scholarly journals Aerosol-induced radiative flux changes off the United States mid-Atlantic coast: Comparison of values calculated from sunphotometer and in situ data with those measured by airborne pyranometer

1999 ◽  
Vol 104 (D2) ◽  
pp. 2289-2307 ◽  
Author(s):  
P. B. Russell ◽  
J. M. Livingston ◽  
P. Hignett ◽  
S. Kinne ◽  
J. Wong ◽  
...  
Keyword(s):  
United States ◽  
Atlantic Coast ◽  
The United States ◽  
Radiative Flux ◽  
In Situ Data

scholarly journals Reconciling the differences between OMI-based and EPA AQS in situ NO<sub>2</sub> trends

2018 ◽  
Author(s):  
Ruixiong Zhang ◽  
Yuhang Wang ◽  
Charles Smeltzer ◽  
Hang Qu ◽  
William Koshak ◽  
...  
Keyword(s):  
United States ◽  
Trend Analysis ◽  
The United States ◽  
Lightning Flash ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
In Situ Data ◽  
Tropospheric No2 ◽  
Mean Trend

Abstract. With the improved spatial resolution than earlier instruments and more than ten years of service, tropospheric NO2 retrievals from the Ozone Monitoring Instrument (OMI) have led to many influential studies on the relationships between socioeconomic activities and NOx emissions. This study focuses on how to improve OMI NO2 retrievals for more reliable trend analysis. We retrieve OMI tropospheric NO2 vertical column densities (VCDs) and obtain the NO2 seasonal trends over the United States, which are compared with coincident in situ surface NO2 measurements from the Air Quality System (AQS) network. The Mann-Kendall method is applied to derive the NO2 seasonal and annual trends for four regions at coincident sites during 2005–2014. The OMI-based NO2 seasonal relative trends are generally biased high compared to the in situ trends by up to 3.7 % yr−1, except for the underestimation in the Midwest and Northeast during Dec–Jan–Feb (DJF). We improve the OMI retrievals for trend analysis by removing the ocean trend, using the MODerate-resolution Imaging Spectroradiometer (MODIS) albedo data in air mass factor (AMF) calculation, and applying a lightning flash filter to exclude lightning affected OMI NO2 retrievals. These improvements result in close agreement (within 0.3 % yr−1) between in situ and OMI-based NO2 regional annual relative trends. Thus, we recommend future studies to apply these procedures to ensure the quality of satellite-based NO2 trend analysis, especially in regions without reliable long-term in situ NO2 measurements. We derive optimized OMI-based NO2 regional annual relative trends using all available data for the West (−2.0 % ± 0.3 yr−1), the Midwest (−1.8 % ± 0.4 yr−1), the Northeast (−3.1 % ± 0.5 yr−1), and the South (−0.9 % ± 0.3 yr−1). The OMI-based annual mean trend over the contiguous United States is −1.5 % ± 0.2 yr−1. It is a factor of 2 lower than that of the AQS in situ data (−3.9 % ± 0.4 yr−1); the difference is mainly due to the fact that the locations of AQS sites are concentrated in urban and suburban regions.

Identification of Marine Hydrates In Situ and Their Distribution off the Atlantic Coast of the United States

1994 ◽  
Vol 715 (1 Natural Gas H) ◽  
pp. 364-380 ◽  
Author(s):  
WILLIAM P. DILLON ◽  
MYUNG W. LEE ◽  
DWIGHT F. COLEMAN
Keyword(s):  
United States ◽  
Atlantic Coast ◽  
The United States

scholarly journals Assessment of NO<sub>2</sub> observations during DISCOVER-AQ and KORUS-AQ field campaigns

2020 ◽  
Vol 13 (5) ◽  
pp. 2523-2546 ◽  
Author(s):  
Sungyeon Choi ◽  
Lok N. Lamsal ◽  
Melanie Follette-Cook ◽  
Joanna Joiner ◽  
Nickolay A. Krotkov ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
A Priori ◽  
Reduction Process ◽  
Remote Sensing Data ◽  
The United States ◽  
Environmental Research ◽  
Ozone Monitoring Instrument ◽  
In Situ Data

Abstract. NASA's Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ, conducted in 2011–2014) campaign in the United States and the joint NASA and National Institute of Environmental Research (NIER) Korea–United States Air Quality Study (KORUS-AQ, conducted in 2016) in South Korea were two field study programs that provided comprehensive, integrated datasets of airborne and surface observations of atmospheric constituents, including nitrogen dioxide (NO2), with the goal of improving the interpretation of spaceborne remote sensing data. Various types of NO2 measurements were made, including in situ concentrations and column amounts of NO2 using ground- and aircraft-based instruments, while NO2 column amounts were being derived from the Ozone Monitoring Instrument (OMI) on the Aura satellite. This study takes advantage of these unique datasets by first evaluating in situ data taken from two different instruments on the same aircraft platform, comparing coincidently sampled profile-integrated columns from aircraft spirals with remotely sensed column observations from ground-based Pandora spectrometers, intercomparing column observations from the ground (Pandora), aircraft (in situ vertical spirals), and space (OMI), and evaluating NO2 simulations from coarse Global Modeling Initiative (GMI) and high-resolution regional models. We then use these data to interpret observed discrepancies due to differences in sampling and deficiencies in the data reduction process. Finally, we assess satellite retrieval sensitivity to observed and modeled a priori NO2 profiles. Contemporaneous measurements from two aircraft instruments that likely sample similar air masses generally agree very well but are also found to differ in integrated columns by up to 31.9 %. These show even larger differences with Pandora, reaching up to 53.9 %, potentially due to a combination of strong gradients in NO2 fields that could be missed by aircraft spirals and errors in the Pandora retrievals. OMI NO2 values are about a factor of 2 lower in these highly polluted environments due in part to inaccurate retrieval assumptions (e.g., a priori profiles) but mostly to OMI's large footprint (>312 km2).

scholarly journals Assessment of NO<sub>2</sub> observations during DISCOVER-AQ and KORUS-AQ field campaigns

2019 ◽  
Author(s):  
Sungyeon Choi ◽  
Lok N. Lamsal ◽  
Melanie Follette-Cook ◽  
Joanna Joiner ◽  
Nickolay A. Krotkov ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
A Priori ◽  
Reduction Process ◽  
Remote Sensing Data ◽  
The United States ◽  
Environmental Research ◽  
Ozone Monitoring Instrument ◽  
In Situ Data

Abstract. NASA’s Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaign in the United States and the joint NASA and National Institute of Environmental Research (NIER) Korea-United States Air Quality Study (KORUS-AQ) in South Korea were two field study programs that provided comprehensive, integrated datasets of airborne and surface observations of atmospheric constituents, including nitrogen dioxide (NO2), with a goal of improving the interpretation of spaceborne remote sensing data. Various types of NO2 measurements were made, including in situ concentrations and column amounts of NO2 using ground- and aircraft-based instruments, while NO2 column amounts were being derived from the Ozone Monitoring Instrument (OMI) on the Aura satellite. This study takes advantage of these unique data sets by first evaluating in situ data taken from two different instruments on the same aircraft platform, comparing coincidently sampled profile-integrated columns from aircraft spirals with remotely sensed column observations from ground-based Pandora spectrometers, intercomparing column observations from the ground (Pandora), aircraft (in situ vertical spirals), and space (OMI), and evaluating NO2 simulations from coarse Global Modeling Initiative (GMI) and high-resolution regional models. We then use these data to interpret observed discrepancies due to differences in sampling and deficiencies in the data reduction process. Finally, we assess satellite retrieval sensitivity to observed and modeled a-priori NO2 profiles. Contemporaneous measurements from two aircraft instruments that likely sample similar air masses generally agree very well but are also found to differ in integrated columns by up to 33.3 %. These show even larger differences with Pandora, reaching up to 53.1 %, potentially due to a combination of strong gradients in NO2 fields that could be missed by aircraft spirals and errors in the Pandora retrievals. OMI NO2 values are about a factor of two lower in these highly polluted environments, due in part to inaccurate retrieval assumptions (e.g., a priori profiles), but mostly to OMI’s areal (> 312 km2) averaging.

scholarly journals International Arctic Systems for Observing the Atmosphere: An International Polar Year Legacy Consortium

2016 ◽  
Vol 97 (6) ◽  
pp. 1033-1056 ◽  
Author(s):  
Taneil Uttal ◽  
Sandra Starkweather ◽  
James R. Drummond ◽  
Timo Vihma ◽  
Alexander P. Makshtas ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Satellite Observations ◽  
The Arctic ◽  
International Polar Year ◽  
Network Measurements ◽  
International Polar ◽  
In Situ Observations ◽  
Arctic Atmosphere

Abstract International Arctic Systems for Observing the Atmosphere (IASOA) activities and partnerships were initiated as a part of the 2007–09 International Polar Year (IPY) and are expected to continue for many decades as a legacy program. The IASOA focus is on coordinating intensive measurements of the Arctic atmosphere collected in the United States, Canada, Russia, Norway, Finland, and Greenland to create synthesis science that leads to an understanding of why and not just how the Arctic atmosphere is evolving. The IASOA premise is that there are limitations with Arctic modeling and satellite observations that can only be addressed with boots-on-the-ground, in situ observations and that the potential of combining individual station and network measurements into an integrated observing system is tremendous. The IASOA vision is that by further integrating with other network observing programs focusing on hydrology, glaciology, oceanography, terrestrial, and biological systems it will be possible to understand the mechanisms of the entire Arctic system, perhaps well enough for humans to mitigate undesirable variations and adapt to inevitable change.

scholarly journals Genomics, Exometabolomics, and Metabolic Probing Reveal Conserved Proteolytic Metabolism of Thermoflexus hugenholtzii and Three Candidate Species From China and Japan

2021 ◽  
Vol 12 ◽  
Author(s):  
Scott C. Thomas ◽  
Devon Payne ◽  
Kevin O. Tamadonfar ◽  
Cale O. Seymour ◽  
Jian-Yu Jiao ◽  
...  
Keyword(s):  
United States ◽  
Amino Acids ◽  
Draft Genome ◽  
The United States ◽  
Pentose Phosphate ◽  
High Abundance ◽  
Comparative Genomic ◽  
Labeled Compounds ◽  
Geothermal Systems

Thermoflexus hugenholtzii JAD2T, the only cultured representative of the Chloroflexota order Thermoflexales, is abundant in Great Boiling Spring (GBS), NV, United States, and close relatives inhabit geothermal systems globally. However, no defined medium exists for T. hugenholtzii JAD2T and no single carbon source is known to support its growth, leaving key knowledge gaps in its metabolism and nutritional needs. Here, we report comparative genomic analysis of the draft genome of T. hugenholtzii JAD2T and eight closely related metagenome-assembled genomes (MAGs) from geothermal sites in China, Japan, and the United States, representing “Candidatus Thermoflexus japonica,” “Candidatus Thermoflexus tengchongensis,” and “Candidatus Thermoflexus sinensis.” Genomics was integrated with targeted exometabolomics and 13C metabolic probing of T. hugenholtzii. The Thermoflexus genomes each code for complete central carbon metabolic pathways and an unusually high abundance and diversity of peptidases, particularly Metallo- and Serine peptidase families, along with ABC transporters for peptides and some amino acids. The T. hugenholtzii JAD2T exometabolome provided evidence of extracellular proteolytic activity based on the accumulation of free amino acids. However, several neutral and polar amino acids appear not to be utilized, based on their accumulation in the medium and the lack of annotated transporters. Adenine and adenosine were scavenged, and thymine and nicotinic acid were released, suggesting interdependency with other organisms in situ. Metabolic probing of T. hugenholtzii JAD2T using 13C-labeled compounds provided evidence of oxidation of glucose, pyruvate, cysteine, and citrate, and functioning glycolytic, tricarboxylic acid (TCA), and oxidative pentose-phosphate pathways (PPPs). However, differential use of position-specific 13C-labeled compounds showed that glycolysis and the TCA cycle were uncoupled. Thus, despite the high abundance of Thermoflexus in sediments of some geothermal systems, they appear to be highly focused on chemoorganotrophy, particularly protein degradation, and may interact extensively with other microorganisms in situ.

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