Monsoon onset over the South China Sea occurs in April--May, marking the start of the wet season over East Asia. Nevertheless, skillful prediction of onset timing remains an open challenge. Recently, theoretical studies using idealized models have revealed feedbacks at work during the seasonal transitions of the Hadley cells, and have shown that these are relevant to monsoon onset over Asia. Here I hypothesize that monsoon onset occurs earlier in years when the atmosphere over the South China Sea is already in a state where these feedbacks are more easily triggered. I find that local anomalies in lower-level moist static energy in the preceding Jan--March are well correlated with South China Sea Monsoon onset timing. This relationship remains consistent on decadal timescales, while correlations with other teleconnections vary, and is used to develop a simple forecast model for onset timing that shows skill competitive with that of more complex models.

Landfills require extensive aftercare to safeguard human health and the environment. This involves monitoring emissions like leachate and gas, maintaining cover layers, and managing leachate and gas collection systems. Researchers have explored methods to conclude or extend aftercare. Experimental programs in the Netherlands are testing stabilization techniques for landfill waste bodies. Quantifying emission potential, a key concept integrating various processes influencing emissions, is essential for managing and predicting landfill impacts. In this study we developed a stochastic travel time model based on water life expectancies. The model is used to predict leachate production rates and leachate chloride concentrations from landfill waste bodies. We present new data for long-term time series of leachate production and leachate quality for four different waste bodies in the Netherlands. Unknown parameters are quantified by matching model output to measured time series using Bayesian inference. Once parameter distributions have been obtained, we are able to describe the measured long-term leachate dynamics. By analyzing the parameters and evolution of model states, we obtain a deeper understanding of the water and mass balance of the waste bodies. We demonstrate that the model can be used to quantify the emission potential and the estimated values of total mass match data quantified by sampling from the waste body. The results confirm that emissions with leachate are dominated by preferential flow infiltrating from the cover layer. Similar results have been obtained by applying the model to datasets from four different waste bodies, demonstrating that the approach is generally applicable.

A document by David Isham. Click on the document to view its contents.

Path dependent corrections relative to traveltimes have been demonstrated to improve event locations. Using available global velocity models, direction-based station corrections can be estimated in a region without calibration data. In this study, traveltime corrections have been obtained for 117 broadband seismic stations around southern Thailand, Peninsular Malaysia, Singapore and Sumatra region of Indonesia. A total of 82,325 first-arrival waves are obtained from 15,212 earthquakes that have occurred around the Sumatra Subduction Zone over five decades (1964 – 2018). The dataset is a combination of arrival time data from the Bulletin of International Seismological Centre and waveforms from the Incorporated Research Institutions for Seismology. A newly developed algorithm for three-dimensional ray tracing is used to compute traveltimes and raypaths. The corrections are based on the IASP91/AK135 velocity models at four back-azimuthal directions. The estimated residuals in seconds (s) ranges from -2.15 to 2.25 s for stations distributed around southern Thailand and a range of -0.76 to 1.60 s for stations within Peninsular Malaysia. A range of 0.59 to 1.08 s for stations within Singapore and -1.52 to 2.46 s for stations distributed around Sumatra (in Indonesia). Station PSI in Sumatra Island recorded the highest number with 4877 arrivals. Stations LEM, KLM and KGM show consistent high residual values at all calculated angles and distances. The result of this study will support routine location of hypocentral parameters within the region. The scheme is being implemented for use in the forward computational process of seismic tomographic inversion in the study area.

Unsteady land-sea breezes (LSBs) resulting from time-varying surface thermal contrasts Δθ(t) are explored in the presence of a constant synoptic pressure forcing, Mg, when the latter is oriented from sea to land (α=0°), versus land to sea (α=180°). Large eddy simulations reveal the development of four distinctive regimes depending on the joint interaction between (Mg, α) and Δθ(t) in modulating the fine-scale dynamics. Time lags, computed as the shifts that maximize correlation coefficients of the dynamics between transient and the corresponding steady state scenarios at Δθ=Δθmax, are found to be significant and to extend 2 hours longer for α=0° compared to α=180°. These diurnal dynamics result in non-equilibrium flows that behave differently over the two patches for both α’s. Turbulence is found to be out of equilibrium with the mean flow, and the mean itself is found to be out of equilibrium with the thermal forcing. The sea surface heat flux is consistently more sensitive than its land counterpart to the time-varying external forcing Δθ(t), and more so for synoptic forcing from land-to-sea (α=180°). Hence, although the land reaches equilibrium faster, the sea patch is found to exert a stronger control on the final turbulence-mean flow equilibrium response. Finally, vertical velocity profile at the shore and shore-normal velocity transects at the first grid level are shown to encode the multiscale regimes of the LSBs evolution, and can thus be used to identify these regimes using k-means clustering.

Current state-of-the art procedures for studying modeled submesoscale oceanographic features have made a strong assumption of independence between features identified at different times. Therefore, all submesoscale eddies identified in a time series were studied in aggregate. Statistics from these methods are illuminating but oversample identified features and cannot determine the lifetime evolution of the transient submesoscale processes. To this end, the authors apply the Topological Feature Tracking (TFT) algorithm to the problem of identifying and tracking submesoscale eddies over time. TFT allows a user to identify submesoscale eddies as critical points on a set of time-ordered scalar fields and associate the points between consecutive timesteps. The procedure yields tracklets which represent spatio-temporal displacement of eddies. Thus the time-dependent behavior of submesoscale eddies can be studied. We analyze the submesoscale eddy dataset produced by TFT, which yields unique, time-varying statistics on this currently underexplored phenomenon.

We present observations on a new precursory phase of seismic waves scattered in the deep Earth. This phase arrives prior to the PKPab wave at epicentral distances larger than 155º, and we call it PKPab precursor. We show that the presence of the PKPab precursor is a necessary consequence of scattering in D’‘, which is the commonly accepted cause of the PKPdf precursor at distances smaller than 145º. PKPdf waves that propagate through the inner core should arrive before the PKPab precursor but those, are strongly attenuated in the inner core at frequencies between 4 Hz and 8 Hz used here, making the PKPab precursor the earliest teleseismic signal at distances larger than 155º. Calculated PKPab precursor sensitivity kernel shows that this phase is mostly sensitive to scattering along the closest PKPbc path between source and receiver. It can thus help to constrain the lateral distribution of heterogeneity along D”.

The opacity of clouds at Alert, Canada have been shown by measurements of their infrared irradiances to change with the day-to-day solar wind input to the global atmospheric electric circuit, as well as to the inputs of global thunderstorms and magnetic storms. These cloud changes appear to be the cause of surface pressure changes in the Arctic and Antarctic that have long been observed to correlate with the solar wind sector structure. We analyze large data sets of cloud irradiances and surface pressures, and find differences in the responses to 2, 4, or more sectors per 27-day solar rotation. There are seasonal variations, with sign reversal in the summer, which we interpret as due to changing geometry of solar insolation input. The correlation coefficients that were shown to be statistically significant at near the 95% confidence level for all-year, all sector types show further increases for just winter months and for just 2-sector intervals. The phase relationship of the pressure responses compared to those of the cloud responses are consistent but not understood. There are also interannual variations, whose cause has yet to be determined. A parameterization of the potential distribution near the magnetic poles and out through the high latitude ionospheric region affected by solar wind inputs has been made, giving correlations of IR irradiance and pressure with these parameterizations stronger than with those for the IMF B alone. The effects analyzed are an indication of more extensive influences of global atmospheric electricity on cloud microphysics and cloud development.

Future carbon neutral or low carbon economies will inevitably restore past climate regulating parameters.  The physics of past climates appears to be an ongoing research subject.  Past surface temperature variations were induced by changes in the size of green matter and amplified by the ocean.  Future climates may be managed by photosynthesis.

The impact of the model-output vertical resolution on the moist static energy (MSE) budget associated with the Madden-Julian Oscillation (MJO) is examined. To achieve this objective, we perform the MSE budget analysis employing reanalysis data at different vertical resolutions: raw output layers, six standard layers as stipulated by the CMIP6 model requirements, high resolution in the upper troposphere, and high resolution in the lower troposphere. Results show that the data with only six layers results in a significant budget residual, consistent with the CMIP6 models observed. Moreover, the data with high resolution in the upper troposphere capture more realistic moist processes than data with high resolution in the lower troposphere. The budget residuals amplify with the rainfall anomalies and correspond to an overestimated vertical MSE advection. The leading bias source is associated with a strong vertical gradient of mean-state dry static energy (DSE) in the upper troposphere, which interacts with anomalous vertical velocity and thus leads to more MSE transport. Unrealistic vertical profiles of mean-state DSE and convection are also observed in the CMIP6 models. Examination of the same analysis using the DYNAMO field campaign shows that budget residuals are evident in low vertical resolution data, yet they correspond to an underestimated vertical MSE advection. The results from these datasets indicate that existing MSE budget residuals in the CMIP6 models are partially attributed to the low vertical resolution data.

A document by Alexander Lipatov. Click on the document to view its contents.

Science-AI Symbiotic Group at Seven Square Academy, Naigaon was formed in 2023 with the purpose of bringing school students to the forefronts of science research by involving them in hands on research. In October 2023 a new project was started with the goal of studying the lunar surface by real-time observations and open source data. Twelve students/members from grades 8, 9, 10 participated in this research attempt wherein each student filled an observation metric by observing the Moon on various days with a Bresser Messier 150mm/1200mm reflector Newtonian telescope. After the observations were done, the members were assigned various zones on the lunar near side for analysis of geological features. Then a data analysis metric was filled by each of students with the help of Lunar Reconnaissance Orbiter Camera's/ LROC's quickmap open access data hosted by Arizona State University. In this short paper a brief overview of this project is given. One example each of observation metric and data analysis metric is presented. This kind of project has high impact for school science education with minimal costs. This project can also serve as an interesting science outreach program for organisations looking forward to popularise planetary sciences research at school level.

Porosity and permeability plays an important role in the investigation of the flow ability of unconventional rock. Unconventional rock such as shale gas has extremely low permeability due to nano-scale pores. Non-Darcy flow typically applies to any inertial flow where the Reynolds number is higher than 1. The study of non-Darcy flow in porous rocks by experiments carried out in the laboratory is consistently characterized by high costs and time-consuming procedures. In this study, a novel method called the lattice Boltzmann method, an alternative to the laboratory method has been used for the study of non-Darcy flow of shale gas. It provides matrix permeability from pore structure considering inertial flow which causes departure from Darcy’s law. The characteristics of non-Darcy flow are significantly influenced by the pore structure of a porous medium, with a more heterogeneous structure such as in the case of shale exhibiting a more rapid termination of Darcy flow. Two samples of shale as large as 5 mm of southern Karanpura were taken for this study. Computed micro-tomography images were acquired at 0.4 μm and 0.8 μm. The study of non-Darcy fluid flow in shale gas showed that as velocity increases, an inertial effect gets dominated in flow which results in a lowering of permeability. Earlier onset of non-Darcy behavior in complex structures is also investigated. Developing a complete understanding of the transport properties and developing an approach to assess the prospective gas flow is essential in informing the estimation of shale gas reserves and developing effective recovery strategies.

Upwelling and decompression of mantle plumes is the primary mechanism for large volumes of intraplate volcanism; however, many seamounts do not correlate spatially, temporally, or geochemically with plumes. One region of enigmatic volcanism in the ocean basins that is not clearly attributable to plume-derived magmatism are the Geologist Seamounts and the wider South Hawaiian Seamount Province (∼19°N, 157°W). Here we present new bathymetric maps as well as 40Ar/39Ar age determinations and major and trace element geochemistry for six remote-operated vehicle recovered igneous rock samples (NOAA-OER EX1504L3) and two dredged samples (KK840824-02) from the Geologist Seamounts. The new ages indicate volcanism was active from 90–87 Ma and 74–73 Ma, inferring that, in conjunction with previous ages of ~84 Ma, seamount emplacement initiated near the paleo Pacific-Farallon spreading ridge and volcanism continued for at least ~17 m.y. Geochemical analyses indicate that Geologist Seamounts lava flows are highly alkalic and represent low-degree partial mantle melts primarily formed from a mixture of melting within the garnet and spinel stability field. The ages and morphology infer the seamounts were likely not related to an extinct plume. Instead, we build upon previous models that local microblock formation corresponded with regional lithospheric extension. We propose the microblock was bounded by the Molokai and short-lived Kana Keoki fracture zones. Regional deformation and corresponding volcanism among the Geologist Seamounts associated with the microblock potentially occurred in pulses contemporaneous to independently constrained changes in Pacific Plate motion —indicating that major changes in plate vectors can generate intraplate volcanism.

This study examines the evolutionary trends in predatory adaptation among indigenous dog breeds from Asia. Through a review of literature and historical records, we investigate how selective pressures and human interventions have shaped behaviors and traits in breeds such as the Indian Pariah, Korean Jindo, and Chinese Shar-Pei. By analyzing hunting strategies, prey preferences, and morphological features, we aim to understand the influences of natural selection, domestication, and cultural practices on the predatory behavior of Asian dogs. This research provides insights into the unique evolutionary pathways of Asian predatory dogs and their implications for conservation and human-dog interactions.

Differences in slab dehydration and fluid transport influence the distribution of magmatism and seismicity in subduction zones. Southwest Japan, particularly Kyushu and Shikoku/Chugoku, exhibits significant along-arc variation in the spatial distribution of Quaternary arc volcanoes and adakites as well as sub-arc tectonic tremors. Using two-dimensional numerical modeling, we quantitatively evaluate melting and fluid transport via a weak hydrous layer on the slab interface since the subduction initiation to clarify the observed key differences. In Kyushu, our model shows that dehydration of the colder subducting slab is mostly completed at sub-arc depths of 80–120 km, triggering intense flux melting in the mantle wedge without slab melting for adakite and an absence of sub-forearc fluid percolation for tremors. Whereas, the model for Shikoku/Chugoku shows shallower sub-forearc dehydration of the warmer slab (<80 km), allowing less flux melting, slab melting for adakite, and sub-forearc fluid percolation for tremors.

This study takes a look into public health and its intersections with environmental justice through soil contamination. We studied four San Francisco neighborhoods– two low-income and two high-income. 25 soil samples were collected from each neighborhood, for a total of 100 samples. The samples were then tested with an X-Ray Fluorescence Analyzer (XRF) for toxic heavy metal contamination. The heavy metals tested for were lead, arsenic, uranium, and thorium. The two low-income communities chosen are Bayview-Hunter’s Point (HP) and Chinatown (CT), both of which are below the citywide median household income. The high-income neighborhoods are Presidio Heights and Potrero Hill, both above the citywide median household income. It was found that Potrero Hill (PoH) had the largest mean Pb levels at 274.2 ppm, with Presidio Heights (PH) having the second largest at 211.1 ppm, more than twice the California recommended maximum of 80 ppm. Meanwhile, CT and HP mean Pb levels were found to be at 76.3 ppm and 123.3 ppm, respectively. These findings point to the fact that the high percentage of pre-1980-built housing of PH, coupled with its high greenspace density, may be raising exposure rates. It was in 1978 when the usage of lead paint began to be reduced and in 2002 arsenic in housing construction. As a result of high greenspace, heavy metals can more easily leach into the soil instead of somewhere more low-contact (e.g. water). The high presence of these heavy metals as a result of older housing, coupled with ample space for it to be contained near people, may be why so much was found in neighborhoods with these attributes. The lower CT and HP Pb and As levels may be a result of the lower access to soil, as they both have lower greenspace density than the citywide average. This study uncovers a different way in which exposure to arsenic and lead can occur. Previous studies have mainly focused on more industrial neighborhoods, but our findings show that there are other aspects of a neighborhood that can make it high-risk. Our findings produced optimistic results about the soil safety of two industrial and high-density neighborhoods, HP and CT, while drawing attention to the unsafe heavy metal levels in PH and PoH soil.

This study reports on a dayside magnetic reconnection event with a moderate guide field (0.4 times the reconnecting magnetic field) detected by the Magnetospheric Multiscale (MMS) mission. The spacecraft traversed the compressed magnetospheric separatrix, observing cold ions with densities up to 10 cm-3 and a large magnetosheath density up to 150 cm-3. We provide a detailed analysis of current densities, generalized Ohm’s law, and energy conversion processes in both the spacecraft (J.E) and the fluid (J.E’) frames during the separatrix crossing. The normal electric field is directed away from the separatrix due to the cold ion drift on the magnetosphere side and to the magnetosheath ion drift in the presence of a guide field in the exhaust region. In the spacecraft frame, energy transfers from the plasma to the fields (J.E≈J⊥.E⊥<0) due to the convective field associated with the earthward motion of the magnetopause and the ion diamagnetic current associated with the large density gradient. In the fluid frame, energy conversion reverses due to the magnetic field-aligned current density and electric field produced by the divergence of the electron pressure tensor (J.E’≈J∥.E∥’). Additionally, we give insights into the local changes in electromagnetic, bulk flow, and thermal energies. We show that flow and thermal energy variations of the plasma are mostly driven by the compressible term of the electron pressure strain at the separatrix.