The TERENO Pre‐Alpine Observatory: Integrating Meteorological, Hydrological, and Biogeochemical Measurements and Modeling

Abstract

Global change has triggered several transformations, such as alterations in climate, land productivity, water resources, and atmospheric chemistry, with far reaching impacts on ecosystem functions and services. Finding solutions to climate and land cover change-driven impacts on our terrestrial environment is one of the most important scientific challenges of the 21st century, with farreaching interlinkages to the socio-economy. The setup of the German Terrestrial Environmental Observatories (TERENO) Pre-Alpine Observatory was motivated by the fact that mountain areas, such as the pre-alpine region in southern Germany, have been exposed to more intense warming compared with the global average trend and to higher frequencies of extreme hydrological events, such as droughts and intense rainfall. Scientific research questions in the TERENO Pre-Alpine Observatory focus on improved process understanding and closing of combined energy, water, C, and N cycles at site to regional scales. The main long-term objectives of the TERENO Pre-Alpine Observatory include the characterization and quantification of climate change and land cover-management effects on terrestrial hydrology and biogeochemical processes at site and regional scales by joint measuring and modeling approaches. Here we present a detailed climatic and biogeophysical characterization of the TERENO Pre-Alpine Observatory and a summary of novel scientific findings from observations and projects. Finally, we reflect on future directions of climate impact research in this particularly vulnerable region of Germany.

Attribution of N<sub>2</sub>O sources in a grassland soil with laser spectroscopy based isotopocule analysis

“…The TERENO-preAlpine Observatory (Kiese et al, 2018) research site Fendt (De-Fen), a typical montane grassland south of 30 Munich (Germany) is situated at 595 m a.s.l. and has an annual mean temperature of 8.9 °C with 960 mm mean annual precipitation.…”

“…Soil water content was determined within the area (locations are indicated by the dashed square in Figure 1) with five ThetaML2x probes (Delta-T Devices, Cambridge, UK), which integrate soil water content over a soil depth of 0 -6 cm. Water filled pore space (WFPS) was calculated based on measured volumetric water contents and soil characteristics (Kiese et al, 2018). The atmospheric turbulence statistics were determined using the permanently installed micrometeorological instrumentation (Kiese et al 2018) and additional sonic ane-5 mometers installed at 6 m and 9 m above the ground.…”

“…Water filled pore space (WFPS) was calculated based on measured volumetric water contents and soil characteristics (Kiese et al, 2018). The atmospheric turbulence statistics were determined using the permanently installed micrometeorological instrumentation (Kiese et al 2018) and additional sonic ane-5 mometers installed at 6 m and 9 m above the ground. Vertical wind profiles were determined up to 1000 m above the ground in 20 m intervals using Doppler wind-lidar systems (StreamLine, Halo Photonics, Worcestershire, United Kingdom).…”

“…Table 1 Soil characterization of the research site Fendt. Values are given for the topsoil (0-10 cm) according to Kiese et al (2018) . ...................................................................................................................................................................................... 15 Table 2 Mole fractions and isotopic compositions of standard 1 (S1), standard 2 (S2) and target (T) gas cylinders that were 5 used in this study.…”

Surface flux estimates derived from UAS-based mole fraction measurements by means of a nocturnal boundary layer budget approach

“…Fendt is part of the TERENO (Terrestrial Environmental Observatories) network and is extensively instrumented for the purpose of long-term monitoring of land-atmosphere exchange (Mauder et al, 2013;Kiese et al, 2018). Complementary observations were made during the ScaleX 2016 campaign (Wolf et al, 2017).…”