A5049587549- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Calibration and Measurement Techniques
- COVID-19 impact on air quality
- Spectroscopy and Laser Applications
- Marine and coastal ecosystems
- Vehicle emissions and performance
- Water Quality Monitoring and Analysis
- Infrared Target Detection Methodologies
- Satellite Image Processing and Photogrammetry
- Gas Sensing Nanomaterials and Sensors
- Climate Change and Health Impacts
- Adaptive optics and wavefront sensing
- Advanced Chemical Sensor Technologies
- CCD and CMOS Imaging Sensors
- GNSS positioning and interference
- Spacecraft Design and Technology
- Inertial Sensor and Navigation
- Satellite Communication Systems
- Impact of Light on Environment and Health
- Image and Video Quality Assessment
Goddard Space Flight Center
2015-2024
University of Maryland, Baltimore County
2015-2024
SciGlob (United States)
2023-2024
University of Maryland, Baltimore
2009-2023
Systems Technology (United States)
2020-2022
Earth System Science Interdisciplinary Center
2014-2020
University of Maryland, College Park
2010-2020
Waldrappteam
2018
Morgan State University
2012
Science Systems and Applications (United States)
2002-2004
Long‐term measurements by the AERONET program of spectral aerosol optical depth, precipitable water, and derived Angstrom exponent were analyzed compiled into an properties climatology. Quality assured monthly means are presented described for 9 primary sites 21 additional multiyear with distinct regimes representing tropical biomass burning, boreal forests, midlatitude humid climates, dry oceanic sites, desert background sites. Seasonal trends each these nine discussed climatic averages presented.
Vertical column amounts of nitrogen dioxide, C(NO 2 ), are derived from ground‐based direct solar irradiance measurements using two new and independently developed spectrometer systems, Pandora (Goddard Space Flight Center) MFDOAS (Washington State University). We discuss the advantages ) retrievals based on Direct Sun ‐ Differential Optical Absorption Spectroscopy (DS‐DOAS). The data presented field campaigns at Aristotle University (AUTH), Thessaloniki, Greece; a second campaign involving...
Significance Recent work in Los Angeles has shown that urban volatile organic compound (VOC) emissions from consumer and industrial products—termed chemical products (VCPs)—are now an important source of ozone precursors. Using advancements VOC instrumentation, we show VCP are ubiquitous regions can be identified via unique fingerprints. Through detailed modeling, VCPs as to production fossil fuel VOCs the chemistry have significant impacts on model simulations key atmospheric processes....
Five Microtops II Sun photometers were studied in detail at the NASA Goddard Space Flight Center (GSFC) to determine their performance measuring aerosol optical thickness (AOT or τ a λ ) and precipitable column water vapor ( W ). Each derives from measured signals four wavelengths (340, 440, 675, 870 nm), 936 nm signal measurements. Accuracy of determination depends on reliability relevant channel calibration coefficient V 0 Relative by transfer parameters more accurate photometer (such as...
Abstract. In June 2009, 22 spectrometers from 14 institutes measured tropospheric and stratospheric NO2 the ground for more than 11 days during Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI), at Cabauw, NL (51.97° N, 4.93° E). All visible instruments used a common wavelength range set cross sections spectral analysis. Most were multi-axis design with analysis by differential spectroscopy software (MAX-DOAS), whose non-zenith slant columns compared examining...
Abstract. In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants for period 17 d during the Second Cabauw Intercomparison campaign Nitrogen Dioxide measuring Instruments (CINDI-2) that took place at Cabauw, Netherlands (51.97∘ N, 4.93∘ E). We report on outcome formal semi-blind intercomparison exercise, which was held under umbrella Network Detection Atmospheric Composition Change (NDACC) and European Space Agency (ESA). The three major goals...
Abstract. We present intercomparison results for formaldehyde (HCHO) slant column measurements performed during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI) that took place in Cabauw, Netherlands, summer 2009. During two months, nine atmospheric research groups simultaneously operated MAX-DOAS (MultiAXis Differential Optical Absorption Spectroscopy) instruments various designs to record UV-visible spectra scattered sunlight at different elevation...
Abstract. From June to July 2009 more than thirty different in-situ and remote sensing instruments from all over the world participated in Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI). The took place at KNMI's Experimental Site Atmospheric Research (CESAR) Netherlands. Its main objectives were determine accuracy of state-of-the-art ground-based measurement techniques detection atmospheric nitrogen dioxide (both sensing), investigate their usability...
Abstract. NASA deployed the GeoTASO airborne UV–visible spectrometer in May–June 2017 to produce high-resolution (approximately 250 m×250 m) gapless NO2 datasets over western shore of Lake Michigan and Los Angeles Basin. The results collected show that tropospheric vertical column retrievals compare well with ground-based Pandora observations (r2=0.91 slope 1.03). Apparent disagreements between two measurements can be sensitive coincidence criteria are often associated large local...
Abstract. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) and direct sun NO2 vertical column network data are used to investigate the accuracy of tropospheric measurements GOME-2 instrument on MetOp-A satellite platform OMI Aura. The study is based 23 MAX-DOAS 16 instruments at stations distributed worldwide. A method quantify correct for horizontal dilution effects in heterogeneous field conditions proposed. After systematic application this correction urban sites, found...
Abstract. Airborne imaging differential optical absorption spectroscopy (DOAS), ground-based stationary DOAS, and car DOAS measurements were conducted during the S5P-VAL-DE-Ruhr campaign in September 2020. The area is located Rhine-Ruhr region of North Rhine-Westphalia, western Germany, which a pollution hotspot Europe comprising urban large industrial sources. are used to validate spaceborne NO2 tropospheric vertical column density (VCD) data products from Sentinel-5 Precursor (S5P)...
We present new, high precision, temporal resolution measurements of total column ozone (TCO) amounts derived from ground‐based direct‐sun irradiance using our recently deployed Pandora single‐grating spectrometers. Pandora's small size and portability allow deployment at multiple sites within an urban air‐shed development a monitoring network for studying small‐scale atmospheric dynamics, spatial heterogeneities in trace gas distribution, local pollution conditions, photochemical processes...
Abstract. Retrievals of total column NO2 (TCNO2) are compared for 14 sites from the Ozone Measuring Instrument (OMI using OMNO2-NASA v3.1) on AURA satellite and multiple ground-based PANDORA spectrometer instruments making direct-sun measurements. While OMI accurately provides daily global distribution retrieved TCNO2, almost always underestimates local amount TCNO2 by 50 % to 100 in polluted areas, while occasionally value exceeds that measured at very clean sites. Compared or aircraft...
Abstract. Nine Pandora spectrometer instruments (PSI) were installed at eight sites in South Korea as part of the KORUS-AQ (Korea U.S.-Air Quality) field study integrating information from ground, aircraft, and satellite measurements for validation remote sensing air-quality studies. The PSI made direct-sun total vertical column NO2, C(NO2), with high precision (0.05 DU, where 1 DU =2.69×1016 molecules cm−2) accuracy (0.1 DU) that retrieved using spectral fitting techniques. Retrieval...
Abstract. Nitrogen oxides (NOx≡NO+NO2) in the NOx-limited upper troposphere (UT) are long-lived and so have a large influence on oxidizing capacity of formation greenhouse gas ozone. Models misrepresent NOx UT, observations to address deficiencies models sparse. Here we obtain year near-global seasonal mean mixing ratios NO2 UT (450–180 hPa) at 1∘×1∘ by applying cloud-slicing partial columns from TROPOMI. This follows refinement algorithm with synthetic GEOS-Chem chemical transport model....
Abstract. The Korea–United States Air Quality Study (KORUS-AQ) conducted during May–June 2016 offered the first opportunity to evaluate direct-sun observations of formaldehyde (HCHO) total column densities with improved Pandora spectrometer instruments. measurements highlighted in this work were both Seoul megacity area at Olympic Park site (37.5232∘ N, 27.1260∘ E; 26 m a.s.l.) and a nearby rural downwind city Mount Taehwa research forest (37.3123∘ 127.3106∘ 160 a.s.l.). Evaluation these was...
Abstract. A comparison of retrieved total column ozone (TCO) amounts between the Pandora #34 spectrometer system and Dobson #061 spectrophotometer from direct-sun observations was performed on roof Boulder, Colorado, NOAA building. This paper, part an ongoing study, covers a 1-year period starting 17 December 2013. Both standard TCO retrievals required correction, TCOcorr = (1 + C(T)), using monthly varying effective temperature, TE, derived temperature profile climatology. The correction is...
The COVID-19 pandemic created an extreme natural experiment in which sudden changes human behavior and economic activity resulted significant declines nitrogen oxide (NO x ) emissions, immediately after strict lockdowns were imposed. Here we examined the impact of multiple waves response phases on dioxide (NO2) dynamics role meteorology shaping relative contributions from different emission sectors to NO2 pollution post-pandemic New York City. Long term (> 3.5 years), high frequency...
Total-column nitrogen dioxide (NO2) data collected by a ground-based sun-tracking spectrometer system (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA's Langley Research Center in Hampton, Virginia were analyzed to study the relationship between total-column surface NO2 measurements. The measurements span more than year cover all seasons. Surface mixing ratios are estimated via application of planetary boundary-layer (PBL) height correction factor. This PBL...
An analysis is presented for both ground- and satellite-based retrievals of total column ozone nitrogen dioxide levels from the Washington, D.C., Baltimore, Maryland, metropolitan area during NASA-sponsored July 2011 campaign Deriving Information on Surface COnditions Column VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ). Satellite Ozone Monitoring Instrument (OMI) Aura satellite are used, while Pandora spectrometers provide amounts ground. We found that OMI agree...
Coastal environments are highly dynamic, and characterized by short-term, local-scale variability in atmospheric oceanic processes. Yet, high-frequency measurements of composition, particularly nitrogen dioxide (NO2) ozone (O3) dynamics, scarce over the ocean, introducing uncertainties satellite retrievals coastal ocean biogeochemistry ecology. Combining from different platforms, Korea-US Ocean Color Air Quality field campaign provided a unique opportunity to capture, for first time, strong...
Abstract Total columnar water vapor (CWV), nitrogen dioxide (NO 2 ), and ozone (O 3 ) are derived from a newly developed, hyperspectral airborne Sun‐sky spectrometer (4STAR) for the first time during two intensive phases of Two‐Column Aerosol Project (TCAP) in summer 2012 winter 2013 aboard DOE G‐1 aircraft. We compare results with coincident measurements. find 0.045 g/cm (4.2%) negative bias 0.28 (26.3%) root‐mean‐square difference (RMSD) layer comparison an situ hygrometer overall RMSD...
Abstract Near‐surface air quality (AQ) observations over coastal waters are scarce, a situation that limits our capacity to monitor pollution events at land‐water interfaces. Satellite measurements of total column (TC) nitrogen dioxide (NO 2 ) useful proxy for combustion sources, but the once daily snapshots available from most sensors insufficient tracking diurnal evolution and transport pollution. Ground‐based remote like Pandora Spectrometer Instrument (PSI) have been developed verify...
The new infrared radiometer (conveyable low-noise for measurements of atmosphere and ground surface targets, or CLIMAT) is a highly sensitive field instrument designed to measure brightness temperatures radiances in the infrared, from level, an aircraft. It can be equipped with up six channels 8–14-μm range. This characterized by its portability (total mass less than 5 kg), self-sufficiency, automated operation. operated either manually automatically. optical head contains objective lens...