Linking Earth Observation and mobile Technologies for improved Decision-Support in Case of Droughts and related Food Insecurity

摘要

Droughts are complex events that constitute a nat-ural part of the climate. Among all natural disasters they show the largest spatio-temporal extent, cause enormous economic loss and numerous casualties. Although droughts pose a threat to both industrialized and developing countries the latter often suffer from chronic poverty and vulnerability, which pave the way for wide-ranging impacts. Earth observation can support aid organizations that are often struggling to cope with the impact of large-scale drought events. However, exploiting the added-value of new technologies requires tools that are adapted to individual user requirements and in-depth knowledge transfer. Within the framework of a project named SATIDA (Satellite Technologies for Improved Drought Risk Assessment) this dissertation links satellite-derived information that aims at the detection of environmental anomalies to information about socio-economic conditions, collected via a corresponding open-source mobile application. The satellite component is based on the combination of different satellite observations (rainfall, soil moisture, land surface temperature and vegetation health) in an Enhanced Combined Drought Index (ECDI). The soil moisture component, which is considered a key variable between atmospheric and land surface conditions, is improved by linking near-real-time (NRT) observations from active and passive microwave sensors to an offline dataset that was generated within the Climate Change Initiative (CCI) of the European Space Agency (ESA). This way, it is possible to detect soil moisture anomalies based on more than 37 years of data (1978-2015). Supported by Doctors without Borders, the tests were conducted in the Central African Republic and in Ethiopia. The dissertation results in three key findings. First, current NRT observations of soil moisture are mature enough to be considered for operational drought monitoring. Second, the method to combine different variables in the ECDI facilitates exploiting the individual strengths of all input datasets, and the robust detection of major drought events. Third, the combination of earth observation and mobile technologies is beneficial for humanitarian aid organizations that aim at pro-active disaster risk reduction.