The EnMAP Observation Planning and Data Access for Scientific Users

EnMAP (Environmental Mapping and Analysis Program; www.enmap.org) is the first German imaging spectroscopy mission, to be launched in April 2022. After its Launch, Early Orbit and Commissioning Phase (6 months), the EnMAP mission will be available to the international user community for the data access and ordering process. EnMAP will be operated by the German Aerospace Center (DLR) covering all aspects relevant to assure successful mission operations. This comprises controlling and commanding the satellite using multi-mission infrastructures as well as observation planning, data reception, hyperspectral data processing including calibration, data archiving, data access and delivery, and providing web-interfaces to the international user community. This presentation will give an overview of EnMAP observation planning and data access concepts and outlines the data ordering workflow in particular for scientific users. The user can get access to EnMAP data using two different order options: On the one hand the user can submit future order requests through the EnMAP Data Access Portal (EDAP). The EDAP links to a set of functions for registered users that will support the international user community. This portal includes amongst others the proposal portal allowing submission of proposal for all scientific users responding to a Data Announcement of Opportunity (AO) and the Observation Request Portal providing planning support of observation requests and allowing submission of future orders. On the other hand, the already recorded data can be searched, processed and delivered based on catalogue from the archive through the EOWEB® GeoPortal. Although EnMAP is based on an open data policy and every type of user is in principle entitled to download data and request acquisitions, there will be different user categories to set acquisition priorities. The scientific (Cat-1) orders has higher priority and is requested to submit a proposal, which will undergo a scientific evaluation. The associated results will be presented by an interactive map supporting the establishment of a worldwide user network and guarantee the highest transparency of the proposal process. In the Observation Portal the user is able to submit future order requests by specifying following order parameters, such as the geographic area of interest (AOI) (between 74° North and 74° South), length of the AOI as a multiple of 30 km and up to 1000 km, the specification of the maximum allowable tilt angle of the satellite across the orbit (5° to 30°), the time span in which the acquisition should be performed and the option for time series and the number of data takes per months. To ensure acceptable illumination conditions, only images with sun zenith angle lower 60° will be considered. As for data acquisition EnMAP will be able to collect 5000 km along track and 30 km across track per day. The probability that the order will be included in the mission planning depends on the requirements for the observation as well as the specified priority and quota. Whether a specific data take is scheduled at the end depends on factors such as e.g. available data storage, cloud probabilities (e.g. historical and predicted cloud coverage) and, if requested by the user, sunglint probability (this is relevant for water products only). Users should make a request at least 25 hours before the scheduled recording to ensure the uplink. All data are available no later than 24 hours after collection for further processing into data products. The EnMAP ground segment will provide a range of standardized data products with different levels of processing of Level 1B, Level 1C and Level 2A based on archived Level 0 comprising extensive quicklooks and metadata. Due to required multiple processing options, each product is generated specifically for the order and delivered using FTPS (FTP with SSL) provided by multi-mission facilities

Challenges of Harmonizing 40 Years of AVHRR Data: The TIMELINE Experience

Earth Observation satellite data allows for the monitoring of the surface of our planet at predefined intervals covering large areas. However, there is only one medium resolution sensor family in orbit that enables an observation time span of 40 and more years at a daily repeat interval. This is the AVHRR sensor family. If we want to investigate the long-term impacts of climate change on our environment, we can only do so based on data that remains available for several decades. If we then want to investigate processes with respect to climate change, we need very high temporal resolution enabling the generation of long-term time series and the derivation of related statistical parameters such as mean, variability, anomalies, and trends. The challenges to generating a well calibrated and harmonized 40-year-long time series based on AVHRR sensor data flown on 14 different platforms are enormous. However, only extremely thorough pre-processing and harmonization ensures that trends found in the data are real trends and not sensor-related (or other) artefacts. The generation of European-wide time series as a basis for the derivation of a multitude of parameters is therefore an extremely challenging task, the details of which are presented in this paper