Geoinformation Issues Vol. 8, No 1, 2016
Editorial pages, contents, reviewers of journal "Geoinformation Issues"
editorial pages, contents, reviewers of journal to download
Marcin Sękowski, Przemysław Dykowski, Jan Krynski
A new superconducting gravimeter station in Central Europe: the iGrav-027 at the Borowa Gora Geodetic-Geophysical Observatory – installation and first results
DOI: 10.34867/gi.2016.1
Abstract: The gravimetric infrastructure of the Borowa Gora Geodetic-Geophysical Observatory of the Institute of Geodesy and Cartography, Warsaw, Poland, equipped so far with four LaCoste&Romberg model G gravimeters (3 of them with modern feedback systems) and the A10-020 field absolute gravimeter was enhanced in 2016 with a new iGrav-027 superconducting gravimeter. The iGrav-027 field gravimeter was delivered to the Observatory at the beginning of February 2016 and became fully operational late April 2016.
The paper describes major aspects of the installation of the instrument as well as some technical issues faced during its installation. It also presents results of the initial analysis of data collected during the first month of operation of the instrument. The iGrav-027 records have been compared with 2.5 day simultaneous records of the A10-020 gravimeter, as well as with data obtained from three LaCoste&Romberg gravimeters which are used at the Borowa Gora Observatory for acquiring tidal records. Initial analysis also includes the first attempt to determine the scale factor (part of the transfer function) for the iGrav-027 superconducting gravimeter.
Elżbieta Welker, Jan Reda
Magnetic measurements, apparatus and metrology
DOI: 10.34867/gi.2016.2
Abstract: The magnetic field of the Earth is changing over time. Different kinds of changes – long-term (secular changes), daily changes and short-term changes – can be distinguished. The amplitude and character of these changes depend on the geomagnetic coordinates of the measurement point and current geomagnetic activity. Recently, instruments used for absolute geomagnetic measurements (magnetometer DI-fluxgate and proton magnetometer) have guaranteed high precision even at the level of 1 nT but the measurements of the geomagnetic field elements are not repeatable. Checking and testing the instruments for geomagnetic measurements must be performed only in a geomagnetic observatory which holds trusted apparatus that participated in the relevant international comparison campaigns organized by the International Association of Geomagnetism and Aeronomy (IAGA). After processing the results of the comparison campaign, the corrections for each instrument – for three elements of the geomagnetic field – are determined.
Katarzyna Dąbrowska-Zielińska, Maciej Bartold, Radosław Gurdak
POLWET – system for new space-based products for wetlands under Ramsar Convention
DOI: 10.34867/gi.2016.3
Abstract: The main objective of the POLWET project is to establish wetlands monitoring system and to create the dedicated EO-based information service as a platform enabling on-line accessibility of the final products to the end-users. The service will be useful for appropriate sustainable wetlands management and conservation, by offering the products such as: land use/land use changes, changes of water surface, floods extent, moisture conditions, biomass development and changes.
Within the POLWET project various EO-based products will be generated for the selected wetland areas in Poland included to Ramsar Convention. High and low resolution optical satellite data derived from Landsat mission (1984–2015) and Terra.MODIS (2001–2015) will be applied. Radar images derived from Envisat.ASAR (2003–2011) will be exploited as well. The satellite observations derived from Sentinel mission (2015–2016) will be used to elaborate the latest maps. Data collected by the satellites characterize diversified spatial, temporal and radiometric resolution. The satellite observations allow to elaborate comprehensive information service, performed at a local as well as global level.
For each of thirteen Ramsar Convention protected areas in Poland, series of maps presenting vegetation indices and surface temperature will be produced on the basis of satellite observations. The maps of vegetation indices enable spatiotemporal analysis of vegetation condition and support on monitoring of environmental hazards. The maps of surface roughness and soil moisture will be elaborated on the basis of archival and actual Sentinel-1 radar images. The relationship between backscatter ?0 and vegetation parameters will be established for each of the wetland land cover class. The canopy height model will be developed from radar images as well.
Within the research the methodology on change detection using Landsat time-series covering period 1987–2014 was developed. The results on land cover changes over Narew valley were firstly verified analyzing the maps derived from Narew National Park headquarters. Next the results on changes were validated using the numerical data derived from the CORINE Land Cover database. The accuracy of properly detected changes over Narew National Park has been achieved at 86.3%.
The project POLWET, funded by European Space Agency ESA is in the stream of researches where multitemporal and high-resolution satellite data Landsat and Sentinel are exploited in order to monitor global land cover changes. The information system built within the project of Ramsar wetland sites in Poland, will support future GlobWetland III project, which is international initiative aimed to build information service for two hundred wetland areas covered in the Mediterranean Basin.
Jan Musiał, Katarzyna Dąbrowska-Zielińska, Wojciech Kiryła, Ryszard Oleszczuk, Tomasz Gnatowski, Jacek Jaszczyński
Derivation and validation of the high resolution satellite soil moisture products: a case study of the Biebrza Sentinel-1 validation sites
DOI: 10.34867/gi.2016.4
Abstract: Soil moisture content is a key variable for numerous disciplines hence the need for its constant monitoring at a global scale. Satellite imagery is the only mean to fulfil this objective. New generations of satellite sensors such as the Sentinel-1 SAR (Synthetic Aperture Radar) system provide measurements at fine spatial and temporal scales. In order to validate such estimates dense in-situ networks measuring soil moisture are required. The scarcity of such networks was the main motivation to establish two validation sites
over the Biebrza wetlands within the project funded by the ESA (European Space Agency). The sites are covered by grassland and marshland and are internally homogeneous as far as the soil type and vegetation cover are concerned. Each site is equipped with 9 soil moisture monitoring stations installed every 130 m which allows the derivation of reliable mean soil moisture estimates across the site featuring small standard deviation (0.035 m3/m3 for the grassland site and 0.074 m3/m3 for the marshland site). The main objective of
the presented study is to review the soil moisture derivation and validation methodologies suitable for the Sentinel-1 SAR satellite data and to describe physiographical settings of the Biebrza validation sites together with the installed instrumentation. Furthermore, the relationship between the time series of soil moisture measurements and Sentinel-1 sigma nought backscatter coefficient (?0) is examined. Ultimately, the validation results of the low resolution SM-DAS-2 soil moisture product are presented due to the unavailability of the high resolution product.
Katarzyna Dąbrowska-Zielińska, Piotr Goliński, Marit Jørgensen, Jørgen Mølmann, Gregory Taff, Stanisław Twardy, Maria Budzyńska, Marek Czerwiński, Marek Kopacz, Robert Kurnicki, Wanda Kowalik, Monika Tomaszewska, Alicja Malińska, Barbara Golińska, Martyna Gatkowska
Importance of grassland monitoring in European perspective of climate change – FINEGRASS project
DOI: 10.34867/gi.2016.5
Abstract: The objective of the study was an assessment of the effect of climatic changes on grassland growth, its water conditions and biomass. Forecasting the grassland biomass and indicating the influence of climate on grasslands growth could be an important tool in grassland management on the national, regional and field grassland scales. Remote sensing gives the possibility to estimate the grassland growth conditions what have been achieved applying NOAA.AVHRR and Terra.MODIS. Identification of grasslands throughout the country have been done using Corine Land Cover (CLC) database. Vegetation index (NDVI) and surface temperature (Ts) have been calculated from satellite data. Meteorological data for Poland have been collected: i) for years 1997–2015, ii) for the period 1985–2014 to find the trends of climatic changes. There have been found: significant trends in air temperature (Ta) in NUTS1 in Poland; significant trend of increasing
grassland surface temperature (Ts) in Poland based on satellite data; comparable results between Ts – Ts_mean and Ta – Ta_mean for the years 1997–2015; significant positive relationship between the (April-September) standardized precipitation evapotranspiration index (SPEI) and grass yields in Poland. In Norway, a trend towards earlier growth start in spring and increasing temperature sum in the growing season for the last ten years have been found, however, with large variation between years. Also, trends towards warmer springs and autumns since 1991 in Northern Norway has been observed. Climate changes may affect positively and negatively the grassland productivity. Proposed new and efficient methods based on satellite observations, can be used to monitor the productivity of grasslands to understand trends and anomalies that are likely to continue into the future, can help in planning for agricultural practices, can be an efficient tool in decision support system of grassland management and offsetting financial risks on large scales.