Tidal Power and Banding in Jupiter - NASA · number of new Juno observations, including the images...
6
Tidal Power and Banding in Jupiter Robert H. Tyler 1,2 1 Geodesy and Geophysics Lab, NASA GSFC , 2 Dept. Of Astronomy, University of Maryland Classical tidal theory (CTT) is used to estimate the rate at which tidal forces by the Galilean moons deposit energy in Jupiter’s interior, and the spatial distribution of the associated tidal dynamics. The energy deposition rate (power) is shown in Fig. 1 as a function of the non- dimensional dissipation time scale ( ! ") and non-dimensional squared wave speed ̃ $ % & . The subdomain expected for parameters of Jupiter’s upper atmosphere is shown in the dashed box and includes resonance peaks with power levels (when dimensionalized) high enough to explain part or all of Jupiter’s net emissions. A second important prediction from CTT is that there will be zones of dynamical banding and critical latitudes that appear consistent with a number of new Juno observations, including the images shown in Fig. 2. Fig. 1 Fig. 2 Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
Transcript of Tidal Power and Banding in Jupiter - NASA · number of new Juno observations, including the images...
Tidal Power and Banding in JupiterRobert H. Tyler1,2
1Geodesy and Geophysics Lab, NASA GSFC , 2Dept. Of Astronomy, University of Maryland
Classical tidal theory (CTT) is used to estimate the rate at which tidal forces by the Galilean moons deposit energy in Jupiter’s interior, and the spatial distribution of the associated tidal dynamics. The energy deposition rate (power) is shown in Fig. 1 as a function of the non-dimensional dissipation time scale ( !") and non-dimensional squared wave speed $̃%&. The subdomain expected for parameters of Jupiter’s upper atmosphere is shown in the dashed box and includes resonance peaks with power levels (when dimensionalized) high enough to explain part or all of Jupiter’s net emissions. A second important prediction from CTT is that there will be zones of dynamical banding and critical latitudes that appear consistent with a number of new Juno observations, including the images shown in Fig. 2.
Fig. 1 Fig. 2
Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
Name: Robert Tyler, Geodesy and Geophysics Lab, NASA GSFC E-mail: [email protected]: 301-614-6472
References:Tyler, R. H., 2018. Tidal Power and Banding in Jupiter. Planetary and Space Science, In press. (doi: 10.1016/j.pss.2018.10.002)
Data Sources: The associated paper in press is primarily theoretical but results are also compared with recently published visible (Junocam) and infrared (Jiram) observations from the Juno spacecraft. Other parameters used, as well as estimates of wave speeds in the interior, come from the literature base.
Technical Description of Figures:
Figure 1 Scenario space for non-dimensional tidal power (log$% scale with respect to 1 W/kg). The averaged tidal power (per unit mass) simultaneously describes the work performed on Jupiter by its moons and the dissipative heat generated. The power is shown as a function of the dimensionless dissipation time scale &' and the dimensionless squared wave speed )̃*+. Jupiter's tidal response is expected to include modes in the region enclosed by the dashed line and populated by resonance peaks. Dimensionalization and integration to obtain total tidal power depends of further assumptions, but general estimates show values that should be regarded as highly significant in Jupiter's energy budget. By contrast, the often assumed equilibrium tide response is unsupported by this study because unrealistically high internal wave speeds would be required.
Figure 2: Polar view of Jupiter. The governing equations predict tidal banding below the critical latitudes, poleward of which there is anabrupt change in dynamical behavior. The critical latitude depends rather specifically on the difference in the rates of Jupiter's rotation and the moon's orbit. The strong tides and banding due to Io's pull should occur only equatorward of ±50 degrees. The much weaker tidal pull of the other large moons allows weak tides and banding up to ± 77 degrees (the critical latitude associated with Callisto), poleward of which there should be no tidal bands. These theoretically predicted regimes appear supported by Juno observations, including the Junocam visible and Jiram infrared images shown (NASA/JPL-Caltech/SwRI/MSSS/Bjorn Jonsson).
Scientific significance, societal relevance, and relationships to future missions:
Understanding the tidal response of a planetary body is important as this determines the rate at which rotational/orbital energy is deposited in the interior. In addition, dynamical features predicted by tidal theory (such as banding and critical latitudes) can be usefully compared with observations to obtain constraints on interior parameters. Theory and observations support the view that Jupiter’s interior includes high-power, resonantly forced tidal oscillations and not the simple equilibrium tide response. An equilibrium tide response would require wave speeds of ~24,000 m/s in the interior to communicate the propagation of the pressure disturbace.
Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
Landsat 8 OLI & TIRS On-Orbit Radiometric Performance B. Markham, Biospheric Sciences, J. Barsi, SSAI, NASA GSFC; M. Montanaro, RIT
Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
1. The Landsat-8 Operational Land Imager (OLI) continues its record of remarkableradiometric stability over 5+ years. The CA band change is the largest at ~1.3% overthis period. All radiometric calibration techniques give consistent results within~0.5%. Some degradation is apparent in working stim lamp output.
2. The Landsat-8 Thermal Infrared Sensor (TIRS) is similarly extremely stable over themission, changing in response to the on-board blackbody by <0.5%. The stabilityhas allowed maintenance of the instrument calibration in spite of the need to reducecalibration data acquisition frequency due to scene select mirror encoder anomalies.
Figure 2: TIRS Radiometric Stability
Figure 1: OLI Coastal Aerosol (CA) Band Radiometric Stability
-0.4-0.3-0.2-0.10
0.1
0 1 2 3 4 5
ResponsivityChange[%]
TimeSinceLaunch[years]
TIRSResponsivityMetricascalculatedfromper-orbitcalibrationcollects
Band10bandaverage Band11bandaverage Electronicsswitch Sept2013safehold
Name: Brian L. Markham, Biospheric Sciences, NASA GSFC ; E-mail: [email protected], Phone: 301-614-6608
References:2018 Markham, B., Barsi, J., Montanaro, M., McCorkel, J., Gerace, A., Pedelty, J., Hook, S., Raqueno, N., Anderson, C. and Haque, Md Obaidul,
Landsat-8 On-orbit and Landsat-9 Pre-launch Sensor Radiometric Characterization, Proc. SPIE Asia Pacific Remote Sensing Conference, September 24-26, 2018, Honolulu, HI, 14 pp.
Technical Description of Images:Figure 1. The Landsat-8 OLI radiometric responsivity trends normalized to an early mission date. The coastal aerosol shows the largest changes of all the OLI bands, but are still less than 1.5% in responsivity.
Figure 2. The Landsat-8 TIRS radiometric responsivity trends normalized to an early mission date. On the primary electronics side (first 2 mission years) the response to the blackbody decreased 0.2% to 0.3%. On the secondary electronics side (after first 2 years), the response decreased 0.1% to 0.2%. Some portion of the change may relate to the blackbody as opposed to the instrument itself. About mission year 3, the operations concept was changed, with calibrations roughly twice a month versus twice an orbit.
Scientific significance, societal relevance and relationship to Decadal Survey: Inherent radiometric stability of remote sensing instruments as demonstrated by both the Landsat-8 OLI and TIRS, provides a strong basis for generating high quality consistent data products as are needed for detecting Earth surface changes over extended periods of time. This, combined with consistency between missions, which although not discussed here, has been part of the Landsat program for many years, provides Earth sciences the long term datasets they need.
Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
A first-of-its-kind, 30+ year, multivariate land reanalysis over the Continental U.S. (known as NCA-LDAS) that employs remotely sensed soil moisture, snow depth, snow cover and irrigation intensity estimates has been developed for the National Climate Assessment (NCA).
Drought indicators based on the NCA-LDAS demonstrate an increasing trend in average annual drought duration over the Southwest U.S., consistent with the patterns from the US Drought Monitor.
-50
0
50
100
150
200
250
1980 1985 1990 1995 2000 2005 2010 2015
NCA-LDASUSDM
Multivariate land reanalysis detects patterns of drought intensification in the Southwest U.S.
Sujay Kumar1, Mike Jasinski1, David Mocko1,3, Matthew Rodell1, Jordan Borak1,4, Bailing Li1,4, Hiroko Beaudoing1,4, Christa Peters-Lidard2
1Hydrological Sciences Laboratory, NASA/GSFC, 2Earth Science Division, NASA/GSFC, 3SAIC , 4ESSIC
Dro
ught
dur
atio
n (d
ays)
Southwest US
Name: Sujay V. Kumar, Hydrological Sciences Laboratory, NASA GSFCE-mail: [email protected]: 301-286-8663
References:Sujay V. Kumar, M. Jasinski, D. Mocko, M. Rodell, J. Borak, B. Li, H, Beaudoing, Christa D. Peters-Lidard, 2018. NCA-LDAS land analysis: Development and performance of a multisensory, multivariate land data assimilation system for the National Climate Assessment, J. Hydrometeor., doi:10.1175/JHM-D-17-0125.1.
Data Sources: Soil moisture retrievals from SMAP, SMOS, ASCAT, AMSR-E, SSM/I and SSMR, snow depth retrievals from AMSR2, AMSR-E, SSM/I, SMMR, snow cover retrievals from MODIS, irrigation intensity from MODIS, NLDAS-2 near surface forcing data available from the NASA GES DISC;
Technical Description of Figures:
Figure shows the time series of average drought duration (and their linear trendlines), computed on an annual basis from 1979to 2015 using NCA-LDAS root zone soil moisture estimates and that reported by the US Drought Monitor (USDM), for the Southwest U.S. The Figure indicates that there is an increasing trend in the average annual drought duration over the Southwest U.S., consistent with USDM.
Scientific significance, societal relevance, and relationships to future missions: NCA-LDAS represents one of the first successful examples of multisensor, multivariate land data assimilation, encompassing a large suite of remotely-sensing based soil moisture, snow depth, snow cover and irrigation intensity environmental data records. NCA-LDAS provides an end-to-end enabling tool for the water sector of the NCA, to develop an integrated water analysis that leverages latest advancements in terrestrial modeling, remote sensing and data assimilation. The evaluation of NCA-LDAS estimates indicates that multivariate assimilation of satellite remote sensing datasets is helpful toward improving the estimation of water budget estimates. The results also demonstrate that assimilation of data from more modern sensors such as SMAP produces more skillful results than the assimilation of data from older sensors. Drought indicators based on NCA-LDAS detect drought intensifications in the Western, U.S., consistent with the reported trends in the USDM. The capabilities demonstrated through NCA-LDAS will also be used in the next phase of the North American Land Data Assimilation System (NLDAS), which supports a variety of applications including drought assessment, flood risk estimation and weather/climate initialization.
Earth Sciences Division – Hydrosphere, Biosphere, and Geophysics
