Jet Propulsion Laboratory

About: Jet Propulsion Laboratory is a facility organization based out in La Cañada Flintridge, California, United States. It is known for research contribution in the topics: Mars Exploration Program & Telescope. The organization has 8801 authors who have published 14333 publications receiving 548163 citations. The organization is also known as: JPL & NASA JPL.

In-flight performance and calibration of the Infrared Array Camera (IRAC) for the Spitzer Space Telescope

Abstract: The Infrared Array Camera (IRAC) is one of three focal plane instruments on board the Spitzer Space Telescope. IRAC is a four-channel camera that obtains simultaneous broad-band images at 3.6, 4.5, 5.8, and 8.0 μm in two nearly adjacent fields of view. We summarize here the in-flight scientific, technical, and operational performance of IRAC.

Hydrogen rich gas generator

Abstract: A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture, igniting the mixture to provide hot combustion gases, by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases present to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

Second and Third Season QUaD Cosmic Microwave Background Temperature and Polarization Power Spectra

Abstract: We report results from the second and third seasons of observation with the QUaD experiment. Angular power spectra of the cosmic microwave background are derived for both temperature and polarization at both 100 GHz and 150 GHz, and as cross-frequency spectra. All spectra are subjected to an extensive set of jackknife tests to probe for possible systematic contamination. For the implemented data cuts and processing technique such contamination is undetectable. We analyze the difference map formed between the 100 and 150 GHz bands and find no evidence of foreground contamination in polarization. The spectra are then combined to form a single set of results which are shown to be consistent with the prevailing LCDM model. The sensitivity of the polarization results is considerably better than that of any previous experiment—for the first time multiple acoustic peaks are detected in the E-mode power spectrum at high significance.

Observed latitudinal variations in erosion as a function of glacier dynamics.

Abstract: Erosion and velocity data from 15 outlet glaciers covering temperate to polar glacier thermal regimes from Patagonia to the Antarctic Peninsula reveal that over the past century the basin-averaged erosion rates vary by three orders of magnitude as a function of climate across this latitudinal transect. Glacial erosion plays an important role in shaping the Earth's landscape, but attempts to quantify the long-term effect of the erosion of glaciers have proven inclusive and contradictory. Glacial erosion rates are expected to decrease towards the poles, where lower temperatures limit meltwater production, thereby reducing glacial sliding, erosion and sediment transfer. This study presents erosion and velocity data from 15 outlet glaciers covering temperate to polar glacier thermal regimes from Patagonia to the Antarctic Peninsula. The dataset reveals that during the past century the basin-averaged erosion rates vary by three orders of magnitude as a function of climate across this latitudinal transect. The authors suggest that climate and the glacier thermal regime exert more control over erosion rates than the extent of ice cover, ice flux or sliding speeds. Glacial erosion is fundamental to our understanding of the role of Cenozoic-era climate change in the development of topography worldwide, yet the factors that control the rate of erosion by ice remain poorly understood. In many tectonically active mountain ranges, glaciers have been inferred to be highly erosive, and conditions of glaciation are used to explain both the marked relief typical of alpine settings and the limit on mountain heights above the snowline, that is, the glacial buzzsaw1. In other high-latitude regions, glacial erosion is presumed to be minimal, where a mantle of cold ice effectively protects landscapes from erosion2,3,4. Glacial erosion rates are expected to increase with decreasing latitude, owing to the climatic control on basal temperature and the production of meltwater, which promotes glacial sliding, erosion and sediment transfer. This relationship between climate, glacier dynamics and erosion rate is the focus of recent numerical modelling5,6,7,8, yet it is qualitative and lacks an empirical database. Here we present a comprehensive data set that permits explicit examination of the factors controlling glacier erosion across climatic regimes. We report contemporary ice fluxes, sliding speeds and erosion rates inferred from sediment yields from 15 outlet glaciers spanning 19 degrees of latitude from Patagonia to the Antarctic Peninsula. Although this broad region has a relatively uniform tectonic and geologic history, the thermal regimes of its glaciers range from temperate to polar. We find that basin-averaged erosion rates vary by three orders of magnitude over this latitudinal transect. Our findings imply that climate and the glacier thermal regime control erosion rates more than do extent of ice cover, ice flux or sliding speeds.