Scale analysis based on coarse-graining has been proposed recently as an alternative to Fourier analysis. It requires interpolation to a regular mesh for data from unstructured-mesh models. We propose an alternative coarse-graining method which relies on implicit filters using powers of discrete Laplacians. This method can work on arbitrary (structured or unstructured) meshes and is applicable to the direct output of unstructured-mesh models. Illustrations and details are provided for discrete fields placed at vertices of triangular meshes. The placement on triangles is also briefly discussed.

The collection of high-resolution data is helping researchers better understand form, process, and change in river systems and, especially, stream restoration projects. In the last 10 years it has become apparent that there is no “one-size-fits-all” approach to collecting high-resolution data for fluvial studies. The approach we demonstrate here is a self-contained pole aerial photography (PAP) system capable of collecting data for directly georeferenced structure from motion photogrammetry. PAP can produce higher-spatial resolution data than remotely piloted aerial system collected data and is one option where RPAS are restricted, like in parks and protected places. Another advantage of PAP is that it makes 3D data collection possible in parts of rivers, like under riparian canopies, that can elude capture with RPAS methods. Direct georeferencing removes the necessity for ground control points, which can greatly decrease the amount of time needed for a survey. The system that we developed combines a low-cost, dual-frequency GPS receiver capable of Real-time and Post-Processed Kinematic surveying with an off-the-shelf digital SLR camera, an inertial measurement unit, and 3D printed mounts and housings. The open-source control/survey software runs on an inexpensive Raspberry Pi computer with a 7-inch (18 cm) touch screen display. We highlight the accuracy of the system along with the high spatial resolution 3D data, ortho imagery, as well as other data that can be derived from these datasets such as sediment size measurements.

Mantle viscosity controls a variety of geodynamic processes, e.g. Glacial Isostatic Adjustment (GIA). Constraining GIA using better viscosity estimates would improve our estimates of recent ice mass loss from the Greenland and Antarctic ice sheets and the associated sea level rise. However, mantle viscosity is poorly constrained as it can rarely be measured directly, making geophysical observations that could place constraints on viscosity more essential. Empirically, viscosity is mainly controlled by temperature, water content of nominally anhydrous minerals, partial melt, grain size and stress. Of these, temperature, water content, and the presence of partial melt can be inferred from seismic and magnetotelluric (MT) measurements, which are important tools in imaging the subsurface of the Earth. In this study, we develop a method to estimate mantle viscosity in which we: (1) constrain temperature from MT, seismic, and surface heat flow observations; (2) constrain compositional structure (i.e., water content and partial melt) from MT and seismic data coupled with experimental mineral physics data; and finally, (3) convert the calculated thermal and compositional structures into a viscosity structure. In each step, we assess and quantify the involved uncertainties. In addition, we introduce a useful parameter – the viscosity ratio (a ratio between viscosities of a target region and a nearby reference region at the same stress and grain size), and quantify its amplitude and uncertainty for a range of temperatures and water contents. We find that the uncertainty in this ratio is relatively small when computed from both seismic and MT observations, compared to either constraint applied alone. We also explore how viscosity ratio uncertainties vary with grain size and stress. Information about grain size can potentially be obtained from seismic attenuation or tectonic history. Overall, we find that both seismic and MT observations can considerably improve estimates of mantle viscosity, and place useful constraints on its lateral variations in the upper mantle. Geophysically-derived mantle viscosity models can be calibrated in areas like Scandinavia, which has well-constrained GIA models, and applied to polar regions where the GIA response is poorly known.

The thermal regime of rivers plays a key role in aquatic ecosystem health. In the Willamette River, OR, main channel temperatures can be too warm for cold water fishes, causing fish to concentrate in secondary channel features including side channels, ponds, and alcoves. However, temperature regimes vary among and within features. Improved understanding of physical processes controlling thermal regimes in gravel-bed rivers is needed for targeted conservation action. This study characterized thermal regimes on the Willamette through field observations of temperature continuously measured at one side channel, eight alcoves, and six beaver ponds over a two month period. Insight into these measurements was provided by two dimensionless quantities. The Richardson number, characterizing stratification, was calculated with temperature and flow data. Values showed two well-mixed sites and 13 stratified sites. Stratification allowed calculation of the hyporheic-insolation number, characterizing the ratio of cooling flux from hyporheic discharge to heat transfer from incoming solar radiation. As calculated hyporheic-insolation numbers for sites increased, measured temperatures at sites decreased, showing a bin-averaged logarithmic fit R2=0.97. Results further indicate secondary channel features that provide cold water habitat are characterized by stratification and cool hyporheic discharge. Stratification is a necessary yet insufficient condition for cold water to provide habitat for aquatic biota because cold areas may still be anoxic, as suggested by dissolved oxygen point measurements. The hyporheic-insolation number has the ability to predict and thereby classify the thermal regimes of secondary channel features based on minimal field measurements and could guide floodplain restoration efforts.

The Patagonian slab window has been proposed to enhance the solid Earth response to ice mass load changes in the overlying Northern and Southern Patagonian Icefields (NPI and SPI, respectively). Here we present the first regional seismic velocity model covering the entire north-south extent of the slab window. A slow velocity anomaly in the uppermost mantle indicates warm mantle temperature, low viscosity, and possibly partial melt. Low velocities just below the Moho suggest that the lithospheric mantle has been thermally eroded over the youngest part of the slab window. The slowest part of the anomaly is north of 49°S, implying that the NPI and the northern SPI overlie lower viscosity mantle than the southern SPI. This comprehensive seismic mapping of the slab window provides key evidence supporting the previously hypothesized connection between post-Little Ice Age anthropogenic ice mass loss and rapid geodetically observed glacial isostatic uplift (≥ 4 cm/yr).

As already presented at previous conferences, we have developed an innovative technique for ocean wave observations from space: A dedicated reprocessing of spotlight-mode synthetic aperture radar (SAR) data enables us to produce a series of images covering a total time interval of a few seconds, in which moving wave patterns become visible. In most cases, the duration and quality of the image series is sufficient for computing a wavenumber-frequency spectrum and applying a dispersion relation filter to separate signatures of actual ocean waves from contributions of other physical phenomena and noise. Then the extracted wave signatures can be inverted into surface slope and displacement fields (in the space-time domain) and / or spectra (in the wavenumber-frequency domain) by applying relatively simple linear modulation transfer functions. Altogether this process is much more straightforward than traditional wave retrieval techniques for SAR images, and we think it produces more accurate results, although a full quantitative validation is still to be completed. This presentation at Ocean Sciences 2020 will not focus on the waves themselves, but on secondary information that can be retrieved from the moving wave patterns: Since the dispersion relation of ocean waves depends on water depth and surface current, these two parameters need to be tuned to fit the shape of the “dispersion shell” to the observed spectral energy distribution in each subwindow of a SAR image for which the wave field is analyzed. Accordingly, depth and surface current are obtained as additional outputs of the dispersion relation filter. This methodology is well established in the marine radar community, but has not been applied to satellite data before, where it presents a range of new opportunities as well as specific challenges. We will discuss the potential of the proposed method for practical applications and show first examples of retrieved nearshore wave, depth, and surface current fields.

The observed sea level (SL) around the Japanese coast shows a peculiar multidecadal variation with the peak in the 1950s followed by the gradual fall until the 1970s and the rebound continuing to the present, making the recent SL rise less remarkable in the historical record. An ensemble mean of the historical simulations conducted for the Coupled Model Intercomparison Project phase 6 (CMIP6) using the Meteorological Research Institute Earth System Model version 2.0 (MRI-ESM2.0) reproduces this variability well, implying that this was a forced one. The MRI-ESM2.0 simulations for the Detection and Attribution Model Intercomparison Project suggest that the increase in anthropogenic aerosols caused the SL fall from the 1950s to the 1970s and the increase in greenhouse gases caused the SL rise after that. Additional sensitivity runs indicate that the surface heat loss in the North Pacific due to anthropogenic aerosols plays a dominant role in the SL fall.

A document by PJ Tuckman. Click on the document to view its contents.

Analytical long-profile models of fluvial incision are fundamental in geomorphology, however, analogous models are missing for glaciers, despite the fact that glaciers are an important and widespread agent of physical erosion. We introduce a new analytical solution for coupled glacial-fluvial networks under steady-state climate and uplift. We then integrate this solution into a critical wedge orogen theory to explore the effect of glaciation on the balance between climate, erosion and orogen geometry. We find that the relief is closely tied to the equilibrium line altitude (ELA) and that the geometry and average uplift rate can respond significantly more sensitively to changes in climate than critical wedge orogens dominated by fluvial erosion. Using this observation, we suggest that the global lower ELA during glacial maximums over the last few millions years could trigger narrowing of critical orogens, with an associated increase in uplift rates within the active orogen core.

This study aims to create observation-based cloud radiative kernel (CRK) datasets and evaluate them by direct comparison of CRK and the CRK-derived cloud feedback datasets. Based on the International Satellite Cloud Climatology Project (ISCCP) H datasets, we calculate CRKs (called ISCCP-FH or FH CRKs) as 2D joint function/histogram of cloud optical depth and cloud top pressure for shortwave, longwave, and their sum, Net, at the top of atmosphere (TOA), as well as, for the first time, at the surface (SFC) and in the atmosphere (ATM). All the FH CRKs are physically plausible. The direct comparison shows that FH agrees reasonably well with three other TOA CRK datasets. With cloud fraction change (CFC) datasets of the same histogram for doubled-CO2 simulation from 10 CFMIP1 models, we derive all the TOA, SFC and ATM cloud feedback using the FH CRKs. Our TOA cloud feedback is highly similar to the previous counterparts. Based on the comparison for the 4 CRK datasets and the 10 CFC datasets, we estimate the uncertainty budget for the CRK-derived cloud feedback, which shows that the CFC-associated uncertainty contributes > 98.5% of the total cloud feedback uncertainty while CRK’s is very small. Our preliminary evaluation also shows that some near-zero/small cloud feedback in the TOA-alone feedback indeed results from the compensation of sizable cloud feedback of the SFC and ATM feedback, demonstrating how the SFC- and ATM-CRK derived cloud feedback can be valuable in revealing some significant surface and atmospheric cloud feedback whose sum appears insignificant in TOA-alone feedback.

A large part of hydrated oceanic lithosphere consists of serpentinites exposed in ophiolites, which constitute reactive chemical and thermal systems and potentially represent an effective sink for CO2. Understanding carbonation mechanisms is almost exclusively based on studies of outcrops, which can limit the interpretation of fossil hydrothermal systems. We present stable and radiogenic carbon data that provide insights into the isotopic trends and fluid evolution of peridotite carbonation in ICDP Oman Drilling Project drill holes BA1B (400 m deep) and BA3A (300 m deep). Geochemical investigations of the carbonates in serpentinites indicate formation in the last 50 kyr, implying a distinctly different phase of alteration than the initial oceanic hydration and serpentinization of the Samail Ophiolite. The oldest carbonates (~31 to over 50 kyr) are localized calcite, dolomite, and aragonite veins, which formed between 26 to 43 degrees Celcius and are related to focused fluid flow. Subsequent pervasive small amounts of dispersed carbonate precipitated in the last 1000 yr. Macroscopic brecciation and veining of the peridotite indicate that carbonation is influenced by tectonic features allowing infiltration of fluids over extended periods of time and at different structural levels such as along fracture planes and micro-fractures and grain boundaries, causing large-scale hydration of the ophiolite. The formation of dispersed carbonate is related to percolating fluids with δ18O lower than modern ground- and meteoric water. We also show that radiocarbon investigations are an essential tool to interpret the carbonation history and that stable oxygen and carbon isotopes alone can result in ambiguous interpretations.

The increased deforestation and urbanization of Earth’s surface changes how the soil system interacts with plants and understanding this relationship is vital in this time of climate change. Yet, how soil affects carbon and water use efficiency in plants is poorly understood. Studies show strong relationships between soil nutrient and vegetation carbon use efficiency (CUE) and water use efficiency (WUE) for different ecosystems; however, studies rarely have examined the combined effects of soil characteristics and nutrients on CUE and WUE. This study use both soil profile and satellite data to explore the role soil properties play in regulating water and carbon use by plants. Site and satellite multispectral and hyperspectral data are collected from 30 Kentucky terrestrial ecosystem sites and used to investigate the relationship between spectral reflectance and physical and chemical properties of soil. Results show strong relationship between CUE and phosphorus, soil organic carbon, and iron in the C-horizon for forests. On the contrary, a negative relationship was observed between CUE and SOC in the A-horizon for herbaceous biomes. Also, results show a strong relationship between δ13C and CUE for the forest sites. These types of data are timely and critical for accurate predictions of how terrestrial ecosystems will respond to climate change.

The NASA Goddard Earth Observing System (GEOS) Composition Forecast (GEOS-CF) provides recent estimates and five-day forecasts of atmospheric composition to the public in near-real time. To do this, the GEOS Earth system model is coupled with the GEOS-Chem tropospheric-stratospheric unified chemistry extension (UCX) to represent composition from the surface to the top of the GEOS atmosphere (0.01 hPa). The GEOS-CF system is described, including updates made to the GEOS-Chem UCX mechanism within GEOS-CF for improved representation of stratospheric chemistry. Comparisons are made against balloon, lidar and satellite observations for stratospheric composition, including measurements of ozone (O3) and important nitrogen and chlorine species related to stratospheric O3 recovery. The GEOS-CF nudges the stratospheric O3 towards the GEOS Forward Processing (GEOS FP) assimilated O3 product; as a result the stratospheric O3 in the GEOS-CF historical estimate agrees well with observations. During abnormal dynamical and chemical environments such as the 2020 polar vortexes, the GEOS-CF O3 forecasts are more realistic than GEOS FP O3 forecasts because of the inclusion of the complex GEOS-Chem UCX chemistry. Overall, the spatial pattern of the GEOS-CF simulated concentrations of stratospheric composition agrees well with satellite observations. However, there are notable biases – such as low NOx and HNO3 in the polar regions and generally low HCl throughout the stratosphere – and future improvements to the chemistry mechanism and emissions are discussed. GEOS-CF is a new tool for the research community and instrument teams observing trace gases in the stratosphere and troposphere, providing near-real-time three-dimensional gridded information on atmospheric composition.

In the previous papers in an elegant way we presented the unification of the fundamental interactions. We calculated the unity formulas that connect the coupling constants of the fundamental forces. Also the expression that connects the gravitational fine-structure constant with the four coupling constants. Perhaps the gravitational fine-structure constant is the coupling constant for the fifth force. Also we presented the unification of atomic physics and cosmology. We find the formulas for the cosmological constant and we propose a possible solution for the cosmological parameters. We present the law of the gravitational fine-structure constant followed by ratios of maximum and minimum theoretical values for natural quantities. We will prove the shape of the Universe is Poincaré dodecahedral space. From the dimensionless unification of the fundamental interactions will propose a possible solution for the density parameter of baryonic matter,dark matter and dark energy. The sum of the contributions to the total density parameter at the current time is Ω0=1,0139. It is surprising that Plato used a dodecahedron as the quintessence to describe the cosmos.

The Tibetan Plateau was formed by intense Cenozoic shortening (up to 1100 km) of a composite “proto-Tibet”, itself the product of a long Paleozoic and Mesozoic history of accretion of Gondwana-derived continental fragments and volcanic arcs against the Asian continental margin. The difficult access and the scarcity of outcrops have long limited the possibilities of studying these Mesozoic suture zones in the heart of the Plateau. In this work, we present new U-Pb and 40Ar/39Ar ages from the highly deformed units of the Yushu mélange, along the Jinsha Suture in the northeastern Qiangtang terrane. Early Triassic (c. 253 Ma) to Middle Jurassic ages (c. 165 Ma) complement the existing dataset and help to refine the chronology of the Paleo-Tethyan oceanic subductions which have structured the northeastern part of the Qiangtang terrane. The Yushu mélange records at least three successive tectono-magmatic events. The opening of a back-arc basin during the northward Paleo-Tethyan subduction along the Longmu Co-Shuanghu Suture during Early to Middle Triassic; then its closure during the southward subduction of the Songpan-Ganze Ocean along the Jinsha Suture in Late Triassic. Finally, a shortening phase related to the continental collision of the Songpan-Ganze and Qiangtang blocks from Late Triassic to Early-Middle Jurassic. No evidence for any high- or mid-temperature Cenozoic reactivation of the Jinsha suture in our study area is recorded.

Superparameterized (SP) global climate models have been shown to better simulate—as compared to conventional models—various features of precipitation, including diurnal timing as well as extreme events. While various studies have looked at the effect of differing microphysics parameterizations on precipitation within limited-area cloud-resolving models, we examine here the effect on continental-US extremes in a global SP model. We vary the number of predicted moments for hydrometeor distributions, the character of the rimed ice species, and the representation of raindrop self-collection and breakup. Using a likelihood ratio test and accounting for the effects of multiple-hypothesis testing, we find that there are some regional differences, both in the current climate and in a warmer climate with uniformly increased sea-surface temperatures. These differences are most statistically significant and widespread when the number of moments is changed. To determine whether these results are due to (fast) local effects of the different microphysics or the (slower) ensuing feedback on the large-scale atmospheric circulation, we run a series of short, 5-day simulations initialized from reanalysis data. We find that the differences largely disappear in these runs and therefore infer that the different parameterizations impact precipitation extremes indirectly via the large-scale circulation. Finally, we compare the present-day results with hourly rain-gauge data and find that, for the model configuration and resolution used, SP underestimates extremes relative to observations regardless of which microphysics scheme is used.

In Gale crater on Mars, the rover Curiosity has discovered evidence of fluid mobilization of the redox-sensitive element manganese. We present results for Mn from Curiosity’s Alpha Particle X-ray Spectrometer (APXS), which show that the average MnO concentration in mudstone-dominated sedimentary units (0.22 wt%) is about one-half of the concentration in the average Mars crust (0.44 wt%). Geochemical trends indicate that Mn in the sedimentary bedrock, most of which has a basaltic provenance, was leached by chemical alteration and dissolution. In >350 vertical meters of mudstone-dominated strata, the apparent leaching of Mn and retention of Fe in Fe-O-H phase(s) resulted in the fractionation of Fe and Mn, indicating relatively moderate Eh-pH fluid conditions that were not highly alkaline, reducing, or oxidizing. Exceptions are fracture-associated, silica-rich haloes where both Mn and Fe were leached by low pH fluids. The rover also discovered Mn-rich veins, nodules, and patchy, dark coatings on rock surfaces, which are variably associated with enrichments in Fe, P, Cl, and/or Zn. These Mn-rich features represent ~1% of the 1,029 APXS measurements acquired over ~25 km of rover traverse. A thermochemical model shows that dissolved Mn2+ could have been concentrated via evaporation, sublimation, and/or freezing. Manganese was then likely precipitated in localized features when > 99.99% of the Mn2+-bearing water was removed from the system. These findings indicate that Mn was mobile in Gale crater and therefore bioavailable as a potential energy source for life.

A document by yun jiang. Click on the document to view its contents.