A5083375903- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Calibration and Measurement Techniques
- Aeolian processes and effects
- Air Quality and Health Impacts
- Climate variability and models
- Fire effects on ecosystems
- Marine and coastal ecosystems
- Cryospheric studies and observations
- Oceanographic and Atmospheric Processes
- Meteorological Phenomena and Simulations
- Remote Sensing and Land Use
- Solar Radiation and Photovoltaics
- Geochemistry and Geologic Mapping
- Remote Sensing in Agriculture
- Urban Heat Island Mitigation
- Oil, Gas, and Environmental Issues
- Space exploration and regulation
- Polar Research and Ecology
- Vehicle emissions and performance
- Water Quality Monitoring and Analysis
- Astro and Planetary Science
Goddard Space Flight Center
2015-2024
National Aeronautics and Space Administration
2011
University of Maryland, Baltimore County
1999-2004
General Electric (Norway)
2001
RTX (United States)
1999
Laboratoire d'Optique Atmosphérique
1999
Science Systems and Applications (United States)
1999
Centre d'Études Spatiales de la Biosphère
1999
Systems Technology (United States)
1999
Université Paris Cité
1999
Abstract. The twin Moderate resolution Imaging Spectroradiometer (MODIS) sensors have been flying on Terra since 2000 and Aqua 2002, creating an extensive data set of global Earth observations. Here, we introduce the Collection 6 (C6) algorithm to retrieve aerosol optical depth (AOD) size parameters from MODIS-observed spectral reflectance. While not a major overhaul previous 5 (C5) version, there are enough changes that significant impacts products their interpretation. C6 will be created...
[1] Our understanding of the global dust cycle is limited by a dearth information about sources, especially small-scale features which could account for large fraction emissions. Here we present global-scale high-resolution (0.1°) mapping sources based on Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue estimates optical depth in conjunction with other data sets including land use. We ascribe to natural and anthropogenic (primarily agricultural) origins, calculate their...
We estimated global fine particulate matter (PM2.5) concentrations using information from satellite-, simulation- and monitor-based sources by applying a Geographically Weighted Regression (GWR) to geophysically based satellite-derived PM2.5 estimates. Aerosol optical depth multiple satellite products (MISR, MODIS Dark Target, SeaWiFS Deep Blue, MAIAC) was combined with simulation (GEOS-Chem) upon their relative uncertainties as determined ground-based sun photometer (AERONET) observations...
The aerosol products retrieved using the Moderate Resolution Imaging Spectroradiometer (MODIS) collection 5.1 Deep Blue algorithm have provided useful information about properties over bright‐reflecting land surfaces, such as desert, semiarid, and urban regions. However, many components of C5.1 retrieval needed to be improved; for example, use a static surface database estimate reflectances. This is particularly important regions mixed vegetated nonvegetated which may undergo strong seasonal...
Abstract The Moderate Resolution Imaging Spectroradiometer (MODIS) Atmospheres data product suite includes three algorithms applied to retrieve midvisible aerosol optical depth (AOD): the Enhanced Deep Blue (DB) and Dark Target (DT) over land, a DT over‐water algorithm. All have been refined in recent “Collection 6” (C6) MODIS reprocessing. In particular, DB has expanded cover vegetated land surfaces as well brighter desert/urban areas. Additionally, new “merged” set which draws from all is...
Exposure to outdoor fine particulate matter (PM2.5) is a leading risk factor for mortality. We develop global estimates of annual PM2.5 concentrations and trends 1998-2018 using advances in satellite observations, chemical transport modeling, ground-based monitoring. Aerosol optical depths (AODs) from advanced products including finer resolution, increased coverage, improved long-term stability are combined related surface geophysical relationships between AOD simulated by the GEOS-Chem...
The “Deep Blue” aerosol optical depth (AOD) retrieval algorithm was introduced in Collection 5 of the Moderate Resolution Imaging Spectroradiometer (MODIS) product suite, and complemented existing “Dark Target” land ocean algorithms by retrieving AOD over bright arid surfaces, such as deserts. forthcoming 6 MODIS products will include a “second generation” Deep Blue algorithm, expanding coverage to all cloud‐free snow‐free surfaces. dataset also provide an estimate absolute uncertainty on at...
Annual global satellite-based estimates of fine particulate matter (PM2.5) are widely relied upon for air-quality assessment. Here, we develop and apply a methodology monthly uncertainties during the period 1998–2019, which combines satellite retrievals aerosol optical depth, chemical transport modeling, ground-based measurements to allow characterization seasonal episodic exposure, as well aid management. Many densely populated regions have their highest PM2.5 concentrations in winter,...
Abstract. Both sensor calibration and satellite retrieval algorithm play an important role in the ability to determine accurately long-term trends from data. Owing unprecedented accuracy stability of its radiometric calibration, SeaWiFS measurements exhibit minimal uncertainty with respect calibration. In this study, we take advantage well-calibrated set by applying a newly-developed aerosol optical depth (AOD) over land ocean investigate distribution AOD, identify emerging patterns global...
Abstract. Aerosol variations and trends over different land ocean regions from 1980 to 2009 are analyzed with the Goddard Chemistry Radiation Transport (GOCART) model observations multiple satellite sensors available ground-based networks. Excluding time periods large volcanic influence, aerosol optical depth (AOD) surface concentration polluted generally vary anthropogenic emissions, but magnitude of this association can be dampened by presence natural aerosols, especially dust. Over...
Ambient fine particulate matter (PM2.5) is a leading environmental risk factor for premature mortality. We use aerosol optical depth (AOD) retrieved from two satellite instruments, MISR and SeaWiFS, to produce unified 15-year global time series (1998–2012) of ground-level PM2.5 concentration at resolution 1° x 1°. The GEOS-Chem chemical transport model (CTM) used relate each individual AOD retrieval PM2.5. Four broad areas showing significant, spatially coherent, annual trends are examined...
Abstract The Deep Blue (DB) algorithm has been used to retrieve aerosol optical depth (AOD) and Ångström exponent (AE) over land from multiple satellite instruments, including the Moderate Resolution Imaging Spectroradiometers (MODIS) aboard Terra Aqua platforms Visible Infrared Radiometer Suite (VIIRS). This study first validates latest MODIS (Collection 6.1) VIIRS (Version 1) DB data products against Aerosol Robotic Network observations. On global average, typical level of uncertainty in...
Abstract. We examine the distribution of aerosols and associated optical/radiative properties in Gangetic-Himalayan region from simultaneous radiometric measurements over Indo-Gangetic Plains (IGP) foothill/southern slopes Himalayas during 2009 pre-monsoon season. Enhanced dust transport extending Southwest Asian arid regions into IGP, results seasonal mean (April–June) aerosol optical depths 0.6 – highest Southern Asia. The influence loading is greater Western IGP as suggested by pronounced...
Abstract A primary goal of the Deep Blue (DB) project is to create consistent long‐term aerosol data records, suitable for climate studies, using multiple satellite instruments. In order continue Earth Observing System (EOS)‐era products into Joint Polar Satellite era, we have successfully ported DB algorithm process from Visible Infrared Imaging Radiometer Suite (VIIRS). Although basic structure VIIRS similar that Moderate Resolution Spectroradiometer (MODIS), many enhancements been made...
Abstract. Satellite instruments provide a vantage point for studying aerosol loading consistently over different regions of the world. However, typical lifetime single satellite platform is on order 5–15 years; thus, climate studies, use multiple sensors should be considered. Discrepancies exist between optical depth (AOD) products due to differences in their information content, spatial and temporal sampling, calibration, cloud masking, algorithmic assumptions. Users satellite-based AOD...
Abstract. Proven by multiple theoretical and practical studies, multi-angular spectral polarimetry is ideal for comprehensive retrieval of properties aerosols. Furthermore, a large number advanced space polarimeters have been launched recently or planned to be deployed in the coming few years (Dubovik et al., 2019). Nevertheless, at present, utilization aerosol products from rather limited, due relatively small polarimetric compared photometric observations, as well challenges making full...
A nearly 20‐year global data set (1979–1994 and 1996 to the present) of tropospheric absorbing aerosols has been developed from total ozone mapping spectrometer (TOMS) backscattered radiance measurements in range 331 380 nm. The occurrence is derived directly measured radiances represented by a quantity known as aerosol index. Previous theoretical model simulations have demonstrated that index depends on optical thickness (AOT), single scattering albedo, height AOT can be determined provided...
Measurements of the column‐integrated aerosol optical properties in southern African region were made by Aerosol Robotic Network (AERONET) Sun‐sky radiometers at several sites August–September 2000 as a part Southern Regional Science Initiative (SAFARI) dry season field campaign. Fine mode biomass burning aerosols dominated northern study (Zambia), which is an active region, and other including fossil fuel burning, industrial, aeolian coarse types also contributed to mixture regions (South...
The physical and optical properties of biomass burning aerosols in a savanna region south central Africa (Zambia) were analyzed from measurements made during the Zambian International Biomass Burning Emissions Experiment (ZIBBEE) August‐September 1997. Due to large spatial extent African savannas high frequency occurrence annual dry seasons, characterization resultant is important for study atmospheric radiative processes remote sensing both surface these regions. Aerosol Robotic Network...
Fundamental to the onset of Indian Summer Monsoon is land‐sea thermal gradient from Ocean Himalayas‐Tibetan Plateau (HTP). The timing strongly controlled by meridional tropospheric temperature due rapid pre‐monsoon heating HTP compared relatively cooler Ocean. Analysis temperatures longest available record microwave satellite measurements reveals widespread warming over Himalayan‐Gangetic region and consequent strengthening gradient. This trend most pronounced in season, resulting a 2.7°C...
A 14.5 year gridded data set of tropospheric absorbing aerosol index was derived from the Nimbus‐7 Total Ozone Mapping Spectrometer (TOMS) reflectivity difference between 340 and 380 nm channels. Based upon radiative transfer calculations, anomaly these two UV wavelength channels is very sensitive to smoke soot aerosols biomass burning forest fires, volcanic ash clouds as well desert mineral dust. We demonstrate ability TOMS instrument detect track generated by in South America. can clearly...
The Himalayas have a profound effect on the South Asian climate and regional hydrological cycle, as it forms barrier for strong monsoon winds serves an elevated heat source, thus controlling onset distribution of precipitation during Indian summer monsoon. Recent studies suggested that radiative heating by absorbing aerosols, such dust black carbon over Indo‐Gangetic Plains (IGP) slopes Himalayas, may significantly accelerate seasonal warming Hindu Kush–Himalayas–Tibetan Plateau (HKHT)...
Mineral dust interacts with radiation and impacts both the regional global climate. The relative contribution of natural anthropogenic sources, however, remains largely uncertain. Although human activities disturb soils therefore enhance wind erosion, their to emission has never been directly evaluated because a lack data. retrieval aerosol properties over land, including deserts, using Moderate Resolution Imaging Spectroradiometer Deep Blue algorithm makes first direct characterization...
The aerosol loading in south Asia has increased considerably because of the growing population, urbanization, and industrialization recent years. To understand effects aerosols on cloud properties this region, we have analyzed an extensive collection properties, obtained from Moderate resolution Imaging Spectroradiometer (MODIS) data, over Indian subcontinent during winter 2000–2006. During these months, Indo‐Gangetic (IG) plains, northern part India, are subjected to dense haze fog basis...