Many astrophysical applications require precise wavelength calibration of high resolution spectra. Calibration sources for this purpose at near-infrared wavelengths are sparse. We present an experimental setup for an electrodeless microwave discharge lamp that produces molecular band emission spectra. The discharge is sustained inside a glass cell filled with a combination of different gases producing CN molecules with many spectral lines in the wavelength range between 1 μm and 2.5 μm. We investigate this lamp in terms of its usability for wavelength calibration in high resolution spectroscopy. In this conference contribution, we present the experimental setup and the characterization of the calibration source in terms of line identification, line intensities, and line density. We find approximately 20,000 lines in the spectral region of 1 - 2 μm with relative peak intensities in a range of two orders of magnitude. The results from a first endurance test show that the durability of the spectrum requires careful attention in the course of further development.
SciSat-1, otherwise known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth orbit (altitude 650 km, inclination 74 degrees) in August 2003. The primary instrument onboard ACE is a high resolution (maximum path difference ± 25 cm) Fourier Transform Spectrometer (FTS) operating from 2.4 to 13.3 microns (750-4100 cm-1). The satellite also features a dual spectrograph known as MAESTRO with wavelength coverage 280-1000 nm and resolution 1-2 nm. A pair of filtered CMOS detector arrays takes images of the sun at 0.525 and 1.02 nm. Working primarily in solar occultation, the satellite provides altitude profile information for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest. Scientific goals for ACE include: (1) understanding the chemical and dynamical processes that control the distribution of ozone in the stratosphere and upper troposphere; (2) exploring the relationship between atmospheric chemistry and climate change; (3) studying the effects of biomass burning in the free troposphere; and (4) measuring aerosols to reduce the uncertainties in their effects on the global energy balance.
SciSat-1, otherwise known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth orbit (altitude 650 km, inclination 74 degrees) in August 2003. The primary instrument onboard ACE is a high resolution (maximum path difference ± 25 cm) Fourier Transform Spectrometer (FTS) operating from 2.4 to 13.3 microns (750-4100 cm-1). The satellite also features a dual spectrograph known as MAESTRO with wavelength coverage 280-1000 nm and resolution 1-2 nm. A pair of filtered CMOS detector arrays takes images of the sun at 0.525 and 1.02 nm. Working primarily in solar occultation, the satellite provides altitude profile information for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest. Scientific goals for ACE include: (1) understanding the chemical and dynamical processes that control the distribution of ozone in the stratosphere and upper troposphere; (2) exploring the relationship between atmospheric chemistry and climate change; (3) studying the effects of biomass burning in the free troposphere; and (4) measuring aerosols to reduce the uncertainties in their effects on the global energy balance.
ACE is a Canadian satellite mission that will provide measurements leading to an improved understanding of the chemical and dynamical processes that control the distribution of ozone in the stratosphere. The ACE instruments are a Fourier transform infrared spectrometer, a UV/visible/near IR spectrograph and a two-channel solar imager, all working in solar occultation mode. ACE was successfully launched on August 12, 2003.
The Atmospheric Chemistry Experiment (ACE) was launched in August 2003 on board the Canadian scientific satellite SciSat-1. The ACE payload consists of two instruments: ACE-FTS, a high resolution (0.02 cm-1) Fourier transform infrared spectrometer and MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation), a dual UV-visible-NIR spectrograph. Primarily, the two instruments use a solar occultation technique to make measurements of trace gases, temperature, pressure and atmospheric extinction. It will also be possible to make near-nadir observations with the ACE instruments.
The on-orbit commissioning of the instruments and spacecraft were undertaken in the months following launch. At the end of this period, a series of science-oriented commissioning activities were undertaken. These activities had two aims: the first was to verify and extend the measurement results obtained during the pre-launch Science Calibration Test campaign and the second was to confirm appropriate parameters and establish procedures for operational measurements (occultation and near-nadir observations and exo-atmospheric calibration measurements). One of the most important activities was to determine the relative location of each instrument field of view and optimize the pointing of the sun-tracker to provide the best viewing for both instruments.
KEYWORDS: Fourier transforms, Sensors, Databases, Signal to noise ratio, Atmospheric modeling, Data modeling, Imaging systems, Molecules, Satellites, Temperature metrology
The SCISAT-1 mission, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission to investigate the chemical and dynamical processes that control the distribution of ozone in the stratosphere and upper troposphere. The satellite is scheduled to launch in August 2003, carrying two main instruments: a high-resolution infrared Fourier transform spectrometer (ACE-FTS) and a dual grating UV-Vis-NIR spectrometer known as MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) both operating primarily in solar occultation mode. Aspects of the mission pertaining to work done by ACE science team members from the University of Waterloo will be described, such as: the ACE-FTS forward model for retrieval of temperature, pressure and VMR profiles; ACE-FTS instrument testing and results; and the ACE Database along with data storage and processing hardware.
SciSat-1, otherwise known as the Atmospheric Chemistry Experiment (ACE), is a satellite mission designed for remote sensing of the Earth’s atmosphere using occultation spectroscopy. It has been developed under the auspices of the Canadian Space Agency and is scheduled for launch in August 2003. The suite of instruments on the satellite consists of a high-resolution (25 cm maximum path difference) Fourier Transform Spectrometer (FTS) operating in the infrared (2.4 to 13.3 microns), a UV/Visible Spectrometer operating between 0.285 and 1.03 microns with a resolution of 1 to 2 nm, and a pair of filtered imagers operating at 1.02 and 0.525 microns. The primary science goal of the ACE mission is to investigate the chemical and dynamical processes that govern ozone distribution in the stratosphere and upper troposphere. To this end, vertical profiles for trace gases, aerosols, temperature and pressure will be deduced from analysis of the solar occultation spectra. In particular, the role of heterogeneous reactions on ozone loss will be investigated, with a focus on the Arctic winter stratosphere.
SCISAT-1, the Atmospheric Chemistry Experiment, will use the solar occultation technique to make measurements of trace gases, atmospheric extinction, temperature, and pressure in the stratosphere and upper troposphere. The accuracy and reliability of the ACE results will be demonstrated through a validation program including ground-, balloon-, and satellite-based observations. This program will be ongoing throughout the lifetime of the mission. To provide sufficient global coverage, a worldwide group of participants will be collaborating with the ACE Validation team. Descriptions and locations of the validation experiments are given.
ACE is a Canadian satellite mission that will measure and help to understand the chemical and dynamical processes that control the distribution of ozone in the stratosphere. The ACE instruments are a Fourier transform infrared spectrometer, a UV/visible/near IR spectrograph and a two channel solar imager, all working in solar occultation mode.
Scisat-1, otherwise known as the Atmospheric Chemistry Experiment, is a satellite mission designed for remote sensing of the Earth's atmosphere using occultation spectroscopy. The primary goal of the mission is to investigate the chemical and dynamical processes that govern ozone distribution in the stratosphere and upper troposphere. It has been developed under the auspices of the Canadian Space Agency and is scheduled for launch in December of 2002. The primary instrument on board Scisat-1 is a high resolution Fourier transform spectrometer (FTS) operating in the infrared. Pressure and temperature as a function of altitude will be determined from the FTS measurements through analysis of carbon dioxide absorption. Volume mixing ratio (vmr) profiles will be retrieved for more than thirty molecules of atmospheric interest. Both the pressure/temperature and vmr retrievals use non-linear least squares Global Fit type approaches. For the pressure/temperature analysis, several variations are being developed; the choice of which version to implement depends on the quality of the pointing information obtained from the satellite. In the case of poor pointing knowledge, tangent height separations between measurements will be determined directly from the FTS data (simultaneously with the pressure and temperature determination) through the imposition of hydrostatic equilibrium.
Fourier transform vibration-rotation emission spectra of various molecules including AlH, AlD, GaH, GaD, InH and InD were measured with the Bruker IFS 120 HR spectrometer at Waterloo. These molecules were made by the reaction of hot metal vapors with hydrogen and deuterium at 1400 degree(s)C - 1500 degree(s)C. In the GaD spectrum, the SiO impurity was noted. In addition to the usual spectroscopic constants, potential energy curves were generated from fitting the line positions by direct numerical solution of the Schrodinger equation using a parameterized potential energy curve.
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