of Rain Attenuation Modeling for Communication System Specification and Analysis at 30/20 GHz and Beyond

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1996-01-01

    The advent of the use of the Ka-Band for space communications, coupled with the introduction of digital modulation techniques as well as multiple-beam methodology for satellites, has deemed it necessary to reassess the plethora of rain attenuation prediction models in use. The Advanced Communication Technology Satellite (ACTS) Project, undertaken by the National Aeronautics and Space Administration in 1983, offered such challenges to rain attenuation prediction modeling. Up to 1983, no such single modeling formalism existed that could fill such requirements. Not even the work done by the NASA Propagation Experimenters (NAPEX) Group had envisioned such requirements, so no dynamic Ka-Band data existed from which one could draw conclusions. In this paper, the basic rudiments of what has become to be known as the 'ACTS Rain Attenuation Prediction Model' will be presented. The concept of rain fade mitigation control availability will be introduced. A new evaluation is then presented for the performance of satellite communication systems, in particular, those to be operating within the Ka-Band and above, that will necessarily employ some type of dynamic rain fade mitigation procedure.

  6. A model for estimating rains' area, using the dependence of the time correlation of sites' monthly precipitation totals on the distance between sites

    NASA Astrophysics Data System (ADS)

    Walanus, Adam; Cebulska, Marta; Twardosz, Robert

    2016-05-01

    Based on the monthly precipitation series from 16 sites (in the Polish Carpathian Mountains), of 132 years' length, a relatively precise scatterplot of correlation coefficients between sites versus distance between sites is obtained. The "rains" of Gaussian shape, in the spatial sense, are a good model, which produces a scatterplot very closely resembling the observed one. The essential parameter of the model is the area covered by the modeled rains, which results to be of order 30-50 km, though with about a twice lower value for the N-S direction.

  7. Correction of the High-Latitude Rain Day Anomaly in the NCEP NCAR Reanalysis for Land Surface Hydrological Modeling.

    NASA Astrophysics Data System (ADS)

    Sheffield, Justin; Ziegler, Alan D.; Wood, Eric F.; Chen, Yangbo

    2004-10-01

    A spurious wavelike pattern in the monthly rain day statistics exists within the National Centers for Environmental Prediction National Center for Atmospheric Research (NCEP NCAR) reanalysis precipitation product. The anomaly, which is an artifact of the parameterization of moisture diffusion, occurs during the winter months in the Northern and Southern Hemisphere high latitudes. The anomaly is corrected by using monthly statistics from three different global precipitation products from 1) the University of Washington (UW), 2) the Global Precipitation Climate Project (GPCP), and 3) the Climatic Research Unit (CRU), resulting in three slightly different corrected precipitation products. The correction methodology, however, compromises spatial consistency (e.g., storm tracking) on a daily time scale. The effect that the precipitation correction has on the reanalysis-derived global land surface water budgets is investigated by forcing the Variable Infiltration Capacity (VIC) land surface model with all four datasets (i.e., the original reanalysis product and the three corrected datasets). The main components of the land surface water budget cycle are not affected substantially; however, the increased spatial variability in precipitation is reflected in the evaporation and runoff components but reduced in the case of soil moisture. Furthermore, the partitioning of precipitation into canopy evaporation and throughfall is sensitive to the rain day statistics of the correcting dataset, especially in the Tropics, and this has implications for the required accuracy of the correcting dataset. The output fields from these long-term land surface simulations provide a global, consistent dataset of water and energy states and fluxes that can be used for model intercomparisons, studies of annual and seasonal climate variability, and comparisons with current versions of numerical weather prediction models.


  8. Quasar Rain

    NASA Astrophysics Data System (ADS)

    Elvis, Martin

    2015-01-01

    Velocity resolved reverberation mapping (VRRM) has shown clear evidence for inflows in the broad emission line (BEL) region of active galactic nuclei: redshifted BELs at zero lag (AGNs, e.g. Arp 151, Bentz et al. 2010; Grier et al. 2013). While radiative transfer in rotating disks can give shorter red side lags than blue, a zero lag has to be along our line of sight, so it is hard to escape infall. The BEL region is normally considered to be rotating or in outflow so this result is a surprise. Infalling BEL gas cannot fall far without the need to lose angular momentum for accreting gas producing an accretion disk.I suggest that quasar continuum irradiation induced cooling instabilities (Chakravorty et al 2009; Krolik, McKee & Tarter 1981) lead to dense BEL clouds condensing out of the semi-ubiquitous warm absorber (WA) outflows found in AGNs and that these clouds may produce a VRRM inflow signature.Unlike WA gas, dense high column density BEL clouds are hard to accelerate with radiation pressure (Risaliti & Elvis 2010; Mushotzky, Solomon & Strittmatter 1972). BEL clouds will thus stall in the outflow and begin to fall back toward the central black hole after a dynamical time, 'raining out' of the WA medium. If these BEL clouds condense out before these outflows reach escape velocity [v(esc)] then this inflow can potentially produce the observed VRRM signature. As the clouds fall back in they will be moving on elliptical orbits supersonically through the WA gas with Mach number ~(2000 km/s)/(100km/s) ~20. This will produce comet-like structures with narrow opening angles, as seen in asymmetric X-ray absorbing 'eclipses' (Maiolino et al. 2010). They will survive only a few months, as required to avoid forming a disk. For this picture to work the condensation time must be less than the acceleration time to v(esc) and the destruction time must be longer than the dynamical time.

  9. A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. 1: Theoretical development and application to yearly predictions for selected cities in the United States

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1986-01-01

    A rain attenuation prediction model is described for use in calculating satellite communication link availability for any specific location in the world that is characterized by an extended record of rainfall. Such a formalism is necessary for the accurate assessment of such availability predictions in the case of the small user-terminal concept of the Advanced Communication Technology Satellite (ACTS) Project. The model employs the theory of extreme value statistics to generate the necessary statistical rainrate parameters from rain data in the form compiled by the National Weather Service. These location dependent rain statistics are then applied to a rain attenuation model to obtain a yearly prediction of the occurrence of attenuation on any satellite link at that location. The predictions of this model are compared to those of the Crane Two-Component Rain Model and some empirical data and found to be very good. The model is then used to calculate rain attenuation statistics at 59 locations in the United States (including Alaska and Hawaii) for the 20 GHz downlinks and 30 GHz uplinks of the proposed ACTS system. The flexibility of this modeling formalism is such that it allows a complete and unified treatment of the temporal aspects of rain attenuation that leads to the design of an optimum stochastic power control algorithm, the purpose of which is to efficiently counter such rain fades on a satellite link.

  10. Testing mixing models of old and young groundwater in a tropical lowland rain forest with environmental tracers

    USGS Publications Warehouse

    Solomon, D. Kip; Genereux, David P.; Plummer, L. Niel; Busenberg, Eurybiades

    2010-01-01

    We tested three models of mixing between old interbasin groundwater flow (IGF) and young, locally derived groundwater in a lowland rain forest in Costa Rica using a large suite of environmental tracers. We focus on the young fraction of water using the transient tracers CFC-11, CFC-12, CFC-113, SF6, 3H, and bomb 14C. We measured 3He, but 3H/3He dating is generally problematic due to the presence of mantle 3He. Because of their unique concentration histories in the atmosphere, combinations of transient tracers are sensitive not only to subsurface travel times but also to mixing between waters having different travel times. Samples fall into three distinct categories: (1) young waters that plot along a piston flow line, (2) old samples that have near-zero concentrations of the transient tracers, and (3) mixtures of 1 and 2. We have modeled the concentrations of the transient tracers using (1) a binary mixing model (BMM) of old and young water with the young fraction transported via piston flow, (2) an exponential mixing model (EMM) with a distribution of groundwater travel times characterized by a mean value, and (3) an exponential mixing model for the young fraction followed by binary mixing with an old fraction (EMM/BMM). In spite of the mathematical differences in the mixing models, they all lead to a similar conceptual model of young (0 to 10 year) groundwater that is locally derived mixing with old (>1000 years) groundwater that is recharged beyond the surface water boundary of the system.

  11. Testing mixing models of old and young groundwater in a tropical lowland rain forest with environmental tracers

    NASA Astrophysics Data System (ADS)

    Solomon, D. Kip; Genereux, David P.; Plummer, L. Niel; Busenberg, Eurybiades

    2010-04-01

    We tested three models of mixing between old interbasin groundwater flow (IGF) and young, locally derived groundwater in a lowland rain forest in Costa Rica using a large suite of environmental tracers. We focus on the young fraction of water using the transient tracers CFC-11, CFC-12, CFC-113, SF6, 3H, and bomb 14C. We measured 3He, but 3H/3He dating is generally problematic due to the presence of mantle 3He. Because of their unique concentration histories in the atmosphere, combinations of transient tracers are sensitive not only to subsurface travel times but also to mixing between waters having different travel times. Samples fall into three distinct categories: (1) young waters that plot along a piston flow line, (2) old samples that have near-zero concentrations of the transient tracers, and (3) mixtures of 1 and 2. We have modeled the concentrations of the transient tracers using (1) a binary mixing model (BMM) of old and young water with the young fraction transported via piston flow, (2) an exponential mixing model (EMM) with a distribution of groundwater travel times characterized by a mean value, and (3) an exponential mixing model for the young fraction followed by binary mixing with an old fraction (EMM/BMM). In spite of the mathematical differences in the mixing models, they all lead to a similar conceptual model of young (0 to 10 year) groundwater that is locally derived mixing with old (>1000 years) groundwater that is recharged beyond the surface water boundary of the system.

  12. Development of a succession model for subtropical rain forest and its application to assess the effects of timber harvest at Wiangaree State Forest, New South Wales

    SciTech Connect

    Shugart, H.H. Jr.; Hopkins, M.S.; Burgess, I.P.; Mortlock, A.T.

    1980-11-01

    The KIAMBRAM model, a computer model of complex notophyll vine forest (subtropical rain forest) in Australia near the New South Wales/Queensland border, is documented and results of the model are presented. The model simulates a 1/20-ha forest stand by considering explicitly the birth, death, and growth of each tree in the stand. The model also allows the selective harvest of any of the 125 species considered at any desired frequency. The model is tested on its ability to simulate species dynamics following disturbance and to predict the composition of mature forest. The model is used to assess the consequences of the harvest of commercial species from the complex notophyll vine forest both in terms of a single harvest and of a repeated harvest. The KIAMBRAM model predicts that repeated logging on a 30-year cycle would lead to rain forest in which cover was maintained but species composition altered. The composition would shift toward species of earlier successional stages, of lower value as logs. The volume available for harvest would be smaller. Application of the model to other tropical rain forests in discussed.

  13. Understanding Acid Rain

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  14. The Acid Rain Reader.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  15. No Rain, No Gain

    ERIC Educational Resources Information Center

    Perna, Mark C.

    2005-01-01

    Marketing is like the rain. Some people are quickly aware of it, while others take repeated and consistent drops for quite an extended period of time before they take action. Building on the marketing principles discussed in previous issues, the next key principle to smart marketing is the "Rain Effect." The Rain Effect is the use of consistent…

  16. Acid Rain Study Guide.

    ERIC Educational Resources Information Center

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  17. The Children's Rain Forest.

    ERIC Educational Resources Information Center

    Thornton, Carol A.; And Others

    1995-01-01

    Describes a unit on rain forests in which first graders studied about rain forests, built a classroom rain forest, and created a bulletin board. They also graphed rainfall, estimated body water, and estimated the number of newspapers that could be produced from one canopy tree. (MKR)

  18. HYDROLOGIC MODELING OF AN EASTERN PENNSYLVANIA WATERSHED WITH NEXRAD AND RAIN GAUGE DATA

    EPA Science Inventory

    This paper applies the Soil Water Assessment Tool (SWAT) to model the hydrology in the Pocono Creek watershed located in Monroe County, Pa. The calibrated model will be used in a subsequent study to examine the impact of population growth and rapid urbanization in the watershed o...

  19. More rain compensation results

    NASA Technical Reports Server (NTRS)

    Sworder, D. D.; Vojak, R.

    1992-01-01

    To reduce the impact of rain-induced attenuation in the 20/30 GHz band, the attenuation at a specified signal frequency must be estimated and extrapolated forward in time on the basis of a noisy beacon measurement. Several studies have used model based procedures for solving this problem in statistical inference. Perhaps the most widely used model-based paradigm leads to the Kalman filter and its lineal variants. In this formulation, the dynamic features of the attenuation are represented by a state process (x(sub t)). The observation process (y(sub t)) is derived from beacon measurements. Some ideas relating to the signal processing problems related to uplink power control are presented. It is shown that some easily implemented algorithms hold promise for use in estimating rain induced fades. The algorithms were applied to actual data generated at the Virginia Polytechnic Institute and State University (VPI) test facility. Because only one such event was studied, it is not clear that the algorithms will have the same effectiveness when a wide range of events are studied.

  20. Kinematics of coronal rain in a transversely oscillating loop: Ponderomotive force and rain-excited oscillations

    NASA Astrophysics Data System (ADS)

    Verwichte, E.; Antolin, P.; Rowlands, G.; Kohutova, P.; Neukirch, T.

    2017-01-01

    Context. Coronal rain is composed of cool dense blobs that form in solar coronal loops and are a manifestation of catastrophic cooling linked to thermal instability. Once formed, rain falls towards the solar surface at sub-ballistic speeds, which is not well understood. Pressure forces seem to be the prime candidate to explain this. In many observations rain is accompanied by transverse oscillations and the interaction between rain and these oscillations needs to be explored. Aims: Therefore, an alternative kinematic model for coronal rain kinematics in transversely oscillating loops is developed to understand the physical nature of the observed sub-ballistic falling motion of rain. This model explicitly explores the role of the ponderomotive force arising from the transverse oscillation on the rain motion and the capacity of rain to excite wave motion. Methods: An analytical model is presented that describes a rain blob guided by the coronal magnetic field supporting a one-dimensional shear Alfvén wave as a point mass on an oscillating string. The model includes gravity and the ponderomotive force from the oscillation acting on the mass and the inertia of the mass acting on the oscillation. Results: The kinematics of rain in the limit of negligible rain mass are explored and falling and trapped regimes are found, depending on wave amplitude. In the trapped regime for the fundamental mode, the rain blob bounces back and forth around the loop top at a long period that is inversely proportional to the oscillation amplitude. The model is compared with several observational rain studies, including one in-depth comparison with an observation that shows rain with up-and-down bobbing motion. The role of rain inertia in exciting transverse oscillations is explored in inclined loops. Conclusions: It is found that the model requires displacement amplitudes of the transverse oscillation that are typically an order of magnitude larger than observed to explain the measured sub

  1. Comparison of SWAT Model Water Balance Calibration Using NEXRAD and Surface Rain Gauge Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The value of watershed-scale, water quality models to ecosystem management is increasingly evident as more programs adopt these tools to help assess the effectiveness of different management scenarios on the environment. The USDA-Conservation Effects Assessment Project (CEAP) is one such program whi...

  2. A Predictor Model for SHF and EHF MILSATCOM System Availabilities in the Presence of Rain.

    DTIC Science & Technology

    1980-02-21

    A numerical method for computing MILSATCOM system availability based on predicted link availability is described. Link availability can be computed in the model for frequencies of 10-50 GHz, arbitrary geostationary satellite subpoint, and arbitrary value of link margin in dB. Computed availability contours are plotted on a Mercator grid of the world . (Author)

  3. Bayesian thermal evolution models for giant planets: Helium rain and double-diffusive convection in Jupiter

    NASA Astrophysics Data System (ADS)

    Mankovich, Christopher; Fortney, Jonathan J.; Nettelmann, Nadine; Moore, Kevin

    2016-10-01

    Hydrogen and helium unmix when sufficiently cool, and this bears on the thermal evolution of all cool giant planets at or below one Jupiter mass. Over the past few years, ab initio simulations have put us in the era of quantitative predictions for this H-He immiscibility at megabar pressures. We present models for the thermal evolution of Jupiter, including its evolving helium distribution following one such ab initio H-He phase diagram. After 4 Gyr of homogeneous evolution, differentiation establishes a helium gradient between 1 and 2 Mbar that dynamically stabilizes the fluid to overturning convection. The result is a region undergoing overstable double-diffusive convection (ODDC), whose relatively weak vertical heat transport maintains a superadiabatic temperature gradient. With a general parameterization for the ODDC efficiency, the models can reconcile Jupiter's intrinsic flux, atmospheric helium content, and mean radius at the age of the solar system if the H-He phase diagram is translated to cooler temperatures.We cast our nonadiabatic thermal evolution models in a Markov chain Monte Carlo parameter estimation framework, retrieving the total heavy element mass, the superadiabaticity of the deep temperature gradient, and the phase diagram temperature offset. Models using the interpolated Saumon, Chabrier and van Horn (1995) equation of state (SCvH-I) favor very inefficient ODDC such that the deep temperature gradient is strongly superadiabatic, forming a thermal boundary layer that allows the molecular envelope to cool quickly while the deeper interior (most of the planet's mass) actually heats up over time. If we modulate the overall cooling time with an additional free parameter, mimicking the effect of a colder or warmer EOS, the models favor those that are colder than SCvH-I; this class of EOS is also favored by shock experiments. The models in this scenario have more modest deep superadiabaticities such that the envelope cools more gradually and the deep

  4. Bayesian Evolution Models for Jupiter with Helium Rain and Double-diffusive Convection

    NASA Astrophysics Data System (ADS)

    Mankovich, Christopher; Fortney, Jonathan J.; Moore, Kevin L.

    2016-12-01

    Hydrogen and helium demix when sufficiently cool, and this bears on the evolution of all giant planets at large separations at or below roughly a Jupiter mass. We model the thermal evolution of Jupiter, including its evolving helium distribution following results of ab initio simulations for helium immiscibility in metallic hydrogen. After 4 Gyr of homogeneous evolution, differentiation establishes a thin helium gradient below 1 Mbar that dynamically stabilizes the fluid to convection. The region undergoes overstable double-diffusive convection (ODDC), whose weak heat transport maintains a superadiabatic temperature gradient. With a generic parameterization for the ODDC efficiency, the models can reconcile Jupiter’s intrinsix flux, atmospheric helium content, and radius at the age of the solar system if the Lorenzen et al. H-He phase diagram is translated to lower temperatures. We cast the evolutionary models in an MCMC framework to explore tens of thousands of evolutionary sequences, retrieving probability distributions for the total heavy-element mass, the superadiabaticity of the temperature gradient due to ODDC, and the phase diagram perturbation. The adopted SCvH-I equation of state (EOS) favors inefficient ODDC such that a thermal boundary layer is formed, allowing the molecular envelope to cool rapidly while the deeper interior actually heats up over time. If the overall cooling time is modulated with an additional free parameter to imitate the effect of a colder or warmer EOS, the models favor those that are colder than SCvH-I. In this case the superadiabaticity is modest and warming and cooling deep interiors are equally likely.

  5. Molecular Characterization of Three Canine Models of Human Rare Bone Diseases: Caffey, van den Ende-Gupta, and Raine Syndromes.

    PubMed

    Hytönen, Marjo K; Arumilli, Meharji; Lappalainen, Anu K; Owczarek-Lipska, Marta; Jagannathan, Vidhya; Hundi, Sruthi; Salmela, Elina; Venta, Patrick; Sarkiala, Eva; Jokinen, Tarja; Gorgas, Daniela; Kere, Juha; Nieminen, Pekka; Drögemüller, Cord; Lohi, Hannes

    2016-05-01

    One to two percent of all children are born with a developmental disorder requiring pediatric hospital admissions. For many such syndromes, the molecular pathogenesis remains poorly characterized. Parallel developmental disorders in other species could provide complementary models for human rare diseases by uncovering new candidate genes, improving the understanding of the molecular mechanisms and opening possibilities for therapeutic trials. We performed various experiments, e.g. combined genome-wide association and next generation sequencing, to investigate the clinico-pathological features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified pathogenic variants in the canine SLC37A2 (truncating splicing enhancer variant), SCARF2 (truncating 2-bp deletion) and FAM20C (missense variant) genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease), for which SLC37A2 is a new candidate gene. SLC37A2 is a poorly characterized member of a glucose-phosphate transporter family without previous disease associations. It is expressed in many tissues, including cells of the macrophage lineage, e.g. osteoclasts, and suggests a disease mechanism, in which an impaired glucose homeostasis in osteoclasts compromises their function in the developing bone, leading to hyperostosis. Mutations in SCARF2 and FAM20C have been associated with the human van den Ende-Gupta and Raine syndromes that include numerous features similar to the affected dogs. Given the growing interest in the molecular characterization and treatment of human rare diseases, our study presents three novel physiologically relevant models for further research and therapy approaches, while providing the molecular identity for the canine conditions.

  6. Molecular Characterization of Three Canine Models of Human Rare Bone Diseases: Caffey, van den Ende-Gupta, and Raine Syndromes

    PubMed Central

    Hytönen, Marjo K.; Arumilli, Meharji; Lappalainen, Anu K.; Owczarek-Lipska, Marta; Jagannathan, Vidhya; Hundi, Sruthi; Salmela, Elina; Venta, Patrick; Sarkiala, Eva; Jokinen, Tarja; Gorgas, Daniela; Kere, Juha; Nieminen, Pekka

    2016-01-01

    One to two percent of all children are born with a developmental disorder requiring pediatric hospital admissions. For many such syndromes, the molecular pathogenesis remains poorly characterized. Parallel developmental disorders in other species could provide complementary models for human rare diseases by uncovering new candidate genes, improving the understanding of the molecular mechanisms and opening possibilities for therapeutic trials. We performed various experiments, e.g. combined genome-wide association and next generation sequencing, to investigate the clinico-pathological features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified pathogenic variants in the canine SLC37A2 (truncating splicing enhancer variant), SCARF2 (truncating 2-bp deletion) and FAM20C (missense variant) genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease), for which SLC37A2 is a new candidate gene. SLC37A2 is a poorly characterized member of a glucose-phosphate transporter family without previous disease associations. It is expressed in many tissues, including cells of the macrophage lineage, e.g. osteoclasts, and suggests a disease mechanism, in which an impaired glucose homeostasis in osteoclasts compromises their function in the developing bone, leading to hyperostosis. Mutations in SCARF2 and FAM20C have been associated with the human van den Ende-Gupta and Raine syndromes that include numerous features similar to the affected dogs. Given the growing interest in the molecular characterization and treatment of human rare diseases, our study presents three novel physiologically relevant models for further research and therapy approaches, while providing the molecular identity for the canine conditions. PMID:27187611

  7. The value of data availability versus model complexity to estimate snow, glacier and rain water in mountain streams

    NASA Astrophysics Data System (ADS)

    Finger, David; Vis, Marc; Seibert, Jan

    2014-05-01

    The contribution of snow, glacier and rainwater to runoff in mountain streams is of major importance for water resources managers as climate change is expected to impact on all three sources (e.g. Huss, 2012). While glaciers are retreating worldwide, the snow cover during winter becomes shorter and precipitations events become more intense (e.g. Finger et al., 2012). Besides field investigation such as chemical fingerprints in water samples and artificial tracer experiments (e.g. Finger et al., 2013), the contribution of snow, glacier and rain can also be estimated with hydrological models, given that the modeling accounts adequately for snow-, glacier and rainwater runoff (Finger et al., 2011). We present a multi-variable calibration technique to estimate runoff composition using the conceptual HBV-light model (Seibert and Vis, 2012). The model code was extended to allow calibration and validation of simulations against glacier mass balances and satellite derived snow cover area, in addition to the usual comparison against measured discharge. We tested the value of these additional data sets on three meso-scale catchments in Switzerland: i) Rhoneglacier (39km2; ~50% glaciation), ii) Hinterrhein (53km2; ~17% glaciation) and iii) Silvretta glacier (103km2; ~8% glaciation). We also compared the results to a similar study performed with a physically based, fully distributed hydrological model (Finger et al., 2011). Preliminary results indicate that all three observational datasets are reproduced adequately by the model, allowing an accurate estimation of the runoff composition in the three mountain streams. However, the use of runoff alone to calibrate the model leads to unrealistic snow- and glacier melt, expressed by a low overall model performance. These results are in line with previous studies carried out with a more complex, physically based fully distributed hydrological model (Finger et al. 2011). Based on these results we conclude that it is essential to use

  8. Voronoi Diagrams and Spring Rain

    ERIC Educational Resources Information Center

    Perham, Arnold E.; Perham, Faustine L.

    2011-01-01

    The goal of this geometry project is to use Voronoi diagrams, a powerful modeling tool across disciplines, and the integration of technology to analyze spring rainfall from rain gauge data over a region. In their investigation, students use familiar equipment from their mathematical toolbox: triangles and other polygons, circumcenters and…

  9. Raining on black holes and massive galaxies: the top-down multiphase condensation model

    NASA Astrophysics Data System (ADS)

    Gaspari, M.; Temi, P.; Brighenti, F.

    2017-04-01

    The plasma haloes filling massive galaxies, groups and clusters are shaped by active galactic nucleus (AGN) heating and subsonic turbulence (σv ∼ 150 km s-1), as probed by Hitomi. Novel 3D high-resolution simulations show the soft X-ray, keV hot plasma cools rapidly via radiative emission at the high-density interface of the turbulent eddies, stimulating a top-down condensation cascade of warm 104 K filaments. The kpc-scale ionized (optical/ultraviolet) filaments form a skin enveloping the neutral filaments (optical/infrared/21 cm). The peaks of the warm filaments further condense into cold molecular clouds (<50 K; radio) with total mass of several 107 M⊙ and inheriting the turbulent kinematics. In the core, the clouds collide inelastically, mixing angular momentum and leading to Chaotic Cold Accretion (CCA). The black hole accretion rate (BHAR) can be modelled via quasi-spherical viscous accretion, dot{M}_bullet ∝ ν _c, with clump collisional viscosity νc ≡ λc σv and λc ∼ 100 pc. Beyond the core, pressure torques shape the angular momentum transport. In CCA, the BHAR is recurrently boosted up to 2 dex compared with the disc evolution, which arises as turbulence becomes subdominant. With negligible rotation too, compressional heating inhibits the molecular phase. The CCA BHAR distribution is lognormal with pink noise, f-1 power spectrum characteristic of fractal phenomena. Such chaotic fluctuations can explain the rapid luminosity variability of AGN and high-mass X-ray binaries. An improved criterium to trace non-linear condensation is proposed: σv/vcool ≲ 1. The three-phase CCA reproduces key observations of cospatial multiphase gas in massive galaxies, including Chandra X-ray images, SOAR Hα filaments and kinematics, Herschel [C+] emission and ALMA molecular associations. CCA plays important role in AGN feedback and unification, the evolution of BHs, galaxies and clusters.

  10. ACTS Rain Fade Compensation

    NASA Technical Reports Server (NTRS)

    Coney, Thom A.

    1996-01-01

    Performance status of the Adaptive Rain Fade Compensation includes: (1) The rain fade protocol is functional detecting fades, providing an additional 10 dB of margin and seamless transitions to and from coded operation; (2) The stabilization of the link margins and the optimization of rain fade decision thresholds has resulted in improved BER performance; (3) Characterization of the fade compensation algorithm is ongoing.

  11. USGS Tracks Acid Rain

    USGS Publications Warehouse

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  12. Retrospective analysis of a non-forecasted rain-on-snow flood in the Alps - a matter of model-limitations or unpredictable nature?

    NASA Astrophysics Data System (ADS)

    Rössler, O.; Froidevaux, P.; Börst, U.; Rickli, R.; Martius, O.; Weingartner, R.

    2013-10-01

    On 10 October 2011, a rain-on-snow flood occurred in the Bernese Alps, Switzerland, and caused significant damage. As this flood peak was unpredicted by the flood forecast system, questions were raised concerning what has caused this flood and whether it was predictable at all. In this study, we focused on one valley that was heavily hit by the event, the Loetschen valley (160 km2), and aimed to reconstruct the anatomy of this rain-on-snow flood from the synoptic conditions represented by European Centre for Medium-Range Weather Forecasts ECWMF analysis data, and the local meteorology within the valley recorded by an extensive met-station network. In addition, we applied the hydrological model WaSiM-ETH to improve our hydrological process understanding about this event and to demonstrate the predictability of this rain-on-snow flood. We found an atmospheric river bringing moist and warm air to Switzerland that followed an anomalous cold front with sustained snowfall to be central for this rain-on-snow event. Intensive rainfall (average 100 mm day-1) was accompanied by a drastic temperature increase (+8 K) that shifted the zero degree line from 1500 m a.s.l. to 3200 m a.s.l. in 12 h. The northern flank of the valley received significantly more precipitation than the southern flank, leading to an enormous flood in tributaries along the northern flank, while the tributaries along the southern flank remained nearly unchanged. We hypothesized that the reason for this was a cavity circulation combined with a seeder-feeder-cloud system enhancing both local rainfall and snow melt by condensation of the warm, moist air on the snow. Applying and adjusting the hydrological model, we show that both the latent and the sensible heat fluxes were responsible for the flood and that locally large amounts of precipitation (up to 160 mm rainfall in 12 h) was necessary to produce the estimated flood peak. With considerable adjustments to the model and meteorological input data, we were

  13. Estimation of Effective Transmission Loss Due to Subtropical Hydrometeor Scatters using a 3D Rain Cell Model for Centimeter and Millimeter Wave Applications

    NASA Astrophysics Data System (ADS)

    Ojo, J. S.; Owolawi, P. A.

    2014-12-01

    The problem of hydrometeor scattering on microwave radio communication down links continues to be of interest as the number of the ground and earth space terminals continually grows The interference resulting from the hydrometeor scattering usually leads to the reduction in the signal-to-noise ratio ( SNR) at the affected terminal and at worst can even end up in total link outage. In this paper, an attempt has been made to compute the effective transmission loss due to subtropical hydrometeors on vertically polarized signals in Earth-satellite propagation paths in the Ku, Ka and V band frequencies based on the modified Capsoni 3D rain cell model. The 3D rain cell model has been adopted and modified using the subtropical log-normal distributions of raindrop sizes and introducing the equivalent path length through rain in the estimation of the attenuation instead of the usual specific attenuation in order to account for the attenuation of both wanted and unwanted paths to the receiver. The co-channels, interference at the same frequency is very prone to the higher amount of unwanted signal at the elevation considered. The importance of joint transmission is also considered.

  14. Calculation of Individual Tree Water Use in a Bornean Tropical Rain Forest Using Individual-Based Dynamic Vegetation Model SEIB-DGVM

    NASA Astrophysics Data System (ADS)

    Nakai, T.; Kumagai, T.; Saito, T.; Matsumoto, K.; Kume, T.; Nakagawa, M.; Sato, H.

    2015-12-01

    Bornean tropical rain forests are among the moistest biomes of the world with abundant rainfall throughout the year, and considered to be vulnerable to a change in the rainfall regime; e.g., high tree mortality was reported in such forests induced by a severe drought associated with the ENSO event in 1997-1998. In order to assess the effect (risk) of future climate change on eco-hydrology in such tropical rain forests, it is important to understand the water use of trees individually, because the vulnerability or mortality of trees against climate change can depend on the size of trees. Therefore, we refined the Spatially Explicit Individual-Based Dynamic Global Vegetation Model (SEIB-DGVM) so that the transpiration and its control by stomata are calculated for each individual tree. By using this model, we simulated the transpiration of each tree and its DBH-size dependency, and successfully reproduced the measured data of sap flow of trees and eddy covariance flux data obtained in a Bornean lowland tropical rain forest in Lambir Hills National Park, Sarawak, Malaysia.

  15. ACID RAIN MODELING

    EPA Science Inventory

    This paper provides an overview of existing statistical methodologies for the estimation of site-specific and regional trends in wet deposition. The interaction of atmospheric processes and emissions tend to produce wet deposition data patterns that show large spatial and tempora...

  16. Scale Dependence of Spatiotemporal Intermittence of Rain

    NASA Technical Reports Server (NTRS)

    Kundu, Prasun K.; Siddani, Ravi K.

    2011-01-01

    It is a common experience that rainfall is intermittent in space and time. This is reflected by the fact that the statistics of area- and/or time-averaged rain rate is described by a mixed distribution with a nonzero probability of having a sharp value zero. In this paper we have explored the dependence of the probability of zero rain on the averaging space and time scales in large multiyear data sets based on radar and rain gauge observations. A stretched exponential fannula fits the observed scale dependence of the zero-rain probability. The proposed formula makes it apparent that the space-time support of the rain field is not quite a set of measure zero as is sometimes supposed. We also give an ex.planation of the observed behavior in tenus of a simple probabilistic model based on the premise that rainfall process has an intrinsic memory.

  17. What Is Acid Rain?

    ERIC Educational Resources Information Center

    Likens, Gene E.

    2004-01-01

    Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

  18. Rain Forest Murals

    ERIC Educational Resources Information Center

    Kleiner, Cheryl

    2010-01-01

    The rain forest murals in the author's school began as a request from her principal to have students decorate the cafeteria with their own paintings. She decided to brainstorm ideas with her eighth-grade students. Taking into consideration the architectural space and the environmental concerns they wanted to convey, students chose the rain forest…

  19. Comprehensive evaluation of multi-satellite precipitation products with a dense rain gauge network and optimally merging their simulated hydrological flows using the Bayesian model averaging method

    NASA Astrophysics Data System (ADS)

    Jiang, Shanhu; Ren, Liliang; Hong, Yang; Yong, Bin; Yang, Xiaoli; Yuan, Fei; Ma, Mingwei

    2012-07-01

    SummaryThis study first focuses on comprehensive evaluating three widely used satellite precipitation products (TMPA 3B42V6, TMPA 3B42RT, and CMORPH) with a dense rain gauge network in the Mishui basin (9972 km2) in South China and then optimally merge their simulated hydrologic flows with the semi-distributed Xinanjiang model using the Bayesian model averaging method. The initial satellite precipitation data comparisons show that the reanalyzed 3B42V6, with a bias of -4.54%, matched best with the rain gauge observations, while the two near real-time satellite datasets (3B42RT and CMORPH) largely underestimated precipitation by 42.72% and 40.81% respectively. With the model parameters first benchmarked by the rain gauge data, the behavior of the streamflow simulation from the 3B42V6 was also the most optimal amongst the three products, while the two near real-time satellite datasets produced deteriorated biases and Nash-Sutcliffe coefficients (NSCEs). Still, when the model parameters were recalibrated by each individual satellite data, the performance of the streamflow simulations from the two near real-time satellite products were significantly improved, thus demonstrating the need for specific calibrations of the hydrological models for the near real-time satellite inputs. Moreover, when optimally merged with respect to the streamflows forced by the two near real-time satellite precipitation products and all the three satellite precipitation products using the Bayesian model averaging method, the resulted streamflow series further improved and became more robust. In summary, the three current state-of-the-art satellite precipitation products have demonstrated potential in hydrological research and applications. The benchmarking, recalibration, and optimal merging schemes for streamflow simulation at a basin scale described in the present work will hopefully be a reference for future utilizations of satellite precipitation products in global and regional

  20. After the Rain: Using the Rain.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  1. Life in Tropical Rain Forests.

    ERIC Educational Resources Information Center

    NatureScope, 1989

    1989-01-01

    Discusses the diversity of rain forest life, the adaptations of rain forest plants and animals, and ways these organisms interact. Includes activities on canopy critters with a copyable sheet, rain forest revue, design a plant, and jungle sleuths. (RT)

  2. Observation and modeling analyses of the macro- and microphysical characteristics of a heavy rain storm in Beijing

    NASA Astrophysics Data System (ADS)

    Guo, Chunwei; Xiao, Hui; Yang, Huiling; Tang, Qi

    2015-04-01

    Beijing and its surrounding areas experienced a heavy rain event from 21 to 22 July 2012. The event can be divided into two phases: a warm-sector precipitation phase, ahead of the cold front, and a cold front precipitation phase. Observational analyses indicated that this rain event resulted from the cooperation of upper- and lower-level weather systems, and also the development and merging of mesoscale convective storm clusters in cumulus-embedded stratus. Simulation results showed that water vapor and hydrometeors transported into Beijing came mainly from the west and south and then exited from the north and east in general. All hydrometeors except ice crystals showed net inflow during the warm-sector phase, while all hydrometeors showed net outflow during the cold front phase overall. The interactions between cold and warm cloud microphysical processes generated the severe precipitation, with melting of graupel into rainwater contributing the most. Cold cloud processes contributed more to rain in the cold front phase compared to that in the warm-sector phase. The general precipitation and hydrometeor precipitation efficiencies were 67.0% and 86.3% in the warm-sector phase, while those in the cold front phase were 44.0% and 74.6%, respectively.

  3. Global precipitation estimates based on a technique for combining satellite-based estimates, rain gauge analysis, and NWP model precipitation information

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Rudolf, Bruno; Schneider, Udo; Keehn, Peter R.

    1995-01-01

    The 'satellite-gauge model' (SGM) technique is described for combining precipitation estimates from microwave satellite data, infrared satellite data, rain gauge analyses, and numerical weather prediction models into improved estimates of global precipitation. Throughout, monthly estimates on a 2.5 degrees x 2.5 degrees lat-long grid are employed. First, a multisatellite product is developed using a combination of low-orbit microwave and geosynchronous-orbit infrared data in the latitude range 40 degrees N - 40 degrees S (the adjusted geosynchronous precipitation index) and low-orbit microwave data alone at higher latitudes. Then the rain gauge analysis is brougth in, weighting each field by its inverse relative error variance to produce a nearly global, observationally based precipitation estimate. To produce a complete global estimate, the numerical model results are used to fill data voids in the combined satellite-gauge estimate. Our sequential approach to combining estimates allows a user to select the multisatellite estimate, the satellite-gauge estimate, or the full SGM estimate (observationally based estimates plus the model information). The primary limitation in the method is imperfections in the estimation of relative error for the individual fields. The SGM results for one year of data (July 1987 to June 1988) show important differences from the individual estimates, including model estimates as well as climatological estimates. In general, the SGM results are drier in the subtropics than the model and climatological results, reflecting the relatively dry microwave estimates that dominate the SGM in oceanic regions.

  4. The process-based stand growth model Formix 3-Q applied in a GIS environment for growth and yield analysis in a tropical rain forest.

    PubMed

    Ditzer, T.; Glauner, R.; Förster, M.; Köhler, P.; Huth, A.

    2000-03-01

    Managing tropical rain forests is difficult because few long-term field data on forest growth and the impact of harvesting disturbance are available. Growth models may provide a valuable tool for managers of tropical forests, particularly if applied to the extended forest areas of up to 100,000 ha that typically constitute the so-called forest management units (FMUs). We used a stand growth model in a geographic information system (GIS) environment to simulate tropical rain forest growth at the FMU level. We applied the process-based rain forest growth model Formix 3-Q to the 55,000 ha Deramakot Forest Reserve (DFR) in Sabah, Malaysia. The FMU was considered to be composed of single and independent small-scale stands differing in site conditions and forest structure. Field data, which were analyzed with a GIS, comprised a terrestrial forest inventory, site and soil analyses (water, nutrients, slope), the interpretation of aerial photographs of the present vegetation and topographic maps. Different stand types were determined based on a classification of site quality (three classes), slopes (four classes), and present forest structure (four strata). The effects of site quality on tree allometry (height-diameter curve, biomass allometry, leaf area) and growth (increment size) are incorporated into Formix 3-Q. We derived allometric relations and growth factors for different site conditions from the field data. Climax forest structure at the stand level was shown to depend strongly on site conditions. Simulated successional pattern and climax structure were compared with field observations. Based on the current management plan for the DFR, harvesting scenarios were simulated for stands on different sites. The effects of harvesting guidelines on forest structure and the implications for sustainable forest management at Deramakot were analyzed. Based on the stand types and GIS analysis, we also simulated undisturbed regeneration of the logged-over forest in the DFR at

  5. Difficult Decisions: Acid Rain.

    ERIC Educational Resources Information Center

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  6. Thinking in the Rain.

    ERIC Educational Resources Information Center

    Bartlett, Albert A.

    1989-01-01

    Four questions related to rain concerning aerodynamic drag force, pressure from the impact of raindrops, impact of wind on the pressure, and stopping force extended on the car by the water are proposed. (YP)

  7. Storm Water Infiltration and Focused Groundwater Recharge in a Rain Garden: Finite Volume Model and Numerical Simulations for Different Configurations and Climates

    NASA Astrophysics Data System (ADS)

    Aravena, J.; Dussaillant, A. R.

    2006-12-01

    Source control is the fundamental principle behind sustainable management of stormwater. Rain gardens are an infiltration practice that provides volume and water quality control, recharge, and multiple landscape, ecological and economic potential benefits. The fulfillment of these objectives requires understanding their behavior during events as well as long term, and tools for their design. We have developed a model based on Richards equation coupled to a surface water balance, solved with a 2D finite volume Fortran code which allows alternating upper boundary conditions, including ponding, which is not present in available 2D models. Also, it can simulate non homogeneous water input, heterogeneous soil (layered or more complex geometries), and surface irregularities -e.g. terracing-, so as to estimate infiltration and recharge. The algorithm is conservative; being an advantage compared to available finite difference and finite element methods. We will present performance comparisons to known models, to experimental data from a bioretention cell, which receives roof water to its surface depression planted with native species in an organic-rich root zone soil layer (underlain by a high conductivity lower layer that, while providing inter-event storage, percolates water readily), as well as long term simulations for different rain garden configurations. Recharge predictions for different climates show significant increases from natural recharge, and that the optimal area ratio (raingarden vs. contributing impervious area) reduces from 20% (humid) to 5% (dry).

  8. A modelling approach to evaluate the long-term effect of soil texture on spring wheat productivity under a rain-fed condition.

    PubMed

    He, Yong; Hou, Lingling; Wang, Hong; Hu, Kelin; McConkey, Brian

    2014-07-30

    Soil surface texture is an important environmental factor that influences crop productivity because of its direct effect on soil water and complex interactions with other environmental factors. Using 30-year data, an agricultural system model (DSSAT-CERES-Wheat) was calibrated and validated. After validation, the modelled yield and water use (WU) of spring wheat (Triticum aestivum L.) from two soil textures (silt loam and clay) under rain-fed condition were analyzed. Regression analysis showed that wheat grown in silt loam soil is more sensitive to WU than wheat grown in clay soil, indicating that the wheat grown in clay soil has higher drought tolerance than that grown in silt loam. Yield variation can be explained by WU other than by precipitation use (PU). These results demonstrated that the DSSAT-CERES-Wheat model can be used to evaluate the WU of different soil textures and assess the feasibility of wheat production under various conditions. These outcomes can improve our understanding of the long-term effect of soil texture on spring wheat productivity in rain-fed condition.

  9. A modelling approach to evaluate the long-term effect of soil texture on spring wheat productivity under a rain-fed condition

    PubMed Central

    He, Yong; Hou, Lingling; Wang, Hong; Hu, Kelin; McConkey, Brian

    2014-01-01

    Soil surface texture is an important environmental factor that influences crop productivity because of its direct effect on soil water and complex interactions with other environmental factors. Using 30-year data, an agricultural system model (DSSAT-CERES-Wheat) was calibrated and validated. After validation, the modelled yield and water use (WU) of spring wheat (Triticum aestivum L.) from two soil textures (silt loam and clay) under rain-fed condition were analyzed. Regression analysis showed that wheat grown in silt loam soil is more sensitive to WU than wheat grown in clay soil, indicating that the wheat grown in clay soil has higher drought tolerance than that grown in silt loam. Yield variation can be explained by WU other than by precipitation use (PU). These results demonstrated that the DSSAT-CERES-Wheat model can be used to evaluate the WU of different soil textures and assess the feasibility of wheat production under various conditions. These outcomes can improve our understanding of the long-term effect of soil texture on spring wheat productivity in rain-fed condition. PMID:25074796

  10. Theoretical Analysis of Rain Attenuation Probability

    NASA Astrophysics Data System (ADS)

    Roy, Surendra Kr.; Jha, Santosh Kr.; Jha, Lallan

    2007-07-01

    Satellite communication technologies are now highly developed and high quality, distance-independent services have expanded over a very wide area. As for the system design of the Hokkaido integrated telecommunications(HIT) network, it must first overcome outages of satellite links due to rain attenuation in ka frequency bands. In this paper theoretical analysis of rain attenuation probability on a slant path has been made. The formula proposed is based Weibull distribution and incorporates recent ITU-R recommendations concerning the necessary rain rates and rain heights inputs. The error behaviour of the model was tested with the loading rain attenuation prediction model recommended by ITU-R for large number of experiments at different probability levels. The novel slant path rain attenuastion prediction model compared to the ITU-R one exhibits a similar behaviour at low time percentages and a better root-mean-square error performance for probability levels above 0.02%. The set of presented models exhibits the advantage of implementation with little complexity and is considered useful for educational and back of the envelope computations.

  11. Presenting the Rain-Sea Interaction Facility

    NASA Technical Reports Server (NTRS)

    Bliven, Larry F.; Elfouhaily, Tonas M.

    1993-01-01

    The new Rain-Sea Interaction Facility (RSIF) was established at GSFC/WFF and the first finds are presented. The unique feature of this laboratory is the ability to systematically study microwave scattering from a water surface roughened by artificial rain, for which the droplets are at terminal velocity. The fundamental instruments and systems (e.g., the rain simulator, scatterometers, and surface elevation probes) were installed and evaluated during these first experiments - so the majority of the data were obtained with the rain simulator at 1 m above the water tank. From these initial experiments, three new models were proposed: the square-root function for NCS vs. R, the log Gaussian model for ring-wave elevation frequency spectrum, and the Erland probability density distribution for back scattered power. Rain rate is the main input for these models, although the coefficients may be dependent upon other factors (drop-size distribution, fall velocity, radar configuration, etc.). The facility is functional and we foresee collaborative studies with investigators who are engaged in measuring and modeling rain-sea interaction processes.

  12. Rain radar instrument definition

    NASA Astrophysics Data System (ADS)

    Vincent, Nicolas; Chenebault, J.; Suinot, Noel; Mancini, Paolo L.

    1996-12-01

    As a result of a pre-phase a study, founded by ESA, this paper presents the definition of a spaceborne Rain Radar, candidate instrument for earth explorer precipitation mission. Based upon the description of user requirements for such a dedicated mission, a mission analysis defines the most suitable space segment. At system level, a parametric analysis compares pros and cons of instrument concepts associated with rain rate retrieval algorithms in order to select the most performing one. Several trade-off analysis at subsystem level leads then to the definition of the proposed design. In particular, as pulse compression is implemented in order to increase the radar sensitivity, the selected method to achieve a pulse response with a side-lobe level below--60 dB is presented. Antenna is another critical rain radar subsystem and several designs are com pared: direct radiating array, single or dual reflector illuminated by single or dual feed arrays. At least, feasibility of centralized amplification using TWTA is compared with criticality of Tx/Rx modules for distributed amplification. Mass and power budgets of the designed instrument are summarized as well as standard deviations and bias of simulated rain rate retrieval profiles. The feasibility of a compliant rain radar instrument is therefore demonstrated.

  13. Energy budget increases reduce mean streamflow more than snow-rain transitions: using integrated modeling to isolate climate change impacts on Rocky Mountain hydrology

    NASA Astrophysics Data System (ADS)

    Foster, Lauren M.; Bearup, Lindsay A.; Molotch, Noah P.; Brooks, Paul D.; Maxwell, Reed M.

    2016-04-01

    In snow-dominated mountain regions, a warming climate is expected to alter two drivers of hydrology: (1) decrease the fraction of precipitation falling as snow; and (2) increase surface energy available to drive evapotranspiration. This study uses a novel integrated modeling approach to explicitly separate energy budget increases via warming from precipitation phase transitions from snow to rain in two mountain headwaters transects of the central Rocky Mountains. Both phase transitions and energy increases had significant, though unique, impacts on semi-arid mountain hydrology in our simulations. A complete shift in precipitation from snow to rain reduced streamflow between 11% and 18%, while 4 °C of uniform warming reduced streamflow between 19% and 23%, suggesting that changes in energy-driven evaporative loss, between 27% and 29% for these uniform warming scenarios, may be the dominant driver of annual mean streamflow in a warming climate. Phase changes induced a flashier system, making water availability more susceptible to precipitation variability and eliminating the runoff signature characteristic of snowmelt-dominated systems. The impact of a phase change on mean streamflow was reduced as aridity increased from west to east of the continental divide.

  14. Sampling Errors in Monthly Rainfall Totals for TRMM and SSM/I, Based on Statistics of Retrieved Rain Rates and Simple Models

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Kundu, Prasun K.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Estimates from TRMM satellite data of monthly total rainfall over an area are subject to substantial sampling errors due to the limited number of visits to the area by the satellite during the month. Quantitative comparisons of TRMM averages with data collected by other satellites and by ground-based systems require some estimate of the size of this sampling error. A method of estimating this sampling error based on the actual statistics of the TRMM observations and on some modeling work has been developed. "Sampling error" in TRMM monthly averages is defined here relative to the monthly total a hypothetical satellite permanently stationed above the area would have reported. "Sampling error" therefore includes contributions from the random and systematic errors introduced by the satellite remote sensing system. As part of our long-term goal of providing error estimates for each grid point accessible to the TRMM instruments, sampling error estimates for TRMM based on rain retrievals from TRMM microwave (TMI) data are compared for different times of the year and different oceanic areas (to minimize changes in the statistics due to algorithmic differences over land and ocean). Changes in sampling error estimates due to changes in rain statistics due 1) to evolution of the official algorithms used to process the data, and 2) differences from other remote sensing systems such as the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I), are analyzed.

  15. Estimating Rain Rates from Tipping-Bucket Rain Gauge Measurements

    NASA Technical Reports Server (NTRS)

    Wang, Jianxin; Fisher, Brad L.; Wolff, David B.

    2007-01-01

    This paper describes the cubic spline based operational system for the generation of the TRMM one-minute rain rate product 2A-56 from Tipping Bucket (TB) gauge measurements. Methodological issues associated with applying the cubic spline to the TB gauge rain rate estimation are closely examined. A simulated TB gauge from a Joss-Waldvogel (JW) disdrometer is employed to evaluate effects of time scales and rain event definitions on errors of the rain rate estimation. The comparison between rain rates measured from the JW disdrometer and those estimated from the simulated TB gauge shows good overall agreement; however, the TB gauge suffers sampling problems, resulting in errors in the rain rate estimation. These errors are very sensitive to the time scale of rain rates. One-minute rain rates suffer substantial errors, especially at low rain rates. When one minute rain rates are averaged to 4-7 minute or longer time scales, the errors dramatically reduce. The rain event duration is very sensitive to the event definition but the event rain total is rather insensitive, provided that the events with less than 1 millimeter rain totals are excluded. Estimated lower rain rates are sensitive to the event definition whereas the higher rates are not. The median relative absolute errors are about 22% and 32% for 1-minute TB rain rates higher and lower than 3 mm per hour, respectively. These errors decrease to 5% and 14% when TB rain rates are used at 7-minute scale. The radar reflectivity-rainrate (Ze-R) distributions drawn from large amount of 7-minute TB rain rates and radar reflectivity data are mostly insensitive to the event definition.

  16. Rain sampling device

    DOEpatents

    Nelson, Danny A.; Tomich, Stanley D.; Glover, Donald W.; Allen, Errol V.; Hales, Jeremy M.; Dana, Marshall T.

    1991-01-01

    The present invention constitutes a rain sampling device adapted for independent operation at locations remote from the user which allows rainfall to be sampled in accordance with any schedule desired by the user. The rain sampling device includes a mechanism for directing wet precipitation into a chamber, a chamber for temporarily holding the precipitation during the process of collection, a valve mechanism for controllably releasing samples of said precipitation from said chamber, a means for distributing the samples released from the holding chamber into vessels adapted for permanently retaining these samples, and an electrical mechanism for regulating the operation of the device.

  17. Rain sampling device

    DOEpatents

    Nelson, D.A.; Tomich, S.D.; Glover, D.W.; Allen, E.V.; Hales, J.M.; Dana, M.T.

    1991-05-14

    The present invention constitutes a rain sampling device adapted for independent operation at locations remote from the user which allows rainfall to be sampled in accordance with any schedule desired by the user. The rain sampling device includes a mechanism for directing wet precipitation into a chamber, a chamber for temporarily holding the precipitation during the process of collection, a valve mechanism for controllably releasing samples of the precipitation from the chamber, a means for distributing the samples released from the holding chamber into vessels adapted for permanently retaining these samples, and an electrical mechanism for regulating the operation of the device. 11 figures.

  18. The role of convection permitting modeling to evaluate the contribution of the anthropogenic climate change on the UK Winter 2013-2014 extreme rain

    NASA Astrophysics Data System (ADS)

    Omrani, Hiba; Vautard, Robert

    2016-04-01

    During the winter 2013/2014, the UK saw heavy rainfalls associated with a succession of storms reaching Southern England causing widespread flooding, power cuts and major disruptions to transport. The January precipitation set a record for several rain gauge stations in Southern England. The aim of this study is to evaluate the contribution of the anthropogenic climate change, represented by a modification of the sea surface temperature (SST) on the January precipitation. For that, we conducted a sensitivity experiment by running a set of two-months simulations using WRF model with 50km horizontal resolution simulation and 2 km convection permitting simulation centered over the southern UK. We also investigated the sensitivity to the model physics. Results show that the horizontal resolution plays an important role for interpreting the results. Indeed, the low resolution simulation showed no robust signal to attribute this event. However, the convection permitting simulations gave more consistent results over the studied area.

  19. Influence of rain gauge network density on flood model prediction: a statistical investigation using synthetic rainfall fields on basins of different size and a comparison with a real case

    NASA Astrophysics Data System (ADS)

    Seoni, Alessandro; Deidda, Roberto

    2014-05-01

    The accuracy of simulation of the catchment hydrologic response is strongly affected by the reliable representation of the spatial rainfall pattern. The present work investigates the role of rainfall sampling and network density on the performance of a lumped and a distributed rainfall-runoff model in predicting extreme floods. The analysis is conducted on a suite of 12 basins of different size ranging from 15 to 1793 km2 , located in Sardinia, Italy. In order to create a reference framework uncorrupted by errors of measure and of modelling, we assume as reference precipitation an high resolution rainfall field (1.5 km x 1.5 km x 5 min, 80 years long) derived through a downscaling procedure, and as reference discharge the corresponding hydrograph obtained by the two rainfall-runoff models. In order to investigate the sensitivity of the hydrological response to the rain gauge network density we assume that a rainfall series from a single cell (1.5 km x 1.5 km) is equivalent to a potential fictitious rain gauge record and consequently we activate a number of potential gauges ranging from 1 up to 30 (for each considered basin). Then for each fixed network size, we randomly select 100 independent spatial combinations of rain gauge positions providing the rainfall pattern scenarios which are used as input of the two rainfall-runoff models to produce an ensemble of 100 corresponding discharge scenarios. Performances are evaluated by comparing the discharge scenarios (obtained by a limited number of potential rain gauges) with the reference discharge (obtained by the entire high resolution rainfall fields) and applying different metrics. A critical analysis of the advantage of using distributed vs lumped modelling is performed considering: model performance variability related to the number of rain gauges; model performance dependence on event magnitude; minimum number of rain gauges for a satisfying model performance and its relationship with event magnitude; dependence

  20. Rain-rate data base development and rain-rate climate analysis

    NASA Technical Reports Server (NTRS)

    Crane, Robert K.

    1993-01-01

    The single-year rain-rate distribution data available within the archives of Consultative Committee for International Radio (CCIR) Study Group 5 were compiled into a data base for use in rain-rate climate modeling and for the preparation of predictions of attenuation statistics. The four year set of tip-time sequences provided by J. Goldhirsh for locations near Wallops Island were processed to compile monthly and annual distributions of rain rate and of event durations for intervals above and below preset thresholds. A four-year data set of tropical rain-rate tip-time sequences were acquired from the NASA TRMM program for 30 gauges near Darwin, Australia. They were also processed for inclusion in the CCIR data base and the expanded data base for monthly observations at the University of Oklahoma. The empirical rain-rate distributions (edfs) accepted for inclusion in the CCIR data base were used to estimate parameters for several rain-rate distribution models: the lognormal model, the Crane two-component model, and the three parameter model proposed by Moupfuma. The intent of this segment of the study is to obtain a limited set of parameters that can be mapped globally for use in rain attenuation predictions. If the form of the distribution can be established, then perhaps available climatological data can be used to estimate the parameters rather than requiring years of rain-rate observations to set the parameters. The two-component model provided the best fit to the Wallops Island data but the Moupfuma model provided the best fit to the Darwin data.

  1. Impact of Cloud Model Microphysics on Passive Microwave Retrievals of Cloud Properties. Part II: Uncertainty in Rain, Hydrometeor Structure, and Latent Heating Retrievals

    NASA Astrophysics Data System (ADS)

    Seo, Eun-Kyoung; Biggerstaff, Michael I.

    2006-07-01

    The impact of model microphysics on the retrieval of cloud properties based on passive microwave observations was examined using a three-dimensional, nonhydrostatic, adaptive-grid cloud model to simulate a mesoscale convective system over ocean. Two microphysical schemes, based on similar bulk two-class liquid and three-class ice parameterizations, were used to simulate storms with differing amounts of supercooled cloud water typical of both the tropical oceanic environment, in which there is little supercooled cloud water, and midlatitude continental environments in which supercooled cloud water is more plentiful. For convective surface-level rain rates, the uncertainty varied between 20% and 60% depending on which combination of passive and active microwave observations was used in the retrieval. The uncertainty in surface rain rate did not depend on the microphysical scheme or the parameter settings except for retrievals over stratiform regions based on 85-GHz brightness temperatures TB alone or 85-GHz TB and radar reflectivity combined. In contrast, systematic differences in the treatment of the production of cloud water, cloud ice, and snow between the parameterization schemes coupled with the low correlation between those properties and the passive microwave TB examined here led to significant differences in the uncertainty in retrievals of those cloud properties and latent heating. The variability in uncertainty of hydrometeor structure and latent heating associated with the different microphysical parameterizations exceeded the inherent variability in TB cloud property relations. This was true at the finescales of the cloud model as well as at scales consistent with satellite footprints in which the inherent variability in TB cloud property relations are reduced by area averaging.

  2. Rain Forests: Tropical Treasures.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1989-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Rain Forests: Tropical Treasures." Contents are organized into the…

  3. The Acid Rain Debate.

    ERIC Educational Resources Information Center

    Oates-Bockenstedt, Catherine

    1997-01-01

    Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

  4. Acid Rain Investigations.

    ERIC Educational Resources Information Center

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  5. Acid Rain Classroom Projects.

    ERIC Educational Resources Information Center

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  6. The Acid Rain Debate.

    ERIC Educational Resources Information Center

    Bybee, Rodger; And Others

    1984-01-01

    Describes an activity which provides opportunities for role-playing as industrialists, ecologists, and government officials. The activity involves forming an international commission on acid rain, taking testimony, and, based on the testimony, making recommendations to governments on specific ways to solve the problem. Includes suggestions for…

  7. Acid rain bibliography

    SciTech Connect

    Sayers, C.S.

    1983-09-01

    This bibliography identifies 900 citations on various aspects of Acid Rain, covering published bibliographies, books, reports, conference and symposium proceedings, audio visual materials, pamphlets and newsletters. It includes five sections: citations index (complete record of author, title, source, order number); KWIC index; title index; author index; and source index. 900 references.

  8. Rain Forest Dance Residency.

    ERIC Educational Resources Information Center

    Watson, Dawn

    1997-01-01

    Outlines the author's experience as a dancer and choreographer artist-in-residence with third graders at a public elementary school, providing a cultural arts experience to tie in with a theme study of the rain forest. Details the residency and the insights she gained working with students, teachers, and theme. (SR)

  9. Slouching in the Rain

    ERIC Educational Resources Information Center

    Bailey, Herb

    2013-01-01

    A number of papers find the velocity that minimizes the wetness of a traveler caught in the rain. In this capsule we determine, in addition, the necessary amount of forward bend (slouching) so that the traveler stays as dry as possible.

  10. Acid rain sourcebook

    SciTech Connect

    Elliott, T.C.; Schwieger, R.G.

    1984-01-01

    Discusses the problem of acid rain and how it can be controlled. The book is divided into seven key sections: the problem and the legislative solutions; international mitigation programs; planning the US program; emissions reduction-before combustion; emissions/reduction-during combustion; emissions reduction-after combustion and engineering solutions under development. 13 papers have been abstracted separately.

  11. The acid rain sourcebook

    SciTech Connect

    Elliott, T.C.; Schwieger, R.G.

    1985-01-01

    A reference collection of specialized information discussions on areas critical to the acid rain issue: problem definition, impact of legislation, emissions standards, international perspective, cost scenarios, and engineering solutions. The text is reinforced with 130 illustrations and about 50 tables. Contents: International mitigation programs. Emissions reduction: before combustion; during combustion; after combustion. Engineering solutions under development.

  12. After the Rain: Clouds.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  13. After the Rain: Rainbows.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  14. After the Rain: Dryspell.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  15. After the Rain: Animals.

    ERIC Educational Resources Information Center

    Old Elk, Arlene; Stoklas, Jackie

    The Heard Museum (Phoenix, Arizona) has developed and updated an integrated curriculum for use in grades K-3. The goals for this curriculum are to: (1) share museum resources with schools; (2) promote cross-cultural understanding through a focus on rain, a universal requirement for life; (3) help students understand that Native Americans are…

  16. Rain Drop Charge Sensor

    NASA Astrophysics Data System (ADS)

    S, Sreekanth T.

    begin{center} Large Large Rain Drop Charge Sensor Sreekanth T S*, Suby Symon*, G. Mohan Kumar (1) , S. Murali Das (2) *Atmospheric Sciences Division, Centre for Earth Science Studies, Thiruvananthapuram 695011 (1) D-330, Swathi Nagar, West Fort, Thiruvananthapuram 695023 (2) Kavyam, Manacaud, Thiruvananthapuram 695009 begin{center} ABSTRACT To study the inter-relations with precipitation electricity and precipitation microphysical parameters a rain drop charge sensor was designed and developed at CESS Electronics & Instrumentation Laboratory. Simultaneous measurement of electric charge and fall speed of rain drops could be done using this charge sensor. A cylindrical metal tube (sensor tube) of 30 cm length is placed inside another thick metal cover opened at top and bottom for electromagnetic shielding. Mouth of the sensor tube is exposed and bottom part is covered with metal net in the shielding cover. The instrument is designed in such a way that rain drops can pass only through unhindered inside the sensor tube. When electrically charged rain drops pass through the sensor tube, it is charged to the same magnitude of drop charge but with opposite polarity. The sensor tube is electrically connected the inverted input of a current to voltage converter operational amplifier using op-amp AD549. Since the sensor is electrically connected to the virtual ground of the op-amp, the charge flows to the ground and the generated current is converted to amplified voltage. This output voltage is recorded using a high frequency (1kHz) voltage recorder. From the recorded pulse, charge magnitude, polarity and fall speed of rain drop are calculated. From the fall speed drop diameter also can be calculated. The prototype is now under test running at CESS campus. As the magnitude of charge in rain drops is an indication of accumulated charge in clouds in lightning, this instrument has potential application in the field of risk and disaster management. By knowing the charge

  17. Torrential Rain in China

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Concentric ovals of red, orange, yellow, and green are draped over southern China, showing rainfall totals for the week of June 4 through June 11, 2007. The rainfall totals are from the Goddard Space Flight Center Multi-satellite Precipitation Analysis, which is based on rainfall measurements taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. Though seasonal rains are not unexpected in the area, the rain that fell during the week was torrential and relentless. As the image shows, a broad stretch of China received up to 200 millimeters (8 inches) of rain, and some areas were inundated with up to 500 millimeters (20 inches). Floods and landslides resulted, destroying crops and forcing some 643,000 people from their homes, reported the Xinhua News Agency on ReliefWeb. As of June 11, 71 people had died and 13 were missing. The most affected area was the southern coast, where rainfall totals are highest in this image. Heavy tropical rains combined with steep mountains make southeastern China prone to devastating landslides. Monitoring landslide-producing conditions typically requires extensive networks of ground-based rain gauges and weather instruments. But many developing countries in high-risk areas lack the resources to maintain such systems; heavy rains and flooding often wash away ground-based instruments. Robert Adler, a senior scientist in the Laboratory for Atmospheres at Goddard Space Flight Center, and Yang Hong, a research scientist at Goddard Earth Sciences Technology Center, are confronting the problem by developing a satellite-based system for predicting landslides. The system relies on TRMM data to predict when rainfall in different areas has reached a landslide-triggering threshold. The system makes data available on the Internet just a few hours after the satellite makes its observations. To read more about the landslide-monitoring system, please read the feature article Satellite Monitors Rains That Trigger Landslides, http

  18. Estimation of Rain Intensity Spectra over the Continental US Using Ground Radar-Gauge Measurements

    NASA Technical Reports Server (NTRS)

    Lin, Xin; Hou, Arthur Y.

    2013-01-01

    A high-resolution surface rainfall product is used to estimate rain characteristics over the continental US as a function of rain intensity. By defining each data at 4-km horizontal resolutions and 1-h temporal resolutions as an individual precipitating/nonprecipitating sample, statistics of rain occurrence and rain volume including their geographical and seasonal variations are documented. Quantitative estimations are also conducted to evaluate the impact of missing light rain events due to satellite sensors' detection capabilities. It is found that statistics of rain characteristics have large seasonal and geographical variations across the continental US. Although heavy rain events (> 10 mm/hr.) only occupy 2.6% of total rain occurrence, they may contribute to 27% of total rain volume. Light rain events (< 1.0 mm/hr.), occurring much more frequently (65%) than heavy rain events, can also make important contributions (15%) to the total rain volume. For minimum detectable rain rates setting at 0.5 and 0.2 mm/hr which are close to sensitivities of the current and future space-borne precipitation radars, there are about 43% and 11% of total rain occurrence below these thresholds, and they respectively represent 7% and 0.8% of total rain volume. For passive microwave sensors with their rain pixel sizes ranging from 14 to 16 km and the minimum detectable rain rates around 1 mm/hr., the missed light rain events may account for 70% of train occurrence and 16% of rain volume. Statistics of rain characteristics are also examined on domains with different temporal and spatial resolutions. Current issues in estimates of rain characteristics from satellite measurements and model outputs are discussed.

  19. When It Rains, It Pours

    ERIC Educational Resources Information Center

    Mills, Linda

    2012-01-01

    "It's raining, it's pouring, the old man is snoring!" "The itsy, bitsy spider crawled up the waterspout, down came the rain and washed the spider out. Out came the sun and dried up all the rain, and the itsy, bitsy spider went up the spout again." What do children's nursery rhymes have to do with the school library? The author begins by telling a…

  20. Lessons from the Rain Forest.

    ERIC Educational Resources Information Center

    Phillips, Shelley

    2002-01-01

    Presents a first-grade art project after students learned about the rain forest and heard the story, "The Great Kapok Tree: A Tale of the Amazon Rain Forest" (Lynn Cherry). Explains that the students created pictures of the rain forest. (CMK)

  1. Data set: A modeling dataset that spans the rain - snow transition zone: Johnston Draw catchment, Reynolds Creek Experimental Watershed, Idaho, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrometeorological data from the rain-to-snow transition zone in mountain basins are limited. As the climate warms, the transition from rain to snow in mountain regions is moving to higher elevations, and these changes are altering the timing of water delivery to the downstream streams, lakes and w...

  2. Rainfall estimates for hydrological models: Comparing rain gauge, radar and microwave link data as input for the Wageningen Lowland Runoff Simulator (WALRUS)

    NASA Astrophysics Data System (ADS)

    Brauer, Claudia; Overeem, Aart; Uijlenhoet, Remko

    2015-04-01

    Several rainfall measurement techniques are available for hydrological applications, each with its own spatial and temporal resolution. We investigated the effect of differences in rainfall estimates on discharge simulations in a lowland catchment by forcing a novel rainfall-runoff model (WALRUS) with rainfall data from gauges, radars and microwave links. The hydrological model used for this analysis is the recently developed Wageningen Lowland Runoff Simulator (WALRUS). WALRUS is a rainfall-runoff model accounting for hydrological processes relevant to areas with shallow groundwater (e.g. groundwater-surface water feedback). Here, we used WALRUS for case studies in the Hupsel Brook catchment. We used two automatic rain gauges with hourly resolution, located inside the catchment (the base run) and 30 km northeast. Operational (real-time) and climatological (gauge-adjusted) C-band radar products and country-wide rainfall maps derived from microwave link data from a cellular telecommunication network were also used. Discharges simulated with these different inputs were compared to observations. Traditionally, the precipitation research community places emphasis on quantifying spatial errors and uncertainty, but for hydrological applications, temporal errors and uncertainty should be quantified as well. Its memory makes the hydrologic system sensitive to missed or badly timed rainfall events, but also emphasizes the effect of a bias in rainfall estimates. Systematic underestimation of rainfall by the uncorrected operational radar product leads to very dry model states and an increasing underestimation of discharge. Using the rain gauge 30 km northeast of the catchment yields good results for climatological studies, but not for forecasting individual floods. Simulating discharge using the maps derived from microwave link data and the gauge-adjusted radar product yields good results for both events and climatological studies. This indicates that these products can be

  3. SNP-Based QTL Mapping of 15 Complex Traits in Barley under Rain-Fed and Well-Watered Conditions by a Mixed Modeling Approach.

    PubMed

    Mora, Freddy; Quitral, Yerko A; Matus, Ivan; Russell, Joanne; Waugh, Robbie; Del Pozo, Alejandro

    2016-01-01

    This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5-22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5-35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint.

  4. SNP-Based QTL Mapping of 15 Complex Traits in Barley under Rain-Fed and Well-Watered Conditions by a Mixed Modeling Approach

    PubMed Central

    Mora, Freddy; Quitral, Yerko A.; Matus, Ivan; Russell, Joanne; Waugh, Robbie; del Pozo, Alejandro

    2016-01-01

    This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5–22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5–35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint. PMID:27446139

  5. The politics of acid rain

    SciTech Connect

    Wilcher, M.E. )

    1989-01-01

    This work examines and compares the acid rain policies through the different political systems of Canada, Great Britain and the United States. Because the flow of acid rain can transcend national boundaries, acid rain has become a crucial international problem. According to the author, because of differences in governmental institutions and structure, the extent of governmental intervention in the industrial economy, the degree of reliance on coal for power generation, and the extent of acid rain damage, national responses to the acid rain problem have varied.

  6. Rain erosion considerations for launch vehicle insulation systems

    NASA Technical Reports Server (NTRS)

    Daniels, D. J.; Sieker, W. D.

    1977-01-01

    In recent years the Delta launch vehicle has incorporated the capability to be launched through rain. This capability was developed to eliminate a design constraint which could result in a costly launch delay. This paper presents the methodology developed to implement rain erosion protection for the insulated exterior vehicle surfaces. The effect of the interaction between insulation material rain erosion resistance, rainstorm models, surface geometry and trajectory variations is examined. It is concluded that rain erosion can significantly impact the performance of launch vehicle insulation systems and should be considered in their design.

  7. Estimating rainfall in the tropics using the fractional time raining

    NASA Technical Reports Server (NTRS)

    Morrissey, Mark L.; Krajewski, Witold F.; Mcphaden, Michael J.

    1994-01-01

    The relationship between the fractional time raining and tropical rainfall amount is investigated using raingage data and a point process model of tropical rainfall. Both the strength and the nature of the relationship are dependent upon the resolution of the data used to estimate the fractional time raining. It is found that highly accurate estimates of rainfall amounts over periods of one month or greater can be obtained from the fractional time raining so long as high-time-resolution data are used. It is demonstrated that the relationship between the fractional time raining and monthly atoll rainfall is quasi-homogeneous within the monsoon trough region of the equatorial western Pacific.

  8. Mechanics of interrill erosion with wind-driven rain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The vector physics of wind-driven rain (WDR) differs from that of wind-free rain, and the interrill soil detachment equations in the Water Erosion Prediction Project (WEPP) model were not originally developed to deal with this phenomenon. This article provides an evaluation of the performance of the...

  9. Rain attenuation statistics over millimeter wave bands in South Korea

    NASA Astrophysics Data System (ADS)

    Shrestha, Sujan; Choi, Dong-You

    2017-01-01

    Rain induced degradations are significant for terrestrial microwave links operating at frequencies higher than 10 GHz. Paper presents analyses done on rain attenuation and rainfall data for three years between 2013 till 2015, in 3.2 km experimental link of 38 GHz and 0.1 km link at 75 GHz. The less link distance is maintained for 75 GHz operating frequency in order to have better recording of propagation effect as such attenuation induced by rain. OTT Parsivel is used for collection of rain rate database which show rain rate of about 50 mm/h and attenuation values of 20.89 and 28.55 dB are obtained at 0.01% of the time for vertical polarization under 38 and 75 GHz respectively. Prediction models, namely, ITU-R P. 530-16, Da Silva Mello, Moupfouma, Abdulrahman, Lin and differential equation approach are analyzed. This studies help to identify most suitable rain attenuation model for higher microwave bands. While applying ITU-R P. 530-16, the relative error margin of about 3%, 38% and 42% along with 80, 70, 61% were obtained in 0.1%, 0.01% and 0.001% of the time for vertical polarization under 38 and 75 GHz respectively. Interestingly, ITU-R P. 530-16 shows relatively closer estimation to measured rain attenuation at 75 GHz with relatively less error probabilities and additionally, Abdulrahman and ITU-R P. 530-16 results in better estimation to the measured rain attenuation at 38 GHz link. The performance of prominent rain attenuation models are judged with different error matrices as recommended by ITU-R P. 311-15. Furthermore, the efficacy of frequency scaling technique of rain attenuation between links distribution are also discussed. This study shall be useful for making good considerations in rain attenuation predictions for terrestrial link operating at higher frequencies.

  10. Using an extended 2D hydrodynamic model for evaluating damage risk caused by extreme rain events: Flash-Flood-Risk-Map (FFRM) Upper Austria

    NASA Astrophysics Data System (ADS)

    Humer, Günter; Reithofer, Andreas

    2016-04-01

    Using an extended 2D hydrodynamic model for evaluating damage risk caused by extreme rain events: Flash-Flood-Risk-Map (FFRM) Upper Austria Considering the increase in flash flood events causing massive damage during the last years in urban but also rural areas [1-4], the requirement for hydrodynamic calculation of flash flood prone areas and possible countermeasures has arisen to many municipalities and local governments. Besides the German based URBAS project [1], also the EU-funded FP7 research project "SWITCH-ON" [5] addresses the damage risk caused by flash floods in the sub-project "FFRM" (Flash Flood Risk Map Upper Austria) by calculating damage risk for buildings and vulnerable infrastructure like schools and hospitals caused by flash-flood driven inundation. While danger zones in riverine flooding are established as an integral part of spatial planning, flash floods caused by overland runoff from extreme rain events have been for long an underrated safety hazard not only for buildings and infrastructure, but man and animals as well. Based on the widespread 2D-model "hydro_as-2D", an extension was developed, which calculates the runoff formation from a spatially and temporally variable precipitation and determines two dimensionally the land surface area runoff and its concentration. The conception of the model is to preprocess the precipitation data and calculate the effective runoff-volume for a short time step of e.g. five minutes. This volume is applied to the nodes of the 2D-model and the calculation of the hydrodynamic model is started. At the end of each time step, the model run is stopped, the preprocessing step is repeated and the hydraulic model calculation is continued. In view of the later use for the whole of Upper Austria (12.000 km²) a model grid of 25x25 m² was established using digital elevation data. Model parameters could be estimated for the small catchment of river Ach, which was hit by an intense rain event with up to 109 mm per hour

  11. Remote sensing of rain over the ocean

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Computer models of the microwave emission from the earth's atmosphere were used to study the problem of retrieving meteorological information from the SMMR instrument that will be flown on NIMBUS-G. Methods for retrieving rain rate, wind speed, cloud height, and ocean temperature are described for the case when the satellite is over the ocean.

  12. A Summary of Scatterometer Returns from Water Surfaces Agitated by Rain

    NASA Technical Reports Server (NTRS)

    Bliven, Larry F.; Giovanangeli, Jean-Paul; Branger, Hubert; Sobieski, Piotr W.

    1997-01-01

    In this paper, we summarize our initial findings from K(a)- and K(u)-band scatterometers which include: a scaling law for backscattered power as a function of rain rate; a linear superposition model for light rains and low wind speeds; evidence of the importance of scattering from rain-generated ring-waves; and progress towards development of a scattering model for computing normalized radar cross sections from wind and rain roughened water surfaces.

  13. Rain and deicing experiments in a wind tunnel

    NASA Technical Reports Server (NTRS)

    Fasso, G.

    1983-01-01

    Comments on films of tests simulating rain and ice conditions in a wind tunnel are presented, with the aim of studying efficient methods of overcoming the adverse effects of rain and ice on aircraft. In the experiments, lifesize models and models of the Mirave 4 aircraft were used. The equipment used to simulate rain and ice is described. Different configurations of landing and takeoff under conditions of moderate or heavy rain at variable angles of incidence and of skipping and at velocities varying from 30 to 130 m/sec are reproduced in the wind tunnel. The risks of erosion of supersonic aircraft by the rain during the loitering and approach phases are discussed.

  14. Rainfall-runoff modelling by using SM2RAIN-derived and state-of-the-art satellite rainfall products over Italy

    NASA Astrophysics Data System (ADS)

    Ciabatta, Luca; Brocca, Luca; Massari, Christian; Moramarco, Tommaso; Gabellani, Simone; Puca, Silvia; Wagner, Wolfgang

    2016-06-01

    Satellite rainfall products (SRPs) are becoming more accurate with ever increasing spatial and temporal resolution. This evolution can be beneficial for hydrological applications, providing new sources of information and allowing to drive models in ungauged areas. Despite the large availability of rainfall satellite data, their use in rainfall-runoff modelling is still very scarce, most likely due to measurement issues (bias, accuracy) and the hydrological community acceptability of satellite products. In this study, the real-time version (3B42-RT) of Tropical Rainfall Measurement Mission Multi-satellite Precipitation Analysis, TMPA, and a new SRP based on the application of SM2RAIN algorithm (Brocca et al., 2014) to the ASCAT (Advanced SCATterometer) soil moisture product, SM2RASC, are used to drive a lumped hydrologic model over four basins in Italy during the 4-year period 2010-2013. The need of the recalibration of model parameter values for each SRP is highlighted, being an important precondition for their suitable use in flood modelling. Results shows that SRPs provided, in most of the cases, performance scores only slightly lower than those obtained by using observed data with a reduction of Nash-Sutcliffe efficiency (NS) less than 30% when using SM2RASC product while TMPA is characterized by a significant deterioration during the validation period 2012-2013. Moreover, the integration between observed and satellite rainfall data is investigated as well. Interestingly, the simple integration procedure here applied allows obtaining more accurate rainfall input datasets with respect to the use of ground observations only, for 3 out 4 basins. Indeed, discharge simulations improve when ground rainfall observations and SM2RASC product are integrated, with an increase of NS between 2 and 42% for the 3 basins in Central and Northern Italy. Overall, the study highlights the feasibility of using SRPs in hydrological applications over the Mediterranean region with

  15. Spatial Analysis of Weather-induced Annual and Decadal Average Yield Variability as Modeled by EPIC for Rain-fed Wheat in Europe

    NASA Astrophysics Data System (ADS)

    Khabarov, Nikolay; Balkovic, Juraj; Schmid, Erwin; Schwartz, Alexander; Obersteiner, Michael; Azevedo, Ligia B.

    2016-04-01

    In our analysis we evaluate the accuracy of near-term (decadal) average crop yield assessments as supported by the biophysical crop growth model EPIC. A spatial assessment of averages and variability has clear practical implications for agricultural producers and investors concerned with an estimation of the basic stochastic characteristics of a crop yield distribution. As a reliable weather projection for a time period of several years will apparently remain a challenge in the near future, we have employed the existing gridded datasets on historical weather as a best proxy for the current climate. Based on different weather inputs to EPIC, we analyzed the model runs for the rain-fed wheat for 1968-2007 employing AgGRID/GGCMI simulations using harmonized inputs and assumptions (weather datasets: GRASP and Princeton). We have explored the variability of historical ten-year yield averages in the past forty years as modeled by the EPIC model, and found that generally the ten-year average yield variability is less than 20% ((max-min)/average), whereas there are mid/low yielding areas with a higher ten-years average variability of 20-50%. The location of these spots of high variability differs between distinctive model-weather setups. Assuming that historical weather can be used as a proxy of the weather in the next ten years, a best possible EPIC-based assessment of a ten-year average yield is a range of 20% width ((max-min)/average). For some mid/low productive areas the range is up to 50% wide.

  16. A Robust, Microwave Rain Gauge

    NASA Astrophysics Data System (ADS)

    Mansheim, T. J.; Niemeier, J. J.; Kruger, A.

    2008-12-01

    Researchers at The University of Iowa have developed an all-electronic rain gauge that uses microwave sensors operating at either 10 GHz or 23 GHz, and measures the Doppler shift caused by falling raindrops. It is straightforward to interface these sensors with conventional data loggers, or integrate them into a wireless sensor network. A disadvantage of these microwave rain gauges is that they consume significant power when they are operating. However, this may be partially negated by using data loggers' or sensors networks' sleep-wake-sleep mechanism. Advantages of the microwave rain gauges are that one can make them very robust, they cannot clog, they don't have mechanical parts that wear out, and they don't have to be perfectly level. Prototype microwave rain gauges were collocated with tipping-bucket rain gauges, and data were collected for two seasons. At higher rain rates, microwave rain gauge measurements compare well with tipping-bucket measurements. At lower rain rates, the microwave rain gauges provide more detailed information than tipping buckets, which quantize measurement typically in 1 tip per 0.01 inch, or 1 tip per mm of rainfall.

  17. Comparing statistical and process-based flow duration curve models in ungauged basins and changing rain regimes

    NASA Astrophysics Data System (ADS)

    Müller, M. F.; Thompson, S. E.

    2016-02-01

    The prediction of flow duration curves (FDCs) in ungauged basins remains an important task for hydrologists given the practical relevance of FDCs for water management and infrastructure design. Predicting FDCs in ungauged basins typically requires spatial interpolation of statistical or model parameters. This task is complicated if climate becomes non-stationary, as the prediction challenge now also requires extrapolation through time. In this context, process-based models for FDCs that mechanistically link the streamflow distribution to climate and landscape factors may have an advantage over purely statistical methods to predict FDCs. This study compares a stochastic (process-based) and statistical method for FDC prediction in both stationary and non-stationary contexts, using Nepal as a case study. Under contemporary conditions, both models perform well in predicting FDCs, with Nash-Sutcliffe coefficients above 0.80 in 75 % of the tested catchments. The main drivers of uncertainty differ between the models: parameter interpolation was the main source of error for the statistical model, while violations of the assumptions of the process-based model represented the main source of its error. The process-based approach performed better than the statistical approach in numerical simulations with non-stationary climate drivers. The predictions of the statistical method under non-stationary rainfall conditions were poor if (i) local runoff coefficients were not accurately determined from the gauge network, or (ii) streamflow variability was strongly affected by changes in rainfall. A Monte Carlo analysis shows that the streamflow regimes in catchments characterized by frequent wet-season runoff and a rapid, strongly non-linear hydrologic response are particularly sensitive to changes in rainfall statistics. In these cases, process-based prediction approaches are favored over statistical models.

  18. Coupled atmospheric-hydrological modelling of the Canadian Rockies rain-on-snow flood of June 2013

    NASA Astrophysics Data System (ADS)

    Pietroniro, A.; Davison, B.; Fortin, V.

    2014-12-01

    Over the last several years there has been some convergence in both atmospheric and hydrological sciences in the application of coupled atmospheric-hydrological modelling systems. In Canada the result of many years of research in academic and government facilities resulted in a prototype hydrology land-surface modelling system know as MESH. Following the devastating floods in Calgary which occurred July 2013, Environment Canada has re-evaluated it modelling systems to look at the ability provide guidance to our partner agencies at the national scale by building upon existing Numerical Weather Prediction technology (NWP) developed largely for weather forecasting applications. The development of these types of guidance systems will rely mainly on the Canadian Precipitation Analysis system (CaPA), the Canadian Land Data Assimilation system (CaLDAS) and the deterministic weather prediction system using the GEM atmospheric model and grund-based real-time flow observations. Preliminary results of our MESH land-surface hydrology scheme forced by GEM forecasted precipitation were evaluated for the specific flood event in and around the headwaters of the Eastern flowing tributaries of the Rocky Mountains. Discussion on model performance, calibration of important water balance and routing parameters along with the feasibility of operationalizing these systems with real-time observational networks is discussed.

  19. A model of rapid preferential hillslope runoff contributions to peak flow generation in a temperate rain forest watershed

    NASA Astrophysics Data System (ADS)

    Beckers, Jos; Alila, Younes

    2004-03-01

    A model for the 10 km2 Carnation Creek watershed on Vancouver Island, British Columbia, is used to assess preferential hillslope runoff contributions to peak flow generation. The model combines the matrix flow algorithm of the distributed hydrology soil vegetation model with a Green-Ampt formulation for calculating matrix and by-pass infiltration, preferential hillslope runoff initiation controlled by rainfall depth, and downslope subsurface flow rates prescribed based on at-site tracer tests. Model evaluation using 1972-1990 hydrometeorological data reveals that this formulation is successful in simulating subannual and larger peak flows. Model results suggest that preferential flow contributions to streamflow generation become greater than matrix flow contributions for unit area discharge values in excess of 2.8 mm/hr, corresponding to a peak flow return period of 2-3 months. This transition from matrix flow dominated runoff to preferential flow dominated runoff is consistent with an observed upper limit of groundwater response to precipitation for return periods in excess of 2 months. A break in slope in peak flow frequency curves at a return period of about 20 months appears to correspond to a change in storm characteristics. Thus at least three physically distinct populations of peak flows may exist at Carnation Creek. The ability of the model to simulate peak flows and groundwater responses for small and large storms suggests that it may be useful for addressing runoff process considerations in the debate whether forest management effects for annual and larger peak flows are similar to those inferred from analyses dominated by subannual peak flows.

  20. Disdrometer and Tipping Bucket Rain Gauge Handbook

    SciTech Connect

    Bartholomew. MJ

    2009-12-01

    The Distromet disdrometer model RD-80 and NovaLynx tipping bucket rain gauge model 260-2500E-12 are two devices deployed a few meters apart to measure the character and amount of liquid precipitation. The main purpose of the disdrometer is to measure drop size distribution, which it does over 20 size classes from 0.3 mm to 5.4 mm. The data from both instruments can be used to determine rain rate. The disdrometer results can also be used to infer several properties including drop number density, radar reflectivity, liquid water content, and energy flux. Two coefficients, N0 and Λ, from an exponential fit between drop diameter and drop number density, are routinely calculated. Data are collected once a minute. The instruments make completely different kinds of measurements. Rain that falls on the disdrometer sensor moves a plunger on a vertical axis. The disdrometer transforms the plunger motion into electrical impulses whose strength is proportional to drop diameter. The rain gauge is the conventional tipping bucket type. Each tip collects an amount equivalent to 0.01 in. of water, and each tip is counted by a data acquisition system anchored by a Campbell CR1000 data logger.

  1. Rain patterns motion over a region deduced from radar measurements

    NASA Astrophysics Data System (ADS)

    Pawlina, A.

    1986-04-01

    The knowledge of spatial and temporal evolution of precipitation patterns becomes important in the design of communication systems operating at the frequencies above 10 GHz (SHF) that have to counteract the attenuation by rain. One year of ground rain data obtained from weather radar measurements performed near Milan in Italy is analyzed to find out the preferential directions of motion of precipitation patterns over the observed region. The pattern motion is estimated by means of the cross-correlation procedure applied to 461 pairs of ground rain maps 18 minutes apart, originating from 88 separate rain events. The average velocity field of pattern displacement is found, showing an evident polarization towards east directions. The results may be seen as a contribution to the radio-climatological characterization of the region, aimed to improve rain-attenuation models required in the engineering of the SHF systems.

  2. Environmental fog/rain visual display system for aircraft simulators

    NASA Technical Reports Server (NTRS)

    Chase, W. D. (Inventor)

    1982-01-01

    An environmental fog/rain visual display system for aircraft simulators is described. The electronic elements of the system include a real time digital computer, a caligraphic color display which simulates landing lights of selective intensity, and a color television camera for producing a moving color display of the airport runway as depicted on a model terrain board. The mechanical simulation elements of the system include an environmental chamber which can produce natural fog, nonhomogeneous fog, rain and fog combined, or rain only. A pilot looking through the aircraft wind screen will look through the fog and/or rain generated in the environmental chamber onto a viewing screen with the simulated color image of the airport runway thereon, and observe a very real simulation of actual conditions of a runway as it would appear through actual fog and/or rain.

  3. Estimating the exceedance probability of rain rate by logistic regression

    NASA Technical Reports Server (NTRS)

    Chiu, Long S.; Kedem, Benjamin

    1990-01-01

    Recent studies have shown that the fraction of an area with rain intensity above a fixed threshold is highly correlated with the area-averaged rain rate. To estimate the fractional rainy area, a logistic regression model, which estimates the conditional probability that rain rate over an area exceeds a fixed threshold given the values of related covariates, is developed. The problem of dependency in the data in the estimation procedure is bypassed by the method of partial likelihood. Analyses of simulated scanning multichannel microwave radiometer and observed electrically scanning microwave radiometer data during the Global Atlantic Tropical Experiment period show that the use of logistic regression in pixel classification is superior to multiple regression in predicting whether rain rate at each pixel exceeds a given threshold, even in the presence of noisy data. The potential of the logistic regression technique in satellite rain rate estimation is discussed.

  4. Estimating 1 min rain rate distributions from numerical weather prediction

    NASA Astrophysics Data System (ADS)

    Paulson, Kevin S.

    2017-01-01

    Internationally recognized prognostic models of rain fade on terrestrial and Earth-space EHF links rely fundamentally on distributions of 1 min rain rates. Currently, in Rec. ITU-R P.837-6, these distributions are generated using the Salonen-Poiares Baptista method where 1 min rain rate distributions are estimated from long-term average annual accumulations provided by numerical weather prediction (NWP). This paper investigates an alternative to this method based on the distribution of 6 h accumulations available from the same NWPs. Rain rate fields covering the UK, produced by the Nimrod network of radars, are integrated to estimate the accumulations provided by NWP, and these are linked to distributions of fine-scale rain rates. The proposed method makes better use of the available data. It is verified on 15 NWP regions spanning the UK, and the extension to other regions is discussed.

  5. A Demonstration of Acid Rain

    ERIC Educational Resources Information Center

    Fong, Man Wai

    2004-01-01

    A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

  6. Acid Rain: What's the Forecast?

    ERIC Educational Resources Information Center

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  7. Acid Rain: An Educational Opportunity?

    ERIC Educational Resources Information Center

    Marion, James I.

    1984-01-01

    Deals with how educators can handle the subject of acid rain; illustrates suggestions with experiences of grade nine students visiting Frost Valley Environmental Education Center (Oliverea, New York) to learn scientific concepts through observation of outdoor phenomena, including a stream; and discusses acid rain, pH levels, and pollution control…

  8. Acid rain & electric utilities II

    SciTech Connect

    1997-12-31

    This document presents reports which were presented at the Acid Rain and Electric Utilities Conference. Topics include environmental issues and electric utilities; acid rain program overview; global climate change and carbon dioxide; emissions data management; compliance; emissions control; allowance and trading; nitrogen oxides; and assessment. Individual reports have been processed separately for the United States Department of Energy databases.

  9. Acid Rain: The Scientific Challenge.

    ERIC Educational Resources Information Center

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  10. An Umbrella for Acid Rain.

    ERIC Educational Resources Information Center

    Randal, Judith

    1979-01-01

    The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

  11. Rain Gardens: Stormwater Infiltrating Systems

    EPA Science Inventory

    The hydrological dynamics and changes in stormwater nutrient concentrations within rain gardens were studied by introducing captured stormwater runoff to rain gardens at EPA’s Urban Water Research Facility in Edison, New Jersey. The runoff used in these experiments was collected...

  12. Acid rain in Asia

    NASA Astrophysics Data System (ADS)

    Bhatti, Neeloo; Streets, David G.; Foell, Wesley K.

    1992-07-01

    Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

  13. Relation between cloud thickness-cloud number concentration differences and rain occurrence based on Koren-Feingold model

    NASA Astrophysics Data System (ADS)

    Sulistyowati, R.; Viridi, S.; Kurniadi, R.; Srigutomo, W.

    2016-11-01

    Koren-Feingold (KF) model, a model that relates growth of cloud thickness (H) and cloud number concentration (N) is discussed and analyzed in this work. Two boundary conditions are required by this model, where the first is cloud thickness potential H0 and the second is aerosol concentration N0 . The initial conditions are simply H(0) = 0 and N(0) = 0. Several pairs of (H0, N0) values are chosen in calculating the precipitation. Three categories of rainfall are used in this work, which are no drizzle D0, light drizzle D1, and drizzle D2. As H evolves in time t, it produces maximum cloud thickness Hmax and saturation cloud thickness Hsat , as also N does Nmax and Nsat . Two kinds of cloud thickness difference, ΔH1 = H0 - Hma x and ΔH2 = H0 - H sat are proposed and also for cloud concentration difference ΔN1 and ΔN2 with similar definitions. Pairs of (ΔH1 , ΔN1 ) and (ΔH2 , ΔN2 ) are used in analyzing simulation results. The first pair can be used as prediction of rainfall occurrence, while the second pair is more for confirmation and understanding the relation between cloud thickness and cloud concentration in producing rainfall. It is observed that H < H0 and N < N0 are always fulfilled. Rainfall in category D2 will have significant differences in H and N, while in category D0 will not. Typical differences for H are about 80% and 30-50% for both cases. Deeper discussion about (ΔH1 , ΔN1 ) and (ΔH2 , ΔN2 ) is presented in this work.

  14. Characteristics of rain penetration through a gravity ventilator used for natural ventilation.

    PubMed

    Kim, Taehyeung; Lee, Dong Ho; Ahn, Kwangseog; Ha, Hyunchul; Park, Heechang; Piao, Cheng Xu; Li, Xiaoyu; Seo, Jeoungyoon

    2008-01-01

    Gravity ventilators rely simply on air buoyancy to extract air and are widely used to exhaust air contaminants and heat from workplaces using minimal energy. They are designed to maximize the exhaust flow rate, but the rain penetration sometimes causes malfunctioning. In this study, the characteristics of rain penetration through a ventilator were examined as a preliminary study to develop a ventilator with the maximum exhaust capacity while minimizing rain penetration. A model ventilator was built and exposed to artificial rain and wind. The paths, intensities and amounts of penetration through the ventilator were observed and measured in qualitative and quantitative fashions. In the first phase, the pathways and intensities of rain penetration were visually observed. In the second phase, the amounts of rain penetration were quantitatively measured under the different configurations of ventilator components that were installed based on the information obtained in the first-phase experiment. The effects of wind speed, grill direction, rain drainage width, outer wall height, neck height and leaning angle of the outer wall from the vertical position were analyzed. Wind speed significantly affected rain penetration. Under the low crosswind conditions, the rain penetration intensities were under the limit of detection. Under the high crosswind conditions, grill direction and neck height were the most significant factors in reducing rain penetration. The installation of rain drainage was also important in reducing rain penetration. The experimental results suggest that, with proper configurations of its components, a gravity ventilator can be used for natural ventilation without significant rain penetration problems.

  15. Modeling rain-fed maize vulnerability to droughts using the standardized precipitation index from satellite estimated rainfall—Southern Malawi case study

    USGS Publications Warehouse

    Funk, Christopher C.; Verdin, James; Adams Chavula,; Gregory J. Husak,; Harikishan Jayanthi,; Tamuka Magadzire,

    2013-01-01

    During 1990s, disaster risk reduction emerged as a novel, proactive approach to managing risks from natural hazards. The World Bank, USAID, and other international donor agencies began making efforts to mainstream disaster risk reduction in countries whose population and economies were heavily dependent on rain-fed agriculture. This approach has more significance in light of the increasing climatic hazard patterns and the climate scenarios projected for different hazard prone countries in the world. The Famine Early Warning System Network (FEWS NET) has been monitoring the food security issues in the sub-Saharan Africa, Asia and in Haiti. FEWS NET monitors the rainfall and moisture availability conditions with the help of NOAA RFE2 data for deriving food security status in Africa. This paper highlights the efforts in using satellite estimated rainfall inputs to develop drought vulnerability models in the drought prone areas in Malawi. The satellite RFE2 based SPI corresponding to the critical tasseling and silking phases (in the months of January, February, and March) were statistically regressed with drought-induced yield losses at the district level. The analysis has shown that the drought conditions in February and early March lead to most damage to maize yields in this region. The district-wise vulnerabilities to drought were upscaled to obtain a regional maize vulnerability model for southern Malawi. The results would help in establishing an early monitoring mechanism for drought impact assessment, give the decision makers additional time to assess seasonal outcomes, and identify potential food-related hazards in Malawi.

  16. Spatial and Temporal Extrapolation of Disdrometer Size Distributions Based on a Lagrangian Trajectory Model of Falling Rain

    NASA Technical Reports Server (NTRS)

    Lane, John E.; Kasparis, Takis; Jones, W. Linwood; Metzger, Philip T.

    2009-01-01

    Methodologies to improve disdrometer processing, loosely based on mathematical techniques common to the field of particle flow and fluid mechanics, are examined and tested. The inclusion of advection and vertical wind field estimates appear to produce significantly improved results in a Lagrangian hydrometeor trajectory model, in spite of very strict assumptions of noninteracting hydrometeors, constant vertical air velocity, and time independent advection during the scan time interval. Wind field data can be extracted from each radar elevation scan by plotting and analyzing reflectivity contours over the disdrometer site and by collecting the radar radial velocity data to obtain estimates of advection. Specific regions of disdrometer spectra (drop size versus time) often exhibit strong gravitational sorting signatures, from which estimates of vertical velocity can be extracted. These independent wind field estimates become inputs and initial conditions to the Lagrangian trajectory simulation of falling hydrometeors.

  17. Rain attenuation measurements: Variability and data quality assessment

    NASA Technical Reports Server (NTRS)

    Crane, Robert K.

    1989-01-01

    Year to year variations in the cumulative distributions of rain rate or rain attenuation are evident in any of the published measurements for a single propagation path that span a period of several years of observation. These variations must be described by models for the prediction of rain attenuation statistics. Now that a large measurement data base has been assembled by the International Radio Consultative Committee, the information needed to assess variability is available. On the basis of 252 sample cumulative distribution functions for the occurrence of attenuation by rain, the expected year to year variation in attenuation at a fixed probability level in the 0.1 to 0.001 percent of a year range is estimated to be 27 percent. The expected deviation from an attenuation model prediction for a single year of observations is estimated to exceed 33 percent when any of the available global rain climate model are employed to estimate the rain rate statistics. The probability distribution for the variation in attenuation or rain rate at a fixed fraction of a year is lognormal. The lognormal behavior of the variate was used to compile the statistics for variability.

  18. Acidification and Acid Rain

    NASA Astrophysics Data System (ADS)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    endangers the existing biota. Concerns about acid (or acidic) rain in its modern sense were publicized by the Swedish soil scientist Svante Odén (1968). He argued, initially in the Swedish press, that long-term increases in the atmospheric deposition of acid could lower the pH of surface waters, cause a decline in fish stocks, deplete soils of nutrients, and accelerate damage to materials. By the 1970s, acidification of surface waters was reported in many countries in Europe as well as in North America. The late twentieth-century rush to understand the impact of acid rain was driven by: (i) reports of damaged or threatened freshwater fisheries and (ii) damaged forests. Perhaps the earliest linkage between acidic surface water and damage to fish was made by Dahl (1921) in southern Norway. There, spring runoff was sufficiently acidic to kill trout. It was not until the 1970s that a strong link was established between depressed pH, mobilization of aluminum from soil, and fish status ( Schofield and Trojnar,1980). The relationship between acidification of soils and forest health started with hypotheses in the 1960s and has slowly developed. Acid rain enhances the availability of some nutrients (e.g., nitrogen), and may either enhance or diminish the availability of others (e.g., calcium, magnesium, potassium, and phosphorus). Damage to anthropogenic structures, human health, and visibility have also raised concerns. The history of these early developments was summarized by Cowling (1982). Since the 1970s, sulfur and nitrogen emissions to the atmosphere have been reduced by 50-85% and 0-30%, respectively, both in North America and Europe. The emission reductions have occurred as a consequence of knowledge gained and economic factors. While recovery of water quality is underway in some areas, problems of acidification persist, and are now complicated by the effects of climate change ( Schindler, 1997).

  19. Seven Guideposts for Tropical Rain Forest Education.

    ERIC Educational Resources Information Center

    Rillero, Peter

    1999-01-01

    Identifies seven guideposts for tropical rain forest education. Aids teachers in finding structure and creating educational experiences that promote more complete understanding of tropical rain forests. (CCM)

  20. Quantification and modelling of water flow in rain-fed paddy fields in NE Thailand: Evidence of soil salinization under submerged conditions by artesian groundwater

    NASA Astrophysics Data System (ADS)

    Hammecker, Claude; Maeght, Jean-Luc; Grünberger, Olivier; Siltacho, Siwaporn; Srisruk, Kriengsak; Noble, Andrew

    2012-08-01

    SummaryWater flow and solute transport in soils forms an essential part in many groundwater hydrology studies. This is especially true for Northeast Thailand, where the agricultural land is affected by the soil salinity, which is a widespread and an increasing phenomenon affecting 25% of the agricultural land. Salinization appears as scattered discrete patches of 10-100 m2 in the lowlands, illustrated by white efflorescences during the dry season and bare soil during the cropping season. A field study was undertaken in farm plots to measure the water flow and solute transport within the soil surface and the vadose zone, both inside and outside a saline patch. The water flow was measured on the soil surface with lysimeters and infiltration rings, and was derived in the soil from the hydraulic gradients measured with tensiometers placed at different depths. The salt transport was evaluated with water traps also placed at different depths, where the soil water's electrical conductivity was measured throughout the rainy season. Field study results demonstrated that the accumulation of saline solutions in rain fed paddy fields, occurred mainly during the rainy season while the soil surface remained flooded. During this period the saline water table rose towards the soil surface independently of infiltration into the soil. It happened in specific places where the compacted soil layer, generally ubiquitous in the area at a depth of 40-50 cm, is interrupted. Therefore salinity appeareds in discret points as patches. Artesian upward flow already described in this area (Haworth et al., 1966; Williamson et al., 1989; Imaizumi et al., 2002) is most probably responsible for this water table rise, thereby affecting crop productivity. Numerical modelling of water flow using HYDRUS-3D further supported these results and showed that managing the depth of flooding within the plot can significantly reduce the outbreak of these saline plumes.

  1. Long-term observations of cloud condensation nuclei in the Amazon rain forest - Part 1: Aerosol size distribution, hygroscopicity, and new model parametrizations for CCN prediction

    NASA Astrophysics Data System (ADS)

    Pöhlker, Mira L.; Pöhlker, Christopher; Ditas, Florian; Klimach, Thomas; Hrabe de Angelis, Isabella; Araújo, Alessandro; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditz, Reiner; Gunthe, Sachin S.; Kesselmeier, Jürgen; Könemann, Tobias; Lavrič, Jošt V.; Martin, Scot T.; Mikhailov, Eugene; Moran-Zuloaga, Daniel; Rose, Diana; Saturno, Jorge; Su, Hang; Thalman, Ryan; Walter, David; Wang, Jian; Wolff, Stefan; Barbosa, Henrique M. J.; Artaxo, Paulo; Andreae, Meinrat O.; Pöschl, Ulrich

    2016-12-01

    Size-resolved long-term measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted at the remote Amazon Tall Tower Observatory (ATTO) in the central Amazon Basin over a 1-year period and full seasonal cycle (March 2014-February 2015). The measurements provide a climatology of CCN properties characteristic of a remote central Amazonian rain forest site.The CCN measurements were continuously cycled through 10 levels of supersaturation (S = 0.11 to 1.10 %) and span the aerosol particle size range from 20 to 245 nm. The mean critical diameters of CCN activation range from 43 nm at S = 1.10 % to 172 nm at S = 0.11 %. The particle hygroscopicity exhibits a pronounced size dependence with lower values for the Aitken mode (κAit = 0.14 ± 0.03), higher values for the accumulation mode (κAcc = 0.22 ± 0.05), and an overall mean value of κmean = 0.17 ± 0.06, consistent with high fractions of organic aerosol.The hygroscopicity parameter, κ, exhibits remarkably little temporal variability: no pronounced diurnal cycles, only weak seasonal trends, and few short-term variations during long-range transport events. In contrast, the CCN number concentrations exhibit a pronounced seasonal cycle, tracking the pollution-related seasonality in total aerosol concentration. We find that the variability in the CCN concentrations in the central Amazon is mostly driven by aerosol particle number concentration and size distribution, while variations in aerosol hygroscopicity and chemical composition matter only during a few episodes.For modeling purposes, we compare different approaches of predicting CCN number concentration and present a novel parametrization, which allows accurate CCN predictions based on a small set of input data.

  2. Rain waves-wind waves interaction application to scatterometry

    NASA Technical Reports Server (NTRS)

    Kharif, C.; Giovanangeli, J. P.; Bliven, L.

    1989-01-01

    Modulation of a rain wave pattern by longer waves has been studied. An analytical model taking into account capillarity effects and obliquity of short waves has been developed. Modulation rates in wave number and amplitude have been computed. Experiments were carried out in a wave tank. First results agree with theoretical models, but higher values of modulation rates are measured. These results could be taken into account for understanding the radar response from the sea surface during rain.

  3. Structural characteristics of rain fields

    NASA Astrophysics Data System (ADS)

    Mesnard, FréDéRic; Sauvageot, Henri

    2003-07-01

    This paper analyzes the shape of rain area size distributions (RASDs) observed by radar in tropical and midlatitude regions. The rain area is defined, with respect to a rain threshold τ, as the area, inside a contour, where the rain rate is higher than τ. The size considered is the diameter of the equivalent circular area D. The reflectivity peaks inside the rain areas are numbered and the rain areas put together by classes having the same peak number. The size distributions of the rain areas containing the same number of peaks p are well fitted by lognormal functions, the parameters of which, μp and σp, are weakly dependent on the conditions of the peak determination. The parameters μp and σp are found to be linked by a power relation. For D < 6 km most of the rain areas are single peaked. The RASD without peak number distinction is a lognormal mixture. Using the relations obtained for μp, σp, and the rain area number as functions of p enables one to simulate RASDs with results in good agreement with the observations. Because of the limitation in the radar sampling at both ends of the RASD and the decrease of area number with increasing size, the radar-observed RASDs are severely truncated. The possibility of an approximate fitting of the truncated RASD with diverse functions is discussed. At the intermediary values of the threshold, i.e., for τ ranging between 3 and 12 mm h-1, where the RASD is easiest to compute, the slope of these truncated distributions is not strongly dependent on the threshold. This slope appears not to be very sensitive to the minimum and maximum distances bounding the domain where the rain field is observed. The RASD is found to be sloping more over sea than over land. The slope of the RASDs shows a small diurnal variation but no significant annual variation. The "perimeter to area" (fractal) dimension of the rain area for the sample without peak number distinction is around 1.35. Single-peaked and multipeaked rain areas have

  4. Be an acid rain detective

    SciTech Connect

    Atwill, L.

    1982-07-01

    Acid rain is discussed in a question and answer format. The article is aimed at educating sport fishermen on the subject, and also to encourage them to write their congressmen, senators, and the President about the acid rain problem. The article also announces the availability of an acid rain test kit available through the magazine, ''Sports Afield.'' The kit consists of pH-test paper that turns different shades of pink and blue according to the pH of the water tested. The color of the test paper is then compared to a color chart furnished in the kit and an approximate pH can be determined.

  5. Can crops tolerate acid rain

    SciTech Connect

    Kaplan, J.K.

    1989-11-01

    This brief article describes work by scientists at the ARS Air Quality-Plant Growth and Development Laboratory in Raleigh, North Carolina, that indicates little damage to crops as a result of acid rain. In studies with simulated acid rain and 216 exposed varieties of 18 crops, there were no significant injuries nor was there reduced growth in most species. Results of chronic and acute exposures were correlated in sensitive tomato and soybean plants and in tolerant winter wheat and lettuce plants. These results suggest that 1-hour exposures could be used in the future to screen varieties for sensitivity to acid rain.

  6. Rain rate distributions for China from hourly rain gauge data

    NASA Astrophysics Data System (ADS)

    Li, Li; Zhu, Yuan-Jing; Zhao, Bolin

    1998-05-01

    Rain rate cumulative lognormal and Gamma distributions are calculated from hourly rain gauge data collected in 1991 at 333 locations in China. The Gamma distribution better represents the statistical rain rate distribution. So 1-min cumulative distribution to every gauge station is derived from the piecewise regression results of Gamma distribution through half-empirical conversion coefficients. We suggest the following actions: (1) In south China, there should be an approximately 9°E×5°N area of rain climatic zone K centered at about 112°E, 26°N inside International Telecommunication Union(ITU)-R designed zone M. (2) A geostationary communication satellite for China should be placed over eastern China (between 100°E and 125°E) in order to generally reduce the rain attenuation of Earth-satellite links all over China, based on rain rate distributions characteristic of China. Our data treatment procedure and results presented in this paper may be practical and useful in engineering design.

  7. Model State Acid Rain Rule

    EPA Pesticide Factsheets

    This document may be of assistance in applying the Title V air operating permit regulations. This document is part of the Title V Policy and Guidance Database available at www2.epa.gov/title-v-operating-permits/title-v-operating-permit-policy-and-guidance-document-index. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  8. Next generation paradigm for urban pluvial flood modelling, prediction, management and vulnerability reduction - Interaction between RainGain and Blue Green Dream projects

    NASA Astrophysics Data System (ADS)

    Maksimovic, C.

    2012-04-01

    The effects of climate change and increasing urbanisation call for a new paradigm for efficient planning, management and retrofitting of urban developments to increase resilience to climate change and to maximize ecosystem services. Improved management of urban floods from all sources in required. Time scale for well documented fluvial and coastal floods allows for timely response but surface (pluvial) flooding caused by intense local storms had not been given appropriate attention, Pitt Review (UK). Urban surface floods predictions require fine scale data and model resolutions. They have to be tackled locally by combining central inputs (meteorological services) with the efforts of the local entities. Although significant breakthrough in modelling of pluvial flooding was made there is a need to further enhance short term prediction of both rainfall and surface flooding. These issues are dealt with in the EU Iterreg project Rain Gain (RG). Breakthrough in urban flood mitigation can only be achieved by combined effects of advanced planning design, construction and management of urban water (blue) assets in interaction with urban vegetated areas' (green) assets. Changes in design and operation of blue and green assets, currently operating as two separate systems, is urgently required. Gaps in knowledge and technology will be introduced by EIT's Climate-KIC Blue Green Dream (BGD) project. The RG and BGD projects provide synergy of the "decoupled" blue and green systems to enhance multiple benefits to: urban amenity, flood management, heat island, biodiversity, resilience to drought thus energy requirements, thus increased quality of urban life at lower costs. Urban pluvial flood management will address two priority areas: Short Term rainfall Forecast and Short term flood surface forecast. Spatial resolution of short term rainfall forecast below 0.5 km2 and lead time of a few hours are needed. Improvements are achievable by combining data sources of raingauge networks

  9. Rain rate instrument for deployment at sea, phase 2

    NASA Technical Reports Server (NTRS)

    Steele, Jimmy W.

    1992-01-01

    This report describes, in detail, the SBIR Phase 2 contracting effort provided for by NASA Contract Number NAS8-38481 in which a prototype Rain Rate Sensor was developed. FWG Model RP101A is a fully functional rain rate and droplet size analyzing instrument. The RP101A is a fully functional rain rate and droplet size analyzing instrument. The RP101A consists of a fiber optic probe containing a 32-fiber array connected to an electronic signal processor. When interfaced to an IBM compatible personal computer and configured with appropriate software, the RP101A is capable of measuring rain rates and particles ranging in size from around 300 microns up to 6 to 7 millimeters. FWG Associates, Inc. intends to develop a production model from the prototype and continue the effort under NASA's SBIR Phase 3 program.

  10. Relating Convective and Stratiform Rain to Latent Heating

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Lang, Stephen; Zeng, Xiping; Shige, Shoichi; Takayabu, Yukari

    2010-01-01

    The relationship among surface rainfall, its intensity, and its associated stratiform amount is established by examining observed precipitation data from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). The results show that for moderate-high stratiform fractions, rain probabilities are strongly skewed toward light rain intensities. For convective-type rain, the peak probability of occurrence shifts to higher intensities but is still significantly skewed toward weaker rain rates. The main differences between the distributions for oceanic and continental rain are for heavily convective rain. The peak occurrence, as well as the tail of the distribution containing the extreme events, is shifted to higher intensities for continental rain. For rainy areas sampled at 0.58 horizontal resolution, the occurrence of conditional rain rates over 100 mm/day is significantly higher over land. Distributions of rain intensity versus stratiform fraction for simulated precipitation data obtained from cloud-resolving model (CRM) simulations are quite similar to those from the satellite, providing a basis for mapping simulated cloud quantities to the satellite observations. An improved convective-stratiform heating (CSH) algorithm is developed based on two sources of information: gridded rainfall quantities (i.e., the conditional intensity and the stratiform fraction) observed from the TRMM PR and synthetic cloud process data (i.e., latent heating, eddy heat flux convergence, and radiative heating/cooling) obtained from CRM simulations of convective cloud systems. The new CSH algorithm-derived heating has a noticeably different heating structure over both ocean and land regions compared to the previous CSH algorithm. Major differences between the new and old algorithms include a significant increase in the amount of low- and midlevel heating, a downward emphasis in the level of maximum cloud heating by about 1 km, and a larger variance between land and ocean in

  11. Runoff simulation using radar and rain gauge data

    NASA Astrophysics Data System (ADS)

    Liu, X. Y.; Mao, J. T.; Zhu, Y. J.; Li, J. R.

    2003-03-01

    The conceptual rainfall-runoff model TOPMODEL is used to simulate runoffs of the Meishan and Nianyushan catchments during the summers of 1998 and 1999 in the GAME/HUBEX (GEWEX Asia Monsoon Experiment /HUAIHE River Basin Experiment) project. The rainfall distributions are estimated by weather radar and rain gauge networks according to different methods. Observed and simulated runoffs are compared and analyzed for both catchments. Results show that (1) the runoff of the catchment is best simulated by radar data combined with rain gauge network data from inside the catchment, and (2) the rainfall estimated by radar adjusted by a few rain gauges outside the catchment can be used to simulate runoff equally as well as using the dense rain gauge network alone.

  12. Low-Latitude Ethane Rain on Titan

    NASA Technical Reports Server (NTRS)

    Dalba, Paul A.; Buratti, Bonnie J.; Brown, R. H.; Barnes, J. W.; Baines, K. H.; Sotin, C.; Clark, R. N.; Lawrence, K. J.; Nicholson, P. D.

    2012-01-01

    Cassini ISS observed multiple widespread changes in surface brightness in Titan's equatorial regions over the past three years. These brightness variations are attributed to rainfall from cloud systems that appear to form seasonally. Determining the composition of this rainfall is an important step in understanding the "methanological" cycle on Titan. I use data from Cassini VIMS to complete a spectroscopic investigation of multiple rain-wetted areas. I compute "before-and-after" spectral ratios of any areas that show either deposition or evaporation of rain. By comparing these spectral ratios to a model of liquid ethane, I find that the rain is most likely composed of liquid ethane. The spectrum of liquid ethane contains multiple absorption features that fall within the 2-micron and 5-micron spectral windows in Titan's atmosphere. I show that these features are visible in the spectra taken of Titan's surface and that they are characteristically different than those in the spectrum of liquid methane. Furthermore, just as ISS saw the surface brightness reverting to its original state after a period of time, I show that VIMS observations of later flybys show the surface composition in different stages of returning to its initial form.

  13. Atmospheric dust and acid rain

    SciTech Connect

    Hedin, L.O.; Likens, G.E.

    1996-12-01

    Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

  14. MAP3S/RAINE modeling abstracts, 1980. [Concise descriptions of models and availability for calculation of airborne concentration of sulfur dioxide and sulfate

    SciTech Connect

    Michael, P.

    1980-07-01

    The MultiState Atmospheric Power Production Pollution Study (MAP3S) has produced as a primary research output a number of numerical models for the calculation of airborne concentrations of sulfur dioxide and sulfate resulting from anthropogenic sources. Concise descriptions of these models, and of related modeling developments, are collected in this report. For each model, or model component, there is included a listing of the authors, a summary of what it is the model calculates and the method used, a list of references, and a statement of availability.

  15. The regional costs and benefits of acid rain control

    SciTech Connect

    Berkman, M.P.

    1991-01-01

    Congress recently enacted acid rain control legislation as part of the 1990 Clean Air Act Amendments following a decade-long debate among disparate regional interests. Although Congress succeeded in drafting a law acceptable to all regions, the regional costs and benefits of the legislation remain uncertain. The research presented here attempts to estimate the regional costs and benefits and the economic impacts of acid rain controls. These estimates are made using a modeling system composed of econometric, linear programming and input-output models. The econometric and linear programming components describe markets for electricity and coal. The outputs of these components including capital investment, electricity demand, and coal production are taken as exogenous inputs by a multiregional input-output model. The input-output model produces estimates of changes in final demand, gross output, and employment. The utility linear programming model also predicts sulfur dioxide emissions (an acid-rain precursor). According to model simulations, the costs of acid rain control exceed the benefits for many regions including several regions customarily thought to be the major beneficiaries of acid rain control such as New England.

  16. Sensitivity of hydrometeor profiles and satellite brightness temperatures to model microphysics for MCSs over land and ocean: Model comparison using EOF analysis and implications for rain and latent heat retrievals

    NASA Astrophysics Data System (ADS)

    Seo, Eun-Kyoung

    The impact of model microphysics on the relationships between microphysical variables and derived satellite microwave brightness temperatures (T B's) and on the retrievals of microphysical variables was using a three-dimensional, nonhydrostatic, adaptive-grid cloud model to simulate two mesoscale convective systems, one over land and one over ocean. Four microphysical schemes (each employing 3-ice bulk parameterizations) were compared in both convective and stratiform precipitation using Empirical Orthogonal Function analysis. The validity of the microphysical schemes suggests that over land the model microphysical schemes produce too much reflectivity aloft and too rapid a decrease in reflectivity from the melting level to the surface, and over ocean the simulations produced more graupel and not enough rain. Model microphysics had a noticeable impact on the relations between the hydrometeor structure and TB's. Classified in terms of TB 's, the microphysical schemes produce significantly different mean vertical profiles of cloud water, cloud ice, snow, vertical velocity, and latent heating, especially in stratiform clouds. Vertical velocity and latent heating in simulated stratiform clouds were not well correlated with TB's for any of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) frequencies. Differences in the amount of supercooled cloud water produced in the various schemes accounted for much of the variation in TB relations. The uncertainty in retrieving hydrometeor and latent heating profiles for passive microwave measurements has been examined quantitatively. The four microphysical schemes exhibited analogous uncertainties in retrieving rain and graupel, but very different uncertainties in retrieving cloud water, cloud ice, and snow. The uncertainty in retrieving latent heating appears to be related to the insensitivity of TMI frequencies to cloud water, cloud ice, and snow. Structural differences in hydrometeor and latent heating

  17. On validation of the rain climatic zone designations for Nigeria

    NASA Astrophysics Data System (ADS)

    Obiyemi, O. O.; Ibiyemi, T. S.; Ojo, J. S.

    2016-04-01

    In this paper, validation of rain climatic zone classifications for Nigeria is presented based on global radio-climatic models by the International Telecommunication Union-Radiocommunication (ITU-R) and Crane. Rain rate estimates deduced from several ground-based measurements and those earlier estimated from the precipitation index on the Tropical Rain Measurement Mission (TRMM) were employed for the validation exercise. Although earlier classifications indicated that Nigeria falls into zones P, Q, N, and K for the ITU-R designations, and zones E and H for Crane's climatic zone designations, the results however confirmed that the rain climatic zones across Nigeria can only be classified into four, namely P, Q, M, and N for the ITU-R designations, while the designations by Crane exhibited only three zones, namely E, G, and H. The ITU-R classification was found to be more suitable for planning microwave and millimeter wave links across Nigeria. The research outcomes are vital in boosting the confidence level of system designers in using the ITU-R designations as presented in the map developed for the rain zone designations for estimating the attenuation induced by rain along satellite and terrestrial microwave links over Nigeria.

  18. Vegetable production after heavy rains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is not clear if extraordinary precipitation stored in the soil was able to support vegetable crops planted after rains events returned to normal levels. Cucumber and sweet corn were established from seed and non-pungent jalapeno peppers were established from 8-week old transplants on beds. Half...

  19. THE ACID RAIN NOX PROGRAM

    EPA Science Inventory

    Between 350,000 and 400,000 tons of annual NOx emissions have been eliminated as a result of Phase I of the Acid Rain NOx Program. As expected. the utilities have chosen emissions averaging as the primary compliance option. This reflects that, in general, NO x reductions have ...

  20. On-Disk Coronal Rain

    NASA Astrophysics Data System (ADS)

    Antolin, Patrick; Vissers, Gregal; Rouppe van der Voort, Luc

    2012-10-01

    Small and elongated, cool and dense blob-like structures are being reported with high resolution telescopes in physically different regions throughout the solar atmosphere. Their detection and the understanding of their formation, morphology, and thermodynamical characteristics can provide important information on their hosting environment, especially concerning the magnetic field, whose understanding constitutes a major problem in solar physics. An example of such blobs is coronal rain, a phenomenon of thermal non-equilibrium observed in active region loops, which consists of cool and dense chromospheric blobs falling along loop-like paths from coronal heights. So far, only off-limb coronal rain has been observed, and few reports on the phenomenon exist. In the present work, several data sets of on-disk Hα observations with the CRisp Imaging SpectroPolarimeter (CRISP) at the Swedish 1- m Solar Telescope (SST) are analyzed. A special family of on-disk blobs is selected for each data set, and a statistical analysis is carried out on their dynamics, morphology, and temperature. All characteristics present distributions which are very similar to reported coronal rain statistics. We discuss possible interpretations considering other similar blob-like structures reported so far and show that a coronal rain interpretation is the most likely one. The chromospheric nature of the blobs and the projection effects (which eliminate all direct possibilities of height estimation) on one side, and their small sizes, fast dynamics, and especially their faint character (offering low contrast with the background intensity) on the other side, are found as the main causes for the absence until now of the detection of this on-disk coronal rain counterpart.

  1. Rain Hampers Tsunami Relief Efforts

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The cleanup and relief efforts from the recent tsunamis continue in coastal communities that were ravaged by the waves all across the Indian Ocean. Heavy rains have further complicated the matter and added to the misery in parts of eastern Sri Lanka. Between December 28, 2004, and January 5, 2005, up to 10 to 15 inches of rain may have fallen along the southeast coast of the island, and as much as 20 inches (red areas) fell just offshore. This rainfall map was created by the TRMM-based, near-real time Multi-satellite Precipitation Analysis (MPA) at the NASA Goddard Space Flight Center, which monitors rainfall over the global tropics. The map shows that many other regions around the Indian Ocean were also affected by the rains, including Malaysia and parts of Sumatra. The heaviest rains fell on December 31 and January 4. The rains were likely the result of a combination of the northeast monsoon interacting with the topography and an active phase of what is known as the Madden-Julian Oscillation (MJO) (or 30-60 day oscillation). The MJO is a large-scale disturbance that propagates eastward from the Indian Ocean into the West Pacific Ocean, bringing extended periods of unsettled weather with it. Individual convective complexes within the MJO can last on the order of a day. TRMM is a joint mission between NASA and the Japanese space agency JAXA. NASA image produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).

  2. Nature in the Classroom: Acid Rain.

    ERIC Educational Resources Information Center

    Doyle, Charles

    1982-01-01

    As a lesson topic, acid rain is defined, its chemistry given, and its development since the 1950s described. The worldwide effects of acid rain are discussed along with the available technology for controlling the problem. (CM)

  3. Acid Rain: The Silent Environmental Threat.

    ERIC Educational Resources Information Center

    Zmud, Mia

    1992-01-01

    Describes the silent environmental threat posed by acid rain. Caused mainly by manmade pollutants, acid rain damages water and trees, decreases visibility, corrodes monuments, and threatens public health. The article includes guidelines for action. (SM)

  4. Acid Rain Program Opt-in Factsheet

    EPA Pesticide Factsheets

    Learn about the Opt-in Program, which allows sources not required to participate in the Acid Rain Program the opportunity to enter the program on a voluntary basis and receive Acid Rain Program allowances.

  5. Characterization of tropical precipitation using drop size distribution and rain rate-radar reflectivity relation

    NASA Astrophysics Data System (ADS)

    Das, Saurabh; Maitra, Animesh

    2017-03-01

    Characterization of precipitation is important for proper interpretation of rain information from remotely sensed data. Rain attenuation and radar reflectivity (Z) depend directly on the drop size distribution (DSD). The relation between radar reflectivity/rain attenuation and rain rate (R) varies widely depending upon the origin, topography, and drop evolution mechanism and needs further understanding of the precipitation characteristics. The present work utilizes 2 years of concurrent measurements of DSD using a ground-based disdrometer at five diverse climatic conditions in Indian subcontinent and explores the possibility of rain classification based on microphysical characteristics of precipitation. It is observed that both gamma and lognormal distributions are performing almost similar for Indian region with a marginally better performance by one model than other depending upon the locations. It has also been found that shape-slope relationship of gamma distribution can be a good indicator of rain type. The Z-R relation, Z = ARb, is found to vary widely for different precipitation systems, with convective rain that has higher values of A than the stratiform rain for two locations, whereas the reverse is observed for the rest of the three locations. Further, the results indicate that the majority of rainfall (>50%) in Indian region is due to the convective rain although the occurrence time of convective rain is low (<10%).

  6. Acid Rain: What We Must Do.

    ERIC Educational Resources Information Center

    Gorham, Eville

    1983-01-01

    Addresses questions about the nature, source, and history of acid rain. In addition, discusses the questions: Why is acid rain a problem? Is acid rain getting worse? What is the threat of further problems? Concludes that it is time to act on the problem and recommends an appropriate course of action. (JN)

  7. Create a Rain Forest in the Gym.

    ERIC Educational Resources Information Center

    Kane, Karen

    1995-01-01

    Describes a creative interdisciplinary program for K-3 students that involves setting up a rain forest in the gymnasium to teach students gymnastic skills in the context of the Amazon rain forest. The paper describes how to set up the rain forest and teach a variety of classes. Rainforest resources are included. (SM)

  8. Rain, Snow, and Spring Runoff Revisited.

    ERIC Educational Resources Information Center

    Bohren, Craig F.

    1995-01-01

    Explores the theory behind the correlation between warm rain, rapid snowmelt, and the subsequent runoff using the concepts of enthalpy, thermal transfer, and energy transfer. Concludes that rapid runoff is not a consequence of rain per se but of the high humidities associated with the rain. (JRH)

  9. A Walk in the Rain Forest.

    ERIC Educational Resources Information Center

    Gustafson, Glenn

    2001-01-01

    Presents a learning project in which students prepare a guided, multisensory rain forest tour representing its ecology. Develops five stop points presenting a theme or an important aspect of the rain forest. Includes a list of selected resources for rain forest studies. (YDS)

  10. A recent and abrupt decline in the East African long rains

    NASA Astrophysics Data System (ADS)

    Lyon, Bradfield; DeWitt, David G.

    2012-01-01

    The successive failure of the East African short rains (typically October-December) and subsequent long rains (March-May) in 2010-11 plunged much of the region into severe drought, impacting millions of people and triggering a humanitarian crisis. While poor short rains in 2010 were generally anticipated given linkages with La Niña, the subsequent long rains do not exhibit similar predictability. Here we show the long rains failure in boreal spring of 2011 is consistent with a recurrent large-scale precipitation pattern that followed their abrupt decline around 1999. Using observations and climate model simulations, we show the abrupt decline in long rains precipitation is linked to similarly abrupt changes in sea surface temperatures, predominately in the tropical Pacific basin.

  11. Acid rain attack on outdoor sculpture in perspective

    NASA Astrophysics Data System (ADS)

    Livingston, Richard A.

    2016-12-01

    A major concern motivating research in acid rain materials effects has been the potential for damage to cultural heritage, particularly outdoor marble and bronze sculpture. However, a combination of field and laboratory studies has failed to show a correlation between rain pH and loss of materials. In order to understand this counterintuitive lack of acid rain effect, an aqueous geochemical modeling approach was used to analyze rain runoff chemistry for the relative importance of acid rain neutralization, dry deposition, and in the case of marble, natural carbonate dissolution. This approach involved the development of pH - SO42- phase diagrams for marble (calcium carbonate) and bronze (copper) under ambient environmental conditions. This then enabled reaction path modeling of the acid neutralization process using the pH range typically found in wet deposition (3.5-6). The results were for marble that the theoretical maximum amount of Ca2+ ion that could be lost due acid rain neutralization would be 0.158 mmol/l compared to 10.5 mmol/l by dry deposition, and for bronze, the Cu2+ ion losses would be 0.21 mmol/l and 47.3 mmol/l respectively. Consequently dry deposition effects on these materials have the potential to dominate over wet deposition effects. To test these predictions the geochemical models were applied to examples of data sets from mass balance (runoff vs rainfall) studies on a marble statue in New York City and some bronze memorial plaques at Gettysburg PA. Although these data sets were collected in the early 1980s they remain valid for demonstrating the mass balance method. For the marble statue, the mean Ca2+ losses by dry deposition was about 69% of the total compared 0.3% for acid rain neutralization, which was less than the natural carbonate dissolution losses of 0.8%. For the bronze, the mean Cu2+ losses were 70.6% by SO42- dry deposition and 23% by NO3- dry deposition compared to 6.4% by acid rain neutralization. Thus for both cases the wet

  12. Dispersal of Salmonella Typhimurium by rain splash onto tomato plants.

    PubMed

    Cevallos-Cevallos, Juan M; Danyluk, Michelle D; Gu, Ganyu; Vallad, Gary E; van Bruggen, Ariena H C

    2012-03-01

    Outbreaks of Salmonella enterica have increasingly been associated with tomatoes and traced back to production areas, but the spread of Salmonella from a point source onto plants has not been described. Splash dispersal by rain could be one means of dissemination. Green fluorescent protein-labeled, kanamycin-resistant Salmonella enterica sv. Typhimurium dispensed on the surface of plastic mulch, organic mulch, or soil at 10⁸ CFU/cm² was used as the point source in the center of a rain simulator. Tomato plants in soil with and without plastic or organic mulch were placed around the point source, and rain intensities of 60 and 110 mm/h were applied for 5, 10, 20, and 30 min. Dispersal of Salmonella followed a negative exponential model with a half distance of 3 cm at 110 mm/h. Dispersed Salmonella survived for 3 days on tomato leaflets, with a total decline of 5 log and an initial decimal reduction time of 10 h. Recovery of dispersed Salmonella from plants at the maximum observed distance ranged from 3 CFU/g of leaflet after a rain episode of 110 mm/h for 10 min on soil to 117 CFU/g of leaflet on plastic mulch. Dispersal of Salmonella on plants with and without mulch was significantly enhanced by increasing rain duration from 0 to 10 min, but dispersal was reduced when rainfall duration increased from 10 to 30 min. Salmonella may be dispersed by rain to contaminate tomato plants in the field, especially during rain events of 10 min and when plastic mulch is used.

  13. Rain fade in Ku-band VSAT networks - A design consideration

    NASA Astrophysics Data System (ADS)

    Raust, Eric H.

    The components of a Very Small Aperture Terminal (VSAT) network are shown to determine the effect that rainfall has on Ku-band satellite communications. This paper considers the effect of the signal attenuation caused by rain as predicted by a well known rain fade model. The result, of considering the highest rain attenuations experienced is related to both transmission availabilities and signal margins. The results of link calculations are tabulated for typical network designs. These results show that proper selection of the VSAT's components and the satellite transponder power can all but eliminate rain outages while maintaining the economics of a Ku-band VSAT network.

  14. The rain-powered cart

    NASA Astrophysics Data System (ADS)

    Mungan, Carl E.; Lipscombe, Trevor C.

    2016-09-01

    A frictionless cart in the shape of a right triangle (with the vertical side forward) is elastically impacted by vertically falling raindrops. The speed of the cart as a function of time can be analytically deduced as an exercise in the use of trigonometric and hyperbolic functions. A characteristic time defines the approach to a terminal speed which is a sizeable fraction of the speed of the rain. The treatment is accessible to a student in a calculus-based mechanics course.

  15. Low-Latitude Ethane Rain on Titan

    NASA Astrophysics Data System (ADS)

    Dalba, Paul; Buratti, B. J.; Brown, R. H.; Barnes, J. W.; Baines, K. H.; Sotin, C.; Clark, R. N.; Lawrence, K. J.; Nicholson, P. D.

    2012-10-01

    Cassini ISS observed multiple widespread changes in surface brightness in Titan's equatorial regions over the past three years (Barnes, J. W. et al. 2012, Icarus, submitted). These brightness variations are attributed to rainfall from cloud systems that appear to form seasonally (Turtle, E. P. et al. 2011, Science, 331, 1414-1417). Determining the composition of this rainfall is an important step in understanding the “methanological” cycle that dominates Titan's surface and atmosphere. In this study, we use data from Cassini VIMS to complete a thorough spectroscopic investigation of rain-wetted areas near Yalaing Terra, Hetpet Regio and central Adiri on Titan. We compute “before-and-after” spectral ratios of any areas that show either deposition or evaporation of rain at any point in the time span of August 2009 to January 2012. By comparing these spectral ratios to a model of liquid ethane that was calculated to match the resolution and sampling interval of VIMS (Brown, R. H. et al. 2008, Nature, 454, 607-610), we find that the rain is most likely composed of liquid ethane. The spectrum of liquid ethane contains multiple absorption features that fortunately fall within the 2-micron and 5-micron spectral windows in Titan's atmosphere. We show that these features are visible in the spectra taken of Titan's surface and that they are characteristically different than those in the spectrum of liquid methane. Furthermore, just as ISS saw the surface brightness reverting to its original state after a period of time, we show that VIMS observations of later flybys show the surface composition in different stages of returning to its initial form as well. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract to the National Aeronautics and Space Administration. Copyright 2012. All rights reserved.

  16. Low-latitude ethane rain on Titan

    NASA Astrophysics Data System (ADS)

    Dalba, P. A.; Buratti, B. J.; Brown, R. H.; Barnes, J. W.; Baines, K. H.; Sotin, C.; Clark, R. N.; Lawrence, K. J.; Nicholson, P. D.

    2012-12-01

    Cassini ISS observed multiple widespread changes in surface brightness in Titan's equatorial regions over the past three years (Barnes, J. W. et al. 2012, Icarus, submitted). These brightness variations are attributed to rainfall from cloud systems that appear to form seasonally (Turtle, E. P. et al. 2011, Science, 331, 1414-1417). Determining the composition of this rainfall is an important step in understanding the "methanological" cycle that dominates Titan's surface and atmosphere. In this study, we use data from Cassini VIMS to complete a thorough spectroscopic investigation of rain-wetted areas near Yalaing Terra, Hetpet Regio and central Adiri on Titan. We compute "before-and-after" spectral ratios of any areas that show either deposition or evaporation of rain at any point in the time span of August 2009 to January 2012. By comparing these spectral ratios to a model of liquid ethane that was calculated to match the resolution and sampling interval of VIMS (Brown, R. H. et al. 2008, Nature, 454, 607-610), we find that the rain is most likely composed of liquid ethane. The spectrum of liquid ethane contains multiple absorption features that fortunately fall within the 2-micron and 5-micron spectral windows in Titan's atmosphere. We show that these features are visible in the spectra taken of Titan's surface and that they are characteristically different than those in the spectrum of liquid methane. Furthermore, just as ISS saw the surface brightness reverting to its original state after a period of time, we show that VIMS observations of later flybys show the surface composition in different stages of returning to its initial form as well. Funded by NASA.

  17. Acid Rain: What It Is -- How You Can Help!

    ERIC Educational Resources Information Center

    National Wildlife Federation, Washington, DC.

    This publication discusses the nature and consequences of acid precipitation (commonly called acid rain). Topic areas include: (1) the chemical nature of acid rain; (2) sources of acid rain; (3) geographic areas where acid rain is a problem; (4) effects of acid rain on lakes; (5) effect of acid rain on vegetation; (6) possible effects of acid rain…

  18. Observing the Formation of Flare-driven Coronal Rain

    NASA Astrophysics Data System (ADS)

    Scullion, E.; Rouppe van der Voort, L.; Antolin, P.; Wedemeyer, S.; Vissers, G.; Kontar, E. P.; Gallagher, P. T.

    2016-12-01

    Flare-driven coronal rain can manifest from rapidly cooled plasma condensations near coronal loop tops in thermally unstable postflare arcades. We detect five phases that characterize the postflare decay: heating, evaporation, conductive cooling dominance for ˜120 s, radiative/enthalpy cooling dominance for ˜4700 s, and finally catastrophic cooling occurring within 35-124 s, leading to rain strands with a periodicity of 55-70 s. We find an excellent agreement between the observations and model predictions of the dominant cooling timescales and the onset of catastrophic cooling. At the rain-formation site, we detect comoving, multithermal rain clumps that undergo catastrophic cooling from ˜1 MK to ˜22,000 K. During catastrophic cooling, the plasma cools at a maximum rate of 22,700 K s-1 in multiple loop-top sources. We calculated the density of the extreme-ultraviolet (EUV) plasma from the differential emission measure of the multithermal source employing regularized inversion. Assuming a pressure balance, we estimate the density of the chromospheric component of rain to be 9.21 × 1011 ± 1.76 × 1011 cm-3, which is comparable with quiescent coronal rain densities. With up to eight parallel strands in the EUV loop cross section, we calculate the mass loss rate from the postflare arcade to be as much as 1.98 × 1012 ± 4.95 × 1011 g s-1. Finally, we reveal a close proximity between the model predictions of {10}5.8 K and the observed properties between {10}5.9 and {10}6.2 K, which defines the temperature onset of catastrophic cooling. The close correspondence between the observations and numerical models suggests that indeed acoustic waves (with a sound travel time of 68 s) could play an important role in redistributing energy and sustaining the enthalpy-based radiative cooling.

  19. Dust Rains Deliver Diverse Assemblages of Microorganisms to the Eastern Mediterranean

    PubMed Central

    Itani, Ghida Nouhad; Smith, Colin Andrew

    2016-01-01

    Dust rains may be particularly effective at delivering microorganisms, yet their biodiversities have been seldom examined. During 2011 and 2012 in Beirut, Lebanon, 16 of 21 collected rainfalls appeared dusty. Trajectory modelling of air mass origins was consistent with North African sources and at least one Southwest Asian source. As much as ~4 g particulate matter, ~20 μg DNA, and 50 million colony forming units were found deposited per square meter during rainfalls each lasting less than one day. Sequencing of 93 bacteria and 25 fungi cultured from rain samples revealed diverse bacterial phyla, both Gram positive and negative, and Ascomycota fungi. Denaturing Gradient Gel Electrophoresis of amplified 16S rDNA of 13 rains revealed distinct and diverse assemblages of bacteria. Dust rain 16S libraries yielded 131 sequences matching, in decreasing order of abundance, Betaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Clean rain 16S libraries yielded 33 sequences matching only Betaproteobacteria family Oxalobacteraceae. Microbial composition varied between dust rains, and more diverse and different microbes were found in dust rains than clean rains. These results show that dust rains deliver diverse communities of microorganisms that may be complex products of revived desert soil species and fertilized cloud species. PMID:26939571

  20. Dust Rains Deliver Diverse Assemblages of Microorganisms to the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Itani, Ghida Nouhad; Smith, Colin Andrew

    2016-03-01

    Dust rains may be particularly effective at delivering microorganisms, yet their biodiversities have been seldom examined. During 2011 and 2012 in Beirut, Lebanon, 16 of 21 collected rainfalls appeared dusty. Trajectory modelling of air mass origins was consistent with North African sources and at least one Southwest Asian source. As much as ~4 g particulate matter, ~20 μg DNA, and 50 million colony forming units were found deposited per square meter during rainfalls each lasting less than one day. Sequencing of 93 bacteria and 25 fungi cultured from rain samples revealed diverse bacterial phyla, both Gram positive and negative, and Ascomycota fungi. Denaturing Gradient Gel Electrophoresis of amplified 16S rDNA of 13 rains revealed distinct and diverse assemblages of bacteria. Dust rain 16S libraries yielded 131 sequences matching, in decreasing order of abundance, Betaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Clean rain 16S libraries yielded 33 sequences matching only Betaproteobacteria family Oxalobacteraceae. Microbial composition varied between dust rains, and more diverse and different microbes were found in dust rains than clean rains. These results show that dust rains deliver diverse communities of microorganisms that may be complex products of revived desert soil species and fertilized cloud species.

  1. Nonlinear response in runoff magnitude to fluctuating rain patterns.

    PubMed

    Curtu, R; Fonley, M

    2015-03-01

    The runoff coefficient of a hillslope is a reliable measure for changes in the streamflow response at the river link outlet. A high runoff coefficient is a good indicator of the possibility of flash floods. Although the relationship between runoff coefficient and streamflow has been the subject of much study, the physical mechanisms affecting runoff coefficient including the dependence on precipitation pattern remain open topics for investigation. In this paper, we analyze a rainfall-runoff model at the hillslope scale as that hillslope is forced with different rain patterns: constant rain and fluctuating rain with different frequencies and amplitudes. When an oscillatory precipitation pattern is applied, although the same amount of water may enter the system, its response (measured by the runoff coefficient) will be maximum for a certain frequency of precipitation. The significant increase in runoff coefficient after a certain pattern of rainfall can be a potential explanation for the conditions preceding flash-floods.

  2. Raindrop and flow interactions for interrill erosion with wind-driven rain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind-driven rain (WDR) experiments were conducted to evaluate interrill component of the Water Erosion Prediction Project (WEPP) model with two-dimensional experimental set-up in wind tunnel. Synchronized wind and rain simulations were applied to soil surfaces on windward and leeward slopes of 7, 15...

  3. Comparison of Instantaneous Frequency Scaling from Rain Attenuation and Optical Disdrometer Measurements at K/Q bands

    NASA Technical Reports Server (NTRS)

    Nessel, James; Zemba, Michael; Luini, Lorenzo; Riva, Carlo

    2015-01-01

    Rain attenuation is strongly dependent on the rain rate, but also on the rain drop size distribution (DSD). Typically, models utilize an average drop size distribution, such as those developed by Laws and Parsons, or Marshall and Palmer. However, individual rain events may possess drop size distributions which could be significantly different from the average and will impact, for example, fade mitigation techniques which utilize channel performance estimates from a signal at a different frequency. Therefore, a good understanding of the characteristics and variability of the raindrop size distribution is extremely important in predicting rain attenuation and instantaneous frequency scaling parameters on an event-toevent basis. Since June 2014, NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have measured the attenuation due to rain in Milan, Italy, on the 20/40 GHz beacon signal broadcast from the Alphasat TDP#5 Aldo Paraboni Q/V-band Payload. Concomitant with these measurements are the measurements of drop size distribution and rain rate utilizing a Thies Clima laser precipitation monitor (disdrometer). In this paper, we discuss the comparison of the predicted rain attenuation at 20 and 40 GHz derived from the drop size distribution data with the measured rain attenuation. The results are compared on statistical and real-time bases. We will investigate the performance of the rain attenuation model, instantaneous frequency scaling, and the distribution of the scaling factor. Further, seasonal rain characteristics will be analysed.

  4. A numerical study of the acid rain in northern Taiwan in winter season

    SciTech Connect

    Chen, Ching-Sen; Deng, Zen-Sing

    1996-12-31

    Two-thirds of the land mass of Taiwan island is covered by mountains. In winter precipitation could occur in northern Taiwan when the prevailing wind was from northeastern direction. In northern Taiwan the acid rain (pH value less than 5.0) in winter time could contribute about 30 rain in the whole year. A three-dimensional numerical model with terrain following coordinated system was used to simulate the precipitation system and the characteristics of acid rain. A smooth terrain was assumed in the model. A mean sounding was used to initialize the numerical model when acid rain occurred in northern Taiwan during winter time from 1991 to 1993. Investigations of the effect of pollutions from abroad on the acid rain in northern Taiwan in winter are considered for the future.

  5. Study of rain attenuation in Ka band for satellite communication in South Korea

    NASA Astrophysics Data System (ADS)

    Shrestha, Sujan; Choi, Dong-You

    2016-10-01

    The important factor to be considered in the link budget estimation for satellite communication systems, operating at frequencies above 10 GHz is the rain attenuation. Scattering and absorption are the main concern for system designers at these frequency bands. This has resulted in the need for suitable prediction models that can best provide estimates of attenuation due to rain with available information of rain attenuation data. Researchers have developed models that can be used to estimate 1-min rainfall attenuation distribution for earth space link but there is still some confusion with regard to choosing the right model to predict attenuation for the location of interest. In this context, the existing prediction models need to be tested against the measured results. This paper presents studies on rain attenuation at 19.8 GHz, which specifies the performance parameters for Ka-Band under earth space communication system. It presents the experimental result of rain rates and rain-induced attenuation in 19.8 and 20.73 GHz for vertical and circular polarization respectively. The received signal data for rain attenuation and rain rate were collected at 10 s intervals over a three year periods from 2013 to 2015. The data highlights the impact of clear air variation and rain fade loss. Rain rate data was measured through OTT Parsivel. During the observation period, rain rates of about 50 mm/h and attenuation values of 11.6 dB for 0.01% of the time were noted. The experimental link was set up at Korea Radio Promotion Association, Mokdong, Seoul. Out of several models, this paper present discussion and comparison of ITU-R P.618-12, Unified Method, Dissanayake Allnutt and Haidara (DAH), Simple Attenuation (SAM), Crane Global and Ramachandran and Kumar models. The relative error margin of 27.51, 89.84,72.46% and 67.24, 130.84, 166.48% are obtained for 0.1%, 0.01% and 0.001% of the time for 19.8 and 20.73 GHz under vertical and circular polarization respectively from ITU

  6. Rain on small tropical islands

    NASA Astrophysics Data System (ADS)

    Sobel, A. H.; Burleyson, C. D.; Yuter, S. E.

    2011-04-01

    A high-resolution rainfall climatology based on observations from the Tropical Rainfall Measuring Mission's Precipitation Radar (PR) instrument is used to evaluate the influence of small tropical islands on climatological rainfall. Islands with areas between one hundred and several thousand km2 are considered in both the Indo-Pacific Maritime Continent and Caribbean regions. Annual mean climatological (1997-2007) rainfall over each island is compared with that over the surrounding ocean region, and the difference is expressed as a percentage. In addition to total rainfall, rain frequency and intensity are also analyzed. Results are stratified into two 12 h halves of the diurnal cycle as well as eight 3 h periods, and also by a measure of each island's topographic relief. In both regions, there is a clear difference between larger islands (areas of a few hundred km2 or greater) and smaller ones. Both rain frequency and total rainfall are significantly enhanced over larger islands compared to the surrounding ocean. For smaller islands the enhancement is either negligibly small, statistically insignificant, or, in the case of Caribbean rain frequency, negative. The enhancement in total rainfall over larger islands is partly attributable to greater frequency and partly to greater intensity. A diurnal cycle in island enhancement is evident in frequency but not intensity, except over small Caribbean islands where the converse is true. For the larger islands, higher orography is associated with greater rainfall enhancements. The orographic effect is larger (percentagewise) in the Caribbean than in the Maritime Continent. Orographic precipitation enhancement manifests more strongly as increased frequency of precipitation rather than increased intensity and is present at night as well as during the day. The lack of a clear diurnal cycle in orographic enhancement suggests that much of the orographic rainfall enhancement is attributable to mechanically forced upslope flow

  7. The critical slope for orographic rain

    NASA Astrophysics Data System (ADS)

    Breidenthal, Robert; Zagar, Nedjeljka

    2013-11-01

    Krishnamurti has shown that orographic rain depends on the slope of the windward terrain rather than just the total elevation gain. A simple physical model is proposed to account for the effect of slope. Based on the inhibiting effect of vortex (rotational) acceleration on entrainment, a critical slope angle is derived. If the rate of orographic lifting is sufficiently large, the enhanced buoyancy from latent heat release increases the acceleration parameter. As a consequence, the entrainment rate of under-saturated air is reduced. The critical slope corresponds to the situation where the rate of condensation in a rising adiabatic parcel just equals the rate of evaporation due to the entrainment of under-saturated air. The model is also applied to the trigger conditions for towering cumulus in general.

  8. The critical slope angle for orographic rain

    NASA Astrophysics Data System (ADS)

    Breidenthal, R. E.; Zagar, N.

    2013-12-01

    Krishnamurti has shown that orographic rain depends on the slope of the windward terrain rather than just the total elevation gain. A simple physical model is proposed to account for the effect of slope. Based on the inhibiting effect of vortex (rotational) acceleration on entrainment, a critical slope angle is derived. If the rate of orographic lifting is sufficiently large, the enhanced buoyancy from latent heat release increases the acceleration parameter. As a consequence, the entrainment rate of under-saturated air is reduced. The critical slope corresponds to the situation where the rate of condensation in a rising adiabatic parcel just equals the rate of evaporation due to the entrainment of under-saturated air. The model is also applied to the trigger conditions for towering cumulus in general.

  9. Development of one-minute rain-rate and rain-attenuation contour maps for satellite propagation system planning in a subtropical country: South Africa

    NASA Astrophysics Data System (ADS)

    Ojo, J. S.; Owolawi, P. A.

    2014-10-01

    Millimeter and microwave system design at higher frequencies require as input a 1-min rain-rate cumulative distribution function for estimating the level of degradation that can be encountered at such frequency bands. Owing to the lack of 1-min rain-rate data in South Africa and the availability of 5-min and hourly rainfall data, we have used rain-rate conversion models and the refined Moupfouma model to convert the available data into 1-min rain-rate statistics. The attenuation caused by these rain rates was predicted using the International Telecommunication Union (ITU) recommendations model. The Kriging interpolation method was used to draw contour maps over different percentages of time for spatial interpolation of rain-rate values into a regular grid in order to obtain a highly consistent and predictable inter-gauge rain-rate variation over South Africa. The present results will be useful for system designers of modern broadband wireless access (BWA) and high-density cell-based Ku/Ka, Q/V band satellite systems, over the desired area of coverage in order to determine the appropriate effective isotropically radiated power (EIRP) and receiver characteristics of this region.

  10. Integration of rain gauge measurement errors with the overall rainfall uncertainty estimation using kriging methods

    NASA Astrophysics Data System (ADS)

    Cecinati, Francesca; Moreno Ródenas, Antonio Manuel; Rico-Ramirez, Miguel Angel; ten Veldhuis, Marie-claire; Han, Dawei

    2016-04-01

    In many research studies rain gauges are used as a reference point measurement for rainfall, because they can reach very good accuracy, especially compared to radar or microwave links, and their use is very widespread. In some applications rain gauge uncertainty is assumed to be small enough to be neglected. This can be done when rain gauges are accurate and their data is correctly managed. Unfortunately, in many operational networks the importance of accurate rainfall data and of data quality control can be underestimated; budget and best practice knowledge can be limiting factors in a correct rain gauge network management. In these cases, the accuracy of rain gauges can drastically drop and the uncertainty associated with the measurements cannot be neglected. This work proposes an approach based on three different kriging methods to integrate rain gauge measurement errors in the overall rainfall uncertainty estimation. In particular, rainfall products of different complexity are derived through 1) block kriging on a single rain gauge 2) ordinary kriging on a network of different rain gauges 3) kriging with external drift to integrate all the available rain gauges with radar rainfall information. The study area is the Eindhoven catchment, contributing to the river Dommel, in the southern part of the Netherlands. The area, 590 km2, is covered by high quality rain gauge measurements by the Royal Netherlands Meteorological Institute (KNMI), which has one rain gauge inside the study area and six around it, and by lower quality rain gauge measurements by the Dommel Water Board and by the Eindhoven Municipality (six rain gauges in total). The integration of the rain gauge measurement error is accomplished in all the cases increasing the nugget of the semivariogram proportionally to the estimated error. Using different semivariogram models for the different networks allows for the separate characterisation of higher and lower quality rain gauges. For the kriging with

  11. Mechanics of Interrill Erosion with Wind-Driven Rain (WDR)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article provides an evaluation analysis for the performance of the interrill component of the Water Erosion Prediction Project (WEPP) model for Wind-Driven Rain (WDR) events. The interrill delivery rates (Di) were collected in the wind tunnel rainfall simulator facility of the International Cen...

  12. Acid rain. Rhetoric and reality

    SciTech Connect

    Park, C.

    1988-01-01

    The book examines the implications of recent scientific studies, and sets the political debate in the main 'polluting' countries--Britain and the United States--into its proper international context. It provides a wealth of U.S. data, including a history of the development of U.S. acid rain policy. The author presents a review of the evidence for damage and the statistics of change. Data is drawn from around the world, with particular emphasis on damage in Scandinavia and West Germany.

  13. Two groups challenge US acid rain efforts

    SciTech Connect

    Not Available

    1987-11-01

    In its report, Acid Rain Invades Our National Parks, the National Parks and Conservation Association (NPCA) says acid rain is being detected at all 27 national park monitoring sites. In 1980, 87 national parks expressed concern in a NPCA survey over acid rain. Repolled in 1986, more than half of the respondents reported that no research on acid rain was under way. The NPCA report concludes that the alarm that was sounded in 1980 fell largely on deaf ears, and calls for the structural and scientific reorganization of the National Park Service. The National Audubon Society shares NPCA's dissatisfaction with federal efforts to tackle the problem of acid rain and has taken testing into its own hands. Through its Citizens Acid Rain Monitoring Network, Audubon volunteers have collected readings of acidity at 64 monitoring stations in 31 states since July.

  14. Acid rain information book. Draft final report

    SciTech Connect

    1980-12-01

    Acid rain is one of the most widely publicized environmental issues of the day. The potential consequences of increasingly widespread acid rain demand that this phenomenon be carefully evaluated. Reveiw of the literature shows a rapidly growing body of knowledge, but also reveals major gaps in understanding that need to be narrowed. This document discusses major aspects of the acid rain phenomenon, points out areas of uncertainty, and summarizes current and projected research by responsible government agencies and other concerned organizations.

  15. Rain Effects on Radio Frequency Propagation

    DTIC Science & Technology

    1986-03-31

    ABSTRACT (Continue on reverse if necessary and identify by block number) Rain is a principal cause of signal degradation in a terrestrial or satellite trans...Predicted Attenuation, dB AS = Specific Rain Attenuation, dB/km av = Vertical Polarized Value of a Anooi A at 0.01% B = Satellite Beacon b = Empirical...Isotherm Height Ho = Height above Mean Sea Level, km Hr = the Rain Height, km ITU = International Telecommunications Union IWP = International

  16. Vibration (?) spikes during natural rain events

    NASA Technical Reports Server (NTRS)

    Short, David A.

    1994-01-01

    Limited analysis of optical rain gauge (ORG) data from shipboard and ground based sensors has shown the existence of spikes, possibly attributable to sensor vibration, while rain is occurring. An extreme example of this behavior was noted aboard the PRC#5 on the evening of December 24, 1992 as the ship began repositioning during a rain event in the TOGA/COARE IFA. The spikes are readily evident in the one-second resolution data, but may be indistinguishable from natural rain rate fluctuations in subsampled or averaged data. Such spikes result in increased rainfall totals.

  17. Soak Up the Rain: What's the Problem?

    EPA Pesticide Factsheets

    Why citizens and communities should soak up the rain with green infrastructure: to prevent water pollution, reduce flooding, protect water resources, beautify neighborhoods and other community benefits

  18. Acid rain threatens marine life

    SciTech Connect

    Not Available

    1988-09-01

    In freshwater, acid rain harms aquatic organisms because one of its components, sulfur dioxide, lowers the water's pH. In seawater, the damage comes from other components of acid precipitation: nitrogen oxides. Acting as a nutrient, nitrogen promotes excessive algal growth, which blocks sunlight and depletes dissolved oxygen, thereby suffocating other plants and animals. Known as eutrophication, this phenomenon has been increasing in both frequency and intensity on the Atlantic coast during the past few years. The New York City-based Environmental Defense Fund (EDF), study focused on the Chesapeake Bay, the nation's largest estuary and an important spawning ground for many species of economic importance. It has long been known that the bay is suffering from nitrogen pollution. Until now, it was assumed that most of the nitrogen was coming from sewage and agricultural runoff. However, based on data collected from both federal and state agencies, EDF scientists estimated that nitrates from acid rain are responsible for 25% of the nitrogen entering the bay. The report says that if present trends continue, airborne nitrates will contribute 42% of annual nitrogen deposits into the Chesapeake Bay by the year 2030.

  19. Rain from Tropical Storm Noel

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Though not the most powerful storm of the 2007 Atlantic Hurricane season, Tropical Storm Noel was among the most deadly. Only Category 5 Hurricane Felix and its associated flooding had a higher toll. The slow-moving Tropical Storm Noel inundated the Dominican Republic, Haiti, Jamaica, Cuba, and the Bahamas with heavy rain between October 28 and November 1, 2007. The resulting floods and mudslides left at least 115 dead and thousands homeless throughout the Caribbean, reported the Associated Press on November 2, 2007. This image shows the distribution of the rainfall that made Noel a deadly storm. The image shows rainfall totals as measured by the Multi-satellite Precipitation Analysis (MPA) at NASA Goddard Space Flight Center from October 26 through November 1, 2007. The analysis is based on measurements taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. The heaviest rainfall fell in the Dominican Republic and the Bahamas, northeast of Noel's center. Areas of dark red show that rainfall totals over the south-central Dominican Republic and parts of the Bahamas were over 551 millimeters (21 inches). Much of eastern Hispaniola, including both the Dominican Republic and Haiti received at least 200 mm (about 8 inches) of rain, shown in yellow. Rainfall totals over Haiti and Cuba were less, with a range of at least 50 mm (2 inches) to over 200 mm (8 inches).

  20. Flushing effect of rain on container-inhabiting mosquitoes Aedes aegypti and Culex pipiens (Diptera: Culicidae).

    PubMed

    Koenraadt, C J M; Harrington, L C

    2008-01-01

    We investigated the role of heavy rain on container-inhabiting mosquito (Diptera: Culicidae) populations, and how different species may have adapted to such conditions. Rains were created with a rain simulator calibrated to natural rain intensities in the habitats of two important vector species: Aedes aegypti (L.) from northern Thailand and Culex pipiens L. from New York state, USA. Immature stages of Ae. aegypti were able to resist the flushing effect of rain better than Cx. pipiens. This difference was most dramatic during the pupal stage. Fourth instars of Ae. aegypti were not affected by flushing when exposed for longer rain intervals (30 versus 60 min) or at a colder water temperature (24 versus 16 degrees C). In contrast, significantly more Cx. pipiens larvae flushed out with longer rain exposure. Warmer water temperatures also increased the proportion of Cx. pipiens flushed out, but mostly at the longest exposure time. Container position (tilted at a 7 degrees angle or level) did not affect proportions of fourth instars flushed out for both species. More accurate models of vector-borne diseases can be developed by incorporating the described effects of rain on container-breeding mosquito populations. Such models may provide more realistic assessments of disease risk and ensure optimal use of limited financial resources of mosquito control agencies.

  1. Rain effects on the hurricane observations over the ocean by C-band Synthetic Aperture Radar

    NASA Astrophysics Data System (ADS)

    Zhang, Guosheng; Li, Xiaofeng; Perrie, William; Zhang, Biao; Wang, Lei

    2016-01-01

    A composite radar scattering model composed of the atmosphere radiative transfer model, and the ocean surface Bragg wave theory is developed to analyze the impact of hurricane rain on the normalized radar-backscatter cross section (NRCS) measured in the VV and cross-polarized C-band Synthetic Aperture Radar (SAR) channels. The model results are validated against SAR and SFMR measured wind speeds and rain rates for two hurricane cases. The contribution of rain to the NRCS is backscatter from two parts: the atmosphere column and the ocean surface. In the atmosphere, microwave attenuation and the rain-induced volume backscattering are simulated by the model. We find that the impact of raindrops in the atmosphere is almost negligible for the VV polarization, but important for the cross polarization. On the ocean surface, comparisons between our model and other existing models without rain lead to the conclusion that the VV polarization NRCS can be simulated reasonably well without considering the non-Bragg scattering mechanisms. Similar to the wave breaking mechanism, the microwave diffraction on the craters, crowns, and stalks, produced by rain drops, is also negligible for VV polarization. However, the non-Bragg scattering is important for the cross-polarized NRCS simulations. Finally, we performed simulations to understand the VV-polarized NRCS behavior under different wind speeds at various rain rates.

  2. Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years

    PubMed Central

    Tng, David Y P; Murphy, Brett P; Weber, Ellen; Sanders, Gregor; Williamson, Grant J; Kemp, Jeanette; Bowman, David M J S

    2012-01-01

    Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO2 as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire

  3. Evaluation of TRMM Ground-Validation Radar-Rain Errors Using Rain Gauge Measurements

    NASA Technical Reports Server (NTRS)

    Wang, Jianxin; Wolff, David B.

    2009-01-01

    Ground-validation (GV) radar-rain products are often utilized for validation of the Tropical Rainfall Measuring Mission (TRMM) spaced-based rain estimates, and hence, quantitative evaluation of the GV radar-rain product error characteristics is vital. This study uses quality-controlled gauge data to compare with TRMM GV radar rain rates in an effort to provide such error characteristics. The results show that significant differences of concurrent radar-gauge rain rates exist at various time scales ranging from 5 min to 1 day, despite lower overall long-term bias. However, the differences between the radar area-averaged rain rates and gauge point rain rates cannot be explained as due to radar error only. The error variance separation method is adapted to partition the variance of radar-gauge differences into the gauge area-point error variance and radar rain estimation error variance. The results provide relatively reliable quantitative uncertainty evaluation of TRMM GV radar rain estimates at various times scales, and are helpful to better understand the differences between measured radar and gauge rain rates. It is envisaged that this study will contribute to better utilization of GV radar rain products to validate versatile spaced-based rain estimates from TRMM, as well as the proposed Global Precipitation Measurement, and other satellites.

  4. Fog and rain in the Amazon

    PubMed Central

    Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H.

    2015-01-01

    The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents. PMID:26324902

  5. Fog and rain in the Amazon

    NASA Astrophysics Data System (ADS)

    Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H.

    2015-09-01

    The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents.

  6. Fog and rain in the Amazon.

    PubMed

    Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H

    2015-09-15

    The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents.

  7. Differential evolution based prediction of rain attenuation over a LOS terrestrial link situated in the southern United Kingdom

    NASA Astrophysics Data System (ADS)

    Develi, Ibrahim

    2007-06-01

    The principal objective of a rain attenuation prediction method is to achieve acceptable estimates of the attenuation incurred on the signal due to rain. In this paper, a differential evolution (DE) based model for predicting rain attenuation in a terrestrial point-to-point line of sight (LOS) link at 97 GHz is proposed using previously available experimental data obtained in the southern United Kingdom. Rainfall rate and percentage of time are used as input data in the proposed prediction model. Excellent agreement between the experimental data and the model output indicates that the presented DE based method may efficiently be used for accurate prediction of the rain attenuation levels.

  8. The Rain Ratio Hypothesis: Can it be Rescued?

    NASA Astrophysics Data System (ADS)

    Munhoven, Guy

    2010-05-01

    The Rain Ratio Hypothesis (Archer and Maier-Reimer, 1994, Nature 367, 260-263) ascribes an important part of the observed glacial-interglacial variations of CO2 in the atmosphere to reduced sea-floor rain ratio (i.e., carbonate-C/organic-C in the biogenic particle flux at the sea-floor) during glacial times. With a lower sea-floor rain ratio the influence of organic carbon respiration on carbonate dissolution is stronger. The deep-sea carbonate ion concentration required for global ocean carbonate compensation will then be higher, which in turn contributes to lower atmospheric pCO2. Munhoven (2007, Deep-Sea Research II, 722-746) showed that the suggested rain ratio reductions lead to unrealistic sedimentary records for %CaCO3: the transition zone changes in the model sedimentary record were too large and opposite in phase to available observational data. The rain ratio reduction applied by Munhoven (2007) was uniform over the ocean and the author hypothesised that a non-uniform reduction could change the complete picture. If the rain ratio variations had primarily taken place in open ocean areas of great depth-essentially in regions where the sea floor was deeper than the saturation horizon or the CCD-then the transition zone boundaries could possibly have moved less. Here, we test this hypothesis and analyse the effect of depth dependent variations. It is shown that concentrating rain ratio changes over areas of greatest water depth completely alters the sedimentary imprint: the phase relationship of the signal reverts (compared to the uniform case) and the amplitude of the change decreases, bringing it into better agreement with the observations. However, the pCO2 response is also reduced. The global average rain ratio reduction of 40% that yielded a 40 ppm reduction of atmospheric pCO2 in the uniform case only leads to 25 ppm in this non-uniform case. Results for other depth-dependent reductions will also be discussed.

  9. Coastal and rain-induced wind variability depicted by scatterometers

    NASA Astrophysics Data System (ADS)

    Portabella, M.; Lin, W.; Stoffelen, A.; Turiel, A.; Verhoef, A.; Verspeek, J.; Ballabrera, J.; Vogelzang, J.

    2012-04-01

    A detailed knowledge of local wind variability near the shore is very important since it strongly affects the weather and microclimate in coastal regions. Since coastal areas are densely populated and most activity at sea occurs near the shore, sea-surface wind field information is important for a number of applications. In the vicinity of land sea-breeze, wave fetch, katabatic and current effects are more likely than in the open ocean, thus enhancing air-sea interaction. Also very relevant for air-sea interaction are the rain-induced phenomena, such as downbursts and convergence. Relatively cold and dry air is effectively transported to the ocean surface and surface winds are enhanced. In general, both coastal and rain-induced wind variability are poorly resolved by Numerical Weather Prediction (NWP) models. Satellite real aperture radars (i.e., scatterometers) are known to provide accurate mesoscale (25-50 km resolution) sea surface wind field information used in a wide variety of applications. Nowadays, there are two operating scatterometers in orbit, i.e., the C-band Advanced Scatterometer (ASCAT) onboard Metop-A and the Ku-band scatterometer (OSCAT) onboard Oceansat-2. The EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) delivers several ASCAT level 2 wind products with 25 km and 12.5 km Wind Vector Cell (WVC) spacing, including a pre-operational coastal wind product as well as an OSCAT level 2 wind product with 50 km spacing in development status. Rain is known to both attenuate and scatter the microwave signal. In addition, there is a "splashing" effect. The roughness of the sea surface is increased because of splashing due to rain drops. The so-called "rain contamination" is larger for Ku-band scatterometer systems than for C-band systems. Moreover, the associated downdrafts lead to variable wind speeds and directions, further complicating the wind retrieval. The C-band ASCAT high resolution wind processing is validated under rainy

  10. Pollen selection under acid rain stress

    SciTech Connect

    Zhang, Y.

    1994-01-01

    To investigate whether acid rain stress induces pollen selection in nature, three different approaches were used, based on the assumption that the response of pollen grains to acid rain is controlled by an acid sensitive gene product. Germination of pollen from homozygous and heterozygous individuals under acid rain stress was examined to detect any differences in rate of germination between populations of homogeneous and heterogeneous pollen grains. In vitro and in vivo bulked segregant analysis using RAPDs was used to search for differences in DNA constitution between the survivors of acid rain stressed and non-acid rain stressed pollen populations in vitro and between the progenies of acid rain stressed and non-acid rain stressed populations during pollination, respectively. No evidence for the pollen selection under acid rain stress was obtained in any of the test systems. Inhibition of protein synthesis using cycloheximide led to significant reduction of tube elongation at 4 hr and had no effect on pollen germination at any time interval tested. Total proteins extracted from control and acid rain stressed pollen grain populations exhibited no differences. The reduction of corn pollen germination in vitro under acid rain stress was mainly due to pollen rupture. The present data indicates the reduction of pollen germination and tube growth under acid rain stress may be a physiological response rather than a genetic response. A simple, nontoxic, and effective method to separate germinated from ungerminated pollen grains has been developed using pollen from corn (Zea mays, L. cv. Pioneer 3747). The separated germinated pollen grains retained viability and continued tube growth when placed in culture medium.

  11. Diversity gain for rain attenuation over Earth-space path at a tropical location

    NASA Astrophysics Data System (ADS)

    De, Arijit; Adhikari, Arpita; Maitra, Animesh

    2016-02-01

    The present study proposes a technique by which the diversity gain can be estimated for a site utilizing the propagation data obtained at a single station. The technique is crucial in estimating diversity parameters in the absence of multi-station data. The rain decay parameter, as defined in the Simple Attenuation Model (SAM), is used to derive the rain rate and consequently rain attenuation at different distances from the single receiving site. The tropical location has been found to experience a wide variability of rain features during different periods of the year causing strong seasonal variations in the diversity gain. A comparison of the diversity gain obtained from the present propagation data and the ITU-R model indicates the necessity of modifying the model parameters of the ITU-R model. The modified model incorporates the seasonal variation and exhibits better prediction capability than the ITU-R model as related to the tropical location.

  12. Energy technology and emissions control for acid rain abatement in Asia

    SciTech Connect

    Streets, D.G.

    1990-01-01

    After more than ten years of research, acid rain is a sufficiently serious problem in North America to warrant control action. The acid rain problem has become a threat to the Asian continent as well. Emissions of sulfur dioxide and nitrogen oxides are already high and announces plans for increases in coal use by countries in the region imply a major increase in emissions in the future. This will inevitably lead to greater incidence of acid rain and probably significant environmental damage in some locations. The purpose of this paper is to examine some of the issues relating to acid-rain-control technology in Asia and to suggest ways to include technology options in integrated simulation models of acid rain in Asia. 14 refs., 9 figs., 6 tabs. (FL)

  13. Desert Dust and Monsoon Rain

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, Kyu-Myong

    2014-01-01

    For centuries, inhabitants of the Indian subcontinent have know that heavy dust events brought on by strong winds occur frequently in the pre-monsoon season, before the onset of heavy rain. Yet scientists have never seriously considered the possibility that natural dust can affect monsoon rainfall. Up to now, most studies of the impacts of aerosols on Indian monsoon rainfall have focused on anthropogenic aerosols in the context of climate change. However, a few recent studies have show that aerosols from antropogenic and natural sources over the Indian subcontinent may affect the transition from break to active monsoon phases on short timescales of days to weeks. Writing in Nature Geoscience, Vinoj and colleagues describe how they have shown that desert dust aerosols over the Arabian Sea and West Asia can strenghten the summer monsoon over the Indial subcontinent in a matter of days.

  14. Rain underscores need for injection

    SciTech Connect

    Stelling, K.F.

    1996-01-01

    Since 1987, steam production totals at The Geysers Geothermal field have fallen and water injection totals have remained quite stable, except for the unusually dry winter months of 1994 when injection fell by a record amount. The heavy rainfall in the first half of 1995 altered the long-term production and injection patterns and underscored the need to increase injection in the field. From January to June 1995, steam production at The Geysers was reduced by 37 percent form the amount produced during the same period in 1994--because the rain increased availability of hydroelectric power. At the same time, water injection in the field rose by 25 percent because more rainwater was available for injection. Consequently, both reservoir pressure and available steam reserves grew, and most power plants that returned on line in the second half of the year produced more megawatts with less steam. This confirmed findings form several injection studies at The Geyser`s.

  15. Rain garden guidelines for southwest Ohio

    EPA Science Inventory

    Rain gardens are a unique and practical landscape feature that can enhance the beauty of home gardens. When properly installed, they are one method of limiting the negative effects of rainfall runoff in urban areas. Indeed, rain gardens turn a "negative" into a "positive" by capt...

  16. Rainy Day Fun: Rain-Inspired Activities.

    ERIC Educational Resources Information Center

    Stanger, Annie Moretz

    1999-01-01

    Rainy days are opportunities to teach campers about weather and to plan activities around a rain theme. Indoor and outdoor science-based activities concerned with rain, water, or water conservation are suggested for specific age groups from ages 5-7 through 11-14. Campers can also develop ideas for activities using questions provided. (CDS)

  17. Human Ecology: Acid Rain and Public Policy.

    ERIC Educational Resources Information Center

    Bybee, Rodger W.

    1983-01-01

    A connection between science and society can be seen in the human and ecological dimensions of one contemporary problem: acid rain. Introduces a human ecological theme and relationships between acid rain and public policy, considering scientific understanding and public awareness, scientific research and public policy, and national politics and…

  18. Acid Rain Students Do Original Research.

    ERIC Educational Resources Information Center

    Outdoor Communicator, 1984

    1984-01-01

    At Park Senior High School (Cottage Grove, Minnesota), 46 juniors and seniors planted 384 red pine seedlings in connection with their original research on acid rain, with advice from Dr. Harriet Stubbs, director of the Acid Precipitation Awareness Program (West Saint Paul), which has been developing acid rain teaching materials. (MH)

  19. Acid Rain. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Hollmann, Pauline, Comp.

    The term "acid rain," also called "acid precipitation," generally refers to any precipitation having a pH value of less than 5.6. This guide to the literature on acid rain in the collections of the Library of Congress is not necessarily intended to be a comprehensive bibliography. It is designed to provide the reader with a set…

  20. Acid Rain: Activities for Science Teachers.

    ERIC Educational Resources Information Center

    Johnson, Eric; And Others

    1983-01-01

    Seven complete secondary/college level acid rain activities are provided. Activities include overview; background information and societal implications; major concepts; student objectives; vocabulary/material lists; procedures; instructional strategies; and questions/discussion and extension suggestions. Activities consider effects of acid rain on…

  1. Acid Thunder: Acid Rain and Ancient Mesoamerica

    ERIC Educational Resources Information Center

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  2. Environmental Education about the Rain Forest.

    ERIC Educational Resources Information Center

    Berkmuller, Klaus

    Designed to help in the development of an educational program about the value of rain forests, this handbook presents a condensation of issues, facts, and concepts. The handbook is divided into three parts. Part one introduces the rain forest ecosystem and provides conceptual background material needed in the determination of problems, the…

  3. GREEN INFRASTRUCTURE RESEARCH PROGRAM: Rain Gardens

    EPA Science Inventory

    the National Risk Management Research Laboratory (NRMRL) rain garden evaluation is part of a larger collection of long-term research that evaluates a variety of stormwater management practices. The U.S. EPA recognizes the potential of rain gardens as a green infrastructure manag...

  4. Automated rain rate estimates using the Ka-band ARM zenith radar (KAZR)

    NASA Astrophysics Data System (ADS)

    Chandra, A.; Zhang, C.; Kollias, P.; Matrosov, S.; Szyrmer, W.

    2015-09-01

    The use of millimeter wavelength radars for probing precipitation has recently gained interest. However, estimation of precipitation variables is not straightforward due to strong signal attenuation, radar receiver saturation, antenna wet radome effects and natural microphysical variability. Here, an automated algorithm is developed for routinely retrieving rain rates from the profiling Ka-band (35-GHz) ARM (Atmospheric Radiation Measurement) zenith radars (KAZR). A 1-dimensional, simple, steady state microphysical model is used to estimate impacts of microphysical processes and attenuation on the profiles of radar observables at 35-GHz and thus provide criteria for identifying situations when attenuation or microphysical processes dominate KAZR observations. KAZR observations are also screened for signal saturation and wet radome effects. The algorithm is implemented in two steps: high rain rates are retrieved by using the amount of attenuation in rain layers, while low rain rates are retrieved from the reflectivity-rain rate (Ze-R) relation. Observations collected by the KAZR, rain gauge, disdrometer and scanning precipitating radars during the DYNAMO/AMIE field campaign at the Gan Island of the tropical Indian Ocean are used to validate the proposed approach. The differences in the rain accumulation from the proposed algorithm are quantified. The results indicate that the proposed algorithm has a potential for deriving continuous rain rate statistics in the tropics.

  5. The Study of Rain Specific Attenuation for the Prediction of Satellite Propagation in Malaysia

    NASA Astrophysics Data System (ADS)

    Mandeep, J. S.; Ng, Y. Y.; Abdullah, H.; Abdullah, M.

    2010-06-01

    Specific attenuation is the fundamental quantity in the calculation of rain attenuation for terrestrial path and slant paths representing as rain attenuation per unit distance (dB/km). Specific attenuation is an important element in developing the predicted rain attenuation model. This paper deals with the empirical determination of the power law coefficients which allow calculating the specific attenuation in dB/km from the knowledge of the rain rate in mm/h. The main purpose of the paper is to obtain the coefficients of k and α of power law relationship between specific attenuation. Three years (from 1st January 2006 until 31st December 2008) rain gauge and beacon data taken from USM, Nibong Tebal have been used to do the empirical procedure analysis of rain specific attenuation. The data presented are semi-empirical in nature. A year-to-year variation of the coefficients has been indicated and the empirical measured data was compared with ITU-R provided regression coefficient. The result indicated that the USM empirical measured data was significantly vary from ITU-R predicted value. Hence, ITU-R recommendation for regression coefficients of rain specific attenuation is not suitable for predicting rain attenuation at Malaysia.

  6. Rain reverses diel activity rhythms in an estuarine teleost

    PubMed Central

    Payne, Nicholas L.; van der Meulen, Dylan E.; Gannon, Ruan; Semmens, Jayson M.; Suthers, Iain M.; Gray, Charles A.; Taylor, Matthew D.

    2013-01-01

    Activity rhythms are ubiquitous in nature, and generally synchronized with the day–night cycle. Several taxa have been shown to switch between nocturnal and diurnal activity in response to environmental variability, and these relatively uncommon switches provide a basis for greater understanding of the mechanisms and adaptive significance of circadian (approx. 24 h) rhythms. Plasticity of activity rhythms has been identified in association with a variety of factors, from changes in predation pressure to an altered nutritional or social status. Here, we report a switch in activity rhythm that is associated with rainfall. Outside periods of rain, the estuarine-associated teleost Acanthopagrus australis was most active and in shallower depths during the day, but this activity and depth pattern was reversed in the days following rain, with diurnality restored as estuarine conductivity and turbidity levels returned to pre-rain levels. Although representing the first example of a rain-induced reversal of activity rhythm in an aquatic animal of which we are aware, our results are consistent with established models on the trade-offs between predation risk and foraging efficiency. PMID:23173211

  7. Rain reverses diel activity rhythms in an estuarine teleost.

    PubMed

    Payne, Nicholas L; van der Meulen, Dylan E; Gannon, Ruan; Semmens, Jayson M; Suthers, Iain M; Gray, Charles A; Taylor, Matthew D

    2013-01-07

    Activity rhythms are ubiquitous in nature, and generally synchronized with the day-night cycle. Several taxa have been shown to switch between nocturnal and diurnal activity in response to environmental variability, and these relatively uncommon switches provide a basis for greater understanding of the mechanisms and adaptive significance of circadian (approx. 24 h) rhythms. Plasticity of activity rhythms has been identified in association with a variety of factors, from changes in predation pressure to an altered nutritional or social status. Here, we report a switch in activity rhythm that is associated with rainfall. Outside periods of rain, the estuarine-associated teleost Acanthopagrus australis was most active and in shallower depths during the day, but this activity and depth pattern was reversed in the days following rain, with diurnality restored as estuarine conductivity and turbidity levels returned to pre-rain levels. Although representing the first example of a rain-induced reversal of activity rhythm in an aquatic animal of which we are aware, our results are consistent with established models on the trade-offs between predation risk and foraging efficiency.

  8. Household response to environmental incentives for rain garden adoption

    NASA Astrophysics Data System (ADS)

    Newburn, David A.; Alberini, Anna

    2016-02-01

    A decentralized approach to encourage the voluntary adoption of household stormwater management practices is increasingly needed to mitigate urban runoff and to comply with more stringent water quality regulations. We analyze the household response to a hypothetical rebate program to incentivize rain garden adoption using household survey data from the Baltimore-Washington corridor. We asked respondents whether the household would adopt a rain garden without a rebate or when offered a randomly assigned rebate. An interval-data model is used to estimate household demand on the willingness to pay (WTP) for a rain garden as a function of demographic factors, gardening activities, environmental attitudes, and other household characteristics. Estimation results indicate that mean WTP for a rain garden in our sample population is approximately $6.72 per square foot, corresponding to almost three-fourths of the installation cost. The expected adoption rate more than tripled when comparing no rebate versus a government rebate set at one-third of the installation cost, indicating that economic incentives matter. There is substantial heterogeneity in the WTP among households. Higher levels of WTP are estimated for households with higher environmental concern for the Chesapeake Bay and local streams, garden experience, higher income, and non-senior citizen adults. We conclude that a cost-share rebate approach is likely to significantly affect household adoption decisions, and the partial contributions paid by households can assist with lowering the substantial compliance costs for local governments to meet water quality requirements.

  9. Acid Rain: A Teaching Focus for the Intermediate Grades.

    ERIC Educational Resources Information Center

    Adams, Renee B.; Adams, Neil D.

    1992-01-01

    The study of acid rain provides ample opportunities for active, interdisciplinary learning. This article describes 12 hands-on activities designed to expand students' understanding of acid rain. Background information on acid rain is included. (LB)

  10. What You Can Do to Soak Up the Rain

    EPA Pesticide Factsheets

    Take steps around your home and community to reduce stormwater runoff. Use rain barrels, disconnect/redirect downspouts, plant trees and rain gardens, use drywells and permeable pavers, and plant green roofs. Take action to soak up the rain.

  11. Rain-induced subsurface airflow and Lisse effect

    USGS Publications Warehouse

    Guo, H.; Jiao, J.J.; Weeks, E.P.

    2008-01-01

    Water-level increase after rainfall is usually indicative of rainfall recharge to groundwater. This, however, may not be true if the Lisse effect occurs. This effect represents the water-level increase in a well driven by airflow induced by an advancing wetting front during highly intensive rains. The rainwater, which may behave like a low-permeability lid, seals the ground surface so that the air pressure beneath the wetting front is increased because of air compression due to downward movement of the wetting front. A rapid and substantial rise of the water level in the well screened below water table, which bears no relationship to groundwater recharge, can be induced when various factors such as soil properties and the rain-runoff condition combine favorably. A transient, three-dimensional and variably saturated flow model was employed to study the air and groundwater flows in the soil under rain conditions. The objectives of this paper are two-fold: to evaluate the reliability of the theory of the Lisse effect presented by Weeks to predict its magnitude in modeled situations that mimic the physical complexity of real aquifers, and to conduct parametric studies on the sensitivity of the water-level rise in the well to soil properties and the rain event. The simulation results reveal that the magnitude of the Lisse effect increases with the ponding depth. Soil permeability plays a key role in generating the Lisse effect. The water-level rise in the well is delayed relative to the air-pressure rise in the unsaturated zone when the soil permeability is low, and the maximum water-level rise is less than the maximum air pressure induced by rain infiltration. The simulation also explores the sensitivity of the Lisse effect to the van Genuchten parameters and the water table depth. Copyright 2008 by the American Geophysical Union.

  12. Survival probability of precipitations and rain attenuation in tropical and equatorial regions

    NASA Astrophysics Data System (ADS)

    Mohebbi Nia, Masoud; Din, Jafri; Panagopoulos, Athanasios D.; Lam, Hong Yin

    2015-08-01

    This contribution presents a stochastic model useful for the generation of a long-term tropospheric rain attenuation time series for Earth space or a terrestrial radio link in tropical and equatorial heavy rain regions based on the well-known Cox-Ingersoll-Ross model previously employed in research in the fields of finance and economics. This model assumes typical gamma distribution for rain attenuation in heavy rain climatic regions and utilises the temporal dynamic of precipitation collected in equatorial Johor, Malaysia. Different formations of survival probability are also discussed. Furthermore, the correlation between these probabilities and the Markov process is determined, and information on the variance and autocorrelation function of rain events with respect to the particular characteristics of precipitation in this area is presented. The proposed technique proved to preserve the peculiarities of precipitation for an equatorial region and reproduce fairly good statistics of the rain attenuation correlation function that could help to improve the prediction of dynamic characteristics of rain fade events.

  13. Use of inverse modeling to evaluate CENTURY-predictions for soil carbon sequestration in US rain-fed corn production systems

    PubMed Central

    Ugarte, Carmen M.; Ogle, Stephen M.; Williams, Stephen A.; Wander, Michelle M.

    2017-01-01

    We evaluated the accuracy and precision of the CENTURY soil organic matter model for predicting soil organic carbon (SOC) sequestration under rainfed corn-based cropping systems in the US. This was achieved by inversely modeling long-term SOC data obtained from 10 experimental sites where corn, soybean, or wheat were grown with a range of tillage, fertilization, and organic matter additions. Inverse modeling was accomplished using a surrogate model for CENTURY’s SOC dynamics sub-model wherein mass balance and decomposition kinetics equations from CENTURY are coded and solved by using a nonlinear regression routine of a standard statistical software package. With this approach we generated statistics of CENTURY parameters that are associated with the effects of N fertilization and organic amendment on SOC decay, which are not as well quantified as those of tillage, and initial status of SOC. The results showed that the fit between simulated and observed SOC prior to inverse modeling (R2 = 0.41) can be improved to R2 = 0.84 mainly by increasing the rate of SOC decay up to 1.5 fold for the year in which N fertilizer application rates are over 200 kg N ha-1. We also observed positive relationships between C inputs and the rate of SOC decay, indicating that the structure of CENTURY, and therefore model accuracy, could be improved by representing SOC decay as Michaelis-Menten kinetics rather than first-order kinetics. Finally, calibration of initial status of SOC against observed levels allowed us to account for site history, confirming that values should be adjusted to account for soil condition during model initialization. Future research should apply this inverse modeling approach to explore how C input rates and N abundance interact to alter SOC decay rates using C inputs made in various forms over a wider range of rates. PMID:28234992

  14. Development of a Visualization Rain Table: A Hard Rain's A-Gonna Fall

    NASA Astrophysics Data System (ADS)

    Kirkby, K. J.; Svistula, D.; Currier, R. M.; Morin, P. J.; Campbell, K.; Leigh, J.; Johnson, A.

    2007-12-01

    At first glance, water flow seems like such a deceptively simple concept. Water flows downhill, so what could be easier to understand? But the movement of water across the Earth's surface is among the most misunderstood and underestimated concepts in earth science. A host of misconceptions bound concerning water flow, from rivers always flowing south or curving due to the Earth's spin, to deeply held ideas about rivers" immutable nature. The one consistent aspect is that students almost always underestimate the complexity of water flow. The movement of water across the Earth is the integrating connection between its physical and biological systems. Combine these misconceptions with the realization that water use issues will be among the most crucial and complex social and political issues facing the next generation and it is difficult to overstate the importance of being able to teach a good understanding of natural water flow. Without a doubt, the best way to understand water flow is to watch the movement of water across the Earth's surface, but this has not been possible in past classroom settings. Physical models help, but are a poor substitute for the complexities of real world flow. In addition, it can be extraordinarily difficult for students to scale up from small physical models to real life stream flow. Rain Table is a tiled display system that uses six 30" flat panel monitors to display a large image of a region of the Earth's surface. This large image is co-registered with digital elevation data, so as students generate rainfall, the water will "flow" across the area, following the topography of the visualized region. Students move small disc-shaped devices across the panel surface to determine where rain should fall. The rain is displayed as small blue dots that flow down across the surface in accordance with the digital elevation data. Mathematical algorithms determine the water flow velocity based on the slope of the visualized surface and from the

  15. A TRMM Microwave Radiometer Rain Rate Estimation Method with Convective and Stratiform Discrimination

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Weinman, J. A.; Dalu, G.

    1999-01-01

    Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) radiometer brightness temperature data in the 85 GHz channel (T85) reveal distinct local minima (T85min) in a regional map containing a Mesoscale Convective System (MCS). This is because of relatively small footprint size (approximately 5.5 km) and strong extinction properties in this channel of the TMI. A map of surface rain rate for that region, deduced from simultaneous measurements made by the Precipitation Radar (PR) on board the TRMM satellite, reveals that these T85(sub min), produced by scattering, correspond to local PR rain maxima. Utilizing the PR rain rate map as a guide, we infer empirically from TMI data the presence of three different kinds of thunderstorms or Cbs. These Cbs are classified as young, mature, and decaying types, and are assumed to have a scale of about 20 km on the average. Two parameters are used to classify these three kinds of Cbs based on the T85 data: a) the magnitude of scattering depression deduced from local T85(sub min) and b) the mean horizontal gradient of T85 around such minima. Knowing the category of a given Cb, we can estimate the rain rate associated with it. Such estimation is done with the help of relationships linking T85min to rain rate in each Cb type. Similarly, a weak background rain rate in all the areas where T85 is less than 260 K is deduced with another relationship linking T85 to rain rate. In our rain retrieval model, this background rain constitutes stratiform rain where the Cbs are absent. Initially, these relationships are optimized or tuned utilizing the PR and TMI data of a few MCS events. After such tuning, the model is applied to independent MCS cases. The areal distribution of light (1-10 mm/hr), moderate (10-20 mm/hr), and intense (>= 20 mm/hr) rain rates are retrieved satisfactorily. Accuracy in the estimates of the light, moderate, and intense rain areas and the mean rain rates associated with such areas in these independent MCS

  16. TMI Rain Rate Estimation Over Land and Ocean Utilizing Convective and Stratiform Discrimination

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Weinman, J. A.; Dalu, G.

    1999-01-01

    Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) radiometer brightness temperature data in the 85 GHz channel (T85) reveal distinct local minima in a regional map containing a Mesoscale Convective System (MCS). This is because of relatively small footprint size (approximately 5.5 km) and strong extinction properties in this channel of the TMI. A map of rain rate for that region, deduced from simultaneous measurements made by the Precipitation Radar (PR) on board the TRMM satellite, reveals that these T85 minima, produced by scattering, correspond to local PR rain maxima. Utilizing the PR rain rate map as a guide, we infer from TMI data the presence of three different kinds of thunderstorms or Cbs. They are young, mature, and decaying Cbs that have a scale of about 20 km on the average. Two parameters enable us to infer these three kinds of Cbs objectively: a) the magnitude of scattering depression deduced from local T85 minima and b) the mean horizontal gradient of T85 around such minima. Knowing the category of a given Cb, we can estimate the rain rate associated with it. Such estimation is done with the help of relationships linking T85 minimum to rain rate in each Cb type. Similarly, a weak background rain rate in all the areas where T85 is less than 260 K is deduced with another relationship linking T85 to rain rate. In our rain retrieval model, this background rain constitutes the stratiform rain where the Cbs are absent. Initially, these relationships are optimized or tuned utilizing the PR and TMI data of a few MCS events. After such tuning, the model is applied to independent MCS cases. The areal distribution of light (1-10 mm/hr), moderate (10-20 mm/hr), and intense (> 20 mm/hr) rain rates are retrieved satisfactorally. Accuracy in the estimates of the light, moderate and intense rain areas and the mean rain rates associated with such areas in these independent MCS cases is on the average about 15%. Taking advantage of this ability of our

  17. Verification of wind fields by means of rain cell tracking

    NASA Astrophysics Data System (ADS)

    Herbort, F.

    2009-09-01

    VERIFICATION OF WIND FIELDS BY MEANS OF RAIN CELL TRACKING Herbort, F., Knigge, C. and Etling, D, Institute of Meteorology and Climatology, Leibniz University Hannover,Germany herbort@muk.uni-hannover.de The regional weather forecast model COSMO-DE of the German weather service is run at a spatial resolution of 2.8 km. This results in rather detailed simulations of meteorological fields like pressure, temperature and wind. In contrast, for verification of those NWP products outside the atmospheric surface layer, only a few radiosonde stations can provide the necessary observations. In order to improve the spatial and temporal resolution of observed wind fields we propose a new method based on the motion of rain cells as observed by the German rain radar network. The radar product consist of the radar reflectivity over Germany caused by hydrometeors with a spatial resolution of about 1 km and a temporal resolution of 5 minutes. The tracking of localised radar echoes caused by post frontal showers has been used for statistical analysis of rain showers in earlier work at our institute (Weusthoff and Hauf,2008). The fields of radar reflectivity are analysed in our work by the so-called PIV (Particle Image Velocimetry) method as used in experimental fluid mechanics for obtaining velocity fields of flow phenomena. Instead of solid particles as used as tracking objects in laboratory flows we use the localised radar reflectivities caused by the rain showers as tracer particles for the PIV method. The PIV algorithm provides two dimensional wind fields in the area of Germany with a few kilometres spatial resolution. The observed wind fields are compared to the wind fields obtained by the COSMO-DE model at several vertical levels in the lowest 4 kilometres of the atmosphere. By this way we could not only obtain some estimates for the skill of the wind field forecasts of the model but also could provide information on the most suitable model level for wind forecast

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

    NASA Technical Reports Server (NTRS)

    Tohda, Motofumi

    1997-01-01

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

  19. The urban perspectives of acid rain. Workshop summary

    SciTech Connect

    Tonn, B.E.

    1993-06-04

    This report documents discussions held during a workshop an Urban Perspective of Acid Rain. The workshop was sponsored by the Office of the Director, National Acid Precipitation Assessment Program (NAPAP). NAPAP anticipates giving increased emphasis to the benefits in urban areas of emissions reductions. The goal of this informal, exploratory workshop was to serve as a first step towards identifying pollutant monitoring, and research and assessment needs to help answer, from an urban perspective, the two key questions posed to NAPAP by Congress: (1) what are the costs, benefits, and effectiveness of the acid rain control program, and (2) what reductions in deposition, rates are needed in order to prevent adverse effects? The workshop addressed research activities needed to respond to these questions. The discussions focused. sequentially, on data needs, data and model availability, and data and modeling gaps. The discussions concentrated on four areas of effects: human health, materials, urban forests, and visibility.

  20. TECHNOLOGICAL OPTIONS FOR ACID RAIN CONTROL

    EPA Science Inventory

    Discussed are acid rain control options available to the electric utility industry. They include coal switching, flue gas desulfurization, and such emerging lower cost technologies as Limestone Injection Multistage Burners (LIMB) and Advanced Silicate (ADVACATE), both developed ...

  1. Soak Up the Rain Customizable Outreach Tools

    EPA Pesticide Factsheets

    Get customizable Soak Up the Rain business card, posters, & a banner that can be downloaded & copied for use by citizens, municipalities, watershed & planning organizations & others in their stormwater/green infrastructure education & outreach efforts.

  2. Validation of Rain Rate Retrievals for the Airborne Hurricane Imaging Radiometer (HIRAD)

    NASA Technical Reports Server (NTRS)

    Jacob, Maria Marta; Salemirad, Matin; Jones, W. Linwood; Biswas, Sayak; Cecil, Daniel

    2015-01-01

    corresponding theoretical Tb values from a forward radiative transfer model (RTM). The optimum solution is the integrated rain rate that minimizes the difference between RTM and observed values. Because the excess Tb from rain comes from the direct upwelling and the indirect reflected downwelling paths through the atmosphere, there are several assumptions made for the 2D rain distribution in the antenna incident plane (crosstrack to flight direction). The opportunity to knowing 2D rain surface truth from NEXRAD at two different altitudes will enable a comprehensive evaluation to be preformed and reported in this paper.

  3. Differentiating between rain, snow, and glacier contributions to river discharge in the western Himalaya using remote-sensing data and distributed hydrological modeling

    NASA Astrophysics Data System (ADS)

    Wulf, Hendrik; Bookhagen, Bodo; Scherler, Dirk

    2016-02-01

    Rivers draining the southern Himalaya provide most of the water supply for the densely populated Indo-Gangetic plains. Despite the importance of water resources in light of climate change, the relative contributions of rainfall, snow and glacier melt to discharge are not well understood, due to the scarcity of ground-based data in this complex terrain. Here, we quantify discharge sources in the Sutlej Valley, western Himalaya, from 2000 to 2012 with a distributed hydrological model that is based on daily, ground-calibrated remote-sensing observation. Based on the consistently good model performance, we analyzed the spatiotemporal distribution of hydrologic components and quantified their contribution to river discharge. Our results indicate that the Sutlej River's annual discharge at the mountain front is sourced to 55% by effective rainfall (rainfall reduced by evapotranspiration), 35% by snow melt and 10% by glacier melt. In the high-elevation orogenic interior glacial runoff contributes ∼30% to annual river discharge. These glacier melt contributions are especially important during years with substantially reduced rainfall and snowmelt runoff, as during 2004, to compensate for low river discharge and ensure sustained water supply and hydropower generation. In 2004, discharge of the Sutlej River totaled only half the maximum annual discharge; with 17.3% being sourced by glacier melt. Our findings underscore the importance of calibrating remote-sensing data with ground-based data to constrain hydrological models with reasonable accuracy. For instance, we found that TRMM (Tropical Rainfall Measuring Mission) product 3B42 V7 systematically overestimates rainfall in arid regions of our study area by a factor of up to 5. By quantifying the spatiotemporal distribution of water resources we provide an important assessment of the potential impact of global warming on river discharge in the western Himalaya. Given the near-global coverage of the utilized remote

  4. NASA's DC-8 With Rain Mapping Radar

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In a joint venture between NASA and Japan's NASDA, scientists have been using satellites, airplanes, and boats to measure rain physics in and under thunderstorms over open water. This Quick Time movie shows NASA's DC-8 jet with the instruments like the airborne rain mapping radar, i.e., the Advanced Microwave Precipitation Radiometer (AMPR) and a lightening imaging sensor. Earth science and weather studies are an important ongoing function of NASA and its affiliates.

  5. Raine syndrome: expanding the radiological spectrum.

    PubMed

    Koob, Mériam; Doray, Bérénice; Fradin, Mélanie; Astruc, Dominique; Dietemann, Jean-Louis

    2011-03-01

    We describe ante- and postnatal imaging of a 1-year-old otherwise healthy girl with Raine syndrome. She presented with neonatal respiratory distress related to a pyriform aperture stenosis, which was diagnosed on CT. Signs of chondrodysplasia punctata, sagittal vertebral clefting and intervertebral disc and renal calcifications were also found on imaging. This new case confirms that Raine syndrome is not always lethal. The overlapping imaging signs with chondrodysplasia punctata and the disseminated calcifications give new insights into its pathophysiology.

  6. Warm Rain Processes Over the Tropical Oceans and Implications on Climate Change

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, H. T.

    2004-01-01

    In this talk, we will first show results from TRMM regarding the characteristics of warm rains over the tropical oceans, and the dependence of rate of warm rain production on sea surface temperature. Results lead to the hypothesis that warm rain production efficiency, i.e., autoconversion, may be increased in a warm climate. We use the GEOS-II GCM to test this hypothesis. Our modeling results show that in a climate with increased rate of autoconversion, the total rain amount is increased, with warm rain contributing to a larger portion of the increase. The abundant rainout of warm precipitation at middle to low levels causes a reduction of high cloud cover due to the depletion of water available for ice-phase rain production. As a result, more isolated, but more intense penetrative convection develops. Results also show that increased autoconversion reduces the convective adjustment time scale tends, implying a faster recycling of atmospheric water. Most interestingly, the increased low level heating associated with warm rain leads to more energetic Madden and Julian oscillations in the tropics, with well-defined eastward propagation. While reducing the autoconversion leads to an abundant mix of westward and eastward tropical disturbance on daily to weekly time scales. The causes of the sensitivity of the dynamical regimes to the microphysics parameterization in the GCM will be discussed.

  7. Effects of acid rain on grapevines

    SciTech Connect

    Forsline, P.L.; Musselman, R.C.; Dee, R.J.; Kender, W.J.

    1983-01-01

    Mature vineyard-growing Concord grapevines were sprayed with simulated acid rain solutions ranging from pH 2.5 to 5.5 both as acute treatments at anthesis and chronically throughout the season in 1980 and 1981. In 1981, 8 additional varieties were also treated with simulated acid rain solutions at pH 2.75 and 3.25. With Concord in 1981, few foliar lesions on leaves were visible at pH 2.75. In contrast, many leaf lesions with decreased fruit soluble solids were observed at pH 2.5 in 1980. The relationship between acid-rain and oxidant stipple, chlorosis, and soluble solids in the absence of acid rain leaf lesions at pH>2.5 remains unclear. Acute sprays (pH2.75) at anthesis reduced pollen germination in four grape cultivars. However, fruit set was reduced in only one of these. Grape yields were not influenced by acid rain treatments. There was no evidence that acid-rain at ambient pH levels had negative effects on grape production or fruit quality.

  8. Effects of acid rain on grapevines

    SciTech Connect

    Forsline, P.L.; Musselman, R.C.; Dee, R.J.; Kender, W.J.

    1983-01-01

    Mature vineyard-growing Concord grapevines (Vitis labrusca, Bailey) were sprayed with simulated acid rain solutions ranging from pH 2.5 to pH 5.5 both as acute treatments at anthesis and chronically throughout the season in 1980 and 1981. In 1981, eight additional varieties were also treated with simulated acid rain solutions at pH 2.75 and pH 3.25. With Concord in 1981, few foliar lesions on leaves were visible at pH 2.75. In contrast, many leaf lesions with decreased fruit soluble solids in the absence of acid rain leaf lesions at pH>2.5 remains unclear. Acute sprays (pH 2.75) at anthesis reduced pollen germination in four grape cultivars. However, fruit set was reduced in only one of these. Only the cultivars de Chaunac and Ives had reduced berry soluble solids with chronic weekly sprays at pH 2.75. Reduction in soluble solids was not associated with increased oxidant stipple (ozone injury) in Concord and de Chaunac cultivars, but this association was observed in Ives. There was no evidence that acid rain in combination with ozone increased oxidant stipple as occurs when ozone and SO/sub 2/ are combined. Grape yields were not influenced by acid rain treatments. There was no evidence that acid rain at ambient pH levels had negative effects on grape production or fruit quality.

  9. Modeling of tropospheric integrated water vapor content using GPS, radiosonde, radiometer, rain gauge, and surface meteorological data in a tropical region (French Polynesia)

    NASA Astrophysics Data System (ADS)

    Serafini, Jonathan; Barriot, Jean-Pierre; Hopuare, Marania; Sichoix, Lydie; Fadil, Abdelali

    2012-11-01

    The integrated precipitable water vapor (IPW) is characterized by strong spatial and temporal variability, especially over tropical regions where the troposhere is not purely in hydrostatic equilibrium (convection). As an evidence, the survey of water vapor distibution as permanently as possible is an important issue and should serve as inputs for tropical climate modelling. In this paper, we present an estimation of the IPV from ground­ ba,.sed GPS receivers, which we compare to radiosondes and microwave radiometer. The data used here were collected in the vicinity of French Polynesia University site, during eight years from 2001 to 2008. In addition, we also include the IPW calculated using Era-Interim reanalyses (ECMWF). The main purpose of this paper is to highlight precision, qualities and limitations of each method available on the Island of Tahiti. During wet periods, the radiosondes vertical profiles of water vapor show an efficient mixing of water vapor between the the boundary layer (below trade winds inversion at Tahiti) and the free troposphere. Thus the rainy event detection allows to better constrain the validity range of a model of the vertical distribution of water vapor, which is based on a pseudo-adiabatic saturated evolution of the temperature.

  10. Study of 1-min rain rate integration statistic in South Korea

    NASA Astrophysics Data System (ADS)

    Shrestha, Sujan; Choi, Dong-You

    2017-03-01

    The design of millimeter wave communication links and the study of propagation impairments at higher frequencies due to a hydrometeor, particularly rain, require the knowledge of 1-min. rainfall rate data. Signal attenuation in space communication results are due to absorption and scattering of radio wave energy. Radio wave attenuation due to rain depends on the relevance of a 1-min. integration time for the rain rate. However, in practice, securing these data over a wide range of areas is difficult. Long term precipitation data are readily available. However, there is a need for a 1-min. rainfall rate in the rain attenuation prediction models for a better estimation of the attenuation. In this paper, we classify and survey the prominent 1-min. rain rate models. Regression analysis was performed for the study of cumulative rainfall data measured experimentally for a decade in nine different regions in South Korea, with 93 different locations, using the experimental 1-min. rainfall accumulation. To visualize the 1-min. rainfall rate applicable for the whole region for 0.01% of the time, we have considered the variation in the rain rate for 40 stations across South Korea. The Kriging interpolation method was used for spatial interpolation of the rain rate values for 0.01% of the time into a regular grid to obtain a highly consistent and predictable rainfall variation. The rain rate exceeded the 1-min. interval that was measured through the rain gauge compared to the rainfall data estimated using the International Telecommunication Union Radio Communication Sector model (ITU-R P.837-6) along with the empirical methods as Segal, Burgueno et al., Chebil and Rahman, logarithmic, exponential and global coefficients, second and third order polynomial fits, and Model 1 for Icheon regions under the regional and average coefficient set. The ITU-R P. 837-6 exhibits a lower relative error percentage of 3.32% and 12.59% in the 5- and 10-min. to 1-min. conversion, whereas the

  11. Frequent Rain Observation From Geostationary Satellite

    NASA Astrophysics Data System (ADS)

    Bizzarri, B.; Gomas Science Team

    The target 3-h observing cycle of GPM will meet requirements from Global NWP and, to a large extent, Regional NWP; and be supportive of VIS/IR-derived rain estimates from geostationary satellites for the purpose of Nowcasting. MW rain observation from geostationary orbit at, say, 15 min intervals, would fully meet Regional NWP requirements and have greatest impact on Nowcasting: but this implies either unprac- tically large antennas or unacceptably coarse resolution. Concepts to overcome this problem have been developed in the US within the study called GEM (Geostationary Microwave Observatory), and now there is in Europe a proposal for a demonstration satellite submitted to ESA as GOMAS (Geostationary Observatory for Microwave Atmospheric Sounding). To overcome the problem of resolution, use of Sub-mm fre- quencies is envisaged: e.g., at 425 GHz, a 10-km resolution at nadir would require a 3-m antenna. The observing principle is based on the use of absorption bands of oxygen (54, 118 and 425 GHz) and of water vapour (183 and 380 GHz). Narrow- bandwidths channels are implemented (for a total of about 40 in the five bands) so as to observe the full profile of temperature and water vapour. Profiles from different bands are differently affected by liquid and ice water of different drop size, and fi- nally by precipitation. Simultaneous retrieval of temperature/humidity profiles, cloud liquid/ice water (total-columns and gross profile) and precipitation rate is in principle possible, and partially demonstrated by several airborne MW/Sub-mm instruments. To transfer this demonstrations in the geostationary orbit, the problem of radiometric sensitivity (additional to that one of the antenna size) has to be solved. With current technology, it is feasible to get sufficient accuracy if scan is limited to about 1/12 of the Earth disk, which is sufficient to abundantly cover Europe, the Mediterranean and Eastern Atlantic. The imaged area can be moved everywhere within the disk

  12. EFFECT OF AN ACID RAIN ENVIRONMENT ON LIMESTONE SURFACES.

    USGS Publications Warehouse

    Mossotti, Victor G.; Lindsay, James R.; Hochella, Michael F.

    1987-01-01

    Salem limestone samples were exposed to weathering for 1 y in several urban and one rural environments. Samples exposed in the rural location were chemically indistinguishable from the freshly quarried limestone, whereas all samples collected from urban exposure sites developed gypsum stains on the ground-facing surfaces where the stones were not washed by precipitation. The gas-solid reaction of SO//2 with calcite was selected for detailed consideration. It appears from the model that under arid conditions, the quantity of stain deposited on an unwashed surface is independent of atmospheric SO//2 concentration once the surface has been saturated with gypsum. Under wet conditions, surface sulfation and weight loss are probably dominated by mechanisms involving wet stone. However, if the rain events are frequent and delimited by periods of dryness, the quantity of gypsum produced by a gas-solid reaction mechanism should correlate with both the frequency of rain events and the atmospheric SO//2 level.

  13. The second-moment climatology of the GATE rain rate data

    NASA Technical Reports Server (NTRS)

    Polyak, Ilya; North, Gerald

    1995-01-01

    The first part of this paper presents the description of the GARP (Global Atmospheric Research Program) Atlantic Tropical Experiment (GATE) 1 rain-rate data and its two-dimensional spectral and correlation characteristics, which has made it possible to accomplish the following: to show the concentration of a significant power along the frequency axis in the spatiotemporal spectra; to detect a diurnal cycle (which has a range of variation of about 3.4-5.4 mm/n) as one of the sources of bias in the rain statistics of satellite data; to study the distinction between the north-south and east-west transport of spatial rain-rate field and character of its anisotropy; to evaluate the scales of the distinction between second-moment estimates associated with ground and satellite samples; and to determine the appropriate spatial and temporal scales of simple linear stochastic models fitted to averaged rain-rate fields. The second part of this paper is devoted to an analysis of the diffusion of the rain rate by establishing a relationship between the parameters of the multivariate autoregressive model and the coefficients of a diffusion equation. This analysis led to the use of rain data to estimate the rain advection velocity as well as other coefficients of the diffusion equation of the corresponding field. The results obtained can be used for comparison with corresponding estimates of other sources of data (satellite, Tropical Oceans Global Atmosphere Coupled Ocean - Atmosphere Response Experiment (TOGA, COARE) or simulated by physical models), for generating multiple samples of any size, for solving the inverse problems of some of the hydrodynamic equations, and in some other areas of rain data analysis and modeling.

  14. The influence of polarization on millimeter wave propagation through rain. [radio signals

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Stutzman, W. L.; Wiley, P. H.; Marshall, R. E.

    1973-01-01

    The measurement and analysis of the depolarization and attenuation that occur when millimeter wave radio signals propagate through rain are described. Progress was made in three major areas: the processing of recorded 1972 data, acquisition and processing of a large amount of 1973 data, and the development of a new theoretical model to predict rain cross polarization and attenuation. Each of these topics is described in detail along with radio frequency system design for cross polarization measurements.

  15. Physical initialization using SSM/I rain rates

    NASA Technical Reports Server (NTRS)

    Krishnamurti, T. N.; Bedi, H. S.; Ingles, Kevin

    1993-01-01

    Following our recent study on physical initialization for tropical prediction using rain rates based on outgoing long-wave radiation, the present study demonstrates a major improvement from the use of microwave radiance-based rain rates. A rain rate algorithm is used on the data from a special sensor microwave instrument (SSM/I). The initialization, as before, uses a reverse surface similarity theory, a reverse cumulus parameterization algorithm, and a bisection method to minimize the difference between satellite-based and the model-based outgoing long-wave radiation. These are invoked within a preforecast Newtonian relaxation phase of the initialization. These tests are carried out with a high-resolution global spectral model. The impact of the initialization on forecast is tested for a complex triple typhoon scenario over the Western Pacific Ocean during September 1987. A major impact from the inclusion of the SSM/I is demonstrated. Also addressed are the spin-up issues related to the typhoon structure and the improved water budget from the physical initialization.

  16. Exploring the nonlinear cloud and rain equation.

    PubMed

    Koren, Ilan; Tziperman, Eli; Feingold, Graham

    2017-01-01

    Marine stratocumulus cloud decks are regarded as the reflectors of the climate system, returning back to space a significant part of the income solar radiation, thus cooling the atmosphere. Such clouds can exist in two stable modes, open and closed cells, for a wide range of environmental conditions. This emergent behavior of the system, and its sensitivity to aerosol and environmental properties, is captured by a set of nonlinear equations. Here, using linear stability analysis, we express the transition from steady to a limit-cycle state analytically, showing how it depends on the model parameters. We show that the control of the droplet concentration (N), the environmental carrying-capacity (H0), and the cloud recovery parameter (τ) can be linked by a single nondimensional parameter (μ=N/(ατH0)), suggesting that for deeper clouds the transition from open (oscillating) to closed (stable fixed point) cells will occur for higher droplet concentration (i.e., higher aerosol loading). The analytical calculations of the possible states, and how they are affected by changes in aerosol and the environmental variables, provide an enhanced understanding of the complex interactions of clouds and rain.

  17. Seminal role of stratiform clouds in large-scale aggregation of tropical rain in boreal summer monsoon intraseasonal oscillations

    NASA Astrophysics Data System (ADS)

    Kumar, Siddharth; Arora, Anika; Chattopadhyay, R.; Hazra, Anupam; Rao, Suryachandra A.; Goswami, B. N.

    2016-04-01

    Modification of the vertical structure of non-adiabatic heating by significant abundance of the stratiform rain in the tropics has been known to influence the large-scale circulation. However, the role of the stratiform rain on the space-time evolution of the observed Boreal summer monsoon intraseasonal oscillations (MISO) has so far been ignored. In the present study, we unravel a feedback mechanism through which the stratiform component of the rain leads to aggregation (organization) of rain on the MISO scale, making it an indispensable component of the MISO evolution dynamics. Using TRMM 3A25 monthly mean data (between 1998 and 2013), the ratio between convective and stratiform rain (RCS) is shown to be strongly related to the total rainfall. Further, composites of rainfall and circulation anomalies corresponding to high (low) values of RCS over the Central India or over the Equatorial Indian Ocean show spatial structures remarkably similar to that associated with the MISOs. Analyzing lead-lag relationship between the convective rain, the stratiform rain and the large scale moisture convergence with respect to peak active (break) spells from daily modern era retrospective-analysis for research and applications data, we unravel that the initial isolated convective elements spawn the stratiform rain which in turn modifies the vertical distribution of heating and leads to stronger large scale moisture convergence thereby producing more convective elements and more stratiform rain ultimately leading to aggregation of rain on the MISO scale. Our finding indicates that large and persisting systematic biases in simulating the summer monsoon rainfall over the Asian monsoon region by climate models are likely to be related to the systematic biases in simulating the MISOs which in turn are related to the serious underestimation of stratiform rain in most climate models.

  18. Seminal role of stratiform clouds in large-scale aggregation of tropical rain in boreal summer monsoon intraseasonal oscillations

    NASA Astrophysics Data System (ADS)

    Kumar, Siddharth; Arora, Anika; Chattopadhyay, R.; Hazra, Anupam; Rao, Suryachandra A.; Goswami, B. N.

    2017-02-01

    Modification of the vertical structure of non-adiabatic heating by significant abundance of the stratiform rain in the tropics has been known to influence the large-scale circulation. However, the role of the stratiform rain on the space-time evolution of the observed Boreal summer monsoon intraseasonal oscillations (MISO) has so far been ignored. In the present study, we unravel a feedback mechanism through which the stratiform component of the rain leads to aggregation (organization) of rain on the MISO scale, making it an indispensable component of the MISO evolution dynamics. Using TRMM 3A25 monthly mean data (between 1998 and 2013), the ratio between convective and stratiform rain (RCS) is shown to be strongly related to the total rainfall. Further, composites of rainfall and circulation anomalies corresponding to high (low) values of RCS over the Central India or over the Equatorial Indian Ocean show spatial structures remarkably similar to that associated with the MISOs. Analyzing lead-lag relationship between the convective rain, the stratiform rain and the large scale moisture convergence with respect to peak active (break) spells from daily modern era retrospective-analysis for research and applications data, we unravel that the initial isolated convective elements spawn the stratiform rain which in turn modifies the vertical distribution of heating and leads to stronger large scale moisture convergence thereby producing more convective elements and more stratiform rain ultimately leading to aggregation of rain on the MISO scale. Our finding indicates that large and persisting systematic biases in simulating the summer monsoon rainfall over the Asian monsoon region by climate models are likely to be related to the systematic biases in simulating the MISOs which in turn are related to the serious underestimation of stratiform rain in most climate models.

  19. Validation of Rain Rate Retrievals for the Airborne Hurricane Imaging Radiometer (HIRAD)

    NASA Technical Reports Server (NTRS)

    Jacob, Maria; Salemirad, Matin; Jones, Linwood; Biswas, Sayak; Cecil, Daniel

    2015-01-01

    NASA's Global Hawk aircraft (AV1)has two microwave sensors: the passive Hurricane Imaging Radiometer (HIRAD), and the active High-altitude Imaging Wind and Rain Airborne Profiler(HIWRAP). Results are presented for a rain measurement validation opportunity that occurred in 2013, when the AV1 flew over a tropical squall-line that was simultaneously observed by the Tampa NEXRAD radar. During this experiment, Global Hawk made 3 passes over the rapidly propagating thunderstorm, while the TAMPA NEXRAD performed volume scans every 5 minutes. In this poster, the three-way inter-comparison of HIRAD Tb (base temperature), HIWRAP dbZ (decibels relative to equivalent reflectivity) and NEXRAD rain rate imagery are presented. Also, observed HIRAD Tbs are compared with theoretical radiative transfer model results using HIWRAP Rain Rates.

  20. Acid rain and its ecological consequences.

    PubMed

    Singh, Anita; Agrawal, Madhoolika

    2008-01-01

    Acidification of rain-water is identified as one of the most serious environmental problems of transboundary nature. Acid rain is mainly a mixture of sulphuric and nitric acids depending upon the relative quantities of oxides of sulphur and nitrogen emissions. Due to the interaction of these acids with other constituents of the atmosphere, protons are released causing increase in the soil acidity Lowering of soil pH mobilizes and leaches away nutrient cations and increases availability of toxic heavy metals. Such changes in the soil chemical characteristics reduce the soil fertility which ultimately causes the negative impact on growth and productivity of forest trees and crop plants. Acidification of water bodies causes large scale negative impact on aquatic organisms including fishes. Acidification has some indirect effects on human health also. Acid rain affects each and every components of ecosystem. Acid rain also damages man-made materials and structures. By reducing the emission of the precursors of acid rain and to some extent by liming, the problem of acidification of terrestrial and aquatic ecosystem has been reduced during last two decades.

  1. Implications for Coronal Heating from Coronal Rain

    NASA Astrophysics Data System (ADS)

    Antolin, P.; Shibata, K.; Carlsson, M.; van der Voort, L. R.; Vissers, G.; Hansteen, V.

    2012-08-01

    Coronal rain is a phenomenon above active regions in which cool plasma condensations fall down from coronal heights. Numerical simulations of loops have shown that such condensations can naturally form in the case of footpoint concentrated heating through the “catastrophic cooling” mechanism. In this work we analize high resolution limb observations in Ca II H and Hα of coronal rain performed by Hinode/SOT and by Crisp of SST and derive statistical properties. We further investigate the link between coronal rain and the coronal heating mechanisms by performing 1.5-D MHD simulations of a loop subject to footpoint heating and to Alfvén waves generated in the photosphere. It is found that if a loop is heated predominantly from Alfvén waves coronal rain is inhibited due to the characteristic uniform heating they produce. Hence coronal rain can point both to the spatial distribution of the heating and to the agent of the heating itself, thus acting as a marker for coronal heating mechanisms.

  2. Rain-induced spring wheat harvest losses

    NASA Technical Reports Server (NTRS)

    Bauer, A.; Black, A. L. (Principal Investigator)

    1983-01-01

    When rain or a combination of rain and high humidity delay wheat harvest, losses can occur in grain yield and/or grain quality. Yield losses can result from shattering, from reduction in test weight, and in the case of windrowed grain, from rooting of sprouting grain at the soil: windrow contact. Losses in grain quality can result from reduction in test weight and from sprouting. Sprouting causes a degradation of grain proteins and starches, hence flour quality is reduced, and the grain price deteriorates to the value of feed grain. Although losses in grain yield and quality are rain-induced, these losses do not necessarily occur because a standing or windrowed crop is wetted by rain. Spike water concentration in hard red spring wheat must be increased to about 45-49% before sprouting is initiated in grain that has overcome dormancy. The time required to overcome this dormancy after the cultivar has dried to 12 to 14% water concentration differs with hard red spring cultivars. The effect of rain on threshing-ready standing and windrowed hard red spring wheat grain yeild and quality was evaluated. A goal was to develop the capability to forecast the extent of expected loss of grain yield and quality from specific climatic events that delay threshing.

  3. A rain splash transport equation assimilating field and laboratory measurements

    USGS Publications Warehouse

    Dunne, T.; Malmon, D.V.; Mudd, S.M.

    2010-01-01

    Process-based models of hillslope evolution require transport equations relating sediment flux to its major controls. An equation for rain splash transport in the absence of overland flow was constructed by modifying an approach developed by Reeve (1982) and parameterizing it with measurements from single-drop laboratory experiments and simulated rainfall on a grassland in East Africa. The equation relates rain splash to hillslope gradient, the median raindrop diameter of a storm, and ground cover density; the effect of soil texture on detachability can be incorporated from other published results. The spatial and temporal applicability of such an equation for rain splash transport in the absence of overland flow on uncultivated hillslopes can be estimated from hydrological calculations. The predicted transport is lower than landscape-averaged geologic erosion rates from Kenya but is large enough to modify short, slowly eroding natural hillslopes as well as microtopographic interrill surfaces between which overland flow transports the mobilized sediment. Copyright 2010 by the American Geophysical Union. Copyright 2010 by the American Geophysical Union.

  4. Optimal Scales for Comparing Satellite and Rain-Gauge Rainfall Estimates for Verification Purposes

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Kundu, Prasun K.

    1999-01-01

    In spite of all their problems, rain gauges measure rainfall in such a direct way when compared with other methods of estimating rainfall that comparing their totals to satellite estimates remains an essential tool in the validation of satellite products. Some disagreement between averages of satellite data and rain-gauge data is expected because of the very different sampling patterns of the two systems--the satellite provides only occasional snapshots of large areas, whereas rain gauges provide continuous measurements over very small areas. The comparison of the two requires that some quantitative measure be supplied for the amount of disagreement that can be tolerated due to the differences in sampling. As part of an effort to determine the sampling error of satellite averages, a space-time model for rainfall statistics was developed and its parameters fit to radar data from a field experiment conducted near the Inter-Tropical Convergence Zone (ITCZ) in the eastern Atlantic (GATE). Although the model was intended to represent the statistics of relatively large scale fluctuations of rain, it is surprisingly consistent with the very different scales on which rain gauges observe. It can therefore be used to study some of the issues involved with comparing rain-gauge averages to satellite averages. Its implications for the best time and space scales for comparing the two will be discussed.

  5. On Study of Air/Space-borne Dual-Wavelength Radar for Estimates of Rain Profiles

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert

    2004-01-01

    In this study, a framework is discussed to apply air/space-borne dual-wavelength radar for the estimation of characteristic parameters of hydrometeors. The focus of our study is on the Global Precipitation Measurements (GPM) precipitation radar, a dual-wavelength radar that operates at Ku (13.8 GHz) and Ka (35 GHz) bands. As the droplet size distributions (DSD) of rain are expressed as the Gamma function, a procedure is described to derive the median volume diameter (D(sub 0)) and particle number concentration (N(sub T)) of rain. The correspondences of an important quantity of dual-wavelength radar, defined as deferential frequency ratio (DFR), to the D(sub 0) in the melting region are given as a function of the distance from the 0 C isotherm. A self-consistent iterative algorithm that shows a promising to account for rain attenuation of radar and infer the DSD without use of surface reference technique (SRT) is examined by applying it to the apparent radar reflectivity profiles simulated from the DSD model and then comparing the estimates with the model (true) results. For light to moderate rain the self-consistent rain profiling approach converges to unique and correct solutions only if the same shape factors of Gamma functions are used both to generate and retrieve the rain profiles, but does not converges to the true solutions if the DSD form is not chosen correctly. To further examine the dual-wavelength techniques, the self-consistent algorithm, along with forward and backward rain profiling algorithms, is then applied to the measurements taken from the 2nd generation Precipitation Radar (PR-2) built by Jet Propulsion Laboratory. It is found that rain profiles estimated from the forward and backward approaches are not sensitive to shape factor of DSD Gamma distribution, but the self-consistent method is.

  6. Modeling a Rain-Induced Mixed Layer

    DTIC Science & Technology

    1990-06-01

    te -)-A-- e e -2)- . (7) ’&Z AZ Az D Using the exponential relations with trigonometry , equation (7) becomes, Ok n) 3 (I- cos2ikAz)+ D (1- cos ikAz...completely unknown because there are no prior studies which predict what portion of total energy may go into subsurface mixing. The biggest obstacle

  7. A novel rain removal technology based on video image

    NASA Astrophysics Data System (ADS)

    Liu, Shuo; Piao, Yan

    2016-11-01

    Due to the effect of bad weather conditions, it often conducts visual distortions on images for outdoor vision systems. Rain is one specific example of bad weather. Generally, rain streak is small and falls at high velocity. Traditional rain removal methods often cause blued visual effect. In addition, there is high time complexity. Moreover, some rain streaks are still in the de-rained image. Based on the characteristics of rain streak, a novel rain removal technology is proposed. The proposed method is not only removing the rain streak effectively, but also retaining much detail information. The experiments show that the proposed method outperform traditional rain removal methods. It can be widely used in intelligent traffic, civilian surveillance and national security so on.

  8. Canada issues booklet describing acid rain

    NASA Astrophysics Data System (ADS)

    A booklet recently released by Environment Canada describes acid rain in terms easily understood by the general public. Although Acid Rain — The Facts tends somewhat to give the Canadian side of this intercountry controversial subject, it nevertheless presents some very interesting, simple statistics of interest to people in either the U.S. or Canada. Copies of the booklet can be obtained from Inquiry Environment Canada, Ottawa, Ontario K1A OH3, Canada, tel. 613-997-2800.The booklet points out that acid rain is caused by emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx). Once released into the atmosphere, these substances can be carried long distances by prevailing winds and return to Earth as acidic rain, snow, fog, or dust. The main sources of SO2 emissions in North America are coal-fired power generating stations and nonferrous ore smelters. The main sources of NOx emissions are vehicles and fuel combustion. From economical and environmental viewpoints, Canada believes acid rain is one of the most serious problems presently facing the country: increasing the acidity of more than 20% of Canada's 300,000 lakes to the point that aquatic life is depleted and acidity of soil water and shallow groundwater is increasing, causing decline in forest growth and water fowl populations, and eating away at buildings and monuments. Acid rain is endangering fisheries, tourism, agriculture, and forest resources in an area of 2.6 million km2 (one million square miles) of eastern Canada, about 8% of Canada's gross national product.

  9. Scanning rain gauge based on photo electricity

    NASA Astrophysics Data System (ADS)

    Huang, Fei-long; Li, Yuan-hong

    2008-03-01

    A non-contact rain gauge with photo electricity technology is introduced in this paper. Dimensional distribution of rain inside a traditional rain gauge does not need to be changed, and the rainwater falls freely to the ground, so this new rain gauge doesn't need to be cleared as a traditional rain gauge does frequently. And then a capacitor is used as a switch that would drive LED light to scan and drive photo electricity inducing element Charge Coupled Device (CCD) to detect when it is induced by the falling drips. Light through a convex lens would scan the drips and project them on CCD across. Electrical signal is produced when CCD detects the shadow after another convex lens. The drips whose diameter is 0.3 millimeter can be distinguished and so as smaller drips of 0.1 millimeter if high-resolution CCD is used. After an amplifier the electrical signal would be transformed into digital signal and would be used to calculate the volume of rain. The Central Processing Unit on main control board gives commands to scanning trigger and controls interrupts from process of data acquisition and calculation. The non-contact photo electricity measurement can detect raindrops of different size. Parallel light projects every raindrop in space on CCD and tells its diameter exactly. So it gives satisfying precision and other useful data such as spectrum of raindrops. Further more, velocity of raindrop would be acquired according to its size. The system needs low cost with universal CCD and Single Chip Micyoco (SCM), and it is worth advocating.

  10. Rain in the U.S. Midwest

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The powerful storms that moved across the U.S. Midwest during the first week of May 2007 brought wind, hail, tornadoes, and drenching rain. This image shows rainfall totals over parts of Oklahoma, Kansas, and Nebraska between May 1 and May 8, based in part on measurements made by the Tropical Rainfall Measuring Mission (TRMM) satellite. More than 400 millimeters (15.7 inches) of rain fell over some regions, corresponding with locations where the National Weather Service reported severe weather. A wide swath of red and orange (between 240 and 400 millimeters of rain) arcs in a clockwise direction from western Oklahoma, through central Kansas, and into southeastern Nebraska. The reddish-orange bull's-eye over southeastern Louisiana is evidence of the torrential rains that pounded visitors to the annual New Orleans Jazz Festival. South-central Texas' Edward Plateau was soaked with more than 240 millimeters of rain during the period, as well. From May 4 to May 8, the National Weather Service received approximately 683 reports of severe weather, 140 of which were reports of tornadoes, including the massive F5 tornado that devastated the city of Greensburg, Kansas. Beyond the damaging winds and tornadoes, the torrential rain triggered extensive flooding throughout the Central Plains. On the evening of May 7, flood warnings were in effect from South Dakota to southern Texas, and by May 8, the Hydrologic Information Center reported moderate to major flooding at 53 stream gauge sites in South Dakota, Iowa, Kansas, Nebraska, Missouri, and Arkansas. The floods could be as severe as the 1993 flood, one of the costliest floods in U.S. history, reported the Associated Press.

  11. Combined effects of simulated acid rain and lanthanum chloride on chloroplast structure and functional elements in rice.

    PubMed

    Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2016-05-01

    Acid rain and rare earth element (REE) pollution exist simultaneously in many agricultural regions. However, how REE pollution and acid rain affect plant growth in combination remains largely unknown. In this study, the combined effects of simulated acid rain and lanthanum chloride (LaCl3) on chloroplast morphology, chloroplast ultrastructure, functional element contents, chlorophyll content, and the net photosynthetic rate (P n) in rice (Oryza sativa) were investigated by simulating acid rain and rare earth pollution. Under the combined treatment of simulated acid rain at pH 4.5 and 0.08 mM LaCl3, the chloroplast membrane was smooth, proteins on this membrane were uniform, chloroplast structure was integrated, and the thylakoids were orderly arranged, and simulated acid rain and LaCl3 exhibited a mild antagonistic effect; the Mg, Ca, Mn contents, the chlorophyll content, and the P n increased under this combined treatment, with a synergistic effect of simulated acid rain and LaCl3. Under other combined treatments of simulated acid rain and LaCl3, the chloroplast membrane surface was uneven, a clear "hole" was observed on the surface of chloroplasts, and the thylakoids were dissolved and loose; and the P n and contents of functional elements (P, Mg, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo) and chlorophyll decreased. Under these combined treatments, simulated acid rain and LaCl3 exhibited a synergistic effect. Based on the above results, a model of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis was established in order to reveal the combined effects on plant photosynthesis, especially on the photosynthetic organelle-chloroplast. Our results would provide some references for further understanding the mechanism of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis.

  12. Long-term effects of the rain exposure shortly after the atomic bombings in Hiroshima and Nagasaki.

    PubMed

    Sakata, Ritsu; Grant, Eric J; Furukawa, Kyoji; Misumi, Munechika; Cullings, Harry; Ozasa, Kotaro; Shore, Roy E

    2014-12-01

    The "black rain" that fell after the atomic bombings of Hiroshima and Nagasaki has been generally believed to contain radioactive materials. During 1949-1961 the Atomic Bomb Casualty Commission conducted surveys that included a query about exposure to the rain that fell a short time after the bombings. This article presents the first report of those data in relation to possible adverse health outcomes. This study looked at Life Span Study subjects who were in either city at the time of bombing and had an estimated direct radiation dose from the bombs (n = 86,609). The mortality data from 1950-2005 and cancer incidence data from 1958-2005 were used. Excess relative risks (ERRs) of subjects who were exposed to rain compared to those who reported no rain exposure were calculated using a Poisson regression model. In Hiroshima 11,661 subjects (20%) reported that they were exposed to rain, while in Nagasaki only 733 subjects (2.6%) reported rain exposure. To avoid outcome dependent biases (i.e., recall of exposure after a health outcome has already occurred), the primary analyses were based on events that occurred during 1962-2005. No significant risks due to rain exposure were observed for death due to all causes, all solid cancer or leukemia in Hiroshima. In Nagasaki there was no significantly elevated rain exposure-associated risks for 1962-2005, however, for 1950-2005 there was a weak association for all-cause mortality (ERR = 0.08; 95% confidence interval 0.00006, 0.17; P = 0.05). For incidence of solid cancer and leukemia, no significantly elevated rain exposure risks were observed in either city. These results failed to show deleterious health effects from rain exposure. While these data represent the most extensive set of systematically collected data on rain exposure of the atomic bomb survivors, they are limited by substantial uncertainties regarding exposures and missing individual data, so cautious interpretation is advised.

  13. Acid rain and electric utilities 2

    SciTech Connect

    1997-12-31

    This proceedings contains more than 100 technical presentations dealing with a variety of topics concerning the Title IV acid rain provisions of the Clean Air Act Amendments of 1990. Some of the major topics addressed include: emerging environmental issues impacting electric utilities (proposed revisions to the ozone and particulate matter NAAQS), acid rain program overview, continuous emissions monitoring rule revisions, global climate change and CO{sub 2}, emissions data management, Clean Air Power Initiative and regional issues, compliance/designated representative, flow monitoring, emissions control technology, allowance and trading, emission reductions, NO{sub x} control issues, hazardous air pollutants, and CEMS advances.

  14. Acid rain: Engineering solutions, regulatory aspects

    SciTech Connect

    Schwieger, R.G.; Elliott, T.C.

    1985-01-01

    Keeping up with efforts to control acid rain, this reference presents current scientific aspects associated with the problem of political and legislative concerns and ideas for developing effective mitigation programs at reasonable cost. The contributors are the authorities in attendance at the Second International Conference on Acid Rain - and this work represents the first time engineers and managers with firsthand knowledge of systems and equipment to reduce SO/sub 2/ and NO/sub x/ emissions gathered in one place. Throughout the book, some 200 tables, charts, diagrams, and photographs augment the textual material.

  15. Multicriteria design of rain gauge networks for flash flood prediction in semiarid catchments with complex terrain

    NASA Astrophysics Data System (ADS)

    Volkmann, Till H. M.; Lyon, Steve W.; Gupta, Hoshin V.; Troch, Peter A.

    2010-11-01

    Despite the availability of weather radar data at high spatial (1 km2) and temporal (5-15 min) resolution, ground-based rain gauges continue to be necessary for accurate estimation of storm rainfall input to catchments during flash flood events, especially in mountainous catchments. Given economical considerations, a long-standing problem in catchment hydrology is to establish optimal placement of a small number of rain gauges to acquire data on both rainfall depth and spatiotemporal variability of intensity during extreme storm events. Using weather radar observations and a dense network of 40 tipping bucket rain gauges, this study examines whether it is possible to determine a reliable "best" set of rain gauge locations for the Sabino Canyon catchment near Tucson, Arizona, USA, given its complex topography and dominant storm track pattern. High-quality rainfall data are used to evaluate all possible configurations of a "practical" network having from one to four rain gauges. A multicriteria design strategy is used to guide rain gauge placement, by simultaneously minimizing the residual percent bias and maximizing the coefficient of correlation between the estimated and true mean areal rainfall and minimizing the normalized spatial mean squared error between the estimated and true spatiotemporal rainfall distribution. The performance of the optimized rain gauge network was then compared against randomly designed network ensembles by evaluating the quality of streamflows predicted using the Kinematic Runoff and Erosion (KINEROS2) event-based rainfall-runoff model. Our results indicate that the multicriteria strategy provided a robust design by which a sparse but accurate network of rain gauges could be implemented for semiarid basins such as the one studied.

  16. How much water can pollution aerosols hold in the cloud by suppressing warm rain?

    NASA Astrophysics Data System (ADS)

    Rosenfeld, D.

    2009-12-01

    Vertical profiles of aerosols, cloud drop size distribution and hydrometeors were measured by cloud physics airplanes in a wide range of locations in the world and a wide range of aerosol properties. This includes tropical clouds in the Amazon and Indian Monsoon, severe convective clouds in Argentina and the USA, and winter clouds in California and Israel. The aerosol conditions span from pristine maritime to heavy air pollution and smoke from forest fires, and includes large aerosols such as desert dust and sea spray. It is found that heavy air pollution that is dominated by small cloud condensation nuclei (CCN) can suppress the warm rain processes in warm base clouds (cloud base temperature >20C) up to heights of more than 5 km above cloud base, which is well above the freezing level. The warm rain is formed as supercooled rain that freezes and gets rimed into graupel. Such clouds have intense electrical activity. In microphysically highly continental vigorous convective clouds with cold base of 12C, warm rain is also delayed to 5 km above base. The onset of warm rain in these clouds occur at temperatures close to the homogeneous ice nucleation isotherm of -35C and colder. The resultant drizzle forms the embryos of ice hydrometeors. Giant CCN from dust and sea salt initiate the rain faster than would have been expected based on the concentration of small CCN. A relation between CCN concentration and cloud depth for onset of warm rain can be formulated and applied to cloud parameterization in models that do not calculate explicitly the rain forming processes in clouds.

  17. Automated rain rate estimates using the Ka-band ARM Zenith Radar (KAZR)

    NASA Astrophysics Data System (ADS)

    Chandra, A.; Zhang, C.; Kollias, P.; Matrosov, S.; Szyrmer, W.

    2014-02-01

    The use of millimeter wavelength radars for probing precipitation has recently gained interest. However, estimation of precipitation variables is not straightforward due to strong attenuation, radar receiver saturation, antenna wet radome effects and natural microphysical variability. Here, an automated algorithm is developed for routinely retrieving rain rates from profiling Ka-band (35-GHz) ARM zenith radars (KAZR). A 1-D simple, steady state microphysical model is used to estimate the impact of microphysical processes and attenuation on the profiles of the radar observables at 35-GHz and thus provide criteria for identifying when attenuation or microphysical processes dominate KAZR observations. KAZR observations are also screened for saturation and wet radome effects. The proposed algorithm is implemented in two steps: high rain rates are retrieved by using the amount of attenuation in rain layers, while lower rain rates by the Ze-R (reflectivity-rain rate) relation is implemented. Observations collected by the KAZR, disdrometer and scanning weather radars during the DYNAMO/AMIE field campaign at Gan Island of the tropical Indian Ocean are used to validate the proposed approach. The results indicate that the proposed algorithm can be used to derive robust statistics of rain rates in the tropics from KAZR observations.

  18. Forecasting of monsoon heavy rains: challenges in NWP

    NASA Astrophysics Data System (ADS)

    Sharma, Kuldeep; Ashrit, Raghavendra; Iyengar, Gopal; Bhatla, R.; Rajagopal, E. N.

    2016-05-01

    Last decade has seen a tremendous improvement in the forecasting skill of numerical weather prediction (NWP) models. This is attributed to increased sophistication in NWP models, which resolve complex physical processes, advanced data assimilation, increased grid resolution and satellite observations. However, prediction of heavy rains is still a challenge since the models exhibit large error in amounts as well as spatial and temporal distribution. Two state-of-art NWP models have been investigated over the Indian monsoon region to assess their ability in predicting the heavy rainfall events. The unified model operational at National Center for Medium Range Weather Forecasting (NCUM) and the unified model operational at the Australian Bureau of Meteorology (Australian Community Climate and Earth-System Simulator -- Global (ACCESS-G)) are used in this study. The recent (JJAS 2015) Indian monsoon season witnessed 6 depressions and 2 cyclonic storms which resulted in heavy rains and flooding. The CRA method of verification allows the decomposition of forecast errors in terms of error in the rainfall volume, pattern and location. The case by case study using CRA technique shows that contribution to the rainfall errors come from pattern and displacement is large while contribution due to error in predicted rainfall volume is least.

  19. Effects of rain damage on wilting forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most common problems faced by hay or silage producers is how to manage production schedules around unfavorable weather. Inevitably, some wilting forage crops are damaged by unexpected rainfall events each year, and producers often inquire about the effects of unexpected rain damage, and w...

  20. Acid Rain Program CEM audit program

    SciTech Connect

    Nguyen, K.O.T.; Alexander, T.H.; Dupree, J.C.

    1997-12-31

    This presentation will give an overview of the Acid Rain Program CEM Audit Program: electronic and field audits. The presentation will include the reasons for audits, field audit types and levels the steps used in develop in the audit program and the audit procedures.

  1. Acid Rain: A Description of Bilingual Friesland.

    ERIC Educational Resources Information Center

    Zondag, Koen

    1984-01-01

    Using acid rain as a metaphor, discusses the status of the Frisian language and culture as one which, though apparently thriving, is really threatened. Examines the sources of this threat, i.e., the education system, the church, mass communication and transportation, and the demise of the Frisian village community. (SED)

  2. Air quality monitor and acid rain networks

    NASA Technical Reports Server (NTRS)

    Rudolph, H.

    1980-01-01

    The air quality monitor program which consists of two permanent air monitor stations (PAMS's) and four mobile shuttle pollutant air monitor stations (SPAMS's) is evaluated. The PAMS measures SO sub X, NO sub X particulates, CO, O3, and nonmethane hydrocarbons. The SPAMS measures O3, SO2, HCl, and particulates. The collection and analysis of data in the rain monitor program are discussed.

  3. Acid Rain Materials for Classroom Use.

    ERIC Educational Resources Information Center

    Factor, Lance; Kooser, Robert G.

    This booklet contains three separate papers suitable for use in an advanced high school or college chemistry course. The first paper provides background information on acids and bases. The second paper provides additional background information, focusing on certain aspects of atmospheric chemistry as it relates to the acid rain problem. An attempt…

  4. TECHNOLOGICAL OPTIONS FOR ACID RAIN CONTROL

    EPA Science Inventory

    The paper discusses technological options for acid rain control. Compliance with Title IV of the Clean Air Act Amendments of 1990 will require careful scrutiny of a number of issues before selecting control options to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions...

  5. Acid Rain: A Student's First Sourcebook.

    ERIC Educational Resources Information Center

    Kyle, Beth Ann; And Others

    The purpose of this guide is to help students better understand the science, citizen action, and research issues that are part of the acid rain problem. The guide is designed for students in grades 4-8 and their teachers. Following an introduction, the first seven sections are informative in nature. They include: (1) "Observations about Acidity";…

  6. Acid Rain. Teacher's Guide. LHS GEMS.

    ERIC Educational Resources Information Center

    Hocking, Colin; Barber, Jacqueline; Coonrod, Jan

    This teacher's guide presents a unit on acid rain and introduces hands-on activities for sixth through eighth grade students. In each unit, students act as real scientists and gather evidence by using science process skills such as observing, measuring and recording data, classifying, role playing, problem solving, critical thinking, synthesizing…

  7. Acid Rain: Resource Materials for Schools.

    ERIC Educational Resources Information Center

    American Biology Teacher, 1983

    1983-01-01

    Provides listings of acid rain resource material groups under: (1) printed materials (pamphlets, books, articles); (2) audiovisuals (slide/tape presentations, tape, video-cassette); (3) miscellaneous (buttons, pocket lab, umbrella); (4) transparencies; (5) bibliographies; and (6) curriculum materials. Sources and prices (when applicable) are…

  8. Rain compensation algorithm for ACTS mobile terminal

    NASA Astrophysics Data System (ADS)

    Levitt, Barry K.

    1992-02-01

    The initial advanced communication technology satellite (ACTS) mobile terminal (AMT) demonstrations will involve two-way communications between the high-bit-rate link evaluation terminal (HBR-LET), which is a fixed terminal (FT), and a van-housed mobile terminal (MT). The HBR-LET has the capability of adjusting its transmitted uplink power over an approximately 10-dB range to compensate for forward uplink rain attenuation. However, because of size and weight limitations, the MT cannot use power control as a rain compensation technique. Consequently, the AMT rain compensation algorithm (RCA) is based on a formula for varying the transmitted data rate in either direction to maintain link performance within acceptable limits. The objective of the AMT RCA is to ensure reliable operation in both the forward and return directions despite the possibility of uplink or downlink fading due to rain events in the vicinity of the FT or MT. In particular, the RCA must maintain at least a 3-dB link margin at the highest possible transmission rate (AMT can operate at 9.6, 4.8, or 2.4 kb/s) permitted by the prevailing channel conditions. The 3-dB minimum link margin is a system design safety factor to accommodate conceivable implementation losses.

  9. Promoting nitrate removal in rain gardens

    EPA Science Inventory

    Rain gardens are vegetated surface depressions, often located at low points in landscapes, designed to receive stormwater runoff from roads, roofs, and parking lots. The gardens’ sandy soils allow stormwater to drain quickly to the native soils below and eventually to groundwate...

  10. Rain Barrels: A Catalyst for Change?

    ERIC Educational Resources Information Center

    Bakacs, Michele E.; Haberland, Mike; Mangiafico, Salvatore S.; Winquist, Aileen; Obropta, Christopher C.; Boyajian, Amy; Mellor, Sara

    2013-01-01

    Over the past 4 years, rain barrel programming for residents has been implemented in both Northern Virginia and New Jersey as a method for educating the public about stormwater management and water conservation. Program participants demonstrated a significant increase in knowledge of water resource issues. Follow-up surveys showed 58% of New…

  11. GPM Rain Rates in Tropical Cyclone Pam

    NASA Video Gallery

    NASA-JAXA's GPM Satellite Close-up of Cyclone Pam's Rainfall NASA-JAXA's GPM core satellite captured rain rates in Tropical Cyclone Pam at 03:51 UTC (2:51 p.m. local time) on March 14, 2015. Heavie...

  12. Comparison of 1-min rain rate derived from TRMM satellite data and raingauge data for microwave applications in Nigeria

    NASA Astrophysics Data System (ADS)

    Ojo, J. S.; Omotosho, T. V.

    2013-09-01

    A comparative statistical study of derived 1-min rain rate using data obtained from Tropical Rainfall Measuring Mission (TRMM) satellite (3A12 V6 and 3B43V6) and raingauge measurements are presented. 30-years data of rainfall intensities obtained from the Nigerian Meteorological Agency rain-gauge network and 9-years rainfall data obtained from TRMM satellite are used. Cumulative distributions of rain rate were obtained using a combination of an improved version of the Moupfouma-Martin model for rain rate prediction in the tropical regions. Variations of rain rate of different integration time are compared for 28 stations across Nigeria. The Kriging interpolation method was used for spatial interpolation of rain accumulation values into a regular grid in order to obtain a highly consistent and predictable inter-gauge rainfall variation. Noticeable differences between rain rate estimated from rain-gauge and TRMM data were found to be a function of period and location. From quantitative comparison over each of the region, there are reasonably positive correlations between the two sets of data for different percentages of time with correlation coefficient varying from 0.84 to 0.99 at 99.99% availability of time. Comparison with ITU-R 837-5 shows that, ITU model underestimates rain rate as high as 51% from the mean value depending on the percentages of at which time rain rate is exceeded. The overall result shows that the gauge data perform better than TRMM data in most of the sites located in the SW, SE, SS, MB and NE regions, while TRMM data provided better results for sites in the NW region from the statistical perspective with the lower RMS values.

  13. Evaluating of the rain effect on tropical rainfall mapping mission precipitation radar backscatter at low incidence angles

    NASA Astrophysics Data System (ADS)

    Ren, Lin; Yang, Jingsong; Zheng, Gang; Wang, Juan

    2016-10-01

    This paper evaluates the rain effects on Ku-band radar backscatter at low incidence angles. The data used consisted of the sea surface backscatter and averaged rain rates from Tropical Rainfall Mapping Mission precipitation radar (TRMM PR) measurements and the collocated 10-m height numerical prediction wind speeds from the European Centre for Medium-Range Weather Forecasts (ECMWF). The wind-induced backscatter was estimated by the Ku-band low incidence backscatter model (KuLMOD) and possible bias due to different wind speed inputs was considered. The rain effect was analysed by comparing the TRMM PR-measured surface backscatter for the rain-affected sea surface with the collocated wind-induced backscatter. We found that the surface backscatter decreases with increases in the averaged rain rate. The rain-induced backscatter was clearly dependent of the wind speed and was slightly dependent of the incidence angle. Results show that it is necessary to develop a wind and rain backscatter model instead of single wind backscatter model.

  14. 40 CFR 76.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false General Acid Rain Program provisions. 76.3 Section 76.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.3 General Acid Rain Program...

  15. 40 CFR 76.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false General Acid Rain Program provisions. 76.3 Section 76.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.3 General Acid Rain Program...

  16. 40 CFR 76.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false General Acid Rain Program provisions. 76.3 Section 76.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.3 General Acid Rain Program...

  17. 40 CFR 76.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false General Acid Rain Program provisions. 76.3 Section 76.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.3 General Acid Rain Program...

  18. 40 CFR 76.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false General Acid Rain Program provisions. 76.3 Section 76.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.3 General Acid Rain Program...

  19. Effects of acid rain on crops and trees

    SciTech Connect

    Cowling, E.B.; Dochinger, L.S.

    1984-01-01

    A general treatment of the subject of acid rain and its effets are discussed along with sources of acid rain and its near-term (the last couple of decades). The effects of acid rain on terrestrial ecosystems are treated in some detail. Some treatment is given of the ecosystem-level effects of acid precipitation.

  20. 14 CFR 33.78 - Rain and hail ingestion.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Rain and hail ingestion. 33.78 Section 33... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.78 Rain and... rain and hail, as defined in appendix B to this part. Acceptable engine operation precludes...

  1. 14 CFR 33.78 - Rain and hail ingestion.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rain and hail ingestion. 33.78 Section 33... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.78 Rain and... rain and hail, as defined in appendix B to this part. Acceptable engine operation precludes...

  2. 14 CFR 33.78 - Rain and hail ingestion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Rain and hail ingestion. 33.78 Section 33... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.78 Rain and... rain and hail, as defined in appendix B to this part. Acceptable engine operation precludes...

  3. 14 CFR 33.78 - Rain and hail ingestion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Rain and hail ingestion. 33.78 Section 33... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.78 Rain and... rain and hail, as defined in appendix B to this part. Acceptable engine operation precludes...

  4. 14 CFR 33.78 - Rain and hail ingestion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Rain and hail ingestion. 33.78 Section 33... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.78 Rain and... rain and hail, as defined in appendix B to this part. Acceptable engine operation precludes...

  5. The Effects of Rain Garden Size on Performance

    EPA Science Inventory

    The presentation discusses the effect of rain garden size on the hydrologic and pollutant removal performance of rain garden systems. The slides will summarize data from both the full-scale rain garden project associated with the permeable pavement parking lot as well as the pilo...

  6. Using NEXRAD and Rain Gauge Precipitation Data for Hydrologic Calibration of SWAT in a Northeastern Watershed

    SciTech Connect

    A. M. Sexton,; A. M. Sadeghi,; X. Zhang,; R. Srinivasan,; A. Shirmohammadi,

    2010-01-01

    The value of watershed-scale, hydrologic and water quality models to ecosystem management is increasingly evident as more programs adopt these tools to evaluate the effectiveness of different management scenarios and their impact on the environment. Quality of precipitation data is critical for appropriate application of watershed models. In small watersheds, where no dense rain gauge network is available, modelers are faced with a dilemma to choose between different data sets. In this study, we used the German Branch (GB) watershed (~50 km2), which is included in the USDA Conservation Effects Assessment Project (CEAP), to examine the implications of using surface rain gauge and next-generation radar (NEXRAD) precipitation data sets on the performance of the Soil and Water Assessment Tool (SWAT). The GB watershed is located in the Coastal Plain of Maryland on the eastern shore of Chesapeake Bay. Stream flow estimation results using surface rain gauge data seem to indicate the importance of using rain gauges within the same direction as the storm pattern with respect to the watershed. In the absence of a spatially representative network of rain gauges within the watershed, NEXRAD data produced good estimates of stream flow at the outlet of the watershed. Three NEXRAD datasets, including (1)*non-corrected (NC), (2) bias-corrected (BC), and (3) inverse distance weighted (IDW) corrected NEXRAD data, were produced. Nash-Sutcliffe efficiency coefficients for daily stream flow simulation using these three NEXRAD data ranged from 0.46 to 0.58 during calibration and from 0.68 to 0.76 during validation. Overall, correcting NEXRAD with rain gauge data is promising to produce better hydrologic modeling results. Given the multiple precipitation datasets and corresponding simulations, we explored the combination of the multiple simulations using Bayesian model averaging.

  7. State acid rain permitting programs: A report from EPA

    SciTech Connect

    Miller, R.L.

    1995-12-31

    States and EPA are laying the groundwork for state acid rain permitting in Phase 2 of the Acid Rain Program. Early indications suggest a high degree of state compliance with the acid rain permitting requirements of the Acid Rain Program. Phase 2 acid rain permitting forms have been revised and are available on EPA`s Technology Transfer Network. EPA has developed a policy and rationale concerning submission of Phase 2 permit applications, as well as suggested state timing and methodology regarding adoption of 40 CFR Part 76, the NO{sub x} regulation.

  8. The Acid Rain Program: Monitoring the future

    SciTech Connect

    Bloomer, B.J.

    1995-12-31

    This paper presents a summary of the development of the Acid Rain Program`s approach to Continuous Emissions Monitoring Systems (CEMS) and their use in the market based pollution control program of Title IV of the Clean Air Act Amendments of 1990. The roles of the regulatory agencies are discussed and projections are put forward as to how the roles will evolve over time. In addition a discussion of the activities the regulated community is expected to focus on is presented. Finally, a discussion occurs about the requirements that new technologies and instrument providers and purchasers should keep in mind about the Acid Rain Program`s monitoring requirements as they attempt to bring new products into this market.

  9. Climatology tuned reflectivity-rain rate relations

    NASA Technical Reports Server (NTRS)

    Short, David A.; Rosenfeld, Daniel; Atlas, David

    1989-01-01

    The climatologically-tuned relationships between reflectivity, Z, and rain rate, R, are examined. A method is presented which selects the Z-R relation that assures that the values of R are weighted according to their climatological frequency of occurrence. The method is an extension of the approach suggested by Calheiros and Zawadski (1987). Also, consideration is given to the method of optimizing Z-R relations by matching hourly gage and radar-deduced rain amounts proposed by Smith et al. (1975). These two methods are described and applied to data from Germany and from the GARP Atlantic Tropical Experiment. The differences in the Z-R relations obtained using the two approaches are discussed.

  10. Fraud in the acid rain debate

    SciTech Connect

    Bagge, C.

    1984-06-01

    Electric utility executives, according to the author, and millions of other Americans are the victims of a gigantic fraud being carried on in the name of controlling acid rain. This fraud, states the author, involves the distorted, dire image of acidity in nature being created by environmental groups, politicians and others - to gain public sympathy for their legislative goals. The alleged fraud involves the very nature of the legislation being promoted as a low-cost cure for acid rain. On the basis of scientific evidence to date there is no assurance it will reduce acidity by any appreciable amount, but on the other hand it most certainly will cost users of electricity hundreds of billions of dollars in new costs. What has already happened to the nuclear industry is also meant for coal.

  11. Isotopic equilibrium between precipitation and water vapor: evidence from continental rains in central Kenya

    NASA Astrophysics Data System (ADS)

    Soderberg, K.; Gerlein, C.; Kemeny, P. C.; Caylor, K. K.

    2013-12-01

    An accurate understanding of the relationships between the isotopic composition of liquid water and that of water vapor in the environment can help describe hydrologic processes across many scales. One such relationship is the isotopic equilibrium between falling raindrops and the surrounding vapor. The degree of equilibration is used to model the isotopic composition of precipitation in isotope-enable general circulation models and land-atmosphere exchange models. Although this equilibrium has been a topic of isotope hydrology research for more than four decades, few studies have included vapor measurements to validate modeling efforts. Recent advances in laser technology have allowed for in situ vapor measurements at high temporal resolution (e.g., >1 Hz). Here we present concomitant rain and vapor measurements for a series of 17 rain events during the 'Continental' rainy season (June through August) at Mpala Research Center in central Kenya. Rain samples (n=218) were collected at intervals of 2 to 35 minutes (median of 3 minutes) depending on the rain rate (0.4 to 10.5 mm/hr). The volume-weighted mean rain values for δ18O, δ2H and D-excess (δ2H - 8* δ18O) were 0.1 ‰, 10.7 ‰, and 10.1 ‰. These values are more enriched than the annual weighted means reported for the area (-2.2 ‰, -7.6 ‰, and 11.0 ‰, respectively). Vapor was measured continuously at ~2Hz (DLT-100, Los Gatos Research), with an inverted funnel intake 4m above the ground surface. The mean vapor isotopic composition during the rain events was -10.0 +/- 1.2 ‰ (1 σ) for δ18O and -73.9 +/- 7.0 ‰ for δ2H. The difference between the rain sample isotopic composition and that of liquid in isotopic equilibrium with the corresponding vapor at the ambient temperature was 0.8 +/- 2.2 ‰ for δ18O and 6.2 +/- 7.0 ‰ for δ2H. This disequilibrium was found to correlate with the natural log of rain rate (R2 of 0.26 for δ18O and 0.46 for δ2H), with lower rain rates having larger

  12. Characteristics of rainfall queues for rain attenuation studies over radio links at subtropical and equatorial Africa

    NASA Astrophysics Data System (ADS)

    Alonge, Akintunde A.; Afullo, Thomas J.

    2014-08-01

    Attenuation due to precipitation remains an important design factor in the future deployment of terrestrial and earth-space communication radio links. Largely, there are concerted efforts to understand the dynamics of precipitation in attenuation occurrence at subtropical, tropical, and equatorial region of Africa. In this deliberate approach, rainfall spikes pertaining to rain cells are conceptualized as distinct rain spike traffic over radio links, by applying queueing theory concepts. The queue distributions at Durban (29°52'S, 30°58'E) and Butare (2°36'S, 29°44'E)—respectively, of subtropical and equatorial climates—are investigated from distrometer measurements. The data sets at both sites are observed over four rain regimes: drizzle, widespread, shower, and thunderstorm. The queue parameters of service time and inter-arrival of rain spikes traffic at both regions are found to be Erlang-k distributed (Ek) and exponentially distributed (M), respectively. It is established that the appearance of rain rates over radio links invariably follows a First Come, First Served (FCFS), multi-server (s), infinite queue, and semi-Markovian process, designated as M/Ek/s/∞/FCFS discipline. Modeled queue parameters at both regions are found to vary significantly over different regimes. However, these queue parameters over the entire data set suggest similar queue patterns at both sites. More importantly, power law relationships describing other queue-related parameters are formulated. The paper concludes by demonstrating an application of queueing theory for rainfall synthesis. The proposed technique will provide an alternative method of estimating rain cell sizes and rain attenuation over satellite and terrestrial links.

  13. Rain Check Application: Mobile tool to monitor rainfall in remote parts of Haiti

    NASA Astrophysics Data System (ADS)

    Huang, X.; Baird, J.; Chiu, M. T.; Morelli, R.; de Lanerolle, T. R.; Gourley, J. R.

    2011-12-01

    Rainfall observations performed uniformly and continuously over a period of time are valuable inputs in developing climate models and predicting events such as floods and droughts. Rain-Check is a mobile application developed in Google App Inventor Platform, for android based smart phones, to allow field researchers to monitor various rain gauges distributed though out remote regions of Haiti and send daily readings via SMS messages for further analysis and long term trending. Rainfall rate and quantity interact with many other factors to influence erosion, vegetative cover, groundwater recharge, stream water chemistry and runoff into streams impacting agriculture and livestock. Rainfall observation from various sites is especially significant in Haiti with over 80% of the country is mountainous terrain. Data sets from global models and limited number of ground stations do not capture the fine-scale rainfall patterns necessary to describe local climate. Placement and reading of rain gauges are critical to accurate measurement of rainfall.

  14. Turbulence effects on warm-rain formation in precipitating shallow convection revisited

    NASA Astrophysics Data System (ADS)

    Seifert, Axel; Onishi, Ryo

    2016-09-01

    Two different collection kernels which include turbulence effects on the collision rate of liquid droplets are used as a basis to develop a parameterization of the warm-rain processes autoconversion, accretion, and self-collection. The new parameterization is tested and validated with the help of a 1-D bin microphysics model. Large-eddy simulations of the rain formation in shallow cumulus clouds confirm previous results that turbulence effects can significantly enhance the development of rainwater in clouds and the occurrence and amount of surface precipitation. The detailed behavior differs significantly for the two turbulence models, revealing a considerable uncertainty in our understanding of such effects. In addition, the large-eddy simulations show a pronounced sensitivity to grid resolution, which suggests that besides the effect of sub-grid small-scale isotropic turbulence which is parameterized as part of the collection kernel also the larger turbulent eddies play an important role for the formation of rain in shallow clouds.

  15. NASA's DC-8 With Rain Mapping Radar

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In a joint venture between NASA and Japan's NASDA, scientists have been using satellites, airplanes, and boats to measure rain physics in and under thunderstorms over open water. This Quick Time movie shows the ER-2, a high altitude reconnaissance aircraft equipped with 8 lightening detectors and other instruments used to study hurricanes and thunderstorms. Earth science and weather studies are an important ongoing function of NASA and its affiliates.

  16. Simulator Of Rain In Flowing Air

    NASA Technical Reports Server (NTRS)

    Clayton, Richard M.; Cho, Young I.; Shakkottai, Parthasarathy; Back, Lloyd H.

    1989-01-01

    Report describes relatively inexpensive apparatus that creates simulated precipitation from drizzle to heavy rain in flowing air. Small, positive-displacement pump and water-injecting device positioned at low-airspeed end of converging section of wind tunnel 10 in. in diameter. Drops injected by array entrained in flow of air as it accelerates toward narrower outlet, 15 in. downstream. Outlet 5 in. in diameter.

  17. Ancient Jets of Fiery Rain

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2015-04-01

    Chondrules are intriguing millimeter-sized crystallized droplets that are abundant in chondrites, so named because of the presence of numerous chondrules. They have puzzled cosmochemists since they were described by English scientist H. C. Sorby in 1877. Everyone agrees that they formed as molten droplets of silicates, but nobody agrees on how the little things formed. Ideas range from impacts onto asteroids, primary condensation in the solar nebula, shock waves and/or lightening in the solar nebula, or by processes operating as planets began to form. A new twist on this last idea was investigated in a new way by Brandon Johnson (Massachusetts Institute of Technology, MIT) and co-authors David Minton and Jay Melosh (Purdue University), and Maria Zuber at MIT. Johnson and coworkers modeled the effects of impacts between planetesimals 100-1000 kilometers in diameter. When such objects hit each other, the first thing that happens is jetting of molten rock. Johnson and colleagues propose that the jets will subdivide into droplets as the jetted material is shot into space. They estimate that the chondrules would have the correct cooling rates (as determined from previous studies of chondrules) and the collision frequency would be high enough to produce abundant chondrules. Johnson and coworkers suggest that chondrules are a "byproduct of [planetary] accretion."

  18. Acid rain in Shenandoah National Park, Virginia

    USGS Publications Warehouse

    Rice, Karen C.; Deviney, Frank A.; Olson, Gordon

    2007-01-01

    Visitors to Shenandoah National Park (SNP) enjoy the animal and plant life and the scenery but may not realize how vulnerable these features are to various threats, such as invasion of exotic plants and insects, improper use of park resources by humans, and air and water pollution. The National Park Service strives to protect natural resources from such threats to ensure that the resources will be available for enjoyment now and in the future. Because SNP has limited influence over the air pollution that envelops the region, acidic deposition--commonly known as acid rain--is one of the more challenging threats facing park managers. With the help of U.S. Geological Survey (USGS) scientists, park managers can understand how acid rain interacts with ground- and surface-water resources, which enables them to explain why reductions in air pollution can help preserve park resources. Such understanding also provides essential insight into ecosystem processes, as managers strive to unravel and resolve other environmental problems that are interrelated to acid rain.

  19. Energetic photoelectrons and the polar rain

    NASA Technical Reports Server (NTRS)

    Decker, Dwight T.; Jasperse, J. R.; Winningham, J. D.

    1990-01-01

    In the daytime midlatitudes, the Low Altitude Plasma Instrument (LAPI) on board the Dynamics Explorer 2 satellite has observed photoelectrons with energies as high as 850 eV. These energetic photoelectrons are an extension of the 'classical' photoelectrons (less than 60 eV) and result from photoionization of neutrals by soft solar X-rays. Since these photoelectrons are produced wherever the solar flux is incident on the earth's atmosphere, they should be present in sunlit polar cap. But in the polar cap, over these same energies, there is a well-known electron population: the polar rain, a low intensity electron flux of magnetospheric origin. Thus, in the sunlit polar cap, an energetic population of electrons should consist of both an ionospheric (photoelectron) and a magnetospheric (polar rain) component. Using numerical solutions of an electron transport equation with appropriate boundary conditions and sunlit polar cap LAPI data, it is shown that the two populations (photoelectron and polar rain) are indeed present and are both needed to explain polar cap observations.

  20. Landslide triggering by rain infiltration

    USGS Publications Warehouse

    Iverson, Richard M.

    2000-01-01

    Landsliding in response to rainfall involves physical processes that operate on disparate timescales. Relationships between these timescales guide development of a mathematical model that uses reduced forms of Richards equation to evaluate effects of rainfall infiltration on landslide occurrence, timing, depth, and acceleration in diverse situations. The longest pertinent timescale is A/D0, where D0 is the maximum hydraulic diffusivity of the soil and A is the catchment area that potentially affects groundwater pressures at a prospective landslide slip surface location with areal coordinates x, y and depth H. Times greater than A/D0 are necessary for establishment of steady background water pressures that develop at (x, y, H) in response to rainfall averaged over periods that commonly range from days to many decades. These steady groundwater pressures influence the propensity for landsliding at (x, y, H), but they do not trigger slope failure. Failure results from rainfall over a typically shorter timescale H2/D0 associated with transient pore pressure transmission during and following storms. Commonly, this timescale ranges from minutes to months. The shortest timescale affecting landslide responses to rainfall is √(H/g), where g is the magnitude of gravitational acceleration. Postfailure landslide motion occurs on this timescale, which indicates that the thinnest landslides accelerate most quickly if all other factors are constant. Effects of hydrologic processes on landslide processes across these diverse timescales are encapsulated by a response function, R(t*) = √(t*/π) exp (-1/t*) - erfc (1/√t*), which depends only on normalized time, t*. Use of R(t*) in conjunction with topographic data, rainfall intensity and duration information, an infinite-slope failure criterion, and Newton's second law predicts the timing, depth, and acceleration of rainfall-triggered landslides. Data from contrasting landslides that exhibit rapid, shallow motion and slow, deep

  1. Intra-event isotope and raindrop size data of tropical rain reveal effects concealed by event averaged data

    NASA Astrophysics Data System (ADS)

    Managave, S. R.; Jani, R. A.; Narayana Rao, T.; Sunilkumar, K.; Satheeshkumar, S.; Ramesh, R.

    2016-08-01

    Evaporation of rain is known to contribute water vapor, a potent greenhouse gas, to the atmosphere. Stable oxygen and hydrogen isotopic compositions (δ18O and, δD, respectively) of precipitation, usually measured/presented as values integrated over rain events or monthly mean values, are important tools for detecting evaporation effects. The slope ~8 of the linear relationship between such time-averaged values of δD and δ18O (called the meteoric water line) is widely accepted as a proof of condensation under isotopic equilibrium and absence of evaporation of rain during atmospheric fall. Here, through a simultaneous investigation of the isotopic and drop size distributions of seventeen rain events sampled on an intra-event scale at Gadanki (13.5°N, 79.2°E), southern India, we demonstrate that the evaporation effects, not evident in the time-averaged data, are significantly manifested in the sub-samples of individual rain events. We detect this through (1) slopes significantly less than 8 for the δD-δ18O relation on intra-event scale and (2) significant positive correlations between deuterium excess ( d-excess = δD - 8*δ18O; lower values in rain indicate evaporation) and the mass-weighted mean diameter of the raindrops ( D m ). An estimated ~44 % of rain is influenced by evaporation. This study also reveals a signature of isotopic equilibration of rain with the cloud base vapor, the processes important for modeling isotopic composition of precipitation. d-excess values of rain are modified by the post-condensation processes and the present approach offers a way to identify the d-excess values least affected by such processes. Isotope-enabled global circulation models could be improved by incorporating intra-event isotopic data and raindrop size dependent isotopic effects.

  2. Possible impacts of climate change on freezing rain in south-central Canada using downscaled future climate scenarios

    NASA Astrophysics Data System (ADS)

    Cheng, C. S.; Auld, H.; Li, G.; Klaassen, J.; Li, Q.

    2007-01-01

    Freezing rain is a major atmospheric hazard in mid-latitude nations of the globe. Among all Canadian hydrometeorological hazards, freezing rain is associated with the highest damage costs per event. Using synoptic weather typing to identify the occurrence of freezing rain events, this study estimates changes in future freezing rain events under future climate scenarios for south-central Canada. Synoptic weather typing consists of principal components analysis, an average linkage clustering procedure (i.e., a hierarchical agglomerative cluster method), and discriminant function analysis (a nonhierarchical method). Meteorological data used in the analysis included hourly surface observations from 15 selected weather stations and six atmospheric levels of six-hourly National Centers for Environmental Prediction (NCEP) upper-air reanalysis weather variables for the winter months (November-April) of 1958/59-2000/01. A statistical downscaling method was used to downscale four general circulation model (GCM) scenarios to the selected weather stations. Using downscaled scenarios, discriminant function analysis was used to project the occurrence of future weather types. The within-type frequency of future freezing rain events is assumed to be directly proportional to the change in frequency of future freezing rain-related weather types The results showed that with warming temperatures in a future climate, percentage increases in the occurrence of freezing rain events in the north of the study area are likely to be greater than those in the south. By the 2050s, freezing rain events for the three colder months (December-February) could increase by about 85% (95% confidence interval - CI: ±13%), 60% (95% CI: ±9%), and 40% (95% CI: ±6%) in northern Ontario, eastern Ontario (including Montreal, Quebec), and southern Ontario, respectively. The increase by the 2080s could be even greater: about 135% (95% CI: ±20%), 95% (95% CI: ±13%), and 45% (95% CI: ±9%). For the

  3. Scavenging of radioactive soluble gases from inhomogeneous atmosphere by evaporating rain droplets.

    PubMed

    Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

    2015-05-01

    We analyze effects of inhomogeneous concentration and temperature distributions in the atmosphere, rain droplet evaporation and radioactive decay of soluble gases on the rate of trace gas scavenging by rain. We employ a one-dimensional model of precipitation scavenging of radioactive soluble gaseous pollutants that is valid for small gradients and non-uniform initial altitudinal distributions of temperature and concentration in the atmosphere. We assume that conditions of equilibrium evaporation of rain droplets are fulfilled. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the linear wave equation that describes propagation of a scavenging wave front. The obtained equation is solved by the method of characteristics. Scavenging coefficients are calculated for wet removal of gaseous iodine-131 and tritiated water vapor (HTO) for the exponential initial distribution of trace gases concentration in the atmosphere and linear temperature distribution. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for tritiated water vapor are in good agreement with the available atmospheric measurements.

  4. X-band radar field campaign data analysis for orographic/warm-rain precipitation processes

    NASA Astrophysics Data System (ADS)

    Porcacchia, Leonardo; Kirstetter, Pierre-Emmanuel; Gourley, Jonathan J.; Anagnostou, Marios N.; Anagnostou, Emmanouil N.; Bousquet, Olivier; Cheong, Boon-Leng; Maggioni, Viviana; Hong, Yang

    2016-04-01

    Accurate quantitative precipitation estimation over mountainous basins is of great importance because of their susceptibility to hazards such as flash floods, shallow landslides, and debris flows. It is usually hard to obtain reliable weather radar information in mountainous areas, due to difficulties connected to non-meteorological scattering and the elevation of the study sites. Such regions are particularly interested by orographic/warm-rain precipitation processes, characterized by no ice phase in the cloud and prevailing concentration of small drops in the drop size distribution. Field campaigns are able to provide complete and solid datasets in mountainous regions, thanks to mobile radars and the complementary information provided by rain gauges and disdrometers. This study analyzes datasets collected during the Hymex, IPHEX, and Colorado field campaigns in mountainous areas in Italy, France, North Carolina, and Colorado. Mobile X-band radars from the NOAA National Severe Storm Laboratory and the Advanced Radar Research Center at the University of Oklahoma are utilized. The X-band dual polarimetric radar data are corrected for attenuation through the SCOP algorithm, and evaluated against disdrometer and rain-gauge data. Warm-rain events are identified by looking at the Gorgucci, Cao-Zhang, and Kumjian-Ryzhkov parameter spaces relating polarimetric radar variables to precipitation development processes in the cloud and rain size distributions. A conceptual model for the vertical profile of precipitation and microphysical structure of the cloud is also derived, to be contrasted against other typical convective and stratiform profiles.

  5. Wind Tunnel Aerodynamic Characteristics of a Transport-type Airfoil in a Simulated Heavy Rain Environment

    NASA Technical Reports Server (NTRS)

    Bezos, Gaudy M.; Dunham, R. Earl, Jr.; Gentry, Garl L., Jr.; Melson, W. Edward, Jr.

    1992-01-01

    The effects of simulated heavy rain on the aerodynamic characteristics of an NACA 64-210 airfoil section equipped with leading-and trailing-edge high-lift devices were investigated in the Langley 14- by 22-Foot Subsonic Tunnel. The model had a chord of 2.5 ft, a span of 8 ft, and was mounted on the tunnel centerline between two large endplates. Aerodynamic measurements in and out of the simulated rain environment were obtained for dynamic pressures of 30 and 50 psf and an angle-of-attack range of 0 to 20 degrees for the cruise configuration. The rain intensity was varied to produce liquid water contents ranging from 16 to 46 gm/cu m. The results obtained for various rain intensity levels and tunnel speeds showed significant losses in maximum lift capability and increases in drag for a given lift as the liquid water content was increased. The results obtained on the landing configuration also indicate a progressive decrease in the angle of attack at which maximum lift occurred and an increase in the slope of the pitching-moment curve as the liquid water content was increased. The sensitivity of test results to the effects of the water surface tension was also investigated. A chemical was introduced into the rain environment that reduced the surface tension of water by a factor of 2. The reduction in the surface tension of water did not significantly alter the level of performance losses for the landing configuration.

  6. Wind Retrievals under Rain for Passive Satellite Microwave Radiometers and its Applications to Hurricane Tracking

    NASA Technical Reports Server (NTRS)

    Meissner, Thomas; Wentz, Frank J.

    2008-01-01

    We have developed an algorithm that retrieves wind speed under rain using C-hand and X-band channels of passive microwave satellite radiometers. The spectral difference of the brightness temperature signals due to wind or rain allows to find channel combinations that are sufficiently sensitive to wind speed but little or not sensitive to rain. We &ve trained a statistical algorithm that applies under hurricane conditions and is able to measure wind speeds in hurricanes to an estimated accuracy of about 2 m/s. We have also developed a global algorithm, that is less accurate but can be applied under all conditions. Its estimated accuracy is between 2 and 5 mls, depending on wind speed and rain rate. We also extend the wind speed region in our model for the wind induced sea surface emissivity from currently 20 m/s to 40 mls. The data indicate that the signal starts to saturate above 30 mls. Finally, we make an assessment of the performance of wind direction retrievals from polarimetric radiometers as function of wind speed and rain rate

  7. Radiative transfer for a three-dimensional raining cloud

    NASA Technical Reports Server (NTRS)

    Haferman, J. L.; Krajewski, W. F.; Smith, T. F.; Sanchez, A.

    1993-01-01

    Satellite-sensor-based microwave brightness temperatures for a three-dimensional raining cloud over a reflecting surface are computed by using a radiative transfer model based on the discrete-ordinates solution procedure. The three-dimensional model applied to a plane layer is validated by comparison with results from a one-dimensional model that is available in the literature. Results examining the effects of cloud height, rainfall rate, surface reflectance, rainfall footprint area, and satellite viewing position on one- and three-dimensional brightness temperature calculations are reported. The numerical experiments indicate that, under certain conditions, three-dimensional effects are significant in the analysis of satellite-sensor-based rainfall retrieval algorithms. The results point to the need to consider carefully three-dimensional effects as well as surface reflectance effects when interpreting satellite-measured radiation data.

  8. Experimental validation of heavy rain attenuation in E-band based on climate wind tunnel measurements at 77 GHz

    NASA Astrophysics Data System (ADS)

    Lewark, Ulrich J.; Mahler, Tobias; Antes, Jochen; Boes, Florian; Tessmann, Axel; Henneberger, Ralf; Kallfass, Ingmar; Zwick, Thomas

    2015-12-01

    Attenuation measurements through extreme rain in a climate wind tunnel are carried out to benchmark the possibility of wireless data transmission at 77 GHz during adverse weather conditions. Based on a network analyzer and external E-band mixers, the propagation loss at 77 GHz is obtained over a distance of 180 m using a corner reflector at the end of a 90-m tunnel. Comparing the results to prediction models like the ITU-R P.838, a large deviation of several tens of dB/km was found for high rain rates when the drop size distribution is neglected. In the paper, the authors use known attenuation models based on rain drop distribution functions to explain the high measured attenuation during the testing, demonstrating a large variation of specific attenuation under heavy rain at high microwave frequencies.

  9. Using high-speed photography to study undercatch in tipping-bucket rain gauges

    NASA Astrophysics Data System (ADS)

    Duchon, Claude; Fiebrich, Christopher; Grimsley, David

    2013-04-01

    To better understand the undercatch process associated with tipping-bucket rain gauges, we employed a high-speed camera normally used in determining the structure of lightning. The photo rate was set at 500 frames per second to observe the tipping of the bucket in a commonly used tipping-bucket rain gauge with its case removed. The photos showed detail never seen before as the bucket tipped from one side to the other. The Hydrologic Services Model TB 320 Calibration Device (Australia) was used to provide two fixed rain rates of 19.9 mm/h and 175.2 mm/h. The high time resolution images show there are usually multiple bounces of the bucket before it finally achieves its rest position on a nylon acorn post. With the higher rain rate, the force of the rain falling into the bucket apparently causes some sloshing when the bucket is nearly full. The sloshing results in a noticeable variable motion of the bucket assembly away from its rest position just prior to the beginning of a tip. We examined the data from four tips each at the low and high rain rates. The results show that the time from the perceived beginning of a tip to the time the bucket assembly is horizontal - the period during which undercatch occurs - is an average of 0.45 s for the eight cases. The average time from the perceived beginning of a tip to the first strike at the opposite post is 0.53 s. The linear speed of the tip of the lip of the bucket at first strike averages 0.5 m/s. When separated into high and low rain rates, parallel calculations show that their differences are unremarkable. The undercatch was 0.97% for the lower rain rate given above and 8.79% for the higher rain rate. Traditional laboratory measurements of percent undercatch using the Hydrologic Services Device mentioned earlier are in relatively close agreement with the photographically determined percent undercatch. We plan to discuss the procedure used to estimate the undercatch and present a slow-motion video of the tipping of a

  10. Observations of Precipitation Size and Fall Speed Characteristics within Coexisting Rain and Wet Snow

    NASA Technical Reports Server (NTRS)

    Yuter, Sandra E.; Kingsmill, David E.; Nance, Louisa B.; Loeffler-Mang, Martin

    2006-01-01

    at 0 C and 4% of the particles by volume for the region just below the isothermal layer where air temperatures rise from 0" to 0.5"C. As air temperatures increa sed above 0.5 C, the relative proportions of rain versus snow particl es shift dramatically and raindrops become dominant. The value of 0.5 C for the sharp transition in volume fraction from snow to rain is sl ightly lower than the range from 1 .l to 1.7 C often used in hydrolog ical models.

  11. Rain induced attenuation studies for V-band satellite communication in tropical region

    NASA Astrophysics Data System (ADS)

    Badron, Khairayu; Ismail, Ahmad Fadzil; Din, Jafri; Tharek, Abd. Rahman

    2011-04-01

    Satellite communications operating at 10 GHz and above in the tropics suffer severe signal degradation due to rain. Attenuation due to rain at 38 GHz had been measured for a period of 20 months in Malaysia. Analyses carried out include seasonal variations, diurnal effects and the annual cumulative distributions. Obtained results were compared with several established prediction models including the ITU-R. The rain fade characteristics were also investigated in determining the levels of signal loss and fading. In addition, the studies highlight several potential fade mitigation techniques that can be embarked. These fundamental aprehensions are very critical for future earth space communication link design and can be exploited as preliminary groundwork plan for the researchers as well as engineers.

  12. Principal modes of variation of rain-rate probability distributions

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Suhasini, R.

    1994-01-01

    Radar or satellite observations of an area generate sequences of rain-rate maps. From a gridded map a histogram of rain rates can be obtained representing the relative areas occupied by rain rates of various strengths. The histograms vary with time as precipitating systems in the area evolve and decay and amounts of convective and stratiform rain in the area change. A method of decomposing the histograms into linear combinations of a few empirical distributions with time-dependent coefficients is developed, using principal component analysis as a starting point. When applied to a tropical Atlantic dataset (GATE), two distributions emerge naturally from the analysis, resembling stratiform and convective rain-rate distributions in that they peak at low and high rain rates, respectively. The two 'modes' have different timescales and only the high-rain-rate mode has a statistically significant diurnal cycle. The ability of just two modes to describe rain variabiltiy over an area can explain why methods of estimating area-averaged rain rate from the area covered by rain rates above a certain threshold are so successful.

  13. Interception of caesium-contaminated rain by vegetation

    NASA Astrophysics Data System (ADS)

    Kinnersley, R. P.; Goddard, A. J. H.; Minski, M. J.; Shaw, G.

    A series of experiments were carried out to quantify the interception of rain-borne caesium by crops of grass ( Lolium perenne), broad beans ( Vicia faba) and wheat ( Triticum aestivum) under rainfall intensities typical of those encountered in the U.K. (1-18 mm h -1). The fraction of contamination deposited on the vegetation decreased with time, as the plant surface approached a saturation level of contamination. Surface contamination was dependent upon the total amount of rainfall rather than the rainfall intensity. The total surface water storage capacity of wheat and beans was determined, and found to approach a saturation level as total rainfall increased in a manner similar to the measured contamination levels. Total accumulation of caesium from aqueous solution onto bean leaves was found to increase linearly with time over the range of concentrations tested (0.0001-10 mM), the rate of accumulation increasing with concentration according to a power law. The combination of results obtained suggests that deposition of rain-borne contaminants could be modelled appropriately by a water storage capacity term and a "chemical term" derived from the contaminant concentration and its affinity for a particular plant surface.

  14. The phase of the crosspolarized signal generated by millimeter wave propagation through rain

    NASA Technical Reports Server (NTRS)

    Overstreet, W. P.; Bostian, C. W.

    1978-01-01

    Proposed schemes for cancelling rain-induced crosstalk in dual-polarized communications systems depend upon the phase relationships between the wanted and unwanted signals. This report investigates the phase relationship of the rain-generated crosspolarized signal relative to the copolarized signal. Theoretical results obtained from a commonly accepted propagation model are presented. Experimental data from the Communications Technology Satellite beacon and from the Comstar beacon are presented and the correlation between theory and data is discussed. An inexpensive semi-adaptive cancellation system is proposed and its performance expectations are presented. The implications of phase variations on a cancellation system are also discussed.

  15. Optical Rain Gauge Performance: Second Workshop on Optical Rain Gauge Measurements

    NASA Technical Reports Server (NTRS)

    Short, David A. (Editor); Thiele, Otto W. (Editor); Mcphaden, Michael J. (Editor)

    1994-01-01

    The primary focus of the workshop was on the performance and reliability of STi mini-Optical Rain Gauges in a number of environments, including deployments on ships and buoys in the western equatorial Pacific Ocean during the TOGA/COARE field experiment, deployments on buoys in U.S. coastal waters, and comparisons with other types of rain gauges on the Virginia coast and in Florida. The workshop was attended by 20 investigators, representing 10 different institutions, who gathered to present new results obtained since the first workshop (April 1993), to discuss problems, to consider solutions, and to chart future directions. Post-TOGA/COARE calibration studies were also presented.

  16. Planetary boundary layer dynamics over the Amazon rain forest

    NASA Astrophysics Data System (ADS)

    Pereiradeoliveira, Amauri

    Observations of the diurnal evolution of the planetary boundary layer (PBL) over the Amazon rain forest, in the area of the Amazon boundary layer experiment (ABLE) 2A and 2B experiments showed the existence of a low level circulation with low level nocturnal maxima winds. These circulations are shown to be induced by the thermal contrast between the river and the forest. A linear model was applied to identify the horizontal extent of these circulations and an associated perturbation pressure gradient consistent with the observations. A second order closure model was used to simulate changes in the PBL caused by the thermal circulation. Good agreement with the observations was obtained when the forcing was a horizontal pressure gradient equal to 0.5 mb/100km of limited vertical extent. The dynamics of the equatorial PBL was shown to be plausibly explained using a hypothesis of a river breeze circulation.

  17. Planetary Boundary Layer Dynamics Over the Amazon Rain Forest

    NASA Astrophysics Data System (ADS)

    Oliveira, Amauri Pereira De.

    1990-02-01

    Observations of the diurnal evolution of the Planetary Boundary Layer (PBL) over the Amazon rain forest, in the area of the ABLE 2A and 2B experiments showed the existence of a low level circulation with low level nocturnal maxima winds. These circulations are shown to be induced by the thermal contrast between the river and the forest. A linear model was applied to identify the horizontal extent of these circulations and an associated perturbation pressure gradient consistent with the observations. A second order closure model was used to simulate changes in the PBL caused by the thermal circulation. Good agreement with the observations was obtained when the forcing was a horizontal pressure gradient equal to 0.5 mb/100km of limited vertical extent. The dynamics of the equatorial PBL was shown to be plausibly explained using a hypothesis of a river breeze circulation.

  18. Radar Derived Spatial Statistics of Summer Rain. Volume 2; Data Reduction and Analysis

    NASA Technical Reports Server (NTRS)

    Konrad, T. G.; Kropfli, R. A.

    1975-01-01

    Data reduction and analysis procedures are discussed along with the physical and statistical descriptors used. The statistical modeling techniques are outlined and examples of the derived statistical characterization of rain cells in terms of the several physical descriptors are presented. Recommendations concerning analyses which can be pursued using the data base collected during the experiment are included.

  19. Assessment of measurement errors and dynamic calibration methods for three different tipping bucket rain gauges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three different models of tipping bucket rain gauges (TBRs), viz. HS-TB3 (Hydrological Services Pty Ltd), ISCO-674 (Isco, Inc.) and TR-525 (Texas Electronics, Inc.), were calibrated in the lab to quantify measurement errors across a range of rainfall intensities (5 mm.h-1 to 250 mm.h-1) and three di...

  20. Technological options for acid rain control

    SciTech Connect

    Princiotta, F.T.; Sedman, C.B.

    1993-01-01

    The paper discusses technological options for acid rain control. Compliance with Title IV of the Clean Air Act Amendments of 1990 will require careful scrutiny of a number of issues before selecting control options to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions. One key consideration is the effect of fuel switching or control technology upon the existing dust collector, with additional air toxics legislation looming ahead. A number of likely SO2 and NOx retrofit technologies and estimated costs are presented, along with results of retrofit case studies. New hybrid particulate controls are also being developed to meet future requirements.

  1. Acid rain reduced in eastern United States

    SciTech Connect

    Bowersox, V.C.; Lynch, J.A.; Grimm, J.W.

    1997-12-31

    Sulfate and free hydrogen ion concentrations in precipitation decreased 10 to 25 percent over large areas of the eastern United States in 1995. The largest decreases in both ions occurred in and downwind of the Ohio River Valley, the same area where Phase I of the 1990 Clean Air Act Amendments set limitations, effective January 1, 1995, on sulfur dioxide emissions from affected coal-fired sources. Based on our analysis of precipitation chemistry and emissions data, we conclude that substantial declines in acid rain occurred in the eastern United States in 1995 because of large reductions in sulfur dioxide emissions in the same region.

  2. Monitoring Fires in Southwestern Amazonia Rain Forests

    NASA Astrophysics Data System (ADS)

    Brown, I. Foster; Schroeder, Wilfrid; Setzer, Alberto; de Los Rios Maldonado, Monica; Pantoja, Nara; Duarte, Alejandro; Marengo, Jose

    2006-06-01

    From mid-July to mid-October 2005, an environmental disaster unfolded in the trinational region of Madre de Dios, Peru; Acre, Brazil; and Pando, Bolivia (the MAP region), in southwestern Amazonia. A prolonged dry season and human-initiated fires resulted in smoke pollution affecting more than 400,000 persons, fire damage to over 300,000 hectares of rain forest, and over US$50 million of direct economic losses. Indicators suggest that anomalous drought conditions could occur again this year.

  3. The greenhouse effect and acid rain

    SciTech Connect

    Traeger, R.K.

    1990-01-01

    The concentrations of carbon dioxide, methane, sulfur dioxide, nitrous oxides and chlorofluorocarbons is increasing in the earth's atmosphere. Increased concentrations of these trace gases could lead to global warming, increased acid rain and increased UV radiation on the earth's surface; however, the actual impacts are still uncertain and are also the subject of great debate. Application of clean'' energy sources such as geothermal are obviously desirable for decreasing these effects and improving our overall general environment. This paper briefly summarizes the global environment concerns, providing a backdrop for the following papers which describe the geothermal role in future environmental considerations. 5 refs., 2 figs., 1 tab.

  4. Fog/cloud and rain chemistry in northern coastal California

    SciTech Connect

    Bicknell, S.H.; Lemcke, S.

    1987-07-01

    Fog, clouds and rain were sampled for 2 years at Redwood National Park (RNP) and one year at Arcata and Oakland. Fog and cloud water samples were more acidic and contained higher concentrations of Ca, Mg, K, Na, NH4, SO4, NO3 and Cl, than rain samples at all sites. Cloud/fog water and rain sample chemistry was not different for RNP and Arcata; but Oakland samples were significantly more acid and had higher concentrations of all elements. RNP and Arcata cloud/fog samples were more acid and contained higher elemental concentrations than expected under pristine conditions. Average pH's were: RNP cloud/fog - 4.12, RNP rain - 4.63, Arcata cloud/fog - 4.00, Arcata rain - 4.66, Oakland cloud/fog - 3.87, Oakland rain - 4.37.

  5. Geographical distribution and temporal variation of rain acidity over China

    SciTech Connect

    Wen-Xing Wang; Yan-Bo Pang; Guo-An Ding

    1996-12-31

    In recent decade, large areas of acid rain have appeared in China. With the increasing emission of SO{sub 2} and NO{sub x} year by year, the acidity of precipitation has increased, and the acid rain area is expanding. Presently, the acid rain in China has become the third largest area of acid rain in the world, next to Europe and North America. The Chinese government took action against acid rain and planned a five-year National Acid Deposition Research Project. The space-time distribution and variation of rain acidity described in this paper is a part of this project. China is a large country. The area is almost equal to that of Europe. Its climate varies greatly and spans the tropics, subtropics, temperate and frigid zone. There is a varied topography including mountain, hilly country, desert and plain, on the other hand the distribution of anthropogenic sources are not even. All of the human and natural factors caused different chemical composition in different parts of China, the acidity of precipitation varies also. The acidity of the precipitation is the most important parameter in the acid rain research. In order to obtain the regional representative distribution of rain acidity, National Acidic Deposition Research Monitoring Network with 261 monitoring sites was established in 1992. This paper summarizes the rain acidity of 21355 precipitation samples, and gave the annual, seasonal, and the monthly pH contours. Results show that the acid rain area has expanded from the south during winter. Regional differences of monthly acid precipitation exists, generally, the rain acidity level is higher during summer and fall and lower during winter and spring in the northern provinces. The 9 opposite is the case in the southern provinces. The central areas are in a transitional situation. The geographical distribution and temporal variation of rain acidity are quite different from North America and Europe.

  6. Response of soybean seed germination to cadmium and acid rain.

    PubMed

    Liu, Ting Ting; Wu, Peng; Wang, Li Hong; Zhou, Qing

    2011-12-01

    Cadmium (Cd) pollution and acid rain are the main environmental issues, and they often occur in the same agricultural region. Nevertheless, up to now, little information on the combined pollution of Cd(2+) and acid rain action on crops were presented. Here, we investigated the combined effect of Cd(2+) and acid rain on the seed germination of soybean. The results indicated that the single treatment with the low level of Cd(2+) (0.18, 1.0, 3.0 mg L(-1)) or acid rain (pH ≥3.0) could not affect the seed germination of soybean, which was resulted in the increased activities of peroxidase and catalase. The single treatment with the high concentration of Cd(2+) (>6 mg L(-1)) or acid rain at pH 2.5 decreased the activities of peroxidase and catalase, damaged the cell membrane and then decreased the seed germination of soybean. Meanwhile, the same toxic effect was observed in the combined treatment with Cd(2+) and acid rain, and the combined treatment had more toxic effect than the single treatment with Cd(2+) or acid rain. Thus, the combined pollution of Cd(2+) and acid rain had more potential threat to the seed germination of soybean than the single pollution of Cd(2+) or acid rain.

  7. New rain shed (Building No. 241) interior showing posts, braces, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    New rain shed (Building No. 241) interior showing posts, braces, and roof structure. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  8. Estimation of Trends in Distributions of One-Minute Rain Rates Over the UK to Assess Impacts on Telecommunications

    NASA Astrophysics Data System (ADS)

    Bellerby, Tim; Ranatunga, Channa; Paulson, Kevin

    2014-05-01

    It is known that the rain rate exceeded 0.01% of the time has experienced an increasing trend, in the UK, over the last twenty years. It is very likely that rain fade and outage experience a similar trend. This paper presents a method, applicably globally, to estimate these trends. The input data are parameters easily extracted from numerical weather prediction reanalysis data. The method is verified using rain gauge data from the UK. Dynamic fading due to rain and wet snow tends to be larger than that due to other mechanisms on terrestrial and Earth-space links at frequencies above approximately 5 GHz. The International Telecommunication Union (ITU-R) maintains a set of models for predicting average annual distributions of rain fade, with a one-minute integration time, on individual links. An important parameter in these models of rain fade is the one-minute rain rate exceeded for 0.01% of an average year (R0.01%). Several recent reports have suggested that trends in climate parameters could be having significant effect on telecommunications systems over their lifetime. A satellite communications system has a typical life-cycle of 30 years, from initial conception to decommissioning. The objective of this work is to develop a method to estimate trends in the R0.01% rain rate, globally, using readily accessible data. A relationship is postulated between very low resolution rain parameters from Numerical Weather Prediction (NWP) reanalysis data and the one-minute averaged, point rain rates required for radio regulation, and the optimization of network spectral efficiency and performance. Trends in these parameters can then be linked to trends in one-minute rain rates. The transformation of reanalysis parameters to one-minute rain rate CCDF parameters has been optimized to provide the best fit to the 743 experimental CCDF statistics, acquired from over the 139 locations, archived in the database of the ITU-R Study Group 3: DBSG3. Inherent in this process is the

  9. Rain volume estimation over areas using satellite and radar data

    NASA Technical Reports Server (NTRS)

    Doneaud, Andre A.; Vonderhaar, T. H.; Johnson, L. R.; Laybe, P.; Reinke, D.

    1987-01-01

    The analysis of 18 convective clusters demonstrates that the extension of the Area-Time-Integral (ATI) technique to the use of satellite data is possible. The differences of the internal structures of the radar reflectivity features, and of the satellite features, give rise to differences in estimating rain volumes by delineating area; however, by focusing upon the area integrated over the lifetime of the storm, it is suggested that some of the errors produced by the differences in the cloud geometries as viewed by radar or satellite are minimized. The results are good and future developments should consider data from different climatic regions and should allow for implementation of the technique in a general circulation model.

  10. Resuspension of Aerosol Particles from Evaporated Rain Drops to the Coarse Mode

    NASA Astrophysics Data System (ADS)

    Wang, H.; Easter, R. C.; Ganguly, D.; Singh, B.; Rasch, P. J.

    2015-12-01

    Precipitation scavenging (i.e., wet removal) has long been recognized as one of the major removal processes for tropospheric aerosol particles, and the dominant one for accumulation-mode size particles. When rain drops evaporate, the aerosol material contained in drops is resuspended, and this process has received much less attention. Unlike the resuspension from evaporated cloud droplets, the aerosol particles resuspended from evaporated rain drops have much larger sizes than most of the aerosol particles that acted as cloud condensation nuclei (CCN), became cloud borne, and then were collected by rain drops, because each rain drop generally collects thousands of cloud droplets. Here we present some aspects of this resuspension process obtained from modeling studies. First, we investigate some details of the process using a simple drop-size resolved model of raindrop evaporation in sub-saturated air below cloud base. Using these results, we then investigate different treatments of this process in a global aerosol and climate model that employs a modal aerosol representation. Compared to the model's original treatment of this process in which rain-borne aerosol is resuspended to the mode that it came from with its original size, the new treatment that resuspends to the coarse mode produces notable reductions in global CCN concentrations, as well as sulfate, black carbon, and organic aerosol mass, because the resuspended aerosol particles have much shorter lifetimes due to their larger sizes. Somewhat surprisingly, there are also notable reductions in coarse-mode sea salt and mineral dust burdens. These species are resuspended to the coarse mode in both the original and new treatments, but these resuspended particles are fewer in number and larger in size in the new treatment. This finding highlights some issues of the modal aerosol treatment for coarse mode particles.

  11. Validation of the H-SAF precipitation product H03 over Greece using rain gauge data

    NASA Astrophysics Data System (ADS)

    Feidas, H.; Porcu, F.; Puca, S.; Rinollo, A.; Lagouvardos, C.; Kotroni, V.

    2016-11-01

    This paper presents an extensive validation of the combined infrared/microwave H-SAF (EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management) precipitation product H03, for a 1-year period, using gauge observations from a relatively dense network of 233 stations over Greece. First, the quality of the interpolated data used to validate the precipitation product is assessed and a quality index is constructed based on parameters such as the density of the station network and the orography. Then, a validation analysis is conducted based on comparisons of satellite (H03) with interpolated rain gauge data to produce continuous and multi-categorical statistics at monthly and annual timescales by taking into account the different geophysical characteristics of the terrain (land, coast, sea, elevation). Finally, the impact of the quality of interpolated data on the validation statistics is examined in terms of different configurations of the interpolation model and the rain gauge network characteristics used in the interpolation. The possibility of using a quality index of the interpolated data as a filter in the validation procedure is also investigated. The continuous validation statistics show yearly root mean squared error (RMSE) and mean absolute error (MAE) corresponding to the 225 and 105 % of the mean rain rate, respectively. Mean error (ME) indicates a slight overall tendency for underestimation of the rain gauge rates, which takes large values for the high rain rates. In general, the H03 algorithm cannot retrieve very well the light (< 1 mm/h) and the convective type (>10 mm/h) precipitation. The poor correlation between satellite and gauge data points to algorithm problems in co-locating precipitation patterns. Seasonal comparison shows that retrieval errors are lower for cold months than in the summer months of the year. The multi-categorical statistics indicate that the H03 algorithm is able to discriminate efficiently

  12. Cloud and rain liquid water statistics in the CHUVA campaign

    NASA Astrophysics Data System (ADS)

    Calheiros, Alan J. P.; Machado, Luiz A. T.

    2014-07-01

    The purpose of this study is to present statistics related to the integration of cloud and rain liquid water and the profiles for different cloud types and regimes. From 2010 to 2012, the CHUVA project collected information regarding cloud and rain characteristics in different precipitation regimes in Brazil. CHUVA had four field campaigns between 2010 and 2011, located in the North, Northeast and Southeast regions of Brazil, covering the semi-arid, Amazon, coastal and mountain regions. The synergy of several instruments allowed us to classify rain events and describe the cloud processes regionally. Microwave radiometers, LiDAR, radar, and disdrometers were employed in this study. The rain type classification was made using vertical profiles of reflectivity (VPR) and polarimetric variables from dual polarization radar (XPOL). The integrated liquid water (ILWC) for non-precipitating clouds was retrieved with a microwave ground-based radiometer using a neural network. For rainy conditions, the profiles from the rain liquid water content (LWCR) and their integrated (ILWR) properties were estimated by Micro Rain Radar (MRR) and XPOL VPRs. For non-precipitating clouds, the ILWC values were larger for the sites in tropical regions, in particular near the coast, than for Southeast Brazil. For rainy cases, distinct LWCR profiles were observed for different rain classifications and regions. The differences are small for low rain rates and a distinction between different rainfall regimes is more evident for high rain rates. Vale and Belém clouds present the deepest layers and largest convective rain rates. The clouds in the Southeast region of Brazil (Vale do Paraíba) and North region (Belém) showed the largest reflectivity in the mixed and glaciated layers, respectively. In contrast, the Northeast coastal site (e.g. Fortaleza) showed larger values in the warm part of the clouds. Several analyses are presented, describing the cloud processes and the differences among the

  13. Capabilities of the Johnson SB distribution in estimating rain variables

    NASA Astrophysics Data System (ADS)

    D'Adderio, Leo Pio; Cugerone, Katia; Porcù, Federico; De Michele, Carlo; Tokay, Ali

    2016-11-01

    Numerous fields of atmospheric and hydrological sciences require the parametric form of the raindrop size distribution (DSD) to estimate the rainfall rate from radar observables as well as in cloud resolving and weather forecasting models. This study aims to investigate the capability of the Johnson SB distribution (JSB) in estimating rain integral parameters. Specifically, rainfall rate (R), reflectivity factor (Z) and mean mass diameter (Dmass) estimated by JSB are compared with those estimated by a three-parameter Gamma distribution, widely used by radar meteorologists and atmospheric physicists to model natural DSD. A large dataset consisting of more than 155,000 one-minute DSD, from six field campaigns of Ground Validation (GV) program of NASA/JAXA Global Precipitation Measurement mission (GPM), is used to test the performance of both JSB and Gamma distribution. The available datasets cover a wide range of rain regimes because of the field campaigns were carried out in different seasons and locations. Correlation coefficient, bias, root mean square error (RMSE) and fractional standard error (FSE) between estimated and measured integral parameters are calculated to compare the performances of the two distributions. The capability of JSB in estimating the integral parameters, especially R and Z, resulted very close to that of Gamma distribution. In particular, for light precipitation, JSB is superior to Gamma distribution in estimating R with FSE of 11% with respect to values ranging between 25% and 37% about for Gamma. Comparison of the estimated and measured DSDs shows that the JSB distribution reproduces the natural DSD quite accurately.

  14. Space Radar Image of Randonia Rain Cell

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This multi-frequency space radar image of a tropical rainforest in western Brazil shows rapidly changing land use patterns and it also demonstrates the capability of the different radar frequencies to detect and penetrate heavy rainstorms. This color image was created by combining the three separate radar frequencies into a composite image. The three black and white images below represent the individual frequencies. The lower left image, X-band vertically transmitted and received, is blue in the color image; the lower center image, C-band horizontally transmitted and vertically received is green; and the lower right image, L-band horizontally transmitted and vertically received is red. A heavy downpour in the lower center of the image appears as a black 'cloud' in the X-band image, the same area is shows up faintly in the C-band image, and is invisible in the L-band image. When combined in the color image, the rain cell appears red and yellow. Although radar can usually 'see' through clouds, short radar wavelengths (high frequency), such as X and C-band, can be changed by unusually heavy rain cells. L-band, at a 24 cm (9 inches) wavelength, is unaffected by such rain cells. By analyzing the way the radar changes, scientist can estimate rainfall rates. The area shown is in the state of Rondonia, in western Brazil. The pink areas are pristine tropical rainforest, and the blue and green patches are areas where the forest has been cleared for agriculture. Cleared areas are typically able to support intense farming for a only few years, before soil erosion renders the fields unusable. Radar imaging can be used to monitor not only the rainforest destruction, but also the rates of recovery of abandoned fields. This image is 35.2 kilometers by 21.3 kilometers (21.8 miles by 13.2 miles) and is centered at 11.2 degrees south latitude, 61.7 degrees west longitude. North is toward the upper left. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic

  15. A Sensitivity Analysis of the Impact of Rain on Regional and Global Sea-Air Fluxes of CO2

    PubMed Central

    Shutler, J. D.; Land, P. E.; Woolf, D. K.; Quartly, G. D.

    2016-01-01

    The global oceans are considered a major sink of atmospheric carbon dioxide (CO2). Rain is known to alter the physical and chemical conditions at the sea surface, and thus influence the transfer of CO2 between the ocean and atmosphere. It can influence gas exchange through enhanced gas transfer velocity, the direct export of carbon from the atmosphere to the ocean, by altering the sea skin temperature, and through surface layer dilution. However, to date, very few studies quantifying these effects on global net sea-air fluxes exist. Here, we include terms for the enhanced gas transfer velocity and the direct export of carbon in calculations of the global net sea-air fluxes, using a 7-year time series of monthly global climate quality satellite remote sensing observations, model and in-situ data. The use of a non-linear relationship between the effects of rain and wind significantly reduces the estimated impact of rain-induced surface turbulence on the rate of sea-air gas transfer, when compared to a linear relationship. Nevertheless, globally, the rain enhanced gas transfer and rain induced direct export increase the estimated annual oceanic integrated net sink of CO2 by up to 6%. Regionally, the variations can be larger, with rain increasing the estimated annual net sink in the Pacific Ocean by up to 15% and altering monthly net flux by > ± 50%. Based on these analyses, the impacts of rain should be included in the uncertainty analysis of studies that estimate net sea-air fluxes of CO2 as the rain can have a considerable impact, dependent upon the region and timescale. PMID:27673683

  16. A Sensitivity Analysis of the Impact of Rain on Regional and Global Sea-Air Fluxes of CO2.

    PubMed

    Ashton, I G; Shutler, J D; Land, P E; Woolf, D K; Quartly, G D

    The global oceans are considered a major sink of atmospheric carbon dioxide (CO2). Rain is known to alter the physical and chemical conditions at the sea surface, and thus influence the transfer of CO2 between the ocean and atmosphere. It can influence gas exchange through enhanced gas transfer velocity, the direct export of carbon from the atmosphere to the ocean, by altering the sea skin temperature, and through surface layer dilution. However, to date, very few studies quantifying these effects on global net sea-air fluxes exist. Here, we include terms for the enhanced gas transfer velocity and the direct export of carbon in calculations of the global net sea-air fluxes, using a 7-year time series of monthly global climate quality satellite remote sensing observations, model and in-situ data. The use of a non-linear relationship between the effects of rain and wind significantly reduces the estimated impact of rain-induced surface turbulence on the rate of sea-air gas transfer, when compared to a linear relationship. Nevertheless, globally, the rain enhanced gas transfer and rain induced direct export increase the estimated annual oceanic integrated net sink of CO2 by up to 6%. Regionally, the variations can be larger, with rain increasing the estimated annual net sink in the Pacific Ocean by up to 15% and altering monthly net flux by > ± 50%. Based on these analyses, the impacts of rain should be included in the uncertainty analysis of studies that estimate net sea-air fluxes of CO2 as the rain can have a considerable impact, dependent upon the region and timescale.

  17. Warm Rain Processes over the Tropical Oceans and Implications on Climate Change: Results from TRMM and GEOS GCM

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, H. T.

    2004-01-01

    In this talk, we will first show results from TRMM data regarding the characteristics of warm rains over the tropical oceans, and the dependence of rate of warm rain production on sea surface temperature. Results lead to the hypothesis that warm rain production efficiency, i.e., autoconversion, may be increased in a warm climate. We use the GEOS-II GCM to test this hypothesis. Our modeling results show that in a climate with increased rate of autoconversion, the total rain amount is increased, with warm rain contributing to larger portion of the increase. The abundant rainout of warm precipitation causes a reduction of low and middle cloud amount due to rainout, and reduced high clouds due to less water vapor available for ice-phase convection. However, clod radiation feedback caused by the increased rainfall efficiency, leads to differential vertical heating/cooling producing a more unstable atmosphere, allowing, more intense, but isolated penetrative convection, with contracted anvils to develop. Results also show that increased autoconversion reduces the convective adjustment time scale, resulting in faster recycling of atmospheric water. Most interestingly, the increased low level heating associated with warm rain leads to more energetic Madden and Julian oscillations in the tropics, with well-defined eastward propagation. While reducing the autoconversion leads to an abundant mix of westward and eastward tropical disturbances on daily to weekly time scales. The crucial link of precipitation microphysical processes to climate change including the effects of aerosols will be discussed.

  18. Warm Rain Processes Over the Tropical Oceans and Implications on Climate Change: Results from TRMM and GOES GCM

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Wu, H. T.

    2004-01-01

    In this talk, we will first show results from TRMM data regarding the characteristics of warm rains over the tropical oceans, and the dependence of rate of warm rain production on sea surface temperature. Results lead to the hypothesis that warm rain production efficiency, i.e., autoconversion, may be increased in a warm climate. We use the GEOS-II GCM to test this hypothesis. Our modeling results show that in a climate with increased rate of autoconversion, the total rain amount is increased, with warm rain contributing to a larger portion of the increase. The abundant rainout of warm precipitation causes a reduction of low and middle cloud amount due to rainout, and reduced high clouds due to less water vapor available for ice-phase convection. However, clod radiation feedback caused by the increased rainfall efficiency, leads to differential vertical heating/cooling producing a more unstable atmosphere, allowing, more intense, but isolated penetrative convection, with contracted anvils to develop. Results also show that increased autoconversion reduces the convective adjustment time scale, resulting in faster recycling of atmospheric water. Most interestingly, the increased low level heating associated with warm rain leads to more energetic Madden and Julian oscillations in the tropics, with well-defined eastward propagation. While reducing the autoconversion leads to an abundant mix of westward and eastward tropical disturbances on daily to weekly time scales. The crucial link of precipitation microphysical processes to climate change including the effects of aerosols will be discussed.

  19. Estimates of the statistical two-dimensional spatial structure in rain over a small network of disdrometers

    NASA Astrophysics Data System (ADS)

    Jameson, A. R.; Larsen, M. L.

    2016-06-01

    Microphysical understanding of the variability in rain requires a statistical characterization of different drop sizes both in time and in all dimensions of space. Temporally, there have been several statistical characterizations of raindrop counts. However, temporal and spatial structures are neither equivalent nor readily translatable. While there are recent reports of the one-dimensional spatial correlation functions in rain, they can only be assumed to represent the two-dimensional (2D) correlation function under the assumption of spatial isotropy. To date, however, there are no actual observations of the (2D) spatial correlation function in rain over areas. Two reasons for this deficiency are the fiscal and the physical impossibilities of assembling a dense network of instruments over even hundreds of meters much less over kilometers. Consequently, all measurements over areas will necessarily be sparsely sampled. A dense network of data must then be estimated using interpolations from the available observations. In this work, a network of 19 optical disdrometers over a 100 m by 71 m area yield observations of drop spectra every minute. These are then interpolated to a 1 m resolution grid. Fourier techniques then yield estimates of the 2D spatial correlation functions. Preliminary examples using this technique found that steadier, light rain decorrelates spatially faster than does the convective rain, but in both cases the 2D spatial correlation functions are anisotropic, reflecting an asymmetry in the physical processes influencing the rain reaching the ground not accounted for in numerical microphysical models.

  20. BOREAS HYD-9 Belfort Rain Gauge Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Kouwen, Nick; Soulis, Ric; Jenkinson, Wayne; Graham, Allyson; Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-6 team collected several data sets related to the moisture content of soil and overlying humus layers. This data set contains water content measurements of the moss/humus layer, where it existed. These data were collected along various flight lines in the Southern Study Area (SSA) and Northern Study Area (NSA) during 1994. The data are available in tabular ASCII files. The HYD-9 Belfort rain gauge data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  1. Rain Forests: Do They Hold Up the Sky?

    ERIC Educational Resources Information Center

    Shaw, Donna Gail; Dybdahl, Claudia S.

    1992-01-01

    This paper uses the topic of rain forests to demonstrate how a meaningful and relevant Science, Technology, and Society program can be designed for intermediate-level students. Students create and immerse themselves in a tropical rain forest, explore the forest ecosystem and peoples, and consider solutions to the problem of deforestation. (JDD)

  2. 40 CFR 75.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false General Acid Rain Program provisions. 75.3 Section 75.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING General § 75.3 General Acid Rain Program provisions....

  3. 40 CFR 75.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false General Acid Rain Program provisions. 75.3 Section 75.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING General § 75.3 General Acid Rain Program provisions....

  4. Acid Rain, pH & Acidity: A Common Misinterpretation.

    ERIC Educational Resources Information Center

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  5. 40 CFR 75.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false General Acid Rain Program provisions. 75.3 Section 75.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING General § 75.3 General Acid Rain Program provisions....

  6. 40 CFR 75.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false General Acid Rain Program provisions. 75.3 Section 75.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING General § 75.3 General Acid Rain Program provisions....

  7. 40 CFR 75.3 - General Acid Rain Program provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false General Acid Rain Program provisions. 75.3 Section 75.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING General § 75.3 General Acid Rain Program provisions....

  8. Elementary Acid Rain Kit, Interdisciplinary, Grades 4-8.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.; And Others

    An interdisciplinary approach for teaching about acid rain is offered in this curriculum guide for teachers of grades 4-8. Skill and concept areas of science, math, social studies, art, and the language arts are developed in 12 activities which focus on the acid rain problems. A matrix of the activities and subject areas indicates the coverage…

  9. The Effects of Rain Garden Size on Hydrologic Performance

    EPA Science Inventory

    Rain gardens are vegetated depressions designed to accept stormwater runoff. Manuals and guidance documents recommend sizing rain garden cells from 3% to 43% of the associated drainage area, based on factors including soil type, slope, amount of impervious cover in the drainage ...

  10. Detail of old rain shed (Building No. 43) showing vertical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of old rain shed (Building No. 43) showing vertical posts. Note rock foundations of wood tanks once located under the rain shed on the ground at center of photograph. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  11. Flow Dynamics and Nutrient Reduction in Rain Gardens

    EPA Science Inventory

    The hydrological dynamics and changes in stormwater nutrient concentrations within rain gardens were studied by introducing captured stormwater runoff to rain gardens at EPA’s Urban Water Research Facility in Edison, New Jersey. The runoff used in these experiments was collected...

  12. A Rain Garden for Our School: Becoming Environmental Stewards

    ERIC Educational Resources Information Center

    McFadyen, Joy

    2012-01-01

    In this article, the author talks about a rain garden project at Hampton Elementary School in Bay City, Michigan. The goal of the project was to slow and filter silt-laden runoff (from parking lots, sidewalks, and playground) on its path to Saginaw Bay in Lake Huron. In addition, doing so, the rain gardens would demonstrate to the township, city,…

  13. The Effect of Rain on Air-Water Gas Exchange

    NASA Technical Reports Server (NTRS)

    Ho, David T.; Bliven, Larry F.; Wanninkhof, Rik; Schlosser, Peter

    1997-01-01

    The relationship between gas transfer velocity and rain rate was investigated at NASA's Rain-Sea Interaction Facility (RSIF) using several SF, evasion experiments. During each experiment, a water tank below the rain simulator was supersaturated with SF6, a synthetic gas, and the gas transfer velocities were calculated from the measured decrease in SF6 concentration with time. The results from experiments with IS different rain rates (7 to 10 mm/h) and 1 of 2 drop sizes (2.8 or 4.2 mm diameter) confirm a significant and systematic enhancement of air-water gas exchange by rainfall. The gas transfer velocities derived from our experiment were related to the kinetic energy flux calculated from the rain rate and drop size. The relationship obtained for mono-dropsize rain at the RSIF was extrapolated to natural rain using the kinetic energy flux of natural rain calculated from the Marshall-Palmer raindrop size distribution. Results of laboratory experiments at RSIF were compared to field observations made during a tropical rainstorm in Miami, Florida and show good agreement between laboratory and field data.

  14. Acid rain compliance: The need for regulatory guidance

    SciTech Connect

    Solomon, B.D.

    1993-07-01

    This article presents a broad view of the need for regulatory guidance when confronting the problem of acid rain. The two major topics addressed are (1) Why is guidance needed and (2) What kind of guidance is needed. Discussion of rate and accounting treatment of allowances, acid rain compliance planning, and allowance trading and energy efficiency are included.

  15. Rain Garden Research at EPA's Urban Watershed Research Facility

    EPA Science Inventory

    I have been invited to give a presentation at the 2009 National Erosion Conference in Hartford, CT, on October 27-28, 2009. My presentation discusses the research on sizing of rain gardens that is being conducted using the large, parking lot rain gardens on-site. I discuss the ...

  16. Comparison of satellite IR rain estimates with radar rain observations in hurricanes

    NASA Technical Reports Server (NTRS)

    Morris, K. Robert; Negri, Andrew J.; Adler, Robert F.

    1988-01-01

    Radar-observed rainrates and rain areas obtained for the Hurricanes Frederic (1979), Alicia (1983), and Diana (1984) were used in conjunction with GOES IR data to examine the validity of three satellite IR rain estimation techniques: the Arkin (1983) method, the Negri-Adler-Wetzel (1984) technique, and the convective-stratiform technique of Adler and Negri (1987). The Alicia hurricane was also monitored using the subjective manual technique of Spayd and Scofield (1984). It is shown that the success of IR techniques in identifying areas of rainfall depends on the hurricane feature being addressed. Thus, the three objective IR techniques were unable to identify the locations of radar-observed eyewall and inner band precipitation areas because of strong vertical wind shear in the eyewall and the lack of the vertical extent of stratiform precipitation beneath the central dense overcast.

  17. Millennial-scale dynamics of southern Amazonian rain forests.

    PubMed

    Mayle, F E; Burbridge, R; Killeen, T J

    2000-12-22

    Amazonian rain forest-savanna boundaries are highly sensitive to climatic change and may also play an important role in rain forest speciation. However, their dynamics over millennial time scales are poorly understood. Here, we present late Quaternary pollen records from the southern margin of Amazonia, which show that the humid evergreen rain forests of eastern Bolivia have been expanding southward over the past 3000 years and that their present-day limit represents the southernmost extent of Amazonian rain forest over at least the past 50,000 years. This rain forest expansion is attributed to increased seasonal latitudinal migration of the Intertropical Convergence Zone, which can in turn be explained by Milankovitch astronomic forcing.

  18. Interactions between greenhouse gas policies and acid rain control strategies

    SciTech Connect

    Klein, D.E.; Kane, R.L.; Mansueti, L.

    1997-12-31

    Conventional wisdom and much of the public policy debate have usually drawn a clean delineation between acid rain issues and global warming concerns. This traditional approach of evaluating one policy at a time is too simplistic to serve as a framework for electric utilities making major capital investment and fuel procurement decisions to comply with various environmental requirements. Potential Climate change regulation can affect acid rain compliance decisions, and acid rain compliance decisions will affect future GHG emissions. This paper explores two categories of linkages between these different environmental issues. First, the assumptions one makes regarding future climate change policies can have a profound impact on the economic attractiveness of various acid rain compliance strategies. Second, decisions regarding acid rain compliance strategy can have greenhouse gas implications that might prove more or less difficult to address in future climate change legislation.

  19. The acid rain debate. Scientific, economic, and political dimensions

    SciTech Connect

    Yanarella, E.J.

    1985-01-01

    This collection of essays focuses on the political and legal aspects of the acid rain debate, the policy options for resolving the controversy, and the international dimensions of acid rain control. The contributors highlight concerns drawn primarily from the developing study of acid rain in political science, economics, public administration, and policy analysis - concerns that are the focal point of the public debate over the nature, impact, and cost of acid rain and the mitigation of its effects. The book complements the body of research from the natural sciences and responds to the need for applied study to help resolve the current policy stalemate on this environmental issue. The essays are supplemented by a comprehensive annotated bibliography on acid rain and relevant social science research.

  20. Rain rate statistics and fade distributions at 20 and 30 GHz derived from a network of rain gauges in the Mid-Atlantic coast over a five year period

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Krichevsky, Vladimir; Gebo, Norman E.

    1992-01-01

    A network of ten tipping bucket rain gauges located within a grid 70 km north-south and 47 km east-west in the Mid-Atlantic coast of the United States was used to analyze rain rate and modeled slant path attenuation distributions at 20 and 30 GHz. It was shown that, for realistic fade margins at 20 GHz and above, the variable integration times results are adequate to estimate slant path attenuations using models which require 1 min averages. Crane's Global Model was used to derive fade distributions at 20 and 30 GHz.

  1. The politics of markets: The acid rain control policy in the 1990 Clean Air Act amendments

    SciTech Connect

    Kete, N.

    1993-01-01

    This thesis is a review and critique of the development of the acid rain control policy codified as Title IV of the Clean Air Act. The amendments include provisions to address acid rain-air pollution that has been transformed and transported over long distances. Title IV also embodies the first large scale adoption of market principles and economic incentives in the cause of environmental protection. The acid rain control amendments are being hailed as a break with past environmental protection practice and are being offered as a model for further regulatory reform. The thesis looks at the roots of the acid rain policy and considers the set of legal, social, and economic relations embedded in the policy which define the nature of its legal controls over pollution and its inverse, environmental quality. It explores whether the creation of the emissions allowance trading system changes the social relationships that prevailed under the pre-amended Clean Air Act. It responds to and rebuts the concerns of some critics that the policy represents an alienation of the public's right to clean air. A review of the acid rain policymaking process provides a recent and concrete example of the two central concerns inherent in public policy: the making of decisions that establish institutional arrangements, or structures, that both constrain and liberate individual action at the operational level; and the search for the boundary between autonomous behavior and collective decision making. The policy responds to regulatory reform recommendations concerned with improving the effectiveness, accountability, and cost-effectiveness of environmental protection. As a model for future policymaking, the policy goes beyond and encompasses more than the welfare economics ideal of static economic efficiency and the [open quotes]free market environmentalism[close quotes] emphasis on private property and common law.

  2. Atmospheric deposition of {sup 7}Be by rain events, incentral Argentina

    SciTech Connect

    Ayub, J. Juri; Velasco, H.; Rizzotto, M.; Di Gregorio, D. E.; Huck, H.

    2008-08-07

    Beryllium-7 is a natural radionuclide that enters into the ecosystems through wet and dry depositions and has numerous environmental applications in terrestrial and aquatic ecosystems. Atmospheric wet deposition of {sup 7}Be was measured in central Argentina. Rain traps were installed (1 m above ground) and individual rain events have been collected. Rain samples were filtered and analyzed by gamma spectrometry. The gamma counting was undertaken using a 40%-efficient p-type coaxial intrinsic high-purity natural germanium crystal built by Princeton Gamma-Tech. The cryostat was made from electroformed high-purity copper using ultralow-background technology. The detector was surrounded by 50 cm of lead bricks to provide shielding against radioactive background. The detector gamma efficiency was determined using a water solution with known amounts of chemical compounds containing long-lived naturally occurring radioisotopes, {sup 176}Lu, {sup 138}La and {sup 40}K. Due to the geometry of the sample and its position close to the detector, the efficiency points from the {sup 176}Lu decay, had to be corrected for summing effects. The measured samples were 400 ml in size and were counted curing one day. The {sup 7}Be detection limit for the present measurements was as low as 0.2 Bq l{sup -1}. Thirty two rain events were sampled and analyzed (November 2006-May 2007). The measured values show that the events corresponding to low rainfall (<20 mm) are characterized by significantly higher activity concentrations (Bq l{sup -1}). The activity concentration of each individual event varied from 0.8 to 3.5 Bq l{sup -1}, while precipitations varied between 4 and 70 mm. The integrated activity by event of {sup 7}Be was fitted with a model that takes into account the precipitation amount and the elapsed time between two rain events. The integrated activities calculated with this model show a good agreement with experimental values.

  3. Millimeter wave satellite communication studies. Results of the 1981 propagation modeling effort

    NASA Astrophysics Data System (ADS)

    Stutzman, W. L.; Tsolakis, A.; Dishman, W. K.

    1982-12-01

    Theoretical modeling associated with rain effects on millimeter wave propagation is detailed. Three areas of work are discussed. A simple model for prediction of rain attenuation is developed and evaluated. A method for computing scattering from single rain drops is presented. A complete multiple scattering model is described which permits accurate calculation of the effects on dual polarized signals passing through rain.

  4. Millimeter wave satellite communication studies. Results of the 1981 propagation modeling effort

    NASA Technical Reports Server (NTRS)

    Stutzman, W. L.; Tsolakis, A.; Dishman, W. K.

    1982-01-01

    Theoretical modeling associated with rain effects on millimeter wave propagation is detailed. Three areas of work are discussed. A simple model for prediction of rain attenuation is developed and evaluated. A method for computing scattering from single rain drops is presented. A complete multiple scattering model is described which permits accurate calculation of the effects on dual polarized signals passing through rain.

  5. The Evaluation of an improved AMSU rain rate algorithm

    NASA Astrophysics Data System (ADS)

    Qiu, S.; Pellegrino, P.; Ferraro, R.; Zhao, L.

    2003-12-01

    Improvements have been made to the rain rate retrieval from the Advanced Microwave Sounding Units (AMSU). The new features of the improved rain rate algorithm include the two-stream corrections on the satellite brightness temperatures, cloud and rain type classification and removal of the two ad hoc thresholds in the ice water path (IWP) and effective diameter (De) retrieval where the scattering signals are very small. A monthly mean comparison has been made between the improved algorithm and the current NOAA operational algorithm. In addition, comparison with monthly mean rainfall derived from SSMI, TRMM, and GPCP are also conducted in the evaluation. These comparisons indicate that the new algorithm greatly reduces the previous positive bias over ocean, while increases rainfall intensity and picks up more light rain over land. Also, Pacific Atolls rain gauges are used to demonstrate the greatly improved rain rate retrieval over the tropical Pacific ocean. Results of a winter time case study over California from February 2003 further confirm the enhanced ability of the new algorithm in identifying both light and heavy rain over land.

  6. Implications for coronal heating and magnetic field topology from coronal rain observations

    NASA Astrophysics Data System (ADS)

    Antolin, Patrick

    2012-05-01

    -sections along their lengths, multi-stranded and unbraided. Furthermore, a significant fraction of strands in the loops show a coherent thermodynamic evolution, thus imposing several constraints on coronal loop modeling. The mass flux raining down is shown to be significant, as compared to the estimated mass injected into the corona from spicules.

  7. Rainfall estimation from soil moisture data: crash test for SM2RAIN algorithm

    NASA Astrophysics Data System (ADS)

    Brocca, Luca; Albergel, Clement; Massari, Christian; Ciabatta, Luca; Moramarco, Tommaso; de Rosnay, Patricia

    2015-04-01

    Soil moisture governs the partitioning of mass and energy fluxes between the land surface and the atmosphere and, hence, it represents a key variable for many applications in hydrology and earth science. In recent years, it was demonstrated that soil moisture observations from ground and satellite sensors contain important information useful for improving rainfall estimation. Indeed, soil moisture data have been used for correcting rainfall estimates from state-of-the-art satellite sensors (e.g. Crow et al., 2011), and also for improving flood prediction through a dual data assimilation approach (e.g. Massari et al., 2014; Chen et al., 2014). Brocca et al. (2013; 2014) developed a simple algorithm, called SM2RAIN, which allows estimating rainfall directly from soil moisture data. SM2RAIN has been applied successfully to in situ and satellite observations. Specifically, by using three satellite soil moisture products from ASCAT (Advanced SCATterometer), AMSR-E (Advanced Microwave Scanning Radiometer for Earth Observation) and SMOS (Soil Moisture and Ocean Salinity); it was found that the SM2RAIN-derived rainfall products are as accurate as state-of-the-art products, e.g., the real-time version of the TRMM (Tropical Rainfall Measuring Mission) product. Notwithstanding these promising results, a detailed study investigating the physical basis of the SM2RAIN algorithm, its range of applicability and its limitations on a global scale has still to be carried out. In this study, we carried out a crash test for SM2RAIN algorithm on a global scale by performing a synthetic experiment. Specifically, modelled soil moisture data are obtained from HTESSEL model (Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land) forced by ERA-Interim near-surface meteorology. Afterwards, the modelled soil moisture data are used as input into SM2RAIN algorithm for testing weather or not the resulting rainfall estimates are able to reproduce ERA-Interim rainfall data. Correlation, root

  8. The Multithermal and Multi-stranded Nature of Coronal Rain

    NASA Astrophysics Data System (ADS)

    Antolin, P.; Vissers, G.; Pereira, T. M. D.; Rouppe van der Voort, L.; Scullion, E.

    2015-06-01

    We analyze coordinated observations of coronal rain in loops, spanning chromospheric, transition region (TR), and coronal temperatures with sub-arcsecond spatial resolution. Coronal rain is found to be a highly multithermal phenomenon with a high degree of co-spatiality in the multi-wavelength emission. EUV darkening and quasi-periodic intensity variations are found to be strongly correlated with coronal rain showers. Progressive cooling of coronal rain is observed, leading to a height dependence of the emission. A fast-slow two-step catastrophic cooling progression is found, which may reflect the transition to optically thick plasma states. The intermittent and clumpy appearance of coronal rain at coronal heights becomes more continuous and persistent at chromospheric heights just before impact, mainly due to a funnel effect from the observed expansion of the magnetic field. Strong density inhomogeneities of 0\\buildrel{\\prime\\prime}\\over{.} 2-0\\buildrel{\\prime\\prime}\\over{.} 5 are found, in which a transition from temperatures of 105 to 104 K occurs. The 0\\buildrel{\\prime\\prime}\\over{.} 2-0\\buildrel{\\prime\\prime}\\over{.} 8 width of the distribution of coronal rain is found to be independent of temperature. The sharp increase in the number of clumps at the coolest temperatures, especially at higher resolution, suggests that the bulk distribution of the rain remains undetected. Rain clumps appear organized in strands in both chromospheric and TR temperatures. We further find structure reminiscent of the magnetohydrodynamic (MHD) thermal mode (also known as entropy mode), thereby suggesting an important role of thermal instability in shaping the basic loop substructure. Rain core densities are estimated to vary between 2 × 1010 and 2.5× {{10}11} cm-3, leading to significant downward mass fluxes per loop of 1-5 × 109 g s-1, thus suggesting a major role in the chromosphere-corona mass cycle.

  9. Areal rainfall estimation using moving cars as rain gauges - laboratory and field experiment

    NASA Astrophysics Data System (ADS)

    Rabiei, Ehsan; Haberlandt, Uwe; Sester, Monika; Fitzner, Daniel

    2014-05-01

    Areal precipitation estimation for fine temporal and spatial resolution is still a challenging task. Beside the fact that newly developed instrumentations, e.g. weather radar, provide valuable information with high spatial and temporal resolutions, they are subject to different sources of errors. On the other hand, recording rain gauges provide accurate point rainfall depth, but are still often poor in density. Equipping a car with a GPS device as well as sensors measuring rainfall makes it possible to implement cars on the streets as the moving rain gauges. Initial results from a modeling study assuming arbitrary measurement errors have shown that implementing a reasonable large number of inaccurate measurement devices (raincars) provide more reliable areal precipitations compared to the available rain gauge network. The purpose of this study is to derive relationships between sensor readings and rain rate in a laboratory and quantify the errors. Sensor readings involve wiper frequency and optical sensors which are on the cars to automate wiper activities. Besides, the influence of car speed on the sensor readings is investigated implementing a car-speed simulator. It has been observed that the manual wiper activity adjustment, according to front visibility, shows a strong relationship between rainfall intensity and wiper speed. Two optical sensors calibrated in laboratory showed a relatively strong relationship with the rain intensity recorded by a tipping bucket. A positive relationship between the velocity and the amount of water has been observed meaning that the higher the speed of a car, the higher the amount of water hitting the car. Additionally, some preliminary results of the field experiments are discussed.

  10. Understanding the formation and evolution of rain-formed fresh lenses at the ocean surface

    NASA Astrophysics Data System (ADS)

    Drushka, Kyla; Asher, William E.; Ward, Brian; Walesby, Kieran

    2016-04-01

    Rain falling on the ocean produces a layer of buoyant fresher surface water, or "fresh lens." Fresh lenses can have significant impacts on satellite-in situ salinity comparisons and on exchanges between the surface and the bulk mixed layer. However, because these are small, transient features, relatively few observations of fresh lenses have been made. Here the Generalized Ocean Turbulence Model (GOTM) is used to explore the response of the upper few meters of the ocean to rain events. Comparisons with observations from several platforms demonstrate that GOTM can reproduce the main characteristics of rain-formed fresh lenses. Idealized sensitivity tests show that the near-surface vertical salinity gradient within fresh lenses has a linear dependence on rain rate and an inverse dependence on wind speed. Yearlong simulations forced with satellite rainfall and reanalysis atmospheric parameters demonstrate that the mean salinity difference between 0.01 and 5 m, equivalent to the measurement depths of satellite radiometers and Argo floats, is -0.04 psu when averaged over the 20°S-20°N tropical band. However, when averaged regionally, the mean vertical salinity difference exceeds -0.15 psu in the Indo-Pacific warm pool, in the Pacific and Atlantic intertropical convergence zone, and in the South Pacific convergence zone. In most of these regions, salinities measured by the Aquarius satellite instrument have a fresh bias relative to Argo measurements at 5 m depth. These results demonstrate that the fresh bias in Aquarius salinities in rainy, low-wind regions may be caused by the presence of rain-produced fresh lenses.

  11. Using rain-on-snow events to evaluate the quality of bias correction to represent complex inter-variable dependencies

    NASA Astrophysics Data System (ADS)

    Rössler, Ole; Bosshard, Thomas; Weingartner, Rolf

    2016-04-01

    A key issue for adaptation planning is the information of projections about changes of extremes. Climate projections of meteorological extremes and their downscaling are a challenge on their own. Yet - at least in hydrology - meteorological extremes are not necessarily hydrological extremes. These can also result from a sequence of days with only moderate meteorological conditions, too. This sequences are called "storylines". In climate change impact assess studies it is relevant to know, whether these meteorological storylines are represented in regional climate models, and how well can bias correction preserve or improve the representation. One storyline leading to hydrological extremes are rain-on-snow events, and more specifically rain-on-snowfall events. These events challenge the regional climate model and the bias correction in terms of representing absolute values and inter-variable dependences. This study makes use of the rain-on-snow-storylines to evaluate the performance of regional climate models and a bias correction method in reproducing complex inter-variable dependencies. At first, we applied a hydrological model to a mesoscale catchment in Switzerland that is known to be effected by rain-on-snow events. At second, the ERA-Interim driven regional climate model RCA4.5 - developed at SMHI - with a spatial resolution of 0.11 * 0.11 degree was used to drive the hydrological model. At third, bias-correction of the RCM was done applying the distribution based scaling (DBS) bias-correction method (Yang et al., 2010) developed at the SMHI. The bias-corrected data then also served as driving input data to the hydrological model. Based on the simulated runoff, as well as simulated precipitation, temperature, and snow pack data, an algorithm to detect rain-on-snow events was applied. Finally, the presence or absents of rain-on-snow events for the three different climate input data, ERA.RCA4.5, DBS corrected ERA.RC4 and observed climate, are evaluated within

  12. Acid rain reduced in Eastern United States

    SciTech Connect

    Lynch, J.A.; Bowersox, V.C.; Grimm, J.W.

    2000-03-15

    Concentrations of sulfate (SO{sub 4}{sup 2{minus}}) and free hydrogen ions (H{sup +}) in precipitation decreased from 10% to 25% over a large area of the Eastern US from 1995 through 1997 as compared to the previous 12-year (1983--1994) reference period. These decreases were unprecedented in magnitude and spatial extent. In contrast, nitrate (NO{sub 3}{sup {minus}}) concentrations generally did not change over this period. The largest decreases in both H{sup +} and SO{sub 4}{sup 2{minus}} concentrations, which nearly mimicked one another, occurred in and downwind of the Ohio River Valley, the same area where Title 4 of the 1990 Clean Air Act Amendments (CAAA) set limitations on sulfur dioxide (SO{sub 2}) emissions from a large number of utility-owned coal-fired sources. Phase 1 of the CAAA required that these limitations be met by January 1, 1995. On the basis of their analysis of precipitation chemistry and emissions data, the authors conclude that significant declines in acid rain occurred in many parts of the Eastern US from 1995 through 1997 because of large reductions in SO{sub 2} emissions in this region and a corresponding reduction in SO{sub 4}{sup 2{minus}} concentrations in precipitation.

  13. A study of the NOAA 16 AMSU-A brightness temperatures observed over Amazon rain forest

    NASA Astrophysics Data System (ADS)

    Mo, Tsan

    2005-12-01

    Angular distributions of brightness temperatures over the Amazon rain forest observed by the NOAA 16 Advanced Microwave Sounding Unit-A (AMSU-A) window channels are studied and simulated with a radiative transfer model. The model is based on a combination of the atmospheric radiative transfer model and a vegetation canopy model which treats the rain forest as a uniform layer with an effective canopy temperature. Since emission from the ground surface is heavily attenuated by the rain forest canopy, only radiations from the rain forest canopy and the atmospheric medium contribute to the measurements. The measured angular distributions of brightness temperatures at the four window channels 1-3 and 15 (with frequencies centered at 23.8, 31.4, 50.3, and 89 GHz, respectively), have relatively small angular dependence that is attributed to the atmospheric path length since the canopy radiation is angular-independent. Data used in this study are collected from April 2001 to October 2002 for 1 month in each season. Angular distributions of the data from each month show remarkably stable patterns which can be well simulated by the model developed in this study. For the four window channels, ascending (day time 2 PM in the Sun) and descending (nighttime 2 AM in dark) measurements differ by 3-8 K, depending on channels. The root-mean-square (RMS) differences between 2 years' angular distributions for all four channels and the three overlapping months (April, July, and October) are 0.82 K for the ascending passes, and 0.47 K for the descending passes, respectively. The stable pattern and small variation of angular distributions can be potentially useful for postlaunch calibration of future microwave instruments.

  14. 6-hour maximum rain in Friuli Venezia Giulia: Climatology and ECMWF-based forecasts

    NASA Astrophysics Data System (ADS)

    Manzato, Agostino; Cicogna, Andrea; Pucillo, Arturo

    2016-03-01

    Friuli Venezia Giulia (FVG) is a region in Italy with very complex orography, having an annual rainfall amount that varies from about 900 mm on the coast to more than 3200 mm in the Julian Prealps. A network of 104 raingauges placed around the FVG territory was used to extract the absolute maximum rain accumulated every 6 h, during the period 16 February 2006 to 15 February 2015 (9 years). Interannual, annual, weekly and daily cycles of three classes of rain intensities are analyzed, finding that significant rainfalls (MaxRain > 5 mm) are more frequent in the May to mid-August period, while the heaviest rainfalls (> 40 mm) are more probable between May and the beginning of December, with a peak at the very beginning of November. ECMWF 6-h forecasts at 18 gridpoints (spaced at 0.25°) above the FVG region are studied for the same period, to find the maximum 6-h rain forecasted by the ECMWF model from + 6 to + 48 h and correlate it with the observed maximum rain of all the 104 raingauges. It is found that the correlation coefficient R is higher at 0000-0600 UTC and minimum at 1800-0000 UTC, while the BIAS is always negative (underestimation), varying between - 3.5 and - 6.9 mm. Looking at more homogeneous subareas, ECMWF has a much worse BIAS and RMSE for the Prealps zone, while its correlation coefficient is lower for the coastal and plains zones. For comparison, a similar exercise is repeated using a LAM model (ALADIN-ARSO), finding better BIAS and RMSE, but a lower skill for the mean correlation coefficient. Hence, a linear statistical method (multiregression with exhaustive input selection) for forecasting the maximum 6-h rain using as candidate predictors the direct model output (absolute values, anomalies, standardized values, plus mean, max and SD in time and space) is developed independently for four different sub-regions and two periods of the year starting from the ECMWF forecast. It is found that the strong BIAS in the Prealpine area can easily be removed

  15. Characterization of Rain Attenuation and Depolarization at W/V Bands

    DTIC Science & Technology

    2015-07-30

    5. M. Islam, Z. Elabdin, O. Elshaikh, O. Khalifa, A. Zahirul, S. Khan, and A. Naji. “Prediction of Signal Attenuation Due to Dust Storms Using Mie...from a Derived Two-Dimensional Dust Storm Model,” IEEE Trans. Antennas Propagation, Vol. 49, No. 12, pp. 1703-1711, 2001. 7. Study Group 3 – Radiowave...8-12], which causes uncertainty in the correlation of attenuation and rain-rate measurements. Furthermore, the overall dielectric constant of

  16. NASA Sees Heavy Rain in Arabian Sea Tropical Cyclone

    NASA Video Gallery

    On June 29, GPM showed Tropical Cyclone 02A had a few powerful convective thunderstorms southwest of the center of circulation were dropping rain at the extreme rate of over 209 mm (8.2 inches) per...

  17. Soak Up the Rain Ready-to-Use Outreach Tools

    EPA Pesticide Factsheets

    EPA has produced a Soak Up the Rain business card, posters, & a banner that can be downloaded & copied for use by citizens, municipalities, watershed & planning organizations & others in their stormwater/green infrastructure education & outreach efforts.

  18. TRMM Satellite Shows Bertha's Heavy Rain Pushed From Wind Shear

    NASA Video Gallery

    TRMM Satellite Shows Bertha's Heavy Rain Pushed From Wind Shear This 3-D flyby of Tropical Storm Bertha on Aug. 1 was created from TRMM satellite data. It shows (from the south) intense thunderstor...

  19. RAIN: RNA–protein Association and Interaction Networks

    PubMed Central

    Junge, Alexander; Refsgaard, Jan C.; Garde, Christian; Pan, Xiaoyong; Santos, Alberto; Alkan, Ferhat; Anthon, Christian; von Mering, Christian; Workman, Christopher T.; Jensen, Lars Juhl; Gorodkin, Jan

    2017-01-01

    Protein association networks can be inferred from a range of resources including experimental data, literature mining and computational predictions. These types of evidence are emerging for non-coding RNAs (ncRNAs) as well. However, integration of ncRNAs into protein association networks is challenging due to data heterogeneity. Here, we present a database of ncRNA–RNA and ncRNA–protein interactions and its integration with the STRING database of protein–protein interactions. These ncRNA associations cover four organisms and have been established from curated examples, experimental data, interaction predictions and automatic literature mining. RAIN uses an integrative scoring scheme to assign a confidence score to each interaction. We demonstrate that RAIN outperforms the underlying microRNA-target predictions in inferring ncRNA interactions. RAIN can be operated through an easily accessible web interface and all interaction data can be downloaded. Database URL: http://rth.dk/resources/rain PMID:28077569

  20. Heavy Rain Seen in Tropical Depression Ma-on

    NASA Video Gallery

    On Nov. 10, 2016, GPM's radar (Ku Band) found rain falling at a rate of over 198 millimeters (7.8 inches) per hour in an area east of the tropical depression's center. Storm tops of many convective...

  1. Rain Garden Research at EPA's Urban Watershed Research Facility

    EPA Science Inventory

    Rain gardens are vegetated depressions designed to capture and infiltrate stormwater runoff from impervious surfaces such as roofs, parking lots, and roads. The potential benefits compared to traditional curb and gutter drainage systems include peak flow attenuation in receiving...

  2. Rain Garden Research of EPA's Urban Watershed Research Facility (Poster)

    EPA Science Inventory

    Rain gardens are vegetated depressions designed to capture and infiltrate stormwater runoff from impervious surfaces such as roofs, parking lots, and roads. The potential benefits compared to traditional curb and gutter drainage systems include peak flow attenuation in receiving ...

  3. Acid rain on acid soil: a new perspective

    SciTech Connect

    Krug, E.C.; Frink, C.R.

    1983-08-05

    Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and Northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

  4. Acid rain on acid soil: a new perspective

    SciTech Connect

    Krug, E.C.; Frink, C.R.

    1983-08-05

    Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

  5. On the automatic classification of rain patterns on radar images

    NASA Astrophysics Data System (ADS)

    Pawlina Bonati, Apolonia

    The automation of the process of identification and classification of rain patterns on radar derived images is approached using some tools of digital image interpretation adapted to the specific application. The formal characterization of rain patterns and their partition in classes related to the type of precipitation is the main problem addressed in the paper, as the standard well established criteria for such classification are not defined. The digital maps of rain at horizontal plane derived from three-dimensional radar scans are processed by the interpretation package which identifies and classifies rain structures present on the map. The results generated by this package are illustrated in the paper and offered for discussion. The interpretation procedure is tailored for the radio-meteorology applications but the method is adaptable to other field requirements.

  6. Interior view of old rain shed (Building No. 43) showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of old rain shed (Building No. 43) showing truss type A in foreground and truss type B behind that. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  7. View of pipeline carried on a trestle from new rain ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of pipeline carried on a trestle from new rain shed (Building No. 241). Redwood tanks in background. Steel tanks behind trestle. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  8. Rooftop view of old rain shed (Building No. 43), pipeline ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rooftop view of old rain shed (Building No. 43), pipeline on trestle, and water tanks. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  9. Detail of new rain shed (Building No. 241). Note pipeline ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of new rain shed (Building No. 241). Note pipeline connection from collection trough. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  10. Detail of old rain shed (Building No. 43) with gutter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of old rain shed (Building No. 43) with gutter box on northwest side. Maintenance staff in foreground. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  11. 12. Oblique view of northeast facade, showing missing rain gutter, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Oblique view of northeast facade, showing missing rain gutter, deteriorated slate roof, broken windows in tower; view west-northwest, 90mm lens. - Southern Pacific Depot, 559 El Camino Real, San Carlos, San Mateo County, CA

  12. Redwood tanks in foreground with old rain shed (Building No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Redwood tanks in foreground with old rain shed (Building No. 43) and steel tanks in background. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  13. Rooftop view of new rain shed (Building No. 241) showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rooftop view of new rain shed (Building No. 241) showing collection gutter and overhead pipeline. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  14. Interior view of old rain shed (Building No. 43) showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of old rain shed (Building No. 43) showing redwood dry storage building located inside. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  15. Rooftop detail of new rain shed (Building No. 241) with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rooftop detail of new rain shed (Building No. 241) with flume and overhead pipeline. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  16. Detail of old rain shed (Building No. 43) with collection ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of old rain shed (Building No. 43) with collection downspouts from gutter to reservoir. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  17. Redwood tanks with pipeline on trestle passing behind. Old rain ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Redwood tanks with pipeline on trestle passing behind. Old rain shed (Building No. 43) can be seen at right behind the trestle. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  18. New rain shed (Building No. 241) on right with Tanks ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    New rain shed (Building No. 241) on right with Tanks T5, T4 and T2 on left from front to back. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  19. Detail of old rain shed (Building No. 43) showing vertical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of old rain shed (Building No. 43) showing vertical posts on concrete footing with diagonal timber bracing and wire bracing. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  20. New rain shed (Building No. 241), overhead pipeline and raw ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    New rain shed (Building No. 241), overhead pipeline and raw water tank T4. Distribution pump house can be seen at the center of building. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI