LimnoVIS - A Robotic Surface Vehicle for Spectral Measurements in Inland Waters

Spectral measurements in aquatic remote sensing are usually carried out from ships, boats or stationary platforms. While the latter only covers a single location, mobile platforms can introduce significant errors due to unexpected movement (drift and rotation), reflection and shadowing effects from the ship’s hull, superstructures and the personnel conducting the measurements. To overcome these caveats, we developed the low-profile robotic platform LimnoVIS that can be operated autonomously or remotely controlled and is capable of keeping its position and orientation accurately through its omnidirectional maneuverability. The onboard measurement system comprises a VIS/NIR spectrometer (350-880 nm, 1 nm resolution) which is connected to four different optics via a fiber optical switch. This allows for rapid subsequent measurement of upwelling radiance above and under water, sky radiance and downwelling irradiance using reflectance standards or a cosine corrector, all by the same spectrometer. LimnoVIS carries also a profiler, which can be lowered by up to 30 m. It is equipped with a spectrometer and a tiltable diffusor for measuring benthic reflectance, LED and halogen lamps, a laser range finder, a camera, and sensors for temperature and pressure. Multiple onboard cameras with recording and live viewing capabilities are used for navigation, visual supervision and documentation of the measurements and for compiling shallow-water orthomosaics. Furthermore, LimnoVIS is equipped with a sonar for deriving bathymetry in the range of 0.5 to 30 m

ProGIRH-DLR: Remote sensing of water quality in the Mantaro River basin through spaceborne and ground-based acquisition of multi- and hyperspectral data

Peru is amongst the most affected countries by climate change in the world, with severe consequences on the availability of water across the country. The GIZ funded project "Multisectoral management of water resources in the Mantaro River basin" (ProGIRH) aims to improve the integrated and climate-sensitive water resource management in the Mantaro River basin. Within this framework, an IMF Team supports the Peruvian national water authority (ANA) in establishing remote sensing methodologies as a complement to traditional sampling-based water analysis. With a permanent focus on capacity building of the regional partners, the Team combines multi- and hyperspectral satellite imagery with in-situ spectral data, in order to define the possibilities and technical requirements necessary to establish a self-dependent and locally managed long-term observation of water quality and availability

ProGIRH-DLR: Remote sensing of water quality in the Mantaro River basin through spaceborne and ground-based acquisition of multi- and hyperspectral data

Peru is amongst the most affected countries by climate change in the world, with severe consequences on the availability of water across the country. The GIZ funded project "Multisectoral management of water resources in the Mantaro River basin" (ProGIRH) aims to improve the integrated and climate-sensitive water resource management in the Mantaro River basin. Within this framework, an IMF Team supports the Peruvian national water authority (ANA) in establishing remote sensing methodologies as a complement to traditional sampling-based water analysis. With a permanent focus on capacity building of the regional partners, the Team combines multi- and hyperspectral satellite imagery with in-situ spectral data, in order to define the possibilities and technical requirements necessary to establish a self-dependent and locally managed long-term observation of water quality and availability

The metrology system of the VLTI instrument GRAVITY

The VLTI instrument GRAVITY combines the beams from four telescopes and provides phase-referenced imaging as well as precision-astrometry of order 10 microarcseconds by observing two celestial objects in dual-field mode. Their angular separation can be determined from their differential OPD (dOPD) when the internal dOPDs in the interferometer are known. Here, we present the general overview of the novel metrology system which performs these measurements. The metrology consists of a three-beam laser system and a homodyne detection scheme for three-beam interference using phase-shifting interferometry in combination with lock-in amplifiers. Via this approach the metrology system measures dOPDs on a nanometer-level.Comment: 9 pages, 5 figure

Water quality monitoring in Térraba Sièrpe Wetland (Costa Rica) using multi- and hyperspectral EO data

The project MONEOWET focuses on multispectral and hyperspectral Earth Observation (EO) data to investigate water quality in relation to agricultural activities within the Térraba Sièrpe Wetland in Costa Rica. This study corresponds to an initiative focused on investigating the applicability of remote sensing data in tropical systems. The main topic of this project is the use of EO data to assess the impacts and dynamics of agricultural activities on the sensitive RAMSAR wetland ecosystem Térraba Sièrpe at the mouth of the Térraba and Sièrpe rivers. One goal of this project is to develop a first EO database and define analytical methods for water quality studies in that area and beyond. The results will provide a deeper insight into the processes of the entire wetland ecosystem and may help to detect harmful damage to the fragile environment caused by surrounding agricultural activities. The long-term goal is sustainable water and land use management that is exemplary for many other tropical wetlands in Latin America. Scientists from Germany and Costa Rica are working together to collect data with established (e.g. Sentinel 2, Landsat 8) and new Earth Observation sensors (e.g. DESIS on the ISS) to assess water quality parameters and link these parameters to agricultural land use in the surrounding area. The common goal of the project is to evaluate the applicability of Landsat 8, Sentinel-2 and DESIS multi- and hyperspectral satellite imagery for water quality studies in tropical environments. Field campaigns were carried out during wet season (November 2018 and November 2019) and dry season (March 2019 and March 2021). The sampling sites for in-situ measurements were taken in the three main meanders of the Sièrpe River and the main meander of Térraba River within the wetland. At each sampling site, the spectral signature of the river was recorded using an Ocean Optics Sensor System (OOSS). The multispectral (Sentinel 2, Landsat 8) and hyperspectral EO (DESIS) data were atmospherically corrected to Bottom-of-atmosphere (BOA) reflectance using Sen2cor (ESA) and PACO (Python-based Atmospheric Correction, DLR), respectively. The WASI-2D inversion method, a semi-analytical model, which retrieves the optically active water quality variables: chlorophyll, total suspended matter (TSM) and colored dissolved organic matter (CDOM) was used and parameterized with site - specific inherent optical properties (SIOPs) of the area and applied to time series of L2A Sentinel, Landsat 8 and DESIS images. Some of the Sentinel-2 and Landsat overpasses were coincident with available field data, however DESIS images could not be obtained during field campaigns, thus only a qualitative evaluation is presented. Although cloud cover in the tropics is a major challenge, the influence of thin clouds could be corrected and the concentrations of TSM and CDOM could be derived quantitatively. Chlorophyll could not be derived reliably in most areas, in particular not from Landsat 8, most likely because its concentration was relatively low and water absorption was dominated by CDOM. The high temporal dynamics of the river system, which is strongly influenced by tides, makes comparison of satellite data collected at different times very difficult, as is comparison with field data. Nevertheless, Sentinel 2-derived maps of water constituents and corresponding Landsat 8 and DESIS images show good agreements in the average concentrations of TSM and CDOM concentration and plausible spatial patterns, and field measurements show that they are in a plausible range. The results indicate that under favorable observational and environmental conditions, the applied atmospheric correction and the used retrieval algorithm are suitable to use DESIS, Sentinel 2 and Landsat 8 data for mapping TSM and CDOM in tropical environments, while chlorophyll is challenging. Their quantitative determination by satellite is therefore an important contribution of this project to the ecological assessment of the waters and the surrounding environment of the study area

In vivo efficacy of the boron-pleuromutilin AN11251 against Wolbachia of the rodent filarial nematode Litomosoides sigmodontis

The elimination of filarial diseases such as onchocerciasis and lymphatic filariasis is hampered by the lack of a macrofilaricidal – adult worm killing – drug. In the present study, we tested the in vivo efficacy of AN11251, a boron-pleuromutilin that targets endosymbiotic Wolbachia bacteria from filarial nematodes and compared its efficacy to doxycycline and rifampicin. Doxycycline and rifampicin that were previously shown to deplete Wolbachia endosymbionts leading to a permanent sterilization of the female adult filariae and adult worm death in human clinical studies. Twice-daily oral treatment of Litomosoides sigmodontis-infected mice with 200 mg/kg AN11251 for 10 days achieved a Wolbachia depletion > 99.9% in the adult worms, exceeding the Wolbachia reduction by 10-day treatments with bioequivalent human doses of doxycycline and a similar reduction as high-dose rifampicin (35 mg/kg). Wolbachia reductions of > 99% were also accomplished by 14 days of oral AN11251 at a lower twice-daily dose (50 mg/kg) or once-per-day 200 mg/kg AN11251 treatments. The combinations tested of AN11251 with doxycycline had no clear beneficial impact on Wolbachia depletion, achieving a > 97% Wolbachia reduction with 7 days of treatment. These results indicate that AN11251 is superior to doxycycline and comparable to high-dose rifampicin in the L. sigmodontis mouse model, allowing treatment regimens as short as 10-14 days. Therefore, AN11251 is represents a promising pre-clinical candidate that was identified in the L. sigmodontis model, and could be further evaluated and developed as potential clinical candidate for human lymphatic filariasis and onchocerciasis.  AUTHOR SUMMARY Onchocerciasis and lymphatic filariasis are human filarial tropical diseases, which can cause blindness and severe dermatitis (onchocerciasis) or lymphedema and hydrocele (lymphatic filariasis). Current strategies to eliminate these diseases include the mass drug administration (MDA) of drugs that target the progeny of the filariae, the microfilariae, and temporarily inhibit filarial embryogenesis and, therefore, the transmission of the disease. However, MDA has several limitations that delay the goal of elimination including the lack of a drug with a short term regimen and a potent macrofilaricidal effect. As an alternative approach, the antibiotic doxycycline has been proven to be effective in depleting Wolbachia endosymbionts from adult filariae, which then leads to permanent sterilization and death of the adult worms. Due to contraindications for doxycycline and prolonged treatment regimen of at least 4 weeks, there is an urgent need for new anti-filarial drugs with an improved safety profile and shorter regimens. The current study demonstrates that the boron-pleuromutilin derivative AN11251 provides an excellent in vivo anti-Wolbachia depletion in the Litomosoides sigmodontis filarial mouse model that is superior to doxycycline and comparable to rifampicin, allowing for regimens as short as 10-14 days. Combination with doxycycline for 7 days had no significant beneficial effect on efficacy, achieving Wolbachia reductions of more than 97%. Therefore, AN11251 shows potent anti-Wolbachia activity in the L. sigmodontis mouse model and may also present an alternative pre-clinical candidate for filariasis treatment

Building Tomograph – From Remote Sensing Data of Existing Buildings to Building Energy Simulation Input

Existing buildings often have low energy efficiency standards. For the preparation of retrofits, reliable high-quality data about the status quo is required. However, state-of-the-art analysis methods mainly rely on on-site inspections by experts and hence tend to be cost-intensive. In addition, some of the necessary devices need to be installed inside the buildings. As a consequence, owners hesitate to obtain sufficient information about potential refurbishment measures for their houses and underestimate possible savings. Remote sensing measurement technologies have the potential to provide an easy-to-use and automatable way to energetically analyze existing buildings objectively. To prepare an energetic simulation of the status quo and of possible retrofit scenarios, remote sensing data from different data sources have to be merged and combined with additional knowledge about the building. This contribution presents the current state of a project on the development of new and the optimization of conventional data acquisition methods for the energetic analysis of existing buildings solely based on contactless measurements, general information about the building, and data that residents can obtain with little effort. For the example of a single-family house in Morschenich, Germany, geometrical, semantical, and physical information are derived from photogrammetry and quantitative infrared measurements. Both are performed with the help of unmanned aerial vehicles (UAVs) and are compared to conventional methods for energy efficiency analysis regarding accuracy of and necessary effort for input data for building energy simulation. The concept of an object-oriented building model for measurement data processing is presented. Furthermore, an outlook is given on the project involving advanced remote sensing techniques such as ultrasound and microwave radar application for the measurement of additional energetic building parameters

ERIS: revitalising an adaptive optics instrument for the VLT

ERIS is an instrument that will both extend and enhance the fundamental diffraction limited imaging and spectroscopy capability for the VLT. It will replace two instruments that are now being maintained beyond their operational lifetimes, combine their functionality on a single focus, provide a new wavefront sensing module that makes use of the facility Adaptive Optics System, and considerably improve their performance. The instrument will be competitive with respect to JWST in several regimes, and has outstanding potential for studies of the Galactic Center, exoplanets, and high redshift galaxies. ERIS had its final design review in 2017, and is expected to be on sky in 2020. This contribution describes the instrument concept, outlines its expected performance, and highlights where it will most excel.Comment: 12 pages, Proc SPIE 10702 "Ground-Based and Airborne Instrumentation for Astronomy VII