Methods for Radiometric Cross-Calibration of Imaging Sensors With and Without Overlapping Collections

This slide presentation reviews methods of cross calibration for imaging sensors. Cross calibration methods fall under two categories: (1) Relies on knowledge of a source that is common to both sensors, (2) Typically near-coincident views. Some work has used methods that do not require simultaneous data collections. This talk discusses the International System of Units (SI) -traceable approaches that permit cross-calibration. It describes on-orbit cross-calibration methods that are typically used, with and without overlapping views. It reviews sample results. It also describes a method without overlapping views and without on-site measurements

Transmittance Measurement of a Heliostat Facility used in the Preflight Radiometric Calibration of Earth-Observing Sensors

Ball Aerospace and Technologies Corporation in Boulder, Colorado, has developed a heliostat facility that will be used to determine the preflight radiometric calibration of Earth-observing sensors that operate in the solar-reflective regime. While automatically tracking the Sun, the heliostat directs the solar beam inside a thermal vacuum chamber, where the sensor under test resides. The main advantage to using the Sun as the illumination source for preflight radiometric calibration is because it will also be the source of illumination when the sensor is in flight. This minimizes errors in the pre- and post-launch calibration due to spectral mismatches. It also allows the instrument under test to operate at irradiance values similar to those on orbit. The Remote Sensing Group at the University of Arizona measured the transmittance of the heliostat facility using three methods, the first of which is a relative measurement made using a hyperspectral portable spectroradiometer and well-calibrated reference panel. The second method is also a relative measurement, and uses a 12-channel automated solar radiometer. The final method is an absolute measurement using a hyperspectral spectroradiometer and reference panel combination, where the spectroradiometer is calibrated on site using a solar-radiation-based calibration

Dynamics of long gas bubbles rising in a vertical tube in a cocurrent liquid flow

© 2019 American Physical Society. When a confined long gas bubble rises in a vertical tube in a cocurrent liquid flow, its translational velocity is the result of both buoyancy and mean motion of the liquid. A thin film of liquid is formed on the tube wall and its thickness is determined by the interplay of viscous, inertial, capillary and buoyancy effects, as defined by the values of the Bond number (Bo≡ρgR2/σ with ρ being the liquid density, g the gravitational acceleration, R the tube radius, and σ the surface tension), capillary number (Cab≡μUb/σ with Ub being the bubble velocity and μ the liquid dynamic viscosity), and Reynolds number (Reb≡2ρUbR/μ). We perform experiments and numerical simulations to investigate systematically the effect of buoyancy (Bo=0-5) on the shape and velocity of the bubble and on the thickness of the liquid film for Cab=10-3-10-1 and Reb=10-2-103. A theoretical model, based on an extension of Bretherton's lubrication theory, is developed and utilized for parametric analyses; its predictions compare well with the experimental and numerical data. This study shows that buoyancy effects on bubbles rising in a cocurrent liquid flow make the liquid film thicker and the bubble rise faster, when compared to the negligible gravity case. In particular, gravitational forces impact considerably the bubble dynamics already when B

Calibration of the Thermal Infrared Sensor on the Landsat Data Continuity Mission

The Landsat series of satellites provides the longest running continuous data set of moderate-spatial-resolution imagery beginning with the launch of Landsat 1 in 1972 and continuing with the 1999 launch of Landsat 7 and current operation of Landsats 5 and 7. The Landsat Data Continuity Mission (LDCM) will continue this program into a fourth decade providing data that are keys to understanding changes in land-use changes and resource management. LDCM consists of a two-sensor platform comprised of the Operational Land Imager (OLI) and Thermal Infrared Sensors (TIRS). A description of the applications and design of the TIRS instrument is given as well as the plans for calibration and characterization. Included are early results from preflight calibration and a description of the inflight validation

Equine herpesvirus-2 E10 gene product, but not its cellular homologue, activates NF-kappaB transcription factor and c-Jun N-terminal kinase.

We have previously reported on the death effector domain containing E8 gene product from equine herpesvirus-2, designated FLICE inhibitory protein (v-FLIP), and on its cellular homologue, c-FLIP, which inhibit the activation of caspase-8 by death receptors. Here we report on the structure and function of the E10 gene product of equine herpesvirus-2, designated v-CARMEN, and on its cellular homologue, c-CARMEN, which contain a caspase-recruiting domain (CARD) motif. c-CARMEN is highly homologous to the viral protein in its N-terminal CARD motif but differs in its C-terminal extension. v-CARMEN and c-CARMEN interact directly in a CARD-dependent manner yet reveal different binding specificities toward members of the tumor necrosis factor receptor-associated factor (TRAF) family. v-CARMEN binds to TRAF6 and weakly to TRAF3 and, upon overexpression, potently induces the c-Jun N-terminal kinase (JNK), p38, and nuclear factor (NF)-kappaB transcriptional pathways. c-CARMEN or truncated versions thereof do not appear to induce JNK and NF-kappaB activation by themselves, nor do they affect the JNK and NF-kappaB activating potential of v-CARMEN. Thus, in contrast to the cellular homologue, v-CARMEN may have additional properties in its unique C terminus that allow for an autonomous activator effect on NF-kappaB and JNK. Through activation of NF-kappaB, v-CARMEN may regulate the expression of the cellular and viral genes important for viral replication

Opportunities to Intercalibrate Radiometric Sensors From International Space Station

Highly accurate measurements of Earth's thermal infrared and reflected solar radiation are required for detecting and predicting long-term climate change. We consider the concept of using the International Space Station to test instruments and techniques that would eventually be used on a dedicated mission such as the Climate Absolute Radiance and Refractivity Observatory. In particular, a quantitative investigation is performed to determine whether it is possible to use measurements obtained with a highly accurate reflected solar radiation spectrometer to calibrate similar, less accurate instruments in other low Earth orbits. Estimates of numbers of samples useful for intercalibration are made with the aid of year-long simulations of orbital motion. We conclude that the International Space Station orbit is ideally suited for the purpose of intercalibration

The EOS Prototype Validation Exercise (PROVE) at Jornada: Overview and Lessons Learned

The Earth Observing System (EOS) instrument teams must validate the operational products they produce from the Terra spacecraft data. As a pilot for future validation activities, four EOS teams (MODIS, MISR, ASTER, and Landsat-7) and community experts conducted an 11-day field campaign in May 1997 near Las Cruces, NM. The goals of the Prototype Validation Exercise (PROVE) included (1) gaining experience in the collection and use of field data for EOS product validation; (2) developing coordination, measurement, and data-archiving protocols; and (3) compiling a synoptic land and atmospheric data set for testing algorithms. PROVE was held at the USDA-Agricultural Research Service’s (ARS) Jornada Experimental Range, an expansive desert plateau hosting a complex mosaic of grasses and shrubs. Most macroscopic variables affecting the radiation environment were measured with ground, air-borne (including AVIRIS and laser altimeter), and space-borne sensors (including AVHRR, Landsat TM, SPOT, POLDER, and GOES). The Oak Ridge Distributed Active Archive Center (DAAC) then used campaign data sets to prototype Mercury, its Internet-based data harvesting and distribution system. This article provides general information about PROVE and assesses the progress made toward the campaign goals. Primary successes included the rapid campaign formulation and execution, measurement protocol development, and the significant collection, reduction, and sharing of data among participants. However, the PROVE data were used primarily for arid-land research and model validation rather than for validating satellite products, and the data were slow to reach the DAAC and hence public domain. The lessons learned included: (1) validation campaigns can be rapidly organized and implemented if there are focused objectives and on-site facilities and expertise; (2) data needs, organization, storage, and access issues must be addressed at the onset of campaign planning; and (3) the end-to-end data collection, release, and publication environment may need to be readdressed by program managers , funding agencies, and journal editors if rapid and comprehensive validation of operational satellite products is to occur

Inhibition of death receptor signals by cellular FLIP.

The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which can trigger apoptosis. However, Fas surface expression does not necessarily render cells susceptible to Fas ligand-induced death signals, indicating that inhibitors of the apoptosis-signalling pathway must exist. Here we report the characterization of an inhibitor of apoptosis, designated FLIP (for FLICE-inhibitory protein), which is predominantly expressed in muscle and lymphoid tissues. The short form, FLIPs, contains two death effector domains and is structurally related to the viral FLIP inhibitors of apoptosis, whereas the long form, FLIP(L), contains in addition a caspase-like domain in which the active-centre cysteine residue is substituted by a tyrosine residue. FLIPs and FLIP(L) interact with the adaptor protein FADD and the protease FLICE, and potently inhibit apoptosis induced by all known human death receptors. FLIP(L) is expressed during the early stage of T-cell activation, but disappears when T cells become susceptible to Fas ligand-mediated apoptosis. High levels of FLIP(L) protein are also detectable in melanoma cell lines and malignant melanoma tumours. Thus FLIP may be implicated in tissue homeostasis as an important regulator of apoptosis

Equations of Motion of Spinning Relativistic Particle in Electromagnetic and Gravitational Fields

We consider the motion of a spinning relativistic particle in external electromagnetic and gravitational fields, to first order in the external field, but to an arbitrary order in spin. The noncovariant spin formalism is crucial for the correct description of the influence of the spin on the particle trajectory. We show that the true coordinate of a relativistic spinning particle is its naive, common coordinate \r. Concrete calculations are performed up to second order in spin included. A simple derivation is presented for the gravitational spin-orbit and spin-spin interactions of a relativistic particle. We discuss the gravimagnetic moment (GM), a specific spin effect in general relativity. It is shown that for the Kerr black hole the gravimagnetic ratio, i.e., the coefficient at the GM, equals unity (just as for the charged Kerr hole the gyromagnetic ratio equals two). The equations of motion obtained for relativistic spinning particle in external gravitational field differ essentially from the Papapetrou equations.Comment: 32 pages, latex, Plenary talk at the Fairbank Meeting on the Lense--Thirring Effect, Rome-Pescara, 29/6-4/7 199

Studies of multiplicity in relativistic heavy-ion collisions

In this talk I'll review the present status of charged particle multiplicity measurements from heavy-ion collisions. The characteristic features of multiplicity distributions obtained in Au+Au collisions will be discussed in terms of collision centrality and energy and compared to those of p+p collisions. Multiplicity measurements of d+Au collisions at 200 GeV nucleon-nucleon center-of-mass energy will also be discussed. The results will be compared to various theoretical models and simple scaling properties of the data will be identified.Comment: "Focus on Multiplicity" Internationsl Workshop on Particle Multiplicity in Relativistic Heavy Ion Collisions, Bari, Italy, June 17-19, 2003, 16 pages, 15 figure