169 research outputs found
Value stream mapping for sustainable change at a Swedish dairy farm
This case study increases our understanding of Lean implementation in which value stream mapping (VSM) is used to create an action plan at a small dairy and cattle farm in southwest Sweden. The researchers, the farmer-owner, and farm employees followed a step-by-step approach that resulted in ideas for operational improvements for the dairy activity. Data were collected in interviews with the farmer/owner, researcher participation in workshops, and researcher observations. The results reveal that VSM is an effective way to create a culture of collaboration among the farm staff and to better define their roles and responsibilities as well as improve routines, communications, and task completion. In the two-to-three year period following the VSM project, specific improvements were observed in milk production/quality and animal health. The results also reveal that while Lean principles are relevant given the repetitive nature of agriculture routines and tasks, the VSM element of lead-time reduction is less relevant owing to the unique value adding biological processes in the agriculture sector
Detection of the infrared aurora at Uranus with Keck-NIRSPEC
Near infrared (NIR) wavelength observations of Uranus have been unable to
locate any infrared aurorae, despite many attempts to do so since the 1990s.
While at Jupiter and Saturn, NIR investigations have redefined our
understanding of magnetosphere ionosphere thermosphere coupling, the lack of
NIR auroral detection at Uranus means that we have lacked a window through
which to study these processes at Uranus. Here we present NIR Uranian
observations with the Keck II telescope taken on the 5 September 2006 and
detect enhanced emissions. Analysing
temperatures and column densities, we identify an 88\% increase in localized
column density, with no significant
temperature increases, consistent with auroral activity generating increased
ionization. By comparing these structures against the
magnetic field model and the Voyager 2
ultraviolet observations, we suggest that these regions make up sections of the
northern aurora.Comment: 12 pages, 3 main figures, 2 extended data figures. Nat Astron (2023
Ground-based observations of Saturn’s auroral ionosphere over three days:trends in H3+ temperature, density and emission with Saturn local time and planetary period oscillation
On 19–21 April 2013, the ground-based 10-m W.M. Keck II telescope was used to simultaneously measure View the MathML sourceH3+ emissions from four regions of Saturn’s auroral ionosphere: (1) the northern noon region of the main auroral oval; (2) the northern midnight main oval; (3) the northern polar cap and (4) the southern noon main oval. The View the MathML sourceH3+ emission from these regions was captured in the form of high resolution spectral images as the planet rotated. The results herein contain twenty-three View the MathML sourceH3+ temperatures, column densities and total emissions located in the aforementioned regions – ninety-two data points in total, spread over timescales of both hours and days. Thermospheric temperatures in the spring-time northern main oval are found to be cooler than their autumn-time southern counterparts by tens of K, consistent with the hypothesis that the total thermospheric heating rate is inversely proportional to magnetic field strength. The main oval View the MathML sourceH3+ density and emission is lower at northern midnight than it is at noon, in agreement with a nearby peak in the electron influx in the post-dawn sector and a minimum flux at midnight. Finally, when arranging the northern main oval View the MathML sourceH3+ parameters as a function of the oscillation period seen in Saturn’s magnetic field – the planetary period oscillation (PPO) phase – we see a large peak in View the MathML sourceH3+ density and emission at ∼115° northern phase, with a full-width at half-maximum (FWHM) of ∼44°. This seems to indicate that the influx of electrons associated with the PPO phase at 90° is responsible at least in part for the behavior of all View the MathML sourceH3+ parameters. A combination of the View the MathML sourceH3+ production and loss timescales and the ±10° uncertainty in the location of a given PPO phase are likely, at least in part, to be responsible for the observed peaks in View the MathML sourceH3+ density and emission occurring at a later time than the peak precipitation expected at 90° PPO phase
Cassini observations of ionospheric plasma in Saturn's magnetotail lobes
Studies of Saturn's magnetosphere with the Cassini mission have established the importance of Enceladus as the dominant mass source for Saturn's magnetosphere. It is well known that the ionosphere is an important mass source at Earth during periods of intense geomagnetic activity but lesser attention has been dedicated to study the ionospheric mass source at Saturn. In this paper we describe a case study of data from Saturn's magnetotail, when Cassini was located at ∼2200 hours Saturn local time at 36 RS from Saturn. During several entries into the magnetotail lobe, tailward-flowing cold electrons and a cold ion beam were observed directly adjacent to the plasma sheet and extending deeper into the lobe. The electrons and ions appear to be dispersed, dropping to lower energies with time. The composition of both the plasma sheet and lobe ions show very low fluxes (sometimes zero within measurement error) of water group ions. The magnetic field has a swept-forward configuration which is atypical for this region and the total magnetic field strength larger than expected at this distance from the planet. Ultraviolet auroral observations show a dawn brightening and upstream heliospheric models suggest that the magnetosphere is being compressed by a region of high solar wind ram pressure. We interpret this event as the observation of ionospheric outflow in Saturn's magnetotail. We estimate a number flux between 2.95±0.43×109 1.43±0.21×1010 cm-2 s-1, one or about two orders magnitude larger than suggested by steady state MHD models, with a mass source between 1.4×102 and 1.1×103 kg/s. After considering several configurations for the active atmospheric regions, we consider as most probable the main auroral oval, with associated mass source between 49.7±13.4 and 239.8±64.8 kg/s for an average auroral oval, and 10±4 and 49±23 kg/s for the specific auroral oval morphology found during this event. It is not clear how much of this mass is trapped within the magnetosphere and how much is lost to the solar wind
Investigating Thermal Contrasts Between Jupiter's Belts, Zones, and Polar Vortices with VLT/VISIR
Using images at multiple mid-infrared wavelengths, acquired in May 2018 using
the VISIR instrument on ESO's Very Large Telescope (VLT), we study Jupiter's
pole-to-pole thermal, chemical and aerosol structure in the troposphere and
stratosphere. We confirm that the pattern of cool and cloudy anticyclonic zones
and warm cloud-free cyclonic belts persists throughout the mid-latitudes, up to
the polar boundaries, and evidence a strong correlation with the vertical
maximum windshear and the locations of Jupiter's zonal jets. At high latitudes,
VISIR images reveal a large region of mid-infrared cooling poleward
64N and 67S extending from the upper
troposphere to the stratosphere, co-located with the reflective aerosols
observed by JunoCam, and suggesting that aerosols play a key role in the
radiative cooling at the poles. Comparison of zonal-mean thermal properties and
high-resolution visible imaging from Juno allows us to study the variability of
atmospheric properties as a function of altitude and jet boundaries,
particularly in the cold southern polar vortex. However, the southern
stratospheric polar vortex is partly masked by a warm mid-infrared signature of
the aurora. Co-located with the southern main auroral oval, this warming
results from the auroral precipitation and/or joule heating which heat the
atmosphere and thus cause a significant stratospheric emission. This high
emission results from a large enhancement of both ethane and acetylene in the
polar region, reinforcing the evidence of enhanced ion-related chemistry in
Jupiter's auroral regions
Saturn's Seasonal Variability from Four Decades of Ground-Based Mid-Infrared Observations
A multi-decade record of ground-based mid-infrared (7-25 m) images of
Saturn is used to explore seasonal and non-seasonal variability in thermal
emission over more than a Saturnian year (1984-2022). Thermal emission measured
by 3-m and 8-m-class observatories compares favourably with synthetic images
based on both Cassini-derived temperature records and the predictions of
radiative climate models. 8-m class facilities are capable of resolving thermal
contrasts on the scale of Saturn's belts, zones, polar hexagon, and polar
cyclones, superimposed onto large-scale seasonal asymmetries. Seasonal changes
in brightness temperatures of K in the stratosphere and K in
the upper troposphere are observed, as the northern and southern polar
stratospheric vortices (NPSV and SPSV) form in spring and dissipate in autumn.
The timings of the first appearance of the warm polar vortices is successfully
reproduced by radiative climate models, confirming them to be radiative
phenomena, albeit entrained within sharp boundaries influenced by dynamics.
Axisymmetric thermal bands (4-5 per hemisphere) display temperature gradients
that are strongly correlated with Saturn's zonal winds, indicating winds that
decay in strength with altitude, and implying meridional circulation cells
forming the system of cool zones and warm belts. Saturn's thermal structure is
largely repeatable from year to year (via comparison of infrared images in 1989
and 2018), with the exception of low-latitudes. Here we find evidence of
inter-annual variations because the equatorial banding at 7.9 m is
inconsistent with a -year period for Saturn's equatorial stratospheric
oscillation, i.e., it is not strictly semi-annual. Finally, observations
between 2017-2022 extend the legacy of the Cassini mission, revealing the
continued warming of the NPSV during northern summer. [Abr.]Comment: 25 pages, 15 figures, accepted for publication in Icaru
Cassini VIMS observations of H3+ emission on the nightside of Jupiter
We present the first detailed analysis of H3+ nightside emission from Jupiter, using Visual and Infrared Mapping Spectrometer (VIMS) data from the Cassini flyby in 2000–2001, producing the first Jovian maps of nightside H3+ emission, temperature, and column density. Using these, we identify and characterize regions of H3+ nightside emission, compared against past observations of H3+ emission on the dayside. We focus our investigation on the region previously described as “mid-to-low latitude emission,” the source for which has been controversial. We find that the brightest of this emission is generated at Jovigraphic latitudes similar to the most equatorward extent of the main auroral emission but concentrated at longitudes eastward of this emission. The emission is produced by enhanced H3+ density, with temperatures dropping away in this region. This emission has a loose association with the predicted location of diffuse aurora produced by pitch angle scattering in the north, but not in the south. This emission also lays in the path of subrotating winds flowing from the aurora, suggesting a transport origin. Some differences are seen between dayside and nightside subauroral emissions, with dayside emission extending more equatorward, perhaps caused by the lack of sunlight ionization on the nightside, and unmeasured changes in temperature. Ionospheric temperatures are hotter in the polar region (~1100–1500 K), dropping away toward the equator (as low as 750 K), broadly similar to values on the dayside, highlighting the dominance of auroral effects in the polar region. No equatorial emission is observed, suggesting that very little particle precipitation occurs away from the polar regions
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