Indirect Observations Research Articles

Maneuvering Object Tracking and Movement Parameters Identification by Indirect Observations with Random Delays

The paper presents an approach to solving the problem of unknown motion parameters Bayesian identification for the stochastic dynamic system model with randomly delayed observations. The system identification and the object tracking tasks obtain solutions in the form of recurrent Bayesian relations for a posteriori probability density. These relations are not practically applicable due to the computational challenges they present. For practical implementation, we propose a conditionally minimax nonlinear filter that implements the concept of conditionally optimal estimation. The random delays model source is the area of autonomous underwater vehicle control. The paper discusses in detail a computational experiment based on a model that is closely aligned with this practical need. The discussion includes both a description of the filter synthesis features based on the geometric interpretation of the simulated measurements and an impact analysis of the effectiveness of model special factors, such as time delays and model unknown parameters. Furthermore, the paper puts forth a novel approach to the identification problem statement, positing a random jumping change in the motion parameters values.

The Utility of Swords in Kandyan and Low- country Rituals

The sword, a distinctive weapon used in various countries, holds multiple utilities across cultures. Among them, rituals featuring swords are commonly found. Sword usage is also seen in folk rituals in Sri Lanka, which hold an important place in society. The main objective of this research was to explore how the sword, a destructive weapon with sharp edges, is integrated into local dance rituals in Sri Lanka. Accordingly, the ritualistic offerings and performances involving the sword, the utility, and the purpose of sword usage in folk rituals were examined. The research problem was whether the original intent and the functions of the sword are represented when it is employed as a ritualistic artifact or theatrical prop in rituals. Since the study followed an ethnographic research approach, it relied on field research in identifying the exact perspectives of the community regarding the usage of swords in rituals. Additionally, secondary sources located via library surveys were used to gain further insights to provide a nuanced analysis. Using Kandyan and Low-country traditions as the limitations of the study, direct and indirect observations of targeted rituals were done, and interviews were conducted with expert artisans. The data analysis revealed that in folk rituals, the sword serves multiple roles, i.e., as an ornament of deities; a ritualistic artifact; and theatrical prop. Moreover, evoking heroic sentiment and blessings are some of the purposes of using swords. However, some characters that enact devils also wield swords. It was also revealed that the use of the sword in the Kandyan tradition is relatively minimal compared to the low country tradition. This is because the prevalence of characters enacting gods and devils is high in Low country dance rituals. With the exceptions of ritual performances like Kadupaliya and Wina Kepeema, swords are not commonly used for sacrificial purposes. In conclusion, the use of swords in local dance rituals serves psychotherapeutic purposes in different ways and demonstrates its primary application in unique manners by symbolizing the original weapon.

Exploring the Intersection of Subliminal Perception and Digital Marketing

Abstract: Subliminal refers to stimuli that operate below the threshold of conscious perception. Subliminal advertisements target the subconscious, where consumers may not consciously assess the content. However, their impact becomes apparent through indirect observations, such as the influence on emotions, the effect on cognitive processes, the ability of consumers to consciously evaluate these ads, the level of excitement and engagement with characters portrayed in subliminal ads, and various other aspects. This research delves into the intersection of subliminal perception and digital marketing, seeking to unravel the subtle influences that impact consumer behaviour in the digital realm. By employing a comprehensive methodology that includes surveys, content analysis, and hypothesis testing, the study aims to explore how individuals perceive and respond to subliminal cues embedded in digital marketing content. Ethical considerations guide the research process to ensure transparency and consumer well-being. A sample size of 126 participants, encompassing both male and female youths aged 18-30, was selected from diverse professional and non-professional backgrounds. The findings contribute valuable insights into the complex interplay between subliminal perception and digital marketing strategies, offering implications for marketers aiming to enhance user engagement, brand perception, and overall effectiveness in the online landscape.

Models of Inter-Moult Period for Antarctic Krill - Lack of Progress and Promulgation of Unreliable Models Calibrated Using Indirect Observations

Aims: Two methods of calibrating regression models of inter-moult period (IMP) as a function of temperature exposure (T) for crustaceans, in particular, Antarctic krill (Euphausia superba) are reviewed in terms of both theoretical and empirical properties in order to make recommendations on the application of the methods and/or the use of the resultant fitted models. Methodology: The method and fitted model that used a meta-analysis of published results from laboratory-reared krill using means of directly observed IMP for a range of controlled, constant temperature regimes has valid theoretical and empirical support. The alternative used moult frequencies obtained as a “byproduct” of 5-d Instantaneous Growth Rate (IGR) experiments carried out at sea for which individual IMPs were not directly observed. Instead mean IMP given T and animal total length (L) was predicted using the moult frequencies disaggregated to binary data of moulted versus not-moulted as dependent variable in the calibration of a logistic regression on T and L. The shape of the daily development rate, R, the inverse of IMP, versus T response curve fitted using direct observations is a classical monotonically increasing curve whereas for combinations of sex/maturity classes the curves fitted using indirect observations are parabola-like with sexually dimorphic concavities of either up or down. Four sources of bias in predictions of mean IMP using the indirect observations and estimation method are described. One source due to an unrepresentative sampling frame can lead to large positive bias in estimated mean IMP based on theory which has been absent until now and that applies a discrete uniform distribution for next moult date corresponding to ideal asynchrony. This bias and that due to IGR experimental measurement error in T cannot be remedied. Conclusion: The indirect method and the corresponding fitted models are unreliable and should not be used.

Society of Radiologists in Ultrasound Consensus on Routine Pelvic US for Endometriosis.

Endometriosis is a prevalent and potentially debilitating condition that mostly affects individuals of reproductive age, and often has a substantial diagnostic delay. US is usually the first-line imaging modality used when patients report chronic pelvic pain or have issues of infertility, both common symptoms of endometriosis. Other than the visualization of an endometrioma, sonologists frequently do not appreciate endometriosis on routine transvaginal US images. Given a substantial body of literature describing techniques to depict endometriosis at US, the Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts to make recommendations aimed at improving the screening process for endometriosis. The panel was composed of experts in the imaging and management of endometriosis, including radiologists, sonographers, gynecologists, reproductive endocrinologists, and minimally invasive gynecologic surgeons. A comprehensive literature review combined with a modified Delphi technique achieved a consensus. This statement defines the targeted screening population, describes techniques for augmenting pelvic US, establishes direct and indirect observations for endometriosis at US, creates an observational grading and reporting system, and makes recommendations for additional imaging and patient management. The panel recommends transvaginal US of the posterior compartment, observation of the relative positioning of the uterus and ovaries, and the uterine sliding sign maneuver to improve the detection of endometriosis. These additional techniques can be performed in 5 minutes or less and could ultimately decrease the delay of an endometriosis diagnosis in at-risk patients.

Brittle faulting and tectonic stress history on the western margin of the Congo Basin between Kinshasa and Brazzaville: Implications for the evolution of the Malebo Pool and the Congo River

The history of brittle faulting and associated paleostress states has been investigated in the rapids of the Congo River at the outlet of the Malebo Pool between Kinshasa (Democratic Republic of the Congo) and Brazzaville (Republic of the Congo). The aim of this study was to unravel the Meso-Cenozoic tectonic evolution of the western margin of Central Africa, as well as to investigate the dynamic evolution of the Pool and the capture of the Congo Basin drainage system by the Lower Congo River through the Central African Atlantic swell that formed between the Congo Basin and the Atlantic Ocean. We reviewed the geological evolution of the Pool area using recent data and new field observations to develop a consistent stratigraphic model for both sides of the Congo River. We collected a significant amount of data faults and fractures in the early Paleozoic Inkisi arkosic sandstones, identified four successive data subsets and determined their related paleostress tensors trough an iterative process utilizing relative chronological indications. All paleostress states exhibit a a strike-slip faulting regime, with varying orientation of horizontal principal compression. The timing of faulting was constrained by indirect observations based on the updated understanding of the Pool's evolution. The geodynamic interpretation of the brittle stages considered potential sources of compressional stress arising from plate boundaries and from the oceanic ridge push. A polyphase brittle tectonic history was identified, characterized by the gradual appearance of newly formed faults and reactivation of the existing ones, leading to the gradual saturation of the host rock with fractures. The most recent event let to a significant imprint on the current landscape and is believed to have facilitated the connection of the drainage system of the Congo Basin to the Atlantic coast in the Oligocene period. The current stress state, determined from earthquake focal mechanisms, aligns with the most recent paleostress state identified determined from fault-slip data, displaying similar stress axis orientations but with consistent with a transpressional stress regime instead of a strike-slip one.

Adaptive anisotropic Bayesian meshing for inverse problems

We consider inverse problems estimating distributed parameters from indirect noisy observations through discretization of continuum models described by partial differential or integral equations. It is well understood that errors arising from the discretization can be detrimental for ill-posed inverse problems, as discretization error behaves as correlated noise. While this problem can be avoided with a discretization fine enough to decrease the modeling error level below that of the exogenous noise that is addressed, e.g. by regularization, the computational resources needed to deal with the additional degrees of freedom may increase so much as to require high performance computing environments. Following an earlier idea, we advocate the notion of the discretization as one of the unknowns of the inverse problem, which is updated iteratively together with the solution. In this approach, the discretization, defined in terms of an underlying metric, is refined selectively only where the representation power of the current mesh is insufficient. In this paper we allow the metrics and meshes to be anisotropic, and we show that this leads to significant reduction of memory allocation and computing time.

Experimental and Numerical Assessment of the Thermal Bridging Effect in a Reinforced Concrete Corner Pillar

This paper discusses experimental and simulated data regarding the thermal bridging effect in a reinforced concrete corner pillar, which belongs to a building dating back to the 1980s and located in Southern Italy. The thermal field determined by the concrete pillar corner has been evaluated, introducing an experimental procedure based on both direct measurements and indirect observations of the inner superficial temperature by means of thermal imaging techniques and surface temperature probes. Moreover, indoor and outdoor air temperature and relative humidity were measured to provide suitable boundary conditions in the numerical simulations, performed with a commercial software tool widely used in Italy based on 2D finite element techniques. The experimental measurements show that, at more than 50 cm from the corner, the surface temperatures become almost constant, meaning that the thermal bridging effect becomes less evident. However, the surface temperature in the corner is around 1.5 °C lower than in the undisturbed flanking walls. In terms of local heat flux, the discrepancy between simulations and measurements is below 3%. Finally, this paper verifies the effectiveness of External Thermal Insulation Composite System (ETICS) renovation in reducing the thermal bridging effect of the corner pillar. The results also include the calculation of the linear thermal transmittance with a series of relations available in well-known atlases for thermal bridges and show that these relations are more reliable in the case of uninsulated pillar than for the insulated one.

The inhibitor protein IF1 from mammalian mitochondria inhibits ATP hydrolysis but not ATP synthesis by the ATP synthase complex

The hydrolytic activity of the ATP synthase in bovine mitochondria is inhibited by a protein called IF1, but bovine IF1 has no effect on the synthetic activity of the bovine enzyme in mitochondrial vesicles in the presence of a proton motive force. In contrast, it has been suggested based on indirect observations that human IFI inhibits both the hydrolytic and synthetic activities of the human ATP synthase, and that the activity of human IF1 is regulated by the phosphorylation of serine-14 of mature IF1. Here, we have made both human and bovine IF1 which are 81 and 84 amino acids long, respectively, and identical in 71.4% of their amino acids, and have investigated their inhibitory effects on the hydrolytic and synthetic activities of ATP synthase in bovine sub-mitochondrial particles. Over a wide range of conditions, including physiological conditions, both human and bovine IF1 are potent inhibitors of ATP hydrolysis, with no effect on ATP synthesis. Also, substitution of serine-14 with phosphomimetic aspartic and glutamic acids had no effect on inhibitory properties, and serine-14 is not conserved throughout mammals. Therefore, it is unlikely that the inhibitory activity of mammalian IF1 is regulated by phosphorylation of this residue.

PEDAGOGICAL ANALYSIS OF AUGMENTED REALITYIN THE EDUCATIONAL ENVIRONMENT DURING STUDYING PHYSICS

The article describes an augmented reality collaborative physics study called PhysicsARLab. The augmented reality lab is hosted by a teacher, and pupils can join the lab using their mobile phones. All participants can interact with the augmented reality lab, and their actions can be observed in real-time by both the teacher and fellow pupils. To evaluate the proposed system, a user study involving 60 participants (30 female and 30 male) was conducted. The participants were ninth grade and tenth grade high school pupils, ranging from 15 to 17 years of age, with an equal distribution across the two academic groups. The study designed a combination of direct and indirect observations, along with multiple surveys, to collect both quantitative and qualitative data. The data analysis considered various perspectives, including the system's usability, the effectiveness of its collaboration functionality, and its impact on PhysicsARLab. The research findings provide insights into the usability and impact of the collaborative augmented reality PhysicsARLab environment. The results are showed on the system's effectiveness in promoting collaboration, its usability for conducting experiments, and its potential benefits for PhysicsARLab.

Being a Naturalist Guide in Bardiya, Nepal: Evolution and Retrospective Analysis

This article, dealing with the profession of guiding in Bardiya National Park, is based on a previous paper (Vouiller, 2022) recently published in Studies in Nepali History and Society (SINHAS, Kathmandu), highlighting data gathered in 2019 with that of 2021-2022. While I presented the guide profession as being a clever adaptation to modernity, as an ‘in-between’, I would like here to accentuate the role of social networks, the process of ‘’heroisation’’ that takes place, but also the importance of the senses and the reading of signs in the practice of the profession. Bardiya National Park, established between 1988 and 1989, hosts very little anthropological work, it is more the object of research from developmental or natural sciences. The PhD I am currently pursuing in social and political sciences in Belgium (ULiège) and France (EHESS), is based on more than one year of fieldwork in Bardiya. It aims to understand how humans adapt psycho-corporeally and socially to the proximity of the Park’s animals. I am working with participant observation, semi-directive interviews with the professions most in contact with the animals of the Park, direct and indirect observations of encounters and finally linguistic analysis of the terms used in the discourses and on social media.
 The guiding subject in Bardiya is complex and representative of very topical internal and political tensions. Based on part of my doctoral work, I hope to show some of the factors that I believe will determine the future of tourism and human-animal cohabitation in Bardiya.

Beyond hippos: Evidence of an introduced deer in Colombia

More than 18% of the cases of invasive mammals worldwide correspond to South America, including small rodents and large species such as deer and hippos. Among exotic mammals in Colombia, we can mention pigs (Sus scrofa), which are well established, mainly in the Orinoquía region of the country, and more recently, hippos (Hippopotamus amphibius) with a growing area of occurrence in the middle and lower basin of the Magdalena River in the inter-Andean zone. In May 2022, a spotted exotic deer was documented in the area based on direct and indirect observations (photographs and videos) of living individuals and a partial skeleton. The spotted pattern of the photographed adults (absent in native or other exotic deer) and the juvenile individuals and the shape of the antlers show that they are chitals (Axis axis), a species native to Asia. Compared with the white-tailed deer Odocoileus, the largest native deer species in Colombia, the Axis skeleton was one-third bigger, which corroborated the identification. According to local inhabitants’ communications, the number of Axis has increased, and groups of up to 18 individuals have been recorded. This is the first time that exotic deer have been documented in Colombia. Their presence may impact natural regeneration and competitively displace other native herbivores, which calls for the mitigation and control of the population since its establishment and dispersal can be cryptic.

TOWARDS WHEAT YIELD ESTIMATION IN PLANT BREEDING FROM INHOMOGENEOUS LIDAR POINT CLOUDS USING STOCHASTIC FEATURES

Abstract. The world relies heavily on wheat, corn, and rice for nutrition, with global challenges such as population growth and climate change threatening food security. To tackle this, plant breeding, supported by digital technologies, focuses on improving food quality and quantity. Currently, crop yield estimation uses indirect observations through hyperspectral data and spectral indices, such as NDVI, which suffer from low sensitivity in breeding scenarios. Terrestrial laser scanners (TLS) present an alternative, allowing observations of the quantity and morphology of wheat ears from point clouds, which are directly linked to grain yield. However, exploiting these observations under field conditions presents challenges, mainly due to reduced resolution and non-homogenous properties of point clouds. In response, we propose an approach for in-field wheat yield estimation using machine learning and stochastic features of TLS point clouds that are specifically handcrafted to be less sensitive to the abovementioned phenomena. This approach avoids the need for explicit 3D reconstruction of individual plants and plant organs. Our initial results show limited success in yield estimation when posed as a regression problem. However, when framed as a classification problem focusing on detecting top- and bottom-performing plant phenotypes, we achieved a promising accuracy of 84.4% and AUC of 0.93. While encouraging, these are only the first results under relaxed conditions and further work is needed to enhance practical applicability.

Data-Driven Distributed Information-Weighted Consensus Filtering in Discrete-Time Sensor Networks With Switching Topologies.

This article proposes a data-driven distributed filtering method based on the consensus protocol and information-weighted strategy for discrete-time sensor networks with switching topologies. By introducing a data-driven method, a linear-like state equation is designed by utilizing only the input and output (I/O) data without a controlled object model. In the identification step, data-driven adaptive optimization recursive identification (DD-AORI) is exploited to identify the recurrence of time-varying parameters. It is proved that for discrete-time switching networks, estimation errors of all nodes are ultimately bounded when data-driven distributed information-weighted consensus filtering (DD-DICF) is executed. The algorithm combines with the received neighbors and direct or indirect observations for the target node to produce modified gains, resulting in a novel state estimator containing an information interaction mechanism. Subsequently, convergence analysis is performed on the basis of the Lyapunov equation to guarantee the boundedness of DD-DICF estimate error. Simulations verify the performance of the DD-DICF against the theoretical results as well as in comparison with some existing filtering algorithms.

Imaging of the electrical activity in the root zone under limited-water-availability stress: a laboratory study for Vitis vinifera

Abstract. Understanding root signals and their consequences for the whole plant physiology is one of the keys to tackling the water-saving challenge in agriculture. The implementation of water-saving irrigation strategies, such as the partial root zone drying (PRD) method, is part of a comprehensive approach to enhance water use efficiency. To reach this goal tools are needed for the evaluation of the root's and soil water dynamics in time and space. In controlled laboratory conditions, using a rhizotron built for geoelectrical tomography imaging, we monitored the spatio-temporal changes in soil electrical resistivity (ER) for more than a month corresponding to eight alternating water inputs cycles. Electrical resistivity tomography (ERT) was complemented with electrical current imaging (ECI) using plant-stem-induced electrical stimulation. To estimate soil water content in the rhizotron during the experiment, we incorporated Archie's law as a constitutive model. We demonstrated that under mild water stress conditions, it is practically impossible to spatially distinguish the limited-water-availability effects using ECI. We evidenced that the current source density spatial distribution varied during the course of the experiment with the transpiration demand but without any significant relationship to the soil water content changes. On the other hand, ERT showed spatial patterns associated with irrigation and, to a lesser degree, to RWU (root water uptake) and hydraulic redistribution. The interpretation of the geoelectrical imaging with respect to root activity was strengthened and correlated with indirect observations of the plant transpiration using a weight monitoring lysimeter and direct observation of the plant leaf gas exchanges.

Diversity, abundance, and habitat utilization of medium and large-sized mammals in Debre-Libanos Monastery Forest, central part of Ethiopia

Abstract The present study aimed to estimate the diversity, abundance, and habitat utilization patterns of medium and large-sized mammals in the Debre-libanos Monastery forest, Ethiopia. The survey was conducted from December 2019 to October 2020, considering the wet and dry seasons. A stratified sampling design was applied, dividing the study area into four habitat types based on the vegetation composition and cover (i.e., Natural forest, Plantation, Cliff/Rocky, and Settlement). Both direct and indirect observations were used along the transect lines to identify mammal species. Indirect evidence included tracks, dens, droppings, hair, and other signs. Nineteen transect lines of 0.5‒1 km in length were established. The distance between transects was 200 m to avoid double counting. A total of 11 medium and large-sized mammal species belonging to 6 orders and eight families were identified during the study period. Carnivores and primates were the dominant orders, accounting for 36.4% and 27.3% of the species, respectively. Among primates, the Gelada baboon (Theropithecus gelada) is endemic to Ethiopia. The highest diversity of medium and large-sized mammals was observed in the natural forest during the dry season (Hʹ = 1.44), and the lowest diversity was recorded in the settlement during the dry season (Hʹ = 0.77). The abundance of different mammal species varied significantly from an even distribution (χ2 = 7344.9, df = 10, p < 0.001) and was not consistent among the four habitat types (Species × Habitat type interaction; Fisher-Freeeman-Halton exact test; χ2 = 649.3, df = 30, p < 0.001). High similarity in species composition was observed between the natural forest and plantation (SI = 0.94), whereas low similarity occurred between the cliff/rocky and settlement habitat types (SI = 0.18). Gelada baboon abundance was high; therefore, communities and government bodies must pay attention and conserve this species in the area.

Beyond the Frontlines: Assessing PPE Waste Disposal in Lahore's Major Public Hospitals During COVID-19 and its Environmental Consequences

The COVID-19 pandemic spread around the world like fire in a forest. Many preventative measures were suggested, among which one was the use of PPE. PPE was already being used in hospitals to prevent the spread of contagious diseases. The current pandemic led to an enormous increase in PPE usage, both in hospitals and domestic circuits. However, it has been observed that PPE waste is not being handled and administered appropriately in some major hospitals in Lahore, Pakistan. This mishandling can lead to the rapid spread of diseases, more specifically, the current pandemic, COVID-19. Our study aimed to describe the management of PPE waste in public hospitals. The data was collected by direct and indirect observations of staff in the hospital, including the ones in administration, and the way they managed the waste. The condition of infectious waste in the waste depots of hospitals was also observed and noted. It was observed that not all the hospitals were following the guidelines provided by the WHO about PPE waste. Segregation, storage and transportation were below Pakistan’s biosafety rules for 2015 and WHO standards. It could lead to many health and environmental problems. Our study highlights the need for staff training regarding segregation and the proper storage and disposal of hospitals' waste. Certain recommendations in this regard have also been reported to put a stop to the issue of PPE waste and its drastic consequences for the environment.

A comparative study on penetration mechanisms of drug-loaded carbon and boron nitride nanotubes through biological membranes by steered molecular dynamics simulations

Understanding the mechanism by which nanotubes penetrate cell membranes is challenging from multiple perspectives. As a drug delivery system, boron nitride nanotubes (BNNTs) have a similar structure to carbon nanotubes but with B–N bonds instead of C–C bonds. Through a remarkable series of direct and indirect observations within specific cells, these nanotubes are popularly attributed as superior penetrant into cell membrane. Suitable functional groups and polymers are often needed to enhance the biocompatibility and solubility of BNNTs and CNTs in biological media. In addition, to figure out the effect of functional groups, the nanostructures without functional groups were first examined together with their anticancer drugs (fluorouracil and letrozole). All partial charges of the drug and nanotube have been investigated through population analysis. After that, with a total of 40 simulations (MD and SMD simulations), various analytical techniques were employed to examine the interaction between drugs and nanotubes with POPE, which is a class of phospholipids existing in biological membrane, in aqueous media. Noteworthy among these techniques is the mean-squared displacement analysis to compare the diffusion rate of nanocarriers and the radial distribution function analysis, which was utilized to compare water concentrations surrounding nanotubes. Additionally, the stability of the drug within the nanotube was assessed through mass center distance analysis. The diffusion coefficients of the nanotube-membrane complex were compared against various chemical agents by employing mean squared displacement analysis. The findings of the study revealed that the tethering of tetra ethylene glycol results in the augmentation of the water molecules surrounding the nanotubes while simultaneously enhancing the durability of the drug being conveyed. Nonetheless, the addition of tetra ethylene glycol resulted in a reduction in the nanocarrier’s diffusion coefficient. Communicated by Ramaswamy H. Sarma

VS-Cambium-Developer: A New Predictive Model of Cambium Functioning under the Influence of Environmental Factors.

Climate changes influence seasonal tree-ring formation. The result is a specific cell structure dependent on internal processes and external environmental factors. One way to investigate and analyze these relationships is to apply diverse simulation models of tree-ring growth. Here, we have proposed a new version of the VS-Cambium-Developer model (VS-CD model), which simulates the cambial activity process in conifers. The VS-CD model does not require the manual year-to-year calibration of parameters over a long-term cell production reconstruction or forecast. Instead, it estimates cell production and simulates the dynamics of radial cell development within the growing seasons. Thus, a new software based on R programming technology, able to efficiently adapt to the VS model online platform, has been developed. The model was tested on indirect observations of the cambium functioning in Larix sibirica trees from southern Siberia, namely on the measured annual cell production from 1963 to 2011. The VS-CD model proves to simulate cell production accurately. The results highlighted the efficiency of the presented model and contributed to filling the gap in the simulations of cambial activity, which is critical to predicting the potential impacts of changing environmental conditions on tree growth.

Sensitivity of the MAR regional climate model snowpack to the parameterization of the assimilation of satellite-derived wet-snow masks on the Antarctic Peninsula

Abstract. Both regional climate models (RCMs) and remote sensing (RS) data are essential tools in understanding the response of polar regions to climate change. RCMs can simulate how certain climate variables, such as surface melt, runoff and snowfall, are likely to change in response to different climate scenarios but are subject to biases and errors. RS data can assist in reducing and quantifying model uncertainties by providing indirect observations of the modeled variables on the present climate. In this work, we improve on an existing scheme to assimilate RS wet snow occurrence data with the “Modèle Atmosphérique Régional” (MAR) RCM and investigate the sensitivity of the RCM to the parameters of the scheme. The assimilation is performed by nudging the MAR snowpack temperature to match the presence of liquid water observed by satellites. The sensitivity of the assimilation method is tested by modifying parameters such as the depth to which the MAR snowpack is warmed or cooled, the quantity of water required to qualify a MAR pixel as “wet” (0.1 % or 0.2 % of the snowpack mass being water), and assimilating different RS datasets. Data assimilation is carried out on the Antarctic Peninsula for the 2019–2021 period. The results show an increase in meltwater production (+66.7 % on average, or +95 Gt), along with a small decrease in surface mass balance (SMB) (−4.5 % on average, or −20 Gt) for the 2019–2020 melt season after assimilation. The model is sensitive to the tested parameters, albeit with varying orders of magnitude. The prescribed warming depth has a larger impact on the resulting surface melt production than the liquid water content (LWC) threshold due to strong refreezing occurring within the top layers of the snowpack. The values tested for the LWC threshold are lower than the LWC for typical melt days (approximately 1.2 %) and impact results mainly at the beginning and end of the melting period. The assimilation method will allow for the estimation of uncertainty in MAR meltwater production and will enable the identification of potential issues in modeling near-surface snowpack processes, paving the way for more accurate simulations of snow processes in model projections.