Laboratory for
Climatology and Remote Sensing

Abstract:

The current study investigates existing infrastructure, its technical solutions and implemented standards for data repositories related to integrative biodiversity research. The storage and reuse of complex biodiversity data in central databases are becoming increasingly important, particularly in attempts to cope with the impacts of environmental change on biodiversity and ecosystems. From the data side, the main challenge of biodiversity repositories is to deal with the highly interdisciplinary and heterogeneous character of standardized and unstandardized data and metadata covering information from genes to ecosystems. Furthermore, the technical improvements in data acquisition techniques produce ever larger data volumes, which represent a challenge for database structure and proper data exchange. The current study is based on comprehensive in-depth interviews and an online survey addressing IT specialists involved in database development and operation. The results show that metadata are already well established, but that non-meta data still is largely unstandardized across various scientific communities. For example, only a third of all repositories in our investigation use internationally unified semantic standard checklists for taxonomy. The study also showed that database developers are mostly occupied with the implementation of state of the art technology and solving operational problems, leaving no time to implement user's requirements. One of the main reasons for this dissatisfying situation is the undersized and unreliable funding situation of most repositories, as reflected by the marginally small number of permanent IT staff members. We conclude that a sustainable data management system that fosters the future use and reuse of these valuable data resources requires the development of fewer, but more permanent data repositories using commonly accepted standards for their long-term data. This can only be accomplished through the consolidation of hitherto widely scattered small and non-permanent repositories.

Abstract:

Tropical mountain forest in the Andes of southeastern Ecuador is regularly destroyed to gain pasture land by cultivating the C4 grass Setaria sphacelata. After recurrent burning of the pastures, the grass is partly outcompeted by the C3 southern bracken (Pteridium arachnoideum). This competition represents the problematic of pasture degradation and increasing deforestation, due to the necessity of new pasture land. Because no information on the growth potential of both species in the Andes of Ecuador is available, a growth simulation model has been improved and properly parameterized with field observations. The measured species- and site-specific physiological and edaphic parameters are presented in this paper, as well as the model validation with field observations of leaf CO2 assimilation. The validation showed deviations of simulated from observed leaf net assimilation lower than 5% of the observed values. The validated model was run with a fully realistic meteorological forcing of the year 2008 (10 min time step). The main result points to slightly higher growth potential of Setaria with 5879 g m?2 a?1, based on an annual CO2 net assimilation rate of 217 mol CO2 m?2 a?1. The calculated growth potential of bracken was 5554 g m?2 a?1, based on the CO2 net assimilation of 197 mol CO2 m?2 a?1. In addition, it was shown that decreasing incoming solar radiation and low temperature are favourable weather conditions for bracken in contrary to the pasture grass Setaria.

Abstract:

Data sharing has become an important issue in modern biodiversity research to address large scale questions. Despite the steadily growing scientific demand, data are not easily accessed. Why is this the case? This study explores the reasons for the reluctance to share data on the one hand and the motivations for sharing on the other by summarising results from > 60 interviews and > 700 survey participants within the biodiversity science community. As result, there is a clear commitment to share biodiversity data, but also a reluctance to actually do so due to a mixture of social and technical impediments, such as loss of control over data and lack of professional reward for sharing. This exploratory study summarises the formal and technical requirements for data sharing and reuse, stated by voluntarily participating scientists worldwide. To ensure sustainable data use, user friendly data infrastructure have to be expanded or newly designed, data management plans for all scientific investigations have to be promoted, training for the users has to be provided and motivational aspects at all stages of data submission and re-use have to be considered.

Abstract:

Research on biodiversity, its relation to ecosystem functioning and services, and the assessment of the impacts of environmental change on biodiversity needs an interdisciplinary perspective. This implies a great diversity of data and data formats gathered mostly in short- to mid-term collaborative research projects. It has been common practice that projects develop specific data management and communication solutions. We compare solutions of two major German collaborative research programs in functional biodiversity research to derive functional commonalities. This in-depth analysis follows five categories of the data life cycle: (i) data acquisition, (ii) metadata management, (iii) database, (iv) exploration, analysis and visualization, and (v) data curation and preservation. The results show that even though both systems were developed completely independently, they reveal comparable overall features and a similar state of implementation. Major focus areas lie in the implementation of comparable metadata schemas and their importance for storage and access strategies for tabular data on the value level. Basic analysis tools and similar management functions are considered. Intensive communication with the users and the orientation of ongoing developments based on user requirements is also important. Both systems are different mostly in specific details which, however, do not influence the overall comparable performance. It should be also emphasized that the same functionality is achieved with completely different software. The choice of software is based on the evaluation of available technologies. Thereby it might be influenced by individual experiences of the developers, but is mainly determined by the data diversity, which forces the usage of flexible technologies to develop adaptable systems. It is concluded that overall features for project databases of collaborative research projects must be supplemented by sophisticated data description, storage, and analysis structures to serve the requirements of integrative functional biodiversity research.

Abstract:

The aim of this study was to proof applicability of hyperspectral imaging for the analysis and classification of human mucosal surfaces in vivo. The larynx as a prototypical anatomically well-defined surgical test area was analyzed by microlaryngoscopy with a polychromatic lightsource and a synchronous triggered monochromatic CCD-camera. Image stacks (5 benign, 7 malignant tumors) were analyzed by established software (principal component analysis PCA, hyperspectral classification, spectral profiles). Hyperspectral image datacubes were analyzed and classified by conventional software. In PCA, images at 590–680 nm loaded most onto the first PC which typically contained 95% of the total information. Hyperspectral classification clustered the data highlighting altered mucosa. The spectral profiles clearly differed between the different groups. Hyperspectral imaging can be applied to mucosal surfaces. This approach opens the way to analyze spectral characteristics of histologically different lesions in order to build up a spectral library and to allow non-touch optical biopsy.

Abstract:

• Additional water supplied by dew formation is an important resource for microbes, plants and animals in precipitation-limited habitats, but has received little attention in tropical forests until now. • We evaluated the micro-environmental conditions of tree stem surfaces and their epiphytic organisms in a neotropical forest, and present evidence for a novel mechanism of diurnal dew formation on these surfaces until midday that has physiological implications for corticolous epiphytes such as lichens. • In the understorey of a lowland forest in French Guiana, heat storage of stems during the day and delayed radiative loss during the night decreased stem surface temperatures by 6?C in comparison to the dew-point temperature of ambient air. This measured phenomenon induced modelled totals of diurnal dew formation between 0.29 and 0.69 mm d )1 on the surface of the bark and the lichens until early afternoon. • Crustose lichens substantially benefit from this dew formation, because it prolongs photo- synthetic activity. This previously unrecognized mechanism of midday dew formation contrib- utes to the water supply of most corticolous organisms, and may be a general feature in forest habitats world-wide

Abstract:

The vertical distribution of liquid water content (LWC) in natural fog and low stratus is a crucial variable in many applications, e.g. the development of satellite based retrievals of ground fog. Unfortunately, there is very little data concerning fog LWC-profiles, mainly due to the lack of suitable operational instrumentation. A novel ground-based 94 GHz FMCW cloud radar could fill this gap if radar reflectivity Z could be converted to LWC by using appropriate Z–LWC relations. However, this relation strongly depends on drop size distribution (DSD) and is hardly known for natural fog types. In this sensitivity study, the influence of the DSD on the Z–LWC relation in different types and life cycle stages of natural fogs is analyzed using a radiative transfer code (RTC) and published fog drop size distributions. It could be shown that there is a direct but nonlinear relationship between LWC and radar reflectivity. The proportionality factor of the Z–LWC equation in particular reveals specific ranges for the different life cycle stages. If a proper classification of fog life cycle in the field is possible, the results could be used to properly convert Z to LWC.

Abstract:

The thermal structure of a megadiverse mountain ecosystem in southern Ecuador is examined on the basis of temperature measurements inside the natural mountain forest and at open sites along an altitudinal gradient from 1700m to 3200m. The data is used to calculated maps of monthly average minimum, mean and maximum 2m air temperature for the period 1999-2007, needed by ecological projects. The maps are generated by combining the straightforward detrending technique by using a Digital Elevation Model and satellite-based land cover classification. The results reveal a clear thermal differentiation over the year, partly triggered by the change of synoptic weather situation but also by land cover effects. Thermal amplitudes are particularly low during the main rainy season when cloudiness and air humidity are high but markedly pronounced in the relative dry season when daily irradiance and outgoing nocturnal radiation causes distinct differences between the land cover units. Particularly the lower pasture areas gained by slash and burn of the natural forest exhibit the most extreme thermal conditions while the atmosphere inside the mountain forest is slightly cooler due to the regulating effects of the dense vegetation. Thus, clearing the forest clearly reduces the thermal regulation function (regulating ecosystem services) of the ecosystem which might become problematic under future global warming.

Abstract:

The detection of ground fog from satellite data is of interest in operational nowcasting applications, as well as in studies of the climate system. A discrimination between fog at the ground and other low-stratus situations from satellite data requires information on cloud vertical geometry to establish whether the cloud touches the ground. This article introduces a technique that allows for the discrimination between low stratus and (ground) fog on the basis of geostationary satellite imagery. The cloud-base height is derived using a subadiabatic model of cloud microphysics. In this model, the cloud base is varied until model liquid–water path matches that retrieved from satellite data. The performance of this technique is shown to be good in a comparison with METeorological Aerodrome Report data comprising 1030 satellite scenes. With a hit rate of 81% and a threat score of 0.62, the skill is satisfactory.

Abstract:

As part of an interdisciplinary research programme, the spatial and temporal variability of precipitation in southern Ecuador has been investigated since January 2002. The study site is located at the northern margin of the Podocarpus National Park in the vicinity of Loja, about 500 km south of Quito, at altitudes ranging from 1800 to 3200 m.a.s.l. Due to its low density, the conventional rainfall station network fails to register the highly variable spatial distribution of rain, whereas contributions by fog are not accounted at all. Hence, for the first time in a tropical montane forest setting, a weather radar was used, covering a radius of 60 km and reaching from the Amazon Basin to the coastal plains of the region. Furthermore, a network of sampling stations supplies data about the altitudinal gradient of fog and rainwater inputs. The precipitation distribution in the study area proves to be far more variable than previously thought and is strongly coupled to the orographic characteristics and the special topographical setting of the landscape. Maxima in precipitation occur especially in the eastern parts of the radar range on slopes exposed to advected moisture from the Amazon Basin, whereas the highest crests of the Andes receive less precipitation. The study area has two cloud condensation levels, occurring at 1500–2000 and 2500–3500 m.a.s.l., respectively. At 1800–2000 m.a.s.l., fog is estimated to contribute an additional input of 5% of conventionally measured rainfall, increasing to about 35% at the highest measurement station (3200 m.a.s.l.). In contrast to some other tropical mountains, there seems to be no maximum zone of water input, although the gradient remains positive up to the highest altitudes. The unusual precipitation distribution is thought to reflect the contrasting climatological influences operating in the study area.

Abstract:

Recent work on bryophyte diversity in lowland forests of northern South America has suggested the existence of a new type of cloud forest, the ‘tropical lowland cloud forest’ (LCF). LCF occurs in river valleys in hilly areas with high air humidity and morning fog, and is rich in epiphytes. We explored epiphyte abundance and canopy microclimate of LCF in a lowland area (200–400 m asl) near Saül, central French Guiana. We analyzed the vertical distribution of epiphytic cover and biomass on 48 trees, in LCF and in lowland rain forest (LRF) without fog. Trees in LCF had significantly more epiphytic biomass than in LRF; mean total epiphytic biomass in LCF was about 59 g/m2, and 35 g/m2 in LRF. In all height zones on the trees, total epiphyte cover in LCF exceeded that in LRF, with ca 70 percent mean cover in LCF and ca 15 percent in LRF. During both wet and dry seasons, mean diurnal relative air humidity (RH) was higher in LCF than in LRF, and persistence of high RH after sunrise significantly longer in LCF. We suggest that the prolonged availability of high air humidity in LCF and the additional input of liquid water through fog, enhance epiphyte growth in LCF by shortening the desiccation period and lengthening the period of photosynthetic activity of the plants.