Seasonal evolution of soil and plant parameters on the agricultural Gebesee test site: a database for the set-up and validation of EO-LDAS and satellite-aided retrieval models

Abstract

Abstract. Ground reference data are a prerequisite for the calibration, update, and validation of retrieval models facilitating the monitoring of land parameters based on Earth Observation data. Here, we describe the acquisition of a comprehensive ground reference database which was created to test and validate the recently developed Earth Observation Land Data Assimilation System (EO-LDAS) and products derived from remote sensing observations in the visible and infrared range. In situ data were collected for seven crop types (winter barley, winter wheat, spring wheat, durum, winter rape, potato, and sugar beet) cultivated on the agricultural Gebesee test site, central Germany, in 2013 and 2014. The database contains information on hyperspectral surface reflectance factors, the evolution of biophysical and biochemical plant parameters, phenology, surface conditions, atmospheric states, and a set of ground control points. Ground reference data were gathered at an approximately weekly resolution and on different spatial scales to investigate variations within and between acreages. In situ data collected less than 1 day apart from satellite acquisitions (RapidEye, SPOT 5, Landsat-7 and -8) with a cloud coverage ≤ 25 % are available for 10 and 15 days in 2013 and 2014, respectively. The measurements show that the investigated growing seasons were characterized by distinct meteorological conditions causing interannual variations in the parameter evolution. Here, the experimental design of the field campaigns, and methods employed in the determination of all parameters, are described in detail. Insights into the database are provided and potential fields of application are discussed. The data will contribute to a further development of crop monitoring methods based on remote sensing techniques. The database is freely available at PANGAEA (https://doi.org/10.1594/PANGAEA.874251).

Quantifying the Sensitivity of NDVI-Based C Factor Estimation and Potential Soil Erosion Prediction using Spaceborne Earth Observation Data

“…The least pronounced impact of heterogeneous soil background reflectance on parcels covered with WR can be explained by the nature of the architectural orientation of the crop canopy. WR, plagiophile canopy, is reported to have a higher plant area index compared with WW (belonging to erectophile), even at the same phenological stage [58]. This can also be inferred from Figure 8 in our study, where, despite both WR and WRy being expected to cover around 75% of the ground in the images dated 02 April 2016 (Table 2), their NDVI values and response to K value categories varied significantly.…”

“…This could be explained to some extent to the variation in patterns of foliar orientation of these crops. WR, Mz and SB categorized as plagiophile and planophile, respectively, while most cereals categorized as erectophile crops behave differently with respect to canopy spectral reflectance [58]. Erecophile canopy, leaves arranged in vertical manner, could trap reflected radiation within the canopy and reduce the NDVI while the opposite is true for planophile canopy orientation types [29].…”

Evaluation of Sentinel-3A and Sentinel-3B ocean land colour instrument green instantaneous fraction of absorbed photosynthetically active radiation

“…7e). The fact that, over DE-Geb, all seasonal features are different compared to the climatology is mainly due to the rotation of different crops (Truckenbrodt and Baade, 2018). These features were confirmed using alternative space products (not shown here).…”