European Space Agency Earth Observation Research Articles

The Application of Sentinel-2 Data for Automatic Forest Cover Changes Assessment – Białowieża Primeval Forest Case Study

Sentinel-2 mission, as a part of European Space Agency Earth Observation Program Copernicus, designed specifically for Earth surface observations provides images in 13 bands. That imaging is used to analyse many subject areas as Land monitoring, Emergency management, Security and Climate change. In the presented paper the application of Sentinel-2 data for automatic forest cover changes detection has been analysed. As input data, B02, B03, B04 and B08 bands have been used to compute Normalized Difference Vegetation Index (NDVI) and Enhanced Normalized Difference Vegetation Index (ENDVI). To track changes in the forest cover over the years, for each pixel the difference in the value of vegetation indices between consecutive years have been calculated. Then the threshold was set at the level of 0.15. The values of differences above the threshold mean a significant decrease in the quality of vegetation and may be considered areas of deforestation.

An Introduction to the HydroGNSS GNSS Reflectometry Remote Sensing Mission

HydroGNSS (Hydrology using Global Navigation Satellite System reflections) has been selected as the second European Space Agency (ESA) Scout earth observation mission to demonstrate the capability of small satellites to deliver science. This article summarizes the case for HydroGNSS as developed during its system consolidation study. HydroGNSS is a high-value dual small satellite mission, which will prove new concepts and offer timely climate observations that supplement and complement the existing observations and are high in ESAs earth observation scientific priorities. The mission delivers the observations of four hydrological essential climate variables as defined by the global climate observing system using the new technique of GNSS reflectometry. These will cover the world's land mass to 25 km resolution, with a 15-day revisit. The variables are soil moisture, inundation or wetlands, freeze/thaw state, and above-ground biomass.

Spatial and temporal variation of bulk snow properties in northern boreal and tundra environments based on extensive field measurements

Abstract. An extensive in situ data set of snow depth, snow water equivalent (SWE), and snow density collected in support of the European Space Agency (ESA) SnowSAR-2 airborne campaigns in northern Finland during the winter of 2011–2012 is presented (ESA Earth Observation Campaigns data 2000–2016). The suitability of the in situ measurement protocol to provide an accurate reference for the simultaneous airborne SAR (synthetic aperture radar) data products over different land cover types was analysed in the context of spatial scale, sample spacing, and uncertainty. The analysis was executed by applying autocorrelation analysis and root mean square difference (RMSD) error estimations. The results showed overall higher variability for all the three bulk snow parameters over tundra, open bogs and lakes (due to wind processes); however, snow depth tended to vary over shorter distances in forests (due to snow–vegetation interactions). Sample spacing/sample size had a statistically significant effect on the mean snow depth over all land cover types. Analysis executed for 50, 100, and 200 m transects revealed that in most cases less than five samples were adequate to describe the snow depth mean with RMSD < 5 %, but for land cover with high overall variability an indication of increased sample size of 1.5–3 times larger was gained depending on the scale and the desired maximum RMSD. Errors for most of the land cover types reached ∼ 10 % if only three measurements were considered. The collected measurements, which are available via the ESA website upon registration, compose an exceptionally large manually collected snow data set in Scandinavian taiga and tundra environments. This information represents a valuable contribution to the snow research community and can be applied to various snow studies.

European ice satellite replacement approved

The European Space Agency (ESA) will build and launch a new CryoSat spacecraft to study polar and sea ice, the agency announced on 24 February. The first CryoSat was lost on 8 October 2005 when the rocket and spacecraft fell into the ocean north of Greenland due to problems with the rocket launcher.At a 23–24 February meeting of the ESA's Earth Observation Programme Board, the agency received permission from its member states for CryoSat‐2, which will have the same mission objectives as the satellite it replaces.

Establishing A Earth Observation Product Service For The Terrestrial Carbon Community: The Globcarbon Initiative

'Greenhouse gases', especially carbon dioxide, are intimately connected to climate change. To understand the future evolution of the climate system and find ways to manage the concentration of atmospheric carbon dioxide, the processes and feedbacks that drive the carbon cycle must first be understood. However, our current knowledge of spatial and temporal patterns is uncertain, particularly over land and in regions of potentially high sensitivity to change like the boreal zone. The European Space Agency (ESA) GLOBCARBON project aims to generate fully calibrated estimates of at-land products quasi-independent of the original Earth Observation source for use primarily in Dynamic Global Vegetation Models, but also as a contribution to the Global Carbon Project, a cooperation between the International Geosphere Biosphere Programme, International Human Dimensions Programme and the World Climate Research Programme to aid understanding of global carbon cycling. The service will feature estimation of global burned area, the fraction of absorbed photosynthetically active radiation (fAPAR), leaf area index (LAI) and Vegetation Growth Cycle. The demonstrator will focus on ten complete years, from 1998 to 2007 when overlap exists between ESA Earth Observation sensors and others that are synergistic. However, the system will be flexible so that it is not dependent on any single satellite sensor and therefore can be retrospectively applied to existing archives and used with future satellite sensors.

Performance of sea surface salinity and soil moisture retrieval algorithms with different auxiliary datasets in 2-D L-band aperture synthesis interferometric radiometers

The Soil Moisture and Ocean Salinity (SMOS) Earth Explorer Opportunity Mission was selected in May 1999 by the European Space Agency Earth Observation Programme Board to provide global and frequent soil moisture (SM) and sea surface salinity (SSS) maps. SMOS' single payload is the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS) sensor, an L-band two-dimensional aperture synthesis interferometric radiometer with multiangular and polarimetric imaging capabilities. The definition of the SMOS Level 2 Processor requires the selection of the optimum operation mode (dual-polarization or full-polarimetric) for each application, the specification of the required auxiliary data, and the optimum retrieval algorithms. Using the SMOS simulator and based on the experience gained in previous works, this paper presents a study of the SM and SSS retrieval capabilities over homogeneous pixels, in the two modes of operation with different auxiliary data. It is found that SSS retrievals using the first Stokes parameter measured in the dual-polarization mode perform somewhat worse than using the vertical (T/sub vv/) and horizontal (T/sub hh/) brightness temperatures measured in the full-polarimetric mode, and the performance degrades for cold waters due to the lower sensitivity of the brightness temperature to SSS at low sea surface temperature (SST). Due to the larger angular variation of T/sub hh/ and T/sub vv/, SM retrievals using T/sub hh/ and T/sub vv/ measured in the full-polarimetric mode exhibit a significant better performance over bare soils than over vegetation-covered soils. Over vegetation-covered soils vegetation parameters (opacity and albedo) can be inferred over a 550-km swath width in the full-polarimetric mode. However, since the first Stokes parameter is independent of both geometric and Faraday rotations, it is very robust in the presence of instrumental and geophysical errors. In the SSS retrieval problem and in the SM retrieval problem (with T/sub hh/ and T/sub vv/ measured in the full-polarimetric mode), the performance of the retrieval algorithms tested is not significantly altered if the model parameters are not exactly known, but are left as adjustable parameters in the optimization process.

Europe Forges a Plan in Collaboration With Industry

[ Helen Gavaghan ][1] Last month, a European Space Agency (ESA) task force outlined a new strategy for supporting Earth-observation missions that would make industry a full partner in designing, developing, and funding an entire class of missions. The proposal, previewed at a crowded meeting of industrialists at ESA's science and technology center in Noordwijk, the Netherlands, on 18 December, would divide future Earth-observation programs into two types: scientific mission, which would be fully paid for out of ESA's budget, and applications missions, which would be private initiatives or risk- and cost-sharing partnerships between the agency and industry, which ESA would join only if the industrial sponsors already have purchasers for their data lined up. This new plan, which will be fleshed out at ESA headquarters over the next few months and presented to the organization's member states this summer, is designed to fill a looming gap in ESA's Earth-observation program. [1]: http://www.sciencemag.org#name