413 research outputs found
MLS and CALIOP Cloud Ice Measurements in the Upper Troposphere: A Constraint from Microwave on Cloud Microphysics
This study examines the consistency and microphysics assumptions among satellite ice water content (IWC) retrievals in the upper troposphere with collocated A-Train radiances from Microwave Limb Sounder (MLS) and lidar backscatters from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). For the cases in which IWC values are small (less than 10mg m(exp-23)), the cloud ice retrievals are constrained by both MLS 240- and 640- GHz radiances and CALIOP 532-nm backscatter beta(532). From the observed relationships between MLS cloud-induced radiance T(sub cir) and the CALIOP backscatter integrated gamma532 along the MLS line of sight, an empirical linear relation between cloud ice and the lidar backscatter is found: IWC/beta532=0.58+/-0.11. This lidar cloud ice relation is required to satisfy the cloud ice emission signals simultaneously observed at microwave frequencies, in which ice permittivity is relatively well known. This empirical relationship also produces IWC values that agree well with the CALIOP, version 3.0, retrieval at values, less than 10mg m(exp-3). Because the microphysics assumption is critical in satellite cloud ice retrievals, the agreement found in the IWC-beta532 relationships increase fidelity of the assumptions used by the lidar and microwave techniques for upper-tropospheric clouds
MLS and CALIOP Cloud Ice Measurements in the Upper Troposphere: A Constraint from Microwave on Cloud Microphysics
This study examines the consistency and microphysics assumptions among satellite ice water content (IWC) retrievals in the upper troposphere with collocated A-Train radiances from Microwave Limb Sounder (MLS) and lidar backscatters from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). For the cases in which IWC values are small (<10 mg m(-3)), the cloud ice retrievals are constrained by both MLS 240- and 640-GHz radiances and CALIOP 532-nm backscatter (532). From the observed relationships between MLS cloud-induced radiance T-cir and the CALIOP backscatter integrated (532) along the MLS line of sight, an empirical linear relation between cloud ice and the lidar backscatter is found: IWC/(532) = 0.58 +/- 0.11. This lidar cloud ice relation is required to satisfy the cloud ice emission signals simultaneously observed at microwave frequencies, in which ice permittivity is relatively well known. This empirical relationship also produces IWC values that agree well with the CALIOP, version 3.0, retrieval at values <10 mg m(-3). Because the microphysics assumption is critical in satellite cloud ice retrievals, the agreement found in the IWC-(532) relationships increase fidelity of the assumptions used by the lidar and microwave techniques for upper-tropospheric clouds
Digital image correlation techniques applied to LANDSAT multispectral imagery
The author has identified the following significant results. Automatic image registration and resampling techniques applied to LANDSAT data achieved accuracies, resulting in mean radial displacement errors of less than 0.2 pixel. The process method utilized recursive computational techniques and line-by-line updating on the basis of feedback error signals. Goodness of local feature matching was evaluated through the implementation of a correlation algorithm. An automatic restart allowed the system to derive control point coordinates over a portion of the image and to restart the process, utilizing this new control point information as initial estimates
Edge Artificial Intelligence for Real-Time Target Monitoring
The key enabling technology for the exponentially growing cellular communications sector is location-based services. The need for location-aware services has increased along with the number of wireless and mobile devices. Estimation problems, and particularly parameter estimation, have drawn a lot of interest because of its relevance and engineers' ongoing need for higher performance. As applications expanded, a lot of interest was generated in the accurate assessment of temporal and spatial properties.
In the thesis, two different approaches to subject monitoring are thoroughly addressed. For military applications, medical tracking, industrial workers, and providing location-based services to the mobile user community, which is always growing, this kind of activity is crucial.
In-depth consideration is given to the viability of applying the Angle of Arrival (AoA) and Receiver Signal Strength Indication (RSSI) localization algorithms in real-world situations. We presented two prospective systems, discussed them, and presented specific assessments and tests. These systems were put to the test in diverse contexts (e.g., indoor, outdoor, in water...). The findings showed the localization capability, but because of the low-cost antenna we employed, this method is only practical up to a distance of roughly 150 meters. Consequently, depending on the use-case, this method may or may not be advantageous. An estimation algorithm that enhances the performance of the AoA technique was implemented on an edge device.
Another approach was also considered. Radar sensors have shown to be durable in inclement weather and bad lighting conditions. Frequency Modulated Continuous Wave (FMCW) radars are the most frequently employed among the several sorts of radar technologies for these kinds of applications. Actually, this is because they are low-cost and can simultaneously provide range and Doppler data. In comparison to pulse and Ultra Wide Band (UWB) radar sensors, they also need a lower sample rate and a lower peak to average ratio. The system employs a cutting-edge surveillance method based on widely available FMCW radar technology. The data processing approach is built on an ad hoc-chain of different blocks that transforms data, extract features, and make a classification decision before cancelling clutters and leakage using a frame subtraction technique, applying DL algorithms to Range-Doppler (RD) maps, and adding a peak to cluster assignment step before tracking targets. In conclusion, the FMCW radar and DL technique for the RD maps performed well together for indoor use-cases. The aforementioned tests used an edge device and Infineon Technologies' Position2Go FMCW radar tool-set
Summaries of the Fifth Annual JPL Airborne Earth Science Workshop. Volume 3: AIRSAR Workshop
This publication is the third containing summaries for the Fifth Annual JPL Airborne Earth Science Workshop, held in Pasadena, California, on January 23-26, 1995. The main workshop is divided into three smaller workshops as follows: (1) The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) workshop, on January 23-24. The summaries for this workshop appear in Volume 1; (2) The Airborne synthetic Aperture Radar (AIRSAR) workshop, on January 25-26. The summaries for this workshop appear in this volume; and (3) The Thermal Infrared Multispectral Scanner (TIMS) workshop, on January 26. The summaries for this workshop appear in Volume 2
Co-located analysis of ice clouds detected from space and their impact on longwave energy transfer
A lack of quality data on high clouds has led to inadequate representations
within global weather and climate models. Recent advances in spaceborne
measurements of the Earth’s atmosphere have provided complementary
information on the interior of these clouds. This study demonstrate
how an array of space-borne measurements can be used and combined, by
close co-located comparisons in space and time, to form a more complete
representation of high cloud processes and properties.
High clouds are found in the upper atmosphere, where sub-zero temperatures
frequently result in the formation of cloud particles that are composed
of ice. Weather and climate models characterise the bulk properties
of these ice particles to describe the current state of the cloud-sky atmosphere.
By directly comparing measurements with simulations undertaken
at the same place and time, this study demonstrates how improvements can
be made to the representation of cloud properties. The results from this
study will assist in the design of future cloud missions to provide a better
quality input. These improvements will also help improve weather predictions
and lower the uncertainty in cloud feedback response to increasing
atmospheric temperature.
Most clouds are difficult to monitor by more than one instrument due
to continuous changes in: large-scale and sub-cloud scale circulation features,
microphysical properties and processes and characteristic chemical
signatures. This study undertakes co-located comparisons of high cloud
data with a cloud ice dataset reported from the Microwave Limb Sounder
(MLS) instrument onboard the Aura satellite that forms part of the A-train
constellation. Data from the MLS science team include vertical profiles of
temperature, ice water content (IWC) and the mixing ratios of several trace
gases. Their vertical resolutions are 3 to 6 km.
Initial investigations explore the link between cloud-top properties and
the longwave radiation budget, developing methods for estimating cloud
top heights using; longwave radiative fluxes, and IWC profiles. Synergistic
trios of direct and indirect high cloud measurements were used to validate
detections from the MLS by direct comparisons with two different
A-train instruments; the NASA Moderate-resolution Imaging Spectroradiometer
(MODIS) and the Clouds and the Earth’s Radiant Energy System
(CERES) onboard on the Aqua satellite. This finding focuses later
studies on two high cloud scene types that are well detected by the MLS;
deep convective plumes that form from moist ascent, and their adjacent
outflows that emanate outwards several hundred kilometres.
The second part of the thesis identifies and characterises two different
high cloud scenes in the tropics. Direct observational data is used to refine
calculations of the climate sensitivity to upper tropospheric humidity and
high cloud in different conditions. The data reveals several discernible
features of convective outflows are identified using a large sample of MLS
data. The key finding, facilitated by the use of co-location, reveals that
deep convective plumes exert a large longwave warming effect on the local
climate of 52 ± 28Wm−2, with their adjacent outflows presenting a more
modest warming of 33 ± 20Wm−2
Two Dimensional Positioning and Heading Solution for Flying Vehicles Using a Line-Scanning Laser Radar (LADAR)
Emerging technology in small autonomous flying vehicles requires the systems to have a precise navigation solution in order to perform tasks. In many critical environments, such as indoors, GPS is unavailable necessitating the development of supplemental aiding sensors to determine precise position. This research investigates the use of a line scanning laser radar (LADAR) as a standalone two dimensional position and heading navigation solution and sets up the device for augmentation into existing navigation systems. A fast histogram correlation method is developed to operate in real-time on board the vehicle providing position and heading updates at a rate of 10 Hz. LADAR navigation methods are adapted to 3 dimensions with a simulation built to analyze performance loss due attitude changes during flight. These simulations are then compared to experimental results collected using SICK LD-OEM 1000 mounted a cart traversing. The histogram correlation algorithm applied in this work was shown to successfully navigate a realistic environment where a quadrotor in short flights of less than 5 min in larger rooms. Application in hallways show great promise providing a stable heading along with tracking movement perpendicular to the hallway
Literature review of the remote sensing of natural resources
Abstracts of 596 documents related to remote sensors or the remote sensing of natural resources by satellite, aircraft, or ground-based stations are presented. Topics covered include general theory, geology and hydrology, agriculture and forestry, marine sciences, urban land use, and instrumentation. Recent documents not yet cited in any of the seven information sources used for the compilation are summarized. An author/key word index is provided
Space and Earth Science Data Compression Workshop
The workshop explored opportunities for data compression to enhance the collection and analysis of space and Earth science data. The focus was on scientists' data requirements, as well as constraints imposed by the data collection, transmission, distribution, and archival systems. The workshop consisted of several invited papers; two described information systems for space and Earth science data, four depicted analysis scenarios for extracting information of scientific interest from data collected by Earth orbiting and deep space platforms, and a final one was a general tutorial on image data compression
Space-Based Remote Sensing of the Earth: A Report to the Congress
The commercialization of the LANDSAT Satellites, remote sensing research and development as applied to the Earth and its atmosphere as studied by NASA and NOAA is presented. Major gaps in the knowledge of the Earth and its atmosphere are identified and a series of space based measurement objectives are derived. The near-term space observations programs of the United States and other countries are detailed. The start is presented of the planning process to develop an integrated national program for research and development in Earth remote sensing for the remainder of this century and the many existing and proposed satellite and sensor systems that the program may include are described
- …