A5073434758- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Atmospheric aerosols and clouds
- Calibration and Measurement Techniques
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Air Quality Monitoring and Forecasting
- Astro and Planetary Science
- Planetary Science and Exploration
- Water Quality Monitoring and Analysis
- Infrared Target Detection Methodologies
- Laser-induced spectroscopy and plasma
- Engineering Applied Research
- Impact of Light on Environment and Health
- Urban Heat Island Mitigation
- Optical Polarization and Ellipsometry
- Advanced Chemical Sensor Technologies
- Icing and De-icing Technologies
- Climate variability and models
- Spectroscopy and Laser Applications
- Remote Sensing and Land Use
- Marine and coastal ecosystems
- Data Quality and Management
Jet Propulsion Laboratory
2013-2025
California Institute of Technology
2012-2021
Colorado State University
2014-2015
Space Research Organisation Netherlands
2008-2010
Heidelberg University
2004-2008
Max Planck Institute for Chemistry
2008
Multi AXis Differential Optical Absorption Spectroscopy (MAX‐DOAS) observations of the oxygen dimer O 4 which can serve as a new method for determination atmospheric aerosol properties are presented. Like established methods, e.g., Sun radiometer and LIDAR measurements, MAX‐DOAS determine optical under conditions (not dried). However, novel technique has two major advantages: It utilizes differential absorption structures thus does not require absolute radiometric calibration. In addition,...
Abstract. The results of a comparison exercise radiative transfer models (RTM) various international research groups for Multiple AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) viewing geometry are presented. Besides the assessment agreement between different models, second focus was systematic investigation sensitivity MAX-DOAS technique under geometries and aerosol conditions. In contrast to previous exercises, box-air-mass-factors (box-AMFs) atmospheric height layers were...
Abstract. An intercomparison of different radiometric techniques measuring atmospheric photolysis frequencies j(NO2), j(HCHO) and j(O1D) was carried out in a two-week field campaign June 2005 at Jülich, Germany. Three double-monochromator based spectroradiometers (DM-SR), three single-monochromator with diode-array detectors (SM-SR) seventeen filter radiometers (FR) (ten j(NO2)-FR, seven j(O1D)-FR) took part this comparison. For all spectroradiometer results agreed within ±3%. j(HCHO),...
Abstract. New generations of space-borne spectrometers for the retrieval atmospheric abundances greenhouse gases require unprecedented accuracies as variability long-lived is very low. These instruments, such GOSAT and OCO-2, typically use a high spectral resolution oxygen channel (O2 A-band) in addition to CO2 CH4 channels discriminate changes photon path-length distribution from actual trace gas amount changes. Inaccurate knowledge distribution, determined by scatterers atmosphere, prime...
Abstract. We present the results of an intercomparison exercise between six different radiative transfer (RT) models carried out in framework QUILT, EU funded project based on exploitation Network for Detection Stratospheric Change (NDSC). RT modelling is important step interpretation Differential Optical Absorption Spectroscopy (DOAS) observations. It allows conversion slant column densities (SCDs) into vertical (VCDs) using calculated air mass factors (AMFs). The originality our study...
Abstract. Due to the well-defined vertical profile of O2 in atmosphere, strong A-band (757–774 nm) has long been used estimate distributions aerosol/cloud from space. We extend this approach include part B-band (684–688 as well. SCIAMACHY onboard ENVISAT is first instrument provide spectral data at moderate resolution (0.2–1.5 UV/VIS/NIR including both A- and B-bands. Using specifications, we make combined use these bands an optimal estimation algorithm. Theoretical studies show that our...
Global data sets of total column precipitable water and cloud cover derived from the Ozone Monitoring Experiment (GOME) are analyzed with respect to anomalies induced by strong El Niño 1997/1998. In contrast other satellite observations vapor, GOME nadir in visible spectral range similar sensitivity over both land ocean. addition, they sensitive particular vapor concentration close surface where a major fraction is present. Information on atmospheric was observed broadband intensity as well...
The past two decades have seen tremendous improvements in greenhouse gas (GHG) remote sensing from space, including global area flux mappers like SCIAMACHY, GOSAT, OCO-2, GOSAT-2, TROPOMI and OCO-3 among others, with more missions planned, such as CO2M. In the decade there has also been an increase GHG point source imagers, a field that grown rapidly after initial successes using AVIRIS-NG subsequent VSWIR spectrometers (coarser spectral resolution over broader range). While mapper effective...
The Markov chain formalism for polarized radiative transfer through a vertically inhomogeneous atmosphere is linearized comprehensively with respect to the aerosol and polarizing surface properties. For verification, numerical results are compared those obtained by finite difference method. We demonstrate use of code as part retrieval properties an overlying black Fresnel-reflecting ocean surface.
Abstract. Clouds play a crucial role in Earth's radiative budget, yet their climate feedbacks are poorly understood. The advent of space-borne high resolution spectrometers probing the O2 A band, like GOSAT and OCO-2, could make it possible to simultaneously retrieve vertically resolved cloud parameters that vital thereby allowing reduction corresponding uncertainty due clouds. Such retrievals would also facilitate air mass bias measurements CO2 columns. In this work, hyperspectral,...
This work is a theoretical exploration facilitating the interpretation of polarimetric observations in terms cloudiness, rotational velocities, and effective temperatures brown dwarfs (BDs). An envelope scatterers like free electrons, atoms/molecules, or haze/clouds affects Stokes vector radiation emitted by oblate bodies. Due to high rotation rates, BDs can be considerably oblate. We present conics-based radiative transfer scheme for computing disk-resolved disk-integrated polarized...
Scattering processes in the atmosphere of a fast-rotating brown dwarf (BD) or self-luminous extrasolar giant planet (EGP) produce distinct polarimetric, addition to spectrometric, signatures. An ability unambiguously interpret these signals would improve our understanding their atmospheric evolution, structure, and dynamics. To this end, we have incorporated molecular opacities define wavelength-dependent vertical structure as function internal energy, surface gravity, metallicity BD. This...
We propose a method for identifying clear-sky scenarios from measurement time series over satellite-observed ground pixels of unknown surface albedo and aerosol type. The lack general monotonic relationship between loading observed reflectance encumbers the ordering observation according to loading. This problem is ameliorated by using two wavelengths at which albedos are known differ. Treating an as being cloud/aerosol free allows determination corresponding Lambertian equivalent albedo,...
Abstract. New generations of space-borne spectrometers for the retrieval atmospheric abundances greenhouse gases require unprecedented accuracies as variability long-lived is very low. These instruments, such GOSAT and OCO-2, typically use a high spectral resolution oxygen channel (O2 A-band) in addition to CO2 CH4 channels discriminate changes photon path-length distribution from actual trace gas amount changes. Inaccurate knowledge distribution, determined by scatterers atmosphere, prime...
Missions like the upcoming Roman Space Telescope and its follow-on missions, Habitable Exoplanet Observatory (HabEx) Large UV/Optical/IR Surveyor (LUVOIR), will provide direct imaging observations of stellar light reflected by exoplanets with successively closer orbits. The synergistic use ground-based polarimeters Gemini Planet Imager Very Telescope/Spectro-Polarimetric High-contrast Research instrument (SPHERE) would allow us to characterize cloudy exoplanet atmospheres using...