The Yellow River Basin in Transition Multi-faceted Land Cover Change Analysis in the Yellow River Basin in the Context of Global Change Using Multi-sensor Remote Sensing Imagery Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Julius-Maximilians-Universität Würzburg vorgelegt von Christian Wohlfart Juli 2017 eingereicht am: 27.07.2017 von Christian Wohlfart Gutachter: PD Dr. habil. Claudia Künzer PD Dr. habil. Christopher Conrad Prof Dr. Roland Baumhauer Prüfer: PD Dr. habil. Claudia Künzer Prof. Dr. Barbara Sponholz Tag der mündlichen Prüfung: 25.04.2018 (Titelbild: Südlicher Teil des Löss Plateaus (Landsat 8 OLI Aufnahme, Bandkombination: 6,5,4)) This dissertation was prepared at the German Remote Sensing Data Center (DFD) of the Ger- man Aerospace Center (DLR), Oberpfaffenhofen in joint cooperation with the Company for Remote Sensing and Environmental Research (SLU), Munich. you are unaware of your obscure sources but you are explicitly sure of “ the vast sea as your final destination you always frown with your brownish wrinkles but you prefer a nonpro- fessional smile on your face your only luggage of life all your teeth have been lost or pulled out but you keep licking the muddy banks with your heart despite your dreams forged your song is no more than a foam of silence but you struggle hard to remain afloat on the sea of noise beyond the borderline of heaven your love for the loess plateau often overturns and overflows but you have never flooded the valley of the dragon’s mind since confucius’s times your course ahead is crowded with holes and crevices but you will deliver your promises to every unevenness instead of promising the deliveries only you occupy an enormously tiny place of the world but you feed all the hopes and wishes of those with thirsty mouths stranded ashore you flow down from the sky created by yourself but you hope to avoid falling on the broken floor of your own church you may be tortured or burned to steam but you will eventually find your impossible way to the sea of blue sky ” Changming Yuan, Nine Detours of the Yellow River SUMMARY s a cradle of ancient Chinese civilization, the Yellow River Basin has a very long human-environment interrelationship, where early anthropogenic activities re- Asulted in large scale landscape modifications. Today, the impact of this relationship has intensified further as the basin plays a vital role for China’s continued economic development. It is one of the most densely-populated, fastest growing, and most dynamic regions of China with abundant natural and environmental resources providing a liveli- hood for almost 190 million people. Triggered by fundamental economic reforms, the basin has witnessed a spectacular economic boom during the last decades and can be considered as an exemplary blueprint region for contemporary dynamic Global Change processes occurring throughout the country, which is currently transitioning from an agrarian-dominated economy into a modern urbanized society. However, this resources- demanding growth has led to profound land use changes with adverse effects on the Yellow River social-ecological systems, where complex challenges arise threatening a long-term sustainable development. Consistent and continuous remote sensing-based monitoring of recent and past land cover and land use change is a fundamental requirement to mitigate the adverse impacts of Global Change processes. Nowadays, technical advancement and the multitude of available satellite sensors, in combination with the opening of data archives, allow the creation of new research perspectives in regional land cover applications over heteroge- neous landscapes at large spatial scales. Despite the urgent need to better understand the prevailing dynamics and underlying factors influencing the current processes, detailed regional specific land cover data and change information are surprisingly absent for this region. In view of the noted research gaps and contemporary developments, three major objec- tives are defined in this thesis. First (i), the current and most pressing social-ecological challenges are elaborated and policy and management instruments towards more sus- tainability are discussed. Second (ii), this thesis provides new and improved insights on the current land cover state and dynamics of the entire Yellow River Basin. Finally (iii), the most dominant processes related to mining, agriculture, forest, and urban dynamics are determined on finer spatial and temporal scales. The complex and manifold problems and challenges that result from long-term abuse of the water and land resources in the basin have been underpinned by policy choices, cultural attitude, and institutions that have evolved over centuries in China. The tremen- dous economic growth that has been mainly achieved by extracting water and exploiting land resources in a rigorous, but unsustainable manner, might not only offset the eco- nomic benefits, but could also foster social unrest. Since the early emergence of the first ii Chinese dynasties, flooding was considered historically as a primary issue in river man- agement and major achievements have been made to tame the wild nature of the Yellow River. Whereas flooding is therefore largely now under control, new environmental and social problems have evolved, including soil and water pollution, ecological degradation, biodiversity decline, and food security, all being further aggravated by anthropogenic climate change. To resolve the contemporary and complex challenges, many individual environmental laws and regulations have been enacted by various Chinese ministries. However, these policies often pursue different, often contradictory goals, are too general to tackle specific problems and are usually implemented by a strong top-down approach. Recently, more flexible economic and market-based incentives (pricing, tradable permits, investments) have been successfully adopted, which are specifically tailored to the re- spective needs, shifting now away from the pure command and regulating instruments. One way towards a more holistic and integrated river basin management could be the establishment of a common platform (e.g. a Geographical Information System) for data handling and sharing, possibly operated by the Yellow River Basin Conservancy Commis- sion (YRCC), where available spatial data, statistical information and in-situ measures are coalesced, on which sustainable decision-making could be based. So far, the collected data is hardly accessible, fragmented, inconsistent, or outdated. The first step to address the absence and lack of consistent and spatially up-to-date information for the entire basin capturing the heterogeneous landscape conditions was taken up in this thesis. Land cover characteristics and dynamics were derived from the last decade for the years 2003 and 2013, based on optical medium-resolution high- temporal MODIS Normalized Differenced Vegetation Index (NDVI) time series at 250 m. To minimize the inherent influence of atmospheric and geometric interferences found in raw high temporal data, the applied adaptive Savitzky-Golay filter successfully smoothed the time series and substantially reduced noise. Based on the smoothed time series data, a large variety of intra-annual phenology metrics as well as spectral and multi- spectral annual statistics were derived, which served as input variables for random forest (RF) classifiers. High quality reference data sets were derived from very high resolution imagery for each year independently of which 70 % trained the RF models. The accuracy assessments for all regionally specific defined thematic classes were based on the remaining 30 % reference data split and yielded overall accuracies of 87 % and 84 % for 2003 and 2013, respectively. The first regional adapted Yellow River Land Cover Products (YRB LC) depict the detail spatial extent and distribution of the current land cover status and dynamics. The novel products overall differentiate overall 18 land cover and use classes, including classes of natural vegetation (terrestrial and aquatic), cultivated classes, mosaic classes, non-vegetated, and artificial classes, which are not presented in previous land cover studies so far. Building on this, an extended multi-faceted land cover analysis on the most prominent land cover change types at finer spatial and temporal scales provides a better and more detailed picture of the Yellow River Basin dynamics. Precise spatio-temporal products about mining, agriculture, forest, and urban areas were examined from long-trem Landsat satellite time series monitored at annual scales to capture the rapid rate of change in four selected focus regions. All archived Landsat images between 2000 and 2015 were used to derive spatially continuous spectral-temporal, multi-spectral, and textural metrics. For each thematic region and year RF models were built, trained and tested based on a stable- pixels reference data set. The automated adaptive signature (AASG) algorithm identifies iii those pixels that did not change between the investigated time periods to generate a mono-temporal reference stable-pixels data set to keep manual sampling requirements to a minimum level. Derived results gained high accuracies ranging from 88 % to 98 %. Throughout the basin, afforestation on the Central Loess Plateau and urban sprawl are identified as most prominent drivers of land cover change, whereas agricultural land remained stable, only showing local small-scale dynamics. Mining operations started in 2004 on the Qinghai-Tibet