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At least 37 records · Page 2

Methods for Retrievals of CO2 Mixing Ratios from JPL Laser Absorption Spectrometer Flights During a Summer 2011 Campaign

The JPL airborne Laser Absorption Spectrometer instrument has been flown several times in the 2007-2011 time frame for the purpose of measuring CO2 mixing ratios in the lower atmosphere. This instrument employs CW laser transmitters and coherent detection receivers in the 2.05- micro m spectral region. The Integrated Path Differential Absorption (IPDA) method is used to retrieve weighted CO2 column mixing ratios. We present key features of the evolving LAS signal processing and data analysis algorithms and the calibration/validation methodology. Results from 2011 flights in various U.S. locations include observed mid-day CO2 drawdown in the Midwest and high spatial resolution plume detection during a leg downwind of the Four Corners power plant in New Mexico.

laser remote sensing↗

Sport Transition of JPSS VIIRS Imagery for Night-time Applications

The NASA/Short‐term Prediction, Research, and Transition (SPoRT) Program and NOAA/Cooperative Institute for Research in the Atmosphere (CIRA) work within the NOAA/Joint Polar Satellite System (JPSS) Proving Ground to demonstrate the unique capabilities of the VIIRS instrument. Very similar to MODIS, the VIIRS instrument provides many high‐resolution visible and infrared channels in a broad spectrum. In addition, VIIRS is equipped with a low‐light sensor that is able to detect light emissions from the land and atmosphere as well as reflected sunlight by the lunar surface. This band is referred to as the Day‐Night Band due to the sunlight being used at night to see cloud and topographic features just as one would typically see in day‐time visible imagery. NWS forecast offices that collaborate with SPoRT and CIRA have utilized MODIS imagery in operations, but have longed for more frequent passes of polar‐orbiting data. The VIIRS instrument enhances SPoRT collaborations with WFOs by providing another day and night‐time pass, and at times two additional passes due to its large swath width. This means that multi‐spectral, RGB imagery composites are more readily available to prepare users for their use in GOES‐R era and high‐resolution imagery for use in high‐latitudes is more frequently able to supplement standard GOES imagery within the SPoRT Hybrid GEO‐LEO product. The transition of VIIRS also introduces the new Day‐Night Band capability to forecast operations. An Intensive Evaluation Period (IEP) was conducted in Summer 2013 with a group of "Front Range" NWS offices related to VIIRS night‐time imagery. VIIRS single‐channel imagery is able to better analyze the specific location of fire hotspots and other land features, as well as provide a more true measurement of various cloud and aerosol properties than geostationary measurements, especially at night. Viewed within the SPoRT Hybrid imagery, the VIIRS data allows forecasters to better interpret the more frequent, but coarse GOES Imagery. Night‐time Microphysics and Dust RGB Imagery provides cloud analysis of cloud height, thickness, and composition in order for operational applications such as separating fog from low clouds, dust plume detection, and determining precipitating clouds in radar-void/ blocked regions. The Day‐Night Band has a particular benefit to seeing light from cities, fires, or other emissions as well as the reflection of moonlight off of clouds and smoke plumes, given the right lunar phase and angle. Examples from the VIIRS transition and IEP will be presented.

Fuell, Kevin↗

Relevance of ERTS to the State of Ohio

The author has identified the following significant results. The ability to delineate and inventory strip mined areas using ERTS-1 imagery has been established. This gives Ohio a method to rapidly gain an up-to-date inventory of strip mined lands for state planning purposes, which has not been available previously. Smoke plume detection and sedimentation patterns in Sandusky Bay have also been determined from initial analysis of ERTS-1 data.

Sweet, D. C.↗

Thermal Infrared Observations of Lava Flows During the 1984 Mauna Loa Eruption

Thermal infrared videotape images of the flowing lava streams and the vent areas at 10.6 microns were made, as well as some broadband images in the 8 to 12 micron range (for gas plume detection). These data were calibrated with on-site hand-held radiometer measurements, in-flow thermocouple measurements, and with later laboratory kiln measurements. Infrared video data are useful in quantitatively assessing the pattern and mode of flow thermal losses, particularly with regard to radiative losses from established/incipient floating crust. The general cooling of the flows downstream was readily apparent. Upper reaches of the active flow exhibited nearly crust-free main channels, radiating at about 700 to 800 degrees C. Below about the 7500 foot level (about 8 km from the vent) the flows formed nearly continuous crust and tended to spread, become less well-defined and founder due to a reduction in slope. Nevertheless, in thermal IR observations, the surface trace of the active subsurface channel was visible, radiating at about 500 to 700 degrees C. At the active flow front, most solid crust radiated at temperatures less than 500 to 600 degrees C, however bright high temperature interiors (approximately 900 to 1000 degrees C) were clearly visible though evolving fissures.

Pieri, D. C.↗

In situ observations in aircraft exhaust plumes in the lower stratosphere at midlatitudes

Instrumentation on the NASA ER-2 high-altitude aircraft has been used to observe engine exhaust from the same aircraft while operating in the lower stratosphere. Encounters with the exhaust plume occurred approximately 10 min after emission with spatial scales near 2 km and durations of up to 10 s. Measurements include total reactive nitrogen, NO(y), the component species NO and NO2, CO2, H2O, CO, N2O, condensation nuclei, and meteorological parameters. The integrated amounts of CO2 and H2O during the encounters are consistent with the stoichiometry of fuel combustion (1:1 molar). Emission indices (EI) for NO(x) (= NO + NO2), CO, and N2O are calculated using simultaneous measurements of CO2. EI values for NO(x) near 4 g/(kg fuel) are in good agreement with values scaled from limited ground-based tests of the ER-2 engine. Non-NO(x) species comprise less than about 20% of emitted reactive nitrogen, consistent with model evaluations. In addition to demonstrating the feasibility of aircraft plume detection, these results increase confidence in the projection of emissions from current and proposed supersonic aircraft fleets and hence in the assessment of potential long-term changes in the atmosphere.

Fahey, D. W.↗

Fragmentation of Comet Shoemaker-Levy 9's Nuclei During Flight Through the Jovian Atmosphere

Evidence on meteors and bolides shows that fragmentation is a major ablation process for all impactors penetrating the Earth's atmosphere, surpassing evaporation and fusion for impactors of the 'soft' cometary type. This model and data from plumes detected by the Hubble Space Telescope were used to estimate the size of the Shoemaker-Levy 9 nucleus.

comets meteors bolides Shoemaker-Levy↗

Plasmaspheric Structures Observed by the CLUSTER and IMAGE Spacecraft

Global EUV imaging observations by the IMAGE satellite have revealed spectacularly complex changes in plasmaspheric structures as the plasmaspheric plasmas respond to geomagnetic activity while remaining under varying degrees of influence by co-rotation, depending on the radial distance. This complex plasmaspheric plasma dynamics, with its numerous scales of variability, is clearly far from being well understood. There is now renewed interest in studying the plasmasphere due to its apparent connections with the development of the ring current and radiation belt and loss of ionospheric plasmas. Earlier in the mission, the Cluster spacecraft only crossed the plasmapause (L - 4) occasionally and made measurements of the cold plasma in the plasmasphere and plasmaspheric drainage plumes. The study by Darrouzet et al. [2006], for example, provided detailed analyses of in situ Cluster observations and IMAGE EUV imaging observations of three plasmaspheric plumes detected in April-June, 2002. Within the next couple of years, Cluster orbit will change, causing perigee to migrate to lower altitudes, and thus providing excellent opportunities to obtain more detailed measurements of the plasmasphere. In this paper, we report our analyses of the earlier Cluster-IMAGE events by incorporating the different perspectives provided by the IMAGE Radio Plasma Imager (RPI) observations through the plasmasphere. We will describe our new understanding of the Cluster-IMAGE events and their implications on plasmaspheric dynamics.

Fung, S. F.↗

Plasmaspheric Plumes Observed by the CLUSTER and IMAGE Spacecraft

Global IMAGE/EUV observations have revealed complex changes in plasmaspheric structures as the plasmasphere responds to geomagnetic activity while remaining under varying degrees of influence by co-rotation, depending on the radial distance. The complex plasmaspheric dynamics, with different scales of variability, is clearly far from being well understood. There is now renewed interest in the plasmasphere due to its apparent connections with the development of the ring current and radiation belt, and loss of ionospheric plasmas. Early in the mission, the Cluster spacecraft only crossed the plasmapause (L - 4) occasionally and made measurements of the outer plasmasphere and plasmaspheric drainage plumes. The study by Darrouzet et al. [2006] provided detailed analyses of in situ Cluster observations and IMAGE EUV observations of three plasmaspheric plumes detected in April-June, 2002. Within the next couple of years, Cluster orbit will change, causing perigee to migrate to lower altitudes, and thus providing excellent opportunities to obtain more detailed measurements of the plasmasphere. In this paper, we report our analyses of the earlier Cluster-IMAGE events by incorporating the different perspectives provided by the IMAGE Radio Plasma Imager (RPI) observations. We will discuss our new understanding of the structure and dynamics of the Cluster-IMAGE events.

Fung, S. F.↗

The Case for Enceladus Science

Enceladus has taken its place as one of the most remarkable moons in the solar system. When Voyager encountered Enceladus it was noted that its surface showed signs of recent activity with the observations of a large province, which was characterized by smooth sparsely cratered terrain. Even the heavily cratered areas of Enceladus showed a lower crater density than other Saturnian satellites. Moreover, its extraordinarily high albedo hinted at past cryovolcanic resurfacing events. Ground-based observations further demonstrated that Saturn's diffuse E-ring is concentrated at the orbit of EnceladLis, making the moon, the likely source of E-ring particles. However the short estimated lifetime of E-ring particles requires that new particles must constantly be fed to the Ering, implying more recent activity on Enceladus. Recently, in 2005 the Cassini spacecraft provided definitive proof that Enceladus is currently geologically active when multiple Cassini instruments detected plumes of gas and ice particles emanating from a series of warm fractures centered on the south pole, dubbed the "tiger stripes." Enceladus is the second cryovolcanically active icy satellite that has been identified (Triton is the only other known active icy satellite) and can be used to study active processes that are thought to have once played a role in shaping the surfaces of other icy satellites. These processes include tidal heating, cryovolcanism, and ice tectonism, which all can be studied as they currently happen on Enceladus, Moreover, the plume source region on Enceladus samples a warm, chemically rich, environment that may facilitate complex organic chemistry and biological processes. For these reasons, Enceladus science is highly relevant to NASA's goals.

Hurford, T. A.↗

High Ice Water Content Associated with a Darwin, Austrailia, Mesoscale Convective System

A mesoscale convective complex that occurred during the 2014 Darwin, Australia, flight campaign is examined via a three-dimensional, numerical simulation. The focus of the study is to better understand the presence and development of High Ice Water Content (HIWC) that was observed in the actual storm. Although peak values of ice water content may occur early in the storm lifetime, large areas of high concentrations expand with time and persist even when the storm tops begin to warm. The storm canopy which contains HIWC, has low radar reflectivity factor and is fed by an ensemble of regenerating thermal plumes. Detection via weather radar of the aviation hazard associated HIWC is challenging due the low values of radar reflectivity factor.

Aviation hazards↗

Observtion of Hunga Tonga Volcanic Eruption Using Hyperspectral Infrared Satellite Sensors

The Hunga Tonga-Hunga Ha'apai volcanic eruption, with the largest eruption occurred on 15 January 2022, injected unprecedented amounts of water vapor (H 2 O) and SO 2 to the stratosphere. Using the hyperspectral infrared sounder CrIS we present some unique features of the spectral near 9.6 µm and its great potential value for detecting plume or clouds with the tops above tropopause. It is found the existence of two umbrella clouds and the propagation of the upper plume even in 8-9 hour after the eruption. Using a new Single Field-of-view Sounder Atmospheric Products (SiFSAP) from CrIS and ATMS on JPSS-1 that has a high spatial resolution of about 14 km, this study analyzes the impact of Hunga Tonga eruption on the distribution of H 2 O and ozone, particularly the unprecedented ejection of water vapor in the stratosphere. These results demonstrate the value of hyperspectral infrared sounder and single-field-view products for monitoring the volcanic eruption and studying its impact to climate.

Xiaozhen Xiong↗

Observation of Hunga Tonga Volcanic Eruption Using Hyperspectral Infrared Satellite Sensors

The Hunga Tonga-Hunga Ha'apai volcanic eruption, with the largest eruption occurred on 15 January 2022, injected unprecedented amounts of water vapor (H 2 O) and SO 2 to the stratosphere. Using the hyperspectral infrared sounder CrIS we present some unique features of the spectral near 9.6 µm and its great potential value for detecting plume or clouds with the tops above tropopause. It is found the existence of two umbrella clouds and the propagation of the upper plume even in 8-9 hour after the eruption. Using a new Single Field-of-view Sounder Atmospheric Products (SiFSAP) from CrIS and ATMS on JPSS-1 that has a high spatial resolution of about 14 km, this study analyzes the impact of Hunga Tonga eruption on the distribution of H 2 O and ozone, particularly the unprecedented ejection of water vapor in the stratosphere. These results demonstrate the value of hyperspectral infrared sounder and single-field-view products for monitoring the volcanic eruption and studying its impact to climate.

Xiaozhen (Shawn) Xiong↗

Satellite detection of a long curving cirrus plume

On August 23, 1978, a long cirrus plume, as detected by the GOES E satellite, made a sharp anticyclonic turn and traveled a total distance of 2800 km from the generating thunderstorm, as determined from satellite imagery. During a five-hour period the leading edge moved a distance of 550 km, giving a speed of 30 m/sec. This is in good agreement with the pertinent wind speeds at the presumed height of the cloud, which may indicate that cirrus evaporation may not have been too important. In a relatively dense portion of the cirrus the minimum equivalent blackbody temperature was 226 K.

Wexler, R.↗

Submillimeter-wave properties of thermospheric rocket plumes

The problem of detecting rocket plumes at thermospheric altitudes with satellite-borne submillimeter-wave radiometers is examined theoretically. To estimate the sizes of plume signatures contrasted against a 250-K earth background or in self-emission against the cold sky, a computer program has been developed to predict plume brightness temperatures and optical depths of rotational lines of plume molecular constituents (e.g., H2O) as a function of distance from the nozzle. The methods employed in the computations are described in general terms, and examples are presented to indicate that detectable H2O signatures extending to several thousand nozzle diameters should exist at plume altitudes above 250 km.

Litvak, M. M.↗

Passive microwave detection of river-plume fronts in the German Bight

The NASA P-3 aircraft with the L- and S-band radiometer system on board participated in the MARSEN experiments carried out between August 30 and September 23, 1979. Measurements of surface temperature and salinity were concentrated on freshwater outflows of the Rivers Weser and Elbe in the German Bight. Three missions were carried out, on September 19, 22, and 23. The values of salinity are plotted as a function of geographic position, and contour maps of the salinity distribution are generated from the value plots. It is noted that on September 22, during a noon flood-tide, two river-plume salinity fronts were detected when a body of water with higher salinity existed in front of the Weser delta near Bremerhaven generating with the river outflow of lower saline waters a front of delta-S equals 5 per thousand. Another pocket of lower saline waters was found in front of the Elbe delta at Cuxhaven, which in turn set up a strong front of delta-S equals 6 per thousand. The morning low tide of September 23 did not exhibit this extreme condition.

Blume, H.-J. C.↗

Detection of Low-Lattitude Plumes in the Outer Corona by Ulysses Radio Ranging Measurements

Plumes have been detected beyond the field of view of coronagraphs in the range of 23-42 R(sub o) in an equatorial coronal hole by Ulysses radio ranging measurements conducted in 1991 at 13 and 3.6 cm wavelengths. These results show that plumes are not exclusive to polar regions, but appear to be intrinsic to open magnetic field regions at any latitude.

plumes white-light measurements inner corona open ↗

Sunglint-aided Methane Retrieval: Using Sentinel-2 to Quantify Offshore Oil and Gas Emissions

The extraction, production, and transportation of oil and gas via activities such as intentional venting and fugitive emissions are leading contributors to anthropogenic methane emissions. Offshore operations comprise a significant percentage of all oil and gas operations, yet emission monitoring over the ocean is insufficient. Due to low surface reflectance over the ocean, remote sensing measurements offshore are limited. Therefore offshore contributions to the overall global methane budget are unknown. Regulators such as the Bureau of Ocean and Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BSEE) are unable to validate operator-reported methane emission estimates. The NASA DEVELOP Program partnered with BOEM, BSEE, and SkyTruth to identify potential offshore methane sources in the Gulf of Mexico. Drawing upon existing retrieval methods to detect and quantify onshore methane emissions (Varon et al., 2021), we selected sunglint scenes to detect methane plumes over the ocean in Sentinel-2 imagery. We detected two methane plumes at the Constitution complex in the Gulf of Mexico and off the coast of Pointe-Noire, Congo. If expanded, these methods could serve a vital role in validating operator reporting and quantifying climate impacts of offshore oil and gas operations - complementing those of next generation satellites.

Katherine Howell↗