Institution
Jet Propulsion Laboratory
Facility•La Cañada Flintridge, California, United States•
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.
Topics: Mars Exploration Program, Telescope, Galaxy, Coronagraph, Planet
Papers published on a yearly basis
Papers
More filters
••
TL;DR: WASP-39b is a hot Saturn-mass exoplanet with a predicted clear atmosphere based on observations in the optical and infrared as mentioned in this paper, which is relatively high with respect to the currently established mass-metallicity trends.
Abstract: WASP-39b is a hot Saturn-mass exoplanet with a predicted clear atmosphere based on observations in the optical and infrared. Here, we complete the transmission spectrum of the atmosphere with observations in the near-infrared (NIR) over three water absorption features with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) G102 (0.8–1.1 μm) and G141 (1.1–1.7 μm) spectroscopic grisms. We measure the predicted high-amplitude H_2O feature centered at 1.4 μm and the smaller amplitude features at 0.95 and 1.2 μm, with a maximum water absorption amplitude of 2.4 planetary scale heights. We incorporate these new NIR measurements into previously published observational measurements to complete the transmission spectrum from 0.3 to 5 μm. From these observed water features, combined with features in the optical and IR, we retrieve a well constrained temperature T_(eq) = 1030_(-20)^(+30) K, and atmospheric metallicity 151_(-46)^(+48) x solar, which is relatively high with respect to the currently established mass–metallicity trends. This new measurement in the Saturn-mass range hints at further diversity in the planet formation process relative to our solar system giants.
164 citations
••
Ohio State University1, University of Massachusetts Amherst2, Intelligence and National Security Alliance3, United States Geological Survey4, University of California, Los Angeles5, University of Toulouse6, IM Flash Technologies7, Jet Propulsion Laboratory8, University of Bristol9, University of North Carolina at Chapel Hill10, Institut de Mathématiques de Toulouse11, Wilmington University12, Uppsala University13, Environment Canada14, PSL Research University15, University of Paris-Est16, University of Washington17, UNESCO-IHE Institute for Water Education18, Centre national de la recherche scientifique19, University of California, Irvine20
TL;DR: In this article, the authors evaluated the possibility of estimating discharge in ungauged rivers using synthetic, daily "remote sensing" measurements derived from hydraulic models corrupted with minimal observational errors, and found at least one algorithm able to estimate instantaneous discharge to within 35% relative root-mean-squared error (RRMSE) on 14/16 nonbraided rivers despite out-ofbank flows, multichannel planforms, and backwater effects.
Abstract: The Surface Water and Ocean Topography (SWOT) satellite mission planned for launch in 2020 will map river elevations and inundated area globally for rivers >100 m wide In advance of this launch, we here evaluated the possibility of estimating discharge in ungauged rivers using synthetic, daily ‘‘remote sensing’’ measurements derived from hydraulic models corrupted with minimal observational errors Five discharge algorithms were evaluated, as well as the median of the five, for 19 rivers spanning a range of hydraulic and geomorphic conditions Reliance upon a priori information, and thus applicability to truly ungauged reaches, varied among algorithms: one algorithm employed only global limits on velocity and depth, while the other algorithms relied on globally available prior estimates of discharge We found at least one algorithm able to estimate instantaneous discharge to within 35% relative root-mean-squared error (RRMSE) on 14/16 nonbraided rivers despite out-of-bank flows, multichannel planforms, and backwater effects Moreover, we found RRMSE was often dominated by bias; the median standard deviation of relative
residuals across the 16 nonbraided rivers was only 125% SWOT discharge algorithm progress is therefore encouraging, yet future efforts should consider incorporating ancillary data or multialgorithm synergy to improve results
164 citations
••
TL;DR: In this paper, the authors quantify the prospect of using emission lines from rotational transitions of the CO molecule to perform an "intensity mapping" observation at high redshift during the Epoch of Reionization (EoR).
Abstract: We quantify the prospects for using emission lines from rotational transitions of the CO molecule to perform an "intensity mapping" observation at high redshift during the Epoch of Reionization (EoR). The aim of CO intensity mapping is to observe the combined CO emission from many unresolved galaxies, to measure the spatial fluctuations in this emission, and to use this as a tracer of large-scale structure at very early times in the history of our universe. This measurement would help determine the properties of molecular clouds—the sites of star formation—in the very galaxies that reionize the universe. We further consider the possibility of cross-correlating CO intensity maps with future observations of the redshifted 21 cm line. The cross spectrum is less sensitive to foreground contamination than the auto power spectra, and can therefore help confirm the high-redshift origin of each signal. Furthermore, the cross spectrum measurement would help extract key information about the EoR, especially regarding the size distribution of ionized regions. We discuss uncertainties in predicting the CO signal at high redshift, and discuss strategies for improving these predictions. Under favorable assumptions and feasible specifications for a CO survey mapping the CO(2-1) and CO(1-0) lines, the power spectrum of CO emission fluctuations and its cross spectrum with future 21 cm measurements from the Murchison Widefield Array are detectable at high significance.
164 citations
••
TL;DR: The results show that both of these emissions are triggered by interplanetary shocks propagating outward from the Sun, which produces strong electric fields and therefore electron acceleration along the auroral field lines similar to the processes that occur during geomagnetic storms at the Earth.
Abstract: Radio emissions from Jupiter provided the first evidence that this giant planet has a strong magnetic field and a large magnetosphere. Jupiter also has polar aurorae, which are similar in many respects to Earth's aurorae. The radio emissions are believed to be generated along the high-latitude magnetic field lines by the same electrons that produce the aurorae, and both the radio emission in the hectometric frequency range and the aurorae vary considerably. The origin of the variability, however, has been poorly understood. Here we report simultaneous observations using the Cassini and Galileo spacecraft of hectometric radio emissions and extreme ultraviolet auroral emissions from Jupiter. Our results show that both of these emissions are triggered by interplanetary shocks propagating outward from the Sun. When such a shock arrives at Jupiter, it seems to cause a major compression and reconfiguration of the magnetosphere, which produces strong electric fields and therefore electron acceleration along the auroral field lines, similar to the processes that occur during geomagnetic storms at the Earth.
164 citations
••
TL;DR: Model calculations show that widespread severe denitrification could enhance future Arctic ozone loss by up to 30% and Polar stratospheric cloud lifetimes required for ArcticDenitrification to occur in the future are presented and contrasted against the current Antarctic cloudlifetimes.
Abstract: Upper Atmosphere Research Satellite observations indicate that extensive denitrification without significant dehydration currently occurs only in the Antarctic during mid to late June. The fact that denitrification occurs in a relatively warm month in the Antarctic raises concern about the likelihood of its occurrence and associated effects on ozone recovery in a colder and possibly more humid future Arctic lower stratosphere. Polar stratospheric cloud lifetimes required for Arctic denitrification to occur in the future are presented and contrasted against the current Antarctic cloud lifetimes. Model calculations show that widespread severe denitrification could enhance future Arctic ozone loss by up to 30%.
164 citations
Authors
Showing all 9033 results
Name | H-index | Papers | Citations |
---|---|---|---|
B. P. Crill | 148 | 486 | 111895 |
George Helou | 144 | 662 | 96338 |
H. K. Eriksen | 141 | 474 | 104208 |
Charles R. Lawrence | 141 | 528 | 104948 |
W. C. Jones | 140 | 395 | 97629 |
Gianluca Morgante | 138 | 478 | 98223 |
Jean-Paul Kneib | 138 | 805 | 89287 |
Kevin M. Huffenberger | 138 | 402 | 93452 |
Robert H. Brown | 136 | 1174 | 79247 |
Federico Capasso | 134 | 1189 | 76957 |
Krzysztof M. Gorski | 132 | 380 | 105912 |
Olivier Doré | 130 | 427 | 104737 |
Mark E. Thompson | 128 | 527 | 77399 |
Clive Dickinson | 123 | 501 | 80701 |
Daniel Stern | 121 | 788 | 69283 |