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The interpretation of optical Earth observation data (remote sensing data from satellites) requires knowledge of the exact geographic position of each pixel as well as the exact local acquisition time. But these parameters are not available in each case. If a satellite has a sun-synchronous orbit, equator crossing time (ECT) can be used to determine the local crossing time (LCT) and its corresponding solar zenith distance. Relation between local equator crossing time (LECT) and LCT is given by orbit geometry. The calculation is based on ECT of satellite. The method of actual ECT determination for different satellites on basis of the two-line-elements (TLE), available for their full lifetime period and with help of orbit prediction package is well known. For land surface temperature (LST) studies mean solar conditions are commonly used in the relation between ECT given in Coordinated Universal Time (UTC) and LECT given in hours, thus neglecting the difference between mean and real Sun time (MST, RST). Its difference is described by the equation of time (ET). Of particular importance is the variation of LECT during the year within about ±15 minutes. This is in each case the variation of LECT of a satellite, including satellites with stable orbit as LANDSAT (L8 around 10:05 a.m.) or ENVISAT (around 10:00 a.m.). In case of NOAA satellites the variation of LECT is overlaid by a long-term orbital drift. Ignatov et al. (2004) developed a method to describe the drift-based variation of LECT that can be viewed as a formal mathematical approximation of a periodic function with one or two Fourier terms. But, nevertheless, ET is not included in actual studies of LST. Our paper aims to demonstrate the possible influence of equation of time on simple examples of data interpretation, e.g. NDVI.

The calibration and validation test site DEMMIN is infrastructured for hydrological applications based on remote sensing. Operational and automated measurement systems delivers parameters as air temperature and moisture, wind speed and direction, rain, leaf wetness, barometric preasure, incident and reflected solar radiation and incident and emitted thermal radiation, soil temperature and moisture in different depths.

The main goal of TERENO was to create observation platforms on the basis of an interdisciplinary and long‐term aimed research program. By the aid of SoilCan‐lysimeters, an ideal network was built between the four different TERENO‐observatories with their highly instrumented test sites. Within the four TERENO‐observatories at 13 different experimental sites, in total 126 lysimeters were filled monolithically and the measurements were started in October 2010. The lysimeters have been cultivated as grassland or arable land with a standardized crop rotation: winter wheat – winter barley – winter rye – oat.

General conditions of remote sensing: In the next few years, there will be a lot of advanced remote sensing systems availablefor Earth observation. The data collected with help of these systems will be used in the context of GMES. But the analysis of the situation of remote sensing shows that different problems for the data provider and the data users are relevant. The papaer dicusses the problems and possibilities for overcomming some of the identified problems. For this background, the development of DEMMIN as a test site for calibrating and validating remote sensing missions, sensors, data, and value added products (information products) is shown.

One of the main research objectives of the working group Thematic Processors and Validation (TPV) of the Remote Sensing Data Centre (DLR-DFD) is the automation of remote sensing data processing. Whereby, the focal point of research is the derivation of value-added products for agriculture and forestry objectives. Three examples are given to outline past and present research of working group. These are: (1) a standard processor for automated data usability assessment based on multispectral quicklook data; (2) a thematic processor for retrieval of actual evapotranspiration from multispectral image data; and (3) an ongoing research work for the conception of a thematic processor for derivation of soil parameters from hyperspectral image data. Since 1999 DLR Neustrelitz operates the test site DEMMIN (Durable Environmental Multidisciplinary Monitoring Information Network) to assure validation and calibration of data products and algorithms. DEMMIN is an intensively used agricultural ecosystem located in the northeast of Germany and is based on a cooperation between local farmers (IG Demmin) and DLR. It provides a manifold of instrumentation for the measurement of environmental parameters which are stored in the DEMMIN database.

This paper gives an introduction to the agricultural test site DEMMIN which is operated by DLR-DFD since 1999. The paper provides a description of the specific characteristics of the area, the existing data base and its in-situ measuring instrumentation. During the AgriSAR campaign in 2006, numerous airborne radar and optical data sets were acquired over the north-eastern part of DEMMIN. All airborne data acquisitions were accompanied by intensive ground measurements which were carried out by the international AgriSAR team. This paper outlines the contribution of DLR-DFD Neustrelitz which was involved in weekly measurements of vegetation and soil parameters in close cooperation with the Leibniz-Center for Agricultural Landscape Research (ZALF) Müncheberg. The acquired ground data set is presented and discussed in terms of spatial variations and temporal evolution. Data accuracy is evaluated and potential sources of error are pointed out.