The identification of a prospective groundwater recharge zone is crucial for supplementing groundwater resources. It's especially critical in the hard rock region, where groundwater is the principal source of potable water and is fast disappearing due to uncontrolled mining. The present study used a combination of modern methodologies and technologies to analyze the groundwater potential zone occurrence, including geographic information system (GIS), remote sensing (RS), electrical resistivity i.e. VES, and multi-criteria decision analysis (MCDA). Several thematic layers were prepared, including geomorphology, lineament density, drainage density, soil type, geology, rainfall, soil texture, elevation, and land use land cover (LULC), which were weighed according to their impact on the groundwater prospect zone. The analytical hierarchical process (AHP) was used in this study to apply normalization to relative assistance. Vertical electrical sounding was used to find water bearing formations/fracture zones at various points throughout the selected region. The five prospective groundwater prospect zones that were delineated using these methods have been classified as very low, low, moderate, high, and very high. The delineated high groundwater potential zones were found in the northeastern part and a little below the central region, while low to moderate zones were found almost evenly distributed all over the region. The acquired result was validated using well yield data, which showed a 72 percent accuracy with our delineated groundwater potential zone. Hence, the AHP model in the current work has outperformed the competition in terms of prediction accuracy.

V. S. Gokul 1,2,3., K. M. Sreejith4., G. Srinivasa Rao 5., M. Radhakrishna 1*., P. G. Betts 21 Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400 076, India.2 School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria 3800, Australia.3 IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai 400 076, India.4 Geosciences Division, Space Applications Centre, Ahmedabad 380 015, India.5 Department of Applied Geophysics, Indian Institute of Technology (Indian School of Mines) Dhanbad, Dhanbad 826 004, India (*Corresponding author:gokul.vs@monash.edu)AbstractThe Indian Ocean has the largest geoid anomaly, known as the Indian Ocean Geoid Low (IOGL). This long wavelength geoid depression has a magnitude of negative 106 m, and is centered south of India. The nature and depth of the sources causing this characteristic low are poorly constrained and has been the subject of debate. In this abstract, we focus on understanding the density contributions to the geoid low from the crust and upper mantle using joint analysis of geoid and gravity data along with published tomographic models in the region. Decomposition of geoid anomalies in the spectral domain indicate that mass anomalies below the upper mantle (> 700 km) contribute to 90% of the total geoid anomaly. In order to compute the upper mantle contribution to the IOGL, we used the Moho geometry and the crustal density structure from the 3-D gravity inversion, and the SL2013sv tomography model for the upper mantle density structure. The presence of density sources, which was not resolved in the modeling within the sub-lithospheric mantle is confirmed upon comparing the crustal and upper mantle (up to 700 km) geoid response below the IOGL with n=10 residual geoid anomaly. Integrated gravity-geoid 2-D modeling of the geometries of the anomalous sources located at the base of LAB and at a depth of 320-340 km, respectively, confirms that the contribution of density structures up to 700 km explains only the ten percent of the IOGL which matches well with the spectral decomposition results. This suggests that the lower mantle sources, such as paleo-subducted slabs or plume sources from the core-mantle boundary significantly contributes to the IOGL.

A document by Yuchen Lu. Click on the document to view its contents.

 Abstract ID and Title: 1147876 Role of soil in regulating runoff processes in Pine- and Oak-dominated headwater catchments of the Western HimalayasFinal Paper Number: H44H-02Presentation Type: Online Poster DiscussionSession Number and Title: H44H Runoff Generation Processes: Exploring Thresholds, Sources, and Pathways from Plot to Continental Scales II Online Poster DiscussionSession Date and Time: Thursday, 15 December 2022; 13:45 - 14:45Location: Online Only  

A document by Fabiha Rahman. Click on the document to view its contents.

A document by Kyle Manley. Click on the document to view its contents.

A document by Ayomide Hamzat. Click on the document to view its contents.

A document by Hesam Saeidi. Click on the document to view its contents.

Climate change and a growing global population pose ongoing threats to critical resources. As resources required by the agriculture sector continue to diminish, it is critical to leverage the emerging technologies and new solutions within the sector. New cultivation practices have emerged over the years, allowing food to be grown within urban areas. Greenhouses are versatile in the resources needed for their operation, as well as the foods that can be grown. While greenhouses provide a potential for a more constant food supply, there is a lack of optimization between the components. There are benefits to having modular components of a greenhouse, allowing for adjustments or repairs to singular pieces. However, there is inefficiency in the entire system, since each component functions without considering the others. To improve greenhouse efficiency, a closed-loop system can be introduced. A greenhouse is a closed system, and by repurposing, reusing, and recirculating resources, a greenhouse can evolve to have a closed-loop system. This enables the components of a system to share resources more effectively, communicate any systems changes that are required, and minimize waste outputs.This research explores the current technology in the space of agriculture and computer science to create a fully closed-loop system. The most noticeable system components are food waste, nutrient systems, water systems, growing media, and heating and energy. Not all components within a greenhouse can leverage the same artificial intelligence methods and techniques based on existing findings. There are methods in place that allow the components to interpret data gathered from the greenhouse and alter its operational patterns. There remains a lack in communicating this information to other aspects of the system to have it make informed data-driven decisions as well. One can optimize singular components thereby reducing resource reliance, to a certain threshold until it impacts the plant’s development and yield. When all the systems components’ resource needs and outputs converge the functionality of the system can be optimized to utilize resources at a higher efficiency. Results are indicative of very siloed and isolated research, exploring closed-loop systems within greenhouses, but not leveraging its full capabilities.

A document by Antony Joh Moothedan. Click on the document to view its contents.

The Hunga Tonga Volcano eruption launched a myriad of atmospheric waves that have been observed to travel around the world several times. These waves generated Traveling Ionospheric Disturbances (TIDs) in the ionosphere, which are known to adversely impact radio applications such as Global Navigation Satellite Systems (GNSS). One such GNSS application is Precise Point Positioning (PPP), which can achieve cm-level accuracy using a single receiver, following a typical convergence time of 30 mins to 1 hour. A network of ionosondes located throughout the Australian region were used in combination with GNSS receivers to explore the impacts of the Hunga-Tonga Volcano eruption on the ionosphere and what subsequent impacts they had on PPP. It is shown that PPP accuracy was not significantly impacted by the arrival of the TIDs and Spread-F, provided that PPP convergence had already been achieved. However, when the PPP algorithm was initiated from a cold start either shortly before or after the TID arrivals, the convergence times were significantly longer. GNSS stations in northeastern Australia experienced increases in convergence time of more than 5 hours. Further analysis reveals increased convergence times to be caused by a super equatorial plasma bubble (EPB), the largest observed over Australia to date. The EPB structure was found to be ~42 TECU deep and ~300 km across, traveling eastwards at 30 m/s. The Hunga Tonga Volcano eruption serves as an excellent example of how ionospheric variability can impact real-world applications and the challenges associated with modeling the ionosphere to support GNSS.

A document by Chang Liao. Click on the document to view its contents.

Thawing of permanently frozen ground (permafrost) has increased in recent decades with negative implications for human and non-human adaptation to climate change. Impacts include reduced ground stability, increased transportation risk, and changes in water availability. Direct measurements of permafrost active layer thickness (the depth of thawed ground overlying permafrost) are sparse. Measurements currently exist for a few hundred sites located primarily in the Northern Hemisphere supported by the Circumpolar Active Layer Monitoring (CALM) Program. The sparsity of direct active layer thickness measurements limits broad-scale understanding of changes in permafrost thaw and confidence in future projections. To address the sparsity of direct active layer thickness measurements, we developed a method to estimate active layer thickness change from streamflow measurements, which integrate processes over broad spatial areas and are more common than point-scale active layer thickness measurements. The method uses classical principles of hydraulic groundwater theory and nonlinear baseflow recession analysis, which sets it apart from prior methods based on linear recession analysis. The method is applied to catchments in the continuous and discontinuous permafrost zone of the North American Arctic containing co-located streamflow and CALM active layer thickness measurements. We find good agreement in the magnitude and direction of measured and predicted active layer thickness trends. This suggests that regional-scale estimates of active layer thickness change can be obtained from streamflow measurements, which may open the door to retrospective estimation of active layer thickness change in data sparse Arctic regions with short, sporadic, or even nonexistent ground-based active layer measurements.

A document by Robert L. McGraw. Click on the document to view its contents.

A document by Zahra Zali. Click on the document to view its contents.

The Laccadive-Chagos Ridge (LCR) is a prominent aseismic ridge in the Indian Ocean. The origin and nature of the crust beneath the LCR have been debated. Based on Ar-Ar geochronology of the volcanic basement rocks from ODP wells 713 and 715 from Chagos and Maldives ridges, a hotspot trail model was proposed for the genesis of the LCR. On the other hand, based on geophysical studies, the LCR has been inferred as a continental sliver/hyperextended continental crust which has undergone heavy underplating and Reunion hotspot volcanism. Even though these two different hypotheses differ on the genesis and nature of the LCR, both agree that the ridge experienced extensive Reunion hotspot trail volcanism, making the crust's nature challenging to decipher. We report Ar-Ar ages of two rhyolite rock samples from a well drilled on the Padua bank located on the northern extent of the Laccadive ridge. These acidic rocks are at a depth of ~1700m and ~2300m and underlie the Tertiary sediments forming the basement in this well. The previously determined K-Ar geochronology ages are 60.2 Ma and 102 Ma. The precise Ar-Ar dates of these rocks determined in the present study are 76.2 ± 0.4 Ma and 77.5 ± 0.5 Ma (2σ) respectively. These acidic rocks (78-76 Ma) coupled with onshore acidic rocks of the St-Mary's island (87-84 Ma) and Ezhimala (95-93 Ma) suggest continuous extension between the India and Laccadive ridge after the Indo-Madagascar continental breakup (88 ma). Contrary to the earlier hypothesis, the acidic rocks of Laccadive Ridge are older than the Reunion Plume trail volcanism (62-60 Ma). The geophysical and geochronological evidence suggests that the Laccadive ridge is continental in nature, and the volcanism predates the Reunion plume volcanism. These evidences suggest that the Laccadive Ridge is a continental thinned crust that has undergone rift-related volcanism rather than a hotspot trail.

Numerous deterministic and probabilistic techniques have been utilized extensively to examine the velocity distributions for open channel flows under the various flow and channel characteristics. It is generally known that traditional approaches such as logarithmic velocity laws and power laws furnish vertical velocity profiles for the wide channels (width-to-depth ratio > 5) only. Also, the accuracy of the traditional methods is highly parameter dependent which, in turn, is evaluated using empirical or semi-empirical relationships only. Owing to the limitations of the conventional approaches, the entropy concept is formulated probabilistically and applies to all aspect ratios (width-to-depth ratio). The prominent entropy types explored to date are Shannon entropy, Tsallis entropy, and Renyi entropy. Recently, Fractional entropy has been demonstrated to study the velocity distributions for the open channel flows. Laboratory measurements have been used to demonstrate the applicability and correctness of all the techniques in adverse channel bed slope conditions (Singh & Khosa, 2022). The measurements comprise the velocity data at the different adverse slope values. Finally, a rigorous comparative analysis for the estimated velocity profiles using the four generally used velocity laws and four entropy-based velocity distributions have been conducted, which showed that the information entropy-based methods are far better than the traditional techniques.

In Iran, both local and regional scale land-surface deformation has resulted from the decline in groundwater levels \cite{Motagh_2008}. Moreover, the gap between groundwater extraction and renewal is so large that the resulting short-term impacts are likely to be irreversible \cite{Olen_2021}.Here we use Earth Observation (EO) data to calculate vertical subsidence rates due to groundwater extraction in Tehran, Iran’s capital city. This data includes Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR); very high-resolution (VHR) Pléiades optical stereo imagery; and ICESAT-2 laser altimetry data.The Centre for Observing and Monitoring Earthquakes and Tectonics (COMET) Looking into Continents from Space (LiCSAR) automated processing system is used to process six years (2015-2021) of Sentinel-1 SAR acquisitions \cite{Lazeck__2020} for interferometric (InSAR) analysis. The system generates short baseline networks of interferograms. We also correct for atmospheric noise using the GACOS system \cite{Yu_2018a,Yu_2018} and perform time-series analysis using open-source LiCSBAS software \cite{Morishita_2020}. Vertical and horizontal (east-west) velocities are calculated and mapped to produce nationwide and regional velocity fields \cite{Watson_2022}. Preliminary results indicate maximum subsidence rates in Tehran exceed 100 mm/year.VHR Digital Elevation Models (DEMs) and laser altimetry ground returns are also used to calculate land subsidence rates in Tehran. By comparing rates calculated using all three EO techniques we aim to validate InSAR velocities whilst investigating and constraining the benefits, drawbacks, and biases associated with each technique. Phase bias \cite{De_Zan_2015}, for example, may be introduced to calculated InSAR velocities when using the LiCSBAS short baseline network strategy as subsiding regions in Iran are often vegetated cropland.Publishing the open-source COMET-LiCS Subsidence Portal was the focus of previous work (https://comet-subsidencedb.org/). The portal presents automatically processed LiCSAR Sentinel-1 interferograms and LiCSBAS velocity timeseries for 99 subsiding regions across Iran. Interactive tools allow stakeholders to make quick, critical assessments related to extents and rates of subsidence. Validating portal data using DEMs and laser altimetry is essential before expanding the portal to have a global focus.