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On the maintenance and initiation of the intraseasonal oscillation in the NCEP/NCAR and ECMWF reanalyses and in the GLA and UKMO AMIP simulations

Description: Julian Intraseasonal (Madden-Julian) oscillations are a dominant model of tropical variability (Madden and 1971, 1972). Satellite derived outgoing longwave radiation (OLR) and reanalyses from NCEP/NCAR and ECMWF are used as verification data in a study of intraseasonal variability in the Goddard Laboratory for Atmospheres (GLA) and the United Kingdom Meteorological Office (UKMO) atmospheric general circulation models. Sling0 et al. (1996) indicated that no model was able to capture the dominance of the intraseasonal oscillation (IO) found in the ECMWF/JDP analyses. However, in the case of the GLA and UKMO AMIP integrations, when a clear eastward propagating signal is evident, the period of the oscillation is realistic.Therefore, in order to show the models in their best light, we examine the November-May period during which these models exhibited their strongest&most coherent IO`s. 1987/88 from observations and the reanalyses will be compared with 1986/87 from GLA and 1980/81 from UKMO. Case studies are important since specific processes/mechanisms may be evident which might otherwise be obscured by cornpositing over many years (e.g., Matthews et al. 1996). During the active phase of the IO, convection migrates from the Indian Ocean to the western/central Pacific Ocean, and into the SPCZ. To demonstrate this, we have calculated an IO index to be used for lagged correlation analysis. This pentad averaged time series is constructed from 20-100 day bandpass filtered 200hPa velocity potential over the region 1OO{degrees}- 140{degrees}E, lO{degrees}N- 10{degrees} S from the NCEP/NCAR reanalysis (not shown; the IO index from the ECMWF reanalysis is virtually identical with the NCEP/NCAR IO index [correlation coefficient=0.987]). This region was chosen since this is where the diabatic heating associated with the IO is greatest. This IO index is then correlated with pentad averaged OLR at various time lags. Convection first arises over the western Indian Ocean on day -15. Through day ...
Date: January 1, 1998
Creator: Sperber, K.R.; Slingo, J.M.; Innes, P.M. & Lau, W.K.M.
Partner: UNT Libraries Government Documents Department

Inference of the potential predictability of seasonal land-surface climate from AMIP ensemble integrations

Description: A number of recent studies of the potential predictability of seasonal climate have utilized AGCM ensemble integrations--i.e., experiments where the atmospheric model is driven by the same ocean boundary conditions and radiative forcings, but is started from different initial states. However, only a few variables of direct relevance to the climate of the land surface have been examined. In this study, the authors infer the potential predictability of 11 climate variables that are indicative of the energetics, dynamics, and hydrology of the land surface. They used a T42Ll9 ECMWF (cycle 36) AGCM having a land-surface scheme with prognostic temperature and moisture of 2 layers occupying the topmost 0.50 meters of soil, but with monthly climatological values of these fields prescribed below. Six model realizations of decadal climate (for the period 1979--1988) were considered. In each experiment, the SSTs and sea ice extents were those specified for the Atmospheric Model Intercomparison Project (AMIP), and some radiative parameters were prescribed as well. However, the initial conditions of the model atmosphere and land surface were different: the first two simulations were initialized from ECMWF analyses, while the initial states of subsequent realizations were assigned values that were the same as those at the last time step of the preceding integration.
Date: December 1, 1995
Creator: Phillips, T.J. & Santer, B.D.
Partner: UNT Libraries Government Documents Department

An analysis of US propane markets, winter 1996-1997

Description: In late summer 1996, in response to relatively low inventory levels and tight world oil markets, prices for crude oil, natural gas, and products derived from both began to increase rapidly ahead of the winter heating season. Various government and private sector forecasts indicated the potential for supply shortfalls and sharp price increases, especially in the event of unusually severe winter weather. Following a rapid runup in gasoline prices in the spring of 1996, public concerns were mounting about a possibly similar situation in heating fuels, with potentially more serious consequences. In response to these concerns, the Energy Information Administration (EIA) participated in numerous briefings and meetings with Executive Branch officials, Congressional committee members and staff, State Energy Offices, and consumers. EIA instituted a coordinated series of actions to closely monitor the situation and inform the public. This study constitutes one of those actions: an examination of propane supply, demand, and price developments and trends.
Date: June 1, 1997
Partner: UNT Libraries Government Documents Department

Comparison of the 200 hPa circulation in CSM and CCM3 simulations and NCEP and ERA reanalysis: principal and common principa

Description: In this paper the interannual variation of monthly mean vorticity and divergence at 200 hPa are compared from four data sources: The NCEP/NCAR reanalyses 1958 through 1994, the ECMWF (ERA) reanalyses, 1979 through 1994, a NCAR CCM3 integration using prescribed SSTs from 1979 through 1993, and the NCAR CSM 300 year integration. Four twenty year periods were taken from the 300 year simulation for analysis. The NCEP, ERA and CCM3 all provide data for the period 1979 through1993. The techniques used are principal and common principal component analyses on the fields transformed to spherical harmonics. The seasonal cycle is removed. For the common time period, 1979 through 1994, the ERA, NCEP and CCM3 display a close correspondence for the leading PC of the 200 hPa vorticity.This mode is closely related to the ENSO variations of the period but the agreement extends to the extratropics. All four CSM periods have similar leading modes which are dominated by a PNA type pattern and lack any Equatorial Pacific ENSO patterns. The agreement between the leading PC for the 200 hPa divergence was somewhat less than that of the vorticity. The CCM3 and ERA indicate a larger magnitude center in the Equatorial Pacific about the dateline than NCEP. The CSM has an intense center a 150E. There are indications in the vorticity and divergence fields that this center is at the source for waves propagating to the midlatitudes. Two twenty year periods of the 1958 to 1996 NCEP reanalyses show a distinct difference between the two periods. The variations are comparable in magnitude if not nature to the variations seen amongst the time sections of the CSM run examined. A CPC analysis of the NCEP, ERA and CCM3 show a common ENS0 type response as the leading common component. The models depart from the ...
Date: October 20, 1998
Creator: Boyle, J. S.
Partner: UNT Libraries Government Documents Department

Motor gasoline assessment, Spring 1997

Description: The springs of 1996 and 1997 provide an excellent example of contrasting gasoline market dynamics. In spring 1996, tightening crude oil markets pushed up gasoline prices sharply, adding to the normal seasonal gasoline price increases; however, in spring 1997, crude oil markets loosened and crude oil prices fell, bringing gasoline prices down. This pattern was followed throughout the country except in California. As a result of its unique reformulated gasoline, California prices began to vary significantly from the rest of the country in 1996 and continued to exhibit distinct variations in 1997. In addition to the price contrasts between 1996 and 1997, changes occurred in the way in which gasoline markets were supplied. Low stocks, high refinery utilizations, and high imports persisted through 1996 into summer 1997, but these factors seem to have had little impact on gasoline price spreads relative to average spread.
Date: July 1, 1997
Partner: UNT Libraries Government Documents Department

Dinámica estacional y patrones de distribución de la avifauna asociada a humedales subantárticos en la Reserva de Biosfera Cabo de Hornos (54-55°S), Chile

Description: This article discusses the seasonal dynamics and distribution patterns of birds associated to the sub-Antarctic wetlands in Cape Horn Biosphere Reserve (54-55°S), Chile.
Date: 2009
Creator: Ibarra, J. Tomás; Rozzi, Ricardo, 1960-; Gilabert, Horacio; Anderson, Christopher B.; McGehee, Steven M. & Bonacic, Cristián
Partner: UNT College of Arts and Sciences

The relationship between intraseasonal and interannual variability during the asian summer monsoon

Description: The purpose of this paper is to investigate intraseasonal (30-70 days) and higher frequency (5-30 days) variability and its relationship to interannual variability. Various modelling studies have suggested a link between intraseasonal and interannual variability of the Asian summer monsoon. This relationship has been mainly based upon the similar spatial structures of the dominant EOF patterns of the monsoon circulation on intraseasonal and interannual time scales from simulations with simple models and atmospheric general circulation models. Here we investigate these relationships using 40 years of NCEP/NCAR Reanalysis. Motivation for this study is embodied in the suggestions of Charney and Shukla (1981) that boundary forcing (e.g., sea surface temperature) may predispose the monsoon system towards a dry or wet state, and the result of Palmer (1994), using the Lorenz (1963) model, that the probability of being in one regime of phase space or another is no longer equally probable in the presence of external forcing. To investigate the influence of the boundary forcing, the probability distribution functions (PDF�s) of the principal components are given.
Date: April 21, 1999
Creator: Annamalai, H; Slingo, J M & Sperber, K R
Partner: UNT Libraries Government Documents Department


Description: Four Antech airbath calorimeters at the Hanford site were studied for three summers and two winters in a location not well-shielded from outside temperature changes. All calorimeters showed significant increases in variability of standard measurements during hot weather. The increased variability is postulated to be due to a low setting of the Peltier cold face temperature, which doesn't allow the instrument to drain heat fast enough in a hot environment. A higher setting of the Peltier cold face might lead to better performance in environments subjected to a broad range of temperatures.
Date: April 16, 2007
Creator: CAMERON, M.A.
Partner: UNT Libraries Government Documents Department

Dungeness Crab Dredging Entrainment Studies in the Lower Columbia River, 2002 – 2004: Loss Projections, Salinity Model, and Scenario Analysis

Description: Dungeness crab studies conducted in 2002 for the Portland District of the U.S. Army Corps of Engineers (Corps) constituted a major step forward in quantifying crab entrainment through statistical projections of adult equivalent loss (AEL) and loss to the fishery (LF) from proposed construction and maintenance dredging in the Columbia River navigation channel (Pearson et al. 2002, 2003). These studies also examined the influence of bottom salinity on crab abundance and entrainment rates. Additional sampling was conducted in 2004 to tighten loss projections, further develop the crab salinity model, and apply the model to assess correlations of entrainment rates and projected losses with seasonal salinity changes.
Date: January 1, 2005
Creator: Pearson, Walter H.; Williams, Greg D. & Skalski, John R.
Partner: UNT Libraries Government Documents Department

Evaluation of Steelhead Kelt Passage into the Bonneville Dam Second Powerhouse Corner Collector Prior to the Juvenile Migration Seasons, 2007 and 2008

Description: This report documents the results of a steelhead kelt passage study conducted by the PNNL for the U.S. Army Corps of Engineers at Bonneville Dam in early spring 2007 and 2008. At the Second Powerhouse, a surface flow outlet called the corner collector (B2CC) may be an effective non-turbine passage route for steelhead kelt moving downstream in early spring before the main juvenile emigration season. The goal of this project was to inform management decisions regarding B2CC operations by estimating the number of kelt using the B2CC for downstream passage at Bonneville Dam prior to the juvenile spring migration season. We performed a hydroacoustic study from March 2 to April 10, 2007 and from March 13 to April 15, 2008.
Date: September 1, 2009
Creator: Weiland, Mark A.; Kim, Jina; Nagy, William T. & Johnson, Gary E.
Partner: UNT Libraries Government Documents Department


Description: An in-progress assessment of nutrient chemical data (phosphate, nitrate, nitrite, and silicate) from four potential OTEC sites (Puerto Rico, the Gulf of Mexico, Hawaii, and the South Atlantic) show reasonable comparison with archival data. At this time sufficient data is available only at the Tampa site (Gulf of Mexico) to discern seasonal variations which show an influx of nutrient-rich water in February, which decreases with time to a minimum in December. Results show a greater potential for stimulation of primary productivity at the Hawaii site than in the northern Gulf of Mexico due to the discharge of the cold water pipe into the photic zone.
Date: June 1, 1979
Creator: Quinby-Hung, M.S.
Partner: UNT Libraries Government Documents Department

The UC-LLNL Regional Climate System Model

Description: The UC-LLNL Regional Climate System Model has been under development since 1991. The unique system simulates climate from the global scale down to the watershed catchment scale, and consists of data pre- and post- processors, and four model components. The four model components are (1) a mesoscale atmospheric simulation model, (2) a soil-plant-snow model, (3) a watershed hydrology-riverflow model, and (4) a suite of crop response models. The first three model components have been coupled, and the system includes two-way feedbacks between the soil-plant-snow model and the mesoscale atmospheric simulation model. This three-component version of RCSM has been tested, validated, and successfully used for operational quantitative precipitation forecasts and seasonal water resource studies over the southwestern US. We are currently implementation and validating the fourth component, the Decision Support system for Agrotechnology Transfer (DSSAT). A description of the UC-LLNL RCSM and some recent results are presented.
Date: September 1, 1996
Creator: Miller, N.L. & Kim, Jinwon
Partner: UNT Libraries Government Documents Department

Sensitivity and uncertainty analysis of atmospheric ozone photochemistry models. Final report, September 30, 1993--December 31, 1998

Description: The author has examined the kinetic reliability of ozone model predictions by computing direct first-order sensitivities of model species concentrations to input parameters: S{sub ij} = [dC{sub i}/C{sub i}]/[dk{sub j}/k{sub j}], where C{sub i} is the abundance of species i (e.g., ozone) and k{sub j} is the rate constant of step j (reaction, photolysis, or transport), for localized boxes from the LLNL 2-D diurnally averaged atmospheric model. An ozone sensitivity survey of boxes at altitudes of 10--55 km, 2--62N latitude, for spring, equinox, and winter is presented. Ozone sensitivities are used to evaluate the response of model predictions of ozone to input rate coefficient changes, to propagate laboratory rate uncertainties through the model, and to select processes and regions suited to more precise measurements. By including the local chemical feedbacks, the sensitivities quantify the important roles of oxygen and ozone photolysis, transport from the tropics, and the relation of key catalytic steps and cycles in regulating stratospheric ozone as a function of altitude, latitude, and season. A sensitivity-uncertainty analysis uses the sensitivity coefficients to propagate laboratory error bars in input photochemical parameters and estimate the net model uncertainties of predicted ozone in isolated boxes; it was applied to potential problems in the upper stratospheric ozone budget, and also highlights superior regions for model validation.
Date: March 1, 1999
Creator: Smith, G.P.
Partner: UNT Libraries Government Documents Department

Intercomparison of the seasonal cycle in 200 hPa kinetic energy in AMIP GCM simulations

Description: The 200 hPa kinetic energy is represented by means of the spherical harmonic components for the Atmospheric Model Intercomparison Project (AMIP) simulations, the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and the European Centre for Medium Range Weather Forecast Reanalysis (ERA). The data used are the monthly mean wind fields from 1979 to 1988. The kinetic energy is decomposed into the divergent (DKE) and rotational (RKE) components and emphasis is placed on examining the former. The two reanalysis data sets show reasonable agreement that is best for the rotational kinetic energy. The largest difference in the divergent kinetic energy occurs during the northern summer. As might be expected, the two analyses are closet in regions where there are sufficient observations such that the effect of the model used in the assimilation cycle are minimized. The observed RKE show only a slight seasonal cycle with a maximum occuring during the northern winter. The DKE, on the other hand, has a very pronounced seasonal cycle with maxima at the solsticial seasons and minima during the equinoctial seasons. The model results show a very large spread in the magnitudes of the RKE and DKE although the models all evince a seasonal variation in phase with that observed. The median values of the seasonal cycle of RKE and DKE for the models are usually superior to those of any individual model. Results are also presented for simulation following the AMIP protocol but using updated versions of the original AMIP entries. In most cases these new integrations show better agreement with the observations.
Date: October 1, 1996
Creator: Boyle, J.S.
Partner: UNT Libraries Government Documents Department

Variations of archived static-weight data and WIM

Description: Using seven-card archived, static-weight and weigh-in-motion (WIM), truck data received by FHWA for 1966--1992, the authors examine the fluctuations of four fiducial weight measures reported at weight sites in the 50 states. The reduced 172 MB Class 9 (332000) database was prepared and ordered from 2 CD-ROMS with duplicate records removed. Front-axle weight and gross-vehicle weight (GVW) are combined conceptually by determining the front axle weight in four-quartile GVW categories. The four categories of front axle weight from the four GVW categories are combined in four ways. Three linear combinations are with fixed-coefficient fiducials and one is that optimal linear combination producing the smallest standard deviation to mean value ratio. The best combination gives coefficients of variation of 2--3% for samples of 100 trucks, below the expected accuracy of single-event WIM measurements. Time tracking of data shows some high-variation sites have seasonal variations, or linear variations over the time-ordered samples. Modeling of these effects is very site specific but provides a way to reduce high variations. Some automatic calibration schemes would erroneously remove such seasonal or linear variations were they static effects.
Date: December 1, 1998
Creator: Elliott, C.J.; Gillmann, R. & Kent, P.M.
Partner: UNT Libraries Government Documents Department

Porosity in as-cast U-Al alloy

Description: This memorandum documents a study that showed a cyclic occurrence of porosity in U-Al alloys produced in Building 321-M. Review of process data shows that the extent of porosity is more pronounced in months of warm, humid weather and less pronounced in cooler, drier months. This porosity is most likely caused by hydrogen, which becomes dissolved in the molten U-Al alloy during casting. Although excessive porosity was the cause of some observed process anomalies, this type of porosity has no significant effect on yield or fuel tube quality.
Date: February 25, 1988
Creator: Rhode, F. C.
Partner: UNT Libraries Government Documents Department

Geobotanical and lineament analysis of sandsat satellite imagery for hydrocarbon microseeps

Description: Both geobotanical and structural interpretations of remotely sensed data tend to be plagued by random associations. However, a combination of these methods has the potential to provide a methodology for excluding many false associations. To test this approach, a test site in West Virginia has been studied using remotely sensed and field data. The historic Volcano Oil Field, in Wood, Pleasants and Ritchie Counties was known as an area of hydrocarbon seeps in the last century. Although pressures in the reservoir are much reduced today, hydrocarbons remain in the reservoir. An examination of a multi-seasonal Landsat Thematic Mapper imagery has shown little difference between the forests overlying the hydrocarbon reservoirs compared to the background areas, with the exception of an image in the very early fall. This image has been enhanced using an nPDF spectral transformation that maximizes the contrast between the anomalous and background areas. A field survey of soil gas chemistry showed that hydrocarbon concentration is generally higher over the anomalous region. In addition, soil gas hydrocarbon concentration increases with proximity to linear features that cross the strike of the overall structure of the reservoir. Linear features that parallel the strike, however, do not have any discernible influence on gas concentration. Field spectral measurements were made periodically through the summer and early fall to investigate the origin of the spectral reflectance anomaly. Measurements were made with a full-range spectro-radiometer (400 nm to 2500 nm) on a number of different species, both on and off the spectral anomaly. The results lend support to the finding that in the early fall spectral reflectance increases in the near infrared and mid infrared in the spectrally anomalous regions.
Date: October 1, 1997
Creator: Warner, T.A.
Partner: UNT Libraries Government Documents Department

Interannual variation of East Asian Winter Monsoon and ENSO

Description: This paper examines the interannual variation of the East Asian winter monsoon and its relationship with EJSO based on the 1979-1995 NCEP/NCAR reanalysis. Two stratifications of cold surges are used. The first one, described as the conventional cold surges, indicates that the surge frequency reaches a urn one year after El Nino events. The second one, originated from the same region as the first, is defined as the maximum wind events near the South China Sea. The variation of this stratification of surges is found to be in good agreement with the South Oscillation Index (SOI). Low SOI (high SOI) events coincide with years of low (high) surge frequency. The interannual variation of averaged meridional wind near the South China Sea and western Pacific is dominated by the South China Sea cold surges, and is also well correlated (R--O.82) with the SOI. Strong wind seasons are associated with La Nina and high SOI events; likewise, weak wind years are linked with El Nino and low SOI cases. This pattern is restricted north of the equator within the region of (OON-20 N, 11OOE-1300E), and is confined to the near surface layer. The surface Siberian high, 500 hPa trough and 200 hPa jetstream, all representing the large-scale monsoon flow, are found to be weaker than normal during El Nino years. In particular, the interannual variation of the Siberian high is in general agreement with the SOL.
Date: December 1, 1996
Creator: Zhang, Yi; Sperber, Kenneth R. & Boyle, James S.
Partner: UNT Libraries Government Documents Department

Annual and seasonal global temperature anomalies in the troposphere and low stratosphere, 1958 - Summer 1986

Description: Surface temperatures and thickness-derived temperatures from a network of 63 well-distributed radiosonde stations have been used to estimate global and zonal annual and seasonal temperatures anomalies for the period 1958 through the summer of 1986. These anomaly estimates were made using a 1958-1977 reference period mean. Anomaly estimates are provided for surface, troposphere (850-300 mb), tropopause layer (300-100 mb), and low stratosphere (100-50 mb); (100-30mb) layers and for polar (60{degrees}-90{degrees}), temperate (30{degrees}-60{degrees}), subtropical (10{degrees}-30{degrees}), and equatorial (10{degrees}N - 10{degrees}S) zones, as well as the tropics, both hemispheres, and the world.
Date: April 1, 1987
Creator: Angell, J.K.; Korshover, J. & Boden, T.A.
Partner: UNT Libraries Government Documents Department

Alternative measures of potential predictability applied to ensemble simulations of seasonal land-surface climate

Description: The potential predictability (PP) of seasonal climate at the land surface is of enormous human import, and therefore merits close investigation. The PP of a seasonal land-surface variable may be defined as the upper bound in mean forecast to be expected when the seasonal state of the oceans is known precisely (as when SST`s are prescribed), but when the initial conditions are known imprecisely. The PP of a seasonal land-surface variable is related to its degree of insensitivity to the choice of initial conditions when the ocean boundary conditions are invariant. There are various ways of measuring this initial-condition insensitivity, two of which are utilized here. The PP of a seasonal mean variable can be estimated from an ensemble of repeated simulations of a mul period in which the ocean boundary conditions are the same, but in which the initial conditions of the model`s land/atmosphere system are different. It should be noted that a truly accurate determination of PP following this approach requires use of a perfect model. Estimates of PP made with current generation models there fore must be regarded as quite imprecise.
Date: December 1, 1996
Creator: Phillips, T.J.
Partner: UNT Libraries Government Documents Department

On the predictability of the interannual behaviour of the Madden-Julian oscillation and its relationship with El Nino

Description: The Madden-Julian Oscillation (MJO) is the dominant mode of tropical variability at intraseasonal timescales. It displays substantial interannual variability in intensity which may have important implications for the predictability of the coupled system. The reasons for this interannual variability are not understood. The aim of this paper is to investigate whether the interannual behavior of the MJO is related to tropical sea surface temperature (SST) anomalies, particularly El Nino, and hence whether it is predictable. The interannual behavior of the MJO has been diagnosed initially in the 40-year NCEP/ NCAR Reanalysis. The results suggest that prior to the mid-1970s the activity of the MJO was consistently lower than during the latter part of the record. This may be related to either inadequacies in the data coverage, particularly over the tropical Indian Ocean prior to the introduction of satellite observations, or to the real effects of a decadal timescale warming in the tropical SSTs. The teleconnection patterns between interannual variations in MJO activity and SST show only a weak, barely significant, influence of El Nino in which the MJO is more active during the cold phase. As well as the NCEP/NCAR Reanalysis, a 4-member ensemble of 45 year integrations with the Hadley Centre climate model (HadAM2a), forced by observed SSTs for 1949-93, has been used to investigate the relationship between MJO activity and SST. HadAM2a is known to give a reasonable simulation of the MJO and the extended record provided by this ensemble of integrations allows a more robust investigation of the predictability of MJO activity than was possible with the 40-year NCEP/NCAR Reanalysis. The results have shown that, for the uncoupled system, with the atmosphere being driven by imposed SSTS, there is no reproducibility for the activity of the MJO from year to year. The interannual behavior of the MJO ...
Date: March 1, 1998
Creator: Sperber, K.R., LLNL
Partner: UNT Libraries Government Documents Department

Dynamical seasonal predictability of the Asian summer monsoon

Description: The goals of this paper are to (1) ascertain the ability of atmospheric general circulation models to hindcast the summer monsoons of 1987, 1988, and 1993, (2) to determine how well the models represent the dominant modes of subseasonal variability of the 850hPa flow, (3) to determine if the models can represent the strong link between the subseasonal modes of variability and the rainfall, (4) to determine if the models properly project these modes onto interannual timescales, (5) to determine if it is possible to objectively discriminate among the ensemble members to ascertain which members are most reliable. The results presented here are based upon contributions to the seasonal prediction model intercomparison project (SMIP), which was initiated by the CLIVAR Working Group on Seasonal to Interannual Prediction (WGSIP; formally Numerical Experimentation Group-1). For each summer, June--September, ensembles of integrations were performed using observed initial conditions, and observed sea surface temperatures. Here, the results from a 4-member ensemble from the United Kingdom Met Office (UKMO) model are presented for the sake of brevity. The conclusions based on the analysis of this model are consistent with the behavior of the other models.
Date: December 14, 1999
Creator: Sperber, K R
Partner: UNT Libraries Government Documents Department