Extraction of fluid resources from rock layers disturbs its initial hydrostatic equilibrium and results in rock layers dewatering. When fluid resources extraction finishes, the water head in dewatered aquifer recovers its original hydrostatic equilibrium. Afterwards, dewatered aquifer is subject to the phenomenon of decompaction. Finally, land uplift is observed on the surface. In spite of insignificant values of these movements, they may pose a severe threat. Land uplift implies the occurrence of a field of tensile stresses, which is particularly unfavourable for underground and surface infrastructure. In addition, increased flow of groundwater may cause the occurrence of mechanical scouring. Consequently, this phenomenon may result in sinkhole formation, particularly when rock layers are weakened by previously conducted mining workings.
The aim of presented research was to determine spatial and temporal distribution and dynamics of land uplift, which is associated with aquifer decompaction due to groundwater rebound. They were carried out in the area of one of the abandoned copper and anhydrite mines in Poland, in the period 2015-2018. In order to determine the values of land uplift, satellite data from Sentinel 1 mission were used. PS and SBAS methods were applied to data processing. Thus, substantial parts of study area were covered by observation points, including areas with medium and high vegetation index. In addition, due to the short data acquisition interval and a significant number of available satellite images, final maps of land uplift were generated in quarterly intervals. In the further part of the research, an analysis of the dynamics of observed land uplift regarding hydrogeological conditions was carried out. Furthermore, through a comparative analysis of land uplift and water heads, it was possible to determine the time factor. This parameter demonstrates the time-lag between the beginning of the process of aquifer decompaction and linked land uplift occurrence on the surface. Finally, obtained results were successfully compared with field data. Overall, presented research indicates the land uplift occurs within about 6 months from groundwater rebound, reaching up to ca. 8 mm per year. What is more, not only observed fields of tensile stresses occur in agricultural areas, but also they cover build-up areas related to several villages. Additionally, it should be pointed out, there are a few areas where land uplift occurs, however these movements are not spatially correlated to drainage center. The reason of this phenomenon could be the existence of unrecognized hydrogeological windows within the rock layers. They may disturb the expected spatial distribution of land uplift.
To conclude, the carried out research proved the use of satellite data of short and repeatable acquisition intervals in conjunction with advanced data processing methods enable conduction of reliable quasi-continuous monitoring of land uplift. Moreover, much more effective cause-and-effect inference describing given processes was carried out. Thus, the presented research contributes to a better understanding of ground movements associated with aquifer decompaction. This is even more important, the fewer opportunities of monitoring the hydrostatic balance recovery process in the areas where fluid mineral resources are extracted from rock layers.

Area A - Board 77

The Sentinel-4 (S4) mission, the first imaging spectrometer instrument to be flown on Meteosat Third Generation Sounding (MTG-S) satellite in geostationary orbit, will provide accurate data on an hourly basis of trace gases and aerosols over Europe and Northern Africa for climate, air quality, ozone and surface UV applications. It features bands in the ultraviolet (305-400 nm), and visible (400-500 nm) with a spectral resolution of 0.5 nm and in the near-infrared (750-775 nm) ranges with a spectral resolution of 0.12 nm.

To provide simulated S4-UVN instrument data, we are working to prepare the Instrument Data Simulator (IDS). IDS is supposed to provide test data for the L1b Processor and provide capability for instrument performance and calibration monitoring. The IDS consists of two main blocks: the Scene Generator (SG) simulates the radiance/irradiance at the entrance of the instrument and the Instrument Simulator (IS) simulates the response of the instrument on the input signal. The S4-UVN IS follows as much as possible the instrument forward model and will be developed using a ’travelling spectrum’ approach. In this approach, the flux in the instrument or signal and noise is modified step-by-step by a series of algorithms representing the effects of the different components of the instrument on signal when flowing through the instrument. The ‘spectrum’ is a matrix of pixel or sample contents with associated matrix of wavelengths and swath direction viewing angles and, as needed, an associated vector of times or flight direction viewing angles. The flow starts with scene data generated from SG and continues algorithms describing the various effects encountered in the telescope (with scrambler), the spectrometers, the detectors and the electronics. Along with the signal, the noise associated to the signal is also
propaagted throguh the instrument.

In this presentation, the IDS architecture and instrument forward model will be introduced.

Area D - Board 357

NO2 and HCHO are important trace gases for life on Earth because they are hazardous to human health. As they originate mostly from anthropogenic as well as biogenic sources, continuous measurements are able to reveal man-made trends which might affect the climate and life on Earth. In order to assess the spatial distribution of these trace gases on a global scale, long-term satellite measurements are needed.
For this purpose, EUMETSAT's satellites MetOp-A and B provide a continuous dataset created by similar instruments since 2006 which will be extended and enhanced by data from the recently launched Metop-C satellite.

Here, we present first scientific results of the GOME2 instrument on board of EUMETSAT's MetOp-C satellite retrieved with the frequently used differential optical absorption spectroscopy (DOAS). Since all three GOME2 instruments on board of the MetOp satellites measure simultaneously, a direct comparison of results enables the quantification of instrumental characteristics and possible issues which may be corrected in improved versions of the lv1 data.

The focus of this poster is on the comparison of slant and vertical column densities from the three GOME2 instruments in orbit. GOME2 data from MetOp-C will be analysed for the signal to noise ratio, the consistency with measurements from the other GOME2 instruments, and for possible problems in the calibration of the lv1 data. The latter will be addressed by investigation of slant column dependencies on viewing geometry and observation conditions and also by analysis of fitting residuals as was already successfully done for the previous GOME2 instruments. In order to investigate possible degradation effects, the analysis will be performed with using data taken simultaneously but also with observations from comparable early lifetime conditions of GOME2-A and B.

On this poster, results from our instrumental comparison tests will be presented, uncertainties discussed and a first assessment of the potential data quality of GOME2-C will be given.

Area D - Board 358