bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Near-IR Light Source for Eye-Safe Lidar Applications [1]
Authors: Singh U. N. , Chu Z. , Wilkerson T. D.
Published: February 2023

The most commonly used lidar (light detection and ranging) systems are not eye-safe and pose potential risk of eye damage especially in the case of downward pointing airborne lidar systems. A short wavelength lidar capable of operating in nominally eye-safe spectral regions (1.54 μm) is needed for cloud and aerosol studies [2, 3]. A Raman-shifted Nd:YAG laser capable of generating 1.54 μm radiation can be developed to qualify as an eye-safe lidar [4,5,6]. The eye-safety criterion set by the American National Standard Institute (ANSI) for a single pulse exposure is: 1 J/cm2 at 1.54 μm, which is specified to be about 400,000 times safer, for eye exposure, than Nd:YAG laser radiation at 1.06 μm [4].
Eye-Safe 2.1 μm Ho Lidar for Measuring Atmospheric Aerosols and Water Vapor
Authors: Sugimoto Nobuo , Cha Sungdo , Chan Kinpui , Killinger Dennis K.
Published: February 2023

A direct-detection eye-safe Ho Lidar has been developed for atmospheric aerosol profiling and differential absorption measurements of water vapor.
Water Vapor Spectroscopic Data for Lidar Water Vapor Measurements in the 720-nm Wavelength Region
Authors: Grossmann Benoist E. , Browell Edward V.
Published: February 2023

The Differential Absorption Lidar (DIAL) technique can be used to remotely measure profiles of atmospheric gases such as water vapor. The application of this technique requires accurate water vapor spectroscopic data on line strength, pressure broadening, pressure shifts, and linewidth temperature dependence in the wavelength region of interest. As part of NASA's atmospheric research program, the NASA Langley Research Center is currently involved in developing a DIAL system for the Lidar Atmospheric Sensing Experiment (LASE)(1). This DIAL system will use tunable Alexandrite lasers and operate from a high-altitude ER-2 (extended range U-2) aircraft for the measurement of tropospheric water vapor distributions. To support this experiment, a high- resolution spectroscopy setup consisting of a cw ring dye laser and two White cells was used to provide measurements of needed water vapor line parameters. Measurements were made of the absorption line strength, width, and pressure shift in air, and the temperature dependence of linewidth and shift for 270 absorption lines lying between 717 and 738 nm. The line shapes were also studied, and deviations from the standard Voigt profile were found resulting from the Dicke-narrowing effect. In addition, linewidths and shifts have been investigated in various buffer gases including nitrogen, oxygen, argon, and xenon.
A Comparison of Avhrr Radiances with Airborne Radiometer Measurements
Authors: Griffin Vanessa L. , Newchurch Michael J.
Published: February 2023

A comparative study determined the ability to predict line-of-sight aircraft infrared radiance measurements using multispectral radiances derived from the AVHRR.
An Overview of LAS/ILAS
Authors: Matsuzaki A.
Published: February 2023

The Limb-Atmospheric Infrared Spectrometer (LAS) was launched on February 14, 1984, boarding on the satellite "OHZORA" (EXOS-C) to investigate the constituents of the middle atmosphere. This sensor measures the infrared spectra of the solar radiation passing a limb atmosphere at various tangent heights. These spectra include the "whole" absorption bands of water vapor, carbon dioxide, methane, ozone, and nitrous oxide. Furthermore the spectra give the wavelength dependence of the aerosol scattering extinction. Consequently, we can get the vertical profiles of these atmospheric constituents at various global points, with good accuracy.
Comparison of Re-calibrated TOMS Total Ozone Data with Dobson Network
Authors: Wellemeyer Charles G. , Singh Ramdas R. , McPeters Richard D. , Hudson Robert D.
Published: February 2023

Nine years of reprocessed Version 6 total ozone data from the Total Ozone Mapping Spectrometer (TOMS) are compared with selected subsets of the Dobson ground based Network. A small long-term drift of -0.11 ± 0.09 %/yr (95% confidence) is identified in the first nine years of TOMS data relative to Dobson. This small change in bias (amounting to 1% over the nine year period) is of the order of the long-term stability of the calibration of both measurement systems. However, a possible mechanism for the drift is identified. Changes in tropospheric ozone are only partly measured by the backscattered ultraviolet (BUV) method [Klenk et al., 1982]. Based on recent estimates of the change in tropospheric ozone [Bojkov, 1987] and of the BUV sensitivity to changes in tropospheric ozone [Fleig et al., 1989], about half of the observed drift would be attributed to this effect. The reprocessed Version 6 TOMS data set is available through the National Space Science Data Center, GSFC/NASA, Greenbelt Maryland.
Table Mountain Ozone Intercomparison: Brewer Ozone Spectrophotometer Total Column Measurements
Authors: Kerr J.B. , McElroy C.T.
Published: February 2023

The Canadian Atmospheric Environment Service (AES) operated a Brewer ozone spectrophotometer during the Stratospheric Ozone Intercomparison Campaign (STOIC) at Table Mountain Observatory from July 19 to August 2, 1989. Direct sun measurements of total column ozone and measurements of the ozone profile using the umkehr technique were made throughout the 2 weeks of the intercomparison. Results of the total ozone measurements made during the intercomparison are presented herein. Results of the umkehr measurements are given by McElroy and Kerr, this issue.
Advances in the Hitran Spectroscopic Database For Remote Sensing
Authors: Rothman Laurence S.
Published: February 2023

The spectroscopic molecular database, HITRAN, has been periodically updated since its inception in 1973, increasing in spectral coverage from the microwave through the visible, incorporating more molecular species and bands, and adding more transition parameters. HITRAN has gone from about 100,000 transitions in the first edition to well over a third of a million in the last edition of November 19861 and also includes cross-section data on heavy molecular species such as the CFC's and oxides of nitrogen. This database has been used for a very broad range of applications such as laser propagation, detection of hot sources, background characterization, remote sensing of atmospheric constituents, development of band models, pollution studies, climate mechanisms, the greenhouse effect, and has a major impact as the foundation for radiation computer models. The desirability of having such a database as an open reference has promoted the free flow of data and calculations throughout the world to enhance the usefulness of this project to the world community. Over the years numerous ad hoc as well as specific meetings have been held that focussed on the issue of the molecular spectroscopic database. Most recently a two day workshop was held at AFGL that reviewed the status of relevant new data, establishment of priorities for inclusion of data, and discussion of issues involving the archiving of the burgeoning amount of data to take advantage of new technology and also to provide users with the optimum ease in their applications. Of the many significant improvements to HITRAN, the development of new carbon dioxide line parameters will have a substantial impact on remote sensing.
Improved Absorption Cross Sections for the Retrieval of Nimbus 7 LIMS Water Vapor
Authors: Remsberg Ellis E.
Published: February 2023

Distributions of stratospheric water vapor from the Nimbus 7 LIMS experiment have been reported in the literature (WMO, 1986; Russell, 1987; Remsberg et al., 1989) and used for scientific study (e.g. Jones et al., 1986; Hansen and Robinson, 1989). In general, the picture that has emerged is consistent with the mechanisms believed to be controlling water vapor there--namely, the transport of near-saturated air upward through the tropical tropopause and then poleward, plus the process of "methane oxidation," which produces water vapor primarily in the upper stratosphere. Russell et al. (1984) and Remsberg et al. (1984) previously reviewed both the theoretical estimates of error as well as differences with in situ measurements of water vapor obtained at approximately the same time and location as a LIMS measurement. Their reported estimated accuracy of the LIMS water vapor data for single profiles is of the order of 20 percent from 30 to 3 mb over most regions, decreasing to 30 percent at 1 mb and 38 percent at 70 mb. Systematic errors associated with uncertainties in the absorption cross sections near 6.9 μm for H2O, CH4, and O2 are updated in this paper based on improvements that have been made available since the LIMS data were processed.
Critical Reflectance
Authors: Kim Hongsuk H.
Published: February 2023

In previous works, a model which relates intensities to ground reflectance and aerosol scattering phase function was introduced as it is stored in the form of a simplified 3 by 3 matrix 1). And in a subsequent study, several atmospheres, in a range of optical thicknesses, were applied in search of a best fit model for a Landsat scene 2). In this paper, further refinement of the methodology to infer an optical thickness parameter, τ(Mie), by the use of "the critical reflectance " is discussed.
High Speed Photon Counting Lidar
Authors: Lentz W.J.
Published: February 2023

Very high speed photon counting combined with semiconductor lasers allows the construction of eyesafe visibility and ceiling lidar operating in the presence of bright clouds.
Optical Remote Sensing of Wind and Turbulence using Double Spatial Filtering of Scintillations
Authors: Chumside James H. , Hanson Steen G. , Clifford Steven F.
Published: February 2023

Using a spatially filtered optical transmitter and a spatially filtered optical receiver, one can measure transverse wind velocity and also the strength of refractive turbulence at some localized region of the atmosphere along the propagation path from the transmitter to the receiver[1-3]. A profile of either quantity along the path can be obtained by using various combinations of filters. However, this technique requires a spatial filter on each side of the volume to be measured. For some applications, such as vertical profiling of the atmosphere, it would be desirable to place both filters at the receiver end of the path. The source could then be a natural source such as the sun or a star. In fact, this can be done.
Sciamachy Instrument Development
Authors: Goede A.P.H. , Burrows J.P. , Smorenburg C. , Visser H. , de Vries J.
Published: February 2023

SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) is an optical imaging spectrometer for atmospheric chemistry research [1.2]. The instrument is selected by ESA to fly on POEM-1 (Polar Orbiting Earth observation Mission) scheduled for launch in 1997/8. Also it has been selected by DARA to fly on ATMOS scheduled for 1996. The instrument is presently in its phase B development stage.
High Spectral Resolution Sounding with the Atmospheric Infrared Sounder (AIRS)
Authors: Chahine Moustafa T.
Published: February 2023

AIRS is a high spectral resolution instrument consisting of two pupil imaging, multi-aperture grating spectrometers which provide contiguous spectral coverage from 3.4 to 15.4 μm, corresponding to 649 - 2941 cm-1, at a resolving power of 1200. The short-wave spectrometer covers 3.4 - 8 μm and the long-wave spectrometer 8 - 15.4 μm. An optical schematic diagram of the spectrometer concept is shown in Figure 1. In addition to the IR spectrometers, the AIRS instrument contains six visible and near IR channels defined by bandpass filters. Every 2.667 seconds, AIRS will scan a ±49.5 degree swath across nadir in a direction perpendicular to the EOS satellite's ground track. The AIRS IFOV is 1.1 degree, providing a 13.5 km footprint at nadir from a 705 km orbital altitude. AIRS focal planes are comprised of linear arrays of mercury cadmium telluride (HgCdTe) detectors cooled to 60 K by a pair of split Sterling cycle coolers. The AIRS instrument will provide the capability to measure nominal scene radiances with a NEAT sensitivity of less than 0.2 K over most of the spectral band.
Simulated Wind Measurements With a Low Power/High PRF Space-Based Doppler Lidar
Authors: Emmitt G. D. , Wood S. A.
Published: February 2023

The concept of using a Doppler lidar to measure winds from space was first seriously posed by the Defense Meteorological Satellite Program Office (DMSP) of the USAF in the late 70's. NOAA, under contract to the USAF, conducted a feasibility study for a lidar system they called WINDSAT (Huffaker et al., 1980, 1984). Their conclusions were that given sufficient power (~ 10-20 J) winds could be measured throughout the troposphere and would provide global profiles of accuracy and density similar to those provided by the U.S. network of rawinsondes. The projected platform requirements and lidar development costs were significant and exceeded the existing resources available to the DMSP.
High Latitude Stratospheric Minor Gas Retrieval from Improved Limb Atmospheric Spectrometer (ILAS) Infrared Data
Authors: Yokota Tatsuya , Park Jae H. , Sasano Yasuhiro
Published: February 2023

The Improved Limb Atmospheric Spectrometer (ILAS)[1,2] is a grating spectrometer designed to measure vertical profiles of high latitude stratospheric constituents in a solar occultation mode (see Fig.1). ILAS will be installed on the Advanced Earth Observing Satellite (ADEOS), which is developed by National Space Development Agency of Japan (NASDA) and is scheduled to be launched in 1995. ADEOS has a sun-synchronous subrecurrent polar orbit at an altitude of 800 km with a 98.6 degree inclination. The equatorial crossing local time at descending node is currently planned to be in the period of 10:15 ~ 10:45 a.m. The recurrent period is 41 days and the design life time is 3 years. The latitude coverage of the ILAS occultation events for this particular orbit is shown in Fig. 2. The ILAS measurements are designed for the study of polar stratospheric chemistry.
Holographic Optical Elements as Conically Scanned Lidar Telescopes
Authors: Schwemmer Geary K. , Wilkerson Thomas D.
Published: February 2023

Recent developments in holographic optical elements (HOE) using volume phase holograms enables the development of a new class of light weight telescopes with specific advantages for lidar remote sensing instruments. One such device, a staring mode receiver has been fabricated for a laser range finder.1 In particular, a large aperture, narrow field of view telescope used in a conical scanning configuration can be constructed with a much smaller rotating mass compared to conventional designs which require a large flat scanning mirror or scanning the entire telescope assembly including the primary mirror, secondary, baffling, and the detector package or beam steering optics. Being a diffractive optic an HOE has spectral dispersion which can be utilized to advantage in a lidar system in which only one or more particular laser wavelengths are being observed. The spectral bandpass of the HOE can be made as narrow as 10 nm, replacing an optical filter in many applications. Other, unwanted wavelengths pass through the HOE undiffracted to be absorbed by a black backing. Thus, an HOE can be used to replace three separate components in a lidar telescope: the scanning mirror, the focusing mirror, and a narrowband interference filter. We also describe a method with which a multiplexed HOE can also be used simultaneously as a dichroic beamsplitter.
Estimates of Multiscattered Contributions to Lidar Returns Using Multi-Field-of-View Lidar Measurements
Authors: Hutt D.L. , Bissonnette L.R.
Published: February 2023

It is well known that backscatter lidar signals contain a multiscattered component. In many cases, especially when the optical depth along the lidar path is low, the magnitude of the multiscattered component is negligible. In some cases the multiscattered component may be significant, making the classical single scattering lidar equation inappropriate for interpretation of the lidar signal. In general, it is difficult to know whether or not multiscattered contributions are important without more information than is provided by a conventional single field-of-view (FOV) lidar.
Broadening of birefringent filter transmission bandwidth due to incident beam divergence
Authors: Notari Anthony , Lee H. Sang
Published: February 2023

Multistage birefringent filters have been employed for use as output frequency tuners in solid state and dye lasers. Our work with these devices has shown that the output pass band of the filter has a full width at half maximum (FWHM) on the order of 10Å, while theoretically one would expect it to be on the order of 1Å for a collimated beam. We have conducted a computer simulation study of the transmission characteristics of these filters and have found that a divergent beam will have a broader transmission curve than a nondivergent beam, and have determined the tolerance for divergence to produce an acceptably narrow pass band. We have found that a higher-order transverse mode pattern can produce a complicated transmission profile. We have also studied the effect of misalignment of individual stages in the filter to determine the tolerances in alignment of the stages. The temperature stability required to maintain the transmission peak wavelength of the filter within an allowable range has been obtained.
Remote Sensing Of Ozone Variability Using An Airborne Scanning Infrared Spectrometer
Authors: Carlson Grant S. , Jedlovec Gary J. , Suggs Ron J.
Published: February 2023

Interest in remote measurements of ozone has been fueled in recent years by growing concerns about the potential destruction of the earth's protective ozone layer. The discovery of the Antarctic "ozone hole" that stimulated so much scientific activity was based on satellite measurements made from polar orbit by the ultraviolet Total Ozone Mapping Spectrometer (TOMS). But the global maps and animated imagery from TOMS have also revealed that large values of total ozone are commonly observed near active mid-latitude weather systems (Chesters and Krueger, 1989). It would seem therefore that ozone imagery, if properly interpreted, might also provide valuable insight into the kinematic processes that occur in the upper tropospheric and lower stratospheric environments of rapidly developing frontal zone disturbances and jet streaks (Uccellini et al., 1985, Shapiro et al., 1982).
The NIES Ozone Lidar System for Observation of the Stratospheric Ozone
Authors: Nakane H. , Hayashida-Amano S. , Matsui I. , Sugimoto N. , Minato A. , Sasano Y.
Published: February 2023

Recent unpredicted ozone decrease in the polar and midlatitude regions shows importance of ground-based remole-sensing networks such as NDSC (Network for the Detection of Stratospheric Change). Though latitudinal networks are primarily important, the unexpected decrease of ozone in the northern midlatitude in winter and the inhomogeneity of the trends suggest the neccessily of complementary longitudinal networks. Japan could be one of the important locations from this point of view.
The Stratospheric Impact of the Eruption of Pinatubo
Authors: McCormick M. Patrick
Published: February 2023

The eruptions of the Philippine volcano Pinatubo (15.14°N, 120.35°W) in June 1991 caused the largest impact to stratospheric aerosols experienced probably in this century. Early estimates place the SO2 injected to altitudes of at least 30 km at 2 or more times that from the 1982 eruptions of El Chichon. El Chichon put about 6 megatonnes of SO2, or 12 megatonnes of sulfuric acid aerosol, into the lower-to-middle stratosphere making it the largest in the Northern Hemisphere for at least 50 years. An eruption of the magnitude of Pinatubo is important for studies of global change. In particular, its effects to cooling the Earth's surface and possibly masking greenhouse warming must be understood. The heterogeneous chemical effects of this new surface area and the potential for ozone reduction must also be studied. Other potential impacts include the possibility of increased cirrus cloud production and effects of this volcanic layer on producing artifacts in various ground-based and satellite-based remote sensor retrievals. Another effect clearly observed after El Chichon, was the serious crazing of acrylic windows on aircraft flying in polar regions and, therefore, at stratospheric altitudes where aircraft came into contact with the increased sulfuric acid aerosol produced by the El Chichon eruption.
Pinatubo in the Antarctic
Authors: Stefanutti L. , Del Guasta M. , Morandi M.
Published: February 2023

On July 20 and 21, 1991 over Dumont d'Urville a very strong lidar signal was detected over Dumont d'Urville in Antarctica at a height between 20 and 23 km. During a 6 hour measurement secondary layers appeared at lower heights, between 13 and 15 km. The scattering ratio was of the order of some hundreds. Such event could not be linked to Polar Stratospheric Clouds.
Airborne Infrared Observations of the Stratospheric Cloud From Mt. Pinatubo
Authors: Mankin William G. , Coffey M. T. , Goldman Aaron
Published: February 2023

Explosive volcanoes can inject large quantities of gases and particles into the stratosphere. These events can have important impacts on the atmosphere. Sulfur dioxide can be oxidized to produce sulfuric acid aerosols. The radiative effects of these particles can change the temperature of the stratosphere and hence the rates of the reactions that control ozone chemistry, as well as directly affecting climate. Volcanoes can also inject chlorine, in the form of HCl, directly into the stratosphere. Aerosol particles can serve as sites for heterogeneous chemical reactions releasing chlorine from temporary nonreactive reservoir species to free chlorine which can catalytically destroy ozone. Thus volcanic effects can have serious consequences for the ozone layer (Brasseur et al., 1991).
The Experimental Cloud Lidar Pilot Study (ECLIPS) Program
Authors: Martin C. , Platt R.
Published: February 2023

Although the general mean features of the global atmosphere can be simulated satisfactorily in models of the general circulation of the atmosphere (GCM's), it is not yet possible to simulate details of the global energy and water cycle to an acceptable accuracy. One of the main problems lies in modelling with sufficient accuracy the formation of clouds, their interactions with the radiation field, and the effects of precipitation.
Simplified Correction Techniques for Backscatter Errors in Differential Absorption Lidar Measurements of Ozone
Authors: Zhao Yanzeng
Published: February 2023

If the wavelength separation of the offline wavelength (λ1) and online wavelength (λ2) in an ozone differential absorption lidar (DIAL) system is large so that the backscattering coefficients, and the atmospheric extinction coefficients other than ozone, are significantly different, then corrections are needed to minimize the errors introduced by these differential coefficients. Browell et al1 proposed a Bernoulli solution for the mixing ratio at the offline wavelength to correct the backscatter error and made extensive analyses on the sensitivity of the backscatter correction to various parameters. Sasano2 proposed a more generalized technique to correct the backscatter error and obtain ozone concentration and aerosol backscatter profiles simultaneously by numerically integrating two equations. The present paper analyzes the mathematical expression for the backscatter error in a different way, and proposes simpler correction techniques accordingly.
Research on Stimulated Raman Scattering with Applications to Atmospheric Lidar
Authors: Chu Zhiping , Wilkerson Thomas D. , Singh Upendra
Published: February 2023

We describe research on stimulated Raman scattering (SRS) to extend conventional lasers into the near infrared where lidar systems can make important contributions to observations of the atmosphere(1)
Study On Stratospheric Trace Gas Measurement By 1.4 μm Laser Heterodyne Technique
Authors: Takeuchi Nobuo , Masusaki Hiroshi , Shang-Qian Wu
Published: February 2023

Trace gases are important in determining the dynamics, photochemistry, and radiation in the stratosphere. Water vapor1,2) is one of them. Its mixing ratio decreases with height up to the tropopause due to the saturation. The source of stratospheric water vapor is supposed mainly through the tropopause in the tropics region. The extraordinary dryness is a characteristic feature of the stratosphere. Its increase affects the global warming phenomena, and it also has a role as a source of stratospheric HOx radicals. In spite of importance, the behavior of water vapor is not sufficiently known. Global aspect will be clarified by UARS and EOS missions in addition to the currently operating SAGE sensor. Here we investigated the possibility of a compact, high sensitive laser heterodyne sensor (LHS) using a room-temperature operating laser diode (LD) in the near infrared (1.4 μm) region as the local oscillator. As well known, the diffraction limits the throughput of the available incident light power, which is unfavorable to shorter wavelength. However, the compactness and easy handling of a room-temperature operating LD prevails over the disadvantage, and may realize a compact low power-consumption balloon-borne/satellite-borne sensor.
High-Spectral-Resolution Rayleigh-Mie Lidar Measurement of Vertical Tropospheric Temperature and Aerosol Extinction Coefficient Profiles
Authors: She C. Y. , Alvarez R. J. , Caldwell L. M. , Krueger D. A.
Published: February 2023

Vertical profiles of aerosol and atmospheric properties are of considerable importance to atmospheric studies. Rayleigh-Mie scattering which contains the necessary information can be used to measure aerosol and atmospheric parameters if Rayleigh (molecular) and Mie (aerosol) scattering components can be effectively separated (She, 1990). In 1983, we suggested (Shimizu et al., 1983) that the use of a narrowband lidar system along with atomic resonance blocking filters has the sensitivity needed for a simultaneous measurement of backscatter ratio and atmospheric temperature. We have since developed a barium vapor filter with variable bandwidth and demonstrated the feasibility of the proposed scheme in a laboratory experiment with a single-frequency cw dye laser (Lehmann et al., 1986).
Atmospheric Water Vapor Column Determination: Comparisons Between Retrievals From Polar Orbiting Operational Satellites (NOAA and DMSP Series), Radiosondes and Analyses.
Authors: Husson N. , Scott N.A. , Chedin A. , Chaboureau J.P. , Claud C.
Published: February 2023

I. INTRODUCTION Accurate determination of the distribution of atmospheric water vapor is of major importance for improving our understanding of its role and variability in global meteorological and climatological processes as well as in space altimetry studies - e.g.TOPEX-POSEIDON programme -. An assessment of the accuracy of atmospheric water vapor retrieved from satellites, through comparisons with radiosonde measurements and ECMWF (European Center for Medium Range Weather Forecasts) analyses, has been performed. Two different types of satellite observations have been investigated : - observations from the TIROS-N Vertical Operational Sounder (TOVS) aboard the NOAA satellites; - observations from the SSM/I (Special Sensor Microwave/Imager) instrument aboard the DMSP satellites.
Spectral Calibration of the Improved Stratospheric and Mesospheric Sounder
Authors: Morris P. E. , Taylor F. W. , Ballard J.
Published: February 2023

The Improved Stratospheric and Mesospheric Sounder (ISAMS) is a limb-viewing infrared radiometer which measures thermal emission in 24 spectral bands, using both wideband (WB) and pressure modulator radiometer (PMR) techniques (Taylor, 1983). This enables the daily mapping over much of the Earth of temperature, the concentrations of 8 chemical species (water vapour, methane, ozone, nitric acid, nitrogen dioxide, nitric oxide, dinitrogen pentoxide, carbon monoxide) and aerosol opacity in the stratosphere and mesosphere. The instrument has eight separate focal planes, each consisting of a 4-element detector array, which are cooled by two mechanical coolers.
Correlation Spectrometer Observations of SO2, CO and OCS Emitted from Galeras Volcano, 9-10 January 1993
Authors: Charland A. , Morrow W. H. , Nicholls R. W. , Stix John
Published: February 2023

This paper describes remote sensing measurments of gasses emitted by Galeras volcano in the Colombian Andes prior to its eruption on 14 January 1993. In all, approximately eight hours of observations were made on 9-10 January in the UV and thermal IR. S02 was observed with a dispersive correlation spectrometer (Plumetracker) operating at 310 nm. OCS and CO were observed with a non-dispersive correlation spectrometer (GASCOFIL) operating at 4.8 microns. Preliminary analysis indicates SO2 levels of the order of 100 ppm-m just above the volcano, CO levels of 150 ppm-m and OCS of 6 ppm-m inside the inner cone of the volcano.
Characteristics of Clear-Sky Upper Tropospheric Water Vapor Content Determined from SAGE II Observations
Authors: Chiou Er-Woon , McCormick M.P. , Chu W.P.
Published: February 2023

Water vapor is one of the most important components of the atmosphere and is a key factor in shaping weather and climate. The demand for better water vapor measurements, especially in the upper troposphere, was pointed out by London (1957). With the increasing concern over the role of water vapor feedback in global warming, the need for a global water vapor data set with higher vertical resolution has become more acute (Arking, 1990).
Particle Size Characterization by means of Depolarization Measurements
Authors: Flesia C. , de Schoulepnikoff L.
Published: February 2023

Interest in the light scattering methods for the retrieval of the particle size distribution have grown in the last several years due to the unsatisfactory state of standard methods for the detection of small particles.
Monitor of Ejections of Industrial Pollutants in the Atmosphere Using A TV Camera
Authors: Banakh V.A. , Mironov V.L. , Morskii V.V. , Smalikho I.N. , Sutorikhin I.A.
Published: February 2023

One of the problems ecological monitoring of the atmosphere is operative diagnostics of ejection power of pollutants close to pollution sources, for example, plant chimneys /1/. At present, different methods of remote sensing of industrial pollutions have been developed, in particular, the methods based on the optical measurements. In this case, as is shown in /2/, the measurements of image brightness of smoke plumes with the use of a TV camera appear to be sufficiently informative.
SAGE II Measurements of Volcanic Aerosols
Authors: Veiga Robert E.
Published: February 2023

Volcanic injections of gaseous and crustal constituents directly into the stratosphere occur with low frequency. The mineralogical aerosols quickly settle out while the gases, primarily SO2, are converted into aerosols. Once in the stratosphere, the optical properties and the global dispersion of volcanic aerosols can be inferred using in situ particle samplers, photometers, lidars, and satellite instruments. Satellite remote sensing offers the opportunity to study atmospheric dynamics over the short term using the aerosols as a quasi-conserved tracer.
Summary of the Experimental Cloud Lidar Pilot Study ( ECLIPS ) at ISTS/York Lidar Observatory
Authors: Pal S. R. , Fong A. Y. , Carswell A. I.
Published: February 2023

Clouds play an important but complex role in modifying the solar radiative transfer in the atmosphere. To gain better insight into cloud physical and optical properties, which form the basis for cloud parameterization in general circulation models, the ECLIPS [1] was initiated in which about a dozen lidar groups have participated. The ECLIPS program has provided an opportunity to conduct lidar measurements of cloud systems simultaneously observed by a satellite (NOAA-10 or 11). A lidar measurement time series, typically of 3 hours encompasses a satellite overpass. Two ECLIPS phases (Sep-Nov 1989, Jun-Jul 1991) have provided consistent cloud lidar measurement time series on a variety of cloud formations. Our achievements in developing analytical methodologies to utilize large amounts of lidar data and to extract information on cloud physical and optical parameters are summarized in this paper. The behaviour of lidar derived cloud parameters in relation to important meteorological parameters will also be discussed.
Cloud Measurements with a Polarization Raman Elastic-Backscatter Lidar
Authors: Wandinger Ulla , Weitkamp Claus
Published: February 2023

The GKSS Raman elastic-backscatter lidar is part of the worldwide lidar network established for the ECLIPS (Experimental Cloud Lidar Pilot Study) project. A detailed review of the aims and philosophy of this international program is given in Ref. 1. During the first ECLIPS observational phase in autumn 1989 the GKSS lidar was also part of the ICE (International Cirrus Experiment) lidar network in the German Bight of the North Sea (Ref. 2). Measurements were taken on the island of Norderney (53.7° N, 7.2° E) between 18 September and 24 October 1989. In this campaign predominantly cirrus clouds were studied. The measurements of the second ECLIPS field phase were made at Geesthacht (53.5° N, 13.5° E) between 29 May and 27 June 1991. Each day two or three two-hour sessions centered around the overpass times of the satellites NOAA 10 and NOAA 11 were carried out.
Solar Blind Raman Scattering Measurements of Water Vapor Using a KrF Excimer Laser
Authors: Whiteman D. N. , Ferrare R. A. , Melfi S. H. , Evans K. D.
Published: February 2023

The use of Raman scattering for measurements of water vapor in the atmosphere during the night-time is well established1-4. Raman measurements of water vapor during the daytime are considerably more limited. The solar blind technique (SB) for making these measurements has received the most attention to date.
The Arecibo Observatory Daytime Lidar : Preliminary Results
Authors: Dighe Kalpak A. , Tepley Craig A. , Garcia Raul , Friedman Jonathan
Published: February 2023

The vertical propagation of atmospheric tides and acoustic gravity waves and their corresponding travelling ionospheric disturbances play a crucial role in the transportation and balance of momentum and energy in the earth's atmosphere. The unique availability of both radar and lidar instrumentation at Arecibo can provide simultaneous access to the neutral density, temperature and wind perturbations induced by such wave activity at mesospheric and stratospheric altitudes.
The Arecibo Observatory Lidar Upgrade: Possibilities for New Science.
Authors: Friedman Jonathan S. , Castleberg Paul A. , Dighe Kalpak A. , Tepley Craig A. , Kelley Michael C.
Published: February 2023

The Doppler-Rayleigh lidar at the Arecibo Observatory has been in operation since the spring of 1990. Since that time regular measurements have been conducted of the wind structure of the stratosphere and mesosphere above Puerto Rico. At the present time, the lidar is capable of measuring horizontal wind velocities in an altitude range from less than 10 km to nearly 60 km. The main purpose of the upgrade is to extend the upper limit of the Doppler-wind measurements to meet the lower limit of the incoherent scatter radar (ISR). This will be done by the completion of a large telescope and by adding resonance lidar capability. A benefit of the resonance scatter lidar, and one that is certainly not of secondary interest, is to study the density and dynamics of trace species near the mesopause.
Observation of Sea Fog Incursion with a Diode-Pumped YAG Portable Lidar
Authors: Takeuchi Nobuo , Okumura Hiroshi , Sugita Tadashi , Matsumoto Hironori , Kuwashima Shigesumi , Yamaguchi Satoshi
Published: February 2023

A portable lidar system has been strongly desired for the measurement of local area air pollution, boundary layer meteorology, plume dispersion and cloud physics. However, so far a compact and convenient lidar system has not been well developed. One of the authors constructed a pseudorandom code lidar (RM-CW lidar) system using a diode laser as a light source[1]. It has a limited performance due to the limited power. We proposed and presented a new system[2-3] based on a high repetitive operation, where we adopted a whole solid system using of a Q-switched diode-pumped YAG laser and an avalanche photodiode(APD). Here we report its application to a sea fog observation.
Observations of Winds of the Stratosphere and Mesosphere at Arecibo, Puerto Rico Using a Doppler Rayleigh Lidar
Authors: Tepley Craig A.
Published: February 2023

At the Arecibo Observatory we use a variety of radar and optical instruments to measure the properties of the Earth's atmosphere and ionosphere. With the incoherent scatter radar we are sensitive to the ionized portion of the upper atmosphere from about half an Earth radius (RE) down to nearly 60 km during daylight, and 100-150 km during the night when the molecular ionization of this lower part recombines. During both day and night, the winds and turbulent layer structures of the troposphere and stratosphere are accessible up to 25 km with the coherent scatter radar systems. We also use a variety of optical spectro-photometric instruments at Arecibo to study airglow emissions originating from various layers within the atmosphere. Because of the nature of the emitters and their corresponding chemistry, optical remote sensing more preferentially samples the condition of the neutral atmosphere. Thus, by combining simultaneous radar and optical techniques, we can investigate a variety of problems, such as the electrodynamics of the thermosphere, which require data on both the neutral and ionized atmosphere. Much of this instrumentation at Arecibo has been in operation and actively collecting data since the mid-1960s.
Doppler Lidar Observations of a Frontal Passage in the Vicinity of Steep Topography
Authors: Post Madison J. , Nieman Paul J. , Ralph F. Martin , Olivier Lisa D.
Published: February 2023

On September 25, 1992, we used NOAA's pulsed CO2 Doppler lidar (Post and Cupp, 1990) to observe the passage of a dry cold front across northeastern Colorado. This particular front was chosen because of 1) its dry nature, which minimized cloud cover and maximized the utility of the lidar, and 2) its intensity, exhibiting tropopause fold characteristics in the 12 h preceding the period of observations. Because of enhanced backscatter throughout the troposphere and lower stratosphere from the eruption of Mt. Pinatubo (in June, 1991), a much larger than normal volume of the atmosphere was observed.
Accuracy of Wet Troposphere Radio Path Delay Estimated from Infrared Emission
Authors: Parker J. W.
Published: February 2023

Several radio science applications require determination of the excess radio-propagation path delay caused by the earth's atmosphere. These include very long baseline interferometry, spacecraft tracking, and potentially detection of gravitational waves utilizing a link to a distant interplanetary spacecraft. At Ka band, the major source of variability of path delay is the fluctuations in the moisture content of the troposphere. The path-delay characterization requirements for a planned gravitational wave experiment are novel and challenging. The error contribution to the phase observations due to path delay variation must be reduced by nearly two orders of magnitude over that occurring naturally on time scales of 100 to 10,000 seconds. Current approaches relying on microwave water vapor radiometry with ancillary data can deliver one order of magnitude calibration of these fluctuations, and more advanced systems are under development within the 2001-2002 time frame of the Cassini mission to Saturn. The current work evaluates the potential for an alternative observational approach, using a ground-based Fourier transform spectrometer.
Multiple Element Mosaic Receiver for Optical Remote Sensing
Authors: Papen George C.
Published: February 2023

Compact lightweight optical receivers are desirable in many remote sensing applications. Here we report preliminary results of a novel reconfigurable multiple element mosaic receiver for incoherent light collection that is very efficient in terms of collection area per unit weight and per unit volume.
The NOAA 2 μm Coherent Doppler Lidar
Authors: Grund Christian J.
Published: February 2023

The NOAA Environmental Technology Laboratory has constructed a 200 Hz pulse repetition rate, 30 m range resolution, 2 μm wavelength Doppler lidar using coherent detection and a double-end CW-diode-pumped, injection-seeded, Q-switched Tm:LuYAG laser of our own design. Combined with a high speed scanner and advanced data system, the lidar design is optimized for the rapid measurement of boundary layer winds, turbulence fields, and structure. The system is housed in a standard seatainer to minimize overseas shipping costs. The seatainer is currently mounted on a semi-trailer to accommodate transport to domestic experiments. The lidar optics and control electronics have been assembled on a lightweight framework constructed for the NOAA P-3 aircraft to facilitate future airborne experiments.
The Water Vapor Continuum and its Role in Remote Sensing
Authors: Clough Shepard A.
Published: February 2023

The water vapor continuum plays an important role in atmospheric radiative transfer providing increased opacity between spectral lines over the full spectral region from the microwave to the visible. The continuum has a significant influence on atmospheric fluxes and cooling rates. Additionally the continuum is important to the physical solution of the inverse problem, the remote sensing of atmospheric state to retrieve temperature, water vapor, surface properties and other state parameters. There are two components to the continuum: the self-broadened continuum, dependent on the square of the partial pressure of water vapor, and the foreign-broadened continuum, dependent on the product of the water vapor partial pressure and the dry air pressure. As a consequence the self-broadened continuum tends to be more important in the lower atmosphere while the foreign-broadened continuum tends to be more important in the middle to upper troposphere. A comprehensive continuum model based on a single line shape for all transitions from the microwave to the visible has provided generally acceptable results (Clough et al., 1989 and Clough et al., 1980; hereafter CKD). The nadir and zenith spectral radiometric measurements with the University of Wisconsin HIS instrument have been particularly useful in establishing the general level of accuracy for the continuum. For most spectral regions the apparent error in the continuum is of the order of 10% or less. The term 'apparent' is used because it is difficult to unambiguously characterize the atmosphere, particularly with respect to aerosol loading and to sub-visual cloud effects. However, for special conditions of atmospheric state, measurements indicate that for specific and very limited spectral regions, errors in the CKD continuum may be significant. The modification for the current model has been developed in the context of two recent observation: (1) the measurement of the downwelling radiance at Kavieng, New Guinea by Westwater et al. (1994) which indicated that the self-broadened continuum gave rise to an 8K error in brightness temperature at 950 cm-1 for an atmosphere with ~6 precipitable cm of water vapor; and (2) a clear indication that the foreign continuum was in error in the wings of the 1600 cm-1 water vapor band as observed by Revercomb and colleagues at the U. of Wisconsin.
Radiative Transfer in Nonhomogeneous Cirrus Clouds: Application to Remote Sensing
Authors: Rao N.X. , Liou K.N.
Published: February 2023

From lidar measurements of cirrus clouds, it has been illustrated that the backscattering coefficients vary significantly in space as constructed from the time series of backscattering returns (Sassen 1990; Spinhirne and Hart 1990). A complete understanding of the radiative properties of cirrus clouds and their parameterizations would require specific investigation of the potential effects of cloud spatial inhomogeneity on the transfer of radiation. In this paper, we have developed a three-dimensional, nonhomogeneous radiative transfer model based on the successive orders of scattering approach coupled with discretization of the radiation field in spatial and angular coordinates. Using the retrieved optical depth from AVHRR high-resolution data (≈ 1×1 km2) (Ou et al. 1993; Rao et al. 1994) and the observed ice crystal size distribution information from balloon-borne replicators (Ou et al. 1994), we investigate the effect of spatial inhomogeneity on the reflected and transmitted solar radiances and fluxes for cirrus clouds.
Barium Ion Lidar: Analysis of a lidar system for measuring temperatures in the middle thermosphere (200-500 km)
Authors: Collins Richard L. , Stenbaek-Nielsen Hans
Published: February 2023

Resonance scattering techniques have enjoyed considerable successes in probing the upper atmosphere. Temperature lidars have used the hyperfine structure of the sodium resonance lines to measure temperatures at high resolution in the mesospheric sodium layer (80-100 km) [Fricke and von Zahn, 1989; Senft et al., 1994]. An iron lidar has been proposed to use the Maxwell-Boltzmann distribution of electronic states in two resonance lines to measure temperatures in the same altitude region [Gelbwachs, 1994], However, higher altitudes remain inaccessible due to the lack of a suitable naturally occurring resonance scattering target. In this paper we examine the hyperfine structure of the barium ion (Ball) and consider lidar probing of an artificial barium ion cloud as a method of measuring temperature in the middle thermosphere (200-500 km).
Estimation of Polar Stratospheric Cloud Infrared Extinction Climatology Using Visible Satellite Observations
Authors: Pitts Michael C. , Thomason Larry W.
Published: February 2023

Polar stratospheric clouds (PSCs) provide surfaces for heterogeneous processes which can dramatically alter the normal partitioning of odd nitrogen and chlorine families in the winter polar stratospheres (Solomon, 1990; Poole et al., 1992), setting up conditions for significant ozone depletion as manifested in the springtime Antarctic ozone hole. The spatial and temporal distribution of PSCs is important for parameterizing PSC occurrence in multidimensional photochemical models whose use is essential for fully understanding observed Antarctic ozone losses as well as for accessing the possibility of a similar phemonenon occurring in the future in the Arctic. The Stratospheric Aerosol Measurement (SAM) II sensor, a single-channel (1 µm) photometer launched into a Sun-synchronous orbit aboard the Nimbus 7 satellite in October 1978, provided a unique database to establish the climatology of PSCs. Poole and Pitts (1994) used the record of high-latitude aerosol extinction obtained by SAM II from 1979-1989 to establish the climatology of PSC occurrences in the Arctic and Antarctic. Unfortunately, little information about PSC composition or type was detectable from the single-wavelength SAM II data.
High Spectral Resolution Lidar Measurements of Extinction and Particle Size in Clouds
Authors: Eloranta E. W. , Piironen P.
Published: February 2023

The spectral width of light backscattered from molecules is increased due to Doppler shifts caused by the thermal motion of the molecules. The thermal motion of aerosol and cloud particles is much slower and the backscatter spectrum is nearly unchanged. The University of Wisconsin High Spectral Resolution Lidar (HSRL) measures optical properties of the atmosphere by separating the Doppler-broadened molecular backscatter return from the unbroadened aerosol return1. The molecular backscatter cross section can be calculated from the molecular density profile. Thus, observing the magnitude of the measured molecular signal relative to the computed profile allows unambiguous measurement of the atmospheric extinction profile. The ratio of the aerosol return to the molecular return along with the computed molecular cross section provides direct measurement of the aerosol backscatter cross section.