bluuebunny/crossref_metadata_2025 huggingface dataset:
A probabilistic prediction of rogue waves
Authors: Gemmrich Johannes , Cicon Leah , Pouliot Benoit , Bernier Natacha
Published: February 2023

Rogue waves are individual ocean surface waves with a height greater than 2.2 times the significant wave height.  They can pose a danger to marine operations, onshore and offshore structures, and beachgoers, especially when encountered in high sea states. The prediction of bulk sea state parameters like significant wave height, period, direction, and swell components is satisfactorily addressed in current operational wave models. Individual wave heights cannot be predicted by those spectral models, and the prediction of rogue wave occurrence has to be in a probabilistic sense.Previous attempts on such a prediction are based on the Benjamin Feir Index (BFI), which reflects the nonlinear process of modulation instability as the dominant generation mechanism for rogue waves. However, there is increasing evidence that BFI has limited predictive power in the real ocean. Recent studies established the average crest-trough correlation as the strongest single variable to correlate with rogue wave probability.We demonstrate that crest-trough correlation can be forecast by an operational WAVEWATCHIII wave model with moderate accuracy. Using multi-year wave buoy observations from the northeast Pacific we establish the functional relation between crest-trough correlation and rogue wave occurrence rate, thus calibrating predicted crest-trough correlations into probabilistic rogue wave predictions. Combined with the predicted significant wave heights we can identify regions of enhanced rogue wave risk. Results from a case study of a large storm off Canada’s west coast are presented to evaluate the regional wave model at high seas, and to present the rogue wave probability forecast based on crest-trough correlation.
Expansion of the NASA Astrophysics Data System to Earth and Space Sciences
Authors: Accomazzi Alberto ,   ADS Team
Published: February 2023

The NASA Astrophysics Data System (ADS) is the primary Digital Library portal for Space Science Researchers. In addition to the scientific literature, the ADS has for a long time included in its database non-traditional scholarly resources such as research proposals, software packages, and high-level data products, making them discoverable and easily citable. Over the next three years, in response to NASA's efforts supporting interdisciplinary research and Open Science initiatives, the ADS will greatly expand its coverage of the literature, and will develop a new portal unifying access to the fields of Astrophysics, Planetary Science, Heliophysics, and Earth Science. It will also cover NASA funded research in Biological and Physical Sciences. The planned system will combine a scalable, discipline-agnostic core with a set of discipline specific knowledge centers which will curate and enrich its content using deep subject matter expertise from the NASA Science divisions. In this talk I will provide an overview of the ADS system, its distinguishing features, and then focus on our efforts to support and promote the FAIR principles as part of NASA's Year of Open Science initiatives.
An integrated hierarchical wide-area augmentation for real-time GNSS positioning
Authors: Cui Bobin , Wang Jungang , Jiang Xinyuan , Li Pan , Ge Maorong , Schuh Harald
Published: February 2023

Due to the correlation between coordinates, atmospheric delays, and ambiguities, Precise Point Position with Ambiguity Resolution (PPP-AR) needs a long convergence time (around 20 min) to achieve cm-level accuracy. With the help of precise external atmospheric products, PPP-AR convergence time can be reduced to a few minutes or even instantaneously. However, a stable and continuous data transmission in real-time communication could be challenging in more expansive areas due to the massive amount of correction information from dense networks. In addition, data interruptions and switching reference stations also could cause discontinuity or anomalies in the real-time correction information. By combining both wide-area fitting functions and regional un-modeled corrections, we present an integrated hierarchical augmentation method, which could ensure reliable and precise positioning with less communication burden. The first level of the hierarchical model includes the satellite-wise slant ionospheric delay and tropospheric Zenith Wet Delay (ZWD) wide-area fitting models, which provides an essential correction with few model coefficients covering a larger area. Moreover, the residual unmodeled errors and phase residuals can be provided optionally, according to the communication capability and the user’s requirement. The newly developed augmentation mode extends from the current wide-area low-precision to the hierarchical-precision service, which relieves the communication burden and greatly reduces the dependence on the distribution of reference stations. We evaluate our model in the European region, using 103 EUREF Permanent Network (EPN) stations with 200 km station-spacing as modeling stations and 84 stations as external validation. The precision of the wide-area ionospheric and tropospheric delay models are 4.5 cm and 1.3 cm, respectively. With only the wide-area correction information, an convergence time (to 10 cm) of 2 and 3 minutes can be achieved for the horizontal and vertical components, respectively. Based on the magnitude of wide-area unmodeled errors, the optional unmodeled correction broadcast volume can be saved by 40-50% with respect to the legacy interpolation mode. Moreover, instantaneous ambiguity fixing within one to two epochs (1 min) can be achieved if the unmodeled residuals are exploited. Therefore, the proposed hierarchical augmentation mode satisfies different positioning demands of wide-area with low resource utilization.
Can remotely-sensed Earth’s entropy production reveal its ecological fitness?
Authors: Verstraeten Guido J.M. , Verstraeten Willem
Published: February 2023

It is straightforward to analyse Earth´s fitness in terms of controlling and governing global warming due to human emissions of greenhouse gasses. We make room, however, for Earth´s entropy production as criterion for ecosystems. Indeed, it is a remarkable claim of Nobel Prize winner Roger Penrose to explain life as the decelerating force of earth´s production of entropy. The amount of earth´s entropy production is included in the quantity of emitted energy in the form of long wave or thermal radiation governed by the Stefan-Boltzmann law about the radiance of black bodies. Here we want to analyse how biodiversity is a substantial parameter to explain the decline of the Earth´s entropy production.In the field of biodiversity Stephan Hubbel formulated the Unified Neutral Theory of Individual Migration of Life as an alternative to the widely accepted niche competition of species theory. According to Hubbel, species abundance is lognormally distributed within an ecosystem after dynamical equilibrium is reached. We examine the drift shift of species within neighbouring ecosystems by analysing the day (DLSTG) and night land surface temperature (NLSTG) gradient.  By restricting the examined area to a honeycomb with cells of 1 km² the assumption of constant atmospheric pressure can be assumed and in consequence the enthalpy is reduced to the entropy variation. The latter can be derived from remotely-sensed mean day and night land surface temperatures (LST).By interpreting the entropy variation in terms of the statistical Shannon entropy formula wherein we import the lognormal distribution of species abundance, the entropy variation in the studied time interval is proportional to the difference of the natural logarithm of the respective standard deviations of the former and the latter species distribution function. Increased (decreased) entropy corresponds to a negative (positive) rate of biodiversity of the study area.Hubbel´s area meta-community dynamics and the entropy production of the area under consideration and its surroundings provide a diversity number within the area. By integrating the mosaic of ecosystems over an extended almost isolated area (peninsula, insula, subcontinent) the decline or increase of entropy production gives a substantial support for Earth´s fitness for biological life. Preliminary, we aim at applying MODIS 1 km² day and night LST data on the area of South-western Finland to explore the idea of entropy variations.
Mediating Airborne Birch Modelling and Forecasting
Authors: Verstraeten Willem W. , Bruffaerts Nicolas , Kouznetsov Rostislav , Sofiev Mikhail , Delcloo Andy
Published: February 2023

Air pollution contributes to increased mortality and lower quality of life. It imposes additional distress on people suffering from respiratory diseases such as pollinosis. A quarter of the adult population and a third of all children in Europe are estimated to suffer from airborne allergenic pollen. In the future even more people might be subjected to pollen allergies since changes in climate and land-use tend to increase the amount of allergenic airborne pollen and prolong the pollen seasons. Good pollen mitigation measures may ease the symptoms but it requires proper knowledge on the modelling and forecasting of allergenic pollen in the air.We start from the setup of the pollen transport model SILAM (System for Integrated modeLling of Atmospheric coMposition), driven by ECMWF ERA5 meteorology in a bottom-up emission approach for the period 1982-2019 for the Belgian territory. The dynamic vegetation component in the pollen transport model is determined by pollen emission source maps which have to be ingested in the model for every pollen season. The used maps are derived by merging multi-decadal datasets of spaceborne NDVI with forest inventory data in a Random Forest statistical framework.Here we study the impact of spatially-varying pollen emission sources on the modelled airborne birch pollen levels compared with in-situ observations in a Monte-Carlo approach. Preliminary analysis indicates that by selecting the model scenario corresponding with median pollen levels, the correlation between the modelled and observed pollen levels increases with 16%. We show the importance of ingesting the appropriate pollen emission source map when the modelling and forecasting of airborne birch pollen levels is aimed for. Finally, we review methods to relate the pre-pollen season meteorology or vegetation state on the birch pollen loads of the up-coming season as tool for selecting the best emission source map in the forecasting framework.
Lessons learned from the EUREC4A-OA experiment on the impact of ocean small scales on air-sea interactions in the Northwest Tropical Atlantic
Authors: Speich Sabrina , Karstensen Johannes , Reverdin Gilles , Olivier Léa , Fernandez Pablo , L'Hégaret Pierre , Coadou Solange , Laxenaire Rémi , Zhang Dongxiao , Gentemann Chelle , Landschutzer Peter , Boutin Jacqueline , Bellenger Hugo , Pasquero Claudia , Meroni Agostino , Borgnino Matteo , Acquistapace Claudia , Bopp Laurent
Published: February 2023

EUREC4A-OA is a large international project, connecting experts of ocean and atmosphere observations and modelling to enhance the understanding of key ocean and air-sea processes at the and to improve the skill of forecasts and future projections.The core of EUREC4A-OA has been a one-month (Jan/Feb 2020) field study in the western tropical North Atlantic Ocean where high-resolution, synchronized observational data have been collected using cutting-edge technology on ships, airplanes and autonomous vehicles. EUREC4A-OA investigates heat, momentum, water and CO2 transport within the ocean and exchanges across the air/sea interface using innovative high-resolution ocean observations and a hierarchy of numerical simulations. EUREC4A-OA focuses on ocean dynamics at the small-scale (0.1–100 km) and related atmospheric boundary layer processes. EUREC4A-OA is centered on the tropics where the primary external time scale affecting air-sea exchange is the diurnal cycle. However, the internal ocean and atmosphere dynamics convolute the diurnal, synoptic, seasonal and longer time scales to climate variability.The talk will present some of the results we obtained so far from the observations collected during the field experiment and from numerical simulations. The analyses carried out revealed with unprecedented detail the particular characteristics of the ocean small-scale dynamics, enlightening that such scales are also very active in the tropical regions and not only over the mid and higher latitudes ocean.  Observations and models also unveil that the ocean small scales is important in contributing to the exchanges of heat, freshwater and CO2 between the ocean and the atmosphere. Moreover, the evaluation of the intensity of the coupling between the ocean and the atmosphere assessed from data and high-resolution simulations show that they are very important and intimately linked with the 3D structure of the small-scale ocean dynamics. The project has also provided preliminary results in terms of parametrization of different processes influencing the ocean and atmosphere exchanges that have been uncovered by the EUREC4A-OA field experiment. Notably a better representation of the small-scale freshwater patches due to precipitation has been introduced in the French Earth-System model that improves the overall simulations of air-sea interactions and clouds. A similar parametrization is now been introduced to take into account these physical processes in air-sea fluxes of CO2.
BPCA-derived PyC may reflect fire signals over regional scales from the western Amazon Basin fire record
Authors: Lyu Jing , Zimmerman Andrew , Bush Mark , McMichael Crystal
Published: February 2023

Fire alters the biogeochemical cycling of important elements, plays a role in climate change, and shapes the composition of global biological communities. Detection of past fires has long been used to reconstruct human settlement and climate records. Charcoal and phytolith abundance has been the most commonly used paleofire proxies but may only represent evidence of local fires. Chemical analyses of pyrogenic carbon (PyC) have been more recently used, but are also not without controversy. Thus far, very few intercomparisons of these proxies have been conducted. Here, the fire records contained in soil and lake sediments of Western Amazon (at lakes Ayauchi, Parker, Gentry, and surrounding regions) were determined by charcoal microscopy, chemical thermal oxidation (CTO), and benzene polycarboxylic acids (BPCA) molecular biomarkers. Charcoal represented a smaller portion of PyC and, with its patchy distribution, likely indicated local or larger regional fire events. With a median value of about 15% of organic carbon, PyC via CTO oxidation was of the highest concentrations, which suggests a larger PyC detection window and lower sensitivity of reflecting regional fire. With a median value of about 3% of organic carbon, the BPCA-derived PyC distributions bore the closest resemblance to both spatial and temporal regional fire variations, established via archeological, pollen and phytolith records, thus may be a more sensitive indicator of fire over larger regional scales. Molecular ratios of BPCA molecules in Lake Ayauchi soils indicated higher temperature fires (> 600°C) and suggested a history of more human occupation and human-caused fire in the Lake Ayauchi region compared with the Lake Gentry & Parker region. However, our findings suggest that the use of a combination of fire proxy methods provides a fuller picture of the fire history of a region than any single approach. Establishing a better understanding the differences in the information provided by various paleofire proxies will allow a more complete understanding of the drivers, history and ecological and biogeochemical effects of fire, both regionally and globally.
Sediment controls on the transition from debris flow to fluvial channels in steep mountain ranges
Authors: Neely Alexander , DiBiase Roman
Published: February 2023

Steep channel networks commonly show a transition from constant-gradient colluvial channels associated with debris flow activity and concave-fluvial channels downstream. The trade-off between debris flow and fluvial erosion in steep channels remains unclear, which obscures connections among topography, tectonics, and climate in steep landscapes. We analyzed steep debris-flow-prone channels across the western US and observe: 1) similar maximum channel gradients across a range of catchment erosion rates and geologic settings; and 2) lengthening colluvial channels with increases in sediment grain size. The correspondence between sediment grain size and colluvial channel length led us to test a hypothesis that steep channel gradients are controlled by thresholds of motion for mass-wasting failure of channel bed sediment and thresholds of sediment motion by fluvial entrainment. We calculated discharges needed to mobilize sediment by both mechanisms across channel networks in the San Gabriel Mountains (SGM) and northern San Jacinto Mountains in southern California (NSJM). Across steep colluvial channels in both landscapes, sediment is more likely to be mobilized by mass-wasting processes, which are less-sensitive to sediment grain size, in agreement with observations from imagery bracketing storms. Discharges with decadal recurrences are below fluvial entrainment thresholds but above mass-wasting entrainment thresholds for D50 (median) sediment sizes in colluvial channels. In lower-gradient concave channels downstream, discharges in decadal storms exceed fluvial entrainment thresholds but are lower than mass-wasting entrainment thresholds for D50-sized sediment. In both landscapes, fluvial channels progressively steepen downstream compared to gradients needed to mobilize sediment cover, which we interpret to reflect downstream increases in sediment flux. Coarser sediment supply in the NSJM than the SGM increases threshold discharges needed to mobilize sediment by fluvial entrainment, which increases total channel relief in the NSJM by (1) extending colluvial channels shaped by debris flows and (2) increasing fluvial channel gradients. Together, our analyses show how differing sensitivity of fluvial and debris flow processes to sediment grain size impacts the partitioning of colluvial and fluvial regimes in headwater channel networks.
'How healthy is my soil?' – A soil care app
Authors: Berglund Örjan , Berglund Kerstin , Bjuréus Anna
Published: February 2023

Soil structure and soil health depend on many physical, chemical and biological factors that interact in a complex way and can be hard and expensive to measure. In order to develop a tool to assess soil health and increase awareness among farmers, students and advisors of the importance of good soil health, a soil app, 'How healthy is my soil?' was developed. The EU Rural Development Programme funded the work.The mobile app is based on earlier research where a Field Test was developed. This Field Test has now been digitized and developed further into the free-of-charge mobile app 'How healthy is my soil?' and is available in Swedish and English for iPhone and Android phones.The app contains three major parts: 1. General questions about the field, 2. Soil health tests, and 3. A water infiltration test. All tests are easy to perform, and the equipment needed is generally found on a farm. You are step-by-step guided through the tests and asked questions that normally have three answers to choose from. Many pictures, films, and extra information help you interpret what you see. The results are presented and summarized at the end of each test. You can create a PDF with the results to be sent by e-mail to any address of your choice. The GPS and map function in the app makes it easy to find your way back to the same place later to follow up on soil improvement measures taken. More tests will be included in the app in the future.To get a first picture of how your soil generally works, choose a location representative of the field. To learn more about your soil, you can perform the test at more locations in the field, one that is better than your representative site and possibly a worse place. Then you can compare the actual soil health in the field to how it can appear at its best and worst.When you have done the tests for a field, you can think about possible mitigation measures based on the overall impression of the results. In the app, you get tips on various soil conservation measures to improve your soil and what you should avoid and minimize to achieve good soil health. You can make an action list for each field.All parts of the app can be performed separately, but together they give an even better picture of the soil health. By doing the tests regularly, preferably together with other farmers and advisors, it is possible to assess and monitor soil health. From this knowledge, it is possible to develop a long-term strategy to improve the soil of your fields.
Online Databases of Geologic Formations of Asia and Africa, with Display onto Plate Reconstructions for Any Time Horizon
Authors: Ogg Gabriele , Chang Sabrina , Du Wen , Ogg James , Mishra Suyash , Zahirovic Sabin , Ault Aaron , Mamallapalli O'Neil , Li Haipeng , Hou Hongfei
Published: February 2023

Two goals of the Paleogeography Working Group of the Deep-Time Digital Earth (DDE) program of the International Union of Geological Sciences (IUGS) are: (1) to interconnect national databases for all geologic formations, and to compile new online "lexicons" for countries that currently lack these; (2) to display the merged paleogeographic output for any time interval of these distributed databases onto appropriate plate tectonic reconstructions.Therefore, we have worked with regional and time-period experts to compile cloud-based lexicon databases for Asian and for select African regions. The new databases are currently completed for the Precambrian through Phanerozoic of Asia (ca. 4000 geologic formations as of March 2023) and of a part of Africa (Niger, ca. 200 formations). In addition to standard search criteria (age, region, lithology keywords, etc.), the user interfaces include map-based and stratigraphic-column navigation. The returned entries be displayed by-age or in alphabetical order. Many of the formation details include GeoJSON-formatted polygons of its regional extent. These enable plotting of the individual formations filled with their appropriate lithologic facies patterns onto any of three proposed plate reconstruction models with a single click. Or, if a geologic age is specified, a user can query all the linked regional databases to plot the locations of all formations (with lithologic facies patterns) that span that age onto a plate reconstruction model.Our team is currently working with the teams at Macrostrat (Univ. Wisconsin (Madison) and at One-Stratigraphy (DDE, IUGS) and with other geologic surveys to interlink their regional facies-time compilations for other global regions. The goal is to users to access the information on any geologic formation, and to obtain a view of the sediments and volcanics that were accumulating at any time on the ancient Earth.
Global emergence of compound climatic impact-drivers
Authors: Tan Zhetao , von Schuckmann Karina , Cheng Lijing , Speich Sabrina
Published: February 2023

Changes in health and sustainability of the ocean that provide goods and services for human well-being are closely linked to climate change. However, the ocean is exposed to a range of climatic impact-drivers (CIDs, e.g., temperature increase, sea level rise, oxygen depletion, acidification etc.) from global to local scale concurrently. These multiple CIDs make the ocean environment shifting from the normal condition, posing either positive or detrimental effects to ocean ecosystems. Therefore, detecting and understanding the combined effect of different CIDs (named compound CIDs in this study) is critical to further unravel diverse and adverse impacts on the ocean ecosystems.In this study, we analyzed compound CIDs from changes in the upper 2000m of the ocean temperature (T), salinity (S), and dissolved oxygen (DO) from 1960 to 2022, as well as surface pH changes from 1985 to 2021 by using several observation-based gridded products.We used a time of emergence (ToE) approach to investigate the long-term change of  the compound CIDs. First, to quantify the ToE of each CID, we investigated when and where the long-term change (signal) is significantly larger than the background variability (noise). The long-term change is quantified by the 20 years of low-pass filtering of global time series, and the background variability is quantified by the magnitude of annual-interannual variability of the local time series. Additionally, the uncertainty of ToE is defined by using an ensemble approach. With the ToE of individual CID available, we defined the regions where ToE of the compound CIDs can be detected if the change of more than one CID has already emerged. The results we obtained provide a new insight on the 3D changing ocean properties. They differ from previous studies that were limited to a subset of individual CID (e.g., sea level rise, chlorophyll-a, net primary production) or to the ocean surface only (e.g., SST).The analysis shows that, before 2021, for the upper 2000m, ~15% (±5%) of areas of global ocean has experienced the concurrent emergence of three CIDs (triple emergence), and ~30% (±8%) of global ocean has experienced concurrent emergence of two CIDs (double emergence) mainly in the Atlantic and northern Indian Ocean. Analyses at different depths reveal that ToE is stronger and starts earlier in deep layers (200-1300m) than in the upper ocean (0-200m) where the signal-to-noise ratio is lower (which may due to the strong interplay of the long-term change with natural variability).As marine ecosystems rely on an environment determined by multiple drivers (T/S/oxygen etc.), the investigation of the compound CIDs provides a more complete description (and quantification) of their long-term exposure to the CIDs (multiple stressors).
Climate Data Record Derived from Hyperspectral Sounders on AQUA, S-NPP and NOAA 2
Authors: Liu Xu , Wu wan , lei liqiao , Xiong Xiaozhen , yang Qiguang
Published: February 2023

Climate products are typically derived by performing spatial and temporal averaging of level-2 products. It is a time-consuming process to generate level-2 data products since modern hyperspectral satellite sensors have millions of observations each day with thousands of spectral channels for each observation.  Additionally, differences in level-2 retrieval algorithms for different satellite sensors can lead to errors in the climate products. We have developed a Climate Fingerprinting Sounder Product (ClimFiSP), which is derived from spatiotemporally averaged level-1 hyperspectral radiances directly.  The ClimFiSP algorithm uses consistent radiative kernels and a robust spectral fingerprinting method. It provides accurate data climate data fusion products from multiple satellite sensors. It eliminates or reduces the errors due to inconsistent L2 algorithms. We have applied this method to both AIRS and CrIS (on SNPP and on NOAA 20) data and generated two decades climate data records for atmospheric temperature, water vapor, cloud, trace gases, and surface skin temperature.  The ClimFiSP are being transitioned to NASA data centers for routine generations level-3 products.
Small-Scale (Sub-decameter) Plasma Density Irregularities in the Topside Ionosphere Using High-cadence Plasma Current Measurements on e-POP (Swarm-E)
Authors: Kastyak-Ibrahim Marzena , Howarth Andrew , White Andrew , Yau Andrew
Published: February 2023

We have performed a statistical analysis of small-scale (sub-decameter) plasma density irregularities in the topside ionosphere (at 325-1500 km altitude) using the high-cadence (1000 samples/sec) sensor surface current data from the Imaging Rapid-scan Ion Mass Spectrometer (IRM) onboard the Swarm-E / Enhanced Polar Outflow Probe (e-POP). The measured current consists of contributions from the ambient and non-ambient electrons and ions, and it is proportional to and serves as a proxy for the local plasma density. The high-cadence current data are averaged over time intervals up to 0.5 s (to facilitate comparison with previous studies) and the analysis is undertaken separately for the case of positive and negative net currents, respectively. We have developed and validated an algorithm to identify small-scale structures of plasma density depletions and enhancements, by finding local minima (depletions) and maxima (enhancements) in the measured current amplitude in each case.  We will compare and contrast the statistical distributions of small-scale plasma density depletion and enhancement structures down to sub-100 m scale, including their altitude, magnetic latitude, magnetic local time distributions and spectral characteristics.
Adaptive Forest Management under Climate Change: Some Criteria and Methods for Practical Purposes
Authors: D'Aprile Fabrizio
Published: February 2023

The effects of climate change on forests have often been underestimated in silviculture practiced in recent decades. Although the first attempts to draw attention to this complex problem appeared nearly half a century ago, the debate has been conceptual rather than experimental and applied. At first glance, the concerns were mainly related to sustainable forest management (SFM) issues, which obviously needed attention. Over time, the effects of climate change have mainly been considered within the SFM at different scales and objectives. Increased research and awareness of the importance of SFM under the pressure of climate change has led to the development of a clearer understanding which can be defined as 'adaptive forest management' to climate change. One of the characteristics of this complex discipline is to be characterized by the absence of stereotyped methods and/or objectives but to identify, verify, and adapt the methods to the different types of climatic and forest conditions present in the field.Therefore, this work shows some innovative forest management concepts, criteria, and preliminary results as adaptive methods related to forest planning and management approach under climate change conditions.
New approaches to processing radar altimetry waveforms over complex ice sheet topography
Authors: Huang Qi , McMillan Malcolm , Muir Alan , Phillips Joe , Slater Thomas
Published: February 2023

Sea level rise is among the most pressing environmental, social and economic challenges facing humanity, and requires timely and reliable information for adaptation and mitigation. The ice sheets of Greenland and Antarctica currently contribute approximately one third of global sea level rise, yet monitoring their coastal regions, which are often populated by numerous, highly dynamic outlet glaciers remains a challenge. One of the principal methods for monitoring ice sheet change is that of satellite radar altimetry, which provides a near continuous 30-year record of surface elevation and volume change. However, this technique can suffer from incomplete measurements and larger uncertainties over rugged coastal topography, where the instrument may fail to track the ice surface, or may record multiple distinct reflections within the illuminated ground footprint. In these situations, current Level 2 processing approaches can be sub-optimal, leading to inaccuracies being introduced into the resulting elevation measurements. Therefore, this study aims to explore new approaches to retrieving elevation measurements, comprising (1) multipeak waveform retracking and (2) a refined slope correction approach over complex regions. The developed approaches offer the potential for multiple elevation retrievals from a single waveform, and in turn the opportunity to increase both the reliability and quantity of elevation measurements.Within the study, these processing techniques were developed and evaluated across Russell Glacier and the whole Greenland as two typical test cases, based upon Sentinel-3 SAR altimeter acquisitions over ice sheet regions that exhibit complex topography. Laser altimeters including Airborne Topographic Mapper (ATM) and Ice, Cloud, and Land Elevation Satellite-2 (IceSat-2) data were used as independent validation sources. Ice sheet wide analysis showed that the developed approaches were capable of delivering equally high accuracy for multiple elevation retrievals with comparable dispersion (~ 1 m) but much lower bias (~ 0.5 m) and outliers (~ 4%) compared to standard Level-2 products (~ 4 m bias and ~ 20% outliers). The developed approaches have the potential to further extend the capability of satellite radar altimetry over complex glaciological targets, and to improve the accuracy and coverage of altimeter measurements across these regions.
Seasonal buildup and downward transfer of Warm Pool heat content by wind-driven ocean mixing
Authors: Gutierrez Brizuela Noel , Xia Yi , Xie Shang-Ping , Alford Matthew , Moum James
Published: February 2023

Ocean heat stored in the Western Pacific Warm Pool (WPWP) helps drive some of the foremost modes of weather and climate variability including ENSO, Intraseasonal Oscillations, and tropical cyclones. To understand the associated coupled mechanisms that regulate ocean temperature, we use reanalysis and a novel moored microstructure dataset yielding estimates of the turbulent ocean heat flux (Jq(z)) to describe how WPWP mixing is regulated by seasonal, intraseasonal, and synoptic-scale atmospheric disturbances. It is argued that observed variations in Jq(z) impact seasonal-to-synoptic trends in SST and mixed-layer depth. Jq(z) is weakest during Spring (dry season), when heat fluxes into the ocean (Qnet > 0) create a shallow mixed layer (ML) of warm water that lays undisturbed atop the seasonal thermocline. In the Summer, westerly winds associated with the Asian Monsoon create favorable conditions for tropical depression-like (TD-like) storms, which in turn cause episodic spikes in Jq(z) that gradually deepen the ML and momentarily cool sea surface temperature (SST) while the background SST continues to rise. Towards the end of the summer, SST at our mooring was greater than 30.7 °C but rapidly dropped and stabilized below 29.5 °C after a strong pulse of the Madden-Julian Oscillation (MJO) cooled the upper ocean and deepened the ML for almost 15 days in a row. Enhanced upper ocean mixing continued to be episodic throughout the Fall as TD-like storms and intraseasonal disturbances moved over the mooring site. Mixing remained high throughout the Winter, when cold outbreaks forced the upper ocean at high frequencies and mean convective cooling (Qnet < 0) further contributed to mixing. A similar seasonality is observed at the thermocline level, where Jq(z) is enhanced by storm-driven near-inertial internal waves (NIWs) whose power peaks between Fall and Winter. While intraseasonal wind bursts had the greatest impact on near-surface mixing, synoptic disturbances generated greater-amplitude NIWs and thus had a greater potential to mix temperature gradients in the permanent thermocline. Lastly, we use reanalysis data to argue that storm-driven mixing shapes interannual relations between SST, storm activity, and the Asian Monsoon. 
New microbial sources of 2- and 3-methylhopanoids from anoxic, acidic, sulfidic hydrothermal springs
Authors: Mayer Marisa , Parenteau M. Niki , Evans Thomas , Jahnke Linda , Summons Roger , Madigan Michael , Love Gordon , Welander Paula
Published: February 2023

Biomarkers are membrane lipids that can record microbial inputs to the sedimentary rock record and can provide a longstanding record of microbial life on Earth. Hopanoids, cyclic triterpenoid membrane lipids, are some of the most abundant bacterial lipid biomarkers on Earth. Previously, we identified the production of 3-methylhopanoids (3-MeBHPs) in Rhodopila sp. LVNP - a novel purple non-sulfur (PNS) anoxygenic phototroph we isolated from an acidic (pH 3.9) sulfidic spring in Lassen Volcanic National Park. We also detected 3-MeBHPs in a closely related microbe (Rhodopila globiformis) isolated from a similar spring in Yellowstone National Park (pH 3.4). We went back to the environments from which these cultures were isolated and performed lipid analyses on microbial consortia and sediments in situ to link the laboratory studies to source organisms in the natural environment. We used liquid chromatography mass spectrometry (LC-MS) analyses to characterize the intact bacteriohopanepolyol (BHP) profiles, 16S rRNA microbial community composition, and metagenomic evidence of methylated hopanoid production potential in the two acidic springs. Using the combination of these techniques, we detected a multitude of novel source organisms for both 3-MeBHPs and 2-methylhopanoids (2-MeBHPs). 3-MeBHPs are traditionally associated with oxygen requiring methanotrophic and acetic acid bacteria and have long been considered a signal for aerobic methanotrophy in the rock record. 2-MeBHPs are traditionally associated with cyanobacteria and the origins of oxygenic photosynthesis. Previous studies have found organisms that are exceptions to this but are considered not environmentally relevant outside of laboratory studies. Our work shows production of these geologically important lipid biomarkers in an anoxic natural environment where no cyanobacteria and no methanotrophs are present. This work combines laboratory studies and environmental analyses, which led to the discovery of new source organisms for methylated hopanoids. New evidence of non-traditional source organisms in these anoxic environments may have implications for re-interpretations of the sedimentary rock record.
High-resolution simulation of Tropical Cyclone Debbie (2017):The current and future changes in the inner-core structure and evolution during offshore intensification.
Authors: Deng Difei , Ritchie Elizabeth
Published: February 2023

Tropical Cyclone Debbie (2017) made landfall near Airlie Beach on 28 March 2017 causing 14 fatalities and an estimated US$2.67B economic loss and was ranked as the most dangerous cyclone to hit Australia since TC Tracy in 1974. In addition to the extreme flooding as TC Debbie moved onshore and down the east coast of Australia, it intensified rapidly just offshore from Category 2 to Category 4 in approximately 18 hours and finally made landfall as a Category 4 TC, causing widespread and disastrous damage. A high-resolution WRF simulation (1-km horizontal, and 10-min temporal resolution) is used to analyze the inner-core structure and evolution during the offshore rapid intensification period in the current conditions and potential future change. In current condition, Debbie’s a rapid intensification (RI) stage is characterized by three rounds of eyewall breakdown into mesovortices and re-development events. Each round of breakdown and re-establishment brings high potential vorticity and equivalent potential temperature air back into the eyewall, re-invigorating eyewall convection activity and driving intensification. The potential future changes in the inner-core structure and eyewall evolution will also be discussed using WRF with the Coupled Model Intercomparison Project Phase 6 (CMIP6) perturbed conditions to better assess the possible TC intensity change under different climate change scenarios.
Modeling the ionospheric delayed response to solar rotation period changes in EUV radiation
Authors: Vaishnav Rajesh , Jacobi Christoph , Schmölter Erik , Dühnen Hanna , Berdermann Jens , Codrescu Mihail
Published: February 2023

The thermosphere-ionosphere system changes significantly on various temporal scales due to the forcings from solar and geomagnetic processes, and the lower atmosphere. The 27-day variation caused by solar rotation is one of the most important modulating factors in the ionosphere. A robust feature in this context is the ionospheric lag of about 1-2 days in ionospheric parameters such as total electron content (TEC) and F2 layer peak electron density with respect to solar variations at the 27-day solar rotation period. Here, the ionospheric TEC provided by the International GNSS Service (IGS) and the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model were used to understand the delayed ionospheric response and the underlying physics. The O/N2 measurements from the imaging ultraviolet spectrograph Global-Scale Observations of the Limb and Disk (GOLD), the Global Ultraviolet Imager (GUVI), were also analyzed during the 2019-2021 period of low solar activity. The comparative study shows that the model successfully reproduces the delayed response of the ionosphere during low solar activity. The observed and modeled O/N2 ratio was found to be positively correlated with the solar EUV proxy (GOLD QEUV), with a lag of about 2 days, indicating a contribution to the ionospheric lag in TEC.Furthermore, the CTIPe model simulations show that the ionospheric time delay is significantly affected by various physical processes such as diffusion, photodissociation, solar and geomagnetic activities, and wave dynamics.
Using Predicted Ocean Angular Momentum for Earth Orientation 
Authors: Stamatakos Nicholas , Salstein David , McCarthy Dennis , Psiaki Mark
Published: February 2023

Previous investigations have shown the potential of enhancing the accuracy of estimates of the direction of the rotational pole and velocity of rotation of the Earth by applying atmospheric and ocean angular momentum data (based on global conservation of the angular momentum in the Earth system).  This poster is a continuation of previous efforts with additional and/or enhanced modeling of the atmospheric and ocean phenomena and, additionally, enhanced optimal smoothing techniques for combining these and other data to make improved and robust estimates.  The atmospheric and ocean data are to be provided by the US Navy Earth System Prediction Capability (ESPC) models, and this data will be combined with past geodetic observations from other inputs using a Kalman Smoother/Filter or other optimal estimation technique.
Impact of vegetation on the boreal summer monsoon precipitation over India: an energetics viewpoint.
Authors: Samuel Jerry B , Chakraborty Arindam , Paleri Anagha
Published: February 2023

The heterogeneities arising out of surface variabilities, land-sea contrasts, aerosol concentrations, and the influence of orography define the intricate characteristics of regional monsoon systems. The amount of precipitation India receives during the boreal summer monsoon season can be modulated by land surface processes due to its influence on moisture availability and atmospheric stability. This study investigates the impact of vegetation changes on the seasonal mean precipitation over Indian land using fully coupled global climate model (GCM) simulations with idealized land cover. In addition, an  energetics framework is employed to unravel the physical mechanisms/pathways connecting vegetation and rainfall. In general, evaporation enhances with an increase in forest cover. However, this does not translate to a similar increase in all-India averaged precipitation. Using the energetics approach, we find that precipitation changes primarily happens via three different thermodynamic pathways. We also find the regions where each pathway is dominant. The relative dominance of these pathways in various areas leads to spatial inhomogeneities in the precipitation response due to vegetation changes. Human intervention, including agricultural expansion, has reshaped the landscape of India in the last century, altering the nature of land-atmosphere interactions. The results from this study, that land cover plays a significant role in modulating the regional characteristics of seasonal monsoon precipitation, are particularly important in this context. The findings in this study also have broader ramifications since the dominant region-specific mechanisms identified are expected to be valid for other forcings and are not just limited to the scenarios considered here. A unified framework connecting these various forcings with monsoon variability would be of great practical importance, and the present study is an advancement in this regard.
Study on the earth and rock-filled dam settlement monitoring in multi-SAR interferometry
Authors: Liu Jie , Li Tao , Ma Sijie , Dan Qiang , Jiang Weiping
Published: February 2023

In China, there are nearly 100,000 earth and rock-filled dams, which are essential water conservancy facilities for agricultural irrigation, food security, flood controlling, and power generation and so on. The periodically deformation monitoring for those dams are the key criterion to evaluate their safety. However, traditional surveying technologies such as levelling, total station and GNSS and some inner sensors (like fibers) for continuous real-time monitoring are costly and require large amounts of human resources.In this paper, we evaluate the ability of the currently operating X-band and C-band SAR sensors on dam deformation monitoring and propose a conversion parameter to retrieve the dam consolidation settlement. According to the earth and rock-filled dam post-construction settlement mechanism, a dam settles due to the compaction effect of filling earth in the dam. While in SAR geometry, only the line-of-sight projection of the slope surface deformation is visible along the radar beam. In order to convert the deformation from SAR geometry to real 3D geometry, we proposed a method for converting the dam post-construction deformation from SAR light of sight to vertical direction, based on the geometrical parameters of the dam and the SAR sensor.The experiments by both simulated and real cases in the Gongming reservoir of Shenzhen city in china are utilized to compare the deformation monitoring capability of various SAR sensors with different resolutions and to demonstrate the applicability of deformation conversion method. The simulation results show that the foreshortening of the slope greatly affects the slope deformation retrieval, for the small earth-rock filled dams with axis being parallel to the SAR heading direction, the conversion parameter between two slopes of dam maybe differ than 2~3 times. The real experiments, by both the differential interferogram and time series analysis, based on TSX, CSK and Sentinel-1 data in Shenzhen Gongming reservoir show that the high-resolution data have more precise results. The time series analysis of multi-SAR data from 2017 to 2021 are used to show full processing of the dam post-construction settlement. For the small dam which is nearly 30 meters high and 200 meters long, With the 1~3 meters resolution of TSX and CSK data, we can retrieve the dam  settlement from both the cross-section profile and the axis section profile. The Sentinel TOPS data sets with low resolution cannot fully retrieve the dam settlement and the results are underestimated.
Appropriately representing convective heating is critical for predicting catastrophic heavy rainfall in 2021 in Henan Province of China
Authors: Xu Mingyue , Zhao Chun , Gu Jun , Feng Jiawang , Li Gudongze , Guo Jianping
Published: February 2023

An unprecedented heavy rainfall event occurred in Henan Province of central China during 19-20 July 2021. To investigate the impacts of predicted large-scale circulation on the regional convection-permitting prediction of this event, two sets of nested experiments with different convective parameterizations (GF and MSKF) in the outer domain and at convection-permitting resolution in the inner domain are performed with the Weather Research and Forecasting (WRF) model. The analysis found the prediction of “21.7” rainstorm at convection-permitting resolution in the inner domain is largely affected by convective scheme in the outer domain. The large-scale circulation forcing from the outer domain with different convective schemes is significantly different, which ultimately affects the circulation and precipitation in the refined region through lateral boundary forcing. The difference in regional prediction at convection-permitting resolution can be mitigated by adjusting convective latent heat parameterization in the outer domain. This work highlights that appropriately parameterizing convective latent heat is the key to provide reasonable large-scale forcing for regionally predicting this catastrophic heavy rainfall event at convection-permitting resolution, which may also be applicable to other events and other regions.