Hydrological modeling of wetlands is important for reliable estimation of biogeochemical processes in soils subject to periodically inundating conditions. The present study has developed a wetland module in the Richards-equation-based SWAT model to fully couple the surface water storage and soil water dynamics. The wetland module was tested using observed daily water level data from four wetlands (including restored and natural wetlands with and without impermeable soil layers) in the Choptank River Watershed, Maryland, USA. After the wetland module was calibrated, simulated daily water level and observed data were compared and evaluated using three statistics, i.e., percent bias (Pbias), coefficient of determination (R2), and Nash-Sutcliffe coefficient (NS) from 2016 to 2017. The results showed that, in general, the wetland module regenerated hydroperiods for both restored and natural wetlands with and without impermeable soil layers; specifically, the module was able to accurately model saturation conditions for different soil layers corresponding to wet and dry periods in plant growing seasons; the wetland module had the tendency to generate better results for natural wetlands because restored wetlands tended to have mixed plant types which caused difficulty for accurate estimation of evapotranspiration; the ability to accurately describe inundation conditions for wetlands is important for biogeochemical modeling so that the newly developed wetland module has a great potential in enhancing simulation of biogeochemical cycles not only at the site scale but also at the watershed scale.

In the field geophysical instruments, various seismic sensors (an accelerometer, a velocimeter) and auxiliary equipment in the form of recorders (loggers) have been designed, which provide wireless information transfer to the data collecting and processing center. On the basis of these, instrumental earthquake observation systems have been developed to ensure the integrated security of critical facilities. These systems can be transformed to control global seismic monitoring of the territories, dams, also facilities of critical importance such as nuclear power plants, bridges, tunnels and technological pipelines for chemical and oil-processing plants. The report presents the technical characteristics of the above mentioned instruments and the possibilities of their wide application in different countries. Additionally, monitoring of seismicity of Armenian regions is implemented for the earthquake research.

The high sensitivity of the Visible Infrared Imaging Radiometer (VIIRS) Day Night Band (DNB) high gain stage (HGS) cannot directly use on-board calibration sources such as solar diffusers, so other calibration approaches are needed. A fully automated, NIST-traceable active point source called the Accurate Active Light Source (AALS) based on a 1-meter diameter integrating sphere illuminated with High Pressure Sodium (HPS) lamps has been developed to calibrate the VIIRS DNB HGS mode. This paper provides the theory and operation of the AALS. The AALS is housed in an environmentally controlled, moveable, enclosed trailer that protects the sphere and is being deployed in South Dakota during the summer and Mississippi during the winter. AALS Lambertian source radiance is measured by a NIST-traceable spectroradiometer. MODTRAN-based top of atmosphere (TOA) radiance is calculated using nighttime aerosol estimates and point source radiative transfer techniques that account for the VIIRS finite Point Spread Function (PSF). This new active point source complements current vicarious calibration techniques, which are based on lunar illumination of extended sources (clouds, playas, etc.), and helps improve our understanding of the point source radiative transfer needed to develop nighttime artificial light source applications. An uncertainty budget for TOA radiance indicates that accuracy under clear, moonless conditions should be comparable to daytime vicarious calibration methods. This paper shows that the major uncertainty is the ground-to-space atmospheric transmission and discusses approaches to reduce this error. Initial assessment of the VIIRS DNB HGS on the Suomi-NPP and NOAA-20 satellites are presented.

Ultrasound Computer Tomography (USCT) is an emerging technique for breast cancer screening. Ultrasonic waves are propagated through the tissue and recorded by a set of transducers that are surrounding the breast. The experiment collects transmission and reflection data, which are used to obtain quantitative images of acoustic properties of the tissue (see Figure). This information is useful to characterize the breast tissue, and improves the specificity of standard imaging modalities. However, providing a diagnostic tool with high accuracy and clinically affordable time-to-solution (goal: ~15 min/patient) still remains a challenge. The goal of this work is to show that, despite the vast scale differences, experiments in seismology and USCT share many similarities. In both fields, the relative wave speed variations are comparable and the number of propagated wavelengths in the domain has the same order of magnitude. Because the wave equation is scale invariant, the cross-fertilization between both fields will benefit imaging methods on all scales. In this study, we present methods from seismic tomography that we have recently introduced to USCT: 1) We employ a linearized finite-frequency traveltime tomography approach for speed-of-sound reconstruction. Using the cross-correlation traveltime misfit functional, we compute analytically the sensitivity kernels using adjoint techniques. Our method can operate almost in real time while still including finite-frequency effects. It also can retrieve useful 3D information from 2D acquisition systems. 2) Similar to exploration geophysics, both speed-of-sound and reflectivity images are important for the interpretation. Here, we suggest a framework that combines full-waveform inversion for speed-of-sound and reverse time migration for reflectivity. 3) We apply the Sequential Optimal Experimental Design (SOED) method to optimize the position and number of transducers, in terms of accuracy and cost, to image both reflection and transmission information. Using the Bayesian approach, we define the quality of a design as the average of the posterior variances of the parameters. SOED provides cost-benefit curves that quantifies the information gain versus the computational cost. These are useful to control the trade-off between accuracy and practicality.

Severe forest and peat fires in Indonesia have occurred more frequently in recent years. These fires have been associated with various types of ecosystems and land uses, ranging from the simplest to the most complex ones. However, recent fire control efforts in the country have primarily focused on fire suppression efforts instead of preventive measures. Fire prevention efforts are mostly statements of empty jargon rather than specific actions or policies. Fire suppression activities have been greatly preferred but have proceeded without properly accounting for whether the fires are on mineral soils or occurring within peat soils. Efforts to extinguish fires should be based upon their typology to be effective, especially for peat fires that having the distinct behavior of smoldering within the peat soils. However, field observations have shown that generalized approaches for extinguishing fire are undertaken on bot mineral soils where flaming surface fires predominate and peat soils where smoldering ground fires are common. Peat fires cannot be extinguished using the same suppression measures used for flaming surface fires and will, therefore, not achieve effective results without consideration of their unique burning typology. The severe peat fires in 2015 should be taken into account as a lesson learned and impetus for better peat fire control and prevention in the future. Keywords: Peat fires, fire typology, fire control, fire prevention

With temperatures rising in Arctic regions at double the global average, decomposition rates and subsequent greenhouse gas release into the atmosphere are expected to rise, potentially shifting these regions from carbon sinks to carbon sources. General circulation models predict the relationship between respiration and temperature using exponential functions, showing a temperature-independent rate of increase to decomposition rates with temperature. However, enzymes catalyzing carbon depolymerization reactions have demonstrated departures from this predicted increase between 10 and 15 °C. Organic tundra soils were incubated across this range (4 to 20 °C, 4 °C increments) and harvested consecutively after carbon losses equivalent to those after 2, 4, 8, and 12 days at 20 °C. During each harvest, β-glucosidase (BG) and β-xylosidase (BX) activities were measured at both the incubation temperature and at 20 °C to determine temperature limitations to enzyme activity and production. While enzyme activities in soils incubated at different temperatures diverged significantly when measured at different temperatures, these differences were overcome when measured at 20 °C, suggesting enzyme activities are more limited than enzyme production. Two exceptions to this trend were the first harvest of the 4 and 8 °C incubations, which had significantly higher BG and BX activities when assayed at 20 °C than soils incubated at higher temperatures, indicating larger enzyme pool sizes in soils incubated at lower temperatures. For BG activities, increased enzyme pool size offset low temperature limitations to enzyme activity, resulting in no difference in measured rates when the 4 and 8 °C soils were compared with the 12 and 16 °C soils, respectively. However, in subsequent harvests, BG and BX activities measured at 20 °C declined and activities at 4 and 8 °C were significantly lower than in assays at 12, 16, and 20 °C. Declining activities of these enzymes in the 4 and 8 °C incubations may indicate limited substrate accessibility or nutrient availability at lower temperatures due to changes in the relative rates of other decomposition reactions with temperature. Improving our understanding of the multifaceted impacts of temperature on decomposition reactions will be important to better model and predict future carbon release.

Understanding and communicating the impact of uncertainty on scientific understanding is a critical unmet need in Earth Science. Challenging as uncertainty determination is for “low level” data, the impact of further processing must be understood, particularly when integrating diverse data types. For example, a fundamental source of diversity is data’s spatiotemporal distribution, for which Point, Grid, and Swath are the most important overarching geographical types. To bring different kinds of data together or bring observational data and model simulations together, observation and simulation values must be “regridded” onto the same grid, i.e. onto a comparable spatiotemporal representation. At the finest level, this requires a detailed understanding of instrumental fields of view and sensitivities. But regridding itself affects uncertainty, especially in situations where significant or irregular interpolation or even extrapolation are required. Furthermore, care must be taken combining diverse data lest the integrated product inherit the worst uncertainty characteristics of each. We have been developing capacities for indexing, regridding, and integrating observation and model simulation that scale to the size and diversity of Earth Science data. In this presentation, we review the fundamental problems associated with combining big, diverse Earth Science data for integrative analysis and how to quantitatively assess and propagate the uncertainties introduced. In particular, uncertainties associated with regridding diverse data for various popular grids and regridding schemes will be assessed.

In the paper summarized by this presentation we trace how maps aided the conceptualization and ensuing debate over one of the first inherently spatial and multiscale environmental issues, acid rain. Through interviews with early acid rain ecologists and a critical cartographic analysis of printed maps, we show that mapping was central for constructing this environmental issue. Rather than static representations of a scientific reality, acid rain maps were interconnected and relational processes that operated within political and economic discourses. Accordingly, we suggest that increased critical engagement and participation with the process of mapping can productively aid dialog on many issues, including other current multiscale environmental issues, such as climate change.

The Space Physics Data Facility (SPDF) has developed and/or leveraged standardized self-describing data formats, metadata for datasets and parameters, time conventions, and dataset and filenaming conventions that enable effective data analysis and browsing using generic easy-to-use software and web services. Software and services include SPDF’s CDAWeb , and external tools such as Autoplot and SPEDAS IDL library. Standards and conventions include: datasets and filenaming and , the CDF scientific data format (including its new Python library ), the ISTP/IACG/SPDF Guidelines for global and variable attributes , time variable types , and the SKTeditor metadata creation tool . The SPASE standards for describing datasets for easy searching are crucial to the Heliophysics Data Portal .

Continental shelves are important land-ocean interfaces where natural and anthropogenic processes, as well as sediment geochemistry regulate the sequestration of organic matter (OM) in the sediment. In the Northern Gulf of Mexico, along the Louisiana shelf, the Mississippi River discharge asserts strong seasonal controls over primary production and sedimentary reserves of minerals. Recent studies have shown the importance of mineral-organic matter interactions in the sedimentary OM preservation, both of which are abundant in this region. Thus, the major objective of this work is to understand the spatial and temporal variability of the sediment organic carbon (OC) directly bound to the reactive iron (rFe) mineral phases such as goethite, ferrihydrite, lepidocrocite and hematite. Sediment samples were collected from five sites along the river plume during periods of low (August/September 2016) and high (May 2017) river discharge. Average rFe content in the top 20 cm of sediment was significantly higher at all sites in May (6.9 ±1.5 mg gdw-1) compared to August (4.3± 0.6 mg gdw-1), while particulate OC content in these sediments was higher in August (11.9 ± 3.7 mg gdw-1) compared to May (7.4± 4.7 mg gdw-1). However, the bulk OC bound to rFe in these sediments did not vary significantly between the two seasons and ranged between 2.3 - 3.4 mg gdw-1. Molar OC: Fe ratios in the OC associated with rFe ranged between 0.9-6.2, with higher ratios in the deeper sediment sections (5-20 cm) than at the top (0-5 cm). Our results indicate that 27- 32% of the total OC in sediment is associated with rFe phase and preserved in these recent shelf sediments. A combination of X-ray diffractometry and Fe-K Edge X-ray absorption near edge structure spectroscopy analyses were carried out to identify the mineralogical composition of rFe bound to the organic carbon in the sediments. Preliminary findings indicate that most of the iron is found as non-reactive iron in clay mineral smectite, but the dominant form of rFe associated with OC is goethite.

ICESat-2 carries NASA’s next-generation laser altimeter, ATLAS, (Advanced Topographic Laser Altimeter System), designed to measure changes in ice sheet height, sea ice freeboard, and vegetation canopy height. ATLAS contains a photon-counting lidar which transmits green (532-nm) pulses at 10kHz. Each pulse is split into 3 pairs of beams (one strong and one weak). Approximately 1014photons per pulse travel from ATLAS through the atmosphere to reflect off the Earth’s surface. Some return back into the ATLAS telescope where they are recorded. Photons from sunlight and instrument noise at the same wavelength are also recorded. The flight software time tags all photons within a 500m to 6 km range window and generates histograms. Using the histograms, it selects a telemetry window which varies from 20m over flat surfaces to hundreds of meters over rougher terrain. ATL03 contains the time, height (relative to the WGS-84 ellipsoid), latitude and longitude of every photon within the telemetry window. The basic challenge is to determine which of these photons were reflected off the surface. We have developed an algorithm that identifies these signal photons and assigns a confidence level (low, medium, or high) to each signal photon based on the signal to noise ratio. We present an overview of the signal identification algorithm and show the results on actual ICESat-2 data over ice sheet, sea ice, vegetated, and water surfaces. Higher level ATLAS products work with aggregations of the photons in order to determine the ellipsoidal height of the Earth, canopy height and structure, and other quantities of geophysical interest.

A number of studies in recent years have reported about the lunar tidal enhancements in the equatorial electrojet (EEJ) from ground- and space-based magnetometer measurements during stratospheric sudden warming (SSW) events. In this study, we make use of the ground magnetometer recordings at Huancayo observatory in Peru for the years 1978 – 2013 to derive a relationship between the lunar tidal enhancements in the EEJ and tropospheric eddy heat fluxes at 100 hPa during the SSW events. Tropospheric eddy heat fluxes are used to quantify the amount of wave activity entering the stratosphere. Anomalously large upward wave activity is known to precede the polar vortex breakdown during SSWs. We make use of the superposed epoch analysis method to determine the temporal relations between lunar tidal enhancements and eddy heat flux anomalies during SSWs, in order to demonstrate the causal relationship between these two phenomena. We also compare the lunar tidal enhancements and eddy heat flux anomalies for vortex split and for vortex displaced SSWs. It is found that larger lunar tidal enhancements are recorded for vortex split events, as compared to vortex displaced events. This confirms earlier observation; larger heat flux anomalies are recorded during vortex split SSW events than the heat flux anomalies during vortex displaced SSW events. Further, the temporal relations of lunar tidal enhancements in the EEJ have been compared separately for both the QBO phases and with the phases of the moon with respect to the central epoch of SSWs by means of the superposed epoch analysis approach. The EEJ lunar tidal enhancements in the east phase of QBO are found to be larger than the lunar tidal enhancements in the west phase of QBO. The phase of moon relative to the central SSW epoch also affects the lunar tidal enhancement in the EEJ. It is found that the lunar tidal enhancements are significantly larger when the day of new or full moon lies near the central SSW epoch, as compared to cases when new or full moon occur further away from the central SSW epoch.

Arctic warming is outpacing the global rate of climate change, with up to 11 degrees C of warming projected by the year 2100 if greenhouse gas emissions follow their current trajectories. Increasing temperatures are expected to result in permafrost thaw, and the combined effects of precipitation changes, soil warming, and active layer deepening are expected to result in net soil drying. While there is widespread agreement that increasing temperatures and active layer depth will release carbon from soils, the effect on vegetative C cycling is less certain. In 2017, we conducted an experiment to examine the effects of soil drying and active layer deepening on primary productivity in Eriophorum vaginatum, a dominant circumpolar Arctic sedge, and the extent to which those effects vary across ecotypes. We harvested E. vaginatum tussocks from three sites along a latitudinal gradient in the Alaskan Arctic, placed them in pots filled with peat soil, and assigned each to one of three drying treatments. In one treatment, the soils were kept saturated with water through the growing season. In the second treatment, rain was excluded in alternating two-week cycles. In the third treatment, rain was also excluded in alternating two-week cycles, and the soil column was approximately doubled in depth to allow deeper drainage. We measured soil moisture, leaf water potential, leaf area index (LAI), leaf-level phenology, and photosynthetic capacity (Amax) in each of the tussocks. We found that the southern ecotype was affected most severely by drying, with reductions in LAI, maximum leaf length, and Amax. We found that effects were greater with rain exclusion and soil column deepening than with rain exclusion alone. However, we found no difference in leaf water potential between populations or treatments, suggesting that E. vaginatum leaves function within a fairly narrow range of moisture conditions. These results demonstrate that changes in soil moisture may affect carbon storage in Arctic vegetation, but that the magnitude of the effect may vary depending on region and ecotype.

As a national strategic resource, trade activities of potassium resources（K） have changed its state of ownership. Futures and spot trading forms in the international market are mainly primary processed ore and deep-processed products. So, K trade can be replaced by the potassium salt trade. Its international trade will affect a country’s strategic resource management, and increase national resource security risks. Thence, it is necessary to study the evolution of international trade in K. This paper has constructed a weighted and directed complex network model of K trade using UN Comtrade 2000-2016 data and analyzed the scale and activity of international trade of K, trade relations, trade flow distribution and the importance of countries. By analyzing the international trade data of K in 224 countries, it is found that trade is active year by year and K is becoming more significant. From network density and diameter, resource allocation is more convenient. The network cluster is growing. It shows that some countries form trade groups. The correlation coefficient of degrees is less than 0, indicating that the trade relationship between small and major trade countries is enhancing. And, the reciprocal coefficient is between 0.1 and 0.35, showing that the trade order is poor. Moreover, it presents a state that the greater the country’s degree, the smaller the difference in trade flow distribution. So, resource flows in countries with more trade relations can promote a balanced distribution of K. Finally, from countries’ trade influence and hub status, Canada is a leading trade country, and the US, the Russian Federation, China and Brazil are trade-led countries. They are the main source of K flows. China, the Netherlands, the US, France and India are important hubs. So, countries should strengthen bilateral trade relations. So as to ensure the SD of international trade in K, major trading countries should focus on the exploit of K and improve the level of production and processing tech. Countries should also enhance their hub role to facilitate the flow of K. China, as a large country in agriculture and K demand, should increase self-sufficiency to reduce import dependence risks. Besides, attention should be paid to market changes in major trading countries and to reducing risks by adding the number of trade countries.

Immersion freezing is an important heterogeneous ice nucleation process in mixed-phase clouds. Many researches on immersion freezing focus on the parameterization using the classical nucleation theory. However, the ice nucleating abilities of the atmospheric aerosol particles are not well understood, and therefore cause difficulties of the parameterization of immersion freezing. In this study, we investigate the ice nucleating ability of Marigold pollen from the Beijing area by doing drop immersion freezing experiments in the laboratory. Marigold pollen are first mixed with pure water. A population of drops with a volume of 10 mL from the mixture are then put on a PE film in a chamber with a cooling rate of about 0.5 °C min-1. We find that the median freezing temperature of drops with pollen as ice nuclei is -17 °C. The contact angle parameterization of immersion freezing using the classical nucleation theory is also given in this study. We use the single-θ and the θ-pdf parameterization schemes to explain the data. The results show that the θ-pdf parameterization scheme is better for describing the ice nucleating behavior of the pollen in Beijing.

Water security hinges on water storage. Although the public and water resources planners habitually look to surface reservoirs for storage solutions, by far the largest ‘space’ to store water is underground. The very nature of freshwater distribution on Earth foreshadows future water storage solutions, as 97% of all circulating freshwater globally is in groundwater. Similarly, although 140 surface reservoirs in California can store 52 km3(42 MAF), in the Central Valley aquifer system there is room for another ~170 km3(~140 MAF) owing to past depletion. Despite the state’s Mediterranean climate in which nearly all of the precipitation occurs between November and March when demand is lowest, historically massive snow storage and spring-summer snow melt synchronized well with surface reservoir replenishment during April-July. This system built around snow storage as a means of mitigating winter flood threats and delaying runoff until the beginning of the peak demand season is clearly demonstrating significant vulnerabilities to climate change and drought. Climate warming has already produced decades of declining snowmelt runoff, making surface reservoir storage more difficult. Moreover, as demonstrated during the 2012-16 drought, in the face of droughts longer than a few years, the surface storage offers inadequate long-term water security. This fact, the fact that California during pre-development times of the last millennium experienced far longer droughts, and ongoing climate change clearly indicate the need for a different strategy that more fully leverages both surface and subsurface storage. Kocis and Dahlke (2017) show that increasing winter runoff during wet and normal years provide enough high-magnitude flows to support a strategy of diverting flood flows for groundwater storage. This “flood-MAR” (managed aquifer recharge) approach will require a massive change in winter water and land management that exploits recharge opportunities on irrigated farm lands and in areas with suitable soils and subsurface geology. A case study in the American-Cosumnes Rivers portion of the Central Valley shows how total system water storage can be increased dramatically through diversion of high-magnitude flows and reoperation of both the surface and subsurface reservoirs including economic incentives.

Surveying the seafloor with new technologies and techniques provides a new generation of higher-resolution imagery of both bathymetry and benthic habitat. Recent surveys using an Edgetech 4600 interferometric sonar have identified previously unknown patterns in these properties in the estuarine and nearshore areas in coastal Georgia, USA. As part of a multi-year mapping effort, four of the seven sounds in coastal Georgia have been mapped: Wassaw Sound, Ossabaw Sound, St. Catherine’s Sound and Sapelo Sound. Interferometry, sidescan sonar imagery and bottom sediment character have been combined to identify bathymetric patterns, diverse benthic habitats and to produce comprehensive habitat maps. Although the distribution of habitat types differs within each of these sites, all habitat types are common to all areas, and some general patterns emerge. Each site exhibits regions of mobile sediments, but of critical importance, also exhibits deep scours into semi-indurated materials that create vertical relief and hard substrates. Each project area can be divided into geomorphological features i.e., channels, deep depressions, vertical walls, ridges and flats. Bedforms are commonly visible, particularly in channels and depressions. Sediments are dominated by sand. These data, along with derivatives e.g., slope, rugosity and bathymetric position index, identify potentially important, complex habitat for sessile and mobile organisms. Scarps and ledges (up to 2 m high, up to 1000 m long) are distinctly recognizable in the sidescan imagery and slope analysis. This presentation will describe the procedures for working with shallow water interferometric sonar data and interpretations that can be reached using these tools.

The Piacenzian (Late Pliocene) represents a natural laboratory within which frequency and magnitude of environmental changes during a period of past global warmth can be analyzed, climate models can be tested, and results can be placed in a context to better prepare for future change. We focus on the North Atlantic and both generate new and incorporate existing faunal assemblage and alkenone data from DSDP Sites 552 and 606, ODP Sites 662, 981, 982, and 999, and IODP Sites 1307, 1308 and 1313. In addition, cores and outcrop material containing Piacenzian sediments from the Atlantic Coastal Plain of Virginia, USA, are included. These data allow us to characterize regional changes in temperature, salinity, upwelling, productivity, and diversity, associated with climate transitions, and make nuanced reconstructions of mid-Piacenzian conditions within a high-resolution temporal framework between ~3.40 and ~3.15 Ma, inclusive of Marine Isotope Stages M2 through KM5. Our results indicate the slope of the North Atlantic sea surface temperature gradient is a robust feature of the Late Pliocene and we confirm a temperature anomaly (Pliocene minus pre-industrial) little to no change at the equator to >6° C near 60° North, during Marine Isotope Stage (MIS) KM5c (3.21 Ma – 3.20 Ma). The M2-M1 transition is accompanied by warming, rapid sea-level rise, reorganization of planktonic foraminifer assemblages, decreases in productivity and increase in zooplankton diversity. Abundance changes in stenohaline taxa document repeated freshening of the Caribbean by low latitude Pacific water associated with brief re-openings of the Central American Seaway. The Gulf Stream – North Atlantic Drift migrated to a more northerly position during both the M2-M1 and KM6-KM5 transitions. Preliminary comparison of these results to climate simulations produced by the second phase of the Pliocene Model Inter-comparison Project (PlioMIP2) indicates model output and reconstructed environmental data are in closer agreement than previous data-model comparisons. We attribute this to a combination of improved Pliocene Research, Interpretation and Synoptic Mapping (PRISM4) boundary conditions, and the refined stratigraphic window used for verification, compared to PRISM3.