Assessing atmospheric predictability on Mars using numerical weather prediction and data assimilation

Introduction: Studies of the time series of surface measurements of wind, pressure and temperature at the two Viking landers by Barnes [1], [2] revealed that baroclinic transient travelling waves on Mars occur mostly during northern hemisphere autumn, winter and early spring, and typically take the form of highly coherent patterns with planetary wavenumbers 1-3 that can persist for intervals of up to 30-60 sols before changing erratically. Such behaviour is almost unknown on Earth, where individual baroclinic weather systems typically persist for no longer than 5-10 days and seldom remain coherent around entire latitude circles. This occurrence of planetary-scale coherent baroclinic wave-like weather systems on Mars led to suggestions [3] that Mars' atmospheric circulation operates in a quite different dynamical regime to that of the Earth, one that tends to favour regular, symmetrical baroclinic wave activity in a manner reminiscent of the regular wave regimes found in laboratory fluid dynamics experiments on sloping convection in a rotating, thermally-driven fluid annulus (e.g. [4], [5]). In its extreme form, this hypothetical comparison would suggest the possibility of a fully non-chaotic atmospheric circulation on Mars, though subsequent modelling work [6] indicated that perturbations due to the thermal tide would lead to chaotic transitions back and forth between different intransitive wave states. This form of (relatively low-dimensional) chaotic modeflipping appeared to be consistent with the Viking observations of Mars, suggesting nevertheless that the intrinsic predictability of Mars' mid-latitude meteorology was qualitatively and quantitatively quite different from that of the Earth

Potential vorticity, angular momentum and inertial instabilities in the Martian atmospheric circulation from assimilated analyses of MGS/TES

Data based on re-analyses of the MGS/TES observations have been used to map distributions of potential vorticity and axial absolute angular momentum per unit mass. The data, discussed in more details in [1] and [2] stretches over nearly three Martian years and cover a wide range of atmospheric conditions. The spatial distribution and variation in time of angular momentum and potential vorticity are closely related to the zonal-mean circulation. Maps of potential vorticity distributions have been used to establish regions and times favourable for inertial instabilities. A narrow region near the equator which extends throughout the atmosphere is shown to be able to sustain inertial instabilities at different times of the year. The presence of inertial instabilities is predicted from the necessary (but not sufficient) condition for the occurrence of regions of atmosphere with PV of opposite sign to that of the planetary vorticity (PVanomalies). These regions are characterized as being favorable to mixing on small scales, while at larger scales there may be potential links to Rossby wave breaking (Knox et. al. 2005][3]. Analyses of the data indicates a hemispheric asymmetry where the northern hemisphere is more favorable to inertial instabilities particularly during NH winter. Barnes et. al. (1996)[4] used a global Martian circulation model to find that, during dusty solstice conditions, the Martian tropical and mid-latitude atmospheric circulation approximates to an angular-momentum conserving Hadley circulation, and is responsible for creating regions near the equator of low potential vorticity. Using the assimilated data we re-examine these results for a wider range of atmospheric states, including the period of the 2001 planet-encircling dust storm

Data assimilation for Mars: an overview of results from the Mars Global Surveyor period, proposals for future plans and requirements for open access to assimilation output

Abstract not available. From the introduction: 'The Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor (MGS) has produced an extensive atmospheric data set, both during the initial aerobraking hiatus and later from the scientific mapping phase of the mission which lasted almost three complete Martian seasonal cycles. Thermal profiles for the atmosphere below about 40 km, and total dust and water ice opacities, have been retrieved from TES spectra (Conrath et al., 2000, Smith et al., 2000)...'

Climatology on Mars: interannual variability of mean fields

Not availabl

Data assimilation of three mars years of thermal emission spectrometer observations: Large-scale transient and stationary waves

Introduction: Large-scale traveling and stationary planetary waves are diagnosed from an analysis of profiles retrieved from the Thermal Emission Spectrometer (TES) [1] aboard the Mars Global Surveyor (MGS) spacecraft during its scientific mapping phase. The analysis was conducted by assimilating the TES temperature profile and total dust opacity retrievals [2] into a pseudo-spectral Mars general circulation model to produce a full, physically self consistent record of all atmospheric variables stored at an interval of two hours over the entire MGS mapping phase. The data cover a period of about three Mars years, corresponding to the interval 1999–2004 on Earth. These include the year which contained the 2001 global dust storm [3] and two years of more moderate dust activity, although large regional storms occurred during southern hemisphere summer in both years and there was considerable atmospheric variability between all three years [4]. We focus on the planetary wave activity, both traveling and stationary large-scale waves, in the assimilated record. Data assimilation is a particularly useful technique for the analysis of transient wave behaviour since it is capable of producing global, time-dependent atmospheric fields, which the assimilation scheme endeavours to make as consistent as possible with whatever observations are available. These atmospheric variables may be sampled from the model as often as desired, on a regular grid of points. If particular variables, or regions of the atmosphere, are not observed directly, the model will at least ensure that they are consistent with the laws of physics incorporated within its framework. A complex climatology of transient waves is revealed, modulated by the large-scale topography and surface thermal properties, the time of year and, crucially, the amount of dust suspended in the atmosphere. Some individual case studies show the temporal and spatial structures of the waves in the assimilation record, although the large data set has by no means been fully explored. Companion papers discuss the thermal atmospheric tides [5] and the processes associated with the initiation of dust storms [6] from the same assimilated analysis. Output from the same assimilation has also been used to identify potential deficiencies in the model, such as the lack of water ice clouds [7]

The ISSI international study team on the martian PBL – status report and plan

Dynamical processes in the Martian boundary layer provide the means of communication between surface ice deposits and the free atmosphere, and the means of lifting dust from the surface. The boundary layer is therefore one of the most important components of the Martian climate system. The Martian boundary layer differs from that of the Earth in that it is more strongly forced, it is deeper, and the relative importance of radiative and convective heat fluxes in the lower boundary layer can be quite different. In order to understand the Martian boundary layer, a combination of theoretical, modeling and observational studies are necessary. Interactions between theorists, modelers, and observational scientists are needed to make progress and to provide a basis for analysis of data expected from Phoenix, Mars Science Laboratory, ExoMars and other future landed missions (such as a surface network mission), or missions such as balloons or other aircraft operating in the neutral atmosphere. The prime goal of this project under the auspices of the International Space Science Institute (ISSI) is to review and assess the current knowledge and understanding of Martian planetary boundary layer and its interactions with the surface and free atmosphere. We aim to promote international communication and collaboration to enhance the rate of acquisition of knowledge and understanding. This will be achieved through an International Study Team and publication of overview papers and individual reports on recent advances in this area

Association between GNRHR, LHR and IGF1 polymorphisms and timing of puberty in male Angus cattle

<p>Abstract</p> <p>Background</p> <p>In bovines, there are significant differences within and among beef breeds in the time when bulls reach puberty. Although the timing of puberty is likely to be a multigenic trait, previous studies indicate that there may also be single genes that exert major effects on the timing of puberty within the general population. Despite its economic importance, there are not many SNPs or genetic markers associated with the age of puberty in male cattle. In the present work, we selected three candidate genes, <it>GNRHR</it>, <it>LHR </it>and <it>IGF1</it>, and associated their polymorphisms with the age of puberty in Angus male cattle.</p> <p>Results</p> <p>After weaning, 276 Angus males were measured every month for weight (W), scrotal circumference (SC), sperm concentration (C) and percentage of motility (M). A total of 4 SNPs, two within <it>GNRHR</it>, one in <it>LHR </it>and one in <it>IGF1 </it>were genotyped using the pyrosequencing technique. <it>IGF1-SnaBI SNP </it>was significant associated (P < 0.01) with age at SC 28 cm, but it were not associated with age at M 10% and C 50 million. Genotype <it>CC </it>exhibited an average age at SC 28 cm of 7 and 11 days higher than <it>CT </it>(p = 0.037) and <it>TT </it>(p = 0.012), respectively. This SNP explained 1.5% of the genetic variance of age of puberty at SC28. <it>LHR-I499L</it>, <it>GNRHR-SNP5 </it>and <it>GNRHR-SNP6 </it>were not associated with any of the measurements. However, <it>GNRHR </it>haplotypes showed a suggestive association with age at SC 28 cm.</p> <p>Conclusions</p> <p>The findings presented here could support the hypothesis that <it>IGF1 </it>is a regulator of the arrival to puberty in male calves and is involved in the events that precede and initiate puberty in bull calves. Given that most studies in cattle, as well as in other mammals, were done in female, the present results are the first evidence of markers associated with age at puberty in male cattle.</p

Refining genomewide association for growth and fat deposition traits in an F₂ pig population

The identification of genomic regions that affect additive genetic variation and contain genes involved in controlling growth and fat deposition has enormous impact in the farm animal industry (e.g., carcass merit and meat quality). Therefore, a genomewide association study was implemented in an F₂ pig population using a 60,000 SNP marker panel for traits related to growth and fat deposition. Estimated genomic EBV were linearly transformed to calculate SNP effects and to identify genomic positions possibly associated with the genetic variability of each trait. Genomic segments were then defined considering the markers included in a region 1 Mb up- and downstream from the SNP with the smallest -value and a false discovery rate < 0.05 for each trait. The significance for each 2-Mb segment was tested using the Bonferroni correction. Significant SNP were detected on SSC2, SSC3, SSC5, and SSC6, but 2-Mb segment significant effects were observed on SSC3 for weight at birth (wt_birth) and on SSC6 for 10th-rib backfat and last-rib backfat measured by ultrasound at different ages. Furthermore, a 6-Mb segment on SSC6 was also considered because the 2-Mb segments for 10 different fat deposition traits were overlapped. Although the segment effects for each trait remain significant, the proportion of additive variance explained by this larger segment was slightly smaller in some traits. In general, the results confirm the presence of genetic variability for wt_birth on SSC3 (18.0-20.2 Mb) and for fat deposition traits on SSC6 (133.8-136.0 Mb). Within these regions, fibrosin (FBRS) and myosin light chain, phosphorylatable, fast skeletal muscle (MYLPF) genes could be considered as candidates for the wt_birth signal on SSC3, and the SERPINE1 mRNAbinding protein 1 gene (SERBP1) may be a candidate for the fat deposition trait signals on SSC6.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari