Some recent advances in remote sensing-based monitoring of changes in the Greenland Ice Sheet

The mass balance of the Greenland Ice Sheet(GrIS)plays a crucial role in global sea level change.Since the 1960s,remote sensing missions have been providing extensive and continuous observation data for change monitoring of the GrIS.In this paper,we present our recent research results from remote sensing-based GrIS change monitoring.First,historical satellite data are processed and used to fill data gaps and are combined with existing partial maps,completing an ice velocity map of the GrIS from the 1960s to 1980s.This map provides valuable data for estimating the historical mass balance of Greenland.Second,the monthly gravimetry-based mass balance of the GrIS from 2002 to 2020 is estimated by combining Gravity Recovery and Climate Experiment(GRACE)and GRACE Follow On(GRACE-FO)data.It is found that the GrIS has lost a total mass of approximately 4443±75 Gt during this period.Third,based on Global Land Ice Measurements from Space(GLIMS),an updated Greenland glacier inventory is achieved utilizing data collected between 2006 and 2020.This inventory provides more detailed and up-to-data glacier boundaries of Greenland.Overall,these advances provide essential data support for estimating the mass balance of the GrIS,contributing to the advancement of research on global sea level change.

Monitoring the change in horizontal stress with multi-wave time-lapse seismic response based on nonlinear elasticity theory

Monitoring the change in horizontal stress from the geophysical data is a tough challenge, and it has a crucial impact on broad practical scenarios which involve reservoir exploration and development, carbon dioxide (CO_(2)) injection and storage, shallow surface prospecting and deep-earth structure description. The change in in-situ stress induced by hydrocarbon production and localized tectonic movements causes the changes in rock mechanic properties (e.g. wave velocities, density and anisotropy) and further causes the changes in seismic amplitudes, phases and travel times. In this study, the nonlinear elasticity theory that regards the rock skeleton (solid phase) and pore fluid as an effective whole is used to characterize the effect of horizontal principal stress on rock overall elastic properties and the stress-dependent anisotropy parameters are therefore formulated. Then the approximate P-wave, SV-wave and SH-wave angle-dependent reflection coefficient equations for the horizontal-stress-induced anisotropic media are proposed. It is shown that, on the different reflectors, the stress-induced relative changes in reflectivities (i.e., relative difference) of elastic parameters (i.e., P- and S-wave velocities and density) are much less than the changes in contrasts of anisotropy parameters. Therefore, the effects of stress change on the reflectivities of three elastic parameters are reasonably neglected to further propose an AVO inversion approach incorporating P-, SH- and SV-wave information to estimate the change in horizontal principal stress from the corresponding time-lapse seismic data. Compared with the existing methods, our method eliminates the need for man-made rock-physical or fitting parameters, providing more stable predictive power. 1D test illustrates that the estimated result from time-lapse P-wave reflection data shows the most reasonable agreement with the real model, while the estimated result from SH-wave reflection data shows the largest bias. 2D test illustrates the feasibility of the proposed inversion method for estimating the change in horizontal stress from P-wave time-lapse seismic data.

Monitoring open water area changes in a small tarn using historical orthophotomaps and a historical bathymetric map:a case study of the Litworowy Staw lake,the High Tatras

According to scientific evidence in general, the disappearance of the Tatras tarns as a result of external geomorphological processes has been accepted since the long term analyses of lake sediments and peat bogs, geomorphological mapping, geophysical measurements(– all indirect methods). It is paradoxical that the direct cartographic evidence of such changes has not existed until now. In this paper, we evaluate shore line changes of the small mountain glacial lake in the High Tatras-Litworowy Staw lake using a multitemporal analysis of a series of historical orthophotomaps and a historical map. Over the last 100 years, the tarn has lost 46.4% of open water level area. Significant visual changes were caused by vegetation growth of Carex species(sedges) on the water's surface. The accumulation of fine sediments and dead plant residues in the tarn basin create suitable conditions for this process, all together causing the tarn to become more shallow.

Monitoring the changes in plasm C-reactive protein,fibrinogen and blood white cell in patients with primary hypertension combined with acute cerebral infarction

BACKGROUND： Inflammatory reaction and the increased level of its accompanying active protein play an important role in the occurrence and development of cerebral infarction. C-reactive protein, fibrinogen and white blood cell, as the monitoring index of inflammatory reaction, are very important in the occurrence and development of acute cerebral infarction. OBJECTIVE： To make a comparison between patients with primary hypertension accompanied with acute cerebral infarction and with simple primary hypertension by observing the changes in plasma C-reactive protein and fibrinogen levels as well as white blood cell and differential counts and analyzing their significances. DESIGN ： Controlled observation SETTING ： Ward Building for VIP, Shenzhen Hospital, Peking University. PARTICIPANTS： Totally 133 patients with primary hypertension were selected from Ward Building for VIP, Shenzhen Hospital, Peking University during September 2003 to September 2005, The diagnostic criteria were based on the hypertension diagnosis criteria formulated by the 7^th World Health Organization-International Society of Hypertension Guidelines （WHO-ISH） in 1998. The informed consents were obtained from all the participants. The involved patients were assigned into two groups： primary hypertension group, in which, there were 65 patients with primary hypertension （ degree 2）, including 42 males and 23 females, with mean age of （61 ±14）years and mean blood pressure of （162.7±6.8）/（94.2±8.4） mm Hg （1 mm Hg =0.133 kPa）, and primary hypertension combined with cerebral infarction group, in which, there were 68 patients with primary hypertension combined with cerebral infarction （ meeting the diagnostic criteria formulated in the 4^th National Cerebrovascular Diseases Meeting in 1995 and diagnosed by skull CT or MRI to exclude the patients with lacunar infarction）, including 42 males and 26 females, with mean age of （56±15） years and mean blood pressure of （176.4±9.2）/（96.3±9.7） mm Hg. METHODS： Plasm C-reactive protein and fibrinogen levels, and white blood cell and differential counts of patients in the two groups were examined 24 hours after stroke. The above indexes were re-examined in the primary hypertension combined with cerebral infarction group 72 hours after stroke. White blood cell and differential counts were performed with laser method （East Asia FE-95001 RAM-1, Japan）. The level of C-reactive protein was measured with turbidimetry （BNII Automatic Systems For Analysis, USA）. The level of fibrinogen was measured with algorithm method when prothrombin time was normal and with Clauss method when prothrombin time was abnormal （ACL Automatic Coagulation Analyzer, USA）. MAIN OUTCOME MEASURES： The plasm C-reactive protein and flbrinogen levels, and white blood cell and differential counts 24 hours after stroke in two groups and 72 hours after stroke in primary hypertension combined with cerebral infarction group. RESULTS： All the 133 involved patients participated in the result analysis. The plasm C-reactive protein and fibrinogen levels, and white blood cell and neutrophil counts in patients with primary hypertension were all within the normal range. The plasm C-reactive protein and fibrinogen levels, and white blood cell and neu- trophil counts in patients with primary hypertension combined with cerebral infarction were significantly higher than those in patients with primary hypertension 24 hours after stroke and 72 hours after stroke respectively[24 hours after stroke：（32.12±11.76） mg/L vs. （5.02±3.21 ） mg/L;（4.64±0.75） g/L vs. （3.12±0.49） g/L; （9.32±81）×10^9 L^- 1 vs. （5.78±1.32）×10^9L^- 1 （7.85±2.38）×10^9 L^- 1 vs.（3.49±1.28）×10^9 L^-1,t =7.094, 5.759,4.106,5.491, respectively,all P〈 0.01; 72 hours after stroke： （47.62±18.43） mg/L vs. （32.12±11.76） mg/L; （5.08±0.82） g/L vs. （4.64±0.75） g/L, t =2.864,2.220, respectively, both P 〈 0.05]. CONCLUSION： The increase in fibrinogen level and white blood cell count are the important index in monitoring primary hypertension combined with acute cerebral infarction. The increase in plasm C-reactive protein and fibrinogen levels 72 hours after stroke indicates that plasma C-reactive protein and fibrinogen are very important in the development of disease.

Monitoring Land Use and Infrastructure Changes in Industrial Complex Using Geo-Informatics Technology in Gujarat State, India

In the present study, detailed investigations have been carried out in Petroleum, Chemicals and Petrochemical Investment Region (PCPIR) area in Vygra and Bharuch Talukas in Bharuch district of Gujarat State. Indian Remote Sensing Satellite (IRS-P6) LISS-III, LISS-IV and CARTOSAT digital data covering PCPIR area in Bharuch district for the period of January & February of 2011, 2012 and 2013 was analyzed for land use/land cover mapping and monitoring the changes in land use. Various thematic land use/land cover maps were prepared and GIS database for various thematic layers have been generated using satellite and ground based information. The results indicate that the major land use in the PCPIR area is agriculture with crop lands ranging from 61 to 63 per cent of the total area. Crop land has decreased from 64.7% during 2011 to 62.7% during 2013 in the PCPIR region. Area under plantations in PCPIR area has also decreased from 5.5% during 2011 to 5.2% during 2012. The industrial area has increased from 6.0% to 7.6% of the total area of the PCPIR region. The total built-up area (industries & village area) has increased from 7.1% during 2011 to 8.7% during 2013. Tree plantations in the area of around 42 ha were carried out by GIDC during 2012 and 2013 to increase the green cover in the PCPIR area.

The Macrolichens of Barluk Mountain National Nature Reserve, Xinjiang Province, China

A checklist of the macrolichens (foliose, fruticose & squamulose) of Barluk Mountain National Nature Reserve located in northwestern China is presented. It was derived from 47 inventories of preserved and undeveloped areas which yielded more than 670 collections containing 102 taxa (99 species, 1 subspecies, 2 varieties). Eight species were found that were new to Xinjiang, China. Twenty-eight species and 2 varieties were found on rock, 31 species on bark of deciduous and coniferous trees, 26 species on soil and 14 species and 1 subspecies over mosses. Foliose lichens were dominant with 76 species, followed by 16 species of squamulose lichens and 7 species of fruticose lichens.

On the application of DInSAR to deformation monitoring in desert areas

The DInSAR technique is used for monitoring the desert height changes to study sandstorms. Hunshandake Sandy Land, as the test area, is one of the main sources of sandstorms in Beijing. In order to study the sandstorm source and its impact, a pair of EnviSat ASAR images of Oct. 11, 2005, and Oct. 26, 2004, is processed on the basis of analysis of six ERS-2 and EnviSat radar images. After the image configuration, flat earth effect correction, data filtering, phase unwrapping, and geo-coding, a deformation model over Hunshandake desert is built. According to the results, the height decreased in most areas and increased in a few areas, which basically coincides with the strong sandstorm appearing in Beijing in the Spring of 2005. The results show DInSAR has an important role in monitoring of desert surface deformation.

Field testing innovative differential geospatial and photogrammetric monitoring technologiesin mountainous terrain near Ashcroft,British Columbia,Canada

This paper presents a novel approach to continuously monitor very slow-moving translational landslides in mountainous terrain using conventional and experimental differential global navigation satellite system(d-GNSS)technologies.A key research question addressed is whether displacement trends captured by a radio-frequency“mobile”d-GNSS network compare with the spatial and temporal patterns in activity indicated by satellite interferometric synthetic aperture radar(InSAR)and unmanned aerial vehicle(UAV)photogrammetry.Field testing undertaken at Ripley Landslide,near Ashcroft in south-central British Columbia,Canada,demonstrates the applicability of new geospatial technologies to monitoring ground control points(GCPs)and railway infrastructure on a landslide with small and slow annual displacements(<10 cm/yr).Each technique records increased landslide activity and ground displacement in late winter and early spring.During this interval,river and groundwater levels are at their lowest levels,while ground saturation rapidly increases in response to the thawing of surficial earth materials,and the infiltration of snowmelt and runoff occurs by way of deep-penetrating tension cracks at the head scarp and across the main slide body.Research over the last decade provides vital information for government agencies,national railway companies,and other stakeholders to understand geohazard risk,predict landslide movement,improve the safety,security,and resilience of Canada’s transportation infrastructure;and reduce risks to the economy,environment,natural resources,and public safety.

Dynamic Changes of Land Use in Built-up Area of Chengde City in the Past 14 Years

Landsat TM/OLI images of the built-up areas in Chengde City(Shuangqiao District and Shuangluan District) in 2000,2009 and 2014 were adopted,Support Vector Machine(SVM) was applied to classify the images automatically,land use/cover map of the study area was obtained after precision test.Through analyzing the land use types in the study area and also applying transfer matrix to monitor the changes,the results showed that human activities and urbanization in the past 14 years have brought the increasing tendency of construction land,and the negative growth of arable land,forest and shrubbery land.It is urgent to adopt corresponding measures to maintain the coverage of forest and shrubbery land in the built-up area of Chengde City,so as to reduce the impact of human activities and improve urban ecological environment.

Risk Assessment and Change Monitoring of Soil and Water Loss in Ruijin City Based on RS and GIS

The land use information extraction technology for the high-resolution remote sensing images of the Gaofen No. 1 satellite was construc-ted. According to the spectral, band, texture and shape attributes, land use types were divided, and the changing laws of land use types were ana- lyzed. Aftewards,according to the Table of Grading Standard of Sooil Erosion Intensity（SL190-96）,as well as vegetation coverage index NDVI slope, the risks of soil and water loss were assessed. Meanwhile, the level, scale, location and scope of changes in the risks of soil and water loss were monitored by using spatial visualization and spatial statistical techniques. The results showed that the area of areas without soil erosion and moderate soil erosion areas decreased obviously from 2015 to 2017, and the decreases were up to 22.929 3 and 13.626 3 km2 respectively. The ar-ea of mild soil erosion areas increased fast, and the increase reached 31.140 0 km2. The area of extremely strong soil erosion areas increased by 7.267 4 km2. In the city, moderate and strong soil erosion areas reduced, while extremely strong soil erosion patches increased fast, which was mainly related to road construction and construction and development of orchards. The extremely strong soil erosion areas were distributed in the shape of a banded loop, surrounded the suburbs of the city, and shrank towards the center of Ruijin City. The constructed technology to monitor the changes in land use and soil and water loss, as well as the changing laws of land use and soil and water loss provide the theoretical basis and plan-ning basis of soil and water conservation for urban planning departments and soil and water conservation departments.

Goce derived geoid changes before the Pisagua 2014 earthquake

The analysis of space-time surface deformation during earthquakes reveals the variable state of stress that occurs at deep crustal levels, and this information can be used to better understand the seismic cycle. Understanding the possible mechanisms that produce earthquake precursors is a key issue for earthquake prediction. In the last years, modern geodesy can map the degree of seismic coupling during the interseismic period, as well as the coseismic and postseismic slip for great earthquakes along subduction zones. Earthquakes usually occur due to mass transfer and consequent gravity variations, where these changes have been monitored for intraplate earthquakes by means of terrestrial gravity measurements. When stresses and correspondent rupture areas are large, affecting hundreds of thousands of square kilometres（as occurs in some segments along plate interface zones）, satellite gravimetry data become relevant. This is due to the higher spatial resolution of this type of data when compared to terrestrial data, and also due to their homogeneous precision and availability across the whole Earth.Satellite gravity missions as GOCE can map the Earth gravity field with unprecedented precision and resolution. We mapped geoid changes from two GOCE satellite models obtained by the direct approach,which combines data from other gravity missions as GRACE and LAGEOS regarding their best characteristics. The results show that the geoid height diminished from a year to five months before the main seismic event in the region where maximum slip occurred after the Pisagua Mw = 8.2 great megathrust earthquake. This diminution is interpreted as accelerated inland-directed interseismic mass transfer before the earthquake, coinciding with the intermediate degree of seismic coupling reported in the region. We highlight the advantage of satellite data for modelling surficial deformation related to preseismic displacements. This deformation, combined to geodetical and seismological data, could be useful for delimiting and monitoring areas of higher seismic hazard potential.

Status and outlook of hiking trails in the central part of the Low Tatra Mountains in Slovakia between 1980–1981 and 2013–2014

This study presents a methodology for assessment of the condition of hiking trails(HTs) and their impact zones in the central part of the Low Tatra mountain range, based on comparison of two complex data sets gathered in 33 years apart. The first field investigation was performed in 1980 and 1981, and the second in 2013 and 2014. The main goal was to perform a landscape typology in order to assess the susceptibility of landscape complexes to occurrence of anthropogenic and natural destruction processes and to assess the condition and prospects of HTs and their impacts on the adjacent alpine environment. Landscape complexes were characterised by selected abiotic, biotic and technical parameters of HTs and their impact zones. Due to the high variability of these parameters over the length of the HTs, we had to decide on how to map them. This was done using a square grid with 100 m-sized cells. For each cell with HT, the parameters were assigned the typical value within that cell. In total, 26.3 km of HT were studied, stretching over 266 grid cells. On comparison of the two data sets, it was seen that, 64%(171 grid cells) display a generally positive condition, with 54%(143 grid cells) even exhibiting significant improvement or continuously positive state of their condition. 36%(95 grid cells) were in bad condition, including 3%(9 grid cells) whose state had deteriorated, and 2%(6 grid cells) whose state had significantly deteriorated, in the time between the two assessments.