Peer Reviewed Journal Articles by Nicholas R Nalli
Optics Continuum, 2022
This paper describes a data archaeology and rescue of temperature-dependent thermal infrared (IR)... more This paper describes a data archaeology and rescue of temperature-dependent thermal infrared (IR) optical constants for liquid water from previously published works. The data rescue is based upon digitization of a figure published by Pinkley et al. [J. Opt. Soc. Am. 67, 494 (1977)], which showed ratios of laboratory measured spectral reflectances taken at 4 different temperatures (1, 16, 39, and 50°C) with those measured previously at 27°C. Using our digitization of these data, we perform Kramers-Kronig analyses to derive temperature-dependent optical constants for existing standard datasets taken at room temperatures for the entire thermal IR spectrum. These datasets are of interest for the accurate modeling of thermal IR surface emissivity and reflectance over the range of global surface temperatures.
Remote Sensing, 2020
This paper provides an overview of the validation of National Oceanic and Atmospheric Administrat... more This paper provides an overview of the validation of National Oceanic and Atmospheric Administration (NOAA) operational retrievals of atmospheric carbon trace gas profiles, specifically carbon monoxide (CO), methane (CH 4) and carbon dioxide (CO 2), from the NOAA-Unique Combined Atmospheric Processing System (NUCAPS), a NOAA enterprise algorithm that retrieves atmospheric profile environmental data records (EDRs) under global non-precipitating (clear to partly cloudy) conditions. Vertical information about atmospheric trace gases is obtained from the Cross-track Infrared Sounder (CrIS), an infrared Fourier transform spectrometer that measures high resolution Earth radiance spectra from NOAA operational low earth orbit (LEO) satellites, including the Suomi National Polar-orbiting Partnership (SNPP) and follow-on Joint Polar Satellite System (JPSS) series beginning with NOAA-20. The NUCAPS CO, CH 4 , and CO 2 profile EDRs are rigorously validated in this paper using well-established independent truth datasets, namely total column data from ground-based Total Carbon Column Observing Network (TCCON) sites, and in situ vertical profile data obtained from aircraft and balloon platforms via the NASA Atmospheric Tomography (ATom) mission and NOAA AirCore sampler, respectively. Statistical analyses using these datasets demonstrate that the NUCAPS carbon gas profile EDRs generally meet JPSS Level 1 global performance requirements, with the absolute accuracy and precision of CO 5% and 15%, respectively, in layers where CrIS has vertical sensitivity; CH 4 and CO 2 product accuracies are both found to be within ±1%, with precisions of ≈1.5% and 0.5%, respectively, throughout the tropospheric column.
Secrets of a Homicide - John F. Kennedy Assassination News, Commentary, and Opinion, 2021
Critical Review of Last Second in Dallas (2021) by Josiah Thompson.
(University Press of Kansas,... more Critical Review of Last Second in Dallas (2021) by Josiah Thompson.
(University Press of Kansas, ku.edu, 504 pp., $29.95, Last Second in Dallas)
Includes a technical review summarizing the scientific invalidation of the DPD radio recordings as "acoustics evidence," including:
1. Timing issues.
2. Open mic location assumptions.
3. Insufficient information-content within the DPD recordings.
The article concludes with a photogrammetric analysis of Zapruder Film Frames #312 and #313, demonstrating that the forward motion of President Kennedy's head was in fact a real motion consistent only with a shot from behind.
J. Assoc. Crime Scene Reconstr., 2018
US President John F. Kennedy was assassinated by a sniper while riding in an open limousine in Da... more US President John F. Kennedy was assassinated by a sniper while riding in an open limousine in Dallas, Texas on 22 November 1963. Although official investigations established that three shots were fired from a sniper’s nest in the Texas School Book Depository, a complete reconstruction of the sequence of shots was not thoroughly established. Subsequent research has led to a consensus that the first shot missed, but a complete explanation has eluded investigators. This paper presents a quantitative analysis of the sniper targeting effort, including the advantages of the sniper’s nest and eventual marksmanship difficulty. It is quantitatively shown that the three-dimensional target tracking was significantly reduced as the motorcade proceeded away from the sniper’s nest. The reduction in apparent motion of the target correlates with the increasing accuracy of the three shots, suggesting this variable plausibly factored into the enigmatic hit-and-miss pattern.
Heliyon, 2018
U.S. President John F. Kennedy was assassinated while riding in an open motorcade by a sniper in ... more U.S. President John F. Kennedy was assassinated while riding in an open motorcade by a sniper in Dallas, Texas on 22 November 1963. A civilian bystander, Mr. Abraham Zapruder, filmed the motorcade with a 8-mm home movie camera as it drove through Dealey Plaza, inadvertently recording an ≈8 second sequence of events that included a fatal gunshot wound to the President in the head. The accompanying backward motion of the President's head after impact appeared to support later " conspiracy theories " because it was claimed that this was proof of a shot from the front (in addition to one from behind). In this paper, simple one-dimensional dynamical models are uniquely applied to study in detail the fatal shot and the motion of the President's head observed in the film. Using known parameters from the crime scene, explicit force calculations are carried out for determining the projectile's retardation during tissue passage along with the resulting transfer of momentum and kinetic energy (KE). The computed instantaneous KE transfer within the soft tissue is found to be consistent with the formation of a temporary cavity associated with the observed explosion of the head, and subsequent quantitative examination of this phenomenon reveals two delayed forces at play in the backward motion of the President following impact. It is therefore found that the observed motions of President Kennedy in the film are physically consistent with a high-speed projectile impact from the rear of the motorcade, these resulting from an instantaneous forward impulse force, followed by delayed rearward recoil and neuromuscular forces.
Bulletin of the American Meteorological Society, 2011
Applied Optics, 2008
Although published sea surface infrared (IR) emissivity models have gained widespread acceptance ... more Although published sea surface infrared (IR) emissivity models have gained widespread acceptance for remote sensing applications, discrepancies have been identified against field observations obtained from IR Fourier transform spectrometers at view angles ≳40°. We therefore propose, in this two-part paper, an alternative approach for calculating surface-leaving IR radiance that treats both emissivity and atmospheric reflection in a systematic yet practical manner. This first part presents the theoretical basis, development, and computations of the proposed model.
Applied Optics, 2008
The surface-leaving radiance model developed in Part I [Appl. Opt. 47, 3701 (2008)] is validated ... more The surface-leaving radiance model developed in Part I [Appl. Opt. 47, 3701 (2008)] is validated against an exhaustive set of Fourier transform spectrometer field observations acquired at sea. Unlike prior limited studies, these data include varying all-sky atmospheric conditions (clear, cloudy, and dusty), with regional samples from the tropics, mid-latitudes, and high latitudes. Our analyses show the model to have reduced bias over standard models at emission angles ≳45°.
Applied Optics, 2001
A numerical model is developed for computation of the reflection of atmospheric-emitted IR radian... more A numerical model is developed for computation of the reflection of atmospheric-emitted IR radiance from a wind-roughened water body. The model assumes the Kirchhoff approximation for rough surface scattering. This allows application of the postulates of geometrical optics to determine the reflection of rays from an ensemble of wave facets. We performed the hemispherical integration with Gaussian quadrature by using an uplooking fast transmittance model. This calculation is simplified further through the concept of a reflection-diffusivity angle. The model compares favorably with observed radiance spectra obtained from the Marine-Atmospheric Emitted Radiance Interferometer during the Combined Sensor Program research cruise.
Journal of Geophysical Research: Atmospheres, 2013
Journal of Geophysical Research: Atmospheres, 2012
1] Accurate environmental satellite observations and calculations of top-of-atmosphere infrared (... more 1] Accurate environmental satellite observations and calculations of top-of-atmosphere infrared (IR) spectral radiances are required for the accurate retrieval of environmental data records (EDRs), including atmospheric vertical temperature and moisture profiles. For this reason it is important that systematic differences between observations and calculations under well-characterized conditions be minimal, and because most sensors must scan the earth surface to facilitate global coverage, this should include unbiased agreement over the range of zenith angles encountered. This paper investigates the "clear-sky observations" commonly used in such analyses, which include "cloud-masked" data (as is typical from imagers), as well as "cloud-cleared radiances" (as is typical from hyper/ultraspectral sounders). Here we derive simple physical conceptual models to examine quantitatively the longwave IR brightness temperature sensitivity arising from the increasing probability of cloudy fields-of-view with zenith angle, or alternatively from increased slant-path through an aerosol layer. To model the angular effect of clouds, we apply previously derived probability of clear line-of-sight (PCLoS) models for single-layer broken opaque clouds. We then generalize this approach to account for the impact of high, semitransparent (non-opaque) cold clouds, by deriving analytical expressions for the mean slant-paths through each of the idealized shapes under consideration. Our sensitivity analyses suggest that contamination by residual clouds and/or aerosols within clear-sky observations can have a measurable concave-up impact (i.e., an increasing positive bias symmetric over the scanning range) on the angular agreement of hypothetical "observations" with "calculations." The magnitudes are typically on the order of couple tenths of a Kelvin or more depending on the residual absolute cloud fraction and optical depth (i.e., the degree of cloud contamination), the residual aerosol optical depth (i.e., the degree of aerosol contamination), the temperature difference between the surface and the residual cloud/aerosol layers, and the shape and vertical aspect ratio of the clouds. Citation: Nalli, N. R., C. D. Barnet, E. S. Maddy, and A. Gambacorta (2012), On the angular effect of residual clouds and aerosols in clear-sky infrared window radiance observations: Sensitivity analyses,
Journal of Geophysical Research, 2002
1] This research presents the first-phase derivation and implementation of daytime aerosol correc... more 1] This research presents the first-phase derivation and implementation of daytime aerosol correction algorithms for remotely sensed sea surface temperature (SST) from the advanced very high resolution radiometer (AVHRR) instrument flown onboard NOAA polar orbiting satellites. To accomplish this, a long-term (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998), global AVHRRbuoy match-up database was created by merging the NOAA/NASA Pathfinder Atmospheres and Pathfinder Oceans data sets. The merged data set is unique in that it includes daytime estimates of aerosol optical depth (AOD) derived from AVHRR channel 1 (0.63 mm) under global conditions of significant aerosol loading. Histograms of retrieved AOD reveal monomodal, lognormal distributions for both tropospheric and stratospheric aerosol modes. It is then shown empirically that the SST depression caused under each aerosol mode can be expressed as a linear function in two predictors, these being the slant path AOD retrieved from AVHRR channel 1 along with the ratio of channels 1 and 2 normalized reflectances. On the basis of these relationships, parametric equations are derived to provide an aerosol correction for retrievals from the daytime NOAA operational multichannel and nonlinear SST algorithms. Separate sets of coefficients are utilized for two aerosol modes: tropospheric (i.e., dust, smoke, haze) and stratospheric/tropospheric (i.e., following a major volcanic eruption). The equations are shown to significantly reduce retrieved SST bias using an independent set of match-ups. Eliminating aerosolinduced bias in both real-time and retrospective processing will enhance the utility of the AVHRR SST for the general user community and in climate research. Citation: Nalli, N. R., and L. L. Stowe, Aerosol correction for remotely sensed sea surface temperatures from the National Oceanic and Atmospheric Administration advanced very high resolution radiometer,
Aerosol Retrievals from the Multiyear Multisatellite AVHRR Pathfinder Atmosphere (PATMOS) Dataset for Correcting Remotely Sensed Sea Surface Temperatures
Journal of Atmospheric and Oceanic Technology, 2002
Geophysical Research Letters, 2005
Geophysical Research Letters, 2005
Retrieval of Ocean and Lake Surface Temperatures from Hyperspectral Radiance Observations
Journal of Atmospheric and Oceanic Technology, 2003
... For lake surfaces, the refractive indices of pure water are used, whereas for ocean surfaces ... more ... For lake surfaces, the refractive indices of pure water are used, whereas for ocean surfaces a salinity correction is applied (see Nalli et al. 2001). ... Multispectral retrievals could therefore benefit from a priori information about the atmospheric condition (eg, Steyn-Ross et al. ...
Improved remote sensing of sea surface skin temperature using a physical retrieval method
Journal of Geophysical Research, 1998
A new physically based method for retrieving sea surface skin tempera- ture (SST) from satellite ... more A new physically based method for retrieving sea surface skin tempera- ture (SST) from satellite measurements of upwelling infrared radiance is developed. The method accounts for atmospheric interference by utilizing multispectral win- dow information to explicitly solve the radiative transfer equation. Two essential elements are required for this SST retrieval: (1) a priori specification of sea sur- face emissivity and reflectivity spectra and (2) atmospheric transmittances that accurately portray the relative spectral dependence of molecular absorption. The algorithm can be directly applied to any multispectral instrument (e.g., the NOAA advanced very high resolution radiometer and/or the ERS-1 along track scanning radiometer), as well as high resolution spectrometers such as the University of Wisconsin high-resolution interferometer sounder (HIS). Error analyses have shown that SST can theoretically be retrieved to within 0.22 K RMS using high spectral resolution data (or approximately 0.51 K RMS using broadband split-window data) provided that the a priori surface emissivity spectrum does not deviate by more than 0.005 from the true surface emissivity. High spectral resolution has distinct advantages in reducing the effects of atmospheric absorption and instrumental noise errors, as well as providing better guess atmospheric profiles for the transmittance calculations. Application of the method to HIS radiance data acquired from high- altitude aircraft during the 1993 Convection and Moisture Experiment and 1995 Ocean Temperature Interferometric Survey suggests the possibility of physical re- trieval of SST from future satellite remote sensing systems (e.g., the EOS advanced infrared sounder) with accuracies limited primarily by detector performance.
Journal of Geophysical Research, 2006
Journal of Geophysical Research, 2006
Bulletin of the American Meteorological Society, 1996
Uploads
Peer Reviewed Journal Articles by Nicholas R Nalli
(University Press of Kansas, ku.edu, 504 pp., $29.95, Last Second in Dallas)
Includes a technical review summarizing the scientific invalidation of the DPD radio recordings as "acoustics evidence," including:
1. Timing issues.
2. Open mic location assumptions.
3. Insufficient information-content within the DPD recordings.
The article concludes with a photogrammetric analysis of Zapruder Film Frames #312 and #313, demonstrating that the forward motion of President Kennedy's head was in fact a real motion consistent only with a shot from behind.