Publications by Jane Hurley


Seasonal evolution of Saturn's polar temperatures and composition

ICARUS 250 (2015) 131-153

LN Fletcher, PGJ Irwin, JA Sinclair, GS Orton, RS Giles, J Hurley, N Gorius, RK Achterberg, BE Hesman, GL Bjoraker


Analysis of Rosetta/VIRTIS spectra of earth using observations from ENVISAT/AATSR, TERRA/MODIS and ENVISAT/SCIAMACHY, and radiative-transfer simulations

PLANETARY AND SPACE SCIENCE 90 (2014) 37-59

J Hurley, PGJ Irwin, A Adriani, M Moriconi, F Oliva, F Capaccioni, A Smith, G Filacchione, F Tosi, G Thomas


Differentiability and retrievability of CO2 and H2O clouds on Mars from MRO/MCS measurements: A radiative-transfer study

PLANETARY AND SPACE SCIENCE 97 (2014) 65-84

J Hurley, NA Teanby, PGJ Irwin, SB Calcutt, E Sefton-Nash


Analysis of Rosetta/VIRTIS spectra of earth using observations from ENVISAT/AATSR, TERRA/MODIS and ENVISAT/SCIAMACHY, and radiative-transfer simulations

Planetary and Space Science 90 (2014) 37-59

J Hurley, PGJ Irwin, A Adriani, M Moriconi, F Oliva, F Capaccioni, A Smith, G Filacchione, F Tosi, G Thomas

Rosetta, the Solar System cornerstone mission of ESA's Horizon 2000 programme, consists of an orbiter and a lander, and is due to arrive at the comet 67P/Churyumov-Gerasimenko in May 2014. Following its 2004 launch, Rosetta carried out a series of planetary fly-bys and gravitational assists. On these close fly-bys of the Earth, measurements were taken by the Visible Infrared Thermal Imaging Spectrometer (VIRTIS). Analysis of these spectra and comparison with spectra acquired by Earth-observing satellites can support the verification of the inflight calibration of Rosetta/VIRTIS. In this paper, measurements taken by VIRTIS in November 2009 are compared with suitable coincident data from Earth-observing instruments (ESA-ENVISAT/AATSR and SCIAMACHY, and EOS-TERRA/MODIS). Radiative transfer simulations using NEMESIS (Irwin et al.; 2008) are fit to the fly-by data taken by VIRTIS, using representative atmospheric and surface parameters. VIRTIS measurements correlate 90% with AATSR's, 85-94% with MODIS, and 82-88% with SCIAMACHYs. The VIRTIS spectra are reproducible in the 1-5 μm region, except in the 1.4 μm deep water vapour spectral absorption band in the near-infrared in cases in which the radiance is very low (cloud-free topographies), where VIRTIS consistently registers more radiance than do MODIS and SCIAMACHY. Over these cloud-free regions, VIRTIS registers radiances a factor of 3-10 larger than SCIAMACHY and of 3-8 greater than MODIS. It is speculated that this discrepancy could be due to a spectral light leak originating from reflections from the order-sorting filters above the detector around 1.4 μm. © 2013 Elsevier Ltd.


Line-by-line analysis of Neptune's near-IR spectrum observed with Gemini/NIFS and VLT/CRIRES

ICARUS 227 (2014) 37-48

PGJ Irwin, E Lellouch, C de Bergh, R Courtin, B Bezard, LN Fletcher, GS Orton, NA Teanby, SB Calcutt, D Tice, J Hurley, GR Davis


From Voyager-IRIS to Cassini-CIRS: Interannual variability in Saturn's stratosphere?

ICARUS 233 (2014) 281-292

JA Sinclair, PGJ Irwin, LN Fletcher, T Greathouse, S Guerlet, J Hurley, C Merlet


Climatology and first-order composition estimates of mesospheric clouds from Mars Climate Sounder limb spectra

ICARUS 222 (2013) 342-356

E Sefton-Nash, NA Teanby, L Montabone, PGJ Irwin, J Hurley, SB Calcutt


Uranus' cloud particle properties and latitudinal methane variation from IRTF SpeX observations

ICARUS 223 (2013) 684-698

DS Tice, PGJ Irwin, LN Fletcher, NA Teanby, J Hurley, GS Orton, GR Davis


Seasonal variations of temperature, acetylene and ethane in Saturn's atmosphere from 2005 to 2010, as observed by Cassini-CIRS

ICARUS 225 (2013) 257-271

JA Sinclair, PGJ Irwin, LN Fletcher, JI Moses, TK Greathouse, AJ Friedson, B Hesman, J Hurley, C Merlet


Latitudinal variation of upper tropospheric NH3 on Saturn derived from Cassini/CIRS far-infrared measurements

Planetary and Space Science 73 (2012) 347-363

J Hurley, LN Fletcher, PGJ Irwin, SB Calcutt, JA Sinclair, C Merlet

Ammonia (NH 3 ) has been detected both on Saturn and Jupiter, and although its concentration and distribution has been well-studied on Jupiter, it has proven more difficult to do so on Saturn due to higher sensitivity requirements resulting from Saturn's lower atmospheric temperatures and the dominance of Saturn's phosphine which masks the ammonia signal. Using far-infrared measurements of Saturn taken by Cassini/CIRS between February 2005 and December 2010, the latitudinal variations of upper tropospheric ammonia on Saturn are studied. Sensitivity to NH 3 in the far-infrared is explored to provide estimates of temperature, para-H 2 and PH 3 , from 2.5 cm -1 spectral resolution measurements alone, 0.5 cm -1 spectral-resolution measurements alone, and 0.5 cm -1 measurements degraded to 2.5 cm -1 spectral resolution. The estimates of NH 3 from these three different datasets largely agree, although there are notable differences using the high emission angle 0.5 cm -1 data, which are asserted to result from a reduction in sensitivity at higher emission angles. For low emission angles, the 0.5 cm -1 -retrieved values of NH 3 can be used to reproduce the 2.5 cm -1 spectra with similar efficacy as those derived directly from the 2.5 cm -1 resolution data itself, and vice versa. Using low emission angle data, NH 3 is observed to have broad peak abundances at ±25°latitude, attributed to result from condensation and/or photolytic processes. Lack of data coverage at equatorial latitudes precludes analysis of NH 3 abundance at less than about 10°latitude. Noise levels are not sufficient to distinguish fine zonal features, although it seems that NH 3 cannot trace the zonal belt/zone structure in the upper troposphere of Saturn. © 2012 Elsevier Ltd. All rights reserved.


Fast cloud parameter retrievals of MIPAS/Envisat

ATMOSPHERIC CHEMISTRY AND PHYSICS 12 (2012) 7135-7164

R Spang, K Arndt, A Dudhia, M Hoepfner, L Hoffmann, J Hurley, RG Grainger, S Griessbach, C Poulsen, JJ Remedios, M Riese, H Sembhi, R Siddans, A Waterfall, C Zehner


The origin and evolution of Saturn's 2011-2012 stratospheric vortex

ICARUS 221 (2012) 560-586

LN Fletcher, BE Hesman, RK Achterberg, PGJ Irwin, G Bjoraker, N Gorius, J Hurley, J Sinclair, GS Orton, J Legarreta, E Garcia-Melendo, A Sanchez-Lavega, PL Read, AA Simon-Miller, FM Flasar


Observations of upper tropospheric acetylene on Saturn: No apparent correlation with 2000 km-sized thunderstorms

PLANETARY AND SPACE SCIENCE 65 (2012) 21-37

J Hurley, PGJ Irwin, LN Fletcher, JI Moses, B Hesman, J Sinclair, C Merlet


The application of new methane line absorption data to Gemini-N/NIFS and KPNO/FTS observations of Uranus' near-infrared spectrum

ICARUS 220 (2012) 369-382

PGJ Irwin, C de Bergh, R Courtin, B Bezard, NA Teanby, GR Davis, LN Fletcher, GS Orton, SB Calcutt, D Tice, J Hurley


Latitudinal variation of upper tropospheric NH3 on Saturn derived from Cassini/CIRS far-infrared measurements

PLANETARY AND SPACE SCIENCE 73 (2012) 347-363

J Hurley, LN Fletcher, PGJ Irwin, SB Calcutt, JA Sinclair, C Merlet


Further seasonal changes in Uranus' cloud structure observed by Gemini-North and UKIRT

ICARUS 218 (2012) 47-55

PGJ Irwin, NA Teanby, GR Davis, LN Fletcher, GS Orton, SB Calcutt, DS Tice, J Hurley


Observations of upper tropospheric acetylene on Saturn: No apparent correlation with 2000 km-sized thunderstorms

Planetary and Space Science 65 (2012) 21-37

J Hurley, PGJ Irwin, LN Fletcher, JI Moses, B Hesman, J Sinclair, C Merlet

Thunderstorm activity has been observed on Saturn via radio emissions from lightning discharges and optical detections of the lightning flashes on the planets nightside. Thunderstorms provide extreme environments in which specific atmospheric chemistry can be induced - namely through energy release via lightning discharges, and fast vertical transport resulting in rapid advection of tropospheric species. It is thus theorised that certain atmospheric trace species such as C 2 H 2 , HCN, and CO can be generated in the troposphere by large bursts of energy in the form of lightning, and transported upward towards the upper troposphere by the extreme dynamics of thunderstorms, where they should be observable by satellite instruments. In this work, high-spectral-resolution Cassini/CIRS observations from October 2005 through April 2009 are used to study whether there is an observable increase in upper tropospheric acetylene in regions of known normal thunderstorm activity. Using both individual measurements in which there is known thunderstorm activity, as well as large coadditions of data to study latitudinal-dependencies over the full disc, no systematic enhancement in upper tropospheric (100 mbar) C 2 H 2 was detected around regions in which there are known occurrences of normally sized (2000 km) thunderstorms, or in normally sized thunderstorm-prone regions such as 40°S. It is likely that the magnitude of the enhancement theorised is too generous or that enhancements are not advected into the upper troposphere as vertical mixing rates in models would suggest, since Cassini/CIRS can only detect C 2 H 2 above the 200 mbar level - although the massive northern hemisphere thunderstorm of 2010/2011 seems able to decrease stratospheric concentrations of C 2 H 2 . From this, it can be asserted that lightning from normal thunderstorm activity cannot be the key source for upper tropospheric C 2 H 2 on Saturn, since the upper-tropospheric concentrations retrieved agree with the concentrations stemming from the photolysis of CH 4 (23 ppbv) from solar radiation penetrating through the Saturnian atmosphere, with an upper limit for lightning-induced C 2 H 2 volume mixing ratio of 10 -9 . © 2012 Elsevier Ltd. All rights reserved.


Retrieval of macrophysical cloud parameters from MIPAS: algorithm description

ATMOSPHERIC MEASUREMENT TECHNIQUES 4 (2011) 683-704

J Hurley, A Dudhia, RG Grainger


Multispectral imaging observations of Neptune's cloud structure with Gemini-North

ICARUS 216 (2011) 141-158

PGJ Irwin, NA Teanby, GR Davis, LN Fletcher, GS Orton, D Tice, J Hurley, SB Calcutt


ORTIS - ORbiter terahertz infrared sounder

21st International Symposium on Space Terahertz Technology 2010, ISSTT 2010 (2010) 208-

BN Ellison, PGJ Irwin, SB Calcutt, S Rea, B Alderman, N Bowles, R Irshad, J Hurley

Accurate measurement of the temperature, composition and dynamics of Jupiter's atmosphere is one of the main scientific goals of ESA's and NASA's Outer Planet Mission proposals. Infrared remote sounding provides a powerful tool for achieving these objectives and was used by Voyager/IRIS and Cassini/CIRS, but is insensitive to some altitudes and gases. The sub-millimetre wavelength (terahertz) region of the electromagnetic spectrum, which has not been significantly exploited to date in the discipline of planetary science, provides unique spectral information over a range of atmospheric pressures and, when combined with infrared data, is a powerful in situ planetary atmospheric sounder. We will describe a novel low mass and low power consumption combined terahertz/IR instrument proposed for inclusion on the Jupiter Ganymede Orbiter that will greatly improve our understanding of the atmosphere of Jupiter. Through the combination of high spectral resolution 2.2THz spectroscopy (R=10 < sup > 6 < /sup > ) and lowspectral resolution IR radiometry, the entire temperature profile of the Jovian atmosphere from 0.6 to 10 < sup > -3 < /sup > bar can be evaluated (filling in the currently unmeasured levels between 0.1 and 0.01 bar). In addition, the tropospheric and stratospheric composition can be determined (especially water vapour) and observations of the Doppler shifting of sub-millimetre lines can also be used to measure horizontal wind speeds.

Pages