Continuous, high-quality surface-atmosphere flux measurements are difficult to obtain in high-altitude, remote locations like Nam Co and routine maintenance and calibration programs are sometimes challenging to conduct on a regular basis. Because of these challenges, the first PhD project in topic C3 developed and implemented in-depth quality control and correction procedures for the long-term Nam Co eddy covariance dataset and collected supplementary data sets. As a result, a coherently post-processed, homogenous dataset spaning 13 years is now available for further analysis of the carbon and energy exchange between the Nam Co alpine steppe ecosystem and the atmosphere.
In addition to applying the most recent quality control and correction procedures to new data at the site, the objectives of the second PhD project are to (1) analyze the quality of the auxiliary meteorological data, (2) contribute to the maintenance and quality control of the ongoing measurements, (3) identify the dominant environmental drivers of the ecosystem-atmosphere exchange on various time scales and throughout the entire period covered by the dataset. Potentially, additional data from a 20 m boundary layer tower should be included in future analyses.
Using wavelet analysis to be able and account for transitions during the observation period, the project will analyze which variables explain the heat and C fluxes on time scales ranging from hours to weeks, months, and seasons. Wavelet coherence, in addition, allows for testing correlations between signals in the time and frequency domain and their phase shift is a meaningful criterion for a potential cause-and-effect relationship, thereby improving our mechanistic understanding of ecosystems processes and informing model development.
Cooperation within TransTiP:
Jun.-Prof. Dr. Torsten Sachs, TU Braunschweig, GFZ Potsdam
Prof. Dr. Georg Guggenberger, LU Hannover
Prof. Dr. Yaoming Ma, ITP-CAS