Atmospheric aerosol affects climate, ecology, visibility, and public health and has attracted widespread attention. The fraction of inorganic aerosols in the atmosphere is significant and constitute about one-third of fine aerosol mass. The sources and formation processes of inorganic nitrogen aerosols in the atmosphere are with great uncertainty and therefore their long-term field measurement is critical. This study conducted a year-round field measurement of TSP, PM2.5 and PM1.0 in five different sites (ZJK, CP, CY DX, and TJ) in the Beijing-Tianjin-Hebei region to determine the concentrations of water-soluble inorganic ions (WSIIs) and also the isotopic composition of inorganic nitrogen (δ15N-NH4+, δ15N-NO3-, and δ18O-NO3-) to explore the sources and formation processes. The seasonal variation of δ15N-NO3- and δ15N-NH4+ were reflective of the relative contributions of the main source and also the effects of meteorological conditions. The source apportionment identified fossil fuel combustion (38.2 ~ 50.6%), agricultural emissions (18 ~ 24.7%), biomass burning (16.3 ~ 22.7%), and road dust/soil (8.7 ~ 23.4%) as the main sources of inorganic aerosols in Beijing-Tianjin-Hebei region. The located sources and regional migration (or transboundary pollution) contribute to the level of inorganic aerosol pollution. In winter, the aerosol of this region was affected by the air mass coming from the northwest. While in spring and summer, the air mass was mainly from the South China. The low temperature and high relative humidity favored the formation of inorganic nitrogen aerosol, while solar radiation affected the formation processes of the inorganic aerosols by changing the oxidation pathway of NO3- and also accelerating the volatilization and dissociation of NH4NO3. This study highlighted the main source contributions of inorganic nitrogen aerosol by utilizing N and O isotopes composition. Also, this study attached great importance in understanding the effects of meteorological conditions on formation and the contribution of regional transport.

We analyze seismic waves that are repeatedly excited by small explosions at the summit of Stromboli volcano, Italy, to understand the source process of volcanic explosions. At the end of September 2016, we deployed five broadband seismometers at locations only 100-300 m away from the active craters. Conducting moment tensor inversion to the entire seismic signals at 0.05-0.2 Hz band, we locate the source centroids at a depth of 170 m and 150-200 m west/southwest of the crater where acoustic waves are excited. On the contrary, the source centroids of seismic waves at 0.2-0.5 Hz and 0.5-1.0 Hz bands, which are excited almost at the same time of explosion onset, are located close to the crater. We further conduct semblance analyses to the seismic signals from about 30 s before to the end of explosion. The results show that a small preceding phase about 10-20 s before the onset of each explosion, which is first detected by our very-close observation, is radiated from a depth of 170 m beneath the west of the craters. Then, the source moves about 50 m toward the active crater area just before an explosion. During the explosion, however, the source moves back to the location where the small preceding phase is excited. These spatio-temporal changes estimated by the two source location analyses reflect the lateral migration of magma and gas bubbles, which may be a large slug as presented in many previous studies, in the shallow magma reservoir beneath the crater area.

This study is motivated by the observation that after a wave breaking event in the ocean, the residual surface foam left in the wake of the breaker rapidly cools down. The relationship between the cooling foam and the characteristics of the breaking wave such as bubble plume dynamics, visible surface foam, and energy dissipation is investigated experimentally. Previous studies have suggested that the decay time of the visible foam can be used to determine the dynamics of the subsurface bubble plume, and to estimate the energy dissipation by the breaking process. But the foam decay process can be greatly affected by the surfactant concentration in the ocean and this effect need to be accounted for independently. We present a new approach that utilizes the thermal signature of the cooling foam to infer the breaking characteristics and is less sensitive to surfactant concentration. The experiments are conducted in a wave flume that is equipped with a piston-type wavemaker and is filled with salt water. In order to study the effects of surfactants on the cooling of the residual foam, two sets of experiments are carried out; In the first set clean salt water is used and in the second set, Triton X-100 at a concentration of approximately 200 mg/L is added to the water. Breaking waves are generated using the focusing wavepacket technique and are designed to cover a wide range of slopes and breaking intensities. The bubble plume and the surface foam are imaged using visible cameras and the surface temperature is captured using an IR camera with an overlapping field of view with the visible foam camera. It is observed that the average temperature of the foam initially increases after the passage of a breaking wave due to the disruption of the cool skin layer, but the foam starts to cool down soon after the bubble plume has subsided, and the foam regeneration is not sustained by the bubbles anymore. It is found that the time from the start of the breaking process to the onset of cooling of the foam (τcool) scales with the decay time of the bubble plume (τplume), energy dissipation, and the wavepacket slope of the breakers. It is also observed that the foam decay time is prolonged greatly by the presence of additional surfactants (consistent with the literature), but the bubble plume decay time and the onset of cooling of the foam are not significantly affected.

The analysis of extremes in climate models is hindered by the lack of statistics due to the computational costs required to run simulations long enough to sample rare events. We demonstrate how rare event algorithms can improve the statistics of extreme events in state-of-the-art climate models. We study extreme warm summers and heatwaves over France and Scandinavia with CESM1.2.2 in present-day climate. The algorithm concentrates the simulations on events of importance, and shifts the probability distributions of regional temperatures such that warm summers become common. We estimate return times of extremes orders of magnitude larger than what feasible with direct sampling, and we compute statistically significant composite maps of dynamical quantities conditional on the occurence of the extremes. We show that extreme warm summers are associated to wavenumber 3 hemispheric teleconnection patterns, and that the most extreme summers are related to the succession of rare subseasonal heatwaves.

The oceanic uptake of anthropogenic CO2 has resulted in acidification in surface and subsurface waters throughout the global ocean. We initiated acidification monitoring in the eastern part of the Tsugaru Strait, which connects the Sea of Japan and the North Pacific. Annual mean pH and CaCO3 saturation state decreased considerably throughout all depths at rates of 0.0030−0.0051 yr−1 and 0.017−0.036 yr−1 during 2012-2019, respectively. These rates of decrease are faster than those caused by increasing atmospheric CO2, and faster than those observed during previous research in the Sea of Japan and the North Pacific. The accelerated acidification is attributed to enhanced increase in dissolved inorganic carbon caused by elevated mixing of the upper and deeper waters from the Sea of Japan at the western part of the strait by the strengthening of the Tsugaru Warm Current.

Fractures play an essential role in formations with low permeability; however, fracture sealing significantly reduces the permeability of fractures. The mechanism of how fracture sealing impacts the macro-scale fluid flow is rarely investigated. Here, we simulate sealing in two- and three-dimensional orthogonal fracture networks and investigate the impact of sealing on the percolation of these fracture networks. We find that a small amount of sealing can prevent the formation of spanning clusters, which suggests that global connectivity is rarely realized. Without significant stress perturbations, most fractures are partially sealed and non-critically stressed, and they usually do not contribute much to the fluid flow. However, under a significant stress perturbation, such as hydraulic fracturing, the well-connected and critically oriented fractures become critically stressed and slide because of the increased pore pressure. Partially sealed and non-critically stressed fractures can also contribute to the fluid flow by enlarging the stimulated reservoir volume (SRV). We estimate the stimulated reservoir volume in two dimensions by dividing the target distance (LSRV) into two parts. One is the distance limiting generation of hydraulic fractures (ΔLh), and the other is the limiting distance of making natural fractures slide (ΔLs). A rough estimation yields an elongated shape of the SRV, which is consistent with observations from microseismicity maps.

We investigate the structure and evolution of multiphase ice-ocean interfaces (‘mushy layers’) and the implications for the geophysics and habitability of ice-ocean worlds. Understanding the potential diversity of these multiphase layers across solar system bodies provides insight into the potential rates and mechanisms of heat and solute transport between their respective oceans and ice shells - which remain largely unconstrained. Additionally, variations in mushy layer properties may drive diverse geophysical processes unique to individual bodies or that may vary regionally on an individual icy world. We explore mushy layer evolution by analytically solving for the thickness of a simplified ice-ocean mushy layer system. We investigate two dynamic regimes, one driven by molecular diffusion and one driven by convection of brine within the mushy layer. We analyze the impact of gravity, thermal gradient, and ocean composition on the thickness of mushy layers. Additionally, a perturbation analysis is carried out to investigate the existence of mushy layer steady states. We show that stable mushy layers exist when ice shells are thickening, suggesting that mushy layers are likely persistent and common features of growing ice shells and accretionary regions of ice-ocean worlds.

The study of impact craters on Earth has picked up high worldwide consideration, which can be done by studying the ground surface using remote sensing (satellite), geological outcrops, drilling holes and apply small-scale laboratory experiments trying to build the dynamic models of crater formation and by collecting geophysical data. In this work the near- crater sediments at the young Wabar crater field in Saudi Arabia has been investigated using the magnetic, EM, seismic, and GPR methods. The main targets of this research were exploring the possibility of any remnant major pieces of the meteorite, investigate the meteoroid direction, and map the deformation structure associate with the meteorite impact. Our results shows five different magnetic anomaly types and three layers at the subsurface. The maximum deformation due to the impact of the meteorite is about 25 m as shown by both the seismic traveltime tomogram and the 3D GPR model. Transient EM survey confirmed the geometrical characteristics of the major crater and locate a smaller crater (known as Philby-A). The magnetic survey shows no evidence of any major piece of the meteorite, however, it was used to trace ejecta material containing highly dilute magnetic material. The magnetic carrier is most likely spheres of metal incorporated in the black/green glasses. During the expedition, many small pieces of the meteoroid were found and collected for further geochemical analysis. Based on the geophysical findings, the meteorite direction was found to be from north to south.

The stochastic discrete fracture network (SDFN) model is a practical approach to model complex fracture systems in the subsurface. However, it is impossible to validate the correctness and quality of an SDFN model because the comprehensive subsurface structure is never known. We utilize a pixel-based fracture detection algorithm to digitize 80 published outcrop maps of different scales at different locations. The key fracture properties, including fracture lengths, orientations, intensities, topological structures, clusters and flow are then analyzed. Our findings provide significant justifications for statistical distributions used in SDFN modellings. In addition, the shortcomings of current SDFN models are discussed. We find that fracture lengths follow multiple (instead of single) power-law distributions with varying exponents. Large fractures tend to have large exponents, possibly because of a small coalescence probability. Most small-scale natural fracture networks have scattered orientations, corresponding to a small κ value (κ<3) in a von Mises–Fisher distribution. Large fracture systems collected in this research usually have more concentrated orientations with large κ values. Fracture intensities are spatially clustered at all scales. A fractal spatial density distribution, which introduces clustered fracture positions, can better capture the spatial clustering than a uniform distribution. Natural fracture networks usually have a significant proportion of T-type nodes, which is unavailable in conventional SDFN models. Thus a rule-based algorithm to mimic the fracture growth and form T-type nodes is necessary. Most outcrop maps show good topological connectivity. However, sealing patterns and stress impact must be considered to evaluate the hydraulic connectivity of fracture networks.

Orbit determination of probes orbiting Solar System bodies is currently the main source of our knowledge about their internal structure, inferred from the estimate of their gravity field and rotational state. Non-gravitational forces acting on the spacecraft need to be accurately included in the dynamical modeling (either explicitly or in the form of empirical parameters) to not degrade the solution and its geophysical interpretation. In this work, we present our recovery of NASA GRAIL orbits and our lunar gravity field solutions up to degree and order 350. We propose a systematic approach to select an optimal parametrization with empirical accelerations and pseudo-stochastic pulses, by checking their impact against orbit overlaps or, in the case of GRAIL, the very precise inter-satellite link. We discuss how parametrization choices may differ depending on whether the goal is limited to orbit reconstruction or if it also includes the solution of gravity field coefficients. We validate our setup for planetary geodesy by iterating extended lunar gravity field solutions from pre-GRAIL gravity fields, and we discuss the impact of empirical parametrization on the interpretation of gravity solutions and of their error bars.

Rice (Oryza sativa) is a major staple food crop in India occupying about 44 million ha (Mha) of cropped land in meeting food requirements for about 65% of the population. As water scarcity has become a major concern in changing climatic scenarios precise measurements of actual evapotranspiration (ETa) and crop coefficients (Kc) are needed to better manage the limited water resources and improve irrigation scheduling. The eddy covariance (EC) method was used to determine ETa and Kc of tropical lowland rice in eastern India over two years. Reference evapotranspiration (ETa) was estimated by four different approaches– the Food and Agriculture Organization-Penman-Monteith (FAO-PM) method, the Hargreaves, and Samani (HS) method, the Mahringer (MG) method, and pan evaporation (Epan) measurements. Measurements of turbulent and available energy fluxes were taken using EC during two rice growing seasons: dry season (January-May) and wet season (July-November) and also in the fallow period where no crop was grown. Results demonstrated that the magnitude of average ETa during dry seasons (2.86 and 3.32 mm d-1 in 2015 and 2016, respectively) was higher than the wet seasons (2.3 and 2.2 mm d-1) in both the years of the experiment. The FAO-PM method best-represented ETa in this lowland rice region of India as compared to the other three methods. The energy balance was found to be more closed in the dry seasons (75–84%) and dry fallow periods (73–81%) as compared to the wet seasons (42–48%) and wet fallows (33-69%) period of both the years of study, suggesting that lateral heat transport was an important term in the energy balance calculation. The estimated Kc values for lowland rice in dry seasons by the FAO-PM method at the four crop growth stages; namely, initial, crop development, reproductive, and late-season were 0.23, 0.42, 0.64, and 0.90, respectively, in 2015 and 0.32, 0.52, 0.76 and 0.88, respectively, in 2016. The FAO-PM, HS, and MG methods produced reliable estimates of Kc values in dry seasons, whereas Epan; performed better in wet seasons. The results further demonstrated that the Kc values derived for tropical lowland rice in eastern India are different from those suggested by the FAO implying revision of Kc values for regional-scale irrigation planning.

We propose a simple way to define a field-line-following, general curvilinear coordinate system for a general magnetic field. This definition of field-line-following coordinate system reduces to a usual definition of dipole coordinate system when the magnetic field is approximated by an axisymmetric dipole. In this way, it can facilitate the numerical implementation by enabling validation of various metric terms computed numerically against those defined analytically in the case of dipole field. Steps involved in grid generation are also sketched. Highly accurate results are obtained using the high-order ordinary differential equation (ODE) solver to solve the general magnetic field line equations. The accuracy and consistency of the numerical implementation are validated against analytical results in the case of a dipole field. Numerical results show that this field-line-following coordinate system for the general magnetic field, like the coordinates for the dipole field, is also an Euler potential or Clebsch type coordinate system.

Landslides pose a significant threat to society and infrastructure and their occurrence is projected to increase in many regions under the effect of climate change. There is an urgent demand for reliable monitoring of this natural hazard. The combination of spaceborne remote sensing data with state-of-the-art machine learning algorithms offers valuable tools for landslide detection in remote areas. However, a key limitation for the detection lies in the scale factor, especially for methods relying on pixel neighbourhoods. This study presents an innovative methodology which combines a spatial graph with SAR and multi-spectral change products. The graph integrates the flow direction based on the topography into the neighbourhood determination. This unique neighbourhood allows for the preservation of the unique shape and signature of an individual landslide. This paper compares the proposed graph neighbourhood to a common square window approach. Therefore, a RFC is trained with neighbourhood statistics from both approaches and applied to landslides of varying extent. A research area in New Zealand’s West Coast region is selected due to the continuous evolution of a single landslide over multiple events. The graph approach shows promising results, particularly for small-scale events which are successfully detected while being missed by the common window approach. Using the graph neighbourhood, we can even detect the smallest visible extent of the landslide at 2-3 pixels (30-45m) width. The main limitation of the proposed approach lies in the quality of the input data. Future work will focus on the improvement of the Sentinel-1 and Sentinel-2 pre-processing.

1 2-3 4 5 6 7 8 9 key points: paleoclimatology, biostratigraphy, paleoceanography The Calcareous nannofossil assemblages have been investigated at the uppermost Eocene ‒ lowermost Oligocene at Marun Oil Field in Dezful embayment (SW Iran). The studied interval mainly consists of marly shales, marlstones, and limestones. Seventeen genera and 36 species of calcareous nannofossil have been determined. Regarding the succession of nannofossil bioevents, the studied interval is ranging from late Eocene (Priabonian, CNE18/NP18) to early Oligocene (Rupelian, CNO2/NP22). High relative abundance of warm water taxa (such as Sphenolithus spp., Discoaster spp. and Helicosphaera spp.) is recorded at the late Eocene, while towards the Eocene ‒ Oligocene boundary (EOB), an increase in the relative abundance of cool and temperate taxa (such as Reticulofenestra spp., Cyclicargolithus floridanus, Dictyococcites bisecta and Markalius inversus) is identified. A marked decrease in abundance of warm water taxa along with a decrease in species diversity indicate the cooling event at the EOB at Marun Oil Field in Iran similar to other parts of the world.

The subduction of carbon and recycling to volcanoes affects planetary scale processes that set the composition of Earth’s surface and mantle environments. The largest flux of surficial carbon that subducts at trenches globally is sedimentary. This is paradoxical, as most carbonate dissolves and organic carbon oxidizes in the ocean before reaching the deep seafloor. Nonetheless, different events conspire to deliver variable fluxes of carbon, some of them large, to different trench sectors. Thus, sedimentary carbon subduction is not a global phenomenon – it is a regional one where heterogeneity rules. Here we have calculated the flux and isotopic composition of both incoming sediment and trench fill for organic and inorganic carbon at the world’s trenches. Our calculations are at the scale of kms along the trench, and so make predictions relevant to individual volcanoes as well as entire arc segments. A useful comparative metric is the carbon flux delivered by altered oceanic crust (AOC), which is a less variable input of largely inorganic carbon to all subduction zones. In some regions, subducting sedimentary carbon is much less than in the AOC unit subducts, for example, along the ~ 2000-km Tonga-Kermadec trench. Given the very high convergence rate, this region constitutes a large flux of carbonate with δ13C heavier than the mantle. At the other extreme, downgoing plates with km-thick turbidites deliver terrestrial organic carbon with δ13C lighter than the mantle. Trench segments that subduct >4X AOC carbon in sediments include the Nicobar Fan off Sumatra and the Aleutian and South Chile trenches. Regions with high biological productivity (Central America) and shallow seafloor (Hikurangi) supply large sedimentary carbonate fluxes with δ13C heavier than mantle. In addition to enormous isotopic heterogeneity (spanning from –25 to +1 per mil δ13C), bulk sediments also span a wide range in oxidation capacity, from carbonate to organic carbon. These highly heterogeneous point- and regional-sources of carbon fluxes, isotopes and oxidiation states provide natural laboratories to study recycling efficiencies at subduction zones and the creation of diamonds, carbonated melts and other carbon heterogeneities in the mantle.

Lakes and wetlands are natural sources and have an important role for hydrological cycle. They are also affected by climate change and anthropogenic activities such as precipitation regime, diminishing water bodies, uncontrolled groundwater extraction, drainage and irrigation channels, agricultural activities and discharge of domestic and industrial waste. For this reasons monitoring the lake surface areas are very crucial. In this paper; the Seyfe Lake was selected as a case study. The study area is located at the southern part of the Seyfe basin with a catchment area of 1447 km2 in Central Anatolia. Seyfe Lake wetland is located in a closed basin. The lake area and its surroundings is a Ramsar site and have the status of Grade 1 Natural Site and Protected Natural Area. This study aimed to evaluate the spatio-temporal changes of the surface area of Seyfe Lake by using Geographical Information Systems (GIS) and remote sensing techniques. For this purpose Landsat (MSS, TM, ETM+, OLİ/TIRS) satellite images used for a period between 1987 and 2020. A total of 34 images were processed and, using unsupervised classification method, water body was extracted according to the spectral information of the image bands and the historical change of the lake surface area was calculated by using Image Analysis Function of ArcGIS 10.6.1 software. In addition to these satellite images, long-term hydrometeorological data and field observations were analyzed to determine the changes of the Seyfe Lake surface area and understand the effects of climate change and antropojenic activities. According to the old and recent satellite images of Seyfe Lake area, the persisting shrinkage of lake area and diminishing of the water resources over the years in the Seyfe Lake basin still continue. Maximum and minumum surface area of the lake was calculated 43 km2 and 18 km2 respectively during 1987-2020. In August 2008; the lake area is completely dried. Nowadays the 58% of the lake area is dried up. These variations could probably be related with the antropogenic effects and climatic changes in the study area. As a result, Satellite based techniques might provide a historical data to identify changes on the lake surface area. Remote sensing techniques are also effective to evaluate temporal and spatial changes on water resources resulted by human activities and local climate change. In-situ observation and hydrogeological monitoring are another important tools to support findings of remote sensing study. Keywords: Spatio-temporal change, Wetland, Seyfe Lake, Unsupervised Classification, Remote Sensing

Volatile organic compounds (VOCs) play a crucial role in influencing the air quality of the urban atmospheres, especially in nitrogen oxide (NOx) dominated regions like India. Additionally, the associated direct health risks necessitate the identification of VOC sources and their contribution to the VOC budget of a region. This study presents the seasonal variability of VOCs measured using a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-QMS) during the year 2019 over the metropolitan Pune region. Also, the VOC sources have been identified using the US EPA PMF 5.0 model for different seasons. Toluene (summer: 2 μg/mΛ3, monsoon: 1.11 μg/mΛ3, winter: 7 μg/mΛ3), o-Xylene (summer: 1.41 μg/mΛ3, monsoon: 1.24 μg/mΛ3, winter: 5.67 μg/mΛ3), Acetaldehyde (summer: 2.80 μg/mΛ3, monsoon: 1.84 μg/mΛ3;, winter: 5.10 μg/mΛ3) and Acetone (summer: 5.95 μg/mΛ3, monsoon: 2.58 μg/mΛ3, winter: 6.21 μg/mΛ3) were found to be the prominent anthropogenic source-based emissions apart from Methanol (summer: 8.68 μg/mΛ3, monsoon: 5.24 μg/mΛ3, winter: 7.72 μg/mΛ3) which mostly has a biogenic source. While most of the identified sources (vehicular emissions, biomass burning, biogenic emissions, photochemical secondary products) are common throughout the year, their contribution to the total measured VOCs across seasons has varied considerably (9-17%, 8-12%, 5-14%, 19-27% respectively). Of the resolved factors, ozone formation potential (OFP) was found to be highest for photochemical secondary products (26%) during all the seasons, followed by vehicular emissions (23%) and background emissions (17%). The sources identified in this work are in agreement with a recent bottom to top emission inventory developed for the region which shows vehicular emissions as a dominant VOC source. This work highlights the role of meteorology in varying the VOCs concentration over the Pune region and eventually the local air quality.

Lakes are valuable and sensitive freshwater reservoirs with ecosystems that are highly vulnerable to many external threats. Specifically, changes in lake surface area and water level fluctuations are important parameters to detect changes in lake ecosystems. These fluctuations and shrinkage levels of the lake area occur due to both climatic and anthropogenic factors. Some examples of such include but are not limited to changes in meteorological factors, land use, potable water supply, water withdrawal for agricultural irrigation, and plant product pattern factors play an important role in the sustainability of the lake region and the water resources in the basin. In this paper, Seyfe Lake was selected as the primary research area. Seyfe Lake is located 30 km northeast of Kırsehir; the lake and its surroundings are a protected Ramsar site. The lake consists of a closed basin and the average area of the lake covers 35 km2, the calculation of which was obtained by interpretation of Landsat images and lake bathymetric studies. The average water depth of the lake is 1.65 m, with an elevation of 1110 m above sea level. The lake is recharged by rainfall, surface runoff, and underground flow. The discharge of the lake occurs via evaporation from the lake surface. The paper aims to evaluate the relationship between climatic and anthropogenic factors that caused the shrinkage of the Seyfe Lake surface area and water level changes in the lake to subsequently determine which factor predominantly posed a greater impact over three decades (1985-2020). Geological, hydrogeological, hydrological, and remote sensing surveys were carried out in the lake area and the basin. Furthermore, satellite images, meteorological data, lake bathymetric, and land cover maps were evaluated. It was determined that the lake surface area decreased from 66.87 km2 to 1.86 km2 and the lake area shrank by 93.78% between the years 1985 to 2020. In the period between 1990-2000, the total area of the lake was mainly controlled by climatic variations (precipitation and temperature). However, since the 2000s, there has been an increase in meteorological factors such as temperature and evaporation and contrastingly, a decrease in the amount of precipitation. When the land cover maps of the study area were evaluated, it was determined that rain-fed agriculture shifted to irrigated agriculture since 2006 within the lake basin. Additionally, it was concluded that the farmlands area increased and the transition to irrigated agriculture led to an increase in the amount of water used in agricultural irrigation with uncontrolled groundwater withdrawal from the wells in the lake basin. As a result of the research carried out in the study area, it was concluded that climatic and anthropogenic factors caused the decrease in the lake surface area and human activities impacted a greater share in the lake level change and shrinkage in the surface area in the last 15 years