Inland water level and its dynamics are key components in the global water cycle and land surface hydrology, significantly influencing climate variability and water resource management. Satellite observations, in particular altimetry missions, provide inland water level time series for nearly three decades. Space-based remote sensing is regarded as a cost-effective technique that provides measurements of global coverage and homogeneous accuracy in contrast to in-situ sensors. The advent of Open-Loop Tracking Command (OLTC), and Synthetic Aperture Radar (SAR) mode strengthened the use of altimetry missions for inland water level monitoring. However, it is still very challenging to obtain accurate measurements of water level over narrow rivers and small lakes. This scoping systematic literature review summarizes and disseminates the research findings, highlights major results, and presents the limitations regarding inland water level monitoring from satellite observations between 2018 and 2022. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and through a double screening process, 48 scientific publications were selected meeting the eligibility criteria. To summarize the achievements of the previous 5 years, we present fundamental statistical results of the publications, such as the annual number of publications, scientific journals, keywords, and study regions per continent and type of inland water body. Also, publications associated with specific satellite missions were analyzed. The findings show that Sentinel-3 is the dominant satellite mission, while the ICESat-2 laser altimetry mission has exhibited a high growth trend. Furthermore, publications including radar altimetry missions were charted based on the retracking algorithms, presenting the novel and improved methods of the last five years. Moreover, this review confirms that there is a lack of research on the collaboration of altimetry data with machine learning techniques.

WeObserve delivered the first European-wide Citizen Observatory (CO) knowledge platform to share best practices, to address challenges and to inform practitioners, policy makers and funders of COs. We present key insights from WeObserve activities into leveraging challenges to create interlinked solutions, connecting with international frameworks and groups, advancing the field through communities of practice and practitioner networks, and fostering an enabling environment for COs. We also discuss how the new Horizon Europe funding programme can help to further advance the CO concept, and vice versa, how COs can provide a suitable mechanism to support the ambitions of Horizon Europe.

Desert ecosystems are particularly vulnerable to global climate change, characterized by increased temperatures, variable intensity and frequency in precipitation and increased atmospheric CO2 levels. Under such conditions, substantial alterations in their structure and functioning of desert ecosystems is expected. This climate shift poses a serious threat to species adapted to deserts, especially endemic plants, which are susceptible to the potential loss of suitable habitats. Further to that, neighboring populated areas are also exposed to adverse conditions characterized by poor air quality, with direct impacts on human health, the economy and the environment overall. To address these challenges, the CiROCCO Project aims to implement a robust yet cost-effective Internet of Things (IoT) system for environmental measurements in harsh desert environments. Such a system not only enhances data accuracy but also enables continuous monitoring, reduces costs, and supports critical research and conservation efforts considering climate change and ecosystem challenges. The proposed IoT system primarily relies on a network of distributed low-cost Wireless Sensor Nodes (WSNs) that have the capability to monitor the surrounding environment and measure various crucial meteorological and air quality parameters, including inter alia air and sand/soil temperature, solar radiation, Ozone, PM2.5, PM10, with accuracy comparable to commercial high-end nodes offering similar measurements. Additionally, communication gateways are employed to collect measurements from the distributed WSNs using low-power consumption protocols such as Bluetooth Low Energy (BLE) and LoRaWAN. The collected measurements are then standardized into JSON messages, including the unique identifier of the device, timestamp, and parameter values. Subsequently, the data are transmitted wirelessly to the cloud using the most suitable method based on network connectivity. If there is an available Wi-Fi network in the field, the data is prioritized for transmission through this network. Alternatively, the system utilizes the 4G or 5G network in the area. In cases where none of these networks is accessible, the data is transmitted to the cloud through satellite communications. This method involves an additional satellite device connected to the gateway, where the formatted messages are loaded through serial communications. The satellite device awaits the next pass of the nanosatellite, for uploading the measurements. The nanosatellite continues its journey until it passes by a base station, at which point the data are downloaded, stored in the base station portal, and made available to third-party applications through the portal API. In conclusion, the scientific approach outlined in this work addresses the imposing challenges of collecting valuable in-situ data for monitoring climatic conditions in hard-to-reach under-sampled environments. The development of low-cost devices, including WSNs and gateways with IoT capabilities, is crucial for advancing research and conservation efforts in the context of climate change and considering the unique challenges posed on desert ecosystems.AKNOWLEDGMENTS This research work is part of the CiROCCO Project. CiROCCO Project is funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or REA. Neither the European Union nor the granting authority can be held responsible for them.